AN ADVANCED CATALYTIC LOW-RANK COAL GASIFICATION PROCESS FORPRODUCTION OF SYNTHESIS GAS

AN ESSENTIAL FEATURE OF THE STATE-OF-THE-ART COAL GASIFICATION PROCESSES IS THE USE OF PARTIAL OXIDATION OR AUTOTHERMAL REACTIONS. IN AUTOTHERMAL GASIFICATION PROCESSES, STEAM AND SUBSTOICHIOMETRIC OXYGEN OR AIR IS REACTED WITH COAL. THE HEAT FROM THE PARTIAL OXIDATION SUBSIDIZES ENDOTHERMIC GASIFICATION REACTIONS. WHEN AIR IS USED AS A SOURCE OF OXIDANT, THE QUALITY OF THE PRODUCT GAS DUE TO DILUENTS SUCH AS CO2 AND/OR N2 REDUCES THE PRODUCT GAS QUALITY AND INCREASES THE VOLUME OF GAS THAT MUST BE CLEANED AND PROCESSED. WHEN OXYGEN IS USED, REQUIREMENTS FOR AIR SEPARATION FACILITIES SIGNIFICANTLY INCREASES THE CAPITAL AND OPERATING COSTS. IN THE MTCI INDIRECT GASIFICATION PROCESS, THE HEAT FOR THE ENDOTHERMIC GASIFICATION REACTION IS PROVIDED THROUGH A HEAT EXCHANGER. SINCE THE PRODUCT GAS DOES NOT MIX WITH THE COMBUSTION FLUE,THE PRODUCT GAS IS OF HIGH QUALITY CONTAINING ESSENTIALLY COAND H2. THIS SYNTHESIS GAS IS IDEAL FOR USE WITH "INDIRECT LIQUEFACTION" PROCESSES OR AS A SOURCE OF CHEMICAL FEEDSTOCK. THE MTCI PROCESS OVERCOMES THE PRESENT LIMITATIONS OF INDIRECT GASIFICATION PROCESSES, REDUCING REQUIREMENTS FOR LARGE HEAT TRANSFER AREAS AND/OR LOW THROUGHPUT CAPACITY DUE TO LOW HEAT TRANSFER RATES IN CONVENTIONAL STATE-OF-THE-ART HEAT EXCHANGE TECHNOLOGY. THIS PROJECT ADDRESSES THE USE OF A FLUIDIZED BED CAPABLE OFACHIEVING RAPID INDIRECT HEATING WITH HIGH HEAT TRANSFER RATES TO DEVELOP A PROCESS FOR PRODUCING SYNTHESIS GAS FROM LOW-RANK COALS. THE PROPOSED TECHNOLOGY PROVIDES A SIMPLIFIED PROCESS AND REACTOR DESIGN FOR PROCESSING THE UNDERUTILIZED AND INEXPENSIVE LOW-RANK COAL RESOURCE INTO HIGH-QUALITY GAS, WITH HIGH SYSTEM THROUGHPUT AND SUPERIOR OVERALL ECONOMICS.