In the metallurgical industry, there are many weighing and feeding systems with frequency application prospects and space, but which are widely promoted and accepted by many users are still mainly concentrated in the fan and circulating water pumps on two types of loads. Typical applications in the metallurgical industry load there are many kinds of, among which the batching junction main extractor fan, blast furnace blower and oxygen compressor power is larger, its running speed by different working conditions and change, energy saving transformation effect is obvious. The batch junction main extractor fan is of great interest to many EMC manufacturers for its retrofit due to the large energy saving space of the process.

A background

1.1 Process

Weighing feeding system in order to ensure that the iron content of iron ore supplied to the blast furnace is uniform, and to ensure the permeability of the blast furnace, it is necessary to make the iron ore concentrate output from the beneficiation process into a block of raw iron ore powder in the form of 10 to 25mm. Block making currently has two main methods: batching junction method and pelletizing method. The lumps obtained by the two methods are dosing junction ore and pelletized ore, respectively. At present to pumping process dosing knot is more, dosing knot machine is divided into belt and ring type.

Weighing and loading system batching process refers to the processing procedures and batching process system selected according to the characteristics of raw materials, which has a direct and important impact on the yield and quality of batching production. According to the inherent law of the batching process to choose the appropriate process and operation system, the use of modern scientific and technological achievements, to strengthen the batching production process, can obtain advanced technical and economic indicators, to ensure that the realization of high-yield, high-quality, low-consumption. The production process has the raw material acceptance, the ash blending, mixing, screening and crushing and solvent fuel crushing and screening, dosing, mixing, ignition, pumping batching knot, pumping cooling, crushing and screening, dust removal and other components. At present, the production is widely used in the belt-type air extraction batching machine to produce batching ore.

1.2 Energy-saving transformation

Weighing batching control system batching junction for 110m2 belt batching junction, the line is equipped with a Shanghai a batching system factory 10kV/5600kW brushed synchronous system, the load for the batching junction main extractor fan; the other two 10kV/710kW asynchronous batching system, the load for the batching junction ring cooler, one with a standby. At present, the main extractor fan starts and operates in the form of industrial frequency asynchronous buck-voltage soft operation with synchronous excitation.

The main extractor fan of this automatic dosage system production line is adjusted by baffle, the material thickness of the dosage junction is about 700mm, according to the permeability of the material layer, the opening degree of the main extractor fan fan is about 70%, and the negative pressure is maintained at -16kPa, which is subject to the guaranteeing of the finished product rate. Ring cooler to ensure the cooling effect shall prevail. This program mainly carries out frequency conversion and analysis on the main extractor fan of batching junction.

2.2 Weighing and batching system technical program

According to the site load situation, configure the high voltage frequency converter HD93-J100/7000-DN produced by Huichuan Company, which has the advantages of large design margin, strong overload capacity, convenient operation, reliable quality and so on.

1) Main circuit: adopting one-top automatic bypass program.

2) Frequency conversion operation mode: 1QF is the high-voltage switchgear on the user side, of which KM1 and KM2 are AC contactors, QF1 and KM2 are vacuum circuit breakers, and QF3 is vacuum circuit breaker.

3) Vacuum circuit breaker, electrical interlock between KM1KM2 and QF1. Automatic bypass cabinet frequency excitation cabinet and frequency converter supporting the provision of dosage systems and user-side high-voltage circuit breaker 1QF to retain the Party's original weighing and dosage.

4) When operating at working frequency, KM1 and KM2 are disconnected and the excitation knife gate is switched to the working frequency excitation system; QF1 is closed and the water resistance soft starting device is put into the working frequency circuit, and the startup, operation and shutdown process of synchronous batching machine are carried out according to the original logic.

5) When the frequency conversion is running, QF1 is disconnected, and the frequency conversion excitation system can utilize the CASGOOD special synchronous excitation control system, KM1 and KM2 are closed to switch the excitation knife gate to the frequency conversion excitation system. When the frequency converter is powered up, the circuit breaker 1QF is closed, and the HD93 high-voltage frequency converter starts up by dragging the synchronous dosing system to start up with the vector control of the electrically-excited synchronous machine.

6) When the frequency conversion stops, the "stop" command is given to the frequency converter from the site, and the frequency converter drives the synchronous batching system to decelerate to a complete stop, and then stops outputting voltage and current. Finally, break the circuit breaker 1QF at the site, notify the excitation device to extinguish the magnetization by its auxiliary contact, and turn off the power supply of the excitation device after extinguishing the magnetization. In case of failure, the frequency converter stops voltage and current output at the same time, immediately breaks the superior circuit breaker 1QF, and the main control of the frequency converter notifies the excitation device to extinguish the magnetization, and then puts it into the operation of industrial frequency.

(7) Control circuit: remote speed regulation, remote monitoring of operating frequency and output current, etc. are implemented in the operation box of the wind turbine room.

Third, conclusion

High-voltage frequency converter for synchronous batching system with a unique electric excitation synchronous machine vector mounted shaft encoder control mode, to solve the problem of high-power synchronous motor batching start-up difficulties, HD93 series in the field operation has become more convenient and simple. The good operation of the main extractor fan of the batching junction of this modification also strongly proves that the synchronous machine vector control technology of CASGOOD is more advanced than that of similar manufacturers. At present, HD93 series high-voltage frequency converter can be used in metallurgy, electric power, petrochemical, powder, building materials and municipal and other fields; the loads that can be dragged are fans and pumps, belt conveyors, air compressors and so on.