Discussion on energy-saving design of compressed air system in non-ferrous metal processing enterprises Xu Xiangjun (Suzhou Branch of China Color Technology Co., Ltd., Suzhou, Jiangsu 215026) Because of the characteristics of air compressibility, non-condensation, non-hazard, easy to obtain and easy to transport, Non-ferrous metal processing enterprises, compressed air has been used as an important and indispensable power source for various process equipment, pneumatic tools, instrumentation detection, automatic control, etc. However, the process of producing compressed air itself needs to consume a large amount of primary energy such as water and electricity. For non-ferrous metal processing enterprises, the consumption generally accounts for 7-10% of the total cost. Therefore, how to make reasonable gas supply, Energy conservation is also the responsibility of every power design engineer.
The compressed air system of non-ferrous metal processing enterprises generally consists of two parts: a compressed air station and a pipe network. Therefore, in order to do a good job in energy saving and consumption reduction, we must start from the above two aspects. The following are the summary of energy saving and consumption reduction measures for compressed air systems in color metal processing enterprises.
1 The equipment for air compressors is selected. Most of the piston air compressors used in the past have complex system structure and pressure control technology. The system pressure is unstable, the maintenance cost is high, and the management is difficult. 20th century After the 1990s, it has gradually been replaced by other types of compressors, and few are used.
At present, for small and medium-sized gas (the total gas consumption is about 200m3/min), the screw air compressor is the main type of machine. The screw air compressors currently on the market are classified into ordinary single screw air compressors, energy-saving air compressors and variable frequency screw air compressors according to the unloading characteristics. The main difference is that the shaft power consumed by the air compressor is different when the amount of compressed air changes. Ordinary single-screw air compressors use the unloading method of intake interception. When unloading, they still consume large shaft power, which is 70% higher than the shaft power at full load. Energy-saving air compressors generally use intake interception and pressure relief. Unloading method of motor switch combination. When unloading, the motor stops running. When it is unloaded to the set value, the motor can start automatically, thus achieving better energy saving effect. The variable frequency screw air compressor can adjust the speed of the motor at any time according to the change of the actual gas consumption through the variable frequency controller. The lower the gas consumption, the lower the motor speed and the lower the shaft power consumption. Non-ferrous metal processing enterprises, due to the characteristics of the gas used in their process equipment, except that the rolling mill equipment is a relatively constant continuous gas, other equipment is not quantitative phased gas, so the total gas consumption fluctuates at any time, in the configuration of screw air pressure When the machine is used, the energy-saving air compressor should be used preferentially. At the same time, in combination with the specific situation of the gas flow fluctuation, a variable-frequency screw air compressor can be set, which can effectively reduce the shaft power loss when the gas consumption is small.
To achieve the purpose of energy saving and consumption reduction.
With the launch of large-scale aluminum processing projects in China in recent years, the total gas consumption of enterprises has also increased correspondingly. The total amount of compressed air used by some enterprises has reached 500m3/min. The use of screw-type air compressors alone will result in disadvantages such as excessive compressed air station buildings and complicated piping in the stations, resulting in increased capital investment and no energy savings. The combined air supply mode of the centrifugal air compressor and the screw air compressor can be considered, and the compressed air continuously used for the constant amount of the rolling mill and the like is supplied by the centrifugal air compressor, and the other equipment used for the non-quantitative intermittent use of the gas is driven by the screw. Air compressors are available.
It can reduce operating power consumption, save capital investment, and greatly reduce post-operation and maintenance costs.
2 In the design of the compressed air station, when the outdoor suction air compressor is used, the indoor temperature is higher than the outdoor temperature due to the heat dissipation of the motor. The experiment shows that for every 5*C increase in the inlet temperature of the air compressor, the displacement of the compressor will be reduced by 1%, and the power consumption will also increase by about 4% at the same time, resulting in waste of energy. At the same time, in the heating area, if the indoor air intake is used, the indoor air intake of the air compressor will be supplemented by the outdoor air, which will increase the heating heat load during the heating season and waste energy. Therefore, in the design, outdoor suction should be used as much as possible; of course, in certain areas, such as hot areas in the south, indoors can be sucked in the summer and should be treated differently.
3 Appropriate reduction of system air supply pressure Air compressors have a common characteristic. The higher the exhaust pressure setting, the higher the shaft power consumed. The power consumption of the air compressor for producing lm3 pressure non-ferrous metal processing air has the following relationship with the exhaust pressure: for every 0.05MPa of exhaust pressure reduction, the power consumption of lm3 compressed air can be reduced by 0.004kwh. The processing enterprise produces about 264X104m3 compressed air meter every month, which can save 10560kwh of electricity. At present, the gas pressure requirement of most colored processing equipment is 0.4~0.6MPa, and the rated exhaust pressure of air compressor equipment is more than 0. Actual operation When most companies set the air compressor exhaust pressure to be about 0. 7MPa, the pressure delivered to the end of the gas equipment is about 0. Down the space. Therefore, under the premise of ensuring safe production of gas, it is very effective to save energy and reduce consumption by appropriately reducing the exhaust pressure of the air compressor.
4Introduction of PLC automatic control system Due to the real-time fluctuation of compressed air consumption in non-ferrous metal processing enterprises, after introducing PLC automatic control system, feedback information can be feedback by using gas volume change, and the air compressor can be controlled to control the air compressor to start or stop, thus making air pressure The air supply of the machine matches the total compressed air consumption of the plant. When the total amount of gas used in the plant increases, the pressure of the compressed air in the pipeline of the conveying system will decrease, and the PLC control system will automatically calculate the required number of air compressors, and then issue the command to open the required air compressor.
When the plant's gas consumption is reduced, the delivery system's compressed air pressure will increase, and the PLC control system will reduce the number of operating air compressors by the same method. In this way, not only can the energy loss caused by unnecessary air compressors be greatly saved, but also the manual management is facilitated, and the unattended automatic management is realized. Can achieve better energy saving results.
5 Strengthening the management and maintenance of equipment and transportation system In the design of compressed air system, the leakage coefficient of the common coefficient 1.2~1.4 *1* is used. When the total length of the pipeline is less than 1km, take 0.1; when 1.5km, take 0.15; At 2km, take 0.2 to 2 gas equipment wear coefficient 0.15 * Unexpected consumption coefficient 0.1 From equation (1), it can be seen that 15 ~ 20% of the compressed air of the compressed air station is leaked by the pipeline and equipment wear The consumption, so the maintenance and maintenance of the piping system and equipment is very obvious for the energy saving effect of the compressed aerodynamic system.
At many factory sites, we often find a lot of pipe joints, because the seal is not strict, you can feel the pipe leaking by hand or ear. Pipe network leakage should be reduced by timely repairing leaking holes, changing gaskets, and cutting off unused local pipe networks during non-working hours.
Maintenance of air compressor equipment is also a guarantee for safe and energy-saving operation of the system. The quality of the maintenance directly affects the operating efficiency of the machine. The air compressor does not repair some minor faults in time, and the work efficiency will be reduced by 5~7%. Therefore, strengthening equipment maintenance, eliminating operational faults in time, ensuring that the equipment is always in the best operating state is also an effective way to save energy and reduce consumption.
6 Conclusion The energy conservation of compressed air systems in non-ferrous metal processing enterprises is a topic of common concern for engineering design and enterprises, and it has a direct relationship with the cost of final products. How to do a good job in energy-saving design of compressed air system, reduce the cost of products for enterprises, and maintain good competitiveness in market competition is our unremitting efforts in the future.
Our company will grow in scale and strength continuously and become the one of mostly partner from that manufacture in China offset printing plates, graphic- arts films, flexo graphic printing plat offset rubber blandigital printers, prepress system
solutions and consumables supply toserve printing industry from
every item.
Offset Ctp Plate,Processless Ctp Plate,Thermal Ctp Plate Agfa,Digital Thermal Plate
SUZHOU HUAGUANGBAOLI PRINTING PLATE CO.,LTD , https://www.huabaoiguang.com