Dual-alkali flue gas desulfurization device and desulfurization method

Abstract

The invention relates to a dual-alkali flue gas desulfurization device and a desulfurization method. The dual-alkali flue gas desulfurization device comprises an absorption tower, a liquid alkali storage tank and a quick lime powder cabin, wherein the quick lime powder cabin is communicated with a lime slurry tank, an oxidation recovery tank, a primary sedimentation tank, a secondary sedimentation tank and a circulating tank in turn; the bottom of the absorption tower is provided with pipes leading to the oxidation recovery tank, the secondary sedimentation tank and the circulating tank; and an absorption tower circulating pump leading to the upper part of the absorption tower is arranged in the circulating tank. The desulfurization process comprises the following steps of: pumping NaOH solution into the absorption tower by using a pump to fully contact a flue gas so as to ensure that sulfur dioxide reacts with NaOH to produce NaHSO3 solution; discharging the NaHSO3 solution into the oxidation recovery tank from the absorption tower; simultaneously, adding Ca(OH)2 slurry into the oxidation recovery tank to produce the calcium sulfite precipitate; and producing a CaSO4 sediment through an oxidation effect of the air provided by an oxidation blower. The device and the method have the advantages of completely eliminating the possibility of fouling and blocking in the tower, having high desulfurization efficiency and low operating cost and preventing huge waste of a desulfurizing agent.

Description

(1) Technical field [0001] The invention relates to a double-alkali flue gas desulfurization device and a desulfurization method, belonging to the technical field of atmospheric environment protection. (2) Background technology [0002] At present, the large-scale boiler equipment desulfurization project of my country's coal-fired power plants has been basically completed, and most professional desulfurization companies turn their attention to flue gas desulfurization of small and medium-sized units. The desulfurization process of small and medium-sized units is also developing continuously. The dual-alkali desulfurization process occupies a large proportion in the market due to its advantages of high desulfurization efficiency and low operating cost. [0003] However, through the follow-up investigation of the dual-alkali desulfurization projects in recent years, it is found that after long-term operation, the dual-alkali desulfurization process generally has the shortcomin...

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Problems solved by technology

[0003] However, through the follow-up investigation of the dual-alkali desulfurization projects in recent years, it is found that after long-term operation, the dual-alkali desulfurization process generally has the shortcomings of fouling in the absorption tower and unsuccessful regeneration of sodium sulfite. Increasing the input of sodium hydroxide will greatly increase the cost, and at the same time, the desulfurization efficiency cannot be maintained at a high and stable level due to the unsuccessful regeneration of sodium sulfite

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