Developments in the production of hydrogen by thermochemical water decomposition


Faculty of Engineering and Applied Sciences, University of Ontario Institute of Technology.


Recent developments in hydrogen production by thermochemical water decomposition are reported,
with an emphasis on hydrogen production from non-fossil energy sources such as nuclear and solar. Numerous
developments have been made on sulphur-iodine, copper-chlorine and other thermochemical
cycles. Efforts are described to lower the temperatures required in thermochemical cycles, so as to broaden
the range of potential heat supplies, including developments in the copper-chlorine thermochemical
cycle, which has significant potential due to its requirement for process heat at lower temperatures than
most other thermochemical processes. The thermodynamic evaluation of thermochemical water decomposition
processes is explained and illustrated by applying informative methodologies like exergy analysis,
which can assist in improving efficiencies and identifying limiting efficiencies. Thermochemical water
decomposition has several advantages relative to other hydrogen production processes that could make
it a competitive future option for hydrogen production, which is a key component of a hydrogen economy.
Recent developments, particularly using such non-fossil energy sources as nuclear and solar, suggest
that thermochemical hydrogen production could become commercial, and help meet the anticipated future
demand for hydrogen as an energy currency in the context of a hydrogen economy. Consequently, research
is likely to continue to improve thermochemical water decomposition processes.