The_Catalyst_Review_August_2023 - 9

SPECIAL FEATURE
SEG of MSW
could reduce the
reliance on fossil
fuels of, and the
cost of CO2
supply
to, various sectors
of our economy.
Table 2. Summary of levelised cost of hydrogen for different technologies.15,32
Current Development Status
Although the SEG of MSW has resulted in a higher cost of hydrogen production, this technology is still in a relatively early stage
of development. Much R&D activity is focused on designing and optimizing sorption materials and reducing sorbent deactivation
during cyclic operation. However, the pilot and demonstration scale experience are scarce. At the pilot plant scale, the SEG was
performed in a dual fluidized bed unit at the Technical University Wien. The design fuel input of this pilot plant is 100 kW.
Moreover, 20 kW and 200 kW pilot plants were developed and tested at the Institute of Combustion and Power plant Technology
of the University of Stuttgart. Finally, a 71 kW pilot plant was developed by the Gas Technology Institute (GTI) in the US. The pilotscale
experiments showed that about 70-80% volume fraction of H2
was achieved.33 This was in line with the figures reported by
Santos and Hanak.15 It is important to emphasize that, to date, no demonstration scale units have been operated for the SEG of solid
fuels. The first 1.5 MW demonstration plant is currently being developed at Cranfield University in collaboration with GTI, Doosan
Babcock and the UK Department for Business, Energy and International Strategy (BEIS).34
However, some of the existing dualfluidized-bed
gasifiers were adopted to operate under the SEG, including the 8 MW gasification plant in Güssing, Austria and the
8.5 MW gasification plant in Oberwart, Austria. As these units were not designed specifically for the sorption-enhanced process, the
maximum hydrogen purity reached 52-57%.33
Future Development Needs and Perspective
There is no simple answer to whether the SEG of MSW is a viable technology to supply LCH to support the decarbonization of our
economy. On the one hand, such a process would allow us to efficiently utilize MSW and significantly reduce the amount of MSW
ending up in landfills. It also has the capability of supplying LCH that meets the requirements of the UK's Low-Carbon Hydrogen
Strategy. Furthermore, SEG of MSW could reduce the reliance on fossil fuels of, and the cost of CO2
supply to, various sectors of
our economy. This is especially critical considering the current supply crisis associated with soaring prices of natural gas. Notably,
if all MSW generated in the UK (7.2 million tpa) was processed in SEG, it could supply about 35% (0.25 million tpa) of current UK
H2
transport. However, as with other carbon capture technologies, the challenge is a
production (0.7 million tpa).35 Therefore, SEG of MSW can play a crucial role in the decarbonization of large cities and industrial
clusters, reducing the need for MSW and H2
high economic penalty. A higher energy requirement and capital cost of the SEG process than that of the conventional gasification
process results in an uncompetitive LCOH.
Notably, SEG is currently at a relatively early stage of development, with the technology readiness level assessed to be about 3-5.
The mature hydrogen production technologies, such as steam methane reforming, coal gasification or electrolysis, have already
reached commercialization deployment and are well established. This is equivalent to the technology readiness level of 9. Therefore,
further development of the sorption-enhanced processes and new sorbents with better cycling performance can bring further cost
reductions.
This, combined with policy and subsidy support from the government and the development of carbon markets, can make the SEG of
MSW competitive with well-established processes.
continued on page 15
The Catalyst Review
August 2023
9

The_Catalyst_Review_August_2023

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