Design of gas supply systems

Boiler house internal gas supply

4.1 Gas Supply Diagram

Boiler house is supplied with gas from external medium-pressure gas pipeline. The gas supply diagram of the boiler house is shown in the drawings. The elements of the boiler house gas pipelines diagram are:

- general disconnecting device at gas pipeline inlet to boiler room

-thermo shut-off valve

-gas control unit

- gas flow measurement unit

- disconnectors on the branches of gas pipelines to the units

-fuel gas pipelines

-safety gas pipelines

The gas pipeline is introduced into the boiler house through the wall of the structure in the case, which is a section of pipe of larger diameter than the gas pipeline. The space between the case and the gas pipeline is sealed with a ground linen strand, and bitumen is poured from the ends. The case is designed to protect the gas pipeline from damage in case of minor deformations of the wall.

The disconnecting device at the inlet is designed to disconnect the boiler room in case of repair or accident, as well as when it is stopped for a long time.

The gas pipelines in the boiler room are open and attached to the walls (columns) using special metal brackets (supports) or suspensions with clamps. Connection of gas pipelines is made on welding. Split connections are provided in places of installation of shutoff valves, gas devices, pressure regulator and other devices.

Gas pipelines of the boiler house are provided with blowdown pipelines from the most remote sections of the gas pipeline, as well as from branches to each boiler. Purge gas pipelines ensure removal of air and gas-air mixture from gas pipelines before boiler start-up, and also displace gas with air during repair or long-term shutdown of the boiler house. The blowdown gas pipelines are provided with a disconnecting device, as well as a nozzle for gas sampling.

Purge gas pipelines are brought from buildings to a height of not less than 1 m above the roof cornice, at a place where safe conditions for gas dispersion are provided. A protective umbrella is mounted at its end to prevent atmospheric precipitation from entering the blowing gas pipeline.

Diameters of gas pipelines are determined by means of hydraulic calculation.

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