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Energy-saving and consumption-reducing frequency conversion technology in cement industry plays an important role


Release time:

Oct 28,2013

Frequency conversion technology was born in response to the needs of stepless speed regulation of AC motors, which aims to achieve AC control by changing the frequency of AC. With the development of computer technology and power electronics technology, the application of low-voltage inverter has also been rapid development. The use of frequency converter can improve the control accuracy of machinery, production efficiency and product quality, while reducing energy consumption. The energy-saving effect of using frequency conversion technology is remarkable. Since the research and development, the frequency conversion technology has achieved remarkable energy-saving effect in many production processes. The national "energy saving and emission reduction" 12th Five-Year Plan "requires the implementation of energy-saving transformation projects, and the energy saving of motor system is one of the main projects,

Frequency conversion technology was born in response to the needs of stepless speed regulation of AC motors, which aims to achieve AC control by changing the frequency of AC. With the development of computer technology and power electronics technology, the application of low-voltage inverter has also been rapid development. The use of frequency converter can improve the control accuracy of machinery, production efficiency and product quality, while reducing energy consumption.

Significant energy saving effect using frequency conversion technology

Since the research and development, frequency conversion technology has achieved remarkable energy saving effect in many production processes. The national "Twelfth Five-Year Plan for Energy Conservation and Emission Reduction" requires the implementation of energy-saving transformation projects. Energy-saving of motor systems is one of the main projects. It is required to implement energy-saving transformations such as frequency conversion speed regulation, permanent magnet speed regulation, and reactive power compensation for motor systems to optimize system Operation and control improve the overall operating efficiency of the system. The plan proposes that the operating efficiency of the motor system in 2015 will be increased by 2 to 3 percentage points compared with 2010, and a power saving capacity of 80 billion kWh will be formed during the "Twelfth Five-Year Plan" period. Therefore, since the "Twelfth Five-Year Plan", energy conservation and environmental protection as the core of my country's industrial economic development, while pointing out the direction for the sustainable development of my country's industry, it is also effectively stimulating the sustainable development of my country's inverter industry, making my country's inverter industry Continuously expand the market share of the industry, and become an important basis for the development of my country's industrial economy by virtue of strong development.

Frequency conversion energy saving is mainly used in the need to change the speed of the AC motor, change the characteristics of the drive machinery to meet the requirements of the production process, more applications in the fan, water pump. When the motor can only run at the rated speed, the drive machinery can only run at a certain rated speed. When the production process requires the adjustment of process parameters, the flow can only be forced to change by increasing (decreasing) system resistance, and the motor is always running under rated conditions, resulting in waste of electric energy. Such as fans, pumps and other equipment, the traditional speed control method is to adjust the air volume and water supply by adjusting the baffle and valve opening of the outlet (or inlet). In addition to consuming electric energy in vain, it also increases the system accessories and increases the probability of system failure. When using variable frequency speed regulation, if the flow requirement is reduced, the requirement can be met by reducing the pump or fan speed.

Overall, the inverter mainly through the power factor compensation and soft start two ways to achieve energy saving effect. Power factor compensation, due to reactive power will increase the line loss and equipment heating, coupled with the reduction of power factor led to the reduction of active power grid, a large number of reactive power consumption lines, equipment use efficiency is low, serious waste. After using the variable frequency speed regulating device, the filter capacitor inside the frequency converter acts, thus reducing the reactive power loss and increasing the active power of the power grid.

In terms of soft start and energy saving, the hard start of the motor will cause a serious impact on the power grid, and the requirements for the power grid capacity are also too high. When large current and vibration are generated during startup, the baffle and valve are greatly damaged, and the use of equipment and pipelines Life is extremely unfavorable. The use of the soft-start function of the inverter will make the starting current start from zero, reduce the impact on the power grid and the requirements for power supply capacity, extend the service life of equipment and valves, thereby saving equipment maintenance costs.

However, it should be noted that the use of the inverter should avoid the "small horse-drawn cart" problem. The reason for this problem is based on the working conditions of the design when it was put into production at that time, so that in order to save money in the design and installation, many places have adopted the setting of variable frequency power less than the rated power of the motor. However, with the development of technology and the change of process production conditions, the problem of "small horse-drawn cart" inevitably appears, resulting in the normal operation of the inverter. Therefore, during the trial period of the frequency conversion device, in order to prevent problems before they occur, detection and adjustment should be carried out in advance to avoid the above problems. In addition, the inverter is easy to enter the high-incidence period of failure after 6 to 10 years of normal use, and there are often failures such as component burnout, failure, and frequent action of protection functions, which seriously affect its normal operation.

Fan frequency control to reduce cement power consumption

The industry report pointed out: my country's inverter market is currently in a period of rapid growth, and it is widely used in textile machinery, air conditioning, elevators, metallurgy and other industries. In the past few years, China's inverter market has maintained a high growth rate. It is estimated that according to the demand of China's market, the market will be saturated and mature at least 10 years later. Therefore, China's inverter market has a broad space for development.

At present, China is vigorously promoting the concept of energy conservation and environmental protection. After a 6% shrinkage in the segmented market of the frequency conversion industry in 2012, it is gradually returning to growth. The investment of 4 trillion yuan in energy conservation and environmental protection further stimulates the development of the frequency conversion industry market. Taking the cement industry as an example, in the mechanical and electrical equipment of cement plants, centrifuges, water pump equipment, air compressors, powder separators, rotary kilns, ball mills, plate feeders, speed-regulating belt scales, coal feeding recliners, grate coolers, vertical kiln Roots fans, unloaders and other equipment that require AC speed regulation can use frequency conversion speed regulators to achieve the function of energy saving and consumption reduction. Among them, the fan regulation using frequency conversion speed regulation as a means of energy saving is widely used in various industries at home and abroad, foreign cement enterprises have widely used fan frequency conversion speed regulation to meet the different working state system regulation, in order to reduce power consumption costs. Exploring the energy-saving potential of fans has become a major measure to enhance the market competitiveness of cement enterprises.