Research on the Characteristics of CaCO_3 Crystallization Fouling on Enhanced Heat Transfer Tubes

摘要

Enhanced heat transfer tubes are widely used in heat exchangers, and the characteristics of heat transfer and fouling are focused. Four kinds of tubes were tested at different temperature, initial concentration and velocity to study heat transfer and fouling characteristics. The results show that: the initial growth rate and final fouling resistance of fouling resistance decreases as velocity increases. But the influence of velocity gradually reduces when velocity is higher than some certain value. The fouling layer is compact and thin at high velocity, but thick and fluffy at low one. The fouling resistance does not always increase when concentration increases. Although the initial concentration is different, the concentration is similar after 8 hours. The final fouling resistance is similar at different concentration, but the morphology is different. The fouling resistance increases as the temperature increases. There is no fouling on the groove of ribs at low temperature, but opposite at high temperature. There is most fouling on the SOFT, more than PT. The scale inhibition performance of WSOFT is best and lest fouling. The NSOFT has a similar fouling resistance with PT.