| In order to solve the current situation of China’s lack of freshwater resources, desalination industry is flourishing, such as reverse osmosis and distillation technology (multi-stage flash and low temperature multiple effect distillation) have made considerable progress. Seawater into freshwater has realized industrialization, but the concentrated seawater with an equal amount of freshwater has become a by-product, whose concentration is one times higher than seawater. By combining desalination plant with the natural evaporation of salt, not only solves the problem of concentrated seawater discharging, but also allows resources to be fully rational used, has great significance for the desalination industry chain.This paper study on the natural evaporation law of concentrated seawater, proved the effect of meteorological factors (solar irradiance, environmental temperature, relative humidity and wind, etc.) and the brine conditions (brine concentration and brine temperature) through the indoor natural evaporation simulation experiment system.(1) Reveals the single factor’s mechanism and law on the concentrated seawater natural evaporation. On the one hand, concentrated seawater evaporation rate increases with irradiation, wind speed, humidity, in the form of a linear function. Under the certain condition of meteorological and brine, irradiation intensity increase per 0.1 kW, evaporation rate increase about 0.026mm/h; wind speed increases per 1m/s, the evaporation rate increased 0.016mm/h; and the relative humidity increase per 10%, evaporation rate reduce 0.06 mm/h. On the other hand, the evaporation rate increases with the brine temperature, ambient temperature, in the form of a quadratic function.(2) Through the response surface method studied and proved the two factors synergy mechanism and law on the concentrated seawater natural evaporation. The combination of a moisture evaporation controlling factor (irradiation, environmental temperature and brine temperature) and a moisture diffusion controlling factor (wind speed, relative humidity and brine concentration) can produce significant synergies of concentrated seawater natural evaporation rate, Such as irradiation and wind speed, irradiation and humidity, brine temperature and wind speed, brine temperature and relative humidity, brine temperature and brine concentration. Two factors combined control of vaporization the moisture, the impact on the rate of evaporation mainly as a factor which linear law. When the combination of two moisture evaporation controlling factors, the evaporation rate is mainly varies with one factor in the linear. When the combination of two moisture diffusion controlling factors, the evaporation rate is mainly varies with one factor in the form of a quadratic function.(3) Using principal component analysis method studied the multi-factor synergism mechanism and law on the concentrated seawater natural evaporation. Using the principal component analysis of statistics extract three main components:The first principal component (F1) is a comprehensive index of vaporization, mainly including brine temperature, environmental temperature and irradiation, F1=(0.429 irradiation-0.248 wind speed+0.354 relative humidity+0.914 brine temperature+0.881 environmental temperature-0.026 brine concentration)/(?); the second principal component (F2) is the comprehensive index of diffusion, mainly including wind speed and brine concentration; F2=(0.151 irradiation+0.822 wind speed+0.118 relative humidity-0.005 brine temperature+1.141 environmental temperature +0.846 brine concentration)/(?); The third principal component (F3) is the humidity index, F3=(-0.774 irradiation-0.129 wind speed+0.796 relative humidity -0.019 brine temperature +0.045 brine temperature+0.145 brine concentration)/(?). Multiple linear regression analysis was carried out on the three principal components, and the regression equation is obtained: Y=126.819+5.919F1+12.935F2-9.098F3 (R2-adj=0.777**). With 5% sample data to test the regression equation, the standard deviation is 11.8%, less than the regression equation directly by the original data 16.7%(R2-adj= 0.581**). |
