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

Joel, l belive the water gas needs to be furter refined in order to obtain pure hydrogen. I belive CO is oxidised to CO2 wich is then scrubbed out of the gas.


Hi Joel,

I think that this is the misconception from the OP , what makes confusing.

"CO2 and methane) compose such a large portion of the gas, while possessing such a low compressibility, "

Methane , AKA CH4 , is a potent combustion fuel for our purpose.
Co2: is kinda always present, lower % the better.

All gasses are, per definition, compressible, might be less effective, but compressible.

The only gas that is really unwanted or favorable in lowest quantity possible ( be it nearly impossible )
is Nitrogen…

This Nitrogen and Co2 are the 2 gasses that takes down the “power value” of the woodgas.

Kaboom ?
Once had that nickname, for obvious reasons, but… combustibles without oxygen are at low to no risk to explode… bear in mind however: H2O is a good supplier of both oxygen and Hydrogen…

Google -fu… i like that…
G’Fu this: Biogas = CH4/Methane… but always comes with a huge % of CO2 and H2S

CH4 is better suited for our purpose of energy generating than Hydrogen… CNG , LNG are both CH4 …


Yeah, that Sounds right.

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Here you go JoelL.
Study a writing master:

Be sure and read his lead-in introduction.
Be sure and read his finishing afterword.
Most do not realize that RobertH. was a Naval Academy graduate Engineer and did service on big naval ships. Big ships means big power. All real Powermen know Big-Power can make for big problems. Doesn’t matter . . . steam, gas turbines, wind turbines, hydroelectric, big battery banked, petroleum refinery, natural gas.
Also, RobertH. spent his years WWII right after this story working as an Engineer in munitions research plants.
Steve Unruh


Great story.
I was getting an adrenal rush during the read since the risks seemed so real.


It’s an interesting question.
I think the short answer is ‘no’, there isn’t much pursuit of a medium heating value syngas in the DIY crowd. Excluding the physics issues others have pointed out, chargas is maybe 4 MJ/m3, wood gas is maybe 6 MJ/m3, definitely not worth compressing.
If you could get to 20 MJ/m3 like retort made ‘town gas’ it might be worth it for stationary systems, but probably not for vehicles.
(Natural gas is 36 MJ/m3 for reference.)

It would be possible to do steam gasification at home if you were brave/foolhardy/careful and really wanted that medium value gas.
The Wright-Malta folks built some laboratory scale systems that are well described and appropriate to home experimentation. The context was syngas to methanol but the steam gasification is well documented:


Besides the medium value gas you end up with, the steam gasification is truly feedstock omnivorous and solves the gas cleanup.
But you need to be comfortable with 200 psi steam in a vessel and heat to 1100 deg F. Not terribly difficult in smallish batches with electric heating and insulation and some stringent safety protocol… but worth it??


Very interesting gasification process, but obviously with the devils in the details.

First of all: alkaline catalyst. If not cheap abundant stuff like e.g. lye, the whole thing would be busted.

Second: pressure inside the vessel. Acording to paper, there was 15 pounds of wet wood with some more water (together 12 pounds) in a cylinder of around 23 gallons. Vapor pressure of that amount vastly exceed 400 psia before wood even reach the temperature of decomposition.


I think the ‘alkaline catalyst’ is code for ‘wood ash’.
Yeah, regulation would be necessary, but you wouldn’t need a compressor.
I’m not promoting the project, mind you, just filed it away under ‘what’s possible’.
Eating anything you feed it is a nice feature, and the energy balance is attractive.

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Just read @Matt thread on gas storage and thought there was some interesting cross over between the subjects.

A home steam gasification vessel operated in batch mode, feeding a gasometer with 20MJ/m3 gas, (without a blower) is certainly an interesting way to solve the energy storage issue for reliable domestic systems without using a battery bank or long run time engine/gasifier.
Let’s see;
** You get to skip the charcoal making problems of open flames, smoke, grinding, screening and heat recovery (assuming char-gas for small engines).
** You get access to all the low value biomass otherwise unusable for gasification.
**The higher energy content gas means you get to use a smaller storage unit.
**You get built in gas cleanup
**You have a reservoir of engine grade fuel gas (super convenient)
All for the low low price of an untested pressure vessel and it’s regulation and controls:)
Yes, we just re-invented ‘town gas’, but hey…


Yup you get it :fire: … …


You got everything right except one thing this is going to use on the market already tested systems for this tank. The tank is not there to store the gas for long term storage. It will be there to act as a buffer, it will only be a pint or one liter in volume and made out of PVC using friction caps at each end. This is tried and true as this is common in HHO systems ( my self included and is what Ive used. There will be a diaphragm pump that will supply line presure, the tank is so that it can not over pressurize. Think of this pump like your fuel pump in your car. There will be presure switch and as soon as the appliance calls for gas it will open its solenoid valve dropping presure triggering the pump to turn on. If the line presure goes over 5 psi it will turn off.

The alternative is to add a return line and run the pump with a static regulator; not sure how to do that with gas yet.


Hey ChuckW.
You said Towne gas making.
They of course primarily were concerned with the cleanliness and energy density of their for-sale fuel gas.
So back then water washing and cooling just made sense.
But every single Towne gas making site became a toxic hazardous waste dump.
I know. I once was part owner in an auto-electric business in SE Portland within sight of one of the remaining open frame floating gas storage-pressurizing structures. The crap they washed down into the Willamette River . . . 19th Century high-tech. Piped in lighting progress.
OMSI is sited there now. They know. They Know. Lower Willamette and Columbia do not stir dredge the edges!

Even as a kid growing up in the 50’s with the chore of barrel burning the household trash
nearly all of the long-term lingering nasties were concentrated solids we’d haul away to a land fill. That was far from perfect with the air stink burning. 20th Century simple tech concentrating. There was no Rural garbage services.

WE are 21st century and any water gas cleaning need to have a water treatment complexity added. Factor that in from get-go. You don’t and other will force it onto you.

S.Job’s pocket miracles since 2007 ensures e-v-e-r-o-n-e has cameras on-person now.
And the be-your-own-publisher social sites of youtube, twitter , tic-toc, and others has too many looking for their spotlight time.

Woodgasing done best practices only makes solid wastes ash, with just wee bit of heavy tars concentrates. The collected condensates are one a mild bio-degradable herbicide. The other a mild bio-degradable fertilizer.
Steve unruh


Good point Ive been thinking of this.


@SteveUnruh Yeah, the retort coal gasification of historic town gas was very dirty, eh? Hydrogen sulfide, various other sulfur compounds, heavy metals, etc. Very dirty indeed.
I worked as a import mechanic in Selwood around '95, wonder if we used your shop.
According to the Wright-Malta paper, it looks like steam gasification of biomass at 200psi and 1100F would have very little residue. No tars, very little char, mostly ash. Clean enough gas to feed directly to a catalyst for methanol synthesis.

@Matt I was thinking of the high pressure vessel described in the Wright-Malta steam gasification paper . 200 psi steam with significant super heat at 1100F.

Every feel your brain melting down as you stand staring as a gigantic pile of chips or slash , mentally juggling all the variables trying to find the best path to a long term viable system that puts such resources to work for you and yours?
We’re in the middle of a 40 acre commercial thinning project. Soon to be thirty foot high piles of slash dotting the landscape. A hundred acre woodlot and the old folks burn 400 gallons of oil a winter because it’s thermostatically controlled (along with 7 cord of wood).
A hundred acre woodlot with more wood rotting each year than we could ever use and still need hundreds of gallons of diesel each year for farm operations.
Human nature being what it is, if you don’t adopt a system with enough convenience and obvious long term benefit, it won’t be used.


And that is where I feel woodgassers stand out of the crowd, a hardy group not afraid of hard work and a little gunk under the finger nails. Ha, from my own experience, life is not convenient. Don’t mind if I take my time at my own pace to do as I please, and driving a little slower on woodgas suits me just dandy!


Ah ok you are brainstorming your version. Perfect!! thats what its all about :fire:


@Matt I’m on a similar track as you, sans gas storage. But yeah, capturing pyrosis gases from char making is very intriguing.
Steam gasification was just a possible answer for the OP, not something I’m currently pursuing.
I haven’t figured out just how I’m going to capture the charcoal making heat yet so I very much appreciate your efforts.
I’ve leaned toward long run time generators instead of significant refined energy storage.
Store your energy as charcoal, trade engines for batteries.
Iron, oil, and spark plugs for lithium or lead.

I’m at a very reliable 11 hours run time, 10Kw/hrs and 33 gallons of softwood charcoal with a far from optimized co-gen system.
I think you could reasonably, comfortably, orient your off grid life around that.
The rest is ‘just’ fuel making and management. Call it 250 gallons a week, 1000 a month. That’s a box 4x4x8… same volume as a cord of wood.
I’m currently thinking a small battery bank is necessary for almost any off-grid system. You are gonna want it anyway for 24/7 power and you get to supplement with solar.
I think you are correct to try to eliminate as much electricity reliance as you can, but a modern refrigerator uses very little and is the cheapest off the shelf option…


Yes exactly. Yeah I dont know about new refrigerators but my RV fridge will smoke my battery bank in a few hours time. But a 40 lb propane tank will last two months. Even if if the fridge is more efficient on electric its still a huge loss. This is because you lose 75% of the gas energy potential when you convert the gas to electric in a engine power generator. So it is still a huge efficiency gain to use gas over electric in this scenario. Besides you want to use that stored gas so the system produces enough daily charcoal. So balance will need to be assessed in order for it to be sustainable.


For anyone with deep chest freezers you can modify them into more efficient fridges with a temperature regulated PWM. I can’t remember the brand exactly but there’s tons of videos on it. It will cycle the freezer down to use less power, and the chest format helps keep the cold inside even with the lid opened occasionally. A regular fridge loses a lot of its cold even from short opening.