World Famous Dr Pepper Viscosimeter (Pat Pend)
Ladies and gentlemen, I have re-written the instructions for the World Famous Dr Pepper Viscosimeter (Pat Pend) and would appreciate your imput as to clarity of the instructions and whether some parts need re-written to makethem easier to understand.
For the original posting visit This Discussion
World Famous Dr Pepper Viscosimeter (Pat Pend)
The World Famous Dr Pepper Viscosimeter (Pat Pend) is a piece of test equipment which I “developed” several years ago from ideas given to me by the Chemist “Michael (Aus)”.
When using the World Famous Dr Pepper Viscosimeter (Pat Pend) in conjunction with a stop watch and thermometer, it is possible to detect a difference of less than 1% un-reacted oil between two different batches of well washed biodiesel made from identical oil.
Well washed biodiesel will only contain Methyl Esters, Monoglycerides, diglycerides and triglycerides. Of the four, Methyl esters are the least viscous.
Therefore, If you are checking the viscosity of two different batches of well washed biodiesel made from identical oil, the sample of biodiesel with the highest viscosity will contain more un-reacted and partially reacted starting material than the sample with the lower viscosity.
If you do not have access to GC (Gas Chromatography), a Viscosimeter is by far the single most meaningful piece of test equipment you can have when conducting biodiesel experiments.
HOW IT WORKS
By comparing how long it takes for a specific amount of biodiesel to empty from the Dr pepper bottle, we can tell which batch has the higher viscosity. The higher the viscosity, the longer it will take for the specific amount of biodiesel to empty.
CONSTRUCTING THE WORLD FAMOUS DR PEPPER VISCOSIMETER (PAT PEND)
* Empty Dr Pepper Plastic Bottle roughly 1.25 to 1.5 litres in size.
* 1 Piece 2.5 cm (1 inch) length of copper tube of approximately 5 mm Outside diameter and 2 mm Inside diameter.
* Flat piece of wood approximately 45cm (18 inches) long, 7cm (3 inches) wide and 1 cm (5/16 inch) thick.
1. Cut the bottom off the Dr Pepper Bottle.
2. Remove the screw-on-top and drill a hole in it so that the length of copper tube is a tight fit through the hole.
3. Make sure the ends of the Copper tube are smooth and round with no burrs
4. Push the Copper tube half way through the hole in the top.
5. Drill a hole at one end of the flat piece of wood so that the screw-on-top of the Dr Pepper Bottle fits in it very snugly when the top is screwed onto the bottle.
You are now finished constructing the viscosimeter.
The total cost will be something under a dollar.
GETTING READY TO USE THE VISCOSIMETER
1. Screw the top tightly onto the bottle.
2. Use a sharp item to scribe a fine line about 5 cm (2 Inches) down from the bottle top on the bottle (Known as the “bottom” or “finish” line).
3. Hold the bottle with the top down.
4. Put your finger over the outlet of the tube.
5. Pour about 700ml water into the bottle (Remember you cut the bottom off the bottle).
6. Check to make sure no water leaks from the bottle around the top or tube.
7. Scribe a second line (Known as the “Top” or “Start” line) directly above the first line at the lever of the water.
8. Remove all water from Dr Pepper Bottle.
9. Push Bottle Top into hole in board so that the Dr Pepper bottle is perpendicular to the board with the bottom of the bottle up.
10. Place board on table so that Dr Pepper bottle extends past the edge of table with tube pointing down.
11. Place heavy weight on other end of board.
You are ready to start comparing viscosities.
USING THE WORLD FAMOUS DR PEPPER VISCOSIMETER (PAT PEND)
1. Make sure the samples being compared are well washed so there are no contaminants in the sample.
2. Viscosity is highly affected by temperature. Make sure the samples being compared are at identical temperatures. A lower temperature is probably better because it slows things down and gives slightly increased run-times. Room temperature is easiest to maintain.
3. Place finger over end of tube.
4. Fill Viscosimeter so that oil is above the “Start line”.
5. Place container under viscosimeter to catch the oil as it runs out.
6. Remove finger from end of tube.
7. Watch carefully, and at the exact instant the level of the oil crosses the “Start Line” start your stop watch.
8. Watch carefully, and at the instant the level of the oil crosses the “Finish Line” stop the stop watch.
9. Write Down "run time".
10. Check the Temperature and do two more viscosity runs with the same oil.
11. Be amazed at how consistent these times are (normally within one or two tenths of a second).
12. Clean and dry inside of viscosimeter.
Do the same thing with the next sample of well washed biodiesel.
If the two samples of biodiesel were made from identical oil, the sample of biodiesel with the highest run-time contains the most un-reacted and partially reacted starting material.
The greater the difference in run-times, the greater the amount of un-reacted and partially reacted material present.
CALIBRATING THE VISCOSIMETER
1. Add 8ml of un-reacted oil that the test batches were made from to 800ml of the lowest viscosity sample tested.
2. Measure the viscosity run time as described above and write it down.
3. You will see a slight increase in run-time. This difference in runtime is the difference an increase of 1% un-reacted triglycerides causes in the biodiesel sample.
4. Add another 8ml of unreacted oil to the sample and check it's run time.
You should notice a further increase in run time.
5. This difference in runtime is the difference an increase of 2% un-reacted triglycerides causes in the biodiesel sample.
6. Add a further 24ml un-reacted oil and check it's run time. This difference in runtime is the difference an increase of 5% un-reacted triglycerides causes in the biodiesel sample.
Mon 24 Jan 2005
Checking conversion of biodiesel to ASTM standard?
After my recent heated discussions about the validity of viscosity testing with "Kalib", Neutral has written the following information about home viscosity testing of biodiesel"
"Perhaps this is a good moment to remind ourselves how to use viscosity to determine conversion to an accuracy more than sufficient for the home brewer.
As viscosity is only a comparative tool first you need a reference. This can be prepared by treating a sample of the oil in question with 7g NaOH plus titration in 300ml methanol per litre of oil, stirring for one hour at 55deg C. This will produce a sample of such high conversion that the remaining glycerides are negligible.
All samples must be washed and dried to eliminate errors due to methanol content.
The high conversion sample is divided into a number of parts and to each part is added a known proportion of the original oil, say 1%, 2%, 4%, 8%.
The viscosity of all samples are now compared and by reference to the series of standards the conversion of the original batch can be estimated. At about 1.5% triglyceride the batch will make ASTM."
I usually work with just one sample, adding the un-reacted oil and measuring the viscosity one step at a time.
Rev Tilly KEThis message has been edited. Last edited by: Tilly,
Dr Tilly, please check your Diego Garcia bank account for the obligatory commission. These instruction are clear as well-aged biodiesel. I am going to use my Land Rover brake lines for the outflow pipe - L/R brakes never did work much anyway.
A picture is worth a thousand words. I understand the description, but a picture may be useful to others who don't have the lab experience some of us do. Use the paper clip icon on the right of the menu bar to post one. Be kind to the board, however, and make sure the pic is 640 by 480 pixels or less. My first attempt was huge! I just love our new picture posting ability. Blessings. Joe
Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
The only comment I would make regarding this very careful plan is that as we are only comparing samples the actual temperature is not important. What is important is that all samples be at the same temperature as viscosity is highly affected by temperature. The safest temp to use is room temperature. Any attempt to operate at some other temp runs the risk of temperature drift.
I also enjoyed reading about the operator placing his finger over the outlet, filling the vessel, then finding that he needed a container to catch the output!
mmh, Joe_M and neutral, thank you for your coments
Yet another clear and useful tool for the biodiesel community, thank you.
At the risk of being pedantic, I wondered if you or maybe neutral could relate this directly in some way to the ASTM or EN14214 fuel specs for biodiesel.
The European one EN14214 can be found on the last page of the following pdf file
The limit on monodiglycerides is 0.8%
on diglycerides 0.2%
on triglycerides 0.2%
on free glycerine 0.020%
on total glycerine 0.25%
To get a really well reacted sample of the same batch being tested would you recommend a Dr Pepper biodiesel batch with maybe a second stage, to be sure of a complete reaction.
Drifter, I do not think there is a relation to the standards.
You need GC for that.
I think your idea has merit. If you use a two stage reaction with ample methanol the conversion will be very close to complete. If this is used as the reference material and if 1% unreacted starting material can be detected, as Tilly says is possible, I think you would have a good indication of whether your batch met the ASTM standard.
This is a pretty interesting topic when you look at closely. The ASTM standard only sets a limit on the total glycerol, free and combined, of 0.24%. If this was all contained in triglyceride it would be equivalent to about 1.9%. If all diglyceride, about 1.3%. If all monoglyceride, about 0.7%. In reality it will be a mixture of all three so the German limit of glycerides, which totals 1.2%, looks pretty consistent with their total combined glycerol of 0.23%. Whether or not a simple viscosity test could pick this up would depend on how the compostion finished up. If the main component was triglyceride I think it could be done but if the main component was monoglyceride I would doubt it. I suspect that the final composition depends on how the reaction is done. If the progress of the reaction is limited by time it might favour the triglyceride residue, but if limited by amount of methanol it might favour the monoglycerides. Does anyone have info on this?This message has been edited. Last edited by: neutral,
If one wanted to increase the time differential and thus the degree of accuracy so that 1% unreacted oil caused a 3+ second increase in time, presumably that can be done by running 5 liter batches or using a smaller orifice?
neutral, I am trying to form a coherent question concerning "normalicy", which I will post under the Acid Esterification heading soon.
I hope you will keep an eye out for it.
The best way to achieve good repeatability in the viscosity comparison is to have both the upper and lower marks on narrow sections of the vessel while the bulk of the vessel between the marks is wider. Ideally the restriction would be some distance below the lower mark so that the head, and hence the flow rate, would be fairly uniform throughout the run. Something in the shape of a large pipette with a mark both above and below the bulb would be good.This message has been edited. Last edited by: neutral,
Sensei Neutral San (and Tirry San of coulse)
Good Viscomiter would have shape of one of the Seven Gods, Hote (with accent ovel e) plonounce Hotai; Vely fat in the middre, with smarr hole at top and bottom.
To arr Jews, May you have Sacled Passover today.
Without ancestors what are we?
Imagine 7 generations of chirdren without parents.
This message was not edited by Oko San
"Once we meet and talk, we are brothers and sisters.» Okinawan ProverbThis message has been edited. Last edited by: Kenito Oko,
Sorry Tilly but I fail to see the relevance of measuring oils against oils, or BD against BD.
If the idea is to run a Diesel engine on the stuff shouldn’t you be comparing your finished product with petro diesel?
Have you established a Benchmark/Datum of some sort in the past?. If so I can’t find it.
Dhill, I measure biodiesel against biodiesel to determine which production procedure makes better biodiesel.
As an example, on the odd occassion that the Foolproof method actually makes biodiesel, the viscosimeter showed that the Foolproof biodiesel was of very low quality when compared to biodiesel made using the Tidball/Fox FATTA Acid/Base method.
I measured biodiesel against kerosene once and was surprised at how close their viscosities were.
Rev Tilly KE
This is Kalib.
Tilly thought it would be a good idea to libel me, and then email me personally so I could tell you why he would be so intent on attacking someone with clear logic. Read on & judge for yourselves.
I've included my remarks discussing why I think that Tilly's claim that "Viscosity is the best home test for biodiesel quality," is misleading.
Hope this helps, I'd be glad to respond to questions.
originally posted on biodiesel@yahoogroups list, 2005
I take issue with claims such as
Once again, let me stress:
The Dr Pepper Viscosimeter is far and away the best biodiesel home quality testing device I have run into.
Devise your experiments in the correct way and you can very accuratly test almost anything, just not to GC standards..
since there really are too many variables going on here to tell you much of anything (temperature, time, equipment, feedstock viscosity, contamination with liquids of various viscosities, etc). As a qualitative test which gives you relative results, that is, it tells you whether the viscosity of the fuel you made today is the same or different than the fuel you made yesterday, sure it might be called "good." BUT it is misleading to continuing hammering the statement over and over again, without qualifying what it tests and it's limits. Test almost anything, eh? And "just not to GC standards?" Not even close, I'm afraid.
IT IS NOT A GOOD TEST for evaluating the completion of a reaction. Why do I say this? Because given that other tests (Reprocess Test comes to mind) actually probe whether there are any molecules that will transesterify or not, it makes obsolete any test that less directly investigates these variables (namely viscosity).
Also, if you mixed the right amount of an oily alcohol (like isopropyl) with the right proportion of veggie oil, you can probably come up with a mixture that has a viscosity of biodiesel that you'd expect. And if you can't distinguish biodiesel from alcohol and oil, then what good is it really?
The best device I have come up with for testing the completion of a reaction is a jar with a good lid, and some lye and some methanol. Requiring skill doesn't make a good test; on the contrary in many cases. And if people are going to make claims that there has been validation tests done with GCs, let's see the chromatograms and the methods used.
I think that those preparing to correlate home tests with GC results are on the right track there... doing all the tests that we are familiar with & easy enough to do at home and then seeing what sorts of results the GC gives.
If tests and results from those tests -- I'm open to any tests at this point -- can be QUANTITATIVELY and REPRODUCIBLY correlated to quality fuel (ASTM, DIN, or EU specs are some examples of what constitues quality fuels) then we have a winner. As far as I know, no test is delivering this to the home-brew community, however there are some good candidates.
Interestingly, it seems that certain vehicles' systems are much more sensitive to bound glycerine than I would have guessed, given the recent discussion on the biodieselbasics@yahoogroups list(?). I am still getting myself organized, having joined a bunch of new lists, a few weeks ago.
So my effort to focus on which test may be the most critical has looped me back to where we were a few days ago. it's becoming clearer to me, too, that we need to correlate home-brew "shade tree" tests, existing or new, with specifications like those in ASTM 6751.
Although I am a trained scientist, I don't pretend that my backyard is a lab. Though I take care in what I do, I don't expect to be able to probe and question in the same way that I would if I had access to the more expensive equipment. So what do I do? Like many of you, I take advantage of the tools I have and draw some inferences from what happens. I've hoped but never assumed that what I'm making is ASTM spec fuel... and perhaps it's a bit of a block thinking like that, but since I haven't had access to the equipment that I know will really do the job, I've just brushed a lot of stuff under the rug and crossed my fingers.
There are reasons that industry uses the tests they do -- they are specific and illustrative. Though I reserve some optimism for the yet explored possibilities, my hunch is that it is going to be difficult to correlate any of the tests that we are familiar with to tests with the precision of a GC. Particularly, I'm guessing it will be difficult to see the difference between "pass" and "fail". Which means, perhaps, we'll all have to learn how to make home-made GCs. (that's my sense of humor)
In this case, these specifications are not just for the sake of red tape or to satisfy someone's ego, ASTM 6751 actually defines what quality is to the ASTM, in terms that are very difficult to argue with, i.e. virtually free of water, glycerol, other contaminants, etc. Just in case it's unclear to anyone out there. Regardless that it's a legal definition, it's pretty well thought out, even if it does have that arguably inappropriate distillation curve item.
I'd like Tilly to define what quality is to him, because I think he uses a circular definition. He uses his viscosity tests as the basis for his idea of quality, as far as I can tell, and really what does that say? He then refers to some GC tests done by someone else that isn't speaking up to represent them as some sort of vague validation of his test. And we've already seen that levels of 1% contamination of triglycerides hardly gives a significantly different result in his own tests. 1% is huge in the context of what we're talking about. What's your limit of detection? In other words, when can you no longer distinguish the viscosities of 2 samples? I bet it's nowhere close to 0.24%. And if it is, then well, we can all stop looking for a shade tree test to use. We just have to do some calibration.
Sorry that I haven't more specifically responded to your posts above, but it's all been said in our back-and-forth on yahoogroups.
And, Tilly, try not to make remarks about people if you don't have some sort of actual experience with them to back it up, please. Is it really necessary to be so rude? My experiments run quite smoothly, and if some insight I provide helps someone seeking the truth, then cool. I don't sugarcoat and I don't oversimplify.
Southern California Biodiesel Research & Development
Very glib Kalib mu biodiesel friend.
It is clear from your post that you have failed to appreciate the basic assumptions for the Viscosity test when using it to measure glycerides in BioD. Hence your rubbishing of it, first at Yahoo and now here. Forgive me for the observation that your atitude is anything but scientific. To correct this I recommend you ask "how is it done" rather than the "I'm a qualified idiot and I say it can't be done"
Unfortuneately I am left with the thought that you are more interested in atacking a member of this forum for your own ends, whateverthey be, than contributing to our wde discussiopn here...
however when I get time I am going to post another thread on yahoo with the details of how it is done to the best of ones ability and we can chaat about it, scientist to scientis, if thats what you really are...
I will remind you, Mr Bushpig, that I am responding to an attack, and if I didn't think that contributing to a dialogue about biodiesel quality wasn't important, then I would be doing something else.
I think I have to make yet another correction to your characterization of what I've said. I don't think I ever said that "it couldn't be done." And I understand the basic assumptions, and, I ask, how is it going to tell you anything than, "oh, I made biodiesel better (or worse), this week"?
We can argue about definitions of science and of quality, all day. All I know is that I've helped a lot of people figure out little problems they've had with homebrewing, and it's because I methodically apply first principles and my personal experience with materials. I wasn't trying to negate Tilly's method so much as to raise some questions to the forum that he wasn't directly facing, pointing out that it doesn't do some of the things he claims (and then has retracted, btw). All of this is in the biodiesel@yahoogroups archive.
And the last thing I'd like to say here, is that I do think it will tell you something, but without a way to objectively calibrate it, it's not the "best" test. It's another test and one that would well be put to use alongside the wash test, reprocess test, titrations, etc.
Southern California Biodiesel Research & Development
Hello Kaloib, who was attacking you?
I thought you were just rubbishing the validity of viscosity testing.
I am glad yo have helped lots of people figure out little problems they have with home brewing.
Which things have I "retracted btw".
At times You seem to struggle with reality.
Rev Tilly KE (Actor)This message has been edited. Last edited by: Tilly,
Mr bushpig? dear dear dearie me; I'll get all pretencious if you keep that up...
Kalib you may have to expand your horizions here at infopop. We have long go accepted that viscosity testing is the best backyard test Unless you have a GC...
Kalib, the method of calibration has been set out in detail recently. Didn't you notice it? Previously it had been assumed that the calibration method could easily be worked from first principles by anyone following the discussion.
Kalib, I recently came into possession of a book called A Petroleum Handbook written by employees of the Dutch Shell Company and published in 1938. At that time chromatography was liquid through filter paper and done in those big square jars which made such good terrariums in the 80's; if you're old enough to remember.
In the section on "Fuels for Compression Ignition Engines" the fuels are defined IN TERMS OF VISCOSITY..... eg "steam raising boilers employ fuels of 200-1,500 seconds Redwood I viscosity at 100F" and "slow speed engines mostly use the so-called diesel fuels, which have viscosities in the range of 40-100 seconds Redwood I at 100F" and so on....
In "The testing of fuels for CI engines" the viscosity is considered, on my interpretation, to be the most important amoung the tests that could be carried out in the lab out of those specified for it eg., Specific gravity was said to "have no direct connection with the suitability of a fuel" ....
Kalib if you came to have a shot, now's the time to depart, if not, then join us in our common purpose....
I ask you, surely if the viscosity was the most important test of a fuel before the invention of the GC; it must now be the best backyard test available....?
The book refers frequently to the American Society for Testing Materials - ATSM so at least now I know what it stands for...
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