(515a) Fuel Flexible, High Efficiency Catalytic Reformer for Hydrogen Generation

Successful development of efficient fuel cell systems is highly dependent on the effectiveness and durability of reforming systems for supplying H₂ or stack-quality syngas and permitting stable, coke-free system operation.  Some of the present challenges affecting widespread deployment of fuel cell power generation solutions are sulfur poisoning, coke formation, performance durability, and water recovery.  Practical liquid fuels include distillate fuels such as military jet fuels (consisting of up to 3000 ppm_w sulfur), diesels or kerosene, as well as renewable fuels such as bio-diesels.  Making these fuels suitable for use in the fuel cell stacks requires: i) reformation of the fuels to minimize higher hydrocarbon content in the reformate to an acceptable level (depending on the fuel cell type); ii) achieving sulfur cleanup to <1 ppm_v in the reformate stream; iii) process intensification (by closely integrating steam generation, sulfur cleanup, and reforming catalyst in an ultra-compact package resulting in high gravimetric and volumetric power densities); and iv) incurring low parasitic losses by implementing off-the-shelf balance-of-plant components.  In addition to sulfur-tolerant and coke-free reformer operation, water neutrality is an essential component to the power generation systems, especially for applications in remote locations.  The ability to achieve all of the objectives above demands practical catalytic fuel reforming systems that include effective catalyst materials, robust reactor design, and optimal operating conditions.

Precision Combustion, Inc. (PCI) continues to develop and advance its integrated reformer systems that are fuel flexible and sulfur tolerant for highly efficient H₂ or syngas production, while operating at water neutral conditions.  These reformers utilize an ultra-short channel length substrate structure, trademarked Microlith®, that is combined with advanced catalyst materials and coatings, offering significant performance and durability advantages over conventional reactors.  Most importantly, the reformers are very compact and lightweight, and lend themselves to being scaled-up to higher throughputs.  Additionally, reformer miniaturization was completed to demonstrate a small-scale, portable, integrated fuel processor capable of producing syngas with <1 ppm_v sulfur from military fuels and diesels.  This paper will focus on the demonstration of the fuel-flexible reformer along with the system design and integration with fuel cell stacks.  Test data from reforming of JP-8 containing up to 3000 ppm_w sulfur, without any upstream sulfur cleanup, in an extremely compact and lightweight package will be discussed.  Fuel cell-quality reformate was produced with <1 ppm_v sulfur where the sulfur was removed from the reformate stream as H₂S via a readily-replaceable, low-cost sulfur trap.  Results from reformer testing with other fuels, including diesels, natural gas, kerosene, and bio-fuels will also be presented.  Separately, reformate testing with 1 kW_e Solid Oxide Fuel Cell (SOFC) stacks will be shown.  Finally, 250-hour data for an adaptation of the fuel processor with a water gas shift (WGS) reactor to achieve High Temperature PEM (HT-PEM) fuel cell quality reformate (<2 vol.% CO) will also be highlighted.  Data supporting the viability and performance durability of generating SOFC and HT-PEM quality reformate streams with high power density, multi-fuel capability (including full-spec JP-8, gasoline, kerosene, bio-fuels, propane, natural gas, etc.) for various military and commercial applications, will be presented.