Overview of the Results: A 50kWe fuel cell CHP prototype system has been built at GE’s facilities in Rugby UK. Despite pre-commissioning of the Hydrogen Production System in Greece prior to delivery to the prototype test site, the integrated AutoRE system did not complete the planned 3000hr test due to early corrosion failure of the reformer combustion tubes. The presence of corrosion products in the combustion tubes caused the pressure drop to become too high, preventing the use of the Pressure Swing Absorption (PSA) systems tail gas in the combustion cycle. This significantly reduced the efficiency of the unit as only Natural gas was present as the combustion fuel and the tail gas produced by the PSA was effectively wasted. The electrical efficiency of the system was resultingly drastically reduced by this issue, with an efficiency of 5.8% at 53% capacity and 11.5% at 100% capacity. This compares to an expected efficiency with tail gas utilization of 36% at 53% capacity and 32.5% at 100%.
In addition to the testing of the 50kWe prototype system described above, lab-scale testing of component enhancements to the prototype system, to reduce its cost of electricity/foot-print and increase its performance has been carried out. Testing of selective membranes at SINTEF (to replace the Pressure Swing Absorber unit to produce high purity H2) with increased system efficiency has been completed. Compared to the baseline configuration, cooling and dehydration of the reformed natural gas feed before the H2 purification step are not required.
The final lab-scale testing carried out is that of short stack PEM fuel cell units at different operating conditions. Results obtained showed that upon switching from high purity hydrogen to a H2/CO2 mixture the fuel cell performance was highly affected. Increasing the proportion of CO2 reduced the performance of the fuel cell, although this performance was fully recovered when pure hydrogen fuel was re-introduced. A potential solution to CO poising could be injection of air (air bleeding) together with the reformate gas.
In parallel with the above test programmes, extensive modelling of the fuel cell based CHP system had been carried out, both for the baseline configuration and including future design improvements such as replacement of the Pressure Swing Absorber with a membrane-based separation system.
The results show that increasing the nominal power of the fuel cell has a positive impact on plant performance. However, careful economic evaluation is needed to analyze possible cost increases. The thermal integration of the reformer improves the plant performance without any drawbacks and should be adopted. Selective membranes integrated in the reactors (and not used as a standalone purification unit) allow significant efficiency improvements and plant complexity reduction, in particular if the membranes are integrated in the reforming side of the reformer reactor. Performance of a trigeneration plant (CHCP) based on the AutoRe cogeneration (CHP) unit on real energy management scenarios has been studied, together with the impact of two innovative technical solutions: (1) the advanced fuel processor designs, and (2) of thermally driven cooling machine has been assessed.
Additional modelling has also been undertaken to look at fuel cell degradation. This latter modelling activity has leveraged on the results of a previous project (SAPPHIRE) which also targeted a CHP fuel cell system. Fuel cell degradation mechanisms have been identified and described and some mitigation and diagnostic techniques have been proposed.
Exploitation: the focus of the exploitation of AutoRE results in the near term is to pursue a component exploitation strategy rather than a fully integrated CHP product. The particular components to be exploited are the natural gas reformer, the auto-derivative fuel cell and the membrane hydrogen separator. In addition, general project results and findings will be exploited through follow-on development/ project work together with dissemination to the public domain for exploitation by third parties.
Dissemination: The AutoRE project website, which is fully accessible to the general public, has been updated with relevant project information. This includes downloadable copies of the AutoRE public domain deliverables, together with links to AutoRE scientific publications. The website
https://www.autore-eu.com(se abrirá en una nueva ventana) forms the main repository of information for the AutoRE project.
The total number of scientific publications for the AutoRE project is 24 and includes both peer reviewed scientific publications where open source links to the documents are provided, together with presentations given at workshops and conferences.
Further publications are planned after the completion of the AutoRE project, particularly as part of the final project workshop, with the proposed venue being the European Fuel Cell Conference (EFC19), to be held in Naples in December 2019 (
http://www.europeanfuelcell.it/(se abrirá en una nueva ventana)).
