Abstract: According to the request of the experiment, the variable frequency controlled waveform ultrasonic emulsification device was designed. Optimal operating parameters of ultrasonic generator were studied by orthogonal experiment. The preparation conditions of the emulsified liquid were: HLB=5, dosage of emulsifiers 3%, addition of bio-oil 20%, 0^# diesel 80%, methanol used as auxiliary emulsifier, and emulsifying temperature at the room temperature. 40 mL of emulsified liquid was added to the variable frequency controlled waveform ultrasonic emulsification device to emulsify. According to the results, treating time had the most significant influence on the stability, followed by power, frequency, and waveform. The optimal operating parameter was power of 30 W, frequency of 25 kHz, treating time of 8 min and waveform of square wave pulse. The emulsification stability under these conditions was the best and the setting time was 2 256 h.

Key words: lignocellulosic bio-diesel fuel, ultrasound factors, emulsification stability, operating parameters, orthogonal experiment