Summary of energy saving for compressor users

Summary of energy saving for compressor users

Compressor is a big power consumer, and its operation in production and life will cause a lot of power consumption. It is necessary to study compressor energy-saving technology. Now, not only compressor manufacturers are studying energy-saving technology, but also professional users are studying energy-saving technology. In actual operation, they have discovered many energy-saving solutions that are not suitable for their own working conditions and existing problems. Let's take a look at a summary of energy saving from a compressor user!

　　 Compressor operation energy saving

　　1. Problems in compressor operation

　　1.1 Low output and high energy consumption. Many industrial compressors limit the compressor power due to energy saving considerations, resulting in the compressor's compression capacity being lower than the design value, especially when the load increases in summer, the throughput will be significantly reduced. Due to the limited heat dissipation capacity, other equipment in the production line cannot be fully loaded. Operation reduces production efficiency.

The operating mode of two compressors in parallel has low operating efficiency and poor stability. Two compressors working in parallel can significantly increase the total flow, but the working flow of a single compressor is lower than that of a single compressor, so each compressor The working efficiency of the compressor has dropped. The total compression flow of the parallel connection of two machines is smaller than the flow of independent operation, and the flow increases after the parallel connection, the pipeline resistance loss will increase, and the safety of the unit will also be affected.

　　1.2 The unit is running poorly. This problem is mainly manifested in the compressor operating cycle difficult to meet the design requirements, unstable operation in summer, frequent failures, etc. Some compressor equipment has been running for a long time, and the mechanical, electrical and instrumentation components have frequent failures. It is difficult to achieve the crew chief by means of post-maintenance. Stable operation without failure in time, failure is prone to cause the compressor to stop and affect production safety.

　　1.3 Operation and maintenance costs are high. The maintenance cost of the old compressor is very high. When the two compressors are in parallel, the two compressors will have to spare one set of faulty parts. The cost of double backup is also caused by redundancy and waste of some spare parts.

　　2. Compressor energy adjustment and energy consumption

Compressors are generally selected according to the actual cooling requirements of the design conditions. Under normal circumstances, the compressors work throughout the year, spanning extreme weather in winter and summer, so they face a relatively complex external environment, and it is inevitable between the actual operating conditions and the design plan. There is a certain deviation, so the compressor power should have a proper margin.

　　 At this stage, compressor energy adjustment mainly includes intermittent control operation, suction adjustment, cylinder unloading, bypass adjustment and stepless speed adjustment. Among them, the intermittent operation of the compressor is a relatively common mode of operation. When the ambient temperature is higher than the set temperature, the compressor will start to run, and when the ambient temperature drops below the set temperature, the compressor will stop working. This working method is suitable for situations where the ambient temperature is relatively stable and the load is not large, but in actual use, the ambient temperature does not stabilize at any moment. Under extreme weather and complex working environments, various production activities will cause changes in cooling capacity, frequent temperature changes, and frequent start and stop of engines, which will result in greater energy waste. The instantaneous current of the generator will pollute the power grid, increase power grid fluctuations, and affect the life of the compressor. Therefore, frequency conversion technology has also been more used in compressors.

　　 3. Compressor frequency conversion energy saving

　　Under certain working conditions, the compressor cooling capacity is proportional to the mass flow rate. The basic idea of ​​frequency conversion adjustment is to adjust the mass flow rate by changing the compressor motor speed, thereby changing the total unit cooling capacity.

The system power consumption is related to the characterization adjustment method, and is also affected by the cooling capacity of the refrigeration device. The refrigeration system heat load is reduced. The cold storage control system will reduce the compressor speed through the inverter, thereby reducing the refrigerant mass flow, reducing the refrigerant condensation temperature, and increasing High evaporation temperature, thereby reducing the total cooling capacity. Moreover, the speed of the frequency conversion motor decreases, the friction work of the compressor decreases, and the adiabatic efficiency also increases, which is also helpful to reduce the K value. In the partial load state, the compressor motor speed decreases and KQ decreases, which can greatly reduce the system power consumption.

　　 Compressor energy saving technology

　　1. Optimization of compressor control process parameters

　　1.1 Suction pressure adjustment. Choosing the right suction pressure can effectively reduce the power consumption of the compressor. In general, the lower the suction pressure, the greater the energy consumption, especially the suction pressure of the compressor section. Therefore, the suction pressure of the compressor can be appropriately increased, and a high-efficiency cyclone inlet separator can be added in the first stage of the suction to further eliminate the resistance of the intake pipe network, and obtain a higher suction pressure while ensuring sufficient processing air volume.

　　1.2 The pressure drop between compressor sections is reduced. The pressure drop between compressor sections is also an important reason for compressor power consumption. In order to reduce the pressure drop between sections, high-efficiency heat exchangers can be used to replace inter-stage coolers to reduce unnecessary piping equipment and elbows, while improving operating conditions and reducing the degree of cooler fouling.

　　2 Optimization of compressor structure design

　　2.1 Ternary flow impeller. The ternary flow impeller is an impeller structure specially designed for gas flow. Large compressors generally adopt this structure. The existing impeller can also be modified to have the characteristics of a ternary flow impeller, which significantly improves the performance of the impeller. Related theoretical research and trial operation prove that the use of ternary flow impeller can increase the operating efficiency of the impeller by up to about 10%, and the cost of rebuilding the original compressor impeller is lower. However, it can significantly increase equipment production capacity and improve economic efficiency, and the energy-saving performance of the compressor will also be significantly improved.

　　2.2 Impeller polishing. There is a direct relationship between the surface roughness of the impeller and the loss of the wheel set. The surface finish of the impeller can be improved by means of precision casting, precision turning and grinding and polishing. There are many impeller polishing methods, including sandblasting, polishing wheels, liquid polishing, abrasive belt polishing, etc. Generally, the appropriate polishing scheme is selected according to the actual structure and material of the impeller. For impellers with a relatively large surface area, abrasive belt vibration grinding and polishing can be carried out, while impellers with complex structures, multiple cavities and bosses can be liquid polishing.

　　2.3 Compressor return flow control. In order to avoid the problem of compressor surge during operation, the compressor is equipped with an anti-surge control mechanism. Under normal process parameters, the state curve is drawn by monitoring the operating parameters of the unit, and the surge control line is calculated according to the surge line. In this way, the surge flow control point is obtained, and the return flow of the compressor is controlled by the comparison with the inlet flow to ensure that the compressor can obtain sufficient working gas. The compressor reflux manual control can be modified to automatic control, and a more accurate anti-surge control system can be applied to reduce the energy consumption of the unit.

　　2.4 Comprehensive optimization of pipeline layout. In order to further reduce the pressure drop in the pipeline, the pipeline layout needs to be adjusted to improve the rationality of the circuit layout. Pressure loss can be used to evaluate whether the pipeline layout is reasonable. If the pressure difference between the inlet pressure and the outlet pressure does not exceed 5%, it means that the compressor system pipeline layout planning is more scientific. In the pipeline, the equipment structural parts that can cause pressure loss mainly include desiccant, cooler, control valve, elbow, etc. The pressure loss of the desiccant, control valve and cooler can be measured according to the pressure loss standard. The pressure loss of the elbow is approximately 8-10 times the pressure loss of the equal diameter pipe. Through the accurate calculation of the total pressure loss of the pressure loss equipment, the total pressure loss of the pipeline can be reduced. Pressure loss.

　　 In addition to the optimized design, the daily use and maintenance of the compressor also have a great influence on the energy-saving effect of the compressor. In daily work, it is necessary to adopt scientific control methods to adjust the compressor, and cooperate with preventive maintenance strategies to reduce the failure rate of the compressor and maintain the normal performance of the compressor, so as to give full play to the energy-saving advantages of the compressor.

　　 3. Frequency conversion technology

　　Traditional compressors generally reduce the energy consumption of the compressor by controlling the flow and pressure process to achieve the purpose of energy saving. Generally, it is controlled by valve throttling, bypass return, and emptying. These adjustment methods have significant effects and simple operation, but they will increase pipe network loss and energy waste. The frequency conversion speed regulation technology uses the frequency converter to control the speed of the compressor motor, change the flow quality, and there is no valve throttling loss, thereby improving the energy utilization efficiency.

The application of variable frequency speed regulation in the compressor greatly improves the energy-saving performance of the compressor. The compressor speed is adjusted according to the output signal of the flow sensor, so that the compressor can accurately output the reflux flow required at the present stage, and achieve high-precision flow adjustment. To ensure the safe and efficient operation of the compressor, while saving energy, it also strengthens the unloading capacity of the compressor, reduces the operating noise, the equipment wears down more slowly, and the power factor is significantly improved.

　　4. Centralized control and heat recovery

　　 In many cases, compressors are not in stand-alone mode, but many compressors work at the same time. Therefore, in energy-saving transformation, the application of centralized control technology to achieve centralized control of multiple compressors has become an effective measure to reduce energy consumption and save energy. The number of compressors turned on is generally fixed. When the air consumption drops to a certain level, the working time or speed of the compressor can be reduced through centralized control. The air consumption continues to decrease, and the compressor with good performance and high power will stop working. , Eliminate energy consumption in unloaded state by completely shutting down, and centralized control to centrally adjust the working state of the compressor, thereby expanding the power range of the compressor, reducing the number of running compressors and reducing energy consumption.

The basic idea of heat recovery technology is that the high temperature oil of the compressor transfers heat to the cooling water through the heat recovery exchanger, and the cooling water is heated and stored in the heat preservation bucket to recover the working heat of the compressor. The heat recovery technology solves the heat dissipation problem of the compressor itself, and saves the equipment investment and energy consumption of the compressor's cooling fan. During work, monitor the temperature of the exhaust port of the compressor, and the heat recovery device will start to work if it exceeds 80°C to ensure that the compressor will not overheat, and the waste heat will be converted into hot water, which can be used for heating and other purposes.

　　 Conclusion

Energy-saving is an eternal theme in industrial production and daily life. Compressor energy-saving technology is an energy-saving technology aimed at reducing the energy consumption of compressors. Through the optimization of compressor structure design and adjustment of operating parameters, and the application of new energy-saving technologies, it can be significantly Improve the energy-saving performance of the compressor and reduce the energy consumption of the compressor.