Development of Hydrogen Burners and Vacuum Insulated Furnaces for Zero CO
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.