Fly ash is captured and removed from the flue gases by economiser, airpreheater and electrostatic precipitator esp located at the outlet of the furnace and before the induced. Bottom ash is handled using hydraulic system, submerged scraper conveyor system and dry bottom ash system. When new power plants were being designed in the 1970s, the state of the art ash handling systems at the time were closed loop water recirculation systems that involved a tank farm thousands of feet away from the boiler. Bottom ash is most often conveyed in a hydraulic system in which the ash is entrained in a highflow, circulating water system and delivered to an ash pond or to dewatering storage bins. The hot ash from the furnace gets quenched as it enters into the water minimizing the clinker. Ash handling system are generally divided into three types fly ash handling system, bottom ash handling system and ash slurry disposal system. The hydraulic bottom ash handling system, utilizing the hydroseal pump, dominated the ash handling industry until the introduction of the jet pump which provided improved performance at a lower cost with reduced maintenance. Wet ash system is can be utilized for bottom ash handling with water impounded hopper and jet pumps for intermittent removal. Bottom ash wtd conversion alternatives presentation prepared for. The fly ash system handles the majorlargest fraction of total ash. The system has to be selected based on many factors like type of boiler, size of boiler, amount of bottom ash generated, method of final handling etc. Very finely sized fly ash often accounts for the major portion of the material conveyed in an ash handling system. One important, but often overlooked factor of an efficient ash handling system, is its compatibility with your facility.
Bottom ash is mostly coarse in nature hence it needs to be further crushed before being transported to ash handling system. Dry bottom ash handling drycon dry bottom ash handling drycon system is a complimentary worldclass product added to the product portfolio of the clyde bergemann power group. Dry bottom ash handling system, bottom ash conveyor. Ash handling system in thermal power plant ash handling. The fly ash gets collected at various points, with most of it in esp hoppers. Bahp, balp and fahp water pumps the pumps shall be of horizontal, centrifugal direct driven type. Coarse ash material such as bottom ash is most often crushed in clinker grinders crushers prior to being transported in the ash conveyor system. They are then sent to the ash pond using a hydro ejector, alternatively, they are sent back to the bottom ash silo to be recycled after going through a submerged drag chain conveyor or dry ash. Wet ash handling systems project engineering division. The receipt, handling and storage of nonhazardous incinerator bottom ash of the types of waste listed in table 2. These supply pumps are used to extract bottom ash from the furnaceeconomizer. The extractor may be a submerged flight conveyor moving belt system or vibrating deck type that moves ash from under the boiler to a crusher where it is fed to a secondary conveyor. Rendition of a ucc nuveyor system for a utility boiler, including gravity.
They are then sent to the ash pond using a hydro ejector, alternatively, they are sent back to the bottom ash silo to be recycled after going through a submerged drag chain conveyor or dry ash extraction conveyor. When a ba handling system deploys jet pumps, the system visavis hp pumps operates sequentially and in onoff mode. An alternative solution to conventional wet bottom ash handling systems is the mac system magaldi ash cooler a fullydry technol ogy, using only ambient air instead of water for bottom ash cooling and handling. These esps and baghouses generally have multiple pyramidal hoppers at the bottom, in which the ash is collected by gravity and then is transferred to a storage silo. Dependent on the quality, quantity and utility of bottom ash, it is absolutely advantageous to adopt a drycon system for dry bottom ash extraction. For projects demanding continuous removal of bottom ash collected at furnace bottom, macawber beekay offers submerged scraper chain conveyor sscc system. Ash storage silos can be constructed for both fly ash and bottom ash applications. As part of our complete environmental technologies line, we continue to provide a variety of ash and material handling solutions, from completely dry bottom ash handling to fly ash and petroleum coke processing. Systems that use impounded hoppers or submerged scrapper conveyors have traditionally handled ash using water as a primary medium. System comprises of water impounded refractory lined bottom ash hopper of adequate capacity with water seal trough and dip plates, allowing free expansion of the. Fly ash and bottom ash are used as a supplementary cementitious or pozzolanic material for cement, concrete and concrete products.
In an industrial context, it has traditionally referred to coal combustion and comprises traces of combustibles embedded in forming clinkers and sticking to hot side walls of a coalburning furnace during its operation. A dry bottom ash handling system is probably more environmentally friendly and economic from a capital cost as well as maintenance cost point of view. May 07, 2014 parts of ash handling system bottom ash handling system coarse ash economizer ash handling system air pre heater ash handling system fly ash handling system ash slurry disposal system 5. Watercooled screws or chain conveyors can be adapted easily for different furnace configurations and for any type of. Water impounded bottom ash hoppers, located under the boiler throat are used to. Dry bottom ash handling drycon system is a worldclass product added to our product portfolio in view of the environmental concerns of conserving water regardless of the quality, quantity and utility of bottom ash, it is absolutely advantageous to adopt a drycon system for bottom ash extraction. Maintenance of ash handling plants and pneumatic conveying. They range in size from 300 cubic feet to 17,500 cubic feet, and are designed to work seamlessly with ash handling systems like the ones we have discussed. Jun 26, 2018 wet ash handling system the free falling ash from boiler furnace is collected and stored in a w shaped water impounded bottom ash hopper provided below boiler furnace for its periodic removal twice in a shift of eight 8 hours per unit. Until a decade ago, removal of bottom ash in a dry state from a large utility size boiler was considered impractical. Large spills of dry product should be removed by a vacuum system. Macawber beekays product profile includes jet pumping system for intermittent removal of bottom ash collected at furnace bottom of pf type boilers. For years, wet bottom ash handling has been the standard for power plants throughout the world. With hundreds of installations worldwide since the 1980s, the mac is the worlds leading dry bottom ash handling system for utility and industrial boilers of any size and burning any.
The design of the ash handling plant is dependent upon the method of ash disposal. Fly ash handling wherever products are burned it is necessary to have an energy efficient ash handling system, especially in a power station environment where large quantities of pulverized fuel ash pfa are created. Bottom ash handling system macawber beekay, bottom ash. Fly ash is the major constituent of the ash generated from pulverized and fluidized bed coalfired boilers. Rendition of a ucc nuveyor system for a utility boiler, including gravity discharge ash pit hopper. Bottom ash water recirculation system complete with dewatering bins, settling tank and surge tank facility. A noticeable other use is as growing medium in horticulture usually after sieving. The material for the bahp bottom ash high pressure, balp bottom ash low pressure and. With options varying from fly ash to bottom ash conveyors, and pneumatic versus mechanical ash handling systems, our experts are ready to. Pressurized pneumatic ash conveying may also be employed. Factors like availability of other resources like water, land etc. Bottom ash handling system bottom ash resulting from the combustion of coal in the boiler falls into the over ground, refractory lined, water impounded.
Bottom ash may be used as raw alternative material, replacing earth or sand or aggregates, for example in road construction and in cement kilns clinker production. Explaining ash handling systems for biomass to energy boilers. Bottom ash conversion options and economics 6 conventional dewatering systems. The m ac system extracts bottom ash in a completely dry way from underneath the boiler and transports it to a temporary. It is also used in soil stabilization and as filler in asphalt and other products that are widely used in construction. The system comprises of dry type bottom ash hopper of adequate capacity with water seal trough and dip plates, allowing free expansion of the furnace without any air ingress. This brochure in the next pages is giving an overview about ewb technical capability and. Dampened material should be removed by mechanical means and recycled or disposed of according t o local and national regulations. Sep 30, 2018 working of ash handling system in thermal power plant. An alternative solution to conventional wet bottom ash handling systems is the mac system magaldi ash cooler a fullydry technol ogy using only ambient air instead of water for bottom ash cooling and handling the m ac system extracts bottom ash in a completely dry way from underneath the boiler and transports it to a temporary. In the united kingdom it is known as furnace bottom ash fba, to distinguish it from.
The final component of a highquality ash handling system is the ash storage silo. Watercooled screws or chain conveyors can be adapted easily for different furnace configurations and for any type of solid fuel being combusted. First of all we will discuss about the dry type bottom ash disposal system. Fly ash vacuum systems are designed to convey free. A university in the northeastern part of north dakota needed to upgrade their central heating system. A dry type system eliminates the water that is used in a conventional wet hopper or submerged chain. One of the methods for handling fly ash is wet system in which the ash is mixed with water to form slurry which is pumped to slurry pit. Coal and ash handling a university reduces maintenance and increases efficiency with a complete coal and ash handling system download pdf challenge. The winters in the region are long and cold requiring a 7 month heating season. Ash handling system in thermal power plant ash handling plant. Such ash can be a considerable environmental nuisance as well as being awkward to handle due to its abrasiveness and hydroscopic. We also delivers aftersales services which include installation, servicing and maintenance of equipments. Quality control programs and certification of bottom ash are in progress to ensure production of a marketable product.
Mac magaldi ash cooler fullydry bottom ash removal system. With the increased use of bottom ash, there is a greater interest in dry cooling and dry removal of ash from the bottom of boilers. A simplified schematic of a hydraulic system is shown in fig. Bottom ash conversion options and economics 3 wet bottom ash ba material handling systems and surface impoundments are presently regarded as the industry standard and are certainly the most commonly used method in the coal fired power industry around the world today. Introductionin thermal power plants the ash handling practicescoal based solid waste are collected as i.
Such ash can be a considerable environmental nuisance as well as being awkward to handle due to its abrasiveness and hydroscopic characteristics. Demech provides variety of systems to handle bottom ash or bed ash generated by the solid fuel fired boilers. Plant client ash handling system each unit capacity year of initial operati on brief description of system 1. The mac magaldi ash cooler is a unique system for dry extraction, air cooling and mechanical handling of bottom ash from pulverized coalfired boilers. Both hp and lp water pumps are used in ba handling system and are discussed briefly next. Fly ash is captured and removed from the flue gases by economiser, airpreheater and electrostatic precipitator esp. The schenck process method of fly ash handling is clean, efficient and fully enclosed, with exceptional reliability and requiring minimum maintenance. The elimination of water from bottom ash handling has many economic. See sections 8 and for additional information on exposure controls and disposal. It may be pumped into a disused quarry or transported from the power. Ash handling pneumatic conveying handling system from schenck.
This is a zero pollution plant for bottom ash removal. Bottom ash handling systemslag and ash falling from the furnace are temporarily stored in the bottom ash silo. With options varying from fly ash to bottom ash conveyors, and pneumatic versus mechanical ash handling systems, our experts are ready to help evaluate which application is best for your plant. The bottom ash quantity is around 20% of the total ash generation and there are mainly two types of bottom ash disposal systems.
Ash handling options for coalfired power plants power. Bottom ash handling system bottom ash resulting from the combustion of coal in the boiler falls into the over ground, refractory lined, water impounded, maintained level, double vsection type w type steel fabricated bottom ash hopper having a hold up volume to store bottom ash and economizer ash of maximum allowable condition with the rate. Wet bottom ash material handling systems and surface impoundments are currently regarded as the industry standard and are the most commonly used method in the coalfired power industry around the. System comprises of water impounded refractory lined bottom ash hopper bah of adequate capacity with water seal trough and dip plates. The ash handling system consists of bottom ash, fly ash conveying systems.
Jul 12, 2012 the schenck process method of fly ash handling is clean, efficient and fully enclosed, with exceptional reliability and requiring minimum maintenance. Bottom ash is part of the noncombustible residue of combustion in a power plant, boiler, furnace or incinerator. Ash collected in economiser, primary air heater and secondary air heater hoppers drops continuously through suitable vertical pipe connections to the flushing connections provided beneath each of the hoppers. Bottom ash handling system, dome valve for pneumatic. A trial operation showed that mixed fly and bottom ash from a coal fued power plant can be. When new power plants were being designed in the 1970s, the state of the art ash handling systems at the time were closed loop water recirculation systems that involved a. In electrical systems and equipment third edition, 1992. Home decorating style 2020 for bottom ash handling system pdf, you can see bottom ash handling system pdf and more pictures for home interior designing 2020 78124 at manuals library. Dry ash collection at coal fired power plants and potential for wte. Ucc develops dry bottom ash conveying withnuveyor pneumatic ash conveying systems, ggyravity dischargg pe ash pit hoppers.