Esbit burner testing

[Roger Caffin]

Hi Robert

The research effort needed to develop an alternative solid fuel ought to be miniscule in comparison.
Unfortunately, that ignores basic chemistry. The C-C transition to C-O2 is the highest energy source in the hydrocarbon/biofuel space, and it generates CO2. Granted, our needs are not great, but going to more complex hydrocarbons is just not going to do much.

Now, there are other bonds, like C-N, but they have their own problems, including the release of cyanide vapour. Those which are not toxic can sometimes be explosive, like NI3 (nitrogen tri-iodide). Do you want a bunch of juvenile males running around with cheap explosives? I got up to quite enough ‘fun’ with NI3 and so on when I was a kid.

Moving away from the carbon atom, we can have metals -> oxides. The trouble there is that they tend to release a little too much concentrated energy: have you ever used thermite? Too many of those reactions are either very expensive to set up, or subject to thermal run-away.

So while it is easy to say ‘there has to be something better’, like Comey on the subject of encryption, just wishing does not make it so. As for what do migrant refugees use for fuel?, the answer is very simple: wood.

Cheers

[rmeurant]

Roger, am I to be forced to apply an adaptive neuro-fuzzy inference system merely to advance thinking in this area? So much negativity! (I mean from various contributors). This is symptomatic of what I think of as the inertia surrounding Esbit alternatives/development/evolution – how about some lateral thinking? How about the “can-do” attitude? We owe it to Eric…

[Roger Caffin]

Basic physics and chemistry might be a better starting point. You can get so much energy out of carbon and hydrogen atoms, regardless of the initial molecular configuration, and that is it.

Non-hydrocarbon fuels might get you more energy, but there are hazards like explosions, thermal run-away and toxicity. That’s physical reality; sorry about Eric.

Cheers

[rmeurant]

That is interesting, because in my universe, form reflected in configuration is really all that is, rather than individual materials having any kind of unique physical existence. Substances only vary because their configuration varies; even various molecules are simply different configurations of the same fundamental particles – which themselves are more like mathematical states than matter. Naturally I respect your knowledge and experience Roger, but are you completely sure about this?

[Roger Caffin]

are you completely sure about this?
Sure enough.

even various molecules are simply different configurations of the same fundamental particles
Exactly. So one can do the maths and work out the energy yield from an arbitrary (typically hydrocarbon) molecule. Add up the oxidation energy yields from all the atoms and subtract the energy of the bonds you have to break.

Refinement: subtract the energy of vaporisation and the energy to heat up the ‘inert’ nitrogen in the air. It turns out that the transition from pure oxygen to air involves a significant drop in flame temperature – that can be many hundreds of degrees. But carrying LOX is a non-starter for UL.

Non-hydrocarbon fuels are just the same in principle, but the dynamics can be more complex. NSFJ (juveniles).

Cheers

[rmeurant]

Thanks Roger. This is clearly a case for Dr Who. We now suspect what powers that sonic screwdriver…

[Stormin]

The British Army are dumping hexamine in favour of Bio-fuel solid fuel.

https://www.firedragonfuel.com

Although the testing parameters seem very unscientific, the principle is the same. Double the weight for similar hexamine performance.

[Roger Caffin]

And the web site makes some false claims:
That Fire Dragon is soot-free while butane is not. My trust falls.
That butane is not air transportable: it is when in DoT-approved packaging (which is how canisters get shipped around the world). My trust fails. (Yes, I have had air shipments of propane/butane sent to me.)

Actually, the stuff looks just like domestic BBQ fire starters.

Cheers

[Ben H.]

Robert, trillions of dollars have been spent on research trying to beat the fuel density of hydrocarbons.  The military has a big research budget, but they certainly don’t spend it (or much of it) on the cooking habits of soldiers in foxholes.  You say refugees need something better, but unfortunately they are perhaps the least politically powerful people throughout history.   But… luckily for you transportation is in desperate need of an alternative to the standard hydrocarbon and they are pumping trillions into research.  So far that amount of money hasn’t done what you think could happen for pennies on the dollar.  Your clean burning, solid, reusable!, smoke and ash free fuel of the future is a battery pack.  The world IS working on it… they just are not there yet.

[Eric Blumensaadt]

Geeze oh man (quoting Radar O’Riley) guys. I totally forgot about de-tuned rocket fuel combustion gasses.

What the he!!, “toxic-schmoxic”, just burn it and stand back.

No in-tent cooking, no standing down wind, no  trying to get a high on it. BURNER BEWARE! That’s my take. Use it “sensibly” and let your mates discover the cancer-inducing side effects for themselves..

Meantime you have a HOTT fire. “Titanium cookware required”

BTW, SERIOUSLY? “Fire Dragon”?

[Eric Blumensaadt]

MAYBE ESBIT needs a more advanced combustion system.

I say “system” B/C I am inspired by the gassifier wood burners such as the Canadian Bush Buddy and the American Inferno insert into titanium Caldera Cones by Trail Designs. These systems re-circulate unburned gasses and they are then burned the 2nd time around, so to speak. And these stoves are considerably hotter than non-gasifier stoves.

Could we attempt such a re-circulation of ESBIT off-gasses to get hotter combustion? Have we ever explored this route? 

[Roger Caffin]

Hi Eric

It might work, but then you have to weigh up combustion efficiency gains versus extra weight to be carried, plus extra hassle in getting going.

Cheers

[rmeurant]

Eric, I suspect my custom 2L beer can rig does something similar, at least in the sense it prewarms the air before it reaches the flame (as a consequence of the lack of ventilation holes), which likely accounts for its good performance..

Ben, yes as I pointed out, there is huge research effort being expended on electrodes, batteries, energy harvesting devices, and what might be a more likely replacement for Esbit, fuel cells – many of the papers I edit are on these technologies, and have been for years, so I see upfront some of this research, before it is published (though I’ve not come across research explicitly on portable fuel cells). But I very much doubt that the present Esbit formulation is state-of-the-art solid fuel technology, (subject that is to Roger’s physical/chemical limitation/qualification), given that (as far as I am aware) the formulation has not been updated in recent time (unless perhaps with the change in packaging some years back), taken together with the intensity of (diverse) chemical research. Also, there is significant research on biofuel ongoing, especially for developing countries, though I encounter less of that, and what I have seen AFAICR has not addressed solid fuel.

I note the FireDragon fuel is also available as an “eco-friendly” gel, which is described as non-toxic, non-drip and made from 100 % natural ingredients, including ethanol sourced from UK grown grain stocks. The blurb claims it is easy to light, burns cleanly and their research shows that it boils quicker than meths. FWIIW. No doubt it (the solid version) will become available as chewing gum.

[Jon Fong / Flat Cat Gear]

Eric,

Could we attempt such a re-circulation of ESBIT off-gasses to get hotter combustion? Have we ever explored this route?

The Focus Fire 14 stove does kind of do that.  The Esbit is only partially burned at the inlet ports and the hot gasses (unburnt) rise the the top of the stove.  It is re-lit and burns at the outlet port.  My 2 cents

[rmeurant]

Following my earlier report of my visit to Dan’s laboratory, I was privileged to be invited to make a further visit with a BBC America reporter and a certain doctor of my acquaintance who shall remain nameless to the Zelph Advanced Post-Esbit R&D Facility, and was permitted to release a few photographs of the interior:

All in all, quite fancy plumbing. I understand he is working on a project to deliver his vastly improved version of Esbit in the field, where and more particularly when required – a sort of “just-in-time” supply process:

I wish him well with his activities, and look forward to his speedy return to this thread.

[Roger Caffin]

I am tempted to cry ‘Thread Drift’, but what would I know?

Cheers

[Eric Blumensaadt]

GAWD Robert! You are a d@mn genius and just SO fortunate to have such connections. With access to knowledge like that you will be an IPO billionaire in no time. Well, OK millionaire.

Give me a heads up when stock when that initial offering is about to be made. I want GROUND FLOOR timing!

[rmeurant]

Returning to Eric’s “Could we attempt such a re-circulation of ESBIT off-gasses to get hotter combustion?” question and Jon’s response, and in specific relation to my custom 2L ASAHI beer can derived windscreen (earlier discussed and with photos; quite some pages ago):
My screen consists of the lower part of the can, has a domed bottom, angled transition from base to sidewall, and its inner diameter is such that an open Esbit tripod just fits in nicely, and the legs just rest on the bottom, with the rivet and tray just clearing and virtually resting on the dome.
I generally use either a half or full 4g tab, depending on conditions, with Evernew 400 Ti pot, with lid, and typically between 250 and 310 ml of premade coffee (not that thick). In my opinion, this works well because:
1. The windscreen and bottom are continuous (one-piece). Hence cool wind does not enter thru any space between cylindrical windscreen bottom and ground (e.g. when resting on rough ground, pebbles, vegetation). (This is a critique of the Evernew Ti windscreen, though certainly not a deal-breaker).
2. Apart from the front opening to allow the pot handle and sometimes lighting, there are NO openings in the sidewall (or the bottom). I suspect this is the major factor in this system’s effectiveness. Hence cool wind does not penetrate through the sidewall of the screen (only through the front opening).
3. The domed bottom and Esbit tripod raise the tray from ground level so that there is in effect an insulating air pocket under the dome.
4. The interior of the windscreen is reflective (though not highly so), so that some radiant heat from the flame and warming pot is reflected back into the system.
5. Most of the air flow into the flame area is through the vertical space between pot and windscreen (other than the relatively small part through the front opening).
6. This air gets preheated from the warming pot and the hot windscreen, so that by the time it reaches the flame area, it is hot.

This configuration allows the system to be used in very gusty conditions; the only problem then is initial lighting (normally I just use an ordinary Bic-type lighter), which is a pain. I hate Bic-type lighters. Once the tab is alight, I can forget about it, it is not going to go out, though I like to stir the coffee regularly.

An incidental advantage I’ve discovered is that the closed windscreen and tapered base mean it can be placed easily on uneven ground and vegetation, worked into pliant vegetation, and has proved safe in use (not setting fire to surrounding/underneath vegetation). For storage, the 400 pot sits nicely inside (having taken the tripod out), and the pot with lid readily contains all the accessories, including folding Swedish cup, fuel, spoon, tripod etc. The whole screen + pot + gear is then enclosed in plastic bag and (more recently) tidy Evernew “Ti 570 cup” zip-top neoprene case. Other than the conductive heat (too hot to touch), I even suspect I could brew up (in cold conditions) cradling the system in my lap – maybe nestled inside an old jacket (QED; I have that much confidence in it). Or maybe the heat from the top and maybe the fumes would be too much; and if I sneeze… (Don’t try this at home – or elsewhere).

The main disadvantage is that larger pots or frying pan can’t be used with the system, which was one of the reasons I moved to the Evernew Ti windscreen, Titrivet, tray, base disk system earlier mentioned; but I’m still exploring options.

The main improvements possible would be an insulating layer on the outside of the windscreen; custom detachable Ti wire hanging tensile tripod (I’ve used a proprietary enclosing hanging system occasionally); somehow flatten and depress the top of the base dome to provide an Esbit tray so the Esbit tripod is not needed and support the pot probably on wire network or Ti pegs penetrating the windscreen; and beefing up the reflectivity of the inner surface of the windscreen, so more heat is reflected back to the pot and flame.

[rmeurant]

P.S. The hanging version makes a great deal of sense for use in a tent, using ample caution. Just getting it off the ground helps tent life.
P.P.S. Not having ventilation holes in the sidewall also makes the idea of an outer insulating shell more feasible, it would be something like neoprene (?) glued to the outside of the windscreen. This means the whole system could maybe be held while heating, and using just one hand, placed down wherever, provided the heat can still escape from the top and the liquid ain’t going to spill. It becomes conceptually a (quite radically) different stove system. In principle.

[Eric Blumensaadt]

Robert,

In your above description I understand that most of the combustion air will enter by the one opening in the wind screen. And as you said, this air is partially heated by passing the warm pot sides. However I’m talking about re-circulating the gasses given off by the burning ESBIT.

Perhaps a vented sleeve around the BGET tab holder (similar to the Inferno sleeve in the Sidewinder and Tri Ti stoves) so that air is drawn into this sleeve to help combust any unburned gasses. If it works for wood then why not ESBIT? I’m no specialist in thermal properties but adding more air, and likely speeding up air speed thru the sleeve vents via convection, would seem to be a worthy experiment.

A study of the design of the Inferno insert would be in order methinks.

ESBIT GASSIFIER SLEEVE CONSIDERATIONS:

1.size

2. height

3.number of vent holes

4. size and placement of vent holes

So I’m tossing this out there for experimenters like you and Dan to play with. (But remember, notify me just before making the IPO on this “hot” product.;o)

[Ken Thompson]

“I am tempted to cry ‘Thread Drift’, but what would I know?”

Great, you’re a moderator.  Rule #4 states

”Moderators shall delete or move off-topic posts from threads, move off-topic threads to the appropriate forums, edit or delete posts that violate forum guidelines, close threads that are subject to repeated incidences of violating posts and communicating with users who do not adhere to forum guidelines. Neither moderators nor admins will be expected to communicate to users who have a habit of posting content that violates forum guidelines, including trolls, spammers, or members who repeatedly violate forum guidelines.”

9 is a good read too,”

1. Moderators shall agree to the vision, policies, and guidelines of forum moderation as outlined in this document, as well as abiding by the Terms and Conditions of Backpackinglight.com website.

I certainly am not a fan of all the copy and pasting without due credit given to where the copyrighted material came from.

But I’m sure Roger will just continue to be Roger.

Cheers.

[Roger Caffin]

Yup

[rmeurant]

Eric,
I think schematics are in order. I’m a little busy, so will have to delay a cross-section and 3D model of my beer can rig, showing what I imagine to be the air flow, but I’d like to understand what is going on in these various stove/pot/windscreen configurations. I take your point about recirculation, but what drives it? That might seem like a silly question, but in reviewing my rig, I just presumed that air is drawn in the sides, heated en route, and I suppose expelled through the front opening – it would have to go somewhere. But why should it thus circulate, or even, does it in fact? I assumed the air in the front region is not as hot as the air near the sleeve; but is that sufficient to cause air circulation; or is there simply molecular transfer of oxygen from the normal exterior air to the depleted air in and about the flame? And maybe radiant heat from the flame means that the air near the front opening is in fact hotter, not cooler, than the air near the circumferential sleeve, which only has the benefit of radiant heat from the walls of pot and windscreen (and superficial conductive heat).
The paper I mentioned on bioliquid versus heavy fuel oil in large-scale power plants observes the flame inside the boiler (providing photographic images), describes it at various stages of burning, and measures various parameters, such as the temperature at various points, and the fuel and air flow rates, then analyzes the relative performance. (Unfortunately I cannot cite it, as it is still under preparation, confidential, (I presume) not yet accepted for publication, and in any event blinded to me as editor (author names not shown)).
A different consideration is the robustness of the (Esbit) burning in the presence of highly fluctuating air pressure and air velocity, i.e. in blustery conditions.
A third consideration is the possibility of controlling the flame presumably by throttling the air flow to accommodate various environmental conditions (ambient temperature, wind conditions), the quantity and density of the payload (liquid/stew), and the desired temperature of the drink/food and duration of cooking. Another control option might be to have an adjustable distance between fuel and pot (which ideally could be adjusted during use).
In the process of all these various explorations, maybe we can evince or further refine principles to the definitive deterministic design of effective everyday Esbit exploiters that could inform the design, manufacture and use of future highly-efficient integrated stove/windscreen/pot/fuel systems.

[Roger Caffin]

For copyright and trademark purposes, please note that it is ESBIT, not Esbit or esbit. I quote the company:
Esbit means „Erich Schumm Brennstoff in Tablettenform“ (Erich Schumm fuel in tablet form).

Even though so many vendors ignore this. Like Aspirin.

Cheers

[Eric Blumensaadt]

OK Robert, Roger, et al, ESBIT it is and may it always be so.

SO MORE ON THE GREAT ESBIT GASSIFIER SLEEVE:

On thinking about a gassifier “sleeve” for surrounding the BEGT tab holder it may be that the sleeve needs to be double walled with the outer wall solid and only the inner wall ventilated. But air needs to enter between the walls from the bottom. In any evert I’m after re-circulation of gasses & air. So the sleeve needs legs, preferably 3 of them for stability on uneven surfaces, like a milking stool.

I now have much greater respect for the Trail Designers taking on their task of designing a an insertable and collapsable gassifier sleeve in the ti Caldera Cone. Obviously they knew titanium was needed for the increased heat of this type stove. The Canadian Bush Buddy of course has a double wall and it is made of stainless steel to withstand the heat.

I doubt ESBIT will generate that much more heat from a gassifier sleeve, if indeed we can get it to make any heat increase at all. Like the BEGT tab holder giving us the ability to burn the liquid residue for a longer burn time I’m hoping a gassifier sleeve will add to ESBIT’s efficiency with increased heat.

Hey, at least this gives us an idea to study. I guess the sleeve should be aluminum, at least for experimentation – but perhaps not beer can thin. Maybe aluminum beer bottle this for the outer sleeve. And tomato paste steel can for the inner??

Gyro Gearlose now retreats to his workshop, the Invent Help number on speed dial.

 

 

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