Currently, as is the case in other energy-intensive sectors, high-temperature tunnel kilns fired with natural gas are used for firing products in the industrial brick and heavy clay industry. The production processes show correspondingly high energy-related CO₂ emissions. In addition, there are significant process-related CO₂ emissions, due to the release of carbonates contained in the clay and the combustion of additives.
A promising environmentally friendly alternative is electric kilns powered by green electricity. To date, however, this technology has only been implemented for small to medium-sized plants and batch processes. There are also promising carbon neutral alternatives for porosification agents, which are necessary to achieve good thermal as well as sound insulation, and which still need to be tested and evaluated in large-scale applications.
„We are aware of our responsibility as market leader. In the GreenBricks project, we are setting new global standards in industrial brick production with regard to energy efficiency and CO₂-emissions.“
In order to decarbonise the industrial production of bricks, GreenBricks pursues the following goals:
In order to optimise the process of brick production holistically, various tools / technologies are being developed in GreenBricks. This includes, above all, the creation of a digital twin of the dryer-burner-heat pump heat network as well as a model for techno-economic optimisation at the plant level.
In a further step, new recipes for clay mixtures with a minimal CO₂ footprint will be developed. This requires sophisticated screening, testing and optimisation procedures. The newly developed mixtures are tested and optimised in the brick molding/extrusion process, in the dryer and in the kiln under real production conditions and at various Wienerberger locations.
To optimise the overall energy efficiency in the dryer - burner - heat pump heat network, the design of the tunnel dryer and its internal and external heat recovery technologies including an absorption heat pump will be analysed and adapted.
The gas-fired burner will be dismantled and replaced by a new type of electrically fired high-temperature kiln. The heat distribution in the kiln will be optimised at different levels using various models to be developed in the project. The new kiln will then be commissioned step by step and tested and evaluated up to a production capacity of 300 tons of bricks/day.
In a further step, the introduction of the technologies at plant level within the Wienerberger Group will be prepared and techno-economic site analyses of at least five plants in three countries will be carried out. In addition, CFD models will be used to evaluate the extent to which the knowledge gained in the project can be technically transferred to the electrification of batch and continuous kilns for the manufacture of other ceramic products or in other sectors.
Finally, an intensive dialog with relevant industrial, public, and political stakeholders is planned. This is to ensure that the concepts/technologies developed are socially accepted, ecologically compatible and economically feasible. In addition, extensive networking activities are planned to promote a broad use of the project results and findings in other ceramic sectors as well as industries that also use gas-fired burners on an industrial scale, and to initiate further research projects.
The project should lead to the following results: