화학공학소재연구정보센터
Reviews in Chemical Engineering, Vol.19, No.6, 531-605, 2003
Recent developments on hydroprocessing reactors
The importance of hydroprocessing has been accelerated due to the imposition of stringent environmental regulations on petroleum products to achieve future goals of sustainability and cleaner environment, and the more demanding situation of middle distillates (mainly transportation fuels) against the availability of heavier and high sulfur crudes. Trickle-bed reactors (TBRs) are mostly used in hydroprocessing. Other types of reactors, such as moving bed reactors and ebullated-bed reactors (EBRs) are also used in the hydroprocessing. All of the above mentioned reactors are operated with cocurrent up or downflow of gas and liquid. TBRs have been most commonly studied over the last 30 years. The design and scale up of TBR is still not well understood, especially with respect to hydrodynamic parameters. Though the EBRs are gaining importance because of their flexibility in dealing with most types of heavy feedstock and the ease with catalyst replacement during operation, there are very limited studies available in literature for the design and scale up of the reactor. Recently, countercurrent operation in a structured catalytic packed bed is gaining importance for hydroprocessing in order to obtain higher conversions. The structured packed column, in which the catalyst particles are enclosed within a wire gauze envelope, is a promising alternative for hydroprocessing. In this paper, an attempt has been made to present the state of art prevailing in structured catalytic packing for the design and scaleup of packed bed reactors operated countercurrently. The performance of the countercurrent catalytic packed bed reactor with different structured packing available in the literature and the conventional TBR with random catalytic packings is also compared. Recommendations have been made for future research in this area.