We estimated on the stability of W/O type emulsified fuel using by capacitance sensor, so it concluded the following conclusions. For the first 24 hours, prepared emulsified fuel reveals phase separation ratio of 5%, maintains stable status which verifies the stability of emulsified fuel. Adding more water increases the phase separation ratio rapidly, and adding more surfactant displays stable emulsification. Adding water causes larger size of water droplet diameter, and adding surfactant mixture causes smaller size of water droplet diameter. In conclusion, the size of W/O type emulsified fuel water droplet diameter is directly related to the volume of surfactant, and density of water droplet diameter changes thedistribution according to water contents.

In this study, the characteristics of emulsified fuel were studied. The emulsified fuel which was composed of water and diesel was manufactured by using homogenizer and ultrasonic generator. The more the percentage of water contents increases, the more the density increases to the emulsified fuel. However, the viscosity increased in the 60% of water contents and decreased in the 70% of water contents because the O/W type was formed. The 3 minutes's ultrasonic waves during the irradiation time was appropriate of 16,000 rpm. And the energy density of ultrasonic waves was 87.5J/g. The emulsion stability has improved in the lower temperature, the lower percentage of water contents, and the most stable emulsion state was obtained from 20%(w/w) of water contents. Also, the emulsion stability was related to the HLB values of emulsifiers. Especially, the HLB values of emulsifier were appropriate from 4 to 7 values.

We designed capacitance sensor in order to examine characteristics of W/O type emulsified fuel, so it concluded the following conclusions. The capacitance value of emulsified fuel, using with capacitance sensor, increases as water content increases due to the coalescence. When surfactant increases, the capacitance value decreases, the condition of W/O type emulsified fuel was maintained stably. There was revealed the capacitance value difference of W/O type emulsified fuel in in according to water content. We checked the phase separation of emulsified fuel with the capacitance value difference. The surfactant(HLB=5.4) had better stable condition than surfactant(HLB=4.3). Also, we confirmed that two mixture surfactants were better than one surfactant.

최근 화석에너지의 한계성에 따른 에너지 위기를 대비하여 석유대체연료의 필요성이 강조되고 있다. 석유대체 연료에는 바이오디젤, 바이오에탄올, 유화연료유 등이 있다. 이 중 유화연료유는 중유, 물, 유화제를 혼합하여 제조한다. 유화연료유의 입자는 미세한 수분입자가 기름 속에 함유되어 있는 유중수적(water in oil) 형태를 가진다. 기름보다 비등점이 낮은 유중수적의 수분입자는 기화에 의해 체적팽창을 일으켜 기름의 미세화를 유도한다. 미세화에 의해 비표면적이 커진 기름은 산소와 혼합이 유리하게 되어 완전연소를 유도한다. 그 결과, 연소효율의 증대, 연소 미립자 생성 억제, 공해물질 생성 억제 등의 이점을 가져온다. 본 연구에서는 유화연료유의 재료인물과 유화제를 대신하여 축산폐기물인 돈뇨와 B-C유를 혼합한 유화연료유의 생산을 검토하였다. 유화연료유의 생산에서 돈뇨를 이용할 경우, 돈뇨 처리의 비용적 부담을 줄여줄 것이다. 또한 돈뇨의 특정 성분은 물과 유화제보다 유수분리를 지연시켜, 품질 좋은 유화연료유를 생산할 수 있을 것으로 사료된다.