With Oil Back In Power, Scientists Revisit An Old Way To Use Fossil Fuels Without Making CO2

Turns out humanity's preferred method of making power and heat for the last million years—burning stuff—isn't the only way to extract energy from fossil fuels.
In the process of burning, hydrocarbons mix with oxygen, producing heat, water, and carbon dioxide. But we can also mix hydrocarbons with halogens—the family of elements that includes iodine, bromine, chlorine—in the form of hydrogen halides. When combined with hydrocarbons, these halides only partially oxidize the fuel. The reaction also produces heat, but instead of producing carbon dioxide, it produces simple carbon.
"This has been known for a long time," said Eric McFarland, a professor of chemical engineering at the University of California, Berkeley, in a briefing last month to scientists and engineers at the Massachusetts Institute of Technology.
"A lot of the oil companies tried to do this in the 60s and the 50s and even the 40s, where they used a variety of halogens to make partial oxidation products. They stopped doing it because the price of the corrosion that is associated with halogen use and the other costs associated with them were higher than the costs of making CO2, which they didn’t care about."
Humans have since encountered a reason to care about CO2—anthropogenic climate change.
Cost remains a disadvantage for this process. It requires about twice as much fuel to produce the same amount of energy as combustion.
"You're going to use about twice as much carbon, but if you're not making CO2, that's okay," McFarland said. "It's really a more strategic use of fossil resources. So we're going to be more strategic about it, we're not going to make the CO2 that would need to be sequestered. In some ways this would be the alternative to carbon capture and sequestration."
The fossil fuel industries—which recently landed allies in the White House, the State Department, the Energy Department, and the EPA—might even like the idea of doubling demand for hydrocarbons.
Besides being emission-free, the process has several other advantages over combustion:
Instead of flame, it produces char—a pile of black material—"exactly why we use them [halogens] in flame retardants," McFarland said.
It can use existing hydrocarbon infrastructure—wells, pipelines, refineries, fueling stations: The "plan is to use the fossil resources, use the infrastructure, use the same materials we were going to use anyway, but don’t make any CO2."
It can produce the same ancillary chemicals that refineries make—methanol, olefins, ethanol, glycol, ethylene, propanol, propylene, etc.—but with no Co2 emissions. "You can go all the way to all the same products you get with oxygen as your oxidant."
It's easier to make hydrogen from natural gas using a hydrogen-halide process than the current process, which produces a lot of emissions, undermining hydrogen's potential as a clean fuel.
"We might be able to make hydrogen cheaper than they do today, using this kind of technology," McFarland said. The hydrogen can be used to produce ammonia, and either hydrogen or ammonia could power the transportation sector.
"Fossil hydrocarbons are going to be here forever. We’re going to use them until they’re too expensive to use. They’re going to be key to making this generation prosperous and hopefully the next. We don’t presently have anything that can compete with them," McFarland said.
But to use them emissions free, McFarland needs one assist from government, the same one most economists agree is needed: "a meaningful cost on carbon emissions."
Watch Eric McFarland's seminar at the MIT Energy Initiative: