Biodiesel Lab Report

[OMCUSNR]

this is a bump.

Did we have a chance to get lab results??

Thanks

[Wapitibill]

Thanks for the reminder. The test results came back last week but I've been a little busy lately.

First, a little background. The tests as performed by the state are NOT full-blown 'forensic style' chemical analysis. Rather they are done to determine if the fuel sample in question meets all the legally-mandated specs required of it. The state petroleum inspection department, established in the 1870's, is an early example of 'consumer protection' legislation. Before, you didn't knew for sure what you were putting in your kerosene lamp. A lot of people died and a lot of property was destroyed in fires caused by all sorts of nasty liquids that were palmed off as lamp oil.

The test on my homebrew bio-d was done by buddy's boss. As you probably noticed he gave a great 'clinical' description of my dubious product in addition to the numbers. The test on the commercial bio-d was an after-hours project done by my buddy himself. Although he ran the same tests, please keep in mind that he isn't as good with words as his boss is.

Like all samples, the commercial biodiesel sample was stored overnight in a freezer. At 18 deg. F, the sample was jelled. It thawed out with no percepitates evident. The thawed product was clear (meaning no particles, clouding or haze) and bright.

API specific gravity: 28.4
Flash point: =>300 deg. F. (Note: not considered a hazardous product!)
Sulfur: 0.0073%
Calculated Cetane: 45.6

Volume Distillation Rate Distillation Temp.
IBP* 575.6 seconds 301.6 deg. F.
5% 24.2 seconds 615.4 deg. F.
10% 3.4 ml/min 624.6 deg. F.
15% 5.7 ml/min 626.0 deg. F.
20% 5.4 ml/min 627.1 deg. F.
30% 4.6 ml/min 628.2 deg. F.
40% 4.6 ml/min 629.1 deg. F.
50% 4.5 ml/min 630.1 deg. F.
60% 4.6 ml/min 631.4 deg. F.
70% 4.2 ml/min 633.0 deg. F.
80% 4.5 ml/min 635.7 deg. F.
85% 4.2 ml/min 638.4 deg. F.
90% 3.8 ml/min 644.5 deg F.

*(IBP = Initial Boiling Point)

The commercial biodiesel did not leave any of the thick goo that was left behind in the labware by my home-made biodiesel. (Washing? Better control over the transesterification process?) As you'll notice the most of the product boiled off in a nice, even rate between 615 and 644 degrees F. This flat curve shows that biodiesel is a very consistant product.


For reference, here are the test results for a typical sample of #2 diesel as it comes from the pipeline.

API specific gravity: 30.2
Flash Point: 172.0
Sulfur: .0208
Calculated Cetane: 41.1

Volume Distillation Rate Distillation Temp.
IBP 436.8 sec. 324.5 deg. F.
5% 69.0 sec. 410.4 deg. F.
10% 4.6 ml/sec. 429.6 deg. F.
15% 4.7 ml/sec. 445.3 deg. F.
20% 4.7 ml/sec. 458.2 deg. F.
30% 4.6 ml/sec. 478.6 deg. F.
40% 4.5 ml/sec. 498.9 deg. F.
50% 4.4 ml/sec. 519.4 deg. F.
60% 4.5 ml/sec. 540.5 deg. F.
70% 4.3 ml/sec. 564.3 deg. F.
80% 4.5 ml/sec. 591.4 deg. F.
85% 4.1 ml/sec. 608.5 deg. F.
90% 4.1 ml/sec. 630.9 deg. F.

You'll notice that petroleum diesel starts boiling 324.5 deg. F., then not much happens until it gets to 410.4 deg. F. After that it boils out over a 200 deg. spread. A far wider range that biodiesel. The engine might not make full energy use of the higher end (boils earlier) components.

For a good description of the petroleum test procedure, check here.
http://oil.cdle.state.co.us/OIL/Tech...nd%20Specs.asp

[OMCUSNR]

Thanks Bill,

It looks like I'm getting a pretty good product. I bet the difference is in both in the wash, and the methoxide mix (lye quantity). They probablly can hold temps more stable in the commercial process. I'm also pretty sure that this is made w/ virgin oil, no recycles.

I think biodiesel is the way to go for this country. It could eliminate so much polution & put a real kink in funding terrorism, if we could just get the price down to compete w/ petro.

Good luck w/ your home made venture (all of you!)

[Dave Whitmer]

Did you tests also include heating value? After all, heat is the whole point of fuel.

[girlmark]

The distillation curve test is irrelevant for biodiesel (I'm quoting Iowa State university researchers here). Whaen it is applied to biodiesel (see below), its as a holdout from what the petroleum industry is used to when describing fuels (biodiesel chemistry/engineering is more similar to the oleochemical field than the petrochemical field, but petrochemical engineers dominate the fuels industry for obvious reasons)

Distillation curve is a test that you have to do for petroleum because it is a way to describe the exact chemicals that make up the petrodiesel mixture. Petroleum products can be made of hundreds (I think, or at least dozens) of compounds, and that test exists to tell you what exactly is it that you have in your petrodiesel. It's a way of chemically describing an otherwise rather random mixture that results from the complex process of producing petroleum diesel.

Biodiesel has a simpler composition than petrodiesel. It usually contains a maximum of about 10 different types of biodiesels, based on their fatty acids composition (compared to the many more compounds that can be found in the petrodiesel fraction coming out of a refinery), and those 10 or so fatty acid methyl esters are all the variation you'll find from one biodiesel to another. They all work well in a diesel engine, unlike the different components of petrodiesel of which there are some undesirable fractions.

The reason that 'distillation curve tests' do not work easily for biodiesel , is that all of those fatty acid biodiesels have a similar boiling point (in petrodiesel the boiling points of the compounds tend to be further apart) and also that the boiling point of the possible biodiesels is very very similar to the point at which they all decompose (again, very different situation for petrodiesel compounds). So chemists who are used to working with petroleum diesel where this test is done, are confused about what they are seeing.

The distillation curve is one of the tests that was added to the ASTM D-6751 (biodiesel spec) spec by a member of the petroleum industry who refused to back down on the need for this, though others on the committee didn't agree that it belonged on there. It adds an unneccessary expense to the tests done on commercial biodiesel (it's not easy to do theconventional way) and including it in the ASTM tests was a political move which has been used against us in some legal red tape I don't even want to get into.

Obviously in unwashed homebrew there is some other stuff (soap and glycerol and catalyst) that shouldn't be expected in commercial biodiesel. Regardless of what kind of biodiesel you are testing, though, if you do the distillation curve test, you have to do it under vacuum (not normal) which the lab may or may not expect, and to really control the temperature and watch for all of those different fatty acids to come off the apparatus almost at once. Their boiling points are really close.