악성폐수 처리를 위한 강하경막 동결농축 기술의 성능에 미치는 영향인자

Abstract

Influence of various design and operational factors on the performance of a falling film freeze concentration system for wastewater treatment was experimentally investigated. The ice growth rate on the inner surface of freezing tube was dependent on the hydraulic characteristics of the falling wastewater flow. The inclusion of pollutants into the ice crystal was reduced by the increase of turbulence in the falling flow, which was as a result of the increased the diffusion and convection of pollutants at the interface of ice and falling wastewater flow. The inclusion of ionic substances into the ice was higher than that of non-ionic organic substance, but the difference was reduced at turbulent regime in the falling flow. The inclusion of anions into the ice was affected by the electro-negativity, but for cations, by their ionic radius. As raw material for freezing tube was replaced from stainless steel to copper with higher heat conductivity, the ice growth rate was significantly increased by the increased heat transfer, but the inclusion of pollutants into the ice crystal was also increased. In order to improve the performance of falling film freeze concentration system, influence of electromagnetic field on the separation of pollutants and ice growth rate were investigated. During the growth of ice under the electromagnetic field, the inclusion of pollutants into the ice was reduced without significant loss of ice growth rate.