Evaluations of porous burner characteristic diagrams and process water production possibilities

Abstract

In recent years, there has been a trend to new developments in gas and oil burners, which have been dominated by the aim of reducing pollutant emissions, reducing burner size and increasing the power modulation range. Several methods have been proposed in order to obtain more efficient combustion systems with low pollutant emissions. Over the past few years, a great deal of investigation on combustion in porous medium has been performed. In its efforts to optimize combustion processes, the Institute of Fluid Dynamics in Friedrich-Alexander University, Erlangen (LSTM-Nürnberg/Germany) has succeeded in developing the technology of combustion in porous media and this burner was used in this study. This thesis was focused on the evaluation of the porous burner characteristic diagrams and determined the possibility of the process water production. The experimental works were consisted of two main parts. One of them was carried out at the Institute of Fluid Dynamics in Erlangen. The second was performed at Izmir Institute of Technology. The aim of the experimental work for 25 kW porous burner was to analyse temperature distribution of exhaust gases close to the outer surface of ceramic matrix as well as pollutant emissions as a function of the burner surface. The aim of the second part was to investigate pollutant emissions as a function of the burner power and excess air ratio numbers, analyse the exhaust gases and cooling water temperature distribution with respect to burner power. Liquefied Petroleum Gas (%70 Butane + %30 Propane) was used as a fuel, which is utility gas in Turkey. It was concluded that the 25 kW burner allow very stable combustion with turn down ratio of around 6:1, and 4:1 for 10 kW burner, and excess air ratio numbers in the range 1.40 - 2.0. The exhaust gas temperature could easily reach 1100°C with a more and less uniform distribution over the 25 kW burner.s exit surface area. It was noticeable that the emission values lie lower than the values given by both German Norm 4702 and International Energy Agency, for 25 kW porous burner. CO an NOX emission values for 10 kW porous burner were quite lower than the emission limits for large new combustion facilities in Turkey. The burner showed that considerable amount of heat was transferred from exhaust gas to cooling water. Finally, porous burner can be used for process water production in various fields of energy engineering.