To properly use the anti-surge adjustment system, first determine the surge curve of the compressor, and then determine the equation for the anti-surge adjustment curve based on the anti-surge regulation system used and the system variables in the actual operation of the compressor. Take out the anti-surge adjustment curve and adjust the various parameters of the anti-surge adjustment system accordingly. Taking the commissioning and use of the anti-surge regulation system of the VK63 turbopoil air compressor of the 10,000-meter oxygen concentrator introduced by our company as an example, the surge curve and the anti-surge control curve are determined. And commissioning and use of pneumatic anti-surge regulation system. 1. Pneumatic anti-surge regulation system of VK63 turbotype air compressor The load of the turbine air compressor is relatively stable. In addition to the change of the discharge pressure of the compressor and the volume flow flowing through the compressor during operation, the other system variables do not change much, so this anti-surge regulation system A pneumatic anti-surge regulation system for compressor outlet pressure inlet flow is used. The output control signal is compared according to two input signals. The pressure signal P 2 is used as a measured value by the calculator, and the flow signal P is used as a set value. The size of the two input signals varies with the compressor (flow, compression ratio, etc.), and the adjustment system is a follow-up adjustment system. Second, the test and determination of the surge curve of the turbine air compressor In the actual operation of the turbo compressor, due to atmospheric pressure, air temperature, changes in the cooling state of the compressor, etc., the actual running curve of the compressor and the theoretical surge curve of the design state are not exactly the same. In the actual commissioning and use of the adjustment system, the control curve should be determined based on the actual surge curve, in order to make the compressor work in the maximum range and obtain the highest working efficiency. When measuring the surge curve, place the regulator in the manual operation position and maximize its output, so that the release valve is fully open. After the compressor starts running, the inlet vane is first controlled to the opening of 75, and the regulator is operated. Manual knob, slowly close the release valve, gradually increase the pressure at the compressor outlet until a slight surge occurs, then quickly open the release valve, release the surge, and record the flow before and during the surge. And pressure values. In the same way, the flow and pressure values ​​of the inlet vanes are controlled at 45, 30, and 23, before and during surge, and the inlet vanes are controlled at 75, 45, and 30 in the P and P 2 rectangular plots. The working curve at 23 o'clock marks the surge point on each curve and connects the surge point, which is the surge curve when the compressor is actually running. Third, the determination of the control line of the pneumatic anti-surge regulation system The determination of the anti-surge control line should be based on the actual operating conditions of the compressor with a suitable safety margin. According to the design requirements of the oxygen control equipment for the anti-surge control system of the air compressor, the control line should be greater than 8 10% of the surge curve. Fourth, the stability study of anti-surge control system During the operation of the compressor, due to operation and system variables, it often leads to the occurrence of anti-surge adjustment action, which will affect the normal operation of the oxygen generator unit, resulting in unstable working conditions. At this time, first determine whether the unit is operating in the work area. If the adjustment system is adjusted after it is close to the surge zone, it is necessary to change the working state of the compressor. If it is running in the working area and far from the surge zone, the adjustment system is adjusted. It is necessary to check the adjustment system and check whether the various parameters of the adjustment system are reasonable. For example, in January 1998, the adjustment system instantaneously operated during the air separation switch, and the discharge valve of the compressor was opened. After the switching was completed, the discharge valve was closed again, resulting in unstable working conditions. At that time, the discharge pressure of the compressor was 5. 2bar, and the flow meter indicated 53000N 3 /h. When the air separation was switched, the pressure rose to 5. 4bar, and the flow rate dropped to 50500M 3 / h. For this, we will switch the compressor before the air separation. The working point and the operating point when the air separation is switched are compared with the surge control line. It is found that when the air separation is switched, when the discharge pressure of the compressor rises and the flow rate drops, the operating point has exceeded the surge control line. It is therefore necessary to keep the operating point of the compressor below the surge control line by increasing the flow through the compressor or by moving the surge control line up. Which method is more reasonable? If you increase the flow rate, you only need to open the compressor inlet guide vanes, but the flow rate will increase, the load of the compressor will increase, and the power consumption will increase. When the amount of processing air increases, the oxygen production increases, and when the output is greater than the user's usage, the oxygen emission rate increases. In actual operation, the flow rate is affected by temperature as shown by the flow meter. On the suction pipe, the pressure at the orifice plate does not change much in winter and summer, and the temperature difference at the orifice plate reaches 40. At 12 o'clock on July 28, 1997, the temperature at the orifice plate is 35, January 3, 1998. At 12 o'clock, the temperature at the orifice is -5. From the orifice data sheet: T.= 308K, T= 268K. According to the flow correction formula: Q n = TO / TQ 0: Q 0 = 53000M 3 / h, Q n = 56817M / h. Therefore, it is not advisable to increase the amount of processing air. According to the position of the working point of the compressor relative to the surge line, the safety margin of the anti-surge control line is somewhat large, which causes the working area of ​​the compressor to shrink and reduce the working efficiency of the compressor. It is therefore necessary to reduce the distance between the surge line and the control line. According to the requirement that the control line needs to be greater than 10% of the surge line, and the actual operation of the compressor, adjust the value of the calculator setting input C in the adjustment system to 0.3 bar, and move the surge control line upward. The instantaneous venting caused by the air compressor at the time of air separation switching was removed. And after more than two years of actual operation, this anti-surge regulation system has been working very well.
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Analysis on the Detection and Stability of Turbine Control System
The anti-surge adjustment system of any turbo compressor needs to be designed and commissioned according to the comprehensive operating conditions and the determined system variables.