The ceramic tile industry is an energy-intensive industry, mainly in terms of natural gas consumption, with a total consumption of 16,000 GWh/year. The level of CO2 emissions in the cluster reaches 3,350,000 tCO2/year, approximately 90% of which come from the combustion of natural gas. In this context, the European Green Pact proposes a 55% reduction in emissions compared to 1990 by 2030 and zero emissions by 2050.
With such ambitious emission reduction targets, the sector will have to radically modify the technologies used in its production process. One of the existing options is the use of hydrogen as a direct source of thermal energy by combustion in the drying and cooking processes. The great advantage of this process is that its combustion only produces water vapour, and if the energy for its production is of renewable origin, its associated CO2 emissions are very low, with zero direct emissions, and therefore of great interest for achieving the planned decarbonisation objectives.
However, the use of hydrogen as a fuel in industrial processes requires a detailed study to determine the influence that the gaseous atmosphere resulting from the use of hydrogen as a fuel exerts on the physico-chemical reactions that the processed materials will undergo.
This study presents the results obtained in a temperature-controlled tubular kiln, designed to study the influence of the kiln atmosphere on the firing behaviour of three types of ceramic substrates (tile, stoneware and porcelain stoneware). To this end, sintering curves have been obtained for these materials using seven gas mixtures modifying the proportion of N2, O2 and H2O. The results are interpreted on the basis of the influence of these gases on the viscosity of the glass phase and on the redox reactions of some metal oxides.
This project is supported by the Generalitat Valenciana, through the Instituto Valenciano de Competitividad Empresarial (IVACE) through the Nominative line.