Gas Generator Research and Development BI-GAS Process. Use of Calcilox as a Solidification Agent in the Settling Pond

摘要

Since initial operations began in August 1976 the handling and disposal of fine solids from the BI-GAS Pilot Plant waste disposal pond has been a problem. The fines produced in the coal grinding operation as well as carry over from the coal and char cyclones have particularly aggravated that problem. The contract with the Indiana Borough Sewage Plant limits the amount of solids, in slurry form, it receives to 520 lbs/day. Therefore, coagulants have been used to separate the suspended fines from the wastewater. Periodically, the pond must be emptied as a result of this practice. An effective means of solids disposal is necessary for extended operation of the BI-GAS Pilot Plant and may be necessary for a commerical design. This report presents the results of a laboratory study evaluating the applicability of using Calcilox to stabilize the soupy consistency of the wastewater pond. Calcilox is a calcuim-based chemical, developed by Dravo Corp., that triggers cementatious type reactions entrapping the refuse particles and water in a consolidated soil-like consistency. The results of the testing program substantiates Dravo's claim; however, the amounts of the solid necessary to do the job were considered excessive. The tests evaluated a 20% and a 35% by weight slurry concentration of fines to which Calcilox, in concentrations up to 50% by weight of the fines, was added. Because the process was enhanced in an alkaline environment, lime concentrations up to 3% by weight of the fines, was also added in certain tests. From an evaluation of the data, it is expected that 30 to 50% Calcilox and 2 to 3% lime addition (by weight of the solids contained), would be necessary to effect reasonable stabilization of an initial 35% slurry. Somewhat greater amounts would be necessary at lower slurry concentrations. (ERA citation 05:012984)