Hydrogen Production by Supercritical Water Gasification of Biomass with Homogeneous and Heterogeneous Catalyst

Hui Jin,Ximin Zhang,Liejin Guo,Youjun Lu,Aixia Pei

doi:10.1155/2014/160565

Abstract

Biomass gasification in supercritical water is a clean and efficient way to convert biomass to hydrogen-rich gaseous products. Appropriate catalyst can lower the reaction temperature to guarantee the technological and economic feasibility. This paper selects Ca(OH)2, Na2CO3, K2CO3, NaOH, KOH, LiOH, and ZnCl2as typical homogeneous catalysts and three kinds of Raney-Ni, dolomite, and olivine as typical heterogeneous catalysts. The catalyst effects are investigated in the process of biomass gasification in supercritical water with the temperature of 400°C, pressure of22∼24 MPa, and residence time of 20 min. The experimental results show that Raney-Ni has the best hydrogen selectivity and hydrogen yield. The mixture of NaOH with Raney-Ni was investigated in order to research the synergistic effect of different catalysts. The experimental results show that Raney-Ni and NaOH have a synergistic effect in the biomass gasification in supercritical water.

Highlights

Biomass has the potential to provide the increasing energy demand of the world due to the large world-wide resource potential and the optimistic long-term contribution [1]
This paper will investigate the synergistic effect of homogeneous catalyst and heterogeneous catalyst in supercritical water gasification condition
The sampled gases were analyzed by a Hewlett-Packard model 6890 gas chromatograph (GC) with a thermal conductivity detector

Summary

Introduction

Biomass has the potential to provide the increasing energy demand of the world due to the large world-wide resource potential and the optimistic long-term contribution [1]. Supercritical water gasification has recently received significant attention as a potential alternative to energy conversion method [3,4,5,6]. It has an obvious advantage in converting biomass directly without high energy-consuming drying process to obtain high energy efficiency [7]. Activated carbon gained attention as a potential catalyst for hydrothermal gasification because activated carbon has high activity and does not introduce any pollution to the reaction system. This paper will investigate the synergistic effect of homogeneous catalyst and heterogeneous catalyst in supercritical water gasification condition

Experimental Section

Homogeneous and Heterogeneous Catalyst

Synergistic Effect of Homogeneous and Heterogeneous Catalyst

Findings

Conclusion