What are the advantages and disadvantages of using outlet flow or outlet pressure to control the anti-surge valve in air compressors? What are the chain values respectively?
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What are the advantages and disadvantages of using outlet flow or outlet pressure to control the anti-surge valve in air compressors? What are the chain values respectively? I hope everyone can discuss whether the pressure linkage needs to be more stable
I encountered a problem of this kind today as well; the surge control system based on instruments is completely incomprehensible to me
The main cause of surge is a decrease in inlet flow; therefore, if monitoring is to be carried out, the inlet flow should also be monitored. Our anti-surge valve performs constant-pressure control based on the outlet pressure, while ensuring that the flow rate remains above the anti-surge level. Different devices have different anti-surge capacities; with the anti-surge valve fully closed, it is necessary to ensure that the flow rate remains above the anti-surge capacity.
Surge generally refers to a situation where the compressor’s flow rate decreases to a certain level, or where the pressure rises too rapidly and the guide vanes cannot keep up. Surge prevention valves are usually controlled using two parameters; during compressor startup or normal operation, there are specific surge prevention settings as well as a certain pressure ratio. It is important to be careful not to close the guide vanes too quickly
The air compressor anti-surge control system relies on the combined effects of inlet flow rate (or outlet flow rate), inlet temperature, and outlet pressure. Any change in one of these parameters will cause the operating point to change. There is no specific interlock value; generally, manufacturers provide anti-surge curves and surge curves. As long as the operating point remains on the right side of the anti-surge line, the unit is safe. When the operating point is on the anti-surge line, the anti-surge valve will open slowly and automatically until the operating point moves to the right of the anti-surge line ； When the operating point moves to the left and crosses the anti-surge line, the anti-surge valve will quickly open fully automatically.
There is generally a 10% distance from the anti-surge line to the surge line; the operating point must not cross the surge line. Therefore, by the time the anti-surge line is reached, the anti-surge valve has already opened.
The axial flow fan in my system is controlled based on inlet flow rate, temperature, pressure, and outlet pressure, while the compressor is regulated using inlet flow rate, temperature, pressure, and outlet pressure; the difference is that the inlet side of the axial flow fan is at atmospheric pressure
There are options for both import and export; it depends on how the manufacturer sets it up
Generally, pressure and flow are used in interlocking venting to prevent surging; the pressure is around 5.3 bar, and it depends on the manufacturer’s design as for pressure and flow values
The anti-shock protection here is similar to that on the 5th floor, and its control is also based on outlet flow rate and pressure. .
The anti-surge valve has two mechanisms: pressure control and flow control. When there are deviations from the process parameters and standards, the party with the greater deviation receives higher priority in selection; therefore, flow control and pressure control cannot be simply compared separately. There are also considerations related to the control of anti-surge valves and other factors that affect priority selection