Steam pipeline purging plan

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I. Safety Precautions: 1. It is strictly prohibited to stand under the one-way drain valve for pipeline drainage. 2. There is no one within a 1-meter diameter radius around the outlet of each hydrophobic point’s drain pipe. 3. There is no one within 50 meters in the direction of the outlet of the main export valve. 4. Purging must be carried out only after receiving orders from the construction supervisor. 5. Maintain smooth communication. 6. The operator must wear safety gloves. II. Purging procedure: The purging command is issued by the chief commander. 1. Before purging, the persons in charge of each area shall carry out the following tasks: 1) Check whether the supports are damaged. 2) Open the primary direct-through valves, primary bypass valves, and secondary bypass valves for each drain line on the pipeline, and close the shut-off valve before the trap. 3) Keep original records and markings for all sliding supports; document the expansion that occurs during pipe heating, and observe the condition of the fixed supports while keeping records of that as well. 4) Open the purge outlet valve slightly. 2. Slowly open the steam supply valve to warm up the steam supply pipe, and check the drainage at each drain point as well as the operation of the compensators and supports. To learn about boiler knowledge, please follow the WeChat official account Boiler Circle. 3. After confirming that all inspections show no abnormalities, report to the chief commander, then slowly open the steam supply valve again to further warm the pipes; check each drain point along the pipeline one by one until there are no obstructions in the direct-through valve of drain point No. 1, after which close the main steam valve. 4. For pipeline steam traps, close the direct-through valve once after steam drainage is completed. 5. After confirming that all the one-way drain valves on the pipelines are closed, report to the chief commander. 6. Slowly open the main steam supply valve again to heat the pipes; the heating time is 20–30 minutes. Check each drain point along the pipeline one by one, and once no water more flows out of the secondary bypass valve at drain point #1, close that secondary bypass valve. 7. After completing the warm-up of the pipes, close all drain valves. 8. Gradually increase the pressure to 0.80 Mpa and maintain it for 20 minutes. 9. After voltage stabilization is complete, slowly open the temporary outlet control valve to gradually increase the flow rate to 30 m/s, and purge for 20 minutes. 10. After the purging is complete, close the temporary outlet control valve, place a warning sign, replace the blind flange, open the drain, and wait for the next purging cycle. 11. Wait until the pipe wall temperature drops below 100°C and the pressure reaches 1.5 Mpa before carrying out the aforementioned purging steps (1–7) (the primary drain bypass remains closed). To learn more about boiler knowledge, please follow the WeChat official account “Boiler Circle”. Ensure that the gasket is flat and the blind flange is positioned correctly; then observe how impurities accumulate on the blind flange. The process is considered complete once the inspection of the blind flange yields satisfactory results. 12. After the purging is complete, remove the temporary connection. 13. Organize the records and submit them to the commander and the chief commander. III. If any of the following faults are detected during purging, they must be reported to the chief commander immediately, and the purging process should be stopped. 1. The pipeline ruptured over a large area, resulting in a massive release of steam. 2. Large-scale displacement of the support and the pipeline being pushed away from the support. 3. Severe water hammer occurs in the pipeline. IV. Precautions during purging: 1. During the purging process, it is necessary to maintain close communication with the control room staff in order to regulate steam pressure and temperature. 2. Special care should be taken during the first purge, to prevent the backpressure from disrupting the stability of the piping system. The purge control valve should be opened slowly, and close attention should be paid to the conditions at the outlet of the purge pipe. If any abnormalities occur, the purge control valve must be closed immediately; only after the abnormality is resolved can the purge process be resumed.