gas industry, occupational health

From Big Medical Encyclopedia

GAS INDUSTRY, occupational health — the industry of the heavy industry covering all types of production natural and productions of an artificial gas, storage, transfer for its use as an energy source and chemical raw materials.

Gas in a subsoil of the earth accumulates in tanks (layers) consisting of the porous rocks surrounded from all directions with the dense low-permeable breeds tires squeezing layer together with the gas which is in it.

Gas comes to an initial stage of operation of the field from a subsoil under big (to 100 atm and more) reservoir pressure. In process of depletion of deposits the reservoir pressure falls, and methods of active influence can be applied to its maintenance (underground explosion, pumping water in layer, etc.). Working conditions of the personnel servicing trade in many respects depend on chemical composition of the extracted gas. The less impurity contain gas, the technology of production is simpler and it is safer than a working condition.

Gas of natural fields for 94 — 98% consists from methane (see), in nek-ry cases there is an impurity hydrogen sulfide (see), condensate (the fraction of hydrocarbons consisting of vapors of gasoline, kerosene, ligroin, solar oil), moisture and sand. Impurity reduce caloric power of gas, worsen external environment of gas pipelines.

For gas sweetening from impurity complex gas processing units are equipped. Production factors, adverse for health of workers, on such installations: intensive (120 — 125 dB) high-frequency (6300 — 8000 Hz) the noise created by gas flows, circulating in intra shop pipelines, air pollution of a working zone hydrocarbons (see), hydrogen sulfide (in the presence of it in gas), vapors of absorbents — the substances which are applied to gas dewatering. On domestic installations in quality of absorbent diethylene glycol is most often applied. For the prevention of intake of vapors of absorbent in air of workrooms reliable tightness of devices and communications shall be provided.

Gas sweetening from condensate and hydrogen sulfide is made on natural-gasoline plants, products to-rykh, except purified gas, gasoline and sulfur are. Aqueous solution of monoethanol amine is applied to extraction of hydrogen sulfide from gas. At disturbance of sealing of the equipment the atmosphere of the platform of these plants and air of work rooms can become soiled hydrogen sulfide, hydrocarbons, sulphurous anhydride, vapors of monoethanol amine. Safety of works at repair of the equipment and accident elimination is reached by use of the individual protective agents (isolating and the filtering gas masks) and overalls.

The specific and finally not solved problem G. of the item is fight against hydrates — the solid matters which are formed at interaction of hydrocarbons of gas with the water molecules and outward reminding snow or ice. Low bedded temperatures of northern fields and severe climatic conditions of these areas create danger of formation of natural gas hydrates in wells, in trade gas-collecting networks and in the main gas pipelines.

For the prevention of formation of hydrates in wells under pressure various inhibitors of hydrate formation — solution of calcium chloride, methanol, diethylene glycol are entered. Control and process control are automated.

The purified and drained gas from installations of complex preparation or from natural-gasoline plants comes to the main gas pipelines for delivery to consumers and can move under the natural (bedded) or artificial pressure created by compressors (head and intermediate compressor stations). At gas engine compressor stations along with intensive noise unfavorable microclimatic conditions due to excess formation of heat are created. A radical measure of improvement of working conditions at gas-compressor stations is full automation of management of them. Workers shall be provided with individual protection equipment from noise (see. Protivoshuma ).

Service of a linear part of the main gas pipeline is carried out by linemen, to-rye for change do big transitions, carry out a number of heavy manual works. A perspective measure for improvement of work on these sites G. of the item — creation of the special repair and recovery crews equipped with modern automobiles, communication and mechanization of works.

A labor-consuming type of works is elimination of the hydrated traffic jams which are formed in a linear part of the main gas pipelines. Less labor-consuming and more hygienic also tracer techniques of detection of hydrated traffic jams are the most progressive radar. At a tracer technique of definition of hydrated traffic jams strict observance of the measures of protection working from ionizing radiation is necessary. For elimination of hydrated traffic jams, length to-rykh can reach several hundred meters, enter methanol into the pipeline, reduce in it pressure, blowing and producing the gas concluded in the emergency site in the atmosphere or warming up the corked sections of the pipeline naked flame, hot water or steam.

Works on elimination of full or partial obstruction of the main gas pipelines are followed by the operations demanding big physical tension. In the conditions of Far North special measures for prevention of overcoolings and frostbites are necessary (see. Acclimatization , Freezing injury , Overcooling of an organism ).

For workers of the complex gas processing units and natural-gasoline plants which are directly occupied with gas sweetening from hydrogen sulfide are obligatory preliminary (at revenues to work) and periodic (once in 12 months) medical examinations (see. Medical examination ).

Bibliography: N. M. bikes, etc. Glycols and experience of their use in the oil and gas industry of M., 19 70, bibliogr.; And m and d e e in M. M. and Obukhov V. M. Occupational health and industrial hygiene in oil industry of Bashkiria, Ufa, 1971, bibliogr.; To about r about-tayev Yu. P., Kuliyev A. M. and Musayev R. M. Fight against hydrates at transport of natural gases, M., 1973, bibliogr.; Standards of radiation safety (NRB-69), M., 1972; Sidorenko M. V. Increase in reliability of gas supply, M., 1968, bibliogr.

A. K. Monkevich.