Reasons for Inefficient Operation of Air Compressor

A large amount of data shows that the main cost of the compressed air system is spent on the operation link, and in its life cycle, the operating cost (electricity) accounts for 78-92%. Therefore, how to tap the potential of energy consumption and improve energy efficiency through fine management is a topic that every enterprise must face. In this regard, according to the project engineering experience, it is found that the main reasons for the high energy consumption of most compressed air systems are as follows:

(1) Low equipment efficiency

many years ago, most of the air compressors configured belonged to low energy efficiency equipment, which was unreasonable to match with terminals and other equipment, only to meet the basic needs of production. The air compressor is backward in regulation mode and has no centralized control. When the air consumption changes randomly, the air compressor is seriously wasted due to unloading. The gas consumption of terminal equipment is unreasonable, the efficiency is low, and the gas consumption of equipment is wasted.

(2) Unreasonable gas supply pressure

there is no hierarchical planning of the gas supply pressure, but a simple use of high-pressure gas supply plus mechanical self-pressure reducing valve to meet different pressure requirements, a lot of energy is wasted on the valve. In addition, when the demand-side gas consumption changes cause random fluctuations in pipe network pressure, in order to avoid frequent start and stop of the unit, it is necessary to set a wide range of pressure changes, resulting in large fluctuations in the outlet pressure of the air compressor, increasing the operating energy consumption of the air pressure system.

(3) Causes of energy waste

a. High no-load energy consumption

at present, most enterprise compressors are single N cubic meters, and the start and stop of compressors are only N or multiples of N. The start and stop of air compressor equipment depends on manual management. Especially when the gas load changes frequently, the system can not react quickly and can not realize the fine adjustment of the compressor displacement, which forms the no-load of each compressor in the air compression station.

Under normal circumstances, when the pressure reaches y kg, the air compressor enters the unloading operation state. When the pressure drops to x kg, the compressor enters the no-load state, that is, the intake valve is closed to make the motor in the idling state, and the oil and gas pre-separation The excess compressed air in the tank is vented through the vent valve. Close the intake valve to make the motor idling. Although the air compressor does not need to compress the gas for work, the air compressor still needs to drive the screw or piston to rotate during idling, and the power consumption continues to occur. The actual test found that the energy consumption of the air compressor at no load is as high as 40% to 55% of its full load operation.

B. High climbing energy consumption

the screw compressor has two operation modes: loading and unloading operation mode or no-load and full-load operation mode. The loading and unloading control mode makes the pressure of compressed gas move back and forth between x kg ~ y kg. X kg is the minimum working pressure value, that is, the minimum pressure (loading pressure) that can ensure the normal work of the user. In general, the relationship between x kg and y kg can be expressed by the formula: y kg = x kg +(1 + & delta;),& delta; is a percentage, and its value is roughly between 10% and 25%. The pressure difference is generally more than one kilogram. Through theoretical calculation and practical detection, it is known that the energy consumption increases by 5-6% for every 1kg of air compressor pressure.

It can be seen that in the air compressor under the control mode of adding and unloading air supply, its working air pressure is from x to y, there is an energy consumption of air pressure climbing, and there is a waste of energy in fact. At the same time, more than x kilograms of gas before entering the gas terminal, the pressure needs to be reduced to close to x kilograms through the pressure reducing valve. The higher the pressure, the faster the flow rate, which results in the same working condition. The higher the pressure, the greater the gas consumption. This process is also a waste of energy.

c. Traditional management

there are two inevitable contradictions in the use and management of air compression stations. One is that the enterprise has a clear assessment of the management personnel of the air compressor, so there will be a habit that the air pressure is often not enough or can be opened less, which is not conducive to the normal operation of the production line, or the failure of the air terminal due to the pressure not meeting the equipment use requirements will increase. One is that there is no clear assessment of air compressor managers, which will lead to more air compressors and high no-load energy consumption of air compressor stations. No matter what kind of management mode, the result will be an increase in the waste of electric energy in the air compressor station, and it is not conducive to safe production.