In the current compressed air system of pneumatic users in China, the existence of energy waste is mainly caused by large leakage, screw air compressor configuration and operation only for pressure keeping, supply pressure is not reasonable, air gun nozzle is inefficient, equipment gas is wasted. On-site workers have a low awareness of gas costs and so on.
In the case of leakage of screw air compressors, the leakage in the factory usually accounts for 10 to 30% of the gas supply, and the factory with poor management may even be as high as 50%.
Sometimes there are 20,000 leaks in a car assembly shop, of which more than 90% of the leaks come from aging or damage to the parts in use. What is especially serious is that the on-site management staff far underestimated the losses caused by the leak. For example, a 1mm diameter hole caused by a welding slag in a spot welding station of a car can cause up to about 3,525 kWh of electricity per year, which is almost equivalent to the annual household electricity of two family of three. Strengthening the awareness of leakage losses, popularizing leak detection and prevention methods are the current priorities. At present, some domestic enterprises are beginning to use leak detectors and leak detectors to detect leaks and leaks, and have achieved some results.
Reasonable configuration and reasonable operation of the screw air compressor is very important to save electricity. Usually, in order to make the output pressure fluctuation small, many compressors adopt an intake valve adjustment mode. In this way, if there is no air supply, it still needs to consume 70% of the rated power, and the waste is more serious. To this end, the introduction of variable frequency control, the use of compressor group expert control system and other measures to reduce power is very effective. These are largely ignored in the actual operation of the plant, ensuring that pressure is the only requirement for compressor management in most plants. In addition, because the pipeline pressure loss is uncertain, the equipment starts to have a peak flow rate, etc., the supply pressure of the screw air compressor is sometimes 0.2-0.3 MPa higher than the on-site required pressure, and the waste is very serious. Sometimes, for a small number of pressure-demanding equipment, and the entire increase in gas supply pressure, this is extremely unreasonable in the energy use configuration, it is not wise. Various problems indicate that the current gas consumption in the use of compressed air systems is more serious.
96% of the energy consumption of the air compressor system is the power consumption of industrial compressors. This shows that while we adjust the industrial economic structure, we also need to greatly improve the energy efficiency of the compressed air system. By adopting reasonable and effective energy-saving measures, energy-saving effects of 30% or higher can be achieved.
Statistics show that the leakage of compressed air system can generally be as high as 30~50%, about 10~30% of well-managed factories or new plants, and the acceptable range is about 5~10%. Common leak points in compressed air systems are available; Air compressor inside, gas storage tank, dryer, pipeline, valve parts, joints, welding points, gas equipment, etc. The user is more likely to observe the larger leakage points of the compressed air system. Generally, the power consumed by the compressed air system accounts for about 20~30% of the electricity consumption of the enterprise. Among them, the air compressor unit is the main source of power consumption. Therefore, reducing the power consumption of the air compressor is the main key to energy saving of the air compressor system. The rated capacity of the air compressor is the maximum load capacity of the equipment, but the fluctuation of the gas load of the system is usually quite large. According to the usual experience, about 70% of the air compressors operate within the range of 40-80% of the rated capacity. The load fluctuation part is usually adjusted by the empty weight truck, the intake valve tolerance (commonly known as the capacity adjustment machine) or the variable frequency machine. The well is matched with the complete operation plan. When the gas consumption is low, the operation of some air compressors is stopped, and the whole system is allowed. The lower the operating capacity, the better.
At present, the general screw air compressor mostly adopts the empty heavy vehicle control (commonly known as the standard machine). When the exhaust pressure reaches the unloading set value, the truck is turned to the empty vehicle or the load is lower than the loading pressure. Even in the case of empty cars without gas production, there will still be up to about two-thirds of the power consumption ports. Many air compressor users are equipped with a VSD variable frequency air compressor in order to improve the operating efficiency and economic efficiency of the air compressor. (Commonly known as frequency converter), it can operate within 40~80% fluctuation range of system compressed air without exceeding its rated air volume range, which can keep the system exhaust pressure constant and make other standard machines in the system. Run as much as possible in the state of heavy vehicles, reduce the proportion of time spent running, so the savings in electricity costs are considerable.
