음향트래핑을 이용한 미세조류 분리에 관한 연구

Abstract

The amount of energy resources of oil, coal, natural gas used in the world was geometrically increased by industry development. Alternative energy development is studied in order to solve energy shortage phenomena. Microalgae as future energy and resource were received worldwide attention. Microalgae produced the industrial materials and reduced carbon dioxide through photosynthesis. Not only mass culture system but also harvest of large quantities is required to microalgae resources. The ultrasonic wave is sometimes used to separate microalgae. In this study design and sound field analysis was carried out in order to accomplish ultrasonic wave separation processes. Resonator design was composed of a multilayer resonant structure. Excitation frequency was analysed by the sound field and waveform in the resonator was predicted. Characteristics of microalgae in the acoustic trapping were investigated by experiments. The experiment was conducted according to the size of particle, input power, microalgae concentration, change of flow rate ratio. Three species of microalgae was experimented and the small particle size was the advantage of separation. The separation efficiency was increased at higher input power but thermal energy loss considered according to input power increases. The separation efficiency was increased at higher microalgae concentration but separation efficiency was decreased above a certain concentration. Flow rate was a great influence on the separation efficiency and the slow flow was advantage of separation efficiency. In order to predict ultrasonic separation efficiency on the basis of experimental results, the statistical method and the spatial modeling were used. The plural array and the multiple regression model were used as the statistical method. Accuracy of the prediction equation was decided by estimation and test. The spatial modeling was set up an state equation for dynamic characteristics of ultrasonic wave separation dividing the resonator by three. Ultrasonic separation scale-up resonator was designed to increase the processing capacity. Separation capability of microalgae was predicted through the sound field analysis for resonator design. The microalgae separation technology using ultrasonic wave according to experiment results and analysis results could be applied for the bulk harvest process.