Abstract: This article describes the application of high-voltage frequency converters in Shandong Sun Paper Industry Co., Ltd. Chemical Vaporization Blower Pump. Through the introduction of the frequency conversion reform plan for the fan pump and the comparative analysis of the energy-saving effect after the transformation, it is shown that the energy-saving effect of the frequency conversion reform of the fan pump in the paper mill is significant, and it has high economic benefits.
Keywords: high-voltage frequency converter fan pump energy saving
Abstract: This paper introduces the high voltage inverter in Shandong Sun paper company limited pulp application of evaporating fan pump. Through fan pump frequency conversion reconstruction programme after the introduction and improvement of energy-saving effect of a comparative analysis, it is remarkable that paper mill Fan pump energy saving effect of frequency conversion transformation, has high economic efficiency.
Key words: High voltage inverter Fan pump Energy-saving
1 Introduction Shandong Sun Paper Co., Ltd. is a global advanced multinational papermaking group and forestry pulp and paper integration company. It is the largest private papermaking company in China, the largest high-grade coated packaging board manufacturer in China, and China's food grade packaging paper. Leading company. The group has total assets of RMB 18.6 billion and annual pulp and paper production capacity of 3.5 million tons. The products mainly serve China, the United States, Africa, Southeast Asia, and other countries and regions.
Creating a resource-conserving and environment-friendly enterprise and pursuing harmony, unity, and mutual benefit between the enterprise, the environment, and society are the unremitting efforts of the Sun. With the continuous intensification of the market economy, energy conservation and consumption reduction have become one of the effective means for the company to reduce production costs, increase profit margins, and enhance the competitiveness of the company.
2 transformation project introduction
The process flow of chemical black liquor evaporation system is: the black liquor produced by pulping is discharged into the waste liquid tower through the pressure sieve filtration, enters the evaporator through the waste liquid tower, and undergoes evaporation classification treatment through the evaporator, in which the heavy pollution concentrate Discharge into the concentrate pool and enter the alkali recovery process. The light pollution is discharged into the wood chip washing tank to clean the wood chips. The evaporated white water enters the white water tower and the disc mill dilution water, and is discharged into the hot white water tank and recycled into the chemical pulp slurry system. To achieve zero discharge of waste water.
The MVR evaporation technology used for black liquor evaporation represents the highest level of global wastewater evaporation treatment. The principle is to use an evaporator blower pump to process the secondary steam generated by evaporation, convert the electrical energy into heat energy, increase the enthalpy of the secondary steam, and use the secondary steam of the increased heat as a heat source to drive into the evaporator to heat the black liquor to achieve The existing heat energy of the secondary steam is recycled, no external fresh steam is needed, and the purpose of evaporation and condensation is achieved by relying on the evaporator to recycle.
Evaporative fan pump It is the core component of the black liquor evaporation system. Its reliable and stable operation is the fundamental guarantee for the normal operation of the whole black liquor evaporation system. Due to the special function of the evaporating fan pump in the whole system, it is a special type of load, neither fan nor equivalent to ordinary pump load. Evaporation blower pump power is high energy-consuming equipment in chemical vaporizer evaporation section. If it can successfully carry out energy-saving transformation, it will produce very considerable benefits.
Evaporative fan pump supporting high-voltage motor parameters are shown in Table 1.
During normal operation, the baffle opening of the fan pump outlet must be adjusted to meet the process requirements. The baffle opening is usually between 50% and 60%, and the motor is always running at full speed. Due to the baffle adjustment, the baffle causes a great energy waste, and the smaller the baffle opening, the more energy is consumed, and the higher the power consumption of the high-voltage and high-power motor.
The project aims to transform the fan motor by frequency conversion, and to increase the efficiency of the motor drive system by adjusting the speed of the motor. When the frequency conversion is adjusted, the baffle can be fully opened to avoid losses caused by the baffle adjustment.
With the increasing maturity of domestic high-voltage high-power frequency control technology, this technology is widely used in various industries, and more and more applications of domestic 10kV voltage class inverters have been verified: ABB, VACON, Rockwell and other well-known Foreign brands do not have this level of 10kV. They adopt an alternative approach to solve the problem. They need to increase their voltage transformers or replace the matching motors. Considering the current domestic technology of such products is also relatively mature, the key components are also selected from abroad. , And in the price, after-sales service and technical support and other aspects have more advantages, after a lot of research and comparison, we finally chose the Shandong New Scenery Electronic Technology Development Co., Ltd. JD-BP38-3000F type (3000kW/10kV) high-voltage inverter Device. Table 2 shows the main parameters of the JD-BP-3000F high-voltage inverter.
3 transformation program before the transformation, the original system 10kV high voltage switch cabinet to the motor, motor and fan pump directly connected, after the transformation, the system 10kV high voltage switch cabinet to high voltage inverter, high voltage inverter connected to the motor, do not need to do between the motor and fan pump Any changes.
In order to prevent the impact of frequency converter inspection or failure on production, the JD-BP38-3000F high-voltage frequency converter adopted this time is equipped with a manual power frequency bypass and adopts a one-to-one control method. The device is wired once as shown in Figure 1:
Figure 1 Manual bypass cabinet primary circuit
In the manual bypass cabinet, there are three high-voltage isolation switches K1, K2 and K3. When K1 and K2 are closed and K3 is disconnected, the 10kV power supply is passed through the isolation knife K1 to the high-voltage inverter, and the inverter output is sent to the motor via K2. The motor runs in variable frequency; once the frequency converter fails, the isolating switches K1 and K2 can be disconnected, K3 can be closed, and the motor can be started under the commercial frequency power supply. At this time, the inverter is isolated from the high pressure, which is convenient for maintenance, maintenance and commissioning. The isolation barrier K1, K2, and K3 have a lock-up and misoperation prevention function.
Utilizing the reservation points of the original DCS control system, the high-voltage variable frequency speed control system was incorporated into the original DCS control system, achieving remote/in-place control functions. In the local monitoring mode, the local inverter can manually start and stop the inverter through the touch screen display on the inverter, and the speed and frequency can be adjusted; the local control window adopts the Chinese operation interface, and the function setting and parameter setting are all In Chinese; In the remote monitoring mode, remote manual start and stop of the inverter can be performed through the peripheral terminals of the inverter, and the speed, frequency, and operation frequency and output current can be monitored. When the high-voltage variable-frequency speed control system fails, the system sends the fault information to the DCS to facilitate the timely troubleshooting.
The high-voltage variable frequency speed control system and the upper-level switch cabinet are set to be interlocked. When the upper-level switch cabinet breaker is in the closing position, the high-voltage isolation switch in the bypass cabinet of the variable frequency speed control system must not be operated to prevent arcing. To ensure the safety of operation, when a serious fault occurs, the upper-level switchgear circuit breaker protection high-voltage variable frequency speed control system and the motor can be promptly opened.
4 Frequency conversion after the operation of the effect
4.1 Energy Saving Effect After the frequency conversion of the evaporator blower pump, the high-voltage inverter was successfully put into operation once. The transformation achieved the intended purpose. The site running photo is shown in Figure 2.
Compared with the original power frequency driving method, the baffle is fully open, the frequency conversion speed control system operates at about 45 Hz, and the power consumption when adjusting the baffle is greatly reduced. Table 3 shows the operation data before the frequency conversion. Table 4 shows the operation data before the frequency conversion. Table 5 shows the comparison table of the motor operation data before and after the frequency conversion.
According to the data record, the reduced input power after frequency conversion is put into operation is: 493kW, and the energy saving rate is 24%. According to the average daily operation for 24 hours, 330 days in a year, the electricity price is calculated at 0.65 yuan/kWh.
Annual electricity: 493*24*330=390.456 (million kW?h)
Annual electricity savings: 390.456*0.65=253.8 (ten thousand yuan)
Each kilowatt-hour saved is equivalent to saving 0.404 kilograms of coal energy consumption and 4 liters of pure water, while also reducing 0.96 kilograms of carbon dioxide and 0.03 kilograms of sulfur dioxide emissions.
After the energy-saving transformation, the annual energy saving equivalent to saving 1577 tons of coal energy consumption and 15.62 million liters of purified water, reducing 3748 tons of carbon dioxide and 117 tons of sulfur dioxide emissions.
4.2 Indirect benefits (1) Through the frequency conversion and energy saving transformation of key energy-consuming equipment, the company's power supply pressure can be well relieved.
(2) The labor intensity of on-site operators is greatly reduced. After the frequency conversion transformation, the remote control of the fan pump can be realized. According to the amount of the black liquor entering the evaporator, the motor speed can be adjusted at any time to meet the production needs, without artificially going to the scene to adjust the baffle. The adjustment of the blower pump is more precise and the frequency conversion adjustment is more intuitive than the damper adjustment, and it is welcomed by field operators.
(3) The on-site operating environment has been effectively improved. Since the motor and the load speed have decreased, the noise pollution of the equipment has been greatly reduced and on-site operators are very welcome.
(4) Extended motor and fan pump life. After frequency conversion, most of the fan pump's operating time runs at a lower speed, which greatly reduces the mechanical strength and wear of the fan pump, which will greatly extend the service life of the fan pump and the motor.
(5) Reduced the impact on the power grid. After adopting frequency conversion regulation, the system achieves soft start, the motor starting current is much smaller than the rated current, and the start-up time is prolonged accordingly. There is no big impact on the power grid and the startup is smoother.
5 Conclusion Scenery JD-BP38-3000F high-voltage inverter on-site operation shows that the use of domestic high-voltage inverter for chemical machine evaporative fan pumps and other key energy-consuming equipment for speed and energy saving, can effectively reduce the production cost of pulp, so that the company The increasingly competitive market is more competitive. The frequency conversion reform of the paper mill's CMP evaporator blower pump is a breakthrough for high-voltage inverters in the papermaking field, which has great potential for promotion in the industry.
references
[1]Shandong New Scenery Electronic Manual [Z]. Shandong New Scenery Electronic Technology Development Co., Ltd.
[2] Xu Yurong. Application practice of high-voltage frequency conversion speed regulation technology. Beijing. China Electric Power Press.
Author brief introduction Song Fuchen male, engineer, worked at the electrical instrument department of Shandong Sun Paper Co., Ltd.