Mobile Retorts

[TGB]

So, anyone have any experience of the the 'Exeter' from The Exeter Biochar Retort - The cleaner and more efficient method of producing biochar and barbeque charcoal. or similar device? What sort of payback timescale would there be?

 

Your opinions please.

[the village idiot]

Hi TGB,

 

I have one of those (exeter retort). I'm just off out but have plenty to say on the subject and can post an essay this evening.

Where are you based? You are welcome to come and see mine or I can put you in touch with another owner.

[jon bown]

ID BE INTRESTED TO IN YOUR COMMENTS JUST ABOUT TO BUILD ONE FROM A BIG 5000 LITER OIL DRUM

MY KILNS ARE OK BUT YOU LOOSE SO MUCH IN THE BURN THOUGHT ID GO RETORT

COULDNT JUSTIFY THE MONEY SO THOUGHT f88K IT ILL MAKE IT

CHEERS

jON

[Marko]

Looking forward to reading about your experiences.

[ballibeg]

That's me subscribed to this topic as well!

 

Dave

[the village idiot]

Hi folks.

Firstly apologies for not posting last night as promised. I had a longer day than planned and fell asleep on the sofa!

 

So to the exeter retort. I bought the second one off the production line in June 2012. I believe there are still only about 10 in existence. This is almost certainly due to their cost compared to ring kilns. My retort cost just shy of £10,000 plus vat. The sellers can also provide a custom built trailer for another £2000, but I opted to fore-go this and bought a cheap but sturdy car transporting trailer off you know where for £200.

The kiln itself weighs in at 1300kg and will hold around 500kg of wood (dependant on species and water content) so any trailer needs to be rated at 2000kg to be safe.

 

The exeter retort produces superb quality charcoal. I have done around 40 burns with mine so far (my main focus is woodland management so am not charcoaling full time) and have not had a single brown end (piece of unconverted wood) or burn out (hugely disappointing kiln full of ash). The retort also seems to produce a relatively small amount of fines compared to ring kilns.

 

Having used ring kilns in my mis-spent youth I can categorically say that in comparison the exeter retort is an absoloute joy to use. It is much faster (burn time from lighting to walking away can be as little as 6 hours). It is a doddle to load and unload, and importantly it is far less damaging environmentally than a ring kiln as it burns off a large proportion of the volatile wood gasses as part of the process.

 

In theory you could do a burn a day with the exeter retort, although in reality this would be seriously hard work and I would say that 3 burns per week would be a more achievable target. The ratio of loaded wood to charcoal product is about 4:1, so with a 500kg 'charge' of wood I get about 125kg of the black stuff. This also compares favourably with a ring kiln which has a ratio of around 7:1.

 

To give you some idea of figures, I sell nearly all my charcoal wholesale (ungraded) so straight out of the kiln and away. Charcoal grading and bagging is a true dark art which I avoid at all costs! I sell for £1.10 kg which equates to about £130 per burn. I could get more for the charcoal but I have found two buyers who I have an excellent relationship with, and I value this much more highly than achieving bigger returns with more hassle. There is another retort owner who converts beech and is knocking on the door of 200kg per burn, but this is hard on the kiln and has its consequences- more on this later.

 

I'm afraid I've run out of time this morning, but before you all rush out and buy one please stay tuned for the next instalment. There are several things to take into account before taking the plunge and I would not be doing you any favours if I didn't take some time to explain these.

 

I'll try and post again within the next couple of days.

 

All the best. TVI

[TGB]

Sounding good so far, price is reasonable. I wonder what the projected life of the kiln is; maybe that'll be touched on in part 2.

[TGB]

This first one, would be based in S.Wales, with a volunteer group. I've got friends, (non woodland) who live just over the border from you in Essex. Might be worth a trip over.

[the village idiot]

Hi folks,

 

Just wrote a monster post on the retort, just before sending my computer crashed and I lost the lot. Doh!!!

 

Am now going to gayly skip amongst the bees, brambles, birches and butterflies to regain my composure.

 

Will try again later, TVI.

[TRADITIONAL LOGGERS]

Interesting post!! Expensive compared to standard kilns £600 and I would be interested in lifespan as would have to work it hard to cover payback. Do the internals buckle and what's the insulation material. What do you unload into to allow cooling before bagging?