figure-performance-cells-32.html
Procedings
33 / 88
e n e r g y + p r o c e e d i n g s 31 figure 10, the
power
curve combined with average fu for the four stacks is presented. page 39 of 122 figure 9 illustrates the status of another route to the improvement of the cathode performance. here, a nano-crystalline gadolinia-doped ceria catalyst has been added to the electrodes, resulting in improved performance over the comparable reference cells for both lsm/ysz and lsc/cgo electrodes [7]. continued development includes investigation of stability of the colloidal impregnated nano-particles as a function of time and temperature.
fuel
processing and
system
development at tofc tofc has previously studied a range of
fuel
s including natural gas, lpg, methanol, dme, diesel and ammonia as sofc
fuel
s as mentioned above. the studies predict
system
electrical efficiencies in the range of 40-56% (ac out/lhv
fuel
in), depending on the
fuel
used and the size of the
system
. the range of
fuel
s have now been extended to include ethanol and coal syngas [8] by the development of a coke resistant ethanol reforming/methanation catalyst and leveraging the catalyst know- how of htas involved in high-temperature methanation of coal gas, respectively. tofc has collaborated with wärtsilä since 2002 on the development of sofc
system
s primarily for distributed
power
generation and marine application. since late 2004, wärtsilä has operated the sofc test
system
with planar sofc stacks developed and manufactured by tofc. during spring 2006 four stacks were installed, each having a nominal
power
of 1 kw. the
system
was in continuous operation providing an average
power
of 3.6 kw at 55-60%
fuel
utilisation (fu), this being a valid reference point for further
system
development and up-scaling. the in total 4000 hours of operation indicated a very good reliability and low degradation rates of the applied stack and
system
technologies. in figure 10, the
power
curve combined with average fu for the four stacks is presented. figure 10. average stack voltage (upper curve) and current (lower curve) of 75-cell stacks in a four- stack
system
. 0 10 20 30 40 50 60 70 80 90 50 550 1050 1550 2050 2550 3050 running hours voltage [v] and current [a] average stack voltage average stack current figure.10..average.stack.voltage.(upper.curve).and.current.(lower. curve).of.75-cell.stacks.in.a.four-stack.
system
. a complete 20 kw demonstration unit based on pre- reforming of natural gas with anode recycle has been operated for more than 1,000 hours with 24 stacks of the 75-cell (12x12 cm 2 ) type. another 24-stack prototype, now based on methanol as the
fuel
, is also under construction by wärtsilä. the methanol is methanated upstream the anode, using a proprietary haldor topsoe catalyst. for smaller capacities it is of paramount importance to have a very tight integra- tion both mechanically and thermally of all the hot components of the sofc
system
. therefore, tofc has initiated a program to develop a so-called pow- ercore unit comprising
fuel
processing, the stack, feed-effluent heat exchangers and catalytic burner(s). a complete 5 kw
power
core unit based on methanol has been constructed and tested successfully under dynamic load following operating conditions. in similar
system
s, based on diesel
fuel
, strategies to counteract the impact of sulphur are under investiga- tion. furthermore, dynamic
system
modelling tools have been included in the tofc design concept. market and technology demonstration tofc is pursuing three market segments; micro combined heat and
power
(micro chp, 1-5 kw), auxiliary
power
units for the transportation segment (3-10 kw) and distributed generation (20-500 kw). these markets are all transitioning from the develop- ment phase into the test and demonstration phase. this calls for a markedly increased number of stacks for development, testing, and demonstration. to meet this growing demand, tofc is constructing a new cell and stack production facility with an annual capacity of 5 mw. the facility is financially supported by eu’s life environment programme. the facility comprises all unit operations, from ceramic powder processing to assembly of final stacks. the proc- esses are based on up-scaling of existing, well-known methods, which are already widely used industrially. the plant will be located together with tofc’s of- fices and research laboratories in kgs. lyngby, den- mark, thus ensuring short communication paths and feedback from production to development. start-up is scheduled to late 2008. two danish projects in the pso program supported by the danish utilities have been initiated. one is aiming at demonstrating a 1 kwe micro-chp unit and the other is a 10 kwe stack demonstration facility in- cluding
fuel
processing and
power
conversion located at a
power
station in copenhagen, denmark. future perspectives for
fuel
cells in connec- tion with energy sources, energy carriers and energy technology as described above the high-temperature
fuel
cells and possibly especially the sofc present a better environmental option versus existing fossil
fuel
tech- nologies. these
fuel
cells run on natural gas or syn- gas which is reformed directly within the cell which renders the conversion process highly efficient. when
sofc-fuel-soec-34.html
