Pressure testing of chemical pipelines
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When is water and when is air used for pressure testing of chemical pipelines?
I remember that water was used during the leak testing, while air was used during pressure testing; finally, gas was used for the last leak check, along with soap water and similar substances
Generally, water is easier to use for pressurization and is safer; using air is more difficult, as it’s hard to find equipment capable of delivering air at such high pressures. So it’s better to use water.
Pressure pipeline testing should use liquid as the test medium. When the designed pressure of the pipeline is less than or equal to 0.6 MPa, gas can be used as the test medium, but effective safety measures must be taken. After that, purging and water flushing are carried out, followed by another airtightness test. As the friend from the second group put it: air is introduced to pressurize the equipment, with the pressure being increased gradually and in stages during the testing for leaks; soap water is used to check for leaks at each weld.
Water is generally used for pipeline pressure testing; air is only employed for pipelines where water cannot be used. Relevant **standards** can be referred to for this purpose.
Under normal circumstances, water pressure testing (strength test) is used, as well as vacuum pumps (negative pressure) for airtightness testing; the gas is then replaced and dried
Generally, it refers to the hydrostatic test strength for water and the airtightness test for air. Relevant specifications can be referred to. Most equipment comes with pressure testing results; you can refer to the pressure curve from those tests.
Gas is used for the reactor, while water is used for the column equipment.
You can refer to HGJ231-91
Even when using gas, it is best to use nitrogen, as inert gases have a much lower likelihood of exploding
Moreover, stamping should be done in stages, without applying a high pressure all at once! You can choose a weight of half a kilogram each time! After each pressure increase, check for any leaks at the welds or any deformation of the pipes!
Pneumatic testing generally uses air instead of nitrogen. In terms of the level of explosion danger, the two are the same. From a comprehensive safety perspective, air is safer than nitrogen; pure nitrogen is toxic. When people are in an environment filled with pure nitrogen, they can still get poisoned even if they wear breathing masks, as nitrogen has a high degree of permeability and can replace the oxygen in the blood through human pores, resulting in oxygen deficiency. ) is more dangerous. For ease of operation and economic reasons as well, air is more suitable. Nitrogen is commonly used to purge pipelines carrying flammable media during maintenance. This post was last edited by zhanong on 2007-12-23 00:52]
Some comrades are not very clear about certain issues; please don’t mislead everyone here, will you? Show some morality
Generally, water is used first, and then air pressure, as air pressure poses a greater risk
During pressurization, gas is used for testing, usually on low-pressure pipelines. If a problem does occur, the pressure must be reduced slowly using gas, whereas it can be reduced much more quickly with liquid. Water is incompressible, so that should be clear. Additionally, some factors depend on what is connected to the pipeline downstream; for example, if it leads to equipment such as towers that contain catalysts, then water cannot be used and gas must be employed instead. In such cases, it depends mainly on the characteristics of the equipment
First, conduct a hydraulic test to check whether it reaches the design pressure, and then perform a pneumatic test to verify its airtightness.
Chemical process pipelines are generally subjected to pressure testing using water, and the requirements for this water depend on the material of the pipeline. When conducting experiments with gases, it is necessary to do so in accordance with the properties of the gas in the pipeline (as specified in the design documents for gases such as gas, phosgene, ammonia (liquid), etc.), but a hydrostatic test must also be carried out first. As stated on floor 12. Nitrogen is generally used for leak testing of containers (categories 2 and 3). It is used in combination with air, typically at around 30%.
Thank you all; I have learned so much here
Generally, water pressure is used; where water pressure is not suitable, air pressure is employed, and care must be taken to ensure safety when using air pressure
1. When water is chosen as the pressure testing medium, it should be taken into account that stainless steel pipes have specific requirements regarding the chloride content in water; this level should not exceed 25 ppm. 2. The decision of whether to use water or gas should be based on the design specifications, and the pipe specifications can be consulted for reference purposes in pressure testing.
For processes where water is not allowed in the process medium, pressure testing with water cannot be used; for all other cases, water can generally be used. Be sure to pay attention to safety when performing pressure testing with gas. It is specified in the \"Code for Construction and Acceptance of Industrial Metal Piping\"