Structure Optimization And Water-saving In Counterflow Wet Cooling Tower

The natural draft wet cooling tower is widely used in power station for cooling the circulating water, the cooling performance would directly affects the cycle thermal efficiency and economic benefit of the unit. Taking the 300 MW unit as an example, the tower water temperature decrease 1℃, the vacuum of the unit can improve 400 Pa ~ 500 Pa and the coal consumption of the power generation standard decrease 1.0g/(kW · h) to 1.5g/(kW · h).With the development of power industry, power unit appears continuously, the cooling tower performance requirements are also increasing. It has important value of engineering application by studying deeply of the cooling performance of the cooling tower and further tapping the potential of the cooling tower.This paper established a 1000 MW natural rheumatism type cooling tower of three-dimensional numerical calculation model by using FLUENT software. it simulates the internal air flow field and gas-water heat exchange. It verifies the accuracy of the mode by comparing with the measured data.The filler layer region is the most important heat exchange part of the natural ventilation cooling tower, accounted for 60%-70% of the total heat transfer of the cooling tower. It puts forward the idea of using arc filler instead of the traditional horizontal packing layer by the study of packing layer arrangement. Based on the fluent simulation software, established a wet cooling tower heat and mass transfer model. It studies the influence of different radian layer packing arrangement of the cooling tower and analyses the impact of different natural crosswind conditions, relevant parameters such as air flow field and water temperature. The simulation results show that, arc-shaped fill improved the air flow field, compared with the traditional horizontal layout,increases the packing layer heat transfer area in a certain extent,increases the heat transfer, increases the cooling tower pumping power and reduces the outlet water temperature. Under the cross wind, it Can effectively reduce the damage to the internal flow field in the cooling tower and this improvement is more significant. The outlet water temperature can reduce 0.36 ℃.The study shows that the cooling performance difference is big along the radial direction in different areas of the packing layer. In the central area of air cooling tower, air temperature is high, the heat exchange efficiency is low, The external region, the air temperature is low, so the heat exchange efficiency is high. In order to maximize cooling performance of the cooling tower, it should increase the thickness of outer packing layer and the leaching water density, accordingly reduce the central region to drench water density. Water should be distribution and partition for the inside and outside the area. This paper studied on the basis of the packing layer thickness, the different internal and external partitioning scheme, emphatically simulated from the direction of the water spray density, it provides a certain reference for the design of cooling tower in- outer partition and water distribution scheme.For the great loss of evaporation water in cooling tower, this paper analyses several different water-saving methods. It descriptions of the possibility of atomization cooling tower water saving technology and implementation details. This 1000 MW unit cooling tower, for example, calculates the cooling tower water losses and estimate the required condensing agent traffic.