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A potentially attractive flue gas desulfurization method called Limestone Emission Control (LEC) is currently being investigated by Prudich at Ohio University. In this process, beds of 1/8 inch limestone gravel particles absorb sulfur dioxide from flue gas. This forms sulfite and sulfate salts which coat limestone, blinding the surface and limiting utilization to 20%. Favorable economics can be generating when the unreacted portion of the limestone is recovered by mechanical grinding. This project is a wet method for grinding and recovering the spent limestone from the LEC process, utilizing an impeller fluidizer, a new type of slurry processor. It consists of a cylindrical vessel with an impeller at one end. The impeller generates sufficient pressure head to serve as a slurry pump. It combines the operation of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry. The objectives of the first two years were to operate fluidizer in a batch mode to carry grinding experiments, and to determine the removal of the sulfur coatings from the limestone when operating the fluidizer in a continuous mode. The main thrusts of the third year were to complete the grinding data and coordinate the data with reactivity determinationsmore » of the recovered limestone. Direct measurement of power requirements, operation of single impeller fluidizer, grinding of surface deposits and other methods of removing surface deposits have also been investigated along with sorption characteristics of recovered limestone, microscopic examination of the limestone surface, and limestone attrition.« less |
