阅读说明：本技术 三氯蔗糖附产品氯化铵中回收三氯乙烷的方法 (Method for recovering trichloroethane from ammonium chloride as by-product of sucralose ) 是由 夏家信 钱庆喜 许传久 郑学连 石剑 于 2019-09-30 设计创作，主要内容包括：本发明涉及一种三氯蔗糖附产品氯化铵中回收三氯乙烷的方法,其特征在于包括以下步骤：(1)向溶解釜内投入纯水、半成品氯化铵,在75-85℃、-0.05~-0.1KPa下蒸馏1-2h后投入活性炭,控制纯水：半成品氯化铵:活性炭质量比450:150:1-3,将溶解釜加热至85-90℃,搅拌1.5-2h,过程中回收三氯乙烷形成的冷凝液,冷凝液静置分层得成品三氯乙烷返回系统使用；(2)搅拌结束后将溶解液送入压滤机进行压滤,将压滤后的液体送进降温釜,降温至40℃,随后将溶液送入结晶釜,降温到35℃时,溶液送入离心机离心,即得湿品工业级氯化铵,离心后的母液返回溶解釜使用。本发明的有益效果：解决了生产中产生的固体废渣,产出成品氯化铵产品同时回收三氯乙烷原料,环保、经济。(The invention relates to a method for recovering trichloroethane from ammonium chloride, a sucralose by-product, which is characterized by comprising the following steps of (1) putting pure water and a semi-finished product of ammonium chloride into a dissolving kettle, distilling for 1-2 hours at 75-85 ℃ and-0.05 ~ -0.1KPa, then putting activated carbon, controlling the mass ratio of the pure water to the semi-finished product of ammonium chloride to the activated carbon to be 450:150:1-3, heating the dissolving kettle to 85-90 ℃, stirring for 1.5-2 hours, recovering condensate formed by trichloroethane in the process, standing and layering the condensate to obtain a finished product of trichloroethane to be returned to a system, and (2) sending the dissolved liquid after stirring to a filter press for filter pressing, sending the liquid after filter pressing into a cooling kettle, cooling to 40 ℃, then sending the solution into a crystallization kettle, sending the solution into a centrifuge when the temperature is reduced to 35 ℃, obtaining wet product of industrial ammonium chloride, and returning the centrifuged mother liquor to the dissolving kettle.)

1. A method for recovering trichloroethane from ammonium chloride which is a sucralose by-product comprises the existing steps of dissolving, decoloring, filter pressing and centrifuging, and is characterized by comprising the following steps:

(1) adding pure water into a dissolving kettle, adding a semi-finished product ammonium chloride from a neutralization and pressure filtration working section, distilling at 75-85 ℃ and-0.05 ~ -0.1KPa for 1-2h, adding activated carbon, controlling the mass ratio of the pure water to the semi-finished product ammonium chloride to the activated carbon to be 450:150:1-3, heating the dissolving kettle to 85-90 ℃, stirring for 1.5-2h, recovering condensate formed by negative pressure in the process, and standing and layering the condensate to obtain a finished product trichloroethane which is returned to a system to be used as a raw material;

(2) and after the stirring is finished, sending the dissolved solution into a filter press for filter pressing, removing active carbon and organic impurities, sending the liquid subjected to filter pressing into a cooling kettle, controlling the temperature of the cooling kettle to be 40 ℃, then sending the solution into a crystallization kettle, sending the solution into a centrifuge for centrifugation when the temperature of the crystallization kettle is reduced to 35 ℃, thus obtaining wet industrial ammonium chloride, and returning the centrifuged mother solution to the dissolution kettle for use.

Technical Field

The invention relates to the field of food additive production, in particular to a method for recovering trichloroethane from ammonium chloride which is a sucralose by-product.

Background

Sucralose is used as a novel sweet food additive, has more advantages than sucrose, saccharin, AK sugar, aspartame, stevioside and the like, has high safety and stable performance, is a novel high-quality non-nutritional high-efficiency sweetener, and is an optimal ideal sweet substitute for foods for patients with obesity, cardiovascular diseases and diabetes mellitus; also belongs to the field of fine chemical products, and is a branch product of food additives. It has not only rapidly expanded application range in health food and medicine, but also widely applied to more than 300 processed products such as baked food, beverage, chewing coffee, dairy products, frozen dessert, ice cream, pudding, jelly, jam, syrup and the like, and has been widely accepted by the market at present and becomes one of the most popular high-potency sweeteners.

In the production process of sucralose, the development of the sucralose industry is severely restricted by solid waste residues generated in the neutralization and pressure filtration section. The solid waste generated in the neutralization and filter-pressing working section still contains a large amount of ammonium chloride and trichloroethane, and if the solid waste is directly treated as the solid waste, the raw material cost is greatly increased, and the pressure is also great on the conventional solid waste treatment system of a company; in the existing production, because the solubility of ammonium chloride is very high, the steps of dissolving, decoloring, filtering, centrifuging and the like are used for removing impurities to obtain industrial-grade ammonium chloride, but trichloroethane distilled in the process of treating the ammonium chloride can generate odor, and the environment is easily polluted if the ammonium chloride is not properly treated.

Disclosure of Invention

The invention aims to solve the problems and provides a method for recovering trichloroethane from ammonium chloride which is a sucralose by-product.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for recovering trichloroethane from ammonium chloride which is a sucralose by-product comprises the existing steps of dissolving, decoloring, filter pressing and centrifuging, and is characterized by comprising the following steps:

(1) adding pure water into a dissolving kettle, then adding a semi-finished product ammonium chloride from a neutralization and pressure filtration working section, distilling at 75-85 ℃ and-0.05 ~ -0.1KPa for 1-2h, then adding activated carbon, controlling the mass ratio of the pure water to the semi-finished product ammonium chloride to the activated carbon to be 450:150:1-3, heating the dissolving kettle to 85-90 ℃, stirring for 1.5-2h, recovering formed condensate under negative pressure in the process, and standing and layering the condensate to obtain a finished product trichloroethane (the water content is less than 500PPM, and the trichloroethane is more than 99 percent) which is returned to a system to be used as a raw material;

(2) and after the stirring is finished, sending the dissolved solution into a filter press for filter pressing, removing active carbon and organic impurities, sending the liquid subjected to filter pressing into a cooling kettle, controlling the temperature of the cooling kettle to be 40 ℃, then sending the solution into a crystallization kettle, sending the solution into a centrifuge for centrifugation when the temperature of the crystallization kettle is reduced to 35 ℃, thus obtaining wet industrial ammonium chloride, and returning the centrifuged mother solution to the dissolution kettle for use.

The invention has the beneficial effects that: the recovery process solves the solid waste residue generated in the production, produces the finished product ammonium chloride product, and recovers the trichloroethane raw material, thereby having great environmental protection benefit and economic benefit; about 90L of mother liquor can be recovered from each kettle according to the feeding of the mother liquor, 18 kettles can be fed each day, and 90 x 18 x 300=486000L is calculated according to 300 days of effective production each year; according to the density of trichloroethane of 1.46 g/L; the price is 5000 yuan/ton, and the economic benefit is 486000/1000 x 1.46 x 5000=3547800 yuan per year.

Drawings

FIG. 1 is a schematic diagram of a process for recovering trichloroethane from ammonium chloride, a by-product of sucralose.

Detailed Description

With reference to fig. 1, a method for recovering trichloroethane from ammonium chloride, which is an accessory product of sucralose, comprises the following specific implementation steps: