Title: Interaction effects of silica dioxide particles and calcium ions on the evolution of biofouling in plate heat exchangers relevant to a heat pump heat recovery system from treated sewage

Authors: Lei Tian; Xiao Dong Chen; Qianpeng Yang; Jinchun Chen; Lin Shi

Addresses: Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China. ' Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Fujian Province 361005, China. ' Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China. ' School of Life Sciences, Tsinghua University, Beijing 100084, China. ' Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China

Abstract: Heat pump using treated sewage water as heat source and sink is an effective way to reuse urban waste heat for building heating and cooling. However, fouling occurred in plate heat exchangers of the heat pump. An experimental system has been developed to investigate the interactions of inorganic particles (silica dioxide particles) and Ca²⁺ on biofouling properties. Process monitoring in biofilm have been conducted and presented with the view of attempting to reduce fouling in future. The results show that the interactions of the microorganisms, Ca²⁺ and inorganic particles clearly influenced the biofilm development thus impacting on the thermal resistance created. It was found that the fouling thermal resistance showed a different prospect than the fouled mass time trend under different inorganic particles in the presence of Ca²⁺. With inorganic particles added, Ca²⁺ facilities the increase of biofouling mass and thermal resistance.

Keywords: composite fouling; microorganisms; silica dioxide particles; calcium ions; thermal resistance; microstructure; biofouling; plate heat exchangers; heat pumps; heat recovery; treated sewage; wastewater treatment; urban waste heat; process monitoring; biofilm.

DOI: 10.1504/IJMPT.2012.048191

International Journal of Materials and Product Technology, 2012 Vol.44 No.1/2, pp.67 - 76

Published online: 17 Sep 2014 *

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