Zhejiang Nhu Company Ltd.

Shandong Nhu Amino Acid Co., Ltd.

Zhejiang University

Cong Chen

Zhirong Chen

Zhixuan Wang

Hong Yin

Zhengjiang Wang

Yin Yan Li

Qichuan Li

Baishan Hu

Guisheng Qiu

Cunchao Wang

Yu Wang

Qingai Shi

Zhixiang Zhang

Shuangshuang Zhang

The present disclosure relates to an additive used in a methionine preparation process, and a methionine preparation method. The additive provided by the present disclosure is a mixture containing components A, B, and C; component A has a structure represented by the following general formula (1); component B has a structure represented by the following general formula (2); component C is silicone oil; RCON(CH)CHCHSONa (1). The methionine preparation method provided in the present invention comprises subjecting methionine to crystallization and/or recrystallization in the presence of the additive provided by the present disclosure. The additive provided by the present disclosure results in uniform emulsification, has good stability, can be used stably for a long time, and is suitable for a continuous crystallization process. The prepared methionine crystal has a good crystal form, a large bulk density, and good flowability. In addition, according to the methionine preparation method of the present disclosure, a crystallization system can operate continuously and stably for a long time without obvious foaming, and the crystallization process of the methionine product can proceed smoothly.

Additive used in methionine preparation process, and methionine preparation method

Provided by the present disclosure are a method and a device for preparing 2-hydroxy-4-methylthiobutyric acid and intermediates thereof; the intermediates for preparing 2-hydroxy-4-methylthiobutyric acid comprise 3-methylthiopropionaldehyde and 2-hydroxy-4-methylthiobutyronitrile. The method for preparing 2-hydroxy-4-methylthiobutyric acid provided by the present disclosure comprises: step (1), a step of reacting acrolein with methyl mercaptan to prepare 3-methylthiopropionaldehyde; step (2), a step of reacting 3-methylthiopropionaldehyde with hydrocyanic acid to prepare 2-hydroxy-4-methylthiobutyronitrile; and step (3), a step of hydrating 2-hydroxy-4-methylthiobutyronitrile by using sulfuric acid and then hydrolyzing to prepare 2-hydroxy-4-methylthiobutyric acid; wherein in steps (1), (2) and (3), the reaction status of the materials is detected online, and the proportions of the materials are controlled according to the detection results such that reactions are performed completely.

Method and device for preparing 2-hydroxy-4-methylthiobutyric acid and intermediates thereof

The present disclosure relates to a method for continuous preparation of high bulk density methionine crystals. The process of the method is as follows: a hydrolysate solution, which is obtained from a reaction of 5-(&#x3b2;-methylmercaptoethyl) hydantoin and a potassium carbonate solution, is mixed with an external circulation material from a DTB neutralization crystallizer having a gas phase neutralization section; after being cooled, the mixture enters a liquid distributor of a neutralization region in the upper part of the crystallizer and is sprayed in the form of liquid droplet or trickle into carbon dioxide gas for neutralization reaction, and then naturally falls into a crystallization region in the lower part to be mixed with a material in the region; the obtained mixture grows on fine crystals in a system to form crystals having larger particle diameters, and meanwhile new crystal nucleuses are formed; in a deposition area in the middle part of the crystallization region, the crystals having larger particle diameters deposits into an elutriation leg, while the fine crystals circulate with the external circulation material, and a part of the external circulation material is used to elutriate the crystals in the elutriation leg, while another part of the same is used to be mixed with the hydrolysate solution; and the crystals in the elutriation leg are separated, washed and dried to obtain the high bulk density methionine product.

Method for continuous preparation of high bulk density methionine crystal

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Weifang, China

Cong Chen