Tail-gas comprehensive utilization method in mercuric chloride catalyst

Abstract

The invention discloses a comprehensive utilization method for tail gas in the production of a mercuric chloride catalyst. The method comprises the following steps: the temperature of tail gas coming from a dryer in the production of the mercuric chloride catalyst is between 90 and 105 DEG C; the discharge temperature of the tail gas of which the waste heat is recovered is controlled to be not higher than 45 DEG C through a heat exchange device serially connected with the back of the dryer; the tail gas of which the waste heat is recovered and the tail gas which comes from the other processes in the production of the mercuric chloride catalyst are mixed together, and enters from the lower part of a filler countercurrent gas-washing tower; mixture liquid of BaCl2 and Ba(OH)2 is continuously sprayed down from the top of the filler tower to perform countercurrent gas washing; liquid after washing flows into an anticorrosion circulation tank on the bottom of the tower; washing liquid is continuously circulated and sprayed under the action of a circulating anticorrosion pump; and the tail gas after washing is adsorbed to remove foam through dry activated carbon in an activated-carbon device for adsorbing and removing foam, so as to obtain the tail gas reaching discharge standard. The method can ensure that the tail gas after purification treatment reaches the discharge standard, and both solid waste and liquid waste generated can be directly used for producing the mercuric chloride catalyst, so as to save energy and reduce consumption.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for comprehensively utilizing tail gas. Background technique [0002] Mercury chloride catalyst is a catalyst for the synthesis of vinyl chloride monomer (VCM) by the "calcium carbide-acetylene" method based on coal chemical industry, and is widely used in the polyvinyl chloride industry for acetylene process PVC. In the production process of mercuric chloride catalyst, the tail gas mainly contains 10-2000mg / Nm 3 Mercury chloride and 1-100mg / Nm 3 hydrochloric acid (HCl); when producing regenerated mercuric chloride catalyst, the tail gas also contains 1-50mg / Nm 3 Chlorine gas; tail gas temperature is 90-105°C. For these three harmful pollutants in the exhaust gas, environmental protection requires that they must be purified before they can be discharged. At present, there are mainly two traditional methods for treating tail gas: ① activated carb...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: the exhaust gas after treatment is almost difficult to discharge up to the standard, the activated carbon is replaced frequently, and at the same time, the waste heat of the exhaust gas is wasted

Under normal circumstances, this method is not easy to make the tail gas after purification treatment reach the standard discharge, especially the mercury content in the tail gas. At the same time, the solid waste generated during the purification process cannot be directly used to produce mercuric chloride catalyst. As mercury-containing waste, there is a hidden danger of secondary pollution; the waste heat of the exhaust gas is not recycled, resulting in energy waste