In modern industry, as an important power equipment, air compressor is widely used in various production processes. However, the energy consumption of air compressor has always been the focus of enterprises. With the enhancement of environmental awareness and the rise of energy costs, how to effectively save energy has become a key issue in the use and maintenance of air compressors. This paper will deeply discuss many aspects of energy saving of air compressor, help readers master the key points of energy saving, and realize green and efficient operation of air compressor. Criticism and correction are welcome for inadequacies.
I. treatment of leakage
It is estimated that the average leakage of compressed air in the factory is as high as 20% 30%, while a small hole in 1mm ², under 7bar pressure, leaks about 1.5L/s, resulting in an annual loss of about 4000 yuan (for all pneumatic tools, hoses, fittings, valves, etc.). Therefore, the primary work of energy saving is to control the leakage, to check all the transmission network and gas points, especially joints, valves, etc., to deal with the leakage point in time.
II. Treatment of pressure drop
Every time the compressed air passes through an equipment, the compressed air will be lost, and the pressure of the air source will be reduced. General air compressor outlet to the gas point, the pressure drop can not exceed 1bar, more strictly is not more than 10%, that is, 0.7bar, cold-dry filter section of the pressure drop is generally 0.2bar. The factory should arrange the ring pipe network as far as possible, balance the gas pressure at each point, and do the following:
Through the pipeline section to set up a pressure gauge to detect the pressure, check the pressure drop of each section in detail, and check and maintain the problematic pipe network section in time.
When selecting compressed air equipment and evaluating the pressure demand of gas equipment, it is necessary to comprehensively consider the gas supply pressure and gas supply volume, and should not blindly increase the air supply pressure and total power of the equipment. In the case of ensuring production, the exhaust pressure of the air compressor should be reduced as far as possible. Every reduction of 1bar of the exhaust pressure of the air compressor will save energy by about 7% ~ 10%. In fact, as long as the cylinders of many gas equipment are 3~4bar, a few manipulators need more than 6bar.
Third, adjust the behavior of gas use
According to authoritative data, the energy efficiency of the air compressor is only about 10%, and about 90% of it has been converted into thermal energy loss. Therefore, it is necessary to evaluate the factory pneumatic equipment and whether it can be solved by electric method. At the same time, unreasonable gas use behaviors such as using compressed air to do routine cleaning should be put an end to.
Fourth, adopt centralized control mode
Multiple air compressors are centrally controlled, and the number of running units is controlled automatically according to the change of gas consumption. If the number is small, a frequency conversion air compressor can be used to adjust the pressure; if the number is large, centralized linkage control can be adopted to avoid the rise of stepped exhaust pressure caused by the parameter setting of multiple air compressors, resulting in a waste of output air energy. The specific advantages of centralized control are as follows:
When the gas consumption is reduced to a certain amount, the gas production is reduced by reducing the loading time. If the gas consumption is further reduced, the air compressor with good performance will stop automatically.
Reduce the motor shaft output power: adopt the frequency conversion speed regulation mode to reduce the motor shaft power output. Before the transformation, the air compressor will unload automatically when it reaches the set pressure; after the transformation, the air compressor will not unload, but reduce the rotational speed, reduce the gas production and maintain the minimum pressure of the gas network, thus reducing the power consumption from unloading to loading. At the same time, the operation of the motor is reduced to below the power frequency, which can also reduce the output power of the motor shaft.
Extend the life of the equipment: use the frequency conversion energy-saving device and make use of the soft start function of the frequency converter to make the starting current start from zero and the maximum does not exceed the rated current, so as to reduce the impact of the power grid and the requirements of power supply capacity, and prolong the life of equipment and valves.
Reduce reactive power loss: motor reactive power will increase line loss and equipment heating, resulting in lower power factor and active power, resulting in inefficient use of equipment and serious waste. After using the frequency conversion speed regulation device, due to the function of the internal filter capacitor of the frequency converter, the reactive power loss can be reduced and the active power of the power grid can be increased.
5. Do a good job in equipment maintenance
According to the operation principle of the air compressor, the air compressor absorbs the natural air and forms high-pressure clean air for other equipment after multi-stage treatment and multi-stage compression. In the whole process, the air in nature will be continuously compressed, absorbing most of the heat converted by electric energy, so that the temperature of the compressed air will rise. The continuous high temperature is disadvantageous to the normal operation of the equipment, so it is necessary to cool the equipment continuously. Therefore, it is necessary to do a good job in equipment maintenance and cleaning, increase the heat dissipation effect of the air compressor and the exchange effect of water-cooled and air-cooled heat exchangers, and maintain the oil quality, so as to ensure the energy-saving, stable and safe operation of the air compressor.
VI. Waste heat recovery
Air compressor usually uses asynchronous motor, the power factor is relatively low, mostly between 0.2 and 0.85, which changes greatly with the change of load, and the energy loss is large. The waste heat recovery of the air compressor can reduce the exhaust temperature of the air compressor, prolong the service life of the air compressor, and the service cycle of cooling oil. At the same time, the recovered heat can be used for domestic heat, boiler feed water preheating, process heating, heating and other occasions, with the following advantages:
High recovery efficiency: oil and gas double heat recovery, large temperature difference between inlet and outlet water, high heat recovery efficiency. All the heat of the air compressor oil and gas is recovered, and the cold water is quickly and directly converted into hot water, which is sent to the hot water storage system through the insulation pipe, and then pumped to the hot water point used in the factory.
Space saving: original direct heating structure, small footprint and convenient installation.
Simple structure: low failure rate and low maintenance cost.
Low pressure loss: high efficient compressed air waste heat recovery device is adopted to achieve zero pressure loss of compressed air without changing the flow channel of the air.
Stable work: keep the oil temperature in the best working range to ensure the stable operation of the air compressor.
The motor load rate of the air compressor is kept above 80%, which can improve the energy saving efficiency. Therefore, it is necessary to give priority to the efficient motor and reduce the floating capacity of the motor. For example:
The power consumption efficiency of Y-type guide motor is 0.5% lower than that of ordinary Jo motor, and the average efficiency of YX motor is 10%, which is 3% higher than that of Jo motor.
The use of magnetic materials with low energy consumption and good magnetic conductivity can reduce the consumption of copper, iron and other materials.
The ordinary old-fashioned transmission (V-belt transmission and gear transmission) will lose more transmission efficiency and reduce energy-saving performance. The emergence of motor coaxial and rotor structure can completely solve the energy loss caused by mechanical transmission and increase the air volume. at the same time, it can also control the rotational speed of the equipment in a full range.
In the selection of air compressor, priority can be given to the use of efficient screw air compressor. In view of the production gas consumption of enterprises, it is necessary to consider the use of gas in peak and trough periods and adopt variable working conditions. The high-efficiency screw air compressor is beneficial to energy saving, and its motor saves more than 10% energy than the general motor, and has the advantages of constant pressure air, no waste of pressure difference, how much air is injected with how much air, and no loading and unloading, and more than 30% energy saving than the ordinary air compressor. If the production gas consumption is large, the centrifugal unit can be used, high efficiency and large flow can alleviate the problem of insufficient gas consumption in the peak.
VIII. Transformation of drying system
The traditional drying system has many disadvantages, but the new drying equipment can use the waste heat of air pressure to dry and dewater the compressed air, and the energy saving rate is more than 80%.
In short, equipment, operation management and other factors affect the energy consumption of the air compressor. Only comprehensive analysis, comprehensive consideration, selection of advanced technology, reasonable and feasible methods and supporting measures can ensure the energy-saving, stable and safe operation of the air compressor. While applying advanced technologies and methods such as frequency conversion speed regulation, the staff should also conscientiously do a good job in the daily operation management and maintenance of the equipment, save energy and reduce consumption on the basis of ensuring production, so as to improve economic and social benefits.
Post time: Oct-25-2024
