Situation of the waste-heat utilization in the German glass industry Survey results

Abstract

The overall energy consumption in the glass industry is controlled generally by the energy components that have been installed for glass melting. Because of the high processing temperatures, the use of effective air-preheating systems is an essential prerequisite for the efficiency and economy of today's operating glass-melting furnaces. Since the temperature of the waste gas after exiting the furnace installation is generally of the order of 500 °C, the utilization of the waste heat contained in the waste gases by means of special heat-recovery units has been pursued for a long time by numerous glass works. In the framework of a survey it was determined to what extent waste heat recovery systems are utilized in the glass industry of West Germany and for what purpose the energy obtained in this connection is being utilized. Over 60 % of the plants that were questioned have installed waste heat recovery units, and the waste heat that is available to these plants represents about 75 % of the total waste heat available to the glass industry. In further evaluations which took into account not only the waste gas volume flow of the entire plant but also the volume flow from the individual glass-melting units, it was shown that waste heat recovery units are clearly economically more favorable for the larger plants.