Method and device for synthesizing sodium hydrosulfite

Abstract

The invention provides a process control method of the later period of a sodium hydrosulfite synthetic reaction, aiming at increasing the alcohol and water ratio at the later period of the synthetic reaction and reducing the occurrence probability of a decomposition reaction of sodium hydrosulfite. The method concretely comprises the steps of slowly dissolving solid sodium formate and sodium metabisulfite into a 60-70% methyl alcohol water solution according to the molar ratio of 2: 1; controlling the temperature of a reaction kettle to be 80-85 DEG C, controlling the pressure to be 0.15-0.25Mpa and controlling the pH to be 4.4-5.0; slowly adding liquid sulfur dioxide into the reaction kettle; after the raw material feeding is stopped, slowly adding the mixed solution of sulfur dioxide and methyl alcohol into the raw material; and additionally arranging a set of sulfur dioxide and methyl alcohol matching preparation device on the basis of original production equipment. According to the method and the device provided by the invention, the alcohol and water ratio of a reaction system can be increased, the side reaction is restricted, the purity of the product can be improved to more than 90%, and the safety risk in the production process is reduced.

Description

technical field [0001] The invention relates to a method and a device for synthesizing hydrosulfite, in particular to a process control and synthesis device for late synthesis treatment of hydrosulfite. Background technique [0002] The main raw materials for industrial production are sodium formate, sodium metabisulfite, and liquid sulfur dioxide. The production process is as follows: first dissolve solid sodium formate and sodium metabisulfite in a mixed solvent of methanol and water, and then continuously add liquid SO into the reactor under certain temperature, pressure, pH and other indicators 2 Chemical reaction is carried out to finally synthesize hydrosulfite, followed by solid-liquid separation, washing, and drying to obtain finished hydrosulfite. Its main reaction equation is: 2HCOONa+Na 2 S 2 o 5 +2SO 2 =2Na 2 S 2 o 4 +2CO 2 ↑+H 2 O. [0003] It can be seen from the synthetic chemical reaction equation that methanol does not participate in the reaction ...

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Problems solved by technology

The lower the ratio of alcohol to water, the faster the decomposition reaction. Vigorous decomposition will also lead to explosion and fire accidents in the reactor, which not only affects the content of synthetic hydrosulfite, but also increases the safety risk of production.

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