Study On Catalysts And Process For Isobutane Dehydrogenation In Fluidized Beds

With the ever-rising requirement of the environment protection,the application of MTBE is in large amount.Isobutene is the main raw material for the synthesis of MTBE,and can also be used in the production of butyl rubber and polyisobutene, etc.Isobutane inland is over capacity and low availability,so isobutane dehydrogenation can not only increase isobutene production but also improve the availability of isobutane.In this paper, both the catalysts used in the fluidized bed for isobutane dehydrogenation reaction and the corresponding process conditions were studied. The researches on catalysts contained that the preparation, selection and the performance comparison of different catalysts. The effects of regeneration progress on the catalyst performance were also studied. In the aspect of process conditions, there contained the determinations of the optimum temperature and liquid hourly space velocity(LHSV) of reaction and regeneration time. Moreover, the effects of different gas distributors on the reaction were investigated.At first, the process conditions were investigated and then the optimum was identified: reaction temperature 570 oC, LHSV 1.0 h-1, regeneration temperature 500 oC,regeneration time 2 h and air flow rate 2 L/min. The reaction result used pressed stainless steel wire mesh plate as the gas distributor was better than that with stainless steel powder metallurgy sintering plate. By the slurry-spraying granulation and calcination at 800 oC, a series of catalysts were prepared with different chromium content. The stacking density,volume mean diameter and particle size distribution and abrasion radio of these catalysts were measured. The catalytic performances of these catalysts were determined in the fixed fluidized bed reactor and the catalytic performance of YBD-201 which chromium content was 10wt% was best. The specific surface and particle morphology comparisons between YBD-201 and the overseas catalyst A was made by N2-TPD and SEM. The results werethat the specific area of YBD-201 was larger than A, the degree of sphericity of YBD-201 is better than A, and the abrasion radio of YBD-201 was only one fifth of A. In the aspect of the catalytic performance, YBD-201 was superior to A in all aspects, especially activity.Finally, the effects of regeneration process on the performance of YBD-201 have been studied. The TPO, TPR, XRD and TEM were used to characterize YBD-201 after many times regeneration. Both the physical properties and catalytic performance could be recovered after regeneration. According to the above conclusions, the YBD-201 could be used as commercial catalyst for isobutane dehydrogenation reaction in circulating fluidized bed reactor.