During anaerobic (methane or oxygen-free) fermentation takes place in the bowels of the earth biodegradation of organic matter with the release of methane (CH4 - the simplest hydrocarbon paraffin).This phenomenon can be described by the equation of the reaction: organic material + H2O → CH4 + C5H7NO2 + CO2 + NH4 + H2CO3.The result is a useful natural resources.It lies under layers of earth and is in gaseous or crystalline (in the form of gas hydrates - methane compound with water, stable at high pressures and low temperatures, are in permafrost) state.Furthermore, it may be dissolved in water or in oil.The composition of natural gas is not constant and varies from field to field.
main component of this fossil is methane, its content is in the range from 91 to 98%.Also contains a heavy paraffinic hydrocarbons: butane (C4H10), propane (C3H8), ethane (C2H6).The presence of inorganic substances which are: hydrogen (H2), nitrogen (N2), carbon dioxide (CO2), hydrogen sulfide (H2S), helium (He), water vapor (H2O).The properties and composition of natural gas, as well as test methods are regulated by GOST 5542-87.This interstate standard developed and introduced in the Soviet Union, and now operates in several CIS countries.It applies to natural gas fuel that is used as fuel and raw materials in industry, as well as fuel in the domestic economy.
Himalayan it at a depth of one to several kilometers (lower than the oil), as it is formed at a higher pressure and higher temperatures.Its depth depends on the field, for example, near Novy Urengoy it is mined at a depth of 6 km.Produced by wells from underground gas enters the collection system, and then it is prepared and transported to the consumer.To prepare mounted near the mine and allowed ad hoc installation, which is designed to remove water (prevents transportation) and sulfur compounds (active substances are corrosion that reduce equipment lifetime and can result in emergency situations).The composition of natural gas is analyzed before and after drying it in an absorption column and the purified hydrogen sulfide.
In plants also produce helium.In this case, two problems are solved.The first - an inert helium (He) reduces the quality characteristics provided by GOST 5542-87, for example, heat of combustion.The second - dedicated to the installation of low-temperature helium separation is necessary in many sectors of the economy valuable product, it is produced at the fields with more than 0.1%.Produced under high pressure helium is transported to consumers in steel cylinders.The qualitative composition of helium as the gas composition was analyzed for impurities in special chemical laboratories.
Content hydrocarbon components are analyzed in accordance with GOST 23781-87.According to the normative document determining the chemical composition of natural gas chromatographic methods.Helium, hydrogen, nitrogen, oxygen and methane - chromatograph with thermal conductivity detector, wherein the chromatographic column is set to the molecular sieve.Hydrocarbons and carbon dioxide - chromatograph with a thermal conductivity detector and column filled with sferohromom treated with ether TEGM.The content of components C4-C8 - chromatograph with a flame ionization detector and a chromatographic column packed with inert solid support (Chromaton) treated with dimethylsilicone or squalane.Calculate the gas composition in percent by volume.
Explore also other characteristics that determine the quality of the product at various stages of production: from the moment of production to delivery to the consumer.For example, the water content is set by the dew point, GOST 20060-83.The relative density, higher and lower calorific value calculated in accordance with GOST 22667-82 and on the basis of component composition obtained by the chromatographic methods of analysis GOST 23781-87.To determine hydrogen sulfide (H2S), sulfur and mercaptan (RSH) using one of three methods (fotokalorimetrichesky, potentiometric or iodometric) which describes GOST 22387.2-97 and selected depending on the content of the analytes.All the studies on which it becomes known composition of natural gas is carried out in chemical laboratories, which must meet the requirements of GOST R ISO / IEC 17025-2009.