Method and device for denitration, desulfurization and dust removal of FCC tail gas through ammonia process

Abstract

The invention discloses a device and method for denitration, desulfurization and dust removal of an FCC tail gas through an ammonia process. The device comprises a first-stage waste heat recovery system, a denitration system, a dust removal and desulfurization system, a tail gas exhaust system and an ammonium sulfate aftertreatment system, wherein the dust removal and desulfurization system comprises a dust removal tower and an absorption tower which are separately arranged; the tower top and the tower bottom of the absorption tower are connected with the tail gas exhaust system and the ammonium sulfate aftertreatment system; and the absorption tower is sequentially divided into an oxidation segment, an absorption segment and a fine particle control segment from bottom to top. The method for denitration, desulfurization and dust removal of the FCC tail gas through the ammonia process is carried out by adopting the device. According to the method, no wastewater is discharged, secondary pollution is avoided, cooperative control of multiple pollutants is achieved, sulfur dioxide is recovered to obtain an ammonium sulfate finished product, the investment and operation cost can be reduced and long-period stable operation can be achieved.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and in particular relates to a method and a device for denitration, desulfurization and dust removal of FCC tail gas by ammonia method. Background technique [0002] SO 2 , NO x 1. Dust is the main pollutant in the atmosphere and an important pollution source of smog. With the continuous increase of the total amount of industrial pollution and the limitation of environmental tolerance, it is necessary to further improve the emission standards and reduce the concentration of pollutant emissions. FCC exhaust gas has a large content of fine dust (particles with a particle size of 0-10 μm account for more than 50%), SO 2 High concentration (300~4500mg / m 3 ) and other characteristics; at the same time, its dust concentration fluctuates greatly, especially in high-temperature economizer regular "soot blowing" and accident conditions, when the regenerator runs out of agent, the dust ...

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the problem that the existing FCC tail gas ammonia method denitrification, desulfurization and dust removal process can only handle dust concentrations of 30-800mg / Nm 3 The raw material flue gas narrows the selection range of the process, and the quality of the by-product ammonium sulfate product is difficult to guarantee. If the separation process is strengthened, the investment and operation costs will be high; desulfurization and dust removal are carried out at the same time, and the long-term stable operation of the device is difficult, and the running agent Under the circumstances, a large number of catalysts enter the washing liquid to cause the increase of waste residue treatment amount and the defects of catalyst waste. A device and method for denitrification, desulfurization and dust removal of FCC tail gas ammonia method are provided. The device for denitrification, desulfurization and dust removal of FCC tail gas ammonia method of the present invention can run stably for a long time , the by-product ammonium sulfate obtained by the FCC tail gas ammonia denitrification, desulfurization and dust removal method of the present invention has high quality, high desulfurization rate, high denitrification rate, and high dust removal rate, and the net flue gas meets GB31570-2015 "Petroleum Refining Industry Pollutant Emission Standards "Require

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