This document discusses a study of the distribution of sulfur functional groups in high-sulfur Ledo coals from Assam, India using Temperature Programmed Reduction (TPR). TPR studies were conducted on Ledo coal and model sulfur compounds between 190-6200°C in hydrogen gas. Six hydrogen sulfide evolutions were observed from Ledo coal, which were assigned to specific sulfur functional groups based on the TPR results from model compounds. These included mercaptan/disulfide, thiol, aromatic thioether, thiophene, pyrite, and complex thiophene groups. Additional experiments estimated the thioketonic sulfur content in Ledo coal to be 1.59%. Infrared spectroscopy was also used
The document discusses how the amount of catalyst affects the rate of reaction. It describes two experiments:
1) Using 0.2g of manganese (IV) oxide powder as the catalyst.
2) Using 0.8g of manganese (IV) oxide powder as the catalyst.
The results show that with more catalyst (0.8g), the rate of reaction is faster as shown by the higher volume of oxygen gas liberated over time. Increasing the amount of catalyst increases the rate of reaction.
Removal of cadmium from aqueous solution using cobalt silicate precipitation ...IJSIT Editor
This document discusses the removal of cadmium from aqueous solutions using cobalt silicate precipitation tubes (CoSPT) as an adsorbent. CoSPT was synthesized through a "silica garden" process and found to be an effective adsorbent for cadmium. Batch adsorption studies were conducted to determine the effect of contact time, adsorbent dose, initial cadmium concentration, temperature, and pH. Experimental data fit the Langmuir and Freundlich isotherm models well. Kinetic studies showed that the pseudo-second order model provided the best fit. The maximum adsorption capacity of CoSPT for cadmium was estimated to be 319 mg/g based on
The document describes several experiments investigating factors that affect the rate of reaction of hydrogen peroxide decomposition. It finds that adding a catalyst (manganese IV oxide) increases the reaction rate. Increasing the amount of catalyst or concentration of hydrogen peroxide also increases the reaction rate. Different catalysts have different effectiveness, with manganese IV oxide found to be more effective than iron III oxide.
The Orsat apparatus allows for the analysis of flue gases by passing them through three absorption bulbs containing different solutions. The first bulb contains potassium hydroxide and absorbs carbon dioxide. The second bulb contains alkaline pyrogallic acid and absorbs any remaining carbon dioxide and oxygen. The third bulb contains ammonical cuprous chloride and absorbs any remaining carbon monoxide. By measuring the volume changes in each bulb, the apparatus can determine the percentages of carbon dioxide, oxygen, and carbon monoxide in flue gases, providing information about the completeness of combustion.
The document presents a study on the hydrodynamic behavior of an external loop airlift reactor for two-phase systems. Experiments were conducted to determine the gas holdup and pressure drop characteristics of various electrolyte and solvent solutions at different concentrations and flow rates. The results show that gas holdup increases with superficial gas velocity and solvent concentration but decreases with electrolyte concentration, while pressure drop increases with gas velocity, liquid flow rate, and solution concentration.
1. The student investigated the effect of increasing concentrations of the enzyme inhibitor copper(II)sulfate (0.2, 0.4, 0.6, 0.8, 1.0 mol/dm3) on the activity of the enzyme catalase, measured by the amount of oxygen released during the decomposition of hydrogen peroxide using a data logger.
2. It was hypothesized that there would be a negative correlation between the amount of oxygen released and the concentration of copper(II)sulfate, as the inhibitor would decrease the reaction rate.
3. The results showed that the mean amount of oxygen released decreased with increasing concentrations of copper(II)sulfate at 120, 90, and 60 seconds
Planning Peper 3 ini mengandungi contoh-contoh soalan esei dan contoh jawapan. Di sini juga dsertakan cara-cara untuk menulis operational definition. Diharap murid-murid dapat menggunankan sebagai panduan untuk menguasai teknik menjawab esei paper 3. InsyaAllah..AMIN
Effect of cu co mixed metal oxides on the combustion of psan-htpb based solid...eSAT Journals
Abstract Composite propellants based on ammonium perchlorate (AP) as oxidizer are state-of-the-art. However, global environmental impact restricts AP-based propellants because of their high chlorine exhaust. Therefore, efforts are on to innovate propellants with clean exhaust. Ammonium nitrate (AN) has, thus, regained importance in the field of propellants and explosives, more specifically in insensitive formulations, because of its clean burning and low hazard. However, the stumbling block for the application of AN - as solid propellant oxidizer has been its dimensional instability caused by phase transformation which results in increase of volume and porosity of the propellant grain. This can be overcome by the use of phase stabilized ammonium nitrate (PSAN). In the present study AN phase stabilized by incorporating 10% KN to prepare composite solid propellant. Copper-Cobalt mixed metal oxides have been synthesized via citric acid complexing method. Three different catalysts were prepared with different Cu-Co molar ratios 1, 0.5 And 2 in the initial reactants. The synthesized catalysts were then added to the PSAN-HTPB(Phase Stabilized Ammonium Nitrate- Hydroxyl Terminated Poly-Butadiene) composite formulations. These propellant samples were subjected to burn rate measurement in a Crawford High Pressure Strand Burner and thermal degradation studies in Simultaneous Thermal Analyzer (STA). The thermal decomposition and burn rate of the propellant is observed maximum on the addition of Copper-Cobalt mixed metal oxide catalyst with molar ratio 2. A total of six propellant samples catalyzed and non-catalyzed and one preheated virgin sample were undertaken for the above analysis and results obtained are discussed. It has been observed that except the propellant sample with Cu-Co-III and virgin propellant where PSAN was prepared by solid mixing, other propellant samples were hard to burn. KeyWords:Solid propellants, Ammonium nitrate, Phase stabilization, Burn rate, Thermal decomposition, Mixed metal oxides, Catalytic combustion.
The document discusses how the amount of catalyst affects the rate of reaction. It describes two experiments:
1) Using 0.2g of manganese (IV) oxide powder as the catalyst.
2) Using 0.8g of manganese (IV) oxide powder as the catalyst.
The results show that with more catalyst (0.8g), the rate of reaction is faster as shown by the higher volume of oxygen gas liberated over time. Increasing the amount of catalyst increases the rate of reaction.
Removal of cadmium from aqueous solution using cobalt silicate precipitation ...IJSIT Editor
This document discusses the removal of cadmium from aqueous solutions using cobalt silicate precipitation tubes (CoSPT) as an adsorbent. CoSPT was synthesized through a "silica garden" process and found to be an effective adsorbent for cadmium. Batch adsorption studies were conducted to determine the effect of contact time, adsorbent dose, initial cadmium concentration, temperature, and pH. Experimental data fit the Langmuir and Freundlich isotherm models well. Kinetic studies showed that the pseudo-second order model provided the best fit. The maximum adsorption capacity of CoSPT for cadmium was estimated to be 319 mg/g based on
The document describes several experiments investigating factors that affect the rate of reaction of hydrogen peroxide decomposition. It finds that adding a catalyst (manganese IV oxide) increases the reaction rate. Increasing the amount of catalyst or concentration of hydrogen peroxide also increases the reaction rate. Different catalysts have different effectiveness, with manganese IV oxide found to be more effective than iron III oxide.
The Orsat apparatus allows for the analysis of flue gases by passing them through three absorption bulbs containing different solutions. The first bulb contains potassium hydroxide and absorbs carbon dioxide. The second bulb contains alkaline pyrogallic acid and absorbs any remaining carbon dioxide and oxygen. The third bulb contains ammonical cuprous chloride and absorbs any remaining carbon monoxide. By measuring the volume changes in each bulb, the apparatus can determine the percentages of carbon dioxide, oxygen, and carbon monoxide in flue gases, providing information about the completeness of combustion.
The document presents a study on the hydrodynamic behavior of an external loop airlift reactor for two-phase systems. Experiments were conducted to determine the gas holdup and pressure drop characteristics of various electrolyte and solvent solutions at different concentrations and flow rates. The results show that gas holdup increases with superficial gas velocity and solvent concentration but decreases with electrolyte concentration, while pressure drop increases with gas velocity, liquid flow rate, and solution concentration.
1. The student investigated the effect of increasing concentrations of the enzyme inhibitor copper(II)sulfate (0.2, 0.4, 0.6, 0.8, 1.0 mol/dm3) on the activity of the enzyme catalase, measured by the amount of oxygen released during the decomposition of hydrogen peroxide using a data logger.
2. It was hypothesized that there would be a negative correlation between the amount of oxygen released and the concentration of copper(II)sulfate, as the inhibitor would decrease the reaction rate.
3. The results showed that the mean amount of oxygen released decreased with increasing concentrations of copper(II)sulfate at 120, 90, and 60 seconds
Planning Peper 3 ini mengandungi contoh-contoh soalan esei dan contoh jawapan. Di sini juga dsertakan cara-cara untuk menulis operational definition. Diharap murid-murid dapat menggunankan sebagai panduan untuk menguasai teknik menjawab esei paper 3. InsyaAllah..AMIN
Effect of cu co mixed metal oxides on the combustion of psan-htpb based solid...eSAT Journals
Abstract Composite propellants based on ammonium perchlorate (AP) as oxidizer are state-of-the-art. However, global environmental impact restricts AP-based propellants because of their high chlorine exhaust. Therefore, efforts are on to innovate propellants with clean exhaust. Ammonium nitrate (AN) has, thus, regained importance in the field of propellants and explosives, more specifically in insensitive formulations, because of its clean burning and low hazard. However, the stumbling block for the application of AN - as solid propellant oxidizer has been its dimensional instability caused by phase transformation which results in increase of volume and porosity of the propellant grain. This can be overcome by the use of phase stabilized ammonium nitrate (PSAN). In the present study AN phase stabilized by incorporating 10% KN to prepare composite solid propellant. Copper-Cobalt mixed metal oxides have been synthesized via citric acid complexing method. Three different catalysts were prepared with different Cu-Co molar ratios 1, 0.5 And 2 in the initial reactants. The synthesized catalysts were then added to the PSAN-HTPB(Phase Stabilized Ammonium Nitrate- Hydroxyl Terminated Poly-Butadiene) composite formulations. These propellant samples were subjected to burn rate measurement in a Crawford High Pressure Strand Burner and thermal degradation studies in Simultaneous Thermal Analyzer (STA). The thermal decomposition and burn rate of the propellant is observed maximum on the addition of Copper-Cobalt mixed metal oxide catalyst with molar ratio 2. A total of six propellant samples catalyzed and non-catalyzed and one preheated virgin sample were undertaken for the above analysis and results obtained are discussed. It has been observed that except the propellant sample with Cu-Co-III and virgin propellant where PSAN was prepared by solid mixing, other propellant samples were hard to burn. KeyWords:Solid propellants, Ammonium nitrate, Phase stabilization, Burn rate, Thermal decomposition, Mixed metal oxides, Catalytic combustion.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This study examined how pH and redox potential (Eh) influence the leaching of mercury from mining waste materials. Laboratory experiments were conducted by varying the pH from 2 to 12 and Eh under different gas purging conditions. Results showed that mercury concentration in leachates increased with rising pH until pH 10.65, above which it sharply decreased. The presence of iron significantly reduced mercury concentrations by 1/10th to 1/100th. Varying the Eh had little effect on mercury leaching, except when hydrogen peroxide was added to increase Eh, which sharply increased mercury levels. Alkaline and reduced conditions enhanced mercury solubility the most.
The document describes an in situ study using UV-visible spectroscopy to measure the kinetics of propane oxidative dehydrogenation (ODH) on vanadium oxide catalysts. Transients in UV-visible intensity during ODH reactions were analyzed using a surface reaction mechanism. Rate constants for the kinetically relevant C-H bond activation step were determined and compared to values from steady-state ODH rates. The ratio of these values provides a measure of the fraction of active vanadium sites. Reoxidation rate constants, which cannot be obtained from steady-state analysis, were also determined and found to be orders of magnitude larger than C-H bond activation rates.
Laboratory investigation of insecticide O,O diethyl O-2 isopropyl 6- methyl pyrimidin-4-yl phosphorothioate insecticide adsorption using olive stones activated by phosphoric acid was carried out. The influence of several factors governing insecticide adsorption such as dosage, temperature, pH and time in addition to specific surface area of the prepared carbon was investigated. The obtained results showed that the adsorption was found to increase with increasing temperature and pH and the activated carbon prepared from olive stones has higher surface area (>700 m2g-1). Also, the removal of insecticide increased with the lapse of time; an olive stone activated by phosphoric acid has 75.6 % insecticide removal efficiency in comparison with that of activated carbon. The experimental results have been fitted with Langmuir and Freundlich isotherms. The Langmuir isotherm better fitted the experimental data since the average percent deviations were lower than with Freundlich isotherm. Moreover, activated carbon from olive stones is a suitable adsorbent and adsorption of 90% is possible in the high temperature, pH and adsorbent dosages.
Lab 4 alkalinity –acidity and determination of alkalinity in waterAnas Maghayreh
Environmental lab
Lab 4 alkalinity –acidity and determination of alkalinity in water
experiment at JORDAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
by: ANAS MAGHAYREH
Ftir and xrd evaluation of carbonated hydroxyapatite powders synthesized by w...Chienbinhrong Bj
This document summarizes a study that evaluated carbonated hydroxyapatite powders synthesized by wet methods using FTIR and XRD analysis. The following key points were made:
1) Carbonated hydroxyapatite powders were produced using various calcium and phosphate reagents with NH4HCO3 or NaHCO3 additions to incorporate carbonate ions.
2) FTIR and XRD analysis showed the powders contained carbonate substitutions and were classified as type B or AB apatites.
3) The amount and type of carbonate additive, as well as calcination temperature, influenced the level of carbonate substitution and thermal stability of the hydroxyapatite structure. Higher amounts and
11.mass transfer coefficient evaluation for lab scale fermenter using sodium ...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The results showed that the mass transfer coefficient increases with decreasing impeller speed and increasing airflow rate. The study aimed to optimize conditions for the maximum mass transfer coefficient.
Mass transfer coefficient evaluation for lab scale fermenter using sodium sul...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The mass transfer coefficient was found to increase with decreasing impeller speed and increasing airflow rate. The study aimed to optimize the mass transfer coefficient using statistical experimental design.
CHEMISTRY INTERNAL ASSESMENT| CHEM IA ZainAhmed119
The document describes an experiment to investigate the correlation between ligands (Cl−, NH3, H2O, OH−) and the wavelength of light absorbed by transition metal complexes. Transition metal complexes of Cu2+, Co2+, Fe2+, Cr2+ were made using the different ligands. A colorimeter was used to measure the wavelength absorbed for each complex. The results showed the wavelength absorbed was longest for Cl− ligand and shortest for NH3 ligand for all metal complexes. This trend was consistent with the hypothesis and previous research that ligand type affects d-orbital splitting and thus the energy of electronic transitions determining color.
A simple simulation model for oxidative coupling of methaneAlexander Decker
This document describes a study that developed a mathematical model to simulate the oxidative coupling of methane over a La0.6Sr0.4NiO3 perovskite catalyst. The catalyst was prepared using a reverse microemulsion method and characterized using various techniques. Rate equations were developed based on previous studies of similar catalysts. The model can predict that at temperatures of 925°C or higher, with a methane partial pressure of 0.3 and oxygen partial pressure of 0.1, the catalyst will reach around 10% methane conversion and 50% selectivity to C2+ hydrocarbons.
Adsorption process for voc (volatile organic compounds copySaiful Islam
The document discusses the adsorption process for removing volatile organic compounds (VOCs) from air or gas streams. It defines adsorption and describes how VOCs accumulate on the surface of adsorbent materials like activated carbon. Fixed bed adsorption is commonly used, where the VOCs are removed as the contaminated air passes through a column packed with adsorbent. Key factors that influence the adsorption process include temperature, gas concentration, bed length, and regeneration of the adsorbent material. Common adsorbents for VOC removal include activated carbon beads and fibers, which can be used in continuous adsorption/desorption systems.
This document summarizes a study on the leaching behavior of cobaltous oxide (CoO) and cobalto-cobaltic oxide (Co3O4) in ammonia and acid solutions. The dissolution of cobaltous oxide was found to be chemically controlled, with apparent activation energies of 54.0 kJ/mol and 56.5 kJ/mol in ammonia and acid solutions, respectively. The dissolution rate of cobalto-cobaltic oxide in ammonia-ammonium carbonate was very slow at low temperatures. At higher temperatures, less than 2 x 10-5 mol/dm3 of cobalt remained in solution due to precipitation of cobalt carbonate and cobalto-cobalt
Optimal Heat Exchanger Rating Models for Isothermal CSTR SO3 Hydration Using ...INFOGAIN PUBLICATION
This work deals with the development of design models for heat exchanger rating in catalytic sulphur trioxide hydration process at isothermal condition exploiting the Abowei and Goodhead derived continuous adsorption tower (CAST) heat generation per unit volume equations at constant temperature. Shell and Tube heat exchanger is invoked for this studies resulting to novel design equations which were stochastically examined and found to be capable of simulating the rating performance dimensions as a function of kinetic parameters. The rating performance models were further generalized to inculcate fractional conversion functionality. The novel design models were simulation to evaluate the overall heat transfer coefficient, mass flow rate of cooling fluid, tube side cross flow area and tube side film coefficient using Matlab R2007B within the operational limits of conversion degree at constant temperature. The heat exchanger is used for the removal of heat generated per reactor unit volume utilizing water as cooling fluid, enters the shell side at 25oC flowing counter currently to the tube side at exit temperature of 85oC in order to maintaining 97oC isothermal condition. The configuration of the exchanger is U–tube type and is three (3) shell and six (6) tube passes. The results of the rating dimensions showed a dependable relationship with fractional conversion at constant temperature for various reactor radius and number of tubes.
Qualitative and Quantitative Analysis, Empirical and Molecular FormulaFawad Mueen Arbi
This document discusses qualitative and quantitative analysis, empirical and molecular formulas, and combustion analysis. It provides details on:
- The differences between qualitative analysis, which identifies substances, and quantitative analysis, which determines amounts.
- How empirical formulas represent the simplest whole number ratio of elements in a compound and molecular formulas use actual atom counts.
- The process of combustion analysis, where a compound is burned and the products analyzed to determine the empirical formula based on the amounts of carbon dioxide and water produced.
The document provides an introduction and overview of the Orsat apparatus, which is a piece of laboratory equipment used to analyze gas samples, typically flue gas, for their oxygen, carbon monoxide, and carbon dioxide content. It describes the basic components and workings of the Orsat apparatus, including the gas burette, absorption pipettes containing chemical solutions to absorb specific gases, and operating procedures to collect and pass the gas sample through the solutions to measure gas concentrations. Modern analyzers have been derived from the Orsat apparatus to continuously measure gas composition in process flows.
This document provides a procedure for determining the alkalinity of water samples. Alkalinity is measured through acid-base titration and is important as it indicates a water sample's ability to resist changes in pH. The procedure involves titrating the sample with sulfuric acid using phenolphthalein and methyl orange indicators. The titrations are used to determine the phenolphthalein alkalinity and total alkalinity in mg/L of calcium carbonate. For the given water sample, the phenolphthalein alkalinity was found to be 0 while the total alkalinity was determined to be 65 mg/L, within the recommended limit of less than 200 mg/L.
The document summarizes an experiment investigating fac/mer isomerism in a low spin iron(II) complex. A complex was synthesized from iron(II) tetrafluoroborate, benzylamine, and 2-pyridinecarboxaldehyde, yielding 79.7% product. NMR showed a high ratio of facial to meridional isomers. UV-vis spectroscopy determined molar extinction coefficients of 6081.9 and 4518.4 L/mol-cm at 516.5 and 561.3 nm, respectively.
Effects of Ionic Strength and pH on Arsenic Mobilization from Arsenopyrite_Ch...Chloe An
This document summarizes a study that investigated the effects of ionic strength and pH on arsenic mobilization from arsenopyrite in managed aquifer recharge systems. The study found that:
1) In sodium nitrate systems, the lowest arsenic levels occurred at pH 5 due to a balance between arsenic mobilization from dissolution and sorption by ferrihydrite; the highest levels were at pH 3 and 7.
2) In sodium chloride systems, arsenic levels were highest at lower pHs due to inhibited ferrihydrite formation from chloride; the lowest levels occurred at pH 7.
3) For sodium nitrate systems, arsenic levels were generally highest at 10mM ion
Kinetics of Ruthenium(III) Catalyzed and Uncatalyzed Oxidation of Monoethanol...Ratnakaram Venkata Nadh
Kinetics of uncatalyzed and ruthenium(III) catalyzed oxidation of monoethanolamine by N-bromosuccinimide
(NBS) has been studied in an aqueous acetic acid medium in the presence of sodium acetate
and perchloric acid, respectively. In the uncatalyzed oxidation the kinetic orders are: the first order in NBS,
a fractional order in the substrate. The rate of the reaction increased with an increase in the sodium acetate
concentration and decreased with an increase in the perchloric acid concentration. This indicates that free
amine molecules are the reactive species. Addition of halide ions results in a decrease in the kinetic rate,
which is noteworthy. Both in absence and presence of a catalyst, a decrease in the dielectric constant of the
medium decreases the kinetic rate pointing out that these are dipole—dipole reactions. A relatively higher
oxidation state of ruthenium i.e., Ru(V) was found to be the active species in Ru(III) catalyzed reactions. A
suitable mechanism consistent with the observations has been proposed and a rate law has been derived to
explain the kinetic orders.
There are three sources of alkalinity in water samples: hydroxide, carbonate, and bicarbonate alkalinity. The alkalinity method involves titrating a water sample from its original pH down to pH 8.3 to determine hydroxide and carbonate alkalinity. The sample is then titrated down to pH 4.5 to determine total alkalinity. Calculations are performed based on the volumes of acid added and normality to quantify each alkalinity type in units of mg/L as CaCO3. The source and amount of each alkalinity present depends on the initial pH and volume of acid needed to reach pH 8.3 versus the total volume to pH 4.
Video Streaming Compression for Wireless Multimedia Sensor NetworksIOSR Journals
This document discusses video streaming compression for wireless multimedia sensor networks. It proposes a cross-layer system that jointly controls the video encoding rate, transmission rate, and uses an adaptive parity scheme. At the application layer, video is compressed and divided into packets. These packets are encoded at the transport layer and forwarded through the network layer. An active buffer management scheme and adaptive parity check are used to maximize received video quality over lossy wireless links. Simulation results show the proposed techniques can achieve higher throughput by resequencing dropped packets. The goal is to design an efficient system for wireless transmission of compressed video that optimizes video quality.
A Novel Rebroadcast Technique for Reducing Routing Overhead In Mobile Ad Hoc ...IOSR Journals
This document presents a novel rebroadcast technique called Neighbor Coverage based Probabilistic Rebroadcast (NCPR) protocol to reduce routing overhead in mobile ad hoc networks. The NCPR protocol calculates a rebroadcast delay based on the number of common neighbors between nodes to prioritize dissemination of neighbor information. It also calculates a rebroadcast probability based on additional neighbor coverage ratio and connectivity factor to reduce unnecessary rebroadcasts while maintaining network connectivity. The protocol is implemented by enhancing the AODV routing protocol in NS-2 to reduce overhead from hello packets and neighbor lists in route requests. Its performance is evaluated under varying network sizes, traffic loads, and packet loss conditions.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This study examined how pH and redox potential (Eh) influence the leaching of mercury from mining waste materials. Laboratory experiments were conducted by varying the pH from 2 to 12 and Eh under different gas purging conditions. Results showed that mercury concentration in leachates increased with rising pH until pH 10.65, above which it sharply decreased. The presence of iron significantly reduced mercury concentrations by 1/10th to 1/100th. Varying the Eh had little effect on mercury leaching, except when hydrogen peroxide was added to increase Eh, which sharply increased mercury levels. Alkaline and reduced conditions enhanced mercury solubility the most.
The document describes an in situ study using UV-visible spectroscopy to measure the kinetics of propane oxidative dehydrogenation (ODH) on vanadium oxide catalysts. Transients in UV-visible intensity during ODH reactions were analyzed using a surface reaction mechanism. Rate constants for the kinetically relevant C-H bond activation step were determined and compared to values from steady-state ODH rates. The ratio of these values provides a measure of the fraction of active vanadium sites. Reoxidation rate constants, which cannot be obtained from steady-state analysis, were also determined and found to be orders of magnitude larger than C-H bond activation rates.
Laboratory investigation of insecticide O,O diethyl O-2 isopropyl 6- methyl pyrimidin-4-yl phosphorothioate insecticide adsorption using olive stones activated by phosphoric acid was carried out. The influence of several factors governing insecticide adsorption such as dosage, temperature, pH and time in addition to specific surface area of the prepared carbon was investigated. The obtained results showed that the adsorption was found to increase with increasing temperature and pH and the activated carbon prepared from olive stones has higher surface area (>700 m2g-1). Also, the removal of insecticide increased with the lapse of time; an olive stone activated by phosphoric acid has 75.6 % insecticide removal efficiency in comparison with that of activated carbon. The experimental results have been fitted with Langmuir and Freundlich isotherms. The Langmuir isotherm better fitted the experimental data since the average percent deviations were lower than with Freundlich isotherm. Moreover, activated carbon from olive stones is a suitable adsorbent and adsorption of 90% is possible in the high temperature, pH and adsorbent dosages.
Lab 4 alkalinity –acidity and determination of alkalinity in waterAnas Maghayreh
Environmental lab
Lab 4 alkalinity –acidity and determination of alkalinity in water
experiment at JORDAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
by: ANAS MAGHAYREH
Ftir and xrd evaluation of carbonated hydroxyapatite powders synthesized by w...Chienbinhrong Bj
This document summarizes a study that evaluated carbonated hydroxyapatite powders synthesized by wet methods using FTIR and XRD analysis. The following key points were made:
1) Carbonated hydroxyapatite powders were produced using various calcium and phosphate reagents with NH4HCO3 or NaHCO3 additions to incorporate carbonate ions.
2) FTIR and XRD analysis showed the powders contained carbonate substitutions and were classified as type B or AB apatites.
3) The amount and type of carbonate additive, as well as calcination temperature, influenced the level of carbonate substitution and thermal stability of the hydroxyapatite structure. Higher amounts and
11.mass transfer coefficient evaluation for lab scale fermenter using sodium ...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The results showed that the mass transfer coefficient increases with decreasing impeller speed and increasing airflow rate. The study aimed to optimize conditions for the maximum mass transfer coefficient.
Mass transfer coefficient evaluation for lab scale fermenter using sodium sul...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The mass transfer coefficient was found to increase with decreasing impeller speed and increasing airflow rate. The study aimed to optimize the mass transfer coefficient using statistical experimental design.
CHEMISTRY INTERNAL ASSESMENT| CHEM IA ZainAhmed119
The document describes an experiment to investigate the correlation between ligands (Cl−, NH3, H2O, OH−) and the wavelength of light absorbed by transition metal complexes. Transition metal complexes of Cu2+, Co2+, Fe2+, Cr2+ were made using the different ligands. A colorimeter was used to measure the wavelength absorbed for each complex. The results showed the wavelength absorbed was longest for Cl− ligand and shortest for NH3 ligand for all metal complexes. This trend was consistent with the hypothesis and previous research that ligand type affects d-orbital splitting and thus the energy of electronic transitions determining color.
A simple simulation model for oxidative coupling of methaneAlexander Decker
This document describes a study that developed a mathematical model to simulate the oxidative coupling of methane over a La0.6Sr0.4NiO3 perovskite catalyst. The catalyst was prepared using a reverse microemulsion method and characterized using various techniques. Rate equations were developed based on previous studies of similar catalysts. The model can predict that at temperatures of 925°C or higher, with a methane partial pressure of 0.3 and oxygen partial pressure of 0.1, the catalyst will reach around 10% methane conversion and 50% selectivity to C2+ hydrocarbons.
Adsorption process for voc (volatile organic compounds copySaiful Islam
The document discusses the adsorption process for removing volatile organic compounds (VOCs) from air or gas streams. It defines adsorption and describes how VOCs accumulate on the surface of adsorbent materials like activated carbon. Fixed bed adsorption is commonly used, where the VOCs are removed as the contaminated air passes through a column packed with adsorbent. Key factors that influence the adsorption process include temperature, gas concentration, bed length, and regeneration of the adsorbent material. Common adsorbents for VOC removal include activated carbon beads and fibers, which can be used in continuous adsorption/desorption systems.
This document summarizes a study on the leaching behavior of cobaltous oxide (CoO) and cobalto-cobaltic oxide (Co3O4) in ammonia and acid solutions. The dissolution of cobaltous oxide was found to be chemically controlled, with apparent activation energies of 54.0 kJ/mol and 56.5 kJ/mol in ammonia and acid solutions, respectively. The dissolution rate of cobalto-cobaltic oxide in ammonia-ammonium carbonate was very slow at low temperatures. At higher temperatures, less than 2 x 10-5 mol/dm3 of cobalt remained in solution due to precipitation of cobalt carbonate and cobalto-cobalt
Optimal Heat Exchanger Rating Models for Isothermal CSTR SO3 Hydration Using ...INFOGAIN PUBLICATION
This work deals with the development of design models for heat exchanger rating in catalytic sulphur trioxide hydration process at isothermal condition exploiting the Abowei and Goodhead derived continuous adsorption tower (CAST) heat generation per unit volume equations at constant temperature. Shell and Tube heat exchanger is invoked for this studies resulting to novel design equations which were stochastically examined and found to be capable of simulating the rating performance dimensions as a function of kinetic parameters. The rating performance models were further generalized to inculcate fractional conversion functionality. The novel design models were simulation to evaluate the overall heat transfer coefficient, mass flow rate of cooling fluid, tube side cross flow area and tube side film coefficient using Matlab R2007B within the operational limits of conversion degree at constant temperature. The heat exchanger is used for the removal of heat generated per reactor unit volume utilizing water as cooling fluid, enters the shell side at 25oC flowing counter currently to the tube side at exit temperature of 85oC in order to maintaining 97oC isothermal condition. The configuration of the exchanger is U–tube type and is three (3) shell and six (6) tube passes. The results of the rating dimensions showed a dependable relationship with fractional conversion at constant temperature for various reactor radius and number of tubes.
Qualitative and Quantitative Analysis, Empirical and Molecular FormulaFawad Mueen Arbi
This document discusses qualitative and quantitative analysis, empirical and molecular formulas, and combustion analysis. It provides details on:
- The differences between qualitative analysis, which identifies substances, and quantitative analysis, which determines amounts.
- How empirical formulas represent the simplest whole number ratio of elements in a compound and molecular formulas use actual atom counts.
- The process of combustion analysis, where a compound is burned and the products analyzed to determine the empirical formula based on the amounts of carbon dioxide and water produced.
The document provides an introduction and overview of the Orsat apparatus, which is a piece of laboratory equipment used to analyze gas samples, typically flue gas, for their oxygen, carbon monoxide, and carbon dioxide content. It describes the basic components and workings of the Orsat apparatus, including the gas burette, absorption pipettes containing chemical solutions to absorb specific gases, and operating procedures to collect and pass the gas sample through the solutions to measure gas concentrations. Modern analyzers have been derived from the Orsat apparatus to continuously measure gas composition in process flows.
This document provides a procedure for determining the alkalinity of water samples. Alkalinity is measured through acid-base titration and is important as it indicates a water sample's ability to resist changes in pH. The procedure involves titrating the sample with sulfuric acid using phenolphthalein and methyl orange indicators. The titrations are used to determine the phenolphthalein alkalinity and total alkalinity in mg/L of calcium carbonate. For the given water sample, the phenolphthalein alkalinity was found to be 0 while the total alkalinity was determined to be 65 mg/L, within the recommended limit of less than 200 mg/L.
The document summarizes an experiment investigating fac/mer isomerism in a low spin iron(II) complex. A complex was synthesized from iron(II) tetrafluoroborate, benzylamine, and 2-pyridinecarboxaldehyde, yielding 79.7% product. NMR showed a high ratio of facial to meridional isomers. UV-vis spectroscopy determined molar extinction coefficients of 6081.9 and 4518.4 L/mol-cm at 516.5 and 561.3 nm, respectively.
Effects of Ionic Strength and pH on Arsenic Mobilization from Arsenopyrite_Ch...Chloe An
This document summarizes a study that investigated the effects of ionic strength and pH on arsenic mobilization from arsenopyrite in managed aquifer recharge systems. The study found that:
1) In sodium nitrate systems, the lowest arsenic levels occurred at pH 5 due to a balance between arsenic mobilization from dissolution and sorption by ferrihydrite; the highest levels were at pH 3 and 7.
2) In sodium chloride systems, arsenic levels were highest at lower pHs due to inhibited ferrihydrite formation from chloride; the lowest levels occurred at pH 7.
3) For sodium nitrate systems, arsenic levels were generally highest at 10mM ion
Kinetics of Ruthenium(III) Catalyzed and Uncatalyzed Oxidation of Monoethanol...Ratnakaram Venkata Nadh
Kinetics of uncatalyzed and ruthenium(III) catalyzed oxidation of monoethanolamine by N-bromosuccinimide
(NBS) has been studied in an aqueous acetic acid medium in the presence of sodium acetate
and perchloric acid, respectively. In the uncatalyzed oxidation the kinetic orders are: the first order in NBS,
a fractional order in the substrate. The rate of the reaction increased with an increase in the sodium acetate
concentration and decreased with an increase in the perchloric acid concentration. This indicates that free
amine molecules are the reactive species. Addition of halide ions results in a decrease in the kinetic rate,
which is noteworthy. Both in absence and presence of a catalyst, a decrease in the dielectric constant of the
medium decreases the kinetic rate pointing out that these are dipole—dipole reactions. A relatively higher
oxidation state of ruthenium i.e., Ru(V) was found to be the active species in Ru(III) catalyzed reactions. A
suitable mechanism consistent with the observations has been proposed and a rate law has been derived to
explain the kinetic orders.
There are three sources of alkalinity in water samples: hydroxide, carbonate, and bicarbonate alkalinity. The alkalinity method involves titrating a water sample from its original pH down to pH 8.3 to determine hydroxide and carbonate alkalinity. The sample is then titrated down to pH 4.5 to determine total alkalinity. Calculations are performed based on the volumes of acid added and normality to quantify each alkalinity type in units of mg/L as CaCO3. The source and amount of each alkalinity present depends on the initial pH and volume of acid needed to reach pH 8.3 versus the total volume to pH 4.
Video Streaming Compression for Wireless Multimedia Sensor NetworksIOSR Journals
This document discusses video streaming compression for wireless multimedia sensor networks. It proposes a cross-layer system that jointly controls the video encoding rate, transmission rate, and uses an adaptive parity scheme. At the application layer, video is compressed and divided into packets. These packets are encoded at the transport layer and forwarded through the network layer. An active buffer management scheme and adaptive parity check are used to maximize received video quality over lossy wireless links. Simulation results show the proposed techniques can achieve higher throughput by resequencing dropped packets. The goal is to design an efficient system for wireless transmission of compressed video that optimizes video quality.
A Novel Rebroadcast Technique for Reducing Routing Overhead In Mobile Ad Hoc ...IOSR Journals
This document presents a novel rebroadcast technique called Neighbor Coverage based Probabilistic Rebroadcast (NCPR) protocol to reduce routing overhead in mobile ad hoc networks. The NCPR protocol calculates a rebroadcast delay based on the number of common neighbors between nodes to prioritize dissemination of neighbor information. It also calculates a rebroadcast probability based on additional neighbor coverage ratio and connectivity factor to reduce unnecessary rebroadcasts while maintaining network connectivity. The protocol is implemented by enhancing the AODV routing protocol in NS-2 to reduce overhead from hello packets and neighbor lists in route requests. Its performance is evaluated under varying network sizes, traffic loads, and packet loss conditions.
Generation and Implementation of Barker and Nested Binary codesIOSR Journals
This document discusses the generation and implementation of Barker and nested binary codes for use in radar applications. It begins with background on Barker codes and nested binary codes, which are types of phase coded waveforms used for pulse compression. Barker codes have the optimal autocorrelation sidelobe properties but are limited in length. Nested binary codes are formed by taking the Kronecker product of two Barker codes, which allows the generation of longer codes while maintaining good autocorrelation. The document then presents the methodology for implementing Barker and nested binary codes using linear feedback shift registers (LFSRs). Finally, it discusses measures for comparing signal performance such as merit factor and proposes an efficient VLSI architecture using LFSRs to generate these codes for implementation
Low Leakage Low Ground Bounce Noise Power Gating Techniques for FPGAsIOSR Journals
This document analyzes and compares different power gating techniques to reduce leakage current and ground bounce noise in FPGAs. It discusses stacking power gating, diode-based stacking power gating, and diode-based staggered phase damping techniques applied to a benchmark 74182 carry look ahead adder circuit implemented as a lookup table (LUT) in FPGAs. Simulation results show that the diode-based staggered phase damping technique provides up to 99% reduction in ground bounce noise and 75% reduction in leakage current. Performance analysis of the LUT implemented on different FPGAs also shows the diode-based staggered phase damping technique to be most effective at reducing leakage current and ground bounce noise.
Enhance similarity searching algorithm with optimized fast population count m...IOSR Journals
This document describes research on enhancing similarity searching algorithms for drug discovery applications using optimized parallel computing methods. The researchers developed parallel implementations of a fast population count method for calculating Tanimoto similarity coefficients on both OpenMP and CUDA platforms. In the pre-computing stage, fingerprint data from chemical databases is converted to integer arrays to reduce memory usage. The fast population count method is then applied in parallel to count the number of 1 bits in fingerprint bitstrings more efficiently. The goal is to speed up similarity searches for virtual drug screening without hardware-specific GPU functions and achieve good performance on portable systems. Evaluation on different sized chemical databases showed significant speedups compared to sequential implementations.
Fast Human Detection in Surveillance VideoIOSR Journals
This document proposes a fast and efficient algorithm for tracking humans in indoor surveillance videos. It uses HOG features and correlation-based methods. Candidate frames are selected using strips along the borders to detect new objects entering the frame. HOG features are extracted only on candidate frames to reduce computation time. A correlation-based method then tracks humans between frames using the highest correlated sample window as the tracked window. Experimental results showed over 86% detection rates on test videos totalling over 6 hours, demonstrating the algorithm can detect and track humans in real-time surveillance applications.
Efficiency of Optical Fiber Communication for Dissemination of Information wi...IOSR Journals
This document summarizes the efficiency of using optical fiber communication for disseminating information within power system networks. It discusses how fiber optic cables can replace traditional communication methods like power line carriers and microwave radio systems. Fiber optic technology offers high bandwidth capacity and signal consistency over long distances. It also has advantages like high immunity to electromagnetic interference. The document then reviews different methods for overhead installation of fiber cables on power lines, as well as the advantages of using power infrastructure for fiber deployment, including speed, security, and lower costs compared to underground installation. Various types of fiber optic cables and potential points of failure in fiber networks are also summarized.
Improvement of QoS Contained by AODV Routing Protocol On the Basis of Varying...IOSR Journals
The document proposes improvements to the AODV routing protocol in mobile ad hoc networks to enhance quality of service. It introduces two techniques: 1) Using a dynamic time-to-live value rather than a fixed value to establish connections over longer routes. 2) Implementing a varying queue length technique where the queue size increases instead of dropping packets if the node buffer is full, to minimize packet loss. The performance of the improved AODV protocol is evaluated based on metrics like packet delivery ratio, routing overhead, and throughput, and shows better results compared to the normal AODV protocol.
Detecting Spam Tags Against Collaborative Unfair Through Trust ModellingIOSR Journals
This document discusses methods for detecting spam tags in collaborative tagging systems through trust modeling. It classifies existing approaches into content trust modeling and user trust modeling. Content trust modeling assigns trust scores to content based on tags and users associated with it, while user trust modeling assigns trust scores to users based on their tagging behavior. The document also discusses challenges like evaluating models on multilingual data and lack of publicly available datasets for comparison. It concludes that trust modeling is important for enhancing reliability of social networks and content sharing services.
Cascaded Multilevel Inverter Based Active Power Filters: A Survey of ControlsIOSR Journals
This document summarizes several control strategies for cascaded multilevel inverter based active power filters, including:
1. P-q theory with PI controller, which calculates real and reactive power to generate reference currents but has errors when voltages are distorted.
2. Average power method with carrier phase shifted PWM, which gives accurate results even with distorted voltages by using a PLL and calculating average power.
3. Instantaneous real-power theory with triangular-sampling current modulator, which generates reference currents to compensate for harmonics and reactive power in real-time using simple calculations. It maintains the DC bus voltage and works for generic power systems.
Mobility Contrast Effect on Environment in Manet as Mobility ModelIOSR Journals
The document discusses mobility models in mobile ad hoc networks (MANETs). It describes several types of mobility models including:
1) Random mobility models like the random waypoint, random walk, and random direction models.
2) Group mobility models like the referential point group, nomadic community, and column models.
3) Map-based models like the Manhattan and freeway models.
4) Particle-based models like the pedestrian mobility model. The models have different characteristics that affect the performance of routing protocols in MANETs.
Simulation And Hardware Analysis Of Three Phase PWM Rectifier With Power Fact...IOSR Journals
This document summarizes a research paper on simulating and analyzing a three-phase PWM rectifier with power factor correction. The paper describes the design of a three-phase PWM rectifier circuit to convert AC power input into DC power output at unity power factor. Simulation results show that the rectifier controls input currents to be sinusoidal and in phase with voltages, improving power quality. Hardware testing also demonstrates unity power factor with voltage and current waveforms in phase. The rectifier design and simulation aim to improve power quality by controlling reactive power and achieving unity power factor.
Automatic Learning Image Objects via Incremental ModelIOSR Journals
This document presents a novel approach for automatically collecting and learning object category datasets and models in an incremental manner by leveraging web image resources. The proposed framework uses object recognition techniques to iteratively accumulate model knowledge and image examples, mimicking human learning. An incremental learning algorithm is used to automatically collect larger object category datasets than existing datasets like Caltech 101. As new images are classified and added in each iteration, the object model becomes more robust, leading to an even larger and more accurate collected dataset. Experiments show the approach is effective at collecting superior image datasets compared to existing resources.
Gene Selection for Sample Classification in Microarray: Clustering Based MethodIOSR Journals
This document describes a clustering-based method for gene selection to classify samples in microarray data. It involves calculating the relevance of each gene to class labels and the redundancy between genes using mutual information. Genes are clustered based on their relevance, with the most relevant gene selected as the cluster representative. Min-hash clustering is then applied to reduce redundant genes and cluster size. The goal is to select a minimal set of non-redundant genes that can accurately classify samples by reducing noise from irrelevant genes.
An Efficient Biological Sequence Compression Technique Using LUT and Repeat ...IOSR Journals
This document presents two improved biological sequence compression algorithms that utilize a lookup table (LUT) and identification of tandem repeats in sequences. The first algorithm maps all possible 3-character combinations to ASCII characters using a 125-entry LUT. The second maps all possible 4-character combinations to ASCII characters using a 256-entry LUT. These algorithms aim to achieve high compression factors, saving percentages, and faster compression/decompression times compared to previous biological sequence compression methods.
Analyzing the Effect of Varying CBR on AODV, DSR, IERP Routing Protocols in M...IOSR Journals
This document analyzes the performance of the AODV, DSR, and IERP routing protocols in a mobile ad hoc network (MANET) with varying constant bit rate (CBR) traffic loads. It conducts simulations in QualNet 6.1 and evaluates the protocols based on average end-to-end delay, throughput, average jitter, and packet delivery ratio under different CBR values. The results show that AODV generally performs best with low and stable delay, jitter and high throughput and delivery ratio. DSR has better performance than IERP for throughput and delivery ratio. IERP shows the worst performance for delay and jitter as CBR increases. The document concludes by stating AODV is best overall but
A Mat Lab built software application for similar image retrievalIOSR Journals
This document describes a Matlab software application for similar image retrieval that uses shape and color features. It discusses extracting edge features through horizontal, vertical, diagonal and anti-diagonal masks. It also discusses extracting color features by converting images to HSV color space and generating 128-bin color histograms. Features of images in a database are stored in a 'features.mat' file. For a query image, its features are compared to those in the database using Euclidean distance to find similar images. The most similar images based on feature similarity are displayed at the top of the results. The software provides image retrieval based on fusing color and shape features.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Auto Finding and Resolving Distributed Firewall PolicyIOSR Journals
This document presents a method for automatically finding and resolving anomalies in distributed firewall policies. It proposes using rule-based segmentation and a grid-based representation to partition firewall rules into disjoint packet spaces to identify policy anomalies like conflicts and redundancies. The paper describes implementing this approach in a tool called FAME that can discover and resolve anomalies by reordering rules. Experimental results show FAME achieved around 92% conflict resolution and improved network security and availability. The method aims to effectively manage anomalies in distributed firewall environments.
High Security Cryptographic Technique Using Steganography and Chaotic Image E...IOSR Journals
This document summarizes a proposed cryptographic technique that combines steganography and chaotic image encryption to provide high security. Steganography is used to hide a message within a cover image by embedding it in the least significant bits of pixel values without affecting image quality. The resulting stego-image is then encrypted using triple-key chaotic image encryption based on the logistic map, making the encrypted data highly sensitive to changes in the initial encryption keys. The technique provides four layers of security to securely transmit hidden messages within digital images.
This document summarizes research on synthesizing sulfur-functionalized ordered mesoporous carbons and examining their ability to adsorb heavy metals like mercury, lead, cadmium, and nickel from aqueous solutions. Sodium thiosulfate was used to introduce sulfur functional groups onto mesoporous carbons during high-temperature activation. The sulfur-treated carbons had higher surface areas and pore volumes than untreated carbon. Adsorption tests showed mercury and lead were strongly adsorbed in a pH-dependent manner, while cadmium and nickel adsorption was less. XPS analysis identified chemical forms of adsorbed metals. The highest sulfur carbon effectively separated heavy metals from solution in both individual and competitive adsorption
Madkour-1986-Journal_of_Chemical_Technology_and_BiotechnologyAl Baha University
This document summarizes a theoretical study on the sulphate roasting of Umm-Gheig carbonate ore from Egypt to make it suitable for zinc electrowinning. Thermodynamic calculations were performed to determine the optimum conditions for sulphate roasting, including air ratio, temperature, and oxygen enrichment. Experimental roasting of the ore at temperatures up to 650°C produced a calcine that was 91.2% soluble zinc after leaching. The results indicated that sulphate roasting is a viable process for extracting zinc from this carbonate ore.
Madkour 1986-journal of-chemical_technology_and_biotechnologyAl Baha University
Thermodynamic Studies on Sulphate Roasting for Zinc Electrowinning from Carbonate Ore
The bulk of the work consists of a theoretical study of the possibility of submitting Umm-Gheig carbonate ore to sulphate roasting. The use of the admixture with pyrites is to enable a carbonate ore to be treated in a similar way to a sulphide ore, and by doing so, to produce a roasted product capable of being treated by orthodox zinc electrowinning methods using sulphate solutions. Thermodynamic studies have been made to find the optimum conditions for sulphate roasting, in either normal air or enriched 36% oxygen air. The results obtained from the experimental work at different roasting temperatures in a tube furnace indicated that a maximum dissolu- tion of 91.2% Zn with a 17.9% Fe could be obtained at a roasting temperature of 650°C for 4 h, followed by leaching in 4% H2S04 (by vol.) at 60°C. The results of the electron microscopic investigation confirmed by metal value data given in the ASTM cards coincide well with results given by chemical analysis
Study of the Sulfur Trioxide Generation Mechanism and Control Method Using We...inventionjournals
In coal fired power plant, especially using sulfur content fossil fuels, much attention in recently paid to sulfur trioxide and sulfuric acid mist emission, because conventional desulfurization system should not be removed, which is installed to meet air quality standard for sulfur dioxide. Sulfur trioxide is highly reactive with water vapor and generally convert to sulfuric acid mist in atmosphere. Sulfuric acid is very fine under-submicron sized particulate matter or droplets. Recently sulfur trioxide cause air pollution and public health, discussion comes out, especially in the United States and Japan, that regulations and guideline should be enlarge the sulfur dioxide to sulfur trioxide and sulfuric acid. Moreover most countries reinforce sulfur oxides emission regulations or guidelines from coal-fired power plant. In this study, focusing that how to control the sulfur trioxide and sulfuric acid mist. Sulfuric acid mist found depending on the flue gas temperature. Generation and conversion rate of sulfur trioxide were measured according to temperature. The absorbent was selected to remove sulfur trioxide and sulfuric acid using wet type desulfurization system which the most proven technology at this moment.
The document summarizes research on producing activated carbon from date palm fronds through chemical activation using sodium hydroxide and phosphoric acid. The researchers evaluated how different activation parameters like temperature and chemical ratios affected the surface area and porosity of the activated carbons. Products activated with phosphoric acid had highly developed porosity, while those activated with sodium hydroxide or steam had moderate microporosity. The activated carbons were then tested for their ability to adsorb pollutants from water, showing potential for water treatment applications.
The document discusses various sorbents for removing mercury from flue gas. It describes several commercial sorbent systems, including Sorbalit which uses hydrated lime and sulfur-promoted activated carbon. Hydrated lime removes acid gases via chemical reactions, while activated carbon adsorbs mercury and organic pollutants through its porous structure and active sites. The GE-Mitsui-BF process uses activated coke to remove mercury, SOx, NOx, and other pollutants. Spent sorbents can be regenerated or treated to produce stable compounds for disposal.
Enhanced fluidized bed methanation over a Ni Al2O3 catalyst for production of...Pengcheng Li
This document summarizes a study that investigated the fluidization behavior and CO methanation performance of a Ni/Al2O3 catalyst in a fluidized bed reactor for producing synthetic natural gas. The researchers found that the pure Ni/Al2O3 catalyst failed to properly fluidize on its own due to particle sizes between 10 and 100 μm, but fluidization was improved by adding larger Al2O3 particles. Methanation performance in the fluidized bed reactor increased substantially with the Al2O3 addition. Temperature was found to control the methanation reaction mechanism, with surface reactions dominating at lower temperatures and external diffusion controlling at higher temperatures. Stability tests showed the fluidized bed reactor had higher CO conversion, methane selectivity
1) The Pt supported on mesoporous silicate FSM-16 showed high and stable catalytic activity for the hydrodesulfurization of thiophene at 350°C and this activity was higher than that of commercial CoMo/A120 3 catalysts.
2) Among noble metal/FSM-16 catalysts, Pt/FSM-16 showed the highest activity for the hydrodesulfurization of thiophene. The optimal loading of Pt on FSM-16 was determined to be 5 wt%.
3) The activity of Pt/FSM-16 decreased temporarily when hydrogen sulfide was introduced but was restored after cutting off the introduction, indicating that hydrogen sulfide is reversibly adsorbed on the Pt/FSM
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
The document summarizes a study on the simultaneous extraction of copper and iron from chalcopyrite concentrates in hydrochloric acid media using chlorine gas. The study investigated the effect of various parameters including acid concentration, temperature, sodium chloride addition, and time on the dissolution of copper and iron. Key findings include that copper and iron dissolution increased with acid concentration and temperature but decreased with the addition of sodium chloride. Dissolution was also found to increase over time. The best conditions for copper extraction were determined to be 333K temperature, 10% concentrate, and 1 hour leaching time.
Research Inventy: International Journal of Engineering and Scienceresearchinventy
This document summarizes a study on extracting copper and iron from chalcopyrite concentrates using hydrochloric acid and chlorine gas. The researchers investigated how factors like acid concentration, temperature, pulp density, sodium chloride addition, and chlorine gas flow rate affected the dissolution of copper. They found copper dissolution increased with higher acid concentration, temperatures from 318K to 333K, and lower pulp density. Sodium chloride addition also increased dissolution. With a 10% concentrate, 333K temperature, and 400mL/min chlorine gas, nearly 93% of copper was extracted within 1 hour. Characterization methods confirmed the leaching mechanism involved.
Effect of Solvent Swelling on the reactivity of demineralized Turkish LigniteIJERA Editor
In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.
This document describes a fixed bed vapor phase adsorptive desulfurization process for removing sulfur from naphtha (a type of fuel) using zeolite adsorbents. Metal ion exchanged zeolite Y adsorbents were found to selectively remove refractory organosulfur compounds from refinery naphtha. Under optimized conditions, around 54 mL of naphtha per gram of adsorbent could be treated, achieving a breakthrough sulfur concentration of 30 mg/L in the effluent with no loss of octane number. The adsorbents were fully regenerable by controlled oxidation at high temperature using diluted air, requiring no temperature swing between adsorption and regeneration cycles.
Effect of alumina support on the performance ofNan Wu
This document describes a study that investigated the effect of different alumina supports on the performance of Pt-Sn-K/γ-Al2O3 catalysts in isobutane dehydrogenation. Alumina supports were synthesized by hydrochloric acid reflux and ammonia precipitation methods. Pt-Sn-K/γ-Al2O3 catalysts were prepared using these different alumina supports. Testing found that the catalyst supported on alumina from ammonia precipitation had smaller Pt particle sizes, weaker acidity, higher activity, and better selectivity and stability for isobutene production compared to the catalyst supported on alumina from hydrochloric acid reflux.
This document discusses the major chemical paths for the combustion of hydrogen sulfide under conditions typical of the Claus furnace process. It identifies over 150 reactions that are involved and important issues such as the formation and destruction of COS and CS2. The mechanism can explain important phenomena in sulfur plant design like the formation of hydrogen. However, more kinetic and thermodynamic data are still needed for some reactions at high temperatures typical of Claus furnace conditions.
The document analyzes the effects of high-temperature pyrolysis between 1000°C-1600°C on the structure and properties of coal char and petroleum coke. Results showed that the carbon crystallite structure of both materials became more ordered with increasing temperature, though coal char's graphitization was lower. BET surface area, gasification reactivity, powder resistivity, and real density changed differently for coal char and petroleum coke with increasing pyrolysis temperature. The study provides insights into the differences between coal char and petroleum coke properties after high-temperature treatment to help substitute coal char for petroleum coke in producing carbon anodes.
The document discusses methods for determining the carbon, hydrogen, nitrogen, and sulfur content of coal through ultimate analysis. It describes the standard Kjeldahl method for determining nitrogen, which involves digesting coal samples in sulfuric acid and a catalyst then distilling and titrating the resulting ammonia. Corrections may need to be made to carbon, hydrogen, and sulfur values depending on the forms in which they occur in coal. Automated systems now allow simultaneous determination of multiple elements.
The document discusses optimizing parameters for microwave-assisted extractive/oxidative desulfurization of diesel fuel using an ionic liquid. It synthesized an acid Bronsted ionic liquid and used it with vanadyl acetylacetonate catalyst and hydrogen peroxide to remove sulfur from real Algerian diesel. A full factorial experiment was used to optimize the mass ratio of catalyst to oil, volume ratio of ionic liquid to oil, and reaction time. The maximum 81.77% desulfurization yield was achieved with a catalyst to oil ratio of 0.4%, ionic liquid to oil volume ratio of 11%, and a reaction time of 70 seconds under microwave radiation.
Nickel and cobalt transfigured natural clay: a green catalyst for low-tempera...Devika Laishram
Soot particulates in engine exhausts pose a severe threat to the environment and human health – causing cancer, affecting the heart and lungs and drives metal processes. This study proposes a practical,
real-world application of transition metal modified natural clay as an environmentally benign, low-cost,
green catalyst for soot oxidation. Ni and Co (NC-Clay) incorporated natural clay catalysts were prepared
by a simple wet impregnation method and meticulously characterized by different characterization
techniques. The catalyst exhibited higher H2 absorption at a lower temperature with similar trends as
observed in O2 TPD that indicated a remarkable redox property, which is useful for applications as a
catalyst in soot oxidation. Excellent catalytic activity with a very low T50 of 358 1C was observed and can
be accredited to the improved surface oxygen vacancies and thermal stability by the metal modification
of clay
This document summarizes a study investigating ultra-deep adsorptive desulfurization of diesel fuel over supported TiO2−CeO2 adsorbents. Key findings include:
1) Light irradiation of diesel fuel prior to adsorption treatment resulted in a 30-fold increase in desulfurization capacity compared to untreated fuel, achieving sulfur removal to below 1 ppmw.
2) Sulfur K-edge XANES analysis identified sulfones as the primary sulfur species on spent adsorbents, suggesting light irradiation chemically transforms original sulfur compounds.
3) Adsorption selectivity tests showed higher removal of indole and sulfones compared to thiophenes and poly
Similar to Disposition Pattern of Sulphur Functional Groups in High Sulphur Ledo Coals of Assam (20)
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
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Disposition Pattern of Sulphur Functional Groups in High Sulphur Ledo Coals of Assam
1. IOSR Journal of Applied Chemistry (IOSR-JAC)
e-ISSN: 2278-5736.Volume 4, Issue 3 (May. – Jun. 2013), PP 01-08
www.iosrjournals.org
www.iosrjournals.org 1 | Page
Disposition Pattern of Sulphur Functional Groups in High
Sulphur Ledo Coals of Assam
A.Kumar1
and S.K. Srivastava2
1.Department of Applied Chemistry, Theem College of Engineering, Mumbai University,India
2.Central Institute of Mining and Fuel Research, Digwadih Campus(erstwhile CFRI), P.O – FRI, Dhanbad-
828108, Jharkhand, India.
Abstract: Studies for determination of sulphur functional groups present in Ledo coal of Assam State of North
Eastern Region of India were carried out using Temperature Programmed Reduction (TPR) method. TPR
studies were carried out in presence of Resorcinol and hydrogen gas to arrive at the final result. TPR studies on
model sulphur compounds viz. L-Cysteine, synthetic rubber, Thiokol, having hydroxyl terminal groups,
thioplast, pyrite with sand, and Garlic were carried out in order to assign various sulphur functional groups
present in Ledo coal. Six numbers of hydrogen sulphide evolutions from Ledo coal were observed in the
temperature range of 190 – 2200
C, 260 – 2900
C, 360 - 3900
C, 460 – 4900
C, 510 – 5400
C and 590 – 6200
C
corresponding to mercaptan/ disulphide (0.30), Thiol (1.70), AromaticThioether (0.50), Thiophene (0.90), pyrite
+ part of complex thiophene (0.60), part of complex thiophene (0.30), The thioketonic sulphur in Ledo coal is
estimated to be 1.59 using controlled nitric acid oxidation experiments.
Keywords : Ledo coal, Assam coal, high sulphur coal, model sulphur compounds, TPR, desulphurization,
hydro desulphurization, disulphide, Thiol Thioether, Thiophene, Thioketone.
I. Introduction
India is blessed with very high ash coals. The only source of low ash coal is north eastern region of
India. But these coals have high sulphur content. In general it contains 3 to 6% sulphur out of which 75 – 90% is
in organic [1,2] form while rest is in inorganic form viz. sulphate sulphur and pyritic sulphur. Since pyritic
sulphur is highly disseminated in the organic matrix of coal, it can not be physically separated using specific
gravity principle. When these coals are chemically treated with oxidizing agents or reducing agents or auto
oxidized, the desulphurization does not occur quantitatively. The iron sulphate can be removed easily by
washing with water. The pyrite is converted into iron sulphate which is soluble in water. Physical separation
processes can not remove organic sulphur while Microbial method can remove only to a small extent of organic
sulphur but 90% pyrite removal with thiobascillus Ferro oxidans was observed.
It lead us to think that organic sulphur is present in these coals in more than one or two forms. Thus in
order to have effective chemical desulphurization of NE region coals of India and also to utilize high sulphur
assam coal as a blend (5-10%) for coke making in steel industry as well as thermal power stations with lesser
SO2 evolution, a knowledge of all the sulphur functional groups present in coal is a must. Temperature
Programmed Reduction method have been reported by Attar and Dupuis[3],Majchrowicz [4] in the past and
recently by E.Jorjani et al [5] for this purpose.Juntgen and Juntgen[6] and Van Heek [7]proposed a
thermokinetic method involving linear temperature time program for measuring the rate and amount of sulphur
evolution as a function of temperature for evaluating various sulphur functional groups .The capability for direct
speciation and approximate quantification (+10%) of organic sulphur forms has also been demonstrated using
XANES and XPS[8-11].XPS and XANES have also been used to establish the trend of increasing aromatic
sulphur content with increasing rank [12].These studies basically establish the potential connections between the
reactions of sulphur during coal metamorphism and laboratory pyrolysis as were examined by Kelemen [13]
while studying the thermal reactivity of sulphur forms in coal using XANES,TPD and XPS.Thus these suggests
that sulphur forms are transformed during the study by these methods and hence can not give an estimate of
sulphur functional group unambiguously.Moreover,a comparison of reductive method with X-ray based
instrumental techniques –XANES,XPS etc .reported by William H. Calkins[14] showed comparable trends in
organic sulphur forms in coal.However, complete assignment of sulphur functional group could not be done
owing to certain draw backs most importantly due to ambiguity about complete sulphur evolution from each
functional group in the form of H2S as found in the earlier work of Juntgen and Juntgen[6], VanHeek [7],
Dupuis[3],& Majchrowicz[4] and as per the work reported by Srivastava SK et al [15,16,17].
For assigning the sulphur functional groups in high sulphur coal, TPR studies- both on model sulphur
compounds and on Ledo coal was essential and have been done. Studies on optimization of reaction conditions
for total evolution of hydrogen sulphide from each and every sulphur functional groups is also a must in order to
remove ambiguity Thus the present paper is an attempt to fill the gap in the above mentioned studies carried by
2. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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earlier workers,and comprises of all the various studies mentioned above to know the distribution of sulphur (
mainly organic form).
II. Experimental
Temperature Programmed Reduction studies(TPR) on Ledo coal was carried out with X72 B.S.Mesh
sized coal particles.A glass/quartz tubular reactor was fabricated having I.D.;4.0 cms and height 16.5 cms. with
three openings at the top.Through the first opening hydrogen gas was passed continuously (which acted as a
flushing gas also) and through second opening a thermometre cap was inserted.The third opening was used as
outlet for gaseous products of reaction taking place inside the reactor along with residual hydrogen and it was
passed through a series of bubblers containing cadmium acetate solutionThe outlet of reactor was separated
from a series of bubblers by an ice cooled tar catch pot..The TPR study was carried out inside a tubular furnace
with 5.0 cms I.D. and 34 cms. height. The glass /quartz reactor with specified size of coal sample and resorcinol
was placed inside the reactor and thereafter controlled flow of hydrogen gas was switched on.For measurement
of the temperature of the reaction zone ,both thermometer (inside the reactor) and thermocouple ( outside the
reactor and inside the furnace) were used to monitor and cross check the temperature.Heating rate was
controlled through Sunvic energy regulator.
The coal and resorcinol(hydrogen-donating compound) mixture was heated in the aforementioned
reactor in the presence of hydrogen gas flowing very close to the reaction mixture at the rate of 70 m3
per
minute.The mixture was heated at 100
C per minute heating rate until evolution of H2S commenced at a particular
temperature and that point temperature was maintained constant until evolution of H2S gas ceased.This was
checked by passing the product gas to bubblers filled with cadmium acetate solution when no more yellow
precipitate of cadmium sulphide is obtained.After the first evolution of H2S was completed,the temperature was
further raised at the same rate until the second evolution of H2S started and later ceased as before.The gradual
heating and consequent evolution of H2S was continued until the temperature of 6200
C was reached.The H2S
evolved within different temperature ranges was absorbed in cadmium acetate solution to estimate sulphur
gravimetrically as yellow cadmium sulphide for each temperature range.The yellow cadmium sulphide was
filtered,washed with hot distilled water and dried in an air oven at 1100
C till constant weight.One blank filter
paper was also washed and dried in similar way in order to substract the weight of blank filter paper.
The coal particle size used was ~8,-212um.The Ledo coal was analysed for ash(A),moisture(M),volatile
matter(VM),fixed carbon (FC),C,H,N and oxygen contents,calorific value and sulphur distribution as per the
Bureau of Indian Standard methods specified in the literature.The total sulphur in the coal was determined using
a Leco model SC-132 (Leco Corporation,USA).These have been given in Table – I in on as received basis.
The determination of thioketonic sulphur has been given in our study “Estimation of thioketonic sulphur
in high sulphur assam coals by nitric acid oxidation. [18 ]
III. Results And Discussion
Table I summarises the data on Proximate and Ultimate analyses,calorific value and sulphur
distribution figures of Ledo coal on as received basis and Table II on dry mineral matter free (dmmf) basis.The
values on dmmf basis was calculated using the equation:
MM – 1.11A + 0.5Spyr + 2.5Ssulph.
Where MM = mineral matter , A = Ash , Spyr = Pyrite Sulphur and Ssulph. = Sulphate sulphur.
3.1 Approach Towards the Problem:
Coal desulphurization involves cleavage of carbon-sulphur ( C-S ) bonds present in coal and taking out
the sulphur mainly as H2S/SO2.If sulphur is present in coal in more than one form then depending, upon the
sulphur functionality and the environment of the C-S bond,the strength of the different C – S bonds would
vary.if the coal is heated at a certain rate,the weakest C-S bond would break first and the strongest C-S bond
would break last.If the sulphur is taken out as H2S and is quantified at each level of evolution,the number of
sulphur functionalities along with their quantitative values can be determined.By using model sulphur
compounds (some of which are polymeric in nature), containing known sulphur functionalities in TPR
studies,comparison of the results of sulphur evolution with that obtained from coal would identify sulphur
functional group present in coal matrix.While assigning the sulphur functionalities present in coal it should be
borne in mind that above 3000
C temp.,several pyrolytic reactions occur and one form of the sulphur
functionality may change to another resulting in different temperature of H2S evolution.Thus our approach
involves the immediate and continuous flushing out of H2S formed as soon as it is formed in the TPR study.
3.2 Temperature Progammed Reduction studies on Model sulphur compounds
Model sulphur compounds e.g,synthetic rubber, Thiokol, Thianthrene, Dibenzothiophene, Thioplast
,Cysteine , Pyrite and garlic were mixed with resorcinol thoroughly and TPR studies were carried out under
3. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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optimum reaction condition i.e.100
C/minute rate of heating and 70m3
flow of hydrogen.H2S gas was evolved at
different temperature ranges.The same has been presented in Table- III for different model sulphur compounds
along with the assignment of sulphur functional groups .
3.3 Assignment of Various Sulphur Functionalities Present in Ledo coal:
An attempt has been made in the present paper to correlate the various sulphur evolution from Ledo
coal to different organic sulphur forms based on temperature programmed reduction studies of model organic
sulphur compounds under exactly similar reaction conditions to that of coal in addition to the facts obtained
from literature-which corroborates the assignment made.
TPR studies on the model organic sulphur compounds gave a clear cut temperature range at which H2S
evolution took place corresponding to different functionalities.However, these evolutions cannot match
exactly with those evolving from coal for different steric, electronic environmental (around C-S bond)
reasons.Considering the structural complexity of coal , H2S evolution will take place at slightly different
temperatures than the above stated evolutions for model sulphur compounds.
During the formation of Assam coals,sulphur has probably interchanged with oxygen atom owing to
the presence of microorganism thiobascillus ferro oxidans ,and also considering the marine bed present in the
area in the past,sulphur is also present in Heteroatomic rings as well as in linking units[18] In Assam coal.”O”
containing functional groups normally present in coal are –COOH, -OH, >C=O, and –O_
, hence by replacing
„O‟ atom by „S‟, the following forms of sulphur would be present in assam coals and it is true for Ledo coal as
well:
C=O , C=S , C=S , SH , >C=S , -S-
SH SH OH
These sulphur groups would react in presence of hydrogen to give H2S corresponding to different C-S bond
strengths at different temperature ranges.
(g) >C=S form,if present would react with aliphatic chains present in the coal under pyrolytic conditions to
present condensed thiophenic form which is very difficult to break small amounts of H2S may come out above
5000
C.
Thus,keping in view of the above facts the assignments made for Ledo coal are provided In Table-V.
IR spectra of Ledo coal has been given in fig.I,II,III,IV for four different conditions of Ledo coal.
Coal-viz. (i) Raw Ledo(ii)Ledo coal treated upto 2200
C in presence of resorcinol (iii ) Residue coal
treated upto 6200
in presence of resorcinol (iv) Nitric acid treated coal for thioketonic sulphur determination.
The IR spectra of raw coal gives a broad absorption band at 3440 cm−1in the coal, which appears to be mainly
due to N–H and O–H groups. The peaks for O–H groups at 3600–3800 cm−1appear to be for those associated
with clay minerals. The aromatic hydrogen band at 3040 cm−1is absent in the coal indicating its highly
substituted and condensed nature. The peak at 2920 cm−1and 2850 cm−1appearing as sharp peaks of medium
intensity, may be assigned to aliphatic and alicyclic CH3, CH2 and CH groups although the major contribution
is expected to be due to CH2 groups. The intensity of peak at 2920 cm−1is greater than the peak 2850
cm−1indicating the presence of long aliphatic chains in the coal. The peak at 1699 cm−1appears to indicate the
presence of carbonyl (C=O) content. The peak around 1600 cm−1in the coal is observed due to aromatic C=C,
vinylic C=C and possibly due to other O-containing functional groups. The oxygen containing functional groups
found in coal specifically include phenols and alcohols, ethers, carboxylic acid and carbonyls. In view of the
diversity of decomposed plant matter, finding any systematic variation in the distribution of these functional
groups in coal seems unlikely. Several authors have reviewed quantitative determination of these various
oxygen functional groups.A strong band at 1436 cm−1in the coal was observed. This is mainly due to CH3
asymmetric deformation and CH2 group in bridges but may also be partly due to aromatic C=C and strongly
hydrogen bonded O–H groups. The band at 1372 cm−1is mainly due to CH3 symmetric deformation while –
CH3 and –CH2 in cyclic structures may also partly contribute to this band.Intensity of this peak is much lower
than the peak at 1436 cm−1indicating that the methylene as long side chains. The band between 880 cm−1and
750 cm−1has been assigned to aromatic structures.The weak band at 690 cm−1observed in the coal could
possibly be due to C–S bond. These absorptions are most useful in determining the aromatic ring structure of a
coal.Vibrational IR frequency is also observed at 485 cm-1
in the coal suggesting the presence of disulphide i.e.,
-S-S- group [19].No substantial information on organic sulphur functionalities is obtained from the IR spectra of
(i) raw Ledo coal and that from (ii) Ledo coal treated upto 2200
C in presence of resorcinol (iii ) Residue coal
treated upto 6200
in presence of resorcinol.On comparison of IR spectra of the raw Ledo coal with that of nitric
acid treated coal,it is observed that the number of –COOH functional groups have enhanced in the nitric acid
treated coal as a result of oxidation.It is further substantiated by the presence of overlapping C-H (str.) band,(i)
1705-1720 cm-1
for C=O of acid ,& (iii) 1540 cm-1
for C-O-H bending ,which is slightly upshift ,in
4. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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addition,there is a characteristic spectral band at1340-1345 cm-1
which is very very weak and seems like noise
and hence can not substantiate the presence of S=O group from sulphonic acid and sulphones in the IR spectra
of nitric acid treated coal.There are no bands in the range 2800-2900 cm-1
corresponding to alicyclic
CH3,CH2,CH groups in nitric acid treated coal. This is perhaps due to destruction of coal moiety due to acid
oxidation. It can be observed from the values given in the Table-V that some amount of sulphur is still left in the
residual coal which is probably due to thioketonic (>C=S)form of sulphur which has converted into condensed
thiophene, within the structure of coal under pyrolytic conditions and which is very difficult to break in order to
evolve as H2S. The IR spectra of the raw coal has spectral bands in the region 1050-1100 cm-1
supports the
presence of C=S functional group Hence this form of sulphur has been estimated as thioketonic sulphur.
TABLE - I
CHARECTERISATION OF LEDO COAL
(ON AS RECEIVED BASIS)
TABLE-II
CHARECTERISATION OF LEDO COAL
ON DRY MINERAL MATTER FREE BASIS
1. Proximate Analysis ( % )
Volatile Matter 45.0
Fixed Carbon 55.0
2. Ultimate Analysis ( % )
C 78.50
H 5.90
N 1.30
S 6.60
O (by difference) 7.70
MM = 1.11A + 0.5 Spyr + 2.5 SSulphate
TABLE - III
TPR STUDY ON MODEL SULPHUR COMPOUNDS
Model Compounds Temp. Ranges of
H2S evolution
„S‟ Functional Group
Present
Synthetic Rubber 210 – 2200
C Disulphide
360 – 3700
C Sulphide
Thiokol 220 – 2400
C Polysulphide
310 – 3300
C Thiol
410 – 4300
C Thioether
520 – 5300
C Thiophene
600- 6200
C Condensed Thiophene
Thianthrene 360 – 3900
C Aromatic Sulphide
Dibenzothiophene 480 – 4900
C Thiophenic Sulphur
Thioplast 260 – 2700
C Thiol
Cysteine 210 – 2200
C Mercaptan
Pyrite 530 – 5400
C Pyrite
Garlic ( Dried) Approx. same as Thiokol * same as fromThiokol #
*Garlic contains allicin and when allicin degrades it produces various diallyl sulphides, the most common of
which is diallyl dishulphide:Allicin degrades very easily when temp. increases or garlic is crushed.The
similarity in H2S evolutions for both Thiokol and garlic is mainly due to similarity in poly sulphide structure. #
Given in table no.III for Thiokol polymer.
1. Proximate Analysis ( % )
Ash 18.2
Moisture 3.3
Volatile Matter 35.3
Fixed Carbon 43.2
2. Calorific Value ( K Cal/ Kg ) 5950
3. Ultimate Analysis ( % )
C 59.06
H 4.44
N 0.97
S 6.10
O (by difference) 7.93
4. Sulphur Distribution (% )
Pyritic 0.76
Sulphate 0.35
Organic 4.99
Total „S‟ 6.10
5. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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Structure of Diallyl Disulphide
Structure of Thiokol [ CH2- CH2-S-S- CH2- CH2 ]
TABLE – IV
ESTIMATION OF THIO-KETONIC SULPHUR
TABLE – V
SULPHUR EVOLUTIONS AT DIFFERENT TEMPERATURE RANGES FROM LEDO COAL AND
ASSIGNMENT OF SULPHUR FUNCTIONAL GROUPS.
Temp. Range ( 0
C ) Sulphur Evolved ( % ) Sulphur Functionality Assigned
190-220 0.30 Mercaptan/ Disulphide
260-290 1.70 Thiol
360-390 0.50 Aromatic sulphide
460-490 0.90 Simple Thiophene
510-540 0.60 Pyritic + Part of complex thiophene
590-620 0.30 Part of complex thiophene
TABLE-VI
COMPLETE ASSIGNMENT OF SULPHUR FUNCTIONAL GROUPS PRESENT IN LEDO COAL.
Temperature
Range Code
I II III IV V V VI
Sulphur
Functionality
Mercapta
n
Disulphide/Thi
ol
Thio-Ether Thiophene Pyrite Sulph
-ate
Thio-
Ketone
Coal Sample
Ledo Coal 0.30 1.70 0.50 0.90 0.76 0.35 1.59
Fig-I IR spectra of raw Ledo coal
Sulphur Value Heads % „S‟ in Ledo Coal
( before and after estimation )
Total Sulphur in Original Coal ( A) 6.10
Total Sulphur in Oxidised Coal ( B) 3.20
Pyritic + Sulphate Sulphur in Original Coal (C) 1.10
(A) – ( B ) – ( C ) i.e., Thio- Ketonic Sulphur 1.80
6. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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Fig-II IR spectra of Ledo coal treated upto 2200
C in presence of resorcinol
Fig-III IR spectra of Ledo coal treated (TPR) upto 6200
C in presence of resorcinol
7. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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Fig-IV IR spectra of nitric acid treated Ledo coal
IV. Conclusion and Summary :
A systematic optimization study usingTemperature programmed reduction study along with nitric acid
oxidation on Ledo coal has been carried out .After carrying out TPR study on model sulphur compounds it was
found that hydrogen sulphide evolutions in the temperature ranges 190-220, 260-290,, 360-390, 460-490, 510-
540, 590-6200
C are due to mercaptan, disulphide/thiol, thioether, thiophene, pyrite and complex thiophene
groupsThe thioketonic group is also present as determined from nitric acid oxidation.IR studies showed that
resorcinol was not destroyed up to 3000
C.On heating coal upto 6000
C,the various functional groups present in
coal are devolatilised and on nitric acid treatment, the coal was oxidized leading to enhancement in –COOH
functional group.Thus based on above studies,it was concluded that sulphur present in Ledo coal are in the
forms: mercaptan, disulphide/thiol, thioether, thiophene, pyrite, sulphate and thioketone .These forms
are shown in Table VI.
Thus TPR study in combination with nitric acid oxidation can effectively be used for determining the
organic sulphur functional groups in any high sulphur coal of the world.The data generated would enable
chemical methods of desulphurization to be selected/devised and also prior knowledge of the extent to which
coal can be desulphurised.
Acknowledgement:
Thanks are due to the Department of Coal, Government of India for providing us financial support for
this project.One of the author is also thankful to the Director and the Principal Theem College of Engineering
for their constant encouragement.
8. Disposition Pattern Of Sulphur Functional Groups In High Sulphur Ledo Coals Of Assam
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