Energy efficiency enhancement and waste heat recovery in industrial processes by means of the heat pipe technology: Case of the ceramic industry

This paper investigates the application of heat-pipe based heat exchanger for improving the energy efficiency of industrial processes. In particular, the case of the ceramic industry is addressed and the potential heat recovery and reduction of fuel consumption is determined. A theoretical model is constructed based on the established, proven performance characteristics of heat-pipe technologies and the performance of the ceramic process are calculated using numerical simulation. The results of the kiln numerical model are then combined to the theoretical model of the heat-pipe based heat exchanger and the heat recovery potential is evaluated as well as the reduction of fuel consumption. The combined theoretical and numerical approach demonstrates that the application of the heat pipes based heat exchanger to the cooling stack of the ceramic kiln enables to recover more than 863 MWh of thermal energy that can be used for heating up the hot air stream of the pre-kiln dryer. Thus, approximately 110,600 Sm3 per year of natural gas can be saved from the burners powering the dryer and the emission of 164 tonnes per year of carbon dioxide can be avoided. Additionally, the avoided cost due to the fuel consumption reduction amounts to more than 22,000 Euro per year. These figures support the application of the heat pipes based heat recovery to the ceramic process from the viewpoint of the improvement the energy efficiency and environmental impact and also of the economic investment.