Hydrocarbons gaseous paraffin

A gaseous paraffinic hydrocarbon, CHj.CHj that is colorless and odorless and normally found in natural gas, usually in small proportions. It is slightly heavier than air and practically insoluble in water. When ignited in atmospheric burning it produces a pale faintly luminous flame with little or no smoke production. With excess air during combustion it produces carbon dioxide and water, with limited air supplies the combustion process will produce carbon monoxide and water. It forms an explosive mixture with air over a moderate range. 

There is abundant field evidence for the existence of SP cells over petroleum reservoirs. Indeed this evidence itself was used to find petroleum reservoirs for almost 100 years before the cells were recognised. It includes gaseous and liquid hydrocarbon seeps, paraffin deposits, halo-type metal anomalies, iron and manganese deposition, carbonate cementation, hard-drilling areas, magnetic anomalies (associated with magnetite mineralisation) and elevated uranium concentrations (Tomkins, 1990). Chapters 5-7 of this volume and references provided therein document many of these features. 

Thus, by the occurrence of many variations of processes, such as these, thermal cracking produces a mixture of gaseous and liquid hydrocarbons of paraffinic (saturated) and olefinic (unsaturated) types, plus coke (Eq. 18.16). 

Utilization of the enormous quantities of gaseous paraffin hydrocarbons by means of oxidation has been the object of much research. These hydrocarbons are available in tremendous quantities in natural gas, in the products from the cracking of petroleum, in coke oven gas, and in car-buretted water-gas. The volume of methane, ethane, propane and butane available in the United States alone during the year 1927 has been estimated to have been over 2,472,000,000,000 cubic feet.1 Table VII shows in... 

Numerous materials have been reported and patented as catalysts for the oxidation of the gaseous paraffin hydrocarbons. The majority of these, consisting mainly of metals or metal oxides, are far too active and too nonspecific in action to permit the recovery of more than small amounts of intermediate oxidation product. With such relatively mild catalysts as copper oxide and glass surfaces, some high yields of formaldehyde have been obtained from methane and ethane under experimental conditions. Under conditions where less than 10 per cent of the entering hydrocarbon is oxidized, conversions of over 50 per cent of reacting hydrocarbon to formaldehyde have been reported. The use of elevated pressures, as shown in Fig. 9-6, for the oxidation of methane and ethane has been found to enhance yields of useful products. 

Gaseous paraffinic hydrocarbon (C4H10) is usually a mixture of iso- and normal butane, also called, along with propane, liquefied petroleum gas (LPG). 

Direct catalytic oxidation of hydrogen sulfide to elemental sulfur in the presence of gaseous paraffinic hydrocarbons or other gases has been reported by Grekel (1959). Although pilot-plant work indicated good conversions and no effect on the hydrocarbons, the process has so far not been successfully commercialized. 

Pressure Pyrolysis of Gaseous Paraffin Hydrocarbons, Ind. Eng. Chem., 28, 324 (1936). 

The reaction produces a mixture of gaseous, liquid and solid paraffinic hydrocarbons. 

Liquefied Petroleum Gas The term liquefied petroleum gas (LPG) is applied to certain specific hydrocarbons which can be liquefied under moderate pressure at normal temperatures but are gaseous under normal atmospheric conditions. The chief constituents of LPG are propane, propylene, butane, butylene, and isobutane. LPG produced in the separation of heavier hydrocarbons from natural gas is mainly of the paraffinic (saturated) series. LPG derived from oil-refinery gas may contain varying low amounts of olefinic (unsaturated) hydrocamons. 

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