Biomass conversion hydrogenation

A variety of chemical and biological reactions involving supercritical fluid technology are being explored and developed. They include polymerization reactions, biomass conversion, hydrogen production, applications of supercritical water oxidation, self-assembly applications, synthesis of specialty chemicals, manufacture of materials with tailored properties, and much more. These developments and new ones are expected to mature and be commercially deployed in years to come. 

This chapter focuses on "biomass to hydrogen conversion technologies." A variety of biomass resources can be converted for energy supply. They can be divided into four general categories 13... 

This review limits itself to the treatment of high-temperature thermochemical biomass conversion technologies. There are very good overviews of biological conversion technologies for hydrogen production, for example, Ni et al.13 and Zaborsky.29... 

Biollaz, S. Sturzenegger, M. Stucki, S., Redox Process for the production of clean hydrogen from biomass. In Progress in Thermochemical Biomass Conversion, Seefeld, Tirol, 2000. 

Figure 3.3 provides the reader with a summary of the leading direct gasification routes of biomass to hydrogen conversion. 

Chaudhari, S.T., Ferdous, D., Dalai, A.K, Bej, S.K, Thring, R.W., and Bakhshi, N.N. (2000). Pyrolysis and Steam Gasification of Westvaco Kraft Lignin for the Production of Hydrogen and Medium Btu Gas, Abstracts Progress in Thermochemical Biomass Conversion, Tyrol, Austria, 17-22 September. 

Biomass combustion devices, 3 686-688 Biomass conversion, for hydrogen production, 73 784... 

In contrast to the operation of vehicles, electricity and heat for stationary applications can be generated by the combustion of solid biomass without upstream biomass conversion to pure hydrogen (or methanol, BTL or DME). The efficiency of the direct use of solid biomass is generally higher. The overall efficiency of a solid-biomass-fuelled heat and power (CHP) plant is typically about 70% to 80% direct combustion of solid biomass (e.g., wood chips, wood pellets) in suitable boilers for heat generation only can reach an efficiency of more than 90%. 

The production of H2 from some by-products of biomass conversion is also a possible option, which also requires the development of, new, more stable, more efficient catalysts that operate directly in the liquid phase. The catalytic production of hydrogen from more valuable products, such as bioethanol, should be reconsidered with appropriate economic assessments that take into account the alternative possible uses of these products. 

Surmen, Y, Demirbas, A. 2002. Thermochemical conversion of residual biomass to hydrogen for Turkey. Energy Sources24 403 11. 

Although carhon dioxide is released in most of the biomass-to-hydrogen conversion processes, the net CO 2 emission is zero due to the photosynthesis of green plants. 

Coproduction (biorefinery) of, for example, phenolic adhesives, polymers, waxes, and other products with hydrogen production from biomass is being discussed in the context of biomass gasification plant designs to improve the overall economics of biomass-to-hydrogen conversion.11 The technical and economic viability of such coproduction plants is unproven and was not considered in this analysis. 

Economic Analysis of Current and Future Biomass-to-Hydrogen Conversion... 

Considering the assumptions for future technology, biomass-to-hydrogen conversion is unlikely to produce hydrogen at a competitive price, even when compared with hydrogen generated from distributed natural gas. 

Biomass-to-hydrogen conversion is a thermodynamically inefficient path for using solar energy. 

Figure 7.1. Stepwise accumulated efficiency of chains of energy conversion from primary sources to end-use, taken here as personal transportation. Current vehicles based on oil products are compared to fuel cell vehicles using methanol from biomass or hydrogen from wind (Sorensen, 2004g see text for details).

Barrio, M., Gabel, B., Risnes, H., Henriksen, U., Hustad, J.E. Sorensen, L.H. (2000) Steam gasification of wood char and the effect of hydrogen inhibition on the chemical kinetics. Proceedings of Progress in Thermochemical Biomass Conversion, 17-22 September 2000, Tyrol, Austria. 

In the Canadian context there need not be a restriction on biomass conversion processes to be self-sufficient and therefore be required to sacrifice carbon to drive the processes, Natural gas and hydro/nuclear electricity are likely to be available on a large scale through to the early decades of the next century. One or all of the following options have been discussed in the context of biomass conversion and in the specific case of methane additions to alter hydrogen to carbon monoxide ratios in syn gas work is presently under way to combine oxygen blown wood gasification with the reforming of natural gas, (5),... 

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