Steam control valve
Thread Content
There is a heat exchanger that uses steam for heat exchange; the steam is regulated by a steam control valve before entering the heat exchanger, and there is a drain trap behind the heat exchanger. The pressure before the control valve is 0.3 MPa of steam. What should the pressure behind the valve be?
The operating pressure is controlled to be slightly lower in accordance with the design of the heat exchanger.
This post was last edited by DXJ122 on 2010-7-26 at 13:32. First, it’s necessary to know the pressure behind the trap; in simple terms, is the drainage done on-site? Should I go into the pressure pipeline network? Additionally, the pressure drop of the control valve is specified during the design phase; for example, it might be set at 0.02 MPa. This is because process requirements must specify the pressure drop in order for them to be able to calculate and select the appropriate valve. Let me make an assumption: if the pressure in the condensate pipeline network is 0.27, and the resistance in the heat exchanger and related pipelines is 0.01, then the pressure behind the valve will be 0.28, while the pressure before the valve is 0.3 as you mentioned. If the condensate pressure isn’t 0.27, or if the resistance in the heat exchanger and related pipelines isn’t 0.01, then we need to start over. . . Simply put, the pressure before the valve is pushed backward from behind. For example, if the condensate is discharged on-site without pressure, the 0.3 value set in front of the heat exchanger cannot be maintained.
Generally, it is advisable to set the pressure drop across the control valve at 1/3 of the total pressure drop in the entire piping system, so as to achieve an effective regulating effect. It is recommended that you determine the pressure drop across the control valve by considering the pressure drops in subsequent sections, including those in the pipelines, heat exchangers, and steam traps. Of course, this is rarely done in general situations; it is only calculated when determining whether a control valve is suitable for use.