Verification and calibration method for oxidation rate of high-temperature heating surface of supercritical thermal power generating unit

Abstract

Disclosed is a verification and calibration method for the oxidation rate of the high-temperature heating surface of a supercritical thermal power generating unit. The verification method comprises the steps that a, verification and calibration in the operating period are conducted, specifically, whether the oxidation rate abnormity is synchronous with the overtemperature of the wall temperature or not in the operating period is verified and calibrated, the wall temperature is qualified after operating adjustment, and whether the corresponding oxidation rate is normal or not is verified and calibrated; b, verification and calibration of on-site inspection in the maintenance period are conducted, specifically, the oxide skin stripping and pipe blocking situations are inspected through the means of magnetographic inspection, endoscopic inspection and the like, and whether the oxidation rate confirms to the oxidation rate monitoring result or not is verified; c, verification and calibration of oxide skin detection in the maintenance period are conducted, specifically, an oxide skin sample and a blocked pipe sample are subjected to X-ray diffraction analysis, scanning electron microscope analysis and optical metallographic microscope analysis, thus the oxide skin forming, growing and stripping mechanisms and rules are verified, and the oxide skin prevention measures are put forward; and d, an oxidation rate monitoring model is verified and calibrated through the steps a, b and c step by step, and thus the oxide skin treatment measures are finally perfected.

Description

technical field [0001] The invention relates to a method for verifying and calibrating the oxidation rate of a high-temperature heating surface of a supercritical thermal power generating set, and belongs to the technical field of supercritical thermal generating set high-temperature oxide scale treatment. Background technique [0002] In recent years, the scale problem of superheater materials in supercritical units has become more prominent. Due to the rapid and massive formation of scales in superheaters and reheaters, when the load of the unit fluctuates violently, it is easy to cause a large number of scales to peel off, causing pipe plugging Excessive temperature and pipe burst have become a major safety hazard affecting the safe operation of the unit. The high-temperature oxidation rate of the unit has always lacked the means of online monitoring. The data show that a lot of research work has been carried out on the oxidation law of superheater materials by high-tempe...

AI Technical Summary

Problems solved by technology

[0002] In recent years, the scale problem of superheater materials in supercritical units has become more prominent. Due to the rapid and massive formation of scales in superheaters and reheaters, when the load of the unit fluctuates violently, it is easy to cause a large number of scales to peel off, causing pipe plugging Excessive temperature and pipe burst have become a major safety hazard affecting the safe operation of the unit

The high-temperature oxidation rate of the unit has always lacked the means of online monitoring. The data show that a lot of research work has been carried out on the oxidation law of superheater materials by high-temperature water vapor at home and abroad, but all of them are theoretical studies in the laboratory, and the scale formation rate is lack of monitoring. The method and data accumulation, the growth principle and influencing factors of oxide scale lack experimental demonstration, and it is impossible to predict and judge the high-temperature oxide scale risk area on the high-temperature heating surface during the operation of the unit. Carry out real preventive maintenance work, and many units even have a large amount of scale peeling off again during the start-up period after the maintenance, which may cause over-temperature and load drop in light cases, and cause shutdown in severe cases

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