Muradov Investigates Environmentally Friendly Production of Hydrogen
Dr.
Nazim Muradov of the Hydrogen R&D Division of the Florida Solar
Energ
y Center® (FSEC®) is working
on a novel approach to solving the energy and environmental problems
associated with producing hydrogen from fossil fuels. He’s
working with other FSEC researchers on the technical and economic
feasibility of large-scale production of hydrogen and carbon by
the catalytic dissociation of natural gas.
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credit: Steven C. Spencer, FSEC |
This concept offers an environmentally friendly way to produce
hydrogen. Most of the industrial hydrogen production today is
based on the steam methane reforming process, a source of significant
CO2 emissions into the atmosphere
(about 10 tons of CO2 per ton of
hydrogen produced). Muradov points out, “It’s felt
by many energy experts that the huge quantities of CO2
emissions that come from using fossil fuels to produce hydrogen
might potentially diminish the environmental appeal of hydrogen
as an ecologically clean fuel.”
Carbon dioxide sequestration (underground or under the ocean)
is being actively discussed in the literature as a possible solution
to this environmental problem. However, many experts have expressed
concerns regarding the unpredictable and potentially catastrophic
ecological consequences of this approach. Muradov’s work
is aimed at eliminating the production of CO2
rather than worry about getting rid of it after the hydrogen has
been produced. That’s why he has been studying the CO2-free
production of hydrogen and carbon via thermal decomposition (or
cracking) of methane.
Several important technical issues still need to be addressed
before the large-scale implementation of this technology would
be possible. Muradov pointed out that the most serious problem
is how to arrange a continuous and sustainable process for methane
decomposition with incessant withdrawal of carbon from the reactor.
“The root of the problem lies in the fact that carbon product
tends to accumulate on the catalyst surface gradually deactivating
it,” he explained, “and as a result, it decreases
the yield of hydrogen.” Muradov and other FSEC researchers
have come up with an original solution to this problem by turning
this apparent technical obstacle to their advantage. They have
discovered that at certain operational conditions, carbon itself
becomes a catalyst for the process. This eliminates the use of
expensive metal-based catalysts and significantly simplifies the
process. The FSEC researchers have been awarded a U.S. Patent
(No. 6,670,058 B2) for the development of the thermocatalytic
process for CO2-free production
of hydrogen and carbon from hydrocarbons.
Techno-economic evaluation of the catalytic methane decomposition
process revealed the sensitivity of hydrogen production cost to
the selling price of carbon product. Comparative economic assessment
indicates that the FSEC-developed process becomes competitive
with steam methane reforming process (currently the lowest cost
option for hydrogen production) at a carbon selling price of $100-300/ton
(depending on the economic assumptions). The carbon produced in
the carbon-catalyzed methane decomposition process is a pure (sulfur-
and ash-free) product that could be marketed at a selling price
of $300/ton or more for production of electrodes and composite
materials.
FSEC researchers have recently found a way to produce particularly
valuable filamentous form of carbon (graphitic nano-fibers) by
decomposition of methane. This shows that FSEC’s technology
could be economically competitive with the conventional hydrogen
production processes and, at the same time, it offers significant
environmental advantages over existing technologies. This work
is currently funded by NASA, which is interested in the development
of an environmentally friendly technology for the hydrogen production
at the NASA-KSC site for Space Shuttle program.
The near- to medium-term future for hydrogen production will almost
certainly continue to rely on fossil fuels, particularly natural
gas. However, from both environmental and economic perspectives,
it makes more sense to produce hydrogen by the catalytic dissociation
of natural gas instead of the steam methane reforming coupled
with CO2 sequestration, which is
associated with some ecological uncertainties. FSEC-developed
technology on direct cracking of methane could be based on existing
natural gas infrastructure that would minimize the cost of converting
to the hydrogen economy. This could also facilitate a smooth transition
from the current hydrocarbon-based economy to the ultimate hydrogen-from-renewables
economy of the future.