This work package covers the development of a desulphurization module to be integrated into the prototype hydrogen generator upstream of the reformer module. Thereby a significant reduction of the sulphur level of the liquid feedstock prior to catalytic conversion will be achieved. A desulphurized fuel with a content of £ 1-1.5 ppmw S is expected for the case of conventional diesel and biodiesel. Based on the promising results of the previous NEMESIS project3 liquid adsorption via utilization of a specific grade high-surface area activated carbon will be investigated in more detail. A prototype desulphurization module for continuous operation, ready to be connected with the prototype hydrogen generator will be developed. During the first project period, experiments on a basic-level will be performed to evaluate desulphurization capacity under different formulations of the chosen sorbent (e.g. powder form, pellets of different sizes, coated on monolithic honeycombs) and investigate different ways for sorbent regeneration according to the possibilities that have already been described. As soon as the aforementioned operating parameters are chosen, a modular pilot-scale unit will be constructed and extensively tested. The pilot-scale unit will be able to operate continuously and its main part will be divided into two switching modules; one performing diesel desulphurization while the other will be regenerated. An additional module for the cleaning of the spent regeneration medium and its recycling into the system will also be incorporated. Based on these tests a prototype desulphurization unit capable of producing about 20 litres per hour of deeply desulphurized diesel which is needed to produce 50 Nm3 H2 per hour will be designed and manufactured. Before integration into the prototype in WP6 the performance of the desulphurization module will undergo extensive testing in stand-alone mode.
Description of work
The work in WP3 is broken down into 2 tasks:
3.1 Investigation of desulphurisation by liquid phase adsorption (APTL, HYG, m01 – m18)
- Preliminary investigation on efficient sorbent formulation and sorbent regeneration strategies (APTL)
- Basic-level experiments to determine desulphurization capacity of the activated carbon sorbent for each fuel (according to the output of WP1/Task 1.2)
- Basic-level experiments on sorbent regeneration capability using organic solvents (as in the NEMESIS project) or alternative ways (e.g. thermal treatment with a simultaneous inert gas flow) and evaluation against each other.
- Quick screening multi-cyclic adsorption/regeneration experiments to investigate potential degradation/notable loss of performance of the material. These experiments will provide a strong indication on the frequency of potential adsorbent replacement.
- Identification of the most suitable formulation of the sorbent (i.e. pellets, powder form, coated on small monoliths, etc.). The goal will be to retain maximum sulphur adsorption capacity while pressure drop will be maintained at acceptable levels.
- Detailed investigation of adsorption/regeneration with a pilot-scale unit under continuous mode of operation (APTL)
- Design and build-up of a pilot-scale unit with cyclic switching between adsorption and regeneration
- Evaluation of sorbent capacity and break-through performance
- Evaluation of system reliability with emphasis on its capability to repeatedly process a specific flow rate of liquid fuel and deliver an output with total sulphur content that will be below the target value of 1-1.5 ppmw. Analysis will be performed ex-situ by sampling of processed fuel downstream of the unit.
- Extensive testing of the chosen regeneration strategy.
- Long-term cyclic operation (100 hours) to evaluate the system performance/reliability under realistic operation.
- Evaluation of liquid phase adsorption against all requirements having been identified in WP1 – such as quality of desulphurized liquid feedstock, effect of fuel nature to the desulphurization performance achieved, impact on process efficiency by integration into the prototype and impact on overall cost (APTL, HYG)
3.2 Development and construction of prototype desulphurisation module (APTL, HYG, m19 – m27)
- Fabrication of the full-scale desulphurization module (APTL, HYG)
- Specification of integration / compatibility issues with the reformer module
- Design and construction of the unit by APTL with support from HYG
- Manufacturing of desulphurization module
- Performance check of desulphurization module, covering all the aforementioned operation parameters as described in the case of the pilot-scale unit and the ones that are required by the reformer module specifications (APTL)
- Shipment to HYG (APTL)