Design of Circulating Fluidized Bed Boilers

Selection, Applications, Operation, Maintenance, Performance Monitoring, Diagnostic Testing, Troubleshooting, Refurbishment, Common Problems and Solutions, Life Extension, and Economics

Introduction

This seminar will provide a comprehensive understanding of various types of circulating fluidized bed (CFB) boilers. All the components of CFB boilers including furnace, cyclones, economizers, superheaters, reheaters, ammonia injection systems, electrostatic precipitators, polishing dry scrubbers, fuel and sorbent feeding systems, bottom ash handling and extraction systems will be covered in detail. The design, selection considerations, operation, maintenance, diagnostic testing, troubleshooting, refurbishment, pay-back period, and economics as well as, emission limits, reliability, monitoring and control systems of CFB boilers will also be covered thoroughly. This seminar will focus on maximizing the efficiency, common problems and solutions, reliability, and longevity of CFB boilers by providing an understanding of the characteristics, selection criteria, common problems, and repair techniques, preventive and predictive maintenance. All the common problems encountered in CFB Boilers will be discussed in detail. This includes thermally induced failures, anchor system induced failures, water walls tube failures, NMEJ damages, clinker formation, refractory damages, APH tube chock-up. Solutions will be presented to each problem.

Several studies have confirmed that CFB boilers are the best method for power generation. This is due to their fuel flexibility, and lowest electricity cost among all types of boilers. This technology is in great demand due to various other advantages such as lower emissions as compared to other types of boilers and has a carbon footprint well below the norms laid down by the World Bank emission requirements. This seminar is a MUST for anyone who is involved in the selection, applications, or maintenance of circulating fluidized bed boilers, because it covers how this equipment operates, the latest maintenance techniques, and provides guidelines and rules that ensure successful operation of CFB boilers. This seminar will also provide up-dated information in respect to all the significant improvements that have been made to this equipment during the last two decades.

Who Should Attend

  • Engineers of all disciplines
  • Managers
  • Technicians
  • Maintenance personnel
  • Other technical individuals

Seminar Outcome

  • Circulating Fluidized Bed Boiler Advantages: Gain a thorough understanding of the advantages of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers Components and Systems: Learn about all components and subsystems of the various types of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers Applications, Performance and Economics: Examine the applications, performance and economics of Circulating Fluidized Bed Boilers.
  • Circulating Fluidized Bed Boiler Equipment: Learn about various equipment of circulating fluidized bed boilers including: furnaces, cyclones, economizers, superheaters, reheaters, ammonia injection systems, electrostatic precipitators, polishing dry scrubbers, fuel and sorbent feeding systems, bottom ash handling and extraction systems and materials.
  • Circulating Fluidized Bed Boilers Maintenance: Learn all the maintenance activities required for circulating fluidized bed boilers, to minimize their operating cost and maximize their efficiency, reliability, and longevity.
  • Circulating Fluidized Bed Boilers Environmental Emissions: Learn about the monitoring and control of environmental emissions from circulating fluidized boilers.
  • Circulating Fluidized Bed Boilers Instrumentation and Control Systems: Learn about the latest instrumentation and control systems of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers, Reliability and Testing: Increase your knowledge of predictive and preventive maintenance, reliability and testing of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers Selection and Applications: Gain a detailed understanding of the selection considerations and applications of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers Reliability, Refurbishment, and Life Extension Methods: Learn about the reliability, life cycle cost, profitability, refurbishment, and life extension methods for all types of circulating fluidized bed boilers.
  • Circulating Fluidized Bed Boilers Commissioning: Understand all the commissioning requirements of circulating fluidized bed boiler.
  • Circulating Fluidized Bed Boilers Codes and Standards: Learn all the codes and standards applicable for circulating fluidized bed boilers.

Training Methodology

The instructor relies on a highly interactive training method to enhance the learning process. This method ensures that all the delegates gain a complete understanding of all the topics covered. The training environment is highly stimulating, challenging, and effective because the participants will learn by case studies which will allow them to apply the material taught to their own organization.

Special Feature

Each participant will receive a copy of the following materials written by the instructor:

  • Power Generation Handbook published by McGraw-Hill in 2012 (800 pages)
  • Practical Circulating Fluidized Bed manual (300 pages)

Seminar Outline

  • Day One - Advantages of CFB Boilers, Components of CFB Boilers, Typical Arrangements of CFB Boilers, Hydrodynamics in CFB Boilers, Combustion in CFB Boilers, Heat Transfer in CFB Boilers, Design of CFB Boilers, CFB Boiler Operation, Maintenance of CFB Boilers, CFB Boiler Safety, Control Systems of CFB Boilers, Common Problems and Solutions of CFB Boilers

    Advantages of circulating fluidized bed combustion
  • Circulating fluidized bed combustion technology
  • Development of circulating fluidized bed boilers
  • Components of CFB boilers: wind box and grid nozzle, bottom ash drain, HP blower, cyclone separator, evaporative or superheat wing walls, fuel feeding system, refractory, solid recycle system (loop seal), wall tubes, kick out, limestone and sand system
  • Typical arrangements of CFB boilers
  • Hydrodynamic in CFB boilers: particle classification, regimes of fluidization, fast fluidization, hydrodynamic regimes in a CFB boiler, Hydrodynamic structure of fast beds
  • Combustion in CFB boilers: coal properties for CFB boiler, stage of combustion, factors affecting combustion efficiency, combustion in CFB, biomass combustion
  • Heat transfer in CFB boilers: gas to particle heat transfer, heat transfer in CFB boiler
  • Design of CFB boilers: design and required data, combustion calculations, heat and mass balance, furnace design, cyclone separator
  • CFB boiler operation: Requirements before starting, grid pressure drop test, cold start procedure, fill boiler procedure, start fan, boiler interlock, purge, start-up burner, drum and DA low level cut off, boiler warm-up, normal operation, normal shutdown, hot shutdown, hot restart,
  • Malfunction and emergency: bed pressure, bed temperature, circulation, tube leak, drum level
  • Maintenance of CFB boilers: Requirements before maintenance work, overview boiler maintenance, windbox inspection, furnace inspection, kick-out inspection, superheat (wingwalls), superheat (omega tube), roof inspection, inlet separator, steam drum, separator, outlet separator, screen tube, superheat tube, economizer inspection, air heater
  • Basic boiler safety: warnings, general safety precaution, equipment entry, operating precautions
  • CFB boiler control systems: Basic control, furnace control, main pressure control, main steam pressure control, drum level control, feed tank control, solid fuel control, HP blower control, primary air control, secondary air control, oxygen control, fuel oil control
  • Boiler commissioning procedure
  • Common problems and solutions of CFB boilers: wear problems in the boiler furnace, wastage in the boiler, thermally induced failures, anchor system induced failures, water wall tube failures (near lignite and subentry area), water wall tube failures at penthouse, main causes of tube failures, remedial actions, NMEJ failures, fitting of dust seal trap, clinker formation, remedial action taken, refractory damage, areas of major refractory damages, refractory damage in cyclones, APH tube chock-up, refractory failures at start-up burner and lignite entry area, chock-up in HP section

Day Two -  Design of a Circulating Fluidized Bed Boiler, Heat and Mass Transfer in a CFB Boiler, Furnace Design, CFB Boiler Configuration, CFB Design with External Fluid Bed Heat Exchanger, CFB Design Without Cyclone, Design of Heating Surfaces, Example of a Thermal Design of a CFB Boiler, Design of CFB Components

  • Design of a CFB boiler
  • Stoichiometric Calculations in a CFB boiler
  • Heat and Mass Transfer in a CFB boiler
  • Heat Balance
  • Calcination loss
  • Sulfation credit
  • Unburnt carbon loss in ash
  • Dry flue gas loss
  • Moisture loss
  • Division of solid stream (bed ash vs. fly ash)
  • Control of particle size distribution in bed
  • Furnace design
  • Furnace cross section
  • Width and depth ratio
  • Furnace openings
  • CFB boiler configuration
  • CFB boiler without external heat exchanger
  • CFB design with external fluid bed heat exchanger (FBHE)
  • Design with internal fluid bed heat exchanger
  • CFB design without cyclone
  • Cooled cyclone versus hot cyclone
  • Design of heating surfaces
  • Disposition of heating surfaces
  • Effect of fuel type
  • Biomass fired CFB boiler
  • Waste fired CFB boiler
  • Heat absorption in external heat exchanger (EHE)
  • Heat absorption in the furnace and back pass of the boiler
  • Energy and mass balance around CFB loop
  • Example of thermal design of a CFB boiler
  • Design of CFB components
  • Types of non-mechanical valves
  • Principle of operation of non-mechanical valves
  • L-valve, V-valve
  • Loop seal (seal pot or J-valve)
  • Design of L-valve
  • Maximum solid flow rate through L-valve
  • Practical consideration
  • Design of loop seal
  • Pressure balance
  • Size of loop seal
  • Design of loop seal
  • Pressure balance
  • Size of loop seal
  • Intrex with J-valve
  • Grate or fluidizing air distributor
  • Types of distributors
  • Design methods
  • Fluidizing air distributor for CFB
  • Nozzle plate design
  • Practical considerations
  • Plenum air loss
  • Sealing distributor
  • Attrition
  • Back-flow of solids

Day Three - Material Selection for a CFB Boiler, Corrosion and Erosion Potential in a CFB Boiler, Design Considerations of Refractory Lining, Potential Operating Problems with CFB Boilers, Failure or Degradation of Boiler Components, Design and Construction of CFB Boilers, Reduced Performance of the Total CFB Boiler or Specific Components, Prevention of Erosion and Corrosion in CFB Boilers, Maintenance Solutions to Common Problems Found in CFB Boilers, Supercritical Once-through Internal Recirculation-Circulating Fluidized-Bed (IR-CFB) Boilers for Power Generation, Ultra Supercritical Fluidized Bed (CFB) Boilers

  • Material Selection for a Circulating fluidized bed boiler
  • Pressure part materials in a CFB boiler
  • Corrosion potential in a CFB boiler
  • Erosion potential in a CFB boiler
  • Selection of tube materials
  • Commonly used materials in a CFB boiler
  • Carbon and alloy steels
  • Subcritical CFB boilers
  • Supercritical CFB boiler
  • Refractory and insulations
  • Properties of refractory material
  • Design considerations of refractory lining
  • Anchors
  • Areas of refractory use in a CFB boiler
  • Refractory application
  • Expansion joints in a CFB boiler
  • Material-related problems in a CFB boiler
  • Lower combustor
  • Water-cooled cyclones
  • Potential operating problems with CFB boilers: blockage of feed lines, loss in efficiency, material degradation, solid leakage, fouling, and agglomeration
  • Major Operating Problems in CFB Boilers
  • Failure of CFB Boiler Components
  • Degradation of CFB Boiler Components
  • Reduced Performance of the Whole CFB Boiler or Specific Components
  • Design and Construction of the Boiler
  • Options for Reduction in Erosion in CFB Boilers
  • Corrosion Inside CFB Boilers
  • Erosion-Corrosion
  • Fouling and Deposit Formation Inside CFB Boiler
  • Prevention of High Temperature Corrosion in CFB Boiler
  • Use of Additives to Prevent High-Temperature Corrosion in CFB Boiler
  • Reduction of Flue Gas Temperature at the Furnace Outlet
  • Use of Corrosion Resisting Alloys
  • Avoidance of Simultaneous Occurrence of High Gas Temperature and High Wall Temperature
  • Avoidance of Contact of High Wall Temperature and Corrosion Agents
  • Refractory Failure
  • Thermally Induced Failures
  • Anchor Failures
  • Erosion Failures
  • Maintenance Issues
  • Design Audit
  • Material Audit
  • Preventive and Remedial Measures for Fireside Corrosion
  • Preventive Maintenance for Refractory
  • Operating Issues
  • Safety Issues
  • Wind-box Explosion
  • Reduced Boiler Performance
  • High Furnace Temperature
  • Excess Emission of NOx and SO2
  • Bed Agglomeration
  • Fouling
  • Loop-seal Problems
  • Methods used to improve the heat rate of circulating fluidized bed boilers
  • Supercritical Once-Through Internal Recirculation-Circulating Fluidized Bed Boilers (IR-CFB) Boilers for Power Generation
  • Supercritical once-through circulating fluidized bed with in-bed heat exchanger (IBHX)  
  • Supercritical once-through circulating fluidized bed design study
  • Ultra supercritical circulating fluidized bed boilers