System and process of triple-effect cross-flow evaporation

Abstract

The invention discloses a system and a process of triple-effect cross-flow evaporation. The system of triple-effect cross-flow evaporation comprises a first effect evaporator, a second effect evaporator, and a third effect evaporator, wherein a steam outlet of the first effect evaporator communicates with a steam inlet of the second effect evaporator, a steam outlet of the second effect evaporator communicates with a steam inlet of the third effect evaporator, a material outlet of the third effect evaporator communicates with a material inlet of the first effect evaporator, and a material outlet of the first effect evaporator communicates with a material inlet of the second effect evaporator. In the process of triple-effect cross-flow evaporation, the steam flows from the first effect evaporator to the second effect evaporator, and further to the third effect evaporator, while the material flows from the third effect evaporator to the first effect evaporator, and further to the secondeffect evaporator. The system and the process of triple-effect cross-flow evaporation provided by the invention can effectively control the material concentration during the evaporation-crystallization process in case the material concentration is too high.

Description

technical field [0001] The invention relates to a multi-effect evaporation system and process, in particular to a three-effect cross-flow evaporation system and process for evaporating and separating by-product sodium sulfate in the production process of methionine. Background technique [0002] A method for preparing methionine includes neutralizing a sodium methionine solution under acidic conditions such as concentrated sulfuric acid, and the solution obtained after sodium methionine is neutralized by sulfuric acid mainly contains methionine and sodium sulfate. According to the solubility characteristics of methionine and sodium sulfate, under the condition of 32.4 ℃ to 120 ℃, the solubility of sodium sulfate decreases with the increase of temperature, while the solubility of methionine increases rapidly with the increase of temperature. Therefore, methionine is crystallized and extracted by gradual cooling and vacuum flash evaporation, and then sodium sulfate is recovere...

AI Technical Summary

Problems solved by technology

If the sodium sulfate solution containing methionine is heated up, evaporated and crystallized in the conventional way of gradually raising the temperature and countercurrent feeding and evaporating, the concentration of the material will be very high when it reaches the last effect evaporator, and excessive sodium sulfate will be precipitated, and the methionine in the solution will also be Some crystals will be precipitated, and they will accumulate near the outlet to block the pipe and separator, which is not conducive to the separation operation, and the excessive precipitation of sodium sulfate will easily cause methionine to be heated and carbonized and deteriorate.

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