Ultrapure Hydrogen Production via Dehydrogenation of Heavy Paraffin in a Linear Alkyl Benzenes Plant: Dynamic Modeling Study

Abstract

Nowadays, hydrogen is recognized as a clean fuel with the potential to meet future energy demand and the capability of diminishing reliance on fossil fuels. In the current work, a novel configuration for heavy paraffin dehydrogenation named as radial-flow membrane reactor (RF-MR) is proposed that combines a membrane concept with the radial-flow pattern for both sweep gas and paraffin feed. To provide this configuration, we divided the cross section area of the industrial radial-flow tubular reactor (RF-TR) into some subsections. Moreover, a system for hydrogen production is developed in this reactor based on separating hydrogen from the reaction side through a thin layer of Pd−Ag membrane, covering the gaps wall. Different major operational variables, including inlet molar flow rates of the reaction and permeation side streams, catalyst mass, H 2 /HC molar ratio, and membrane thickness are numerically studied to evaluate the performance of RF-MR. Dynamic modeling results show an average 118.9 ton/day olefin production during 29 d of operation, which is a gain of 28.33% over an RF-TR, using the same catalyst loading and duty. Besides, the ultrapure hydrogen production rate of RF-MR in permeation side is ∼3.21 tons/day.

Computational Design of Pore Structure in Heavy Paraffin Dehydrogenation Catalyst Pellets

“…Dehydrogenation of heavy paraffin is one important approach to produce mono-olefin that can be used to synthesize biodegradable detergents. − An industrial process for heavy paraffin dehydrogenation normally employs a fixed bed reactor packed with catalyst pellets. ,,, The performance of dehydrogenation catalyst directly affects the efficiency of the process for heavy paraffin dehydrogenation. In the industry, the dehydrogenation catalyst is primarily composed of Pt/Al 2 O 3 , which simultaneously catalyzes dehydrogenation of heavy paraffin to mono-olefin, mono-olefin deep dehydrogenation to di-olefin, di-olefin dehydrocyclization to aromatics, and mono-olefin dehydrocyclization to aromatics .…”