Conversion of biomass

Gross heating value of biomass or methane. Conversion of biomass or methane to another biofuel requires that the process conversion efficiency be used to reduce the potential energy available. These figures do not include additional biomass from dedicated energy plantations. 

U.S. capacity for producing biofuels manufactured by biological or thermal conversion of biomass must be dramatically increased to approach the potential contributions based on biomass availabiUty. For example, an incremental EJ per year of methane requires about 210 times the biological methane production capacity that now exists, and an incremental EJ per year of fuel ethanol requires about 14 times existing ethanol fermentation plant capacity. 

Gasification. Conversion of biomass to gaseous fuels can be accompHshed by several methods only two are used by the biomass energy industry (ca 1992). One is thermal gasification in which LHV gas, ie, producer gas, is produced. The other process is anaerobic digestion, which yields an MHVgas. 

Conversion of Biomass for Fuels. Many predictions for protein uses in the 1970s have already been flilfilled (36). Biomass is being used for fuel, for example (see Fuels frombiomass). Many predictions were again made in 1995 (37). 

Figure 1. Major processes for conversion of biomass for fuel (S)...

Molecular hydrogen plays a major role on the oxidation-reduction processes involved in bacterial energetics, as well as in the degradation and conversion of biomass related with all major elemental cycles. Hydrogenase has a key role on this process and catalyzes the reversible oxidation of dihydrogen, important in bacterial anaerobic metabolism ... 

Figure 30.1 Process options for the catalytic conversion of biomass.

The Marine Biotechnology Institute (MBI) was founded in 1987 for the study and applications of biodiversity in marine environments. Currently, and within the scope of the present book, the research area of relevance is industrial applications of microbiology . The institute also performs research in C02 fixation. The Applied Microbiology Laboratory is searching cost-effective utilization of microbes for environmental conservation and restoration. In particular, the decontamination of areas polluted with petroleum-related compounds has been addressed. Attention has been paid to removal of polycyclic hydrocarbons. They are also developing processing methods for the conversion of biomass and organic wastes by methane fermentation. 

At Brookhaven National Laboratory in the 1980s, a two-step process was described for the coproduction of hydrogen and carbon, with methane being the intermediate see Steinberg.107108 In the first step, carbonaceous material is hydrogasified to methane with a subsequent thermal decomposition of the methane to hydrogen and carbon. In the process, water is also formed from the oxygen present in the fuel. A typical overall conversion of biomass, as reported by Milne et al.,5 would be... 

Diebold J.PThermochemical Conversion of biomass to gasoline, DOE s 11th Biomass Thermochemical Conversion Contractors Meeting, Richland, WA, Sept. 1980 http //www.lib.kth.se/Sammanfattningar/zanzi010607.pdf Klass D. L and Emert G.E., Fuels from Biomass and Wastes, Ann Arbor Science, 1981. 

University of Twente Thermal-Chemical Conversion of Biomass (TCCB)... 

After combining all these equations, the overall conversion of biomass into hydrocarbon or methanol adopts the stoichiometry of Reactions (6) and (7) ... 

Options for Catalysis in the Thermochemical Conversion of Biomass into Fuels... 

Biomass is built-up mainly out of the elements C, H and O, just like many of our current fuels and chemicals, although the C-H-O ratio differs significantly, as will be discussed later. The proof of principle for the conversion of biomass into single components or mixtures that can be blended with fossil fuels or that can replace fossil fuels has been delivered already. Table 6.1 lists fossil fuels that are in use today and their possible biomass derived fuel equivalents. 

Stassen, H.E.M., Prins, W., Van Swaaij, W.P.M., Thermal conversion of biomass into secondary products the case of... 

We may differentiate between direct conversion of biomass into bioenergy (electricity and heat, solid fuels from biogenic wastes and residues, biogas, etc.) and biofuels. Catalysis has a minor role in the first case but is a critical element in the production of biofuels. However, notably, there are also potentially interesting developments related to bioenergy. 

Efficient technology could also be developed based on catalytic biomass pyrolysis for the conversion of biomass into clean and renewable liquid bio-oil. This would facilitate its introduction into the energy market as a renewable fuel or as source of high value chemicals. It is possible to produce stable liquid biofuels from biomass flash pyrolysis, in a single stage catalytic process, although further developments are necessary. 

Development of novel synthetic routes for efficient conversion of biomass derived raw materials with high performance, stability and selectivity, by integrating bio-, chemical and catalytic processes. Synthetic pathways in which the complexity needed in a target molecule is already preformed in the biomolecule are especially favorable. 

The chapters of this book have been selected to provide an introduction to the catalytic issues of biomass conversion processes. The introductory chapters make clear the political decisions, especially in the EU, that drive biomass conversion technology, its prospects compared with other options for renewable energy, and the main technological options for conversion of biomass into secondary energy carriers. 

The Plato (Proving Lasting Advanced Timber Option) process is derived from a technology that was originally developed by Royal Dutch Shell, and was a spin-off from research into the hydrothermal conversion of biomass into liquid fuels. The Plato thermal modification process involves four stages (Figure 8.3) ... 

A biorefinery is a facility that integrates biomass conversion processes and eqtrip-ment to produce fuels, power, and value-added chemicals from biomass. Biorefinery is the co-production of a spectram of bio-based products and energy from biomass. The biorefinery concept is analogous to today s crude oil refinery. Biorefinery is a relatively new term referring to the conversion of biomass feedstock into a host of valuable chemicals and energy with minimal waste and emissions. 

Keywords Packed-bed combustion, thermochemical conversion of biomass, solid-fuel combustion, fuel-bed combustion, grate combustion, biomass combustion, gasification, pyrolysis, drying. 

A new method to analyse the thermochemical conversion of biomass, in the context of packed-bed combustion, is modelled and verified. The sought quantities of the method are the mass flow and stoichiometry of conversion gas, as well as the air factors of the conversion system and the combustion system. 

Very few methods exist to analyse the thermochemical conversion of biomass in the context of PBC. 

This appendix consists of two parts, (a) a conceptual classification and review of the conversion system and (b) a review of conceptual models applied to the heat and mass transport of the thermochemical conversion of biomass. Both these parts are analysed in the context of PBC and the three-step model. Mathematical modelling is outside the scope of this survey. 

The world energy crisis of the 1970s, however, spurred interest once again in ethanol as a transportation fuel source. Brazil adopted the widespread production and use of Alcool, hydrated ethanol, and Gasolina a 78 22 ratio blend of gasoline ethanol as a motor fuel. Other countries developed policies to maintain a fuel grade ethanol industry by conversion of biomass. Also, clean air and reformulated fuel policies have helped to promote the use of ethanol as a viable alternative fuel. 

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