Steam purging plan for the compressor inlet steam pipeline

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This post was last edited by Small and on 2017-8-27 20:10. J0201 Imported Steam Pipeline Steam Purging Plan 1. Overview: Since the J0201 turbine has not been in operation for a long time, steam purging will be carried out on the imported steam pipeline prior to starting up the unit, in order to remove rust, oil, and other debris from within the pipes. This prevents blockages in the equipment and pipelines, thereby creating favorable conditions for the commissioning and startup of the J0201 turbine, and ensuring that its commissioning and startup are successful on the first attempt. 2. Basis for preparation: a. The production preparation outline issued by the control room; b. *****PID flowchart; c. General regulations for pipeline cleaning and purging. 3. Organizational structure **** 4. Safety risk analysis and preventive measures 4.1 Safety risk analysis 4.1.1 Operators are exposed to safety risks such as burns from high temperatures, pressure-related injuries, noise-induced harm, falls from heights, object strikes, and mechanical injuries during the purging process. 4.2 Preventive Measures 4.2.1 The operation plan shall be approved and issued; process operators must pass training and assessment, and the purging plan shall be strictly followed. 4.2.2 Operators must wear proper personal protective equipment. 4.2.3 The purging exhaust outlets must be strictly managed, with a dedicated person in charge, safety fences and warning signs installed, and dedicated personnel assigned to oversee them in order to prevent unexpected incidents; unauthorized persons are strictly prohibited from entering the purging area. 4.2.4 Personnel participating in the purging process must be familiar with the system’s operational procedures, obey assignments and instructions, remain at their posts, and coordinate with one another. 4.2.5 Operators must strictly follow the process operation procedures and safety technical regulations. 4.2.6 Before purging, check the reliability of the pipeline supports; temporary pipelines should be thoroughly inspected to confirm whether their reinforcement is adequate, and to check for any possibility of leakage or displacement. 4.2.7 During purging, the steam pipes must be thoroughly warmed to prevent severe vibration of the pipes and their supports. 4.2.8 No other process operations or maintenance work are permitted during the purging process. 4.2.9 To control the noise generated by purging and prevent disturbance to residents, a steam silencer is installed at the outlet pipe, ensuring that the silencer is effective and securely fixed. 5. Purging methods and key points 5.1 The pipeline to be purged is: the steam pipeline network at 2.6 MPa leading to the steam inlet in JT-0201 (12SM005156P2D). 5.2 In accordance with the general guidelines for pipeline cleaning and purging, since the inlet pipeline is short, it is not necessary to perform air purging first; only steam purging is carried out. 5.3 To prevent impurities from being carried into other pipes and equipment in the steam system during purging, the inlet pipeline is purged separately. 5.4 The purging method for steam pipelines is repeated using intermittent purging until the purging is satisfactory. By repeating this process, deposits such as rust on the inner wall of the tube are made to fall off more easily; each cleaning session lasts about 10-20 minutes, with a interval of 10-20 minutes between sessions. Alternatively, cool the pipe to half of the maximum temperature during steam purging, and repeatedly strike the weld with a hammer at intervals. Number of times the pipeline is purged: 6–8 times for main pipes, and 4–6 times for branch pipes. The purge speed should be 30 m/s; otherwise, adjust the flow rate of the purge steam to ensure proper purging of the pipeline, so that the disturbance coefficient C is greater than 1. The formula for calculating the flow rate is as follows: omitted. 1 – Density of the purge medium; V1 – Speed of the purge medium. 2 – Normal density of the flowing fluid; V2 – Speed of the flowing fluid under disturbed conditions. 5.5 Before using steam for purging, it is necessary to thoroughly warm the pipeline, and attention must be paid to drainage to prevent water hammer effects. 6. Preparations before purging 6.1 Confirm the steam pipeline layout and prepare a hammer. 6.2 Since steam purging is carried out separately on the inlet pipelines, it is necessary to ensure that the flanges at the ends of these pipelines have been removed before introducing steam into the steam system. Pipes for steam purging must be properly installed, and silencers should be placed at the ends of the temporary exhaust pipes to control the discharge of steam or other substances. Clear signs must be placed in place to prevent people from being injured by steam or the discharged materials. A designated person shall be responsible for this process, and access by pedestrians is strictly prohibited. (The temporary discharge pipe installation point is shown in the figure). 6.3 Verify that the purging pipeline is isolated from adjacent piping and equipment with blind plates in place ； For pipelines with control valves and instrumentation components, ensure that these control valves and instrumentation components have been removed for protection and replaced with bypasses; they should be reinstated once the purging is complete. 6.4 The steam pipeline network has been warmed up, and steam at 2.6 MPa has been introduced into the network. Heat electric steam to establish pressure in the steam system (calculated based on a pressure of 1.0 Mpa in the pipeline downstream of the valve). During the steam introduction process, the speed should not be too high (steam flow rate: ≥15 T/h). The process of establishing pressure in the steam system is also a process for testing and checking for leaks in the pipelines. 7. Purging operations 7.1 Pipeline purging: Steam pipeline network at 2.6 MPa to the steam pipeline in JT-0201 (12SM005156P2D). 7.2 Warm pipes. A small amount of 2.6 MPa steam is introduced gradually to preheat the steam pipeline, raising its temperature and allowing the pipeline to expand smoothly. Prevent sudden increases in pipe temperature from causing excessive local stress and damaging the pipe. Also pay attention to hydrophobicity to prevent water hammer. 7.3 Pressure building: Gradually open valves A1/B1 on the purging pipeline to increase the pipeline pressure, and perform intermittent purging of pipeline 12SM005156P2D. The pipeline is pressurized; once the pressure has risen to approximately 2.6 MPa, valves A1/B1 are opened for purging. Once the pressure drops, valves A1/B1 are closed and the pressure is raised again. This process of purging is repeated, with the number of times of purging determined based on the conditions on site. 7.4 After purging for a certain period of time, close the end valve, place the monitoring plate (after valves A1 and B1), open the valve to check the quality of the purge; each purge should last 15 minutes. Then close the end valve and inspect the target plate until no rust is present on it. 8 The acceptance criteria for purging are in accordance with the requirements of the national standard GB50235-97: Steam pipelines should be purged using high-flow steam, with a flow rate of not less than 30 m/s. The purging flow rate is calculated based on the diameter of the pipes in question. For the steam pipeline leading to the compressor, after steam purging, the test target shall be inspected, and its quality must meet the specified requirements. Project Quality Standards: Marks on the wafer should have a diameter of ∮0.6mm or less; the depth of these marks should be less than 0.5mm. There should be 5 particles per cm2. The processing time should be 15 minutes (both attempts must meet these criteria). Attachment: Schematic diagram of the steam pipeline cleaning process: file:///C:/Users/app/AppData/Local/Temp/msohtmlclip1/01/clip_image006.gif