Air Compressor Power Saving Reform Plan and Benefit

Air Compressor Power Saving Reform Plan and Benefit

1. The feasibility of power saving transformation of air compressor

The energy consumption of air compressors is obvious to all. The okmarts.com high-pressure fan power saver developed by okmarts.com based on the principle of frequency conversion can save electricity for all motor-driven air compressors. The overall power saving effect is remarkable, with a power saving rate of 20-50%.

Now take the actual transformation of okmarts.com for a limited company as an example to illustrate the following:

The electric company currently has 4 fully automatic production lines and another 80 injection molding machines. The compressed air required is provided by a set of compressors. The plant's gas supply system has four 380V compressors, of which two 37KW always work, and the other 55KW and 45KW are put into use in different time periods according to the gas supply situation. Due to the lack of compressor design and uncertain factors in the production process, this air compression system has the following defects:

Waste electrical energy. The working pressure of compressed air on the production line is required to be 3kgf/cm2, and the pressure on the main gas pipeline is kept at 3.2kgf/cm2. Since the air cannot be constant, in fact, the operation of two 37KW air compressors can basically meet the requirements, and the operation of three air compressors will cause frequent emptying and deflation, which is a serious waste of electricity. Moreover, the system pressure often fluctuates in a wide range of 3kgf/cm2-4kgf/cm2, which affects the product quality of certain processes to a certain extent.

loud noise. When the air compressor is automatically vented and deflated, the noise is very loud, causing environmental pollution.

The grid has a big impact. Since the three air compressors all start and run at industrial frequency, the starting current of the machine can reach up to 630A or more, which has an impact on the power grid.

Fluctuations in air supply. Since the system cannot automatically adjust the air supply, fluctuations in the air supply have a certain impact on the quality of the product.

To sum up, the air compressor energy-saving system can be used to carry out technical transformation of the existing air compression system, and the PID control frequency conversion technology can be used to establish a constant pressure air supply system, so as to save electricity, reduce noise, reduce equipment wear, and reduce power grid Impact, improve power factor, stabilize product quality and other effects.

Principles of Power Saving Reformation of Air Compression System

1. Introduction to power saving principle

The energy-saving controller adopts frequency conversion technology and the latest PID control technology. It uses pressure sensor signals and related electrical control signals to control the motor speed of the air compressor according to the set compressed gas pressure value to maintain the air pressure at the required pressure value. The energy that does not have to be consumed is saved, so as to achieve the purpose of saving electricity.

The system adopts continuous program control, there is no large current impact phenomenon during frequent startup, and it can effectively protect the power grid.

2. Modification requirements

There are four compressors in the factory's air supply system, two of which are 37KW always working, and the other 55KW and 45KW are put into use in different time periods according to the air supply situation. According to the requirements of the factory, the air supply of the air compressor should be at a constant pressure, and the air supply pressure range is 0～1MPa; in addition to the two 37KW air compressors working at full frequency (power frequency), the other 55KW and 45KW can be switched into operation. The operating frequency is controlled according to the required air pressure.

3. Control method

The working principle diagram of the control system is shown in the figure below.

It can be seen from the figure that there are 1 55KW air compressor (1# pump), 1 45KW compressor (2# pump), and 2 37KW compressors (3#, 4# pump) included in the system operation. Two of them are operated at 37KW industrial frequency and cannot be adjusted in speed, and the other two are adjusted by frequency converters. According to the specific conditions of the air compressor in the factory, the motor drive equipment inverter uses a 55KW inverter, which can be adapted to two air compressors of 55KW and 45KW.

In order to realize the constant pressure gas supply on the gas pipeline, a pressure transmitter is installed on the gas pipeline to transform the pressure in the pipeline network into a 4-20mA signal and send it to an intelligent self-tuning PID regulator. The PID regulator changes its input 4-20mA signal into a 0-10VDC electrical signal, and controls the output frequency and output voltage of the inverter, thereby changing the speed of the motor. When the system is working, pumps 3# and 4# run at power frequency. If the pipe network pressure is not enough, the frequency converter controls the 2# pump to start working. If the pipe network pressure is still not enough when working at the power frequency state, the frequency converter will automatically switch to pump 1# , Make it run until the required pressure of the pipe network; when the pipe network pressure is too high, the 1# pump will stop running, and the inverter will automatically switch to the 2# pump. If it is still too high, the 2# pump will stop working, only 3# , 4# power frequency operation is sufficient. Thus, the air pressure of the main pipe is basically constant, and the purpose of constant pressure supply is achieved.

When the consumption of compressed air changes significantly and the system pressure reaches the set maximum or minimum value, the electrical contact pressure gauge installed on the gas main will send the detected signal to the logic switch controller as the system switch on/off. An important condition (but not the only) for the power frequency unit. When the system needs to be put into the power frequency unit, the system first comprehensively judges which unit is in the ready state (STANBY), then sends an alarm signal, and executes the start command after a delay; when the pressure is too high and needs to be stopped, manual interference is not necessary , The system directly issues a shutdown command to stop the unit.

Comprehensive benefit analysis

The okmarts.com high-pressure fan energy-saving controller can minimize the power consumption of the air compressor. Because of the stepless speed regulation control, the power consumption of the air compressor is closely related to the use of pneumatic equipment. After installing energy-saving controllers for air compressors to save electricity, we estimate that the overall energy-saving effect can generally reach 20% to 50%, and some air compressors can reach a higher level.

After the okmarts.com air compressor unit is modified, the following results have been achieved through actual measurement:

Energy saving: After the constant pressure air supply system is put into operation, the air pressure of the air storage tank can be kept within 2.5% of the set value, and the energy lost due to automatic emptying can be saved. After actual measurement, the energy saving rate reaches 40% At the same time, the power factor is increased to COSф>0.95, reducing reactive power loss;

Reduce noise and reduce environmental pollution: The constant pressure air supply system has realized frequency conversion control, which basically eliminates the situation of emptying and deflation, thereby improving the environmental pollution of noise;

Extend the service life of mechanical parts: After using the air compressor power-saving system, the air compressor runs under the power frequency most of the time, which can significantly reduce the wear of mechanical parts, extend the life of the machine, reduce maintenance costs and shorten maintenance time;

Realize soft start: reduce the impact of the starting current of the unit on the grid, and at the same time can flexibly repeat the start multiple times, avoiding the shortcomings of the self-coupling step-down start in this respect;

Realize constant pressure air supply: After the system is put into operation, it improves the reliability of air supply and the ability to adjust load changes, ensures a constant air supply pressure, and further ensures the stability of product quality;

Reliable operation, failure rate is almost zero: the system is equipped with overload, loss of voltage, undervoltage, overcurrent, lack of equal protection functions, reliable operation;

Easy to operate, failure does not affect production: After the energy saver fails, it can automatically stop and send a failure signal. At the same time, it can be switched to mains to make the air compressor run normally without affecting production.