How compressible is gas produced via hydrosis( steam+hot char/coal)

Hello all. First of all, greetings. I’m a bit of an interloper on this forum, having no active involvement with the topic, but I always enjoy learning something new about paths not taken or less ‘modern’ because one way or another the waves of industry passed them by. I’ve sometimes wondered how different history would be if the modern insights in permaculture, land management, and simple but efficient cumbustion had been the historical breakpoint before the industrial revolution. Perhaps we would be little less centralized and little more self sufficient than we are today. Congratulations on one of the more truly unique communities on the internet. :slight_smile:

Back on topic to my post: I am aware that the major reason that woodgas cannot be compressed and stored is that various trace gasses( primarily CO2 and methane) compose such a large portion of the gas, while possessing such a low compressibility, as to make make it a largely pointless exercise( without even considering the inherent risk of giant ‘kaboom!’). However, I also know that passing steam over/through a bet of hot char/coals produces a gas with a much more goodly amount of hydrogen; from what I can discover with my Google-fu, the percentages seem to range around the lower 60 percents of the final gas). So I was wondering( for my own curiousity, and perhaps one day, a bit of writing) if anybody has here has run the numbers or even does or knows on anybody who has done the experiments to find if the gas poduced from a simple, ‘built at home’ version of such a process is low enough in trace gasses with negative properties for compression and rich enough in hydrogen that this gas could be highly and safely enough compressed that it might be practical to compress and store it for use on motor vehicles( yes, I am aware that hydrogen can be produced via steam reformation of biogas, but then with a few modifications that biogas itself can be used to power and engine, so that largely defeats the point). What is the composition of the gas produced by such a process, and what are it’s properties?

Thanks in advance; And a very merry Christmas to everyone on the board! :slightly_smiling_face:


Hello Joel.

I have tryed that before. For a different project. Not wery energy efficiant.

The theoretical composition shuld be one part hydrogen, one part CO, volumetruc.

I think if l ever decide to play with gas storage, pyrolisis gas might be the answer. I produce loads of it in my charcoal operation and it has good energy density plus zero possibility for air to slip in with the gas, so no kaboom.


Hello JoelL,
Have you ever worked with the condensable gasses like propane, butane, any of the “R” series of refrigerant gases?

Have you ever worked with the non-condensable (at non-cryogenics temperatures) gases of methane, oxygen, nitrogen, helium?

In practical use applications the weight of the storage bottle MUST be factored in too.

Readily condensable to liquid gases only need thin walled, light weight bottles to hold multiple hundreds of cubic feet, or cubic meters of gases.

Even at thousands of pounds of pressure or multiples of 70 bars pressure you can only store a mere 60, 90, 120 cubic feet of non-condensable gas. And that requiring thick, heavy steel tanks. Very expensive fiber wound wrapped; forged aluminum tanks.

Compressing the non-condensable components of producer or bio-gas is not a chemical problem . . . it is a physics; energies-inputs versus energies-outputs problem.

Try it. Play around with CO2 to learn. Buy dry ice. Vaporize it in a collapsed bag. Compress it then to learn the why-not’s. Safe to play with CO2.
Play around with automotive AC system can teach this too. Use a pressure gauge set. Hand feel for temperatures alone the lines, before and after the expansion orifice. Listen to the engine loading down to compress to working conditions. Not as safe. Be careful about heat and cold burns.
Steve Unruh


Do you know what a gasometer is? This is a very safe way or at least a safer way to store the gas. However this will have low energy density pr charge. However there is a work around and that is using modern automation.

I am planning to start development on an automated system that would use two gasometers and a very simple gasifier. The goal is for the gasifier to produce a daily amount of charcoal for a charcoal driven gasifier for engine grade gas. This will not need to be very much as the point of using the gas directly with gas appliances will drastically reduce dependence on electricity usage. This would be more ideal and efficient as the gas used in these appliances is a direct conversion.

The gasifier does not need to be sophisticated nor will it need to produce clean gas. It just needs to produce good combustible gas. When the gas is charged into the gasometer it will cool and be under positive pressure. The tars and nasty’s will drop out fairly quickly. So you would use one gasometer for supply and one to accumulate and cool. When the charge runs out on one it will switch and I will automate the gasifier to self light and and recharge the spent gasometer. The boost out pressure I plan to use a very small compressor with a small compression vessel. This is only boost the pressure up as most appliances would require this and it will be more controllable with a pressure regulator.

For charging the gasometer all you have to do is lift the accumulator barrel. A very simple wench ran by a simple wind shield wiper motor should be sufficient if using barrel drums to construct this.

This is a high priority as Ive realized using the gas directly is much more efficient than running an engine, then converting to DC, then charging that current into a battery bank then drawing and converting back to AC. Then most AC appliances that use current for heat are not all that efficient in the first place. We also now have on demand hot water heaters, how cool would that be to run one of those on fuel gas you make yourself?? Pretty cool right?

So that is the path I plan to take. I would never ever compress this gas in a large vessel though. The compressor tank I will use will be the size of a soup can. The gas will be consumed at such a slow rate this should be sufficient and the compressor will be a small unit and still only ran at low pressure. That part I have to figure out yet, I will start with an RV LP pressure regulator to see what that presure for a starting point.

Edit: Quick google search rendered results of 11 inches of water or around 5.5 PSI for most appliance applications. Perfectly doable with a small compression tank and compressor. I might just use PCV pipe and create a steel vent cage around it for safety.


Hi Joel,
Storage is perhaps the central problem in most energy systems. Living systems produce carbohydrates and fats, no mean feat… But what of producer gas. I would suggest you look at the processes that produce LNG, CNG, LPG, Blau gas… I’m sure I missed a bunch of others.
There has been a push since 1995, when an article came out in Diesel Progress, North America Edition to streamline the process for synthesizing dimethyl ether. DME was identified as a good engine fuel by Haldor Topsoe in Denmark, during world war two. The main proponent of DME at the moment seems to be Rebecca Boudreaux at Oberon Fuels, In San Diego.
DME compresses to liquid ~75psi. It can be used in minimally modified diesel engines if 6% oil is added to increase its lubricating properties. Existing propane handeling equipment can be used.
I’m with you, decentralized power is democracy. My pipe dream is to see DME produced in small quantities the way bio diesel is. But that would be NO mean feat.


Hmm - perhaps the 60+ percent that keep reading about stemmed from the combination of the two - hydrosis of the much cleaner and more energy dense gasses released by pyrolized charcoal? :thinking:

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DME is very promising diesel substitution. Another good point for it is that proven synthetization raction is based od 1:1 mix of carbon monoxide and hydrogen, which is easily achievable by wood gasification. Main drawback is that on the way you loose 3/5 of energy stored in the wood. Which leads to very unfavorable economics end resource utilization. I tried to compute are needed for poplar plantation to cover Czech diesel consumption and came to the figure around 2 milion hectares or 5 milion acres.

Not feasible even if excess heat would be recovered for district heating


Dear Joel,
Welcome to the forum.
Before you write about this professionally, please take a course in chemistry.

Pyrolysis is the heating of something in the absence of oxygen. Seeing as charcoal is basically carbon with trace amounts of ash, if you heat it you just have glowing carbon. No gas.
Blau gas is glowing carbon exposed to super heated steam. So you could “pyrolyse” carbon and release 700f low pressure steam into the bed of orange/yellow coals. This would give you hydrogen and carbon monoxide. This is the fuel the Maybachs burned in the Zeppelins. It was neutrally buoyant so the crew didn’t have to vent hydrogen lifting gas as the engines consumed fuel.

You better define “compressibility”.

There is a lot of mythology surrounding compressing “wood gas”. Airgas will sell you a tank of compressed carbon monoxide. They also have tanks of hydrogen available. Its not theory, it’s a case of energy density.
The reason we do not compress Woodgas is because it is more efficient to store the energy of wood in the form of chunks, rather then gas.
A good quality, fully loaded, air-cooled, lubricated rotary-screw compressor consumes about 16.5 kW of power to produce 100 cfm of compressed air at 100 psi.
Let’s say there is 2000 watts per pound in 20% moisture firewood. I think you can see immediately, that it takes over 8lbs of wood to compress 100 cubic feet of gas. Using your constraints of homemade equipment, you would be carrying a butt load of wood to make the power to compress the gas. Energy density is too low. Energy expense too high! Desperation level off the charts…
And yet, I am building the Blau gas benches compressors, and tanks, to make the gas and store it.:roll_eyes:


the compression of wood gas is only justified in such a way that the subsequently invested work is used in the expansion process, either indirectly through the expansion engine, or as a direct injection in front of the upper dead position immediately before ignition.


Right on Tone!
In America, we have too many other less expensive ways of doing things.
I do enjoy this topic, and am grateful it survives in the armchair universe.


Hi Guys,
At 4:12 in the compressed air engine video there shows a multibladed fan blowing across the scooter? engine. Shows heat absorption fins stacks around the motor housing. He is using ambient air heat to keep his engine from frosting up.

Ever heavy use compressed air tools year around? Sure, you have.
Great in the summer for cooling down your hands. Terrible cold on the hands in the winter.
It snowed here last night. Today we will travel 22 miles to my sister’s house for an early Christmas time get together.
My wife would object greatly having to bundle up herself and the two girls to make that trip in a Mr Di Pietro make-colder-yet car.
She would object mightily to going back to 19th Century bundle up with a hot water bottle for winter traveling.
Mr Di Pietro by throwing away the past loses the perspectives wisdoms to be learned.
Being relearned now by the new production all electric cars. Gasoline/electric hybrids can windows defrost, interior heat quite well. I’ve snows driven these. All electrics must sacrifice range driving energy to do this.

And we will drive pass in those 22 miles, at least two automobile accidents white cross death sites. Be stupidly passed on blind river road curves by modern-speed-addicts, dangerously, at least 2-3 times.
My wife insists now after being hit twice in the last 15 years to mass-up her vehicles to survive modern driving conditions.

Steve Unruh


As a friend of mine will often say ( life time cdl truck driver, daily driver nothing smaller then crew cab long box f450, usually f550 or f650 or Kenworth t800, all extremely slow lumbering giants) I am bigger, I will win.


Blau gas ( German: Blaugas) was an artificial illuminating gas similar to propane, named after its inventor, Hermann Blau of Augsburg, Germany. It was manufactured by decomposing mineral oils in retorts by heat and compressing the resulting naphtha until it liquefied. -Wikepedia-


Thanks Rindert,
I will dig out the old industrial chemistry book I have on it. I probably mean water gas.

BTW , Blau gas was only used in the Graf Zeppelin, Not any others.


*Reads Bruce’s message and sits straight up * “That’s what it’s called!” *Furious googling and wiki reading ensues *

Okay - the basic idea that I was thinking of was apparently an inefficient version of the Nitrogen free ‘blue gas’ water gas process developed by Sir William Siemens in the 1850s. I say ‘inefficient’ because the proper process alternated air and water to account for the competing endothermic/exothermic nature of the reactions. And my primary interests in this line( for curiosity and possible fictional, not professional, writing in the future, btw) of high hydrogen/low to zero poisonous carbon monoxide content seems to have been served by the carburetted water gas process developed in 1875 by Thaddeus S. C. Lowe, that consisted of exposing said blue gas to the products of thermocracked oils and was apparently a major foundation of the development of the modern petrochemical industry. If I understand correctly, the increased hydrogen output and elimination of Carbon Monoxide was due to the introduction of pressurized steam and efficient chimneys, with the carbuerated oils merely increasing the luminosity and heating value of the gas?

With an input air to output Hydrogen ratio of six to five, this looks like a mighty worthwhile process to pursue for a stationary gas generator. I would bet a nice sum that the process could be reduced to few if any moving parts on a home build with careful design and use of pressure. If nothing else, it sounds like it would be a blast of a build to tackle for someone who has the means and opportunity to do so.:slightly_smiling_face:

And while compressed hydrogen may be a less suitable pathway for homebrew storage than bio oil, it was very good for distributed gas heating and lighting before it was displaced by natural gas, and it certainly does tickle the speculative nerve about just how much scientific theory and industry is necessary to get what results, considering what the Romans and Chinese did manage without a fully modern version of either. :wink:

BTW, serious thanks for the proper name, Bruce. It seems that it’s ridiculously hard to find just that information for the process that you’re looking for online if you don’t already know exactly the right name to search for it!


Dear Joel,
I got my degree first in chem eng, then switched to mechanical engineering. I went to Michigan Tech. I worked in the Van Pelt Library. This at a time when the library was undergoing a transition to digital resources. They were “discarding” all the 19th century engineering texts. I carted all those home. I learned about Steam & Gas engines from the original source material. The original gas engines worked on producer gas and didn’t really start to use natural gas until the beginning of the 20th century. All this education took place about 15 to 20 years ago and I’m going to have to beg for forgiveness because I’m starting to forget things. One of the things that I do remember about making the water gas is that the benches, which were a series of gas producers, did not last very long in service.
The things that you’ve written in your second post all soundtrue. It’s funny how memory works I can’t remember what it is but I know what it is not.
Please look up Sir Harry Ricardo, and his two books on gas engines. They are the seminal works about efficiency and construction of gas engines what he wrote about before world war 1 still is true today 100 years later and sadly we haven’t invented anything new since then. I will write more later but I have to leave it there for now.


I love those original old books, because they are written in plain language you can actually understand. Thanks for info on Ricardo. I’ll know what to look for next time I prowl a used book store.


JoelL in the years 2017 and 2018 I sourced out ant read all of the modern era We-All-Fall down story authors.
I was looking for those authors able to see in-dire-straits that DIY woodgas was a way to keep engines running for water pumping, electrical generations and refrigeration.
Poo. Poop. What an ignorance.
Only one author, in one story: John Varley - “Slow Apocalypse”; had woodgas found and used multiple repeatable times.
Only one other author even mentioned it once as a temporary make-do possibly. Until . . . a Wind and Solar local Grid could be built and developed.
Not even excellent writers like Forstchen - “One Minute/Month/Year After” series; Bernard - “Cascadia”; or Kunstler - “World Made by Hands” series even mentioned woodgas.

Yet every single one . . . every single one, premised from cold, cold upper Mid-West USA; to Florida; to upper New York State and Maine; to the forested Pacific NW all used site sourced wood for direct space heating. Direct use water heating. Direct foods cooking.

Took me a while to see the patterns why woodgas was story lines, not-used.
Oh, yeah. I know well why the vast majority of writers; Doomer or Futurist, are woodgas shunning now.

So, hey man. Become the writer who does better, eh.
Steve Unruh

Rindert, I am not sure if this will work. I included a link to the Ricardo books. I photographed them long ago. At least, you will know what you are looking for.

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My 2 cents experience…

OP, yes gas is compressible, with a cost

If done right you can make “any kind” of gas, based on gasification, with or without kaboom risk’s

Again, that also has a cost…

Any gas you can make, compare it with CNG, how big/small is the tank, what is the compression cost to compress it into 240 Bar… add all the costs

For any DIY setup… much to expensive… much to dangerous…

Best way : as Kristijan, stage 1 = the pyro gas from the charcoaling process, stage 2 = charcoal gasifying
And the 3 th = charge your electric car with charcoal generator…

If you live in a cold climate, then build a stationary home heating system with elec generating added…

So much you can think off, so much that can be done…

However, it starts with the basics of the question, your question…
Build the smallest setup thats possible ( Charcoal based on Gary Gilmore )
The start to add water etc… the experience you get with the doing will give you a definitive answer.

To all: Miss you guy’s, sorry for so little contribution from my side. Stay safe out there