Performance Enhancement of Steam Methane Reforming Using Tubular Packed-Bed Microreactors and Dilution by Adsorbent

Abstract

For an endothermic reaction such as steam methane reforming (SMR), temperature gradients in the packed bed can play a significant role in process performance. A reactor design strategy that considers the combination of tubular packed-bed microreactor (TPBM) operation and catalyst dilution by adsorbent is proposed for enhancement of the SMR process. Simulation studies have been performed with the proposed strategy to quantitatively study the effect of heat transfer limitation and process performance in terms of methane conversion and hydrogen purity. This is carried out using a dynamic 2D pseudohomogeneous model incorporating kinetic and reactor/reaction mechanisms describing the process. The results of these studies show that the temperature gradient in TPBM is better controlled with less catalyst loading in comparison with traditionally used larger diameter reactors. It is seen that improved heat transfer characteristics of the TPBM combined with the effects of catalyst dilution and adsorption complement each other, and enhanced performance in terms of methane conversion and hydrogen purity is observed. The findings based on this study give an insight into the performance improvement of the SMR process and show that cost reduction and process miniaturization of fuel processors for fuel cell applications are possible.

Alumina foam catalyst supports for industrial steam reforming processes

“…In addition to the higher porosity and tortuosity of foams over pellets, barrels and other catalyst supports, graded catalytic beds have been successfully used to increase the control of the temperature for heat limited processes (highly endothermic or exothermic) in industrial reactors. [32][33][34][35][36][37] Various temperature profiles can be obtained by diluting the catalytic bed with inert materials. 32 It is therefore also established that the dilution with inert material can affect the conversion rate of the reaction.…”

Process intensification aspects for steam methane reforming: An overview

“…Therefore, it is desirable to have compact reactors for efficient operations. Rajashree et al 111 proposed the concept of tubular packed bed microreactors (TPBM) with catalyst dilution by adsorbent (for sorption enhancement) strategy for SMR. In this configuration, the heat transfer characteristics of the TPBM and the catalyst dilution strategy compliment each other increasing CH 4 conversion and H 2 yield.…”

The effect of adsorbent characteristics on the performance of a continuous sorption-enhanced steam methane reforming process

“…The sorption-enhanced reaction process (SERP) concept, developed by Air Products and Chemicals Inc. (Hufton et al, 1999), is based on the idea of selective CO 2 removal by adsorption in a fixed bed in order to shift the reaction equilibrium. Several theoretical and experimental studies on this concept have been recently published, investigating different process conditions and/or configurations; see for example Ding and Alpay (2000a); Waldron et al (2001); Ochoa-Fernández et al (2005); Rajasree et al (2006); Johnsen et al (2006). SMR reaction coupled with separation using a membrane reactor has also been proposed (Kim et al, 1999;Abashar et al, 2003).…”