Application of FGI frequency inverter in sewage treatment
1. Overview
For the dyeing and finishing industry, power consumption is the main part of its production cost, and the dyeing cylinder is one of the main energy consumption equipment for dyeing yarn;
With the development of frequency conversion control technology, frequency conversion control of flow pressure has been widely used in the dyeing and finishing industry. The energy-saving transformation of the dyeing cylinder has also become an effective way to reduce the energy consumption cost of the dyeing yarn and improve the competitiveness of the product. Therefore, the application of AC frequency conversion speed control device in the dyeing cylinder is of great significance to reduce energy waste. The dyeing process is a predetermined periodic action process, that is, the time control of influx and outflow to achieve the dyeing process. The inner outflow is mainly realized by commutator; the flow of yarn is mainly realized by the main pump.
The first one is the hardware loss. The main pump of ordinary dyeing cylinder adopts the original Y- △ step-down start, whose starting torque and starting current are large, which accelerates the aging of the main pump and the accelerated wear of the commutator. Increased maintenance costs and energy waste.
The second is the overflow loss. With the different processing process of yarn, the temperature, flow rate and pressure required by each process are different. For the main pump motor, the load of the dyeing cylinder in the dyeing process is in a changing state. The flow of the pump is designed according to the required maximum flow, and the original main pump motor provides the pressure flow at constant speed, when the flow required by each pump yarn is less than the maximum flow, the color flows through each pound of yarn, so that it is not color in a short time, this part of energy is lost.
The third is the throttle loss. When the water flow through the reversing mouth of the commutator, there will be a certain flow and pressure, increasing the torque of the reversing solenoid valve. At the same time, due to the long-term full speed circulation of water and the mechanical violent friction of the commutator, the sealing ring temperature is too high, the commutator noise is too large, mechanical life shortening and other bad phenomena.
The fourth is the design allowance loss. Usually in the design, the sharing is generally taken into account, and the design is based on the maximum capacity, so the design capacity of the main pump motor of the dyeing cylinder is much higher than the actual need, there is the phenomenon of "big horse pull small car", resulting in a lot of waste of electric energy.
2. Implementation plans
According to the process requirements of dyeing yarn, the original main cylinder injection pipe is changed into flow controller into 4-20 mA current signal. PLC of FD 300 is linear with the analog signal of the flow controller. After the PLC, the pressure and flow rate will automatically adjust the motor speed to reduce the output power of the motor, and the reversing switch is installed at the reversing solenoid valve, ensuring that the reversing solenoid valve is fully operated. When the internal and external flow change, the speed will be automatically reduced according to the switching switch action, and automatically accelerate to the required frequency after the change is completed, so that the energy loss of the motor and the reversing valve in the whole load range can reach a small degree.
3. Application advantage
3.1 Cost reduction, easy to operate.
The original water level controller and magnet signal of the main cylinder are removed to the analog signal controller to control the water level. And add a man-machine interface to view the real-time water level of the main cylinder. The main cylinder has been exempted from water operation resulting by the accident. Remove the water level controller of the material cylinder, and realize the water level control with the original analog signal controller to reduce the maintenance cost and production cost.
3.2 Increase the power factor and save energy.
Reactive power not only increases the line loss and the heating of the equipment, but also mainly because the decrease of the power factor leads to the decrease of the active power of the power grid. Well, when the power factor, the greater the active power. The COS φ value of the ordinary main pump is between 0.6-0.8, but after using the frequency conversion speed control device, due to the compensation effect of the filter capacitor in the FD 300 frequency converter, COS φ 1, thus reducing the reactive power loss and increasing the active power of the power grid.
3.3 Soft start energy saving.
Because the original motor is directly started or Y / △ started, the starting current is equal to (3-7) times the rated current, which will cause serious impact on the mechanical and electrical equipment and the power supply grid, and will also increase the capacity requirements of the power grid, the large current and vibration generated by the start are extremely unfavorable to the service life of the equipment. After the use of frequency conversion energy saving device, the use of FD 300 inverter soft start function will start current from zero, the maximum is limited in the inverter set in the acceleration current limit level, generally not more than 1.2 times the rated current, reduce the impact on the power grid and the requirements of power grid capacity, prolong the service life of the equipment.
