Cracking Vegetable Oil Into Gasoline

TU Delft in the Netherlands and Universidad Rey Juan Carlos of Spain researchers have a concept developed for the efficient catalytic cracking of unsaturated vegetable oil to greatly increase the production of gasoline and light olefins such as propane and butane. The scientists’ paper on their work was published in the journal ChemSusChem on Aug 4th 2008.

The team seems to have a novel take on the catalysts metallic structure.  By incorporating nickel onto a base commercial fluid catalytic cracking process (FCC) called equilibrium catalyst or ECat and co-feeding hydrogen into the reaction system under realistic FCC operations (525 °C, 1.1 atm), the team found that gasoline production increased 32% relative to the standard ECat. That is a massive improvement in gasoline molecule production worthy of some serious note.

Fluid Catalyst Cracking Vegetable Oil to Gasoline. Adding nickel and co-feeding H2 increased gasoline yield 32% relative to a conventional catalyst.

Contrasting to that the scientists learned that incorporating platinum with our without co-feeding hydrogen, was detrimental both to oil conversion and molecule selectivity.  This information closes a door to the very expensive platinum component often thought to be the highest form of metallic catalyst performance.  The scientists are quoted saying in a conclusion a “judicious choice of metal” is vital for performance during vegetable oil cracking.

The matter remains about coming up with hydrogen for the unit.  As adding hydrogen is a common process in most oil refineries using usually a steam process the technology is readily available.  The authors say in the study:

“This approach can be very promising and economical by utilizing recycle system for in-situ hydrogen produced to eliminate the hydrogen requirement from other sources. This concept can also lead to another potential application: co-processing of vegetable oils together with heavier petroleum feedstocks that contain metal, especially nickel, contaminants.”

“In that case, the great advantage is that metal incorporation onto the base FCC catalyst is not required while at the same time gasoline production from the vegetable oil fraction can be enhanced by exploiting the metal deposits present in the petroleum feedstock. These findings may certainly stimulate interest for directing future research in the rational design of new FCC catalysts for the production of biofuels.”

The paper has an interesting introduction that alternative fuel people might want to keep in mind.  There are several main ways to convert biomass to renewable fuels.  The list isn’t comprehensive but does get the main efforts into a short list.
·    Bioalcohols such as ethanol from the fermentation of sugars;
·    Transesterification of plant-based oils or animal fats to biodiesel;
·    Hydrotreatment of vegetable oils to renewable (“green”) diesel;
·    Pyrolysis of biomass to bio-oil, and its upgrading;
·    Gasification of biomass via Fischer-Tropsch synthesis via syngas; and
·    Catalytic cracking of vegetable oils to gasoline, diesel and light olefins similar to the standard FCC process in refineries.

The authors note that, “Depending on the feedstock type, some of the above-mentioned processes are already commercially available, but except for the FCC of vegetable oils, only the fermentation process is directly designed for gasoline (replacement) production. In addition, some of the processes above are still under development because they are very energy- and capital-intensive.”

The advantage for the new FCC process is pointed out by saying, “Thus, catalytic cracking of biomass (e.g., vegetable oils) is the only process that is able to directly produce gasoline, along with diesel and light olefins components. Furthermore, the compatibility of vegetable oil processing with the existing infrastructure of the standard FCC process makes this process much more economically feasible than other methods.”

The point being made hinges on the fact that FCC is a process with extensive support now for the oil refining business including materials and parts, experienced operators and a fully developed market.

The questions lie in the cost of operation – does feeding an FCC using vegetable oil run at higher or lower cost compared to crude and can vegetable oil source at or below the price of crude oil?  At about $2.00 per gallon for crude many vegetable oils could profitably get to an FCC for conversion and marketing.

Fluid Catalytic Cracking is a technology that many thought peaked in development several times over the past decades, but FCC just keeps on giving.  The Europeans have made a significant contribution expanding the use of FCC and there should be a high probability the new catalysts might see commercial use.

Go here to see the original: New Energy and Fuel

Comments are closed.