SASOL'S UNIQUE POSITION IN SYNGAS PRODUCTIONFROM SOUTH AFRICAN COAL SOURCES USING SASOLLURGIFIXED BED DRY BOTTOM GASIFIERS

摘要

Sasol has been operating the Sasol-Lurgi fixed bed coal gasification prcoess for more than fifty years, and withrnninety seven units in operation still remains the world's largest commercial application of this technology. Therncombined operational and engineering expertise vested in Sasol represents a formidable capability in the field ofrncoal and gasification science. Coal is a crucial feedstock for South Africa's unique synfuels and petrcohemicalsrnindustry, and is used by Sasol as a feedstcok to produce synthesis gas (CO and H2) via the Sasol-Lurgi fixedrnbed dry bottom gasification prcoess.rnSouth Africa, as well as many other countries in the world, will for many years to come rely on its abundant coalrnresources for energy and specifically for the production of petrcohemical products. Synthesis gas productionrnthrough gasification is growing at a rate of approximately 10% per annum [1], indicating that gasification isrndefinitely not a dying technology. The Sasol plants lcoated in Secunda and Sasolburg (South Africa) gasify >30rnmillion tons per annum of bituminous coal to synthesis gas, which is converted to fuels and chemicals via thernFischer-Tropsch process. The production of chemicals is currently the dominant application for synthesis gas,rnfollowed by power generation, Fischer-Tropsch synthesis and gaseous fuels.rnSasol-Lurgi gasifiers are extremely robust devices, and coal from sources with widely varying properties (e.g.rnAsh content <10% to as high as 35% or "brown coal" with moisture content of approximately 30%) can berngasified provided that certain operational changes are implemented. Other properties, like high cakingrnpropensity for example, require blending to acceptable levels and /or mechanical modifications. Interpretation ofrncoal characterization data gives an indication of expected gasifier performance and the suitability of a specificrncoal source for Sasol-Lurgi Fixed Bed Gasification prcoess. It is therefore critically important to gain an accuraternand fundamental understanding of the properties and expected behavior of the targeted coal feedstcok in orderrnto (1) prepare a suitable conceptual flow scheme and (2) to maximize the eventual probability of success in anyrnproposed gasification venture and (3) to optimize the operation and profitability of existing plants and (4)rneffectively address the environmental aspects.rnIt is the view of the authors that fixed bed gasification technology has a bright future in the areas mentionedrnabove and that Sasol has a unique role in the future application and commercialization of gasification technologyrnglobally. The unique skills of Sasol could however be complementary to those of other parties who share ourrnview on the future of gasification and related technologies .