Study On Elution Technology Of Tubular Eddy Current Enhanced Petroleum Hydrocarbon Contaminated Soil

Petroleum hydrocarbon,as a kind of soil organic pollutant with large amount,wide range and serious harm,poses a great threat to China's environment.At present,the mechanical method has been widely used due to its advantages of thorough repair,short repair cycle and small secondary pollution.However,the current mechanical method mainly achieves the desorption of pollutants by the method of adding field strength,and has the disadvantage of high energy consumption.The development of a fast and efficient elution technology for petroleum-contaminated soils with lower energy consumption is of great value and significance for the current treatment of petroleum-contaminated sites.In this paper,numerical simulation and experimental test methods were used to study the influence of soil particles on the desorption performance of petroleum hydrocarbon contaminants under different motion patterns,and the optimal structure of vortex generators which enhanced elution by regulating particle motion was determined through experiments.Further,tubular eddy current elution technology was developed by using the optimal structure combined with hydrodynamic cavitation.By studying the effects of different operating conditions on the desorption performance of petroleum hydrocarbon pollutants,a combined repair method for petroleum hydrocarbon contaminated soil was designed.The main conclusions are as follows:(1)The desorption effect of petroleum hydrocarbon pollutants is related to the motion patterns of soil particles.The order of desorption effect was static<linear motion<spiral motion and the desorption effect was further enhanced with the increase of spiral motion winding number;(2)Optimum structure of vortex generator:three blade paths,lead is 12.5 mm,spiral blade adopts different helical blade arranged alternately,between adjacent spiral blade Angle is 90°,number of spiral blade is four;(3)The best operating conditions:tubular eddy current elution cycles for three times,flow velocity of 0.91m/s,the temperature is 80?,solid-liquid ratio is 1:35,the pH value of 7;(4)Comprehensively compare the advantages and disadvantages of tubular eddy current elution technology,stirring elution technology and ultrasonic elution technology,and design a petroleum contaminated soil combination repair method,that is,the particles are broken,the mud is formed by stirring,and then the tubular eddy current elution is passed.The rapid and deep repair of the contaminated soil is carried out by elution,and the soil with high degree of pollution and fine particles is repaired by ultrasound.