I have a supplier of waste veg/cooking oil from a chipper. I have used a burco boiler to heat the veg oil and I have connected a pipe to its attached tap to let me draw it off through a filter/pipework set-up. After filtering it through a pair of tights and filter medium I acquired from a new air-conditioning unit I am still getting small particles of debris in the end product and the oil is still nearly black, I was under the illusion that it would run clear after boiling and filtering. I am not going to put this in my 1996 Merc C250diesel as I am afraid it will wreck it.
I have a 2 tank set up, starts on diesel, heats up and a separate fuel tank allows me to burn veg oil with the flick of a switch.
What am I doing wrong?
Should the oil be like new before I use it for driving?
What is the best filter medium to use?
Please help, thanks in advance people!!!
I thought you had to use methanol and lye as additives in the bio diesel distilling process and then filter out excess water moisture content.
May 8th, 2010 at 12:06 am
Sorry to say I can’t help, but there is a company called Nice Fuels in the UK who filter used cooking oil for use as straight vegetable oil fuel for cars. Not sure of their website, but googling should get there.
Otherwise try posting in the forum http://www.ecoboom.co.uk/forum/default.aspx
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May 8th, 2010 at 12:50 am
I thought you had to use methanol and lye as additives in the bio diesel distilling process and then filter out excess water moisture content.
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May 8th, 2010 at 12:57 am
ask here;
http://www.vegetableoildiesel.co.uk/forum/index.php
they lovely people.
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May 8th, 2010 at 1:07 am
The first problem is right there, that tap. It is too probably way too low, you must SIPHON or DRAW OFF the oil from the upper level, or, if you can plug the old hole, and make a new hole 3 inches from the bottom, an angled baffle plate with the lowest point 1/2 an inch from the bottom to shield the tap may help. (use a circular ceramic platter as sold to reheat/bake pizza on, or a terracotta dish as sold for container plants). Use 3 of 1 inch x 1/8" SS bolts, well sealed, these will be put though the boiler housing to effect the angle… two opposite, one lower down. Simply scrape off the muck after each batch or so.
You could also try a high capacity oil filter, fitted after the warming tank, and after any other prefilters you can arrange. Go to your auto shop and ask which have the largest canister. This will require some plumbing mods, but easy if you have a workshop. The filters may also need to be kept warm. (depends on the environment you perform the filtering in)
This prefiltering equiptment is all set up in the garage, or workshop etc, of course.
Tights are useless, they just don’t go fine enough. (but ok for gluggy paint) If you are forced to use low cost mediums, pack them tight into the stage/container, and increase the size of the stage.
What is this mysterious "filter medium" you mentioned? Paper is fine. I used to use those drip coffee filters for all sorts of things, and deep frying oil is usually filtered through these special papers. (they will NOT clean the oil to "as new", to clean the oil you could also try building a 20 litre or so filter canister loaded with course size high surface ratio mineral like limestone chips, or autoclaved cement rubble, etc. With limestone the temp must be monitored, with other heat resistant materials you can heat the raw solidified oil higher.
Your supplier could maybe buy a thermometer for the chip cooker, they may be burning/overheating the oil. (unlikely, but… )
And also try to advise them to change the oil more frequently, primarily for health reasons, but that may make some difference, the longer and hotter the use, and also what you cook will all darken the oil. You could offer a small payment for the waste oil to promote more frequent refreshing of the oil.
Also, try reducing the viscosity of the warmed oil (before the filter stage) by adding 5 to 10% diesel, which may permit solids to descend to the bottom of the warm pre-filter tank faster.
Or maybe build a simple centrifuge to separate the solids. Draw the oil off from upper level.
BTW, reducing the use of ANY internal combustion engine is the best way to reduce emissions, so try to use a bike/walking for short trips. If you have to use a car, (and those city/urban planners have forced us to do so), combine outings so the vehicle runs at optimal operating temperature, cold engines emit more pollutants.
Never operate such plant without adequate safety precautions: well ventilated, fire extinguisher on hand and handy to reach near exit door, a smoke alarm, just to be sure. Keep children away from this operation unless supervised.
Good luck!
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Inventor/engineer/smartass.
Dont DO as i say, please check it out for YOURSELF…, when satisfied, proceed.
May 8th, 2010 at 1:38 am
The veg oil burners that i know use filters borrowed from the maple syrop industry.
I’ve never heard of boiling the oil in the preparation phase, maybe that’s why it’s black.
You might want to go to farm supply and get an inline filter designed for a big diesel tractor to put inbetween your tanks and stock filter. . that will save you having to replace your expensive mercedes filter so often.
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expereince
May 8th, 2010 at 2:18 am
The hydrocarbon chain lengths of diesel fuel averages 11 or 12 carbon atoms. The chain length of pure peanut oil is 18 carbon atoms but the chain length of waste vegetable oil can range as high as 35 carbon atoms. This is because the oil will polymerize under heat, this is why there’s all that gunk on an old frying pan that can’t be cleaned out. Boiling the waste vegetable oil will just cause it to polymerize further and running a modern diesel engine on unprocessed vegetable oil will just mean the engine will irreparably gunk up, essentially everything will just get plugged with plastic and then you might as well just throw the engine away.
You need to cut down the chain length which is why Sodium Hydroxide and Methanol is used in a process called transesterification. Sodium Hydroxide reacts with oils to form glycerides (soap), you don’t actually want soap but you do want to just clip out a center section of a long chain out. Dilution with methanol makes certain that the Sodium Hydroxide is disperse enough that only a short section of a given chain gets "edited" out. The left over pieces are actually esters due to the nature of the reaction hence the process is called transesterification. The glycerides settle to the bottom of the mix leaving a mixture of biodiesel and methanol up on top to be skimmed off. The methanol is corrosive and will eventually damage the engine so you "wash" it out with water, like any alcohol, methanol has an affinity for water and if water is mixed in large enough quantities, the methanol and water will settle out of the mix leaving just pure biodiesel (this is how you tell how much ethanol has been mixed with gasoline, you wash it and see how much ethanol settles out). It takes a fair bit of work to work the water through the mix since water and oil don’t mix, with small batches you can shake and roll the containers about but with large batches, people use those air bubble things for aquariums to keep mixing things up.
With properly transesterified biodiesel, you don’t need to modify your engine at all. It’s really foolish to add heaters, extra tanks and switches just to run a diesel engine on vegetable oil because you know the engine will eventually be ruined and it’s a lot less work to make real biodiesel that doesn’t need any modification to the vehicle. Downside is that you also wind up with a lot of really bad soap to dispose of (the glycerides), people who make biodiesel at home tend to have real clean driveways.
It’s possible to make real synthetic diesel (mostly iso-decane) instead of the ester mix approximation (bio-diesel). This would involve gasifying the oil (anything that burns can be gasified, wood, coal, garbage, dung etc.), gasification is partial burning to produce a mixture of carbon monoxide and hydrogen known as syngas, wood gas, and town gas. Such a mixture if kept with iron or cobalt catalysts under about 10 to 60 bars of pressure and 180 Celsius temperature will polymerize to form C8 through C15 hydrocarbons (diesel) plus heavier waxes which can be hydrocracked back down to diesel. At 300 Celsius, it would form hydrocarbon lengths less than C11 resulting in primarily gasoline and some methane which can be feed back into the gasifier or used to generate electricity. The gasification synthesis (Fischer Tropsch synthesis) route is actually more efficient than the transesterification route but takes a lot more equipment. It does avoid the problem of disposing of all that soap.
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May 8th, 2010 at 3:00 am
i have been using new veg oil from the supermarket, since the price of veg oil is just a few Penny’s lower than the price of diesel you would think this is a wast of time but new veg oil gives better MPG than diesel. I don’t have a workshop or any place i can clean used chip oil but using 50% new oil with 50% diesel gives me much better value, don’t fill your tank with just oil in the cold weather as i did this last winter an had to drain a full tank, made a total mess and also lost a days work to get my car going again but in the long run iv saved a lot of money. Also the smell in traffic jams from using more than a 50 ~ 50 mix can be embarrassing as it creates a right smell!
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