Reasearch On The Desorption Performance Of Intensifying Basic Aluminum Sulfate Desulfurization Rich Solution By The Jet Flow

At present,there are problems of long desorption time,low desorption rate and desorption rate in the process of thermal desorption of flue gas desulfurization technology by basic aluminum sulfate desorption.In order to solve the above problems,the desorption effect under different jet parameters was studied by using the special effect of jet flow and the multi-mode desorption experimental system,and the macrodesorption performance and its variation rule were obtained.The relationship between the concentration changes of the parameters△_A（△A refers to the difference between the A value calculated at the i+1st sampling point and the A value calculated from the ith sampling point）and SO₃^2-under different working conditions and the time was analyzed,and the optimal combination of jet desorption conditions parameters matching was determined.Combined with the mass transfer theory,the characteristics of desorption mass transfer under different jet parameters were obtained,and the microscopic mechanism of enhanced desorption by jet was revealed.The performance of macroscopic jet desorption shows that jet desorption has positive effects and obvious advantages in shortening desorption time,increasing desorption rate and desorption rate compared with static desorption.High desorption temperature and high mean flow velocity enhanced the desorption performance,with higher section diameter and higher endocorption height,and the desorption rate reached 46.41%and 42.25%at the60min desorption end point,respectively.The average desorption rates were8.12×10^-4mol·L^-1·min^-1and 7.35×10^-4mol·L^-1·min^-1,respectively,which were 7.33%and16.37%higher than static desorption rates at the same temperature.Compared with the average static desorption rate at the same temperature,the static desorption rate increased by 1.89×10^-4mol·L^-1·min^-1and 3.21×10^-4mol·L^-1·min^-1,respectively.At the same desorption time at different desorption temperatures,the relative change rate of jet desorption rate reaches the maximum at 70℃,and the maximum value reaches 71.94%at40min during the desorption process.The relative change rates of desorption rates are the highest at 0.010m,4.00m/s and 0.060m for different section diameters,average flow velocity and endocorption height,and the maximum values are reached at 40min,50min and 40min,respectively.The improvement of jet parameters can make the△_Aat low SO₃^2-concentration level at a higher level,and also improve the fluctuation amplitude of△_Ain the period of gentle trend,in which the desorption temperature has the greatest influence on its variation rule.Finally,the optimal combination of jet desorption parameters under experimental conditions is determined as follows:desorption temperature 80℃,section diameter 0.010m,average flow velocity 4.00m/s,and enrolling height 0.060m.The characteristics of jet desorption mass transfer show that the average volume mass transfer coefficient increases with the increase of desorption temperature.The average volume mass transfer coefficient of jet desorption at 80℃reaches 0.024136 s^-1.In addition,the average volume mass transfer coefficient can be increased by increasing section diameter and average velocity,and the effect of average velocity is more significant than that of section diameter.The entrainment height has relatively little effect on the average volume mass transfer coefficient.When the entrainment height is 0.080m jet desorption,the average volume mass transfer coefficient decreases by 7.54%compared with 0.060m jet desorption.Through the analysis of the response surface regression model of the average volume mass transfer coefficient of jet under 70℃,it is found that the main and secondary order affecting the desorption mass transfer performance under this condition are:average flow rate,section diameter,enrolling height.At the same time,it is found that high entrainment height should be combined with high average flow rate to promote the mass transfer performance of jet desorption process to show better strengthening effect.The important value of jet enhanced desorption lies in that the special effect of jet enhanced the desorption performance of basic aluminum sulfate desulfurization rich solution,which provides a practical and feasible strengthening method for the thermal desorption of SO₂by basic aluminum sulfate.