WFU Biofuels

Wake Forest students, faculty, staff and associates making and testing vegetable-oil based fuels.

Tuesday, November 29, 2005

Sugar Catalyzed Reaction

Recently there has been a lot of buzz by a Japanese group’s solid acid catalyst made from sugar (Nature, vol. 438, p 178, 2005). They reported converting FFA’s to the ethyl esters. This catalysis is special because it is hydrophobic and consists of sheets of fused rings with covalently attached SO3H groups.

Our group decided to make some and see how well it works. Making the catalysis was easy. We took 2 g of sucrose and heated at 400C for 15 hours under nitrogen. The remaining 0.5 g (loss of mass is due to dehydration of the sugars) was ground and heated to 150C in concentrated H2SO4 for 15 hours under nitrogen. After washing and drying, the yield was 0.61g (about a 30% mass return from the starting amount of sucrose)

From reading (Ind. Eng. Chem. Res. 2005, 44, 5353-5363) about solid acid catalyst we saw where most reactions were using 1 to 5% catalyst by weight. Also the WVO we are using is not tremendously high in FFA based on some initial titrations. So the rational for using this catalysis was to convert any FFA’s to the methyl ester in a fashion that would make the subsequent base step much easier. We also wanted to see if this reaction could also be used to convert the oil over to the FAME. This would mean using a large excess of MeOH. Here were the conditions:

12 g WVO
12 g MeOH (100% by weight, large excess to try to push oil over to ester)
0.6 g Cat (5% by weight or about 40 g/L)
Heat at 75 C for 12hours (again long reaction time for the oil to convert)

After heating, the reaction was filtered and the catalyst was washed with 20 mL THF and 20 mL hexanes. Solvent was removed by rotary evaporation. The pale yellow oil was centrifuged for 15 min yielding a small pellet of glycerin. So workup is very easy.

The small amount of glycerin instantly indicated that the most of the oil did NOT convert over to the ester as wished. Using 13C NMR and comparing to authentic samples we could see that the major component was oil with a small (~10% to 15%) amount of FAME. Actually more FAME than I expected so maybe some of the FFA’s were converted over? So it looks like it worked so far.

I suppose the real test will be the behavior of the “pretreated” oil under base conditions? If the FFA’s were indeed converted over to the methyl ester then the base step should be much easier to process. So next is to setup a base catalyzed reaction and see how it behaves.

Sunday, November 13, 2005

Fair oil filtered and ready for reaction/barrels ready for collection.

Brian and I successfully de-gunked and cleaned four collection barrels, and filtered about 300 liters of oil from the Fair. One more session of filtering (there is still at least one more large tote with clear, well-settled oil at the top) and we'll have at least half of a large tote (1000 liters) ready for reaction. Hopefully Asa Gray can haul it to our reaction facility with some help, and that will cover the next several reactions.
Brian and I also washed four barrels, and dumped the gunk from them into a single barrel, so that we can eventually skim more oil from the top, dispose of the water, and use the solid matter to fuel our future oil and scrap burner to heat the oil we filter. I used clear silicone to seal the edge around the bucket on two of the barrels and brought them to my house. I will talk to the restauranteurs that we had courted previously, and get permission to deliver them to them next week. Hopefully we'll be able to convince them to go ahead and break their contracts with the rendering companies and use our drums for oil disposal instead.

Using a galvanized steel bar left over from my fence, we were able to setup a very easy to use filtering setup that went very well. I left a 5 micron filter bag in the 1000 liter tote, as well as the pump, heater and some other equipment. Asa Gray mentioned he might go up to the shop tomorrow or Tuesday, so all of this equipment will be there waiting for whoever goes to filter and prepare oil.
We looked at the totes outside the shop as well and realized that several of them were almost completely water, with only a very thin layer of oil at the top, so we dumped these out in an inconspicuous spot where there was already no grass. Three of the restaurant totes outside were okay, and we filtered these for SVO. (Let's decide what the value of the oil is and we'll put this into the pot.)
Lots of success this weekend! Assuming all goes well with the restaurants this week, we'll have to get more barrels from the shop and deliver them to the additional restaurants. (We currently have four or five that agreed to give us oil, although they haven't seen us since before the fair, and haven't broken their existing grease contracts.)
I'll have a draft of an oil contract for the restaurants and the big suppliers soon.

Monday, November 07, 2005

TOP STORY: WFU Biofuels Project!


Hey all, Check out the article today on our effort in the Winston-Salem Journal. If you can get ahold of the print version, it has a nice graphic about WVO and biodiesel. The article ran front page with a big picture of Jen above the fold. Let's keep up the Big MO!