Can the safety valve be installed like this?

Personally, I think it is not possible because it involves the issue of the maximum working pressure, and the sealing test pressure of the safety valve is related to the maximum working pressure.

In the reply above, please come up with specifications or standards, because the pressure vessel training books used by equipment operators only try to make the pipes as short as possible and reduce elbows. I personally think this is not possible, and they asked me to come up with standards.

Safety valve installation requirements The safety valve installation requirements are as follows: 1. The safety valve should be installed vertically, and should be installed in the gas phase space above the liquid level of the pressure vessel, or on the pipeline connected to the gas phase space of the pressure vessel. 2. The cross-sectional area of ​​the through hole of the connecting pipe fitting between the pressure vessel and the safety valve shall not be less than the inlet cross-sectional area of ​​the safety valve, and the connecting pipe shall be as short and straight as possible. 3. When two or more safety valves are installed on a connection port of a pressure vessel, the inlet area of ​​the connection port should be at least equal to the sum of the inlet cross-sectional areas of these safety valves. 4. It is generally not suitable to install a stop valve between the safety valve and the pressure vessel. In order to achieve online calibration of the safety valve, a bursting disc device can be installed between the safety valve and the pressure vessel. For pressure vessels containing extremely, highly, or moderately toxic media, flammable media, corrosive, viscous media or precious media, in order to facilitate the cleaning and replacement of the safety valve, a stop valve can be installed between the safety valve (bursting disc device) and the pressure vessel only with the approval of the technical person in charge of the safety of the pressure vessel of the user unit and the establishment of reliable preventive measures. During normal operation of the pressure vessel, the stop valve must be fully open (sealed or locked). The structure and diameter of the stop valve should not hinder the safe discharge of the safety valve. 5. The installation location of the safety valve should be convenient for inspection and maintenance.

Key points for the installation of safety valves and their pipeline layout design: 1. Safety valves should be installed upright and close to the equipment or pipelines being protected. If it cannot be arranged close, the total pressure drop in the pipeline from the protected equipment or pipeline to the safety valve inlet should not exceed 3% of the fixed pressure value of the safety valve. 　　2. The safety valve should be equipped with a maintenance platform. When arranging a heavy safety valve, the possibility of lifting the safety valve after disassembly should be considered, and a boom should be installed if necessary. 　　3. The inlet pipe of the safety valve should use a long radius elbow. 　　4. The design of the safety valve outlet pipeline should consider that the back pressure does not exceed a certain value of the safety valve's fixed pressure. For ordinary spring-type safety valves, the back pressure does not exceed 10% of the fixed pressure value of the safety valve. 　　5. When the medium discharged into the vent main pipe or the flare main pipe contains condensate or condensable gas, the outlet of the safety valve should be higher than the main pipe. ； Otherwise, drainage measures should be taken. 　　6. The outlet pipe of the safety valve discharged into the closed system should be connected at a 45° angle to the top of the discharge main pipe along the direction of the medium flow to prevent the condensate in the main pipe from flowing back into the branch pipe and reduce the back pressure of the safety valve. 7. When there is a cut-off valve on the safety valve inlet and outlet pipe, a single-gate gate valve should be used and lead-sealed. The valve stem should be installed horizontally to prevent the valve plate from sliding down when the pin connecting the valve stem and the valve plate is corroded or loosened. When the safety valve is equipped with a bypass valve, the valve should be sealed and closed.

1. The installation location of the safety valve should be convenient for inspection and maintenance. 2. When the vented medium contains condensate or condensable gas, the outlet of the safety valve should be higher than the main pipe ； Otherwise, drainage measures should be taken. 3. If the vented medium does not contain condensate or condensable gas, the safety valve can be piped to the lower part.

Just to add: The above is stipulated in the "Capacity Regulations", and it is 152. Look at the red font, yours is a gas tank, so you can install it underneath (not near the inlet and outlet) or lead a pipe down to install a safety valve. This post was last edited by gzk1986 on 2009-3-11 15:14 ]

Personally, I think the key to the problem lies in the original design. As mentioned on the 5th floor, "The safety valve should be equipped with an inspection platform." If there is an inspection platform, there will be no subsequent problems.； If you have to change it to the lower part of the container (although this installation method is very rare), you need to pay attention to the pressure drop changes caused by changes in the safety valve inlet pipeline (piece) and outlet pipeline (piece). You cannot just move the safety valve to the bottom. In other words, the safety valve needs to be recalculated.

The core of this problem is that the pressure difference in the inlet section of the safety valve cannot exceed a value of constant pressure. Can't remember clearly. , as long as it is satisfied. And if there is no accumulation of liquid at the entrance, there will be no problem.

My opinion: Can you consider compressed air? Just skip it for hydrogen, safety comes first? The owner's opinion should be followed. The number of pipes and elbows should not be increased at will. It should be used as a maintenance platform. This standard has not yet been found. * * The standards cannot be so detailed. They can be more flexible without violating the standards (but safety must be considered).

Safety valve adjustment during load test operation 1. Safety valve adjustment should be carried out under the supervision of competent professional and technical personnel. 2. Before adjustment, strength and air tightness tests should be carried out according to regulations. 3. The safety valve should generally be calibrated with nitrogen and sealed before the unit load test operation. 4. The safety valve that needs to be adjusted for the second time during the load test operation of the unit should have: The first adjustment of water pressure has been carried out according to relevant regulations. ； In addition to the intact unloading device of the unit, the manual unloading device of the safety valve must be flexible and reliable. 5. Safety valve adjustment during the load test operation. One is to set the opening pressure of the safety valve basically at the highest working pressure of the level during the first adjustment, so that the final adjustment can be made from low to high during the load test operation. During this process, the compressor must be overloaded. ； The other method is to first use water pressure to adjust the opening pressure of the safety valve to the lowest or rated working pressure of the level. During the load test operation, you should pay attention to whether it takes off at this constant pressure and make appropriate adjustments (the tripping pressure should always be controlled not to be greater than the maximum working pressure of the level during the adjustment process). Based on the changing relationship between the adjustment amount of the safety valve and the tripping pressure, adjust the safety valve to the specified tripping pressure range based on experience, then remove the safety valve and conduct a verification with water pressure.

Personally, I think that as long as it is not denied in the standard, it is feasible. If the law does not clearly stipulate it, it is correct and can be placed below.

1. According to the safety valve installation requirements in Article 152 of the "Capacity Regulations", the safety valve can be installed by piping to a location that is easy to inspect and maintain. 2. In order to avoid violating the safety valve installation requirements in the Capacity Regulations (the pipe connection between the container and the safety valve should be as short and straight as possible), it is recommended that LZ install the safety valve in accordance with Article 141 of the Capacity Regulations, that is, install the safety valve of the storage tank on the air inlet line of the storage tank, but attention is required to ensure its flux area. 3. Excerpt from Article 141 of the Regulations: “. . . When the pressure source comes from outside the pressure vessel and is reliably controlled, the safety relief device (safety valve or bursting disc device) does not need to be installed directly on the pressure vessel. ” 4. This installation method can not only meet the requirements for inspection, maintenance and calibration, but also comply with the relevant provisions of the "Capacity Regulations". This is how the safety valve of our 150M3 nitrogen storage tank is installed. For reference!

I don't think so. First of all, it violates the principle of safety valve installation (mentioned on the 4th and 5th floors). Secondly, you pipe the safety valve to the lower part. There is an extra pipeline between the safety valve and the tank, which stores hydrogen. If the pressure cannot be released in time, it will be very dangerous! So I think it’s best not to change it! I agree with the idea of ​​setting up a maintenance platform upstairs! Maintenance is only once a year, but safety is a daily matter!

The standard does not say that it is forbidden, but it can be connected to the lower part through the gas pipeline, but it must be recalculated and checked, and the designer must ensure the safety of the equipment. If something goes wrong, it's the designer's responsibility. Whoever signs it is responsible.

Compressed air and hydrogen are both permanent gases and do not have a liquid phase, so they should be able to be installed under the tank. The safety valves of cryogenic storage tanks are installed below the storage tank.