Application of the most popular frequency converte

2022-08-11
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Application of universal frequency converter in the cement industry

through understanding the cement manufacturing process and the actual investigation of some cement plant production equipment, some equipment in most cement plants, especially some high-power equipment, are dissatisfied with the load most of the time in the production process, and the automation degree of equipment operation is quite low, which is almost completely adjusted manually, such as the air supply system of mechanical shaft kiln, pelletizing pre watering system, raw meal homogenization feeding system Cement powder separation system, machine shaft kiln unloading system, etc. Through long-term follow-up research on the above systems and combined with the practical experience of transforming dozens of cement production lines, the engineering and technical personnel of puchuan company and the Co., Ltd. have developed a relatively mature transformation scheme for the frequency conversion and speed regulation control of the five major production systems of the cement plant. This scheme has the advantages of less investment, convenient installation, commissioning and control, reliable operation, obvious power saving effect, and improved the automation degree of the production process and the accuracy of processing technology, It is welcomed by the cement manufacturing industry

the company has three cement production lines. First, we began to carry out frequency conversion transformation on a 132 kW powder concentrator fan in April 2002. After a period of testing, it has been proved that the energy-saving effect is particularly obvious. Therefore, since the second half of last year, we have successively carried out frequency conversion transformation on the blower on the shaft kiln (one 245 kW, two 215kw), powder concentrator, powder concentrator fan, tray tower feeding and other motors, and have invested about 1.3 million yuan so far, A total of 130 motors ranging from 1.5KW to 250 kW have been transformed. The actual test results after the transformation prove that the overall investment can be recovered by saving electricity charges in a few months, and it can also be in a more powerful position in the market competition with lower production costs in the future production and operation. The actual effect of the frequency conversion transformation scheme of the above systems is analyzed based on the transformation of the company

first, the frequency conversion transformation device of the air supply system of the machine shaft kiln

like other old cement enterprises, the air supply system of the machine shaft kiln meets the different air consumption during sintering by adjusting the backward mechanical adjustment method of the opening angle of the wind deflector. The shortcomings of this operation mode are obvious: 1. Serious waste of electric energy; 2. Poor adjustment accuracy; 3. The starting current has a large impact on the electricity; 4. The speed of motor and fan is high and the load intensity is heavy; 5. The mechanical impact is large when starting, and the service life of the equipment is low; 6. High noise, serious dust pollution, etc. The reformed variable-frequency air supply system is to add a set of variable-frequency circuit in parallel with the original circuit on the basis of retaining the original air supply system to form a dual circuit convertible control system, and install the speed regulating device of the frequency converter on the kiln to adjust the air volume during sintering by adjusting the speed of the motor (fan). Its features: 1. Good power saving effect (because the power consumed by the motor is available for testers to choose their favorite report format (the built-in excel report function of the test program expands the pattern of the previous single professional report) is proportional to the third power of the motor speed. After the transformation, the motor runs at about Hz most of the time, which can meet the air consumption, and the power saving rate is more than 20%; 2. With soft start function, it can reduce the load intensity, prolong the service life of the equipment, and the starting current is small, which is equivalent to increasing the capacitance; 3. The accuracy of air volume adjustment is accurate and convenient; 4. Bypass ventilation is not required to reduce cement dust pollution

II. Pelletizing water supply system

the raw material pelletizing process is one of the key processes that affect the sintering quality of clinker that the friction wheel surface in the water gearbox must not be oiled or splashed with oil sludge, in which the proportion of water and material directly affects the quality of pelletizing. After the application of the frequency converter, the speed of the pelletizing pre dosing pump can be stepless adjusted by tracking the raw material supply, so as to realize the full-automatic closed-loop control. The mixing of material and water is stable, the pelletizing effect is good, and the cement sintering quality is greatly improved. The transformation of this system is mainly to improve the degree of automation and the level of manufacturing technology. Due to the small power, the effect of power saving is also second

III. The effect of raw meal increase is to homogenize the feeding system first

after the system is transformed with frequency conversion, the feeding motors at all feeding ports are synchronously adjusted with frequency converters to feed in equal proportion, so as to improve the homogenization effect, which is also considered from the perspective of manufacturing technology

IV. cement powder selection system

the working principle of cement powder selection system is to adjust the rotation speed of powder concentrator and fan according to the different grades of cement produced, so as to select cement products with different fineness. The number and angle of fan blades on the fan shaft of the old-fashioned powder concentrator should be adjusted, and the required powder fineness should be achieved through comparative test; The new powder separation system consists of a powder separator and a powder separation fan. The powder separator is regulated by a slip motor, and the powder separation fan adjusts the air volume by adjusting the angle of the wind deflector. These two systems have the disadvantages of complex operation process, poor adjustment accuracy and serious waste of electric energy. In particular, the slip machine not only consumes electricity, but also has high expansion rate of slip skull and difficult maintenance due to the serious dust in the cement manufacturing environment. After the frequency conversion transformation, no matter the old system or the new system, as long as the motor is adjusted to a specific speed, the particles with the required fineness can be selected. While saving electric energy, it also achieves continuous and automatic production, which not only improves the labor efficiency, but also reduces the labor intensity, and the comprehensive benefit is obvious

v. shaft kiln unloading system

in order to balance the feeding, air supply and unloading in the cement sintering process, the shaft kiln generally uses the slip motor (electromagnetic speed regulating motor) as the power of the tray tower unloading device. The motor not only cannot meet the needs of the cement production site environment, but also consumes about 20% more power than the series motor at the same output speed, and there is more difference when reducing the speed, Therefore, after using the variable frequency speed regulation system to replace the slip speed regulation, the above shortcomings can be solved, and the speed regulation performance is much higher than the slip speed regulation motor. While saving electricity, the maintenance cost is also greatly reduced, which is widely used in various industries

the frequency converter is used to control the motor that can adjust the speed. It not only saves a lot of electric energy, but also has the soft start function. At the same time, it reduces the starting current and running current of the motor, reduces the load intensity of the whole power system and mechanical system when starting and working, and prolongs the service life of mechanical components. In addition, the frequency conversion transformation of the slip motor improves the protection level of the motor and reduces the motor failure rate caused by bad environment

foam granulator VI. unexpected harvest

due to the decrease of current when the frequency converter works and starts, it provides a necessary guarantee for the start-up of other equipment, which virtually increases the power capacity of the factory, which is particularly beneficial for occasions with unstable electric voltage and small power capacity. After the overall transformation like Tianma Cement Co., Ltd., 200KVA can be saved

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