Hi all, While browsing the library of the Technical University of Delft (Netherlands) for any Primus related articles, I stumbled on this one. I actually found many more very interesting articles on stove efficiency, using stoves on hight alitutudes and the hazards of using kerosene stoves. I am not sure if I can post all this because of any copyright related issues. This article, however, I found on several other websites. I thought it would be ok. I converted the PDF to JPEG. If you want the original or the other articles PM me. Jacob
@JacobLotz As you've indicated, it's something that I've seen elsewhere at one of those other sources you spoke of. The thing I remember was the frustration I felt first time around and have experienced again now, that the authors were vague in describing how they'd modified the burner to vapourise waste cooking oil fuel and that the modifications didn't appear in photographs - "Spray nozzle exit angle modified" they say?? The photograph of the stove fired up shows a burner that looks on the verge of failing to vapourise the fuel. Certainly my experiments with fuel/burners/caps/jet sizes have often resulted in the phenomenon of good combustion immediately after priming the burner, degrading to a failure to vapourise the fuel when the temperature spike of the priming charge has tailed off. Their burner looks like one that's about to do that. Supposing that vapourisation could be maintained on cooking oil, the authors fail to identify the potential issue of rapid clogging of the burner with the greater coke deposits likely to arise from the fuel compared with kerosene. The consequent unreliability and maintenance burden faced by poor households dependant on the stove as their primary resource for cooking would surely be offset by the possible savings of using a cheaper fuel. Still, I hope their dissertation got them A's for effort! John
Ive seen people who make bio diesel from waste cooking oil, although it requires a mixing and refinement. Other than suggesting a relatively higher pumping pressure of 28 psi or 1.8 bar, Doesn't appear the orifice would atomize raw oil to burn cleaner than it suggest. If I'm not mistaken Germany in WWII was producing bio diesel from vegetable oil due to demands of fuel. Anyways, thought that interesting when fueling up at a high cost when Brazil could provide sugar Cain fuel for super cheap. Ren
It actually requires more than just 'mixing and refinement'. To make biodiesel from vegetable oil, the triglycerides (the 'oil') need to be saponified to fatty acids and glycerol, and the fatty acids subsequently esterified with methanol. This can be done in a single step (transesterification), but that would be more 'difficult' in a 'home lab' environment, and would still require removal of the glycerol. But in principle, it is something that is doable on an amateur level.
I had a dig around a few years ago into bio diesel for stoves, there are techniques for production at home using non transesterfication methods but probably the results only useful in engine applications. There are probably too many remaining clogging stuff in this process for use in even a modified vaporiser/burner. I have tried a small paraffin veg oil mix but it very quickly clogged. I'll try and find the link again. Even commercial bio diesel is only about 20℅ bio derived I understand. ETA TE requires you to get rid of both the chemicals used in the process and the resulting soap residue
B 20 can be run in Diesel engines with all but no modifications, to use a higher level, such as B 50, B 85 or B100, there has to be more adjustments made. As a rule, the highest you'd see is B 95, the 5% fossil fuel diesel combats the growth of moss or fungus in the fuel, so I've been told. Murph
It is my understanding - though I could be wrong - that 'biodiesel', at least in Europe, is basically defined as fatty acid methyl esters. Can't think of any other way of producing FAME from cooking oil than either saponification followed by esterification or direct transesterification. My main exposure to 'biodiesel theory' is from providing chemicals regulatory consulting support to a company involved in developing a biodiesel industry from Jatropha oil - note that our support was in chemicals registration / toxicology support, not biodiesel technology. It IS possible to run diesel engines on untransformed vegetable oil (heck, like the original jet engine, the original diesel engine - the large stationary engine designed by Rudolf Diesel, primarily as a Carnot cycle engine - was designed to run on anything combustible; originally coal dust), but modern car diesel engines do not really like that - I think in practice mixing a minor fraction vegetable oil with mineral diesel is all you can hope for. A side effect of this is a diesel engine car that really smells like a deep fryer on wheels... As already mentioned, I would think that a vaporizing jet burner (optimus/primus camp stove, petromax pressure lantern) would gum up in no time from the oil polymerizing in the preheater loops.
I know the process includes treating the oil with caustic soda and letting it sit for a while then mixing with methanol. Then its just a matter of recovering excess methanol and filtering out the lumps. I know one person that ran an Isuzu diesel 4x4 on a home brew biodiesel for a few years. People always got the munchies following him. It still eventually clogged his fuel pump. Someone else I used to know went the other way in USA with an Isuzu powered 4x4 that ran plain heated vegetable oil. I lost track of him. I cant see either option producing viable stove fuel
Yeah, that is saponification, followed by esterification. I'd guess though that by doing it this way (in situ) would result in a rather 'dirty' product, even after: I think that a camp stove would run fine on pure fatty acid methyl esters, provided the fatty acids have the correct chain length and are fully saturated - I'm guessing here that a lauric acid-rich oil (aka coconut oil ;-) ) would probably be spot on as starting material. This of course would require a process that includes a fairly effective cleanup, not something that one could easily do in a homebrew setup...
http://lowcdirectory.lowcvp.org.uk/company,bio-powerukltd_6686.htm These were the group I was thinking of, altbough their website doesn't seem to be active any longer. journeytoforever are another area for advice on homebrew bio methods.
