SIMULTANEOUS HOT DESULFURIZATION AND IMPROVED FILTRATION IN COAL UTILIZATION PROCESSES

ALTHOUGH THIS NATION HAS SOME OF THE GREATEST COAL RESERVES IN THE WORLD, MANY OF THEM WILL REMAIN UNUSABLE UNTIL TECHNOLOGY IS DEVELOPED TO MEET BOTH CLEAN AIR ACT MANDATES AND NEW SOURCE PERFORMANCE STANDARDS (NSPS) FOR PARTICULATE, SULFUR DIOXIDE (SO2), AND NITROUS OXIDE EMISSIONS, EFFECTIVELY AND ECONOMICALLY. RECENT BREAKTHROUGHS IN PARTICULATE CONTROL, SPECIFICALLY CERAMIC FILTRATION TECHNOLOGY, HAVE SHOWN THAT NSPS LIMITS ON PARTICULATES CAN BE ACHIEVED AT HIGH PROCESS TEMPERATURES, THERE BY MINIMIZING THERMAL LOSSES AND SYSTEM COMPLEXITY. EXPERIMENTATION WITH SORBENTS, PARTICULARLY METAL OXIDE SORBENTS, HAS RESULTED IN PROMISING SO2 EMISSIONS LEVEL REDUCTION. MOREOVER, SPENT METAL OXIDES, SUCH AS THOSE GENERATED BY STEEL MANUFACTURING AND SMELTING PROCESSES, HAVE SHOWN PROMISE AS CANDIDATES IN SO2 REMOVAL, ON A MUCH MORE COST EFFECTIVE BASIS. FOR EXAMPLE, PRELIMINARY TESTING USING SPENT IRON OXIDE DUST FROM A STEEL MILL BASIC OXYGEN FURNACE (BOF) HAS SHOWN THAT, IN COMPARISON TO AN EQUIVALENT VOLUME OF A MORE TRADITIONAL SORBENT SUCH AS CALCIUM CARBONATE, BOF DUST CAN REMOVE APPROXIMATELY THREE TIMES AS MUCH SO2 BEFORE EXHAUSTION. BECAUSE THE AFFINITY FOR SO2 IS PROBABLY NOT LIMITED TO SPENT IRON OXIDE DUST, PHASE I WILL PURSUE THE TESTING OF SEVERAL SPENT METAL OXIDES TO DETERMINE WHICH SHOW HIGH AFFINITY FOR SO2 CAPTURE IN A LABORATORY SETTING. THE MOST PROMISING CANDIDATES FROM PHASE I WOULD THEN BE EVALUATED IN THE PHASE II EFFORT TO VERIFY THEIR SORBENT CAPACITY BY USING THERMOGRAVIMETRIC ANALYSIS AND TO DETERMINE THEIR ADDITIONAL CAPABILITY AS HIGH TEMPERATURE FILTER AIDS, AFTER CLASSIFYING TO A SPECIFIC PARTICLE SIZE DISTRIBUTION. ULTIMATELY, WHEN UTILIZED AS A "ONCE-THROUGH" SORBENT IN A COMBINATION WITH CERAMIC FILTRATION TECHNOLOGY, THESE SPENT METAL OXIDES WOULD PROVIDE SO2 REMOVAL AND ENHANCE FILTER PERFORMANCE IN A MOST COST-EFFECTIVE MANNER.