Epichlorohydrin production adds a new green path
On July 29, THE 80,000-ton/year propylene propylene epichlorohydrin (ECH) PROCESS package jointly developed by Shandong KaITai Technology Co., LTD and Dalian Institute of Chemical Physics of Chinese Academy of Sciences passed the expert review organized by China Petroleum and Chemical Industry Federation. The technology package combines the advantages of two ECH processes, hydrogen peroxide oxidation method and glycerol method, and realizes the resource utilization of waste hydrochloric acid through technology coupling, so as to solve the problem that a large amount of by-produced acid seriously restricts the production balance, and improve the economic and environmental benefits of the device. The expert group believes that this process provides a new technical path for the green development of epichlorohydrin products.
According to Meng Fanxin, deputy general manager of Kaitai Technology, hydrogen peroxide oxidation process is an ECH green synthesis process developed by Dalian Chemical Institute. Hydrogen chloride is produced byproduct in the production process of raw material propylene chloride. The glycerol rule is another green technology for ECH production, and hydrogen chloride is needed in the production process. C c method of ECH process is ingeniously with hydrogen peroxide oxidation process in the synthesis of allyl chloride by-product hydrogen chloride as a point of two kinds of process, the whole process in propylene, glycerin (glycerol) as the main raw material, with hydrogen peroxide oxidation method as the core technology, with allyl chloride by-product hydrogen chloride as raw materials for the glycerine method for coupling technology, at the same time of output ECH, To realize the resource utilization of high salt wastewater and waste hydrochloric acid. "Based on this innovation, we developed an 80,000-ton/year epichlorohydrin process package, including a 50,000-ton/year hydrogen peroxide oxidation process and a 30,000-ton/year glycerol process." Meng Fanxin said.
A number of improvements and innovations have been made in the related process technology and key equipment of the C - C process package.
"On the basis of the pilot test results of the 5,000 t/A hydrogen peroxide oxidation process, we have further optimized and engineered it with engineers and technicians, and completed the development of the 50,000 t/a DECH process package." Dalian Institute of compounds Gao Shuang researcher said.
The new ALLyl chloride unit adopts a 25,000-ton/year high temperature chlorination reactor, which improves the production capacity of a single chlorination reactor and reduces the investment cost. The hydrogen peroxide oxidation process adopts two-stage tubular reactor and one-stage tank reactor, which increases the safety of the reaction process and is conducive to the crystallization and separation of the catalyst. The glycerol process reactor adopts mixing reactor without mechanical stirring, which can avoid leakage and reduce power consumption. At the same time, the high-salt wastewater in the propylene and propylene process can be used as raw materials for the production of ionic membrane caustic soda after treatment, and the waste gas and liquid can be incinerated to achieve resource utilization, and the emission reduction and pollution reduction effect is significant.
"The propyl process solves the problem of by-production of large amount of hydrochloric acid from allyl chloride, and realizes recycling of chlorine, sodium and hydrogen. At the same time, it combines the ECH refining process of oxidation method and glycerol method. The crude ECH produced by the two methods can be combined for refining, which reduces the footprint of the plant and further reduces the investment and energy consumption. In addition, the project construction and operation mode of the process is also more flexible, which can be expanded to the hydrogen peroxide plant, caustic soda plant and epoxy resin plant in the upstream of the industrial chain according to the demand, and the production scale of the two processes can be flexibly adjusted according to the raw material supply and market price, so as to maximize the profit." Kaitai technology deputy chief engineer Gao Zhengning said.
According to the reporter, the chloro-alcohol process widely used in ECH production in China has been listed as a restricted process in the Guidance Catalog of Industrial Structure Adjustment (2019) due to its high energy consumption, many by-products and difficulty in treating saline organic wastewater. The ECH technology of direct oxidation synthesis of allyl chloride has been listed as the key core technology of the industry in the "13th Five-Year Plan" to accelerate the organization of research and development. The research and development of propylene and propylene process conforms to the policy requirements and complies with the development trend of energy saving, pollution reduction and carbon reduction in the industry.
Source: Sinochem New network
