Solids, fuel

Fuels are conveniently classified as solids, liquids, and gaseous fuels. Solid fuels include peat, wood, and coal and can encompass solid rocket fuels as well as metals. The earliest fuels used by man were nonfossil fuels of wood and oil from plants and fats from animals. The windmill and water wheels were other sources of energy. 

Sources of power have changed with the years and will continue to change as shown in Fig. 1.2. In 1992, approximately 7% of the world s power was supplied by hydroelectric plants and the remaining 92.5% from fuels. Natural gas provides 22% of the total power petroleum, 40% coal, 25% (of which 7% is derived from hard coal and 18% from the soft coals) and nuclear fuels provide about 7%. But in 2005, approximately 16.6% of the world s power was supplied by hydroelectric plants 65.9% by thermal power plants 15.2% by nuclear power plants and 2.1% by geothermal, solar, and wind power plants. Oil, which has displaced coal as the major fuel, will soon be replaced by natural gas which in turn will be eventually replaced by nuclear energy and environmentally friendly geothermal, solar, and wind power energy. 

Roussak and H.D. Gesser, Applied Chemistry A Textbook for Engineers and Technologists, DOI 10.1007/978-l-4614-4262-2 2, Springer Science+Business Media New York 2013 

VEGETABLE MATTER WOOD Fermentation + Heat CH4 + COj + HjO evolved 

Wood was obviously man s first fuel, followed by animal fats and vegetable oil. There is evidence that candles were used during the first Minoan civilization about 3000 B.C. Coal was used by the Chinese about 100 B.C. and the black stone was reported to be used by Greek smiths about 250 b.c. The Romans in Great Britain also used coal. Marco Polo describes the mining of black stone in his travels 1271-1298 a.d. 

The most widely used form of the carbonaceous fuels is perhaps the solid fuel, coal. Though occurring basically in the solid form, coal can be converted to both liquid and gaseous forms. In the solid form, coal is basically of two types charcoal (prepared by carbonization of wood) and mineral coal (obtained from coal mines). Coal is found on every continent, 

The formation of mineral coal is not an instantaneous process, but is an extremely lengthy one, spread over an extended period. Millions of years ago, when the temperature was moderate and rainfall was heavy, vegetation was quite thick, especially in the low-lying areas of the Earth. Coal-forming plants probably grew in swamps, and as the plants died, their debris gradually formed a thick layer of matter on the swamp floor. Over a prolonged period, this matter hardened into a substance called peat. The peat deposits became buried under sand or other mineral matter. As the mineral matter accumulated, some of it turned 

The composition of coal is conveyed by representing its proximate and ultimate analysis. The former implies determination of contents of moisture, volatile matter, fixed carbon, and ash, while the latter implies total carbon, hydrogen, oxygen, nitrogen, sulfur and ash. Here, an account will be provided of the constituents of coal, moisture, volatile matter, ash, fixed carbon, and some miscellaneous components. 

Calorific value This should be high so that a high heat is obtained from a small quality of coal. This results in reduction of the cost of storage and also handling. 

Moisture content This should be low. It reduces the heating value. In monetary terms moisture is incurring a loss, since it is paid for at the same rate (by weight) as the coal itself. 

Mineral matter derived from ash constituents of liquid and solid fuels can vaporize and condense as sub-micron-size aerosols. Larger mineral matter fragments are formed from mineral inclusions which melt and resolidify downstream. 

Sulfate particles formed in the gas phase can condense. In addition, sulfate can become bound to metals and can be adsorbed on unburned carbon particles. 

Unhumed carbon includes unburned char, coke, cenospheres, and soot. 

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Desulfurize the fuel. Most types of fuel can be desulfurized. However, as we go from gaseous to liquid to solid fuels, the desulfurization process becomes increasingly difficult. 

Bi-Gas process A high-pressure operation for the conversion of solid fuel into substitute natural gas (SNG) using two stages of gasification. 

Carbon monoxide and excess steam are normally passed over a cobalt catalyst at about 250-300 C resulting in greater than 99% conversion of CO to COj. This conversion reaction is widely used in oil or solid fuel gasification processes for the production of town gas or substitute natural gas. ... 

R. L. Mednick, Proceedings of the Eleventh Annual EPRJ Contractors Conference on Clean Eiquid and Solid Fuels, EPRIAP-5043-SR, Electric Power Research Institute, Palo Alto, Calif., 1987. 

Various processes can be used to produce energy or gaseous, liquid, and solid fuels from biomass and wastes. In addition, chemicals can be produced by a wide range of processing techniques. The following Hst summarizes the principal feed, process, and product variables considered in developing a synfuel-from-biomass process. 

Fig. 2. Overall schematic of solid fuel combustion (1). Reaction sequence is A, heating and drying B, solid particle pyrolysis C, oxidation and D, post-combustion. In the oxidation sequence, left and center comprise the gas-phase region, tight is the gas—solids region. Noncondensible volatiles include CO, CO2, CH4, NH, H2O condensible volatiles are C-6—C-20 compounds oxidation products are CO2, H2O, O2, N2, NO, gaseous organic compounds are CO, hydrocarbons, and polyaromatic hydrocarbons (PAHs) and particulates are inerts, condensation products, and solid carbon products.

M. A. DeLuchi, E. D. Laison, and R. H. WiUiams, Hjdrogen andMethanol Production and Use in Fuel Cell andintemal Combustion Engine Vehicles—-A preliminary Assessment, Vol. 12, Solid Fuel Conversion for the Transportation Sector, ASME, Fuels and Combustion Technologies Division, New York, 1991, pp. 55-70. 

J. R. Dietrich and W. H. Zion, Solid Fuel Reactors, Addison-Wesley Publishing Co., Inc., Reading, Mass., 1958. 

When used for ceramic heating, furnaces are called Idlus. Operations include drying, oxidation, c cination, and vitrification. These Idlus employ horizontal space burners with gaseous, hquid, or solid fuels. If product quahty is not injured, ceramic ware may be exposed to flame and combustion gases otherwise, muffle Idlus are employed. Dutch ovens are used frequently for heat generation. 

Anthony G. Fonseca, Ph.D., Director, Coal Utilization, CONSOL, Inc. Member, American Chemical Society, Society for Mining, Metallurgy, and Extraction. (Solid Fuels)... 

Solvent-Refined Coal (SRC) This processing concept was initiated by the Pittsburgh Midway Coal Mining Co. in the early 1960s. The SRC-I process operating mode is designed to produce a solid fuel for utility applications. Typical operating conditions and product yields for SRC-I are shown in Table 27-14. 

There are three basic modes of burning solid fuels, each identified with a furnace design specific for that mode in suspension, in a bed at rest on a grate (fuel-bed firing), or in a fluidized bed. Although many variations of these generic modes and furnace designs have been devised, the fundamental characteristics of equipment and procedure remain intact. They will be described briefly. 

Pul verizers The pulverizer is the heart of any solid-fuel suspen-... 

An advantage of a stoker-fired furnace is its easy adaptability to firing almost any unsized solid fuels. Bark, bagasse, or refuse can normally be fired on a stoker to supplement the coal with a minimum amount of additional equipment. Thus, such supplementaiy waste fuels may be able to contribute a higher percentage of the total heat input in a stoker-fired furnace than in a PC furnace without expensive equipment modifications. 

With a solid fuel, such as coal or wood, a series of steps are involved in combustion. These steps occur in a definite order, and the combustion device must be designed with these steps in mind. Figure 6-6 shows what happens to a typical solid fuel during the combustion process. 

Cooper, J. A. (ed.), "Residential Solid Fuels Environmental Impacts and Solutions," Oregon Graduate Center, Beaverton, OR, 1981. 

The code provides for the testing of gas turbines supplied with gaseous or liquid fuels (or solid fuels converted to liquid or gas prior to entrance to the gas turbine). Test of gas turbines with water or steam injection for emission control and/or power augmentation are included. The tests can be applied to gas turbines in combined-cycle power plants or with other heat recovery systems. 

Colbalt Hydrogenations of solid fuels and fuel oils Manufacture of terephthalic acid High pressure production of aldehydes Lung irritation (hard metal disease) respiratory sensitization... 

Determination of smoke emission from manufactured solid fuels for domestic use. Part 1 General method for determination of smoke emission rate. Superseded BS 3841 1972 Determination of smoke emission from manufactured solid fuels for domestic use. Part 2 Methods for measunng the smoke emission rate. Superseded BS 3841 1972... 

In combustion processes tests, it has been noticed that Pd-catalyzed SnO, sensors follow the variations in the concentration of CO in the combustion gases, even in the case of solid fuels. 

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