INTENSIFICATION OF GRAVITATIONAL METHOD OF AMMONIAC WATERS PURIFICATION FROM COAL TAR IMPURITIES

Abstract

Ammoniac waters of coke-chemical production, including ammonia-tar liquor and condensate of primary gas coolers (PGC), are made up more than 50% of total effluent of catching chemical products department. Ammoniac waters contain impurities of aromatic tars and oils (coal tar substances) in the number of 300-2200 mg/l. The presence of tars and oils in ammoniac waters complicates their further processing, reduces the effectiveness of technological processes, contaminates equipment with tar deposits. The gravitational method can not provide effective purification of ammoniac waters from fine disperse tar particles which radius is smaller than 20 microns. Therefore, for enlargement of tar phase particles the coalescence was suggested. In earlier works it was proved that mineral fiber material of diabase group (MFD) leads to increased sizes of disperse particles of coal tars and oils, and redistribution of the fraction in the direction of larger particles. The effect of coalescence is 75-78% depending on the temperature, flow rate, packing density of mineral fiber material. It is shown that preliminary processing of ammoniac water by passing it through a coalescing filter intensifies the gravitational settling of coal tar impurities in the settling tanks. Based on theoretical and experimental studies it is suggested to include a coalescing filter on coke-chemical plants technological scheme of ammoniac water purification from coal tar impurities. In the present technological scheme the process of coalescence is auxiliary. However, due to a coalescing filter high efficiency of ammoniac water purification can be provided. Coalescence method can be attributed as a regenerative method, as during the processes tar water emulsion is separated into two phases, one of which is tar. Recycling of tar can be an additional economic achievement in implementation of this method.