The Variable Conditions Analysis And Energy Efficient Operation Of Fans In The Direct Air Cooling Unit

The energy situation has being becoming more and more critical nowadays. Our energy structure needs to be adjusted; current situation depending too much on fossil energy can no longer meet the requirements of sustainable development of the society. The traditional power generation industry are mainly coal-fired thermal power plant, however, as coal resources are drying up gradually, new energy-based power generation industry is booming, but the dominant position of the thermal power is still difficult to be shaken in the short terms. While the development of the traditional thermal power is limited by the uneven distribution of water resources, that the water resources are rich in the south of China but lack in the north of China, thus limiting the use of water-cooled unit in the North. In order to make full use of the advantage of abundant coal resources in the North, developing air-cooled units will become an irresistible trend. Compared with water-cooled units, the biggest drawback of the air-cooling unit is it’s high exhaust pressure and low power generation efficiency. So it is particularly important to regulate the back pressure of the unit during operation. Viewing from the angle of energy-saving of air fans, this paper analyzed the running characteristics of the air-cooling unit, proceeding from the turbine side, considering a variety of factors, combining the heat balance system diagram in the power plant and Buddha Kruger formula to discuss the change of displacement under different unit load and the change of the power consumed by the fan under different exhaust backpressure. Finally, based on heat balance method, we used Delphi language to programming and calculated the optimal back-pressure of the unit under different turbine load and ambient temperature conditions during operation. Further, Preparing in accordance with the principle of energy-saving operation of the fan, we developed a backpressure optimization software, achieving the goal that under different operating state, by collecting the operating parameters of the unit, gives the optimal fan operating speed. Comparing with the actual operating experience data, indicating that the backpressure optimization software can be used to guide the operation of the power plant, and it has a good sense of reality.