FUELS 1. Gaseous Fuels Gaseous fuels of value in commerce include natural hydrocarbon gases, gases manufactured solely for use as fuels. And gases obtained as by-products of some industries. The following classification of gaseous fuels includes all types of commercial importance. a. Natural Gas- associated with petroleum oil deposits, with coal seams or decay of organic matter. b. Manufacture Gases b.1 From Wood- By distillation or carbonization (Wood Gas) b.. From Peat- By distillation or carbonization (Peat Gas) b.3 From Coal- By carbonization (Coal Gas) • • By gasification (i) Producer Gas (in air) (ii) Water Gas (in air and steam) (iii) Lurgi Gas (in O2 and steam) By hydrogenation Blast Furnace Gas (as a by-product of the reduction of ores) b.4 From Petroleum and oil shale • • Refinery Gas (by cracking) Oil Gas (by hydrogenation, by water gas reaction, by partial oxidation) 2. Liquid Fuels Liquid fuels may be divided into two main classes, based on how they will be used. a. Light Oils or spirits- suitable for use with internal combustion engines and jet engines. It includes: a.1 The lighter, more volatile fractions obtained by distilling or cracking natural petroleum oils and related natural deposits, a.2 The light fractions obtained by the hydrogenation of coal, coal tar or heavy oil residues. a.3 The light fractions obtained by the synthesis of hydrocarbons by the Fischer-Tropsch Process a.4 Alcohols, particularly methyl and ethyl alcohol, obtained by synthesis or fermentation process. a.5 Benzole, obtained by the distillation of coal tar or by extraction from coal gas. a.6 Alcogas or Gasohol- mixtures of methyl or ethyl alcohol and gasoline. Of these, only the most volatile and cleanest products, gasoline or petrol (natural or synthetic), benzole and alcohol are suitable for the spark ignition engine. The next higher fraction of petroleum oil, shale oil and synthetic oil, generally included in the class of oils known as paraffin, kerosene or naphtha are suitable for jet engines. b. Furnace Oils- include the heaviest grades of natural petroleum oils and lubricating oils from which the more valuable lubricating oil and fractions have been removed by distillation. 3. Solid Fuels Solid organic fuels are classified into natural and artificial fuels a. Natural Solid Fuels a.1 Wood- may be burned directly as a fuel or maybe converted into charcoal or producer gas. Sawdust is sometimes burnt at sawmills supplemental with oils to reduce fuel cost. a.2 Peat- brown fibrous mass of partially decayed plant material that has accumulated under water logged conditions. a.3 Lignites- immature coals that are intermediate in composition between peat and bituminous coals and about 1 to 100 M years old. a.4 Coals-compact stratified mass of mummified plant debris that has accumulated during past geological ages about (100-300 M years old) and has been altered by processes involving biochemical action, submersion in water and action of heat and pressure. b. Artificial Solid Fuels b.1 Wood Charcoal- solid residue from the carbonization of wood which involves heating wood strongly in the absence of oxygen. b.2 Peat Charcoal- made by carbonizing peat at low temperature b.3 Lignite Briquettes- air dried lignites b.4 Lignite Coke- air dried and carbonized lignite b.5 Coke- Carbonized coal
