[Stoves] The PROTOS Plant Oil Cooker

Tue May 1 22:12:44 CDT 2007

When peter and I talked about oil-water emulsion, we were thinking of stoves
and not an internal combustion engine.
Has anybody tried to make a wick stove using vegetable oil? We tried the
kerosene wick stove with vegetable oil, but discovered that vegetable oil
would not rise up the wicks.
Yours
A.D.Karve

----- Original Message -----
From: Keith Addison <keith at journeytoforever.org>
To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>
Sent: Tuesday, May 01, 2007 7:42 PM
Subject: Re: [Stoves] The PROTOS Plant Oil Cooker

> Hello A.D., Peter
>
> >Dear Peter,
> >In Indian cookery, deep-frying in boiling vegetable oil is quite common.
The
> >temperature of boiling oil is 250 C. I have never observed the oil
getting
> >pyrolysed into carbon and volatile matter at that temperature, even when
the
> >same oil is used again and again, as is often done here.  However, your
> >suggestion of using a water-oil emulsion is interesting and worth trying.
> >Have you any suggestions as to how one forms a stable emulsion of water
and
> >oil?
>
> If you talk about water in diesel fuel all the diesel buffs yell
> "Aarghh!" But addition of water to the diesel process decreases
> combustion temperatures and lowers NOx emissions, and a lot of work
> is being done with water-fuel emulsions, with some big names
> involved..
>
> What works with emulsifying petroleum diesel fuel might also work
> with vegetable oil, or at least indicate a direction
>
> Try a search for "Fuel Emulsions" here, to give you an idea (though
> technical information requires a subscription):
> http://www.dieselnet.com/search
> Site Search
>
> There's also this:
> http://www.epa.gov/otaq/models/analysis/emulsion/emulbibl.pdf
> Bibliography of Water-Fuel Emulsions Studies, October 11, 2001, U.S.
> Environmental Protection Agency, Office of Transportation and Air
> Quality. Following is a list of studies that are being considered for
> inclusion in work being done by EPA to assess the effects of
> water-fuel emulsions on emissions of oxides of nitrogen (NOx),
> hydrocarbons (HC), and particulate matter (PM).
>
> This is from dieselnet.com:
>
> "In emulsion systems, water is mixed with diesel fuel and the mixture
> is supplied through one injection nozzle. Depending on the method of
> mixing, either phase can be dispersed in the other. As mentioned
> before, in order to minimize water contact with internal engine
> surfaces, diesel fuel should form the continuous phase in which water
> should be dispersed in the form of small droplets. Water-in-fuel
> emulsions will also minimize the potential corrosion problems in the
> fuel system. Due to the differences in density and other physical
> properties, water-fuel emulsions are not stable. ... Unstabilized
> emulsions separate quickly and must be prepared on-line in the engine
> fuel injection system immediately before the injection. This type of
> system involves two tanks, one for fuel, another for water, followed
> by two pumps and a mixing device. In one laboratory study, mixing was
> carried out as a two stage process [De Vita 1989]. First, the liquids
> were mixed in a premixer, where the internal phase (water) was
> injected through nozzles into the continuous phase (fuel) swirling
> through a cylindrical chamber. The mixture was then fed, through a
> gear pump, to an emulsifier. The emulsifier was a static mixing
> device featuring a system of nozzles and channels, where the blend
> drops dimensions were decreased due to jet diffraction, impact,
> friction, and high pressure rates. The homogeneous emulsion was fed
> to the engine fuel injector. ... Stabilized emulsions involve mixing
> of fuel and water with the addition of small quantities (typically
> 1-3% of the fuel) of chemicals which facilitate the formation of
> emulsion (emulsifiers) and prevent or delay separation once the
> emulsion is prepared (stabilizers). ... Emulsions must remain stable
> for a sufficient period of time to prevent separation in the fuel
> tank. In practical terms the required stability period must be at
> least several days, preferably several weeks."
>
> Companies like Lubrizol, Caterpillar, Aquazole, Clean Fuels
> Technology, A-55 et al probably have more stable solutions than that.
>
> Biodiesel brewers using used cooking oil as a feedstock find that the
> longer the oil has been cooked, and the higher the cooking
> temperatures, the higher the level of Free Fatty Acids will be, and,
> almost certainly, the higher the water content of the oil, which is
> of concern because water interferes with the biodiesel process and
> should be removed first.
>
> This is what one Biofuel mailing list member said about water removal:
>
> >Water in vegetable oil can exist as free water, which will
> >eventually settle to the bottom of a vessel; as suspended droplets,
> >which may settle if the oil is heated, or the droplets are
> >coalesced; and as water in solution with other impurities in the
> >oil. Free water is the easiest to remove. The droplets are removed
> >most efficiently by coalescing and draining. Suspended droplets that
> >cannot be coalesced and water in solution are more problematic.
> >
> >Boiling off the water is more difficult than it appears on the
> >surface. Colligative properties of solutions (and some mixtures) can
> >make removal of the last traces of water almost impossible. Water
> >mixed with oil will not boil at the same temperature and pressure as
> >pure water. As water is removed, more heat or lower pressure will be
> >required to remove more water. If the oil contains salts or
> >semi-soluble fatty acids, distillation is even more difficult.
> >
> >As the percentage of water in the solution decreases (its molar
> >fraction) its vapor pressure will continue to drop. Lowering
> >pressure in the system alone may be insufficient to sustain
> >vaporization when the solution becomes concentrated (the molar
> >fraction of the solute greatly exceeds that of the solvent). Results
> >will vary depending upon the nature of the water-soluble impurities
> >in the oil. Few solutions are ideal, in terms of Raoult's law, and
> >in used vegetable oil, there is no way to know what solutes are in
> >the oil.
>
> Sorry, that's not exactly a how-to, is it? Hope it helps though.
>
> Best wishes
>
> Keith Addison
> Journey to Forever
> KYOTO Pref., Japan
> http://journeytoforever.org/
>
>
>
>
> >Yours
> >A.D.Karve
> >
> >----- Original Message -----
> >From: Peter Verhaart <pverhaart at iprimus.com.au>
> >To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>
> >Sent: Monday, April 30, 2007 4:08 PM
> >Subject: Re: [Stoves] The PROTOS Plant Oil Cooker
> >
> >
> > > I still believe all vegetable oils will decompose thermally, into
carbon
> > > and vapours, making them unsuitable for pressurised burners such as
> > > Primus. The temperature would be in excess of 200 C.
> > > It would be nice if these oils could be emulsified with a tiny amount
of
> > > water. The steam resulting from heating the emulsion in the burner
could
> > > form a spray of small droplets that burn completely. In this way the
> > > oils would not be exposed to temperatures causing decomposition inside
> > > the burner.
> > >
> > > Peter Verhaart
>
>
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