Hookway retort vs Iwasaki?

[DennisCA]

I was mentioning a charcoal retort in another thread and someone gave me a tip about Hookway retorts, well that lead me to this

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This looks like a hookway retort to me, though he doesn't call it one. However in the beginning he already mentions that he's made a better one based on a japanese design. He says issues with the design in the link above were "overcooked" charcoal from high temperatures, as well as toll on the components due to the same.

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This one the author claims is better, it's certainly larger and it also uses the woodgas to keep making the coal. But supposedly at a lower temperature. Personally it looks like it smokes too much! Going by the text it's like that for several hours... Don't yet have enough info to make a proper assesment... Has anyone had experience with either of these designs? I can't build anything which creates a lot of smoke, hence the hookway retort was looking real interesting, though apparently it's got issues I wasn't aware of, at least according to this guy.

I'm not really after charcoal for smithing but cooking and taking advantage of the fact I am producing enough scrap to make a few batches every year. But still I want the most efficient setup possible within my means. Hence I am going to be very OCD about anything I set my mind to.

[Ohio]

I built a retort based on the Hookway design and wrote it up here. There are other links in this thread that may help you. I haven't used the other method.

My retort (named Burnie) also uses the gases from pyrolysis---as does Hookway's---to continue the charcoal process. Basically, I start a fire in the rocket stove (named Rocket J. Stove) with small lengths of wood. After about an hour, the pyrolysis gases start feeding this fire and I don't have to add fuel for about an hour and a half. I then add small pieces of wood to finish the charcoal process. If you look at the pictures in the linked thread above, you should be able to see how the gases are fed into the rocket stove.

Rocket stoves burn very hot with little smoke and you can use small pieces of dried materials. I also added a 3-foot length of stove pipe to the top where the rocket stove exits to ensure draw and it works great, though it roars fairly loudly. It's a very clean burn with very little smoke.

But there will be smells. Anything on the steel parts (paint, oil, grease, etc.) will burn off and stink. Sealing materials often smell as they heat up. The area around the barrel may get singed and smell, though you can always put the barrel in sand. Just keep cats away or you may heat up sand that gives off a completely different smell you weren't expecting.

When you open the main drum to empty the charcoal, which you do the next day otherwise it can explode, I find the smell from inside overpowering, like being stuffed into a chimney that hasn't been cleaned since Charles Dickens was alive. I wear a respirator that also protects from the dust because charcoal is VERY dusty. I wear dispoable gloves and clothes I throw away because you will not get the dust out of your clothes. This is a messy and not fun process.

Varying the size of the feedstock (the stuff that goes into the main drum) and how long you let it burn affects the end result. I don't use this charcoal for cooking or smoking food, so I'm looking for full cooked charcoal for smithing. You can get less than fully-pyrolized charcoal by using bigger chunks of material or less burn time. For example, I did a cycle with larger hardwood pieces for 3 hours. All of the material is usable, but some is not fully pyrolized. I now do everything for 4 hours before stuffing the rocket stove opening with mineral wool insulation to put out the fire.

You can buy Hookway's design drawings off his website and it may help you visualize how the design works. The key is insulation. I've also found that some smoke is unavoidable. You can lessen it somewhat, but there's always going to be some. I use a clay mix to seal openings because it's cheap and works surprisingly well, and that gives off steam until everything is fully dry.

I think there are also variations of this design that use smaller (5-gallon) drums and amount of feedstock that may work better for you---less smoke, less dust, etc.

Hope this helps.

[DennisCA]

I've been doing my own research and the hookway design does look like the one for me. I like how it uses the pyrolisys gasses to keep itself going. The iwasaki design while simple and easy to build, and generating high quality charcoal, isn't gonna be viable due to the mode of operation releasing plenty fo white smoke (woodgas that the retort instead uses to sustain itself). 

My dad has got this oil burning air heater that's just rusting, been wondering if I could scavenge parts from it for an outer shell and more.

[DennisCA]

Just for fun, I made a fire in our masonry heater and I filled an empty pickles tin with wood cutoffs (mostly pine) and hammered the lid back down so it would shut, but had gaps. Made a fire around it and let it burn. There where flames coming out of the top of the tin as it was burning. So I was capturing those woodgasses and using them to heat my house.

I think I overcooked the tin however, the resulting charcoal (first I ever made btw) is very light, so I think I got rid of too many of the volatiles.

Fun experiment either way, not getting a lot of charcoal this way, but the woodgas is definitely not being wasted. My fireplace has secondary air so it all combusts.

 

 

[Frosty]

Charcoal IS very light, if it's black and light it's good. You seem to have a LITTLE ash so it's maybe slightly over cooked. Not enough to worry about though.

Frosty The Lucky.