Separation, biomass benefits

Biomass resources will become more important in the future as alternative chemicals and fuel from fossil resources. Such alternatives can be carbon-neutral and renewable. Therefore, the use of biomass is of benefit for our global environments. The present study has clearly demonstrated a potential of woody biomass resources to be converted into useful chemicals in supercritical water. In addition, the products derived from cellulose and hemicelluloses were effectively separated from lignin-derived products. This raises the possibility of converting whole biomass substrates to alternative chemicals, and provides ample opportunities for human beings to produce useful biomass-based products as chemicals and bio-fuels W ithout using fossil resources... 

The biomass fractionation options and their economical benefits have been discussed by Blander and Hsu [57]. The objective of the fractionation is to separate different biomass components and subsequently convert the cellulose and the hemicellulose into products separately. To achieve this objective, mild treatment conditions, such as low temperature, low concentration of reagents (or easily recoverable reagents) and low pressures, are necessary. Under this biomass component fractionation scheme, cellulose sugar (glucose) and hemicellulose carbohydrates (mostly xylose) can be converted into products in different reactors to produce different products if so desired. 

A further investigation dealt with the importance of the complementary process. CE/Delft has compared the environmental effect nsing a separated plas-tic/paper fraction from household waste as fuel in a coal-tired power plant, co-tiring it with biomass, using it as fnel in a cement kiln, or incinerating it in a municipal waste incineration plant. The largest environmental benefit was obtained substituting coal in a power plant [14]. 

Alonso et have eliminated pre-treatment steps to fractionate biomass. They made use of certain composition in biomass to obtain fuels and chemicals, and the rest of fraction was separated. The work used gamma-valerolactone (GVL) as solvent, and the cellulosic fraction of lignocellulosic biomass can be converted into levulinic acid (LA), while at the same conditions the hemicellulose fraction can be converted into furfural. The furfural can be separated by distillation during the reaction or can be kept in the reactor and subsequently processed to produce furfutyl alcohol and LA. The lignin was solubilized in the GVL and separated. This process not only obtains the production of fuels and chemicals by utilization of hemicellulose and cellulose, but also it benefits from the elimination of pre-treatment and extraction/separation steps. 

The use of biomass, TDF, and other similar materials can have non-monetized benefits in terms of public image and public acceptance. Alternatively, local groups have vigorously opposed the use of some opportunity fuels. Opportunity fuels also can be opposed by fuel yard workers, if those workers feel that they are exposed to health issues. Manures, for example, have to be handled separately from coal. Economic considerations tend to be incredibly site-specific. Opportunity fuel availability and cost is subject to local conditions of supply and demand opportunity fuels frequently are bought and sold outside the normal conunercial channels of the energy market. Capital costs of... 

Successful implementation of an opportunity fuel prc ram must accomplish technical, environmental, an or economic in rovements. These can be increases in boiler capacity or efficiency, either through the use of a high calorific value fuel (petroleum coke, TDF) or by the design of the system used to introduce the fuel into the boiler (e.g., separate injection of biomass into a PC boiler can overcome pulverizer limitations on capacity). There can be reductions in emissions of SO2, NO CO and hydrocarbons, and mercury and other trace metals associated with the use of opportunity fuels. TDF fired with medium sulfur bituminous coal can have a significant benefit with respect to SO2 emissions. In roperly used, however, opportunity fuels can increase certain emissions including opacity. 

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