Diesel from waste: Simple, energy-efficient process for producing high-quality fuels from biomass

February 3, 2011, Wiley

(PhysOrg.com) -- For the last ten years, biodiesel in the form of fatty acid methyl ester has been promoted as a replacement for fossil-fuel-based diesel fuel. It was soon found that this has its problems because the required plants, such as rape, occupy cropland that can then no longer be used to grow food. A second-generation biodiesel is now supposed to be gained from plant waste.

In the journal , Avelino Corma and his team at the Universidad Politecnica de Valencia (Spain) have introduced a highly promising new process that is energy efficient and delivers high-quality fuel.

The usable materials in biomass—oat hulls, almond shells, bagasse (fibrous remains of sugar production from cane), sunflower-seed shells, corncobs, waste from olive oil production—consist mainly of cellulose-like carbohydrates. “A number of different approaches have been developed,” reports Corma, “many of them suffer from an unfavorable energy balance because they require a lot of energy themselves.”

Corma and his team have now successfully developed a simple, cost-effective process that is energy-efficient and also does not require any organic solvents. The first step is the conversion of biomass into furfural an established industrial process. In an adaptation of another current process, furfural can be converted with high selectivity into 2-methyl-furfural (2MF), a ring consisting of four carbon atoms and one oxygen atom, with a side chain consisting of a methyl group (–CH3).

“This 2MF is the starting material for our new diesel synthesis”, says Corma. First, three molecules of 2MF are linked together. This requires water and an acid catalyst. This reaction causes one third of the rings to open and each link to two other rings (hydroxy alkylation/alkylation). The aqueous phase, which also contains the catalyst, separates from the organic phase, which contains the intermediate product, on its own. It can easily be removed and the catalyst recycled. In a second reaction, the two other rings must also be opened and their oxygen atoms removed. This reaction uses a special platinum-containing catalyst (hydrodeoxygenation).

“In the end we obtain 87% of the diesel fraction in the form of branched hydrocarbon chains with nine to 16 carbon atoms,” claims Corma. “This is the best yield reported in the literature thus far for biodiesel synthesis.” Gas-phase and lower molecular weight byproducts can be used to produce heat. The resulting biodiesel is of excellent quality (cetane number 71, pour point -90 °C) and can be mixed directly with conventional fuels.

Explore further: Biomass as a source of raw materials

More information: Avelino Corma, Production of High-Quality Diesel from Biomass Waste Products, Angewandte Chemie International Edition, Permalink to the article: dx.doi.org/10.1002/anie.201007508

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not rated yet Feb 03, 2011
It doesn't sound like ready diesel yet, unless you have fuel line boilers in your car.

You need a pour point of down to -20°C or it will just turn to gel in your fuel lines when the weather goes bad.
not rated yet Feb 03, 2011
Ah, as I suspected. The original article states that the pour point is -90°C. Heads up, editors.
1 / 5 (2) Feb 03, 2011
Or we could conserve, by driving less, eating locally, and use videophones instead of driving or flying on holidays. If you insist on being there, pay your dues. No subsidies for polluters does the trick too.
5 / 5 (1) Feb 03, 2011
Or we could conserve

It isn't an either-or question. Even by conserving your resources, you still have to come up with a feasible method of synthesizing fuel or you'll simply run out of it some time later.

Unless you're one of those loonies who think that fuel and/or energy should be produced in an inefficient manner so that it would be artifically expensive and therefore harmful to everybody, just so people wouldn't use so much of it.
not rated yet Feb 04, 2011
This and a patch-work of other techniques is the future. Bio-diesel has all the bets covered, including the little guy that still wants to be able to work on his car with out fear of electrocution or pressure ruptures.
5 / 5 (1) Feb 04, 2011
Ah, as I suspected. The original article states that the pour point is -90�C. Heads up, editors.

Editors? From the look of it, this is a copy-paste of a press release. There was no reporting done here. No investigation. Of course, the material is free and I love this website, but you gotta know there is zero fact checking going on around here.
not rated yet Feb 06, 2011
Or we could conserve[...]

Conserve as much as you like, fossil fuels will still become scarcers and more expensive in the not too distant future. The Earth doesn't care whether you burn all the coal or oil in 100 years or 200 years.

Most increases in energy-efficiency have lead to increasing energy consumption. Nowhere is it more apparent than in computer hardware; we could all be using commodore 64's fabbed in 32 nm that consume no more than a few milliwatts, but despite something like a 50% per year improvement in the number of MIPS or FLOPS per watt we keep finding interesting ways to use enough more computational power to more than drown out the improvement in energy efficiency.

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