Abstract
Keywords - Hydrogen, Alternative Fuel, Steam Methane Reformer, esH2, CUTE
Abstract - EMT (Empresa Municipal de Transportes), the public bus fleet operator in
Madrid demonstrates since spring 2003 the operation of three Mercedes FC buses in the frame of the European project CUTE as well as a Iveco FC bus.
A team, named esH2 (with the trade mark) was set up by the companies Air Liquide España, Gas Natural SDG and Repsol YPF to design and to build the hydrogen station where the FC-buses are refuelled.
On-site hydrogen production through natural gas steam reforming, a well-known process largely used in big plants, was considered to be the best option to provide hydrogen to the filling station. This technology allows benefiting from the natural gas network availability.
The challenge was to make the process compact enough to fit in a filling station. A full automation of the process was also necessary to make it of friendly operation.
In esH2 group, Air Liquide is responsible for the global project and specifically for hydrogen storage and compression while Gas Natural SDG and Repsol YPF are responsible for the on-site hydrogen production.
Steady hydrogen production to respond to the demand from all buses is around 75 Nm 3 /h.
Selected capacity for the on-site steam reformer was only 50 Nm 3 /h, a figure below the maximum demand ; the decision obeyed to the following criteria:
- enough capacity to provide valuable results from the demonstration
- more time running at full capacity
- frequent start-and-stops avoided when not all the buses are on service
- lower investment cost
Supplementary and back-up hydrogen is road trucked to the station by Air Liquide., what guarantees the availability of hydrogen to fulfil at any moment the demand of all FC buses when operating simultaneously.
There is a common hydrogen storage at 200 bar either for hydrogen produced in the methane steam reformer and for trucked hydrogen. A high capacity compressor takes the hydrogen from this storage and feeds the dispenser where the tanks on the buses are filled at 350 bar.
The paper describes in detail the technical solutions adopted in Madrid and the results of one year operation. This can help others to adopt their solutions for coming hydrogen stations still for demo projects.