Charcoal Kilns - what to buy?

[SteveA]

Probably a tricky question to answer and I'm not sure how a reliable test could be carried out:

 

According to various charcoal making techniques; is there a direct corellation between input/ output ratios and emissions?

 

I've been assuming an insulated retort would produce far less emissions than traditional fire pit methods & ring kilns.

 

Cheers, steve

[jaymo]

Jaymo, can I ask how much you're kilns were? Presume these are quite pricey.

 

Hi the standard 2 cylinder retort starts around £18,000-19,000 I believe. We made some alterations to the design... Thicker steel in places, higher profile to aid with unloading, larger cylinder, larger firebox etc so the price goes up accordingly. There are cheaper models like the single cylinder retort. It's worth a look on the 'four seasons fuels' website.

[the village idiot]

Probably a tricky question to answer and I'm not sure how a reliable test could be carried out:

 

According to various charcoal making techniques; is there a direct corellation between input/ output ratios and emissions?

 

I've been assuming an insulated retort would produce far less emissions than traditional fire pit methods & ring kilns.

 

Cheers, steve

 

Not sure I understand the question Steve, but I'll give you an answer anyway:biggrin:

 

Traditional ring kilns are reckoned to have an input to output ratio of around 7:1. My exeter retort is thought to have a ratio of around 4:1. It is hugely dependent on the moisture content of the wood, unfortunately I have never weighed the charge wood so can't give my opinion on this.

In terms of volume, if I stack the charge chamber (1.7 cbmtrs) with hazel in the round, I reliably get about 0.9 cbmtrs of charcoal out. Giving a volume ratio of around 2:1.

From memory there was never a day when I opened the ring kiln to find it 50-60% full of premium charcoal like I get with the retort.

 

As you suggest, an insulated retort is certain to be dramatically more efficient in terms of heat retention and, due to the burning off of the wood gas, will be massively less polluting.

Some people believe that charcoal burning in ring kilns and pits may well be outlawed before too much longer.

[richy_B]

Thanks. If you have the sales it's worth investing on the right kit.

 

If you are going to do charcoal and make a living you need the volumes you mention. Our Exeter retort can produce a 100kg a day so has to be something you run along side another activity. Standalone you'll never make any money.

[the village idiot]

Thanks. If you have the sales it's worth investing on the right kit.

 

If you are going to do charcoal and make a living you need the volumes you mention. Our Exeter retort can produce a 100kg a day so has to be something you run along side another activity. Standalone you'll never make any money.

 

Agreed.

 

However, the tree hugging hippy in me is tempted to say that if our governing bodies and society in general were more sympathetic towards people looking for a simple, low impact existence, charcoal production would transform from a labour of love for the deranged into a nice little earner, with huge benefits for our woodlands and the global environment. End of ridiculously long sentence!

[richy_B]

You'll be waiting a long time for that to happen! 99% vote with their wallets.

[jaymo]

Thanks. If you have the sales it's worth investing on the right kit.

 

If you are going to do charcoal and make a living you need the volumes you mention. Our Exeter retort can produce a 100kg a day so has to be something you run along side another activity. Standalone you'll never make any money.

 

I suppose you are utilising a product that would have originally gone to waste. That is all we are doing (kind of) but on a larger scale. Originally the estate set up the charcoal buisness after the 89 hurricane (long before I started) after that all the smaller diameter wood that was once pushed up and burn now had a new use.

Now we produce cord wood for firewood, 6-7 inches and above and anything less will go into the charcoal production. We also have the advantage of our 1500 acres on the doorstep, production cost have to be kept to a minimum so as to make any sort of profit on this scale so everything is sourced from here within 2 miles or so.

It helps with having such a large amount of Woodland the forestry team can be selective over what they cut and when they cut it, ideal to ensure the best mix of wood is been used to produce charcoal. All of this really does go in our favour.

[the village idiot]

You'll be waiting a long time for that to happen! 99% vote with their wallets.

 

Do they really!

 

Presumably they are all returned once the vote's been counted?

[the village idiot]

I suppose you are utilising a product that would have originally gone to waste. That is all we are doing (kind of) but on a larger scale. Originally the estate set up the charcoal buisness after the 89 hurricane (long before I started) after that all the smaller diameter wood that was once pushed up and burn now had a new use.

Now we produce cord wood for firewood, 6-7 inches and above and anything less will go into the charcoal production. We also have the advantage of our 1500 acres on the doorstep, production cost have to be kept to a minimum so as to make any sort of profit on this scale so everything is sourced from here within 2 miles or so.

It helps with having such a large amount of Woodland the forestry team can be selective over what they cut and when they cut it, ideal to ensure the best mix of wood is been used to produce charcoal. All of this really does go in our favour.

 

Hi jaymo,

 

Are you Tregothnan? I would love to come and see your setup at some point. Do you do visitors? (I will only ever be very small scale, so not a competitor)

[SteveA]

Not sure I understand the question Steve, but I'll give you an answer anyway:biggrin:

 

Traditional ring kilns are reckoned to have an input to output ratio of around 7:1. My exeter retort is thought to have a ratio of around 4:1. It is hugely dependent on the moisture content of the wood, unfortunately I have never weighed the charge wood so can't give my opinion on this.

In terms of volume, if I stack the charge chamber (1.7 cbmtrs) with hazel in the round, I reliably get about 0.9 cbmtrs of charcoal out. Giving a volume ratio of around 2:1.

From memory there was never a day when I opened the ring kiln to find it 50-60% full of premium charcoal like I get with the retort.

 

As you suggest, an insulated retort is certain to be dramatically more efficient in terms of heat retention and, due to the burning off of the wood gas, will be massively less polluting.

Some people believe that charcoal burning in ring kilns and pits may well be outlawed before too much longer.

 

Cor blimey guv, I dint know Hazel could return at 2:1 ....we have a few acres of unmanaged Hazel coppice (overstood) that needs a lot of stool hacking so turning it into charcoal/ biochar at 2:1 sounds like a super dooper option.

 

You kind of nearly answered my question.... what I'm saying is.... eg; would a Hazel burn at 2:1 ratio have 50% less emissions compared with burning a different type of wood at 4:1 ratio.

 

And how are emissions tested on a device that gets so hot and leaky to the outdoor environment?.... especially at the stage where the kiln lid is off/ or retort door is open, or earth clamp smouldering?

 

Another question I have is on embodied energy, and probably much harder to answer:.... Are the emissions from manufacturing & repairing metal retorts as bad/ or worse as burning charcoal in an earthy pit (that uses no metal)?

cheers, steve

Edited May 21, 2016 by SteveA