An air compressor is a device that uses an electric motor to compress a gas in a compression chamber and to have a certain pressure on the compressed gas. It is responsible for supplying air to all pneumatic components and various pneumatic valves in the factory in various industries. The biggest energy consumption of air compressors is the consumption of electricity, which accounts for 77% of total consumption, followed by maintenance costs, which account for 18% of total consumption, while equipment investment accounts for only 5% of total cost. The power consumption of the air compressor is very amazing. An air compressor, ranging from tens of thousands of yuan to millions of dollars, but the cost of purchase is only 5%, showing that the power consumption figures are huge. Therefore, the reason for finding the energy consumption of the air compressor can be solved in a targeted manner to improve energy efficiency.
The main aspects of air compressor energy consumption:
1. Control method:
Since the air compressor does not rule out the possibility of long-term operation under full load conditions, the motor capacity can only be determined according to the maximum demand during the selection, resulting in a large margin of the air compressor system. The traditional air compressors adopt the star-delta step-down start, but the current can still reach 2 to 3 times of the rated current when the power frequency starts, and the impact is large, which will affect the stability of the power grid. Most of the air compressors are continuously operated. Because the motor of the general air compressor can not achieve the speed reduction according to the change of the pressure demand, the output power of the motor is matched with the actual pressure demand on the site, resulting in still less air consumption. To run at no load, causing huge waste of electricity. According to statistics, air compressors account for almost 15% of the power consumption of large industrial equipment (fans, pumps, boilers, etc.). The problem of adding and unloading the gas supply control mode is known. The energy consumption analysis knows that the pressure of the compressed gas changes back and forth between Pmin and Pmax. Pmin is the lowest pressure value, which is the lowest pressure that can guarantee the normal operation of the user. In general, the relationship between Pmin and Pmax can be expressed by the following equation: CPmax = (1 + δ) Pmin is a percentage, and its value is roughly between 10% and 25%. If the frequency of the gas supply can be continuously adjusted by the variable frequency speed regulation technology, the pipe network pressure can be maintained at the same time as the supply pressure, that is, near Pmin. It can be seen that the energy wasted in the air compressor under the air supply and unloading control mode is mainly in two parts:
(1) Energy consumed by compressed air pressure exceeding Pmin After the pressure reaches Pmin, the original control mode determines that the pressure will continue to rise (up to Pmax). This process is also an energy consuming process.
(2) Unreasonable adjustment method during unloading The energy normally consumed, when the pressure reaches Pmax, the air compressor is depressurized and unloaded by the following method: closing the intake valve to make the motor idle, and at the same time, the excess in the separation tank The compressed air is vented through the vent valve. This method of adjustment requires a lot of energy waste.
Air compressors have a lot of energy saving, these points must be mastered!
2. Gas leakage:
Only 10% of the energy consumed by the air compressor is converted into compressed air, and the remaining 90% is converted into heat. It can be seen that compressed air is ten times more expensive than electricity, but we often ignore this. In most factories, the sound of air leaks can be heard everywhere, but there is no one to pay attention to. This kind of leakage not only increases the noise, but also the energy waste caused by the leakage, resulting in lower air volume and higher cost. A big eye, a big wind. Because of the leakage, especially the pipeline leakage, if the leakage problem is solved, a lot of energy is saved.