Speaking of Joule, how is this different from other fuels made directly from sunlight, CO2, and water?
There are the electrofuels, and the Joule technology — these also make fuels directly from CO2, sunlight and water — the same material that plants use to make biomass. With the Lehigh technology, however, the light harvesting mechanism is not the same, and thereby is not limited by photosynthetic efficiency.
Is Methanol a Viable Fuel?
There have been methanol vehicles developed over the years, but a combination of short range, the toxicity of methanol itself, and the cost of building out the infrastructure — have bedevilled deployment of the technology. Mostly, we’ve seen methanol vehicles in China.
But hang on — you can make ethanol, for example, from methanol. Enerkem does so, as a matter of fact, as part of their process.
Celanese TCX is another process. Now, Celanese has owned a core technology for years that reacts methanol and carbon monoxide with catalyst, to make acetic acid. It’s newer TCX process converts acetic acid to ethanol. ZeaChem also has a process for this.
Not to mention, the Mobil MTG process, which converts methanol to gasoline.
In this process — which ExxonMobil has been generally touting in recent years as a means of converting coal to gasoline — “methanol is first dehydrated to dimethyl- ether (DME). Then an equilibrium mixture of methanol, DME and water is converted to light olefins (C2-C4). A final reaction step leads to the synthesis of higher olefins, n/iso-paraffins, aroma- tics and naphthenes. The shape selective MTG catalyst limits the hydrocarbon synthesis to C10 and lighter.”
Which is to say, lots of ways to use methanol as a renewable fuel. There’s also this duel fuel system system, which was developed a few years back and marketed under the “Itz-a-Gaz” brand.
In this system, its developers explain that “the primary fuel used to propel the vehicle is either gasoline or diesel. The secondary liquid fuel is an alcohol optimally methanol. Methanol readily dissociates into hydrogen and carbon monoxide at a temperature as low as 300 degrees C. This dissociation reaction can be driven by the heat of the exhaust gases. In fact slightly more than 20% additional energy is gained in the products of the disassociation reaction and this additional energy is essentially recuperated from the hot exhaust.
“The mixture of hydrogen, carbon monoxide, and gasoline or diesel will burn in a highly lean (excess air added) mixture of fuel and oxidant. This allows for lean combustion of the fuel in an internal combustion engine that can be turbocharged and operates under a high compression ratio.”
The Bottom Line
This Lehigh technology has a long ways to go towards commercial scale — but it’s a rare bird amongst biofuels technologies — a real disruptor, if it proves possible to industrialize, scale and the yields pan out as hoped for.
One thing we sure hope pans out: the use of waste or saline water. Far more sustainable. Should the technology prove to be able to use CO2 extracted from flue gas — as well as power plant coolant — why, that would be an excellent integrated project for coal-fired power plants that could revive their economics while mitigating their emissions problems.
“Currently, there is no commercial route to directly and photocatalytically produce liquid fuels,” McIntosh told Lehigh technology writer William Johnson in an extended review of the technology, here. “Certainly, using sunlight to create liquid fuel is a high-risk, high-reward proposition, but that is what is so exciting. The implications for our nation’s economy are significant.”
This article was originally published on Biofuels Digest and was republished with permission.