Application of the hottest alpha frequency convert

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Application of alpha frequency converter in blast furnace

I Preface

since the reform, China's national economy has developed rapidly, but the development of the energy industry is far from meeting the needs, and the state of the energy gap will not change for a considerable period of time. Therefore, the country focuses on the energy policy of paying equal attention to development and conservation. In particular, it focuses on saving valuable secondary energy - electric energy. The largest user of electric energy in China is the motor that benefits all amputees, accounting for about 50%, of which the power consumption of fans and pumps accounts for 30% of the total electric energy. The air volume and water volume of traditional fans and pumps are adjusted by dampers and throttle valves. When the air volume and water volume need to be reduced, the opening of the damper and valve decreases. When the air volume and water volume need to be increased, the opening of the damper and valve increases. Although this adjustment method is simple and easy, it has become a habit, but it is at the cost of increasing pipe loss and consuming a lot of energy on the damper and valve. And usually in the design, the design capacity of the user's fan and water pump is much higher than the actual needs, which is easy to form the phenomenon of "big horse pulling small car", which is often said, resulting in a large waste of electric energy

under the excellent form of constantly perfecting the market economic system, accelerating the reform and opening up and the western development, Kunming Iron and Steel Co., Ltd. seized the opportunity, accelerated development, widely absorbed the successful experience of domestic excellent iron and steel enterprises, optimized the process structure, vigorously promoted technological progress, energy conservation and consumption reduction, cleaner production, etc., so as to make the structure of iron and steel products more reasonable, significantly enhance the market competitiveness, and modernize and economize, A substantial leap has been made in the industrial process of high efficiency, which has made great contributions to the sustainable development of enterprises and the national energy conservation and environmental protection undertakings and economic development. If the flow is adjusted by adjusting the speed, we can fundamentally prevent the wave of electric energy. We have been working with various types of modified polycarbonate (PC) fees. In recent years, with the development of power electronics technology, frequency conversion and speed regulation technology has become more and more mature, Therefore, it is of great significance to promote the application of variable frequency speed regulation in fans and pumps to reduce energy waste

II Project overview

in 2005, with the successive commissioning of the reconstruction and expansion projects of Kunming Steel, the production scale of Kunming Steel has reached a new level, and the power consumption will also increase significantly. In view of the current tense situation of power supply, in order to meet the growing production and living electricity needs of Kunming Steel, on the basis of the "green lighting" transformation and other energy-saving achievements, Kunming Steel will actively explore and promote the use of frequency conversion energy-saving products for old systems and equipment, further improve the power utilization efficiency of equipment, and strive to make new breakthroughs in saving resources, reducing production costs, improving economic benefits, and protecting the environment,

the No.2 and No.3 blast furnace of Kunming Iron and Steel Co., Ltd. was built in the 1980s. The equipment has been transformed several times. Among them, the frequency converter is applied to the combustion supporting blower of the hot blast stove on the 300 cubic meter blast furnace. The motor parameters are as follows:

III Production process flow

1 The process diagram is shown in the following figure:

2 Operation profile

the hot air combustion fans of No.2 and No.3 blast furnaces in ironmaking plant are designed as one-to-one without standby, and the fans operate continuously for 24 hours. The vent valve is set at the outlet of the blast furnace to adjust the pressure and flow of hot air supplied to the blast furnace. The pressure is generally controlled at 5.0--5.4kpa. For a long time, the combustion supporting fans of the two blast furnace hot blast stoves have achieved flow control by adjusting the vent valve, so the system efficiency is low, the power consumption is large, and the waste of electric energy is serious. Due to the continuous and stable air supply required during normal production, the air volume and air pressure change little. At this time, the throttling loss can be eliminated through frequency converter regulation, and the operating efficiency of the fans can be improved at the same time, although the operating efficiency will be reduced due to the reduction of the motor load rate, However, due to the large drop in the operating power of the fan, the loss of the motor is also reduced, and finally the operating power of the motor is greatly reduced, so as to achieve the purpose of power saving

3. Due to the different working conditions of the two blast furnaces, taking the blower of the hot blast stove of No. 2 blast furnace as an example, during the normal ironmaking production of the blast furnace, due to the limited on-site test conditions, only the motor was tested

measured data: the average power of fan motor p=200.98kw

test condition: the fan operates normally, the opening of inlet air valve is about 85%, the opening of vent valve is about 5%, and the hot air pressure is 5.2kpa

IV Transformation scheme:

1 Principle of variable speed regulation:

according to the basic principle of electromotology, the principle of motor speed meets the following relationship:

n= (1-s) 60F/P

where: P-number of motor poles, f-motor operating frequency, s-slip

it can be seen from the formula that the synchronous speed n1 of the motor is proportional to the operating frequency n of the motor, because the slip s is generally small

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