Biogas Dry Reforming for Hydrogen through Membrane Reactor Utilizing Negative Pressure

Akira Nishimura,Mohan Lal Kolhe,Tomohiro Takada,Satoshi Ohata

doi:10.3390/fuels2020012

Abstract

Biogas, consisting of CH4 and CO2, is a promising energy source and can be converted into H2 by a dry reforming reaction. In this study, a membrane reactor is adopted to promote the performance of biogas dry reforming. The aim of this study is to investigate the effect of pressure of sweep gas on a biogas dry reforming to get H2. The effect of molar ratio of supplied CH4:CO2 and reaction temperature is also investigated. It is observed that the impact of psweep on concentrations of CH4 and CO2 is small irrespective of reaction temperature. The concentrations of H2 and CO increase with an increase in reaction temperature t. The concentration of H2, at the outlet of the reaction chamber, reduces with a decrease in psweep. It is due to an increase in H2 extraction from the reaction chamber to the sweep chamber. The highest concentration of H2 is obtained in the case of the molar ratio of CH4:CO2 = 1:1. The concentration of CO is the highest in the case of the molar ratio of CH4:CO2 = 1.5:1. The highest sweep effect is obtained at reaction temperature of 500 °C and psweep of 0.045 MPa.

Highlights

Division of Mechanical Engineering, Graduate Shool of Engineering, Mie University, Tsu, Abstract: Biogas, consisting of CH4 and CO2, is a promising energy source and can be converted into H2 by a dry reforming reaction
The effect of changing reaction temperature, which means the initial temperature for dry reforming in this study, from 400 ◦ C to 600 ◦ C, and the molar ratio of CH4 :CO2 by 1.5:1, 1:1 and 1:1.5 is investigated
This study has studied the effect of psweep on the performance of biogas dry reforming

Summary

Introduction

Global warming problem is a serious issue in the world. Each country has set the goal to reduce CO2 emission, by 2030 or 2050. A membrane reactor is adopted to improve the efficiency of biogas dry reforming in this study. Since the H2 flux through membrane has increased with transmembrane pressure difference [34], it is expected that the performance of biogas dry reforming has been improved due to the shift of the reaction toward further conversion [31]. Though the impact of negative pressure of sweep gas on H2 diffusion flux has been reported [45], and at this moment, there is no study investigating the effect of negative pressure of sweep gas on the performance of biogas dry reforming. The aim of this study is to understand the effect of pressure of sweep gas (psweep ) on the performance of the biogas dry reforming process. Where Equation (2) is the reverse water gas shift reaction (RWGS), Equation (3) is steam reforming of CH4 and Equation (4) is the methanation reaction

Experimental Set-Up

Performance Evaluation of Proposed Reactor

Results and Discussion

Conclusions