Magnesium-calcium based wet method desulphurization system and method for removing sulfur dioxide in flue gas and producing gypsum

Abstract

The invention discloses a magnesium-calcium based wet method desulphurization system, which is used for removing sulfur dioxide in flue gas and producing gypsum. The system provided by the invention comprises a desulphurization reactor (1), a magnesium hydroxide supply pipe (9), an oxidation pool (10), a replacement reactor (16), a separator (20), a filter (22), a sedimentation basin (25) and a liquid returning pot (29). A magnesium based desulphurization agent and a calcium based desulphurization agent are added separately, and the desulphurization reaction is completely realized by the magnesium of excellent performance, and the replacement regeneration reaction for producing gypsum by-products is completely carried out by the calcium base. The desulphurization and the oxidation reaction are carried out in a solution state, and the oxidation and the replacement regeneration reaction are optimized, thereby fouling possibilities of the solid state substances are reduced to the lowest; the quality of the desulphurization byproduct gypsum is improved, and the purity and the regeneration rate of the regenerated magnesium-based substance are improved. The invention also discloses a magnesium-calcium based wet method desulphurization method, which is used for removing sulfur dioxide in flue gas and producing gypsum.

Description

technical field [0001] The invention relates to the technical field of wet flue gas desulfurization, in particular to a magnesium-calcium-based wet desulfurization system and method for removing sulfur dioxide in flue gas and producing gypsum. Background technique [0002] At present, there are mainly two types of desulfurization absorbents used in traditional wet flue gas desulfurization methods. One is magnesium hydroxide (Mg(OH) 2 ) slurry is a desulfurization absorbent, which has the advantages of extremely high desulfurization efficiency, low power consumption for desulfurization operation, reliable operation, simple system, low cost, and easy maintenance. South Korea and Japan have been widely used. However, the by-product magnesium sulfate (MgSO 4 ) solution, which is discharged as waste liquid after treatment, so desulfurization consumes a lot of water, and the removed sulfur dioxide (SO 2 ) contained in the waste liquid was discarded, which brought waste of wate...

AI Technical Summary

Problems solved by technology

[0006] (2) In the prior art, magnesium-based desulfurization absorption and magnesium-calcium replacement are completed in the desulfurization reactor, and calcium sulfite (CaSO 3 ) The slurry of suspended solids has the disadvantages of difficult process control and easy scaling;

[0008] (4) Carry out magnesium-calcium replacement to magnesium sulfate after oxidation with milk of lime in prior art, regenerated magnesium hydroxide, the pH value of its reaction is very high (about 10~11), and the gypsum by-product alkalinity that it produces is too strong, The quality of by-products does not meet the requirements;

[0009] (5) In addition, the lime slurry used in the prior art has not been treated with desanding and purification, so the impurities in the raw materials are not only brought to the by-products, but also increase the size of the magnesium-based solid particles and reduce the separation efficiency. Conducive to the full recycling of magnesium components

Images