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.
Circulating fluidized bed boiler (cfb boiler) how does it work and its principlePichai Chaibamrung
This document provides an overview of circulating fluidized bed boilers. It begins with biographical information about the author Pichai Chaibamrung, followed by an outline of the content to be covered. The content sections include introductions to circulating fluidized bed design, hydrodynamics, combustion, heat transfer, and cyclone separators. Key points are made about fluidization regimes, characteristics of fast fluidized beds, stages of combustion, and factors impacting combustion efficiency.
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.
This document discusses three case studies related to circulating fluidized bed combustion (CFBC) boilers:
1) A case study of a CFBC boiler co-firing rice husk and coal that developed cracks in the cyclone outlet cone.
2) The importance of loop seal air nozzle arrangement in transferring ash particles between the cyclone and furnace and preventing gas bypass.
3) A case study of frequent failures of panel superheater tubes in a CFBC boiler due to insufficient anchoring of refractory bricks and erosion of tubes from the bottom. Modifications to the anchoring arrangement and use of a phosphate-bonded refractory were recommended.
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.
This document provides information on fired heaters, including methods of heat transfer, combustion, types of fired heaters, furnace parts, problems that can occur, and introduces several heaters at a refinery. It discusses the three main methods of heat transfer as conduction, convection, and radiation. Fired heaters use combustion of fuel to generate heat that is transferred to process fluids through tubes. Box and cylindrical designs are described. Key furnace parts and issues like overfiring, vibration, and inefficiency are outlined. Example heaters at the refinery include crude, vacuum, visbreaker, and hydrotreating unit heaters.
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.
Thermax Limited is an Indian company established in 1966 that provides sustainable energy and environmental solutions. It offers integrated solutions for heating, cooling, power, water, and air pollution control. The document focuses on Thermax's internally circulating fluidized bed circulating boiler (IR-CFBC) technology. The IR-CFBC uses a unique two-stage particle separation system and U-beam impact separators to efficiently separate solids from flue gas. This compact design results in lower maintenance costs compared to conventional circulating fluidized bed boilers. The IR-CFBC also has advantages like high combustion efficiency, low emissions, and improved performance during variable and low loads.
Circulating fluidized bed boiler (cfb boiler) how does it work and its principlePichai Chaibamrung
This document provides an overview of circulating fluidized bed boilers. It begins with biographical information about the author Pichai Chaibamrung, followed by an outline of the content to be covered. The content sections include introductions to circulating fluidized bed design, hydrodynamics, combustion, heat transfer, and cyclone separators. Key points are made about fluidization regimes, characteristics of fast fluidized beds, stages of combustion, and factors impacting combustion efficiency.
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.
This document discusses three case studies related to circulating fluidized bed combustion (CFBC) boilers:
1) A case study of a CFBC boiler co-firing rice husk and coal that developed cracks in the cyclone outlet cone.
2) The importance of loop seal air nozzle arrangement in transferring ash particles between the cyclone and furnace and preventing gas bypass.
3) A case study of frequent failures of panel superheater tubes in a CFBC boiler due to insufficient anchoring of refractory bricks and erosion of tubes from the bottom. Modifications to the anchoring arrangement and use of a phosphate-bonded refractory were recommended.
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.
This document provides information on fired heaters, including methods of heat transfer, combustion, types of fired heaters, furnace parts, problems that can occur, and introduces several heaters at a refinery. It discusses the three main methods of heat transfer as conduction, convection, and radiation. Fired heaters use combustion of fuel to generate heat that is transferred to process fluids through tubes. Box and cylindrical designs are described. Key furnace parts and issues like overfiring, vibration, and inefficiency are outlined. Example heaters at the refinery include crude, vacuum, visbreaker, and hydrotreating unit heaters.
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.
Thermax Limited is an Indian company established in 1966 that provides sustainable energy and environmental solutions. It offers integrated solutions for heating, cooling, power, water, and air pollution control. The document focuses on Thermax's internally circulating fluidized bed circulating boiler (IR-CFBC) technology. The IR-CFBC uses a unique two-stage particle separation system and U-beam impact separators to efficiently separate solids from flue gas. This compact design results in lower maintenance costs compared to conventional circulating fluidized bed boilers. The IR-CFBC also has advantages like high combustion efficiency, low emissions, and improved performance during variable and low loads.
The document discusses a student project on thermal power plants. It includes:
1) An introduction of the students and professor overseeing the project.
2) The objectives of the project which are to study how power is generated in thermal plants, the components like boilers and causes of boiler tube failures.
3) An outline of topics to be covered like the power generation principle, boilers, failures and case studies.
The presentation is for the engineers of HIRA POWER PLANT,. The complete calculations for calculation of boiler efficiency are described in the presentation
The presentation details about the Boiler Operation specifically while lightup of boiler and loading of boiler. the course participants discuss in details about the operations carried in their respective power stations
Hello,
I am trying to explain about Steam Generator (Boiler) in this session, due to length of said presentation, I am deciding to divide it in three parts.
Part 1 cover the “Introduction & Types of Steam Generator”
Part 2 cover about the “Parts of Steam Generator and Its Accessories & Auxiliaries” and
Part 3 cover the “Efficiency & Performance”
The document discusses Thermax Limited's internal recirculation circulating fluidized bed (IR-CFB) boiler technology. Some key benefits of IR-CFB boilers include higher separation efficiency across smaller particle sizes, uniform furnace temperatures, thin refractory, and lower operating and maintenance costs compared to other CFB designs. IR-CFB boilers also offer benefits such as high heat transfer rates, extended turndown ratios without auxiliary fuels, low auxiliary power needs, and fast shutdown times. The technology is supported by the operational experience of multiple installed IR-CFB boilers.
This document discusses various operational aspects and emergencies that can occur in an atmospheric fluidized bed combustion (AFBC) boiler. It outlines important parameters to monitor such as bed height, air pressures, temperatures, and fuel sizes. It then describes several emergency conditions that can happen including low or high drum levels, high furnace pressure, high or low bed/furnace temperatures, tube failures, and flame failures. For each condition, it discusses potential causes, effects on the boiler, and recommended actions to address the problem.
1. Supercritical boilers operate above the critical pressure of water (221 bar), where there is no distinction between water and steam.
2. Operating above the critical pressure provides benefits like higher cycle efficiency, lower fuel consumption and emissions, and improved load change flexibility compared to subcritical boilers.
3. The key difference between subcritical and supercritical boilers is that supercritical boilers are drumless, with evaporation occurring in a single pass and flow induced by the feed pump rather than natural circulation.
Ntpc (national thermal power corporation) sipat boiler haxxo24 i~ihaxxo24
The document discusses key points about subcritical and supercritical boiler design, operation, and control including:
- Differences between subcritical and supercritical boiler technologies
- Design parameters like steam pressure and temperature, air flow rates, and coal requirements
- Chemical treatment, feedwater, and boiler control systems
- Startup procedures including boiler filling and transitioning between wet and dry modes
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
This document provides a guide to furnace sootblowing. It begins with an introduction that notes each boiler design is unique based on the engineer's goals and compromises. It then presents a simplified model of a furnace to demonstrate sootblowing concepts. The model shows heat distribution, temperatures, spray flows, and slag accumulation. Next, it explains that 33% of heat goes to the waterwalls, 31% to the superheater, 18% to the reheater, and 17% to the economizer at 100% load. Heat distribution varies by pressure, requiring more heat to the waterwalls at lower pressures. The document then covers sootblower types and control systems before discussing plant condition changes.
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.
Heaters are used in refineries to raise the temperature of process fluids. There are different types of heaters classified by design and firing method. Key components include tubes, burners, and sections for convection and radiation. Proper draft, excess air, and complete combustion are important for safe and efficient operation. Regular checks help ensure heaters are functioning properly and identify any issues.
This document provides information on four types of cement kiln coolers: planetary coolers, rotary coolers, grate coolers, and cross-bar coolers. It focuses on describing the design and operation of planetary coolers in detail. Planetary coolers consist of multiple rotating cooler tubes attached directly to the kiln that cascade clinker through counterflowing air. They provide good heat transfer efficiency but have higher clinker exit temperatures than grate coolers. The document also provides typical heat loss figures for a planetary cooler.
The document outlines the steps to safely shut down a 210 MW power generation unit for overhaul and maintenance. It involves gradually reducing boiler steam parameters and turbine load over several steps by cutting mills and heaters, before finally tripping the turbine. Key steps include maintaining temperature differences, ensuring availability of emergency equipment, monitoring parameters, and opening drains. The shutdown is completed by venting the boiler drum and stopping auxiliary systems once drum pressure is reduced.
Soot Blowing Optimization- Field ExperiencePooja Agarwal
The document discusses soot blower optimization strategies implemented at Jindal Power Limited coal-fired power plants. Previously, all 56 furnace wall soot blowers were operated once every 8 hours, consuming substantial steam. Through a study, JPL found that operating soot blowers in certain areas and sequences had little effect on boiler parameters. This allowed reducing operations to only blowing 14 blowers once daily and 28 blowers every other day, saving over 1,300 tons of steam annually. Financial savings from reduced steam and coal usage were estimated at over 4 lakh rupees annually. The optimized strategy improved boiler performance and heat rate while reducing emissions and maintenance costs.
This document discusses the calculation of heat rate and turbine cylinder efficiency for a 210 MW KWU turbine cycle. It describes the enthalpy method used to calculate heat rate, which involves measuring steam and flow parameters at various points and using steam tables to determine enthalpy values. The calculation is done in four parts: measurements, enthalpy calculations, determining hot reheat flow, and the final heat rate calculation. Turbine cylinder efficiency is also calculated using enthalpy drop methods by determining actual and theoretical enthalpy changes across the high pressure turbine. Standard methods and typical heat rates for different capacity turbines are also listed.
Unit-1-Coal Based Thermal Power Plants.pptdharma raja`
The document discusses coal-based thermal power plants and their components. It describes the Rankine cycle used in steam turbines and improvements like reheating and regeneration. Modern coal power plants use once-through or fluidized bed combustion boilers and supercritical conditions. Steam is expanded through turbines into a condenser. Subsystems include coal and ash handling, draught systems, and feedwater treatment. Binary cycles are also discussed as a way to improve efficiency by using a secondary working fluid like mercury.
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 a student project on thermal power plants. It includes:
1) An introduction of the students and professor overseeing the project.
2) The objectives of the project which are to study how power is generated in thermal plants, the components like boilers and causes of boiler tube failures.
3) An outline of topics to be covered like the power generation principle, boilers, failures and case studies.
The presentation is for the engineers of HIRA POWER PLANT,. The complete calculations for calculation of boiler efficiency are described in the presentation
The presentation details about the Boiler Operation specifically while lightup of boiler and loading of boiler. the course participants discuss in details about the operations carried in their respective power stations
Hello,
I am trying to explain about Steam Generator (Boiler) in this session, due to length of said presentation, I am deciding to divide it in three parts.
Part 1 cover the “Introduction & Types of Steam Generator”
Part 2 cover about the “Parts of Steam Generator and Its Accessories & Auxiliaries” and
Part 3 cover the “Efficiency & Performance”
The document discusses Thermax Limited's internal recirculation circulating fluidized bed (IR-CFB) boiler technology. Some key benefits of IR-CFB boilers include higher separation efficiency across smaller particle sizes, uniform furnace temperatures, thin refractory, and lower operating and maintenance costs compared to other CFB designs. IR-CFB boilers also offer benefits such as high heat transfer rates, extended turndown ratios without auxiliary fuels, low auxiliary power needs, and fast shutdown times. The technology is supported by the operational experience of multiple installed IR-CFB boilers.
This document discusses various operational aspects and emergencies that can occur in an atmospheric fluidized bed combustion (AFBC) boiler. It outlines important parameters to monitor such as bed height, air pressures, temperatures, and fuel sizes. It then describes several emergency conditions that can happen including low or high drum levels, high furnace pressure, high or low bed/furnace temperatures, tube failures, and flame failures. For each condition, it discusses potential causes, effects on the boiler, and recommended actions to address the problem.
1. Supercritical boilers operate above the critical pressure of water (221 bar), where there is no distinction between water and steam.
2. Operating above the critical pressure provides benefits like higher cycle efficiency, lower fuel consumption and emissions, and improved load change flexibility compared to subcritical boilers.
3. The key difference between subcritical and supercritical boilers is that supercritical boilers are drumless, with evaporation occurring in a single pass and flow induced by the feed pump rather than natural circulation.
Ntpc (national thermal power corporation) sipat boiler haxxo24 i~ihaxxo24
The document discusses key points about subcritical and supercritical boiler design, operation, and control including:
- Differences between subcritical and supercritical boiler technologies
- Design parameters like steam pressure and temperature, air flow rates, and coal requirements
- Chemical treatment, feedwater, and boiler control systems
- Startup procedures including boiler filling and transitioning between wet and dry modes
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
This document provides a guide to furnace sootblowing. It begins with an introduction that notes each boiler design is unique based on the engineer's goals and compromises. It then presents a simplified model of a furnace to demonstrate sootblowing concepts. The model shows heat distribution, temperatures, spray flows, and slag accumulation. Next, it explains that 33% of heat goes to the waterwalls, 31% to the superheater, 18% to the reheater, and 17% to the economizer at 100% load. Heat distribution varies by pressure, requiring more heat to the waterwalls at lower pressures. The document then covers sootblower types and control systems before discussing plant condition changes.
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.
Heaters are used in refineries to raise the temperature of process fluids. There are different types of heaters classified by design and firing method. Key components include tubes, burners, and sections for convection and radiation. Proper draft, excess air, and complete combustion are important for safe and efficient operation. Regular checks help ensure heaters are functioning properly and identify any issues.
This document provides information on four types of cement kiln coolers: planetary coolers, rotary coolers, grate coolers, and cross-bar coolers. It focuses on describing the design and operation of planetary coolers in detail. Planetary coolers consist of multiple rotating cooler tubes attached directly to the kiln that cascade clinker through counterflowing air. They provide good heat transfer efficiency but have higher clinker exit temperatures than grate coolers. The document also provides typical heat loss figures for a planetary cooler.
The document outlines the steps to safely shut down a 210 MW power generation unit for overhaul and maintenance. It involves gradually reducing boiler steam parameters and turbine load over several steps by cutting mills and heaters, before finally tripping the turbine. Key steps include maintaining temperature differences, ensuring availability of emergency equipment, monitoring parameters, and opening drains. The shutdown is completed by venting the boiler drum and stopping auxiliary systems once drum pressure is reduced.
Soot Blowing Optimization- Field ExperiencePooja Agarwal
The document discusses soot blower optimization strategies implemented at Jindal Power Limited coal-fired power plants. Previously, all 56 furnace wall soot blowers were operated once every 8 hours, consuming substantial steam. Through a study, JPL found that operating soot blowers in certain areas and sequences had little effect on boiler parameters. This allowed reducing operations to only blowing 14 blowers once daily and 28 blowers every other day, saving over 1,300 tons of steam annually. Financial savings from reduced steam and coal usage were estimated at over 4 lakh rupees annually. The optimized strategy improved boiler performance and heat rate while reducing emissions and maintenance costs.
This document discusses the calculation of heat rate and turbine cylinder efficiency for a 210 MW KWU turbine cycle. It describes the enthalpy method used to calculate heat rate, which involves measuring steam and flow parameters at various points and using steam tables to determine enthalpy values. The calculation is done in four parts: measurements, enthalpy calculations, determining hot reheat flow, and the final heat rate calculation. Turbine cylinder efficiency is also calculated using enthalpy drop methods by determining actual and theoretical enthalpy changes across the high pressure turbine. Standard methods and typical heat rates for different capacity turbines are also listed.
Unit-1-Coal Based Thermal Power Plants.pptdharma raja`
The document discusses coal-based thermal power plants and their components. It describes the Rankine cycle used in steam turbines and improvements like reheating and regeneration. Modern coal power plants use once-through or fluidized bed combustion boilers and supercritical conditions. Steam is expanded through turbines into a condenser. Subsystems include coal and ash handling, draught systems, and feedwater treatment. Binary cycles are also discussed as a way to improve efficiency by using a secondary working fluid like mercury.
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.
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.
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 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.
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.
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.
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.
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.
1. The document provides answers to questions about cement rotary kilns, including the maximum safe shell temperature, differences between hot spots and red spots, factors affecting when a red spot would force a kiln to stop, oxygen enrichment technology, classifying precalciners, factors affecting the number of cyclone stages, the significance of liquid phase in clinker formation, and reasons for rings build-up inside kilns.
2. It discusses technical details and provides definitions, diagrams, and tables to support the explanations.
3. Common causes of rings build-up include sulfur rings from excess sulfur, spurrite rings from high carbon dioxide, and alkali rings from low-melting potassium salts.
1) The document discusses questions and answers related to cement rotary kilns and precalciners. It provides information on maximum safe shell temperatures, definitions of hot spots and red spots, factors to consider regarding kiln stoppage due to red spots, oxygen enrichment technology, and classifications of precalciners.
2) Oxygen enrichment technology involves injecting oxygen into kiln or precalciner burners to improve energy efficiency and production capacity. It allows use of lower quality fuels and reduces CO2 emissions.
3) Precalciners are classified based on where combustion takes place - in a mixture of gases, pure air, or a combination. Equipment suppliers like FLSmidth classify precalciners slightly differently into in
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.
The document provides an overview of a fluidized catalytic cracking unit (FCCU) at an Indian oil corporation. It describes the FCCU's feedstocks as heavy vacuum gas oil and once-through hydrogen cracker unit bottom oil. The main products are dry gas, LPG, gasoline, heavy naphtha, light cycle oil, and coke. It outlines the reactor, regenerator, fractionator, and gas concentration sections of the FCCU and discusses key operating parameters like temperatures, pressures, and catalyst/oil ratio.
This document provides an overview of high pressure boilers and fluidized bed combustion boilers. It defines boilers according to the Indian Boiler Regulation Act and classifies boilers based on various factors such as pressure, circulation method, orientation, and firing method. Examples of high pressure boilers like Lamont, Benson, and Velox are described along with their features. Fluidized bed combustion boilers are classified and their arrangements and control systems are explained. Maintenance procedures for high pressure and FBC boilers are also outlined.
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.
Development of an innovative 3 stage steady bed gasifier slidesravi8492
The document describes a new 3-stage gasification scheme for municipal solid waste and biomass. The scheme consists of pyrolysis, combustion, and gasification stages, and can operate normally or in reverse mode by adjusting air blowers. It produces synthesis gas free of tars and dioxins with 30% electrical efficiency. A SWOT analysis found strengths include adequate replacement of fossil fuels while weaknesses include unproven reliability and moderate costs.
This document provides information about coal-based thermal power plants, including their layout and components. It discusses the Rankine cycle and improvements like reheating and regeneration. It also describes the coal handling system, from delivery to combustion in the furnace. The working of steam turbines is explained. Further, it covers components like the boiler, pulverizers, burners, dust collectors, draft systems, cooling towers, and water treatment systems. Cogeneration systems are also discussed.
The document provides information on different types of boiler systems and their components. It discusses 7 types of boilers - fire tube boiler, water tube boiler, packaged boiler, stoker fired boiler, pulverized fuel boiler, waste heat boiler, and fluidized bed boiler. It provides details on the mechanisms, advantages and disadvantages of each type. It specifically focuses on describing the mechanisms of fluidized bed combustion and the 3 types of fluidized bed combustion systems - atmospheric fluidized bed combustion, pressurized fluidized bed combustion, and circulating fluidized bed combustion.
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.
Similar to Cfb boiler basic design, operation and maintenance (20)
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Physiology and chemistry of skin and pigmentation, hairs, scalp, lips and nail, Cleansing cream, Lotions, Face powders, Face packs, Lipsticks, Bath products, soaps and baby product,
Preparation and standardization of the following : Tonic, Bleaches, Dentifrices and Mouth washes & Tooth Pastes, Cosmetics for Nails.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
-------------------------------------------------------------------------------
Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
-------------------------------------------------------------------------------
For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
Assessment and Planning in Educational technology.pptxKavitha Krishnan
In an education system, it is understood that assessment is only for the students, but on the other hand, the Assessment of teachers is also an important aspect of the education system that ensures teachers are providing high-quality instruction to students. The assessment process can be used to provide feedback and support for professional development, to inform decisions about teacher retention or promotion, or to evaluate teacher effectiveness for accountability purposes.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
2. 2
Content Day1
1. Introduction to CFB
2. Hydrodynamic of CFB
3. Combustion in CFB
4. Heat Transfer in CFB
5. Basic design of CFB
6. Operation
7. Maintenance
8. Basic Boiler Safety
9. Basic CFB control
3. 3
Objective
— To understand the typical arrangement in CFB
— To understand the basic hydrodynamic of CFB
— To understand the basic combustion in CFB
— To understand the basic heat transfer in CFB
— To understand basic design of CFB
— To understand theory of cyclone separator
Know Principle Solve Everything
4. 4
1. Introduction to CFB
1.1 Development of CFB
1.2 Typical equipment of CFB
1.3 Advantage of CFB
5. 5
1.1 Development of CFB
— 1921, Fritz Winkler, Germany, Coal Gasification
— 1938, Waren Lewis and Edwin Gilliland, USA, Fluid Catalytic Cracking,
Fast Fluidized Bed
— 1960, Douglas Elliott, England, Coal Combustion, BFB
— 1960s, Ahlstrom Group, Finland, First commercial CFB boiler, 15
MWth, Peat
7. 7
1.2 Typical Component of CFB Boiler
Wind box and grid nozzle
primary air is fed into wind box.
Air is equally distributed on
furnace cross section by passing
through the grid nozzle. This will
help mixing of air and fuel for
completed combustion
8. 8
1.2 Typical Component of CFB Boiler
Bottom ash drain
coarse size of ash that is not
take away from furnace by
fluidizing air will be drain
at bottom ash drain port
locating on grid nozzle
floor by gravity.
bottom ash will be cooled
and conveyed to silo by
cooling conveyor.
9. 9
1.2 Typical Component of CFB Boiler
HP Blower
supply high pressure air to
fluidize bed material in loop
seal so that it can overflow to
furnace
Rotameter
Supplying of HP
blower to loop seal
10. 10
1.2 Typical Component of CFB Boiler
Cyclone separator
located after furnace exit and
before convective part.
use to provide circulation by
trapping coarse particle back to
the furnace
Fluidized boiler without this
would be BFB not CFB
11. 11
1.2 Typical Component of CFB Boiler
Evaporative or Superheat Wing Wall
located on upper zone of furnace
it can be both of evaporative or SH
panel
lower portion covered by erosion
resistant materials
12. 12
1.2 Typical Component of CFB Boiler
Fuel Feeding system
solid fuel is fed into the lower
zone of furnace through the
screw conveyor cooling with
combustion air. Number of
feeding port depend on the
size of boiler
13. 13
1.2 Typical Component of CFB Boiler
Refractory
refractory is used to protect
the pressure part from
serious erosion zone such as
lower bed, cyclone separator
14. 14
1.2 Typical Component of CFB Boiler
Solid recycle system (Loop seal)
loop seal is located between
dip leg of separator and
furnace. Its design physical is
similar to furnace which have
air box and nozzle to
distribute air. Distributed air
from HP blower initiate
fluidization. Solid behave like
a fluid then over flow back to
the furnace.
15. 15
1.2 Typical Component of CFB Boiler
Kick out
kick out is referred to
interface zone between
the end of lower zone
refractory and water tube.
It is design to protect the
erosion by by-passing the
interface from falling
down bed materials
16. 16
1.2 Typical Component of CFB Boiler
Lime stone and sand system
lime stone is pneumatically feed or gravitational feed into
the furnace slightly above fuel feed port. the objective is to
reduce SOx emission.
Sand is normally fed by gravitation from silo in order to
maintain bed pressure. Its flow control by speed of rotary
screw.
19. 19
1.3 Advantage of CFB Boiler
— High Combustion Efficiency
- Good solid mixing
- Low unburned loss by cyclone, fly ash recirculation
- Long combustion zone
— In situ sulfur removal
— Low nitrogen oxide emission
20. 20
2. Hydrodynamic in CFB
2.1 Regimes of Fluidization
2.2 Fast Fluidized Bed
2.3 Hydrodynamic Regimes in CFB
2.4 Hydrodynamic Structure of Fast Beds
21. 21
2.1 Regimes of Fluidization
— Fluidization is defined as the operation through which fine
solid are transformed into a fluid like state through
contact with a gas or liquid.
24. 24
2.1 Regimes of Fluidization
— Comparison of Principal Gas-Solid Contacting Processes
25. 25
2.1 Regimes of Fluidization
— Packed Bed
The pressure drop per unit height of a packed beds of a uniformly size
particles is correlated as (Ergun,1952)
Where U is gas flow rate per unit cross section of the bed called
Superficial Gas Velocity
26. 26
2.1 Regimes of Fluidization
— Bubbling Fluidization Beds
Minimum fluidization velocity is velocity where the fluid
drag is equal to a particle’s weight less its buoyancy.
27. 27
2.1 Regimes of Fluidization
— Bubbling Fluidization Beds
For B and D particle, the bubble is started when superficial
gas is higher than minimum fluidization velocity
But for group A particle the bubble is started when
superficial velocity is higher than minimum bubbling
velocity
28. 28
2.1 Regimes of Fluidization
— Turbulent Beds
when the superficial is continually increased through a
bubbling fluidization bed, the bed start expanding, then
the new regime called turbulent bed is started.
30. 30
2.1 Regimes of Fluidization
— Terminal Velocity
Terminal velocity is the particle velocity when the
forces acting on particle is equilibrium
31. 31
2.1 Regimes of Fluidization
— Freeboard and Furnace Height
- considered for design heating-surface area
- considered for design furnace height
- to minimize unburned carbon in bubbling
bed
- the freeboard heights should be exceed or
closed to the transport disengaging heights
33. 33
2.2 Fast Fluidization
— Characteristics of Fast Beds
- non-uniform suspension of slender particle agglomerates or clusters moving
up and down in a dilute
- excellent mixing are major characteristic
- low feed rate, particles are uniformly dispersed in gas stream
- high feed rate, particles enter the wake of the other, fluid drag on the leading
particle decrease, fall under the gravity until it drops on to trailing particle
34. 34
2.3 Hydrodynamic regimes in a CFB
Lower Furnace below SA:
Turbulent or bubbling
fluidized bed
Furnace Upper SA:
Fast Fluidized Bed
Cyclone Separator :
Swirl Flow
Return leg and lift leg :
Pack bed and Bubbling Bed
Back Pass:
Pneumatic Transport
35. 35
2.4 Hydrodynamic Structure of Fast Beds
— Axial Voidage Profile
Bed Density Profile of 135 MWe CFB Boiler (Zhang et al., 2005)
Secondary air is fed
40. 40
2.4 Hydrodynamic Structure of Fast Beds
— Particle Distribution Profile in Fast Fluidized Bed
Effect of SA injection on particle
distribution by M.Koksal and
F.Hamdullahpur (2004). The
experimental CFB is pilot scale CFB.
There are three orientations of SA
injection; radial, tangential, and mixed
41. 41
2.4 Hydrodynamic Structure of Fast Beds
— Particle Distribution Profile in Fast Fluidized Bed
No SA, the suspension
density is proportional
l to solid circulation rate
With SA 20% of PA,
the solid particle is hold up
when compare to no SA
Increasing SA to 40%
does not significant on
suspension density above
SA injection point
but the low zone is
denser than low SA ratio
Increasing solid circulation
rate effect to both
lower and upper zone
of SA injection point
which both zone is
denser than low
solid circulation rate
42. 42
2.4 Hydrodynamic Structure of Fast Beds
— Effects of Circulation Rate on Voidage Profile
higher solid recirculation rate
43. 43
2.4 Hydrodynamic Structure of Fast Beds
— Effects of Circulation Rate on Voidage Profile
higher solid recirculation rate
Pressure drop across the L-valve is
proportional to solid recirculation rate
44. 44
2.4 Hydrodynamic Structure of Fast Beds
— Effect of Particle Size on Suspension Density Profile
- Fine particle - - > higher suspension density
- Higher suspension density - - > higher heat transfer
- Higher suspension density - - > lower bed temperature
45. 45
2.4 Hydrodynamic Structure of Fast Beds
— Core-Annulus Model
- the furnace may be spilt into two zones : core and
annulus
Core
- Velocity is above superficial velocity
- Solid move upward
Annulus
- Velocity is low to negative
- Solids move downward
core
annulus
47. 47
2.4 Hydrodynamic Structure of Fast Beds
— Core Annulus Model
- the up-and-down movement solids in the core and
annulus sets up an internal circulation
- the uniform bed temperature is a direct result of internal
circulation
48. 48
3. Combustion in CFB
3.1 Coal properties for CFB boiler
3.2 Stage of Combustion
3.3 Factor Affecting Combustion Efficiency
3.4 Combustion in CFB
3.5 Biomass Combustion
49. 49
3.1 Coal properties for CFB Boiler
Properties
- coarse size coal shall be crushed by coal crusher
- sizing is an importance parameter for CFB boiler improper size might
result in combustion loss
- normal size shall be < 8 mm
50. 50
3.2 Stage of Combustion
A particle of solid fuel is injected into an FB undergoes the
following sequence of events:
- Heating and drying
- Devolatilization and volatile combustion
- Swelling and primary fragmentation (for some types of coal)
- Combustion of char with secondary fragmentation and attrition
51. 51
3.2 Stages of Combustion
— Heating and Drying
- Combustible materials constitutes around 0.5-5.0% by
weight
of total solids in combustor
- Rate of heating 100 °C/sec – 1000 °C/sec
- Heat transfer to a fuel particle (Halder 1989)
52. 52
3.2 Stages of Combustion
Devolatilization and volatile combustion
- first steady release 500-600 C
- second release 800-1000C
- slowest species is CO (Keairns et al., 1984)
- 3 mm coal take 14 sec to devolatilze
at 850 C (Basu and Fraser, 1991)
53. 53
3.2 Stages of Combustion
— Char Combustion
2 step of char combustion
1. transportation of oxygen to carbon surface
2. Reaction of carbon with oxygen on the carbon surface
3 regimes of char combustion
- Regime I: mass transfer is higher than kinetic rate
- Regime II: mass transfer is comparable to kinetic rate
- Regime III: mass transfer is very slow compared to kinetic rate
54. 54
3.2 Stage of Combustion
— Communition Phenomena During Combustion
Volatile release cause the
particle swell
Volatile release in non-porous
particle cause the high
internal pressure result in
break a coal particle into
fragmentation
Char burn under regime I, II,
the pores increases in size à
weak bridge connection of
carbon until it can’t withstand
the hydrodynamic force. It will
fragment again call “
secondary fragmentation”
Attrition, Fine particles from
coarse particles through
mechanical contract like
abrasion with other particles
Char burn under regime I
which is mass transfer is
higher than kinetic trasfer.
The sudden collapse or other
type of second fragmentation
call percolative fragmentation
occurs
55. 55
3.3 Factor Affecting Combustion Efficiency
— Fuel Characteristics
the lower ratio of FC/VM result in higher combustion
efficiency (Makansi, 1990), (Yoshioka and Ikeda,1990),
(Oka, 2004) but the improper mixing could result in lower
combustion efficiency due to prompting escape of volatile
gas from furnace.
56. 56
3.3 Factor Affecting Combustion Efficiency
— Operating condition (Bed Temperature)
- higher combustion temperature --- > high combustion
efficiency
High combustion temperature result in high
oxidation reaction, then burn out time
decrease. So the combustion efficiency
increase.
Limit of Bed temp
-Sulfur capture
-Bed melting
-Water tube failure
57. 57
3.3 Factor Affecting Combustion Efficiency
— Fuel Characteristic (Particle size)
-The effect of this particle size is not clear
-Fine particle, low burn out time but the
probability to be dispersed from cyclone
the high
-Coarse size, need long time to burn out.
-Both increases and decreases are
possible when particle size decrease
58. 58
3.3 Factor Affecting Combustion Efficiency
— Operating condition (superficial velocity)
- high fluidizing velocity decrease combustion efficiency because
Increasing probability of small char particle be elutriated from
circulation loop
- low fluidizing velocity cause defluidization, hot spot and sintering
59. 59
3.3 Factor Affecting Combustion Efficiency
— Operating condition (excess air)
- combustion efficiency improve which excess air < 20%
Excess air >20% less
significant improve
combustion efficiency.
Combustion loss
decrease
significantly when
excess air < 20%.
60. 60
3.3 Factor Affecting Combustion Efficiency
Operating Condition
The highest loss of combustion result from elutriation of char particle
from circulation loop. Especially, low reactive coal size smaller than 1
mm it can not achieve complete combustion efficiency with out fly
ash recirculation system.
However, the significant efficiency improve is in range 0.0-2.0 fly ash
recirculation ratio.
61. 61
3.4 Combustion in CFB Boiler
— Lower Zone Properties
- This zone is fluidized by primary air constituting about
40-80% of total air.
- This zone receives fresh coal from coal feeder and
unburned coal from cyclone though return valve
- Oxygen deficient zone, lined with refractory to protect
corrosion
- Denser than upper zone
62. 62
3.4 Combustion in CFB Boiler
— Upper Zone Properties
- Secondary is added at interface between lower and upper
zone
- Oxygen-rich zone
- Most of char combustion occurs
- Char particle could make many trips around the furnace
before they are finally entrained out through the top of
furnace
63. 63
3.4 Combustion in CFB Boiler
— Cyclone Zone Properties
- Normally, the combustion is small when compare to in
furnace
- Some boiler may experience the strong combustion in
this zone which can be observe by rising temperature in
the cyclone exit and loop seal
64. 64
3.5 Biomass Combustion
— Fuel Characteristics
- high volatile content (60-80%)
- high alkali content à sintering, slagging, and fouling
- high chlorine content à corrosion
65. 65
3.5 Biomass Combustion
— Agglomeration
SiO2 melts at 1450 C
Eutectic Mixture melts at 874 C
Sintering tendency of fuel is indicated by the following
(Hulkkonen et al., 2003)
66. 66
3.5 Biomass Combustion
Options for Avoiding the Agglomeration Problem
- Use of additives
- china clay, dolomite, kaolin soil
- Preprocessing of fuels
- water leaching
- Use of alternative bed materials
- dolomite, magnesite, and alumina
- Reduction in bed temperature
68. 68
3.5 Biomass Combustion
— Fouling
- is sticky deposition of ash due to evaporation of alkali salt
- result in low heat transfer to tube
69. 69
3.5 Biomass Combustion
— Corrosion Potential in Biomass Firing
- hot corrosion
- chlorine reacts with alkali metal à from low
temperature melting alkali chlorides
- reduce heat transfer and causing high temperature
corrosion
70. 70
4. Heat Transfer in CFB
4.1 Gas to Particle Heat Transfer
4.2 Heat Transfer in CFB
71. 71
4.1 Gas to Particle Heat Transfer
— Mechanism of Heat Transfer
In a CFB boiler, fine solid particles
agglomerate and form clusters or
stand in a continuum of generally
up-flowing gas containing sparsely
dispersed solids. The continuum is
called the dispersed phase, while
the agglomerates are called the
cluster phase.
The heat transfer to furnace wall
occurs through conduction from
particle clusters, convection from
dispersed phase, and radiation
from both phase.
72. 72
4.1 Heat Transfer in CFB Boiler
— Effect of Suspension Density and particle size
Heat transfer coefficient is proportional to the square root of suspension density
73. 73
4.1 Heat Transfer in CFB Boiler
— Effect of Fluidization Velocity
No effect from fluidization velocity when leave the suspension density constant
78. 78
4.1 Heat Transfer in CFB Boiler
— Heat Flux on 300 MW CFB Boiler (Z. Man, et. al)
79. 79
4.1 Heat Transfer in CFB Boiler
— Heat transfer to the walls of commercial-size
Low suspension density low
heat transfer to the wall.
80. 80
4.1 Heat Transfer in CFB Boiler
— Circumferential Distribution of Heat Transfer Coefficient
81. 81
5 Design of CFB Boiler
— 5.1 Design and Required Data
— 5.2 Combustion Calculation
— 5.3 Heat and Mass Balance
— 5.4 Furnace Design
— 5.5 Cyclone Separator
82. 82
5.1 Design and Required Data
The design and required data normally will be specify by owner
or client. The basic design data and required data are;
Design Data :
- Fuel ultimate analysis - Weather condition
- Feed water quality - Feed water properties
Required Data :
- Main steam properties - Flue gas temperature
- Flue gas emission - Boiler efficiency
83. 83
5.2 Combustion Calculation
— Base on the design and required data the following data
can be calculated in this stage :
- Fuel flow rate - Combustion air flow rate
- Fan capacity - Fuel and ash handling capacity
- Sorbent flow rate
84. 84
5.3 Heat and Mass Balance
Fuel and
sorbent
Unburned in
bottom ash
Feed water
Combustion air
Main steam
Blow down
Flue gas
Moisture in fuel
and sorbent
Unburned in fly ash
Moisture in
combustion air
Radiation
Heat input
Heat output
85. 85
5.3 Heat and Mass Balance
— Mass Balance
Fuel and
sorbent
bottom ash
Solid Flue gas
Moisture in fuel
and sorbent
fly ash
Make up
bed material
bottom ash
Fuel and
sorbent
Make up
bed material
Solid in Flue gas
fly ash
Mass output
Mass input
86. 86
5.4 Furnace Design
— The furnace design include:
1. Furnace cross section
2. Furnace height
3. Furnace opening
1. Furnace cross section
Criteria
- moisture in fuel
- ash in fuel
- fluidization velocity
- SA penetration
- maintain fluidization in lower
zone at part load
89. 89
5.5 Cyclone Separator
— The centrifugal force on the particle entering the cyclone
is
— The drag force on the particle can be written as
— Under steady state drag force = centrifugal force
90. 90
5.5 Cyclone Separator
— Vr can be considered as index of cyclone efficiency, from
above equation the cyclone efficiency will increase for :
- Higher entry velocity
- Large size of solid
- Higher density of particle
- Small radius of cyclone
- low value of viscosity of gas
91. 91
5.5 Cyclone Separator
— The particle with a diameter larger than theoretical cut-
size of cyclone will be collected or trapped by cyclone
while the small size will be entrained or leave a cyclone
— Actual operation, the cut-off size diameter will be defined
as d50 that mean 50% of the particle which have a
diameter more than d50 will be collected or captured.
93. 93
Content
6.1 Before start
6.2 Grid pressure drop test
6.3 Cold Start
6.4 Normal Operation
6.5 Normal Shutdown
6.6 Hot Shutdown
6.7 Hot Restart
6.8 Malfunction and Emergency
94. 94
6.1 Before Start
— all maintenance work have been completely done
— All function test have been checked
— cooling water system is operating
— compressed air system is operating
— Make up water system
— Deaerator system
— Boiler feed water pump
— Condensate system
— Oil and gas system
— Drain and vent valves
— Air duct, flue gas duct system
95. 95
6.1 Before Start
— Blow down system
— Sand feeding system
— Lime stone feeding system
— Solid fuel system
— Ash drainage system
— Control and safety interlock system
96. 96
6.2 Grid Pressure Drop Test
— For check blockage of grid
nozzle
— Furnace set point = 0
— Test at every PA. load
— Compare to clean data or design
data
— Shall not exceed 10% from
design data
— Perform in cold condition
Pw
Pb
FI
Pf= 0
97. 97
6.3 Cold Start
Fill boiler
Boiler Interlock
Start up Burner
Feed Solid Fuel
Boiler Warm Up
Purge
Start Fan
Feed Bed Material
Raise to MCR
-100 mm normal level
ID,HP,SA,PA
Low level cut off
300 S
Tb 150-200 C
30-50 mbar, Tb 550-600 C
98. 98
Fill Boiler
-Close all water side drain valve
-Open all air vent valve at drum and
superheat
-Open start up vent valve 10-15%
-Slowly feed water to drum until level 1/3 of
sigh glass
100. 100
Boiler Interlock
Emergency stop in order
Furnace P. < Max (2/3)
ID. Fan running
HP Blower start
Drum level > min (2/3)
SA. Fan running
PA. Fan running
HP. Blower P. > min
PA. Flow to grid > min
Trip Solid Fuel
Flue gas T after Furnace < max
Trip Soot Blower
Trip Oil
Trip Sand
Trip Lime Stone
Trip Bottom Ash
101. 101
Purge
— To carry out combustible gases
— To assure all fuel are isolated
from furnace
— Before starting first burner for
cold start
— If bed temp < 600 C or OEM
recommend and no burner in
service
— Total air flow > 50%
— 300 sec for purging time
103. 103
Start up burner
— Help to heat up bed temp to allowable temperature for
feeding solid fuel
— Will be stopped if bed temp > 850 C
— Before starting, all interlock have to passed
— Main interlock
— Oil pressure > minimum
— Control air pressure > minimum
— Atomizing air pressure > minimum
105. 105
Drum and DA low level cut-off
— Test for safety
— During burner are operating
— Open drain until low level
— Signal feeding are not allow
— Steam drum low level = chance
to overheating of water tube
— DA low level = danger for BFWP
106. 106
Boiler warm up
— Gradually heating the boiler to reduce the effect of
thermal stress on pressure part, refractory and drum swell
— Increase bed temp 60-80 C/hr by adjusting SUB
— Control flue gas temperature <470 C until steam flow >
10% MCR
— Close vent valves at drum and SH when pressure > 2 bar
— Continue to increase firing rate according to
recommended start up curve
— Operate desuperheater when steam temperature are with
in 30 C of design point
— Slowly close start up and drain valve while maintain steam
flow > 10% MCR
107. 107
Feed bed material
— Bed material should be sand which size is according to
recommended size
— Start feed sand when bed temp >150 C
— Do not exceed firing rate >30% if bed pressure <20 mbar
otherwise overheating may occur for refractory and nozzle
— Continue feed bed material unit it reach 30 mbar
108. 108
Feed solid fuel
— Must have enough bed material
— Bed temperature > 600 C or manufacturer
recommendation or refer to NFPA85 Appendix H
— Pulse feed every 90 s
— Placing lime stone feeding, ash removal system
simultaneously
— Slowly decrease SUB firing rate while increasing solid fuel
feed rate
— Stop SUB one by one, observe bed temperature increasing
— Turn to auto mode control
109. 109
Rise to MCR
— Continue rise pressure and temperature according to
recommended curve until reach design point
— Drain bottom ash when bed pressure >45-55 mbar
— Slowly close start up valve
— Monitor concerning parameters
111. 111
6.4 Normal Operation
— Furnace and emssion
- monitor fluidization in hot
loop
- monitor gas side pressure drop
- monitor bed pressure
- monitor bed temperature
-monitor wind box pressure
- monitor SOx, Nox, CO
Furnace and Emission Monitoring
112. 112
6.4 Normal Operation
— Bottom ash drain
- automatic or manual draining
of bottom ash shall be judged by
commissioning engineer for the
design fuel.
- when fuel is deviated from the
design, operator can be judge by
themselves that draining need
to perform or not.
- bed pressure is the main
parameter to start draining
— Soot blower
- initiate soot blower to clean
the heat exchanger surface in
convective part
- frequent of soot blowing
depend on the degradation of
heat transfer coefficient.
- normally 10 C higher than
normal value of exhaust
temperature
Bottom ash and Soot Blower
113. 113
6.4 Normal Operation
— Boiler Walk Down
- boiler expansion joint
- Boiler steam drum
- Boiler penthouse
- Safety valve
- Boiler lagging
- Spring hanger
- Valve and piping
- Damper position
- Loop seal
- Bottom screw
- Combustion chamber
- Fuel conveyor
114. 114
6.4 Normal Operation
— Sizing Quality
- crushed coal, bed material, lime stone and bottom ash
sizing shall be periodically checked by the operator
- sieve sizing shall be performed regularly to make sure
that their sizing is in range of recommendation
115. 115
6.5 Normal Shut Down
1. Reduce boiler load to 50% MCR
2. Place O2 control in manual mode
3. Monitor bed temperature
4. Continue reducing load according to shut down curve
5. Maintain SH steam >20 C of saturation temperature
6. Start burner when bed temperature <750 C
7. Empty solid fuel and lime stone with bed material >650 C
8. Decrease SUB firing rate according to suggestion curve
9. Maintain drum level in manual mode
10. Stop solid fuel, line stone, sand feeding system
116. 116
6.5 Normal Shut Down
11. Maintain drum level near upper limit
12. Continue fluidizing the bed to cool down the system at 2
C/min by reducing SUB firing rate
13. Stop SUB at bed temperature 350 C
14. Continue fluidizing until bed temperature reach 300 C
15. Slowly close inlet damper of PAF and SAF so that IDF
can control furnace pressure in automatic mode
16. Stop all fan after damper completely closed
17. Stop HP blower 30 S after IDF stopped
18. Stop chemical feeding system when BFWP stop
19. Continue operate ash removal system until it empty
117. 117
6.5 Normal Shut Down
20. Open vent valve at drum and SH when drum pressure
reach 1.5-2 bar
21. Open manhole around furnace when bed temp < 300 C
118. 118
6.6 Emergency Shut down
— Boiler can be held in hot stand by condition about 8 hrs
— Hot condition is bed temp >650 C otherwise follow cold
star up procedure
— Boiler load should be brought to minimum
— Stop fuel feeding
— Wait O2 increase 2 time of normal operation
— Stop air to combustion chamber to minimize heat loss
119. 119
6.7 Hot restart
— Purge boiler if bed temperature < 600 C
— Start SUBs if bed temperature > 500 C
— Monitor bed temperature rise
— If bed temperature does not rise after pulse feeding solid
fuel. stop feeding and start purge
120. 120
6.8 Malfunction and Emergency
— Bed pressure
— Bed temperature
— Circulation
— Tube leak
— Drum level
121. 121
Bed Pressure
Bed pressure is an one of importance
parameter that effect on boiler efficiency
and reliability.
Measured above grid nozzle about 20 cm.
Pw
Pb
FI
Pf= 0
122. 122
Bed Pressure
— Effect of low bed pressure
- poor heat transfer
- boiler responds
- high bed temperature
- damage of air nozzle and refractory
— Effect of high bed pressure
- increase heat transfer
- more efficient sulfur capture
- more power consumption of fan
123. 123
Bed Pressure
— Cause of low bed pressure
- loss of bed material
- too fine of bed materials
- high bed temperature
— Cause of high bed pressure
- agglomeration
- too coarse of bed material
124. 124
Bed Temperature
— Measured above grid nozzle about
20 cm
— Measured around the furnace cross
section
— It is the significant parameter to
operate CFB boiler
125. 125
Bed temperature
— Effect of high bed temperature
- ineffective sulfur capture
- chance of ash melting
- chance of agglomeration
- chance to damage of air nozzle
126. 126
Bed temperature
— Cause of high bed temperature
- low bed pressure
- too coarse bed material
- too coarse solid fuel
- improper drain bed material
- low volatile fuel
- improper air flow adjustment
127. 127
Circulation
— Circulation is particular
phenomena of CFB boiler.
— Bed material and fuel are
collected at cyclone separator
— Return to the furnace via loop
seal
— HP blower supply HP air to
fluidize collected materials to
return to furnace
128. 128
Circulation
— Effect of malfunction circulation
- No circulation result in forced shut down
- high rate of circulation
- high circulation rate need more power of blower
- low rate of circulation
129. 129
Circulation
— Cause of malfunction circulation
- insufficiency air flow to loop seal nozzle
- insufficient air pressure to loop seal
- plugging of HP blower inlet filter
- blocking or plugging of loop seal nozzle
-
130. 130
Tube leak
— Water tube leak
- furnace pressure rise
- bed temperature reduce
- stop fuel feeding
- open start up valve
- don’t left low level of drum
- continue feed water until flue gas temp < 400 C
- continue combustion until complete
- small leak follow normal shut down
131. 131
Drum level
Sudden loss of drum level
- when the cause is known and immediately correctable
before level reach minimum allowable. Reestablish steam
drum level to its normal value and continue boiler
operation
-if the cause is not known. Start immediate shut down
according to emergency shut down procedure
132. 132
Drum level
Gradual loss of drum level
- boiler load shall be reduced to low load
- find out and correct the problem as soon as possible
- if can not maintain level and correct the problem, boiler
must be taken out of service and normal shut down
procedure shall be applied.
134. 134
Before maintenance work
— Make sure that all staff are understand about safety
instruction for doing CFB boiler maintenance work
— Make sure that all maintenance and safety equipments
shall be a first class
136. 136
6.1 Windbox Inspection
— Inspect sand inside windbox
after shutdown
— Drain pipe
— Crack
— Air gun pipe
— Refractory
— Crack, wear and fall down inspect
by hammer(knocking) if burner is
under bed design
Drain pipe
137. 137
6.2 Furnace Inspection
— Nozzle :
— Wear
— Fall-off
— Refractory
— Crack, wear and fall down inspect
by hammer knocking if burner is
under bed design
— Feed fuel port
— Wear
— Crack
— Burner
Refractory
Burner Feed Fuel
Nozzle
138. 138
6.2 Furnace Inspection
— Limestone port
— Crack
— Deform
— Refractory damage at connection
between port and refractory
— Secondary & Recirculation Air
port
— Crack
— Deform
— Refractory damage at connection
between port and refractory
— Bed Temperature
— Check thermo well deformation
— Check wear
Secondary & Recirculation Air port
139. 139
6.3 Kick-Out Inspection
— Refractory
— Wear
— Crack and fall down by
hammer(knocking)
— Water tube
— Wear
— Thickness
140. 140
6.3 Kick-Out Inspection
— Water Tube:
— Thickness measuring
— Erosion at corner
— CO Corrosion due to incomplete
combustion at fuel feed side.
— Defect from weld build up
— Water tube sampling for internal
check every 3 years
Inside water tube inspect by borescope
welded build up excessive metal because use welding rod
size bigger than tube thickness
141. 141
6.4 Superheat I (Wingwall)
— Water Tube:
— Thickness measuring
— Erosion at tube connection
— Refractory
— Crack and fall down by
hammer(knocking)
— Guard
— Crack
— fall down
142. 142
6.4 Superheat I (Omega Tube)
— Offset Water Tube:
— Thickness measuring
— Erosion at offset tube
— SH tube
— Thickness measuring
— Omega Guard
— Crack
— fall down
Omega Guard
Offset Water
Tube
143. 143
6.5 Roof
— Water Tube:
— Thickness measuring
— Erosion
— Refractory
— Crack, wear and fall down by
hammer(knocking)
144. 144
6.6 Inlet Separator
— Water Tube:
— Thickness measuring near opening
have more erosion than another
tube because of high velocity of flue
gas
— Refractory
— Crack, wear and fall down by
hammer(knocking)
145. 145
6.7 Steam Drum
— Surface :
— Surface were black by magnetite
— Deposits
— Deposits at bottom drum need to
check chemical analysis
— Cyclone Separator
— Loose
— Demister
— Blowdown hole
— Plugging
— U-Clamp
— Loose
Deposits at bottom drum
146. 146
6.8 Separator
— Central Pipe:
— Deformation
— Crack
— Refractory
— Wear at impact zone due to high
impact velocity
— Crack and fall down by
hammer(knocking)
147. 147
6.9 Outlet Separator
— Water Tube
— Tube Thickness
— Erosion
— Outlet Central Pipe:
—Support or Hook
— Refractory
—Crack and fall down by
hammer(knocking)
148. 148
6.10 Screen Tube
— Water Tube
— Thickness measuring upper part of
screen tube at corner have more
erosion than another area because
of high velocity of flue gas
— Guard
— Loose
— Refractory
— Crack and fall down by
hammer(knocking)
Weld build up or install guard to prevent tube erosion
upper part of screen tube at corner have more erosion
149. 149
6.11 Superheat Tube
— Tube
— Thickness measuring
— High erosion between SH tube and
wall
— Steam erosion due to improper soot
blower
— Guard
— Fall down
— Crack
150. 150
6.12 Economizer
— Water Tube
— Thickness measuring
— High erosion between economizer
tube and wall
— Steam erosion due to improper soot
blower
— Guard
— Fall down
— Crack
Guard
Install guard to
prevent tube erosion
151. 151
6.13 Air Heater
— Tube
— Cold end corrosion due to high
concentrate SO3 in flue gas
— Steam erosion due to improper soot
blower
Inlet air heater
Cold end corrosion due to SO3 in fluegas
154. 154
General safety precaution
— Electrical power shall be turned off before performing
installation or maintenance work. Lock out, tag out shall
be indicated
— All personal safety equipment shall be suit for each work
— Never direct air water stream into accumulation bed
material or fly ash. This will become breathing hazard
— Always provide safe access to all equipment ( plant from,
ladders, stair way, hand rail
— Post appropriate caution, warning or danger sign and
barrier for alerting non-working person
— Only qualify and authorized person should service
equipment or maintenance work
155. 155
General safety precaution
— Do not by-pass any boiler interlocks
— Use an filtering dust mask when entering dust zone
— Do not disconnect hoist unless you have made sure that
the source is isolated
156. 156
Equipment entry
— Never entry confine space until is has been cooled, purged
and properly vented
— When entering confine space such as separator, loop seal
furnace be prepared for falling material
— Always lock the damper, gate or door before passing
through them
— Never step on accumulation of bottom ash or fly ash. Its
underneath still hot
— Never use toxic fluid in confine space
— Use only appropriate lifting equipment when lift or move
equipment
157. 157
Equipment entry
— Stand by personnel shall be positioned outside a confine
space to help inside person incase of emergency
— Be carefully aware the chance of falling down when enter
cyclone inlet or outlet.
— Don not wear contact lens with out protective eye near
boiler, fuel handing, ash handing system. Airborne particle
can cause eye damage
— Don not enter loop seal with out installing of cover over
loop seal downcomer to prevent falling material from
cyclone
158. 158
Operating precautions
CFB boiler process
— Use planks on top of bed materials after boiler is cooled
down. This will prevent the chance of nozzle plugging
— Do not open any water valve when boiler is in service
— Do not operate boiler with out O2 analyzer
— Do not use downcomer blown donw when pressure > 7
bar otherwise loss of circulation may occure
— Do not operate CFB boiler without bed material
— When PA is started. PA flow to grid must be increase to
above minimum limit to fully fluidized bed maerial
— Do not operate CFB boiler with bed pressure > 80mbar.
This might be grid nozzle plugging
159. 159
Operating precautions
— on cold start up the rate of chance in saturated steam shall
not exceed 2 C/min
— On cold start up the change of flue gas temp at cyclone
inlet shall not exceed 70 C/min
— Do not add feed water to empty steam drum with
different temperature between drum metal and feed water
greater than 50 C
— All fan must be operated when add bed material
160. 160
Operating precautions
Refractory
— When entering cyclone be aware a chance of falling down
— Refractory retain heat for long period. Be prepared for hot
surface when enter this area
— An excessive thermal cycle will reduce the life cycle of
refractory
— After refractory repair, air cure need to apply about 24 hr
or depend on manufacturer before heating cure
— Heating cure shall be done carefully otherwise refractory
life will be reduced
161. 161
Operating precautions
Solid Fuel
— Chemical analysis of all solid fuel shall be determined for
first time and compared with OEM standard
— Sizing is important
— Burp feeding shall be performed during starting feeding
solid fuel instead of continuous feeding
163. 163
— Basic control
— Furnace control
— Main pressure control
— Main steam pressure control
— Drum level control
— Feed tank control
— Solid fuel control
— Primary air control
— Secondary air control
— Oxygen control
164. 164
Basic control
— Simple feedback control
PRIMARY VARIABLE
XT
K
A T A
f(x)
SET POINT
PROCESS
MANIPULATED VARIABLE
165. 165
Basic control
— Simple feed forward plus feedback control
PR IM ARY VARIABLE
XT
YT
SECO NDARY
VARIABLE
A T A
f(x)
MANIPULATED VARIABLE
PROCESS
SET POINT
K
166. 166
Basic control
— Simple cascade control
PRIMARY VARIABLE
XT
ZT
K
K
SET POINT
A AT
PROCESS
f(x)
MANIPULATED VARIABLE
SECONDARY
VARIABLE
167. 167
Basic control
CO
SP
PV
PID
Control Mode of PID
-MAN (Manual)
-AUT (Automatic)
-CAS (Cascade)
Signal to open0-15 m3/h
0-100% (closed à open)
4-20 mAElectrical signal 4-20 mA
Eng. Unit 0-15 m3/h
Percent 0-100 % 0-100%
168. 168
Feed water control
LT
PT
PIDPID
Make up water
Heating steam
Pressure
-Manual mode 0-100% heating steam valve
position
-Auto mode, specify pressure set point
-Temperature compensation
Level
-Manual mode 0-100% make up water valve
-Auto mode, specify level set point
-Temperature compensation
-Protection, high level over flow
169. 169
Drum Level control
DP feed
water pump
Control valve
A, SP
M, 0-100%
Main steam flow
Main steam Pressure
Manual mode, 0-100%
control valve
Auto mode, specify drum
level. Automatically adjust
valve
Protection
-lower limit
-2/3 principle
- 10 s delay
-Close steam valve for low level
173. 173
Primary air control
M
PID
FT
Auto
Cascade
PV
Manual
Manual: position of damper is
specified
Auto: desired air flow is specified by
operator
Cascade: set point is calculated from
master combustion
Flow (interlock) > minimum
PA wind box P > minimum
PA running
175. 175
HP Blower Control
— Pressure is controlled by control valve
— Control valve is connected to primary air
— It will release the air to primary air duct if pressure higher
than set point
— If operating unit stop due to disturbance or pressure fall
down, stand by unit shall be automatically started
— Pressure should be higher than 300 mbar, boiler interlock
— Pressure < 350 mbar parallel operation start
179. 179
Referenced
• Prabir Basu , Combustion and gasification in fluidized bed, 2006
• Fluidized bed combustion, Simeon N. Oka, 2004
• Nan Zh., et al, 3D CFD simulation of hydrodynamics of a 150 MWe circulating fluidized bed
boiler, Chemical Engineering Journal, 162, 2010, 821-828
• Zhang M., et al, Heat Flux profile of the furnace wall of 300 MWe CFB Boiler, powder
technology, 203, 2010, 548-554
• Foster Wheeler, TKIC refresh training, 2008
• M. Koksal and F. Humdullahper , Gas Mixing in circulating fluidized beds with secondary
air injection, Chemical engineering research and design, 82 (8A), 2004, 979-992