Study On Fluid Transients In Water Cooling System And Cold End Parameters Optimization Of Thermal Power Plants.

With the dramatic economy growing of China in recent decades, the power generation industry developed rapidly to fill up the power shortage gap. Thermal power has been retaining the portion of 63 % or so in the whole generation capacity of the world. The thermal-power unit is now developing in the direction of super-high parameters, big capacity, high efficiency and large-scale power plants. It makes the designing of cooling system at power plant more and more complex, so the reliability and safety of system operation are being paid great attention within the industry. Meanwhile, as the extension of generation capacity at power plant and consumption of un-renewable resource in the world, the impact of the optimal design and operation in the water supply system on the unit economy nowadays has been the focus research of energy conservation.Based on the existing literature, the comprehensive and in-depth research, which focused on the advancement of the safety during transient process in water cooling system and the operation economy and stability of cold end at power plant, was carried out in this paper.1. Mathematical model of fluid transient analysis in the cooling system was built and different types of system boundary condition were analyzed. Based on that, the program was made and then validated by the comparison between the simulation results with the project testing data. By the transient simulation of a specific power plant, some measures were raised to control the system water hammer.2. The selection of construction parameters for siphon-well in one-time flow cooling system was discussed, and some suggestions were given based on the simulation of a project example. Furthermore, the mathematical model for another special type of siphon-well (with air-check) was developed, and its basic structure and application principle were introduced.3. The method of hydraulic transient simulation combined with condenser off-design calculation was raised in this paper to seek for the optimal valve movement law, which could correct the deficiencies of neglecting the dynamic character of condenser while cooling water quantity changed during transient process.4. The mathematical model of optimal operation mode in cooling system was built, and the calculation of optimal operating was made for both water supply systems: (1) the water quantity could be adjusted continuously; (2) the water quantity could not be adjusted continuously.5. The thermal performance theory and economic analysis of the dual-pressure condenser were explained. By the calculation for a real project the economical efficiency of single-pressure and dual-pressure condenser were compared, which indicated that the dual-pressure condenser was economical especially for high-capacity generation units.6. Designing optimization of the cold end system at power plant was analyzed, and the mathematical model was developed. Combining with 600MW unit optimization example, some hypersensitive issues were compared and analyzed by using the correlative optimizing program, which has significant meaning to improve the economy of cold end .