Which control method is better?
Thread Content
There are two common methods of control for evaporators under negative pressure (with partial phase change): 1. Controlling the exit temperature of the process fluid from the evaporator by adjusting the steam pressure (steam condensation pressure)； 2. Adjust the outlet temperature of the process medium in the evaporator using the heated steam flow rate ； What are the advantages and disadvantages of each when compared to the other?
Generally, the pressure of the heating steam should be a fixed or stable value; therefore, under normal circumstances, the heating temperature is controlled by the flow rate.
Supported. Normally, it is controlled through a TICV; the outlet temperature of the process material is used to control the opening degree of the steam inlet valve, thereby achieving automatic control
The second method, which uses flow rate to control the outlet temperature on the process side, is a conventional control approach and quite common; however, the first method is also frequently used in foreign processes
How does steam pressure change? And thus affect the material outlet temperature? ? If the control valve is installed on the steam pipeline, then what needs to be adjusted is still the steam flow rate!
The steam pressure measurement point is located after the control valve, and the TIC is adjusted via PIC bypass control
These two control methods are essentially the same; both involve adjusting the steam pressure to control the heating load