Pipeline pressure test issues
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The company's new diesel hydrogenation modification device is about to be completed, and we are working on a pressure test and purge plan for the pipeline. I have a few questions that I don't understand very well, so I'm here to ask for advice.: 1. Can the pipeline hydraulic pressure test be carried out with equipment? Because the equipment hydraulic pressure test pressure is 1.25 times the design pressure, and the pipeline hydraulic pressure test pressure is 1.5 times the design pressure. When carrying equipment for pressure testing, can the pressure be pressurized according to the equipment's hydraulic pressure test pressure? Is there any basis for this? (Requirements of specifications or standards) 2. When the tube side pressure of the heat exchanger is low and the shell side pressure is high, how to determine the water pressure test pressure of the tube side? How to determine the hydrostatic test pressure on the shell side? If the shell side is pressurized, does the tube side need to be filled with water and the pressure raised at the same time? Thank you for your help!
1#kukula_3. There are relevant provisions in the chemical engineering design manual.
1. GB50235 regulations: 7.5.3.6 When the pipeline and equipment are tested as a system and the test pressure of the pipeline is equal to or less than the test pressure of the equipment, the test shall be carried out according to the test pressure of the pipeline. ； When the pipeline test pressure is greater than the test pressure of the equipment, and the test pressure of the equipment is not less than 1.15 times the design pressure of the pipeline, the test can be carried out according to the test pressure of the equipment with the consent of the construction unit. 2. Personally, I feel that the test pressures on the tube side and shell side of the heat exchanger should be conducted under conservative operating conditions. That is, the water pressure on the tube side does not need to be managed on the shell side, and the water pressure on the shell side does not need to be filled with water on the tube side.
In principle, equipment is not allowed for pressure testing on pipelines. If equipment must be used, and the test pressure of the pipeline is equal to or less than the test pressure of the equipment, the test should be carried out according to the test pressure of the pipeline.； When the pipeline test pressure is greater than the test pressure of the equipment, and the test pressure of the equipment is not less than 1.15 times the design pressure of the pipeline, the test can be carried out according to the test pressure of the equipment with the consent of the construction unit. The pipe side and shell side need to be pressed separately. In the situation mentioned by the poster, the pipe side does not need to be filled with water.
It is generally not allowed to carry equipment for pressure testing on pipelines. If equipment is used for pressure testing, the experimental pressure of the equipment must be greater than the experimental pressure of the pipeline. The tube side and shell side of the heat exchanger should be pressurized according to their own design pressures. It is not necessary to fill them with the pressure test medium during the pressure test.
For high-pressure heat exchangers, if the design of the tube sheet has pressure difference requirements, it should be noted that the pressure difference at both ends does not exceed the design specifications.
I don’t know about other equipment. The valves are subjected to shell pressure tests before leaving the factory. The test pressure is 1.5 times the design pressure. The test standard for the valve to be open during the test is API598.