Thermo-hydraulic Performance Analysis And Optimization Study Of Indirect Dry Cooling System Incorporate Desulfurization Tower And Chimney

Indirect dry cooling tower of three incorporate towers system refers to a system optimization arrangement technology which arranges desulfurization absorption tower and chimney in the dry cooling tower. This new technology has both the functions of energy saving, water saving and environmental protection, which has been developed rapidly recently. In this paper, on basis of the 660MW large-scale indirect dry cooling system of three incorporate towers units in a thermal power plant, the thermal-flow performance under different arrangements of the three incorporate towers has been studied. Meanwhile the effect of ambient temperature and ambient wind speed on the thermal-hydraulic performance of units has been researched.According to the size of dry cooling tower, desulfurization tower and chimney, also considering the flow of exhaust gas, design a proper eccentric distance of desulfurization tower and chimney in the dry cooling tower. And establish physical models of dry cooling system under different arrangements. CFD numerical simulation is used to study the effects of ambient wind on thermal-flow performance of indirect air cooling system under different eccentric arrangements. The results show:on no wind condition, eccentric arrangements has no effect on the thermal-hydraulic performance of system, but eccentric arrangements is harmful to the spread of exhaust gas; Under ambient wind condition, when desulfurization tower, chimney arrange along the upstream direction, the performance of system changes a little. When desulfurization tower, chimney arrange along the downstream direction, the larger eccentric distance is, the worse the performance will be. When desulfurization tower, chimney arrange perpendicular to the wind direction, a significant deterioration of the performance occurs only at 8m/s wind speed. In general, eccentric arrangement of desulfurization tower and chimney are adverse to the thermal-hydraulic performance of system. It is also bad for gas diffusion and cooling tower wall corrosion prevention. So in practical applications, it is recommended to arrange the desulfurization tower and chimney at the center of dry cooling tower. If eccentric arrangement is required, upstream direction is suggested under the premise of a good wall corrosion prevention.By establishing an iterative algorithm which couples turbine exhaust, circulating water and air, thermodynamic calculation and numerical simulation methods are used to achieve the flow filed of dry cooling tower, back pressure of turbine, the inlet and outlet temperature of circulating cooling water as well as the heat rejection. And the variation of these parameters under different environment conditions has been studied. At different ambient temperatures, the trend of back pressure vary with wind speed is different, the higher ambient temperature is, the more sensitive back pressure is to ambient wind speed. Meanwhile high back pressure conditions has been analyzed with concrete data. At different ambient temperatures, it has the same law of the thermal-hydraulic performance of dry-cooling tower vary with wind speed. And the heat rejection, the inlet and outlet water temperature are linear with ambient temperature.