Biomass aqueous-phase

The Dumesic group at the University of Wisconsin has developed a method to upgrade the aqueous-phase sugars and alcohols derived from biomass into either H or alkanes [7, 55-61]. For the production of H from biomass, aqueous-phase reforming of the sugar solution over many different catalysts has been studied [56]. Silica-supported Ni (19.1 wt %), Pt (5.85 wt %), Pd (4.78 wt %), Rh (9.37 wt %), Ru... 

In addition to these relatively simple liquid phase aqueous systems, it is necessary to identify situations in which any of these aqueous phase reservoirs come into physical and chemical contact with solid surfaces (e.g., rocks, biomass, sediments, soils, magma etc.). In general, the presence of two or more phases (liquid plus one or more solid phase) provides important constraints on the chemical reactions that may occur within the system as a whole. 

The typical bioreactor is a two-phase stirred tank. It is a three-phase stirred tank if the cells are counted as a separate phase, but they are usually lumped with the aqueous phase that contains the microbes, dissolved nutrients, and soluble products. The gas phase supplies oxygen and removes by-product CO2. The most common operating mode is batch with respect to biomass, batch or fed-batch with respect to nutrients, and fed-batch with respect to oxygen. Reactor aeration is discussed in Chapter 11. This present section concentrates on reaction models for the liquid phase. 

Comparing the adsorption results obtained from octa-BDE mixture components with deca-BDE results (Fig. 8), it is obtained a higher adsorption for the less brominated compounds. This is due to its greater solubility in aqueous phase, and hence it has higher bioavailability to interact with biomass. 

Separation of the aqueous, oil, and biocatalyst (solid/biomass paste) phases ... 

Huber, G. W. Chheda, J. N. Barrett, C. J. Dumesic, J. A., Production of liquid alkanes by aqueous-phase processing of biomass-derived carbohydrates. Science 2005, 308(5727), 1446-1450. 

The organic phase was separated from the aqueous phase containing biomass by centrifugation. Epoxide products were recovered from the organic phase by vacuum distillation. 

The catalytic aqueous phase reforming might prove useful for the generation of hydrogen-rich gas from carbohydrates extracted from renewable biomass and biomass waste streams. The biomass-derived hydrocarbons are suitable to hydrogen generation from biomass, as well as for the reforming. 

An alternative approach for the utilization of biomass resources for energy applications is the production of dean-buming liquid fuels. In this respect, current technologies to produce liquid fuels from biomass are typically multi-step and energy-intensive processes. Aqueous phase reforming of sorbitol can be tailored to produce selectively a clean stream of heavier alkanes consisting primarily of butane, pentane and hexane. The conversion of sorbitol to alkanes plus CO2 and water is an exothermic process that retains approximately 95% of the heating value and only 30% of the mass of the biomass-derived reactant [278]. 

Catalytic dihydrogen production form biomass is known as aqueous phase reforming (APR) [38]. It is interesting to note the absence of CO in the dihydrogen produced by the biosystem, which makes it immediately suitable for use in fuel-cells... 

A possibly more sophisticated method for utilizing biomass to produce synthesis gas is by aqueous phase reforming (APR), a processing method that was developed for carbohydrates and other more readily accessible biomass oxygenates by Dumesic et Valenzuela et al. however,... 

The crude paclitaxel is recovered from the rich aqueous fermentation broth by liquid/liquid extraction with a mixture of isobutyl acetate (IBA) and isopropanol (IPA), both class 3 solvents. The waste aqueous phase is stripped to remove residual organic solvents (IBA/IPA), treated with sodium hydroxide to deactivate any paclitaxel residues, and processed through a standard wastewater treatment facility. The amount of solid waste biomass generated in the process is negligible. 

HTC, as compared to all other current techniques of biomass/energy conversion, is not only rather simple and fast (down to 90 minutes) but also converts practically all the carbon atoms of biomass into the final coal powder (i.e. CE is close to 1). At the same time, relevant salts (e.g. K+) stay in the aqueous phase and can be back-donated to the ecosystem. 

APR [Aqueous-Phase Reforming] A process for making hydrogen or lower alkanes from carbohydrates, biomass, or glycerol from biodiesel production. The catalyzed process operates at a relatively low temperature (180 to 260°C). Developed from 2001 at the University of Wisconsin and later by Virent Energy Systems, which operated a demonstration plant from 2006. 

Recently, extensive efforts have been made to synthesize liquid hydrocarbons from biomass feedstocks. In 2004, Dumesic and co-workers reported that a clean stream of alkanes could be produced by aqueous phase reforming of sorbitol over a bifunctional catalyst. The sugar is repeatedly dehydrated using a solid acid catalyst and then hydrogenated using a precious metal catalyst such... 

Processes for depolymerization of the biopotymer, sqiaration of the various chemical types, and aqueous phase processing all must be established for biomass conversion to chemical products to become widespread. 

Poisoning of catalysts.in aqueous phase processing of biomass-derivedfeedstocks... 

Properties of Bio-Oil and its Blends with Methanol and a Pyrolytic Aqueous Phase. Biomass Bioenergy, In press. 

Boucher M.E., Chaala A., Pakdel H. and Roy C. (2000), Bio-Oils Obtained by Vacuum Pyrolysis of Softwood Bark as a Liquid Fuel for Gas Turbines. Part II Stability and Ageing of Bio-Oil and its Blends with Methanol and a Pyrolytic Aqueous Phase Biomass Bioenergy, In press. 

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