Development of Hydrogen Burners and Vacuum Insulated Furnaces for Zero CO ₂ Emissions

The prevention of global warming has been a primary concern of the automotive industry for some time. The Toyota Environmental Challenge 2050 describes six individual initiatives to help build a future in which people and vehicles can coexist in harmony. These initiatives aim to eliminate CO₂ emissions in vehicle manufacturing by 2050, as well as reduce CO₂ emissions while driving. Heating-related processes were identified as being responsible for around 50% of plant CO₂ emissions, the most significant single factor. Consequently, as the first step toward achieving zero plant CO₂ emissions, the following two technologies were developed with the aim of reducing CO₂ emitted in heating processes: (1) a hydrogen burner that generates CO₂-free heat and (2) vacuum-insulated furnace walls that enable energy-saving and smart use of heat. These two items were combined into a heat management system with the aim of reducing CO₂ emissions by 80%. One issue of hydrogen burners is reducing the generation of NOx at high flame temperatures. Adopting a new structure with two-stage combustion lowered the flame temperature and reduced NOx to the same level as a city gas burner. In addition, one issue of vacuum-insulated furnaces is achieving a thermal insulation performance that reduces the amount of heat dissipation from the furnace by 80% while ensuring sufficient strength for a service life of at least seven years. This issue was resolved by using a double-piped vacuum-insulated wall with an internal vacuum effective against the three elements of heat dissipation (convection, conduction, and radiation), and adopting a structure capable of absorbing the difference in thermal expansion of the inner and outer walls. The system that combines these two technologies is capable of reducing plant CO₂ emissions by around 80%. This paper describes the details of these two technologies.