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City of Barstow to Test Hydrogen-Methane Blend (Hythane) in Fleet

The City of Barstow, California has signed a Memorandum of Understanding with Hythane Company for exploring the use of Hythane (a fuel blend consisting of 20% hydrogen and 80% natural gas by volume, or about 7% hydrogen by energy) as a vehicle fuel for the city’s fleet. Using Hythane further reduces the emissions produced by using natural gas engines.

Barstow is located within the Mojave Desert Air Quality Management District (MDAQMD), which has a regional plan to encourage all high-desert cities to move forward with alternative fuel projects. In 1999, the MDAQMD started the ball rolling by providing the initial funding for Barstow’s liquefied natural gas (LNG) and liquefied to compressed natural gas (LCNG) station.

The proposed Hythane System will convert the existing natural gas fueling station in Barstow into an Energy Station offering three types of clean fuel (natural gas, hydrogen and Hythane) and integrate Hythane into the existing natural gas vehicle fleet.

The City of Barstow is going above and beyond. We helped fund a natural gas station and they are taking it a step further to a cleaner fuel. They have gone the extra step by paving the way to bring this ultra-clean 80/20 fuel to the region. We encourage other cities in the region to follow their lead.

—Violette Roberts, spokesperson for the MDAQMD

Natural gas (methane) has a relatively narrow flammability range that limits the fuel efficiency as well as the reductions in emissions of oxides of nitrogen (NOx) possible at lean air/fuel ratios.

The addition of even a small amount of hydrogen extends methane’s lean flammability range significantly. Methane has a slow flame speed, especially in lean air/fuel mixtures, while hydrogen has a flame speed about eight times faster. Methane is a fairly stable molecule that can be difficult to ignite, but hydrogen has an ignition energy requirement about 25 times lower than methane.

Finally, methane can be difficult to completely combust in the engine or catalyze in exhaust after treatment converters. In contrast, hydrogen is a powerful combustion stimulant for accelerating the methane combustion within an engine, and hydrogen is also a powerful reducing agent for efficient catalysis at lower exhaust temperatures.

In tests between Hythane and CNG engines run by the Center for Transportation Technology and Systems, SunLine Transit Agency (which currently runs two Hythane buses) and Cummins Westport, the Hythane-fueled engines reduced NOx emissions by 50%, non-methane hydrocarbons by 58%, methane by 16%, total hydrocarbons by 23% and CO2 by 7% (approximately 10 million tons per year).

These reductions were achieved with no significant change in fuel efficiency between the Hythane- and CNG-fueled engines. (Earlier post.)

Hythane is a patented fuel blend. Blends of hydrogen and CNG at higher hydrogen ratios are termed HCNG. CIty Engines, for example, is developing and marketing hydrogen/natural gas (HCNG) engines optimized for a blend of 30% hydrogen and 70% natural gas. (Earlier post.)

The Hythane Company has projects currently underway in Colorado, Arizona, Georgia, Florida, New Mexico, New York, New Jersey and internationally in China and India.



Easier to ignite and improve flame speed, does that mean slightly powerful engine and slightly better milage?


It is not that simple. For stoichiometric or near stoichiometric SI engines with bout 12:1 compression ratio it is true. By the way, such engine fueled by hythane and with 3-way cat is the cleanest IC engine. However, for lean-burn high compression engines using compression ratio more then 16:1 and gas/air mixture lower then self-ignition but still flammable, ability of engine to withstand high peak pressure (directly proportional to flame speed) is limiting factor (like in conventional diesel engine) and will dictate slightly lower compression ration and hence efficiency.


well everything sounds gd with new engine but anyone fort about the methane engine

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