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Hello woodfolk, I am designing a portable charcoal/biochar retort for use by professional woodcolliers. I am pretty sure about the way my design will work, but I am after ideas of what people would want from a retort, such as capacity or the maximum weight of the thing. Most of my experience has been in woodland creation and tree surgery rather than charcoal making. I have used a ring kiln a couple of times but a retort is obviously a little different. My main motivation is environmental. ie. local charcoal, produced as cleanly as possible, from sustainable woodlands and not destroying habitats on the other side of the planet. What do members think of the state of the market for charcoal and biochar? What do you think of the current devices out there? I am open to any thoughts really. Although I've thought the design through pretty thoroughly over the last couple of years, I'm sure there will be some things that I haven't thought of yet.
I've been doing small experiments with air drying, where essentially the sun is heating air and increasing its capacity to absorb moisture, and in free air (i.e. log standing by itself) and seeing oak dry from green to 20% mc wwb in 44 days. So as heat speeds drying up and solar heat has no fuel cost I started looking at small scale solar drying. I found just using cheap corrugated acrylic sheeting I could make a simple greenhouse where in the last 2 days the temperature has stayed above 40C for much of the day in sunshine with relative humidity falling to 24%. This is consistently more than 10C hotter than outside in the sun. RH is about the same because there is free air flowing and out. Last week I was employed dragging tops and stuffing an ancient chipper on a commercial refurbishment where the previous tenants had allowed the Leylandii and mixed broadleaved hedges run away. I noticed a pair of old cycle racks had been removed and set aside. I mentioned the possibilities of these being the beginnings of a solar log drying kiln for the boss's son, who runs a log round with about 40 customers in his college holiday. Boss being a petrolhead was not at all interested. I made an enquiry and they were available for sale (these things new cost about £5k erected) I sent a photo to the son and explained my thinking and he was interested. At this point father and son took over and bought the shelters. Now I'm not sure if they are going to implement the idea but I estimate placed side by side and south facing they will intercept 18kW(t) in sunshine. This is enough theoretically to evaporate nearly 30kg of water an hour if the air circulation is good enough. With the shelters side by side and south facing and a roofed area behind and the back being a curtain side from a lorry he should be able to stock about 20m^3 of split logs in stillages. I think wit a few low powered circulation fans and a differential thermostatic switch only running them when inside temperature is 10C above outside and a humidistat controlling a vent fan he should get good drying. If I am kept in the loop I will update progress.
Hi guys, just thought i'd share something i've been working on, currently only in the planning stage though so please play nicely. I've been doing a bit of reseach into making my own custom castings for table legs, solid bronze similar to the hudson table that beyonce bought for $70,000 (photos of their tables are attached) the basis of my Foundry design is based around the artful bodger's waste oil furnace Home - The Artful Bodger's Home Foundry/ for which i take no credit, the guy's a genius. anyway I was busy adapting the plans of his foundry to suit a much larger scale bronze melt, when the idea suddenly struck me - why not use this same design i'd come up with that could melt 80kg of bronze within an hour - using nothing but waste oil and a small amount of electricity - to dry timber? I figured that my adapted foundry setup could heat a container sized kiln to just about any temperature i want to, with the temperature being controlled by some circuitry essentially reducing the output of the blower, and feeding less oil, this reducing the burn rate and temperature. garages and the like have to pay to get rid of waste oil, and I've noticed as soon as you mention that you're interested in it, they'll force upon you as much as you can possibly hope for. Now without going into the science of it, your average motor oil has 3 times the fuel density of the wood you're currently powering your kiln with, meaning you use a third of the fuel you're currently using, and this Doesnt accunt for the water content in that wood you're burning which would to let's say 50% of the overall mass of that wood, so in essense by burning oil you're saving six times as much timber to then put into the kiln to DRY, which can then be SOLD Now like i said, this is still in it's infancy, i'm just looking for your input and experience as to whether you feel this sort of system would benefit you chaps that currently run a kiln on wood or gas. Thanks for reading!