Research On Water-saving Of Systems Aild Coal Drying At Thermal Power Plant

Although the total amount of water resources is abundant in China, the per capita consumption is low, and the distribution of water resources is extremely uneven on geography. With the rapid development of China’s power industry, the power plant at the area of shortage of water is more and more, the capacity is increasing and the water consumption is also growing. How to effectively use local water resources become challenge face to these power plants.In this paper, to a table type of indirect air-cooled thermal power plant in the northwest of China where is shortage of water as an example. Research and analysis of the plant used, drainage and water balance, the actual water consumption index was calculated and compared with the same index of the direct air-cooled, water cooled and gas turbine units. Analyze the characteristics of water-saving of various types of power plants. Taking the problem of the consuming and drainage of water in the actual operation, find out the potential of water-saving and put forward the profile of water-saving retrofit which involved in industrial wastewater treatment systems, desulfurization systems, domestic water systems and auxiliary cooling water system. Additional, use Visual Basic6.0to write the software to calculate water consumption indexes, provided a convenient for calculating it next.Consider the lignite of characteristics of high moisture, proposed a kind of lignite quality blended systems which creatively use the outlet water of economizer as the drying medium. Compared with the common way of drying lignite by hot flue gas or exhaust steam of turbine, it has advantages in safety and impact on the boiler performance. More importantly, condenser at the end of the System can collect moisture separating from lignite. There is a considerable amount of water can be directly used for the power plant.Design a lignite dryer which is the key of the system, determined its size, load, motor power and conducted stress check by calculating. The heat transfer on the dryer were analyzed to establish a one-dimensional axial overall heat transfer mathematical model about lignite drying and the model was numerical calculated through Matlab. The model predict the temperature profiles of the Coal particle, the gas phase and the Saturated water in drying tube in the axial direction.Taking a power plant1000MW unit in Guangdong as an example, Assume using this lignite quality blended system, then the investment economy of it was analyzed.