Sciencemadness Discussion Board

running a piston-engine from ethanole-water-vapor

chief3 - 18-1-2015 at 00:41

The idea of bio-fuel is inspiring me these days ... ; there surely exist cheap ways of producing ethanole from fermentation ... ,
==> the only problem ist the putification of the fuel, i.e. removing the water ... ... .

Now the average piston-engine (alias otto-motor) produces great amounts of heat ... ;
==> that heat could be used for distillation ... .... , right ?

Also the 65% alcohol, achievable after the first step of simple distilliation, are burnable, although maybe not too ignitable ... ... ; in motorsports there are even projects for water-injection (besides fuel) ... to _cool_ the engine ... ... , so water-vapor does not have to be harmful for the engine ...


The idea now would be ... to run a somewhat scaled-up fermentation, of maybe 2000 liters, which will reach a ethanole-content of maybe 10 % within a few days ... .

Then one would constantly filter out some of the liquid , and distill the ethanole out of it with the exhaust-heat of the piston-engine ... :
==> The resulting ethanole-water vapor would drive the engine (generating electricity or whatever), and the undistilled liquid residual would be fed back into the fermentation-vessel ... ...

Some of the cornerpoints of the idea are:
==> Most of the fermentation-liquid would never get overheated, since the 2000-liter vessel means a high thermic ballast ... , so the fermentation would go on continuously ... ; new nutrition for the yast (potatoes, sugar, whatever) would be added continuously ...
==> The 2000 liters of the fermentation could, at 10% ethanole, contain 200 liters of total ethanole ... , re-generating each few days ; this could run an engine of some kiloWatts continuously, even a car-engine ... , producing electricity or mechanical power ...

This also could be legal in most countrys, even when there is a prohibition towards distilling, ... since there never is obtained any concentrated ethanole ... , at least not beyond the vapor ... which gets combusted immediately ... ... :D

What do you think about it ?

A good distilling-unit would be required ; then the engine would distill its own fuel ... :o , and the otherwise difficult to re-use exhaust-heat would serve a purpose ... , which could make the energetic efficiency of such a setup better than many others ...

Also a potential problem: The fermented liquid with the 10 % of alcohol will be saturated with CO2 ... ... ; maybe its a problem, maybe not ...


Has anyohe tried to simply ignite the vapor out of the still ? Does it burn well enough to drive an engine ?

[Edited on 18-1-2015 by chief3]

[Edited on 18-1-2015 by chief3]

Zombie - 18-1-2015 at 13:48

It won't work that way... What you are proposing is a perpetual motion machine.

I distill.

Fermenting requires around 80* f and approx 10 days to achieve. Less if Turbo yeast (AKA Fuel yeast) is used.
A simple one run pot still yields about 60% abv Eth. (ETOH). Two passes will get azeotrope or 96%abv. This will run any IC engine. No need to remove any more water because as you posted water will convert to steam, and raise compression ratios, as well as reduce combustion temps.

A fractional still will produce fuel (AKA 192proof Vodka) in one run. You can get anywhere from 1-12% return on your mash/wash volume in fuel.

I would suggest you look into "Home Distilling" forums for more insights as to the methods, and equipment.
There is one based here in the US that is a fountain of knowledge but they tend to beat up on new comers. There are two based in Australia that are more user friendly. One belongs to a fella that sells his equipment on site so the scope of the forum is pretty narrow, and the other is a site full of experienced distillers that welcomes all. (guess which I am a member of?)

Distilling your own fuel is a great goal. Problem is the people that sell ready made fuel will put you in prison for treading on their ground.
Same can be said for the people that bring you drinkable fuel. The profits, and taxes brought in from both of these groups are too high to allow word to spread that WE DON"T NEED THEM!

Check out those forums or PM me, and I'll help you get started. (IDK if posting other forums is allowed here)

Good luck, and break the big oil habit!

Quick edit...
The simple act of distilling ANYTHING that produces alcohol is illegal in MOST countries.
In many US states it is a felony to own any sort of "still" over 1.5 gallons, and many more states it is a felony to own one of these tiny stills, and have any sugar/yeast on the same premises.
It's akin to the analogue act pertaining to precursor chemicals.

Hell, where I live just looking at a still on the ":net", and having a mason jar in the pantry is an issue:D

Big oil, and Jim Beam have our govt. by the balls, and guess who feels the pain...

[Edited on 18-1-2015 by Zombie]

Zyklon-A - 18-1-2015 at 14:24

Quote: Originally posted by Zombie  
It won't work that way... What you are proposing is a perpetual motion machine.

No it isn't.
The energy starts in the sucrose (or whatever he's fermenting).
Sucrose is continually added and that's where the energy comes from, not the fermentation, which only transfers the energy from a solid with a high molar mass to liquid with a much lower one.
A perpetual motion machine with this design would be more like burning alcohol and using the energy released to both move the car and somehow make more alcohol, or at least make more alcohol.

[Edited on 18-1-2015 by Zyklon-A]

Zombie - 18-1-2015 at 14:49

No need to take it literally. There are fundamental flaws in the approach.
Yes you can fire a boiler under the heat from an engines exhaust but depending on how efficiently you harness that energy, vacuum assist may be needed.
Secondly you can make/run a continuous stripping column to "strip"ETOH from a wash but you can not make a continuous "EFFICIENT ferment.
It doesn't work that way.
Partial ferment is not effiecent.

It's like most things... Using a fuel source to create fuel... think about it.

I have.

I have a fuel column that uses solar heated water to fire the boiler. (ie:free energy)
It is not enough energy to heat the boiler to temp so a vacuum assist is needed to lower the boiling point. The transfer of energy from hot to cold supplies the vacuum (ie: free energy)

This is why I pointed towards some distillation forums. A basic grasp of the mechanics involved can/will lead to "light bulb" moments where a free thinker can/will develop methods, and ideas that can change the way things are done, as is Chief3's intent.

It took me 1 year of 10-12 hour days, and thousands of formulations to come up with what I have.
It can not be explained here in one post so I used PM machines as a blunt instrument. Not a literal example.

No offense.

Mesa - 18-1-2015 at 15:09

My dad worked in a sugar mill in Fiji prior to immigrating here. I remember hearing how they used the processed cane mulch to fuel the boilers in a continuous cycle. You'd think a process like that wouldn't be nearly efficient enough to be self-sufficient, but supposedly they still had a decent excess of mulch needing disposal.

That being said, they did use huge diesel powered vacuum pumps in the process. Also, living organisms(such as yeast) are always going to be the bottleneck in the system as far as energy efficiency goes.

As an aside, I thought the popular projects in the biofuel area were trending towards producing Butanol from cellulose rather than Ethanol. How difficult would the Butanol process be to enact on a non-commercial scale?

phlogiston - 18-1-2015 at 15:14

This claims "280 MMBTU/hr energy [are] consumed to produce 100 MGPY ethanol"

I like the metric system, so I convert:
So 280 MBTU/hr = 280*1E6*1055 = <b>295.4 GJ/hr</b> to produce 100*1E6*3.785 = <b>378500000 liter per year.</b>

So, to distill 1 liter of ethanol fuel requires 295.4 *1E9 * 24 *365 / 378500000 = <b>6.83 MJ of energy.</b>

The heat of combustion of 1 liter of ethanol is 789/46.07 * 1300 kJ= 22.26 MJ
A typical efficiency for an internal combustion engine is 20%, so 80% of that is available as heat, or <b>17.8 MJ</b>

So, if the source of these numbers are at least somewhat in the ballpark and I didn't make any errors, at least it seems the engine is indeed likely produce enough heat to make distillation of its own fuel possible.

Zombie - 18-1-2015 at 15:45

They are reading combustion temps.
Unless you can fire a boiler from inside the combustion chamber... it's out of the question. Again=, back to efficiency.

Yes you can fire boilers of of the flac left from sugar processing. But as you said... Vacuum assist is needed for this to self sustain.
What powers the vacuum? Well you could use an ETOH powered IC engine. I doubt there would be enough to make it self sustain.

Engineers have been down this road for several centuries with ETOH.

What you have to do is apply the laws of natural science, and the doors will open. Free energy is supplied by physics, and our environment (beyond my scope) but the simple things like solar power, and thermal energy are not.

Step back, and see the trees. Forget the forest.

Design an efficient fuel column that uses the heat it produces to rectify (clean) it's product, and then figure out how to get the energy to power it. There in lies the key to sustainable energy.

Find the FREE energy, apply it, and it's done. No debate.

Here's an interesting fact.
Ethanol vapor contains 1.5 times as much energy as it took to create it. Meaning once you create that vapor it has enough energy stored to reproduce itself, and have an excess of energy. Sounds like a PM machine huh.

That's how a "thumper" in a pot still works. The vapor carried from the boiler will boil a new boiler. You can continue this in a chain until thermal losses to the environment cause it to fail.

Thermal losses equal free energy if you can grab it.

[Edited on 18-1-2015 by Zombie]

chief3 - 18-1-2015 at 20:56

Tanks to @phlogiston: You perfectly understand what I mean ... :D
==> A halfway good still might/should work to produce enough of the ethanole ... .

Question is: How simple can it be and still run ? Would the 60% Ethanole-vapor ignite in the engine ?

To @Zombie and the others: The fermentation can be run continuously ... if the "batch" is large enough ... ; thats why I was talking about _2000_ liters (3 zeros there ... ) ; if from such a large batch continuously maybe 200 liters per day are filtered for distilling ... then 1800 liters remain untouched ; also by the filtering the yast will be removed and remains in the vessel ... , so the fermentation should go on undisturbed ... as long as the batch doesn't overheat ... ; if it does it could be scaled up ... .

Now also a word to the legal considerations: Probably, as I understand it, the act of distilling by definition is the act of obtaining _liquid_ alcohol ... ; but the idea only aims for vapor ... which directly goes combusted ... :cool: ; also at no moment there is any more than a minimal amount of such vapor ... ... ; so it should be legal under most circumstances ...

Anyhow: If other fermentations may work better than that of alcohol (and are feasible) ... I'm in on those ... ; fermenting starch to butanole would make cheaper raw-ingredients usable ... ...

[Edited on 19-1-2015 by chief3]

Zombie - 18-1-2015 at 22:04

60& will burn but it will not ignite as a vapor. The highest water percentage you can run as a vapor mixed w/ any fuel is 25%, and that is in very specialized , high compression engines.

The constant ferment is also still flawed. The raw sugar will mix, and 100% fermentation is never achieved. Therefore you might as well throw that sugar out. It negates the point of fermenting.

I ferment well over 2000 liters, and I assure you that is Nothing compared to commercial level, and they do not/can not continuous ferment.

The solution is Staged ferments. whatever quantity started at 2-3 day intervals, and constantly cycled.
The yeast can be transferred from ferment to ferment so that is not an issue.

Now... Lets say "THEY" made water illegal. They came to your house, and you had no water. They open the freezer, and low, and behold... ICE!!!
Are you really going to argue that it technically is NOT water but rather something else?

Anything that produces DISTILLED ETOH in the US is illegal. I don't care if you boil beer (that is distilling). If you collect those vapors... You are now Bubba's new girl friend for at least 5 years

You can ferment almost anything. I think a dead cat will make some ETOH but sugar is the easiest, and cheapest in terms of volume / return ratio.

Keep thinking, and most of all keep researching on distilling. There is a whole lot more to it than lighting a fire under a pot with a hose on it. At the same time it is as simple as that.

This PDF will highlight some of the principles involved. If you truly want to design an efficient column/distillation plant, the first tool you will need is Matlabs software. Unless you just copy someone else s work... but that just s@cks.

franklyn - 19-1-2015 at 13:04

This is just the sort of armchair project to tie your brain in knots. As phlogiston points out, this all depends on heat flow and thermal output. Start with this premise, how much of the distillate would be needed to burn off in order to distill a given volume of ferment. How much excess unburned distillate remains. This product provides a baseline for assessing the economy. Distilling would need to occur in a flash boiler of the type used for steam engines, so perhaps that might capture some energy beforehand used to drive a steam engine with the distillate. The use of an internal combustion engine is just a fancy burner which can capture some energy to do work. Both types can be coupled in tandem to run together. The question is if enough latent heat is available from the water jacket, the engines heads, and exhaust to heat the ferment without a dedicated boiler to provide enough distillate as fuel. In such case the boiler driven steam engine is called a bottoming cycle engine, because it runs off the exhaust waste heat of the internal combustion engine. Simply boiling at no pressure to provide fuel to run the internal combustion engine if only intermittently at idle can be done, the question is can enough distillate be produced to run it at appreciable load continuously. The next question is what amount of source ferment would be needed. 2000 liters is very small, my gut tells me you'll need a pool size fermentation vat for that, something on par with commercial winery or breweries. For comparison, natural gas derived from buried decaying biomass requires acre sized plots.

The simple setup is, material is put into the fermentation vat which after a set time frame shall have undergone fermentation to a conclusion. This content is then emptied and moved into a storage tank to make way for another batch run in the fermentation vat. The storage tank provides the feedstock for distillation. Assuming a fluid not a mash, the feedstock is moved into the engine water jacket up to the heads and out to the boiler where combustion exhaust heats to boil off the vapor which is directed to the carburetor. The engine should be inside an enclosure drawing in fresh air for cooling which then passes around the boiler housing separately. Together with the exhaust from that blows on a pre-heater section fed from the storage tank, possibly by a forced air duct through a radiator circulating the ferment. The hot liquid waste runs thorough a heat exchanger stage of the pre-heater first then goes on to transfer heat to the fermentation vat by an immersion radiator. Channeling heat flow in this way is called cascading and provides the best efficiency.

Other arrangements incorporating an auxiliary burner for the boiler or even a steam power section adds ever greater complexity. This sort of engineering is only ever cost effective at industrial scale as seen in petrochemical works. Note that flammable by products in refining and petroleum drilling are routinely " flared " meaning they are just burned off since it is not remunerative to utilize such small amount.
( personally I disagree )

Distilled Spirits as detailed by the Bureau of Alcohol, Tabacco and Firearms, means consumable as drink. Industrial production not to be sold or trafficked goes by different guidance. Anyway enquire within.;sid=33fc0c0194b5...;sid=33fc0c0194b5...;sid=33fc0c0194b5...


Chemosynthesis - 19-1-2015 at 13:18

I think passively distilling alcohol via the waste heat for use as an anti-detonant may be more feasible.
I've seen alcohol injection kits for automobiles which routinely recommend a 50/50 water to alcohol (usually methanol, but ethanol can work), and MW 50 dates back to WWII.

deltaH - 20-1-2015 at 02:56

Why do you want to specifically do this by way of alcohol? If your goal is run your car on fermentable biomass, then you could build a biomass gasifier and not have to break any laws (bonus). Plenty of info on the net on DIY versions AFAIK. I'm sure car engines could be modified to burn the gas produced as it's primarily a mixture of CO and H2. You just need someone to keep shoveling plant material into the reactor. Would work nicely in something like a minivan and would be sure to grab some headlines!

PS. Make sure the reactor and gasifier is well ventilated, you don't want to gas yourself!

[Edited on 20-1-2015 by deltaH]

chief3 - 20-1-2015 at 04:39

Well , I reply the following:
==> 2000 liters may be small , but at 10% there surely will be 200 liters of ethanole in it , not ?

Of course there is somewhere a optimum for the fermentation-speed: A specific sugar-content, and not too high in the alcohol-percentages ... . The fermentation surely can be driven at parameters near the optimum ... , of course .

Also: The distillation uses the _excess_-heat of the engine ... , no other energy is used beforehand for the distillation ... ; if you would want to distill the ethanole beforehand ... it would be much more uneconomic ; it seems some of the posters refer to that ...


Of course the ethanole-thing may be illegal in the US - but I'm in Germany ... :D

Meanwhile: Ethanole is the easiest fermentation ; if it runs on that ... it may be developed towards something else ... ...

@Zombie: If bakers yast can ferment a dead cat ... what other usable fermentations do you know ? ?? Corn eg. costs 200 $ / ton ... ...


@Franklyn: You somehow gave me the idea of directly driving a steam-engine on direct fermentation-product ... :cool: ; how much ethanole has to be in the water to directly make it combustible somehow ? ??

If you have for experiment
==> a vessel of maybe 50 liters of 10% ethanlolic fermentation-product ...
==> and heat this into temperatures of 60-70 [Celsius] ...
===> Then you blow air through the liquid ... and achieve an ignitable vapor of air with more or less ethanole... ... ; some of the heat is used to sustain the temperature of the vessel ... ... , some of the vapor is combusted for any use ... ... ...

From the childhood I remember: Brandy of 35% alcohol was poured onto the hot stove - the vapors were ignitable ... ...

The said vessel maybe kept at temperature by just leading the exhaust-pipes fom the burnt gases through it ... ...

[Edited on 20-1-2015 by chief3]

Zombie - 26-1-2015 at 11:17

the 35% Brandy is not burning. It is the 95%ish vapor that is igniting.
I believe 95% is the lowest you can run in an IC engine. I have run weed whackers, and other 2 stroke engines much more efficiently than any 4 stroke engine.

Anything organic that contains either starch or sugar can be fermented. It makes no sense to use cats thou... Obviously they make too much of a fuss.

I have no mis conceptions as to what you are asking. I am simply trying to point out the walls you will hit, and the reason they are there.

I have developed a concentric mixed media fuel column that runs under vacuum on solar heated water.

The reasons for making a concentric column are many fold but the main goal was to capture, and use the heat energy created/lost inside the column to aid in distillation.
A simple "pot still" can not produce fuel grade etoh.

You have to start somewhere right?
What fires your boiler to begin production? Some sort of fuel?
You are already behind on the approach. Solar will work but a vacuum is needed for the temps to begin distillation.
Where did the vacuum come from? Behind again.

You always need a horse to pull the cart on level ground.

Lets go back... Heat from anything is not needed for fermenting. That is an exothermic reaction.
Heat is needed for distillation.

Continuous strippers, and rectifiers are already all over the place, and staggered ferments abound.
The key to your puzzle is getting the boiler fired. Heat soaking is one option where the engine fires to heat a mantle, and once soaked the engine stops. So does the vehicle, and you have to start again.

One aspect that might help you is the fact that Etoh Vapor contains enough heat energy to boil more Etoh from a liquid mixture. It carries 1.3 times the heat required within it self.

I'm trying to keep it simple, and I don't want to appear to be slamming your idea. Honestly there are much more efficient methods to create cheap energy.
Hydrogen cells / Bloom cells are both much better. Electro magnetic pulses running Hydro Dynamic engines are what is going to be.
ETOH production for IC engines is just a stop gap solution to a short lived issue for oil starved /third world nations.
The US has done their part to see to this.

I have no way of knowing what your end goal is...

Magpie - 26-1-2015 at 18:39

Wood-Gas-Vehicle-Front.jpg - 13kB
Wood burning truck in North Korea :D

Zombie - 26-1-2015 at 19:33

There you go. I believe these were mentioned here. Perhaps in another thread.
There are essentially self contained methane production plants, and they have been around since the early 1900's.

Wood is used to produce Methane/wood gas to run the IC engine. Easy process but not very safe or user friendly.

Here's a link that might lead you somewhere...

When I was a kid my grandfather had one on Long Island that we would tool around in. Not ideal but they produce almost ZERO emissions. I believe oil in the crank case causes the majority of carbon emissions.

[Edited on 27-1-2015 by Zombie]

Nicodem - 27-1-2015 at 10:35

I can't understand the topic of this thread. Why would you want to distil aqueous ethanol from fermentation broths just to then burn it in an engine, when it is more energetically economic to distil the azeotrope which in addition runs the engine with a much better efficiency? If this thread is about energetic efficiency, it is obviously based on a wrong assumption.

For example, to distil ethanol to a concentration of 90% consumes less energy than to distil the same amount of ethanol of a 50% concentration (assuming good insulation). Water has a higher enthalpy of vaporization than ethanol!

gregxy - 27-1-2015 at 11:10

A friend of mine says they are working on a small system for laundries that burns natural gas in an IC engine to produce the needed electricity then uses the waste heat to heat water and dry the clothes.

Zombie - 27-1-2015 at 11:39

Very easily done, and a worthy undertaking.

I have 300 feet of black 1/2 inch tubing on the roof to collect solar heated water. My gas fired hot water heater has now become a tempering tank to cool that water as it reaches 160*f in the summer here (Florida).

Point is... There are lots of ways to capture free, and waste energy.
An ethanol distillation column fired by an internal combustion engine is not the most efficient means of acquiring or creating energy. IC engines are about the least efficient fuel users made today, and Ethanol is as I said... a stop gap solution for an inefficient engines fuel needs.
Big Oil will have it no other way.

chief3 - 28-1-2015 at 03:01

@zombie: Of course the 35% brandy doesnt burn, but its the vapor ... .

What I believe that you didn't get is: The heat for distillation is to be the _excess-heat_ of the engine ... ... ! That excess-heat cannot be avoided, but usually will not be used ... but exhausted ...
==> The idea is to use this excess-heat, after the combustion-cycle, to distill more of the ethanole ... .

The exhaust of the engine usually will have 500 [Celsius], and its blown into the air ... ; those 500 [Celsius] can esily be used to heat some ethanol/water mixture to 78 degrees, don't you think ?

If I were to plainly distill 95% ethanole I would use coal for the purpose , which is several times cheaper than oil or something ... .

I'm talking in this thread about a possibly stationary piston-engine, that is eg. in the cellar or a special outdoor-bunker, with the purpose to produce eg. electricity ...
==> Electricity may be cheap in america, but is very expensive in some other countries like germany ...

In another chamber of the cellar there would be the fermentation-setup ... ...


But I'm now also very interested in fermenting butanole or other fuels from corn, wheat, starch or anything the like ... ; seems I will have to open another thread for this, so things get not cluttered here ...

The new thread can be found here:

[Edited on 28-1-2015 by chief3]

Zombie - 28-1-2015 at 11:47

Now your getting thru to me... Yes you could run a fuel ETOH column of of the exhaust gas heat of an IC engine, and Yes that engine could be used to run an electrical generator.

You would have to do the math to see if you could strip/rectify enough ETOH to keep the system self sustaining. That will be determined by the size of the column, and in turn the production rate of that size column.

You would NOT use a boiler but rather an injection system of pre heated mash, and a concentric column will re-cycle the heat of the stripper into the rectifier.

Now you simply need to apply the math to determine the needed hardware, and the expected efficiency.

If you like I can lead you to some column design info, and web sites that contain the calculators you will need.

For the entire length of this post I was believing you wanted to drive a fuel column around in a fermenting Pinto full of cats. Now I understand...

chief3 - 29-1-2015 at 01:14

I'm glad we understand each other now .

==> Yes, I'm interested in the design of such distillation-columns ..., please give some links if you can ... .
==> Also: What about directly fermenting starch ... (in the other thread) ... ?


Also, now that some things are clear:
==> What purity must the ethanole-vapors have to run the piston-engine , i.e. to ignite reliably ?

Zombie - 29-1-2015 at 10:43

This first link will cover all the basics of column types, and internal structures. You will need a column type still to reach azetrope in one run thru.

This one hits the basics in operation.

This site has LOADS of home built fractional columns...

My guess would be if you run a continuous stripper/rectifier in the 3-4" range you could produce 1 - 1.5 gph of 95% ETOH. That would mean
10 - 12 gph of mash would need to be produced.

A single column of 4" x 8 feet tall containing 2 sieve plates (stripping section), and 5 or so feet of stainless packing (rectification section) I think could produce your ETOH with very little reflux required.

For the starch... I'll look at the other thread but mainly it is just an enzyme, and temperature conversion to ferment-able sugar.

[Edited on 29-1-2015 by Zombie]

[Edited on 29-1-2015 by Zombie]