Key factors for energy saving of screw air compressor
The rotor profile of the screw air compressor has a certain impact on energy saving. Before 2000, the screw air compressor was still in the growth period, and reliability was the main problem. At that time, the rotor profile development of screw air compressors made reliability the main goal.
After the 21st century, the energy crisis has enveloped the world. The development of the rotor profile of screw air compressors takes energy-saving air compressors as an important goal on the basis of reliability. The SKK line is one of the excellent energy-saving lines produced in this environment. The SKK type line adopts a curved surface-to-curved inner seal. Under the same gap, the sealing effect between the male and female rotors is far superior to the traditional type line with line sealing.
Head manufacturing
The gap between the Yin-Yang rotor and the rotor and the cylinder and cylinder head has a significant impact on the energy consumption of the screw air compressor. Improving the machining accuracy and surface finish of the rotor is an effective means to reduce the gap between the elements of the machine head. The SKK line uses grinding as a means of realization. Therefore, it must be processed with a curved surface grinder. The curved grinding machine with real-time detection and automatic compensation of grinding wheels produced by British Precision Machinery Co., Ltd. has improved the rotor machining accuracy to an unprecedented level.
The grinding machine provided by British Precision Machinery Co., Ltd. for SKK line processing is a new generation of machine tools after 2006. The processing capacity has been increased to 370mm diameter, the processing accuracy has reached 2 microns, and the finish has reached 10 levels. Prior to this, the rotor of such a large screw air compressor was processed by a milling machine, with a processing accuracy of 40 microns and a smoothness of up to level 6. Screw machine configuration Male rotor speed is the main parameter to measure energy saving, life and reliability of screw air compressor. The power loss of the belt drive is 5%, and the power loss of the gear transmission is 3%. The prerequisite for energy saving of the screw air compressor must be that the speed of the male rotor is equal to the speed of the main shaft of the motor. Under the electric system of 50 Hz, the speed of the male rotor is equal to 1485 rpm or equal to 2985 Rpm. The life of the screw air compressor is strictly inversely proportional to the rotation speed of the male rotor. Use efficiency The screw air compressor consumes 30% to 40% of the rated motor power when idling, and the efficiency of the screw air compressor drops by about 5% during some operating conditions. All screw air compressors are designed for a specific working condition. When operating under the design conditions, the screw air compressors are more energy-efficient. When the air output of the screw air compressor continues to be equal to the air consumption of the pipe network, the screw air compressor is in a state of energy saving. Energy-saving analysis of inverter air compressor 1. The frequency converter itself consumes 3% of the power. When the motor deviates from the rated power and the rated speed, the efficiency drops significantly. When the screw air compressor speed deviates from the rated speed, the mixing ratio of good oil and gas is destroyed, and the efficiency also drops significantly. Therefore, the use of variable frequency screw air compressors, although making the gas production continuously equal to the air consumption of the pipe network, but the power used to produce each cubic compressed air has increased. That is to say, under continuous loading conditions, variable frequency screw air compressors do not save energy. 2. In most screw air compressor use cases, the air consumption of the pipe network is constantly changing, and the air production of the air compressor cannot be equal to the gas consumption of the pipe network. When the pressure of the pipe network is equal to the set value, the screw air compressor enters the no-load state The screw air compressor consumes 30% to 40% of the rated power of the motor when idling, so the screw air compressor has very low efficiency when idling. Reducing the idling time or preventing the screw air compressor from entering the idling state has a certain energy saving effect. 3. The variable frequency screw air compressor can effectively reduce the idle time or prevent the screw air compressor from entering the idle state, so when the rated air production of the air compressor is greater than the air consumption of the pipe network, the variable frequency screw air compressor has a certain energy saving effect 4. The variable frequency screw air compressor is very effective for stabilizing the pressure of the pipe network, which can stabilize the pressure of the pipe network within the range of ±0.01MPa-this is difficult to achieve by other flow control methods. Air compressor station configuration The principles of energy-saving air compressor station configuration are: 1. The gas production continues to be equal to the gas consumption of the pipe network; 2. A single air compressor is either in rated working condition or in shutdown state. According to the statistical analysis results, the air consumption of the pipe network is distributed to multiple air compressors, and a larger air compressor is used to provide a constant part of the gas consumption; several smaller air compressors are put into operation or stopped according to the change in gas consumption. A frequency conversion air compressor further fine-tunes the air supply. The waste heat of the screw air compressor has great use value, and the energy-saving air compressor station should fully consider the recovery and utilization of waste heat.
