- The document describes models developed for a fluid catalytic cracking fluidized bed reactor using a four-lump kinetic scheme.
- The reactor is modeled as a two-phase system consisting of a bubble phase modeled as plug flow and an emulsion phase modeled as continuous stirred-tank reactor.
- Kinetic rate equations are provided for the cracking of gas oil to gasoline, light gases, and coke based on the four-lump scheme. Mass balance equations are developed for each phase and solved numerically.
This 3 sentence summary provides the key details from the document:
The document describes an analytic model for pressurization and cryogenic propellant conditions in liquid rocket tanks. The model divides tanks into 5 nodes and solves conservation equations of mass and energy across the nodes. It can model various mass transfer mechanisms and has been validated against test data. The model provides tank conditions like pressure and temperatures over mission durations for design and analysis of cryogenic rocket stages.
An insight into spray pulsed reactor through mathematical modeling of catalyt...Siluvai Antony Praveen
This document presents a mathematical model developed to study the impact of nozzle-catalyst distance and bulk gas temperature on the conversion and hydrogen evolution rate in a spray pulse reactor for the catalytic dehydrogenation of cyclohexane. The model was able to predict the effects of reactor configuration and operating parameters on conversion and evolution rate with over 90% accuracy. Reactor optimization analysis identified an optimal design of 5 cm nozzle-catalyst distance and 50°C bulk gas temperature, which was predicted to increase conversion from approximately 32% to 74%. The model provides a means to design endothermic heterogeneous catalytic reactions in spray pulse reactors.
Slurry reactor Presentation Chemical Engineering CL311gptshubham
This document describes a slurry reactor. A slurry reactor is a multiphase reactor where a gas is bubbled through a liquid containing suspended solid catalyst particles. The document defines slurry reactors, provides examples of their applications, and discusses modeling and design considerations. Equations are presented for determining the rate of gas absorption, transport to the catalyst surface, diffusion and reaction within catalyst pellets, and identifying the limiting step. Advantages and disadvantages of slurry reactors are also summarized.
NASA has developed cryogenic fluid management technologies to support future exploration missions. Recent accomplishments include validating computational models against past cryogenic storage experiments, demonstrating long term liquid hydrogen storage with minimal boil-off, and testing a radio frequency mass gauge that accurately measured propellant levels in liquid hydrogen. Future work will focus on technologies for storing and transferring cryogens in low gravity environments to support propulsion and surface systems, with the goals of reducing launch mass and simplifying vehicle operations for missions to the Moon and Mars.
This document discusses reactor design for multiple reactions. It describes types of reactors including batch, semi-batch, plug flow, and continuous stirred-tank reactors (CSTRs). It also covers parameters for reactor design like volume, flow rate, concentrations, kinetics, temperature, and pressure. The document discusses plug flow versus CSTR design and designing for parallel, series, and complex reaction networks. It provides methods for maximizing desired products in multiple reaction systems, including adjusting conditions, choosing proper contacting patterns and reactors, and optimizing space-time or residence time. The document also presents equations for modeling multiple reactions occurring in a CSTR.
This document discusses multiphase reactors, which involve gas, liquid, and solid phases. It covers the construction, classification, examples, design considerations, kinetics, advantages, and applications of these reactors. Specifically, it examines slurry bubble column reactors and slurry stirred tank reactors. It provides examples of industrial processes using multiphase reactors like hydrogenation, polymerization, and Fischer-Tropsch synthesis. Rate equations are also presented to model reactions in these complex systems.
This document discusses reactor design and chemical kinetics. It begins by describing ideal and real reactor types, including plug flow reactors and continuous stirred-tank reactors. It then discusses factors that influence reactor cost such as vessel material and size. The document also covers kinetic models for CSTR and PFR reactors and how they are used to determine reactor size and dynamics. It discusses various effects of temperature on kinetics and equilibrium in reactors. Finally, it provides an overview of how simulators can be used to model different reactor types and reactions.
Modeling of Propellant Tank PressurizationAmr Darwish
This document describes the modeling of propellant tank pressurization for hybrid rockets. The major advantage of modeling tank pressurization is that it is essential for predicting rocket performance, especially for hybrid rockets that use self-pressurizing oxidizers where thrust depends on tank pressure. The objective is to develop a model that can be incorporated into rocket design programs. The model assumes the propellant is a real gas, two-phase homogeneous mixture and analyzes governing equations using the Soave-Benedict-Webb Rubin and Peng-Robinson equations of state. Results show good agreement between measured and predicted ullage pressures and mass variations over time, validating the model.
This 3 sentence summary provides the key details from the document:
The document describes an analytic model for pressurization and cryogenic propellant conditions in liquid rocket tanks. The model divides tanks into 5 nodes and solves conservation equations of mass and energy across the nodes. It can model various mass transfer mechanisms and has been validated against test data. The model provides tank conditions like pressure and temperatures over mission durations for design and analysis of cryogenic rocket stages.
An insight into spray pulsed reactor through mathematical modeling of catalyt...Siluvai Antony Praveen
This document presents a mathematical model developed to study the impact of nozzle-catalyst distance and bulk gas temperature on the conversion and hydrogen evolution rate in a spray pulse reactor for the catalytic dehydrogenation of cyclohexane. The model was able to predict the effects of reactor configuration and operating parameters on conversion and evolution rate with over 90% accuracy. Reactor optimization analysis identified an optimal design of 5 cm nozzle-catalyst distance and 50°C bulk gas temperature, which was predicted to increase conversion from approximately 32% to 74%. The model provides a means to design endothermic heterogeneous catalytic reactions in spray pulse reactors.
Slurry reactor Presentation Chemical Engineering CL311gptshubham
This document describes a slurry reactor. A slurry reactor is a multiphase reactor where a gas is bubbled through a liquid containing suspended solid catalyst particles. The document defines slurry reactors, provides examples of their applications, and discusses modeling and design considerations. Equations are presented for determining the rate of gas absorption, transport to the catalyst surface, diffusion and reaction within catalyst pellets, and identifying the limiting step. Advantages and disadvantages of slurry reactors are also summarized.
NASA has developed cryogenic fluid management technologies to support future exploration missions. Recent accomplishments include validating computational models against past cryogenic storage experiments, demonstrating long term liquid hydrogen storage with minimal boil-off, and testing a radio frequency mass gauge that accurately measured propellant levels in liquid hydrogen. Future work will focus on technologies for storing and transferring cryogens in low gravity environments to support propulsion and surface systems, with the goals of reducing launch mass and simplifying vehicle operations for missions to the Moon and Mars.
This document discusses reactor design for multiple reactions. It describes types of reactors including batch, semi-batch, plug flow, and continuous stirred-tank reactors (CSTRs). It also covers parameters for reactor design like volume, flow rate, concentrations, kinetics, temperature, and pressure. The document discusses plug flow versus CSTR design and designing for parallel, series, and complex reaction networks. It provides methods for maximizing desired products in multiple reaction systems, including adjusting conditions, choosing proper contacting patterns and reactors, and optimizing space-time or residence time. The document also presents equations for modeling multiple reactions occurring in a CSTR.
This document discusses multiphase reactors, which involve gas, liquid, and solid phases. It covers the construction, classification, examples, design considerations, kinetics, advantages, and applications of these reactors. Specifically, it examines slurry bubble column reactors and slurry stirred tank reactors. It provides examples of industrial processes using multiphase reactors like hydrogenation, polymerization, and Fischer-Tropsch synthesis. Rate equations are also presented to model reactions in these complex systems.
This document discusses reactor design and chemical kinetics. It begins by describing ideal and real reactor types, including plug flow reactors and continuous stirred-tank reactors. It then discusses factors that influence reactor cost such as vessel material and size. The document also covers kinetic models for CSTR and PFR reactors and how they are used to determine reactor size and dynamics. It discusses various effects of temperature on kinetics and equilibrium in reactors. Finally, it provides an overview of how simulators can be used to model different reactor types and reactions.
Modeling of Propellant Tank PressurizationAmr Darwish
This document describes the modeling of propellant tank pressurization for hybrid rockets. The major advantage of modeling tank pressurization is that it is essential for predicting rocket performance, especially for hybrid rockets that use self-pressurizing oxidizers where thrust depends on tank pressure. The objective is to develop a model that can be incorporated into rocket design programs. The model assumes the propellant is a real gas, two-phase homogeneous mixture and analyzes governing equations using the Soave-Benedict-Webb Rubin and Peng-Robinson equations of state. Results show good agreement between measured and predicted ullage pressures and mass variations over time, validating the model.
In this Course we get two sections:
Section 1
Introduction and information on the existing reactors
Visual images of reactors
Importance of Reactor Design
Section 2
- The General Mole Balance Equation
- The concept of Generation
- The Accumulation term
- The Design Equations for a Batch Reactor
- The Design Equations for a Continuous Stirred Tank Reactor
- The Design Equations for a Plug Flow Reactor
- The Design Equations for a Packed Bed Reactor
By the end of this block you should be able to differentiate between batch reactors vs. continuous flow reactors.
You should be familiar with the General Mole Balance Equation and how to apply it to every reactor.
You should know or at least get to know the Mole Balance Equations or Design Equations of each reactor in the Course.
This document discusses the classification and selection of chemical reactors. It outlines the basic types of reactors including batch, continuous stirred-tank (CSTR), and plug flow reactors (PFR). Selection of reactors depends on factors such as the process type (batch, continuous, catalytic), phase (gas, liquid, solid), and required mass and heat transfer rates. For example, batch reactors are used for small batch production while CSTRs are common for liquid reactions requiring mixing. PFRs provide higher efficiency and are used when significant heat transfer is needed. Selection also considers whether the reaction involves single or multiple steps.
This document discusses reactor design for single chemical reactions. It compares the size and performance of batch, mixed flow, and plug flow reactors. For single reactions where product distribution is fixed, plug flow reactors generally require less volume than mixed flow reactors to achieve the same conversion. The size ratio of mixed to plug flow reactors depends on the reaction order and conversion level. Connecting reactors in series improves performance by making the flow more plug-like.
DEVELOPMENT OF PARAFFIN BASED FUEL FOR HYBRID ROCKET MOTORJHUMKI NANDY
This project main finding was the high regression rate of paraffin with adding stearic acid, LDPE, EVA, carbon black, araldite and hardener. Regression rate was for three samples between 5-6mm/sec
This experiment involves conducting a saponification reaction between sodium hydroxide (NaOH) and ethyl acetate (Et(Ac)) in a continuous stirred tank reactor (CSTR) to determine the effect of residence time on conversion. A calibration curve will be prepared to relate conductivity measurements to conversion values for the 0.1M NaOH and 0.1M Et(Ac) reaction. The objectives are to determine conversion, the reaction rate constant, and the effect of residence time on conversion.
This document discusses reactor design for multiple reactions. It begins by describing types of reactors including batch, semi-batch, and continuous. Design parameters like volume, flow rate, concentrations, kinetics, temperature, and pressure are discussed for reactor selection. Equations for mixed flow and plug flow reactor design are presented. Plug flow reactors are generally smaller than continuous stirred tank reactors (CSTRs) for a given conversion. Methods for maximizing the desired product in parallel and series reactions include adjusting conditions like concentrations, temperatures, and choosing the proper reactor type. Multiple reactor systems with reactors in series or mixed flow reactors of different sizes can be used for high conversions that a single reactor cannot achieve.
This document discusses potential improvements in methanol synthesis. It summarizes recent research on clarifying the chemistry of methanol synthesis, studying mass transfer limitations, and investigating catalyst deactivation and regeneration. Regarding the chemistry, experiments showed methanol synthesis proceeds primarily via CO2 hydrogenation. Mass transfer experiments in a slurry reactor characterized the effects of temperature, pressure, impeller speed and other variables on the overall gas-liquid mass transfer coefficient. Further improvements may come from developing catalyst regeneration processes and understanding all factors affecting catalyst life.
Naphtha catalytic reforming process is the key process in oil refining to meet the demands of gasoline fuel specifications and hydrogen gas for hydrotreating and isomerization units. But one bottleneck of high aromatics content in gasoline may restrict the naphtha reforming process due to strict environmental regulations.
1) Conversion and reactor sizing for different reactor types such as batch, CSTR, PFR and reactors in series are discussed. Key equations for calculating conversion and sizing reactors given reaction rate data are presented.
2) Examples are provided to calculate the volume of a CSTR and PFR needed to achieve 80% conversion of a reactant based on rate data, and to compare the required volumes between reactor types.
3) For an isothermal reaction, a CSTR typically requires a larger volume than a PFR to achieve the same conversion due to operating at the lowest reaction rate throughout the reactor.
The document discusses several types of chemical reactors, including recycle reactors, autocatalytic reactors, and considerations for optimizing reactor performance and operating conditions. It addresses recycle stream ratios, performance equations, temperature progression, and non-ideal flow concepts such as residence time distribution, states of aggregation, and mixing effects.
This document discusses different types of chemical reactors, including plug flow reactors and continuous stirred tank reactors (CSTR). It provides information on their design considerations, advantages, disadvantages, and equations. Plug flow reactors allow minimal back mixing and each particle has the same residence time. CSTRs ensure proper mixing through the use of an impeller and assume perfect mixing. The document also provides examples of design equations for ideal reactors and discusses factors to consider for reactor selection like yield, cost, and safety.
Dynamic modeling and simulation of catalyticJhonatan Soto
This document summarizes a study on dynamic modeling and simulation of catalytic naphtha reforming. The dynamic model developed includes reaction kinetics, heat exchanger models, and furnace models. Kinetic modeling of the fixed bed reactors connected in series forms the core of the simulation. Reaction rates are represented using Hougen-Watson Langmuir-Hinshelwood expressions. Simulation results using MATLAB show fair agreement with plant data. The model can capture major dynamics in the reforming process system.
1) A compact fast pyrolysis reactor with Auger-type modules was tested for continuous liquid biofuel production from biomass.
2) Analysis of the produced pyrolysis oil showed that it took approximately 10 hours for the oil to fully condense when operating the reactor at a feedstock rate of 25 kg/h. Faster feedstock rates decreased the condensation time.
3) After 10 hours of operation, the pyrolysis oil properties remained stable, indicating steady performance of the reactor. The oil had physical and chemical properties typical of wood pyrolysis oils and a heating value of approximately 20 MJ/kg.
Effect of Operating Conditions on CSTR performance: an Experimental StudyIJERA Editor
In this work, Saponification reaction of ethyl acetate by sodium hydroxide is studied experimentally in a continuous stirred tank reactor at 1 atmospheric pressure. The aim of this study is to investigate the influence of operating conditions on the conversion and specific rate constant. The parameters considered for analysis are temperature, feed flow rate, residence time, volume of reactor and stirrer rate. The steady state conversion of 0.45 achieved after a period of 30 minutes. Conversion decreases with increase of reactant flow rate due to decrease of residence time. The stirrer rate has a positive effect on the conversion and rate constant. Specific rate constant and conversion increase with temperature within the studied temperature range. Within the range of reactor volume selected for analysis, conversion increases with increase in reactor volume. The results obtained in this study may be helpful in maximizing the conversion of ethyl acetate saponification reaction at industrial scale in a CSTR.
This document provides an overview of different types of reactors used in wastewater treatment processes. It defines reactors as vessels that hold wastewater for treatment and describes common reactor shapes. It then classifies and describes several reactor types including continuously stirred tank reactors, plug flow reactors, completely mixed batch reactors, fluidized bed reactors, packed bed reactors, and sequencing batch reactors. For each reactor type, diagrams are provided and equations are derived for hydraulic retention time and effluent concentrations based on reaction kinetics. Examples are also included to illustrate reactor sizing calculations.
Chato lox tank helium removal for propellant scavenging presentation 2009David Chato
System studies have shown a significant advantage to reusing the hydrogen and oxygen left in
these tanks after landing on the Moon in fuel cells to generate power and water for surface
systems. However in the current lander concepts, the helium used to pressurize the oxygen tank
can substantially degrade fuel cell power and water output by covering the reacting surface with
inert gas. This presentation documents an experimental investigation of methods to remove the
helium pressurant while minimizing the amount of the oxygen lost. This investigation
demonstrated that significant quantities of Helium (>90% mole fraction) remain in the tank after
draining. Although a single vent cycle reduced the helium quantity, large amounts of helium
remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to
reduce the helium to small (<0.2%) quantities. Two vent cycles may be sufficient since once the
tank has been brought up to pressure after the second vent cycle the helium concentration has
been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to
diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be
evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent
cycle is not required).
These slides may be used for a part of Advanced level course in Chemical Reaction Engineering. I taught this course to Masters level students covering 1.5 credit hours.
This document provides an overview of a Polymer Reaction Engineering course. The course goals are to introduce students to reaction engineering, polymerization reactions, kinetics, and reactor design. The course objectives are for students to understand reaction kinetics and apply this to the conceptual design of reactors. The schedule outlines 16 weeks of topics like batch and continuous reactor design, polymerization reactions, and a final design project.
This document discusses control of polymerization reactors. It outlines several key control problems including controlling reaction rates and temperature, monomer conversion and production rates, molecular weight and distribution, copolymer composition, and particle size and distribution. It then discusses various measurement techniques used for monitoring these properties, including viscosity, composition, surface tension, molecular weight distribution, and particle size distribution. Control is achieved through manipulation of parameters like temperature, feed rates, catalysts, and chain transfer agents.
1) Fluid catalytic cracking (FCC) is a process that uses a catalyst to crack large hydrocarbon molecules in gas oils and residual stocks into smaller molecules to produce lighter products like gasoline.
2) The FCC process involves circulating hot catalyst between a reactor and regenerator. In the reactor, the catalyst cracks the large molecules into smaller ones like gasoline. Coke deposits on the catalyst and is burned off to reheat the catalyst in the regenerator.
3) FCC units produce additional gasoline from heavier fractions of crude oil to correct the imbalance between market demand for gasoline and excess heavy products from distillation. FCC is a critical process in many refineries.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document describes a computational fluid dynamics (CFD) study of methane decomposition into hydrogen and solid carbon in a packed bed fluid catalytic cracking (FCC) reactor. The study used CFD modeling in COMSOL Multiphysics to simulate the decomposition reaction over time in the packed bed reactor. Results showed that increasing the reaction time from 0 to 1000 seconds increased the production of hydrogen from 0 to 42 mol/dm3 and carbon from 0 to 21 mol/dm3, while decreasing methane concentration from 50 to 29 mol/dm3, indicating that decomposition was occurring. Spatial profiles of velocity, concentration, pressure and permeability within the reactor were also determined and discussed.
In this Course we get two sections:
Section 1
Introduction and information on the existing reactors
Visual images of reactors
Importance of Reactor Design
Section 2
- The General Mole Balance Equation
- The concept of Generation
- The Accumulation term
- The Design Equations for a Batch Reactor
- The Design Equations for a Continuous Stirred Tank Reactor
- The Design Equations for a Plug Flow Reactor
- The Design Equations for a Packed Bed Reactor
By the end of this block you should be able to differentiate between batch reactors vs. continuous flow reactors.
You should be familiar with the General Mole Balance Equation and how to apply it to every reactor.
You should know or at least get to know the Mole Balance Equations or Design Equations of each reactor in the Course.
This document discusses the classification and selection of chemical reactors. It outlines the basic types of reactors including batch, continuous stirred-tank (CSTR), and plug flow reactors (PFR). Selection of reactors depends on factors such as the process type (batch, continuous, catalytic), phase (gas, liquid, solid), and required mass and heat transfer rates. For example, batch reactors are used for small batch production while CSTRs are common for liquid reactions requiring mixing. PFRs provide higher efficiency and are used when significant heat transfer is needed. Selection also considers whether the reaction involves single or multiple steps.
This document discusses reactor design for single chemical reactions. It compares the size and performance of batch, mixed flow, and plug flow reactors. For single reactions where product distribution is fixed, plug flow reactors generally require less volume than mixed flow reactors to achieve the same conversion. The size ratio of mixed to plug flow reactors depends on the reaction order and conversion level. Connecting reactors in series improves performance by making the flow more plug-like.
DEVELOPMENT OF PARAFFIN BASED FUEL FOR HYBRID ROCKET MOTORJHUMKI NANDY
This project main finding was the high regression rate of paraffin with adding stearic acid, LDPE, EVA, carbon black, araldite and hardener. Regression rate was for three samples between 5-6mm/sec
This experiment involves conducting a saponification reaction between sodium hydroxide (NaOH) and ethyl acetate (Et(Ac)) in a continuous stirred tank reactor (CSTR) to determine the effect of residence time on conversion. A calibration curve will be prepared to relate conductivity measurements to conversion values for the 0.1M NaOH and 0.1M Et(Ac) reaction. The objectives are to determine conversion, the reaction rate constant, and the effect of residence time on conversion.
This document discusses reactor design for multiple reactions. It begins by describing types of reactors including batch, semi-batch, and continuous. Design parameters like volume, flow rate, concentrations, kinetics, temperature, and pressure are discussed for reactor selection. Equations for mixed flow and plug flow reactor design are presented. Plug flow reactors are generally smaller than continuous stirred tank reactors (CSTRs) for a given conversion. Methods for maximizing the desired product in parallel and series reactions include adjusting conditions like concentrations, temperatures, and choosing the proper reactor type. Multiple reactor systems with reactors in series or mixed flow reactors of different sizes can be used for high conversions that a single reactor cannot achieve.
This document discusses potential improvements in methanol synthesis. It summarizes recent research on clarifying the chemistry of methanol synthesis, studying mass transfer limitations, and investigating catalyst deactivation and regeneration. Regarding the chemistry, experiments showed methanol synthesis proceeds primarily via CO2 hydrogenation. Mass transfer experiments in a slurry reactor characterized the effects of temperature, pressure, impeller speed and other variables on the overall gas-liquid mass transfer coefficient. Further improvements may come from developing catalyst regeneration processes and understanding all factors affecting catalyst life.
Naphtha catalytic reforming process is the key process in oil refining to meet the demands of gasoline fuel specifications and hydrogen gas for hydrotreating and isomerization units. But one bottleneck of high aromatics content in gasoline may restrict the naphtha reforming process due to strict environmental regulations.
1) Conversion and reactor sizing for different reactor types such as batch, CSTR, PFR and reactors in series are discussed. Key equations for calculating conversion and sizing reactors given reaction rate data are presented.
2) Examples are provided to calculate the volume of a CSTR and PFR needed to achieve 80% conversion of a reactant based on rate data, and to compare the required volumes between reactor types.
3) For an isothermal reaction, a CSTR typically requires a larger volume than a PFR to achieve the same conversion due to operating at the lowest reaction rate throughout the reactor.
The document discusses several types of chemical reactors, including recycle reactors, autocatalytic reactors, and considerations for optimizing reactor performance and operating conditions. It addresses recycle stream ratios, performance equations, temperature progression, and non-ideal flow concepts such as residence time distribution, states of aggregation, and mixing effects.
This document discusses different types of chemical reactors, including plug flow reactors and continuous stirred tank reactors (CSTR). It provides information on their design considerations, advantages, disadvantages, and equations. Plug flow reactors allow minimal back mixing and each particle has the same residence time. CSTRs ensure proper mixing through the use of an impeller and assume perfect mixing. The document also provides examples of design equations for ideal reactors and discusses factors to consider for reactor selection like yield, cost, and safety.
Dynamic modeling and simulation of catalyticJhonatan Soto
This document summarizes a study on dynamic modeling and simulation of catalytic naphtha reforming. The dynamic model developed includes reaction kinetics, heat exchanger models, and furnace models. Kinetic modeling of the fixed bed reactors connected in series forms the core of the simulation. Reaction rates are represented using Hougen-Watson Langmuir-Hinshelwood expressions. Simulation results using MATLAB show fair agreement with plant data. The model can capture major dynamics in the reforming process system.
1) A compact fast pyrolysis reactor with Auger-type modules was tested for continuous liquid biofuel production from biomass.
2) Analysis of the produced pyrolysis oil showed that it took approximately 10 hours for the oil to fully condense when operating the reactor at a feedstock rate of 25 kg/h. Faster feedstock rates decreased the condensation time.
3) After 10 hours of operation, the pyrolysis oil properties remained stable, indicating steady performance of the reactor. The oil had physical and chemical properties typical of wood pyrolysis oils and a heating value of approximately 20 MJ/kg.
Effect of Operating Conditions on CSTR performance: an Experimental StudyIJERA Editor
In this work, Saponification reaction of ethyl acetate by sodium hydroxide is studied experimentally in a continuous stirred tank reactor at 1 atmospheric pressure. The aim of this study is to investigate the influence of operating conditions on the conversion and specific rate constant. The parameters considered for analysis are temperature, feed flow rate, residence time, volume of reactor and stirrer rate. The steady state conversion of 0.45 achieved after a period of 30 minutes. Conversion decreases with increase of reactant flow rate due to decrease of residence time. The stirrer rate has a positive effect on the conversion and rate constant. Specific rate constant and conversion increase with temperature within the studied temperature range. Within the range of reactor volume selected for analysis, conversion increases with increase in reactor volume. The results obtained in this study may be helpful in maximizing the conversion of ethyl acetate saponification reaction at industrial scale in a CSTR.
This document provides an overview of different types of reactors used in wastewater treatment processes. It defines reactors as vessels that hold wastewater for treatment and describes common reactor shapes. It then classifies and describes several reactor types including continuously stirred tank reactors, plug flow reactors, completely mixed batch reactors, fluidized bed reactors, packed bed reactors, and sequencing batch reactors. For each reactor type, diagrams are provided and equations are derived for hydraulic retention time and effluent concentrations based on reaction kinetics. Examples are also included to illustrate reactor sizing calculations.
Chato lox tank helium removal for propellant scavenging presentation 2009David Chato
System studies have shown a significant advantage to reusing the hydrogen and oxygen left in
these tanks after landing on the Moon in fuel cells to generate power and water for surface
systems. However in the current lander concepts, the helium used to pressurize the oxygen tank
can substantially degrade fuel cell power and water output by covering the reacting surface with
inert gas. This presentation documents an experimental investigation of methods to remove the
helium pressurant while minimizing the amount of the oxygen lost. This investigation
demonstrated that significant quantities of Helium (>90% mole fraction) remain in the tank after
draining. Although a single vent cycle reduced the helium quantity, large amounts of helium
remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to
reduce the helium to small (<0.2%) quantities. Two vent cycles may be sufficient since once the
tank has been brought up to pressure after the second vent cycle the helium concentration has
been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to
diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be
evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent
cycle is not required).
These slides may be used for a part of Advanced level course in Chemical Reaction Engineering. I taught this course to Masters level students covering 1.5 credit hours.
This document provides an overview of a Polymer Reaction Engineering course. The course goals are to introduce students to reaction engineering, polymerization reactions, kinetics, and reactor design. The course objectives are for students to understand reaction kinetics and apply this to the conceptual design of reactors. The schedule outlines 16 weeks of topics like batch and continuous reactor design, polymerization reactions, and a final design project.
This document discusses control of polymerization reactors. It outlines several key control problems including controlling reaction rates and temperature, monomer conversion and production rates, molecular weight and distribution, copolymer composition, and particle size and distribution. It then discusses various measurement techniques used for monitoring these properties, including viscosity, composition, surface tension, molecular weight distribution, and particle size distribution. Control is achieved through manipulation of parameters like temperature, feed rates, catalysts, and chain transfer agents.
1) Fluid catalytic cracking (FCC) is a process that uses a catalyst to crack large hydrocarbon molecules in gas oils and residual stocks into smaller molecules to produce lighter products like gasoline.
2) The FCC process involves circulating hot catalyst between a reactor and regenerator. In the reactor, the catalyst cracks the large molecules into smaller ones like gasoline. Coke deposits on the catalyst and is burned off to reheat the catalyst in the regenerator.
3) FCC units produce additional gasoline from heavier fractions of crude oil to correct the imbalance between market demand for gasoline and excess heavy products from distillation. FCC is a critical process in many refineries.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document describes a computational fluid dynamics (CFD) study of methane decomposition into hydrogen and solid carbon in a packed bed fluid catalytic cracking (FCC) reactor. The study used CFD modeling in COMSOL Multiphysics to simulate the decomposition reaction over time in the packed bed reactor. Results showed that increasing the reaction time from 0 to 1000 seconds increased the production of hydrogen from 0 to 42 mol/dm3 and carbon from 0 to 21 mol/dm3, while decreasing methane concentration from 50 to 29 mol/dm3, indicating that decomposition was occurring. Spatial profiles of velocity, concentration, pressure and permeability within the reactor were also determined and discussed.
Computational Fluid Dynamic Study On The Decomposition Of Methane Gas Into Hy...IOSR Journals
This document describes a computational fluid dynamics (CFD) study of methane decomposition into hydrogen and solid carbon in a packed bed fluid catalytic cracking (FCC) reactor. The study used CFD modeling in COMSOL Multiphysics to simulate the reaction over time and space in the reactor. Results showed that increasing reaction time from 0 to 1000 seconds increased hydrogen production from 0 to 42 mol/dm3 and carbon production from 0 to 21 mol/dm3, while decreasing methane concentration from 50 to 29 mol/dm3, indicating decomposition was occurring. Carbon deposition on the catalyst was faster initially but slowed above 500 seconds. When catalyst deactivation was included, less hydrogen and carbon were produced compared to without deactivation, showing it
1) The document presents a CFD model of a fluid catalytic cracking (FCC) riser reactor using an Eulerian-Eulerian multiphase approach to model the gas-solid flow.
2) A four-lump kinetic scheme is used to model the catalytic cracking reactions, and heat transfer between the gas and catalyst phases is modeled using the Ranz-Marshall correlation.
3) The model predicts an increase in gas velocity and a decrease in catalyst temperature along the riser height due to catalytic cracking reactions converting the heavy gas oil feed into lighter products. Product yields of gasoline, light gases, and coke are estimated.
Study on Coupling Model of Methanol Steam Reforming and Simultaneous Hydrogen...IOSR Journals
1) A simplified mechanistic model was developed for coupling methanol steam reforming and hydrogen combustion in microchannels of a parallel plate reactor. The reforming reaction is endothermic and requires heat, which is provided by the exothermic hydrogen combustion reaction in an adjacent channel.
2) Kinetic expressions were used to model the reforming and combustion reactions. MATLAB simulations were performed to analyze parameters like temperature, velocity and conversion. Operative diagrams showed the temperature and velocities required for complete methanol conversion.
3) Efficiency curves were generated based on hydrogen produced versus consumed. With a molar ratio of 0.9664, the maximum efficiency was 86.8%, indicating over 80% efficiency is achievable via coupling of
Simulation of FCC Riser Reactor Based on Ten Lump ModelIJERA Editor
The ten lump strategy and reaction schemes are based on the concentration of the various stocks i.e., paraffins, naphthenes, aromatic and aromatic substituent groups (paraffinic and napthenic groups attached to aromatic rings). The developed model has been studied using C++ programming language using Runge-Kutta Fehlberg mathematical method. At a space time of 4.5 s, the gasoline yield is predicted to be 72 mass % and 67 mass % for naphthenic and paraffinic feedstock respectively. Type of feed determines the yield of gasoline and coke. A highly naphthenic charge stock has given the greatest yield of gasoline among naphthenic, paraffinic and aromatic charge stock. In addition to this, effect of space time and temperature on the yield of coke and gasoline and conversion of gas oil has been presented. Also, the effect of catalyst to oil ratio is also taken in studies.
SCALE-UP OF MICROCHANNEL REACTORS FOR FISCHER-TROPSCHJohn Glenning
The scale-up of microchannel reactors for Fischer-Tropsch synthesis has been demonstrated through multiple scales with equivalent performance. Small single channel reactors and larger reactors with 276 parallel channels showed consistent CO conversion rates of 70-75% and methane selectivity of 8-9% when tested with the same catalyst under identical conditions. This confirms that microchannel reactor performance is unaffected by increasing channel length or number of channels, enabling scale-up while maintaining nearly isothermal conditions ideal for Fischer-Tropsch synthesis.
This document describes a model developed to predict the optimal reaction temperature of an industrial fluid catalytic cracking (FCC) unit riser. A pseudo-homogeneous two-dimensional model was developed using a five-lump reaction scheme. Mass transfer resistance was incorporated to improve accuracy over previous one-dimensional plug flow models. Finite difference methods were used to discretize the governing equations which were then solved using MATLAB. Simulation results identified three temperature regimes for catalyst coking. An optimum temperature range of 786K-788K and catalyst-to-oil ratio range of 4.60-4.71 were predicted to minimize coke on catalyst without reducing gasoline yield.
This document describes a model developed to predict the optimal reaction temperature of an industrial fluid catalytic cracking (FCC) unit riser. A pseudo-homogeneous two-dimensional model was developed using a five-lump reaction scheme. Mass transfer resistance was incorporated to improve accuracy over previous one-dimensional plug flow models. Finite difference methods were used to discretize the governing equations which were then solved using MATLAB. Simulation results identified three temperature regimes for catalyst coking. An optimum temperature range of 786K-788K and catalyst-to-oil ratio range of 4.60-4.71 were predicted to minimize coke on catalyst without reducing gasoline yield.
The document discusses the history and evolution of fluid catalytic cracking (FCC) units from their inception in 1915 up to modern times. FCC units now process about 5.3 million barrels of feedstock per day in the US alone to produce gasoline and other products. Technological improvements over the decades include developments in catalyst materials, unit designs, operating conditions, and products to optimize the catalytic cracking process.
This document discusses catalytic cracking, which breaks down large hydrocarbon molecules into smaller, more useful molecules. It describes the different types of cracking processes and explains that catalytic cracking is most commonly used. Catalytic cracking uses lower temperatures and pressures than thermal cracking by using a catalyst. It provides details on the catalytic cracking process, including that it occurs in three basic functions: reaction, regeneration, and fractionation. It also describes the specific fluid catalytic cracking and moving bed catalytic cracking processes.
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.
Dynamic Modeling for Gas Phase Propylene Copolymerization in a Fluidized Bed ...IJRES Journal
The document presents a dynamic two-phase model for a fluidized bed reactor used to produce polypropylene. The model divides the reactor into an emulsion phase and bubble phase, with reaction assumed to occur in both phases. Simulation results show the temperature profile is lower than previous single-phase models due to considering both phases. Approximately 13% of the produced polymer comes from the bubble phase, demonstrating the importance of accounting for both phases.
Modeling Of Carbon Deposit From Methane Gas On Zeolite Y Catalyst Activity In...IOSR Journals
This document summarizes a study that models carbon deposit from methane gas on Zeolite Y catalyst activity in a packed bed reactor. The study developed two computational fluid dynamic (CFD) models: 1) The first model considered the influence of carbon deposition on catalyst activity over time. Results showed carbon deposition increased over time while methane decreased and hydrogen increased, indicating methane decomposition. 2) The second model investigated the effect of carbon deposits on fluid flow over both time and space. The study aims to provide insight into how carbon deposition affects catalyst activity and gas flow through the packed bed reactor.
This document presents a computational fluid dynamics (CFD) model to study the effects of carbon deposit from methane gas on Zeolite Y catalyst activity in a packed bed reactor. The model considers two cases - the influence of carbon deposition on catalyst activity, and the effect of carbon deposits on fluid flow over time and space. The CFD model is developed using Comsol Multiphysics software and simulates methane decomposition in the packed bed reactor, accounting for reactions, fluid flow, heat transfer, and carbon deposition over time. Results from the first model show increases in hydrogen production and carbon deposition over time, indicating methane decomposition is occurring as well as catalyst deactivation from carbon.
This document summarizes a CFD study on fluidized bed pyrolyzers. The study used two models: 1) a particle pyrolysis model to simulate wood pyrolysis kinetics and heat transfer, and 2) a reactor model in ANSYS FLUENT to model secondary reactions in a fluidized bed. The models examined the effects of feedstock size, fluidized gas temperature, and vapor residence time on liquid fraction yield. The results showed that fluidized gas temperature has a more critical impact than residence time on secondary reactions. Downward vapor flow along the reactor wall was also observed and should be considered in design. The models provide insights into reducing secondary reactions to maximize liquid yield in fluidized bed pyrolysis.
This document summarizes the use of red mud as a catalyst for hydrocracking vacuum residue in the oil refining process. It first provides background on oil refining, noting that vacuum residue is a heavy fraction that is difficult to refine due to coking. Hydrocracking uses hydrogen to crack the heavy molecules, but is limited by expensive catalysts and coking. The document then discusses how red mud, a waste product from aluminum production, can be used as a hydrocracking catalyst. When used as a catalyst, red mud facilitates the breakdown of asphaltenes in vacuum residue and promotes hydrogen uptake, reducing coking by 92% while slightly increasing fuel yields. This makes red mud a more sustainable and cost-effective
performance analysis of steam power plants using ideal reheat rankin cycleIJAEMSJORNAL
In this paper, a hypothetical examination has been done to assess the execution of the power plants that are chipping away at Reheat-Rankin cycle. The execution of cycle was dissected for various (warm, evaporator, condenser weights) values and also warm temperature qualities to demonstrate its impact on cycle warm proficiency. In this work, the heater weights qualities was accepted limited between (10to 26 MPa), the pressure proportion (warm stage weight to evaporator weight) was expected fluctuated in wide range from (0.1 to 1.0), while the condenser weight was accepted shifted between (5 to 25 kPa). And, a variety in warm temperature esteem was done between scopes of (400-600oC) at low weight turbine. The outcomes demonstrate that the warm productivity is considerably upgraded when the pressure proportion lies between (0.25-0.35) and the ideal proficiency is gotten when the pressure proportion and evaporator weight are equivalent to( 0.33 and 26MPa) separately .
Chemical Looping Combustion of Rice HuskIJERA Editor
A thermodynamic investigation of direct chemical looping combustion (CLC) of rice husk is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200˚C and different amounts of oxygen carriers. Chemical equilibrium model was considered for the CLC fuel reactor. The trends in product compositions of the fuel reactor, were determined. Rice husk gasification using 3 moles H2O and 0 moles CO2 per mole carbon (in rice husk) at 1 bar pressure and 900˚C was found to be the best operating point for hundred percent carbon conversion in the fuel reactor. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels.
Chemical Looping Combustion of Rice HuskIJERA Editor
A thermodynamic investigation of direct chemical looping combustion (CLC) of rice husk is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200˚C and different amounts of oxygen carriers. Chemical equilibrium model was considered for the CLC fuel reactor. The trends in product compositions of the fuel reactor, were determined. Rice husk gasification using 3 moles H2O and 0 moles CO2 per mole carbon (in rice husk) at 1 bar pressure and 900˚C was found to be the best operating point for hundred percent carbon conversion in the fuel reactor. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels.
This document proposes methods for generating electricity from speed breakers. It discusses 5 classifications of speed breaker power generators that use different mechanisms: 1) a chain drive mechanism, 2) a rack and pinion system, 3) direct use of the load through a reciprocating device, 4) a translator and stator topology, and 5) a pressure lever mechanism. The document also outlines the advantages of using speed breakers for power generation such as low cost and maintenance and being a renewable source. Some challenges are also noted such as selecting a suitable generator and dealing with rain damage.
Cassava waste water was used as an admixture to replace distilled water in ratios of 5%, 10%, 15%, and 20% for producing sandcrete blocks. 60 sandcrete blocks of size 450mm x 150mm x 225mm were produced with different admixture ratios and a control with 0% admixture. The blocks were cured for 7, 14, 21, and 28 days and then tested for moisture content, specific gravity, water absorption, and compressive strength. Test results showed that blocks with 20% cassava waste water admixture met the minimum compressive strength requirement of 3.30 N/mm2 set by Nigerian standards, indicating the potential of cassava waste water to improve sandcrete block quality and
The document presents a theorem on random fixed points in metric spaces. It begins with introductions to fixed point theory, random fixed point theory, and relevant definitions. The main result is Theorem 3.1, which proves that if a self-mapping E on a complete metric space X satisfies certain contraction conditions involving parameters between 0 and 1, then E has a unique fixed point. The proof constructs a Cauchy sequence that converges to the unique fixed point. The document contributes to the study of random equations and random fixed point theory, which has applications in nonlinear analysis, probability theory, and other fields.
1. The document discusses applying multi-curve reconstruction technology to seismic inversion to improve accuracy and reliability. It focuses on reconstructing SP and RMN curves from well logs that are affected by various distortions.
2. The process of reconstructing the curves involves removing baseline drift, standardizing values, applying linear filtering, and fitting the curves. This removes interference and retains valid lithological information.
3. Reconstructing high quality curves improves the resolution and credibility of seismic inversion results. The method is shown to effectively predict sand distribution with little error.
This document compares the performance of a Minimum-Mean-Square-Error (MMSE) adaptive receiver and a conventional Rake receiver for receiving Ultra-Wideband (UWB) signals over a multipath fading channel. It first describes the UWB pulse shapes and channel model used, including the 6th derivative of the Gaussian pulse and the IEEE 802.15.3a modified Saleh-Valenzuela channel model. It then discusses the Direct-Sequence and Time-Hopping transmission and multiple access schemes for UWB. The document presents the receiver structures for the MMSE adaptive receiver and Rake receiver and compares their performance using MATLAB simulations.
This document summarizes a study on establishing logging interpretation models for reservoir parameters like porosity, permeability, oil saturation, and gas saturation in the Gaotaizi Reservoir of the L Oilfield. Models were developed using core data from 4 wells and include:
1) A porosity model relating acoustic travel time to porosity with an error of 0.92%
2) A permeability model relating permeability to porosity with an error of 0.31%
3) An oil saturation model using resistivity data with empirically determined parameters
4) A method to determine original gas saturation from mercury injection data.
Application of the models improved interpretation precision and allowed recalculation of oil and gas reserves for the
This document discusses predicting spam videos on social media platforms using machine learning. It proposes using attributes like number of likes, comments, and view count to classify videos as spam or not spam. A predictive algorithm is developed that uses threshold values for attributes and natural language processing of comments to classify videos. Testing of the algorithm on a dataset achieved a spam prediction precision of 93.6%. Issues with small datasets decreasing accuracy are also discussed, along with continuing work to address this issue.
1) The study experimentally evaluated the compatibility relationship between polymer solutions and oil layers through core flooding tests with different permeability cores.
2) The results showed that injection rate decreased with increasing polymer concentration and molecular weight, and increased with permeability.
3) Based on the results, boundaries for injection capability were established and a compatibility chart was proposed to guide polymer solution selection for different sedimentary microfacies in the field based on permeability and pore size.
1. The document discusses the identification of lithologic traps in the D3 Member of the Gaonan Region using seismic attribute analysis, acoustic impedance inversion, and sedimentary microfacies analysis.
2. Several lithologic traps were identified in the I and II oil groups of the D3 Member, with the largest trap located between wells G46 and G146X1 covering an area of about 2.35 km2.
3. Impedance inversion, seismic attribute analysis, and sedimentary microfacies characterization using 3D seismic data helped determine the location and development of effective lithologic traps in the thin sandstone-shale interbeds of the target stratum.
This document examines using coal ash as a partial replacement for cement in concrete. Coal ash was substituted for cement at rates of 5%, 10%, and 15% by weight. Testing found that concrete with a 5% substitution of coal ash exhibited only a slight decrease in compressive strength of 2% at 28 days while gaining improved workability. Higher substitution rates of 10% and 15% coal ash led to greater decreases in compressive and tensile strength. The study concludes that a 5% substitution of coal ash for cement provides benefits of reduced cost and improved workability with minimal strength impacts, representing an effective use of a waste material that addresses sustainability.
Accounting professional judgment involves handling accounting events and compiling financial reports according to regulations and standards. However, professional judgment is sometimes manipulated to distort accounting information. The document discusses three ways manipulation occurs: 1) abandoning accounting principles, 2) optional changes to accounting policies, and 3) abuse of accounting estimates. The causes of manipulation include distorted motivations from corporate governance issues and catering to various stakeholder interests. Strengthening supervision and improving the accounting system are proposed to manage manipulation of professional judgment.
The document discusses research on the distribution of oil and water in the eastern block of the Chao202-2 area in China. It establishes standards for identifying oil, poor oil, dry, and water layers using well logging data. Analysis shows structural reservoirs are dominant and fault and sand body configuration control oil-water distribution. Oil-water distribution varies between fault blocks from "up oil, bottom water" to "up water, bottom oil" depending on structure and sand body development.
The document describes an intelligent fault diagnosis system for reciprocating pumps that uses pressure and flow signals as inputs. It consists of hardware for data acquisition and a software system for signal processing, feature extraction, and fault diagnosis using wavelet neural networks. The system was able to accurately diagnose three main fault types - seal ring faults, valve damage, and spring faults - based on differences observed in the pressure curves. Testing on over 12 samples of each fault type achieved a correct diagnosis rate of over 94%. The system provides a fast and effective means of remotely monitoring reciprocating pumps and identifying faults.
This document discusses the application of meta-learning algorithms in banking sector data mining for fraud detection. It proposes using Classification and Regression Tree (CART), AdaBoost, LogitBoost, Bagging and Dagging algorithms for classification of banking transaction data. The experimental results show that Bagging algorithm has the best performance with the lowest misclassification rate, making it effective for banking fraud detection through data mining. Data mining can help banks detect patterns for applications like credit scoring, payment default prediction, fraud detection and risk management by analyzing customer transaction history and loan details.
This document presents a numerical solution for unsteady heat and mass transfer flow past an infinite vertical plate with variable thermal conductivity, taking into account Dufour number and heat source effects. The governing equations are non-linear and coupled, and were solved numerically using an implicit finite difference scheme. Various parameters, including Dufour number and heat source, were found to influence the velocity, temperature, and concentration profiles. Skin friction, Nusselt number, and Sherwood number were also calculated.
The document discusses methods for obtaining a background image using depth information from a depth camera to more accurately extract foreground objects. It finds that accumulating depth images and taking the median value at each pixel provides the most accurate background image. The accuracy of three methods - average, median, and mode - are evaluated using simulated depth data of a captured plane. The median method provides the best results, followed by average, while mode performs worst. More accumulated images provide a more accurate background image across all methods.
This document presents a mathematical model for determining the minimum overtaking sight distance (OSDm) required for an ascending vehicle to safely pass another slower vehicle on a single lane highway with an incline. It defines sight distance, stopping sight distance, perception-reaction time and derives equations to calculate the reaction distance (d1), overtaking distance (d2), vehicle travel distance during overtaking (d3), and total minimum OSDm based on vehicle characteristics, road geometry, and coefficients of friction. The safe overtaking zone is defined as 3 times the minimum OSDm. The model accounts for effects of slope angle and aims to satisfy laws of mechanics for overtaking maneuvers on inclined two-way single lane highways.
This document discusses a novel technique for better analysis of ice properties using Kalman filtering. It summarizes previous research on sea ice segmentation using SAR imagery and dual polarization techniques. It proposes using an automated SAR algorithm along with Kalman filtering to more accurately detect sea ice properties from RADARSAT1 and RADARSAT2 imagery data. The document reviews techniques for image segmentation, dual polarization, PMA detection, and related work on sea ice classification using statistical ice properties, edge preserving region models, and object extraction methods.
This document summarizes a study on the bioaccumulation of heavy metals in bass fish (Morone Saxatilis) caught at Rodoni Cape in the Adriatic Sea in Albania. Samples of bass fish were collected from five sites and analyzed for mercury, lead, and cadmium levels in their muscles. The concentrations of heavy metals varied between fish and sites but were below international limits for human consumption. While the fish were found to be safe for eating, the study recommends continuous monitoring of metal levels in fish from the area due to various factors that can influence metal uptake over time.
This document discusses optimal maintenance policies for repairable systems with linearly increasing hazard rates. It considers a system with a constant repair rate and predetermined availability requirement. There are two maintenance policies: corrective maintenance only, and preventive maintenance at set time intervals. The goal is to determine the preventive maintenance interval that guarantees the availability requirement at minimum cost. Equations are developed to calculate the availability under each policy and the optimal preventive maintenance interval based on both availability and cost. A numerical example is provided to demonstrate the decision process in determining the optimal policy.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/temporal-event-neural-networks-a-more-efficient-alternative-to-the-transformer-a-presentation-from-brainchip/
Chris Jones, Director of Product Management at BrainChip , presents the “Temporal Event Neural Networks: A More Efficient Alternative to the Transformer” tutorial at the May 2024 Embedded Vision Summit.
The expansion of AI services necessitates enhanced computational capabilities on edge devices. Temporal Event Neural Networks (TENNs), developed by BrainChip, represent a novel and highly efficient state-space network. TENNs demonstrate exceptional proficiency in handling multi-dimensional streaming data, facilitating advancements in object detection, action recognition, speech enhancement and language model/sequence generation. Through the utilization of polynomial-based continuous convolutions, TENNs streamline models, expedite training processes and significantly diminish memory requirements, achieving notable reductions of up to 50x in parameters and 5,000x in energy consumption compared to prevailing methodologies like transformers.
Integration with BrainChip’s Akida neuromorphic hardware IP further enhances TENNs’ capabilities, enabling the realization of highly capable, portable and passively cooled edge devices. This presentation delves into the technical innovations underlying TENNs, presents real-world benchmarks, and elucidates how this cutting-edge approach is positioned to revolutionize edge AI across diverse applications.
Discover top-tier mobile app development services, offering innovative solutions for iOS and Android. Enhance your business with custom, user-friendly mobile applications.
"Scaling RAG Applications to serve millions of users", Kevin GoedeckeFwdays
How we managed to grow and scale a RAG application from zero to thousands of users in 7 months. Lessons from technical challenges around managing high load for LLMs, RAGs and Vector databases.
Northern Engraving | Nameplate Manufacturing Process - 2024Northern Engraving
Manufacturing custom quality metal nameplates and badges involves several standard operations. Processes include sheet prep, lithography, screening, coating, punch press and inspection. All decoration is completed in the flat sheet with adhesive and tooling operations following. The possibilities for creating unique durable nameplates are endless. How will you create your brand identity? We can help!
Essentials of Automations: Exploring Attributes & Automation ParametersSafe Software
Building automations in FME Flow can save time, money, and help businesses scale by eliminating data silos and providing data to stakeholders in real-time. One essential component to orchestrating complex automations is the use of attributes & automation parameters (both formerly known as “keys”). In fact, it’s unlikely you’ll ever build an Automation without using these components, but what exactly are they?
Attributes & automation parameters enable the automation author to pass data values from one automation component to the next. During this webinar, our FME Flow Specialists will cover leveraging the three types of these output attributes & parameters in FME Flow: Event, Custom, and Automation. As a bonus, they’ll also be making use of the Split-Merge Block functionality.
You’ll leave this webinar with a better understanding of how to maximize the potential of automations by making use of attributes & automation parameters, with the ultimate goal of setting your enterprise integration workflows up on autopilot.
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
In our second session, we shall learn all about the main features and fundamentals of UiPath Studio that enable us to use the building blocks for any automation project.
📕 Detailed agenda:
Variables and Datatypes
Workflow Layouts
Arguments
Control Flows and Loops
Conditional Statements
💻 Extra training through UiPath Academy:
Variables, Constants, and Arguments in Studio
Control Flow in Studio
This talk will cover ScyllaDB Architecture from the cluster-level view and zoom in on data distribution and internal node architecture. In the process, we will learn the secret sauce used to get ScyllaDB's high availability and superior performance. We will also touch on the upcoming changes to ScyllaDB architecture, moving to strongly consistent metadata and tablets.
inQuba Webinar Mastering Customer Journey Management with Dr Graham HillLizaNolte
HERE IS YOUR WEBINAR CONTENT! 'Mastering Customer Journey Management with Dr. Graham Hill'. We hope you find the webinar recording both insightful and enjoyable.
In this webinar, we explored essential aspects of Customer Journey Management and personalization. Here’s a summary of the key insights and topics discussed:
Key Takeaways:
Understanding the Customer Journey: Dr. Hill emphasized the importance of mapping and understanding the complete customer journey to identify touchpoints and opportunities for improvement.
Personalization Strategies: We discussed how to leverage data and insights to create personalized experiences that resonate with customers.
Technology Integration: Insights were shared on how inQuba’s advanced technology can streamline customer interactions and drive operational efficiency.
The Department of Veteran Affairs (VA) invited Taylor Paschal, Knowledge & Information Management Consultant at Enterprise Knowledge, to speak at a Knowledge Management Lunch and Learn hosted on June 12, 2024. All Office of Administration staff were invited to attend and received professional development credit for participating in the voluntary event.
The objectives of the Lunch and Learn presentation were to:
- Review what KM ‘is’ and ‘isn’t’
- Understand the value of KM and the benefits of engaging
- Define and reflect on your “what’s in it for me?”
- Share actionable ways you can participate in Knowledge - - Capture & Transfer
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
"Choosing proper type of scaling", Olena SyrotaFwdays
Imagine an IoT processing system that is already quite mature and production-ready and for which client coverage is growing and scaling and performance aspects are life and death questions. The system has Redis, MongoDB, and stream processing based on ksqldb. In this talk, firstly, we will analyze scaling approaches and then select the proper ones for our system.
From Natural Language to Structured Solr Queries using LLMsSease
This talk draws on experimentation to enable AI applications with Solr. One important use case is to use AI for better accessibility and discoverability of the data: while User eXperience techniques, lexical search improvements, and data harmonization can take organizations to a good level of accessibility, a structural (or “cognitive” gap) remains between the data user needs and the data producer constraints.
That is where AI – and most importantly, Natural Language Processing and Large Language Model techniques – could make a difference. This natural language, conversational engine could facilitate access and usage of the data leveraging the semantics of any data source.
The objective of the presentation is to propose a technical approach and a way forward to achieve this goal.
The key concept is to enable users to express their search queries in natural language, which the LLM then enriches, interprets, and translates into structured queries based on the Solr index’s metadata.
This approach leverages the LLM’s ability to understand the nuances of natural language and the structure of documents within Apache Solr.
The LLM acts as an intermediary agent, offering a transparent experience to users automatically and potentially uncovering relevant documents that conventional search methods might overlook. The presentation will include the results of this experimental work, lessons learned, best practices, and the scope of future work that should improve the approach and make it production-ready.
Introduction of Cybersecurity with OSS at Code Europe 2024Hiroshi SHIBATA
I develop the Ruby programming language, RubyGems, and Bundler, which are package managers for Ruby. Today, I will introduce how to enhance the security of your application using open-source software (OSS) examples from Ruby and RubyGems.
The first topic is CVE (Common Vulnerabilities and Exposures). I have published CVEs many times. But what exactly is a CVE? I'll provide a basic understanding of CVEs and explain how to detect and handle vulnerabilities in OSS.
Next, let's discuss package managers. Package managers play a critical role in the OSS ecosystem. I'll explain how to manage library dependencies in your application.
I'll share insights into how the Ruby and RubyGems core team works to keep our ecosystem safe. By the end of this talk, you'll have a better understanding of how to safeguard your code.
Must Know Postgres Extension for DBA and Developer during MigrationMydbops
Mydbops Opensource Database Meetup 16
Topic: Must-Know PostgreSQL Extensions for Developers and DBAs During Migration
Speaker: Deepak Mahto, Founder of DataCloudGaze Consulting
Date & Time: 8th June | 10 AM - 1 PM IST
Venue: Bangalore International Centre, Bangalore
Abstract: Discover how PostgreSQL extensions can be your secret weapon! This talk explores how key extensions enhance database capabilities and streamline the migration process for users moving from other relational databases like Oracle.
Key Takeaways:
* Learn about crucial extensions like oracle_fdw, pgtt, and pg_audit that ease migration complexities.
* Gain valuable strategies for implementing these extensions in PostgreSQL to achieve license freedom.
* Discover how these key extensions can empower both developers and DBAs during the migration process.
* Don't miss this chance to gain practical knowledge from an industry expert and stay updated on the latest open-source database trends.
Mydbops Managed Services specializes in taking the pain out of database management while optimizing performance. Since 2015, we have been providing top-notch support and assistance for the top three open-source databases: MySQL, MongoDB, and PostgreSQL.
Our team offers a wide range of services, including assistance, support, consulting, 24/7 operations, and expertise in all relevant technologies. We help organizations improve their database's performance, scalability, efficiency, and availability.
Contact us: info@mydbops.com
Visit: https://www.mydbops.com/
Follow us on LinkedIn: https://in.linkedin.com/company/mydbops
For more details and updates, please follow up the below links.
Meetup Page : https://www.meetup.com/mydbops-databa...
Twitter: https://twitter.com/mydbopsofficial
Blogs: https://www.mydbops.com/blog/
Facebook(Meta): https://www.facebook.com/mydbops/
Principle of conventional tomography-Bibash Shahi ppt..pptx
D041222231
1. IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org
ISSN (e): 2250-3021, ISSN (p): 2278-8719
Vol. 04, Issue 12 (December 2014), ||V2|| PP 22-31
International organization of Scientific Research 22 | P a g e
Development of Models for Fluid Catalytic Cracking Fluidized
Bed Reactor Using Four-Lump Kinetic Scheme
Dagde, Kenneth Kekpugile2
and Akpa, Jackson Gunorubon2
Department of Chemical/Petrochemical Engineering
Rivers State University of Science and Technology,
Port-Harcourt, Rivers State, Nigeria
Abstract: Models’ describing the steady state behavior of the fluidized bed reactor for catalytic cracking of gas
oil has been presented. The four-lump kinetic scheme was used to describe the cracking reactions occurring in
the reactor while the two-phase hypothesis comprising of the bubble and the emulsion phases of Kunii and
Levenspiel was used to describe the fluidized bed models. The model equations consisted of sets of non linear
first order differential equations and sets of quadratic equations. The differential equations were integrated
numerically using the fourth order Runge-Kutta algorithm while the quadratic equations were solved using
formulae method. Results predicted by the model were validated using data obtained from a operating plant,
deviations of -21.99%, 9.85%, 5.27%, and 4.12% were obtained for the conversion of gas oil, yields of
gasoline, gases and coke respectively. The results shows that plug flow- plug flow combination of the fluidized
bed gave a higher conversion of gasoil than the plug flow-CSTR model. Sensitivity analyses showed that
superficial velocity, bubble diameter, catalyst bed height, reactor temperature, catalyst-to-gasoil ratio and the
diameter of reactor are important process variables that affect the yield of the products.
Keywords: Gasoil cracking, Four-lump kinetics, Reactor model
I. Introduction
Fluidization is the operation by which solid particles are transformed into a fluid like state through
suspension in a gas or liquid. Cracking is the breaking down of higher hydrocarbon molecules into products of
lower molecular weight. This process can either be thermal or catalytic. Catalytic cracking involves the
breaking down of higher molecular hydrocarbon in the presence of a catalyst and high temperature. It can be
carried out in a continuous, slowly descending layer of spherical catalysts or in a fluidized bed of a powdered or
micro-spherical catalyst [1]. Fluid catalytic cracking (FCC) is one of the most important processes in any
modern refinery; employed for the conversion of straight-run atmospheric gas-oil, vacuum residues, and other
related heavy stocks, into a broad spectrum of products in the presence of a catalyst. The products obtained
from an FCC unit include fuel gas, liquid petroleum gas, high-octane gasoline, light fuel oil, diesel oil, heavy
fuel oil, etc. Fluid catalytic cracking unit consists of a reaction section and a fractionating section that operate
together as an integrated processing unit. The reaction section has two reactors: (1) the riser-reactor where
almost all the endothermic cracking reactions and coke deposition on the catalysts occur, and (2) The
regenerator – reactor, where air is used to burn-off the accumulated coke on the catalyst. The catalyst
regenerated process also provides the heat required for the endothermic cracking reactions in the riser- reactor.
In the FCC unit, the catalyst and the feed enter the riser-reactor as a dense bed. The catalyst is pneumatically
carried upwards by the dispersing steam and thereby vaporizing the gas-oil feed. It is during this period of
conveying the catalysts that catalytic cracking of gas oil (feed) takes place through efficient and effective
catalyst and gas oil intimate contact. The catalysts later becomes deactivated due to coke deposition on it and the
spent-catalyst slide valve in the riser-reactor and enters the top of the regenerator. The major function of the
regenerator is to oxidize the coke on the spent catalyst with oxygen to form carbon monoxide, carbon dioxide
and water, thereby ultimately reactivating the catalysts. Within the entire refinery process, FCC process offers
the greatest potential for increasing productivity, even a small improvement giving higher gasoline yields can
result in a substantial economic gain due to the risen need of this desired products, gasoline. Thus, the economic
incentive for a better understanding and modeling of the FCC process is immense [2].
The Fluid Catalytic Cracking Riser Reactor has been modeled as a single transport (plug-flow) reactor
by several authors [1],[3],[4],[5],[6]. The FCC Riser reactor has also been modeled as two-phase fluidized bed
reactor with the assumption that the catalyst in the emulsion phase are in equilibrium with the gases in the
bubble phase, and the gases in the both phases are in tubular flow[7],[8],[9]. These authors modeled the both
phases as tubular (plug-flow) reactors connected in parallel.
In the present study, the catalytic cracking fluidized bed is modeled as two-phase (bubble and
emulsion); however, the gases in the emulsion phase is assumed to be at minimum fluidization velocity and
totally mixed [10], while the gases in the bubble phase are above the minimum fluidization velocity and in plug-
2. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 23 | P a g e
flow mode, noting that the sum of the respective velocities in both phases equals to constant superficial velocity.
The assumption of the minimum fluidization velocity in the emulsion is justified by the fact that the catalysts
spend longer time (low velocity) in the emulsion phase with inherent high catalyst density than in the bubble
phase. The models presented adopted the four-lump kinetic scheme proposed by Lee et al. [11] due to its
advantage of predicting the amount of coke deposited on the catalyst used for heat integration in the system to
simulate the riser reactor of a functional FCC unit in Nigerian Refinery.
II. Model Equations
2.1 Kinetic Model
The Figure 1 represents the reaction scheme for the four lump kinetic models for catalytic cracking of gas oil.
Figure 1: The four lump kinetic model
The rate of the reactions denoted by (– rij) is the mass of reactant converted per unit mass of reactant per volume
of bubbles per unit time. It is expressed mathematically as:
(–rij) = kij yi ij (1)
Where: rij is the rate of reaction of reactant (i) and product (j), kij is the rate constant, yi =
mass fraction of species i, = deactivation constant, I = reactant, j = product.
The rate equation for gas oil, gasoline LPG and coke are written in terms of their mass fractions as follows:
(– r1) = (k12 + k13 + k14) 2
1y (2)
(– r2) =
22423
2
112 )( ykkyk (3)
(– r3) = -
223
2
113 ykyk (4)
(– r4) = -
224
2
114 ykyk (5)
where, k12, k13 and k14 are the kinetic rate constant for the production of gasoline, gases and coke from gas oil.
k23 and k24 are the kinetic rate constant for the production of gases and coke for gasoline respectively. is the
deactivation constant, y1, y2, y3 and y4 are the mass fraction of gas oil, gasoline, gases and coke respectively.
2.3 The Reactor Model
Figure 2 shows a hypothetical representation of a two-phase fluidized bed reactor. The fluidized bed is
modeled as a two-phased model with the bubble phase being modeled as a plug flow reactor and the emulsion
phase as continuous stirred tank reactor (CSTR). The basis of modeling the emulsion phase as a CSTR dwells
on the fact that there is violent motion of solids which leads to mixing in the gas phase [12].
Gas oil (1) Gasoline (2)
Gases (C1 – C4)
(3)
Coke (4)
K12
K13
K14
K24
K23
3. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 24 | P a g e
Figure 2: Two phase fluidize Bed
where, Uo is the superficial velocity, iG is the density of gas oil, Ue is the velocity of the emulsion phase, Umf
is the minimum superficial velocity, Ub is the velocity of the bubble phase, ib and ie are the densities of the
babble and emulsion phases respectively, is the total outlet density.
In the derivation of the mathematical models for catalytic cracking of gas oil to products, the following
assumptions were made:
1. Feed entering the bed is at incipient velocity Uo, and is partitioned between the emulsion phase where the
velocity is that of minimum fluidzation, Umf, and the bubble phase, where the velocity is Uo – Umf.
2. Isothermal condition throughout the reactor due to the vigorous agitation of the bed.
3. The bubble phase has high gas velocity and contains no solid particle hence no reaction takes place
therefore it is modeled as plug flower reactor.
4. The emulsion phase is modeled as a CSTR since there is total mixing due to the definite flow pattern of
solids.
5. Reaction occurs in the emulsion phase since it contains solid catalyst particles.
6. Interchange of mass occurs between bubble and emulsion phases.
7. Solid particle are perfectly mixed and of uniform sizes.
8. Steady state conditions are assumed.
2.4 The Continuity Equation
2.4.1 The Bubble phase
The law of conservation of mass for a reacting component is applied on a differential element of the
bubble phase of the fluidized to give:
dl
dyU ibb
= (– ri) + kbe (yib – yie) (6)
Equation (6) represents the model equation for the bubble phase.
2.4.2 The Emulsion Phase
The law of conservation of mass for a reacting component is applied in the entire system of the emulsion phase
of the fluidized bed to give:
yie =
)(
)(
LKU
LykLryU
bee
ibbeiieoe
(7)
Equation (7) is the model equation for the emulsion phase.
Recalling the model equation of bubble phase, equation (6) and that of emulsion phase, equation (7) and
representing them in dimensionless form by defining a dimensionless bed Z, we have:
Z = FL
L
; L = LFZ (8)
where Z is the dimensionless bed height, LF is the catalyst bed height. Differentiating equation (8) gives:
dL = LF dZ (9)
Substituting equation (8) and (9) into equation (6) and (7) gives:
dZ
ib
i
ie
Ub = Uo - Umf
Uo, io
Ue = Umf
ib + dib Kbe
ib
4. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 25 | P a g e
dZ
dyib
= b
F
U
L
ri
)(
–
)( ieib
b
Fbe
yy
U
Lk
(10)
yie =
ZLkU
zLykZLriyU
Fbee
FiebeFieob
)(
(11)
Substituting the kinetic rate equation (2, 3, 4, 5) into both model equations (10) and (11), for the respective
reactant and products, give:
dZ
dy b1
=
2
141312 ibykkk
)( ieib
b
Fbe
b
F
yy
U
LK
U
L
(12)
y1e =
ZLkU
ZLyKZLykkk
Fbee
FibbeFib
2
141312
(13)
dZ
dy b2
=
bib ykkyk 22423
2
12 )(
)( ieib
b
Fbe
b
F
yy
U
LK
U
L
(14)
y2e =
ZLkU
ZLyKZLykkykyU
Fbee
FbbeFeibeoe
222423
2
122 )(
(15)
dZ
dy b3
=
bib ykyk 223
3
13
)( 33 eb
b
Fbe
b
F
yy
U
Lk
U
L
(16)
y3e =
ZLkU
ZLykZLykykyU
Fbee
FbbeFeibeoe
3233
3
133
(17)
dZ
dy b4
=
bib ykyk 424
4
14
)( 44 eb
b
Fbe
b
F
yy
U
Lk
U
L
(18)
y4e =
ZLkU
ZLykZLykykyU
Fbee
FbbeFeibeoe
4224
4
144
(19)
2.5 Model Equations Parameters Evaluation
2.5.1 Mean Activity of the Catalyst,
The mean activity for mixed flow of catalyst in a fluidized bed reactor is given by Kunni and Levenspiel [1] as:
= meandk 1
1
(20)
But the dependence of the rate constant, kd on reaction temperature follows the Arrhenius law.
kd = kdo exp
RT
E
(21)
The mean residence time, mean of the catalyst in the reactor is given by:
mean = catalysto
reactorV
=
catalystofrateflowVolumetric
reactorofVolume
(22)
But, Vreactor = ARLFZ (23)
o catalyst = s
GR CTOF
(24)
where, s is the density of catalyst, FGR is the mass flow rate of gas oil, CTO is the catalyst to gas oil
ratio.
The mean residence time becomes:
mean =
CTOF
ZLAs
GR
FR
(25)
5. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 26 | P a g e
Hence, substituting equations (21) and (25) into (20) yields:
=
ZLAs
RT
E
kFCTO
FCTO
FRdoGR
GR
exp
(26)
2.5.2 Specification of Fluidized Bed Parameters
Using the Davidson’s theoretical expression for bubble-cloud circulation and the Higbie theory for the
cloud-emulsion diffusion, the interchange coefficient between bubble-cloud and cloud-emulsion phases is given
by Kunii and Levenspiel [1]:
Kbc = 4.5
85.5
b
mf
d
U
4
5
4
1
2
1
db
gD
(27)
Kce = 6.78
2
1
3
b
bemf
d
DU
(28)
The interchange between bubble- emulsion phases is given by rule of addition of two parallel resistances:
beK
1
= bcK
1
+ ccK
1
(29)
Bubble velocity Ub is related to the superficial gas velocity Uo, the velocity at incipient fluidization, Umf and
bubble db, by the Davidson model as:
Ub = Uo – Umf + 0.711 (gdb) ½ (30)
The rise velocity of the emulsion gas is given by:
Ue = mf
mfU
(31)
2.5.3 Exit Mass Fraction
The exit mass fractions of the respective components are given by Dagde and Puyate [9]:
y1 = y1b + (1- ) y1e (32)
y2 = y2b + (1- ) y2e (33)
y3 = y3b + (1- ) y3e (34)
y4 = y4b + (1- ) y4e (35)
where = 1 – o
mf
U
U
(36)
2.6 Materials And Method
2.6.1 Operating Parameters
The parameters were expected from the plant data from the FCC unit of the New Port Harcourt
Refinery, Nigeria. Table 1 shows the physical properties of the feed and products while Table 2 shows the
properties of the catalyst and also heats of reaction. The feedstock composition is shown in Table 3; the air and
hydrocarbon physical properties were obtained from the API Data Book [13]. Table 4 shows the reactor
dimensions.
Table 1: Properties of feed and products of FCC plant [14]
Components API Gravity Composition weight % Flow rate
Gas oil feed 21.2 100 67.8
Fuel gas – 5.4 3.66
C3 LPG – 6.3 4.27
C4 LPG – 10.7 4.27
Gasoline 60.0 45.9 31.12
Light Cycle oil 14.0 17.8 12.07
Bottoms 0.5 8.8 5.97
Coke – 5.1 3.46
6. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 27 | P a g e
Table 2: Physical properties and heat of reactions of reacting species [3]
Parameters Values
Hydrocarbons
Vapour density, kgm–3 9.52
Liquid density at 288K, kgm–3 924.8
Specific heat of gas, Kj.kg–1 k–1 3.3
Specific heat liquid, Kj.kg–1 k–1 2.67
Heat of vapourization, Kj.kg–1 k–1 156
Vapourization temperature, K. 698
Catalyst
Catalyst Bulk density, kgm–3 975
Particle size, m 75 x 10–6
Mass flowrate of catalysts from 1729750
Reactor to regenerator, kg/s
Table 3: Feedstock composition (Mass spectroscopic method) % mass [14]
Hydrocarbon % Mass
Paraffins 35.4
Naphthenes 16.1
Aromatics 48.5
Table 4: FCC Unit dimensions [14]
Parameters Value (cm)
Reactor length 22.9
Reactor diameter 2.9
Cyclone height 14.24
Cyclone diameter 1.5
Disengage height 24.49
The preheated values of the activation energy and the pre-exponential factor, E and ko of the four-lump kinetic
scheme are shown in Table 5:
Table 5: Predicted values of activation energy and frequency of pre-exponential factor [11]
Reaction Path Activation Energy Pre-exponential factor
Gas oil to gasoline 66994 221.611
Gasoline to gases 83283 1263.611
Gas oil to coke 62121 10.4583
Gasoline to gases 54191 0.90417
Gasoline to coke 140008 2210.2778
3.6.2 Solution Technique
The model equations developed gave a set of four ordinary differential equations for the bubble phase
and a set of four quadratic equations for the emulsion phase The ordinary differential equations for the bubble
phase were solved numerically by using fourth order Runge-Kutta method while the emulsion phase quadratic
equations were evaluated using the quadratic formula adapted to the visual basic program. Since the gas oil is
cracked into the various products, the mass fraction of gas oil at the inlet (L = 0) of the reactor is unity while the
mass fraction of the products at the inlet are equal to zero. These initial boundary conditions are stated
mathematically as:
Z = 0: y1b0 = y1e0 = 1 and y2b0 = y2e0 = y3b0 = y3e0 = y4b0 = y4e0 = 0
where y1b0 and y1e0 are the inlet mass fractions of gas oil in the bubble end emulsion phases respectively; yib0
= yie0 are the inlet mass fractions of the products in the bubble and emulsion phases respectively, with i= 2,3,4
as gasoline, gases and coke respectively.
III. Results And Discussion
Table 6 shows the comparison between plant yields and predictions from the model (Equations 12 –
19) for the (CSTR/Plug flow), indicating that the predicted data agree reasonably well with plant data and the
plug flow-plug flow model [8]. The prediction of coke yield which is the major advantage of the four-lump
kinetic scheme adopted in this model matches the plant data very closely. These results show deviations ranging
from 4.118% to 21.992% for CSTR/plug flow model and 3.8% to 10% for plug flow/plug flow model adopted
from Oboho et al. [8].
7. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 28 | P a g e
Table 6: Comparison of Model Predictions with Industrial FCC riser reactor yields
Model Prediction % Deviation.
Parameters Plug/ CSTR Plug/ Plug Plant Data Plug/ CSTR Plug/ Plug
Gasoline 0.4138 0.4131 0.4590 9.847 10.00
H/C Gases 0.2122 0.2620 0.2240 5.268 -3.800
Coke 0.0489 0.0483 0.0510 4.118 5.294
Gas Oil 0.3245 0.2863 0.2660 -21.99 -7.090
The fluidized bed (CSTR/plug flow) model predicted lower conversion of gas oil, high yield of gasoline and
coke and low yield of gases as compared to the plug flow/plug flow model. The lower conversion of gas oil is in
agreement with the inherent behaviour of fluidized bed reactors as compared to plug flow riser reactors.
Cheremisinoff and Cheremisnoff [15] substantiated this deviation as inherent in fluidized bed system where
back mixing exist in the emulsion phase, the flow is somewhere between plug and total mixed flow. Also some
portion of the gas oil (feed) may escape without contact with the catalyst due to channeling and by- passing
effects. Hence, the amount of gas oil (feed) available for reaction with the catalysts in the emulsion phase is
reduced, thus conversion of gas oil is apparently low. While the yield of gasoline and coke are high that of gases
is low as compared to the plug flow/ plug flow fluidized bed model.
Figure 3 shows the variation of mass fraction of gas oil, gasoline, gases and coke along dimensionless
bed height. It depicts a gas oil conversion of 67.55%, gasoline yield of 41.38%, hydrocarbon gases yield of
21.22% and coke yield of 4.89%.
Figure 3: Variation of mass fraction of gas oil, gasoline, gases and coke along dimensionless bed height.
It is observed that the mass fraction of gas oil decreases along the bed height, while that of the cracked
products increased along the bed height. Maximum gasoline yield of 42.85% was detected at a bed height of
7.89 meters, on getting to a bed height of 15 meters due to secondary cracking of gasoline. The yields of
hydrocarbon gases and coke continuously increased along bed height.
3.1 Reactor Simulation
Plant performance can be optimized by choosing the optimal set of operating conditions obtained from
a simulation model. Hence a sensitivity analysis is performed to determine the effects of certain process
variables on the performance of the models developed.
3.1.1 Reaction Temperature
From Figure 4, increase in reactor temperature led to an increase in conversion (decrease in mass
fraction of gas oil).
8. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 29 | P a g e
Figure 4: Variation of mass fraction of cracked components with reactor temperature.
At a reactor temperature of 860 K, the conversion increased to 70.61%, and then dropped to 69.97% at a reactor
temperature of 960 K. The yield of gasoline increased with increase in reactor temperature to a maximum of
42.01% at 660 K. Further increase in reactor temperature resulted in a decrease in yield of gasoline which is due
to secondary cracking of gasoline resulting to increased yield of light gases and coke.
3.1.2 Catalyst to Oil Ratio
Figure 5 shows the variation of mass fraction of reactant and products with catalyst to oil ratio. Increase
in catalyst to oil ratio signifies an increase in the catalyst inlet flow rate. This provides more catalyst for the
cracking reaction, increasing the availability of many active sites for the reaction.
Figure 5: Variation of mass fraction of reactant and products with catalyst to oil ratio.
3.1.3 Superficial Velocity
Figure 4.4 shows the effect of the superficial velocity of gas oil on the conversion of gas oil, yield of
gasoline, hydrocarbon gases and coke. Below a superficial velocity of 0.09 m/s, the program did not run
successfully. Thus 0.09 m/s became the minimum superficial velocity value and turned out to give an optimum
yield. It is seen that optimum product yield was attainable at a superficial velocity value of 0.09 m/s, with a gas
oil conversion of 78.81%, yield of 40.28%, and 32.79% and 5.74% for gasoline, hydrocarbon gases and coke
respectively. Above 0.09 m/s, the conversion of gas oil decreased and also the yield of the products reduced.
9. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 30 | P a g e
Figure 6: Variation of mass fraction of reactant and products with superficial velocity.
This was attributed to the fact that at higher superficial velocities, the residence time of the catalyst was low,
resulting to low conversion of gasoil which was caused by channeling and by-passing effect inherent in
fluidized beds at high superficial velocity [10].
3.1.4 Bubble Diameter
The plot on Figure 7 shows that an increase in bubble diameter increases the conversion of gas oil. The
yield of gasoline increased to a maximum of 41.99% at a bubble diameter of 0.08 m. A decrease in gasoline
yield was observed which is due to the slugging effect and the fact that an increase in bubble size causes the
bubble to move upward in a piston-like manner, then disintegrates and rains down thereby creating a local space
velocity different from the overall space velocity [15].
Figure 7: Variation of components mass fraction with bubble diameter.
IV. Conclusion
The fluidized bed model for the catalytic cracking of gas oil using the four-lump kinetic scheme has
been successfully developed. The results predicted by the model were validated using data obtained from a
operating plant, deviations of -21.99%, 9.85%, 5.27%, and 4.12% were obtained for the conversion of gas oil,
yields of gasoline, gases and coke respectively. The high deviation in gasoil conversion can be attributed to by-
passing in the bubble phase and channeling in the emulsion phase of the fluidized bed.
However, this work, in which the emulsion phase of the fluidized bed was modeled as a continuous
stirred tank reactor, was performed to provide a means of comparison with that in which the emulsion phase was
modeled as a plug flow reactor.
The results shows that plug flow- plug flow combination of the fluidized bed gave a higher conversion
of gasoil, 73.99% [9] than that of this model; the plug flow-CSTR model, 65.55%. This agrees with the
postulate that a plug flow reactor gives a higher conversion than a CSTR. However, the yield of gasoline was
higher in the plug flow-CSTR combination.
10. Development of Models for Fluid Catalytic Cracking Fluidized Bed Reactor Using Four-Lump
International organization of Scientific Research 31 | P a g e
References
[1] D. Kunii and O. Levenspiel,Fluidization Engineering, 2nd Edition, Butterworth, Heinemann, Boston London, 1991, 459 – 474.
[2] J. S. Ahari, A. Farshi, and K. Forsat) A Mathematical Modelling of the Riser Reactor in Industrial FCC unit, Petroleum and Coal,
50 (2) , 2008, 15-21.
[3] H. Ali, S. Rohani and J. P. Corriou, Modeling and Control of a Riser type fluid catalytic cracking (FCC) Unit, Transactions of the
Institution of Chemical Engineers. 75: 1997, 401 – 417.
[4] In-Su Han, and C. B. Chung, Dynamic Modelling and Simulation of a Fluidized Catalytic Cracking Process Part 11: Chemical
Engineering Science, 56: 2001, 1973-1990.
[5] E. O. Oboho, and J. G. Akpa, Modelling of a Fluid Catalytic Cracking (FCC) Riser Reactor – The Four-lump Model, Journal of
Modelling, Design and Management of Engineering Systems, 1: 2002, 39 – 52.
[6] D. M. Nace, S. E Volt and V. M. Weekman, Application of a kinetic model for catalytic cracking effects of change stocks,
Industrial Engineering Chemistry Process Design Development, 10: 1971, 530 – 538.
[7] E. O. Oboho, J. G. Akpa, and K. K. Dagde, Application of the three-lump kinetic model for the catalytic cracking of gas oil in a
fluidized bed reactor, International Journal of Science and Technology 4 (1 & 2): 2005, 29 – 35.
[8] E. O. Oboho, J. G. Akpa, K. K. Dagde and D. O. Njobuenwu, Application of the Four-Lump Kinetic Model for the Simulation of a
Fluidized Bed Reactor for Catalytic Cracking of Gas Oil, Journal of Engineering,16(1): 2006, 27- 44.
[9] K. K. Dagde, and Y. T. Puyate, Modelling and Simulation of Industrial FCC Unit: Analysis Based on Five-Lump Kinetic Scheme
for Gas Oil Cracking, International Journal of Engineering Research and Applications, 2(5): 2012, 698-714.
[10] J. J. Carberry, Chemical and Catalytic Reaction Engineering, McGraw-Hill Book Company, New York, 1996, 556-568.
[11] L. S. Lee, Y. W. Chen, and T. N. Huang, Four-lump Kinetic model for fluid catalytic process, Canadian Journal of chemical
Engineering, 67: 1989, 615 – 619.
[12] G. F. Froment and K. B. Bischoff, Chemical Reactor Analysis and Design, 2nd Edition, John Wiley and Sons, New York, 1990, 566
– 602.
[13] API, Technical Book on Petroleum Refining, American Petroleum Institute, 1967.
[14] NPHRC, New Port Harcourt Refinery Training Project for Staff, Area 3, Process Description, 1, Comerin, 1987.
[15] N. P. Cheremisinoff and P. N. Cheremisinoff, Hydrodynamics of Gas-Solid Fluidization, Gulf Publishing Company, Houston,
1984.