Japanese Chemists work on new catalysts for gasification of cellulose.

[NNadir]

One approach to converting cellulose, which makes up the bulk of plant matter, into energy has been through the enzymatic digestion of cellulose, followed by fermentation and distillation to make ethanol. This approach has been receiving a lot of attention lately, but I note that the necessary bioreactors are likely to be expensive, both financially and environmentally, especially in the sense of being water and energy intensive.

This approach, should it pan out, is therefore worth a look. These kinds of systems offer a great deal more fuel flexibility potentially.

Introduction

As part of the search for alternatives to fossil fuels, which raise atmospheric CO2 levels when burned, attention is increasingly focusing on the potential of biomass for use as a renewable energy resource. Hydrogen, too, is an ideal clean energy source, since its combustion releases only water and no carbon dioxide. For this purpose, gasification of biomass is a promising method. In biomass gasification, the formation of tar is likely to be unfavorable. Although gasification at high temperatures decreases tar formation, the process requires high energy input that leads to high costs. Moreover, high temperatures may damage the gasification furnace. For these reasons, the process should be operated at low temperature. One of the most promising methods for eliminating tar from the product gas is the catalytic gasification of biomass. Many reports describe the use of catalysts (for example, dolomite); however, carbon deposition on catalysts may cause deactivation.1,2 Tomishige et al. studied the catalytic gasification of cellulose as a model of the conversion of biomass to synthesis gas.3-5 In his study, which used a fluidized bed reactor, they found that Rh catalysts supported on CeO2 or Ce/SiO2 showed high activity for this reaction. Rh/Ce/SiO2 catalysts, in particular, showed catalytic activity for a long period without the formation of tar or char.4,5 Moreover, they reported catalysts to be effective for the gasification of real biomass.6,7

We have investigated hydrogen production by gasification of cellulose over Ni-based catalysts, since Ni has reforming ability and is cheap, and found that Ni/Ce/zeolite catalysts are effective for this reaction.8 We also studied the active site of the Ni catalyst.

The article is from the current issue of Energy and Fuels. The Abstract is here: http://pubs.acs.org/cgi-bin/abstract.cgi/enfuem/2006/20/i02/abs/ef050283m.html

[eppur_se_muova]

1. Oops, too late to rec. Interesting link, though. nt