Using Woody Biomass To Extract Hydrogen From Water & Carbon From The Atmosphere

bio_wood_chips_x220.jpgWood contains carbohydrates, and is sort of obvious, the "hydrate" suffix in the term "carbohydrate" implies hydrogen. It gets there from water, during photosynthesis. By simple pyrolysis, essentially just a matter of heating wood in an oxygen starved "retort," it's easy to extract this naturally collected hydrogen and a bit of methanol, setting aside, if we wish, the charcoal byproduct for sequestration. The charcoal might just be "buried" as suggested in a research paper on this topic published in the journal Biomass and Bioenergy Technology Review. Alternatively, the charcoal byproduct of wood pellet pyrolysis could be used for a soil amendment. Viewed and managed in this way, trees become the ultimate climate protection machines, certainly deserving of the Richard Branson-offered prize. But who gets the award? The extraction is very old technology after all. Judging by a few of the comments made at Technology Review blog, we're guessing that a number of our readers will be thinking that it is a waste not to burn the carbon "char" byproduct for energy. To evaluate this notion, we need also to understand that all hydrocarbons in commercial use...there's that "hydro" prefix again... function as hydrogen carriers and that much of the energy extracted from gasoline, for example, comes from the combustion of that carried hydrogen. (Coal is not generally considered a hydrocarbon.) The critical difference is that woody growth removes carbon from the air, while fossil fuels, hydrocarbons included, only put more in. This is definitely not a stretch contrast. Gasoline refining is one of the single largest commercial markets for hydrogen. Refineries add that hydrogen to let them assemble more straight chain, hydrogen rich molecules that burn well and are less toxic (it's called "cracking"). That refinery-used hydrogen, for the most part, is extracted from the pyrolysis of natural gas, a fossil fuel.

Of course it was those clever Scandinavians, once again, who got us thinking out of the wooden box. Perhaps they deserve the award.

Image credit and referral to original source: Via Technology Review.

Tags: Biomass | Scandinavia


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