Under a new research directive at Ames National Laboratory, scientists are honing in on a way to perfect a process called gasification to create cheap ethanol from almost any carbon source without fermentation.
If they’re successful, crops, agricultural waste, lawn clippings, raked leaves, sewage sludge and garbage could all be turned into ethanol using the same efficient process, in the same facility, under one roof.
We’ve covered the process of gasification for ethanol production before, but this new research appears to be a huge step forward in making ethanol using gasification.
Although cellulosic ethanol made from non-food plant material and garbage is already rising quickly as the next viable source of second generation biofuel, its current production method has many built-in inefficiencies.
The current process involves the use of acids and/or heat, enzymes and fermenting microbes to get from the harvested plant material or garbage to a fuel that is usable in your car’s engine — all of which add up to significant inputs of money, time and energy.
If all of those extra steps could be cut out of the process of turning plant material or garbage into ethanol, the efficiency would go up and the amount of energy actually gained from the process would increase too.
This energy gain is important because one of the main criticisms of ethanol, and biofuels in general, is that they are an inefficient way of making fuel and, some argue, actually take more energy to produce than they put out — although this claim is very much debatable, and most probably wrong.
So how does gasification work and what are some of its problems?
Gasification is a process that turns carbon-based feedstocks under high temperature and pressure in an oxygen-controlled environment into synthesis gas, or syngas. The syngas can then be converted into ethanol using a catalyst.
Syngas is made up primarily of carbon monoxide and hydrogen (more than 85 percent by volume) and smaller quantities of carbon dioxide and methane. It is the carbon monoxide fraction of syngas that is converted to ethanol as it passes over a catalyst.
Ironically, although the Ames scientists envision gasification ethanol as the way of the future, the actual gasification process has been known about and used for the better part of 200 years.
Gas produced from the gasification of coal was used to light street lamps and for cooking before the invention of the light bulb and widespread production of electricity and natural gas.
In fact, people have known for a long time that gasification of carbon-based materials can directly produce ethanol when reacted with a catalyst— it’s just that, up till now, the process also produced a lot of undesirable and potentially toxic byproducts along with the ethanol.
Apparently not one to let 200 years of status quo get him down, Ames chemist Victor Lin set out to find a way to get rid of these undesireable byproducts of the gasification syngas-to-ethanol process and increase the yield of ethanol.
Along the way, his research group discovered they could greatly increase the amount of carbon monoxide generated by using a porous foam-like material in which all the interior surfaces were coated with the metal alloy catalyst.
This provided a huge amount of surface area on which the syngas could react with the catalyst, thereby enhancing carbon monoxide generation and, in turn, increasing the amount of ethanol produced while largely eliminating the undesirable byproducts.
The beauty of gasification is that it converts all of the input material (whole plants, garbage, etc.) into ethanol. In contrast, the acid/heat/fermentation process always leaves behind materials that cannot be converted to ethanol by microbes. As Dr. Lin says:
“The great thing about using syngas to produce ethanol is that it expands the kinds of materials that can be converted into fuels. You can use the waste product from the distilling process or any number of other sources of biomass, such as switchgrass or wood pulp. Basically any carbon-based material can be converted into syngas. And once we have syngas, we can turn that into ethanol.”
I’m excited and curious to see where this research leads as it seems like one of the most promising developments I’ve run across recently. Let’s hope they can get it to the demonstration phase quickly.
Anybody else out there have experience with syngas production or ethanol production from syngas without fermentation?
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