The degree of influence of the design temperature specified in the process on materials, etc

The above two temperature ranges should have no impact on the material of the equipment. However, when the temperature is too high or too low, such as 420 degrees Celsius or -50 degrees Celsius, it is necessary to consider using appropriate materials.

Thank you! I’m always at a loss when it comes to this question. As you answered, below a certain temperature, it has no effect on the material, but the inspection and management of the equipment manufacturing process may vary. There is the following passage: “Working pressure (also known as operating pressure) refers to the pressure at the top of a vessel during normal process operation.” The maximum operating pressure refers to the highest pressure that may occur during normal process operation. When the pressure exceeds this value, the safety device on the container will activate. The determination of the maximum operating pressure depends on the working medium. Design pressure refers to the pressure at the corresponding design temperature that is used to determine the calculated wall thickness of the vessel and the dimensions of its components. The Regulations on Safety Supervision of Pressure Vessels stipulate that the design pressure of a vessel shall not be lower than the maximum operating pressure. For pressure vessels equipped with safety relief devices, their design pressure shall not be lower than the opening pressure or burst pressure of such relief devices. The operating temperature of a pressure vessel refers to the temperature of the working medium inside the vessel during normal operation, that is, the temperature of the medium. The design temperature refers to the highest or lowest temperature that the shell wall or the metal components of a vessel may reach under the corresponding design pressure during normal operation. When the temperature of the shell wall or component metal is below -20°C, the design temperature is determined based on the lowest temperature; otherwise, the design temperature is always selected based on the highest temperature. The operating temperature of a pressure vessel refers to the temperature of the medium, while the design temperature refers to the design temperature of the shell. ” I don’t know what this “below -20°C” means, or why the monitoring regulations use this temperature as a threshold ” From the perspective of a standardized system, does it explain things better? I work in the manufacturing field, and I’m very confused about this issue. The operating environment for the equipment is above 0°C, but in many cases the conditions imposed on the equipment are -20°C. I hope you can help me! Thank you so much!

This temperature is the threshold for low-temperature containers. If the reading is below -20, a cryogenic container should be considered. Of course, it is also possible to operate under conditions of low temperature and low stress

The design temperature specified in the process documentation is 0–120 degrees Celsius or -20–100 degrees Celsius; the process cannot specify such a wide range of temperatures. For example, it should be 50 degrees exactly, rather than a range from 0 to 50 degrees, as this makes it impossible to determine the allowable stress of the materials used in the container design accurately.

For process designers, when specifying the design conditions for equipment, it is sufficient to mention the operating temperature and pressure, as well as the medium and its properties. Of course, it is best to recommend a suitable material based on practical experience, without specifying the design temperature and pressure. Since the design temperature and design pressure are determined by equipment designers based on the most unfavorable combinations of operating temperature, operating pressure, and other factors, they also serve as the basis for selecting materials for the equipment, determining its thickness, and carrying out manufacturing inspections and acceptance tests. Whether these values are reasonable has a significant impact on the manufacturing and use of the equipment.

No problem, they’re all within the same range.