Utilising a high pressure, cross flow, stainless steel fintube heat exchanger for direct steam generation from recovered waste heat

[摘要] ENGLISH ABSTRACT:Around the world the implementation of heat recovery systems is playing an increasinglyimportant role in the engineering inqustry. The recovered energy is utilised in the plantsand saves companies millions in expenses per year. Not only is this seen on the grandscale of industry, but also in everyday life, where for instance turbochargers are used toboost the performance of automobiles by utilising the wasted energy expelled along withexhaust gasses.The aim of this project is to investigate a small scale waste heat recovery system, and todetermine the optimum method by which to convert the recovered energy into electricalenergy, which can be used as a secondary energy source.The research contained in this thesis, centres on the main components and theory neededfor the construction of a small scale waste heat recovery system. Also included, is atheoretical analysis concerning the design and construction of the system, utilisingresearched theory and a simulation program of the recovery system. The simulation iscontrol volume-based and generates property data on the fluid and exhaust gas throughoutthe heat exchanger.The final design included a finite element stress analysis of certain parts of the system toensure safe testing at high pressures and temperatures.The final design resulted in a high pressure, cross flow, stainless steel fintube heatexchanger that, by using a continuous combustion unit as energy source and water as theworking fluid, reached efficiencies of up to 74% in direct steam generation testing. Thetube-side of the heat exchanger was designed to withstand pressures of up to 2MPa(20bar), which is imperative for the implementation of the next phase, where aturbocharger will be connected to the heat exchanger.The completion of this part of the project has paved the way for further development andimplementation of the heat recovery system.

[发布机构] Stellenbosch University