Appointment of gas-distributing stations (GDS)
The gas-distributing station (GDS), serves for pressure decline of gas to the level necessary under the terms of its safe consumption and provides also supply of gas of the caused quantity with a certain extent of cleaning and odorization.
On GDS the following main technological processes are carried out:
- purification of gas of solid and liquid impurity;
- pressure decrease (reduction);
- the accounting of quantity (expense) of gas before giving to his consumer.
To destination distinguish some GDS types:
- stations on branch of the main gas pipeline (on a final site of its branch to the settlement or an industrial facility) with the productivity from 5-10 to 300-500 thousand m3/hour;
- trade GRS for the gas preparation (removal of dust, moisture) extracted on trade and also for supply with gas of the settlement, adjacent to trade;
- the control and distributive points placed on branches from the main gas pipelines to industrial or agricultural facilities and also for food of ring system of gas pipelines round the city, with a productivity from 2-3 to 10-12 thousand m ³ / hour;
- automatic GRS for supply with gas of small settlements, state-farm and collective-farm settlements on branches from the main gas pipelines, with a productivity of 1-3 thousand m ³ / hour;
- gas control points (GRP), with a productivity from 1 to 30 thousand m ³ / hour, for pressure decrease of gas and its maintenance at the set level on city gas networks of high and average pressure;
- gas control installations for food of gas networks or entirely objects with a gas consumption to 1,5 thousand m ³ / hour.
The GDS main hubs and collecting condensate, heating, reduction, measurement, odorization, preparation of gas for own needs, preparation of the heat carrier, heating:
- switching knot;
- knot of purification of gas and collecting condensate;
- knot of prevention of hydrate formation;
- knot of preparation of gas for own needs;
- reduction knot;
- knot of preparation of the heat carrier;
- heating knot;
- gas metering station;
- gas odorization knot.
The knot of switching of GRS is intended for switching of a stream of gas of a high pressure from the automatic pressure on manual regulation on the bypass line, and also for prevention of increase of pressure in the line of supply of gas by means of safety fittings.
The knot of purification of GRS gas is intended for prevention of hit mechanical (firm and liquid) impurity in the processing and gas control equipment and control devices and automatic equipment.
The knot of prevention of hydrate formations is intended for prevention of frosting of fittings and formation of crystalline hydrates in pipeline communications and fittings.
The knot of reduction of gas is intended for decrease and automatic maintenance of the set pressure of the supplied gas.
The gas metering station is intended for the accounting of quantity of a consumption of gas by means of various flowmeters and counters.
The knot of odorization of gas is intended for addition in gas of substances with a pungent unpleasant smell (odorants). It allows to find in due time leak of gas on a smell without the special equipment.