Ideas

[DMc]

https://www.researchgate.net/publication/237079642_Biochar_effects_on_soil_biota_-_A_review

Paul, it might help you in determining your design if you predetermined your target pyrolysis temperature.
Feed stock and processing methods will produce widely different products. There are many papers available on this. I used this one as an example merely for its simplicity and the use of oak in the feed stock.

 

[Marc-Antoine]

For me, the refractory cement (or bricks) has only one purpose : sustaining the direct contact of the high heat and eventually the fire blast from a oil or gas burner without cracking and crumbling like the usual one. But I don't see it as a real insulator to keep the energy inside the oven. Rockwool or ceramic fibers should be far better for that.
In all cases, you have to avoid any direct hit because of the fragility of this layer.

What is a killer is the thermal expansion which creates huge stress, inside the parts and between parts. The design has to be carefully studied to not create some weak points.

 

[treetx]

This guy seems to have built a nice mobile unit.

http://www.energyfarmers.com.au/building-biochar-kiln/

 

[cory]

Wow those guys are on it. High goals indeed.

 

[Thor's Hammer]

Paul, if you want to learn about pyrolysis and wood gasification, you need to read all doug williams / fluidyne stuff. Be aware that a LOT of money has been sunk into this stuff, probably in the hundreds of millions, with varying degrees of success. You won't do this successfully on the cheap.
http://www.fluidynenz.250x.com/

There is a good reason the price tag is expensive on this stuff.

 

[flushcut]

Burnham, as with every product I have built it comes from the simple reason that I need one. Nobody to my knowledge builds an incinerator that produces biochar as a by product. Shit the air curtain incinerators that are sold currently cost $140K !! and just burn wood. I want to develop an affordable system that others can reproduce that can both benefit them and the envoirment by disposing of copious amounts of wood waste and producing char.

I want an affordable wood splitter that a worker can just load a block of wood into up to the size of say 36" and it will be split with no other input from said worker. Yes there are many wood splitters out there but none that meet my needs or budget.

With regard to the incinerator I have taken possession of a 40 yard roll-off box and a 100 HP fan. I am still trying to come up with a cost effective way to insulate the box that will hold up to the abuse, something like refractory cement.

Anyone??

I have seen full blown firewood processors that can split a 36" round into 16 or more splits in one shot. Take the automated saw and log deck out of it and you have your splitter. I think your budget is going to be the biggest factor.

 

[PCTREE]

Budget is the biggest factor with both of these projects. Shoot it cost me $70k to get the Wraptor to market (admittedly because I was a moron). I won't be able to make too many frig ups with these.

Ed you are basically saying Im Fooked right? Remember Im not in any way concerned with reaping hardly any energy out of this system just produce some char .

My machinest suggested putting I beams vertically and a skin of 321 stainless with the void filled with perlite. DAMN that 321 is expensive

 

[Tree09]

Forget the ss, 321 is ungodly expensive and is used in chemical plants for corrosion resistance at high temps, but only up to 1500 f or so. You will be wayyyyyyy past that, so you will just get precipitation hardening and cracking, at which point it is non repairable because the chrome is gone. Power plants use chrome moly for their steam lines, but those are cooled constantly by the flow of steam, same problem as before the way you want to run it. Your sides facing the fire so to speak are made of refractory, and provisions are made to handle abrasion. I guess the question is what do you want to do with the material? You mentioned that you want this to be portable and quick like a chipper, but that would release so much heat that most locations would not work. You also say that you don't want to use the energy, just make biochar, but that is unrealistic because there is an absolute shitload of energy there, which is worth way more than the charcoal.

 

[Tree09]

I have a few of a huge boiler for a college campus i was involved with a few years ago. You can actually see the firebrick and refractory lining, as well as it lighting up on diesel (backup fuel source). 2 of these boilers heats the entire campus, hot water and cooking included, as well as autoclaves, dryers, etc. Ran originally on gasified coal, now natural gas with oil backup. Absolutely amazing power, each one is 1 million pounds of steam per hour, or just under 29,000 boiler hp. And these are tiny compared to power plant boilers, which have superheaters to dump even more energy into the steam before the turbines. When this particular job was going the engineer had stated that it was going to cost 1 million more a year to run on natural gas vs the coal they were using to give an idea of the amount of fuel needed to run one of these.




The first pic is showing a cast iron part that shapes the incoming air, and the second pic is showing the boiler first lighting up on diesel before we got the settings right. When it's running correctly, the flame is just blue, any yellow shows incomplete combustion.

 

[Levi]

Whoa!

 

[kevin bingham]

whoa is right. I agree that it seems that finding a use for all that heat other than making charcoal would make sense

 

[flushcut]

Tree09 good to have you at The House! It is truly amazing the mixed bag of people here.

 

[pantheraba]

We have amazons, too??? Cool.

 

[Tree09]

Thx, Im just happy to be part of this awesome forum

 

[MasterBlaster]

 

[PCTREE]

Tree09 thanks for the input. Talked to a blacksmith today and he said under those conditions no metal would hold up well,,,, UNLESS there was water behind it to cool it.

So now Im going to put my roll-off in a swimming pool and fire that bitch up !!

 

[Tree09]

Lol that would be fun Paul, but unfortunately that's not even the answer. This is gonna be a long post, sorry. Heres a pic of me earlier today attempting to weld 316 ss pipes that are used to heat a cleaning step in a paint facility. I would weld the cracks or holes, but then after 30 mins or so, the pipe would crack outside of the repair area in a previously non leaking area as the stresses from welding literally pulled the burnt steel apart. Called chasing cracks, it's a rather frustrating way to spend a day lol. In boilers, heat exchangers, etc the thermal cycling and rapid cooling stresses the metal and changes the grain structure. This is the same reason you cannot cool off welds with water, because the grain of steel is frozen in the brittle (but hard) form. In real life, boilers like the one i showed pictures of, powerhouses, etc are retubed, as in they cut all of the tubes that are exposed to heat out and install new ones on a regular basis.


Now back to what you are trying to achieve. You want to make biochar, using waste wood. You don't want to handle the material to achieve complete uniformity, and you want it to more or less not give you headaches in maintenence. Enter the stratified downdraft gasifier. It has no restrictions on size, so material that bridges (woodchips, logs, etc) is less likely to jam up causing hotspots. Made from firebrick, castable refractory, or even mild steel that is replaced every so often, it's easy to build. Some material always kinda clings to the sides, so it's even sort of acts as the insulator, further reducing wear. The chips can't be wet or frozen, but green chips are fine as the moisture is actually broken apart atomically and turned into more producer gas. So you pipe that to anything you would hook up to natural gas, including but not limited to boilers, burners, even motors such as a generator. The input can be automatically controlled, as would be the ash, or as you prefer biochar. You can get more biochar by augering out faster, before it completely converts to ash. You can get less biochar and more gas by changing the speed to allow all of the hydrocarbons to burn off. You clean the gas by cyclone filters, and cool it to increase its density. In a nutshell, that is a greatly simplified explanation of a gasifier, and how charcoal is made.

 

[SeanKroll]

I was concernedfor a minute that your illustrations we going to out the Buck Rogers design, but there it is. ��

 

[MasterBlaster]

Geeze, Kyle...

Rawk on wid your bad self!

 

[Tree09]

And because i feel the need to detail this again, here's some pics of me prepping xray weld repairs on rope axcess. lol. 6" sch 80, tig root stick out, had to do some of them with a mirror.

 

[MasterBlaster]

Hahahahaaa.

Damn straight.

 

[FireFighterZero]

Nice.

I always thought stainless could be rapid cooled?

 

[Tree09]

Well played sir, some forms can. However when attempting to repair cyclical heated ss, the problem exists why did it crack in the first place. Sometimes it's just corrosion, but when is used in heating applications it's usually from expanding and contracting in service, which work hardens it, and changes the properties. The 300 series is considered austenitic stainless steel, which means austenite is the primary phase. However if it is overheated (especially by welding too hot), the chrome burns out, changing the chemical makeup which means it's no longer 3xx. Its usually the heat affected zone that cracks, because that is where fastest cooling happens, and sets up the ares for further stress in service. When we teach our apprentices, if they can tig weld fast enough to just turn it straw colored with a slight tinge of blue, they are getting dialed in. Biggest flaw is turning your heat down and going too slow, thus putting too much heat on it. Hot and fast, just how we like it lol

 

[BlackSmith]

LU 353?

 

[woodworkingboy]

Isn't that what pulse welding is designed for, keeping heat to a minimum? You can dial in the length and type of pulse to best suit your specific task and material.