The first project of Nangong University won the gold medal in the National College Students Chemical Safety Design Competition

Modern Express News Isopropanol production raw material recycling, lower total energy consumption, safer operation, more perfect process...... Recently, the entry of the "Younger Siblings Riding the Wind and Waves" team composed of 6 students from the School of Chemical Engineering and the School of Safety Science and Engineering of Nanjing University of Technology won the gold medal of the 8th National College Students Chemical Safety Design Competition for the process design and safety evaluation of the 60,000 tons of isopropanol project.

According to reports, isopropanol has a wide range of uses in pesticides, electronics industry, medicine, coatings, daily chemicals and organic synthesis, etc., can be used to produce glycerin, isopropyl acetate, isopropyl ammonium salts, etc., can also manufacture pesticides, disinfectants and preservatives.

"Younger brothers and sisters riding the wind and waves" team investigated the production process of 4 kinds of isopropanol such as acrylic indirect water legal, propylene direct water legal, hydrogenation method of acetate and hydrogenation of isopropyl acetate, etc. Due to the serious corrosion of equipment, three wastes, immature processes, and high raw material prices, the team finally chose acetone hydrogenation method, and innovated the use of distillation - steam permeation membrane integrated separation technology.

"The process's total energy consumption is reduced by 63% compared to conventional distillation, providing a solution for efficient and green production of isopropanol." Team member Zhang Yihuan said that while the team project process successfully intercepted and efficiently recycled acetone, the reactor and hydrogen separation membrane system integration technology were adopted, and the mixture of acetone hydrogenation reaction products produced by flash separation could enter the hydrogen separation membrane system, recover 99.9% hydrogen, and be recycled again as a raw material for the production of isopropanol.

After analysis, they found that when the membrane separation equipment was too large or fully opened in the feed valve, the pressure in the reactor increased, which may damage the membrane structure, resulting in material leakage and fire and explosion accidents. After round after round of modifications, the team finally improved the operational safety of the membrane separation equipment by adding pressure control, flow transmission and safety bypass systems.

"Add pressure control in front of the membrane and use a DCS control system to ensure that the feed is a stable belt pressure flow. Increase the flow transmission instrument behind the membrane to monitor the discharge flow and the state of the membrane, when the molecular sieve membrane is damaged, the switch valve in front of the membrane equipment is closed, and the bypass is opened at the same time, the membrane is short-circuited, and the operation of the entire equipment is not affected. Team member Miao Yuxuan introduced.

In addition to proposing improvements to the production equipment, the team also "diagnosed" the whole process such as the safety management system of the production line, put forward suggestions for organizing on-site emergency disposal plans and emergency rescue knowledge training, regular instrument maintenance and operator specification training, etc.

It is reported that the competition started in April 2021, attracting nearly 100 teams to register for the competition, and finally 8 teams such as South China University of Technology, Hunan University and China University of Petroleum (East China) entered the final, and the representative teams of Nanjing University of Technology, Sichuan University and China University of Mining and Technology won the gold award.

Correspondent Wei Wei Wang Guangyao Modern Express + reporter Li Nan