Double-circulation desulfurization device and desulfurization process

Abstract

The invention discloses a double-circulation desulfurization device and a desulfurization process, and relates to the technical field of gas desulfurization. The device comprises a first-stage desulfurization tower, a second-stage desulfurization tower and a chimney which are sequentially communicated, the first-stage desulfurization tower, a first-stage circulating pool and a first circulating pump are sequentially communicated end to end to form first-stage desulfurization liquid circulation; the second-stage desulfurization tower, a second-stage circulating pool and a second circulating pump are sequentially communicated end to end to form second-stage desulfurization liquid circulation; an oxidation fan is communicated with a first-stage circulating pool; a filter pressing liquid outlet of the first-stage circulating pool is communicated with a filter press through a filter pressing pump; a pulping pool is communicated with a secondary circulating pool, and the secondary circulating pool is communicated with the first-stage circulating pool through an overflow pipe. The process comprises the following steps: respectively carrying out desulfurization treatment on sulfur-containing flue gas twice, and keeping the first-stage circulating pool to be weakly acidic to oxidize calcium sulfite slurry. The double-circulation desulfurization device provided by the invention has a good flue gas desulfurization effect, can fully convert the calcium sulfite slurry into gypsum, improves the conversion rate and quality of gypsum, and can effectively reduce the scaling and blocking phenomena of sulfite.

Description

technical field [0001] The invention relates to the technical field of gas desulfurization, in particular to a double-cycle desulfurization device and a desulfurization process. Background technique [0002] The flue gas emitted by coal-fired boilers is sulfur-containing flue gas, which needs to be desulfurized before being discharged. Common desulfurization methods include lime-gypsum method, alkali method and ammonia method. Due to the large output of lime in our country, it is widely used in metallurgy and construction industries, and it is cheap and easy to get. Therefore, in many places, the lime-gypsum method is used for desulfurization treatment. [0003] The main principle of the lime-gypsum method is that lime is dissolved in water to generate calcium hydroxide, and sulfur dioxide is dissolved in water to form sulfurous acid. Sulfurous acid reacts with calcium hydroxide to produce calcium sulphite and water. Calcium sulfite is then oxidized by oxygen to generate...

AI Technical Summary

Problems solved by technology

In a highly alkaline environment, calcium sulfite slurry is difficult to fully oxidize, resulting in low conversion and poor quality of gypsum by-products

On the other hand, when the sulfite content is too high, fouling will occur, which will block the pipeline and make the desulfurization system unable to operate normally

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