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Centia Biofuels Process Produces Bio-gasoline Similar to Conventional Unleaded Gasoline

The three stages of the Centia process, with different reforming pathways for different fuels. Click to enlarge.

Diversified Energy Corporation (DEC) has produced a bio-gasoline fuel very similar to traditional unleaded gasoline using its Centia process, licensed from North Carolina State University (NCSU).

Centia is based on a three-step thermal, catalytic, and reforming process that has the potential to turn virtually any lipidic compound—e.g., vegetable oils, oils from animal fat and oils from algae—into 1-for-1 replacements for petroleum jet fuel, diesel, and gasoline. (Earlier post.)

The three steps are:

  • Hydrolytic conversion. The feedstock is heated under pressure to separate free fatty acids from glycerol in the triglycerides in the feedstock. Centia accomodates any lipidic compound without modification to the production process.

  • Decarboxylation. The free fatty acids and solvent are heated, pressurized, and passed through a catalyst in a reactor to produce n-alkanes, the building blocks of fuels.

  • Reforming long-chain alkanes. The resulting alkanes—straight-chain hydrocarbons of 15-17 carbon atoms—are reformed into branched alkanes and ring structures. The process is optimized to maximize C10 through C14 iso-alkanes. The alkanes can be reformed differently to create a variety of fuel types. By varying the catalyst, temperature, pressure, and kinetics of this third step, Centia can produce a wide range of biofuels that mimic their petroleum-derived counterparts.

The bio-gasoline tests were conducted at NCSU using demonstration reactors, operated under temperature and pressure with a proprietary catalyst developed specifically for the Centia bio-gasoline process.

Starting with an input mimicking what would have originated as soybean oil, the process generated a fuel closely resembling the carbon number profile and molecular composition of unleaded gasoline. A mass conversion efficiency in excess of 90% was achieved.

Further development, optimization, and testing activities are being planned, including an end-to-end Centia system demonstration to make bio-gasoline, Jet A-1/JP-8, and renewable diesel. Development work also is continuing on various steps in the process to show that the fundamental chemistry works regardless of renewable oil input source.

In addition to the bio-gasoline work, Centia has completed the construction and demonstration of a glycerol burner that will safely burn the glycerol byproduct from Centia and provide an energy source back into the process. This same burner could make productive use of the crude glycerol generated from traditional transesterification-based biodiesel plants.

Diversified Energy is also the developer of the HydroMax gasification process. (Earlier post.) In December, the US Department of Defense selected Diversified Energy Corporation and Velocys to design a portable synthetic fuel production system based on DEC’s HydroMax gasification technology and Velocys’ advanced Fischer-Tropsch approach. (Earlier post.)


Healthy Breeze

So, how many liters of bio-gasoline do they get from a barrel of soy bean oil? What's the EROIE? What's the net carbon impact?

Alex Kovnat

Diversified Energy Corporation's success in producing gasoline - not alcohol - from biomass, ought to remind us that the reason why alcohols (methanol and ethanol, also butanol) have been proposed as alternative fuels for spark-ignited engines is because they're readily producible from domestic raw materials, rather than petroleum from places like Saudi Arabia.

So we need to ask ourselves: if DEC's process works out, should we stick with gasoline as the standard fuel for spark-ignited engines, or do alcohols offer advantages as fuels besides producibility from biomass?

I think there are merits to ethanol besides not having to be imported from the middle east. For example, a high-ethanol content fuel has an antiknock (octane) rating high enough that you don't have to compromise spark timing for no other reason than avoidance of preignition or detonation. The high heat of evaporation provides an intercooling effect for turbo- or mechanically supercharged engines.

Also, it is well known that despite poor miles-per-gallon (or, kilometers per liter) caused by lower energy content, methanol and ethanol are popular as racing fuel because an engine develops more power with such fuels than it can with gasoline.

Regarding Diesel engines: DEC's process is of interest in that it produces the same kind of hydrocarbons one finds with conventional Diesel fuel, rather than the fatty acid methyl esters characteristic of "BioDiesel". So we need to ask, is there merit in using fatty acid methyl esters besides producibility from biomass? Again, I think so. They offer good lubricity, which is important in Diesel fuel injectors.

All in all, I think that with all the developments in biomass-based fuels we have seen in the last few years such as DEC's process, the biofuels industry has a secure future.


The mass conversion efficiency of 90% answers your first question.


There are many processes to make liquid fuel, so we can add this to the list. What is lacking is finding the right feedstock in the amounts that we need, even if we significantly increase efficiency.


The following chart might answer your question. Provided private and government sectors take steps to finance the development.

Gallons of Oil per Acre per Year
Corn . . . . . . . 15
Soybeans . . . .48
Safflower. . . . . 83
Sunflower . . . 102
Rapeseed. . . 127
Oil Palm . . . . 635
Micro Algae . .1850 [based on actual biomass yields]
Micro Algae . .5000-15000 [theoretical laboratory yield]


I suspect there is a Lipids Limit which has a percentage relationship to the Photosynthetic Limit cited by some commentators. That is, a practical limit to the amount of energy per year that can be harvested from triglycerides. Oilseeds and algae ponds are limited by acreage and the production of animal fat is a tradeoff with crop growing. I doubt then whether it is physically possible to grow both enough food and to keep 800 million cars and trucks on the road. Lipids based fuel should therefore remain a minor niche and the effort should go into cellulosic fuels and alternative transport.



I am no longer as optimistic about algae as I once was. And I've learned not to hold my breath. So the feedstock problem remains.


I can see this process creating jet fuel to keep us in the air, at least.

Healthy Breeze

I'm not yet buying the 90% mass conversion number. That doesn't tell us what the energy inputs are for boiling, processing, etc. We're not looking for a process with corn ethanol EROIE.


Well, this is interesting:

No convincing evidence for decline in tropical forests.

I regard this news as mixed. On one hand, there's a healthy amount of natural reforestation going on to balance out the deforestation. On the other, the data we have sucks, so there's a large error bar on that conclusion. We need better data.


@ Cervus,
Believe me holding ones breath is not a good idea, neither is digging ones heels till everyone else gives up.
Plenty of doubters re algae, little constructive thinking.
Supporting evidence as to the high yeilds acheivable from this group are abundant and have a long history.
There are likeways well known pollution remediation qualities attributable to algaes,wich are very efficient plants.
We suffer from algae blooms when temperature and low water flows combine with any trace of fertilizer combine these blue green algae are highly toxic and as in saltwater toxic blooms one of the problems is the rapid growth.
The point is that when the bloom fails it is because nutrient is exhausted, or temp fails.
You sate that there needs be a reliable supply in sufficient quantity, But can't accept that all the necessary conditions are met on a permanent basis wherever humans or livestock and other troublesome polluters exist.
I dont know why these simple realities are routinely given so little attention.
Many of the critical comments put up distractive reasons wich are easily dismissed and demonstrate a lack of imagination that I find to be towards spoiling.

The good news is that figures, like those from gr above continually acheive air and from the perspective of beleivers are very credible.
The implementation of these important figures seem to me very simple, although some proponents seem to be going a more complex stand alone route.
The simple, large scale method of production will require integration with existing plant, will be very usefull in water remediation and purification have low energy inputs and be low cost, long term and sutinable.
I recomend to anyone to research the concept and then add comment.


So we need to ask ourselves: if DEC's process works out, should we stick with gasoline as the standard fuel for spark-ignited engines, or do alcohols offer advantages as fuels besides producibility from biomass?

Alex, alcohols suffer from a number of disadvantages:
- lower energy density (kJ/l) than gasoline.
- tendency to absorb moisture, which leads to corrossion issues, inablity to use existing pipelines and storage tanks and the potential to form a water layer (very bad).
- burns with an invisible flame (ouch!).

Ethanol also suffers from very low efficiency when produced by fermentation.

OTOH, alcohols do have high octane numbers.

On the balance I think methanol and ethanol are out. Higher alcohols (butanol, etc.) can still be considered. Sticking to gasoline has obvious advantages.


There is lots of talk of hydrogen, EV, CNG and many other methods, but we still have more than 100 million gasoline cars out there in the U.S. and probably will for some time. 1 million hybrids is less than 1% of the fleet and 5% ethanol is just what it says. We could use synthetic gasoline for the real problems now.


concerning algae:

monoculture forms of algae production are very unlikely to become anything other than a method to produce nutraceuticals, the reason for this is simply the cost of managing algae be it photobioreactors or open air ponds both are costly

the only viable way for algae to produce bio-fuel feedstocks is if the bio-crude is a by-product and not the main product

the one exception is gmo algae, which could happen, doubtful, but maybe there will be a breakthrough and if there is you'll never produce it in europe as they wouldn't let the gmo in

i suggest looking at they promote the use of wild algae something we are already producing way too much of

rickey Williams

You have a wonderful concept.
In the artical as should be done the pros and cons are listed.
By education I'm a mathematician with a minor ub Cghemistry and phyhsics. I have eighteen years in Analtical Chemistry and five years in the Chemistry of Semicondutors. I have twenty two years in doing computer support for scientist and engineers, Also, I have a heavy weight computer capabled of doing processing of large amounts of data.
I'm also disabled and can't have home much.

I would like to participate in the search for the right algae or repeat experiments you do for verification.

I have the space and the time. If I could get a firm comitment I would be happy to go the Small Business Administration to get fund to build a lab, stock it, and do the required work.

Would you be interested in helping?

rickey williams

V. Ray

this message is to Rickey Williams in reference to his posting of 8/5/2008

Please contact me at: [email protected]

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