Abstract:
Objective The aim is to optimize and develop the isobutene selective dimerization technology to form an HD-DIM process for the production of high-purity diisobutylene.
Method Firstly, mixing inert components such as isobutane and/or n-butane into isobutene feed. Secondly, the feed was divided into tube side feed and shell side feed. The former underwent a dimerization reaction in the first reactor tube side and released heat, while the latter absorbed the heat in the shell side and was vaporized before being sent to the reaction distillation tower. Thirdly, using water that forms azeotropes with C4 components and tert butanol was generated by the hydration of this water with isobutene as a composite inhibitor for the reaction section of the reactive distillation tower. Fourthly, the azeotropes drawn off from the reactive distillation tower were used as the recycling inhibitor for the first reactor and second reactor.
Result Firstly, the addition of inert components dilutes the content of isobutene in the feed of the dimerization reactor, effectively reducing the reaction intensity and temperature rise. Secondly, the heat of the reaction was quickly removed to avoid the occurrence of "hot spots" in the reactor, and all the heat of reaction was used for the separation of light and heavy components in the reaction distillation tower. Thirdly, the pipeline and facilities were saved for supplying tert-butanol to the reaction section of the reaction distillation tower in the conventional process, and the consumption of fresh tert-butanol was reduced. Fourthly, the equipment was saved for separating tert-butanol and diisobutylene in the azeotropes and the process was simplified.
Conclusion The HD-DIM process can produce diisobutylene products with a mass fraction greater than or equal to 99.9%, significantly reduce unit energy consumption and increase diisobutylene yield while reducing catalyst loading.