Steam heater No. 1 for flue gas whitening treatment at Shaanxi Chemical Industry has been successfully repaired to stop leaks

Thread Content

Leak fixed in Steam Heater No. 1 for Flue Gas Whitening at Shaanxi Chemical Industry Company – Author/Source: Shaanxi Chemical Industry Company; Date: 2022-06-13; Clicks: 22. At around 16:00 on June 11, the leak at the inlet of Module B of Steam Heater No. 1 used for flue gas whitening at Shaanxi Chemical Industry Company’s power plant was successfully repaired, and the heater resumed normal operation at 17:00. At 9:00 on June 10, while the major maintenance of Boiler No. 3 was in full swing, a sudden leak occurred at the steam inlet valve of Steam Heater No. 1 for flue gas desulfurization. Immediately, steam filled the area around the heater, and hot water sprayed out from the flue of Boiler No. 1; as a result, Steam Heater No. 1 had to be shut down urgently. The flue gas whitening system is equipped with two sets of steam heaters, which are the heat exchange devices at the very end of this system. Their main function is to exchange heat with the flue gas using 0.5MPa steam, thereby raising the temperature of the flue gas emissions, reducing or eliminating flue gas trails, and improving the quality of the flue gas emissions. Currently, due to the shutdown for maintenance of Boiler No. 3, the Flue Gas Cooler No. 3, the Flue Gas Reheater No. 2, and the Steam Heater No. 2 are out of service. The operational status of the Steam Heater No. 1 has a direct impact on the quality of flue gas emissions. Upon hearing the news, the on-duty staff and technicians rushed to the site to locate the leak. Since the location of the leak was quite hidden, situated behind the insulation at the inlet valve of Module B, it was difficult to determine its exact position, which posed challenges for fixing the leak. The technical personnel present immediately contacted the unit responsible for insulation work at the site to remove the insulation from the area where the leak was present. After repeated attempts to detect and repair the leak, it was found that the metal expansion joint at the inlet of Module B of Steam Heater No. 1 was damaged, resulting in significant steam leakage during operation. In order to eliminate the leakage as quickly as possible and restore the operation of Steam Heater No. 1, the branch plant, in the absence of spare expansion joints, made the decisive decision to isolate Module B using blind flanges at its inlet and outlet valves, thereby shutting down Module B and bringing Modules A, C, and D online, so as to ensure the proper operation of the heater and maintain the quality of exhaust gas emissions. Once the plan was finalized, the technical staff at the branch plant promptly handled the procedures to obtain the blind plate permits. Meanwhile, the maintenance crew began preparing the blind plates while removing the flanges from the inlet and outlet valves. After two hours of hard work, Module B of Steam Heater No. 1 was successfully isolated. At around 16:00, Steam Heater No. 1 began to introduce steam at 0.5 MPa to warm the pipes and raise their temperature; at 16:50, Steam Heater No. 1 started operating normally, and the temperature of the flue gas emitted from the chimney returned to its normal levels.