Newly
developed structures reduce NOx emissions to below natural gas
burner levels, zero CO2 emissions from combustion
Toyota Motor Corporation (Toyota) has developed the
world’s first1 general-purpose hydrogen burner for industrial use in
collaboration with Chugai Ro Co., Ltd. The burner is already used at the
forging line in Toyota’s Honsha Plant.
In conventional hydrogen burners, hydrogen reacts rapidly
with oxygen, leading to a high flame temperature and environmentally hazardous
NOx emissions. On account of this, the practical use of hydrogen
burners has proved challenging. The newly developed burners incorporate two new
structures that enable hydrogen to combust more slowly. The new burners also have
zero CO2 emissions and greatly reduced NOx emissions2,
resulting in outstanding environmental performance.
1) Preventing hydrogen and oxygen
from mixing completely
If hydrogen and oxygen are in a fully mixed state when
ignited, the mixture burns violently with a high flame temperature. In the newly
developed burner, hydrogen and oxygen
flow side-by-side and are ignited without being fully mixed, leading to
slower combustion and a lower flame temperature.
2) Lowering
oxygen concentration inside the furnace
If the
fuel mixture contains a high concentration of oxygen at the time of ignition,
combustion is violent with a high flame temperature. To prevent this, small holes are opened in the pipes that supply
hydrogen to the burner, enabling small volumes of hydrogen and oxygen to
pre-combust. Oxygen concentrations are consequently reduced to an optimal
19-percent level for main combustion, resulting in a lower flame temperature.
To achieve the targets set out
in its Plant Zero CO2 Emissions Challenge, which forms part of the
Toyota Environmental Challenge 2050, Toyota is implementing innovative
technologies and everyday kaizen (continuous
improvement) activities. Toyota also aims to use energy in its plants that comes
from renewable sources, including hydrogen energy.
The
new technologies announced today will enable 1,000 large-scale natural gas
burners to be replaced by hydrogen burners at our plants across Japan. Conventional
technology is responsible for significant volumes of CO2 emissions; to
realize its Plant Zero CO2 Emissions Challenge, Toyota is planning
to install hydrogen burners gradually at its other plants, and other companies
in the Toyota Group are also considering installation.
Going
forward, Toyota seeks to realize a hydrogen-powered society and reduce its industrial
carbon footprint by promoting industrial hydrogen use and by contributing to
increased demand for hydrogen.
