Fossil calorific value

On a uniform calorific value basis, coal constitutes 69% of the total estimated recoverable resources of fossil fuel in the United States. Petroleum and natural gas are about 7% and oil in oil shale, which is not as of this writing used as a fuel, is about 23%. The 1989 total recoverable reserves of coal are about 500 times the 1989 aimual production (2), whereas the reserves of oil and gas are smaller, the production and consumption rate of oil and gas in the United States is three times that of coal. 

The high hydrogen/carbon ratio of gas means that the quantity of water vapor in the products of combustion is greater than most other fossil fuels. The latent heat of this cannot be released in conventional appliances leading to a low net/gross ratio of calorific value of 90 per cent. (It is normal practice to quote gross CV in Europe net CV is often used. If net CV is quoted, efficiencies of over 190 per cent are possible.)... 

Ethylene and acetylene are diluted with natural gas in the gas injection equipment and fed to the boiler plant to utilize the energy they contain. The resins can also be used for energy production with the aid of suitable incineration plants. Thus, the high calorific values of these by-products and wastes can be used to produce energy in the form of steam and electricity, thereby avoiding the environmental pollution that would result from the burning of fossil fuels. 

Pressboards bind over 900 kg (C02-equiv.)/m (CO2 sink). On the basis of the calorific value, other fossil energy carriers with CO2 emissions of 700-800 kg can be saved per m of pressboard. 

In comparison to their fossil counterparts process chains based on renewable raw materials differ in many aspects. Operations for cultivation, harvesting, and provision of renewable raw materials take place in a natural environment. The raw materials accme spatially distributed on large areas. Amount and characteristics of the resources underlie seasonal variances and restrictions. As a rule, the abilities and capabUities for storage are hmited. Long-distance transports are disadvantageous because of comparable high water contents and low calorific values. 

This contradicts the aim to minimize the transport load of the renewable raw materials. An increasing demand for renewable raw materials, also induced to competing utilization pathways (see Section 4.4.3), will have price effects on the market. This is enforced as usually regional supply is intended Renewable raw materials have-in comparison to fossil raw materials such as coal and natural gas-a low specific calorific value with regard to their weight. 

Plastics have a higher calorific value than coal and superficially it would seem logical to use waste plastics instead of fossil fuels. However, in Europe (although not in Japan) public opinion is turning away from burning waste because of the perceived (although not necessarily real) dangers of toxic effluent. Incineration is not seen by the public to be a safe process and this conception may be difficult to reverse. 

The use of tire-derived fuel as a cofiring feedstock in power generation has many advantages. Hrst, because of the high calorific value of TDF, particularly the wire-free TDF, the cost of TDF in GJ (ot /10 Btu) is lower than that of any fossil fuel - with the possible exception of Powder River Basin coal delivered locally or to a mine-mouth plant - and is competitive with even the lowest cost biomass fuels. This, combined with the lower ash content of TDF (without steel) makes it a viable blending fuel. In addition, the sulfur content of TDF is less than most eastern bituminous coals and conq>arable to medium-sulfur coals throughout the world. 

The reason for this is that frequently all the fossil resources used during the manufacture of bioplastics are not taken into account, particularly when chemical modification of the biological raw material is involved during manufacture. Nor has the question of alternative use of agricultural land for polymer intermediates been accounted for when it competes with food production. The calorific value of hydrocarbon polymers when burned in an appropriate waste-to-energy incinerator is similar to the oil from which they were manufactured, whereas bio-based polymers are generally less useful as fuels. 

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