Ionic liquid alkylation

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The alkylation unit with an annual production capacity of 120,000 tons at Shandong Deyang Chemical Co., Ltd. began trial operations at the end of July 2013. If the trials are successful, products such as alkylated oil (industrial isooctane) and n-butane will be available for sale in August. According to previous reports, the alkylation unit at Deyang Chemical uses a new technology based on ionic liquid catalysis for the alkylation of C4 hydrocarbons, making it the first company in China to apply ionic liquid technology in actual production. Currently, institutions such as China University of Petroleum, Peking University, Beijing University of Chemical Technology, the University of Cincinnati in the United States, Southern California University in the United States, the French Institute of Petroleum Research, and Chevron Corporation are all conducting related research, with a focus primarily on chloroaluminate-based ionic liquids. Deyang Chemical uses technology developed by China University of Petroleum; this technology was tested on an industrial scale in Lanzhou Petrochemical’s 65,000 tons per year alkylation plant, but the results were not satisfactory. It turns out that the main reason for the failure was the choice of separator. The catalyst used in the alkylation unit of Lanzhou Petrochemical is sulfuric acid, and the reactor employed is a conventional horizontal propeller-stirred reactor. In the distillation and purification unit, separation is carried out in a sedimentation tank by taking advantage of the difference in specific gravity between the reaction effluent and the sulfuric acid catalyst; however, this approach is not suitable for the alkylation process using ionic liquids. The specific gravity of ionic liquid catalysts is similar to that of the reaction products, so the separation efficiency in the settler is very poor. The ionic liquid is carried to subsequent process units by the reaction products; these subsequent processes include alkali washing and water washing steps. The ionic liquid catalyst solidifies upon contact with water, thereby blocking the pipelines. Therefore, the wrong choice of separator was the main reason for the failure of the industrial scale-up experiment. Subsequently, China University of Petroleum continued to modify and improve ion liquid technology, which is now fully developed. Deyang Chemical uses multiple vertical reactors connected in series, and a suspension separator is employed for complete separation of the ionic liquid from the product, thereby eliminating the risk of the ionic liquid solidifying upon contact with water. In an era of rapid advancement in the deep processing of C4 compounds, alkylation units have replaced aromatization units as the driving force behind such processing. According to Zhuochuang’s statistics, the current production capacity is already approaching 10 million tons. Only Deyang uses ion liquid technology; \"We considered ion liquid technology before investing in the sulfuric acid-based alkylation process, and the main reason we gave it up at that time was catalyst degradation.\" ”A technician from an alkylation unit in Hubei told Zhuochuang. The ion liquid alkylation technology used at China University of Petroleum relies on chloroaluminate-based ion liquids. \"When evaluating ion liquid technology in 2010, the data provided by the laboratory showed that 10 kilograms of catalyst were required to produce 1 ton of alkylated oil, with the price at that time being 60,000 yuan per ton,\" said the technical expert. Chemical engineering technicians from Deyang said that through continuous improvements, the loss of ion liquid catalysts has been significantly reduced, but no specific figures were provided. Deyang Chemical began trial operation with feedstock in late July, showing clear advantages. Firstly, domestic refined oil prices have risen, with the price of alkylation oil increasing by 200 yuan per ton compared to the beginning of the week ； Secondly, by preparing materials in advance, the price of C4 after etherification is relatively lower than it is now ； Furthermore, as manufacturers that started production earlier continue to expand their operations, the acceptance of alkylated oils in the oil blending market is increasing, thereby reducing the pressure on product sales. Shandong Deyang Co., Ltd. was established in March 2011, located in the Dongying Port Economic Development Zone of Dongying City, and was founded with investment from Shandong Zhengshun Wheel Co., Ltd. Investments are currently being made in the construction of a project with an annual production capacity of 100,000 tons of methylal, as well as a project with an annual production capacity of 120,000 tons of alkylated products.