Charcoal retort woes

[smiles]

Well,fired up newly cobbled together charcoal retort today - and the results were not exactly stunning.

I've made a small bucket-in a-bucket one up a while ago and it worked fine,so have now tried to scale it up by mounting two oil drums inside a steel oil tank (been using drums for a while and want to improve yield/efficiency - so thought that aretort was the way to go)

 

How ever when I fired it up it never really got going,had loads of heat around it and it started gassing a couple of times,but didn't sustain the gassing for more than 5-10 minutes.

 

The drums are full of short lengths of seasoned birch and hazel - I couldn't shut the outer doors as this seemed to kill the fire - so am thinking the flue needs to be bigger to allow the exhaust out and the manifolds from the drums may have too many holes in,two 7mm holes every 75 mm,about 24 in each manifold,maybe too many to allow the pressure to build?

 

Any thoughts anyone?

 

Cheers

Steve

[Chris Sheppard]

That looks great Steve

 

Got any pics of the manifold set up? When it was gassing, did it really roar? my experiences are fairly limited, but on the whole I found less holes worked better, especially fairly mall ones as you could almost get the gas to light in little jets.

 

I reckon to hold the heat in better, if you were setting it somewhere semi permanent it could work well if it was set into an earth bank to act as insulation.

 

I do still want to build something like what you've done eventually.

[smiles]

Cheers Chris,was pleased with the theory,just a bit dissapointed with the test run!

I haven't got any pics of the manifold,too hot today - will try and take some tomorrow -makes sense about smaller jet holes,may need to fill some in as well

 

I really wanted the unit to be trailer mounted so that i can take it to felling sites to process the odds n' sods that aren't big enough to go for firewood,double the value out of the day sort of thing,but I think that Rockwool is going to be the way for insulation once the process is sorted!

 

Post some more pics up tomorrow,all being well.

 

Cheers

Steve

[smiles]

Managed to scrape a meagre four bags out in the end,but 80% were brown ends.

Pics of manifolds attached - any input is more than welcome!

 

Cheers

Steve

[renewablejohn]

Have a look at this retort. It is supposed to be economic on fuel with the insulation helping to convert all the timber to charcoal.

 

[ame=http://www.youtube.com/watch?v=fBYaP5K0AkE]The best charcoal retort kiln in the world? - YouTube[/ame]

 

I have also seen a double barrel version with the second barrel above the first with double the output for the same fuel use.

Edited April 29, 2013 by renewablejohn

[Chris Sheppard]

I can't say with any sort of certainty, but my gut feeling is the gasses can escape too easily and not really getting going.

 

Was there any pattern within the drum of where the brown ends were more brown/less charred?

 

Maybe an increase in the size of the vents as well as the flue might help. Does it have a flue for each drum or just the one in the back right hand corner (if that's what can see in the pic?).

 

 

 

It does look a really nicely made set up, hopefully a few little tweaks and you'll be sorted

[Farmer Tom]

Really impressed by that build quality.

Hope it just needs a few tweaks.

 

How do you seal the drum tops?

[smiles]

Thanks John, i had seen that one,but had discounted it on the loss of volume from the central flue - but looks like the insulation is going to be key,just wanted to test the theory out before investing in insulation,but looks like I might have to bite the bullet on that one! was the double barrel just piggy backed on top?

 

Think your gut feel is the same as mine Chris,next plan is to block half the holes and reduce the hole size on the remaining ones.

 

The brown ends were thoughout the drum,but the best conversion was generally at the top of the drum and close to the drum skin.

 

Just the one flue,being lazy on that one,it's the old oil filler hole which is six inch with a length of seven inch liner screwed on - but it didn't seem to be shifting much smoke,thinking that two smaller liners may be better,get hot and draw better directly over each drum!

[smiles]

Thanks Farmer Tom,feeling a bit more upbeat today!

 

Just used the clamps to seal the drum,but there was the odd gust of gas escaping from there,instead of the intended route! so may seal it with a dob of clay or something.

[slack ma girdle]

At a guess if you ave lots of brown ends it is one of two reasons:

The fire underneath did not get hot enough, or

you did not burn it for long enough, or

both of the above.

Good luck