Regarding the relationship between design pressure and the setting pressure of rupture discs

Should there not be a safety valve behind the burst disc? Check what the setting pressure of that safety valve is. Generally, the setting value of the burst disc should be the same as the operating pressure of the safety valve located downstream; and the operating pressure of the safety valve is usually the design pressure of the equipment it is meant to protect. Therefore, the setting pressure of the burst disc should correspond to the design pressure of the reactor. Is it a new plant built by Yangzi or Huajin? Also, as far as I know, there shouldn’t be safety valves or burst discs on EO reactors

It has only a burst disc, no safety valve; this device is a design from 1992, with all design elements and equipment coming from abroad

The set pressure of safety devices such as rupture disks or safety valves should not be higher than the design pressure of the equipment; otherwise, they will fail to provide protection for the equipment. The test pressure for the water pressure strength of equipment is generally 1.5 times the design pressure of the equipment. According to the original poster, the hydrostatic test pressure of 4.1 MPa is exactly 1.5 times the set pressure of the rupture disc, which is 2.76 MPa. Therefore, the design pressure for the reactor should be 2.76 MPa, rather than 2.34 MPa; otherwise, there will be problems.

The reaction between ethylene and oxygen to produce EO is a very dangerous one. I would like to know the specific details from the second floor – whether the ethylene route is being used; otherwise, blast discs should be in place

I just checked the PID for SD’s other projects, and indeed, there are rupture disks on the reactors with venting in place to ensure safety. The SD from 92 – is it from Xinjiang or Anhui? I didn’t make it clear just now; the safety valve I was referring to is located on the inlet pipeline of the reactor, not on the reactor itself. It is also the ethylene route

I have a question: I’m not sure if it’s correct, but whether the concept of design pressure abroad is exactly the same as that in China. There’s also the concept of MAWP – I’m not sure how to explain and define it specifically

Now, large projects all use foreign standards. Generally, the design pressure in domestic countries is more conservative compared to that in foreign countries. The MAWP, or maximum working pressure, is equivalent to the design pressure

For multi-story buildings, the set pressure of the burst disc = the opening pressure of the safety valve ≤ the design pressure of the equipment.

There is another question: since it is a design from abroad, is the concept of design pressure different in foreign countries compared to that in China? In foreign countries, there is a concept of maximum allowable pressure, namely MAWP – does this correspond to the concept of design pressure used in China?

The design pressure of the container is determined based on the process requirements. The actual ultimate pressure of a container is often several times the design pressure! Of course, depending on factors such as materials and price, the exact amount by which it will be increased will vary. The rupture disc is not designed to ensure the integrity of the process, but rather that of the container; it serves as the final barrier in case the container ruptures. Of course, it is specified based on the container’s maximum allowable pressure. The required design pressure is 2.34 MPa, while the hydrostatic test pressure is 4.1 MPa, indicating a large strength reserve; it is a container with a clearly safety-oriented configuration. Therefore, it is normal for the design pressure of the rupture disc to be higher than that of the container.

I’m still a bit confused by the answer on floor 11; I might not have explained everything clearly. The operating temperature of this reactor is over 200 degrees. The test pressure for the water pressure in the reactor is at 18°C; should the design pressure correspond to the normal operating temperature or to the pressure under the most severe operating conditions that may occur?

The set pressure of the safety accessories on a device or container is determined based on the design pressure of that device or container; this set pressure remains unchanged. The hydrostatic test, on the other hand, is applied to new devices, taking into account a corrosion allowance – in the form of an increased wall thickness – to extend their service life. In my opinion, there is no connection between the set pressure and the hydrostatic test pressure. The set pressure is 1.05–1.1 times the maximum operating pressure, but it must not exceed the design pressure value.

I still don’t understand it. If it’s just a typo, then the heat exchanger before entering the reactor wouldn’t be designed in that way. The design for burst disks and safety valves is completely different: the set pressure for safety valves equals the design pressure, while that for burst disks is much higher. I’ve looked up relevant information; perhaps the AMSE standards can provide some guidance in this regard. I wonder if anyone can give a more reasonable answer

I’ve been reading the company’s regulations lately; unfortunately they’re all in English, so I only understand part of it... It seems that the pressure of the burst disc can be higher than the designed pressure... I’ll go to the company again tomorrow to take a closer look!

The \"Regulations on Safety Inspection of Pressure Vessels\" stipulate as follows: Article 146 – When only one safety valve is installed on a fixed pressure vessel, the opening pressure Pz of that safety valve shall not be greater than the design pressure P of the pressure vessel, and the sealing test pressure Pt of the safety valve shall be greater than the highest operating pressure Pw of the pressure vessel; that is, Pz ≤ P and Pt > Pw. When multiple safety valves are installed on a fixed pressure vessel, the opening pressure of one of these safety valves shall not exceed the design pressure of the vessel, while the opening pressures of the remaining safety valves may be increased appropriately, but must not exceed 1.05 times the design pressure. Article 147: The opening pressure of the safety valve on mobile pressure vessels shall be 1.05 to 1.10 times the design pressure of the vessel; the rated discharge pressure of the safety valve shall not exceed 1.2 times the design pressure of the vessel, and the reseating pressure shall not be less than 0.8 times the opening pressure. Article 148: When a rupture disc device is installed on a fixed-pressure vessel, the designed rupture pressure PB of the rupture disc shall not be greater than the designed pressure of the vessel, and the minimum designed rupture pressure of the rupture disc shall not be less than 1.05 times the highest operating pressure PW of the vessel; that is: PB ≤ P, and PBmin ≥ 1.05Pw

It is estimated that 2.34 MPa should be the maximum pressure that can be reached during normal operation; this is likely not the design pressure of the equipment as mentioned by LZ. Moreover, based on these parameters, a reverse-arch shaped rupture disc should be selected