New Method for Superior Integrated Hydrogen Generation System 2+
Key objectives of the project
The overall objective of the NEMESIS2+ project is the development of a small-scale hydrogen generation prototype capable of producing 50 mN3 per hour from diesel and biodiesel at refuelling stations. An increase of reliability and efficiency of the hydrogen generation system and a reduction of hydrogen production costs will be the major goals. Special emphasis will be placed on liquid desulphurisation prior to the catalytic conversion step. This will be supplemented by the development of sulphur-tolerant reforming and water gas shift catalysts. By applying pressurized steam reforming with subsequent water gas shift and a pressure swing adsorption units a hydrogen purity of 5.0 (99,999 %) will be achieved. In order to be able to run on liquid fuels as well as on off-gas from the hydrogen purification unit, a dedicated dual fuel burner will be developed. Work will be completed by a techno-economic evaluation of the prototype hydrogen generation system.
Catalyst poisoning arising from sulphur being present in liquid fuels is one of the most apparent challenges. In order to overcome this obstacle NEMESIS2+ uses an innovative approach based on liquid desulphurisation by adsorption. As a back-up solution sulphur tolerant reforming and water gas shift catalysts will be developed. Another risk arising from the use of liquid fuels is catalyst deactivation by coke or gum formation. Therefore the applicability of a low temperature coke precursor removal zone prior to the main reaction zone will be tested by adding small amounts of air.
In order to reduce hydrogen production costs and increase efficiency and reliability of the system the NEMESIS2+ project will focus on liquid fuels only. Fossil diesel, renewable biodiesel and sulphur free GtL diesel will be considered for hydrogen production. Based on the promising results from the previous NEMESIS project a liquid desulphurisation module for continuous operation will be built and tested upstream the catalytic conversion step. In order to reduce costs the system will be scaled up from 5 mN3/h to 50 mN3/h. Additionally, an elaborated thermal heat integration system will be built up, making use of the heating value of the PSA off-gas. Increasing the system pressure from 6 to 12 bars will reduce system size significantly, thus further reducing investment costs. Optimum operating conditions for steam reforming of diesel and biodiesel will be mapped during 1000 hour long-term testing of the hydrogen generator prototype.
Expected socio and economic impact
Within the call FCH-JU-2010-1 NEMESIS 2+ addresses the application area SP1-JTI-FCH.2 “Hydrogen Production & Distribution” which aims at developing a portfolio of sustainable hydrogen production, storage and distribution processes which can meet 10 % – 20 % of the hydrogen demand for energy applications from carbon-free or lean sources by 2015. NEMESIS 2+ will contribute to reach this target by demonstrating sustainable hydrogen production from conventional and alternative liquid fuels. The NEMESIS 2+ on-site hydrogen generator will speed-up the roll-out of the needed hydrogen infrastructure for fuel cell cars as described in the FCH JU Annual Implementation plan 2010, in which the market introduction of hydrogen powered cars is expected in 2015. The implementation plan envisions a market share between 10 and 20 % of sustainably produced hydrogen. The NEMESIS 2+ system will contribute to reach this target by developing a pre-commercial and sustainable on-site hydrogen generator system.