This document summarizes parameters that must be maintained for efficient operation of AFBC boilers, including bed height, air pressures, temperatures, fuel size, bed material specifications, and air-to-fuel ratios. It also describes boiler emergencies such as low drum level, high furnace draft, tube failures, and flame failure; their causes and effects; and recommended actions to address them. The document aims to provide guidance on efficient and safe operation of boilers to prevent boiler explosions.
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.
The Presentation discusses the Air-Heater Performance Indices and the Boiler Performance calculation. One can Calculate the air ingress in the air-heater and the boiler and losses incurred thereby. The presentation also describes in details about the boiler efficiency and its calculation.
Boilers are closed vessels made of steel that transfer heat from fuel combustion to water to generate steam. They come in two main types: fire tube boilers where hot gases pass through tubes surrounded by water, and water tube boilers where water passes through tubes surrounded by hot gases. Boilers must generate maximum steam, be lightweight, safe, affordable, and easy to access for maintenance. Steam is used for power generation, heating, and in chemical processes. Boiler efficiency is important and various accessories like economizers and superheaters are used to improve it. Understanding boilers is essential for the chemical industry as most used are high efficiency, safe water tube designs.
The slides describe the factors that affect the performance of AFBC boilers and how to improve the performance of AFBC boilers. These type of boilers are mainly used in the below 100 MW power boilers.
The document discusses the HP/LP bypass system used in thermal power stations. The bypass system allows live steam from the boiler to bypass the turbine and be dumped into the condenser. This allows the boiler to continue operating during turbine trips or startup before the turbine is up to temperature. It comprises HP and LP bypass valves, spray valves, and other components. The bypass system cuts startup time, allows boiler operation during trips, and helps match boiler and turbine temperatures for efficient operation.
This document discusses the control and instrumentation system for the Jaypee Bina Thermal Power Plant's 2x250 MW furnace safeguard and supervisory system (FSSS). The FSSS is designed to safely start up and shut down the boiler and prevent operator errors. It monitors the burner block assembly and controls the furnace purge sequence, oil gun operation in pair or elevation mode, and high energy arc igniter system to safely initiate combustion. The FSSS ensures maximum safety and efficiency during plant operation.
This document discusses materials used in boiler and furnace components. It describes that boiler drums are made from Ducal W30 steel due to its high strength. Downcomers and riser tubes are constructed from low-carbon steel alloys. Water walls contain carbon, silicon, manganese, sulfur and phosphorus. Superheaters and reheaters can be made from ferritic steel, austenitic steel, or nickel-based alloys like Esshete 1250. Economizers and soot blowers use low-carbon steel and heat-resistant stainless steel respectively.
Effect of Coal Quality and Performance of Coal pulverisers / MillsManohar Tatwawadi
The presentation discusses about the change in performance parameters of a pulveriser due to change in coal quality and the measurement of performance and troubleshooting of coal firing system as a whole.
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.
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”
This document summarizes different processes for removing carbon dioxide from ammonia plant streams. It discusses why CO2 removal is important, and describes common processes like MEA and MDEA absorption. The Benfield process uses hot potassium carbonate solution promoted by diethanolamine to physically absorb CO2. Issues with the Benfield process include foaming, corrosion, and vanadation problems. Retrofitting with a new amine promoter called LRS 10 can improve CO2 removal efficiency and reduce energy costs for the Benfield process.
This document contains frequently asked questions and answers about steam turbines. It discusses issues like speed variation, vibration, deposits, erosion, washing, compounding, and monitoring. Questions cover topics such as reducing speed variation through governor adjustments, the effects of deposits on efficiency, solid particle erosion, monitoring internal efficiency, and reducing vibration damage through blade design modifications. Causes and remedies of issues like governor lubrication problems, safety trip valve trips, and foreign particle damage are also addressed.
The document provides information on governing systems and common problems encountered. It discusses:
1. The key components of a governing system block diagram including pumps, valves, filters and overspeed testers.
2. Cleaning procedures and stroke check requirements for governing systems.
3. Parameters that should be followed including pressures, signals, valve lifts and temperatures.
4. Common governing problems like hunting, chattering, and sudden speed variations.
5. Case studies examining issues like improper servomotor assembly and a bent pilot valve spring causing load hunting.
This document provides an overview of boiler fundamentals and best practices. It discusses steam production and uses, steam purity and quality, types of boilers including fire tube, water tube and waste heat boilers. It also covers basic boiler principles, calculations, and internal water treatment programs. Effective internal water treatment is needed to control deposition, corrosion and carryover in boilers. Common treatment programs use polymers and phosphates to precipitate hardness and control sludge through crystal modification and dispersion.
This document provides information on maintaining solid fuel and oil fired boilers. It discusses the importance of proper maintenance for safety, availability, efficiency and cost effectiveness. Key aspects covered include feedwater and boiler water quality control, fuel quality monitoring, combustion optimization, and regular safety checks. Recommended maintenance activities are outlined for daily, weekly, monthly, quarterly, half-yearly and yearly timeframes.
The document provides information on protection and interlocks in modern power plants. It discusses various boiler safety protections that detect abnormal conditions like high or low drum level, high steam pressure or temperature. It also describes interlocks that isolate faulty equipment to prevent damage and switch on backup equipment. Specific causes, effects and actions are outlined for issues like drum level high/low, flame failure, boiler feed pump failure, and loss of fans. The protections and interlocks are designed to trip the boiler or isolate equipment in emergencies to maintain continuous and reliable plant operation.
The document discusses points related to sub critical and super critical boiler design, including boiler design parameters, chemical treatment systems, operation, feedwater systems, boiler control, and startup curves. It provides explanations of sub critical and super critical boiler technologies, comparing drum type sub critical boilers to drumless super critical boilers. Key differences in operation and response to load changes are highlighted.
The document provides information on the commissioning process for a boiler. It involves several key steps: air leakage and hydro testing, ensuring boiler auxiliaries are ready, gas distribution testing, light up of the boiler, alkali boil-out and passivation to clean the boiler, steam blowing of piping, safety valve testing, and finally coal firing. The commissioning aims to make the boiler and its systems available for safe, smooth, and reliable operation after erection is completed.
The primary reformer at Agrium's Fort Saskatchewan Nitrogen Operations experienced a massive failure following a routine startup. Almost all 260 catalyst tubes in the radiant section failed, and the air-steam preheat coil was damaged, resulting in lost production. An investigation found that additional burners were lit without checks of flame impingement or tube temperature, causing the flue gas temperature to reach over 1,000°C and melt the tubes. Over 50% of tubes failed, with molten metal solidifying in the catalyst. Kellogg Brown and Root were contracted to replace all failed components and repair the furnace to restore production as soon as possible.
This document provides an overview of the Delta V distributed control system (DCS) being used. It describes the key components of the Delta V system including the engineering workstation, application workstation, operator workstations, controllers, I/O modules, and typical network schematic. It also summarizes the functions and features of the operator workstation including the buttons, common display elements or "dynamos" like gauges and valves, and the faceplates used for process monitoring and control.
This document describes different types of valves and their functions, including:
- On-off valves like gate valves, plug valves, ball valves which are used to fully open or close flow.
- Throttling valves like globe valves and butterfly valves which are used to control the rate of flow.
- Check valves which allow flow in only one direction to prevent backflow.
- Pressure relief valves which open at a set pressure to release excess pressure and protect systems.
- Control valves and the components that are used in pneumatic pressure control systems.
This document discusses basic instrumentation concepts and components. It defines instrumentation and process control, and describes their functions. It also covers common process measurements like temperature, pressure, flow, and level. For each it discusses units of measurement, measurement elements and principles, and examples of measurement devices. Finally, it briefly introduces how instrumentation signals are transmitted from field devices to control systems.
O documento explica o conceito de taxas proporcionais no regime de capitalização simples e fornece exemplos de como converter entre taxas anuais, mensais e diárias. Ele também mostra como programar uma calculadora HP-12C para calcular taxas equivalentes entre períodos de tempo diferentes.
An explosion occurred at a utility boiler, injuring three personnel who were attempting to restart it. The investigation found they had used an unauthorized temporary bypass method for lighting the boiler that involved opening bypass valves without first closing block valves downstream, allowing LPG to enter the furnace. Non-compliance with safety procedures on management of change and control of equipment defects contributed to the accident. Lessons included following safe operating procedures, obtaining authorization for changes, and ensuring all personnel are properly trained.
O documento discute os riscos de explosão em caldeiras a vapor. Ele explica que explosões podem ocorrer devido a superaquecimento, choques térmicos, defeitos de fabricação, corrosão, aumento excessivo de pressão e falhas no lado dos gases. O autor enfatiza a importância de entender as causas de explosão para projetar, operar e inspecionar caldeiras de forma segura.
Practical Distributed Control Systems (DCS) for Engineers and TechniciansLiving Online
This workshop will cover the practical applications of the modern Distributed Control System (DCS). Whilst all control systems are distributed to a certain extent today and there is a definite merging of the concepts of a DCS, Programmable Logic Controller (PLC) and SCADA and despite the rapid growth in the use of PLC’s and SCADA systems, some of the advantages of a DCS can still be said to be Integrity and Engineering time.
Abnormal Situation Management and Intelligent Alarm Management is a very important DCS issue that provides significant advantages over PLC and SCADA systems.
Few DCSs do justice to the process in terms of controlling for superior performance – most of them merely do the basics and leave the rest to the operators. Operators tend to operate within their comfort zone; they don’t drive the process “like Vettel drives his Renault”. If more than one adverse condition developed at the same time and the system is too basic to act protectively, the operator would probably not be able to react adequately and risk a major deviation.
Not only is the process control functionality normally underdeveloped but on-line process and control system performance evaluation is rarely seen and alarm management is often badly done. Operators consequently have little feedback on their own performance and exceptional adverse conditions are often not handled as well as they should be. This workshop gives suggestions on dealing with these issues.
The losses in process performance due to the inadequately developed control functionality and the operator’s utilisation of the system are invisible in the conventional plant and process performance evaluation and reporting system; that is why it is so hard to make the case for eliminating these losses. Accounting for the invisible losses due to inferior control is not a simple matter, technically and managerially; so it is rarely attempted. A few suggestions are given in dealing with this.
Why are DCS generally so underutilised? Often because the vendor minimises the applications software development costs to be sure of winning the job, or because he does not know enough about the process or if it is a green-field situation, enough could not be known at commissioning time but no allowance was made to add the missing functionality during the ramp-up phase. Often the client does not have the technical skills in-house to realise the desired functionality is missing or to adequately specify the desired functionality.
This workshop examines all these issues and gives suggestions in dealing with them and whilst not being by any means exhaustive provides an excellent starting point for you in working with a DCS.
MORE INFORMATION: http://www.idc-online.com/content/practical-distributed-control-systems-dcs-engineers-technicians-2
This document provides an overview of distributed control systems (DCS) and programmable logic controllers (PLC). It defines DCS and PLCs, compares them, and describes their basic components and functions. The key aspects covered are:
1) DCS are integrated control systems used for complex, large-scale processes, while PLCs are used for discrete and small-scale control.
2) Both have centralized processing units and input/output modules to interface with field devices.
3) DCS are designed for continuous long-term use, while PLCs are more modular project-based systems.
The document provides an overview of various instrumentation topics including instrument symbols, flow and pressure measurement, temperature measurement, control valves, level measurement and control loops. It discusses common instrument types for measuring these process variables such as orifice plates, pressure gauges, thermocouples and level switches. It also covers related concepts such as sizing control valves using Cv, installing instruments properly and calibrating instruments.
This document provides an overview of instrumentation and process control. It defines key terms like instrumentation, process, transducer, signal, loop, controller, and interlock. It describes common process parameters measured like pressure, level, temperature, and flow. It discusses primary measuring devices and principles for each process variable. It also covers control valves and automation systems like DCS, PLC, and SCADA.
The document discusses control system trends and different distributed control system (DCS) architectures. It describes the evolution of DCS from centralized to distributed control with fieldbus connectivity. It provides examples of DCS installations and components of DCS systems from manufacturers like Honeywell, Yokogawa, and ABB. These include control stations, input/output modules, networks, and the use of Windows-based control.
The document provides information on a presentation covering the introduction, advantages, and technical details of a circulating fluidized bed (CFBC) boiler. Key points include:
- The CFBC boiler mixes fuel and limestone in a turbulent, fluidized environment for efficient combustion and sulfur capture.
- Advantages include high efficiency, fuel flexibility, low pollution, and no clinker formation.
- Technical details provided include the water and steam circuits, design features, boiler parameters, coal analysis, heating surfaces, and maintenance schedules.
This document provides an overview of steam boiler basics, including:
- Low and high pressure boiler classifications
- Common firetube and watertube boiler designs
- Key boiler components like trim, blowdown equipment, and feedwater systems
- Important considerations for boiler operation like water treatment, combustion air requirements, and preventing short cycling
- Components of a steam boiler room like softeners, deaerators, and economizers
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 information about steam boilers, including:
- Steam boilers generate steam by transferring heat from fuel combustion to water. They are closed vessels made of steel.
- Boilers are classified based on factors like the position of the furnace, number of tubes, circulation method, and intended use. Common types include fire-tube, water-tube, internally-fired, and externally-fired boilers.
- Key components include the boiler shell, furnace, tubes, safety valves, water level indicators, and accessories like economizers, superheaters, and feed pumps. Proper selection depends on factors like steam needs, fuel availability, and costs.
This document provides information about steam generators and coal-fired power plants. It discusses the basics of how coal is converted to electricity in several steps: coal is burned to create heat energy, which turns water into high-pressure steam, which spins turbines connected to generators to create electrical energy. It also describes the major components involved like boilers, turbines, condensers, and alternators. Furthermore, it compares the technical specifications and costs of 660MW and 500MW subcritical and supercritical steam generators.
Steam generators/boilers convert the chemical energy of fossil fuels into thermal energy, which is then transferred to water to produce high-pressure steam. There are various types of steam generators classified by capacity, pressure, design, and heating surface arrangement. Key boiler types discussed include fire tube boilers, water tube boilers, locomotive boilers, Babcock and Wilcox boilers, and Cochran boilers. Selection of boilers depends on factors like codes and standards, load requirements, number of boilers needed, and special considerations like space and replacement needs.
This document discusses heat rate audits in thermal power plants. It aims to identify causes of efficiency losses that increase heat rate. Some key points:
- Heat rate is the amount of heat input (fuel) required per unit of power generated and impacts generation costs. Lower heat rates reduce costs.
- Losses occur in the boiler, turbine, condenser/feedwater systems, circulating water system, and from electrical/steam auxiliaries.
- Common causes of higher heat rates include incomplete combustion, turbine erosion, condenser tube fouling, and electrical auxiliary inefficiencies.
- Tracking plant parameters and conducting monthly performance tests can identify losses and guide improvement efforts to lower heat rates.
The document provides information about steam generators and coal-fired power plants. It discusses the basics of how coal is converted to electricity through a thermal cycle. Coal is burned in a boiler to produce superheated steam, which spins a turbine connected to a generator to produce electrical energy. The steam is then condensed in a condenser, and the condensate is returned to the boiler via feedwater pumps, completing the cycle. The document also contains details about India's major coal-fired power plants and their locations.
This document provides information about the sugar milling and boiling house processes. It discusses the key components and processes involved, including:
- Milling house which uses mills to extract juice from sugarcane with 95-97% efficiency. Modern mills use improved cane preparation, feeding, and three-roller designs.
- Boiling house which uses steam boilers to heat water into steam to transfer heat to processes like juice heating and pan boiling. Water tube boilers are most common and produce steam at higher pressures.
- Steam distribution which sends steam generated to various processes like juice heating (15-18%), evaporation (2-10%), and pan boiling (20-25%).
Boiler & co generation presentation finished not yetRohit Meena
This document provides information about boilers and co-generation plants. It discusses the major components of a boiler which include the coal handling plant, co-generation plant, ash handling plant, and boiler. It then describes what a boiler is, the process of steam generation, and that steam volume increases tremendously from water. It also discusses co-generation plants and how they simultaneously produce power and thermal energy from the same primary energy source.
Boiler & co generation presentation finished not yetRohit Meena
This document provides information on boilers and co-generation plants. It discusses the major components of such plants including the DM plant, coal handling plant, co-generation plant, ash handling plant, and boiler. It then goes into details about boilers, describing them as enclosed pressure vessels that use combustion to heat water into steam. It discusses the process of evaporation and how steam volume increases. The document also provides information on co-generation plants, fluidized bed combustion boilers, auxiliary equipment for boilers like fans and heat exchangers, and details on pulverized fuel boilers.
Boiler & co generation presentation finished not yetdrazil
This document provides information on boilers and co-generation plants. It discusses the major components of such plants including the DM plant, coal handling plant, co-generation plant, ash handling plant, and boiler. It then goes into details about boilers, describing them as enclosed pressure vessels that use combustion to heat water into steam. It discusses the process of evaporation and how steam volume increases. The document also provides information on co-generation plants, fluidized bed combustion boilers, auxiliary equipment for boilers like fans and heat exchangers, and details on pulverized fuel boilers.
Thermal Power plant familarisation & its AuxillariesVaibhav Paydelwar
PPT in Relation to Power Plant familarisation, Coal to Electricity Basics,Power Plant cycles, Concepts of Supercritical Technology Boiler, Concepts Of BTG Package as well as Balance of Plant
COAL BASED THERMAL POWER PLANTS (UNIT-1).pptxCHANDRA KUMAR S
Thermal power plants convert the chemical energy stored in fossil fuels into heat energy by burning coal. The heat boils water to produce steam, which powers turbines that generate electricity. There are four main circuits in a thermal power plant: coal and ash, air and flue gas, water and steam, and cooling water. Coal is burned to heat water and produce steam, which spins turbines to generate electricity. The resulting ash is removed and stored while flue gases are treated before being released into the atmosphere.
This document discusses steam boilers, their classifications, components, and accessories. It begins by defining steam generators/boilers as equipment used for producing and transferring steam. It then classifies boilers based on factors like the relative position of hot gases and water, method of firing, pressure, circulation method, and intended use. Examples of fire tube and water tube boilers are described in more detail, including locomotive, Lancashire, and Babcock & Wilcox boilers. Mountings for safety and control are outlined. Finally, essential characteristics of a good boiler and common accessories are summarized.
Basic Concepts of a Boiler in powerplant.pptxSHIVKUMARYASH
BOILER” means any closed vessel exceeding
22.75 litres in capacity and is used expressively for generating steam under pressure and includes any mounting or other fitting attached to such vessel which is wholly or partly under pressure when the steam is shut off.
The document discusses factors affecting boiler selection and types of boilers. It describes key factors like steam output required, working pressure, fuel availability, and cost. Fire tube boilers discussed include Lancashire, Cornish, locomotive, and Cochran. Water tube boilers mentioned are suitable for pressures above 10 bar and output over 7000 kg/hr, such as Babcock & Wilcox and Stirling. Details are provided on Lancashire, locomotive, B&W, and Stirling boiler designs. Mountings, accessories, circulation methods, and high pressure boilers are also covered.
This document provides information on boiler operation, maintenance, and safety. It discusses boiler design and classifications. Fire-tube boilers have tubes that hot gases pass through, while water-tube boilers have water passing through tubes surrounded by hot gases. Key parts of boilers are also outlined like the pressure gauge, water level indicator, safety valve, and blow-off cock. Water-tube boilers are more efficient with higher steam pressures but require more maintenance.
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.
The document discusses different types of power plants and steam boilers. It describes the key components and circuits of a steam power plant which uses coal as fuel. Various types of steam boilers are explained, including fire tube boilers, water tube boilers, high pressure boilers, supercritical boilers, and fluidized bed boilers. Fluidized bed boilers allow the combustion of low grade fuels and have lower emissions. They operate at lower temperatures than conventional boilers.
Similar to Safe Operation and Explosions in Boilers (20)
This document discusses boiler water treatment from Thermax Limited. It covers water chemistry issues like scaling, corrosion and carryover and their causes. It describes different treatment programs like phosphate, amine and oxygen scavenger dosing. Key steps of treatment include chemical dosing, monitoring water parameters, and preservation during shut down. The objective is to maintain water quality, prevent equipment damage, and ensure reliability and efficiency.
Thermax Limited provides consulting services for efficient steam systems, including piping design, equipment selection, and design of condensate recovery and waste heat recovery systems. They offer utilities audits to analyze steam, compressed air, cooling, and power systems with the goal of optimizing costs. Their expertise includes selection and sizing of equipment such as pressure reducing stations, traps, and insulation. High-pressure condensate recovery systems can provide fuel savings of 15-20% by recovering heat from flash steam and condensate.
This document discusses new technologies in process heating. It covers combustion technologies for fossil fuels and biomass, as well as biomass boiler designs. Challenges in biomass combustion include low density fuel with high moisture and emissions. New combustion technologies aim to improve efficiency, reduce emissions, and be compact and cost-effective. Computational tools like CFD and FEA are helping develop new products and solve design problems. Condensing technology allows recovering latent heat to boost efficiencies above 100%, but introduces material challenges.
The document is a presentation on efficient operation and maintenance of boilers. It discusses typical water and fireside problems in low pressure, medium pressure, and high pressure boilers. It provides best practices for chemical treatment and operating boilers at different pressures. Common problems discussed include hard scale, soot, corrosion, deposition, and tube failures. The presentation encourages contacting Ion Exchange India for assistance with boiler water treatment and chemical products.
The document discusses efficient steam systems and generation. It provides information on fuel prices and calorific values, boiler efficiency and cost of steam for different fuels. It discusses optimal steam generation systems and factors to consider like steam demand, fuel selection, and cogeneration feasibility. Graphs show measured losses from boilers and comparisons of efficiency methods. The document emphasizes the importance of monitoring boiler parameters, automation, and intelligent control systems to improve efficiency. It also covers steam distribution, insulation, venting, metering and trapping to reduce losses across the steam system.
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.
GMR Warora Energy monitors boiler performance using online and offline tools to identify losses and improve efficiency. Key performance indicators like dry flue gas loss and unburnt carbon are tracked. Corrective actions include optimizing excess air, mill performance, air preheater cleaning, and chemical treatment. This approach helps reduce fuel costs and improve availability. Monitoring tools help detect issues and 1% increased efficiency saves $82 million annually for a 600 MW plant.
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.
The document summarizes the failure history and root cause analysis of the superheater tubes in two high pressure boilers. The superheater tubes experienced premature failures due to overheating, with surface temperatures reaching 550-600°C. Analysis found the superheater design had too low pressure drop, inadequate steam velocities, and lack of screen tubes. Modifications reduced tube count, implemented a double stage design with attemperation, upgraded metallurgy, and increased pressure drop. The modifications eliminated overheating failures and improved performance.
Cheema Boilers Limited is hosting a national workshop on efficient operation and maintenance of boilers in Visakhapatnam on December 7-8, 2015. The document discusses various types of boilers such as water tube boilers, fire tube boilers, and biomass-fired boilers. It also covers topics like boiler efficiency calculation, flue gas emissions, dust collection systems, combustion air calculation and boiler water treatment.
This document summarizes the experience of indigenizing (domesticating) the waste heat boiler system at Vizag Steel Plant in India. Originally using Russian-made boilers, problems with erosion, corrosion, and maintenance were addressed. Tube bundles were replaced with Indian-made alloy steel tubes, reducing erosion. Bi-metallic corrosion at tube brackets was eliminated by specifying compatible materials. New single-shaft boilers were installed with larger dimensions to reduce gas velocity by 70%, preventing erosion. Refractory walls requiring frequent repair were replaced in future boilers. Through material selection, design changes, and replacing components, the Russian system was successfully adapted for local manufacturing and conditions.
This document discusses online efficiency and diagnostics of coal-fired boilers. It provides background on Steag Energy Services and Steag O&M Company. It then covers topics like power plant efficiency calculations, effects of parameters like pressure and temperature on efficiency, sources of losses in the Rankine cycle, challenges like air preheater issues, and potential areas for improvements like cleaning tubes and turbines, condenser maintenance, and installing online performance monitoring software. Finally, it outlines how Steag O&M Company can help with operations, maintenance, commissioning, and benchmarking to reduce generation costs.
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 document discusses efficient operation and maintenance of boilers at NTPC Simhadri. It provides an overview of NTPC's journey and capacity, describes the types of boilers used, and outlines best practices adopted to reduce boiler tube leakages. These include improved startup procedures, monitoring of chemical parameters, thorough inspections and testing, and implementation of new technologies like acoustic leak detectors and process instrumentation systems. The presentation aims to share experiences in achieving zero boiler tube failures through preventative maintenance practices.
Online music portal management system project report.pdfKamal Acharya
The iMMS is a unique application that is synchronizing both user
experience and copyrights while providing services like online music
management, legal downloads, artists’ management. There are several
other applications available in the market that either provides some
specific services or large scale integrated solutions. Our product differs
from the rest in a way that we give more power to the users remaining
within the copyrights circle.
Profiling of Cafe Business in Talavera, Nueva Ecija: A Basis for Development ...IJAEMSJORNAL
This study aimed to profile the coffee shops in Talavera, Nueva Ecija, to develop a standardized checklist for aspiring entrepreneurs. The researchers surveyed 10 coffee shop owners in the municipality of Talavera. Through surveys, the researchers delved into the Owner's Demographic, Business details, Financial Requirements, and other requirements needed to consider starting up a coffee shop. Furthermore, through accurate analysis, the data obtained from the coffee shop owners are arranged to derive key insights. By analyzing this data, the study identifies best practices associated with start-up coffee shops’ profitability in Talavera. These findings were translated into a standardized checklist outlining essential procedures including the lists of equipment needed, financial requirements, and the Traditional and Social Media Marketing techniques. This standardized checklist served as a valuable tool for aspiring and existing coffee shop owners in Talavera, streamlining operations, ensuring consistency, and contributing to business success.
20CDE09- INFORMATION DESIGN
UNIT I INCEPTION OF INFORMATION DESIGN
Introduction and Definition
History of Information Design
Need of Information Design
Types of Information Design
Identifying audience
Defining the audience and their needs
Inclusivity and Visual impairment
Case study.
In May 2024, globally renowned natural diamond crafting company Shree Ramkrishna Exports Pvt. Ltd. (SRK) became the first company in the world to achieve GNFZ’s final net zero certification for existing buildings, for its two two flagship crafting facilities SRK House and SRK Empire. Initially targeting 2030 to reach net zero, SRK joined forces with the Global Network for Zero (GNFZ) to accelerate its target to 2024 — a trailblazing achievement toward emissions elimination.
Software Engineering and Project Management - Introduction to Project ManagementPrakhyath Rai
Introduction to Project Management: Introduction, Project and Importance of Project Management, Contract Management, Activities Covered by Software Project Management, Plans, Methods and Methodologies, some ways of categorizing Software Projects, Stakeholders, Setting Objectives, Business Case, Project Success and Failure, Management and Management Control, Project Management life cycle, Traditional versus Modern Project Management Practices.
Exploring Deep Learning Models for Image Recognition: A Comparative Reviewsipij
Image recognition, which comes under Artificial Intelligence (AI) is a critical aspect of computer vision,
enabling computers or other computing devices to identify and categorize objects within images. Among
numerous fields of life, food processing is an important area, in which image processing plays a vital role,
both for producers and consumers. This study focuses on the binary classification of strawberries, where
images are sorted into one of two categories. We Utilized a dataset of strawberry images for this study; we
aim to determine the effectiveness of different models in identifying whether an image contains
strawberries. This research has practical applications in fields such as agriculture and quality control. We
compared various popular deep learning models, including MobileNetV2, Convolutional Neural Networks
(CNN), and DenseNet121, for binary classification of strawberry images. The accuracy achieved by
MobileNetV2 is 96.7%, CNN is 99.8%, and DenseNet121 is 93.6%. Through rigorous testing and analysis,
our results demonstrate that CNN outperforms the other models in this task. In the future, the deep
learning models can be evaluated on a richer and larger number of images (datasets) for better/improved
results.
Conservation of Taksar through Economic RegenerationPriyankaKarn3
This was our 9th Sem Design Studio Project, introduced as Conservation of Taksar Bazar, Bhojpur, an ancient city famous for Taksar- Making Coins. Taksar Bazaar has a civilization of Newars shifted from Patan, with huge socio-economic and cultural significance having a settlement of about 300 years. But in the present scenario, Taksar Bazar has lost its charm and importance, due to various reasons like, migration, unemployment, shift of economic activities to Bhojpur and many more. The scenario was so pityful that when we went to make inventories, take survey and study the site, the people and the context, we barely found any youth of our age! Many houses were vacant, the earthquake devasted and ruined heritages.
Conservation of those heritages, ancient marvels,a nd history was in dire need, so we proposed the Conservation of Taksar through economic regeneration because the lack of economy was the main reason for the people to leave the settlement and the reason for the overall declination.
An Internet Protocol address (IP address) is a logical numeric address that is assigned to every single computer, printer, switch, router, tablets, smartphones or any other device that is part of a TCP/IP-based network.
Types of IP address-
Dynamic means "constantly changing “ .dynamic IP addresses aren't more powerful, but they can change.
Static means staying the same. Static. Stand. Stable. Yes, static IP addresses don't change.
Most IP addresses assigned today by Internet Service Providers are dynamic IP addresses. It's more cost effective for the ISP and you.
How to Manage Internal Notes in Odoo 17 POSCeline George
In this slide, we'll explore how to leverage internal notes within Odoo 17 POS to enhance communication and streamline operations. Internal notes provide a platform for staff to exchange crucial information regarding orders, customers, or specific tasks, all while remaining invisible to the customer. This fosters improved collaboration and ensures everyone on the team is on the same page.
Social media management system project report.pdfKamal Acharya
The project "Social Media Platform in Object-Oriented Modeling" aims to design
and model a robust and scalable social media platform using object-oriented
modeling principles. In the age of digital communication, social media platforms
have become indispensable for connecting people, sharing content, and fostering
online communities. However, their complex nature requires meticulous planning
and organization.This project addresses the challenge of creating a feature-rich and
user-friendly social media platform by applying key object-oriented modeling
concepts. It entails the identification and definition of essential objects such as
"User," "Post," "Comment," and "Notification," each encapsulating specific
attributes and behaviors. Relationships between these objects, such as friendships,
content interactions, and notifications, are meticulously established.The project
emphasizes encapsulation to maintain data integrity, inheritance for shared behaviors
among objects, and polymorphism for flexible content handling. Use case diagrams
depict user interactions, while sequence diagrams showcase the flow of interactions
during critical scenarios. Class diagrams provide an overarching view of the system's
architecture, including classes, attributes, and methods .By undertaking this project,
we aim to create a modular, maintainable, and user-centric social media platform that
adheres to best practices in object-oriented modeling. Such a platform will offer users
a seamless and secure online social experience while facilitating future enhancements
and adaptability to changing user needs.
A brief introduction to quadcopter (drone) working. It provides an overview of flight stability, dynamics, general control system block diagram, and the electronic hardware.
1. National Workshop on
“Efficient Operation and Maintenance of Boilers”
organized by National Productivity Council
at Visakhapatnam(AP)
Presented By:
Vikas shrivastava & Akhilesh Tiwari
under guidance of Mr. R N Yadav and Mr. A K Saxena
From JAYPEE SIDHI CEMENT PLANT
, SIDHI,MP
2. EFFICIENT AND SAFE OPERATION
OF BOILERS AND PREVENTION
OF BOILER EXPLOSION
BY JAYPEE SIDHI CEMENT PLANT, SIDHI (M.P.)
3. PARAMETERS REQUIRED TO BE MAINTAINED STRICTLY
FOR EFFICIENT OPERATION OF AFBC BOILERS
Bed Height/FD Air Pressure
Primary Air Pressure
Bed Temp./Furnace Temperature
Fuel Size
Bed Material size & Specifications
Air & Fuel ratio
4. BED HEIGHT/FD AIR PRESSURE
Static height for AFBC Boiler is to be maintained 300
to 325 mm during initial light up of boiler.
Expand bed height for AFBC boiler is to be maintained
500 mmwc to 600 mmwc.
FD Air discharge Pressure 600 to 650 mmwc.
Wind box or Air Box pressure 500 to 600 mmwc.
NOTE: High W.B. pressure increases the erosion
of bed coils & low W.B. stops fluidization.
5. PRIMARY AIR PRESSURE
P.A. fan air header pressure for AFBC boiler is to be
maintained 1000 to 1150 mmwc.
Difference of primary air pressure & F.D. wind box
pressure is to be maintained approximately 500
mmwc.
NOTE: High P.A. pressure increases the bed coil
erosion and carryover to enhance secondary
combustion.
6. BED TEMPERATURE/FURNACE
TEMPERATURE FOR AFBC/CFBC
Depends upon the type of fuel & firing method.
Indian coal 850 to 900 Deg.C.
Imported coal 875 to 925 Deg.C.
Lignite fuel 800 to 850 Deg.C.
Pet coke 875 to 950 Deg.C.
Rice husk and other biomass fuel 850 to 900 Deg.C.
Stoker firing 1100 to 1200 Deg.C.
Pulverized fuel firing 1100 to 1300 Deg.C.
For oil & gas firing 1100 to 1500 Deg.C.
7. FUEL SIZE
When firing with Indian/Imported coal following sizes are
to strictly maintained as it will affect on performance of
boiler.
For AFBC/CFBC Size : 0 to 8 mm
Less than 1 mm not allowed more than 20%.
Distribution: 1 to 5 mm – 70%
5 to 8 mm -20%
0 to 1 mm – 10%
NOTE: Lower the size of coal, higher the unburnt in fly
ash, higher the size of coal, higher the erosion of bed
coils and blockage of fuel air pipe & clinkerization in
boiler.
8. FUEL SIZE CONT’D
For STOKER FIRED BOILERS Size: 5 to 25 mm
Less than 5 mm not allowed more than 5%
Distribution: 5 mm to 15 mm-25%
15 mm to 25 mm-70%
0 mm to 5 mm -5%
NOTE: Lower the size of coal higher unburnt in
flyash & carryover through boiler.
9. FUEL SIZE CONT’D
PULVARIZED FIRED BOILERS
Pulverized coal size: mesh powder
(μm) and, for a bituminous coal
Size Distribution: 2% is +300 micro metre (μm)
70-75% is below 75 microns
20% is about 75-100 microns
NOTE: Higher the size of pulverized coal below 100 mesh
results unburnt in bottom ash.
10. BED MATERIAL SIZE &
SPECIFICATION
Bed Material Size: 0.85 mm to 2.36 mm
Distribution : 0.85 mm to 1.00 mm – 10%
1.00 mm to 1.50 mm - 50%
1.5 mm to 2.36 mm - 40 %
11. BED MATERIAL SIZE &
SPECIFICATION CONT’D
Bed Material Specifications:
Crushed fire bricks castables IS8 grade bricks or river
silica sand
Fusion Temp. 1300 Deg.C Shape: Spherical Angular
Bulk Density 1050 Kg/M3 Silica : 65%
Al2O3 28% Fe2O3: 1.05%
PbO2 1.67 % MnO : Trace
MgO 0.23 % P2O5 : 0.08 %
V2O 0.22 % K2O : 0.45 %
12. AIR TO FUEL RATIO
Theoretical Air for combustion:
Theoretical Air Required:
4.31(8/3C+8(H-O/8)+S) Kg/Kg of fuel burnt.
To Understand the basics of efficient boiler Operation, the
combustion process must be understood. Stable combustion
condition requires the right amount of fuels and Oxygen,
combustion products are heat energy,CO2,water vapour,
N2,Sox,Nox and O2. In theory there is a specific amount of
O2 needed to completely burn a given amount of fuel. In
practice , burning conditions are never ideal, Therefore excess
air must be supplied to burn the fuel completely depending
upon the type of fuel.
13. TYPICAL EXCESS AIR TO ACHIEVE HIGHEST
EFFICIENCY FOR DIFFERENT FUELS
Captive Power plant(Coal) boilers normally run about
15 to 20 %.
Fuel oil fired boilers may run as low as 5 to 10 %.
Natural gas fired boilers may run as low 5 to 8%.
Pulverized coal fired boilers may run about 10 to 15%.
14. OXYGEN AT BOILER OUTLET
To Ensure complete combustion of the fuel used,
combustion chambers are supplied with excess air.
Excess air increase the amount of oxygen and the
probability of combustion of all fuels.
EA= (O2% /21- O2% )x100
Stoichiometric Combustion
fuel + Oxygen in the air are in perfect balance-.
CO2% or O2% in flue gas is an important indication
of the combustion efficiency.
15. BOILER EMERGENCIES
Various Emergencies situations during Operation with
a special emphasis on the safety aspect like boiler
protection systems controls and interlocks.
Drum level low and low-low.
Drum level high and high-high.
Furnace draught high and high-high.
Bed Temp. high.
Bed Temp low.
Water wall/screen tube/Evaporator tube failure.
17. DRUM LEVEL LOW AND LOW-LOW
(A) CAUSES:
Failure of BFP.
Failure of drum level controllers.
Excess opening of CBD/IBD.
Sudden change in load(sudden red’n in load)
Water tube failure
(B) EFFECT:
Boiler pressure parts may damage badly.
(C) ACTIONS:
Run the boiler if drum level is within safe limit otherwise
allow boiler to trip when the water level goes low-low limit
to protect the boiler pressure parts.
18. DRUM LEVEL HIGH AND HIGH HIGH
(A) CAUSES:
Failure of drum level controller.
Sudden increase in load.
Sudden increase in firing rate.
(B) EFFECT:
Water may enter in to the turbine and serious damage of turbine blades and
thrust pads.
Carry over in Super heater and sharp fall in S.H. temp.
Flange gasket may be failure.
(C) ACTIONS:
Run the boiler if drum level within safe limit and control the FCV.
Open the CBD to maintain drum level in safe limit.
Open the TG side main steam & Turbine drains to avoid the water entering into
TG.
Trip the TG when steam temp gets below the safe limit.
19. FURNACE DRAUGHT HIGH AND
HIGH HIGH
(A) CAUSE:
Due to faulty operation of fan control.
Disturbed combustion .
Uncontrolled fuel entry.
(B) EFFECT:
Boiler may damage due to high furnace pressure.
Weak part of furnace(ducting & Enclosure)may explode high
furnace pressure.
(C) ACTION:
If it is due to faulty operation of ID/FD/PA/SA fan control , take
it on manual mode and maintain furnace in suction.
If furnace pressure has increased beyond limit allow boiler to
trip on furnace draught high-high.
20. BED TEMP. HIGH
(A) CAUSE:
High CV & low ash coal
Low PA/FD/SA flow
Sudden change in load
Ash recirculation system trouble.
Faulty bed thermocouple
(B) EFFECT:
Chances of clinker formation
Chances of refractory failure.
Chances of Screen tube failure.
(C) ACTION:
Control bed temp. by recirculation of ash.
Increased PA & SA flow and reduce the load by cutting coal feeder.
Coal feeder should be trip if bed temp increases beyond 975 deg.c
If bed temp. exceeds further then allow boiler to trip to avoid clinker formation.
Check the bed thermocouple.
21. BED TEMP. LOW
(A) CAUSE:
High PA/FD/SA flow w.r.to load.
Low CV & high Ash content coal used.
Coal feeder trips or overfeeding of coal in to furnace.
Faulty bed thermocouples.
Water /screen/evaporator tube leakage.
(B) EFFECT:
Boiler steam flow reduce.
Super heater temp. drops.
Furnace draught fluctuates.
(C)ACTIONS:
Boiler PA/FD/SA flow reduced if excessive.
Check bed thermocouple.
Stop bed material supply, if running.
Check any leakage sound from furnace.
22. WATER WALL/SCREEN
TUBE/EVAPORATOR TUBE FAILURE
(A) CAUSE:
Starved water wall.
Block tube ,erode tube, pitted tube, salt deposits.
(B) EFFECT:
Hissing steam leakage noise from boilers.
Unstable flame fluctuating draught.
Bed temp. drops sharply.
Increase ID fan loading.
Flue gas outlet temp. decreased.
(ACTIONS):
Take shut down the boiler when boiler tube leakage
noticed and maintain the drum level.
23. SUPER HEATER TUBE FAILURE
(A) CAUSE:
Inadequate steam flow and high gas temp. during hot start-up.
Erosion of tube due to high excess air.
Blocked tube.
Starvation of tube.
Salt deposition due to high water level in drum.
(B) EFFECT:
Hissing noise noticed.
Flue gas temp drops & high FW consumption than steam..
Overloading of ID fan.
(C) ACTIONS:
As soon as leakage noticed start reducing the load and trip the boiler.
Try to locate leakage through manholes before the boiler depressurized.
Boiler is to be forced cooled when S.H. leakage noticed.
24. HIGH SUPER HEATER TEMP.
(A) CAUSE:
High Excess air.
Low feed water temp or HP heater not in service at constant firing
/load.
Sudden increase in firing rate to increase steam pressure.
Inadequate spray water.
(B) EFFECT:
+ve turbine expansion.
Creep rate increase in tube metal ,turbine parts & steam piping.
(C) ACTIONS:
Always keep HP heaters in line when optimum loading of TG.
Slow down firing rate to limit the S.H. Temp.
Reduce excess air if more.
Check Spray control.
25. LOW SUPER HEATER TEMP
(A) CAUSE:
Soot deposit on super heater tube.
Inadequate air flow.
High spray.
Sudden increase in load and pressure drops.
High Drum level.
(B) EFFECT:
Turbine expansion may be –ve.
May induce thermal stresses in S.H.
(C) ACTIONS:
Check air flow, increase, if necessary.
Reduce spray, if more.
Avoid sudden rise in load to boiler pressure drop.
Check feed water temp.
26. FLAME FAILURE
(A) CAUSE:
Dirty Oil/gas burner.
Faulty flame sensor.
Furnace pressure high.
Low combustion Air.
(B) EFFECT:
Boiler will trip on flame failure.
Chances of furnace explosion if unburnt oil/gas/coal moisture entered in furnace.
Steam pressure & temp. may fall.
Variation in drum level.
(ACTIONS):
Purge the boiler putting burner back and purge burner as per cycle time( minimum 5
minutes).
Check the flame sensor & clean the photocell if found dirty.
Check the igniter circuit & H.V. transformer .
Clean the burner tip & nozzles regularly.
Ensure the healthiness of explosion vent & door.
27. FURNACE EXPLOSIONS
(A) CAUSE:
Accumulation of unburnt fuel during lit up /start up of
boiler.
Improper burning.
Inadequate air.
Secondary combustion.
(B) EFFECT:
Furnace explosion can cause extensive damage.
(C) ACTION:
Always purge the boiler with min 40% full load air for
about 5 minutes. No cut short in purging allowed.
Adjust fuel air ratio.
28. BOILER PRESSURE HIGH
(A) CAUSE:
Sudden drop in load/steam flow.
Uncontrolled fuel entry.
Turbine/prime mover trips.
(B) EFFECT:
Disturbance in drum water level.
Safety valve may disturbed if pressure rise in frequent way.
Boiler may trip at high high pressure.
(C) ACTIONS:
Open start up vent to control the pressure.
Control fuel ,air input & drum level.
If TG /prime mover has tripped first, allow boiler to trip but safety valve may
lift.
TG warm up vent put in auto, if pressure exceeds then it will open accordingly.
Use Electromagnetic safety valve to limit the frequent operation of spring
loaded safety valve.
29. PAH/SAH TUBE FAILURE
(A) CAUSE:
Erosion of Air heater tubes.
Corrosion of Air heater tubes.
(B) EFFECT:
Flue gas temp. after APH will fall down.
Increase in O2% in at Air heater I/L.
Air heater completely in line during initial start up.
(C) ACTIONS:
Control flue gas temp. bypasses PAH.
Reduce coal feeding /air to maintain O2%.
If leakages of tubes are more then stop the boiler and plug
that tubes.
30. COAL FEEDER FAILURE
(A) CAUSE:
Electrical supply failed.
VFD faulty.
Bed temp.high.
Furnace draught low.
Drum level low.
(B) EFFECT:
Boiler pressure may fall down.
Steam temp. fall sharply.
Bed temp.will decrease.
Variation in furnace pressure.
Variation in drum level.
(C)ACTION:
Control boiler pressure by reducing the TG load & control S.H. steam temp. by closing
the spray CV.
Reduce PA/SA air to control bed temp.
Control furnace draught & drum level.
Check the electrical fault or emergency stop button.
Check the VFD fault, if any.
Restart the coal feeder after detecting the cause of failure.
31. BOILER FEED PUMP FAILURE
(A) CAUSE:
Motor protection relay operates.
Lube oil temp. high.
Discharge flow less.
Motor bearing temp. high
Deaerator level low.
BFP Suction DP high.
(B) EFFECT:
Stand by pump will start in Auto/manual.
(C)ACTIONS:
Start the stand by pump ,if it does not start on auto ,adjust the load to
maintain the drum.
Analyze and rectify the fault in the main feed pump & put it in auto.
Check the BFP suction strainer & clean it ,if found chocked.
32. LOSS OF FANS
(A)CAUSE:
Electrical motor protection relay operated.
Fan bearing temp. becomes high-high.
Motor bearing temp. becomes very high.
Drive fault.
Boiler trip.
ID fan trips.
SA trip.
(B) EFFECT:
Boiler will trip on.
Furnace draft either low or high.
(C)ACTIONS:
Rectify electrical fault, if any.
Check cause for boiler trip and normalize it.
Check fan/motor bearing RTD.
Restart the fan(ID/FD/SA) after checking the cause of tripping and
taking corrective actions.
33. EXPLOSIVE POWER OF BOILER
It will not be false to state that power librated by the
explosion of Lancashire boiler 7.5’ dia x 30’ length,
working at 7 Kg/CM^2 is sufficient to project it to a
height of 3.29 KMS. Therefore hazards of boiler
explosion may well be imagined.
As a thumb rule, it could be stated that destruction
hazards of 28.3 liters of water at 4.23 Kg/CM2 and
sat.temp in a steam boiler is equivalent to 0.45 Kg of
gun powder.
34. Introduction to furnace explosions
In CFBC Boilers
Many CFBC Boilers have suffered/reported furnace
explosion in the past, Apart from causing severe losses to
the business concerned , the occurrences have shaken the
confidence of CPP professionals , however PF boilers are
more prone to the such type explosions than CFBC boiler
but the Operation philosophy of PF boiler is clearly
understood and established due to history of centuries.
As regards of CFBC boilers, these are completely newer
generation of technology and explosions avoidance
measures are not clearly understood by the operating
Engineers.
35. TYPE OF EXPLOSIONS IN CFBC
BOILERS
Most of the explosions faced in CFBC boilers are dust
explosions caused by small particles of coal in the bed
and in the free board kept under suspension by
fluidizing air fans.
Explosions due to FO/HSD/LDO used in duct burners
and /or load carrying burners has also been reported.
36. DUST EXPLOSIONS
A dust explosions is the rapid combustion of a dust cloud .
In a confined or nearly confined space, the explosions is
characterized by relatively rapid development of pressure
with flame propagation and the evolution of large
quantities of heat(coal) and reaction products. The
required oxygen for this combustion is mostly supplied by
the combustion air.
The condition necessary for a dust explosions is a
simultaneous presence of a dust cloud of proper
concentration in air that will support combustion and
suitable ignition source.(Coal/HSD/LDO/FO).
Minor flue gas explosions are called puffs or blow backs.
37. FIRE TRIANGLE AND EXPLOSION
PENTAGON
There are three necessary elements which must occur simultaneously to cause a fire
FIRE TRIANGLE EXPLOTION PENTAGON
Ignition Source(Coal/LDO/HSD/FO) Coal/LDO/HSD/FO
,Suspension Confinement
Air or Oxygen Heat (Temp.) Air or Oxygen Heat (Temp.)
On the other hand, for an explosions to occur,5 elements Fuel, heat, Oxygen,
Suspension and confinement must occur simultaneously :.
These form the five sides of the explosions pentagon like fire triangle, removing any
ignition source one of these requirements would prevent an explosions.
Remembering the three sides of the fire triangle (Fuel, heat & Oxygen) and five sides of
the explosion pentagon(Fuel, heat, Oxygen, Suspension & Confinement) is important in
preventing fires and explosions at any facility.
By eliminating the possibility of either suspension or confinement , an explosion can not
occur, but a fire may occur. By eliminating the fuel, the heat ,or the Oxygen
requirements , neither a fire nor an explosion can occur.
38. BASIC PHILOSPHY OF EXPLOSIONS
PREVENTION
Basic Principles of avoidance of explosions are:
Fuel should never fed in to the furnace continuously for than 12
seconds when there is no fire and coal should be added in a small
quantity at ignition temp of coal.
Furnace is completely purged of the explosive mixture and then
fired.
Fuel supply should be stopped immediately if fire/flame is not
established and repurging is surely done before restart.
Correct air fuel ratio is to be maintained so that dust
concentration with explosive limits is never achieved.
Explosion doors/vents/bleed valve (IN AFBC) must be perfectly
operational and all protections and interlocks and fan drives
sequence to be check in each shutdown as per OEM
schedule/recommendations.