Hi, Everybody

Small Engines Charcoal Gasification
#121

Thanks for the info- just reading up on Carbon Black, most of it goes into tyres, so landfilling tyres is actually a carbon sequestration mechanism. I’ll bear the possibilities in mind, but handling the fines is a messy process, and perhaps not the way to stay on good terms with the neighbours.

A nice little breakthrough today- I got the little Kawasaki suitcase, the one that I’d given up on as too puny to get a good gas flow, going on charcoal. It turned out that the hose I was using was too long and narrow, and using much larger (about 40mm ID) was the answer. I managed to get in two 1 1/2 hour runs on about 9 litres of char each, loaded with a 500W halogen floodlight. Details as I remember them- the nozzle was one of the cordierite kiln props mentioned in a previous post- the drawback is poor mechanical strength, and it broke off when I took the tuyere out, so I’ll need to go fishing when everything cools down. Conspicuous by its absence is exhaust gas recirculation- it didn’t like it, at least not the crude lash-up that I tried. I suspect that I hit it lucky, and under all the conditions, it stabilised itself between orange and yellow- around 900C. I did spray a fair bit of water down the tuyere, with a definite change in the engine note- more hydrogen? Starting- I had to prime the gasifier with a fan blowing down the tuyere until I got a stable flare at the engine air intake- after that it started with one pull. The runs finished with the engine just stopping- I was hoping that the exit pipework temperature would give me a clue, but it never rose above about 60C- the water in the jacket stabilised at about 70C. The second photo shows the current gasifier design- outlet pipe on the left, tuyere in the centre, and filler on the right- I’d originally hoped to do everything through one orifice to reduce the amount of gas-tight welding required, but this setup should make filling much easier with less downtime.

One other thing- I mentioned the TLUD stove with the stackable burn pots in another post- I fired it up again after focussing on the tunnel stoves, and got really good results with wood pellets- nice dense pellets of char, very little processing required, not much fines, almost smokeless, and very little operator intervention. To be pursued…


2013-10-06%2016.00.54.jpg1024×768 158 KB

#122

Hi Brian,

Your set looks really cute and simple, happy for you that it make the small kawasaki run as well…

keep up the good work i would say

#123

Back from holiday, and spent a damp day or so processing charcoal, screening it from 10mm down to about 1mm- probably too fine- I normally blow down the tuyere to gauge the airflow. I’m looking around for a 3mm screen, and use anything finer as biochar. I’ve bought a bouncy castle fan, which hopefully will power a dust cyclone, and clean up a messy process.

I did get in one flare run, with, for probably the first time, a pure blue flare, which I assume means pure CO, which in turn means good, dry charcoal- does anyone know otherwise. I assume that yellow=hydrocarbons, and pinkish=hydrogen. The run finished early when the kiln prop tuyere end fell off. Again the question: is there a sweet spot temperature that’ll crack water or hydrocarbons, but won’t melt a mild steel tuyere?

One little surprise on renewing the insurance on my Fiesta- I asked if they would insure a biomass gasifier, expecting a reply along the lines of “No, because it’s too technical for us.” I got a reply of “No, because it involves a process over 700C.” I was gobsmacked, as well brought-up Brits say, that they even knew about gasifiers- which means that someone in the insurance business has assessed the risks.

#124

Hi Brian, Please do your engine a favor and put a filter in the line taking charcoal gas to the engine carb. The fine dust sucked from the gas generator will eventually mess up your engine. The “sweet spot” for cracking water into H2 and O is referred to as the water gas reaction. It starts at 400C.
Love that word “gobsmacked”. Got to add that to my vocabulary.
Keep up the good gassing!
Gary in PA

#125

Hi Brian,
Join the club of blue flares :wink:

About the sweet spot;
Since we gasify Charcoal, meaning high carbon content fuel, this carbon starts to convert at +/- 650°C and is fully sublimated at 4000°C
Having a blue flare does mean ideed a high grade charcoal with only little impurity’s
Still you can have a high content Co2 , which would be practical invisible, depending the conversion rate.
If the carbon reacts with oxygen, it produces heat + Carbon dioxide, and in the next step this heat + carbon convert the Co2 into Co
The higher the temperature, the higher the conversion rate.
This is called the “Boudouard reaction”
Adding water to convert it into Hydrogen would take the highest temperature range as possible to avoid the increase of Co2 and the premature diluting of your gas.

my suggestion for the nozzle would be: use a high carbon steel if possible, (steam pipes) and ad a porcelain / ceramic tip at the end.( from a fuse )

I did noticed with my trials that the nozzle size does matter a lot, the air intake by the nozzle should not be more then 60% of the amount of gas needed in the engine.
it does make your gas far more rich and the less Co2 in your gas, the easier your engine starts.

I am working on a few detailed spreadsheets with my findings and will post them as soon as ready.

Regards from Thailand

Koen

#126

Hey fellows let me step in and mediate this question a little bit.
Both explainations about converting water into hydrogen are correct.
You can search up and find good serious literature about the high temperature and high energies needed to do this.
You can search up equally good serious literature showing you can make up free useable hydrogen from water at as low of temperatures as 350C (662F) and even as low as 190-210C and this will even give off a little heat and be exothermic.
I do this woodstove heating every year for a high percentage of the annual 5000 hours of my annual usage. My previous blue and purple/pinkish flames in my airtight woodstove avatar photo.
The differences are under the influence of iron oxides, chomium oxides and other traces acting as reaction catalysts. Our containers. Our nozzles. And especially our fuel stocks. And IF you are adding Ground sourced water ALL of these are putting these traces into our reactions. The same wood and especially the same rapid uptake grasses/bamboo spiecies WILL uptake and store different soil/ground water metals and mineral salts when grown in different soils; or even the same soils, at different times of the year. This will carry through in your woodchars!!
WE CANNOT ELEIMINATE THESE EXCEPT IN VERY ARTIFICIAL SERILE EXPENSIVE LAB OR INDUSTRIAL CONTROLLED SITUATIONS.

I am a direct action/results kind of guy. I only care about what will make MY IC piston engines run with the best power and the least expense and fussing around. They run poorly on blue flare gas - done it. They run poorly on purple/pink flare gas - done it. They love the high carbon soot rich yellow flare gas as in my latest avatar photo. As dedicated designed Atmosphere mixed gasses breathers IC piston engines will happily run on up to 50-60% inert nitrogen, carbon dioxide or argon as long as the rest is some form of combustible hydrocarbon mixes and oxegen. These other inerts with high specific heats act as excellant thremal expansion gases for the piston engine. Act as very good combustion rate Down moderators for IC piston engine PITA too-fast hydrogen fuel gas. Hydrogen fuel gas itself acts as a combuston rate UP moderator for PITA too-slow carbon monoxide fuel gas for the IC piston engine.
Only real in this world common man usable results counts here on the DOW.
Results are going to vary hugely accross the world and even for you at different times of the year, with changing conditions, and as you cycle in and out of different base fuel stocks. Why to keep a HUMAN in the operator loop! The best of us will just tweek and adapt to keep that engine shaft turning out power for a purpose.
Don’t have to make better humans - just have to give them back real accomplishable tangible challenges and control into their lives.

Regards
Steve Unruh

#127

Gary… the setup in the photo does actually have a chunk of sponge stuffed into the sleeve where the blue tube feeds into the carb. I hit it lucky with a lot of things in this lash-up, and I need to build a better filter and get the element of luck out of it. The way I’m leaning at the moment is to get the combustion zone temperature as low as possible, so that I can get away with a simple scaffolding pipe tuyere, and put a condenser and liquid trap on the output to monitor what’s getting through- is it a safe assumption that if it cracks water, it’ll crack anything? With that particular engine and load, and no exhaust gas recirculation it settled at “orange” on the Metcolor table- somewhere between 800 and 1000C. There was a distinct change in the engine note when I sprayed water in- hopefully the lambda probe will give me more clues.

Just for a change, I tried out a variation on the two barrel char production method, only scaled right down to 25 litre drum size. Setup was amazingly fast- cut slots in the bottom of one drum to make a grate, cut the bottom out of another and a couple of secondary air slots to make the afterburner, load it, light it and leave it. Shutting down was easy-clip the lid on, lift it with one gloved hand, and set it into a third drum to seal off the bottom air. Let it cool and pour it into a sealed holding drum. It helps that the factory next to where I work are disposing of more of the ring-latch drums than you can shake a stick at. The results- batches 1 and 3 were great, batch 2 was horrible, full of unburnt wood. Remember, I’m using sawn pallet wood, and it looks like there’ll be a bit of skill and judgement in the loading. Sawing and prepping took significantly longer than with the tunnel stove, but the actual burn needed less intervention. Practice makes perfect, and I’ve got more options- I want to try it with woodchips. I’m trying to get a couple of local blacksmiths interested in forging with charcoal. To be continued…

#128

Batches 4 and 5 using the 2 barrel method- becoming disillusioned- no disrespect to anyone who makes it work, but it’s not the best method for my feedstock, lengths of sawn softwood pallet scrap, for these 2 batches 2" x 2". Stacked upright, they shrink across the grain, allowing a draft all the way up from the grate, so you can look in and see simultaneous yellow hydrocarbon combustion and the black gold burning away in primary air. Hopefully I’ll get better results with chips. For now, I’ve got about 60 litres+ of gasifier charcoal stockpiled after an extremely messy day crushing and screening, and about 50 litres of fines, which I need to drum up interest in.

To do list: build a demo setup using a quieter Honda suitcase genny, Build a better gas filter, and get the genny starting reliably on LPG so that it can prime the gasifier, and be weaned onto char gas.

One spin-off of charcoal- the fines can be used to bleach Pepsi Cola. Perhaps the day has yet to dawn for this application.

#129

Other Brian H: Somewhere I saw a thing where a guy mixed charcoal fines and sawdust 50-50 in a slowly spinning angled 55gal drum. If one slowly drips oil or tar into the dust as as it spins, they “snowball” into dense lumps of concentrated fuel. I believe Gary G. has added a few into one of his charcoal/hybrid gasifiers with success but I can’t find any info on them anywhere. Worth a try.

#130

@Brian Ham… I’ve seen the page, and searched for “puffergas fireballs”, but the page seems to be down- have a look here:

http://www.woodgas.net/jeff_davis.html

I believe he used starch as a binder. Ultimately, though, Plan A is to get my fines back into the ground as biochar, do my own carbon offsetting, and ignore the “Carbon footprint this, carbon footprint that” operators. The guerilla approach would be to flush it down the toilet so that it ends up in sewage digestate and back on farmland, and I was out of the country and in a coma when I didn’t even think about that approach. Oh, and the local sewage farm burns it’s digestate.

Alternative char production methods… I can’t wait to try this method, and watch the neighbours’ eyes light up with glee:

1 Like
#131

Hi Steve,

Your statements are correct, but…

The reason why i choose/prefer the higher temperatures is to avoid that the sabatier reaction takes place.
carbon dioxide + hydrogen gets converted into methane and water, exothermic reaction yes. any catalyst, depending the feedstock as mentioned by you, will increase the effect depending the temperatures.
using temperatures >1000°C reduces the production of Carbon dioxide , converts more Co2 into Co , ergo less methane, less water,

We could debat which is more desirable, i agree on that point for 100% ( the point of debating of course :wink: )

My question would be how much energy can we gain from the sabatier reaction and how to use the energy from the exothermic reaction ?

#132

Good Morning KoenVL
I have been mulling for days how best to respond to your question, “. . . how to use the (heat) energy (that will be produced by) the exothermic reaction . . . from the Sabatier reaction . . .” as it internally produces methane and water?
Here are my dilemmas:
In a raw wood gasifier this is never a problem because the thermal-chemical REDUCTION reaction is so hugely endothermic you will not even see the bit of Sabatier "heat"produced. And even be very appreciative of to 1%-4% methane fuel boost produced. Never even notice the little extra water added when we are already set up to deal with an minimum of 20 to up to 40 unit weight of moisture/condensates already for evey hundredweight of raw fuel wood we put into our systems .
My dilemma: WE ARE NOT in a raw woodfuel section of the site but in Gary Gillmores hosted Charcoal Gasifiers section.
You charcoal guys are alway dealing with metals, even ceramics killing temperatures being heat driven up. How to bring these down.
We raw wood fuelers always trying to systems intergrated produce enough Heats to get up to, and maintain Temperatures for favorable reactions. How to hold in heats. Even bring more heats in from the engine itself.
More difficult than that my responding in this Charcoal Gasifier section is we are not even on one of your own started topic threads but on Brian Hughs personal project topic thread.
Anything further I would say could easily be construed as discounting his work; or even as a personal attack.
But . . . say nothing; then am I being an Internet “hit and run” Troll?
And almost anything more I say then I WILL be Debating.
It is the clearly expressed goal of the Owner here; the Admin here; and those of us agreed to be specialized sub-site Hosts to keep it Today: Now: Real World Engine applicable; with the site named Demand that all works are actually “Drive” (in American english this means equally as well “to power”) spark ignition piston internal combustion engines for a useful purpose. No more of the endless running in circles debating we are now all up now sickened with in the last 5 years with NOTHING BEING BUILT! NO ENGINES BEING FUELED AND RAN!
Everybody so far participating on this topic thread HAS been self-made fueling, and running IC piston engines. Good jobs KoenVL, BrianB. and PatrickJ.!!

So . . . . to not to have troll tag hung on me. Sometimes in Life you are damned both ways you would jump . . .
I will stick by what I said above that at the temperatures we ALL working with that it is impossible to isolate the the container metals molecular spewing off with catalytic effects that we will ALL have.
In my current avatar picture the lower glowing hot woodchar is sitting on a cast iron grate and the heat is degrading out iron with some chromium, molybenum, and zinc molocules, hot, free and reactive. The center of this now 20,000 hour in service cast iron grate has a big heat eroded hole plugged now with an alumia-ceramic thermal brick slowly being now heat eroded away. Hot reactive free Aluminum molocules!
The upper visble gasses combustion flare is being 1000C pre-heated air fed out of a stainless steel supply tube assembly that slowly erodes; thinning, needing occasional repacements. So more free, hot, reactive iron, chromium and nickel shed molocules up there also.
And this does not even account for the always trace metals, minerals effects contibuted from the actual fuel bases in the woodchar.

ONLY in a tightly controlled LABORATORY Glassworks situations can you selectivly isolate these different reactions.
We raw wood fuelers just go with the changing variable combo reactions; averaging out overlapping gasses produced flows and engine run with it.
Some charcoal guys think that you can more purist isolate out and address one thermal-chemical reaction at a time. Not gong to happen.
Gary Gillmore, David Bailiie and others know better. They take the average/blended reactions in a charcoal gasifiers also and let the actual engines power results be the proof of the pudding.

Best Regards to All
Steve Unruh

#133

Hi Steve,

I am having a grim al over my face now… :wink:

I agree with you up till one point :wink:

Raw wood fuelers can’t run without the charcoal they produce in the combustion zone…

Raw wood also gives you the benefit of the oxygen in the fuel ( not have that in the charcoal )

Being able to run with charcoal, does not automatic mean that i am able to make engines run on Raw wood fuels :stuck_out_tongue:
But, i am learning…

My guess , its the same as learning walking…
If i can’t do with charcoal, i will never learn the raw wood…, but if i fully understand the processes taking place with charcoal, it will help me to be able to run on Raw fuells…

To the methane content in a raw wood gasifier, the correlation between Co2, Hydrogen and methane is given by the temperature and moisture, the dwell time in the reduction zone does the rest.
The open top, multiple burner-stages as Mukunda proclaims, does the best job as far my knowledge goes.
My guess that the WK works on the same principles… with some sweet adendums of course.

#134

Hey Brian, I read your post last night and happened to think about this evening when making a batch of charcoal. It hit me that you may be missing an important step. About half way through the burn, you take a long stout stick and take off the chimney. Lay the chimney aside and using the same stick, poke around in the retort. You will be pulling the uncharred wood away from the relatively cool sides of the barrel. Takes about 30 seconds, then use the stick to put the chimney back on the retort. Also, if the fire comes to one of the openings at the base of the retort, cover that hole with dirt. This will force the fire to move to another hole to find oxygen. Both of these are important steps that may not have been well communicated
Got to love that charcoal.
Gary in PA.

#135

@Gary… Got to love that charcoal, and the way it draws you in, and watching other people get drawn into the process- I’ve always been interested in process technology. Your points were well made- I’ve had a flame front moving down nice and evenly with wood pellets, and I was able to stack the burn pots to get a continuous burn with very little intervention- but it ain’t gonna happen with sawn pallet scrap in 25 litre drums. Another option might be insulating the burn barrel. It’s a small step away from Load It, Light It, Leave It, but still a damn sight better than a ring kiln. The question is: what’s the maximum size of chunks that would happily char in a 200 litre barrel? I spoke to a tree surgeon today with a bigger supply than demand of softwood scrap, and I’ve got my thinking cap on…

@ Koen and Steve… Do I understand the debate to be about whether or not a small amount of hydrocarbons in the gas is a good or bad thing? My own thoughts are that tame hydrocarbons- at the level of propane or butane- are harmless, and actually closer to the fuels that the engine was designed for, as long as there’s nothing that would condense in the inlet system. My own game plan is to reduce the combustion zone temperature to see if I can get away with a simple mild steel tuyere, and hopefully prolong the run, and in the fullness of time, use it to clean up the vapours from a wood gasifier.

#136

Hi Brian, I use the 55 gallon drum (about 200 liters) almost every other day to make charcoal. I have larger setups, but they take more time and equipment to operate and my wood pile needs restocked. Winter is also coming and the cold temps are not conducive to making charcoal in the two barrel TLUD method. Here is a link to an article I put together on making charcoal http://driveonwood.com/content/charcoal-made-easy-way
As to what size wood I use with this method, the answer varies. My preffered wood is one to three inches in diameter, three feet long and straight. I tip up one edge of the barrel with a brick and start loading the long pieces of wood, trying to get the barrel well filled. Take out the brick, get a fire of chips and small wood going on top of the charwood and put on the after burner. Should quite smoking within ten minutes. I check it an hour and a half later and then every half hour after that.
You can also use smaller chunks of wood and just throw them in the barrel, but again, try to reduce the gaps between pieces. Keep the pieces to a size that is no more than 3 inches through. Much thicker than that and it takes too long for the heat to penetrate and char the wood. Soft wood is no problem. My neighbor is taking down some Norway spruce (love that tree) and I will be hauling all the branches away, cutting them into three foot pieces and letting them dry. Any branch less than one inch will be chipped for mulch in the garden. Grab that wood, especially if it is handy and free!
Gary in PA

#137

Thanks for the reply… the figure of 3 inches was the one I was looking for- the only other figure that I want to know is how long it’ll take to dry the 3" chunks in UK temperatures and humidities. Gotta ring some blacksmiths…

#138

Hi Garry,

No, the Hydrocarbons are a different story, not to mix up with Hydrogen pure.

The hydrogen comes from the water spray reacting in the hot coal zone.
In my tests i did find out that the less air i give at the nozzle, the richer the gas becomes ( less Co2) , and less Hydrogen from the water spray reacts with Co2 into methane and water.

Long story short version…

Try to work with small nozzle ( 0.6 size of the carb ) and try to use ceramic tips., the mild steel will melt away nearly at any glowing temperature…

Weather you use or prefer to ad water, for some people it is a benefit to have the hydrogen , for others its an eat your engine away if the gas is not proper filtered for acids formed by the hydrogen.

#139

Some interesting points- how are you analysing your gas? There’s still a lot of tweaking and experimenting to do, but the priority at the moment is to build a test/demonstration rig that can be online and boiling a kettle in 10-15 minutes- after that, let the tweaking begin. The variables are: what cocktail goes down the tuyere? Ideally only carbon, hydrogen, oxygen, and unavoidable nitrogen. How hot should it be in the combustion zone? In my current thinking, and I’m open to persuasion, hot enough to ensure that the only compound that leaves the zone is carbon monoxide, but cool enough to get away with a scaffolding pipe tuyere, and occasionally trimming the end off. And manipulating the reduction zone to maximise the good stuff (CO, hydrogen, and tame hydrocarbons), and minimize the inert and bad stuff ( CO2, nitrogen, tars which shouldn’t be in the reduction zone in the first place, and acids.) My current thinking? Cool the charcoal, not the exit gas, so that the gas leaves the charcoal bed cool enough to stop the Boudouard reaction. I might have started lucky with tall, thin fire extinguishers. And catalysts. Currently I’m not bothering to remove the iron catalyst/pallet nails in the char. Do I mix in a load of metal cuttings, or get a big magnet? To be debated…

#140

Hi Brian,

Analyzing trough the hapenings in the plexi bowl above the gasifier i work with.
Second, a lot of study work, then a lot of testing and more experience.

I preffer the short version :wink:

Wet in the plexi bowl means Co2 reacting with hydrogen to methane… sabatier reaction, the temp rises in the upper part of the reactor. Engine mixture needs adjustment,… and a lot more little things…

You need the boudouard reaction to convert the Co2 into Co, see my other posts for the equitations.

The better the quality of charcoal, the less hydrocarbons.both ways the benefits and the adjustments needed are absoleet.

A nice article can be found on wikipedia, look for water gas, or carburated water gas.

A simple tool for checking your gasifier, is a vacuum meter in the section from the inlet tuyere , meaning in the reactor. Having a little vacuum when engine is running is ideal, 100 mbar is ok

The temperature range working in is a point of debate. I sugest to try both and learn the pro’s and the con’s…
Just remember what you need as product and what your input material is.
To convert carbon from charcoal into carbon monoxide you need heat…

Watergas is very rich on hydrogen and carbon monoxide…
Working range between 1000 and 1200 degree celcius is the old fassion way…
At 1200 degree steam is replacing the air… decreasing the temp.
From 1000 degree steam is replaced again with air to increase the temp again
This keeps working in an alternating way …
And produces the highest levels of hydrogen and carbon monoxide.

Other working systems, since nearly 100 years, is a water drip at the intake nozzle or even the pedrick gasifier.
Worth looking into it.

All depends what you want to have at the end…

Charcoal its simple fire :wink: