Evaluating energy utilization and exergy in decorative ceramic kilns: A novel approach to thermal efficiency and sustainability

Abstract

The ceramic industry is a major consumer of resources and greenhouse gas emissions. Although the nature and volume of the energy consumption and gaseous emissions have been assessed in ceramic production; there appears to be a lacuna in literature on en ergy utilization and the firing process of decorative ware ceramic. In view of this, a novel method of combining heat flux, displacement and availability, based on the first and second laws of thermodynamics was used to evaluate the combustion processes and energy utilization of a decorative ware kiln. The results showed that 5, 936, 25 5.42 kj/kmol was available for useful work, 605,520.42 kj/kmol for displacement, and 119,065.0 kj/kmol for work against limiting forces. The outcome also revealed that, while 1034.7 kj/kgk of latent heat was used for the vitrification of the wares; 208, 4725 kj/kgk of thermal energy was lost. Similarly, as the combustion temperature progressed to 1000OK, there was an increase in heat flux through the chimney, with thermal energy loss of up to 40.21% through conduction. The study therefore concluded that thermal energy loss through the chimney was higher than at any point in the kiln structure, thereby making the entire firing process inefficient and unsustainable.