Nuclear Energy Options for Hydrogen and Hydrogen-Based Liquid Fuels Production
Name
NES-001.pdf
Description
NES-001.pdf
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813.49 KB
Format
Adobe PDF
Checksum (MD5)
dd2e06aadebdcd30c0525684c7d5157c
Author(s)
Yildiz, Bilge
Kazimi, Mujid S.
Date Issued
September 2003
Publisher
Massachusetts Institute of Technology. Center for Advanced Nuclear Energy Systems. Nuclear Energy and Sustainability Program
Series/Report no.
MIT-NES;TR-001
Abstract
Nuclear energy can be used for hydrogen production through thermochemical or
electrochemical processes for splitting water (and/or steam) into its elemental parts. The
overall performance of alternative routes for using nuclear energy to supply the needed heat
or electricity depends on the operating temperature, efficiency of the processes involved,
complexity of the systems used and capital costs of the nuclear and hydrogen technologies.
In this work, we assess the economics of possible technologies to produce hydrogen using
nuclear energy. The purpose of this assessment is to identify the most attractive options for
further research and development and eventual application to nuclear hydrogen production.
Both thermochemical processes and electrolysis require high temperatures for good
efficiency. Thus, hydrogen production is best accomplished using advanced reactors that are
capable of reaching much higher temperatures than today's LWRs. At temperatures above
700 [degrees]C, the options range from using steam methane reforming in the short term to the much more involved chemical cycles or steam electrolysis in the long term. The helium cooled
graphite moderated reactors operating at temperatures above 850 [degrees]C have often been
proposed for such purposes. However, we find the high temperature steam electrolysis
process coupled to a supercritical CO[subscript 2] gas turbine cycle, possibly in a direct cycle
Supercritical Advanced Gas Reactor, as more promising than other technology options. At
650 to 750[degrees]C of reactor outlet/turbine inlet/process temperatures, this technology can achieve 52 to 56% overall efficiency in converting nuclear thermal energy into energy content of
hydrogen, respectively.
In this work, we also evaluate the technical and economical viability of liquid fuel
synthesis using nuclear hydrogen. The liquid fuel can be used in the existing mature
infrastructure for transportation and combustion of liquid fuels before large scale hydrogen
infrastructure becomes widely established. We propose that CO2 captured from coal plant
emissions and nuclear hydrogen be the feedstock to the synthesis process. The cost of this
approach would be independent of the natural gas feedstock and may prove market
competitive in the near future.
Considering the production cost of hydrogen, the thermochemical Sulfur-Iodide cycle
coupled to the helium cooled Modular High temperature Reactor (MHR) is found to be also
attractive at temperatures above 850 [degrees]C, based on the plant cost and the process efficiency estimates by the designer company. In our work, the cost of production is estimated to fall between $1.13 and 2.37/kg-H2. This range reflects the uncertainties about the operating
conditions and cost of the technology in the future.
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