Application of frequency converters in energy-saving retrofitting in the mining industry
With the release of the "12th Five-Year Plan" document, all sectors have embarked on a new round of development sprint. During the "12th Five-Year Plan" period, the state requires enterprises to reduce energy consumption per unit of GDP by 20%. Currently, electricity is the main energy source for household life and business consumption in China, especially for the mining industry. Every summer, peak electricity consumption occurs frequently, leading to power shortages and severe impacts on industrial electricity production. For them, how much they wish their electricity bills for this month or quarter could be lower! Electricity consumption is undoubtedly a major headache for the mining industry, and they especially hope for equipment that can solve their problems.
Beijing Xinno Hengcheng Technology Co., Ltd. is willing to share with everyone, out of a sense of social responsibility, the effects of our Xinno frequency converters in the mining industry in Hebei Province, and to discuss cooperation in this field. This article is written to discuss this with friends from all walks of life.
In the mining industry, the jaw crusher is undoubtedly the leading machine. A jaw crusher is a piece of equipment used in mining to break down large pieces of ore into smaller stones. It primarily relies on a vertically fixed jaw plate and an inclined movable jaw plate to form a crushing chamber that is wider at the top and narrower at the bottom. The movable jaw plate performs a periodic reciprocating squeezing motion against the fixed jaw plate, thereby crushing the ore.
The ore is broken down into stone. The moving jaw plate mainly works by the motor operating the connecting rod of the bending structure. Taking the PE-250 jaw crusher as an example, the matching motor power is 300 kilowatts, and the power consumption per unit hour is 300 kilowatt-hours. Calculated at industrial electricity price of 1 yuan per kilowatt-hour, if the crusher runs for 12 hours a day, the electricity cost will be 108,000 yuan per month. However, after installing a frequency converter, the power saving rate is between 20% and 60%. Calculated at 45%, it can save 48,600 yuan in electricity costs per month.
The above only discusses the energy-saving aspects of frequency converters in equipment. More importantly, frequency converters provide better protection for the jaw crusher itself through frequency regulation. When large ore is fed into the operating crushing chamber, the connecting rod of the movable jaw plate generates an initial torque response until the frequency converter receives the signal and reacts by increasing the opening and closing degree of the crushing chamber, thereby protecting the jaw crusher's normal operation and reducing malfunctions.
The stone material from the crusher enters the ball mill. The ball mill has an internal cylinder containing a certain proportion of solid iron balls. As the mill cylinder rotates, the grinding media, due to inertia, centrifugal force, and friction, adhere to the cylinder liner and are carried away by the cylinder. When carried to a certain height, they are thrown back down by gravity, crushing the material inside the cylinder like projectiles. The material is fed evenly into the first chamber of the mill through a spiral feed shaft. This chamber has stepped or corrugated liners and contains steel balls of different sizes. The rotation of the cylinder generates centrifugal force, carrying the steel balls to a certain height before they fall, impacting and grinding the material. After coarse grinding in the first chamber, the material passes through a single-layer partition into the second chamber, which is lined with flat liners and contains steel balls for further grinding. The powdered material is discharged through the discharge grate, completing the grinding process.
It can be said that the power consumption in this process is extremely high. Taking the Zhongkuang ball mill Ф1500×4500 model as an example, if it is run for 12 hours a day and the motor has a power of 110 kilowatts, it will consume 39,600 kilowatt-hours of electricity per month. However, after installing a frequency converter, the frequency converter can control the motor rotation frequency by the size and weight of the stone entering the ball mill. When the amount of stone is not so large, it will reduce the motor speed, thereby reducing the power demand and achieving the purpose of saving electricity. It can save 17,820 yuan per month.
The material ground by the ball mill enters the magnetic separator via a belt conveyor. During the conveyor transport process, the belt conveyor equipped with a frequency converter can effectively adjust the transport speed according to the differences in the transport volume, thereby improving transport efficiency and creating a substantial transport volume. When multiple belt conveyors operate simultaneously, the slave belt conveyor responds according to the frequency converter of the main belt conveyor. The frequency converter also adjusts the speed frequency accordingly based on the individual differences in the weight of each belt, achieving energy saving in this process.
When the stone enters the magnetic separator, taking the WD series magnetic separator as an example, the internal coil of the electromagnetic high-gradient magnetic separator is energized, magnetizing the magnetically conductive stainless steel wool. A highly uneven magnetic field, i.e., a high-gradient magnetization magnetic field, is generated on its surface. Paramagnetic materials, when passing through the steel wool in the separation tank, combine with the applied magnetic field to form a magnetic force, adsorbing onto the surface of the steel wool. Non-magnetic materials pass directly through the magnetic field, through the non-magnetic material valve and pipe, and flow into the non-magnetic product tank. When the weakly magnetic materials captured by the steel wool reach a certain level, feeding is stopped. The excitation power is disconnected, and the magnetic materials are flushed. The magnetic materials then pass through the magnetic material valve and pipe, flowing into the magnetic product tank, and finally forming iron precipitates which enter the finished product silo.
In the process of screening magnetic materials using magnetic separators, frequency converters can be installed. Frequency conversion technology not only achieves the same energy-saving effects as jaw crushers, ball mills, and belt conveyors, but also improves process technology. Through the given control of the frequency converter, the screening efficiency of magnetic materials is increased, and the precision of magnetic stone is also improved, greatly enhancing the "input-output" efficiency. The magnetic iron concentrate flowing out of the magnetic separator will enter the pellet plant for sintering, ultimately producing finished steel. The above describes all the mechanical equipment used in iron ore mining. After installing frequency converters, the energy-saving effect can reach 40-50%, saving 170,000-250,000 yuan in industrial electricity costs per month. Next, I will introduce the application of frequency converters in steel plants; please stay tuned.
In this rapidly developing new era, energy shortages constantly hinder our progress. Therefore, there is an urgent need for new energy-saving products that can help businesses on the input-output line, preventing them from suffering development bottlenecks caused by power shortages. Beijing Xinno Hengcheng Technology Co., Ltd., in recent years, has launched the VFS series of products—general-purpose frequency converters, fan and pump frequency converters, injection molding machine frequency converters, and various special-purpose and customized frequency converters—which are widely used in industries such as steel, petroleum, printing, textiles, coal, cement, chemicals, and animal feed. These products have received widespread recognition and praise from customers in the industry!
