Research On HT-L Fine Ash Blending Combustion In Circulating Fluidized Bed Boiler

In the process of producing syngas from HT-L furnace,a large amount of pulverized coal and fine ash produced.At present,the main treatment methods for this kind of ash in coal chemical enterprises are to pile up in the factory area,selling it out to the brick factory or blending in fuel after secondary drying.However,due to the serious leakage and dust in the transportation process,the environmental problems and the waste of resources are caused,which drew much attention from the society.Therefore,the method of mixing gasified fine ash in circulating fluidized bed boiler is put forward in this work through comprehensive research and analysis.The quantity of heat(dry base)of the HT-L gasifier ash is about 6000 kcal/kg,the water content of wet ash is less than 50% through the vacuum filter.1kg of wet ash produces 2000 kcal of heat,equivalent to 0.285 kg of standard coal.The whole process of fine ash mixing in HT-L furnace is continuous,the stable production process is synchronous with the main process,and the dust from HT-L furnace is spraying treated with water,then add into the ash tank,feed it into the vacuum filter through mud pump,till its water content falls within 50%.The ash water is collected through the filtrate pipeline,and then filtered.The filtered ash is sent to the intermediate storage bin through belt conveyor.The ash is put into the inlet of the ash pump by the feeding equipment arranged in the lower part of the storage bin,and the ash pump is driven by high pressure oil provided by the power package to reciprocate.The ash is pressurized and fed into the dense phase area of the boiler by boiler feeder.The fine ash conveying system was adopted for long distance transportation to the boiler,making full use of the characteristics of flexible space arrangement,long pipeline transportation distance and small capital construction investment.It saves the cost of ash treatment.The ash is closed in the pipeline,and the dust is eliminated after the fine ash is dried.The problem of environmental pollution during the process of transporting the fine ash is solved.The reliability of conveying ash is ensured,environment of the plant improved and clean production realized.The fine ash blending fuel system of HT-L gasifier runs reliably and stably,and improves the level of safety in production.Not only saves the cost of production,but also improves the production level of safety and civilization.It not only realizes utilization of the fine ash of the HT-L without pollution,but also saves the boiler coal at 860 t/h,improving the economic benefit of the enterprise by 3.1 million yuan/a.