On-line purification method of hydrochloric acid in the production of potassium sulfate by Mannheim process

Abstract

The invention discloses an on-line purification method for hydrochloric acid in the process of producing potassium sulfate by Mannheim method. The gas from the Mannheim furnace is cooled by a cooler, and then enters a first-stage washing tower, a second-stage washing tower, and a third-stage cooling tower in sequence. The membrane absorption tower and the fourth-stage washing tower are emptied; the washing liquid obtained after washing and absorbing the environmental protection tail gas with deionized water enters the second-stage washing tower and the first-stage washing tower for washing in turn, and finally hydrochloric acid B is obtained, and the hydrochloric acid B enters the distillation tower. Distillation is carried out, the distilled fraction is cooled to obtain food-grade hydrochloric acid, deionized water washes the hydrogen chloride gas in the four-stage washing tower, and enters the three-stage falling film absorption tower to absorb the hydrogen chloride gas, and the distilled gas from the distillation tower enters the third-stage The falling film absorption tower absorbs hydrochloric acid A; the heat required by the distillation tower is provided by the exhaust gas generated by the combustion chamber that provides heat for the Mannheim furnace. The method utilizes the residual heat of the exhaust gas of the combustion chamber to perform on-line distillation and purification on the hydrochloric acid to obtain food-grade hydrochloric acid.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to an on-line purification method of hydrochloric acid in the process of producing potassium sulfate by Mannheim method. Background technique [0002] The production of potassium sulfate by the Mannheim method is to use sulfuric acid and potassium chloride in the Mannheim furnace to react under high temperature conditions to produce potassium sulfate and generate hydrogen chloride. The hydrogen chloride is absorbed by water to produce hydrochloric acid, and the potassium sulfate is cooled. The Mannheim method is by far the most mature and reliable method for producing potassium sulfate with the most stable quality. [0003] However, because the hydrogen chloride gas produced by the Mannheim method contains a small amount of impurities such as water vapor, sulfuric acid gas, potassium sulfate dust, potassium chloride dust, these impurities and hydrogen chloride gas exist ...

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Problems solved by technology

[0003] However, because the Mannheim method produces a small amount of impurities such as water vapor, sulfuric acid gas, potassium sulfate dust, and potassium chloride dust in the hydrogen chloride gas, these impurities and hydrogen chloride gas exist in the form of mist, according to current mature technical methods (such as figure 1 ) after absorption, the hydrochloric acid obtained has high impurity content, low quality, and limited use. The enterprise even needs to pay additional expenses to entrust others to consume and use it, which brings certain economic losses to the enterprise.

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