Application of FGI FD500 series frequency inverter in air compressor in chemical industry
1.Introduction
In industrial production, the use of compressed gas is very common. In the factory, several air compressors are installed in one place to form an air compressor station. Sichuan Zigong Honghe Chemical Industry Co., Ltd. has a hydrogen press station, installed with three 110kW explosion-proof reciprocating piston hydrogen compressors, used to compress hydrogen. In the design and selection of hydrogen compressor motor capacity, too much consideration of the difference in long-term process requirements before and after construction, so that the margin is too large. In addition, it is difficult to make accurate calculations in the design process, considering the various problems that may occur in the long-term operation process, usually the hydrogen compressor is run for a long time at full load as the basis for selection, but the series of hydrogen compression motors is limited, often can not choose the right motor model, up to 20%~30% is more common. Due to the above reasons, the actual production of hydrogen compressor light load travel time will be significantly increased.
If the frequency conversion speed regulation is used, the speed of the motor is adjusted according to the needs, so that the running power of the motor is reduced in the high efficiency state, and the purpose of energy saving can be achieved under the condition of meeting the production process requirements. From the point of view of operating quality, most hydrogen compressor systems can not be continuously adjusted according to the weight of the load. After the use of frequency conversion speed regulation, it can be very convenient and effective continuous adjustment, maintain the stability of pressure, flow and other parameters, thus greatly improving the efficiency and performance of the compressor.
2.Variable frequency constant pressure gas supply
The frequency inverter and pressure transmitter form a pressure closed-loop system, which automatically reduces the speed of the hydrogen compressor and adjusts the gas supply pressure according to demand, so as to achieve the economic operation of the compressor. Consider installing a pressure transmitter on the gas storage tank to feedback the pressure signal to the terminal of the frequency inverter to form a constant pressure gas supply system, and the gas supply pressure is set to 0.8MPa.
The rated current of the hydrogen compressor motor should be equal to or less than the rated current of the constant torque frequency converter. The frequency converter should have a built-in PID regulator and 4 ~ 20mA analog signal interface. In this example, a FGI FD500 series frequency inverter is selected, and the pressure variable gas supply is selected as Senas DG13W=BZ-A, 1.6MPa.
3.The effect after using FGI FD500 series frequency inverter
After three months of operation, the compressor achieved the expected purpose. No matter how the production process changes, no matter how the gas supply changes, the hydrogen pressure of constant pressure gas supply is maintained at about 0.8MPa, and the gas supply quality is greatly improved.
After variable frequency speed regulation, the air compressor starts smoothly at zero speed to improve production safety. The hydrogen compressor is no longer running at full speed at any time, and the working environment noise is also reduced after the speed is reduced. After the speed is reduced, the mechanical wear is reduced, which is conducive to increasing the life of the compressor and reducing maintenance costs.
In terms of energy saving, it can be seen from the compressor formula that the shaft power PZ(kW) consumed by the compressor is directly proportional to the shaft speed n(r/min), and the compressor displacement QD(m3/min) is directly proportional to the shaft speed, then the shaft power PZ(kW) consumed by the compressor is directly proportional to the compressor displacement QD(m3/min). The shaft power can be saved by reducing the speed. The measured power saving rate reaches 26%, and good economic benefits are obtained.
