Method for testing air leak rate of air preheater

Abstract

The invention relates to a method for testing the air leak rate of an air preheater, which is easy to implement, accurate and reliable and is suitable for analyzing and testing the air preheater. The accuracy of temperature measurement can reach 0.1 DEG C, the smoke venting temperature is within the range of between 100 and 200 DEG C approximately, and when a boiler runs stably, the smoke venting temperature is constant basically, so the relative accuracy of the temperature measurement is higher than the analytic accuracy of the oxygen content of smoke. Therefore the air leak rate, which is calculated according to the change of the smoke venting temperature, of the air preheater has the higher test accuracy. The method comprises the following steps of: 1) measuring the smoke venting temperature theta py of the air preheater and the temperature TKin of air entering the air preheater; and 2) utilizing a formula, namely when the change of the air leak rate is needed to be monitored due to the change of the air leak rate with the change of the running condition or equipment condition of the air preheater, measuring the air temperature TKin and the smoke venting temperature thetapy in the running state, which corresponds to the temperature thetapy, of the boiler, and calculating the air leak rate AL by the formula.

Description

technical field [0001] The invention relates to a test method for air leakage rate of an air preheater. Background technique [0002] Air preheater (referred to as air preheater) is an important equipment for large boilers. In the air preheater, the flue gas transfers heat to the air, and the temperature of the flue gas decreases after exothermic, leaving the air preheater to become the exhaust gas of the boiler. Large-scale power plant boilers generally use rotary air preheaters. The heat storage element rotates at a certain speed and periodically exchanges heat with flue gas and air. Since the rotation of the heat storage element (rotor) in the rotary air preheater requires a certain dynamic and static gap, and the flue gas in the rotary air preheater is in a negative pressure state, while the air is in a positive pressure state, therefore, there will be Part of the air leaks into the flue gas and exits the air preheater with the flue gas. The air leakage rate of the ai...

AI Technical Summary

Problems solved by technology

The implementation of this test method is relatively complicated, requiring special instruments, and because the flue gas composition (such as oxygen content, etc.) may fluctuate greatly during boiler operation, it has strict requirements on the operating state, which also affects the test. accuracy of results

Because the on-line instrumentation of flue gas oxygen content has a certain measurement lag, using on-site on-line instrumentation to estimate the air leakage rate sometimes brings large errors

In addition, the resolution of the oxygen analysis instrument is generally 0.1% of the oxygen content, and the oxygen content of the flue gas is generally about 5% to 7%, so the relative accuracy of the oxygen measurement is about 2%, which also affects the air preheating. Test accuracy of air leakage rate of heater

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