Low Temperature Ash characteristic of coals Under Gasification Condition

摘要

IntroductionIGCC (integrated gasification combined cycle) is recognized as the 2nd generation power plant technology which can provide higher electric generation efficiency compared to the conventional pulverized coal combustion facility.[1] However, ash components of coal cause the major downtime of power plant during the operation of continuous gasification system[2,3]. The purpose of this study is to investigate deposited low temperature ash characteristic behavior of coal gasifier/combustor DTF (Drop Tube Furnace), in which behavior of coal particle in actual gasification/combustion condition can be simulated experimentally. Four different pulverized coal samples in the range of bituminous and sub-bituminous are injected into DTF under gasification condition. The ash particles are deposited onto sample collector by the impacting and agglomerating actions; deposit samples of ash are collected analyzed. The deposited ash samples characterized using scanning electron microscope with energy dispersive X-ray spectrometer (SEM-EDX) and X-ray diffractometer (XRD)[4]. The four different fly ash samples, near the top and bottom of the fouling layer taken from the deposit probe surface are measured. Both the surface and internal structure of deposited ash were analyzed. All of the ashes sample are comprised mainly of Al, Si component admixtures, Fe component and Mg, Ca are mixed throughout the ash particles. It is confirmed from the result of SEM EDX analysis that the Fe element compounds which have a big adhesiveness draw other compounds or particles. And also, comparing with result of the top and bottom ash analysis can determine the initial deposition acts in relation to alkali and alkaline earth element components.