Chemical cleaning system and method for oxide skin of power station superheater or reheater

Abstract

The invention relates to a chemical cleaning system and method for the oxide skin of a power station superheater or reheater. The system comprises a cleaning power platform, wherein the cleaning power platform is connected with the system inlet of the power station superheater or reheater through a liquid inlet pipeline, and is connected with the system outlet of the power station superheater or reheater through a liquid returning pipeline, so that circular cleaning is realized for the power station superheater or reheater; corrosion on-line monitoring equipment and a heater are arranged on the liquid inlet pipeline; the corrosion on-line monitoring equipment is used for monitoring the corrosion rate of the superheater or reheater in real time during a chemical cleaning period, so that excessive corrosion of the superheater or reheater is prevented; the heater is used for heating cleaning liquid; dead-end pipe on-line monitoring equipment which is used for monitoring the pipe flowing state of the superheater or reheater in real time is arranged in the pipe of the power station superheater or reheater; and the invention further discloses the cleaning method. By using the system and method disclosed by the invention, the oxide skin of the power station superheater or reheater is completely removed; pipe bursting risk is lowered during the operation period of the power station superheater or reheater is lowered; and meanwhile, the heat conduction efficiency of the power station superheater or reheater is improved, so that safe and economical operation of a power station is ensured.

Description

technical field [0001] The invention relates to the field of scale removal for superheaters and reheaters of power stations, in particular to a chemical cleaning system and method for scales of superheaters or reheaters of power stations. Background technique [0002] The technical level of thermal power generation in my country continues to rise, the parameters of the unit are getting higher and higher, and the higher steam temperature is more demanding on the material requirements of the superheater and reheater of the power station. At present, the superheater and reheater are mainly 12CrMoV, T22, T91, TP347H And Super304 material mainly. With the prolongation of the operation time of the superheater and reheater of the power station, the growth of scale is inevitable under the high temperature oxidation of the superheater and reheater tubes. Oxide skin will reduce the heat transfer efficiency during the operation of the superheater and reheater of the power station; at t...

AI Technical Summary

Problems solved by technology

Among them, the pipe cutting cleaning method can only remove the scale that has peeled off, and cannot avoid the peeling of the scale during the start-up process. The reliability of this method is low; the outstanding problem of the pipe replacement method is the high cost, which is 6 times that of chemical cleaning. Above, less economical

[0003] Compared with the chemical cleaning of economizers and water walls, the chemical cleaning of superheater and reheater scales has the following difficulties: 1) The scale of superheaters and reheaters is very dense and cannot be completely removed by conventional chemical cleaning techniques; 2) overheating There are many types of tube materials for superheaters and reheaters, and it is necessary to ensure that the corrosion of all materials is controllable. Austenitic stainless steel needs to strictly control pitting corrosion and intergranular corrosion; 3) superheaters and reheaters are mostly W-shaped structures, and gas plugs and plug 4) When cleaning different materials at the same time, it can not only ensure the complete removal of low-chromium alloy steel scale, but also retain the chromium-rich layer of austenitic stainless steel, so as to delay the growth rate of austenitic stainless steel scale

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