The document discusses using a multistage integrated chilling (MIC) scheme to increase ammonia production in ammonia plants. The MIC scheme thermally couples the process air compressor with the ammonia compression system. This allows increasing the process air compressor's throughput by up to 20% without modifications to compressors or drivers. Along with other measures like upgrading the synthesis loop, the MIC scheme can increase ammonia capacity by 12% and improve energy efficiency by 3 MMBtu/t without requiring changes to major equipment like compressors. The benefits of the MIC scheme include incremental increases in production and efficiency without major equipment upgrades or downtime.
This document summarizes the design of an air conditioning system for cooling the cabin of a truck using an air refrigeration cycle. The system uses a turbocharger and waste exhaust gases from the truck engine. Atmospheric air is compressed using the turbocharger and sent to an intercooler to reduce its temperature. It is then expanded in a turbo-expander to further lower its temperature before being supplied to the truck cabin. Thermodynamic and heat transfer analyses are presented to evaluate the performance of the system components and the cooling capacity. The results show that the air refrigeration cycle can provide enough cooling to lower the truck cabin temperature by 10-15°C without significantly impacting engine performance.
A Review Paper on Effects of Different Intake Manifold Designs on Diesel Engi...ijsrd.com
One of the objectives of car manufacturers is to improve engine performance, reduce consumption and reduce emissions. To achieve this objective, it is important to understand the phenomena involved in the combustion chambers of engines. There are various factors that influence the engine performance such as compression ratio, atomization of fuel, fuel injection pressure, and quality of fuel, combustion rate, air fuel ratio, intake temperature and pressure and also based on piston design, inlet manifold, and combustion chamber designs etc. Geometrical design of intake manifold is one such method for the better performance of an I.C. Engine. Air swirl motion in CI engine influences the atomization and distribution of fuel injected in the combustion chamber. Intake manifolds provides Air motion to the chamber. So, to get the maximum output with the least input on Diesel engine researchers are experimentally and computationally working on construction of the intake manifold configurations for increase in engine performance and reduction of Exhaust Emissions. In this paper i have studied few papers and also gone through basics of my topic from various books to understand the phenomena.
This document summarizes an innovative internal combustion engine concept for UAV applications. The engine uses stratified charge combustion with rich and lean zones to improve efficiency. It also incorporates a turbo compound configuration with multiple expansion stages to recover exhaust energy. Initial CFD analysis shows the stratified combustion and scavenging processes work as intended. The concept could enable high efficiency engines across a wide range of sizes, from 100 HP automotive engines to 7000 HP engines for UAVs.
Reducing ac power consumption by compressor downsizing on a sportArun Prakash
This document discusses reducing air conditioning (AC) power consumption in vehicles by downsizing the AC compressor. It describes testing conducted on a sports utility vehicle (SUV) originally equipped with a 170 cc/rev reciprocating piston compressor. The study involved experimentally evaluating three compressors: 1) the original 170 cc compressor, 2) a 130 cc reciprocating compressor, and 3) a 90 cc rotary scroll compressor. The compressors were tested at the component, system, and vehicle levels. Results showed the 130 cc compressor reduced power consumption by 5-18% compared to the 170 cc compressor at the component level. At the system level, the 130 cc compressor maintained equivalent cooling to the 170 cc compressor after optimizing other system components
This document discusses the implementation of Total Productive Maintenance (TPM) on a boiler. It begins with background on boilers, describing the two main types - smoke tube boilers and water tube boilers. It then provides an overview of TPM, including its goals of preventing unexpected failures through preventive and predictive maintenance. The document outlines the five pillars of TPM implementation: autonomous maintenance, planned maintenance, maintenance reduction, quality maintenance, and education and training. It concludes with the nine essentials of a successful TPM program.
This document provides an introduction to boiler control systems engineering. It begins with an overview of basic boiler components such as the furnace, fans, heat exchangers, drums and piping. It then discusses common control strategies for boilers like feedback control, feedforward control and cascade control. The document provides details on tuning PID controllers and determining control parameters. It is intended to help anyone working with boiler control systems understand the engineering of boiler controls.
This document summarizes research on modeling and experimentally analyzing a generator for a vapor absorption refrigeration system. The researchers designed a prototype system using heat from exhaust gases to vaporize an ammonia-water working fluid in a plate heat exchanger generator, replacing a heating coil generator typically used. They analyzed the available heat in exhaust gases from an internal combustion engine and modeled the plate heat exchanger. The document describes the components and working of an ammonia-water vapor absorption refrigeration system, specifications of the internal combustion engine used, design calculations for the plate generator, and presents conclusions on utilizing exhaust heat and further modeling needed.
This document summarizes the design of an air conditioning system for cooling the cabin of a truck using an air refrigeration cycle. The system uses a turbocharger and waste exhaust gases from the truck engine. Atmospheric air is compressed using the turbocharger and sent to an intercooler to reduce its temperature. It is then expanded in a turbo-expander to further lower its temperature before being supplied to the truck cabin. Thermodynamic and heat transfer analyses are presented to evaluate the performance of the system components and the cooling capacity. The results show that the air refrigeration cycle can provide enough cooling to lower the truck cabin temperature by 10-15°C without significantly impacting engine performance.
A Review Paper on Effects of Different Intake Manifold Designs on Diesel Engi...ijsrd.com
One of the objectives of car manufacturers is to improve engine performance, reduce consumption and reduce emissions. To achieve this objective, it is important to understand the phenomena involved in the combustion chambers of engines. There are various factors that influence the engine performance such as compression ratio, atomization of fuel, fuel injection pressure, and quality of fuel, combustion rate, air fuel ratio, intake temperature and pressure and also based on piston design, inlet manifold, and combustion chamber designs etc. Geometrical design of intake manifold is one such method for the better performance of an I.C. Engine. Air swirl motion in CI engine influences the atomization and distribution of fuel injected in the combustion chamber. Intake manifolds provides Air motion to the chamber. So, to get the maximum output with the least input on Diesel engine researchers are experimentally and computationally working on construction of the intake manifold configurations for increase in engine performance and reduction of Exhaust Emissions. In this paper i have studied few papers and also gone through basics of my topic from various books to understand the phenomena.
This document summarizes an innovative internal combustion engine concept for UAV applications. The engine uses stratified charge combustion with rich and lean zones to improve efficiency. It also incorporates a turbo compound configuration with multiple expansion stages to recover exhaust energy. Initial CFD analysis shows the stratified combustion and scavenging processes work as intended. The concept could enable high efficiency engines across a wide range of sizes, from 100 HP automotive engines to 7000 HP engines for UAVs.
Reducing ac power consumption by compressor downsizing on a sportArun Prakash
This document discusses reducing air conditioning (AC) power consumption in vehicles by downsizing the AC compressor. It describes testing conducted on a sports utility vehicle (SUV) originally equipped with a 170 cc/rev reciprocating piston compressor. The study involved experimentally evaluating three compressors: 1) the original 170 cc compressor, 2) a 130 cc reciprocating compressor, and 3) a 90 cc rotary scroll compressor. The compressors were tested at the component, system, and vehicle levels. Results showed the 130 cc compressor reduced power consumption by 5-18% compared to the 170 cc compressor at the component level. At the system level, the 130 cc compressor maintained equivalent cooling to the 170 cc compressor after optimizing other system components
This document discusses the implementation of Total Productive Maintenance (TPM) on a boiler. It begins with background on boilers, describing the two main types - smoke tube boilers and water tube boilers. It then provides an overview of TPM, including its goals of preventing unexpected failures through preventive and predictive maintenance. The document outlines the five pillars of TPM implementation: autonomous maintenance, planned maintenance, maintenance reduction, quality maintenance, and education and training. It concludes with the nine essentials of a successful TPM program.
This document provides an introduction to boiler control systems engineering. It begins with an overview of basic boiler components such as the furnace, fans, heat exchangers, drums and piping. It then discusses common control strategies for boilers like feedback control, feedforward control and cascade control. The document provides details on tuning PID controllers and determining control parameters. It is intended to help anyone working with boiler control systems understand the engineering of boiler controls.
This document summarizes research on modeling and experimentally analyzing a generator for a vapor absorption refrigeration system. The researchers designed a prototype system using heat from exhaust gases to vaporize an ammonia-water working fluid in a plate heat exchanger generator, replacing a heating coil generator typically used. They analyzed the available heat in exhaust gases from an internal combustion engine and modeled the plate heat exchanger. The document describes the components and working of an ammonia-water vapor absorption refrigeration system, specifications of the internal combustion engine used, design calculations for the plate generator, and presents conclusions on utilizing exhaust heat and further modeling needed.
Review on Boiler Control Automation for Sugar IndustriesIRJET Journal
This document discusses boiler automation systems for sugar industries. It begins with an abstract that outlines controlling boiler parameters like steam generation and drum water level using PID controllers and SCADA systems. It then discusses several key boiler parameters that are controlled like drum level, pressures, temperatures, and flows. Upgrading to advanced automation controls is recommended to improve efficiency by minimizing excess air, allowing tighter emissions control, and improving combustion characterization. Automating the control of critical parameters can help ensure efficient and reliable plant operation.
This is a training module developed in the European project SESEC. More information and the full training can be found here: http://www.sesec-training.eu ...
The document discusses the basics of fuel injection systems in compression ignition (CI) engines. It outlines the key objectives of a fuel injection system which are to meter the correct amount of fuel demanded based on engine load and speed, distribute fuel equally among cylinders, inject fuel at the proper timing and rate, and ensure proper atomization. It also provides details on the typical injection timing window and angle. To achieve these objectives, the key functional components are identified as the pumping element to transport fuel, a metering element to control the fuel supply, a metering control to adjust the metering based on load/speed, and a distribution element to divide fuel evenly among cylinders. Finally, it lists some common types of fuel injection systems used in
An experimental investigation of engine coolant temperature on exhaust emissi...IAEME Publication
This document presents an experimental study on the effect of engine coolant temperature on exhaust emissions of a 3-cylinder, 4-stroke spark ignition engine. The study found that raising the coolant temperature in the engine block reduced hydrocarbon emissions, while lowering the coolant temperature in the cylinder head reduced nitrogen oxide emissions. Testing over coolant temperatures of 45-85°C and engine speeds of 1500-2400 rpm showed decreasing trends in hydrocarbon and nitrogen oxide emissions at higher coolant temperatures and engine loads. The results indicate that exhaust emissions are dependent on engine coolant temperature, with optimal temperatures existing for reducing different pollutants.
This document discusses fuel supply systems and air-fuel ratio requirements for spark ignition engines. It begins by describing the stages of the fuel supply system, including filtration, atomization and the need to finely disperse fuel before combustion. It then discusses the various fuel injection systems used in SI engines, including single-point/throttle body injection where fuel is injected into the throttle body, multi-point/port injection where each cylinder has a dedicated injector, and direct injection where fuel is injected directly into the combustion chamber. The document focuses on the air-fuel ratio requirements for SI engines under different operating conditions such as idling, cruising and high power, and explains why richer or leaner mixtures are needed depending on the situation.
This document provides an overview of fuel systems, including the main components and how they work. It compares carbureted and fuel injected systems, describing the different types of fuel injection. Electronic fuel injection uses sensors, actuators, and a computer to precisely meter fuel delivery. The computer receives feedback from oxygen sensors to continuously adjust the air-fuel ratio for optimal performance and emissions.
This document discusses the history of emissions control for engines, including the discovery of air pollution in Los Angeles in the 1940s. It then covers the introduction of HC and CO emission limits in 1966 which reduced emissions by 95% by the 1980s through more efficient engines and exhaust aftertreatment. The document also discusses the three methods used for emissions control: engineering combustion, optimizing operating parameters, and using aftertreatment devices like catalytic converters. It provides details on the anatomy and functioning of catalytic converters.
The document discusses various aspects of fuel injection systems, including:
1) It describes the basic components and operation of port fuel injection and throttle body injection systems, including the fuel pump, fuel pressure regulator, injectors, and how they are controlled by the computer.
2) It explains the different types of fuel injection systems and how they determine the proper fuel amount, such as speed density and mass air flow systems.
3) It provides diagrams and descriptions of the main components like the fuel rail, injectors, and pressure regulator and how they function within the fuel injection system.
The document discusses the fuel oil system on a locomotive engine. It describes the fuel feed system and fuel injection system.
The fuel feed system supplies fuel oil from the tank to the injection system at high pressure. It includes a primary filter, fuel pump, secondary filter, and fuel header piping. The fuel injection system atomizes and injects the fuel into the cylinders. It consists of high-pressure fuel injectors and fuel injection pumps that deliver fuel at precise timings and quantities. Proper functioning and testing of these systems is important for complete combustion and engine performance.
Review of theModern developments in Suction processes of IC EnginesIJERA Editor
This review paper deals with the evolution of the general processes employed in the suction process of IC
Engines. The suction process has evolved from the traditional use of carburettors to much more sophisticated
systems like CRDi, MPFi, etc. used in modern days. In doing so, various parameters such as the volumetric
efficiency and the turbulence, etc. inside the engine have to be considered. Additional processes such as
supercharging and turbocharging are employed to improve these parameters. It is also highly desirable to vary
the Air-Fuel ratio effectively according to the speed of the engine for better power output and mileage. Thus
researchers have developed several ways over the years to achieve it. Recent research work being carried out in
this field is in the areas of Pressure Wave Superchargers, Variable Geometry Turbochargers, Multiple Intake
valves, Shrouded Intake Valves, Camless Engines etc. Many of these technologies have been employed in the
industry such as the DTS-Si, TDi&i-vtec Engines. Thus, the Automobile Industry has come a long way in
evolving the intake processes and further developments will always be on the way.
This document summarizes the findings of an energy audit conducted at a textile mill in Tirupur, India. It identifies areas of high energy consumption and provides recommendations for improving energy efficiency. The major energy consuming systems identified are humidification plants, air compressors, and the motors used in carding, simplex, spinning, and auto coner departments. Recommendations include replacing old motors with high efficiency models, improving maintenance of humidification and air distribution systems to reduce leaks, and optimizing fan and pump operations. Implementing the recommendations could save over 200,000 units of electricity annually, reducing energy costs.
Icetech paper the future of marine propulsion - gas hybrid power plantsEdward Eastlack, MSc
This document discusses options for improving marine propulsion systems to reduce emissions and increase efficiency. It describes how hybrid systems combining gas engines with electricity storage can provide benefits like improved transient response and load flexibility for the engines. Various hybridization options are presented, including using batteries, solar panels, wind turbines, and fuel cells to capture alternative energy sources and integrate them into a common DC grid. This allows alternative sources to work with the existing system easily. The document also provides details on gas engine technologies, new electric propulsion systems, and fuel cells as options for marine hybrid power.
This document provides an introduction to fuel systems for tractors and farm machinery. It defines fuel as a substance that produces energy when consumed by an engine. The key components and workings of fuel systems for spark ignition (SI) and compression ignition (diesel) engines are described. For SI engines, the fuel system includes a fuel tank, filter, carburetor and intake manifold. The carburetor mixes air and fuel. For diesel engines, the high-pressure system includes a fuel tank, filter, injection pump and injectors, which supply precisely metered fuel into the combustion chamber. Fuel quality and proper maintenance of filters are discussed as important for optimal system operation.
This document outlines the course objectives and units for an advanced internal combustion engines course. The 5 units cover: 1) spark ignition engines, including air-fuel ratio requirements and carburetor design; 2) compression ignition engines; 3) engine exhaust emission control methods; 4) alternate fuels and their suitability for engines; and 5) recent engine technologies. Key concepts discussed include the stoichiometric air-fuel ratio, factors affecting knock, emission control methods, and properties of various alternate fuels used in engines.
This document discusses various robot drive systems and end effectors. It describes several types of drive systems including hydraulic, pneumatic, and electric drives. Hydraulic drives are suitable for heavy loads but require more maintenance. Pneumatic drives are cheaper but generate more noise and vibration. Electric drives offer cleaner operation but require larger motors. Within electric drives, the document discusses stepper motors, servo motors, and their operating principles. It also covers various types of actuators and their applications in robotics. End effectors such as grippers are also briefly introduced.
This document provides an overview of air conditioning systems, including:
1. It classifies air conditioning systems as either unitary systems (window units, split units, package units) or central systems, and also classifies them based on the season (winter, summer, year-round).
2. Unitary systems are factory assembled while central systems are assembled on-site, and it describes the equipment that makes up each type of system.
3. When selecting a system, factors like customer objectives, economics, occupancy, and thermal load must be considered.
4. Air conditioning systems are also grouped into direct expansion, all-water, all-air, and air-water systems, and it provides
The document discusses vapor compression refrigeration systems (VCRS) and vapor absorption refrigeration systems (VARS) for vehicle air conditioning. VCRS is commonly used but uses environmentally unfriendly refrigerants, while VARS can utilize wasted engine heat and has lower operating costs. VARS works by absorbing refrigerant with a heat source like exhaust gases, while VCRS relies on mechanical compression. VARS offers benefits like reduced noise, lower maintenance needs, and ability to recover otherwise wasted engine heat. The document proposes a VARS design for vehicle air conditioning that recovers exhaust heat as the heat source.
This document discusses methods for assessing compressor performance and optimizing compressed air systems. It provides formulas to calculate a compressor's actual free air delivery (FAD) capacity using the pump-up method. It also describes how to calculate system leakages using the unloading/loading time method and end-use air consumption using either the pump-down or unloading/loading time method depending on receiver size. The document explains that periodic assessment of compressor FAD capacity and air consumption patterns can identify optimization opportunities to reduce energy waste from compressed air systems.
The document describes improvements in plant performance achieved through laser-based combustion optimization at a 660 MW power plant in China. Key results include:
1. Centering the fireball for more uniform heat transfer and reduced slagging through controlling secondary auxiliary air dampers.
2. Balancing oxygen distribution across the furnace to improve combustion by controlling SOFA dampers.
3. Achieving uniform combustion through secondary boundary air damper control based on temperature, oxygen, and carbon monoxide measurements.
4. Automatically reducing excess oxygen levels according to combustion conditions, improving efficiency by reducing flue gas and heat losses. Laser measurements verified more centered fireballs and balanced oxygen distribution with optimization controls in place.
Gas turbines operate using the Brayton cycle, which involves compressing air, adding heat through combustion at constant pressure, expanding the hot gases through a turbine, and rejecting heat at constant pressure. Early gas turbines had low efficiency around 17% but efficiency has increased through higher turbine inlet temperatures, more efficient components, and modifications like regeneration, intercooling, and reheating. Regeneration improves efficiency by heating the compressed air with the turbine exhaust, while intercooling and reheating involve multistage compression and expansion with cooling or heating between stages. Open cycle gas turbines exhaust combustion gases while closed cycle models re-circulate gases, improving efficiency but requiring more complex components.
Review on Boiler Control Automation for Sugar IndustriesIRJET Journal
This document discusses boiler automation systems for sugar industries. It begins with an abstract that outlines controlling boiler parameters like steam generation and drum water level using PID controllers and SCADA systems. It then discusses several key boiler parameters that are controlled like drum level, pressures, temperatures, and flows. Upgrading to advanced automation controls is recommended to improve efficiency by minimizing excess air, allowing tighter emissions control, and improving combustion characterization. Automating the control of critical parameters can help ensure efficient and reliable plant operation.
This is a training module developed in the European project SESEC. More information and the full training can be found here: http://www.sesec-training.eu ...
The document discusses the basics of fuel injection systems in compression ignition (CI) engines. It outlines the key objectives of a fuel injection system which are to meter the correct amount of fuel demanded based on engine load and speed, distribute fuel equally among cylinders, inject fuel at the proper timing and rate, and ensure proper atomization. It also provides details on the typical injection timing window and angle. To achieve these objectives, the key functional components are identified as the pumping element to transport fuel, a metering element to control the fuel supply, a metering control to adjust the metering based on load/speed, and a distribution element to divide fuel evenly among cylinders. Finally, it lists some common types of fuel injection systems used in
An experimental investigation of engine coolant temperature on exhaust emissi...IAEME Publication
This document presents an experimental study on the effect of engine coolant temperature on exhaust emissions of a 3-cylinder, 4-stroke spark ignition engine. The study found that raising the coolant temperature in the engine block reduced hydrocarbon emissions, while lowering the coolant temperature in the cylinder head reduced nitrogen oxide emissions. Testing over coolant temperatures of 45-85°C and engine speeds of 1500-2400 rpm showed decreasing trends in hydrocarbon and nitrogen oxide emissions at higher coolant temperatures and engine loads. The results indicate that exhaust emissions are dependent on engine coolant temperature, with optimal temperatures existing for reducing different pollutants.
This document discusses fuel supply systems and air-fuel ratio requirements for spark ignition engines. It begins by describing the stages of the fuel supply system, including filtration, atomization and the need to finely disperse fuel before combustion. It then discusses the various fuel injection systems used in SI engines, including single-point/throttle body injection where fuel is injected into the throttle body, multi-point/port injection where each cylinder has a dedicated injector, and direct injection where fuel is injected directly into the combustion chamber. The document focuses on the air-fuel ratio requirements for SI engines under different operating conditions such as idling, cruising and high power, and explains why richer or leaner mixtures are needed depending on the situation.
This document provides an overview of fuel systems, including the main components and how they work. It compares carbureted and fuel injected systems, describing the different types of fuel injection. Electronic fuel injection uses sensors, actuators, and a computer to precisely meter fuel delivery. The computer receives feedback from oxygen sensors to continuously adjust the air-fuel ratio for optimal performance and emissions.
This document discusses the history of emissions control for engines, including the discovery of air pollution in Los Angeles in the 1940s. It then covers the introduction of HC and CO emission limits in 1966 which reduced emissions by 95% by the 1980s through more efficient engines and exhaust aftertreatment. The document also discusses the three methods used for emissions control: engineering combustion, optimizing operating parameters, and using aftertreatment devices like catalytic converters. It provides details on the anatomy and functioning of catalytic converters.
The document discusses various aspects of fuel injection systems, including:
1) It describes the basic components and operation of port fuel injection and throttle body injection systems, including the fuel pump, fuel pressure regulator, injectors, and how they are controlled by the computer.
2) It explains the different types of fuel injection systems and how they determine the proper fuel amount, such as speed density and mass air flow systems.
3) It provides diagrams and descriptions of the main components like the fuel rail, injectors, and pressure regulator and how they function within the fuel injection system.
The document discusses the fuel oil system on a locomotive engine. It describes the fuel feed system and fuel injection system.
The fuel feed system supplies fuel oil from the tank to the injection system at high pressure. It includes a primary filter, fuel pump, secondary filter, and fuel header piping. The fuel injection system atomizes and injects the fuel into the cylinders. It consists of high-pressure fuel injectors and fuel injection pumps that deliver fuel at precise timings and quantities. Proper functioning and testing of these systems is important for complete combustion and engine performance.
Review of theModern developments in Suction processes of IC EnginesIJERA Editor
This review paper deals with the evolution of the general processes employed in the suction process of IC
Engines. The suction process has evolved from the traditional use of carburettors to much more sophisticated
systems like CRDi, MPFi, etc. used in modern days. In doing so, various parameters such as the volumetric
efficiency and the turbulence, etc. inside the engine have to be considered. Additional processes such as
supercharging and turbocharging are employed to improve these parameters. It is also highly desirable to vary
the Air-Fuel ratio effectively according to the speed of the engine for better power output and mileage. Thus
researchers have developed several ways over the years to achieve it. Recent research work being carried out in
this field is in the areas of Pressure Wave Superchargers, Variable Geometry Turbochargers, Multiple Intake
valves, Shrouded Intake Valves, Camless Engines etc. Many of these technologies have been employed in the
industry such as the DTS-Si, TDi&i-vtec Engines. Thus, the Automobile Industry has come a long way in
evolving the intake processes and further developments will always be on the way.
This document summarizes the findings of an energy audit conducted at a textile mill in Tirupur, India. It identifies areas of high energy consumption and provides recommendations for improving energy efficiency. The major energy consuming systems identified are humidification plants, air compressors, and the motors used in carding, simplex, spinning, and auto coner departments. Recommendations include replacing old motors with high efficiency models, improving maintenance of humidification and air distribution systems to reduce leaks, and optimizing fan and pump operations. Implementing the recommendations could save over 200,000 units of electricity annually, reducing energy costs.
Icetech paper the future of marine propulsion - gas hybrid power plantsEdward Eastlack, MSc
This document discusses options for improving marine propulsion systems to reduce emissions and increase efficiency. It describes how hybrid systems combining gas engines with electricity storage can provide benefits like improved transient response and load flexibility for the engines. Various hybridization options are presented, including using batteries, solar panels, wind turbines, and fuel cells to capture alternative energy sources and integrate them into a common DC grid. This allows alternative sources to work with the existing system easily. The document also provides details on gas engine technologies, new electric propulsion systems, and fuel cells as options for marine hybrid power.
This document provides an introduction to fuel systems for tractors and farm machinery. It defines fuel as a substance that produces energy when consumed by an engine. The key components and workings of fuel systems for spark ignition (SI) and compression ignition (diesel) engines are described. For SI engines, the fuel system includes a fuel tank, filter, carburetor and intake manifold. The carburetor mixes air and fuel. For diesel engines, the high-pressure system includes a fuel tank, filter, injection pump and injectors, which supply precisely metered fuel into the combustion chamber. Fuel quality and proper maintenance of filters are discussed as important for optimal system operation.
This document outlines the course objectives and units for an advanced internal combustion engines course. The 5 units cover: 1) spark ignition engines, including air-fuel ratio requirements and carburetor design; 2) compression ignition engines; 3) engine exhaust emission control methods; 4) alternate fuels and their suitability for engines; and 5) recent engine technologies. Key concepts discussed include the stoichiometric air-fuel ratio, factors affecting knock, emission control methods, and properties of various alternate fuels used in engines.
This document discusses various robot drive systems and end effectors. It describes several types of drive systems including hydraulic, pneumatic, and electric drives. Hydraulic drives are suitable for heavy loads but require more maintenance. Pneumatic drives are cheaper but generate more noise and vibration. Electric drives offer cleaner operation but require larger motors. Within electric drives, the document discusses stepper motors, servo motors, and their operating principles. It also covers various types of actuators and their applications in robotics. End effectors such as grippers are also briefly introduced.
This document provides an overview of air conditioning systems, including:
1. It classifies air conditioning systems as either unitary systems (window units, split units, package units) or central systems, and also classifies them based on the season (winter, summer, year-round).
2. Unitary systems are factory assembled while central systems are assembled on-site, and it describes the equipment that makes up each type of system.
3. When selecting a system, factors like customer objectives, economics, occupancy, and thermal load must be considered.
4. Air conditioning systems are also grouped into direct expansion, all-water, all-air, and air-water systems, and it provides
The document discusses vapor compression refrigeration systems (VCRS) and vapor absorption refrigeration systems (VARS) for vehicle air conditioning. VCRS is commonly used but uses environmentally unfriendly refrigerants, while VARS can utilize wasted engine heat and has lower operating costs. VARS works by absorbing refrigerant with a heat source like exhaust gases, while VCRS relies on mechanical compression. VARS offers benefits like reduced noise, lower maintenance needs, and ability to recover otherwise wasted engine heat. The document proposes a VARS design for vehicle air conditioning that recovers exhaust heat as the heat source.
This document discusses methods for assessing compressor performance and optimizing compressed air systems. It provides formulas to calculate a compressor's actual free air delivery (FAD) capacity using the pump-up method. It also describes how to calculate system leakages using the unloading/loading time method and end-use air consumption using either the pump-down or unloading/loading time method depending on receiver size. The document explains that periodic assessment of compressor FAD capacity and air consumption patterns can identify optimization opportunities to reduce energy waste from compressed air systems.
The document describes improvements in plant performance achieved through laser-based combustion optimization at a 660 MW power plant in China. Key results include:
1. Centering the fireball for more uniform heat transfer and reduced slagging through controlling secondary auxiliary air dampers.
2. Balancing oxygen distribution across the furnace to improve combustion by controlling SOFA dampers.
3. Achieving uniform combustion through secondary boundary air damper control based on temperature, oxygen, and carbon monoxide measurements.
4. Automatically reducing excess oxygen levels according to combustion conditions, improving efficiency by reducing flue gas and heat losses. Laser measurements verified more centered fireballs and balanced oxygen distribution with optimization controls in place.
Gas turbines operate using the Brayton cycle, which involves compressing air, adding heat through combustion at constant pressure, expanding the hot gases through a turbine, and rejecting heat at constant pressure. Early gas turbines had low efficiency around 17% but efficiency has increased through higher turbine inlet temperatures, more efficient components, and modifications like regeneration, intercooling, and reheating. Regeneration improves efficiency by heating the compressed air with the turbine exhaust, while intercooling and reheating involve multistage compression and expansion with cooling or heating between stages. Open cycle gas turbines exhaust combustion gases while closed cycle models re-circulate gases, improving efficiency but requiring more complex components.
An air pre-heater is a general term to describe any device designed to heat air before another
process (for example, combustion in a boiler) with the primary objective of increasing the thermal efficiency of
the process of the flue gas in a regenerative pre-heater. This project analysis how operation parameters of a
regenerative air preheater can be optimized in order to increase its efficiency and consequently the overall
efficiency of a boiler. As mention in phase-1 project the case study of RAPH is implemented in this work for the
reduction in air leakage by 30% and in order to improve the efficiency of RAPH-2 in Unit-I, TPS-I (Expansion)
of the Regenerative Air Pre-Heater was improved by reducing the leakage of air into flue gas in the RAPH, and
i t is minimized by replacing the ordinary radial seals into “Flexible Seals” and also by proper maintenance of
the RAPH and it is implemented for the experimental analysis. For this purpose, the RAPH in thermal power
station -1 expansion at neyveli is considered and studied for a period and suitable remedies have been
suggested.
1) The Brayton cycle models the ideal thermodynamic cycle of a gas turbine engine. It consists of four processes: isentropic compression, constant-pressure heat addition, isentropic expansion, and constant-pressure heat rejection.
2) The thermal efficiency of an ideal Brayton cycle depends on the pressure ratio and specific heat ratio of the working fluid. Efficiency increases with higher pressure ratios.
3) Actual gas turbine cycles incorporate modifications like regeneration, which uses a heat exchanger to capture heat from the exhaust and transfer it to the compressed air, improving efficiency. Intercooling and reheating can also improve efficiency when used with regeneration.
The document discusses using Zero Stage technology to improve the efficiency and reduce emissions of existing legacy gas turbines used to power compressor stations along pipelines. It works by adding an external compression stage before the gas turbine to optimize combustion conditions and allow the turbine to operate continuously at its most efficient design point, resulting in reduced emissions and increased power output. This can extend the life of older turbines and increase pipeline capacity at a much lower cost than replacement while achieving over 50% reductions in emissions.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Compressed air Energy saving possibilities in textile millsAshok Sethuraman
The textile mills are aware now that in their total Electricity units consumed per day towards compressed air, they are losing more than 30 % units in compressed air. But, in the total Electricity units per day consumption, the mill can achieve only around 5 to 10 % reduction in that Units Per Day after the energy audit & implementation.
But here in compressed air, they find the Low Hanging Fruit with zero & low cost payback. Compressed air leakage is a hidden losses daily happening in the mill and if not identified and corrected today, this aggravates the losses, which are accelerating now.
When the mill goes for modernization, the automated production demands more compressed air usage. So instead of arresting the existing air leakages, now the mill buys more compressors so satisfy the production demands, but leakage increases more.
Improved efficiency of gas turbine by Razin Sazzad MollaRazin Sazzad Molla
This document discusses ways to improve the efficiency of gas turbine engines through various design modifications and upgrades. It describes how increasing turbine inlet temperatures, improving compressor and turbine components, adding modifications like intercooling and regeneration, and utilizing advanced cooling techniques can boost efficiency. Other methods covered include inlet air cooling systems, compressor and turbine coatings, supercharging, and comprehensive component replacements. The goal of ongoing research is to enhance power output while reducing emissions and fuel consumption.
IRJET- Improve the Efficiency of Combined Cycle Power PlantIRJET Journal
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1. Hydrocarbon Processing | MARCH 2015 1
Petrochemicals
V. K. ARORA, Kinetics Process Improvements Inc.,
Houston, Texas
Use multistage integrated chilling
to increase ammonia production
Ammonia plant operators strive to maximize energy ef-
ficiency and ammonia production while minimizing capital
cost and downtime, without adding risk or sacrificing oper-
ating reliability. However, any significant improvement in
energy efficiency without a reasonable increase in ammonia
production rarely meets the payout criteria to justify such re-
vamps, which typically require expensive upgrades and down-
time to debottleneck compressors and other equipment.
A majority of older ammonia plants have been revamped
for higher capacity and improved energy efficiency. Most of
them are still relatively inefficient and have been stretched to
the maximum operating limits of their equipment, including
major compressors, reforming units and steam systems, there-
fore compromising the operating reliability, risks and ratings.
Increasing ammonia plant capacity with MIC. A new
revamp approach uses multistage integrated chilling (MIC).
Along with several other proven measures, the MIC scheme
provides an option that avoids expensive compressor upgrades
for incremental improvements in ammonia production, with
energy efficiency improvements up to 15%, depending on
the plant and on site-specific constraints. For these types of
revamps, the sensitivity analysis demonstrates an economic
attractiveness when gas pricing is above $4/MMBtu and am-
monia pricing is above $400/metric ton.
The MIC process modification is simply a staged thermal
coupling of the ammonia compression system with the pro-
cess air compressor. This technology can potentially increase
the mass throughput of the process air compressor by up to
20% without any compressor or driver modifications, and
with practically little or no impact on its compression power
or driver steam rate. It also does not require an external refrig-
eration system.
A comprehensive study was carried out for a large ammo-
nia plant with all three major compressors operating at their
maximum speed and the reformer induced draft/forced draft
(ID/FD) fans operating at their design limits. With the use of
an MIC scheme, along with other proven measures, no chang-
es in the major compressors or ID/FD fans are needed for
incremental ammonia production of 12% with an improved
energy efficiency of 3 MMBtu/t.
The results of the case study are presented within an over-
all economics picture, along with changes in key operating pa-
rameters and major hardware.
Understanding the MIC process air compressor. Chill-
ing the suction stream prior to entering the compressor sys-
tems has long been practiced in various applications to im-
prove compressor performance. A few ammonia plants have
implemented suction chilling in the process air compressors,
but this provides only a modest increase in air throughput and
is typically supplemented with an additional-standalone pack-
age refrigeration system.
The process air compressor for a mid- to large-sized, older
ammonia plant is usually a multistage centrifugal machine
driven by a steam turbine. It is configured in two casings with
four stages of compression, with each stage separated by an
intercooler, as shown in FIG. 1. The low-pressure (LP) com-
pressor is driven by a condensing turbine using superheated
medium-pressure (MP) steam, and the high-pressure (HP)
compressor is driven through a speed-increasing gear coupled
to the LP machine.
Options for upgrading the process air compressor. To
upgrade the existing process air compressor system, ammonia
plant operators have conventionally used a combination of the
following options:
1. Modifications to the existing compressor internals
and driver
2. A new compressor and new driver
3. Suction chilling, using an external mechanical
refrigeration system
4. Multistage integrated chilling.
Options 1 and 2 require significant downtime and capital
and have long delivery schedules. They also require refurbish-
ment of the driver to meet the added power requirement. Op-
tion 2, with a supplemental air compressor, requires extra space.
Steam
turbine
Gear
Inlet Inst. air
Discharge
Stg. 2 Stg. 1 Stg. 3 Stg. 4
LP
compressor
HP
compressor
FIG. 1. Diagram of a process air compressor for an older ammonia
plant, configured in two casings with four compression stages.
2. 2 MARCH 2015 | HydrocarbonProcessing.com
Petrochemicals
In both of these options, the greater steam demand for the tur-
bine drivers will require an additional surface condenser in the
steam system to accommodate the extra steam condensing load,
unless an electric option is viable. Both of these options have
been implemented in a number of ammonia plants and are eco-
nomically justified, with significant capacity additions that are
typically in excess of 25%.
Option 3, suction chilling, is widely practiced for gas tur-
bines in the power industry, but it is not a very popular option in
ammonia plants. A few ammonia plants have implemented this
option, using an external refrigeration system that adds power
and plot space requirements. This option is much less expensive
than the first two options, but it provides only a modest increase
in air capacity (approximately 5%) and is rarely economically
justified.Thisisevidentfromthefactthatonlyahandfulofcom-
panies have implemented suction chilling in ammonia plants.
Option 4, a new approach using the MIC scheme, provides
a cost-effective option to increase the air capacity by up to 20%
without additional power or the use of an external refrigeration
system. However, this option does require additional space.
The MIC solution. ThetypicalMICschemeshowninFIG. 2 and
FIG. 3 is a staged thermal coupling of the process air compressor
withtheammoniacompressorsystemwithintheammoniaplant.
A direct or indirect chilling scheme, or a combination of the two
schemes, can be used, depending on the site constraints. The di-
rect chilling scheme provides the advantage of being the most ef-
ficient, with the lowest capital and plot space requirements.
As a part of the ammonia plant revamp for higher capacity, the
synthesis loop (synloop) is upgraded with an additional convert-
er bed to suitably increase the single-pass ammonia conversion
rate. Higher ammonia conversion results in a reduced gas circula-
tion flowrate and lower refrigeration demand within the synloop.
The freed-up ammonia streams, which are at different tem-
perature levels from the existing ammonia compressor system,
are suitably integrated in the staged chilling of the process air
compressor, as well as in the makeup syngas compressor. The
extent of thermal integration is suitably staged so as to minimize
the ammonia compression power to well below its maximum
design limits. Furthermore, the extent of the synloop upgrade is
suitably synchronized with the upgrade of the front end of the
ammonia plant to minimize the additional hardware, downtime
and capital requirements.
The higher mass flow of air available is then preheated to
higher than the base temperature, using a combination of split
flow and an external steam exchanger, as shown in FIG. 4. The
use of a split flow scheme is plant- and site-specific, and it great-
ly helps minimize the pressure drop and compression duty with
an additional degree of air preheat to maximize the incremental
ammonia production.
Benefits of MIC scheme with other measures. The MIC
modification, along with other measures, provides the poten-
tial to achieve incremental increases in ammonia capacity and
energy-efficiency improvements up to 15%, with the following
key benefits:
• No modifications are needed for any of the following
major compressors, with only a small change in
additional steam consumption:
o Process air compressors
o Syngas compressor
o Ammonia compressor
• No potential change in the pressure of the main surface
condenser for steam turbines
To stage 2 air
compressor
Condensate
Intake air
via filter
Return headers
Existing ammonia
refrigeration system
Liquid ammonia
To MP surge drum To LP surge drum
Stage 1 air
compressor
FIG. 2. Typical direct MIC scheme.
To stage 2 air
compressor
Condensate
Intake air
via filter
Return headers
Existing ammonia
refrigeration system
Supply headers
To MP surge drum
Liquid NH3
To LP surge drum
Stage 1 air
compressorChilling
water
loop
with
pumps
and
buffer
FIG. 3. Typical indirect MIC scheme.
Air from process air
compressor Primary effluent
Secondary
reformer
Convection
services
Flue gas
FIG. 4. Scheme showing a combination of split flow and an external
steam exchanger.
3. Hydrocarbon Processing | MARCH 2015 3
Petrochemicals
• Proportionately reduced steam demand at all levels
improves energy efficiency
• Reconfiguration and integration allows the temperature
to be increased for the following streams, despite space
constraints in the convection section:
o Process air
o Mixed feed
o Superheated steam
• Increases in the process air flow and temperature allow
the outlet temperature of the secondary reforming
unit to be raised, resulting in reduced methane slip and
improved H2/N2 ratio for better synloop efficiency
• The combination of a higher degree of preheat of mixed
feed coupled with process air easily permits shifting
the reforming load from the primary reformer to the
secondary reformer
• The steam-to-carbon (S:C) ratio in the primary reformer
can also be decreased, despite a reduction in the overall
methane slip, resulting in:
o Reduced arch firing, which could be indirectly used
to raise reformer tube outlet temperature for the same
tube metal temperature
o Reduced load on ID/FD fans, which could be further
reduced by replacing a leak-prone rotary air preheater
o Reduced mass flowrate of syngas to the cooling train,
for improved hydraulics and pressure profile for
higher capacity
• Higher steam superheat temperature coupled with
lower condensing pressure helps to reduce the steam
rates for the same power demand.
Key bottlenecks in old ammonia plants. A majority of the
old ammonia plants are still relatively inefficient, and most of
them are operated close to the design limits of the major equip-
ment. Some of the key bottlenecks in the old ammonia plants
are listed below:
• Limits of ID/FD fans in the primary reformer:
o Excessive air leakage from the old rotary-type
air preheaters
o Higher-than-design excess air for burners
o Proportionately high firing load on arch burners due
to limiting mixed feed preheat temperature, limiting air
preheat temperature and higher-than-design S:C ratio
• Higherinertsinmakeupgas
(MUG):
o Higher-than-expected methane
slip in reforming due to lower
temperature at the outlet of the
secondary reformer, as a result of
limited process air compressor
capacity and limited preheat
temperature of process air
o Higher-than-expected CO2 slip
due to:
❒ Limited solvent circulation
rate
❒ Limited cooling of lean solvent
due to limited cooling water
(CW) or heat transfer surface
❒ Higher-than-expected loading of the lean solvent
❒ Non-optimal solvent concentration
❒ Mass transfer and hydraulic limitations of absorber
and stripper internals
• Major compressors:
o Reached maximum volumetric limit at maximum
design speed
o Actual operational efficiency is lower than design
o Higher-than-design suction temperature (percent
of relative humidity for air compressors)
o Limited intercooling
o Unfavorable plant hydraulics (lower-than-design
suction pressure)
• Plant throughput limitations:
o Higher-than-design S:C ratio
o Higher-than-design level of inerts in MUG
o Inefficient synloop and poor feed efficiency
o Higher-than-expected system pressure drop
• Excessive steam venting from the deaerator:
o Excessive reboil load in CO2 strippers
o Excessive temperature in the main surface condenser
• Higher temperature in the main surface condenser
of turbines:
o Excessive backpressure due to higher-than-design load
o Limiting heat transfer surface
o Efficiency loss in condensing turbines due to lower
steam superheat temperature and higher-than-expected
steam rates.
Case study. A case study of a large ammonia plant is outlined.
The referenced ammonia plant had been stretched to its operat-
ing limits, with the following constraints:
• Process air compressor near its maximum design speed
• ID/FD fans of the primary reformer at full open conditions
• Syngas compressor near its maximum design speed
• Ammonia compressor near its maximum design speed
• No extra space in the convection section to add coils
• High inerts in MUG due to high methane and CO2 slippage
• Excess venting of steam from the deaerator
• High energy consumption.
This revamp study posed a major challenge to provide viable
capacity and energy improvements without expensive compres-
sor upgrades.
Base speed:
103.6%
Overall performance curve-base
(process air compressor) ammonia capacity: 100%
Overall performance curve-with MIC
(process air compressor) ammonia capacity: 112%
Volumetric flow, %
Mass flow, %
Volumetric flow, %
Mass flow, %
Speed with MIC:
101.4%
105%105%
100%
Dischargepressure,%
Dischargepressure,%
100%
100% 114%
108
100
FIG. 5. The mass flowrate of the process air compressor is increased, with reduced speed and
without any increase in its power requirement.
4. 4 MARCH 2015 | HydrocarbonProcessing.com
Petrochemicals
List of major modifications. Based on a comprehensive
study using the MIC scheme, no upgrades were required in
any of the major compressors for a capacity increase of 12%,
along with energy savings of 3 MMBtu/t. The following major
changes were required as a part of the revamp:
• MIC system
• Replacement of rotary air preheater with plate-type
preheater
• Minor modifications of feed preheat coil
• LP flash column system in CO2 removal
• Additional single-bed converter
• Few parallel exchangers for
additional duty
• Larger impellers for pumps.
Key performance parameters for the
base case and the MIC revamp are shown
in TABLE 1.
Process air compressor. Using the
MIC scheme, including the two inter-
mediate stages, the mass flowrate of the
process air compressor is increased to
114% with reduced speed and without
any increase in its power requirement, as
indicated in FIG. 5.
All of the chilling duty is internally supplied, without any
need for an external refrigeration package. No modifications of
the air compressor or its driver are required. Each stage of the air
compressor is rated for its limitations and any cooling require-
ment for the target capacity. The MIC scheme is suitably staged
and optimized to minimize the compression requirements of
both ammonia and air compressors, along with some additional
modifications for size, space and capital requirements.
The speed of the makeup syngas compressor is also reduced
for the revamp case. It is accomplished by slightly raising its
suction pressure and by lowering the suction temperature.
With a balanced upgrade of the synloop and the front end,
the speed of the ammonia compressor is marginally reduced.
Reforming area. Reconfiguration and integration allow the
temperature of the following streams in the reforming area to be
increased, despite space constraints in the convection section:
• Process air
• Mixed feed
• Superheated steam.
Increases in the process air flow and temperature permit a
rise in the outlet temperature of the secondary reforming, re-
sulting in reduced methane slip and an improved H2/N2 ratio
for better synloop efficiency.
A combination of a higher degree of preheat of mixed feed
coupled with higher temperature of the process air easily permits
shifting of the reforming load from the primary reformer to the
secondary reformer. In addition, the S:C ratio in the primary re-
former is also reduced, despite a decrease in the overall methane
slip that results in reduced arch firing, which could be indirectly
used to raise the reformer tube outlet temperature without affect-
ing the tube metal temperature. It also helps reduce the load on
theID/FDfans,whichcouldbeevenfurtherimprovedbyreplac-
ingtheleak-pronerotaryairpreheaterwithaplate-typepreheater.
A reduced mass flowrate of syngas (due to a lower S:C ratio)
to the cooling train also helps the hydraulics and the pressure
profile for higher capacity. A higher steam superheat tempera-
ture coupled with lower condensing pressure helps reduce the
steam rates for the same power demand.
CO2-removal area. The CO2-removal system scheme is a
conventional, single-stage MDEA and piperazine.
To overcome the mass-transfer and hydraulics limitations
in the CO2-removal sections, several schemes were simulated
800
-8
-6
-4
-2
0
2
4
6
825
Superheat temperature, °F
MP steam temperature vs. steam rate
Steamratechange,%
850 900
FIG. 7. MP steam temperature vs. steam rate.
TABLE 1. Key performance parameters
Parameter Base case Revamp
Ammonia capacity Base 112%
Energy consumption, MMBtu/t Base –3
Mixed feed preheat temp., °F Base +40
S:C ratio, mol % 3.5 3.15
Process air preheat temp., °F Base 105
Steam superheat temp., °F Base +35
Secondary outlet temp., °F Base +50
MUG suction pressure, psi Base +15
Inerts in MUG, mol% Base 65%
MUG H2/N2 ratio, mol% 3.06 3
Loop H2/N2 ratio, mol % 3.65 3
NH3 in converter effluent Base +5% mol
Purge rate, mass rate Base 88%
Ammonia concentration profile, two beds (base)
Ammonia capacity: 100%
Ammonia concentration profile, three beds (revamp)
Ammonia capacity: 112%
Temperature Temperature
Dischargeconcentration,mol%
25
Dischargeconcentration,mol%
25
00
FIG. 6. The ammonia loop is upgraded with an additional single-bed converter.
5. Hydrocarbon Processing | MARCH 2015 5
Petrochemicals
and further reviewed based on a cost-benefit analysis. Several
changes were made in the revamp scheme:
1. Optimization of the MDEA and piperazine
concentration in the solvent
2. Inclusion of an LP flash tower to offload the stripper
reboiler duties by 16%
3. Replacement of existing packing with more efficient,
lower-pressure drop packing
4. Replacement of the pump impellers, along with the
supplemental exchanger area
5. Addition of the hydraulic turbine in the rich solvent stream.
A two-stage scheme was also considered and simulated, but
was discontinued based on the cost-benefit analysis.
The cooler lean solvent, coupled with a slight increase in
lean solvent flow, helped to significantly reduce the CO2 slip,
thereby lowering the total inerts to the loop.
Reducing the CO2 stripper duty by approximately 16%
offloaded the stripper internals without any modification re-
quired, and completely eliminated the large continuous steam
vent from the deaerator, resulting in energy savings.
Ammonia synloop. The ammonia loop is suitably upgraded
with an additional single-bed converter, as shown in FIG. 6, with
a relative ammonia concentration profile. The upgraded am-
monia conversion is carefully chosen to balance the capacity
increase in the front end for minimum modifications and capi-
tal requirements.
800
-8
-6
-4
-2
0
2
4
6
825
Superheat temperature, °F
HP steam temperature vs. steam rate
Steamratechange,%
850 900
FIG. 8. HP steam temperature vs. steam rate.
3.5 4.5 5.5 6.5 7.5 8.5 9.5
-8 100
110
120
130
140
150
160
170
-6
-4
-2
0
2
4
6
8
Surface condenser pressure, in. Hg
Surface condenser
Condensing pressure vs. steam rate
Steamratechange,%
Surfacecondensingtemperature,°F
FIG. 9. Condensing pressure vs. steam rate.
Contact
VK ARORA
(01) 2817731629
vka@kpieng.com
6. 6 MARCH 2015 | HydrocarbonProcessing.com
Petrochemicals
With an increase of ammonia conversion in the synloop,
the refrigeration duty requirement from the ammonia com-
pressor is significantly reduced. The spare load from the am-
monia compressor is used to provide the chilling duty of the
process air compressor and the makeup syngas compressor
without any modifications or power increases in the ammonia
compressor.
With a higher ammonia conversion, the outlet tempera-
ture will increase beyond the design temperature of the exist-
ing boiler feedwater (BFW) preheater. For this reason, a new
exchanger is added before the existing BFW preheater. In ad-
dition, a parallel CW exchanger is added for more ammonia
condensation at the CW level.
Steam system. The steam system is suitably optimized and
balanced for higher ammonia capacity. It takes advantage of a
higher degree of steam superheat at the HP and MP levels, and
it also reduces the steam rates to minimize the surface con-
denser pressure and load.
Furthermore, by reducing the stripper reboil duty, the LP
vent from the deaerator or excess LP steam can be significant-
ly minimized, resulting in improved energy efficiency.
For every 50°F temperature rise in the degree of superheat,
the condensing steam turbine steam demand will decrease by
about 3.5%, as shown in FIG. 7 and FIG. 8.
Most of the surface condensers in ammonia plants are over-
loaded with as high as 9 in. of mercury (Hg) pressure, as op-
posed to a typical Hg pressure of 3.5 in. to 4.5 in. for normal
operation. For a reduction of every 1 in. of Hg in backpressure
in the main surface condenser, there is an approximate rise in
condensing turbine efficiency of about 3%, as indicated in FIG. 9.
Economics. The economics of the case
study, in terms of internal rate of return
(IRR) for ammonia pricing of $400/met-
ric ton and $500/metric ton, are shown
in FIG. 10 and FIG. 11. IRR estimation also
considers varying gas prices of $4/MM-
Btu to $10/MMBtu in step changes of
$2/MMBtu, along with the capital sen-
sitivity from –10% to +20%. This estima-
tion provides a reasonable representation
of various global locations for the assess-
ment of the MIC scheme.
The following assumptions are used in
the economic evaluation:
• CAPEX: total installed cost,
including owner’s costs
• Project completion: 36 months
• Operating rate: 100%
• Utility rates: typical of US
Gulf Coast
• Financing: internally funded
(no debt)
• Lifecycle: 15 years
• Discount rate: 10%
• Loan interest: 8%
• Tax rate: 25%
• New catalyst life: 15 years
• Ammonia prices: $400/metric ton
and $500/metric ton.
As expected, the IRR greatly improves with higher ammo-
nia and gas prices. Interestingly, the estimated IRR is higher
than the typical minimum of 15%, even with the lowest gas
price of $4/MMBtu and a 20% higher CAPEX than estimated.
The IRR improves with higher ammonia and gas prices.
Takeaway. The MIC scheme, in conjunction with other pro-
cess improvement measures, provides a cost-effective option
to ammonia plant operators for incremental improvements in
capacity and energy efficiency up to 15%, while avoiding ex-
pensive upgrades of major compressors.
The sensitivity analysis demonstrates an economic attrac-
tiveness for gas prices above $4/MMBtu and ammonia prices
above $400/metric ton, mainly for revamps. The ammonia
plant locations with higher feed gas prices will provide higher
economic returns.
The opportunity to use these incremental improvements in
ammonia plants is most promising in situations where capital
and/or additional feed gas availability is limited.
10
0
5
10
15
20
25
30
35
40
50
60
70
Base 10
Base investment, %
$4/MMBtu gas
$6/MMBtu gas
$8/MMBtu gas
$10/MMBtu gas
IRR,%
15 20
FIG. 10. IRR for ammonia pricing of $400/metric ton.
10
0
5
10
15
20
25
30
35
40
50
60
70
Base 10
Base investment, %
$4/MMBtu gas
$6/MMBtu gas
$8/MMBtu gas
$10/MMBtu gas
IRR,%
15 20
FIG. 11. IRR for ammonia pricing of $500/metric ton.
V. K. ARORA is the director of process and strategic business
development at Kinetics Process Improvements (KPI Inc.)
in Houston. Prior to this role, he was responsible for the
development and implementation of a large petrochemicals
complex for a Saudi Arabia location to produce acrylic acid,
oxo-alcohols, syngas and esters. He is presently involved in the
development of a new ammonia project from offgases. He is a
licensed professional engineer in Texas with a BTech degree in chemical
engineering from IIT, in Delhi, India. Prior to joining KPI, he worked at CBI/Lummus
in the US in various positions, including technology director and manager. He also
worked at KBR, SABIC, B&V, Reliance, and Technip in various process functions,
including design and startup.