FUEL CELLS USING MOLTEN CARBONATES HOLD OUT GREAT PROMISE FOR ELECTRICITY PRODUCTION. IF THEY ARE TO PROVE A TECHNICAL SUCCESS, HOWEVER, MAJOR PROBLEMS HAVE TO BE OVERCOME, WHICH REQUIRES R&D WORK.
THE AIM OF THIS PROJECT IS TO DEVELOP NEW COMPONENTS THAT ENABLE TWO OF THE MAIN PROBLEMS INHERENT IN THE BASIC CELL TO BE OVERCOME:
- CORROSION OF THE METALLIC COMPONENTS (CURRENT COLLECTORS AND GAS DISTRIBUTORS);
- CREEP AND POST-SINTERING IN THE ANODE DURING OPERATION.
In the first phase of the study, a literature review and preliminary short term corrosion tests in the TG apparatus were carried out on a variety of stainless steels. Our results emphasised the key role played in corrosion behaviour by the water content in the gas mixtures. Lengthy out of cell corrosion tests (duration 500 to 700 hours) were carried out on AISI 310, AISI 347 and AISI 321. All these materials were tested in humidified cathodic environments, at two different levels of utilisation, and in an exhausted fuel environment. A cell test facility was assembled. Current collectors made from AISI 316, AISI 304, AISI 321, AISI 347 and AISI 310 were tested in the cells, both at the anodic and the cathodic sides. For the final cell, a sheet of nickel was used as the anodic current collector and a sheet of AISI 310 was used as the cathodic current collector. It had a very good performance.
THE RESEARCH COMPRISES THE FOLLOWING WORK:
1.- DESIGN STUDIES OF MATERIALS FOR CURRENT COLLECTORS AND GAS DISTRIBUTORS:
PRELIMINARY TESTS ON CORROSION BY MOLTEN CARBONATES USING TGA AND POT FURNACE TECHNIQUES, VARYING THE COMPOSITION OF THE MATERIAL (VARIOUS STAINLESS AND ALLOYS), THE COMPOSITION OF THE FUEL GAS AND THE TEMPERATURE (IN THE 600-700 CELSIUS DEGREES RANGE);
IN-CELL TESTS (IN A SINGLE 20 CM TO THE POWER OF TWO AND-OR 3 CM TO THE POWER OF TWO CELL) ON MATERIALS SELECTED BY MEANS OF THE ABOVE-MENTIONED SCREENING PROCESS);
POST-TEST ANALYSES (SEM, MICROPROBE AND X-RAY DIFFRACTOMETER);
2.- STUDY OF NEW ANODE MATERIALS:
NI COATING OF ALUMINA POWDERS BY ELECTROLESS METHODS;
SHAPING AND SINTERING OF ELECTRODES USING SUCH POWDERS AND CHARACTERIZATION OF THE RESULTING COMPONENTS;
AGEING TESTS IN ATMOSPHERES SIMULATING OPERATING CONDITIONS IN THE 600-700 CELSIUS DEGREES RANGE;
IN-CELL TESTS AND POST-TEST ANALYSES;
3.- COST ASSESSMENT:
DESCRIPTION OF A MANUFACTURING METHOD FOR EACH OF THE ABOVE-MENTIONED COMPONENTS AND DETERMINATION OF THE RELEVANT PRODUCTION COSTS.