Global Change Abstracts The Swiss Contribution - SCNAT

196 Global Change Abstracts – The Swiss Contribution | Mitigation and Adaptation Technologies
identify improvements on the basis of accelerated
combustion caused by the hydrogen as well as the
reduced gas exchange losses due to EGR and associated
less required throttling for a given engine
output. The best combinations of EGR rate, hydrogen-fraction
in the fuel and ST exhibited optimal
in- cylinder pressure characteristics accompanied
by moderate combustion peak temperatures and
low expansion cylinder temperatures. (c) 2007 International
Association for Hydrogen Energy.
International Journal of Hydrogen Energy, 2007,
V32, N14, SI, SEP, pp 3073-3083.
08.1-418
Multi-regional long-term electricity supply
scenarios with fusion
Gnansounou E, Bednyagin D
Switzerland
Energy & Fuels , Engineering
This paper examines the global potential for deployment
of fusion power through elaboration
of multi-regional long-term electricity market
scenarios for the time horizon 2100. The probabilistic
simulation dynamic programming model
PLANELEC-Pro was applied in order to determine
the expansion plans of the power generation systems
in different world regions that adequately
meet the projected electricity demand at minimum
cost given the quality-of-service and CO 2
emissions constraints. It was found that the deployment
of total 330 - 950 GWe of fusion power
world-wide could allow for reducing 1.8 - 4.3 % of
global CO 2 emissions from electricity generation,
while entailing a slight increase of levelized system
electricity cost (by approx. 0.1 - 0.4 is an element
of(cents)/ kWh). By the end of century, the
estimated share of fusion in regional electricity
mixes varies from 1.5 to 23% depending on the
region. It is concluded that economic analysis of
fusion technology should be complemented with
the evaluation of the whole fusion RTD program
in terms of social rate of return taking into account
its external “spillover” benefits.
Fusion Science and Technology, 2007, V52, N3,
OCT, pp 388-392.
08.1-419
Carbothermal reduction of alumina: Thermochemical
equilibrium calculations and
experimental investigation
Halmann M, Frei A, Steinfeld A
Israel, Switzerland
Engineering , Energy & Fuels
The production of aluminum by the electrolytic
Hall-Heroult process suffers from high energy
requirements, the release of perfluorocarbons,
and vast greenhouse gas emissions. The alternative
carbothermic reduction of alumina, while
significantly less energy- intensive, is complicated
by the formation of aluminum carbide and oxycarbides.
In the present work, the formation of Al,
as well as Al 2OC, Al 4O 4C, and Al 4C 3 was proven by
experiments on mixtures of Al 2O 3 and activated
carbon in an Ar atmosphere submitted to heat
pulses by an induction furnace. Thermochemical
equilibrium calculations indicate that the
Al 2O 3-reduction using carbon as reducing agent is
favored in the presence of limited amounts of oxygen.
The temperature threshold for the onset of
aluminum production is lowered, the formation
of Al 4C 3 is decreased, and the yield of aluminum
is improved. Significant further enhancement in
the carbothermic reduction of Al 2O 3 is predicted
by using CH 4 as the reducing agent, again in the
presence of limited amounts of oxygen. In this
case, an important by-product is syngas, with a
H-2/CO molar ratio of about 2, suitable for methanol
or Fischer-Tropsch syntheses. Under appropriate
temperature and stoichiometry of reactants,
the process can be designed to be thermo-neutral.
Using alumina, methane, and oxygen as reagents,
the co-production of aluminum with syngas, to
be converted to methanol, predicts fuel savings of
about 68% and CO 2 emission avoidance of about
91%, vis-A-vis the conventional production of Al
by electrolysis and of methanol by steam reforming
of CH 4. When using carbon (such as coke or
petcoke) as reducing agent, fuel savings of 66%
and CO 2 emission avoidance of 15% are predicted.
Preliminary evaluation for the proposed process
indicates favorable economics, and the required
high temperatures process heat is readily attainable
using concentrated solar energy.
Energy, 2007, V32, N12, DEC, pp 2420-2427.
08.1-420
Secondarv effects of catalytic diesel particulate
filters: Copper- induced formation of
PCDD/Fs
Heeb N V, Zennegg M, Gujer E, Honegger P, Zeyer
K, Gfeller U, Wichser A, Kohler M, Schmid P,
Emmenegger L, Ulrich A, Wenger D, Petermann J L,
Czerwinski J, Mosimann T, Kasper M, Mayer A
Switzerland
Engineering, Meteorology & Atmospheric Sciences,
Human & Public Health
Potential risks of a secondary formation of polychlorinated
dibenzodioxins/furans (PCDD/Fs) were
assessed for two cordierite- based, wall-through
diesel particulate filters (DPFs) for which soot
combustion was either catalyzed with an iron- or
a copper-based fuel additive. A heavy duty diesel