Experience in the Development and Implementation of Chromium-Alumina Catalysts of the KDI Series for Isobutane Dehydrogenation in a Fluidized Bed

Abstract

The paper summarizes the experience in the development of a microspherical chromium-alumina catalyst for isobutane dehydrogenation to isobutylene according to the technology devised at Yarsintez. The development of commercial catalysts of the KDI series based on a new boehmite support was considered. Interrelations of elemental and phase composition of the catalysts with their performance were established. A new two-step scheme for producing the boehmite support by hydrothermal treatment of the thermal decomposition product of gibbsite agglomerates with a desired size makes it possible to control its phase composition as well as the physico-mechanical characteristics of the catalysts and their catalytic properties, which allowed obtaining a series of KDI, KDI-M, and KDI-M1 catalysts. The most important steps in commercial implementation of the catalyst at PJSC Nizhnekamskneftekhim were noted. The commercial KDI-M catalyst provided a stable 33–37 % yield of isobutylene in isobutane dehydrogenation and a 30 % yield of methylbutenes in isopentane dehydrogenation. The catalyst consumption was 2–3 kg per ton of the produced isobutylene. The catalyst operation was monitored to propose a way for its improvement and optimization of the reactor instrumentation. According to the laboratory testing, a commercial sample of the KDI-M1 catalyst modified with a silicon-containing inorganic complex compound has higher activity and selectivity than previous catalysts of this series and is ready to industrial implementation.