Selection of screw air compressors
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We are preparing to install a new set of air compression stations. When selecting equipment, energy efficiency and stability are the key considerations. Currently, the two most popular technologies are permanent magnet variable frequency technology and two-stage compression technology. I have used devices based on both of these technologies, and it seems that they are comparable in terms of performance, with each having its own advantages. I’m not sure how to make a choice – what are your opinions?
It is necessary to clarify the design parameters of your air compression station, such as pressure, flow rate, temperature, humidity, as well as the oil and dust content in the air, and to determine their intended use. . . . . . Whether it is used continuously or intermittently, as well as the duration of the intermittent use periods – the more detailed this information is, the better it is for refining the discussion. Another suggestion is to follow the proven practices of similar companies; it’s best to avoid creating new approaches, so as not to be deceived.
The operating conditions are as follows: Rated pressure: 0.8 MPa; Rated exhaust volume: 20 m3/min; Outlet temperature ≤ 40°C; Oil content in the exhaust gas ≤ 3 ppm; Continuous operation. It is known that manufacturers are currently using both of these technologies. The main issues associated with them are as follows: 1. The permanent magnet technology requires high standards for motors, and there are concerns that high temperatures may cause demagnetization over time； 2. Two-stage compression places high demands on the compressor head, involves many vulnerable components, and results in high maintenance costs over time.
Both of these solutions can be used with confidence, as they represent mature technologies. For the latter, the key issue depends primarily on the quality of the air.
Starting with permanent-magnet variable-frequency drives, their advantages include energy savings and high efficiency; they also produce low noise and are easy to maintain. However, they cannot handle very large volumes of flow – for a flow rate of 20 m3/min, it is recommended to use two such drives in operation； Two-stage compression places high demands on the compressor head, and the maintenance costs are relatively high; once there are problems with the head, it generally has to be replaced. The issue between the stages is currently a challenge. This model of compressor has a higher volume of exhaust gas compared to those with single screws of the same type.