Skip to main content

New Methods for Superior Integrated Hydrogen Generation System

Final Report Summary - NEMESIS (New Methods for Superior Integrated Hydrogen Generation System)

The scientific and technological objective of NEMESIS project was to develop a small-scale, fuel flexible hydrogen generator that is capable of working with liquid and gaseous hydrocarbon free stock. A small scale on-site hydrogen generator for decentralised applications was extended to a wider range of fuels and updated by introducing advanced separation technologies, new innovative materials and cost-effective and highly efficient sub-components. The project application led to an integrated modular design, as a result of an optimised system layout and of the balance of plant analysis.

The hydrogen generation unit comprises of three modules, namely the fuel preparation module (FPM), the hydrogen generation module (HGM) and the hydrogen conditioning module (HCM). The developed prototype was able of producing 10 kg H2 per day, and was used as a basis for an up-scaling strategy for fuelling up to 100 vehicles per day and for the integration of the generation into existing fuel stations infrastructure.

During the first project phase the targets and tasks of the project were translated into functional requirements while a steady-state simulation with no inclusion of losses was carried out. The influence of various operating parameters was examined and the modules were integrated to an overall system, which was evaluated for its efficiency. Evaluation results formed the basis for further process concepts decisions. Alternatives for all three modules were extensively examined and decisions regarding further development were made.

Following the completion of the first project phase, work was concentrated on realising the proposed concept within the prototype unit. Steady-state simulation included losses, and evaluation of the project components had taken place in regard to the overall system efficiency and potential for internal heat management. All three modules were extensively studied, regarding the materials employed, the obtained performances, the limiting conditions and the probable ambiguities, and their design was updated accordingly. Economic evaluation was started by identifying appropriate alternatives for hydrogen and off-gas storage without changing the view of an existing petrol station.

The main goal for the final phase of the project was to realise the prototype unit and test it on natural gas as well as on diesel feedstock for at least three months. A final process flow diagram was developed after pre-testing of the fuel preparation module and resulted in an adjustment of the operation strategy. The FPM underwent three test series, resulting in the selection of the operational temperatures and, after the integration of the desulphurisation unit, FPM was incorporated to the overall system. The pre-reformer catalyst was evaluated on laboratory scale, while experiments were carried out for the development of the material selected for gas-phase desulphurisation. The final design of the HGM was decided based on all available test results. HCM was developed through construction and testing on the prototype scale; however, some limitations arose from leakage of the tubing system incorporated within the unit. Regarding the outside facilities for prototype testing, a first test series was performed on natural gas with the HGM and HCM. Thereafter the complete system was tested successfully on low sulphur diesel. System performance was evaluated against the technical targets for the prototype unit that were set at the project beginning. Finally, economic evaluation was completed, and a cost model was set up to calculate the revenue of the investment for a commercial system of the proposed technology and to identify an appropriate funding scheme.

The constructed prototype was able of producing 5 Nm3/h of hydrogen. The modules forming the whole system were:
1. pre-reformer operating at 800 degrees Celsius and gas-phase desulphurisation unit (FPM);
2. reformer with integrated off-gas burner operating at 800 degrees Celsius, no shift stage (HGM) and
3. single layer pressure swing adsorption unit (HCM).

A membrane separation unit for hydrogen purification was also prepared and tested separately from the overall system.
%NEMESIS results achieved after completion of the research and tests, both for the various components and the overall system, could be summarised as follows:
1. components of the prototype unit have been developed, constructed, tested and performed satisfactorily. However a method for disposal or recycling of the organic solvent of desulphurisation was yet to be defined.
2. the unit was tested for more than 200 hours on natural gas and low sulphur diesel and testing results were evaluated.
3. the developed steady-state model was verified successfully with prototype tests results by adaptation of the process parameters.
4. economic evaluation proved that, in order to implement the technology on existing petrol stations with minimal impact on the station view, both investment level in the start-up phase and fixed cost level were too high, thus grants are necessary to bring this technology into the market.

Related documents