The Shanghai Laogang Renewable Energy Utilization Center incinerates 3,000 tons of municipal solid waste per day. It is equipped with an advanced flue gas treatment system and power generation facilities. It is one of the largest municipal solid waste treatment facilities in Asia and also one of the facilities with the highest environmental protection requirements. The project started construction in August 2010 and was completed and put into trial operation in May 2013. After the project is put into operation, it will be able to process 1 million tons of domestic waste annually, generate approximately 250 million kilowatt-hours of electricity annually, and provide about 200 million kilowatt-hours of electricity to the grid annually. The slag after garbage incineration will be comprehensively reused, such as as landfill cover materials, brick-making, and roadbed paving, etc.
This project uses 13 sets of Sinotimes FGI FD5000S series medium voltage drive, including 4 primary fans, 6 feed water pumps and 3 circulating water pumps. This article takes this project as an example to introduce the application characteristics of the FGI FD5000S high-voltage frequency converter in fans and pumps in the power industry, and explains the on-site application process, technical characteristics of the frequency converter and application effects.
1.On-site application process introduction
In the circulating water pump system, the circulating water pump realizes the recycling of water resources. The hot water at the outlet of the condenser enters the cooling tower. After the heat of the circulating water is transferred to the atmosphere and the temperature drops, it is lifted by the circulating water pump to be pressurized and then enters the condenser for cooling and low-pressure cylinder exhaust. Since the water level in the system is basically stable, the head of the circulating water pump is also basically stable. That is to say, the volume of water in the circulating water pump determines its power consumption.
Due to the changes in the unit load and the external environment, the vacuum is constantly changing. Therefore, it is necessary to adjust the circulating water volume in a timely manner to ensure the safe and economic operation of the unit. During normal operation in winter, the low-speed operation of one circulating water pump is sufficient to meet the cooling requirements of the unit. However, in seasons with large temperature differences and when the load varies greatly, although the circulating water pump adopts high and low dual-speed regulation methods, it cannot ensure that the unit operates in an economical manner, resulting in a high factory electricity consumption rate and high power generation costs. Therefore, it is necessary to carry out frequency conversion regulation on the water pump.
By using a high-voltage frequency converter to adjust the speed of the circulating water pump motor according to actual needs, the amount of cooling water from the water pump can be regulated. This not only reduces the power of the motor but also achieves the most favorable vacuum control purpose. Thus, it not only ensures and improves the operating conditions of the generator set but also achieves the effect of energy conservation and consumption reduction.
In order to reduce the electricity consumption rate of the factory and lower the power generation cost, the Shanghai Laogang Renewable Energy Utilization Center has decided to install the FGI FD5000s series high-voltage frequency converter on one circulating water pump in the power plant to achieve an economically efficient operation mode.
2.Technical features of FD5000S Medium Volatge Drive
The ideal power of machinery: The high-order harmonic components contained in the output current are extremely small, and the resulting pulsating torque has negligible influence on the shaft system, reducing the vibration of the motor. Selection of curve function: due to mechanical mixer is a multi-stage transmission mechanism, different machine have different features, offers a variety of curve algorithm to adapt to the different mechanical process requirement. High voltage frequency conversion must meet the requirements of field water pump load and dynamic response to the needs of the fast brake operation.
3. Application effect Analysis
Save energy. Compared with the traditionally controlled fans and pumps, the fans and pumps controlled by frequency converters have the most practical significance in energy conservation. Adjusting the rotational speed of the fans and pumps according to the on-site raw material demand is an economical operating state.
The operating cost has been reduced. The operating costs of traditional fans and pumps consist of three parts: procurement cost, maintenance cost and energy cost. Among them, energy costs account for approximately 60% of the operating costs of fans and pumps. By reducing energy costs and minimizing the impact on equipment after variable frequency starting, maintenance and repair volumes also decrease accordingly. Therefore, operating costs will be significantly reduced.
