Investigation of blocking phenomena in cleaning of micro heat exchangers

Abstract Micro heat exchangers enhance heat and mass transfer compared to conventional heat exchangers which promotes an increased energy efficient application in many industries. Despite these advantages, micro structured components in general are prone to fouling and therefore to blocking phenomena which limits their industrial application. Since fouling is not always avoidable, cleaning strategies are essential and have to consider phenomena which are specific for micro structured components. Since swelling always occurs at the beginning of the cleaning of protein-based deposits, leading to an increase in the deposit volume and thus to a reduction in cross-section, blockage and a corresponding process interruption may still occur even during cleaning. In order to be able to develop an automated cleaning process for micro heat exchangers, swelling and associated blocking phenomena need to be identified first to control swelling during cleaning. For experimental investigations, a dyed model soil system is cleaned first in a diffusion-based setup to investigate the swelling and dissolution without flow impact and afterwards in a one-dimensional micro structured flow channel through the circulation of a sodium hydroxide solution. First results indicate options to reduce swelling and thus to prevent blockage during cleaning.