Not long ago, the government issued the “Implementation Plan for Expanding Biofuel Ethanol Production and Promoting the Use of Ethanol-Blended Gasoline for Vehicles,” which calls for the nationwide promotion of ethanol-blended gasoline by 2020, with the goal of achieving near-universal coverage. As soon as the new policy was announced, it sparked a strong reaction in the refining and light hydrocarbons industry, and the C4 utilization sector—which relies primarily on MTBE as its main outlet—faced unprecedented challenges.

On November 18, the C4 Industry Chain Transformation Symposium and the Inaugural Meeting of the C4 Special Committee of the Light Hydrocarbons Utilization Industry Collaboration Group—hosted by the China Chemical Information Center and organized by Kaier Environmental Technology Co., Ltd.—was grandly inaugurated in Beijing. Representatives from the light hydrocarbons sector across the country gathered to engage in lively discussions on topics such as the current status and prospects of fuel ethanol development globally and domestically, challenges faced by refining and petrochemical enterprises under new policies, and the direction of transformation for the C4 industry chain.

Liu Wenfei, Deputy General Manager of our company, presented on indirect alkylation technology and the development and application of catalysts. Drawing on its extensive experience in process technology and resin catalysts, the company began establishing R&D initiatives to develop C4 utilization technologies under the ethanol-blended gasoline policy shortly after the policy was implemented nationwide in 2003. The dimerization of isobutene to isooctene is an ideal route for utilizing isobutene as an alternative to MTBE; isooctane, produced by the hydrogenation of isooctene, is a high-octane gasoline component.

　　The isobutylene coupling technology and catalysts developed by the company for the production of isooctane have completed small-scale, pilot-scale, and industrial-scale testing. This indirect alkylation catalyst has been successfully commercialized in coupling units both domestically and internationally, and the process technology has also achieved successful operation in domestic industrial plants. Liu Wenfei pointed out that the main challenges in the R&D of indirect alkylation catalysts include:

　　— Catalyst selectivity: For downstream C4 deep-processing units, such as 1-butene separation and direct alkylation, all or part of the isobutene must be removed. Furthermore, it is necessary to minimize the participation of n-butene in the isomerization reaction. This requires the resin catalyst to possess high selectivity, increase the isobutene conversion rate, suppress n-butene isomerization, and reduce the n-butene conversion rate.

　　— Catalyst Temperature Resistance: The condensation reaction is prone to sudden temperature spikes, which requires the catalyst to possess high temperature resistance and ensure the stability of functional groups under high-temperature conditions.

　　— Catalyst Lifespan: The cycloaddition reaction tends to produce trimers or polymers, which clog the catalyst’s pores and lead to catalyst deactivation. This requires the cycloaddition catalyst to have a more optimal pore structure and pore size distribution to extend its lifespan.

　　The KC110 series resin catalysts developed by the company underwent long-term stability testing; during stability tests lasting up to 1,000 hours, the reaction conversion rate showed no significant change. In pilot-scale experiments, using a combined olefin coupling process involving pre-reaction followed by catalytic distillation, the total isobutene conversion rate reached over 99.5%, with a selectivity for C8 olefins exceeding 90%; Optimal operating conditions were determined for the catalytic distillation column and the saturated hydrogenation desulfurization reaction; these conditions are similar to those of an MTBE unit. Based on pilot-scale test data, KaiRui Environmental Technology established a technical plan for retrofitting an MTBE unit into an isobutylene polymerization unit. In December 2016, a 130,000-metric-ton isobutylene polymerization unit was completed and put into operation.

　　During the conference, the C4 Subcommittee of the Light Hydrocarbons Utilization Industry Collaboration Group was also established. KaiRui Environmental Protection Technology Co., Ltd. was elected as the chair unit of the subcommittee, and Zhang Yong, General Manager of KaiRui Environmental Protection Technology Co., Ltd., was elected as the subcommittee chair. It is understood that following its establishment, the C4 Subcommittee will be dedicated to guiding the sustainable development of the C4 industry chain, optimizing the industrial development environment, and building a platform and bridge for member enterprises to connect industry, academia, and research, as well as to communicate with relevant government departments.