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Diversified Energy Demonstrates Glycerol Combustion System

Diversified Energy Corporation has successfully demonstrated a glycerol combustion system for which it holds an exclusive worldwide license from the developer, North Carolina State University. The system efficiently burns the glycerol byproduct generated during the manufacture of biodiesel; energy created through the combustion of glycerol can then be used for process heating applications or electricity generation.

Glycerol combustion system prototype in action. Click to enlarge.

The university has built and tested a 100,000 Btu/hour prototype burner with pure glycerol, crude glycerol from a biodiesel process, and glycerol with water. Diversified Energy is now seeking commercialization partners for market introduction.

The manufacture of biodiesel through transesterification results in approximately one pound of crude glycerol byproduct for every nine pounds of biodiesel produced. As the biodiesel industry has expanded, so has the supply of crude glycerol/ Glycerol is expected to reach in excess of 350,000 tons/year in the US and 600,000 tons/year in Europe.

Crude glycerol contains artifacts from the biodiesel process such as catalysts, alcohol, and soap and is therefore costly to refine into higher grade, pure glycerol. As a consequence, crude glycerol market prices have collapsed and the biodiesel industry is struggling with viable options for the glut of glycerol on hand.

The combustion of glycerol will produce 16 MJ of heat per kilogram of glycerol burned which could be provided back to the biodiesel process, another co-located system, or converted into other energy forms like electricity. However, the combustion of glycerol has been challenging because of technical, safety, and cost obstacles.

By nature, glycerol has a high viscosity, high auto-ignition temperature, and low heating value. It is difficult to flow the product into a burner, hard to ignite, and even more challenging to maintain a flame. In addition, if the glycerol is not completely combusted it is possible to generate toxic gases.

The patent-pending process from NC State University is based on a novel spray atomization swirl burner architecture that overcomes the technical and safety issues. This is coupled with pre-heating the combustion chamber, maintaining heat retention, maximizing radical retention, and carefully interacting air and fuel flows. The system is extendable to any liquid fuel having an ambient viscosity of greater than 20 centistokes.



there is another research group at Rice University which has developed a way to refine raw glycerol into valuable industry feedstocks like succinate and formate using E Coli bacteria; I think that will do more to improve the economics of biodiesel production and tackle the glycerol glut than this process.


Yes. The Rice research hopes to turn glycerol into ethanol. An immediate market if it works.



It looks like this glycerol could be burned in any of the hundreds of #6 fuel oil burners in power plants across the country (most of them are abandoned in place because their furnaces are burning natural gas now).
#6 fuel oil is a solid at 80 degrees F, pours at 110 degrees F, has a viscosity of of over 100 centistokes at 110 degrees(temperature at which it is stored), and a viscosity of over 50 centistokes at 200 degrees (temperature at which it reaches the burner nozzles).
Superheated steam would be used to blast the oil into a fine mist at the spray nozzle. these burners have been used for about a hundred years on industrial scales.
It looks like this company has just reinvented the wheel

Alex Kovnat

Is it possible to burn glycerine in massive, low-speed, 2-stroke Diesel engines like they use on ships?

P Schager

Diesel engines can, after all, run on straight vegetable oil, which is just the same thing as biodiesel before the glycerol has been removed and the molecule broken up to reduce the viscosity. So mixing glycerol back into the fuel will work fine, with emulsifier additive or engine tricks to deal with its tendency to separate. Just-in-time blending, maybe, or extra injectors. A good application would be for ships near port, where they are already taking extra steps to burn low-sulphur fuel (e.g. near the Port of LA which is pollution-limited). Glycerol is already sulphur-free.

Further from the sea, locomotives and home heating oil replacements would be good candidates.

Glycerine acetate could be made, which is apparently a good pour-point depressant additive, one which makes biodiesel keep flowing at lower temperatures. Or propylene glycol, which is a low-toxicity alternative antifreeze that can be used undiluted at zero pressure (or negative pressure, so you can detect leaks before they leak anything on the ground).

Note that as the industry shifts to solid catalysts, the above-mentioned contaminants will go away as a problem, and most of the available glycerine should be pure enough to eat. Livestock feed additives are another use. The glut will evaporate quickly once investors are confident industry support isn't about to have the rug pulled out from under it.

Steve Lord

I am looking for emulsifiers to blend with glycerol and biodiesel to allow the blend to be burned in smaller type industrial burners. Can anyone make a recommendation or provide me with a trade name?

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