The document provides information on different types of boilers. It discusses fire tube boilers, water tube boilers, packaged boilers, stoker fired boilers, pulverized fuel boilers, waste heat boilers, and fluidized bed boilers. It describes the basic design and functioning of these different boiler types. It also discusses components of boiler systems, common fuels used in boilers, and details the mechanisms and advantages of fluidized bed combustion systems like atmospheric fluidized bed combustion and circulating fluidized bed combustion.
This document provides information about boilers, including:
1. It defines what constitutes a boiler according to Indian law and defines related terms like boiler components and steam pipes.
2. It describes the basic systems that make up a boiler system, including the water treatment, fuel supply, air supply, and flue gas systems.
3. It lists different types of fuels that can be used in boilers and describes the main types of boilers, including fire tube, water tube, packaged, stoker fired, pulverized fuel, waste heat, and fluidized bed boilers.
Boiler & co generation presentation finished not yetRohit Meena
This document provides information on boilers and co-generation plants. It discusses the major components of such plants including the DM plant, coal handling plant, co-generation plant, ash handling plant, and boiler. It then goes into details about boilers, describing them as enclosed pressure vessels that use combustion to heat water into steam. It discusses the process of evaporation and how steam volume increases. The document also provides information on co-generation plants, fluidized bed combustion boilers, auxiliary equipment for boilers like fans and heat exchangers, and details on pulverized fuel boilers.
The document discusses fluidized bed combustion boilers. It describes the introduction and history of FBC boilers, their mechanism and characteristics, types including atmospheric fluidized bed combustion, circulating fluidized bed combustion, and pressurized fluidized bed combustion. It provides details on the components of FBC boilers like fuel and air distribution systems, heat transfer surfaces, and ash handling. It compares the advantages of FBC boilers to conventional boilers such as higher efficiency, fuel flexibility, lower emissions, and easier ash removal. The only disadvantage mentioned is the higher power requirement for the forced draft fan.
This document contains questions and answers about fluidized bed combustion (FBC) boilers. It includes objective questions with single correct answers on topics like FBC operating parameters, pollutant control methods, and boiler components. It also includes short answer and long form questions about FBC boiler types, combustion mechanisms, heat transfer, retrofitting conventional boilers, and performance of circulating fluidized bed combustion boilers. The document serves as a question bank for energy managers and auditors to assess knowledge of FBC boiler technology.
This document provides an overview of circulating fluidized bed (CFB) boiler design, operation, and maintenance. It begins with introductions to CFB development, typical components, advantages, and hydrodynamic regimes. Key points covered include the bubbling, turbulent, and fast fluidization regimes; effects of circulation rate and particle size on voidage profiles; and the core-annulus model of particle flow. Combustion stages and factors affecting efficiency are then discussed, along with considerations for biomass combustion such as agglomeration risks. The document aims to provide understanding of CFB hydrodynamics, combustion, design basics, and operational/maintenance topics.
1. The document discusses fluidized bed combustion (FBC) technology for energy conversion. FBC allows fuel to be burned and maintained in a fluidized state, improving combustion efficiency.
2. FBC offers advantages like fuel flexibility and lower emissions compared to traditional combustion methods. It can burn a variety of fuels like biomass, waste, and coal.
3. The key mechanisms of FBC involve fluidizing a bed of solid particles like sand with an upward air flow, creating a liquid-like bubbly mixture for thorough fuel combustion at lower temperatures than traditional boilers.
There are several types of boilers that are classified based on how the hot gases and water circulate within the boiler. The main types are fire-tube boilers where hot gases pass through tubes surrounded by water, water-tube boilers where water passes through tubes surrounded by hot gases, packaged boilers which are self-contained, and stoker-fired boilers which use grates to continuously feed coal for burning. Each boiler type has advantages and disadvantages for applications like industrial use, responding to changing loads, and efficiency.
The document provides an overview of Circulating Fluidized Bed Combustion (CFBC) technology. It discusses how CFBC works, including operating at lower temperatures than pulverized coal combustion to reduce emissions while effectively burning a variety of fuels. CFBC has advantages like fuel flexibility, high combustion efficiency, in-situ pollution control, and operational flexibility. Over 310 CFBC boilers are in operation worldwide. Major technology suppliers include Foster Wheeler, Lurgi, Babcock & Wilcox, and the technology is commercially proven.
This document provides information about boilers, including:
1. It defines what constitutes a boiler according to Indian law and defines related terms like boiler components and steam pipes.
2. It describes the basic systems that make up a boiler system, including the water treatment, fuel supply, air supply, and flue gas systems.
3. It lists different types of fuels that can be used in boilers and describes the main types of boilers, including fire tube, water tube, packaged, stoker fired, pulverized fuel, waste heat, and fluidized bed boilers.
Boiler & co generation presentation finished not yetRohit Meena
This document provides information on boilers and co-generation plants. It discusses the major components of such plants including the DM plant, coal handling plant, co-generation plant, ash handling plant, and boiler. It then goes into details about boilers, describing them as enclosed pressure vessels that use combustion to heat water into steam. It discusses the process of evaporation and how steam volume increases. The document also provides information on co-generation plants, fluidized bed combustion boilers, auxiliary equipment for boilers like fans and heat exchangers, and details on pulverized fuel boilers.
The document discusses fluidized bed combustion boilers. It describes the introduction and history of FBC boilers, their mechanism and characteristics, types including atmospheric fluidized bed combustion, circulating fluidized bed combustion, and pressurized fluidized bed combustion. It provides details on the components of FBC boilers like fuel and air distribution systems, heat transfer surfaces, and ash handling. It compares the advantages of FBC boilers to conventional boilers such as higher efficiency, fuel flexibility, lower emissions, and easier ash removal. The only disadvantage mentioned is the higher power requirement for the forced draft fan.
This document contains questions and answers about fluidized bed combustion (FBC) boilers. It includes objective questions with single correct answers on topics like FBC operating parameters, pollutant control methods, and boiler components. It also includes short answer and long form questions about FBC boiler types, combustion mechanisms, heat transfer, retrofitting conventional boilers, and performance of circulating fluidized bed combustion boilers. The document serves as a question bank for energy managers and auditors to assess knowledge of FBC boiler technology.
This document provides an overview of circulating fluidized bed (CFB) boiler design, operation, and maintenance. It begins with introductions to CFB development, typical components, advantages, and hydrodynamic regimes. Key points covered include the bubbling, turbulent, and fast fluidization regimes; effects of circulation rate and particle size on voidage profiles; and the core-annulus model of particle flow. Combustion stages and factors affecting efficiency are then discussed, along with considerations for biomass combustion such as agglomeration risks. The document aims to provide understanding of CFB hydrodynamics, combustion, design basics, and operational/maintenance topics.
1. The document discusses fluidized bed combustion (FBC) technology for energy conversion. FBC allows fuel to be burned and maintained in a fluidized state, improving combustion efficiency.
2. FBC offers advantages like fuel flexibility and lower emissions compared to traditional combustion methods. It can burn a variety of fuels like biomass, waste, and coal.
3. The key mechanisms of FBC involve fluidizing a bed of solid particles like sand with an upward air flow, creating a liquid-like bubbly mixture for thorough fuel combustion at lower temperatures than traditional boilers.
There are several types of boilers that are classified based on how the hot gases and water circulate within the boiler. The main types are fire-tube boilers where hot gases pass through tubes surrounded by water, water-tube boilers where water passes through tubes surrounded by hot gases, packaged boilers which are self-contained, and stoker-fired boilers which use grates to continuously feed coal for burning. Each boiler type has advantages and disadvantages for applications like industrial use, responding to changing loads, and efficiency.
The document provides an overview of Circulating Fluidized Bed Combustion (CFBC) technology. It discusses how CFBC works, including operating at lower temperatures than pulverized coal combustion to reduce emissions while effectively burning a variety of fuels. CFBC has advantages like fuel flexibility, high combustion efficiency, in-situ pollution control, and operational flexibility. Over 310 CFBC boilers are in operation worldwide. Major technology suppliers include Foster Wheeler, Lurgi, Babcock & Wilcox, and the technology is commercially proven.
This document provides an overview of various types of boilers and thermal fluid heaters used in industrial applications. It describes the key components and operating principles of fire tube boilers, water tube boilers, packaged boilers, fluidized bed combustion boilers, stoker fired boilers, pulverized fuel boilers, waste heat boilers, and thermic fluid heaters. Boilers are used to generate steam for industrial processes by transferring heat from fuel combustion to water, while thermal fluid heaters use oil as a heat transfer medium to maintain constant process temperatures. The document compares the advantages of different boiler and heater designs for various steam capacities, pressures, fuels, and temperature requirements.
Thermal Engineering is a specialised sub-discipline of Mechanical Engineering that deals exclusively with heat energy and its transfer between not only different mediums, but also into other usable forms of energy. A Thermal Engineer will be armed with the expertise to design systems and process to convert generated energy from various thermal sources into chemical, mechanical or electrical energy depending on the task at hand. Obviously, all Thermal Engineers are experts in all aspects of heat transfer.
Many process plants (basically somewhere where some raw material or resource is converted into something useful, e.g. power plants, oil refineries, plastic manufacturing plants, etc.) contain countless components and systems which have to be designed in terms of their heat transfer; it is particularly important to ensure that not too much heat is retained so the component or process is not disrupted. Conversely, some processes or systems are designed to use heat to their advantage and a Thermal Engineer must make sure enough heat is generated and used wisely (i.e. sustainably).
This lecture provided an overview of combustion in boilers including general boiler designs, applications of different boiler configurations, types of fuels used and related combustion systems, burner designs, and emission control methods. Key topics covered included heat balances and transfers, excess air calculations, sizing of combustion chambers, gas, liquid, and solid fuel burning systems, and techniques for reducing emissions like NOx, CO2, and particulate matter.
A boiler is a closed vessel that heats water or another fluid. Boilers are constructed from low-carbon steel and have corrugated furnaces for strength. On ships, steam is used for heating, powering turbines, pumps, and other machinery. There are different types of boilers classified by their orientation, circulation method, pressure rating, and whether water or hot gases pass through tubes. Fire tube boilers have hot gases passing through tubes surrounded by water while water tube boilers have water passing through tubes surrounded by hot gases. Packaged boilers are self-contained and efficient units that produce steam quickly.
Circulating fluidizing bed combustion Boiler presentation Sawan Vaja
CFBC boilers operate at high temperatures of 850-900 degrees Celsius and velocities of 4-7 meters per second. They allow for the combustion of low-grade fuels like coal rejects, rice husk, and wood chips. In a CFBC boiler, fuel particles are suspended in a bubbling fluidized bed and burned using a mixture of air injected from below. Ash and partially burned fuel circulate and re-burn, improving efficiency. CFBC boilers have advantages like high fuel flexibility, reduced emissions, and simpler operation compared to traditional boilers.
The document discusses the key benefits and evolution of circulating fluidized bed combustion (CFBC) boiler technology. It provides details on the design and operation of CFBC boilers, including their furnace design, U-beam particle separator system, convection pass, and improved performance from two-stage particle separation. CFBC boilers offer benefits like high combustion efficiency, fuel flexibility, compact design, low emissions, and reduced maintenance costs compared to earlier boiler technologies.
The presentation deals with the most complex and fundamental process in a CFBC boiler. i.e., Combustion. Provides an insight into the various features in a CFBC boilers which are incorporated to enhance cpmbustion.
Circulating Fluidized Bed Boiler (cfb) training module Alexander Ual
This document discusses operating a circulating fluidized bed boiler. It provides information on coal as a fuel source including average sale prices of different coal ranks in 2015. It then discusses hydrodynamics conditions in different locations of a CFB boiler like the furnace and cyclone. Key parameters for CFB hydrodynamics include minimum fluidization velocity and gas holdup. The document compares hydrodynamic regimes like bubbling and fast fluidization. It also provides combustion information like materials used and their properties in a CFB boiler.
Boilers and-its-mountings and Boiler accessoriesRipuranjan Singh
A boiler is defined as "a closed vessel in which water or other liquid is heated, steam or vapor is generated, steam is superheated, or any combination thereof, under pressure or vacuum, for use external to itself, by the direct application of energy from the combustion of fuels, from electricity or nuclear energy."
Boiler accessories are those components which are installed either inside or outside the boiler to increase the efficiency of the plant and to help in the proper working of the plant
Boiler mountings are the machine components that are mounted
over the body of the boiler itself for the safety of the boiler and for
complete control of the process of steam generation.
Various boiler mountings are as under
1) Pressure gauge
2) Water Level Indicator
3) Fusible plug
4)Safety Valve
i) Lever Safety Valve
ii) Spring Loaded safety Valve
5) Steam stop valve
6) Feed check valve
7) Blow off cock
The document discusses traditional pulverized fuel firing systems and circulating fluidized bed combustion (CFBC) boilers. It provides details on the principles and types of CFBC boilers, as well as their advantages over traditional systems, including greater fuel flexibility, lower emissions, and easier desulfurization. CFBC boilers allow for in-furnace reduction of NOx and SOx through low-temperature combustion and the addition of limestone, providing an inherently more environmentally friendly combustion system compared to pulverized fuel firing.
Steam is generated in a boiler by applying heat to water under pressure. Different types of boilers include fire tube boilers, water tube boilers, packaged boilers, stoker fired boilers, pulverized fuel boilers, and waste heat boilers. Boilers can use various solid, liquid, and gaseous fuels as well as agricultural waste. The principle of operation involves fuel combustion generating heat that evaporates water to produce steam, with a steam pipe transporting the steam out and a feedwater pipe replacing evaporated water to maintain pressure. Safety devices like safety valves and burners must also be considered.
Fluidized bed combustor design and features, Fluidized-bed combustion is a process in which solid particles are made to exhibit fluid-like properties by suspending these particles in an upwardly flowing evenly distributed fluid (air or gas) stream.
Combustion takes place in the bed with high heat transfer to the furnace and low combustion temperatures.
The document discusses two options to improve super heaters in AFBC boilers. The first option is designing radiant super heaters that avoid problems with bed super heaters like clinker formation and space constraints. Radiant super heaters have a longer replacement period of 25 years. The second option is coating existing bed super heater tubes with infiltration brazed tungsten carbide cladding, which reduces corrosion and erosion while increasing tube life four times. Both options greatly increase super heater availability.
This document provides an overview of industrial, commercial, and institutional (ICI) boilers. It discusses how boilers work to convert the chemical energy in fuel into thermal energy. ICI boilers come in various sizes and configurations depending on their fuel source and required output. They are generally classified as either firetube or watertube boilers. Firetube boilers have tubes that combustion gases flow through to heat surrounding water, while watertube boilers circulate gases around outside of water-filled tubes. The document describes common types of firetube and watertube boilers and their typical fuel sources.
This document discusses steam generators (boilers) and is divided into three parts. The first part covers introduction and types of steam generators. The second part discusses the parts, accessories, and auxiliaries of steam generators. The third part covers the design, efficiency, performance, and protection of steam generators. It provides details on classification, fundamental design considerations, combustion processes, fuel analysis, boiler efficiency calculation methods, and factors that influence boiler performance such as heat losses.
Boilers have several uses including generating steam to drive turbines for electricity production, and to provide steam for heating, cooling and industrial processes. Boilers can be classified based on their orientation, water and gas flow design, furnace location, circulation method, pressure rating, mobility, and number of tubes. Common boiler types include fire tube boilers like Cochran and Lancashire where gases pass through tubes and water surrounds them, and water tube boilers like Babcock & Wilcox where water passes through tubes and gases surround them. Each boiler type has advantages like efficiency, capacity, and cost, but also limitations regarding pressure, size, and complexity.
The document provides an overview of steam generation and steam generators. It discusses how steam generators convert water into steam through boiling for applications like power generation and industrial heating. Steam generators can range in size from small package boilers producing 1000 lb/h of steam to large utility boilers producing over 10 million lb/h. Key components of steam generation systems include the steam generator, turbines, condensers, pumps, and sometimes nuclear reactors or pollution control devices.
A boiler is a device that generates steam by transferring heat from burning fuel to water. There are two main types: fire-tube boilers where hot gases pass through tubes surrounded by water, and water-tube boilers where water passes through tubes surrounded by hot gases. Boilers have many applications including power generation, heating, and industrial processes. Key factors in boiler selection include required steam properties, size, cost, and fuel/water availability. Boilers are also classified based on design features such as tube layout, firing method, pressure, and circulation.
A boiler is a closed vessel that transfers heat from fuel combustion to water, converting it into steam for power generation, industrial processes, and heating. Boilers are classified based on their heat source, circulation method, orientation, and whether they are stationary or mobile. A boiler is a mechatronics system that uses sensors to monitor heat, water level, and pressure, sending signals to a control unit consisting of a microcontroller and other components that regulate the system without human interference through actuators like water valves.
This document discusses boiler blowdown, which is the process of removing concentrated boiler water and replacing it with fresh feedwater. It provides information on:
- Common impurities in raw water that can cause scaling, sludge, corrosion, or foaming in boilers.
- Guidelines for maximum total dissolved solids levels in boiler water depending on boiler type to avoid issues.
- A formula for calculating the required blowdown rate to maintain a target boiler water total dissolved solids level based on feedwater quality and boiler steam rate.
- An example calculation of the blowdown rate required for a specific boiler operating at 10,000 kg/h steam with 250 ppm feedwater to maintain 2,500
This document provides an overview of various types of boilers and thermal fluid heaters used in industrial applications. It describes the key components and operating principles of fire tube boilers, water tube boilers, packaged boilers, fluidized bed combustion boilers, stoker fired boilers, pulverized fuel boilers, waste heat boilers, and thermic fluid heaters. Boilers are used to generate steam for industrial processes by transferring heat from fuel combustion to water, while thermal fluid heaters use oil as a heat transfer medium to maintain constant process temperatures. The document compares the advantages of different boiler and heater designs for various steam capacities, pressures, fuels, and temperature requirements.
Thermal Engineering is a specialised sub-discipline of Mechanical Engineering that deals exclusively with heat energy and its transfer between not only different mediums, but also into other usable forms of energy. A Thermal Engineer will be armed with the expertise to design systems and process to convert generated energy from various thermal sources into chemical, mechanical or electrical energy depending on the task at hand. Obviously, all Thermal Engineers are experts in all aspects of heat transfer.
Many process plants (basically somewhere where some raw material or resource is converted into something useful, e.g. power plants, oil refineries, plastic manufacturing plants, etc.) contain countless components and systems which have to be designed in terms of their heat transfer; it is particularly important to ensure that not too much heat is retained so the component or process is not disrupted. Conversely, some processes or systems are designed to use heat to their advantage and a Thermal Engineer must make sure enough heat is generated and used wisely (i.e. sustainably).
This lecture provided an overview of combustion in boilers including general boiler designs, applications of different boiler configurations, types of fuels used and related combustion systems, burner designs, and emission control methods. Key topics covered included heat balances and transfers, excess air calculations, sizing of combustion chambers, gas, liquid, and solid fuel burning systems, and techniques for reducing emissions like NOx, CO2, and particulate matter.
A boiler is a closed vessel that heats water or another fluid. Boilers are constructed from low-carbon steel and have corrugated furnaces for strength. On ships, steam is used for heating, powering turbines, pumps, and other machinery. There are different types of boilers classified by their orientation, circulation method, pressure rating, and whether water or hot gases pass through tubes. Fire tube boilers have hot gases passing through tubes surrounded by water while water tube boilers have water passing through tubes surrounded by hot gases. Packaged boilers are self-contained and efficient units that produce steam quickly.
Circulating fluidizing bed combustion Boiler presentation Sawan Vaja
CFBC boilers operate at high temperatures of 850-900 degrees Celsius and velocities of 4-7 meters per second. They allow for the combustion of low-grade fuels like coal rejects, rice husk, and wood chips. In a CFBC boiler, fuel particles are suspended in a bubbling fluidized bed and burned using a mixture of air injected from below. Ash and partially burned fuel circulate and re-burn, improving efficiency. CFBC boilers have advantages like high fuel flexibility, reduced emissions, and simpler operation compared to traditional boilers.
The document discusses the key benefits and evolution of circulating fluidized bed combustion (CFBC) boiler technology. It provides details on the design and operation of CFBC boilers, including their furnace design, U-beam particle separator system, convection pass, and improved performance from two-stage particle separation. CFBC boilers offer benefits like high combustion efficiency, fuel flexibility, compact design, low emissions, and reduced maintenance costs compared to earlier boiler technologies.
The presentation deals with the most complex and fundamental process in a CFBC boiler. i.e., Combustion. Provides an insight into the various features in a CFBC boilers which are incorporated to enhance cpmbustion.
Circulating Fluidized Bed Boiler (cfb) training module Alexander Ual
This document discusses operating a circulating fluidized bed boiler. It provides information on coal as a fuel source including average sale prices of different coal ranks in 2015. It then discusses hydrodynamics conditions in different locations of a CFB boiler like the furnace and cyclone. Key parameters for CFB hydrodynamics include minimum fluidization velocity and gas holdup. The document compares hydrodynamic regimes like bubbling and fast fluidization. It also provides combustion information like materials used and their properties in a CFB boiler.
Boilers and-its-mountings and Boiler accessoriesRipuranjan Singh
A boiler is defined as "a closed vessel in which water or other liquid is heated, steam or vapor is generated, steam is superheated, or any combination thereof, under pressure or vacuum, for use external to itself, by the direct application of energy from the combustion of fuels, from electricity or nuclear energy."
Boiler accessories are those components which are installed either inside or outside the boiler to increase the efficiency of the plant and to help in the proper working of the plant
Boiler mountings are the machine components that are mounted
over the body of the boiler itself for the safety of the boiler and for
complete control of the process of steam generation.
Various boiler mountings are as under
1) Pressure gauge
2) Water Level Indicator
3) Fusible plug
4)Safety Valve
i) Lever Safety Valve
ii) Spring Loaded safety Valve
5) Steam stop valve
6) Feed check valve
7) Blow off cock
The document discusses traditional pulverized fuel firing systems and circulating fluidized bed combustion (CFBC) boilers. It provides details on the principles and types of CFBC boilers, as well as their advantages over traditional systems, including greater fuel flexibility, lower emissions, and easier desulfurization. CFBC boilers allow for in-furnace reduction of NOx and SOx through low-temperature combustion and the addition of limestone, providing an inherently more environmentally friendly combustion system compared to pulverized fuel firing.
Steam is generated in a boiler by applying heat to water under pressure. Different types of boilers include fire tube boilers, water tube boilers, packaged boilers, stoker fired boilers, pulverized fuel boilers, and waste heat boilers. Boilers can use various solid, liquid, and gaseous fuels as well as agricultural waste. The principle of operation involves fuel combustion generating heat that evaporates water to produce steam, with a steam pipe transporting the steam out and a feedwater pipe replacing evaporated water to maintain pressure. Safety devices like safety valves and burners must also be considered.
Fluidized bed combustor design and features, Fluidized-bed combustion is a process in which solid particles are made to exhibit fluid-like properties by suspending these particles in an upwardly flowing evenly distributed fluid (air or gas) stream.
Combustion takes place in the bed with high heat transfer to the furnace and low combustion temperatures.
The document discusses two options to improve super heaters in AFBC boilers. The first option is designing radiant super heaters that avoid problems with bed super heaters like clinker formation and space constraints. Radiant super heaters have a longer replacement period of 25 years. The second option is coating existing bed super heater tubes with infiltration brazed tungsten carbide cladding, which reduces corrosion and erosion while increasing tube life four times. Both options greatly increase super heater availability.
This document provides an overview of industrial, commercial, and institutional (ICI) boilers. It discusses how boilers work to convert the chemical energy in fuel into thermal energy. ICI boilers come in various sizes and configurations depending on their fuel source and required output. They are generally classified as either firetube or watertube boilers. Firetube boilers have tubes that combustion gases flow through to heat surrounding water, while watertube boilers circulate gases around outside of water-filled tubes. The document describes common types of firetube and watertube boilers and their typical fuel sources.
This document discusses steam generators (boilers) and is divided into three parts. The first part covers introduction and types of steam generators. The second part discusses the parts, accessories, and auxiliaries of steam generators. The third part covers the design, efficiency, performance, and protection of steam generators. It provides details on classification, fundamental design considerations, combustion processes, fuel analysis, boiler efficiency calculation methods, and factors that influence boiler performance such as heat losses.
Boilers have several uses including generating steam to drive turbines for electricity production, and to provide steam for heating, cooling and industrial processes. Boilers can be classified based on their orientation, water and gas flow design, furnace location, circulation method, pressure rating, mobility, and number of tubes. Common boiler types include fire tube boilers like Cochran and Lancashire where gases pass through tubes and water surrounds them, and water tube boilers like Babcock & Wilcox where water passes through tubes and gases surround them. Each boiler type has advantages like efficiency, capacity, and cost, but also limitations regarding pressure, size, and complexity.
The document provides an overview of steam generation and steam generators. It discusses how steam generators convert water into steam through boiling for applications like power generation and industrial heating. Steam generators can range in size from small package boilers producing 1000 lb/h of steam to large utility boilers producing over 10 million lb/h. Key components of steam generation systems include the steam generator, turbines, condensers, pumps, and sometimes nuclear reactors or pollution control devices.
A boiler is a device that generates steam by transferring heat from burning fuel to water. There are two main types: fire-tube boilers where hot gases pass through tubes surrounded by water, and water-tube boilers where water passes through tubes surrounded by hot gases. Boilers have many applications including power generation, heating, and industrial processes. Key factors in boiler selection include required steam properties, size, cost, and fuel/water availability. Boilers are also classified based on design features such as tube layout, firing method, pressure, and circulation.
A boiler is a closed vessel that transfers heat from fuel combustion to water, converting it into steam for power generation, industrial processes, and heating. Boilers are classified based on their heat source, circulation method, orientation, and whether they are stationary or mobile. A boiler is a mechatronics system that uses sensors to monitor heat, water level, and pressure, sending signals to a control unit consisting of a microcontroller and other components that regulate the system without human interference through actuators like water valves.
This document discusses boiler blowdown, which is the process of removing concentrated boiler water and replacing it with fresh feedwater. It provides information on:
- Common impurities in raw water that can cause scaling, sludge, corrosion, or foaming in boilers.
- Guidelines for maximum total dissolved solids levels in boiler water depending on boiler type to avoid issues.
- A formula for calculating the required blowdown rate to maintain a target boiler water total dissolved solids level based on feedwater quality and boiler steam rate.
- An example calculation of the blowdown rate required for a specific boiler operating at 10,000 kg/h steam with 250 ppm feedwater to maintain 2,500
This document discusses safety measures, systems, and certification for industries. It covers the need for safety instrumented systems (SIS) in high-risk industries like oil and gas. The basics of SIS include safety instrumented functions (SIF), safety integrity levels (SIL), and international standards. The document outlines the design, analysis, and implementation of SIS, including probability of failure on demand, redundancy, and typical examples like emergency shutdown systems and fire and gas systems. The goal is to systematically ensure safety in industrial operations.
Industrial Attachment Program (IAP) ReportAkshit Arora
Project report for IAP, project developed for automating the Industrial Attachment Program of Dept. of Mechanical Engineering at Thapar University. Developed under the guidance of Dr. Ajay Batish (Professor at Mechanical Engg. Dept, TU)
Wheat is a tan-colored plant that grows 4 feet tall with long, thin stems and flowers. It thrives in mild, moist climates and provides many nutritional benefits as a food source in items like bread, pasta, and muffins. Wheat also reduces risk of metabolic syndrome and type 2 diabetes.
This short document discusses a song by Gerry and the Pacemakers called "You'll Never Walk Alone". The music referenced is from that song. The document was created by Edna and includes her email.
This document contains a 31 page mathematics examination paper for SPM 2013. It includes 19 multiple choice questions related to mathematical formulas, shapes and space, algebra, trigonometry, and coordinate geometry. The questions require calculations, applying formulas, analyzing diagrams, and expressing algebraic expressions in simplest form.
Power Rabbit is an energy drink and bar company headquartered in Kristiansund, Norway with 20 stores across Europe. Their target audiences are generally people who like energy products and those aged 18-30, especially athletes. They primarily use social media like Facebook, Instagram, Twitter and Snapchat to communicate with these audiences multiple times per week, providing value through videos, new product announcements, articles and contests. They also partner with athletes and celebrities to promote their brand through endorsements, giveaways and sponsored events. Their focus is on providing fast, credible customer service across all platforms to meet audience expectations and build closer relationships with customers.
The document provides information about the Better Metal BHH-1K-24C cantilever horsehead product. It describes how to purchase the product from Launch 3 Telecom, including payment and shipping options. It also details the warranty and services provided by Launch 3 Telecom such as repairs, maintenance contracts, de-installation, and recycling.
Este documento describe un plan de clases para estudiantes de tercer grado sobre la entidad de Sinaloa, México. El objetivo es que los estudiantes identifiquen los límites territoriales de Sinaloa y reconozcan las diversas actividades económicas de la entidad. La lección incluye ver un video sobre Sinaloa, armar rompecabezas de los municipios, y jugar un memorama sobre las actividades económicas de cada municipio. El plan evalúa si los estudiantes pueden reconocer las áreas del video, identificar los límites
The document provides information on different types of boilers. It discusses fire tube boilers which have tubes that hot combustion gases pass through to heat surrounding water. Water tube boilers are also described, where water passes through tubes surrounded by hot gases. Modern power station boilers are large water tube boilers with sections for combustion, steam generation, and heat recovery units like superheaters and economizers. Different boiler components like the furnace, drum, and circuits for water, steam, and air/gas are also summarized.
The document provides information on different types of boilers. It discusses fire tube boilers which have tubes that hot combustion gases pass through to heat surrounding water. Water tube boilers are also described, where water passes through tubes surrounded by hot gases. Modern power station boilers are large water tube boilers with sections for combustion, steam generation, and heat recovery units like superheaters and economizers. Different boiler components like the furnace, drum, and circuits for water, steam, and air/gas are also summarized.
The document discusses fluidized bed combustion (FBC) boilers. It describes the mechanism of FBC, including how fluidization works. It outlines the main types of FBC boilers: atmospheric fluidized bed combustion, circulating fluidized bed combustion, and pressurized fluidized bed combustion. The document highlights the advantages of FBC boilers such as their ability to burn a wide range of low-grade fuels efficiently with low emissions. It also discusses operational features, retrofitting FBC systems, and challenges like corrosion.
The document discusses fluidized bed combustion (FBC) boilers. It describes the key advantages of FBC boilers like their ability to efficiently burn low quality coal and reduce emissions. It explains the basic mechanisms of fluidization and combustion. There are three main types of FBC boilers - atmospheric fluidized bed combustion, circulating fluidized bed combustion, and pressurized fluidized bed combustion. The document provides details on the design and operating principles of atmospheric fluidized bed combustion boilers.
Steam generators (boilers) are complex systems that integrate components like furnaces, superheaters, reheaters, boilers, and economizers to generate steam. They can be classified based on application (e.g. utility, industrial), pressure level (subcritical or supercritical), tube movement design (fire tube or water tube), and firing method (externally or internally fired). Modern utility steam generators commonly operate between 130-180 bar pressure to produce superheated steam at 540-560°C with one or two stages of reheating. Pulverized coal is a common fuel that is finely ground and blown into a furnace through burners to facilitate more complete and efficient combustion.
This document discusses fluidized bed combustion boilers. It begins with an introduction that fluidized bed combustion has emerged as a viable alternative to traditional grate firing systems for low quality coal in India. It provides a brief history of the development of fluidized bed combustion. It then describes the three main types of fluidized bed combustion boilers and the basic mechanism of how fluidized bed combustion works. The document proceeds to describe the key components of a circulating fluidized bed combustion system and provides maintenance tips for inspecting and maintaining a CFB boiler.
different type of boiler & combustion in boilersShowhanur Rahman
The document describes three types of boilers: fire tube boilers, water tube boilers, and waterwall boilers. Fire tube boilers have hot gases passing through tubes surrounded by water, can generate lower pressure steam at a slower rate, and are less efficient than water tube boilers. Water tube boilers circulate water inside tubes surrounded by hot gases, can generate higher pressure steam at a faster rate, and are more efficient. Waterwall boilers have water tubes forming the furnace walls to allow for lighter boiler construction.
This document provides an overview of a circulating fluidized bed boiler used for power generation. It discusses the key components and operating principles of the boiler, including:
- The boiler uses crushed coal injected into a furnace where it is fluidized and suspended in upward air flow, allowing for combustion. Limestone is also used to control emissions.
- Hot gases and partially burned fuel particles circulate from the furnace to a cyclone where particles are separated and returned to the furnace.
- Water circulates through drums, water walls and other components where it is converted to steam through absorption of heat from combustion. Steam is then sent to a turbine for power generation.
- Startup and operation procedures
Boilers and its types systems and boilers water treatment Salman Jailani
The document discusses different types of boilers and their classifications. It begins with an introduction to boilers, describing them as enclosed vessels that provide combustion heat transfer to water or steam.
It then summarizes the main types of boilers as fire tube boilers, water tube boilers, and packaged boilers. Fire tube boilers contain tubes through which hot gases pass and water circulates around. Water tube boilers reverse this configuration. Packaged boilers are complete pre-assembled units.
The document also covers boiler systems, components, and classifications based on fuel type like stokers and pulverized fuel. Performance evaluation methods like efficiency calculations via direct and indirect methods are summarized.
Types, Combustion in boilers, Performances evaluation, Analysis of losses, Feed
water treatment, Blow down, Energy conservation opportunities.
Types, Combustion in boilers, Performances evaluation, Analysis of losses, Feed
water treatment, Blow down, Energy conservation opportunities.
The document discusses fluidized bed combustion, which involves suspending solid fuel particles in a gas stream to create a fluid-like mixture that allows for more efficient combustion. It then explains the working of fluidized bed combustion systems and their advantages over conventional combustion, such as lower emissions and the ability to burn fuels with higher ash content. Key components of steam power plants like boilers, turbines, and condensers are also described.
Steam generators/boilers convert the chemical energy of fossil fuels into thermal energy, which is then transferred to water to produce high-pressure steam. There are various types of steam generators classified by capacity, pressure, design, and heating surface arrangement. Key boiler types discussed include fire tube boilers, water tube boilers, locomotive boilers, Babcock and Wilcox boilers, and Cochran boilers. Selection of boilers depends on factors like codes and standards, load requirements, number of boilers needed, and special considerations like space and replacement needs.
This document summarizes a study conducted at a power plant in India to optimize bed material consumption during start-up of circulating fluidized bed combustion (CFBC) boilers. Conventionally, new bed material was used for each start-up, but the study proposed using bed ash instead, finding it had comparable properties. Implementing this change eliminated costs associated with purchasing new bed material, transportation, and lost unused coal in the ash. The plant was able to successfully use 100% bed ash instead of new bed material, saving over Rs. 1.46 lakh per start-up.
The document discusses steam generators or boilers. It begins by defining a steam generator or boiler as a closed vessel made of steel that transfers heat from combustion of a fuel to water to ultimately generate steam. The steam can then be used to power steam engines and turbines or for industrial processes or heating. The document goes on to describe key components of boilers, classifications of boilers, essential characteristics of good boilers, factors for boiler selection, and common boiler mountings and accessories.
This document provides information on different types of boilers and their components. It discusses fire tube boilers and water tube boilers. It also describes auxiliary equipment that can be fitted to boilers like pressure gauges, water gauge glasses, and pressure relief valves. Additionally, it covers topics like superheaters, economizers, different types of fuel firing systems, evaporation, heat pipes, and performance measures for tubular evaporators.
This document provides information on different types of boilers and their components. It discusses fire tube boilers and water tube boilers. It also describes auxiliary equipment that can be fitted to boilers like pressure gauges, water gauge glasses, and pressure relief valves. Additionally, it covers topics like superheaters, economizers, coal firing, gas firing, evaporation, heat pipes, and performance of tubular evaporators.
Boiler definition types applications necessity and fuel used with pdf (1)BhaveshMhaskar
Boilers are closed vessels that convert water into steam by heating it under pressure. They are classified based on their circulation method (fire tube or water tube), circulation of water (free or forced), number of tubes, intended use, fuel type, operating pressure, and orientation. Boilers are necessary as the central heating mechanism for buildings, using combustion to generate steam or hot water that is distributed throughout the structure via pumps, radiators, and heat exchangers. They serve essential functions for industrial processes, power generation, and heating applications.
CFB boiler presentation In which you will learn all about CFB boilerabdulrahimchohan865
The document describes the key components and operation of a circulating fluidized bed (CFB) boiler. The CFB boiler combusts crushed coal between 20-50mm in size using fluidized air. Unburnt coal is returned to the furnace through a cyclone separator. The main components are the furnace, cyclone separator, back pass, and air preheater. In the furnace, coal is combusted and limestone is added to reduce SOx emissions. The cyclone separator separates unburnt particles from flue gas. Heat from flue gas is transferred in the back pass to produce steam. The air preheater improves efficiency by preheating combustion air.
COAL BASED THERMAL POWER PLANTS (UNIT-1).pptxCHANDRA KUMAR S
Thermal power plants convert the chemical energy stored in fossil fuels into heat energy by burning coal. The heat boils water to produce steam, which powers turbines that generate electricity. There are four main circuits in a thermal power plant: coal and ash, air and flue gas, water and steam, and cooling water. Coal is burned to heat water and produce steam, which spins turbines to generate electricity. The resulting ash is removed and stored while flue gases are treated before being released into the atmosphere.
The document discusses different methods of solid fuel combustion, including coal combustion. It describes three stages of coal combustion: drying, devolatilization, and char combustion. It then discusses different coal combustion systems like fixed beds (including overfeed and underfeed stokers), fluidized beds (bubbling and circulating), and pulverized coal combustion. For fluidized beds, it provides details on bubbling fluidized beds and pressurized fluidized bed combustion.
Similar to Boilerintroduction 130518020407-phpapp01 (20)
3. Boiler-
A ‘Boiler’ means a pressure vessel in which steam is generated
for use external to itself by application of heat which is wholly
or partly under pressure when steam is shut off but does not
include a pressure vessel
(1) With Capacity less than 25 ltrs (such capacity being
measured from the feed check valve to the main steam stop
valve);
(2) With less than 1 kilogram per centimeter square design
gauge pressure & working gauge pressure; or
(3) In which water is heated below one hundred degree
centigrade .
4. ‘Boiler component’ means Steam piping , Feed water piping,
Economizer ,Super heater, any mounting or other fitting and
any other external or internal part of a Boiler which is
subjected to pressure exceeding one kilogram per centimeter
square gauge.
5. “Steam Pipe "means any pipe through which steam passes if-
(1)The pressure at which the steam passes through such pipe
exceeds 3.5kg/cm^2 above atmospheric pressure, or
(2)Such pipe exceeds 254 mm in internal diameter and pressure
of steam exceeds 1kg/cm^2.above the atmospheric pressure.
and includes in either case any connected fitting of a
steam pipe.
6. At atmospheric pressure water volume increases
1,600 times
BURNER
WATER
SOURCE
SOFTENERS
CHEMICAL FEED
FUEL
BLOW DOWN
SEPARATOR
VENT
STACK DEAERATOR
PUMPS
BOILER
ECO-
NOMI-
ZER
VENTEXHAUST GAS
STEAM TO
PROCESS
Figure: Schematic overview of a boiler room
7. Boiler Systems
Flue gas system
Water treatment system
Feed water system
Steam System
Blow down system
Fuel supply system
Air Supply system
8. Fuels used in Boiler
S.No
Solid Liquid Gaseous AgroWaste
1 Coal HSD NGas Baggase
2 Lignite LDO Bio Gas Pith
3 Charcoal Fur.Oil Rice Husk
4 LSHS Paddy Straw
5 Coconut shell
6 Groundnutshell
MSW/RDF
9. Types of Boilers
1. Fire Tube Boiler
2. Water Tube Boiler
3. Packaged Boiler
4. Stoker Fired Boiler
5. Pulverized Fuel Boiler
6. Waste Heat Boiler
7. Fluidized Bed (FBC) Boiler
10. Type of Boilers
(Light Rail Transit Association)
1. Fire Tube Boiler
• Relatively small
steam capacities
(12,000 kg/hour)
• Low to medium
steam pressures
(18 kg/cm2)
• Operates with oil,
gas or solid fuels
11. Type of Boilers
2. Water Tube Boiler
(Your Dictionary.com)
• Used for high steam
demand and pressure
requirements
• Capacity range of 4,500
– 120,000 kg/hour
• Combustion efficiency
enhanced by induced
draft provisions
• Lower tolerance for
water quality and needs
water treatment plant
12. Type of Boilers
(BIB Cochran, 2003)
3. Packaged Boiler
Oil
Burner
To Chimney • Comes in complete
package
• Features
• High heat transfer
• Faster evaporation
• Good convective
heat transfer
• Good combustion
efficiency
• High thermal
efficiency
• Classified based on
number of passes
13. Type of Boilers
4. Stoke Fired Boilers
a) Spreader stokers
Uses both suspension and
grate burning
Coal fed continuously over
burning coal bed
Coal fines burn in suspension
and larger coal pieces burn on
grate
Good flexibility to meet
changing load requirements
Preferred over other type of
stokers in industrial
application
14. Type of Boilers
4. Stoke Fired Boilers
b) Chain-grate or traveling-
grate stoker
(University of Missouri, 2004)
Uses both suspension and
grate burning
Coal fed continuously over
burning coal bed
Coal fines burn in
suspension and larger coal
pieces burn on grate
Good flexibility to meet
changing load
requirements
Preferred over other type
of stokers in industrial
application
15. Type of Boilers
Tangential firing
5. Pulverized Fuel Boiler
• Pulverized coal powder blown with
combustion air into boiler through
burner nozzles
• Combustion temperature at 1300 -1700
°C
• Benefits: varying coal quality coal,
quick response to load changes and
high pre-heat air temperatures
Coal is pulverized to a fine powder, so that less than 2% is +300
microns, and 70-75% is below 75 microns.
Coal is blown with part of the combustion air into the boiler plant
through a series of burner nozzles.
16. Advantages
Its ability to burn all ranks of coal from anthracitic to
lignitic, and it permits combination firing (i.e., can
use coal, oil and gas in same burner). Because of
these advantages, there is widespread use of
pulverized coal furnaces.
Disadvantages
High power demand for pulverizing
Requires more maintenance, flyash erosion and
pollution complicate unit operation
Pulverized Fuel Boiler (Contd..)
17. Type of Boilers
Agriculture and Agri-Food
Canada, 2001
6. Waste Heat Boiler
• Used when waste heat
available at medium/high
temp
• Auxiliary fuel burners
used if steam demand is
more than the waste heat
can generate
• Used in heat recovery
from exhaust gases from
gas turbines and diesel
engines
18. 7.Fluidized Bed (FBC) Boiler
An Overview-
Fluidized bed combustion has emerged as a viable
alternative and has significant advantages over
conventional firing system and offers multiple benefits –
compact boiler design, fuel flexibility, higher combustion
efficiency and reduced emission of noxious pollutants
such as SOx and NOx. The fuels burnt in these boilers
include coal, washery rejects, rice husk, bagasse & other
agricultural wastes. The fluidized bed boilers have a wide
capacity range.
19. Mechanism of Fluidised Bed Combustion
When an evenly distributed air or gas is passed upward
through a finely divided bed of solid particles such as sand
supported on a fine mesh, the particles are undisturbed at low
velocity. As air velocity is gradually increased, a stage is
reached when the individual particles are suspended in the air
stream – the bed is called “fluidized”.
With further increase in air velocity, there is bubble
formation, vigorous turbulence, rapid mixing and
formation of dense defined bed surface. The bed of solid
particles exhibits the properties of a boiling liquid and
assumes the appearance of a fluid – “bubbling fluidized
bed”.
20. At higher velocities, bubbles disappear, and particles are
blown out of the bed. Therefore, some amounts of particles
have to be recirculated to maintain a stable system –
“circulating fluidised bed”.
Fluidization depends largely on the particle size and the air
velocity.
If sand particles in a fluidized state is heated to the ignition
temperatures of coal, and coal is injected continuously into
the bed, the coal will burn rapidly and bed attains a uniform
temperature. The fluidized bed combustion (FBC) takes
place at about 840OC to 950OC.
21. Since this temperature is much below the ash fusion temperature,
melting of ash and associated problems are avoided.
The lower combustion temperature is achieved because of high
coefficient of heat transfer due to rapid mixing in the fluidized bed
and effective extraction of heat from the bed through in-bed heat
transfer tubes and walls of the bed. The gas velocity is maintained
between minimum fluidisation velocity and particle entrainment
velocity. This ensures stable operation of the bed and avoids particle
entrainment in the gas stream.
Combustion process requires the three “T”s that is Time, Temperature and
Turbulence. In FBC, turbulence is promoted by fluidisation. Improved
mixing generates evenly distributed heat at lower temperature. Residence
time is many times greater than conventional grate
firing. Thus an FBC system releases heat more efficiently at lower
temperatures.
22. Fixing, bubbling
and fast fluidized
beds
As the velocity of a
gas flowing through
a bed of particles
increases, a value is
reaches when the
bed fluidises and
bubbles form as in a
boiling liquid. At
higher velocities the
bubbles disappear;
and the solids are
rapidly blown out of
the bed and must be
recycled to maintain
a stable system.
principle of fluidisation
23. Since limestone is used as particle bed, control of sulfur dioxide and nitrogen
oxide emissions in the combustion chamber is achieved without any additional
control equipment. This is one of the major advantages over conventional
boilers.
Types of Fluidised Bed Combustion Boilers
There are three basic types of fluidised bed combustion boilers:
1. Atmospheric classic Fluidised Bed Combustion System (AFBC)
2. Pressurised Fluidised Bed Combustion System (PFBC).
3. Circulating (fast) Fluidised Bed Combustion system(CFBC)
24. AFBC / Bubbling Bed
In AFBC, coal is crushed to a size of 1 – 10 mm depending on the rank of
coal, type of fuel feed and fed into the combustion chamber. The
atmospheric air, which acts as both the fluidization air and combustion
air, is delivered at a pressure and flows through the bed after being
preheated by the exhaust flue gases. The velocity of fluidising air is in the
range of 1.2 to 3.7 m /sec. The rate at which air is blown through the bed
determines the amount of fuel that can be reacted.
Almost all AFBC/ bubbling bed boilers use in-bed evaporator tubes
in the bed of limestone, sand and fuel for extracting the heat from
the bed to maintain the bed temperature. The bed depth is usually 0.9
m to 1.5 m deep and the pressure drop averages about 1 inch of water per
inch of bed depth. Very little material leaves the bubbling bed – only about
2 to 4 kg of solids are recycled per ton of fuel burned.
25. Bubbling Bed Boilers
In the bubbling bed type boiler, a layer of solid particles
(mostly limestone, sand, ash and calcium sulfate) is
contained on a grid near the bottom of the boiler. This layer
is maintained in a turbulent state as low velocity air is forced
into the bed from a plenum chamber beneath the grid. Fuel
is added to this bed and combustion takes place. Normally,
raw fuel in the bed does not exceed 2% of the total bed
inventory. Velocity of the combustion air is kept at a
minimum, yet high enough to maintain turbulence in the
bed. Velocity is not high enough to carry significant
quantities of solid particles out of the furnace.
26. This turbulent mixing of air and fuel results in a residence time of up to five
seconds. The combination of turbulent mixing and residence time permits
bubbling bed boilers to operate at a furnace temperature below 1650°F. At
this temperature, the presence of limestone mixed with fuel in the furnace
achieves greater than 90% sulfur removal. Boiler efficiency is the percentage
of total energy in the fuel that is used to produce steam. Combustion
efficiency is the percentage of complete combustion of carbon in the fuel.
Incomplete combustion results in the formation of carbon monoxide (CO)
plus unburned carbon in the solid particles leaving the furnace. In a typical
bubbling bed fluidized boiler, combustion efficiency can be as high as
92%. This is a good figure, but is lower than that achieved by
pulverized coal or cyclone-fired boilers. In addition, some fuels that are
very low in volatile matter cannot be completely burned within the
available residence time in bubbling bed-type boilers.
27. Features of bubbling bed boiler
Fluidised bed boiler can operate at near atmospheric or elevated
pressure and have these essential features:
• Distribution plate through which air is blown for fluidizing.
• Immersed steam-raising or water heating tubes which extract heat
directly from the bed.
• Tubes above the bed which extract heat from hot combustion gas
before it enters the flue duct.
33. 2. Pressurised Fluidised Bed Combustion
System (PFBC).
Pressurised Fluidised Bed Combustion (PFBC) is a variation of fluid bed
technology that is meant for large-scale coal burning applications. In
PFBC, the bed vessel is operated at pressure up to 16 ata ( 16 kg/cm2).
The off-gas from the fluidized bed combustor drives the gas turbine. The
steam turbine is driven by steam raised in tubes immersed in the fluidized
bed. The condensate from the steam turbine is pre-heated using waste
heat from gas turbine exhaust and is then taken as feed water for steam
generation.
The PFBC system can be used for cogeneration or combined cycle power
generation. By combining the gas and steam turbines in this way,
electricity is generated more efficiently than in conventional system. The
overall conversion efficiency is higher by 5% to 8%. .
At elevated pressure, the potential reduction in boiler size is considerable
due to increased amount of combustion in pressurized mode and high
heat flux through in-bed tubes.
35. 3. Circulating (fast) Fluidised Bed Combustion
system(CFBC)
The need to improve combustion efficiency (which also increases overall
boiler efficiency and reduces operating costs) and the desire to burn a
much wider range of fuels has led to the development and
application of the CFB boiler. Through the years, boiler suppliers have
been increasing the size of these high-efficiency steam generators.
This CFBC technology utilizes the fluidized bed principle in which
crushed (6 –12 mm size) fuel and limestone are injected into the furnace
or combustor. The particles are suspended in a stream of upwardly
flowing air (60-70% of the total air), which enters the bottom of the
furnace through air distribution nozzles. The fluidising velocity in
circulating beds ranges from 3.7 to 9 m/sec. The balance of combustion
air is admitted above the bottom of the furnace as secondary air.
36. The combustion takes place at 840-900oC, and the fine particles (<450
microns) are elutriated out of the furnace with flue gas velocity of 4-6 m/s.
The particles are then collected by the solids separators and circulated back
into the furnace. Solid recycle is about 50 to 100 kg per kg of fuel burnt.
There are no steam generation tubes immersed in the bed. The circulating
bed is designed to move a lot more solids out of the furnace area and to
achieve most of the heat transfer outside the combustion zone - convection
section, water walls, and at the exit of the riser. Some circulating bed units
even have external heat exchanges.
The particles circulation provides efficient heat transfer to the furnace
walls and longer residence time for carbon and limestone utilization.
Similar to Pulverized Coal (PC) firing, the controlling parameters in the
CFB combustion process are temperature, residence time and turbulence.
37. For large units, the taller furnace characteristics of CFBC boiler offers
better space utilization, greater fuel particle and sorbent residence time for
efficient combustion and SO2 capture, and easier application of staged
combustion techniques for NOx control than AFBC generators. CFBC
boilers are said to achieve better calcium to sulphur utilization – 1.5 to 1 vs.
3.2 to 1 for the AFBC boilers, although the furnace temperatures are almost
the same.
CFBC boilers are generally claimed to be more economical than AFBC
boilers for industrial application requiring more than 75 – 100 T/hr of
steam
CFBC requires huge mechanical cyclones to capture and recycle the large
amount of bed material, which requires a tall boiler.
A CFBC could be good choice if the following conditions are met.
1. Capacity of boiler is large to medium
2.Sulphur emission and NOx control is important
3.The boiler is required to fire low-grade fuel or fuel with highly
fluctuating fuel quality.
38.
39.
40. Circulating bed boiler (At a Glance)-
At high fluidizing gas velocities in which a fast recycling bed of fine
material is superimposed on a bubbling bed of larger particles. The
combustion temperature is controlled by rate of recycling of fine
material. Hot fine material is separated from the flue gas by a cyclone and
is partially cooled in a separate low velocity fluidized bed heat exchanger,
where the heat is given up to the steam. The cooler fine material is then
recycled to the dense bed.
41. Advantages of Fluidised Bed Combustion Boilers
1. High Efficiency
FBC boilers can burn fuel with a combustion efficiency of over 95% irrespective
of ash content. FBC boilers can operate with overall efficiency of 84% (plus or
minus 2%).
2. Reduction in Boiler Size
High heat transfer rate over a small heat transfer area immersed in the bed
result in overall size reduction of the boiler.
3. Fuel Flexibility
FBC boilers can be operated efficiently with a variety of fuels. Even fuels like
flotation slimes, washer rejects, agro waste can be burnt efficiently. These can be
fed either independently or in combination with coal into the same furnace.
4. Ability to Burn Low Grade Fuel
FBC boilers would give the rated output even with inferior quality fuel. The
boilers can fire coals with ash content as high as 62% and having calorific value
as low as 2,500 kcal/kg. Even carbon content of only 1% by weight can sustain
the fluidised bed combustion.
42. 5. Ability to Burn Fines
Coal containing fines below 6 mm can be burnt efficiently in FBC boiler,
which is very difficult to achieve in conventional firing system.
6. Pollution Control
SO2 formation can be greatly minimised by addition of limestone or dolomite
for high sulphur coals. 3% limestone is required for every 1% sulphur in the
coal feed. Low combustion temperature eliminates NOx formation.
7. Low Corrosion and Erosion
The corrosion and erosion effects are less due to lower combustion
temperature, softness of ash and low particle velocity (of the order of 1
m/sec).
8. Easier Ash Removal – No Clinker Formation
Since the temperature of the furnace is in the range of 750 – 900o C in FBC
boilers, even coal of low ash fusion temperature can be burnt without clinker
formation. Ash removal is easier as the ash flows like liquid from the
combustion chamber. Hence less manpower is required for ash handling.
43. 9. Less Excess Air –
Higher CO2 in Flue Gas The CO2 in the flue gases will be of the order of 14 – 15% at
full load. Hence, the FBC boiler can operate at low excess air - only 20 – 25%.
10. Simple Operation, Quick Start-Up
High turbulence of the bed facilitates quick start up and shut down. Full
automation of start up and operation using reliable equipment is possible.
11. Fast Response to Load Fluctuations
Inherent high thermal storage characteristics can easily absorb fluctuation in fuel
feed rates. Response to changing load is comparable to that of oil fired boilers.
12. No Slagging in the Furnace-No Soot Blowing
In FBC boilers, volatilisation of alkali components in ash does not take place and the
ash is non sticky. This means that there is no slagging or soot blowing.
13 Provisions of Automatic Coal and Ash Handling System
Automatic systems for coal and ash handling can be incorporated, making the plant
easy to operate comparable to oil or gas fired installation.
44. 14 Provision of Automatic Ignition System
Control systems using micro-processors and automatic ignition equipment
give excellent control with minimum manual supervision.
15 High Reliability
The absence of moving parts in the combustion zone results in a high
degree of reliability and low maintenance costs.
16 Reduced Maintenance
Routine overhauls are infrequent and high efficiency is maintained for long
periods.
17 Quick Responses to Changing Demand
A fluidized bed combustor can respond to changing heat demands more
easily than stoker fired systems. This makes it very suitable for applications
such as thermal fluid heaters, which require rapid responses.
18 High Efficiency of Power Generation
By operating the fluidized bed at elevated pressure, it can be used to
generate hot pressurized gases to power a gas turbine. This can be
combined with a conventional steam turbine to improve the
efficiency of electricity generation and give a potential fuel savings
of at least 4%.
45.
46.
47. General Arrangements of FBC Boiler
FBC boilers comprise of following systems:
i) Fuel feeding system
ii) Air Distributor
iii) Bed & In-bed heat transfer surface
iv) Ash handling system
Many of these are common to all types of FBC boilers
1. Fuel Feeding system
For feeding fuel, sorbents like limestone or dolomite, usually two methods
are followed: under bed pneumatic feeding and over-bed feeding.
Under Bed Pneumatic Feeding
If the fuel is coal, it is crushed to 1-6 mm size and pneumatically
transported from feed hopper to the combustor through a feed pipe
piercing the distributor. Based on the capacity of the boiler, the number of
feed points is increased, as it is necessary to distribute the fuel into the
bed uniformly.
48. Over-Bed Feeding
The crushed coal, 6-10 mm size is conveyed from coal bunker to a spreader by a
screw conveyor. The spreader distributes the coal over the surface of the bed
uniformly. This type of fuel feeding system accepts over size fuel also and
eliminates transport lines, when compared to under-bed feeding system.
2. Air Distributor
The purpose of the distributor is to introduce the fluidizing air evenly through the
bed cross section thereby keeping the solid particles in constant motion, and
preventing the formation of defluidization zones within the bed. The distributor,
which forms the furnace floor, is normally constructed from metal plate with a
number of perforations in a definite geometric pattern. The perforations may be
located in simple nozzles or nozzles with bubble caps, which serve to prevent
solid particles from flowing back into the space below the distributor.
The distributor plate is protected from high temperature of the furnace by:
i) Refractory Lining
ii) A Static Layer of the Bed Material or
iii) Water Cooled Tubes.
49. 3. Bed & In-Bed Heat Transfer Surface:
a) Bed
The bed material can be sand, ash, crushed refractory or limestone, with an
average size of about 1 mm. Depending on the bed height these are of two types:
shallow bed and deep bed.
At the same fluidizing velocity, the two ends fluidise differently, thus affecting the
heat transfer to an immersed heat transfer surfaces. A shallow bed offers a lower
bed resistance and hence a lower pressure drop and lower fan power consumption.
In the case of deep bed, the pressure drop is more and this increases the effective
gas velocity and also the fan power.
b) In-Bed Heat Transfer Surface
In a fluidized in-bed heat transfer process, it is necessary to transfer heat between
the bed material and an immersed surface, which could be that of a tube bundle,
or a coil. The heat exchanger orientation can be horizontal, vertical or inclined.
From a pressure drop point of view, a horizontal bundle in a shallow bed is more
attractive than a vertical bundle in a deep bed. Also, the heat transfer in the bed
depends on number of parameters like (i) bed pressure (ii) bed temperature (iii)
superficial gas velocity (iv) particle size (v) Heat exchanger design and (vi) gas
distributor plate design.
50. 4. Ash Handling System
a) Bottom ash removal
In the FBC boilers, the bottom ash constitutes roughly 30 - 40 % of the total ash,
the rest being the fly ash. The bed ash is removed by continuous over flow to
maintain bed height and also by intermittent flow from the bottom to remove
over size particles, avoid accumulation and consequent defluidization. While
firing high ash coal such as washery rejects, the bed ash overflow drain quantity is
considerable so special care has to be taken.
b) Fly ash removal
The amount of fly ash to be handled in FBC boiler is relatively very high, when
compared to conventional boilers. This is due to elutriation of particles at high
velocities. Fly ash carried away by the flue gas is removed in number of stages;
firstly in convection section, then from the bottom of air preheater/economizer
and finally a major portion is removed in dust collectors.
The types of dust collectors used are cyclone, bagfilters, electrostatic
precipitators (ESP’s) or some combination of all of these. To increase the
combustion efficiency, recycling of fly ash is practiced in some of the units.
51. General Features of our Project(3nos)
Installed Capacity : 1 X 15 MW
Proposed Fuels : 85 % of Bagasse / Biomass, 15 % of Coal, Pet
Coke.
Boiler Type : Circulating Fluidized Bed Combustion
(CFBC)
Boiler parameters : Flow – 75 TPH
Pressure – 87 Kg/cm^2
Temperature - 515 ± 5 oC
Turbine Type : Two Nos. of uncontrolled extraction type and
one no. of controlled extraction cum
condensing type
Turbine parameters : Pressure – 84 Kg/cm^2
Temperature - 510 ± 5 oC
Plant load Factor : 0.85
No. of Days of power: 335
plant operation in a year
52. General Features of our Project(1nos)
Installed Capacity : 1 X 15 MW
Proposed Fuels : 85 % of Bagasse / Biomass, 15 % of Coal, Pet
Coke.
Boiler Type : Circulating Fluidized Bed Combustion
(CFBC)
Boiler parameters : Flow – 100 TPH
Pressure – 87 Kg/cm^2
Temperature - 515 ± 5 oC
Turbine Type : Two Nos. of uncontrolled extraction type and
one no. of controlled extraction cum
condensing type
Turbine parameters : Pressure – 84 Kg/cm^2
Temperature - 510 ± 5 oC
Plant load Factor : 0.85
No. of Days of power: 335
plant operation in a year
53. 600 MWe
OTU CFB.
Using the
BENSON
Vertical
technology,
Foster
Wheeler
has
developed a
design for a
600 MWe
supercritical
CFB boiler
Future of CFBC Boiler
54.
55. FOSTER WHEELER AWARDED CONTRACT FOR
WORLD’S LARGEST 100% BIOMASS BOILER
ZUG, SWITZERLAND, April 7, 2010 - Foster Wheeler AG (Nasdaq: FWLT)
announced today that its Global Power Group has been awarded a contract
by GDF SUEZ, one of the leading energy providers in the world, for the
design, supply and erection of a 190 MWe (gross megawatt electric) 100%
biomass-fired circulating fluidized-bed (CFB) boiler island for the Polaniec
Power Station in Poland.
Foster Wheeler has received a full notice to proceed on this contract which
will be executed jointly by its subsidiaries in Finland and Poland. The terms
of the agreement were not disclosed and the contract value will be included
in the company’s bookings for the first quarter of 2010. Construction
completion and start of operation of the new steam generator is scheduled
for fourth-quarter 2012.
Foster Wheeler will design and supply the steam generator and auxiliary
equipment, including biomass yard, and will carry out the civil works,
erection and commissioning of the boiler island. Once complete, this will be
the world’s largest biomass boiler burning wood residues and up to 20% agro
biomass.
56. 1. Boiler
2. Boiler blow down
3. Boiler feed water treatment
Performance of a boiler
57. Performance of a Boiler
1. Boiler performance
• Causes of poor boiler performance
-Poor combustion
-Heat transfer surface fouling
-Poor operation and maintenance
-Deteriorating fuel and water quality
• Heat balance: identify heat losses
• Boiler efficiency: determine
deviation from best efficiency
58. Performance of a Boiler
Heat Balance
An energy flow diagram describes geographically
how energy is transformed from fuel into useful
energy, heat and losses
Stochiometric
Excess Air
Un burnt
FUEL INPUT STEAM
OUTPUT
Stack Gas
Ash and Un-burnt parts
of Fuel in Ash
Blow
Down
Convection &
Radiation
59. Performance of a Boiler
Heat Balance
Balancing total energy entering a boiler against
the energy that leaves the boiler in different forms
Heat in Steam
BOILER
Heat loss due to dry flue gas
Heat loss due to steam in fuel gas
Heat loss due to moisture in fuel
Heat loss due to unburnts in residue
Heat loss due to moisture in air
Heat loss due to radiation & other
unaccounted loss
%
%
%
%
2%
%
%
100.0 %
Fuel
60. Performance of a Boiler
Heat Balance
Goal: improve energy efficiency by reducing avoidable losses
Avoidable losses include:
- Stack gas losses (excess air, stack gas
temperature)
- Losses by unburnt fuel
- Blow down losses
- Condensate losses
- Convection and radiation
61. Performance of a Boiler
Boiler Efficiency
Thermal efficiency: % of (heat) energy input that is
effectively useful in the generated steam
BOILER EFFICENCY
CALCULATION
1) DIRECT METHOD: 2) INDIRECT METHOD:
The efficiency is the
different between losses
and energy input
The energy gain of the
working fluid (water and steam)
is compared with the energy
content of the boiler fuel.
62. Performance of a Boiler
hg -the enthalpy of saturated steam in kcal/kg of steam
hf -the enthalpy of feed water in kcal/kg of water
Boiler Efficiency: Direct Method
Boiler efficiency () =
Heat Input
Heat Output
x 100 Q x (hg – hf)
Q x GCV
x 100=
Parameters to be monitored:
- Quantity of steam generated per hour (Q) in kg/hr
- Quantity of fuel used per hour (q) in kg/hr
- The working pressure (in kg/cm2(g)) and superheat temperature
(oC), if any
- The temperature of feed water (oC)
- Type of fuel and gross calorific value of the fuel (GCV) in kcal/kg of
fuel
63. Performance of a Boiler
Advantages
• Quick evaluation
• Few parameters for computation
• Few monitoring instruments
• Easy to compare evaporation ratios with
benchmark figures
Disadvantages
• No explanation of low efficiency
• Various losses not calculated
Boiler Efficiency: Direct Method
64. Performance of a Boiler
Efficiency of boiler () = 100 – (i+ii+iii+iv+v+vi+vii)
Boiler Efficiency: Indirect Method
Principle losses:
i) Dry flue gas
ii) Evaporation of water formed due to H2 in fuel
iii) Evaporation of moisture in fuel
iv) Moisture present in combustion air
v) Unburnt fuel in fly ash
vi) Unburnt fuel in bottom ash
vii) Radiation and other unaccounted losses
65. Performance of a Boiler
Boiler Efficiency: Indirect Method
Required calculation data
• Ultimate analysis of fuel (H2, O2, S, C, moisture
content, ash content)
• % oxygen or CO2 in the flue gas
• Fuel gas temperature in ◦C (Tf)
• Ambient temperature in ◦C (Ta) and humidity of air in
kg/kg of dry air
• GCV of fuel in kcal/kg
• % combustible in ash (in case of solid fuels)
• GCV of ash in kcal/kg (in case of solid fuels)
66. Performance of a Boiler
Boiler Efficiency: Indirect Method
Advantages
• Complete mass and energy balance for each
individual stream
• Makes it easier to identify options to improve
boiler efficiency
Disadvantages
• Time consuming
• Requires lab facilities for analysis
67. Performance of a Boiler
• Controls ‘total dissolved solids’ (TDS) in the
water that is boiled
• Blows off water and replaces it with feed water
• Conductivity measured as indication of TDS
levels
• Calculation of quantity blow down required:
2. Boiler Blow Down
Blow down (%) =
Feed water TDS x % Make up water
Maximum Permissible TDS in Boiler water
68. Performance of a Boiler
Two types of blow down
• Intermittent
• Manually operated valve reduces TDS
• Large short-term increases in feed water
• Substantial heat loss
• Continuous
• Ensures constant TDS and steam purity
• Heat lost can be recovered
• Common in high-pressure boilers
Boiler Blow Down
69. Performance of a Boiler
Benefits
• Lower pretreatment costs
• Less make-up water consumption
• Reduced maintenance downtime
• Increased boiler life
• Lower consumption of treatment
chemicals
Boiler Blow Down
70. Performance of a Boiler
• Quality of steam depend on water
treatment to control
• Steam purity
• Deposits
• Corrosion
• Efficient heat transfer only if boiler
water is free from deposit-forming
solids
3. Boiler Feed Water Treatment
71. Performance of a Boiler
Deposit control
• To avoid efficiency losses and
reduced heat transfer
• Hardness salts of calcium and
magnesium
• Alkaline hardness: removed by boiling
• Non-alkaline: difficult to remove
• Silica forms hard silica scales
Boiler Feed Water Treatment
72. Performance of a Boiler
Internal water treatment
• Chemicals added to boiler to prevent scale
• Different chemicals for different water types
• Conditions:
• Feed water is low in hardness salts
• Low pressure, high TDS content is tolerated
• Small water quantities treated
• Internal treatment alone not recommended
Boiler Feed Water Treatment
73. Performance of a Boiler
External water treatment:
• Removal of suspended/dissolved solids and
dissolved gases
• Pre-treatment: sedimentation and settling
• First treatment stage: removal of salts
• Processes
a) Ion exchange
b) Demineralization
c) De-aeration
d) Reverse osmoses
Boiler Feed Water Treatment
74. Performance of a Boiler
a) Ion-exchange process (softener plant)
• Water passes through bed of natural zeolite of
synthetic resin to remove hardness
• Base exchange: calcium (Ca) and magnesium (Mg)
replaced with sodium (Na) ions
• Does not reduce TDS, blow down quantity and
alkalinity
b) Demineralization
• Complete removal of salts
• Cations in raw water replaced with hydrogen ions
External Water Treatment
75. Performance of a Boiler
c) De-aeration
• Dissolved corrosive gases (O2, CO2)
expelled by preheating the feed water
• Two types:
• Mechanical de-aeration: used prior to addition
of chemical oxygen scavangers
• Chemical de-aeration: removes trace oxygen
External Water Treatment
76. Performance of a Boiler
External Water Treatment
Stea
m
Storage
Section
De-aerated
Boiler Feed
Water
Scrubber
Section
(Trays)
Boiler Feed
Water
Vent
Spray
Nozzles
( National Productivity Council)
Mechanical
de-aeration
• O2 and CO2 removed by
heating feed water
• Economical treatment
process
• Vacuum type can reduce
O2 to 0.02 mg/l
• Pressure type can
reduce O2 to 0.005 mg/l
77. Performance of a Boiler
External Water Treatment
Chemical de-aeration
• Removal of trace oxygen with scavenger
• Sodium sulphite:
• Reacts with oxygen: sodium sulphate
• Increases TDS: increased blow down
• Hydrazine
• Reacts with oxygen: nitrogen + water
• Does not increase TDS: used in high pressure
boilers
78. Performance of a Boiler
d) Reverse osmosis
• Osmosis
• Solutions of differing concentrations
• Separated by a semi-permeable membrane
• Water moves to the higher concentration
• Reversed osmosis
• Higher concentrated liquid pressurized
• Water moves in reversed direction
External Water Treatment
79. Performance of a Boiler
d) Reverse osmosis
External water treatment
More
Concentrated
Solution
Fresh Water
Water Flow
Semi Permeable Membrane
Feed Water
Concentrate
Flow
Pressure
81. 1. Stack temperature control
2. Feed water preheating using economizers
3. Combustion air pre-heating
4. Incomplete combustion minimization
5. Excess air control
6. Avoid radiation and convection heat loss
7. Automatic blow down control
8. Reduction of scaling and soot losses
9. Reduction of boiler steam pressure
10. Variable speed control
11. Controlling boiler loading
12. Proper boiler scheduling
13. Boiler replacement
Energy Efficiency Opportunities
82. 1. Stack Temperature Control
• Keep as low as possible
• If >200°C then recover waste heat
Energy Efficiency Opportunities
2. Feed Water Preheating
Economizers
• Potential to recover heat from 200 – 300 oC flue
gases leaving a modern 3-pass shell boiler
3. Combustion Air Preheating
• If combustion air raised by 20°C = 1% improve
thermal efficiency
83. 4. Minimize Incomplete Combustion
• Symptoms:
• Smoke, high CO levels in exit flue gas
• Causes:
• Air shortage, fuel surplus, poor fuel distribution
• Poor mixing of fuel and air
• Oil-fired boiler:
• Improper viscosity, worn tops, cabonization on
dips, deterioration of diffusers or spinner plates
• Coal-fired boiler: non-uniform coal size
Energy Efficiency Opportunities
84. 84
Energy Efficiency Opportunities
5. Excess Air Control
• Excess air required for complete combustion
• Optimum excess air levels varies
• 1% excess air reduction = 0.6% efficiency rise
• Portable or continuous oxygen analyzers
Fuel Kg air req./kg fuel %CO2 in flue gas in practice
Solid Fuels
Bagasse
Coal (bituminous)
Lignite
Paddy Husk
Wood
3.3
10.7
8.5
4.5
5.7
10-12
10-13
9 -13
14-15
11.13
Liquid Fuels
Furnace Oil
LSHS
13.8
14.1
9-14
9-14
85. Energy Efficiency Opportunities
7. Automatic Blow Down Control
6. Radiation and Convection Heat
Loss Minimization
• Fixed heat loss from boiler shell, regardless of
boiler output
• Repairing insulation can reduce loss
• Sense and respond to boiler water conductivity
and pH
86. Energy Efficiency Opportunities
9. Reduced Boiler Steam Pressure
8. Scaling and Soot Loss Reduction
• Every 22oC increase in stack temperature = 1%
efficiency loss
• 3 mm of soot = 2.5% fuel increase
• Lower steam pressure
= lower saturated steam temperature
= lower flue gas temperature
• Steam generation pressure dictated by process
87. Energy Efficiency Opportunities
11. Control Boiler Loading
10. Variable Speed Control for Fans,
Blowers and Pumps
• Suited for fans, blowers, pumps
• Should be considered if boiler loads are
variable
• Maximum boiler efficiency: 65-85% of rated load
• Significant efficiency loss: < 25% of rated load
88. Energy Efficiency Opportunities
13. Boiler Replacement
12. Proper Boiler Scheduling
• Optimum efficiency: 65-85% of full load
• Few boilers at high loads is more efficient than
large number at low loads
Financially attractive if existing boiler is
• Old and inefficient
• Not capable of firing cheaper substitution fuel
• Over or under-sized for present requirements
• Not designed for ideal loading conditions