Carbon, energy content

The chemical characteristics of biomass vary over a broad range because of the many different types of species. Table 8 compares the typical analyses and energy contents of land- and water-based biomass, ie, wood, grass, kelp, and water hyacinth, and waste biomass, ie, manure, urban refuse, and primary sewage sludge, with those of cellulose, peat, and bituminous coal. Pure cellulose, a representative primary photosynthetic product, has a carbon content of... 

As for routes (2) and (3), the conclusion in this paper, as one can find back in many LCAs, is that the difference in environmental terms is not big. After all, both routes make use of the energy content (or carbon content) of the plastics, with a (close to) 100% efficiency. This is a striking point, since route (2) is labelled as incineration with energy recovery whereas route (3) is labelled as recovery , and hence in legal terms an option that scores... 

In cases where the aromatic C—C bonds were attacked and various water-soluble substances capable of extraction from oil were formed, a reduction in the total heating value of the fuel was consequently observed [137], Hence, such reaction was categorized as an industrially unacceptable reaction, since that pathway not only destroyed the carbon skeleton reducing the energy content of fuel but also converted DBT to 3-hydroxy-2-formylbenzothiophene without actually desulfurizing it to HBP. 

The conclusions of Hurt s study of year-by-year oxygen isotope ratios in 72 years of S. gigantea are thus supportive of the conclusions of the CIAP study [49] that solar variations influence the abundances of many kinds of chemical species in the stratosphere, and therefore influence the.amount of solar energy they absorb and re-radiate to earth, and therefore influence the surface temperature of the earth and especially the surface temperatures of the oceans. It is the surface temperature of the oceans which produces the phenomena we have discussed the isotope ratio variations in rain and hence in tree rings, the isotope ratio variations in the Greenland ice cap, in the organic carbon and uranium concentrations in sea cores, and furthermore variations of the sea surface temperature produces variations in the carbon-14 to carbon-12 ratio fractionation at the sea air interface and hence in the carbon-14 content of atmospheric carbon dioxide and hence in the carbon-14 content of tree rings. 

From the Fig. (10.13) it is seen that compounds with 8-11 carbon atoms have increased energy content. The reason for this is formation of intramolecular overcrowding of atoms and consequent production of strain due to non bonded atoms, also called Prelog strain. It increases the energy of the system. 

The replacement of timber products by nonrenewable materials is an unfortunate development, since it has been repeatedly shown that the use of timber does have associated environmental benefits compared with the use of nonrenewables (e.g. Marcea and Lau, 1992 Hillier and Murphy, 2000 Bowyer etal., 2003 Lippke etal., 2004). Timber has a lower embodied energy content (and hence a more favourable carbon emission profile) compared to most other building materials and can provide other benefits, such as improved thermal properties. It and the products made from it (in common with other renewable materials) can be used as a repository for atmospheric carbon dioxide. Wood is derived from a renewable resource, albeit potentially an exhaustible one unless it is managed correctly. Disposal of wood can be readily achieved with little environmental impact (subject to how the wood has been treated prior to disposal). 

Natural gas (NG) consists of 85-95% methane (CH ), which is the simplest hydrocarbon. NG is the cleanest burning alternative fuel. Exhaust emissions from NG vehicles are much lower than those from gasoline-powered vehicles. Combustion of NG reduces carbon dioxide content compared with diesel, but the lost efficiency when the Otto process is used means that carbon dioxide emissions increase. All in all combustion of NG in a gasoline engine gives rise to about as much carbon dioxide as the combustion of diesel in a diesel engine, measured in units of energy. 

In 1996, PNL estimated that a 100-ton-per-day facility using 0.06/kWh of electricity would cost approximately 125 per ton. Wastes with some energy content can be processed at much lower costs. For example, ash with high carbon content may cost less than 50 per ton to process. There is also the possibility that the waste form produced could be sold as construction materials or for some other application to offset processing costs (D126034). 

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