This study introduces an evaluation of the downstream utilization of oxygen produced by
the hybrid sulfur process (HYS). Both technical and economic aspects were considered
in the production of primarily synthesis gas and hydrogen. Both products could increase
the economic potential of the hybrid sulfur process.
Based on an assumed 500MWt pebble bed modular nuclear reactor, the volume of
hydrogen and oxygen produced by the scaled down HYS was found to be 121 and 959
ton per day respectively.
The partial oxidation plant (POX) could produce approximately 1840 ton synthesis gas
per day based on the oxygen obtained from the HYS. The capital cost of the POX plant
is in the order of $104 million (US dollars, Base year 2008). Compared to the capital cost
of the HYS, this seems to be a relatively small additional investment. The production
cost varied from a best case scenario $9.21 to a worst case scenario of $19.36 per GJ
synthesis gas. The profitability analysis conducted showed favourable results, indicating
that under the assumed conditions, and with 20 years of operation, a NPV of $87 mil. and
an IRR of 19.5% could be obtained, for the assumed base case. The economic sensitivity
analysis conducted, provided insight into the upper and lower limitations of favourable
operation.
The second product that could be produced was hydrogen. With the addition of a water
gas shift and a pressure swing adsorption process to the POX, it was found that an
additional 221 ton of hydrogen per day could be produced. The hydrogen could be
produced in the best case at $2.34/kg and in the worst case at $3.76/kg. The investment
required would be in the order of $50 million. The profitability analysis for the base case
analysis predicts an NPV of $206 million and a high IRR of 23.0% under the assumed
conditions. On financial grounds it therefore seemed that the hydrogen production
process was favourable.
The thermal efficiency of the synthesis gas production section was calculated and was in
good agreement with that obtained from literature. The hydrogen production section’s
thermal efficiency was compared to that of steam methane reforming of natural gas
(SMR) and it was found that the efficiencies were comparable but the SMR process was
superior.
The hydrogen production capacity of the HYS process was increased by a factor of 1.83.
This implied that for every 1 kg of hydrogen produced by the HYS an additional 1.83 kg
was produced by the proposed process addition. This lowers the cost of hydrogen
produced by the HYS from $6.83 to the range of approximately $3.93 - $4.85/kg.
In the event of a global hydrogen economy, traditional production methods could very
well be supplemented with new and innovative methods. The integration of the wellknown
methods incorporated with the new nuclear based methods of hydrogen
production and chemical synthesis could facilitate the smooth transition from fossil fuel
based to environmentally friendly methods. This study presents one possible integration
method of nuclear based hydrogen production and conventional processing methods.
This process is technically possible, efficient and economically feasible. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2009.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/4000 |
| Date | January 2009 |
| Creators | Conradie, Frederik Hendrik |
| Publisher | North-West University |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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