A great quantity of thermal energy is consumed in ceramic tile manufacture, mainly in the firing stage. The most widely used facilities are roller kilns, fuelled by natural gas, in which more than 50% of the energy input is lost through the flue gas and cooling gas exhaust stacks. This paper presents a calculation methodology, based on certain kiln operating parameters, for quantifying the energy saving obtained in the kiln when part of the cooling gases are recovered in the firing chamber and are not exhausted into the atmosphere. Energy savings up to 17 % have been estimated in the studied case.Comparison of the theoretical results with the experimental data confirmed the validity of the proposed methodology. The study also evidenced the need to improve combustion process control, owing to the importance of the combustion process in kiln safety and energy efficiency. KEYWORDS: ceramic tile, roller kiln, heat recovery, energy efficiency HIGHLIGHTS:Some energy input (30 -35%) in ceramic roller kilns is lost through the cooling gas stack.Cooling air is directly recovered in the combustion chamber, providing oxygen. This energy recovery from the cooling gas stack has been quantified.It has been proven that the proposed methodology to estimate energy savings is valid.

España y Brasil son dos de los mayores productores de baldosas cerámicas en el mundo. El proceso de fabricación de baldosas consume gran cantidad de energía térmica, y en estos dos países se obtiene principalmente de la combustión de gas natural, lo que conlleva la emisión a la atmósfera de CO 2 , gas de efecto invernadero. El objetivo del trabajo presentado es mostrar comparativamente los consumos de energía térmica y las emisiones de CO 2 en el proceso de obtención de baldosas cerámicas en España y en Brasil, atendiendo a las diferentes tecnologías de producción y a los distintos productos fabricados. El consumo energético y las emisiones de CO 2 son muy parecidos en ambos países, en el proceso de obtención de baldosas por vía húmeda. En el proceso vía seca utilizado en Brasil, se consume menos energía térmica, y se emite menos CO 2 , que en el proceso vía húmeda, pero es un proceso que se utiliza únicamente en la obtención de un tipo de producto en particular, que presenta algunas limitaciones técnicas. En España, el uso de sistemas de cogeneración en la etapa de atomización incrementa notablemente la eficiencia energética global del proceso. Los consumos energéticos medios de las diferentes etapas del proceso se sitúan, en ambos países, dentro del intervalo indicado en el Documento de Referencia sobre las Mejores Técnicas Disponibles en la Industria Cerámica de la Unión Europea (BREF de la Industria Cerámica). Palabras clave: consumo energético, emisiones de CO 2 , baldosas cerámicas, España, Brasil Thermal energy consumption and carbon dioxide emissions in ceramic tile manufacture -Analysis of the Spanish and Brazilian industriesSpain and Brazil are two of the world's biggest ceramic tile producers. The tile manufacturing process consumes a great quantity of thermal energy that, in these two countries, is mainly obtained from natural gas combustion, which entails CO 2 emission, a greenhouse gas. This study presents a comparative analysis of the thermal energy consumption and CO 2 emissions in the ceramic tile manufacturing process in Spain and Brazil, in terms of the different production technologies and different products made. The energy consumption and CO 2 emissions in ceramic tile manufacture by the wet process are very similar in both countries. In the dry process used in Brazil, less thermal energy is consumed and less CO 2 is emitted than in the wet process, but it is a process that is only used in manufacturing one particular type of product, which exhibits certain technical limitations. While in Spain the use of cogeneration systems in spray-dryers improves significantly the global energy efficiency. The average energy consumption in the different process stages, in both countries, lies within the range indicated in the Reference Document on Best Available Techniques in the Ceramic Manufacturing Industry (BREF of the Ceramic Manufacturing Industry) of the European Union. Keywords INTRODUCCIÓNLa producción mundial de baldosas cerámicas prácticamente se ha duplicado en los últimos diez años, y país...

No abstract