Mobile Retorts

[TRADITIONAL LOGGERS]

Thanks for the pictures and update.

 

Noticed using a plastic bucket to unload. Do you leave kiln to cool down before opening? Then check charcoal before bagging?

 

We know someone who bagged straight from Circle kiln then drove off with product on truck which refired down the road!!

[the village idiot]

Thanks for the pictures and update.

 

Noticed using a plastic bucket to unload. Do you leave kiln to cool down before opening? Then check charcoal before bagging?

 

We know someone who bagged straight from Circle kiln then drove off with product on truck which refired down the road!!

 

 

Yes, it is imperative to let the Kiln cool down before opening, ideally to ambient temperature. Having said that, even stone cold 'fresh' charcoal can very occasionally spontaneously ignite. For this reason it is advisable to leave it standing for a few days before bagging. This enables it to absorb some atmospheric moisture, making it more stable.

Some impatient charcoal makers have been known to open kilns early and drench the Kiln contents with water. In my view this is not only a risky strategy but must also affect the quality of the end product.

A wood collier has to learn to operate to charcoal time. Sometimes a burn will be unpredictable and will take you long into the night. Some would find this unacceptable, I think that it adds to the romance!

[timbernut]

Have also considered brick Alexander retort as I'm permanently based in a wood with concrete track access. Has anyone seen one working/used one? I know you have to buy the plans but would like to know if they're efficient it would certainly stop the warping problems

 

 

 

I haven't heard of the Alexander retort. There is a brick built retort called the 'Adam Retort' which may be similar. The only people I know to have tried this system in the UK are Carbon Gold. They are the big cheeses in UK biochar, set up by Craig Sams (the ex Green and Blacks owner). Carbon Gold have now developed their own range of retort kilns so presumably didn't get on with the brick retort.

 

It is a popular design in the developing world because it is relatively cheap and can be built by any bricklayer. The potential issues with them, as far as I can see, are similar to those with ring kilns ie. No real temperature control and the need to climb in and shovel out the product. This is unpleasant enough when you have had a good burn but soul destroying when your kiln is full of ash and unconverted wood.

 

Carbon Gold would be the people to ask for an informed opinion.

 

 

Sorry I meant Adam (not the first time I've mixed the name up) had wondered if you could design one that you unload from the side

[timbernut]

I know only too well the joy of unloading a crappy burn : ) it's not the smallest reason for heading 'retortwards'!

[hedgesparrow]

i read aout the adam retort and looked a pain to use having to get in to dig the charcoal out its a dirty game without getting covered. looked at a double retort esele or like that then saw price £21k need to be making a lot to get any payback. yes 300kg per burn but a big investment. not aimed at the coppicer who wants to make some charcoal from the waste product

[openspaceman]

i read aout the adam retort and looked a pain to use having to get in to dig the charcoal out its a dirty game without getting covered. looked at a double retort esele or like that then saw price £21k need to be making a lot to get any payback. yes 300kg per burn but a big investment. not aimed at the coppicer who wants to make some charcoal from the waste product

 

Chris Adam's retort was aimed mainly at the third world. Because his starategy is to license the drawings for a fee I have never seen it in detail but did think it depended on a metal plate for heat transfer.

 

In January Chris announced a mobile model based on two 205 litre (45gallon) barrels.

 

I wonder if he has copied and scaled down Yury's ekolon model, this uses several cylinders filled whilst upright and then inverted over a common manifold, the idea being to run them sequentially to avoid needing any support fuel.

 

I have tried this successfully with one barrel in a burner and on a much smaller scale charred some seaweed this way for a growing trial.

 

It has a number of merits in that the barrels are cheap and with a suitable alternative flame path (perhaps automated with the use of a flap controlled by a bimetal strip) the barrels could be kept at around 600C outside which should increase their life.

[openspaceman]

Yes, it is imperative to let the Kiln cool down before opening, ideally to ambient temperature. Having said that, even stone cold 'fresh' charcoal can very occasionally spontaneously ignite. For this reason it is advisable to leave it standing for a few days before bagging. This enables it to absorb some atmospheric moisture, making it more stable.

 

Yes and it's probably best to spread it out a bit. The reason being nascent char is hygroscopic, it absorbs water from its surroundings, and when water changes from it's vapour state to its liquid or solid state it give up energy. This is exactly opposite to drying where in order for the water to leave wood some energy has to be supplied to turn the water to vapour.

 

This vapour has to give the energy of vaporisation as heat and the result is that if the pile is deep it is insulated from the surroundings and the temperature goes up, fresh char will auto-ignite at about 200C.

 

Similarly being black char is a good absorber of radiant heat and it can absorb enough heat from the flames of a nearby fire to ignite.

[MartinN]

Revisiting this thread.

 

How are the Exeter retort users getting on with them.

 

I noticed that Sainsburys are selling the Bio-Regional charcoal at £16 a bag (3kg I think)

 

Do you think this is a realistic price? Or is it inflated to give discounted price later.

 

I keep thinking of getting into production, apart from lack of wood and where to do it and keep checking out viability.

 

I think £16 is over the top especially when put against a £4 bag supposedly for the same stuff. Can all you charcoal burners out there get £10 a bag.

[timbernut]

It's what it should go for but rarely does, there's only so far over the imported stuffs price you can go before the retail customer says I wanna buy ethical/local but that's just too much! I sell by volume not weight partly because I use mostly s/woods now sell small (same size as Selway packaging ones 3 kg i if h/wood)4.50 wholesale and double the size clear plastic ones for 8. over gate 6 and 11 respectively. I get by😀

[the village idiot]

Revisiting this thread.

 

How are the Exeter retort users getting on with them.

 

I noticed that Sainsburys are selling the Bio-Regional charcoal at £16 a bag (3kg I think)

 

Do you think this is a realistic price? Or is it inflated to give discounted price later.

 

I keep thinking of getting into production, apart from lack of wood and where to do it and keep checking out viability.

 

I think £16 is over the top especially when put against a £4 bag supposedly for the same stuff. Can all you charcoal burners out there get £10 a bag.

 

At £16 for 3kg someone is laughing, and it won't be the maker, the one who actually does all the work!

 

I believe Bioregional were bought out by Rectella (the big boys) a while back. Bioregional had ethics but still couldn't pay the producers very much so I very much doubt whether Rectella (non ethical) are doing any better. Does anyone know what 'bioregional' producers are paid now? I would imagine that the producer is not seeing much more than a pound of the £5.30/kg selling price.

 

Almost all my charcoal goes ungraded in bulk to other wholesalers. I get around £1.20/kg for this.

I would be well advised to push for more but I am a terrible businessman!

 

To retail customers (graded and bagged hardwood) I sell by volume (large selway 'coppice

association' bags) £7.50. They sell on for around £10. I can't remember exactly what these weigh but it is around 4kg. I'll try and put one on the scales later today.