Conversion of Biomass to

Chaudret and coworkers reported the synthesis of the first / -H2 complex of a Group 5 metal [148]. The reaction of Cp2 Ta(H)(CO) (Cp = C5H5 or CsH/Bu) reacts with HBF4 at -78°C to yield the corresponding / -H2 complex. 

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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. 

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. 

Cellulase is a collection of enzymes that together can hydrolyze cellulose to glucose, a key step in the low-cost conversion of biomass to ethanol. Such a process would be useful for three reasons. First, in large scale it could contribute to the substitution of the renewable fuel ethanol for petroleum-based gasoline. Second, it is known that the addition of 5% ethanol to... 

Approximately 89 million metric t of organic chemicals and lubricants, the majority of which are fossil based, are produced annually in the United States. The development of new industrial bioproducts, for production in standalone facilities or biorefineries, has the potential to reduce our dependence on imported oil and improve energy security. Advances in biotechnology are enabling the optimization of feedstock composition and agronomic characteristics and the development of new and improved fermentation organisms for conversion of biomass to new end products or intermediates. This article reviews recent biotechnology efforts to develop new industrial bioproducts and improve renewable feedstocks and key market opportunities. 

Gallezot P (2011) Conversion of biomass to selected chemical products. Chem Soc Rev. doi 101039/cl0103 lcsl 15147a... 

Crocker M, editor. Thermochemical conversion of biomass to liquid fuels and chemicals. Cambridge, UK Royal Society of Chemistry 2010. 

Neathery JK. Chp 4 Biomass Gasification in Thermochemical Conversion of Biomass to Liquid Fuels and Chemicals (ed. Crocker, M.). Cambridge,UK RSC Publishing 2010, p. 73-4. 

Ohgren et al., 2006). Recent work suggests that L. brevis and L. buchneri simultaneously consume C5 and C6 sugars (Kim et al., 2007 Liu et al., 2008), a factor that facilitates complete consumption of all lignocellulosic-derived sugars without catabolite repression. As a result, these strains are desirable hosts for additional manipulations toward efficient conversion of biomass to fuels and chemicals. 

Fig. 33.3. General schematic of a process for thermochemical conversion of biomass to fuels, heat, and power. ASU = Air Separation Unit, HRSG = Heat Recovery Steam Generator.

This approach to the preliminary assessment of the potential of biomass energy presumes that suitable conversion processes are available for conversion of biomass to SNG. Other processes could be used to manufacture other synfuels such as synthesis gas, alcohols, esters, and hydrocarbons. The direct route, alluded to in Fig. 2.1 as natural production of hydrocarbons, can possibly bypass the harvesting-conversion routes. As already mentioned, some biomass species produce hydrocarbons as metabolic products. Natural rubber, glycerides, and terpenes from selected biomass species, for example, as well as other reduced compounds could be extracted and refined to yield conventional or substitute fossil fuels. 

Knowledge of the effects of various independent parameters such as biomass feedstock type and composition, reaction temperature and pressure, residence time, and catalysts on reaction rates, product selectivities, and product yields has led to development of advanced biomass pyrolysis processes. The accumulation of considerable experimental data on these parameters has resulted in advanced pyrolysis methods for the direct thermal conversion of biomass to liquid fuels and various chemicals in higher yields than those obtained by the traditional long-residence-time pyrolysis methods. Thermal conversion processes have also been developed for producing high yields of charcoals from biomass. 

It appears that further research on HI chemistry could lead to processes for direct conversion of biomass to hydrocarbons without the economic penalty associated with operation at high pressure and temperature. The key to the value of such developments resides in the ability to recycle HI. Note that loss of only a small amount of the HI reacted can make the process quite uneconomical, so if it is developed to the point of commercial use, iodine recoveries would have to be substantially improved. 

The other prerequisite is the fact that society not only expects competitive, but clean systems and products as well. One has to look at the whole chain of production and conversion of biomass to get a clear picture of the environmental consequences. For the feeding material there is a strong preference for woody or grassy materials [7]. The emission of the power plant has to be low and the strict Dutch rules for waste incineration installations are taken as a point of departure [5]. The whole-integrated system has the further advantage that it produces renewable products for which there is a market today electricity, heat, and FT-liquids. Furthermore, the liquid fuels form an attractive energy carrier and storage medium. 

Agblevor, F.A., B. Rejai, D. Wang, A. Wiselogel, and H.L.Chum (1992) Thermochemical Conversion of Biomass to Fuels and Chemicals, the Effect of Storage Conditions on Pyrolysis Products, Proceedings Alternative Energy-Liquid Fuels from Renewable Resources, Dec. 13-15, 1992, Nashville, TN. 

Water used in this supercritical state behaves very differently from water under normal pressure and temperare." In such a supercritical state, the water can be expected to act as an acid or base, but by returning the system to ordinary conditions before pyrolysis occurs, glucose and its derivatives could be obtained in water from cellulose. Therefore, supercritical water treatment can be superior to enzymatic saccharification or oidinaiy acid hydrolysis mentioned above, for the chemical conversion of biomass to useful chemicals. 

Two major types of gasifiers for solid fossil fuels are available commercially at the present time. The cocurrent or downdraft versions are used in small internal combustion engine applications for sawmills, remote communities, and to satisfy power needs for developing nations. A more recent advance is the fluidized-bed gasifier, which is appropriate for larger-scale conversion of biomass to producer gas or other products. 

Note Cellulase derived from the thermophilic soil fungus Thielatia terrestris functions at a much higher temperature than other types and is thus much more effective in decomposing cellulose. This indicates its possible use in conversion of biomass to energy. Commercial development of this product is expected. 

Thermochemical Conversion of Biomass to Fuels and Feedstocks An Overview of R D Activities Funded by the Department of Energy... 

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