Study On Performance Of Methanol Emulsified Diesel Oil Prepared By Ultrasonic

The environmental pollution and oil imports continuing to increase are two major currently facing problems in our country.The fuel mixed with oxygen fuel as an alternative fuel,which can effectively reduce SO2,NOX and soot emissions,and in line with the requirements of saving energy and reducing environmental pollution.Methanol has a series of unique advantage,which is rich in resources,affordable,easy to prepare and good physical and chemical properties of alternative fuels.However,the polarity of methanol and diesel is different,which makes it hard for them to mix.And even if the diesel oil is emulsified,it also has poor stability and little addition of methanol,which limit its application.The use of emulsifier combined with emulsifying equipment to prepare methanol emulsified diesel oil can solve this problem.The ultrasound transmits as a series of compression(positive pressure)and rarefaction cycles(negative pressure)affecting the molecules in the liquid.The implosion of the bubbles generates localized high temperature and high pressure microenvironment,Which can strengthen the mixing efficiency.The emulsion prepared by ultrasonic equipment can reach the level of micrometer and has the advantages of uniform dispersion,good stability and sufficient combustion and so on.In this paper,the high-speed disperser was used for pre-emulsification and ultrasonic equipment was used for depth emulsification.The effects of methanol content,emulsifier content,ultrasonic action time and ultrasonic power on the stability and dispersibility of methanol emulsified diesel oil were studied to find the best operating conditions.And then the effects of various factors on the rheological properties,physical and chemical properties of methanol emulsified diesel oil were studied,the methanol emulsified diesel oil was prepared according to the national standard.Finally,the effects of the addition of alcohols on methanol solubilization of methanol emulsified diesel oil were investigated.The main results are as follows:Firstly,the stability and dispersibility of methanol emulsified diesel oil were studied.The optimum ratio of the emulsifier is: ?(oleic acid): ?(Span-80): ?(OP-10): ?(Tween-80): ?(sodium carboxymethyl cellulose)= 14: 5: 2: 1: 5,the HLB value is 4.48.Through single factor experiments,the optimum operating parameters are obtained as follows: the emulsifier content is 5%,the methanol content is 10%,the speed of the high-speed disperser is 5�2800 r/min,the high-speed dispersion time is 5min,the ultrasonic action time is 25 min,the ultrasonic power is 280 W,and the emulsifier HLB value of the compound emulsifier is in the range of 4~6,the emulsion stabilization time is 15 days.On the basis of single factor experiment,the response surface method was used to optimize the operating conditions.The results show that this model is useful for the optimization of the process conditions for methanol to emulsify diesel oil.The optimal operating conditions are as follows: ultrasonic action time is 20 min,ultrasonic power is 220 W,methanol content is 10%,emulsifier content is 5%.The theoretical and experimental stabilization times of methanol emulsified diesel oil are 456 h and 444 h,respectively.The relative deviation between the experimental results and the predicted values is 2.69%.The results show that the average diameter of methanol droplets increases with the increase of methanol content and decreases with the increase of emulsifier content.Under suitable operating conditions,the Sauter average diameter(D)of methanol droplets is 13.0 ?m.And then the rheological and physical and chemical properties of methanol emulsified diesel oil were studied.The results of rheological experiments show that the methanol emulsified diesel oil is Newtonian type fluid.The viscosity of methanol emulsified diesel oil is almost constant with the increase of ultrasonic time and ultrasonic power,the viscosity value is approximately 3.98 mPa�s,in line with the national 0 # diesel viscosity standard.The effects of various factors on the physical and chemical properties of methanol emulsified diesel oil are investigated.The experimental results show that the flash point and freezing point of methanol emulsified diesel oil decreases with the increase of methanol content and increases with the increase of emulsifier content.The increases of methanol content lead the increase of corrosion degree of copper sheet.The color of emulsion increases with the increase of emulsifier content.Under suitable operating conditions,the flash point is 65?,the freezing point is-8?,the copper corrosion grade is 1a and the Chroma is 1.5.The physical and chemical properties of methanol emulsified diesel oil prepared under the experimental conditions meet the national standard of 0# diesel fuel.Finally,the effect of the addition of the emulsifier on the methanol addition was studied.The experimental results show that when the addition of the emulsifier is n-butanol and the ?(complex emulsifier): ?(n-butanol)is 9: 1,the methanol content of methanol emulsion diesel is up to 43%,and the emulsion stabilization time can reach to 460 h.The addition of methanol is increased by 33% comparing to the absence of the emulsifier alcohol.The experimental results of the addition of isomeric alcohols to methanol show that the effect of linear rectal alcohols is better than that of isomeric branched alcohols.In order to play a good role,the polarity of the co-emulsifier is in the range between methanol and diesel oil.Different preparation methods directly affect the stability and dispersibility of methanol emulsified diesel oil,which has little effect on rheological and physical and chemical properties.