Development Of A New On-Line Monitor On Fouling Resistance And Its Applied Research

Fouling is found all over the nature, daily life and most of industrial processes, especially in all heat transfer processes. The economic losses caused by fouling are as high as 0.25% of Gross National product. There are lots of factors affecting the fouling accumulation. Though many scientists have devoted a great on it, the fouling is still an unresolved problem in heat transfer field and the researches are mainly depend on experiments. Therefore, the meaning of the research in fouling monitoring technique and equipment is great. Based on our groups' former studies, a new universal fouling resistance monitor was developed and all corresponding functions were thoroughly studied.According to the on-line fouling resistance monitoring technique and comparison between domestic traditional dynamic simulation experimental methods and foreign advanced fouling monitoring equipment, we designed a new double-tube and double-circuit on-line fouling resistance monitoring equipment and developed corresponding system managing software by Delphi5.0. In order to win the versatility and reliability of the device, all design requirements of equipment such as multi-function, adaptability of operating mode and reliability were fulfilled. Through two years' experimental verification and a series of improving of performance, this equipment reaches the first-rate property-price ratio.By means of the development equipment and the on-line monitoring technique, the correlations between fouling thermal resistance and geometric parameters of three kinds of enhanced heat transfer tubes,such as transversally corrugated tube, spiral-grooved tube and arc line tube were evaluated and semi-industrial experiment research of corrugated tube was carried out. The results showed that the fouling characteristics of corrugated tube, transversally corrugated tube and arc line tube are better than that of plain tube, while spiral-grooved tube is worse than plain tube. It presented reliable theoretical basis for optimizing the enhanced tube design.For lack of the fundamental investigation on water treatment technique and anti-fouling effect evaluting technique,the equipment developed in this paper was applied to assess the anti-fouling effects of water treatment by dynamic simulation experiments. We studied the choice of chemical anti-fouling agent and performance evaluation of ion-rod static water treatment equipment respectively. The experiments fully showed the anti-fouling performance of agents and static equipments. Meanwhile, the results of the above experiment investigations also demonstrate the feasibility of the development device used for evaluating anti-fouling effect.Taking aim at the problem of flow measurement in the anti-fouling evaluation experiments, this paper presented a soft-sensing method to measure the flow on the basis of heat balance theory and calibrated it against weighing method, which was the important basis on improving the practicability of the developed device.As to the prediction analysis of fouling characteristics, this paper applied the time series analysis to do trial research. It reached acceptable precision within fifteen steps and made useful preparation for further improving the prediction period.