Stability Of Bio-oil Model Compounds/diesel Fuel Emulsions

Biomass pyrolysis is one of the main methods to use biomass with high-value,which can convert low quality biomass into high quality bio-oil.However,the bio-oil obtained from pyrolysis has the disadvantages of high moisture content,low calorific value,high viscosity and strong corrosive,which can not be used directly as high quality fuel.Bio-oil emulsification technology is simple in processing and does not require complex chemical reactional.The emulsification technology can produce stable bio-oil/diesel emulsified fuel,which can be used as a fuel in the diesel engine.The chemical composition of bio-oil is very complicated and the contents of bio-oil components vary greatly with the changes in the pyrolysis conditions.Different components require different emulsifiers for the emulsification.In order to study the effects of the major components in bio-oil on the characteristics of emulsions,bio-oil model compounds/diesel emulsification experiments was conducted in laboratory.The model compounds used were acetic acid,ethanol,furfural,phenol and deionized water.Span80,tween80 and octanol was used as surfactant,co-surfactant respectively.Bio-oil model compounds emulsion was prepared by pre-emulsion of electromagnetic agitator and emulsion of ultrasonic cell crusher in order to investigate the stability of bio-oil model emulsion.The optimum HLB value of stable bio oil / diesel oil emulsion was calculated by analyzing the components of corn stalk bio-oil,then compared with bio oil/ diesel test.Acetic acid,ethanol,furfural,phenol and deionized water were used to emulsify diesel oil,respectively.When the surfactant volume fraction was 8.6%,the stability time of acetic acid / diesel oil and ethanol / diesel oil was more than 180 days.Deionized water / diesel oil emulsion was viscous,and the stability of deionized water / diesel emulsion was better,when the volume fraction of surfactant was 4.6%,the ratio of Span80 to Tween80 was 5:1.The experiment results show that when the ratio of diesel fuel,bio-oil model,surfactant,co-surfactant are 8:2:1:0.6,the stability of emulsion is the best.However,the emulsion compounded by furfural has disadvantage of fast delaminating and destabilizing.This shows that stable emulsion of furfural could not be prepared when combined with others bio oil model.The phenol emulsion compounded with ethanol has the best stability,the time of emulsion stability is more than six months,and the average particle diameter is about 2.49?m.The experimental results show that the solubilization of phenol was related to ethanol in diesel oil.When the volume fraction of surfactant is 2.4%,the calculated values are different from the experimental results;When the volume fraction of surfactant is 4.6%?8.6%,the optimum HLB value of the emulsion is 7.41,which is consistent with the experimental results.