Research articles
Evolution of composite fouling on a vertical
stainless steel surface caused by treated sewage
1.Research Institute of
Petroleum Exploration and Developmen (RIPED), PetroChina, Beijing
100083, China；Key Laboratory for Thermal
Science and Power Engineering of Ministry of Education, Tsinghua University,
Beijing 100084, China; 2.Key Laboratory for Thermal
Science and Power Engineering of Ministry of Education, Tsinghua University,
Beijing 100084, China; 3.State-Key Laboratory
of Tribology, Tsinghua University, Beijing 100084, China;
发布日期：
2010-06-05
摘要
Composite biological and inorganic fouling occurs in plate heat exchangers (PHEs) using treated sewage as heat transfer medium, which lowers the heat transfer coefficient and increases the frictional resistance. In order to optimize the heat exchange process and improve the anti-fouling strategies, the dynamic behavior of composite fouling at a vertical surface of stainless steel (ANSI 316L) was investigated under typical conditions of PHEs. The growth curves of composite fouling were obtained. The evolution of composite fouling was characterized by means of environmental scanning electron microscopy (ESEM). Backscattered Electron Image (BEI) and energy dispersive X-ray spectrometry (EDS) were used as aids in interpreting the results. The experimental results show that a preliminary stage of a 6-day period with a low fouling growth rate exists during the composite fouling development. A significant change of the fouling growth rate happens after the preliminary stage during which the bacterial behaviors at the surface could be recorded clearly. After the preliminary stage, a space net-shape, mainly consisting of bacteria, extracellular products (EPS) and inorganic particles, could be established on the surface of the fouling layer. The change of fouling growth rate occurs synchronously with the evolution.
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