|12 forum posts|
Some 60 years ago my Father and I built a Stuart Turner 10H engine and ran it from a Stuart Turner 500 Babcock boiler, To fire the boiler we made a very crude spirit burner.
It is about thirty years since I last had it running and I would like to run it again. The engine and boiler have been carefully packed away and the engine spins over freely.
To replace that crude design I intend to make a new burner. Apart from the threads about spirit burners on this site I have looked at **LINK** which have given me ideas on how to construct a burner. I have also looked at **LINK** which has an interesting idea for a wick.
What I haven't been able to find is how to calculate the size of the burner(s) and how much spirit is burnt in a given period.
Can anybody give me pointers to how to size the burner and the reservoir to give a running time of, say, 15 minutes.
Another question relates to Meths; from what I have read shop bought meths is unreliable. I do have some 99% pure industrial alcohol which is highly flammable. Has anybody have experience of using alcohol as fuel?
Thanks for any help.
|not done it yet||18/04/2019 08:07:58|
|2803 forum posts|
Meths is simply denatured alcohol. 96% will likely be the best attainable. Cheaper supplies may contain more water?
I doubt that 99% industrial alcohol is particularly any more flammable than meths. Ethyl alcohol at 100% proof was flammable back in the old naval days when that was the test for unadulterated rum rations. 100% proof, then, is about 55%ABV now, I think, although the actual numbers changed a bit at some time.
|371 forum posts|
Originals and accurate repro ones of the original come up on ebay from time to time.
I got the measurements for mine from the chap and made my own.
Alternatively, you could consider the bix gas burner which is cleaner and more controllable.
|4083 forum posts|
Denatured alcohol, of which one example is 'Meths', is any of several similar mixtures designed to put people off drinking the stuff whilst also making it hard to purify for recreational purposes. There are several industrial variants, but we're talking about domestic mixtures.
In modern times UK Meths was roughly 90% Ethanol and 10% Methanol (or a substitute), plus small quantities of crude Pyridene (a nasty tasting 'adversent' ), light mineral oil (an emetic), and Blue dye - Methyl Violet. European Meths is about 94% Ethanol, 3% Methyl Ethyl Ketone and 3% Isopropyl Alcohol plus Denatonium Benzoate and Methyl Violet dye. Neither contains water and the heat values are very similar. Euro-meths has a few advantages over UK-meths in that it tastes nastier, makes it harder for criminals to extract the Ethanol, is slightly more stable in storage, and less toxic. Elsewhere in the world and industrially denatured alcohols may well be different, including the possibility they include water.
In Europe, it's possible that some Methylated Spirit is watered down fraudulently in the same way horse meat and worse ended up in our dinners recently. More likely though that watery Meths picked it up naturally during manufacture and storage. Ethanol is very hygroscopic - left to its own devices it will eventually absorb (roughly) its own weight in water. The drying effect is useful - I often use Meths to quickly and thoroughly dry water washed workshop items. Anyway, once the cap has been removed, and perhaps before, Meths starts absorbing water. How fast varies enormously depending on the seal and the temperature and humidity, which is why some chaps can tell you from experience that Meths is rubbish, whilst others never have a problem with it.
I wouldn't worry about fresh shop-bought Meths being 'unreliable' and it's much easier to buy than Industrial Alcohol.
In theory the wick size needed to drive a boiler could be calculated because the heat value of the fuel is known as is the amount of heat needed to make a given weight of steam. Unfortunately the boiler efficiency, steam pressure, engine demand, and rate fuel moves through whatever wick material you have are all unknown, as is the efficiency of the burner. The answer could be determined by experiment but I think it would be easier to copy what someone else has already proven to work. The copy only needs to be of similar size and layout.
Bill mentioned BIX burners. I'd not heard of them before, but they look like a really good answer to this problem because their heat output can be controlled in a way spirit burners can't. They replace the need to experiment or copy with a burner that can be manually adjusted to produce whatever heat happens to be needed by a particular boiler / engine.
Edited By SillyOldDuffer on 18/04/2019 12:14:16
|not done it yet||18/04/2019 12:46:15|
|2803 forum posts|
If the alcohol is derived by distillation, one cannot achieve better than 96% - as that is a constant boiling mixture for water and ethyl alcohol. There are chemical ways of drying it further or, alternatively, synthesising it by other chemical methods.
Best we can get is about 25% alcohol by fermentation (the yeast will be killed off in higher concentrations). Then we need to distil the mixture, under reflux, to attain high alcohol mixtures. An ordinary still, without reflux, can just about achieve 90% at best, 85% being more typical, but efficiency falls off quite sharply.
|371 forum posts|
Should have said Forest Classics are the people for BIX burners.
Round and rectangular in various sizes plus the supply jets, pipes and gas tanks.
All on their website.
|4083 forum posts|
True, but I think all Ethanol made by fermentation for use as a fuel is dried out. On a large-scale water used to be removed by distilling with Benzene, which pushed the cost up. Now demand for Ethanol is high because it's mixed with Petrol they've researched and mostly switched to a cheaper method. Surprisingly to me, who was told in my youth it was impossible, the water is filtered out with a sieve! Apparently micro-sieves are readily available today that can pass water molecules while remaining impervious to Ethanol. Distillation and chemicals aren't used at all.
Apart from Maths I'm starting to believe that everything I was taught at school was wrong!
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.