RSA Rubis is the European leader in the production of synthetic sapphire. This leadership is based on their mastery of a sapphire manufacturing process. This crystal growth technology currently relies on the use of an oxygen / hydrogen diffusion flame whose high temperature allows the melting of particles of alumina, the main constituent of sapphire.

The company today faces two major issues:

- improve the quality of its crystals while maintaining or lowering its production costs in order to respond to the emergence of competitors using new crystalline growth technologies

- respond to the evolution of its hydrogen supply sources by using an alternative fuel in its historical process.

To meet these challenges, RSA Rubis decided to increase its research effort and turned to CETHIL, which conducts research activities in the field of combustion, more specifically on heat transfer in reactive media. Studies have enabled the two partners to identify two priority areas for research:

• The improvement of the historical process using hydrogen, with a global approach on the analysis of the causes of variability of the quality of the crystal, then focused on the most influential mechanisms on the process (presence of water vapor in the fuel, thermal confinement of the burner, ..)
• Implementation of an innovative extension of this process to fuels of different nature.

The scientific issues to be developed are numerous, and their implications go beyond the scope of this collaboration to address in a global way the technological challenges related to industrial burners:

• Stabilization of non-premixed flames.
• Flexibility of burners when using new fuels.
• Anticipation and management of constraints related to changes in the reactive environment (thermal stresses on the burner, production of pollutants).

The RAINBOV LabCom, for Research, Analysis and Innovation for Verneuil Crop Burners , makes it possible to mobilize the necessary resources, give medium-term visibility and boost collaboration between RSA Le Rubis and CETHIL. This joint laboratory also demonstrates the willingness of both partners to establish a long-lasting synergy that will allow RSA Le Rubis to support its innovation strategy and CETHIL to broaden the scope of its own research to address scientific and technological issues. , in connection with the regional industrial fabric.