Almost afraid to ask about hydrogen formation

General Discussion
#1

Yesterday I got beaten about the ears over on the gasification list for asking for ways to maximize hydrogen generation in a wood gasifier.
One guy told me that hydrogen and oxygen in a balloon would blow up if ignited, and so (I guess)----- I shouldn’t ask any more dumb questions unless, I suppose I had a PHD in something related.
Surprise! I already knew that.
And no, I am not a Brown’s Gas guy, trying to get rich making hydrogen under the hood of my car. I just want to understand a little more about role that wood moisture content and incoming air moisture play in the reactor.

Here’s the body of the post I made:

I probably have no business asking entering into this discussion since I am neither a chemist nor a physicist, but—
Over the last several months I have been trying to learn the “truth” about the dissociation of the water in my wood chips into Hydrogen and oxygen. I had previously read someplace that it was a pretty simple process. You just heat water to somewhere above 350 degrees C and there you go.
Well, lately I have become quite disconcerted as I have read that there are so many other factors that can be involved, that it’s anybody’s guess as to whether it will happen at all.
Some of the variables:
Pressure
Temperature (obviously)
Residence time
Presence or absence of carbon and form of that carbon. And, apparently, the availability of carbon from other molecules.
And apparently, the list goes on and on.

So what is an ordinary human with a stratified downdraft gasifier to do to reliably pry enough hydrogen out of the process to make it worth doing?

I guess that I HAD thought that a little moisture was a good thing, since IF we get some hydrogen and some O2 to use to enrichen CO production,
we’d get a higher energy gas. But from what I have been reading. the dissociation doesn’t occur to any substantial degree at temperatures below 2000 C.
(one scholarly paper said " about 1 1/2% of the water molecules will have separated at this temperature")
I know my own gasifier doesnt’ get that hot anywhere, but I don’t think I have ever heard of even a good Imbert design getting that hot.
I do know from my vacuum heat treating backgroung that even Inconel won’t survive at that temp. We considered that Inconel was good in a high vacuum only to about 2150 defrees F.

See why I am confused?

I also commented on the easy and cheap availability of gas sensors to use with and Arduino (automotive guys, cover your ears) and was beat up (politely, but beat up, none the less) for not my comments.
Have any of YOU measured hydreogen?

Pete Stanaitis

#2

Hi Pete,

We won’t beat you up here. :slight_smile: It’s really quite simple once you understand it, and one of the awe inspiring parts of gasification.

Hydrogen formation happens in the reduction zone. Water vapor (steam) is headed down through the glowing charcoal bed. The carbon is hungry for one thing, and that’s oxygen. It will strip the oxygen molecule off of the water, creating hydrogen. This process takes energy, and so the reduction zone is endothermic (requires heat). The carbon and oxygen molecules form CO.

Same thing happens to the carbon dioxide. The hot char strips off one oxygen molecule leaving CO, and forms a second CO.

The awe inspiring part? Combustion is the exact opposite of this process. CO combines with O to create heat and CO2. H2 combines with O to create heat and H2O (water vapor). Now you have the raw ingredients for making more fuel - add them back to the charcoal bed and you can keep the reaction going. This is one method of stabilizing a charcoal gasifier by using the engine exhaust.

Here’s Wayne’s gas analysis taken at Auburn University in AL. He’s got about 22% hydrogen content, 22% CO, and some inert gases.

Appendix%20B%20-%20Final%20Report_Page_07_Image_0002.jpg974×731 102 KB

#3

About the moisture - there’s already excess water in the wood to make hydrogen. Some steam will get through as well. No need to add any water. Kiln dry wood might make a little less hydrogen, I don’t know. Charcoal alone makes almost none, so they sometimes add water to charcoal gasifiers to facilitate hydrogen production.

If you want to increase hydrogen production the best way is to have a deeper char bed. There will be more charcoal to react with, and less will get past the hearth as steam.

#4

hi, Pete
I understand completly. You might try talking about grass clippings as fuel-- same responce.

Yes, you can put superheated low pressure steam into a fully heated simple fire and get pure syn gas.
Twice as powerfull as woodgas and no tars possible. The heat in the steam
keeps the charcoal plenty hot to sustane the burn.

The main reason for the resistance is because this foram is expressly devoted to
DRIVE on wood. One ingreedient, one pass, job done.

The main thing you must give your attention to is …Don’t Crash, and Don’t Hurt anyone.
I can imagine that if I were to just buy one of WK time proven trucks, I would have
nothing but trouble with it until I had 20 to 100 runs in it.

I’ve been a loner all my life. Without a good Master Craftsman to apprentce myself to,
I have always been aware of the fact that I am aways unshure If I am on the right path.
Sometimes, I have to reinvent the wheel, just to have the experience logged in and REAL.

build a basic and abuse it widely; find out what happens. Do it often Keep track of one variable at a time.
When a particular combination works well enough for an application, use it.
But keep an experiment going just to strech your understanding

                If it ain't Fun....Don't do it          Daucie
#5

Sigh. O.K.
Hi DaucieR the “gasification list” PeteS is refering to is not here on the DOW.
It is a whole differnet animal over 'thar somewhere else. Populated by the math 'centric guys and gals that firmly believe if you cannot pre-prove it in book listed maths it cannot be possible, or real. Participation there is like submitting a university paper for review or a theological exercise in angels and heads of pins.
You know, the kinds of people who can prove with known maths that a hummingbird hovering or a falcon’s stop-start glide flying, mid-air hoving as my birder wife pointed out to me recently would be IMPOSSIBLE by known aerodynamic principals. Ha! Ha! These birds been doing this easily observable by a common non-math 'centric person for a L-O-N-G time. Single oar gondola men and fish do this stroke thrusting too.
Charcoalers, blacksmiths and sword/knife makers had the open air principals of woodgasification all worked out well centuries ago with no math explanations needed. Early stationary gasifer enclosed hearth principlas were worked out trail and error, and with direct observation long before these were math “explained” decades later.
We must be a little easy on the math 'centric types because it is the only way they can really “see” and “feel” things.
Imbert type derived maths will not work for a charcoal pot WK system. AND these design Maths came about After a summation/review in the later 40’s, 'early 50’s of what the DOer guys had been doing that DID, and DIDNOT work in the previous 15 years. Ha! Ha! So back at it math guys! Now explain Mr Waynes speeds, powers, reduced fuel consumtion and output gases numbers and percentages! Need different formulas.
Practical comes first, math explains second.
Mr Daucie the thing I do see here on the D-O-WOOD is an acknowledgement just like the through the 1800’s stationary gasification oldtimers had learned, and the “new” mobile 20th century gasifiers fellows found out again, is it is just SO MUCH easier done with full cell wood based fuel stocks. “All biomasss” is really, really the toughest way to do gasification for motor fuels. Fossil “The black rock that burns” Coal was easier to useably gasify than any high AG mineral ash fuel stocks. Only Gas(ification) to Liquids is a tougher nut to crack. H’s and C’s not densly pack in enough. And too many raw fuel O’s to get rid of.

So long as the majority of the info exchange talk and developemet here is sensible treewoods based I stay. I’ve already wasted too many of my diminished years on the woo-woo, future fuels, save the whole planet as we know for everyone else stuff that is still pursued elsewhere. This is the talks on the “gasification lists” and at least three other active Internet forum groups available for anyone who really wishs to detail talk about these.
Good motor fuel charcoal IS made from raw wood fuel stocks. People with available treewood fuels can use this. Gary in PA and ChrisMO here have both built and driven wood charcoal gasified miles. Bunch other’s here wood charcoal gas home power generated.

Hey PeteS
ChrisKY’s explaination is absolutly correct without getting it bogged down with the energy balance math proofs.
Create a glowing HOT woodcharcoal bed and then use moisture containing wood fuels and you will create a compsite output gas mix with a higher hyrogen and methane content than a strictly charcoal gasifier.
In strictly Charcoal gasifing (all raw wood fuels gasifiers become this when ran out of new incoming woodfuel until then too also ran out of internal charcoal1!) fully vaporized heated STEAM is used as much to control gasifier internal temperatures as to drive up the hydrogen content. Too much steam will kill the process. If even only a small percentage of the steam H2O is diassociation this IS a HUGE benift to motor fuel power. This is mostly due to reduction of the atmosphere air needed into the system with it’s always resulting carried through nitrogen dilution into the final fuel mix.
India Institue of Science, Waynes AlabamaUniversity and two other “proprietary” developers have had thier system gases tested show a reduction on N2 final gasses mix from ~55-60% to ~45-50% ranges. BIG effect for engine power. These same sources using raw wood fuel once thier systems are advanced developed typically raise thier Methane fuel gasses mix percentage from a sub to only 1% to as high as 4-5%. THIS IS HUGE. As much motor useable energy there in the increased CH3/4 alone as in the first ~12-15% of the carbon monoxide in a woodfuel gasification fuel mix. This is on hands loaded engine proved. Math boy verified.

Too much fuelwood moisture, too much air-in moistures can easily crash the whole system due to thermal quenching.
The smart oldtimers would never, ever put water into their systems so as NOT to thermal crash them below a true gasification process; NOT get flash steam pressurization whooses and actual steaming expansion exposions; and NOT get the thermal stessed cracking in thier system materials. They used pre-heated fully vaporized steam! This is all in the old literatures.

Regards
Steve Unruh who still has never driven a mile on wood.

#6

STEVE UNRUH,
I greatly accept your Ass chewin’. …But realy, I thought I was saying the same thing.
Steam over carbon reforming is a proven and commonly used process.
But it needs very tightly controlled conditions.

If a mans goals are to fuel his truck and survive, then use what has the best record
of succes…The WK system seams to be the the best system we have to work with.

But, I am scientist, a searcher, …If you give me a “perfect” system, I will try to
improve it…Without that compultion and need, I would simply watch TV and buy what they
told me to buy.

I have a hard time understanding your language and train of thought.
I have to read and think, and then reread and think again, and then re read.

When all is said and done,You are probably my faverint person on this foram.
Mainly because your undersanding is so accurate and practicale.
And,I have to Work to comprehind your post

THat makes me pay speachial attention to you

Wk seams to have a near perfect unit, and we need to stear the want to be’s to
something that will work for them and not get them hurt.

Thows that Undersand must look at thows that donnot .
Sometimes you must look a person in the eyes and say NO.
I willnot give you something tha will get you hurt.

I don’t care how much your Want to be is,…If I don’t think your understanding
is up to the task,thin I willnot give you this Knowlege.

Hate me if you must, but I decide; and my judgment is finale.

I talk to eveyone about this energy bonansa but very few do I really
teach the way to make it work… I would never ask my wife to do this.

Just afew thoughts about this foraum; There are many, many people that WANT
to do this stouf but it takes a lot of falures to know how to make it work

If you cannot look at a failure and learn from it, then just buy an IPAD and go to sleep.

    Just my thoughts.... daucie
#7

Hey Chris,
That’s an awsome explanation of hydrogen formation, fast read and factual, thanks - learned alot from that one.

#8

I have put my trucks on display at events and people would asks how does the machine work? I would go through the long process as I have learned and memorized from Dr. David Branrby , Chris ,Steve and others . Going over the process near a hundred times and by the end of the day when asked, how does the systems work? I would reply “ VERY WELL”