UC Davis process produces gasoline-range hydrocarbons from biomass-derived levulinic acid; field-to-tank yield of >60% claimed
04 February 2014
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| GC-MS chromatogram of the liquid products obtained after hydrodeoxygenation of angelica lactone dimer. Source: Mascal et al. SI. Click to enlarge. |
Researchers at the University of California, Davis have developed a process for the production of branched C7–C10 hydrocarbons in the gasoline volatility range from biomass-derived levulinic acid with good yield, operating under relatively mild conditions, with short reaction times.
Considering that levulinic acid is available with more than 80% conversion from raw biomass, a field-to-tank yield of drop-in, cellulosic gasoline of more than 60% is possible, the researchers claimed. A paper on their work is published in the journal Angewandte Chemie International Edition; UC Davis has filed provisional patents on the process, and is making it available for licensing.
| KiOR |
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| As a very rough benchmark on yield, cellulosic gasoline and diesel company KiOR, which uses a different pathway for fuel production (the production of renewable crude from biomass followed by catalytic cracking to upgrade to fuels), calculates that one bone dry ton of woody biomass contains hydrocarbons approximately equal to 2.8 barrels of oil (117.6 gallons US). |
| As noted in its quarterly report (10-Q) for the quarter ending 30 September 2013, KiOR had obtained a yield of 72 gallons per bone dry ton (about 41% gasoline, 37% diesel, 22% fuel oil) for between $2.60 and $2.80 per gallon. |
| Its long term target is 92 gallons/BDT. KiOR has halted commercial production this year in order to tune up its yield and tune down its costs. (Earlier post.) |
The process dehydrates the biomass-derived levulinic acid under solid acid catalysis and then treats the resulting angelica lactone with catalytic K2CO3, producing the angelica lactone dimer (ALD). This dimer, in turn, serves as the feedstock for hydrodeoxygenation, which proceeds under relatively mild conditions with a combination of oxophilic metal and noble metal catalysts to yield the branched hydrocarbons in the gasoline range.
Traditional diesel fuel is made up of long, straight chains of carbon atoms, while the molecules that make up gasoline are shorter and branched. Biodiesel, refined from plant-based oils, is already commercially available to run modified diesel engines. A plant-based gasoline replacement would open up a much bigger market for renewable fuels.
The levulinic acid feedstock for the new process can be produced by chemical processing of materials such as straw, corn stalks or even municipal green waste. It’s a cheap and practical starting point that can be produced from raw biomass with high yield, Mascal said.
Because the process does not rely on fermentation, the cellulose does not have to be converted to sugars first. Coauthors on the paper are postdoctoral researchers Saikat Dutta and Inaki Gandarias.
Resources
Prof. Mark Mascal, Dr. Saikat Dutta, Dr. Inaki Gandarias (2014) “Hydrodeoxygenation of the Angelica Lactone Dimer, a Cellulose-Based Feedstock: Simple, High-Yield Synthesis of Branched C7–C10 Gasoline-like Hydrocarbons,” Angewandte Chemie International Editiondoi: 10.1002/anie.201308143
" KiOR had obtained a yield of 72 gallons per bone dry ton (about 41% gasoline, 37% diesel, 22% fuel oil) for between $2.60 and $2.80 per gallon."
If true, the multi-$billion deep offshore and frozen Arctic oil wells are going to seem VERY expensive.
Posted by: kelly | 04 February 2014 at 05:28 AM
The biomass input is not the whole story; this process includes hydrodeoxygenation, meaning some other source of hydrogen is required. Even at 92 gallons per BDT, the billion tpy of biomass potentially available in the USA would not slake the demand for motor fuels. The 41% yield of gasoline-range fractions falls far short of the 130-odd billion GPY consumed here.
As always, something else must do the heavy lifting. Electric propulsion can do that, leaving biofuels to fill the remaining niches.
Posted by: Engineer-Poet | 04 February 2014 at 06:46 AM
The argument that we can not replace ALL oil with biomass is wearing thin. If we can replace 10% we get rid of middle east oil.
Posted by: SJC | 04 February 2014 at 07:31 AM
The problem with comparisons to Kior is that Kior is essentially a petroleum refinery that uses biomass instead of crude oil. Mild, chemical-catalytic methods will lead the future of biofuels in terms of yield, capex, and opex.
Posted by: Mark Mascal | 04 February 2014 at 09:01 AM
@ Mascal,
What is the break down on the remaining 40%. Is it a disposal issue or potential co-products? Not being a chemist or fuels guy, why bother to de-oxygenate, could practicle engines be adapted to the ALD as they have to other oxygenated fuels?
Posted by: Tim Duncan | 04 February 2014 at 02:52 PM
Hi Tim
The mass balance is in condensation products (humics) from levulinic acid production and small carbon fragments that cleave off during hydrodeoxygenation. Thus, no serious waste stream issue. Yes, the dimer could be potentially used as an oxygenate, but the big market is in the
Posted by: Mark Mascal | 04 February 2014 at 06:02 PM