A deep heating cold end system for direct air cooling units

Abstract

The invention discloses a deep heat supply cold end system of a direct air cooling unit, which relates to the technical field of the cold end of a steam turbine direct air cooling unit in a thermal power plant; it includes a low pressure cylinder, an exhaust device, a cooling water spray mechanism, an air cooling island and an air cooler The power tower, the exhaust device is connected to the exhaust outlet of the low pressure cylinder, the cooling water spray mechanism is arranged in the exhaust device, so that the cooling water can exchange heat with the exhaust steam in the exhaust device and form condensed water, and the air cooling island passes through The exhaust pipe is connected to the exhaust device, so that the exhaust steam in the exhaust device can be discharged into the air cooling island for cooling. An exhaust valve is arranged on the exhaust pipe, and the air cooling tower is connected to the exhaust device through the drain pipe. , so that the condensed water in the exhaust device can be discharged into the air-cooled power tower for cooling; through the implementation of this technical solution, it can effectively solve the problem of maintaining the low back pressure of the unit during the deep heating period and prevent the air-cooled island from appearing The risk of icing can effectively enhance the safety and reliability of the unit.

Description

technical field [0001] The invention relates to the technical field of the cold end of a direct air cooling unit of a steam turbine of a thermal power plant, in particular to a deep heating cold end system of a direct air cooling unit. Background technique [0002] In conventional thermal power direct air-cooled units undergoing deep heating transformation such as low-pressure cylinder cutting, micro-output, zero-output, etc., although the exhaust volume of the low-pressure cylinder is very small, it is also necessary to maintain the low back pressure of the steam turbine to reduce the final blade of the steam turbine. The risk of over-temperature of the blade brought by the blast, at the same time, the recovery is subject to some system leakage and the guarantee of the hydrophobic pressure difference. [0003] In the operation of the existing steam turbine, the exhaust steam of the steam turbine is condensed by entering the air-cooling island. Although the air-cooling islan...

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Problems solved by technology

[0005] Technical solution 2 adopts a newly added surface heat exchanger, and the steam drawn from the outlet steam pipe of the exhaust device is condensed in the external condenser; for example, the patent with the publication number CN109469522A discloses a exhaust steam cooling system and exhaust steam cooling system. Method, by setting a pipe connected to the inlet of the exhaust steam cooler on the exhaust pipe from the exhaust steam of the steam turbine to the air cooling island, during the zero output operation of the low pressure cylinder of the direct air cooling unit in the winter heating season, the steam distribution of the air cooling condenser is closed. All steam inlet valves are piped, the air-cooled condenser is isolated, and all the exhaust steam of the steam turbine unit is introduced into the exhaust steam condenser for condensation. The cooling water source is taken from the auxiliary cooling water system of the unit, and the condensed water is returned to the exhaust device of the main engine, completely solving the problem of direct air cooling The freezing problem of the air-cooled condenser during the heating operation of the low-pressure cylinder with zero output in the heating season of the unit; however, this solution has the following technical defects: due to the low steam pressure and large specific volume, the exhaust steam extraction pipeline is very large, the pipeline layout and civil engineering design The construction is difficult. At the same time, the circulating water of the condenser needs to be taken from the closed cooling water system or an independent closed circulating water system is installed. Usually, the direct air cooling unit area is seriously short of water. This solution needs to increase a large amount of circulating water, which is not conducive to water saving. And the system pipeline is complex, the failure rate is high during operation, and the investment is large

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