Charcoal Gasifier

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Basics

  • There are some advantages with using charcoal (rather than wood) for gasification (section taken from: Troy Martz Gasifier). These may include:
    • Sufficiently drying wood/biomass to an appropriate water content % takes days. Charcoal can be made and used in mere hours.
    • The byproduct of charcoal sizing (anything under 1/16th of an inch) just happens to be perfectly sized for biochar...what a great byproduct to have
    • We don’t have to worry about tar! Thus, filtration in the down line is relegated to ash and dust…easily done.
    • Pure carbon is a perfect catalyst for the reduction process… You never really get 100% there with biomass.
    • We eliminated “pyrolysis” from the problem we’re trying to solve, so the gasifier design becomes infinitely more flexible than the “Imbert” design
    • We can scale gas production with the same system by merely swapping out a single nozzle size – we can go from 2kW to 50kW with the same machine!
    • Yes, charcoal has less BTU’s, but we can also utilize those BTU’s by capturing and using that heat with a smart charcoal retort design
    • Charcoal gasifiers have the potential to produce far more powerful gas flow than biomass gasifiers... Cracking steam is the key.
Troy Martz Gasifier - gasifies charcoal

Videos

Existing DIY/OS Designs

Greenhill Forge (YouTube Channel) 's Design

Design Overview

Notes Taken by User: Eric while (re-)watching the video

  • Made largely of welded together steel
  • Uninsulated (Unlike the current OSE Design which uses a Fire Brick Hearth)
  • It was made using a CNC Plasma Cutter , thus Files exist somewhere
  • Intermittent Fillet Welds were used
  • A Truncated U Shape is made over the Ash Grate to confine the reaction to a narrower space (presumably to follow the zone interacting with the air, almost the inverse of the "Dead Man" in Blast Furnaces )
  • Oversized Inlet and Outlet Pipes (No exact dimensions mentioned)
  • Only a linear (forward and backward) Ash Shaker , will be interesting to see if that will clog up or not
  • Hinged Lid Reinforced with Square Tubing, and has a Gasket + Spring Latch
  • Adhesive Fire Rope mentioned as a Gasket Material
  • 3 Thermocouples "Stabbed In" (After being predrilled) and sealed with RTV Silicone
    • A more robust solution may be warranted for LONG TERM use (ie if/WHEN a probe fails, and needs replaced etc), but for an experimental setup this is fine
  • It then goes to a Cyclonic Filter
  • Neat Gas Flare made using a standard Soup Can and Steel Tubing
    • As per that Landfill Gas paper, probably the Chandelier Type? (Double Check This)
  • Need to check an older video (with their albeit far more novel Charcoal Retort]] , but it seems this design DOES use Screened Charcoal
    • Seems to be a Trommel of Welded Wire Mesh, akin to that used for fencing
  • Exhaust Blower On + a Blowtorch put in the inlet for start
    • 10-30 Second Startup until Self Sustaining Flare Flame
  • Fuel Tank Removed from Engine, Engine Adapted to Drill Engine Starter , Fuel Line Capped Off, Carburetor / Throttle Body/ Fuel Assembly left in place as an easier experimental setup for that, dedicated replacement can be done later down the line
  • A standard T-Fitting and Butterfly Valve (Neat DIY/OS Design using PVC Pipe made) is made for regulating Air-Fuel Mixture
    • Flashback Arrestors / Explosion Proofing, or at least Leak Monitoring may be warranted on this side, has my safety spidey senses tingling a bit
  • An Air Filter Sponge is used, some sort of 3D Printed / CNC Milled adapter to either the standard String Trimmer/Chainsaw Filters, or a larger filter (Could be identical to HVAC and/or Car+Truck etc for Parts Reduction + Making Stockpiles of Spare Parts Inventory more useful etc) would probably be a better end goal solution
  • A Sawdust Air Filter made from a Open Head Plastic Drum (30 Gallon Maybe?) is used AFTER the Blower/Flare Stack, but before the engine
    • CAN work, but leaves one to wonder on Blower Durability, most are air cooled, and as with Vacuum Cleaner Pre-Motor Filters keeping a blower as clean as possible is best practice
      • Frequent Enough Removal + Servicing could PROBABLY suffice, and again this is an experimental setup, not a power plant!, still just documenting thoughts
  • They noted Corrosion in the Heart, possibly due to an Oversized Reduction Zone (Thus syngas flowing by not doing anything, cooling down/condensing + causing corrosion)
  • ALL IN ALL great design!

Thoughts/Ideas On It

  • I'll have to go check out the OSE Design; they look similar in overall form, but may have different internals and whatnot
  • Materials Science nerd me wonders if having it be CO-rich, Hydrogen -lean would be beneficial for Leak Detection + Reducing Hydrogen Embrittlement etc
  • MORE SENSORS
    • Granted Intrinsically Safe / Explosion Proof Concerns there
    • Also, as with many Modern Cars etc, this can lead to an issue of "What would have been "business as usual" before (No sensor, but operating fine), is now a repair need (Sensor Broken/Faulty->Please Troubleshoot)
      • LUCKILY with Design for Repair / Design for Cleaning and all that, it SHOULD be a matter of remove it + put a new sensor from the spare bin in
        • Also how much does each temp probe cost etc 10-40USD maybe, above that it starts getting a bit much
        • Granted all relevant on how giant/important of aa build it will be/how long they last for ("Buy Once, Cry Once. Buy Cheap, Buy Twice " etc)
  • I do think a Fire Brick / Refractory Lining would help. Designing it such that it slides in and is held in by slots, or is Interlocking Bricks would be nice for a Design for Repair / Design for Cleaning perspective (ie don't grab an SDS Drill / turn the whole thing to rubble/scrap metal, just remove the sacrificial layer and resume
    • I still haven't found a Refractory Material i LOVE from an Appropriate Materials perspective, but Firebrick / some rated mortar etc isn't HORRIBLE (again, need to check out the OSE Design)
  • In terms of Charcoal Size, would powder/1cm chunks work well, or no?
    • Thinking More Surface Area = More Gas, granted do larger chunks/pellets help with air flow, anything smaller would be too clogging?
  • A Rotary Airlock or other means to Refill While Running would also be nice
    • A "Knife Gate" and airtight lid may work a la those Wood Chip Boilers
  • Some means to view Fuel Level (Short of it burns X Liters of Charcoal per Hour, thus we should add another bucket in an hour" type Dead Reckoning would be nice )

Internal Links

External Links

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