Upon checking the contents of the retort my suspicion proved justified. The wood contained therein was merely pyrolysised, and barely charred. This is my fault, for a few reasons. Firstly, I attempted the burn in an open barrel. Secondly, I didn’t continue to tend the fire for nearly long enough once the inner barrel had ceased venting steam. I added a vent stack to the lid and am going to attempt another burn as soon as weather and scheduling allow.
3 Likes
Marshall, Thanks so much for sharing your results. It helps all of us learn.
I would have said, “merely torrified,” because I assumed pyrolysis meant that the wood had become charcoal. It appears that pyrolysis includes torrefaction. Anyway, I found a good explanation of pyrolysis and posted it under the Charcoal Making Anecdotes topic.
4 Likes
Thank-you for the clarification, Bruce. Been trying to absorb a lot of new concepts, so I’m not surprised I bungled the vocabulary.
I other news, I’m going for round two this morning. I added a few feet of flue, and of course that made a world of difference in terms of natural draft. Going to spend the day organizing the shop and hopefully doing some assembly and pressure testing on the pile of hardware I hope to make a gasifier out of.
4 Likes
Last Saturday’s burn was similarly unsatisfactory. Being so concerned about draft, in addition to being in a rush, I didn’t adequately pack the space between the barrels with fuel, and so I failed to reach and sustain adequate temperature for the wood gasses to take over. I performed another burn on Friday that I was able to check on just now, and as they say the third time’s the charm.
I’m sure you’ll notice those brands, as I certainly did. However, when I cracked them open to take a closer look they appeared to be charred all the way through, with only light branding on the surface, which struck me as odd.
In any case: progress, albeit at a slower pace than I’d like.
8 Likes
Hi Marshall , yeah i have had some wood that when cooked has a brown tint to it but fully carbonized through out only seems to happen once in a while , and never had a gummed up engine from it .
I’m not a fan of the barrel within a barrel method for making engine grade charcoal , but if it is easy for you then carry on , only first do just 1 thing that will make a huge difference to your charcoal quality and speed , get hold of some old insulation if you can ,any old stuff will work if it saves you buying new , and wrap that around the outside barrel and on top of the lid , that will save a huge amount of heat radiating out and away from your wood and direct it more towards the center barrel .
Dave
5 Likes
Ha! Ha! Yes. Yes. One of the core consepts of James Hookways system.
And my nest new custom Tee-Shirt once Covid settles and we can establish a new normal:
“Let NO BTU’s Escape UnWorked!!”
Or, old metric, you’d say CALORIES instead of BTU’s.
New SI would be joules. Somehow just not the right ring to that though. You’d spend too much time explaining these J’s, although system valuable, are not bright and sparkly.
Steve unruh
2 Likes
So, I haven’t posted in a few weeks, but not for lack of time spent in the garage.
Had a few false starts and setbacks with the fuel/air intake manifold heading into the engine block. At first I couldn’t decide whether to bypass the carburetor, and then I was met with setbacks regarding the MIG machine I was trying to use (no closeups on that part for a reason).
Going to be testing for leaks and building a grading sieve today. Maybe I’ll try out a test fire if it’s a productive day, no leaks are found, and I can find a piece of wool for a filter. Not going to rush it, though, as that’s when I tend to make the most mistakes.
12 Likes
Hi Marshall,
Your work looks really clean. I noticed the pipe and valve on the nozzle port. Are you planning to recirculate exhaust gas?
Rindert
2 Likes
Thank-you for the kind words, Rindert. I try to keep things looking tidy, but I’m still a bit unhappy with the lack of rigidity, what with all of the plastic and the flex hose. I’ll probably end up adding some stay wires so things don’t flop about too much when I wheel it around the garage. Also, it isn’t very modular. I wanted to use couplings on the hoses so things could be disassembled and serviced more easily, but I recall reading elsewhere on this forum that some folks had a hard time with vacuum leaks at couplings.
Yes, I do plan on recirculating the exhaust eventually (and perhaps play around with a water drip as well). I still need to attach a hose to the generator exhaust, but aside from that the unit is more or less ready to go. I just finished up the frames for the sieves, and am in the middle of trying to find the staple gun so I can get the hardware cloth put in place.
2 Likes
Due to work and family constraints, I have not yet had time to do a test-fire of the system. More specifically, I have not had time to prepare an adequate amount of charcoal to perform a test-fire. I was able to spend a few hours chopping up and sorting char last Sunday, but after a few hours I didn’t even have enough to fill a paper grocery bag and my respirator filters were shot. That said, I’ve enlisted a buddy to help me crush and sieve tomorrow morning, and I picked up a few cans of flex seal in anticipation of finding leaks.
I am now firmly of the opinion that a charcoal grinder is a necesarry addition to my setup, and ordered a pile of parts last night for the purpose of building one inspired by Gary’s design.
3 Likes
Amen. Even the crappy little hand cranked one I made will grind a five gallon pail of char in a couple of minutes.
3 Likes
I cant see your flex pipe very well. If it is what I think it is you can not use it: it is not air tight.
Other than that that is beautiful looking machine.
2 Likes
Keep your eyes out for yard sales or kerb sides for junked out old wood mulchers they make the best charcoal crushers , i got one and put a motor from a old wheel chair that runs off 12/24 volt dc , and it makes the best pop corn sized charcoal with very little dust if you gear it down .
6 Likes
Marshall,
I’m also not sure what type of flex pipe you are using. I use flex exhaust pipe similar to what Gary Gilmore has used on his Simple Fires. i’m not sure how tight it is, but it has worked fine for me. Mine may be galvanized, but I know it is not stainless. Stainless, if available, would be better for sure.
2 Likes
Matt,
I’m using 1-1/4" inch exhaust hose similar to what was used by Gary and several other builders I’ve seen on this site. For what it’s worth, I share your reservations as to how air-tight the hose will be, and suspect that if any leaks occur it will be due to that. If that ends up the case, I’ve got several cans of flex-seal on standby. I’m hoping it’s not a widespread issue, however, as the whole idea behind using the exhaust hose as opposed to rubber tubing was for it to act as a heat sink, and I feel that coating all of the hose with rubber would sorta defeat the purpose. Also, thank-you for the compliment. It’s encouraging to hear knowing the quality of work you put out.
2 Likes
Steve,
The hose has a galvanized finish. I’m hoping that there are no leaks so I don’t have to coat the hoses, but if need be I can always rubberize them. Unfortunately, I was laid off earlier this year when I began purchasing supplies for the project, otherwise I would have preferred to use a lot more stainless. As of right now the gasifier vessel and my charcoal retort are both carbon steel, and I know that retort is going to need to be replaced fairly regularly until I bite the bullet and spring for stainless.
2 Likes
Hey, I actually have something like that Dave. Been sitting for about 18 years because it wouldn’t grind branches the size they advertised so useless for that. I’m going to have to dig that out.
I keep several cans of flex seal handy as well. However when in doubt I break out the gorilla tape. I’ve seen that RedGreen show on TV. I know you can fix anything with duct tape.
3 Likes
You do not to need stainless steel and its not a a good material for this. There is no oxygen in the gasifier it is impossible to oxidize the metals. SS retains heat and this is the opposite of what you want for cooling the gas and SS retains heat very well. In a heat chamber this heat absorption will lead to expansion that SS also does very well. Apply a slight amount of heat to it and it will distort and warp quick. That distortion and expansion will lead to stress hardening and then cracking. I know quite a few machines that were commercially available that have failed due to this. SS only makes it look pretty and nothing else. Maybe the hopper on a raw fueler but for charcoal you will be fine. Clean the acids out if you store it and it will be fine.
If that flex is not coated sealed it will leak and be a problem.
3 Likes
For gas cooling use aluminized pipe. This is what it was developed for.
The only failure I have ever seen on any machine Ive ever produced was a cyclone. This is due to this being right after the gasifier as it is the point at which the gas will start to hit due points but also is a point of large dust accumulation. Combine the two = wet acidic goo > rotting out when sitting over time. So besides them being a royal PITA this was the other reason I scrapped them at the reactor. I did later use simple versions for moisture dropping but have also scrapped that as well. I now use simple pancake filter and those things are working very well.
This is a dual plane, we can stack them indefinitely. You can also fill in-between the planes with additional media. Put it as close as you can to the engine, I think the engine pulse is also doing something to create high pressure frequency in relation to the filter felt that make up the planes. Only theory and only just starting with this design but so far it is the best filter system I have developed.
4 Likes
