425
temperature. The thermal decomposition of glycerol to olefins was mainly responsible for the coking which severely affects the performance and is not suitable for
membrane reformer application.
Similar to ethanol, for glycerol too hydrogen yield at low temperature is very
low. Hence, for better integration, it is desirable to develop a low-temperature catalyst that can provide acceptable hydrogen flux for membrane reformer application.
5 Summary and Future Aspects
The focus of this chapter was mainly on providing an overview of the development
of membrane reformer concerning reforming catalyst for ethanol, methanol, and
glycerol steam reforming. The membrane reformer has the potential to be commercialized for on-board/on-site production of ultra-pure hydrogen. It can provide clean
energy when integrated with PEMFC and can reduce the dependency on fossil fuel.
However, the major challenge in commercializing the membrane reformer is its low
hydrogen recovery. This is linked to the performance of membrane used for selective hydrogen separation, the catalyst which is used for hydrogen generation, and
the way these two are integrated into a single assembly. Hence, it is required to
improve all these aspects to make on-board/on-site generation of hydrogen through
MR a reality. Here, I have discussed the reforming catalysts for different alcohols
which compete with each other based on application. The chapter highlights the
different catalysts used or tested for ethanol, methanol, and glycerol steam reforming and their suitability for membrane reformer application. Though several catalysts are available for ethanol steam reforming, mostly ceria-supported catalysts are
preferred as they provide low CO selectivity. Ni, Co along with some noble metal
like Ru, Rh are preferred as they reduce the coking. However, all these catalysts
provide high conversion and high hydrogen production at a higher temperature
(>450 °C). Therefore, their integration with the membrane is challenging as such a
temperature membrane may develop the leaks at the joints (particularly the ceramic
supported membranes). Further, in the case of methanol steam reforming various
support and metal combinations are tested. AZZ support and Cu metal are found to
be suitable. However, they provide high CO content. A recent study shows that
Cu-Fe supported on AZZ supports provide No CO till 450 °C which looks promising. However, the performance and life of this catalyst under high pressure needs to
be tested. Further, this catalyst also provides a high hydrogen production rate only
above 300 °C. Similarly, for glycerol steam reforming Ni-based catalysts (which
have high C–C bond cleavage) supported on alumina or ceria-zirconia support are
preferred. However, these catalysts also performed well at a higher temperature and
both CO and CH 4 contents are observed in the reformate which is not desirable.
Therefore, most of the available catalysts are not suitable for the membrane reformer
application. Hence, there is an urgent need to develop a low temperature and high
hydrogen-selective catalyst to achieve the desired performance from the membrane
reformer.
Steam Reforming Catalysts for Membrane Reformer
temperature. The thermal decomposition of glycerol to olefins was mainly responsible for the coking which severely affects the performance and is not suitable for
membrane reformer application.
Similar to ethanol, for glycerol too hydrogen yield at low temperature is very
low. Hence, for better integration, it is desirable to develop a low-temperature catalyst that can provide acceptable hydrogen flux for membrane reformer application.
5 Summary and Future Aspects
The focus of this chapter was mainly on providing an overview of the development
of membrane reformer concerning reforming catalyst for ethanol, methanol, and
glycerol steam reforming. The membrane reformer has the potential to be commercialized for on-board/on-site production of ultra-pure hydrogen. It can provide clean
energy when integrated with PEMFC and can reduce the dependency on fossil fuel.
However, the major challenge in commercializing the membrane reformer is its low
hydrogen recovery. This is linked to the performance of membrane used for selective hydrogen separation, the catalyst which is used for hydrogen generation, and
the way these two are integrated into a single assembly. Hence, it is required to
improve all these aspects to make on-board/on-site generation of hydrogen through
MR a reality. Here, I have discussed the reforming catalysts for different alcohols
which compete with each other based on application. The chapter highlights the
different catalysts used or tested for ethanol, methanol, and glycerol steam reforming and their suitability for membrane reformer application. Though several catalysts are available for ethanol steam reforming, mostly ceria-supported catalysts are
preferred as they provide low CO selectivity. Ni, Co along with some noble metal
like Ru, Rh are preferred as they reduce the coking. However, all these catalysts
provide high conversion and high hydrogen production at a higher temperature
(>450 °C). Therefore, their integration with the membrane is challenging as such a
temperature membrane may develop the leaks at the joints (particularly the ceramic
supported membranes). Further, in the case of methanol steam reforming various
support and metal combinations are tested. AZZ support and Cu metal are found to
be suitable. However, they provide high CO content. A recent study shows that
Cu-Fe supported on AZZ supports provide No CO till 450 °C which looks promising. However, the performance and life of this catalyst under high pressure needs to
be tested. Further, this catalyst also provides a high hydrogen production rate only
above 300 °C. Similarly, for glycerol steam reforming Ni-based catalysts (which
have high C–C bond cleavage) supported on alumina or ceria-zirconia support are
preferred. However, these catalysts also performed well at a higher temperature and
both CO and CH 4 contents are observed in the reformate which is not desirable.
Therefore, most of the available catalysts are not suitable for the membrane reformer
application. Hence, there is an urgent need to develop a low temperature and high
hydrogen-selective catalyst to achieve the desired performance from the membrane
reformer.
Steam Reforming Catalysts for Membrane Reformer