Application Study Of Micron-Scale Droplets Absorbing VOCs Pollutants From Diesel Exhaust

Volatile Organic Compounds(VOCs)are common pollutants in the atmosphere,and their excessive emissions will cause serious harm to the atmosphere and human health.Related source analysis results show that diesel exhaust has become an important source of atmospheric VOCs pollution in China,but the current application of diesel engine VOCs treatment technology has great limitations and it is difficult to meet the increasingly stringent environmental requirements.Therefore,the development of a diesel engine exhaust VOCs treatment device with good effects,low cost,and easy operation is the focus of research in the field of atmospheric pollution control.In this paper,the atomization supergravity technology was applied to treat the diesel engine VOCs pollutants.The generated micron-scale droplets could significantly increase the contact area with the exhaust gas,which was conducive to the gas-liquid mass transfer absorption process,so that VOCs could be absorbed fully by the droplets of the agent to realize the purification treatment of diesel exhaust.Firstly,by measuring the components and contents of diesel exhaust VOCs,the emission characteristics could be quantitatively analyzed to provide a basis for the screening of absorbents.Secondly,the micron-scale atomization effect analysis and VOCs absorption experiment were carried out on several common absorbents to select an absorbent that has the best absorption effect,and further optimized this experiment to obtain the optimal composition ratio of the absorption liquid.Thirdly,by optimizing the four main device parameters of droplet size,atomization volume flow rate of absorption liquid,exhaust residence time,and absorption temperature,a set of operating parameters of the device with the highest VOCs absorption efficiency was determined to realize the cooperative treatment of multi-component VOCs from diesel exhaust.Finally,the benefit analysis of the absorption device was conducted to comprehensively evaluate its application value.The research results show that Through the research of this subject,it was found that:(1)The optimal mass fraction of sodium,citric acid and sodium chloride citrate is: 15%,0.22% and 1%,respectively.The best atomization effect of the absorbent solution and maximum absorption capacity of the multi-component VOCs of diesel exhaust is achieved under this condition.(2)The optimal parameters of the absorption device are: absorption droplet size 5μm,absorption liquid atomization amount 71mL/min,gas residence time after atomization 1s,absorption temperature 20℃.The absorption efficiency of the multi-component VOCs reaches 58.5% under this condition.(3)The result of cost accounting shows that the cost of the absorption device is lower than existing diesel exhaust VOCs treatment technologies.The investment cost of the absorption device is 2880 yuan,and the treatment cost of exhaust from 1L diesel is 1.45 yuan.In general,the micron-scale droplet absorption device designed based on atomization supergravity technology has a good removal effect on multi-component VOCs from diesel exhaust with several advantages of low operating costs,simple operation,no secondary pollution,so it has certain market application prospects.