Hydrogen production and delivery are key barriers to fuel cell vehicle (FCV) implementation. This project demonstrated an on-site hydrogen production technology for FCV applications. The compact steam methane reformer offers advantages due to the abundant supply of natural gas and existing pipeline infrastructure.

Field validation objectives included the fuel station’s criteria emission testing and assessment of overall process efficiency. Primary criteria emissions testing included nitrogen oxides (NOx) and carbon monoxide (CO). Data collection objectives also included monitoring other solid and hazardous waste streams, durability, reliability, safety issues, efficiency, and hydrogen losses. This type of data allows for comparison with other conventional and alternative fuel vehicles. In addition, the project was to provide hydrogen for initial testing of the demonstration FCVs.

Technology Description

This demonstration project field tested a compact version of a traditional steam methane reformer. The reformer is a sub-component of the larger fuel processor. The reformer converts steam and natural gas into hydrogen (H2), carbon dioxide (CO2), and CO. Competing variations of the reformer offer quicker startup and improved load following. High energy efficiency remains an advantage of traditional steam methane reformers.

The manufacturer delivered a new reformer to Marine Corps Base Camp Pendleton, California, in January 2010. The project team subsequently took steps to install, commission, and start up the reformer. The team conducted emission testing in February 2010. Permanent system integration efforts followed and included setup of the utility connections, controls, and compressor staging. Integration efforts concluded in June 2010. Startup testing occurred between July 2010 and December 2010.

Reformer testing included intermittent start-up and short-term operation. Operating events were at most 3 days, a fraction of the 1,000 hour objective. Lack of integrated controls was an underlying factor resulting in shutdowns. Automated feedback controls would have helped extend operating time while minimizing the need for operator attention to achieve emission, efficiency, reliability, and durability objectives.

Demonstration Results

The U.S. Army Aberdeen Test Center measured emissions while the reformer operated at 25% and 50% of full capacity. Emissions at these loads met the objectives for CO2, NOx, and sulfur dioxide (SO2). The system failed to meet emission objectives for CO and methane (CH4). Also, the reformer could not operate for sustained periods necessary to complete 75% and 100% load testing.

The team collected pre-commissioning samples from the reformer to evaluate hydrogen quality. Pre-commissioning samples met fuel quality objectives. With the exception of water, contaminants were below the Hydrogen Quality Guidelines in Society of Automotive Engineer (SAE) J2719. The manufacturer hypothesized delivery in rainy weather as the source of water in the samples.

The system performance objective was 65% reformer efficiency. Efficiency is determined as the ratio of hydrogen energy (output) divided by natural gas energy (input). Efficiency is a primary benefit of on-site reformation relative to competing hydrogen delivery technologies. Reformer test runs were well below the objective loads and duration necessary to draw conclusions on efficiency.

The demonstration objectives included monitoring hydrogen leaks to the atmosphere. The team could not evaluate losses from the reformer due to lack of operation. For the balance of station, the compressor was the primary source of leaks, and resulted from component failures. Hydrogen losses from the compressor did not present a safety issue, as the release point was from the elevated vent, above the other equipment. Routine leak checks indicated losses from the piping were very small.

The system failed to meet the performance objective for reliability. The project team executed numerous startups and short-term operating events. System operation ranged from several hours to 3 days. The system could not operate steadily for an extended period of time. As a result, the system did not meet the 80% reliability objective over the 1-year testing period.

Total operating time for the reformer was minimal and insufficient to evaluate the durability objective. Durability is of interest as each startup and shutdown action expands and contracts the vessel and tubes, which contributes to eventual material failure. Given this, low reliability will shorten the useful life of the reformer.

The reformer fell short of the maintainability objective. Initially, the team envisioned routine service on a quarterly basis for the replacement of consumables. The performance objective was five or fewer trouble calls, assuming steady operation over 1 year. Under actual use, the reformer could not reach steady operating status. This was due to inherent controls design as opposed to system durability.

Implementation Issues

No significant safety incidents occurred during the test period. The quantitative objective included four or fewer hydrogen leaks, all below 10% of the lower explosive limit concentration. Personnel noted a potential burn danger near the reformer’s stack. Stack insulation, personnel safety gear, and personnel caution will help mitigate the risk of burns. Also, the fire safety panel issued several false alarms. Routine servicing will help avoid false alarms and help ensure the panel operates to manufacturer specifications.

No trespassing or vandalism occurred during the testing period. As a result, the station met the performance objective for security. Factors promoting security include: (1) routine daily use by the Marine Corps test team; (2) daily contractor occupation of the adjacent maintenance facility; (3) locking of the gate entrance outside normal working hours; and (4) periodic patrols by the military police and railway authority personnel.

Overall, the reformer requires further development to be field ready. From a user perspective, the system did not meet the expectations for modular installation, quick startup, unattended operation, and hydrogen quality. Each aspect requires further engineering and development before the system can be expeditiously installed, commissioned, and operated on a routine basis.