Abstract
Fouling is the unwanted deposition of soils on heat transfer surfaces and is a major challenge for industry and has been s subject to scientific investigations for decades, still being an unsolved problem for many applications. A fouling situation is commonly quantified with the thermal fouling resistance describing the integral fouling behavior of an apparatus. Modeling of this quantity is a permanent subject to research. This contribution presents the basics of an expanded consideration by introducing a holistic approach to model and link fouling resistances based on the extension of previous work in this field. A thermal and a mass based approach to calculate fouling resistances are considered integrally and locally. This will provide a detailed knowledge of the fouling behavior. Various variables are needed for modeling the different fouling resistances. Therefore, both experimental and analytical methods have to be applied to obtain the required data regarding local differences of crystallization deposits within double-pipe heat exchangers. Here the planned experimental and analytical approaches to receive all the required input data are described, also presenting the required test equipment briefly. Core equipment is a test rig equipped with double pipe heat exchangers, which allows the measurement of thermal and fluid flow related values and provides samples for the analysis of the fouling deposits. Furthermore, the aim of the new modeling concept is to link integral and local fouling resistances by taking into account locally varying parameters regarding the fouling layer. In order to allow for that, a recalculation of the thermal fouling resistance into a corrected version by considering heat transfer enhancing effects attempts to correlate with the mass based approach in a first step. In the end, the holistic modelling approach is presented.
Highlights
Fouling on heat exchanger surfaces is a severe issue in the chemical and process industry
With increasing crystal size and coverage of the heat transfer surface the surface roughness due to the deposit leads to an enhanced heat transfer resulting in an apparent negative thermal fouling resistance
A distinction is made between six target values: thermal and mass based as well as corrected fouling resistances, all considered locally and integrally
Summary
Fouling on heat exchanger surfaces is a severe issue in the chemical and process industry. On the other hand roughness and constriction result in an increased pressure drop, already appearing in the induction phase, see Fig. 1 These imposing trends require a distinction of the term fouling resistance into a thermal and a mass based fouling resistance. Experimental investigations of local thermal fouling resistances of CaSO4 deposits inside a double-pipe heat exchanger were presented by Goedecke et al [9] and Albert [13] Both found, that the integral assessment of the fouling process is not suitable to detect local processes or to identify the proceeding sub-processes and their interactions and to explain the determining mechanisms. Albert et al [8] developed a model to correct the integral thermal fouling resistance by taking roughness and constriction effects on heat transfer into account.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
