GASIFICATION PERFORMANCE OF AUSTRALIAN LIGNITES IN A PRESSURIZED FLUIDIZED BED GASIFIER PROCESS DEVELOPMENT UNIT UNDER AIR AND OXYGEN-ENRICHED AIR BLOWN CONDITIONS

摘要

This paper discusses the gasification performance of a number of Australian lignites in a high temperature winkler (HTW) gasification process development unit (PDU) capable of running at a pressure,temperature,and feed rate of 10 bar,1000 deg C,and 250 kg h~(-1) respectively.The fuels include three Victorian lignites,one South Australian lignite,and a char derived from a Victorian lignite.All fuels were pre-dried to less than 20% moisture content.The tests were of 3-32 h duration.The majority of the tests were conducted at 8 bar(g) pressure,125-240 kg h~(-1) feed rate,750-920 deg C average bed temperature,and involved steam and air or steam and oxygen-enriched air as reactants for gasification.Carbon conversion ranged between 70-87%,with further improvement limited by elutriation of carbon-rich fines originating from a large fraction of fine particles present in the feed,and brittle nature of these lignites which generate fines through attrition.An acceptable calorific value of 4 MJ kg~(-1) of the fuel gas has been attained.An assessment of the reasons and the extent of loss of char through elutriation has been investigated through tests in a 1 : 1 scale cold model and characterization of the char.