Thread Content
I was the first to develop the DMC/EG green process. Author/Source: China Chemical Industry News. Date: December 26, 2018. Clicks: 24. On December 21, the green process for converting carbon dioxide into dimethyl carbonate/ethylene glycol (DMC/EG) using immobilized ionic liquids was approved as a scientific and technological achievement by the China Petroleum and Chemical Industry Federation in Yangzhou, Jiangsu. The evaluation committee, composed of academicians He Mingyuan, Fei Weiyang, and Han Buxing from the Chinese Academy of Sciences, unanimously agreed that this technological achievement is a world first. It opens up new avenues for the utilization of carbon dioxide as a resource, energy savings in existing ethylene glycol production processes, and the expansion of the epoxy ethane industry chain. They recommended strengthening international patent applications and promoting its industrial application. This technological achievement was developed through a collaboration between the Institute of Process Engineering of the Chinese Academy of Sciences and Jiangsu Aoke Chemical Co., Ltd. Zhang Suojiang, an academician of the Chinese Academy of Sciences and director of the Institute of Process Engineering at the same academy, explained that this technological achievement has developed a green process for converting carbon dioxide into dimethyl carbonate/ethylene glycol using solid-supported ionic liquids as catalysts. This approach enables atom-economical reactions and a mild conversion of carbon dioxide, thereby overcoming the problems associated with existing processes for producing dimethyl carbonate and ethylene glycol, such as high energy consumption, low efficiency, and difficulties in treating wastewater. According to Zhang Suojiang, this technology uses carbon dioxide waste gas generated from the oxidation of ethylene to produce ethylene oxide as a raw material. Under the action of ionic liquid catalysts, this gas reacts with ethylene oxide through a carbonylation reaction to yield vinyl carbonate, which is then reacted with methanol to produce dimethyl carbonate and ethylene glycol. The main innovations of this technology are as follows: First, an industrially applicable catalyst based on supported ionic liquids was invented and put into mass production, featuring a high one-pass conversion rate for ethylene oxide, strong adaptability to various raw materials, and no need for catalyst separation. Second, key technologies such as uniform gas-liquid distribution in carbonylation reactors were overcome, and a 10,000-ton-scale tubular reactor with three phases – gas, liquid, and solid – using supported ionic liquids was developed innovatively. Third, enhancement techniques for the coupled process of alcoholysis reaction and pressure-swapped azeotropic distillation were researched and developed, enabling optimal integration of the entire system’s heat network. This resulted in significant reduction in energy consumption, improved economic efficiency, lower equipment investment, and the creation of a set of technologies with independent intellectual property rights. According to Zhu Jianmin, chairman of Oak Group, this technology has been put into industrial use. Jiangsu Oak Chemical Co., Ltd. utilized this technology to build a 10,000-ton industrial demonstration plant, and successful operation was achieved with just one batch of feedstock used. The facility was designed by Liaoning Petrochemical Planning and Design Institute Co., Ltd. It has been operating steadily for nearly 5 months now, with all parameters under control; the product quality meets ** as well as industry standards. Link In recent years, market consumption of polyester products in our country has grown rapidly, with demand for ethylene glycol also increasing continuously. In 2017, China’s apparent consumption of ethylene glycol reached 14.4 million tons, while its annual production was only 5.71 million tons, resulting in a high degree of external dependence of 60%. Most of the nearly 20 existing ethylene glycol production units in our country use the direct hydration of ethylene oxide. This process has a high water ratio and high energy consumption, and is facing elimination. China’s annual production capacity for dimethyl carbonate is 730,000 tons, and it is expected to reach 4 million tons by 2020, with a growth rate of 10% per year. Currently, there are over 20 carbonate manufacturers in the country, most of whose production capacity is dedicated to industrial-grade carbonates. All of these manufacturers use the propylene oxide transesterification process; their facilities are small-scale, generate significant pollution, and have low efficiency. There is an urgent need to develop cleaner and more efficient production technologies.