Steam turbine circulation part cleaning system and cleaning method

Abstract

The invention discloses a steam turbine circulation part cleaning system and cleaning method. The steam turbine circulation part cleaning system comprises a steam turbine and a steam generator, wherein a generator steam outlet pipe is arranged on the steam generator; a generator steam outlet valve is arranged on the generator steam outlet pipe; a steam turbine steam inlet pipe is arranged on the steam turbine; a steam turbine steam inlet valve is arranged on the steam turbine steam inlet pipe; the generator steam outlet pipe and the steam turbine steam inlet pipe are connected through a steam main pipe; a main valve, an outlet steam pressure gauge and an outlet steam temperature gauge are arranged on the steam main pipe; both the outlet steam pressure gauge and the outlet steam temperature gauge are located at the upstream part of the main valve; a plurality of drain pipes are arranged on the steam main pipe, and drain valves are arranged on the drain pipes respectively; during cleaning of a steam turbine circulation part, the main valve is opened when the steam pressure of the steam generator reaches 3.0 MPa and the steam temperature reaches 235 DEG C, steam impulses the steam turbine to start, and flowing steam washes out scales on an impeller, blades, a partition and a spray nozzle group of the steam turbine.

Description

technical field [0001] The invention relates to the field of steam turbine maintenance in a small thermal power plant, in particular to a steam turbine circulation part cleaning system and a cleaning method which can effectively clean the steam turbine circulation part. Background technique [0002] When a small steam turbine in a thermal power plant is running, under the same operating conditions (same flow rate), the steam consumption, pressure in the monitoring section, and exhaust temperature all increase, especially the pressure in the monitoring section gradually increases to 2.3MPa (0.12 MPa higher than the manufacturer's specification) MPa), and the electric load decreased by about 1000kW. According to the analysis of relevant data and combined with the inspection and overhaul of the unit, it was found that it was caused by salt accumulation in the flow part of the steam turbine. During the inspection and overhaul of the unit, it was found that there were various deg...

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Problems solved by technology

At the same time, due to the large amount of boiler desuperheating water (about 3-4t / h) and the use of mixed water spray cooling, the steam with sodium ions enters the steam turbine. The increase of salt increases the pressure of the monitoring section, which reduces the efficiency and economy of the unit, and also poses a certain threat to safe operation

[0004] The flow part is prone to sodium compound salt scaling, which causes problems such as pressure rise and efficiency drop in the monitoring section. The scaling of the flow part of the steam turbine must be cleaned regularly to avoid the above problems. The current cleaning methods mainly include sandblasting and high pressure. Water flushing, manual polishing, etc. must be carried out in the state of unit overhaul and cylinder removal. The unit overhaul period generally takes 3 to 4 years. The cleaning period is longer and the cleaning cost is higher.

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