Research On Microwave Regeneration Of Fly Ash Used For Waste Lubricating Oil Absorption

Recently,with the rapid development of China's industrial economy,lubricating oil has been used more widely.Then,a large amount of waste lubricating oil has been produced.The waste lubricating oil can be reused by purified or refined.The absorption processing technology takes an important position in the field of waste oil recovery technology.In the application of adsorption process,the selection of adsorption materials are of great concern.As a new adsorbent material,fly ash,which has the advantages of cheap and wide source,can be used for adsorption treatment of waste oil effectively.However,fly ash will lose the adsorption capacity and become a kind of toxic and harmful substances after the adsorption treatment of waste lubricating oil.So,it is necessary to dispose of the waste fly ash.Regeneration methods are effective ways,which can recovery the adsorption capacity of fly ash.The common regeneration methods include thermal regeneration,oxidation regeneration,solvent regeneration,photocatalytic regeneration,electrochemical regeneration,microwave regeneration,ultrasonic regeneration,supercritical fluid regeneration and plasma regeneration.Microwave regeneration is an efficient,rapid and energy-saving method.Domestic and foreign scholars have made much research of microwave regeneration to activated carbon,rather than to fly ash.Based on the microwave regeneration technique of adsorption material,the exploratory study abut microwave regeneration of fly ash used to adsorb waste oil is done in this paper.In this study,the research object is fly ash which used in the adsorption of waste lubricating oil,the regeneration method is microwave,and the evaluation index of regenerated is acid value.Single factor experiment is employed to investigate the effect of microwave power,regeneration time and fly ash particle size to microwave regeneration efficiency.Orthogonal test is used to optimize the experimental conditions.The contrast tests are done between traditional thermal regeneration and microwave regeneration of fly ash used to adsorb simulated waste oil.The contrast tests include the study of the first,the second and the third regeneration efficiency of thermal and microwave and the variation of fly ash surface structure and contact angle.In the end of the paper,the process of fly ash adsorption-microwave regenerated-adsorption is applied to the actual waste lubricating oil.The indexes of moisture content,acid value,viscosity and surface tension are employed to study the adsorption effect of regenerated fly ash used in waste lubricating oil.The regeneration experiment shows that the factors affecting the efficiency of microwave regeneration fly ash are particle size of fly ash,microwave power and regeneration time sequentially.The highest regeneration efficiency can be obtained with the particle size of 0.1-0.2 mm,microwave power of 800 W and regeneration time of 2min.In this condition,the regeneration efficiency is 92.73 %.Thermogravimetric results show that the optimal thermal regeneration temperature is 400 ?.Contrast tests show that the specific surface area,total pore volume and average pore size of fly ash decrease gradually after regenerated by microwave in three times.And fly ash is more in crystal state.In contrast,the specific surface area and total pore volume of fly ash increase gradually after regenerated by thermal in three times.And fly ash that in crystal state decrease.Under the condition of having the same regeneration efficiency,the energy consumption of microwave is lower when compared with thermal regeneration,which only accounts for 1/66~1/36.The contact angle experiment shows that if the frequency of microwave regeneration increases,the affinity of liquid paraffin to fly ash,the relative contact angle increases,and the surface free enthalpy of fly ash are all decrease.The last experiment shows that moisture content,acid value,viscosity and surface tension of waste lubricating oil can be reduced by the adsorption of fly ash.However,the reduction will be lower when the frequency of microwave regeneration is more.