Experience in the Development and Introduction of Aluminochromic for Fluidized-Bed Isobutane Dehydrogenation

Abstract

A summary of experience in the development of a microspherical aluminum–chromium catalyst isobutane dehydrogenation to isobutylene using the Yarsintez technology is presented. The development dynamics of KDI industrial catalysts based on a new boehmite support is considered. The relationships between elemental and phase compositions of catalysts and their operational characteristics are found. A boehmite support was obtained according to a new two-stage scheme, including the hydrothermal treatment of a thermal decomposition product of gibbsite agglomerates with a required size. This technology makes it possible to control the phase composition of a support and the physicomechanical properties of catalysts and their catalytic properties, which made it possible to obtain KDI, KDI-M, and KDI-M1 catalysts. The most important stages of their introduction into commercial operation at Nizhnekamskneftekhim are described. The KDI-M industrial catalyst provides a stable yield of isobutylene of 33–37% during the isobutane dehydrogenation and a yield of methylbutenes of 30% during the isopentane dehydrogenation. The catalyst consumption is 2−3 kg per ton of isobutylene produced. The ways are proposed for the improvement of a catalyst and the optimization of reactor equipment on the basis of monitoring the catalyst operation results. The KDI-M1 industrial catalyst modified with a silicon-containing inorganic complex is better than earlier products of this series in its activity and selectivity according to laboratory tests and is ready for production.