Vaasa Air Compressor Renewal Plan

Shenzhen Wasa Automation Equipment Co., Ltd.
Air compressor energy-saving benefit analysis program
Technology Innovation People-oriented
table of Contents
I. Introduction
Second, the air compressor system application industry
Third, the screw air compressor system works
IV. Analysis of unreasonable operation of conventional air compressors
V. Principle of energy-saving renovation of air compressor system
6. Energy-saving Analysis of Air Compressor System
VII. Advantages of Air Compressors after Switching to Power Saver
Eight, 75KW air compressor energy efficiency analysis
IX. Direct economic benefits and implied economic benefits after energy-saving transformation
I. Introduction
On November 11th, 2011, Shenzhen Vaasa Technology Co., Ltd. technical and business personnel visited your company's head of the injection molding department Liu Lili, and brought your company's technical staff to participate in the transformation of our company's brothers near your company. In the course of the visit, the unit focused on the workflow and energy saving principle of the vertical injection molding machine.
After returning to your company, you communicated and exchanged with Liu Lili of your company's plastic injection department to learn more about your company's products and processing technology. Your company mainly produces wire rods, and the production equipment is mainly small-tonnage vertical injection molding machines. The vertical injection molding machine has a lot of energy waste during the processing of the product. According to the experience of the past transformation, after installing the Vasa variable frequency power saving, it can achieve 30-60% energy saving effect. At the same time, it can reduce the power loss of the line and improve the use efficiency of the transformer.
In this case, the analysis of power saving transformation of your company's vertical injection molding machine is now available for reference by your company's decision makers, so that we can better serve your company in power saving.
Second, the air compressor system application industry
In industrial and agricultural production, a certain amount of compressed air is often required. For example, electronics, plastics, hardware, chemicals, wood, textiles, pharmaceuticals, paper, and a large number of systems that require pneumatics, so these industries have installed air compressors. Power range from 7.5KW to 280KW. This equipment consumes a large amount of electric power during operation, which increases the production cost and has a great noise. It often requires equipment maintenance. Therefore, it is imperative for the compressor to save electricity.
Third, the screw air compressor system works
Screw type single-stage compressed air compressor, its working principle is a pair of mutually intermeshing yin and yang rotor (or screw) in the cylinder, so that the air between the rotor slots continuously produce a periodic volume change, air Then, it is transported along the axis of the rotor from the suction side to the press-out side to realize the entire process of suction, compression and exhaust of the screw-type air compressor. The air inlet and the air outlet of the air compressor are respectively located at both ends of the housing, and the female rotor and the male rotor are driven and rotated by the main motor.
The general air compressor startup method uses star-angle decompression to start the full-pressure operation. The workflow is: press the start button, the control system connects the starting valve coil and opens the oil-off valve, and the air compressor starts in the unloaded state. At this time, the intake valve is in the closed position and the purge valve is opened to discharge the pressure in the oil separator. After the buck starts, the air compressor starts loading and the system pressure starts to rise from 0 kg. If the system pressure rises to the pressure switch upper limit (usually 8 kg), ie the take-off pressure, the controller closes the inlet valve, the air separator deflate, and the compressor runs without load; until the system pressure drops to the lower limit of the pressure switch The value (usually 6 kg), that is, under the rebound pressure, the controller opens the inlet valve, the air separator valve is closed, and the compressor loading operation is unloaded from 6-6.5-7-7.5-8 kg. Cycle operation.
IV. Analysis of unreasonable operation of conventional air compressors
4.1. Although the star-angle decompression of the main motor is started, the current at the start is still 5-6 times of the rated current, which not only wastes energy but also affects the stability of the grid and the safety of other electrical equipment. If the change in the amount of gas used is greater, the frequent start and stop of air compressors will cause greater damage to the power grid and equipment.
4.2. The air compressor air supply pressure adjustment mode is controlled by the difference between the upper limit pressure value and the lower limit pressure value. The air compressor work flow is as follows: After the air compressor is put into operation, it runs at the rated rotation speed to inflate the air storage tank. When the air pressure of the air tank reaches the upper limit pressure value, the air bleed valve of the air compressor is unloaded, the pressure is stopped, and it is transferred to the no-load operation, but the air compressor motor still maintains the rated rotation speed and the unloading operation that consumes electric energy in vain; when the air tank When the air pressure is lower than the lower limit pressure value, the air release valve of the air compressor pulls in and loads, and the air tank is again pressurized at the rated speed until the stored air pressure reaches the upper limit pressure and is unloaded, and then goes into no-load operation, and so on. The air compressor has been in two operating states: one is full-load operation to do useful work, and the other is to perform unloading operation that consumes no power and consumes power in vain. In the entire operating time of the air compressor, the waste of electrical energy is very serious.
43. When the main motor is started and operated at industrial frequency, the noise during operation of the air compressor is large, and the wear of the motor bearings is also large, so the equipment maintenance workload is large and the maintenance cost is high.
V. Principle of energy-saving renovation of air compressor system
5.1. Principle of Constant Pressure Air Supply in Air Compression System
Variable frequency drive, PID closed-loop controller, air compression host, gas tank, gas supply pipe network, to form a set of gas supply system with constant pressure function
The air pressure adjustment process is as follows: Figure 1-2
According to the analysis, the pressure of the air tank is related to the air supply capacity of the air compression system and the air consumption of the user's pneumatic equipment. The balance between the air supply (Qg) and the air consumption (Qu) is as follows:
When the gas supply capacity Qg is greater than the demand gas quantity (Qu), the pressure (P) rises
When the gas supply capacity Qg is less than the demand gas (Qu), the pressure (P) drops
When the gas supply capacity Qg is equal to the demand gas quantity (Qu), the pressure (P) is not changed
From the analysis above, we can see that the contradiction between supply air volume and demand air volume can be reflected in the pressure change of the pipe network, and the pipe network pressure can be used as a parameter to control the balance between air supply volume and demand volume. Ensure that the pressure in the air compression system is constant, and that the balance between the air supply (Qg) and demand (Qu) can be maintained.
The air supply quantity (Qg) of the air compressor is related to the main motor speed of the air compressor. The variable frequency drive regulates the motor speed of the press according to the change of the air consumption, and thus adjusts the air supply amount according to the change in the air consumption. Balance, does not produce excess energy waste, but also ensures the stability of the use of gas pressure.
6. Energy-saving Analysis of Air Compressor System
Three-phase power-saving space can be obtained after power conversion of constant voltage and constant voltage
1, because the pneumatic equipment can work under the aerodynamic force of 5 KG, we can set the pneumatic pressure to about 6.5-7 kilograms on the gas tank to fully meet the needs of use, and also avoid the high pressure gas supplied by the host to the system (7 - Public 8 pounds) There is a large loss of wear and tear.
2. After constant pressure reformation, the pressure on the gas tank is stable. When the gas volume is reduced, the gas supply volume is reduced by reducing the speed of the variable frequency drive. When the gas volume is smaller, the reduced speed of the variable frequency drive is reduced. The greater the electric effect.
3. When the air compressor system is not reformed, the air supply pressure is in the range of 6-8 kg. It will follow the amount of air used, and will be stable at a certain pressure value. It will not be unloaded and will be operated under constant load. Due to the design, the air supply is usually larger than the air requirement, so it is usually stable at a pressure of 7-7.9 kg. It is usually called full load operation. If the constant voltage power saving transformation is carried out, a minimum pressure stabilization value can be set according to the pneumatic equipment. Under the condition that the pneumatic equipment is used, the loss of the high pressure gas from the host to the system for a long time is avoided.
VII. Advantages of Air Compressors after Switching to Power Saver
7.1. Lower operating costs
The operating cost of conventional compressors consists of three components: initial procurement costs, maintenance costs, and energy costs. Among them, the energy cost accounts for about 77% of the operating cost of the compressor. Through the reduction of energy costs by 44.3%, coupled with the reduction of impact on the equipment after the frequency conversion start, maintenance and repair volumes also follow, so the cost of sub-branches will be greatly reduced.
7.2. Improve pressure control accuracy
Variable frequency control system specific precise pressure control capability. The air pressure output of the compressor is matched to the amount of air required by the user's air system. The variable output compressor controls the output gas volume as the motor speed changes. Due to the increased precision of the frequency conversion control motor speed, it can maintain the system pressure change of the pipe network in the range of 3pisg, which is within the range of 0.2bar, effectively improving the quality of working conditions.
7.3. Extend the life of the compressor
The frequency converter starts the compressor from 0Hz, its starting acceleration time can be adjusted, thus reduce the impact that the electrical component and mechanical component of the compressor caused when starting, strengthen the reliability of the system, make the service life of the compressor prolong. In addition, the frequency conversion control can reduce the current fluctuation when the unit starts. This fluctuating current will affect the power supply of the power grid and other equipment. The inverter can effectively reduce the peak value of the starting current to the minimum.
7.4. Reduces the noise of the air compressor
According to the requirement of the working condition of the compressor, after the conversion of the variable frequency speed control, the speed of the motor is obviously slowed down, so the noise during the operation of the air compressor is effectively reduced. On-site measurements showed that the noise dropped by about 3 to 7 dB compared with the original system.
Eight, 75KW air compressor energy efficiency analysis
8.1. Power Saving Determination
Energy-saving degree = power frequency 24-hour power consumption - the difference between the 24-hour power consumption in the energy-saving state.
Energy-saving rate = (24-hour power consumption in power frequency state - 24 hours power consumption in energy-saving state) ÷ Power frequency status 24-hour power consumption Energy-saving equipment Investment efficiency analysis
8.2, air compressor motor power 75Kw: A = 75KW
l The daily power consumption (B) is calculated as 70% of the load rate: B=A×0.7×24=75×0.7×24=1260 degrees
l The electricity fee is 0.8 yuan/degree and the daily electricity charge (C) is: C=B×0.75=1260×0.8=1008 yuan
l According to the minimum energy saving rate of 20% after transformation
Monthly electricity savings (D): D=C×20%×30=1008×20%×30=6040
The annual electricity saving (G) is: G=D×12=6040×12=72576
8.3. Total investment of a set of 75KW Power Saver (E): 37,500 yuan
8.4 Recycling Period (F): Investment Amount / Monthly Recycling Funds
F=E÷D= 37,500 ÷ 6040 ≈ 6-7 months
IX. Direct economic benefits and implied economic benefits after energy-saving transformation
9.1. Direct economic benefits
All the main components of the system are imported. The service life of the system is 8-10 years (calculated according to the minimum service life of 8 years), and the annual system maintenance cost is 10%. This energy-saving technological transformation brings about total
H = (GG × 10%) × 8 = (72576-72576 × 10%) × 8 = 522, 547 yuan.
9.2. Implicit economic benefits
According to the energy-saving principle of the Power Saver, in addition to the intuitive power-saving benefits, the system's operating life for the protection of equipment and lines is prolonged, the heat output of the device is small, the operating efficiency is increased, and the maintenance cost is reduced. For its part, it is also a non-negligible economic benefit.
In particular, after the transformation through electricity saving, the electricity consumption is reduced by 20-40%, which reduces the power loss in the distribution network and improves the power efficiency of the transformer. The implicit economic benefits brought about by the investor are also A substantial gain.