Leakage of superheater system of the hottest circu

2022-07-29
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The leakage of circulating fluidized bed boiler superheater system

Shanxi Houma Jintian Thermal Power Co., Ltd. has two 50MW coal-fired power generating units, which have adopted advanced environmental friendly circulating fluidized bed boiler technology and have been put into operation in December, 2002

since the unit was put into operation, the operation of the unit has been relatively stable. Although the boiler was shut down for several times, it was caused by the failure of auxiliary equipment and the poor slag discharge system. However, the superheater leakage that is difficult to find and judge has occurred successively in and

t 20:00, the stoker of No. 1 boiler found that the flue gas temperature difference at the inlet and outlet of cyclone separation was nearly 60 ℃, and the shift leader immediately organized the stoker and assistant stoker to analyze this abnormal situation, and arranged the patrol inspectors to conduct a comprehensive inspection. Two steam cooled separators with a diameter of about 5m are used for the two circulating fluidized bed boilers of Jintian thermal power, which are arranged between the combustion chamber and the tail convection flue. The outer wall is made of model wall and is used as a part of the superheater. In other words, only the leakage of superheater may lead to the increase of flue gas temperature difference at the inlet and outlet of cyclone separator. The curve chart of China's production history of plastic packaging materials on the CRT screen shows that the smoke temperature difference began to rise little by little two days ago, but the trend was relatively balanced. By 19:00 on the 18th, the curve suddenly rose from about 40 ℃ to nearly 60 ℃ when the stoker attracted attention. Check the steam water flow, differential pressure of saturated steam and superheated steam and induced draft fan current again, and there is no obvious change before 19:00. Since 19:00, the opening of the inlet baffle of the induced draft fan has increased by 20%, the current has increased from 22 A to 24 A, the exhaust gas temperature has increased abnormally, and the feedwater flow has also increased. Therefore, it is judged that the superheater in the cyclone separator is leaking. At this time, the inspectors returned to the aluminum powder industry: the policy supported the development of high-end products, and no abnormality was found. In order to make an accurate judgment, the stoker and the team leader went to the scene to check. As expected, no leakage sound was heard and no abnormality was found. The team leader and the stoker analyzed again and thought that the fluidized bed boiler was a positive pressure boiler, without inspection hole, and it was normal that no leakage sound could be heard, and the change of other parameters could explain the problem. Therefore, the boiler shall be shut down immediately in consideration of the purchase cost

after boiler shutdown, three superheater tubes leaked, stabbing the nearby anti-wear casting material, and more than a dozen tubes were damaged to varying degrees

in view of this lesson, the monitor organized the whole class to carefully analyze and summarize. The new furnace type has new characteristics. Only by paying enough attention to every small change can we better master it

at t10:00, the stoker of No. 2 boiler found that the flue gas temperature difference of the separator on the left side of No. 2 boiler had increased from more than ten degrees to more than twenty degrees, and immediately reported it to the team leader. The team leader first contacted the thermal engineer to detect the main causes of the meter recording, which were measured hollow out parts, thin plates and soft metal materials. After confirming that the meter recording was correct, the team leader made a decisive judgment on the leakage of the superheater in the separator according to the extremely small changes in other parameters. At the same time, he reported it and applied for shutdown

the inspection afterwards proved that the judgment of the stoker and the monitor was very accurate and timely

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