1. High efficiency trays (HET) are designed to improve redistribution of unreacted carbon dioxide and reduce back mixing in urea reactors. They increase urea output and reduce steam consumption.
2. Siphon jet pump trays, a new generation of HET, improve mixing rates in reactor compartments through draft tubes that create a two-phase flow with lower density than the liquid outside, enhancing liquid circulation and mixing. This avoids issues with previous tray designs.
3. Installation of HET and siphon jet pump trays in several plants increased urea production capacity and reduced steam consumption compared to conventional reactor tray designs.
Energy saving in urea plant by modification in heat exchanger and processPrem Baboo
Energy is the prime mover of economic growth and is vital to the sustenance of a modern economy. Improvement in energy
efficiency reduces cost of production & results in environmental benefits, e.g. mitigation of global warming by way of less emission of
Green house gases in the atmosphere. Over the years several energy conservation measures have been taken towards reduction in
specific energy consumption and improvement in energy efficiency. The efforts’ resulted in reduction in specific energy consumption
from 6.27G. Cal/tone of Urea to 5.421 G.Cal/tone of Urea in 2015-16 as shown in the Graph No 1 & 2 with energy & down time.
Further a major modification of all plants is under way. Most of the schemes have been implemented in 2012 and the further
modifications expected to result again reduction of energy consumption for ammonia and Urea plants. This paper described some of
the modification in urea plants implemented recently in May/June 2016.
Calculation of an Ammonia Plant Energy Consumption: Gerard B. Hawkins
Calculation of an Ammonia Plant Energy Consumption:
Case Study: #06023300
Plant Note Book Series: PNBS-0602
CONTENTS
0 SCOPE
1 CALCULATION OF NATURAL GAS PROCESS FEED CONSUMPTION
2 CALCULATION OF NATURAL GAS PROCESS FUEL CONSUMPTION
3 CALCULATION OF NATURAL GAS CONSUMPTION FOR PILOT BURNERS OF FLARES
4 CALCULATION OF DEMIN. WATER FROM DEMIN. UNIT
5 CALCULATION OF DEMIN. WATER TO PACKAGE BOILERS
6 CALCULATION OF MP STEAM EXPORT
7 CALCULATION OF LP STEAM IMPORT
8 DETERMINATION OF ELECTRIC POWER CONSUMPTION
9 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT ISBL
10 ADJUSTMENT OF ELECTRIC POWER CONSUMPTION FOR TEST RUN CONDITIONS
11 CALCULATION OF AMMONIA SHARE IN MP STEAM CONSUMPTION IN UTILITIES
12 CALCULATION OF AMMONIA SHARE IN ELECTRIC POWER CONSUMPTION IN UTILITIES
13 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT OSBL
14 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT
Hydrogen recovery from purge gas(energy saving)Prem Baboo
Ammonia is continuously condensed out of the loop and fresh synthesis gas is added. Because the synthesis gas contains small quantities of methane and argon, these impurities build up in the loop and must be continuously purged to prevent them from exceeding a certain concentration. Although this purge stream can be used to supplement reformer fuel gas, it contains valuable hydrogen which is lost from the ammonia synthesis loop In order to achieve optimum conversion in synthesis convertor, it is necessary to purge a certain quantity of gas from synthesis loop so as to as to reduce inerts concentration in the loop. Purge gas stream from ammonia process contains ammonia, hydrogen, nitrogen and other inert gases. Among them, ammonia itself is the valuable product lost with the purge stream. Moreover it has a serious adverse effect on the environment.This purge gas containing about 60% Hydrogen was fully utilised as primary reformer fuel.
Furnaces in Refinery and Petrochemicals
Process furnaces
Crude distillation unit
Reaction Heaters
Reformer Heater
Heater Performance objectives
Reasons to save Energy
Heater Types
Radiant section
Convection section
Crossover section
Burners
In the plant, ammonia is produced from synthesis gas containing hydrogen and nitrogen in the ratio of approximately 3:1. Besides these components, the synthesis gas contains inert gases such as argon and methane to a limited extent. The source of H2 is demineralized water and the hydrocarbons in the natural gas. The source of N2 is the atmospheric air. The source of CO2 is the hydrocarbons in the natural gas feed. Product ammonia and CO2 is sent to urea plant. The present article intended the description of ammonia plant for natural gas based plants and the possible material balance of some section.
Fired Equipment presentation on Types, Classification and governing Equations...Hassan ElBanhawi
Based on my 8 years of experience in Oil & Gas industry I can claim that you can find here All what you need to know about Fired Equipment. This is an introduction to understand more about their:-
-Types
-Basic Principles and equations
-Worked Example
You can find also more at:
http://hassanelbanhawi.com/staticequipment/firedequipment/
All the data and the illustrative figures presented here can be found through two reference books:-
ENGINEERING DATA BOOK by Gas Processors Suppliers Association
Process Technology - Equipment and Systems by Charles E. Thomas
Thank you.
VULCAN Series VSG-Z101 Primary Reforming
Initial Catalyst Reduction
Activating (reducing) the catalyst involves changing the nickel oxide to nickel, represented by:
NiO + H2 <==========> Ni + H2O
Natural gas is typically used as the hydrogen source. When it is, the catalyst reduction and putting the reformer on-line are accompanied in the same step.
Energy saving in urea plant by modification in heat exchanger and processPrem Baboo
Energy is the prime mover of economic growth and is vital to the sustenance of a modern economy. Improvement in energy
efficiency reduces cost of production & results in environmental benefits, e.g. mitigation of global warming by way of less emission of
Green house gases in the atmosphere. Over the years several energy conservation measures have been taken towards reduction in
specific energy consumption and improvement in energy efficiency. The efforts’ resulted in reduction in specific energy consumption
from 6.27G. Cal/tone of Urea to 5.421 G.Cal/tone of Urea in 2015-16 as shown in the Graph No 1 & 2 with energy & down time.
Further a major modification of all plants is under way. Most of the schemes have been implemented in 2012 and the further
modifications expected to result again reduction of energy consumption for ammonia and Urea plants. This paper described some of
the modification in urea plants implemented recently in May/June 2016.
Calculation of an Ammonia Plant Energy Consumption: Gerard B. Hawkins
Calculation of an Ammonia Plant Energy Consumption:
Case Study: #06023300
Plant Note Book Series: PNBS-0602
CONTENTS
0 SCOPE
1 CALCULATION OF NATURAL GAS PROCESS FEED CONSUMPTION
2 CALCULATION OF NATURAL GAS PROCESS FUEL CONSUMPTION
3 CALCULATION OF NATURAL GAS CONSUMPTION FOR PILOT BURNERS OF FLARES
4 CALCULATION OF DEMIN. WATER FROM DEMIN. UNIT
5 CALCULATION OF DEMIN. WATER TO PACKAGE BOILERS
6 CALCULATION OF MP STEAM EXPORT
7 CALCULATION OF LP STEAM IMPORT
8 DETERMINATION OF ELECTRIC POWER CONSUMPTION
9 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT ISBL
10 ADJUSTMENT OF ELECTRIC POWER CONSUMPTION FOR TEST RUN CONDITIONS
11 CALCULATION OF AMMONIA SHARE IN MP STEAM CONSUMPTION IN UTILITIES
12 CALCULATION OF AMMONIA SHARE IN ELECTRIC POWER CONSUMPTION IN UTILITIES
13 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT OSBL
14 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT
Hydrogen recovery from purge gas(energy saving)Prem Baboo
Ammonia is continuously condensed out of the loop and fresh synthesis gas is added. Because the synthesis gas contains small quantities of methane and argon, these impurities build up in the loop and must be continuously purged to prevent them from exceeding a certain concentration. Although this purge stream can be used to supplement reformer fuel gas, it contains valuable hydrogen which is lost from the ammonia synthesis loop In order to achieve optimum conversion in synthesis convertor, it is necessary to purge a certain quantity of gas from synthesis loop so as to as to reduce inerts concentration in the loop. Purge gas stream from ammonia process contains ammonia, hydrogen, nitrogen and other inert gases. Among them, ammonia itself is the valuable product lost with the purge stream. Moreover it has a serious adverse effect on the environment.This purge gas containing about 60% Hydrogen was fully utilised as primary reformer fuel.
Furnaces in Refinery and Petrochemicals
Process furnaces
Crude distillation unit
Reaction Heaters
Reformer Heater
Heater Performance objectives
Reasons to save Energy
Heater Types
Radiant section
Convection section
Crossover section
Burners
In the plant, ammonia is produced from synthesis gas containing hydrogen and nitrogen in the ratio of approximately 3:1. Besides these components, the synthesis gas contains inert gases such as argon and methane to a limited extent. The source of H2 is demineralized water and the hydrocarbons in the natural gas. The source of N2 is the atmospheric air. The source of CO2 is the hydrocarbons in the natural gas feed. Product ammonia and CO2 is sent to urea plant. The present article intended the description of ammonia plant for natural gas based plants and the possible material balance of some section.
Fired Equipment presentation on Types, Classification and governing Equations...Hassan ElBanhawi
Based on my 8 years of experience in Oil & Gas industry I can claim that you can find here All what you need to know about Fired Equipment. This is an introduction to understand more about their:-
-Types
-Basic Principles and equations
-Worked Example
You can find also more at:
http://hassanelbanhawi.com/staticequipment/firedequipment/
All the data and the illustrative figures presented here can be found through two reference books:-
ENGINEERING DATA BOOK by Gas Processors Suppliers Association
Process Technology - Equipment and Systems by Charles E. Thomas
Thank you.
VULCAN Series VSG-Z101 Primary Reforming
Initial Catalyst Reduction
Activating (reducing) the catalyst involves changing the nickel oxide to nickel, represented by:
NiO + H2 <==========> Ni + H2O
Natural gas is typically used as the hydrogen source. When it is, the catalyst reduction and putting the reformer on-line are accompanied in the same step.
Brief introduction to Fired Heaters operation and design. Definition of the different Heaters in the industry and brief strategy how to operate them safely.
Centrifugal Compressors
SECTION ONE - ANTI-SURGE PROTECTION AND THROUGHPUT REGULATION
0 INTRODUCTION
1 SCOPE
2 MACHINE CHARACTERISTICS
2.1 Characteristics of a Single Compressor Stage
2.2 Characteristic of a Multiple Stage Having More
Than One Impeller
2.3 Use of Compressor Characteristics in Throughput
Regulation Schemes
3 MECHANISM AND EFFECTS OF SURGE
3.1 Basic Flow Instabilities
3.2 Occurrence of Surge
3.3 Intensity of Surge
3.4 Effects of Surge
3.5 Avoidance of Surge
3.6 Recovery from Surge
4 CONTROL SCHEMES INCLUDING SURGE PROTECTION
4.1 Output Control
4.2 Surge Protection
4.3 Surge Detection and Recovery
5 DYNAMIC CONSIDERATIONS
5.1 Interaction
5.2 Speed of Response of Antisurge Control System
6 SYSTEM EQUIPMENT SPECIFICATIONS
6.1 The Antisurge Control Valve
6.2 Non-return Valve
6.3 Pressure and flow measurement
6.4 Signal transmission
6.5 Controllers
7 TESTING
7.1 Determination of the Surge Line
7.2 Records
8 INLET GUIDE VANE UNITS
8.1 Application
8.2 Effect on Power Consumption of the Compressor
8.3 Effect of Gas Conditions, Properties and Contaminants
8.4 Aerodynamic Considerations
8.5 Control System Linearity
8.6 Actuator Specification
8.7 Avoidance of Surge
8.8 Features of Link Mechanisms
8.9 Limit Stops and Shear Links
APPENDICES
A LIST OF SYMBOLS AND PREFERRED UNITS
B WORKED EXAMPLE 1 COMPRESSOR WITH VARIABLE INLET PRESSURE AND VARIABLE GAS COMPOSITION
C WORKED EXAMPLE 2 A CONSTANT SPEED ~ STAGE COMPRESSOR WITH INTER-COOLING
D WORKED EXAMPLE 3 DYNAMIC RESPONSE OF THE ANTISURGE PROTECTION SYSTEM FOR A SERVICE AIR COMPRESSOR RUNNING AT CONSTANT SPEED
E EXAMPLE OF INLET GUIDE VANE REGULATION
FIGURES
2.1 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT DISCHARGE CONDITIONS
2.2 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT INLET CONDITIONS
2.3 PERFORMANCE CHARACTERISTICS OF A COMPRESSOR STAGE AT VARYING SPEEDS
2.4 SYSTEM WORKING POINT DEFINED BY INTERSECTION OF PROCESS AND COMPRESSOR CHARACTERISTICS
2.5 DISCHARGE THROTTLE REGULATION
2.6 BYPASS REGULATION
2.7 INLET THROTTLE REGULATION
2.8 INLET GUIDE VANE REGULATION
2.9 VARIABLE SPEED REGULATION
3.1 GAS PULSATION LEVELS FOR A CENTRIFUGAL COMPRESSOR
3.2 REPRESENTATION OF CYCLIC FLOW DURING SURGE OF LONG PERIOD
3.3 TYPICAL WAVEFORM OF DISCHARGE PRESSURE DURING SURGE
3.4 MULTIPLE SURGE LINE FOR A MULTISTAGE CENTRIFUGAL COMPRESSOR
3.5 TYPICAL MULTIPLE SURGE LINES FOR SINGLE STAGE AXIAL-FLOW COMPRESSOR
4.1 GENERAL SCHEMATIC FOR COMPRESSORS OPERATING IN PARALLEL TO FEED MULTIPLE USER PLANTS
4.2 ILLUSTRATION OF SAFETY MARGIN BETWEEN SURGE POINT AND SURGE PROTECTION POINT AT WHICH ANTISURGE SYSTEM IS ACTIVATED
4.3 ANTISURGE SYSTEM FOR COMPRESSOR WITH FLAT PERFO ..........
Fired Heaters-Key to Efficient Operation of Refineries and PetrochemicalsAshutosh Garg
Fired Heaters are a critical to successful operation of refineries and petrochemical plants. They are a major energy consumer as well as a major source of air pollution. There are also concerns about the run length of the heaters as well safety issues.
Process Heaters, Furnaces and Fired Heaters: Improving Efficiency and Reducin...Belilove Company-Engineers
A process heater is a direct-fired heat exchanger that uses the hot gases of combustion to raise the temperature of a feed owing through coils of tubes aligned throughout the heater. Depending on the use, these are also called furnaces or red heaters. Some heaters simply deliver the feed at a predetermined temperature to the next stage of the reaction process; others perform reactions on the feed while it travels through the tubes.
Super Critical Technology-Fundamental Concepts about Super Critical Technolog...Raghab Gorain
Nicely describe everything about super critical technology in thermal power plant.This slide is very useful for the freshers.Anybody can get the basic fundamental idea about super critical technology from this slide. In India now we have to think some new technology for power sources as sub critical power plants are less efficient and emit more pollutant to the environment and the alternative is the 'Super Critical Power Plant'.
Why have a Secondary Reformer ?
Need nitrogen to make ammonia
Wish to make primary as small as possible
Wish to minimise methane slip since methane is an inert in the ammonia synthesis loop
Other methods of achieving this
Braun Purifier process
Can address all these with an air blown secondary
Brief introduction to Fired Heaters operation and design. Definition of the different Heaters in the industry and brief strategy how to operate them safely.
Centrifugal Compressors
SECTION ONE - ANTI-SURGE PROTECTION AND THROUGHPUT REGULATION
0 INTRODUCTION
1 SCOPE
2 MACHINE CHARACTERISTICS
2.1 Characteristics of a Single Compressor Stage
2.2 Characteristic of a Multiple Stage Having More
Than One Impeller
2.3 Use of Compressor Characteristics in Throughput
Regulation Schemes
3 MECHANISM AND EFFECTS OF SURGE
3.1 Basic Flow Instabilities
3.2 Occurrence of Surge
3.3 Intensity of Surge
3.4 Effects of Surge
3.5 Avoidance of Surge
3.6 Recovery from Surge
4 CONTROL SCHEMES INCLUDING SURGE PROTECTION
4.1 Output Control
4.2 Surge Protection
4.3 Surge Detection and Recovery
5 DYNAMIC CONSIDERATIONS
5.1 Interaction
5.2 Speed of Response of Antisurge Control System
6 SYSTEM EQUIPMENT SPECIFICATIONS
6.1 The Antisurge Control Valve
6.2 Non-return Valve
6.3 Pressure and flow measurement
6.4 Signal transmission
6.5 Controllers
7 TESTING
7.1 Determination of the Surge Line
7.2 Records
8 INLET GUIDE VANE UNITS
8.1 Application
8.2 Effect on Power Consumption of the Compressor
8.3 Effect of Gas Conditions, Properties and Contaminants
8.4 Aerodynamic Considerations
8.5 Control System Linearity
8.6 Actuator Specification
8.7 Avoidance of Surge
8.8 Features of Link Mechanisms
8.9 Limit Stops and Shear Links
APPENDICES
A LIST OF SYMBOLS AND PREFERRED UNITS
B WORKED EXAMPLE 1 COMPRESSOR WITH VARIABLE INLET PRESSURE AND VARIABLE GAS COMPOSITION
C WORKED EXAMPLE 2 A CONSTANT SPEED ~ STAGE COMPRESSOR WITH INTER-COOLING
D WORKED EXAMPLE 3 DYNAMIC RESPONSE OF THE ANTISURGE PROTECTION SYSTEM FOR A SERVICE AIR COMPRESSOR RUNNING AT CONSTANT SPEED
E EXAMPLE OF INLET GUIDE VANE REGULATION
FIGURES
2.1 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT DISCHARGE CONDITIONS
2.2 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT INLET CONDITIONS
2.3 PERFORMANCE CHARACTERISTICS OF A COMPRESSOR STAGE AT VARYING SPEEDS
2.4 SYSTEM WORKING POINT DEFINED BY INTERSECTION OF PROCESS AND COMPRESSOR CHARACTERISTICS
2.5 DISCHARGE THROTTLE REGULATION
2.6 BYPASS REGULATION
2.7 INLET THROTTLE REGULATION
2.8 INLET GUIDE VANE REGULATION
2.9 VARIABLE SPEED REGULATION
3.1 GAS PULSATION LEVELS FOR A CENTRIFUGAL COMPRESSOR
3.2 REPRESENTATION OF CYCLIC FLOW DURING SURGE OF LONG PERIOD
3.3 TYPICAL WAVEFORM OF DISCHARGE PRESSURE DURING SURGE
3.4 MULTIPLE SURGE LINE FOR A MULTISTAGE CENTRIFUGAL COMPRESSOR
3.5 TYPICAL MULTIPLE SURGE LINES FOR SINGLE STAGE AXIAL-FLOW COMPRESSOR
4.1 GENERAL SCHEMATIC FOR COMPRESSORS OPERATING IN PARALLEL TO FEED MULTIPLE USER PLANTS
4.2 ILLUSTRATION OF SAFETY MARGIN BETWEEN SURGE POINT AND SURGE PROTECTION POINT AT WHICH ANTISURGE SYSTEM IS ACTIVATED
4.3 ANTISURGE SYSTEM FOR COMPRESSOR WITH FLAT PERFO ..........
Fired Heaters-Key to Efficient Operation of Refineries and PetrochemicalsAshutosh Garg
Fired Heaters are a critical to successful operation of refineries and petrochemical plants. They are a major energy consumer as well as a major source of air pollution. There are also concerns about the run length of the heaters as well safety issues.
Process Heaters, Furnaces and Fired Heaters: Improving Efficiency and Reducin...Belilove Company-Engineers
A process heater is a direct-fired heat exchanger that uses the hot gases of combustion to raise the temperature of a feed owing through coils of tubes aligned throughout the heater. Depending on the use, these are also called furnaces or red heaters. Some heaters simply deliver the feed at a predetermined temperature to the next stage of the reaction process; others perform reactions on the feed while it travels through the tubes.
Super Critical Technology-Fundamental Concepts about Super Critical Technolog...Raghab Gorain
Nicely describe everything about super critical technology in thermal power plant.This slide is very useful for the freshers.Anybody can get the basic fundamental idea about super critical technology from this slide. In India now we have to think some new technology for power sources as sub critical power plants are less efficient and emit more pollutant to the environment and the alternative is the 'Super Critical Power Plant'.
Why have a Secondary Reformer ?
Need nitrogen to make ammonia
Wish to make primary as small as possible
Wish to minimise methane slip since methane is an inert in the ammonia synthesis loop
Other methods of achieving this
Braun Purifier process
Can address all these with an air blown secondary
Energy saving and pollution control in urea plant though prilling tower and o...Prem Baboo
In Prilling Tower the ambient air is used as the cooling air stream for this process. In hot days, the temperature of the product at the bottom of the tower are hot that cannot be packed directly.Prilling tower have variable opening louvers system, this helps to control air intake flow to prilling tower at bottom, which is very useful in rainy seasons as CRH (critical relative humidity) of urea becomes less than atmospheric humidity and prills tends to absorb moisture from air. Humidity of air along the height of tower increases due to evaporation of moisture from prills. Rate of change of humidity at the top is more than that at the bottom indicates most of the moisture is removed at the top when the prills is in the liquid stage. In addition, in hot/ humid days, the prills form lamps and cakes with each other. To overcome this problem the bulk flow cooler (BFC) or cooling fluidized dryer (CFD) are used.
A mathematical hydrodynamics, heat, and mass transfer between the urea and the cooling air is developed. The prilling tower is the source of pollution in form of dust and ammonia and that can be control by simple technic also energy saving in terms of ammonia saving, ammonia is the harmful pollutant if you vent and useful product if you recovers.
Latest steps taken to control air pollution Prem Baboo
There has been a "seven-fold increase" in Delhi's air pollution level since October 2015,
a Center for Science and Environment (CSE) expert said today even as real-time
exposure readings of nearly all monitoring stations put PM 2.5 and PM 10 figures above
the 'severe' threshold. Growing population of the city.
Advancement in neem oil extraction process Prem Baboo
This paper describes a process of preparation of neem oil water emulsion & coating of urea in fertilizer plants, at site of urea production. The neem tree found in Asia and basically Indian sub continent. The basic part for neem oil used is seed of the neem known as kernels .Different method are available to obtain neem oil including one new method Supercritical method for extraction of neem oil from kernels.Now a days the main demand of neem oil in fertilizers Industries for coating of Urea and other fertilizers. “Government of India has done away with the cap on neem- coated urea and now it can be produced 100%. It is a win-win situation for both industry and farmers. It has been noted that farmer’s income would increase with the help of neem-coated urea as productivity would increase with less usage of urea.”Consequently the demand of Neem oil drastically increasing. In this paper some description of oil preparation method. Using carbon dioxide: methanol for supercritical fluid extraction is the maximum yield eco friendly process but slightly economical.
A case study of thinning of ng (natural gas) injection line in mp section bef...Prem Baboo
In urea plant Medium pressure Inerts gases recover HRU burner in Captive Power Plant. The inserts containing useful fuel in the form of Hydrogen & Methane about 40-45% volume percentage of total inerts. This inerts also containing Oxygen because the passivation air is given in carbon Dioxide compressor suction line for passivation of Reactor vessel and all downstream Stainless Steel vessel. In the presence of Oxygen there are chances of explosive mixture of Hydrogen and Oxygen in exit of MP section final vent line, to overcome this dangerous situation natural gases are added in the MP section before MP condenser so that the range of explosive can be avoided. These gases Hydrogen & Methane come with carbon Dioxide gas from Ammonia plant, carbon Dioxide about 0.5-0.7 % and Methane about 0.08 to0.1%. But we have seen after implementation of this scheme, frequent leakage was observed from inlet flange as well as heavy erosion was noticed in the inside surface of vapour inlet line and flange. Erosion was noticed from NG injection point and extended downstream up to nozzle flange in elliptical pattern. Material of construction of the process piping is A312 TP -316 L (Cr-18%, Ni-12%, Mo-2.0%, N-0.2%, and C-0.03%) which is compliable as per basic licenser. Hence frequent thinning of the pipe wall nearing injection point is due to sudden expansion of natural gas. In order to minimize pipe wall erosion phenomenon near NG injection point an alternative arrangement of NG injection extending the 1” NG line up to center of the vapour inlet line has been implemented and location of injection also changed as fig.-3.
Coating particles or granules of urea with sulphur and a sealant results in the formation of a membrane that regulates the availability of nitrogen for plant growth.Sulphur Coated Urea (SCU) fertilizer is a slow-release fertilizer that is made by coating urea with sulphur and wax that increases nitrogen efficiency, improves plant growth and reduces water pollution, compared with water soluble fast-release urea. Sulphur Coated Urea Avoid soil compaction; reduce frequency of application and reducing total cost; effectively reduce salt index, improving quality of crops; sulphur is a middle element, to provide nutrition for crops. As a hi-tech controlled/slow release fertilizer, Sulphur coated urea (SCU) has both effects of nitrogen and sulphur fertilizers.
Cause and prevention for steam turbine blade scaling & fouling Prem Baboo
The paper intended to deposition of Wang scaling/deposition & corrosion on turbine blades. How to deposit these scales? Prevention and control the deposits. Major steam turbine problems causes and effects. Practical examples of our shut down experience of 40 ata & 100 ata steam turbines. Lab analysis detail report of wet steam cleaning and sand blasting cleaning of the blades.
Environment management and advanced waste treatment system in nitrogenious fe...Prem Baboo
The paper intended to the standpoint of harmful emissions typical nitrogen-based fertilizer plants producing ammonia and urea plants using the advanced available technologies. The critical emission points are established and analyzed. Several possible actions have been taken in order to minimize the emissions are presented.The method is low cost and at the same time enhances the fertilizer value of sewage sludge. It therefore has a large potential of competing with more established methods of sanitization.
Interphex2009 Advances In Bioreactor Modeling And ControlGregory McMillan
Presentation of kinetics, beta test results of wireless pH and temperature transmitters, and virtual plant study results on the effect of measurement resolution and time delay for bioreactor control
Super conversion in urea reactors with super cup high efficiency traysPrem Baboo
In Urea Conversion gas/liquid mixing in urea reactor with application of high efficiency trays homogeneous and heterogeneous phases’ iquilibria and kinetics is very important. The efficiency of Urea Reactors can be improved by the application of the latest generation of internals .Generally Fluid dynamics phenomenon are created by the concurrent gas liquid flow through the simple perforated trays which generates irregular bubbles now this problem has been solved by new generation high efficiency device super cup patented by M/S. Saipem. Present article intended how conversion increases by super cup with geometry of the shape of super cup etc. The increase in the efficiency has permitted direct benefits to the overall production and energy of the units, thus allowing lower energy consumption and a reduced environmental impact emission of greenhouse gases. The Super Cups can be applied to design a new generation of urea reactors as well as to improve the performance of existing equipment in a revamp design.
If the material of liner changed with 2RE 69 or Duplex material instead of SS316(urea grade), then passivation air can be reduced, resulting the energy saving because the inerts vented from M.P section and loss of ammonia and problem of pollution. To enhance capacity and energy of the existing plant the internals like vortex mixture and HET may be changed the capacity may increase up to 10-15%.HET, you can changed with super cup.The CO2 and feed top of the vortex mixture nozzle and Ammonia plus carbamate feed from side of the vortex mixture. In the mixing area the initial dispersion of gas and formation of liquid – gas mixture are performed.
High pressure vessel_leakage_in_urea_plants (1)Prem Baboo
In urea plant ammonium carbamate solution is very corrosive; all metals have corrosion problems with ammonium carbamate and the corrosion problems increase with temperature, a ten degree Celsius rise in temperature doubles the corrosion rate to the point where the duplex steel is no longer acceptable. The material plays a very important role in Urea plants. The space between the reactor liner and the shell is most often empty and employs various methods of detecting a leak ranging from conductivity measurements. Vacuum leak detection system, pressure leak detection system etc. Titanium, SS316L (urea grade), 2 RE-69 etc.) Over the years that can resist ammonium carbamate corrosion. Materials plays very important role in any industry. Selection of material is vital at design stage itself ,Wrong selection of material may lead to catastrophic failures and outage of plants & even loss of Human lives, Right selection of material leads to long life of plant. In the latest plants specialty duplex materials are used for liner. The actual reactor has been constructed using a variety of materials, e.g. Zirconium, Vessel inside a protective liner. This paper intended study of number of leakage in the HP loop vessels, e.g. Zirconium, Vessel inside a protective liner. This paper intended study of number of leakage in the HP loop vessels, e.g. Reactor, Stripper, Carbamate condenser etc. How to detect leakage and troubleshooting during detection and attending the leakages.
High pressure vessel leakage in urea plantsPrem Baboo
In urea plant ammonium carbamate solution is very corrosive; all metals have corrosion problems with ammonium carbamate and the corrosion problems increase with temperature, a ten degree Celsius rise in temperature doubles the corrosion rate to the point where the duplex steel is no longer acceptable. The material plays a very important role in Urea plants. The space between the reactor liner and the shell is most often empty and employs various methods of detecting a leak ranging from conductivity measurements. Vacuum leak detection system, pressure leak detection system etc. Titanium, SS316L (urea grade), 2 RE-69 etc.) Over the years that can resist ammonium carbamate corrosion. Materials plays very important role in any industry. Selection of material is vital at design stage itself ,Wrong selection of material may lead to catastrophic failures and outage of plants & even loss of Human lives, Right selection of material leads to long life of plant. In the latest plants specialty duplex materials are used for liner. The actual reactor has been constructed using a variety of materials, e.g. Zirconium, Vessel inside a protective liner. This paper intended study of number of leakage in the HP loop vessels, e.g. Zirconium, Vessel inside a protective liner. This paper intended study of number of leakage in the HP loop vessels, e.g. Reactor, Stripper, Carbamate condenser etc. How to detect leakage and troubleshooting during detection and attending the leakages.
Ureap lant energy improved with operation philosophyand reactor internalsPrem Baboo
The energy of H.P. loop directly proportional to the pressure of h.p loop. The H.P loop is the heart of urea plants. Conversion of urea depends upon N/C & H/C ratio, reactor internal construction, i.e. configuration of trays, reactants mixing phenomenon, flow pattern etc. other than pressure. In conventional plants there was too much pressure of the reactors for higher urea conversion. Now philosophy has been changed our mind concentrated on flow pattern of the fluid dynamics and internals of the reactors. The performances of Urea Reactors can be improved by the application of the latest generation of internals like HET, Vortex mixture and conversion booster. As a consequence, the HET & Vortex mixture can be applied to design a new generation of urea reactors as well as to improve the performance of existing equipment in a retrofit design. The increase in the efficiency has permitted direct benefits to the overall day-by-day performances of the units, thus allowing lower energy consumption and a reduced environmental impact. The present paper based on these facts and how to improve energy by changing internals, operational parameters like molar ratio, recycling of water in the system, pressure & temperature of the system to improve energy and equipment’s life. The most important of these consists of a sharp reduction in specific steam consumption. The fluid-dynamics of a urea reactor can be significantly improved by the introduction of the latest generation of internals. e.g. Super cup trays, Vortex mixture, NIIK internals, siphon jet trays etc. No pressure drop observed because the gas phase directly converted to liquid phase the driving force compensates the pressure drop and No load limitation.
The ppt discusses about the design of bubble and airlift bioreactor. It also deals with their application, advantages and disadvantages. Pictorial representation of bioreactors are provided for better understanding of the bioreactors. It helps to gain knowledge on the different type of bioreactors
The explosion hazard in urea process (1)Prem Baboo
In Urea plant passivation air is used in reactor, stripper and downstream of the all equipments. The reactor liner material used Titanium, Zirconium, SS 316L (urea grade), 2RE-69 and duplex material .except Titanium and Zirconium all stainless steel required more passivation air. In CO2 some quantity of Hydrogen is present about 0.14% to 0.2% . The passivation oxygen and Hydrogen makes explosive mixture. To avoid a fire or explosion in a process vessel is to introduce inert (noncombustible) gases in such a way that there is never a mixture with a combustible concentration in exit of MP vent. Mixtures of fuel, oxygen, and inert gases are not combustible over the entire range of composition. In CO2 stripping process the HP scrubber is the risky vessel and this vessel consisting blanketing sphere, Heat exchanger part and a scrubbing part. With help of triangular diagram that shows the shape of the combustible/noncombustible regions for a typical gaseous mixture of fuel, oxygen, and inert at specified temperature and pressure. Present article how to avoid that combustible rang and how to tackle that gases in CO2 & ammonia stripping process.
Over the past two decades, the ammonia and urea industry have witnessed spectacular metallurgical developments for process equipment. For example, stainless steels, modified with special materials, can improve high temperature creep rupture resistance. Using duplex stainless steels and modern corrosion abatement techniques are other methods that improve plant-operating performance.
Ever since the declaration of 100% neem coated urea by India Government, the number of neem trees is increasing continuously in India Neem coated urea requires neem oil, more urea more oil and trees also required more. When it comes to oil, neem plants are rather promising. Probably no other plant yields as many exploitable by-products and benefits. Earlier, 100% Neem Coated Urea was made mandatory in 2015.
Prills /granular urea are not only costly for the producer but may be harmful to humans and the environment. Furthermore, nano Urea may also be used for enhancing abiotic stress tolerance. Nano-Urea prevents environmental pollution and improves physiological traits of wheat grown under drought stress conditions. The nano urea consist of higher surface area because lesser in size of the nano particle and have high reactivity, solubility in water. Nano Urea are the important tools in agriculture to improve crop efficiency, yield and quality parameters with increase nutrient use efficiency, reduce wastage of fertilizers and cost of cultivation. Nano-urea is very effective for precise nutrient management in precision agriculture with matching the crop growth stage for nutrient and may provide nutrient throughout the crop growth period. Nano-Urea increase crop growth up to optimum concentrations further increase in concentration may inhibit the crop growth due to the toxicity of nutrient. Nano-Urea provide more surface area for different metabolic reactions in the plant which increase rate of photosynthesis and produce more dry matter and yield of the crop. It is also prevent plant from different biotic and abiotic stress.
Installation of S-50 ammonia synthesis converter along with waste heat boiler in downstream of existing S-200 ammonia synthesis converter is one of the major schemes of Energy Saving Project of Ammonia plant. The energy saving reported 0.18 G.Cal/T of Ammonia. Several ammonia plants have installed an additional ammonia synthesis converter in combination with a HP steam waste heat boiler, downstream of the existing ammonia converter. The result is increased conversion per pass, reduced compression requirements due to the smaller recycle gas stream, and improved waste heat recovery. Among the methodologies aimed at finding energy saving opportunities, pinch analysis linked to power and steam modeling has proved to be a powerful way for determining projects to improve the overall energy efficiency of industrial sites. This procedure has been applied successfully in many industrial facilities, allowing optimal energy recovery in the process and hence reduction of fuel consumption.
Sweet and sour experience of commissioning 1Prem Baboo
The paper describes a successful of plant start-up despite the pandemic difficulties and introduces a set of first considerations about the possible future application of available digital technologies for remote and distributed control system from central control room commissioning of complex Dangote Fertilizer Plants. The numbers of problem were faced during commissioning stage ultimately the 17th march 2021 was the historical date for achieved plant production of line-1 plant .The major problem was pandemic due to which scarcity of staff availability. However numbers of problems faced in Ammonia and urea plants. About 4 time’s unsuccessful attempt were done and finally we got historical success. In this paper we described the failure attempt and types of problems faced in ammonia and urea plants and each time problems were differ from previous.
How to improve safety and reliability of the high pressure section of urea pl...Prem Baboo
This paper elaborates the most critical safety hazards: Ruptures and toxic ammonia leaks. The paper also provides the Top 10 prevention and mitigation measures. To minimize / avoid that incidents do repeat, we recommend to make use of the Center for Chemical Process Safety: Risk Based Process Safety Management approach. Pay proper attention to avoid ruptures, to handle leaks and to apply the right and state-of-the-art leak detection systems.
Experience of material in fertilizers industriesPrem Baboo
Materials plays very important role in any industry. Selection of material is vital at design stage itself ,Wrong selection of material may lead to catastrophic failures and outage of plants & even loss of Human lives, Right selection of material leads to long life of plant. In the latest plants specialty 2 RE-69 materials are used for liner. The actual reactor has been constructed using a variety of materials, e.g. Zirconium, Vessel inside a protective liner. This paper intended study Material in urea plant in different vessels and equipment design. In Primary reformer numbers of materials are modified such as micro alloy are also used in tubes.
This book covers design of high Pressure equipment and developments, Process flow diagram of different section of Ammonia, Urea and others fertilizers .Fundamentals of ammonia urea plant trouble shooting risk assessment corrosion in different vessels and remedies. This book is useful for Engineers and Sr. Managers for plant commissioning and trouble shooting and Engineering Students. This book contains about 51 tables and 144 useful diagram and chart graphics etc. Detail description of ammonia/CO2 stripping process and new developments. Design Parameters of High pressure vessel and comparison. Study of corrosion for various equipments and control. How to control corrosion by changing of equipments material.
2018 11 baboo the analysis and prevention of safety hazards in nfl complexPrem Baboo
The success of any industries lies its efficient working which in turn depends not only on equally and quantity of the service or product but also much on safe working. NFL is totally committed to conduct all its activities in harmony with society and nature without compromising on the health and safety of the employees as well as the people living around the complex. A full-fledged safety and environment protection department has been set up in the unit to achieve fulfillment of its statutory obligations concerning prevention of personal injuries, maintaining safe working conditions and protection of environment. For effective implementation of Safety, Health & Environment (SHE) policy, Each and every employee shall observe the safe system of work and follow proper safety work permit system while carrying out maintenance job inside the factory. This paper provides the detailed analysis of these hazards: In which plant sections and during which project phase do these safety hazards occur, which safety hazards occur most frequent and which hazards has the highest risk factor and troubleshooting case study and further improvement to learn these incidents
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Reactor kinetics & ; different types of reactor trays
1. REACTOR KINETICS &DIFFERENT TYPES OF
UREA REACTOR HIGH EFFICIENCY TRAYS
Author
Prem Baboo
Sr. Manager (Prod)
National fertilizers Ltd, India
Mob. +919425735974
prem.baboo@nfl.co.in ,pbaboo@hotmail.com
An Expert for www.ureaknowhow.com
Fellow of Institution of Engineers (India)
2. PURPOSE
1. The main purpose HET to improve the redistribution of unreacted carbon
dioxide inside the liquid phase rich in free ammonia.
2. To reduce the back mixing phenomenon due to density increase of carbamate
and urea solution from bottom to reactor top.
3. To reduce also channelling which has a negative effect on the solution residence
time.
ADVANTAGES
The activity contributes to environmental and social aspects and eventually to
sustainable development by: Reduction of consumption of non - renewable fuel like NG,
which is a step towards conserving natural resources. Reducing steam consumption
which results in reduction in energy consumption.
Steam is used in the strippers and varies proportionately with the urea production. Due
to the improved conversion efficiency of the process (again due to improved tray design
and increased number of trays), the steam utilisation in the overall manufacturing
process has reduced. Hence the parameter of the specific consumption of steam to urea
gives a clear indication of the energy saved. As elaborated above, the specific
consumption of the steam to urea forms the critical parameter and hence the urea
production and accordingly the steam consumptions are monitored.
Fig.-1
A typical reactor therefore contains a gaseous phase and a liquid phase flowing in co-current
flows inside a pressurized reaction chamber. Conversion of ammonia and carbon dioxide to
ammonium carbonate and ultimately urea is enhanced as fig-1, i.e. to increase urea output,
using tray reactors. Urea tray reactors substantially comprise a normally cylindrical shell, which
3. extends substantially along a normally vertical axis, and is fitted inside with elements, i.e. trays,
defined by respective metal sections shaped and/or perforated to divide the reaction chamber
into compartments and form specific paths for the substances inside the reactor. The trays are
normally perpendicular to the vertical axis of the reactor, and equally spaced along the axis to
the full height of the reactor. The trays are very often perforated, i.e. have holes variously
arranged and possibly of different shapes and/or sizes. Fluid dynamics and its influence on
heat and mass transport rates in gas–liquid reactors is, in general, an important starting
point for development of a process design. Improvements in the understanding of these
aspects can be particularly fruitful in the case of urea reactors where the fluid-dynamic
patterns are complicated by the co-current flow of two phases and the bubbling mode of
the vapours. The analysis of such systems highlighted the non-optimal design of existing
reactors and led to the conception of new reactor internals. Several industrial
applications demonstrate the ability of the new configuration to improve reactor
efficiency. Both energy-saving and production increases were obtained. This is a further
demonstration that even mature technologies can be improved, leading not only to
economic advantages, but also to a reduction in their environmental impact. With
CO2conversion in the reactor ranging from 56 to 70%, depending on the particular
technology adopted, efforts to obtain improvements have mostly been addressed to the
recycle system. The efficiency of the synthesis reactor itself has been particularly under
evaluated, probably following the common conviction that the optimum performance
had already been achieved. Urea reactors consist of cylindrical vessels (generally 20–40
m high), having diameters from 1 to 3 m, containing, in most cases, several trays
giving rise to a stage-wise structure. The aim is to reduce axial back mixing and
redistribute the vapour phase. Some-times, reactors operating at high NH3/CO2 ratios
and pressures, and having relatively small diameters, are used without trays. In the
most widespread process configurations, the unconverted reactants are recycled to the
reactor through a series of decreasing pressure stages using heat provided by steam.
The higher the CO2 conversion, the smaller the amount of heat and the size of the
equipment needed to reach a certain capacity. During the formation of urea, vapour
and liquid are present all along the reactor, flowing co-
Currently and exchanging mass and enthalpy fluxes through their interfaces. As the
process is also characterized by reversible reactions, the overall behaviour is
controlled by both physical and chemical equilibrium, coupled with physical and
chemical kinetics.
The trays are preferably designed for insertion through the manhole reactors are
normally provided with, so they can also be fitted to existing reactors and/or removed
and replaced. For which reason, the trays are normally made in a number of parts that
fit together.
The trays have various functions, and in particular:
1. Maximize the hold time of the light (faster) phase; distribute the reactants as
evenly as possible along the reactor section, to prevent back-mixing’;
4. 2. Enhance mixing of the gaseous- and liquid phases; and
3. Reduce bubble size' to improve diffusion of the ammonia in the carbon dioxide.
Numerous urea reactor tray designs and configurations are known.
The Principle of high efficiency trays:-
1. Mass transfer factor
2. Contact pattern of phase
3. Fluid dynamics factors
4. Interfacial surface area
5. Geometry of reactor vessel
6. Chemical kinetics factors
7. Temperature & pressure
Generally speaking, known solutions fail to provide for thorough mixing of the light
and heavy phases (both consisting of supercritical fluids) , which, because of the
difference in density, tend to flow along separate preferential paths defined by the
design and arrangement of the trays, and in particular by the shape, location, and
size of the holes in the trays. This drawback also impairs final conversion of the
reactants, thus reducing urea output.
1. The geometry of the reactor tray according to the present invention provides for
thoroughly mixing the gaseous and liquid phases in a urea reactor and urea
production process, and so greatly increasing urea output.
2. The reactor tray according to the present invention and the reactor as a whole
are also extremely easy to produce and install.
3. Urea producers can reduce consumption and/or increase production of their
plants by introducing the various revamping technologies developed
The installation high efficiency trays are giving an increased production of urea and
reduced steam consumption; the financial benefits are determined by the urea sales and
energy prices. It has been demonstrated that the installation of high efficiency reactor
trays in existing urea plant is very profitable.
THE USE OF REACTION KINETICS TOIMPROVE THE CONVERSION IN
VERTICAL UREAREACTORS
The conversion of Carbamate into urea is a relatively slow reaction and requires heat.
Non converted ammonia and carbon dioxide, passing the high-pressure carbamate
condenser, supply the heat needed for this reaction. Because of the equilibrium
5. reaction, the reaction is preferably done in a plug flow type of reactor. Installing a
number of continuous stirred tank reactors in series can approach plug flow. Thus the
urea reactor is divided into a number of compartments, mostly separated with sieve
trays, and each compartment acts as a continuous stirred tank reactor. As a result plug
flow is approached in such a cascade type reactor.
Fig.-2(a) Fig.-2(b)
To obtain a continuous stirred tank reactor, stirrers should be applied. However urea
reactors are not equipped with mechanical stirrers. The driving force for mixing the
liquid in the compartments of the reactor is the gas phase. The urea reactor is a so-
called high-pressure bubble column. By adding the gas phase through the center of a
compartment via carefully designed holes, a Torus circulation exists and thus the
required mixing of the liquid in such a compartment is obtained, as fig. 2(a) the
principle of such a Torus circulation exists and thus the required mixing of the liquid in
such a way Compartments obtained. The principle of such a torus circulation is shown
in the figure.Because the urea reaction is a relatively slow equilibrium reaction a
relative large retention time in the reactor is needed to approach the maximum
equilibrium level. Fig.-3, However an infinite large reactor volume is required to reach
this equilibrium. For economic reasons the installed reactor volume in the designing of
urea plants is such that the fraction approach to equilibrium (FAE) is 95 percent. The
fraction approach to equilibrium is defined as:
FAE = 100* ήC02 actual/ ή C02 equilibrium
Fig.-3
Retention
F.A.E
ή co2
6. The relation between the fraction approach to equilibrium and the retention is shown in Fig.
In large-scale urea plants (> 1500 MTPD), equipped with reactors with large diameters and
conventional type reactor trays, it is observed that the expected fraction approach to
equilibrium is not reached resulting in a relative low reactor conversion. The consequence is
that at a specified plant capacity the steam consumption on the high-pressure stripper is
larger than expected. The reason for the observed relative low reactor conversion was a
non-optimal mixing rate in the urea reactor compartments and, thus, these compartments
did not act as an optimal continuous stirred tank reactor. The non-optimal mixing behavior
in such reactors can be caused by:
1. Back mixing
2. Channeling (fig-5,a)
3. Stagnant zones
Back mixing occurs when the liquid phase passes the sieve trays through the gas holes. This
occurs when the height of the gas cushion below the sieve tray is small. In reactors with large
diameters, when the reactor tray is not perfectly horizontal then the
. gas holes are in contact with the liquid phase. This is illustrated in
Fig.-4
Reactors with a relative large diameter are sensitive for stagnant zones. Stagnant zones
are caused by poor mixing in the compartments and have a negative impact on the
reactor conversion since the compartments will not optimally act as the required
continuous stirred tank reactor. To avoid the negative effects of back mixing and
channeling, Stamicarbon developed in the beginning of the 90’s the high efficiency trays
as illustrated in the fig.
Channeling occurs when the liquid phase is partly bypassing a compartment. In urea
reactors, equipped with conventional sieve trays, the liquid is transported from the one
compartment to the other compartment via the annular spacing between the tray and
the reactor wall. In urea reactors with large diameters it appears that the mixing rate by
7. the Torus circulation may not be large enough to avoid these channeling effects. The
channeling effect is shown in Fig.
Fig.-5(a) Fig-5(b)
HIGH EFFICIENCY TRAYS, HET
These high efficiency reactor trays are equipped with liquid risers where the liquid
enters the following compartment. By staggering the liquid risers, the liquid is forced
into the Torus circulation and channeling is eliminated. To avoid back mixing, the gas
cushions were increased and this makes the trays less sensitive to horizontal variations
of the tray. Because the conversion of carbamate into urea is an equilibrium reaction,
the reaction is preferably done in a plug flow type of reactor; that is to say, one in which
the flow of reaction medium is uniform and non-turbulent over the entire cross-section
of the reactor interior. It is difficult to prevent turbulence and back mixing in a large
unconfined body of fluid; however, an approximation to overall plug flow can be
attained in a number of continuous stirred tank reactors arranged in series. Therefore
the urea reactor is divided into a number of compartments, separated from one another
by sieve trays, and each compartment emulates a continuously-stirred tank reactor. The
driving force for mixing the liquid in the compartments of the reactor is the gas phase.
By forcing the gas phase to pass through the centre of a compartment via carefully
designed holes, a Torus-shaped circulation prevails and thus the required mixing of the
liquid in such a compartment is obtained. However, in larger reactors non-optimal
mixing behaviour has been identified and investigated. Identified causes were back
mixing, channelling and stagnant zones. To address that problem, Stamicarbon has
developed a new generation of high efficiency trays known as Siphon Jet Pump trays.
The compartments, separated by sieve trays, are equipped with a draft tube. Inside the
draft tube there is a two-phase flow of gas and liquid. The effective density of this two-
phase flow is considerably lower than the liquid density on the outside of the draft tube,
and the density difference further enhances liquid circulation, promoting mixing. The
deflector plates in the pool reactor and pool condenser, which work on the same
principle as the draft tube, have amply proved this effect. Using Siphon Jet Pump trays
provides the closest approach to a continuous stirred tank reactor without necessitating
8. any mechanical agitation. The mixing rate is increased significantly and the negative
effects of back-mixing and channelling are avoided. The first Siphon Jet Pump trays
were installed at SKW Piesteritz, and the result was so satisfactory that Siphon Jet
Pumps have been installed in all three plants and are currently in operation. They have
had the effect not only of making operations very smooth and raising the capacity of the
existing plants, but also of reducing the HP steam requirement of the HP stripper.
Amongst others, Fauji Pakistan, ABF Malaysia and Qafco Qatar have also installed iphon
Jet Pumps in their
Although the high efficiency trays 'improved the reactor efficiency significantly, they did
not improve the mixing rate. The mixing is still reliant upon the Torus circulation. In
practice it appeared to be difficult to keep the strict tolerances for the gap between the
reactor tray and the reactor wall because of the no roundness of the reactor. To improve
the mixing rate in the reactor compartment sand to avoid strict Mechanical tolerances,
Stamicarbon recently developed a new generation of H.E.T. Known as siphon jet pumps
Fig.-6
The compartments, separated by sieve trays, are equipped with a draft tube. Inside
the draft tube there is a two-phase flow with the density of this two-phase flow
being considerably less than the liquid density at the outside of the draft tube. By
this density difference liquid circulation is enhanced further stimulating the
mixing. The deflector plates in the pool reactor and pool condenser, in which the
deflector plates have a similar function as the proposed draft tube, have proved
these phenomena
9. Because of this heavy circulation effect and thus improved mixing rate it is no
longer necessary to equip the reactor trays with liquid risers. The liquid can
enter the following Compartment via the annular spacing between the tray and
the reactor wall in a similar fashion as the conventional Reactor trays. The strict
tolerance regarding the gap between The tray and the reactor wall for the new
generation HET is No longer required
The first Siphon Jet Pumps were installed in one of the plants of SKW Piesteritz.
Because the trays were operating very satisfactory, two other reactors of SKW
Piesteritz are now also operating with Siphon Jet Pumps. In the following table
the current references for Siphon Jet Pumps are presented.
Table-1
Client
Capacity Year in Number of New/Modified
(MTPD) operation trays trays
SKW Piesteritz 3 1050 2001 11 New
SKW Piesteritz 1 1050 2002 11 New
SKW Piesteritz 2 1050 2003 11 New
Fauji Fert.Pakistan 1670 Completed
in
2004
10 Modified
ABF Malaysia 2250 Completed
in 2004
11 New
Qafco II 1400 Completed
in 2005
11 New
Daqing 2300 Completed
in 2005
11 New
Qafco III 3000 Completed 11 New
The gas holes in the tray are more centered than in the conventional tray design to
improve the driving force and the tray is equipped with a ring that acts as a Venturi to
improve the mixing rate,as fi 8 & 9.By installing these siphon jet pumps all aspects to
approach the continuous stirred tank reactor are included. The mixing rate is increased
significantly and the negative effects of back mixing and channeling are avoided.
10. Fig.-7
CASALE TRAYS
Fig.-8
1. Inverted ‘U’ type , better mixing due to generation of smaller bubbles
increasing interfacial surface area and improving the contact pattern causing
higher CO2 conversion
F.A.E.
A- convention trays
B- high eff. Trays
C -Siphon jet pump
11. Fig.-9
2. Small perforation at top and sloping area for vapour space and large perforation
for liquid at bottom area
3. But CASALE trays suffers from corrosion due to sharp configuration
Fig.-10
In combination with other Casale technologies such as the High Efficiency Trays, the
Split Flow Loop/ Full Condenser configuration is applied for increasing the capacity of
CO2 stripping plant with very low investment.
High Efficiency reactor trays, the HP loop is drastically debottlenecked even for a large
capacity increase (Up to 50% over its original design. Casale, therefore, foresaw to
install the Casale Dente High Efficiency Trays in order to debottleneck the HP synthesis
section.
12. TABLE.-2 - Plant performance after Casale trays installation
Plants Country Year Process No. of
Trays
CO2 conversion
Increase(%points)
MP Steam
Consumption
reduction(kg/MT)
Capacity
increase
(%)
Togliatti
Azot
Russia 1993 NH3
Stripping
14 6.4 300 17
Togliatti
Azot
Russia 1993 NH3
Stripping
14 4 200 17
Arcadian Trinidad 1994 NH3
Stripping
14 2.8 183 9
Yuman
Chem(*)
China 1994 CO2
Stripping
10 3.5 148 3
Agrium
Can
Canada 1994 CO2
Stripping
10 5 65 -
Chemco Bulgaria 1995 NH3
Stripping
14 NA 170 6
CFI(**) USA 1995 CO2
Stripping
10 3.5 70 10
Agrium
USA
USA 1995 NH3
Stripping
10 5.3 251 9
Amonil Romania 1996 CO2
Stripping
11 5 178 8
NFCL India 1996 NH3
Stripping
14 4.5 95 3
Shriram India 1996 Total
Recycle
14 6 >100 -
NFL,Nangal India 2001 Montedition 14 6 110 6
Note.-(*) only 5 HET installed
(**) Data after trays installation based on Casale Survey
Casale has been, in the last decades, very active in revamping existing plant and has
extensive experience in the design and implementation of complete plant revamping
projects, including major modifications to key equipment. Casale’s plant revamp
strategy has always been to develop and apply new, advanced technologies to obtain the
best possible improvement in plant performance at the minimum cost; with the aim of
reducing the energy consumption and/or increasing the capacity
The Casale-Dente High Efficiency Trays (HET) are the most efficient trays available on
the market and are also an essential element in making the Split-Flow-Loop as efficient
as it is. The improved geometry of these trays has a profoundly beneficial effect on the
mass transfer efficiency of NH3 and CO2 from the vapours into the liquid phase where
urea is formed.
The new trays are designed in such a way that: · Vapours and liquid follow separate, but
adjacent cocurrent paths through the space between the trays. This guarantees stable
flow of the two phases and a better approach to an even uniform flow of the two phases
throughout the whole reactor. · These separated paths through the tray are chosen so
that very efficient mixing takes place between vapour and liquid. Consequently there is
a very high degree of both mass and heat transfer within the liquid phase is realised. · It
is possible to generate vapour bubbles with a far smaller diameter than with any
previous design. As a consequence, the interfacial surface, for mass and heat transfer, is
increased. · There is also a much larger interfacial surface for exchange between the
13. vapour bubble emulsion and clean liquid. · The relative short path length of the
recirculation streams into the emulsion phase significantly decreases transfer
resistances. The trays are plates corrugated into a series of parallel linear ridges and
troughs. The ridges are flattened at the top and the troughs are similarly flattened at the
bottom. Large perforations are provided in the trough bottoms for liquid to pass
through and there are small perforations in the tops of the ridges for gases
accumulating beneath them to pass This unique design produces extremely small
bubbles and, as a consequence, a very high specific surface area for mass and heat
transfer enhancing the highly efficient mixing between vapours and liquid mentioned
above.
SNAMPROGETTI (SAIPEM) SUPERCUPS TRAYS
1. The innovative M/S. Saipem Super Cups design for Urea reactor trays has been
conceived and developed by Saipem with the support of Engin Soft by means of
CFD(Computation Fluid dynamics) simulation. Latest super cup trays the third
generation of high efficiency trays recently invented and patented by Saipem
2. Computational Fluid Dynamics (CFD) provides a qualitative (and sometimes even
quantitative) prediction of fluid flows by means of mathematical modelling (partial
differential equations)
3. The computer code (software) which embodies this knowledge and provides detailed
instructions (algorithms) for the computer hardware which performs the actual
calculations. CFD is a highly interdisciplinary research area which lies at the interface of
fluid dynamics.
4. The Reactor trays that prevent back-flow of the heavier solution from the upper
part downwards and favour the gas absorption in the liquid phase.
5. The support of a systematic plan of fluid-dynamic simulations gave a significant
contribution to the development of the innovative design.
6. The proprietary M/S Saipem Super Cups (“New Design”) greatly increases the
mixing of the liquid and gaseous phases, respectively ammonia and carbamate, and
carbon dioxide, thus optimizing the product conversion rate in the reactor. The
immediate benefit is the lower specific steam consumption requirement to
decompose carbamate to CO2 and NH3 in downstream sections.
7. This represents a further step ahead to get closest to the theoretical equilibrium
conversion in the reactor. In fact, the increase in the reaction conversion is strictly
dependent on the mixing conditions of ammonia, carbamate and carbon dioxide
through the reactor so that the main purpose of these innovative trays is to further
improve the contacting conditions among the reagents.
8. The peculiar behaviour of the Super Cups is characterized by a triple fluid-dynamic
effect – Gas Equalizer, Mixer Reactor and Gas Distributor.
9. The first effect of Super Cups is to uniformly distribute the concentration of the
gaseous phase reagent on the entire section of the tray. In this way, the gas bubbles
moving upward “lose the memory” of the non-uniformity of the previous reaction
stage and the non-reacted CO2 can be evenly fed to each cup of the tray. Figure
shows the formation of the “gas-cushion” (blue area) just below the tray externally
to the cups. The cups behave as multiple confined reaction volumes in which the
14. reagents - gaseous CO2 and liquid ammonia & carbamate – heavily swirl inside,
thus reaching a high mixing degree. Each cup performs as a static mixer where the
phases are strongly contacted.
10. In this way the Super Cups Trays do not simply behave as gas distributors – as in
other commercial designs. But perform as additional active reaction stages which
can be modelled as a Continuous-Stirred-Tank Reactor (“CSTR”),as fig 12. The
CSTR behaviour (ideal perfect mixing) of each single tray can be clearly observed
by the comparison of RTD curves for the new and standard designs.
11. The mean residence time increases by about 70% with respect to the standard
design, thus strongly improving the urea formation yield.
12. The CO2 gaseous phase forming the gas-cushion below the tray can be partially
streamed inside the cups to create a mixer reactor and partially distributed on the
upper stage. This split range is one of the most critical design parameter since it
allows the customization of the RTD curve of each reactor stage and the increase or
decrease of the CSTR (perfect mixing) or PFR (plug flow) behaviour according to
the composition of each stage.
13. The Super Cups Trays permit an increase in the urea reactor efficiency with
consequent beneficial effects in terms of higher return on investment, lower
energy consumptions and reduced environmental impact.
14. The CFD study of the traditional perforated plate vs. the innovative tray facilitated
the ability to compare the fluid dynamic behaviour of several designs in terms of
mixing performance of the reactants, flow patterns, pressure drops and residence
time.
Fig.-11
16. CONCLUSIONS
With the combination of skilful modelling and original design, the possibility was
proven of increasing the efficiency of urea reactors, which were considered for a long
time to be operating close to their optimum. This new tray design represents a
significant upgrade of the urea reactors and, by consequence, of the whole plant. The
net improvement of the CO2 conversion in an existing plant has, in fact,
The following advantages:
1. The reduction of the energy consumption and of recycle.
2. The possibility of a sensible increase of the production with the same reactor.
The development and successful design of the High Efficiency trays in the reactor was
possible through a very accurate fluid dynamic simulation of the system combined with
the modelling of the chemical-physical equilibriums and of the heat transfer
phenomena. The most important of these consists of a sharp reduction in specific
steam consumption. This feature was con-firmed by a number of test run results
carried out in the field. Reductions of specific steam consumption up to 250–300 kg per
ton of urea have been obtained and capacity increases up to 10–20 % .
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