Unitel’s pilot unit uses little more than 4 grams per minute of JP8 to produce 20 standard liters of hydrogen per minute (0.24 kg H₂/hour), enough to generate approximately .975 kW of fuel-cell power. The system includes two gas delivery modules (air and nitrogen), and two liquid delivery modules (JP8 and water).

The catalyst Unitel uses is sulfur tolerant—the company has experience with its use in reforming gasoline with up to 150 ppm of sulfur. According to Unitel, initially the Army will use sulfur-free JP8 and over the next 12 months will switch to higher concentrations of sulfur to test just how high the catalyst can go.

(PNNL is developing a micro-channel reactor that creates a light, low-sulfur fraction of JP8 for use in reforming applications to create hydrogen in the field. (Earlier post.)

All four feeds are controlled and monitored by the computer. The outgoing products are also continuously measured and integrated, thus capturing all the data required for making exceptionally tight mass balance calculations. The actual JP8-to-hydrogen conversion takes place inside a catalytic autothermal reactor.

While we have built many reformers that run on natural gas, propane, gasoline and ethanol, the use of JP8 as a feedstock can be somewhat tricky. The design of this Army system was further complicated by the need for rapid startup and shutdown, while operating in a turndown range from 100% to 20%. Fortunately, the reforming experience that our engineers had previously obtained at Argonne National Laboratory was most helpful in this regard.

—Steve Calderone, Vice President of Unitel

Resources:

• Unitel Hydrogen Systems