Purging and flushing plan for the initial startup of raw gas shift

Before starting up the conversion system, it should be purged and flushed with an inert gas (N₂ or a suitable inert gas), as this is necessary for safety. Flushing and cleaning with gas is dangerous and can lead to explosion accidents.

This post was last edited by 654262293 on 2010-9-9 at 10:33. 1. For the purging of process gas pipelines and equipment, compressed air is generally used; steam pipelines are purged with steam, so no pollution is released into the atmosphere. 2. For water circulation pipelines, desalination water pipelines, boiler feedwater pipelines, etc., water flushing is commonly used; during flushing, the water is discharged into gutters and sent to a sewage treatment facility for centralized treatment. 3. Equipment that can be cleaned manually must be cleaned manually again. 4. The purging sequence should follow the order of main pipes, large-diameter pipes, branch pipes, drain pipes, and instrument pressure guide pipes, from near to far; each system’s branch pipes should be purged separately. 5. Purging of the control valve assembly: First, disconnect and purge (wash) the areas in front of the manual valve of the inlet valve assembly as well as in front of the bypass valve. Then, replace the control valve with a short section to carry out purging (washing); the bypass and drain lines should also be purged (washed). 6. Purging of individual pump units: Disconnect the front flange of the pump or the front section of the pump body, flush the inlet pipeline, and then install a temporary filter on the inlet pipeline (or use the filter that is already present in the pipeline). Remove the flow control orifice plate from the return pipeline as well as disconnect the front flange before the equipment, and then start the pump to flush the return pipeline. 7. When the purging medium is to pass through the equipment, the upstream pipeline connected to the equipment must first be purged thoroughly to prevent debris from entering the downstream pipelines and equipment. If it is difficult to leave a purge port before entering the stationary equipment, depending on the convenience of cleaning, the purge medium can be introduced into the equipment, and the equipment must be cleaned. 8. It is used to purge (flush) utility pipelines with the fluid it transports as a cleaning medium. 9. After purging the pipeline, it should be restored immediately to prevent yarns, debris, and other substances from entering the pipelines, control valves, and flow meters ； At the same time, to create conditions for the next purge. 10. Criteria for completing the purging: Water flushing is considered successful when the color and transparency of the water at the outlet are visually consistent with those of the water at the inlet ； For air purging, a white cloth or gauze should be placed at the exhaust outlet for target testing, and the process should continue until no dirt is detected on the cloth or gauze.

It’s too general; basically, all chemical purging and flushing operations are carried out following this approach. It would be better if it could be more detailed

This post was last edited by 654262293 on 2011-2-23 at 16:39. Different processes require different methods for purging and flushing; there are many types of transformations, such as medium-temperature transformation, medium-to-low transformation, medium-low-low transformation, full-low transformation, and sulfur-tolerant transformation with high pressure and high water vapor ratio. Even for the full-low transformation, there are processes that use saturated hot water towers and those that do not. How can I know what your process is? Even if I gave you my solution, what’s the use if it differs from your process? Since you don’t have a flowchart, I can only tell you the principles of purging and flushing, and guide you on the approach.

For the conversion system, the general approach is to first blow air through the area (by tapping on the welds), then vent the air and remove any contaminants. After blowing, the effectiveness of this process can be checked by using a white cloth at the outlet where the air is blown. Next, inert gas is used for displacement, and samples are taken to analyze the oxygen content; afterwards, gas is used for displacement as well – as long as there is gas flow, that’s sufficient. For the degassing system, clean water is injected and circulation is initiated to identify any leaks, after which the dirty water is removed