Experiment Research On Preparation Of Bio-oil/Diesel Emulsion Fuel

In the past years, lots of efforts were done to push forward the biomass fast pyrolysis technology. Now, biomass waste can be efficiently converted into liquid bio-oil with this fast pyrolysis technology and high crude bio-oil yield was also achieved. However, the crude bio-oil still has some disadvantages, such as high water content, low heating value and high acidity. Bio-oil refinement is the key process before its high-grade utilization. Emulsification technology is process simple and cost low, if it can succeed to improve the bio-oil quality, which will greatly promote the bio-oil utilization process.In this paper, mechanical emulsification and ultrasound emulsification technologies were adopted for preparing bio-oil/diesel emulsion fuels. The effects of HLB values on emulsion fuels stability were studied, and the best emulsifier HLB value of7was found. The relationship between operating conditions and emulsion fuels stability was studied, such as the emulsification intensity and treating time, it was found that fuels stability can be improved with the increasing of ultrasound power. Emulsion fuels could reach the best stability after5minutes emulsification when the rotational speed was15000r/min in mechanical emulsification. The longest emulsion fuels stable time of55days can be reached with the combination of mechanical emulsification and ultrasound emulsification technologies.The surface tension of the bio-oil/diesel emulsion fuels made from different HLB values was tested, which indicated that smaller emulsion surface tension lead to longer stable time. The smallest surface tension was obtained under the optimal HLB value of7, and its surface tension increased as the storing time increased. The emulsion stability under different emulsion methods was investigated through particle size analysis. It was found that the droplet particle size of ultrasound emulsion fuels was smaller than that from mechanical method. The droplet size was0.3tolum in the fresh emulsion fuels which increased as the storing time going on. The change of the droplet size was attributed to collide and conglomerate of the small droplets.In this paper, ternary phase diagram method was used to simulate the bio-oil and diesel emulsification. It was found that bio-oil and diesel could be emulsified in any proportion if the emulsifier content was above15%, and the stable time could reach up to10hours. If the content of bio-oil was limited under10%, a emulsifier amount of5%was enough to maintain the stability of the emulsion fuels.