1. If there is no understanding of the structural performance of different types of air compressors, it will cause unreasonable air compressor selection and directly affect the subsequent economic operation of the air compressor.
In general, the power consumption of multi-axis centrifuge, axial flow machine, ordinary single axis centrifuge, screw machine, plug air compressor and other electrical unit consumption increases in turn. For the air compressor with the pressure of 1200nm3/min or more, it is better to select axial air compressor or multi-axis centrifugal unit in the biological fermentation industry, and the air pressure (absolute pressure) required is between 0.30mpa and 0.40MPa. The operation economy and maintenance cost are low; For the axial compressor with adjustable static blade, its advantages are that the adjustable range of working condition is wide, and the best operation area is a curved surface. The unit can ensure that the unit is always in the best economic operation point under different loads. For instrument air with small air demand, the air pressure (absolute pressure) is generally between 0.5-0.8mpa. Screw air compressor is usually selected instead of piston type air compressor. Because screw air compressor has advantages of compact structure, less vulnerable parts, stable operation and good economy.
2. The unreasonable selection of air compressor parameters causes the air compressor to run at the best working condition and the economy of the unit operation is reduced.
For centrifugal air compressor, the pressure and flow rate marked on the nameplate are the working point with the highest efficiency of the air compressor. The operation of the air compressor is not economical when it deviates from the working point. In practice, due to the inaccurate control of the pressure at the air demand point, coupled with the air transport resistance estimation from the air compressor outlet to the user, for safety reasons, the air compressor bidding documents are often drafted, the exhaust pressure and exhaust volume of the air compressor are estimated too high, which results in the deviation of the actual operation data from the design value of the unit. For example, the rated exhaust pressure (absolute pressure) of the air compressor ordered by an enterprise is 0.4MPa, while in actual operation, the exhaust pressure of the air compressor is only about 0.31mpa, and the power consumption of the unit is relatively high. Therefore, when determining the technical parameters of the new air compressor, it is necessary to find out the pressure and air flow resistance calculation of the air use point, and ensure that the design parameters of the air compressor are in line with the actual operation. Only the air compressor selected in this way can play its operation efficiency.
3. The public conditions of air compressor design are harsh, which affect the safety and economic operation of air compressor. If an enterprise purchased a foreign air compressor with a flow of 855m3/min years ago, the exhaust pressure (absolute pressure) of the unit is 0.33mpa. In the public conditions of the air compressor design, the temperature of cooling water of interclass cooler is required to be 5 ℃. In actual operation, the temperature of cooling water is often higher than this temperature, then the secondary air inlet temperature of air compressor is high and the efficiency of the unit is decreased. When using 5 ℃ water, the air compressor has a high air supply cost due to the high cost of 5 ℃ cold water, which makes the air compressor unable to run for a long time. To ensure the economy of air compressor system operation, the public system data corresponding to the site shall be provided as the user in the design of air compressor.
4. The unreasonable design and installation of air compressor after treatment device and the increase of air resistance result in the increase of air compressor exhaust pressure and power consumption.
Some users purchase the air compressor body and the after treatment device separately. If the design capacity of the after treatment device manufacturer is insufficient, only considering the cooling effect and production cost of the air, the number of heat exchange tube fins will be increased in the limited container space, resulting in the air flow obstruction. At the same time, from the outlet of the air compressor to the air main pipe, the increase of the number of elbows will increase the air flow resistance, and reducing the number of elbows can reduce the air resistance; In addition, for the large flow air compressor after treatment device, if the site space allows, two sets of devices can be used in parallel operation, which can effectively reduce the air flow resistance. The author suggests that the air compressor aftertreatment device and pipeline connection should be designed and provided by the air compressor manufacturer to ensure the subsequent operation of the air compressor system is economic and stable.