"MILD GASIFICATION IN TRANSPORT REACTORS"

THERE HAS BEEN RECENT INTEREST IN THE SMALL SCALE PRODUCTIONOF LIQUIDS FROM COAL BY MILD GASIFICATION WHICH CAN BE INTEGRATED INTO THE CURRENT ENERGY INFRASTRUCTURE. WHILE MOST WORK ON MILD GASIFICATION IS ADDRESSING DENSE PHASE REACTORS OR LARGE PARTICLES, SEVERAL LABORATORIES REPORT THAT FLASH PYROLYSIS USING SMALL PARTICLES IN DISPERSED-PHASE REACTORS PRODUCES A HIGHER YIELD (SOMETIMES TWO TO THREE TIMES HIGHER) THAN FIXED-BED PYROLYSIS. THIS PROJECT PROPOSES THE DEVELOPMENT OF A MILD GASIFICATION PROCESS BASED ON THE CONCEPT OF TRANSPORT OR FAST FLUIDIZED BED REACTORS. THE MILD GASIFICATION TRANSPORT REACTOR WOULDBE COUPLED IN A LOOP TO A SECOND REACTOR WHICH WOULD BE USED FOR COMBUSTION OR GASIFICATION. FOR THE PURPOSE OF MILD GASIFICATION WITH MAXIMUM LIQUIDS PRODUCTION, THE TRANSPORT REACTOR IS IDEAL, HAVING THE FOLLOWING ADVANTAGES:I) VERY RAPID HEATING OF THE COAL FEED BECAUSE OF THE EXTREME AGITATION OF THE SOLIDS; II) SHORT GAS RESIDENCE TIME TO SWEEP THE LIQUIDS IMMEDIATELY OUT OF THE REACTOR, THUS, MINIMIZING SECONDARY REACTIONS TO MAXIMIZE LIQUID YIELDS; III) ADJUSTABLE SOLIDS RESIDENCE TIME TO ALLOW COMPLETE DEVOLATILIZATION AT THE OPTIMUM TEMPERATURE (PROBABLY BETWEEN 600 DEGREES CENTIGRADE AND 750 DEGREES CENTIGRADE); IV) EXTREME TEMPERATURE UNIFORMITY THROUGHOUT THE BED; V) THE ABILITY TO HANDLE CAKING COALS BECAUSE OF THE VIGOROUS MOTION OF THE SOLIDS; AND VI) HIGH PROCESSING CAPACITY IN A SMALL DIAMETER VESSEL. THE PRODUCTS OF THE MILD GASIFICATION TRANSPORT REACTOR WILL BE A HIGHLY REACTIVE CHAR AND A HIGH YIELD OF LIQUIDS. THE CHAR WILL BEGASIFIED OR BURNED IN A SECOND REACTOR. WE PROPOSE TO OPTIMIZE THE REACTOR SYSTEM SO THAT THE HEAVIEST LIQUIDS CANBE USED FOR HIGH VALUE CARBON MATERIALS SUCH AS FIBERS AND GASKETS, AND THE LIGHTER FRACTIONS UPGRADED FOR LIQUID FUELS. IN PHASE I WE WILL EMPLOY THE CONTRACTOR'S EXISTING LABORATORY FACILITIES TO SIMULATE THE CONDITIONS IN A TRANSPORT REACTOR AND IN THIS WAY DETERMINE THE CONDITIONS NEEDED TO OPTIMIZE THE PRODUCT YIELDS AND QUALITIES. WE WILL ALSO EXPLORE PRETREATMENTS OF THE COAL AND EVALUATE ADDITIVES TO THE REACTOR WHICH IMPROVE YIELD AND PRODUCT QUALITIES. ON THE BASIS OF THESE DATA WE WILL EMPLOY THE CONTRACTORS COAL CONVERSION MODEL, FG-DVC AS THE BASIS FOR AN ENGINEERING MODEL OF THE REACTIONS IN THE TRANSPORT REACTOR EMPLOYING LITERATURE INFORMATION ON SOLID AND GAS RESIDENCE TIMES. WE WILL USE THIS ENGINEERING MODEL TO FULLY EVALUATE THE PROCESS CONCEPT AND TO DESIGN A CONTINUOUS FLOW REACTOR TO BE BUILT AND TESTED IN PHASE II.