CONTROL OF DIOXIN EMISSIONS FROM WASTE FUEL COMBUSTION BY COFIRING WITH COAL

EXPERIMENTAL EVIDENCE INDICATES THAT SULFUR IN COAL SUPPRESSES DIOXIN FORMATION FROM CHLORINE COMPOUNDS DURING COAL COMBUSTION. THEREFORE, COFIRING COAL WITH HIGH CHLORINE, MUNICIPAL REFUSE DERIVED FUELS (RDF) OR PAPER INDUSTRY WASTES SHOULD BE EFFECTIVE IN SUPPRESSING DIOXIN FORMATION FROM THESE FUELS. SINCE SULFUR DIOXIDE (SO2) EMISSIONS MUST ALSO BE CONTROLLED IT ISDESIRABLE TO COMBINE DIOXIN AND SO2 CONTROL IN THE COMBUSTION PROCESS. TESTS IN A COMMERCIAL SCALE SLAGGING COAL COMBUSTOR HAVE SHOWN SUBSTANIAL DIOXIN REDUCTION WHEN FIRING COAL, AND WHENCOFIRING COAL AND RDF. SEPARATELY, HIGH SO2 REDUCTIONS WERE MEASURED WITH SORBENT INJECTION INTHIS SAME COMBUSTOR. THE OBJECTIVE OF THIS PLANNED PHASE I EXPERIMENTAL PROJECT IS TO DETERMINE THE FEASIBILITY OF COMBINING THE DIOXIN AND SO2 CONTROL IN ONE STEP WITH SORBENT INJECTION INTO THE SLAGGING COMBUSTOR. A CHLORINE COMPOUND WILL BE USED AS A SURROGATE FOR THECHLORINE WASTE FUELS. IT WILL BE MIXED WITH COAL AND INJECTED WITH THE SULFUR SORBENT INTO THETHE COMBUSTOR. A SET OF COMBUSTION TESTS WILL BE PERFORMED IN WHICH THE CONCENTRATION OF CHLORINE AND SORBENT, INJECTED WITH THE COAL, WILL BE VARIED. FOR EACH CONDITION, THE DIOXIN CONCENTRATION WILL BE MEASURED IN THE STACK OFTHE BOILER TO WHICH THE COMBUSTOR IS ATTACHED, USING EPA APPROVED METHODS. THE PHASE I TEST OBJECTIVE WILL BE TO ACHIEVE THE SAME DIOXIN REDUCTION IN THE HIGH CHLORINE CASES AS WITH COAL ONLY, AND AT THE SAME TIME ACHEIVE HIGH SO2 REDUCTIONS. IF THE PHASE I TESTS ARE SUCESSFUL, THE PHASE II EFFORT WILL FOCUS ON FULLY CHARACTERIZING THE SIMULTANEOUS DIOXIN AND SO2 CONTROL IN THE COMBUSTOR USING BOTH SURROGATES AND CHLORINE CONTENT WASTE STREAMS.