Pressure setting issue of the safety valve in atmospheric pressure towers

For this, you need to refer to the relevant regulations in GB150. For containers that we manufacture, the setting pressure of the safety valves is generally 1.1 times the maximum operating pressure. You can take a look at this link: http://bbs.hcbbs.com/thread-189767-1-1.html. This post was last edited by gbg9773 on 2008-5-1 at 12:11

I have read your information! 1 Scope of Application 1.0.1 These regulations apply only to the installation and calculation of safety valves designed to prevent overpressure in pressure vessels within chemical production facilities where the pressure is greater than 0.2 MPa; they do not cover ultra-high pressure systems with pressures exceeding 100 MPa. Suitable for safety valves used in pressure vessels and pipelines within the aforementioned range in chemical production facilities; not suitable for safety valves used in pressure vessels in other industries, such as various tank trucks, various gas cylinders, boiler systems, containers made of non-metallic materials, as well as the nuclear industry and power industry. 1.0.2 The calculation methods are derived from the \"Regulations on Safety Inspection of Pressure Vessels\" and API-520 (see Section 2.3); when applying these regulations, the same standards shall be used for calculating the discharge volume and discharge area. The pressure gauge on this tower I’m talking about cannot detect any significant pressure under normal operation – it shows ambient pressure; in winter, there is even a slight negative pressure. It cannot reach 0.2 MPa. What do people say should be the maximum operating pressure? What should those specializing in equipment do then? This post was last edited by zhaojh on 2008-5-1 13:49]

For equipment operating at atmospheric pressure, as long as it can remain connected to the atmosphere under normal operating conditions and there is no pressure buildup, safety valves are not required in principle； But sometimes, for various reasons, special situations may arise (such as the need for purging/relieving pressure), and safety valves are installed to ensure the safety of the equipment ； At this point, determining the setting pressure for the safety valve requires taking into account various factors, such as the maximum pressure that may occur and the strength of the equipment under normal conditions (the allowable maximum pressure). Of course, the setting pressure of the safety valve should be higher than the maximum operating pressure (or the maximum pressure during purging/replacement) and lower than the maximum pressure permitted by the strength of the equipment under normal conditions (the design pressure). This principle must not be violated! :D

PM=0.18+0.1 gauge pressure

Our atmospheric pressure tower is set at 0.3 MPa; around 0.25 MPa should be fine. The key lies in your subsequent equipment as well as the control of operating pressure in the plant

I’m not sure if pressure reactors at normal pressure also need safety valves. A friend said that they aren’t necessary – what are everyone’s opinions?

1) Whether to install safety valves is specified in the “Code for Fire Protection Design of Petrochemical Enterprises” GB50160-92 (1999 edition). (Safety valves should be installed in distillation towers, evaporation towers, and stripping towers whose operating pressure at the top is greater than 0.03 Mpa.) 2) As for the setting pressure of the safety valves, it is generally determined according to the following principles: (P represents the maximum operating pressure of the equipment, and PS represents the setting pressure of the safety valve; both values are gauge pressures.) a) When P is less than or equal to 1.8 MPa, PS = P + 0.18 + 0.1. b) When P is greater than 1.8 MPa but less than or equal to 4.0 MPa, PS = 1.1(P + 0.1). c) When P is greater than 4.0 MPa but less than or equal to 8.0 MPa, PS = P + 0.4 + 0.1. d) When P is greater than 8.0 MPa, PS = 1.05P + 0.1. The setting pressure of the safety valve determined according to these principles must be equal to or slightly less than the design pressure of the equipment.

1. In our company, atmospheric distillation units generally do not have safety valves; if one is needed, it depends on the nature of the material being processed – if there is a risk of clogging the tower due to agglomeration, then a safety valve with a pressure setting not exceeding the design pressure of the equipment can be installed on the reactor. Also, if the material poses a danger, it’s better to direct the waste stream to a tank before releasing it into the atmosphere, as this is safer. I’m not sure if this answer is helpful to you! 2. I have an opinion, though it may not be correct: The process engineering field has to put a lot of thought into different types of equipment and operating conditions, as well as various other factors related to the equipment itself; it’s not easy to come up with reasonable solutions that are well-founded. In contrast, fields related to equipment design rely on process conditions along with strength calculations, which makes the design process more straightforward. The department I work in is small, with not many specialized areas; the engineering department is responsible for doing many tasks and creating various installations, and it’s necessary to have some knowledge of other specialties as well – it’s really exhausting. 3. The set pressure of a single safety valve is equal to the design pressure of the equipment. In the case of multiple safety valves installed for the same designation, the set pressure of the first safety valve to activate is equal to the design pressure, while the set pressures of the other valves are 105% of the design pressure. If the set pressure of LZ’s safety valve is set at 2.0 atm(G), it may cause frequent tripping. 3.0 atm(G); if this value is greater than the device’s designed pressure, it is not allowed. 4. The constant pressure for the tower is generally not more than the design pressure of the equipment