Sulfur dioxide flue gas absorption system and method for treating sulfur dioxide flue gas

Abstract

The invention discloses a sulfur dioxide flue gas absorption system and a method for treating sulfur dioxide flue gas. The sulfur dioxide flue gas enters a primary absorption tower from the top of theprimary absorption tower, is sequentially sprayed and absorbed by the primary absorption tower and a secondary absorption tower and then is discharged from the lower portion of the secondary absorption tower. Besides, fresh lime slurry is intermittently fed into a raw slurry tank and overflows into a slurry circulating tank, the lime slurry in the raw slurry tank is pumped into the top of the secondary absorption tower from an external circulating pipeline under the action of a slurry pump to spray and absorb the sulfur dioxide flue gas in the tower, and then the lime slurry automatically flows and returns to the raw slurry tank. The lime slurry in the slurry circulating tank is pumped into the top of the primary absorption tower from the external circulating pipeline under the action ofthe slurry pump to spray and absorb the sulfur dioxide flue gas in the tower, and then the lime slurry automatically flows and returns to the slurry circulating tank. The removal rate of sulfur dioxide can reach 99% or more after treatment of the two absorption towers, absorption stability is good, national environmental protection emission indexes are met, the use rate of refined lime can be increased, usage of the lime is reduced, and cost is saved.

Description

technical field [0001] The invention relates to a sulfur dioxide flue gas absorption system, in particular to a treatment method for sulfur dioxide flue gas produced in the fire antimony smelting process by using the sulfur dioxide flue gas absorption system; it belongs to the field of environmental protection. Background technique [0002] In the industrial production of antimony smelting, antimony sulfide ore is added to coke, iron ore, and limestone to rough-smelt antimony concentrate through blast furnace pyrometallurgy to produce antimony oxygen and noble antimony while producing sulfur dioxide flue gas. With the country's emphasis on environmental protection, sulfur dioxide flue gas must reach 400mg / m 3 the following. However, the existing technology is difficult to meet the emission requirements of sulfur dioxide flue gas, or when meeting the emission requirements of sulfur dioxide flue gas, the cost of investment is high, which is not conducive to the improvement of...

AI Technical Summary

Problems solved by technology

However, the production practice of this traditional sulfur dioxide absorption process shows that the original process has the following problems: ① Tail gas SO 2 Concentration cannot be reached stably

②The utilization rate of fine lime is low

③ Tower cleaning requires a lot of labor, the working environment is poor, and occupational hygiene is difficult to guarantee

The main reason is that it adopts internal circulation absorption, the oxygen content of flue gas is low, SO 2 The reaction between flue gas and lime slurry is insufficient, and the generated calcium sulfite is unstable; in order to reduce the exhaust gas control index, the pH value of the discharged lime slurry can only be increased to a high level, resulting in low lime utilization. If the pH value of lime slurry is too high, it will inevitably increase the consumption of fine lime

The lime slurry is circulated in the tower, and the lime slurry discharged outside is overflow, causing a large amount of lime residue to stay in the desulfurization tower system

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