Selection of steam pressure relief valves
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The pressure in the steam main is 0.6 MPa; the process only requires a steam pressure of 0.4 MPa, so it should be possible to do without a pressure reducing valve. However, the design pressure of the jacket for the enamel kettle is only 0.6 MPa, with an allowable operating pressure of 0.54 MPa. From a safety perspective, there are concerns that operating the enamel kettle at 0.6 MPa continuously could pose safety risks. When reducing the pressure from 0.6 MPa to 0.4 MPa, the pressure difference is too small; how should a pressure relief valve be selected? I would appreciate your opinions on this.
Reducing it from 0.6 to 0.4 is normal, right? It’s not very small. Tell the control valve manufacturer the parameters, simply.
Are you saying that a pressure relief valve isn’t needed, and only a control valve is sufficient?
Be sure to buy a brand-name one. Otherwise, some will go and do it
There are several approaches: 1: Chain control, where the pressure at the backend is used to control the opening of valves at the frontend. It becomes relatively large, so it is not recommended. 2: Select the pressure reducing valve based on the requirements of the existing operating conditions (medium, pressure, and flow rate). You can consult the relevant manufacturer for this. 3: Install a safety valve or pressure relief valve on the backend to protect the devices there; the pressure of this valve should be slightly higher than that of the backend pressure, for example, 0.55 kilograms. For this approach, gas recovery or direct venting can be considered, depending on the actual inputs and outputs on site. The above are based on personal experience; we can discuss them together to learn from each other.
In some enterprises, pressure control is not achieved using pressure relief valves; it is sufficient to install an automatic pneumatic valve on the steam branch, along with a pressure gauge. The opening degree of the valve can be linked to the steam pressure. However, care must be taken when using this setup – the steam valve should be opened at the appropriate time
This control method works well, providing stable pressure, but it has certain drawbacks: if a device that uses steam stops using steam suddenly, the valves respond slowly, which can lead to excessive pressure