Metrological performances of fouling sensors based on steady thermal excitation applied to bioprocess

Abstract

Food and industrial bioprocesses are impacted by (bio)fouling which generates failures from reduction of process efficiency (ex: reduction of heat transfer coefficient) up to health risk issue (e.g. biofilm formation). In present work, 3 fouling sensors based on a thermal excitation (steady thermal regime) were developed and described. These sensors were designed with different technologies (macro structure and Micro-Electro-Mechanical-Systems MEMS), geometries (intrusive cylindrical, flush plan) and packaging (presence or absence of cover panel) and compared. Laboratory setups were designed to characterize sensor responses under controlled operating conditions in batch and continuous process including clean condition and using layers of adhesive tape to simulate fouled conditions. Thermal responses from excitation under steady thermal regime at different heat flux were linearized then discussed as function of technology, geometry and packaging impacts. Packaging heat resistance, response times, efficient heat flux, and quantification of fouling were investigated. Finally, metrological limits were identified.