Application of CFV9000A high-voltage AC Drive in chemical plant

Why use Variable Frequency Drives (VFD) in Chemical Production?

Most chemical enterprises use high-voltage motors to drive fans, pumps and other transmission equipment at a constant speed, and use the method of adjusting the damper or valve to adjust the air volume or flow, so as to achieve process production requirements. Although this configuration can meet the needs of the production process, it has the following serious deficiencies in actual production:

(1) The throttling adjustment method wastes electric energy.

In the design, the rated capacity of fans and water pumps usually selected is often larger than the actual demand of the production process, so that the rated capacity of the supporting motor is larger. Therefore, the damper or valve has to be closed for throttling adjustment during actual operation.

During the throttling process, the characteristic curve of the fan or water pump remains unchanged, and the rotational speed remains unchanged, and the flow rate is reduced by artificially increasing the resistance of the pipeline by closing the damper or valve. The opening of the damper or valve decreases, and the resistance loss increases accordingly, but the input power of the system does not decrease much, and the input power is lost in the process of throttling.

(2) The air volume or flow rate is adjusted by the damper or valve, the pipeline resistance loss is large, the throttling power loss is large, and the energy consumption is wasted. The fan or water pump (oil pump) and motor vibrate greatly, the impeller wears seriously, the equipment is easily damaged, and the maintenance cost is high.

(3) The high voltage of the motor starts directly, and the starting current is large, which increases the burden on the power grid, and at the same time has a great impact on the motor and the driving mechanical mechanism, which increases the capacity of the power grid and the damage and maintenance of the motor and mechanical mechanism.

(4) The system stability and control accuracy of throttling adjustment are poor. Due to the nonlinear relationship between the baffle opening of the damper or valve and the flow, and the influence of the mechanical transmission gap of the actuator, the adjustment of the baffle opening is neither sensitive nor accurate, and it is impossible to achieve rapid and accurate adjustment of the flow.

The variable speed drive has excellent speed regulation function and remarkable energy saving effect. Its application improves the speed regulation performance of chemical machinery and its stability in chemical production lines, and has become an ideal choice for chemical enterprises to adjust and control equipment.

Application Case of CFV9000A high-voltage AC Drive

Relying on abundant phosphate rock resources, a chemical enterprise has a raw ore production capacity of 12 million tons per year, and has several large-scale phosphorus chemical and by-product production facilities. In order to improve the operating efficiency and economic benefit of the equipment, high-voltage ac frequency inverters are used to transform the existing equipment drive control system.

The main purpose of CFV9000A high-voltage AC Drive is to realize stepless speed regulation of AC motors. Based on the two/four-quadrant synchronous (including permanent magnet synchronous motor)/asynchronous motor platform design and unit sealing design, the whole machine adopts the modular design idea, which has high production efficiency, low harmonics, precise speed regulation, and strong environmental adaptability.

Installing frequency inverters in chemical enterprises can not only ensure the stability and safety of production systems, but also have significant energy-saving effects.

XICHIELECTRIC High-voltage Variable Frequency Drive Cabinet 

Advantages of Applying Adjustable Frequency Drive

✔ The energy saving effect is obvious. The frequency conversion speed regulation technology is reliable and can be widely used in asynchronous  motors such as fans, water pumps, acid pumps, and oil pumps in chemical enterprises. The general power saving is more than 25%.

✔ At low load, the fan or water pump (oil pump) runs at low speed, and at the same time, the adjustment link of the damper or valve is reduced, so the noise is greatly reduced and the on-site environment is improved.

✔ Basically cancel the damper, valve or hydraulic coupling adjustment, avoid the wear of the damper or valve and its actuator, and also reduce the maintenance cost and equipment downtime rate.

✔ It can effectively realize the soft start of the motor, avoid the impact of the direct start of the motor on the power grid, motor, fan and other equipment, prolong the service life of the equipment, and reduce the failure rate of the equipment.

✔ Improve the power factor so that the system power factor can reach more than 0.95, which can realize the local compensation of the motor, reduce the reactive power loss between the power supply and the motor circuit, reduce the harmonic pollution to the power grid, and improve the quality of the internal power grid of the enterprise.

✔ It is easy to realize automatic control of production process and perfect protection function.

✔ While saving electricity bills, it also saves standard coal consumption for the country, and reduces SO₂ and CO₂ emissions, resulting in significant social benefits.

Precautions for using Variable Speed Drive

a. When selecting a frequency inverter, the process requirements must be met. In a specific environment, the pump is limited by the lift and flow, and the variable frequency may not be applicable. VFDs are not suitable for pumps with high loads and infrequent changes in operating conditions. 

b. The power of the variable frequency drive matched with the motor should generally be equal to or higher than that of the motor, and the type selection should select the frequency inverter with a higher level, which can be matched with the device and instrument and can implement closed-loop control.

c. When adjusting the speed of the VFD, professionals engaged in equipment, instrumentation, technology, and electrical must cooperate with each other, so as to ensure that the frequency drive runs under safe conditions.

d. The relevant personnel engaged in the installation of ac drives must undergo strict professional training.

To sum up, the variable frequency drive has achieved remarkable power-saving effect when used in the drive control of fans and pumps. It is an ideal speed control method. It not only improves the equipment efficiency, but also meets the production process requirements, and greatly reduces the equipment maintenance and repair costs, and also reduces the shutdown period. Its economic benefits are very obvious.