Application of Sunwoele HFV3000series1100kW high-power inverter in belt conveyor for energy saving

Abstract: From the mine to the production plant, as long as there is a certain height difference and a certain potential energy, VFD (Variable-frequency Drive) can be used to excite the motor to generate electricity. VFD (Variable-frequency Drive) is a regenerative energy transmission system , which can feed regenerative energy back to the grid. The general situation is that it is continuously transported 24 hours a day, the amount of ore transported is large, the power generation of the motor is also large, and the power feedback is also large. Judging from the current situation of domestic mines in China, large-tonnage mining trucks are basically used to transport ore from the mountain to the mountain, which not only wastes oil, pollutes the environment, but also takes up a lot of cultivated land, which is a pity . Using a VFD (Variable-frequency Drive) to drive the belt conveyor with a generator to transport ore can recover a large amount of electric energy, reduce production costs, and improve the competitiveness of enterprises. This method is worth promoting.

I. Overview

In the new dry process cement production line, the limestone raw material mines are located on the mountain several kilometers away in a straight line. The traditional transportation method is to use large-tonnage mining trucks to transport ore from the mountain to the next mountain. In order to ensure the normal progress of production, it is necessary to build a road that can be used by mining vehicles. As long as the cement production line does not stop, mine trucks will continue to transport limestone from the mountain to the foot of the mountain. This road should be able to withstand the rolling of large-tonnage mining vehicles. Its length is more than several kilometers, it covers a large area, and naturally requires a large investment, and it consumes a lot of oil during transportation. Considering the maintenance of equipment and roads, the operation cost is high, and the cement production cost increases, which is not conducive to market competition. Considering that the potential energy of the limestone is constantly decreasing during the process of transporting the limestone from the mountain to the downhill, in order to reduce the production cost, the potential energy of the limestone itself can be used to safely transfer the limestone from The mountain is transported to the bottom of the mountain, such as the use of more belt conveyors now. The belt conveyor described in this article is not only used as a tool for transporting limestone, but also uses potential energy to generate electricity. The energy-saving efficiency is not trivial, and it is of great significance to reduce the power consumption of cement production.

2. Belt conveyor

The belt conveyor is mainly composed of steel cord belts, rollers, rollers, intermediate frames and propellers. It is widely used in various industries such as mining, metallurgy, coal, ports, power stations, building materials, chemicals, light industry, and petroleum. To convey loose materials or finished items, according to the requirements of the conveying process, it can be conveyed by a single unit, or multiple units can be formed or combined with other conveying equipment to form a horizontal or inclined conveying system to meet the needs of different layout types of operation lines. The belt conveyor has the characteristics of simple structure, standardized components, convenient maintenance, large conveying capacity, simple operation and maintenance, low operating cost, and wide application range. Long-distance belt conveyor is a kind of large-capacity transportation equipment, which has the characteristics of continuous, reliable, high degree of automation, small equipment maintenance workload, can be networked with the factory's general control system for unified management, and the transportation line is arranged according to the terrain and occupies less cultivated land. ; At the same time, the material is relatively stable during transportation, with few dust spots and little environmental pollution.

A cement company has two 500t/d dry-process cement production lines. The limestone raw material is transported by a long-distance curved belt conveyor with a capacity of 1800t/h. The horizontal distance from the crushing station to the plant silo is about 5451m; the mine crushing station The floor elevation of the tipping platform is about 680m, the outlet elevation of the belt feeder of the crushing station is about 662m, the floor elevation of the cement plant at the end of the conveyor belt conveyor is 290m, the elevation of the discharge point at the head of the conveyor is 310m, and the conveying height of the conveyor is about -352m .

The above data shows that 1800t of limestone was transported down 352m in 1 hour, from which the potential energy generated by the material can be calculated as:

3. Belt conveyor control scheme

1. Technical parameters of belt conveyor

Capacity of belt conveyor: 1800t/h

Horizontal projected length of belt conveyor: 5451m

The maximum lifting height of the belt conveyor: -352m

Motor rated power: 2880kW

Motor voltage: AC three-phase 690V (6000V)

Tape width: 1400mm

Tape model: ST3150

Tape running speed: 3.3m/s

The maximum downward movement angle: 20 degrees

Generating power: 1200kW

Material particle size: 80mm.

2. Control scheme:

The long-distance down-conveyor belt conveyor is divided into two sections, and two AC motors are installed at the tail of the belt conveyor, using tail-side drive.

(1) High-voltage AC motor direct drive scheme

The motor directly drives the belt conveyor down without a reducer. When starting, especially in the case of starting with load, there will be a great mechanical impact, which may cause the tape to break, causing serious consequences. In order to realize the soft start with load, hydraulic brake is added during the starting process, which will greatly increase