In the thermal power plant, in order to improve the work efficiency and reduce the energy consumption, the high-pressure blower is transformed by frequency conversion.
The original operation mode of the blower is to start with step-down and power frequency operation, and its air volume is adjusted by adjusting the air door. The disadvantages are large waste of electric energy and fuel, poor real-time regulation, high noise and high labor intensity of workers. With the wide range adjustment of power generation load, the air volume of blower is often in a low efficiency state due to the change of boiler load, and a large amount of energy is wasted on the air duct baffle.
In recent years, with the rapid development of high voltage frequency conversion technology, the frequency conversion transformation of boiler drum and induced draft fan has been widely used. Through market research, we have introduced advanced high-voltage inverter to transform the blower as a whole to produce a high-voltage AC system with adjustable frequency and current depending on load, so as to realize continuous speed regulation of three-phase motor.
Energy saving estimation: before the transformation, the current of the blower is about 30a, and the opening of the fan baffle is between 60 ~ 70%. After the transformation, the current of the blower is reduced to 20a, which is reduced by 1 / 3, and the baffle opening is 100%. If the operation condition is based on 24-hour continuous operation and the annual operation time is 300 days, then the annual energy saving is p = 1.732 × 6 × 10 × 0.95 × 24 × 300 = 710812kw · H. According to 0.48 yuan per kilowatt hour, the electricity cost can be saved about 341190 yuan per year.
Other effects produced by the application of high voltage variable frequency speed regulation system: the process has been improved. After the inverter is put into operation, the dust removal fan can adjust the air volume smoothly and stably, and the operating personnel can adjust and control it freely. The operation parameters of the dust removal fan are improved and the efficiency is improved.
Extend the service life of motor and fan. Generally, the dust removal fans are centrifugal fans with long starting time and large starting current (about 6-8 times of rated current), which has great mechanical impact on the motor and fan and seriously affects their service life. After using frequency conversion speed regulation, soft start and soft brake can be realized, which almost has no impact on the motor and can greatly prolong the service life of the machine.
Reduce the wear of valve machinery and fan impeller. After the installation of variable frequency speed regulation, the fan often works at 150 RPM lower than the original fixed speed. Therefore, the wear of the fan impeller is greatly reduced and the fan vibration is reduced. The overhaul period of the fan is prolonged and the maintenance cost and time are saved.
It is convenient to realize the automation of dust control system. The air volume of the dust removal system often needs to change according to the process requirements. In the past, when the damper was used to adjust, there was a linear problem in the relationship curve between the opening of the actuator and the flow rate. Due to the excessive wear of the actuator, the valve characteristics change, and the non-linear problems occur, resulting in the adjustment process error and the automatic control system can not work normally. However, the frequency conversion speed regulation always keeps working in the range of 0.1 ~ 0.01Hz, which creates superior conditions for the automation of dust removal system.
The transformation of the blower not only improves the efficiency of the thermal power plant, but also improves the technology, which brings great benefits to the work of the thermal power plant.