Anti-freezing system and method for zero-power operation air cooling island of low-pressure cylinder of direct air cooling unit

Abstract

The invention provides an anti-freezing system and method for a zero-power operation air cooling island of a low-pressure cylinder direct of an air cooling unit. The system comprises a steam turbine,an exhaust device and an air cooling island which are connected sequentially, one branch of a steam output pipeline of the steam turbine is connected with the gas inlet end of a low-pressure cylinderof the steam turbine through a second valve group; and the other branch of the output steam pipeline of the steam turbine is connected to the air cooling island through a third valve group and a temperature and pressure reducer which are connected in series, and the temperature and pressure reducer controls the steam quantity transmitted to the air cooling island according to the set steam quantity required by the air cooling island and the environment temperature. According to the invention, the temperature and pressure reducer is arranged to introduce steam in a heat supply output pipeline of the steam turbine into the air cooling island; the amount of steam input into the air cooling island is controlled according to the required steam amount, a closed vacuumizing and condensation watersystem prevents a small amount of steam from leaking into the shutdown air cooling island cooling unit, and freezing damage of the air cooling island during zero-power operation of the low-pressure cylinder can be avoided.

Description

technical field [0001] The present disclosure relates to the technical field related to antifreeze of air-cooled units, in particular, to an antifreeze system and method for an air-cooled island with zero power operation of low-pressure cylinders of direct air-cooled units. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] As the country strengthens the control of environmental pollution, it is necessary to eliminate outdated production capacity and units that do not meet the requirements of relevant mandatory standards, and accelerate the elimination of conventional coal-fired units with a unit capacity below 300MW that have expired in design life and that do not implement heating transformation. Thermal Power. In order to meet the requirements of the national energy conservation and emission reduction policy, increase the competitivenes...

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Problems solved by technology

[0005] The cooling system of the extraction condensing steam unit includes water cooling and air cooling. The extraction condensing steam unit that directly adopts the air cooling of the air cooling island is also called the direct air cooling unit, including the steam turbine connected in sequence, the exhaust device of the steam turbine and the cooling unit of the air cooling island. , the inventor found that after zero-power transformation of the low-pressure cylinder of the direct air-cooling unit, in extreme weather in winter, the cooling steam entering the air-cooling island is greatly reduced, resulting in insufficient heat load of the air-cooling island, and the exhaust steam flow is less than the minimum antifreeze flow at the corresponding temperature, while Frozen air-cooled island

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