화학공학소재연구정보센터
Journal of Food Engineering, Vol.121, 1-8, 2014
Composition of milk fouling deposits in a plate heat exchanger under pulsed flow conditions
Fouling deposition on heat exchangers in milk plants is the main reason of progressive decline in efficiency and performance during operation. In order to increase operational effectiveness an anti-fouling strategy based on the adjustment of the hydrodynamic flow conditions was investigated. For this purpose stationary flow was superimposed by an oscillating flow, resulting in temporary high values of the wall shear stress. Experiments were conducted using a commercial stainless steel pilot scale plate heat exchanger (PHE) with a calcium phosphate-rich whey protein solution as model fluid. The PHE system was operated at a product side flow rate of 0.085 m(3) h(-1) (v=0.1 m s(-1), Re = 870) heating the solution from 62 to 85 degrees C. The results show that the build-up of fouling layers as well as the fouling layer composition was strongly dependent on the flow conditions. The pulsation amplitude and mode mainly influenced the mineral deposition and a reduction of fouling was achieved. Hence, the use of pulsed flow provides an opportunity for the mitigation of milk fouling. (C) 2013 Elsevier Ltd. All rights reserved.