A device for removing sulfur trioxide before the air preheater

Abstract

The invention discloses a device for desorbing sulfur trioxide in the front of an air preheater. The device comprises a plurality of groups of alkali injection units and flue gas mixing units which are arranged in a one-to-one correspondence manner; each alkali injection unit comprises an alkali pool, a pump and an atomizing spray nozzle which are sequentially connected; an alkali absorbing agent is stored in each alkali pool; the atomizing spray nozzles are arranged in a front flue of the air preheater; each flue gas mixing unit comprises a substrate flat plate and fins; each substrate flat plate is arranged on the downstream of the corresponding atomizing spray nozzle in the front flue and is arranged along the direction of mainstream flue gas; the fins are arranged on two sides of the substrate flat plate at intervals. According to the device disclosed by the invention, the alkali injection units are arranged in the front flue of the air preheater and spray the alkali absorbing agents in flue gas; turbulence mixing is performed by using the flue gas mixing units; the sulfur trioxide is desorbed by using the strong alkali characteristic of the alkali absorbing agents, and the desorption rate can reach 80 percent or above; by adjusting the atomizing spray nozzles and the flue gas mixing units, the mixing uniformity of the flue gas and the absorbing agent is guaranteed, the length of a reaction zone is shortened, and the service life of a heat storage element of the air preheater is prolonged.

Description

Technical field [0001] The invention belongs to the field of air pollutant treatment, relates to the removal of sulfur trioxide, and is specifically a device for removing sulfur trioxide in front of an air pre-heater. Background technique [0002] Thermal power stations widely use coal as a fuel to generate electricity. Coal contains sulfur, and most of it is converted into sulfur dioxide and sulfur trioxide after combustion. For units installed with SCR denitration system, the SCR catalyst catalyzes the reaction of nitrogen oxides and ammonia to generate nitrogen, and also catalyzes the conversion of sulfur dioxide to sulfur trioxide. Compared with units without SCR denitration system, the SCR denitration system is installed. The concentration of sulfur trioxide in front of the air preheater has nearly doubled. [0003] The sulfur trioxide in the flue gas can easily form sulfuric acid with water. Low-temperature corrosion caused by sulfuric acid is extremely harmful to the heat...

AI Technical Summary

Problems solved by technology

This invention uses thiosulfate and chloride salt to absorb sulfur trioxide and sulfuric acid in the flue gas, but this invention does not use a proper intensified mixing device, which is not conducive to the reaction between the absorbent and sulfur trioxide, and the concentration of sulfur trioxide is relatively high When the reaction area may extend into the air preheater, corrode and block the air preheater

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