[Stoves] Retort can inside TLUD gasifiers Re: Fine particles as fuel in TLUDs

Sun Feb 15 18:15:09 CST 2015

Dear Paul and all,

I'd like to share a few more things about our biomass boxes:

- we only put boxes on the side of combustion chamber so it only use heat
transfer sideway, which cant be used fir cooking anyway. This also help
reducing stove out cover temperature a bit.

- if stove burn for 1 hr, it can turn any thing inside the biomass box to
good char with our normal box, 5cm thick: ruce husk, saw dust, leaves,
small stick (1cm diametter),.... even not so dry naterial. Experimental box
of 7-8cm can do fine with dry material but cant handle fresh garden waste.

- we place the gas release holes below sencondary aiy inlet to mix gas- air
better. With 4 hole,1cm dia on top, at peak time,  the box can give the
flame tall enough to touch pot bottom, which is 10-13cm above. Saw dust
that hand pressed inside the box can burn for 20-30min

Regards,

Anh
On Feb 12, 2015 11:53 PM, "Paul Anderson" <psanders at ilstu.edu> wrote:

>  To all,   both Stovers and Biochar makers.
>
> I thank Marc and Jock and Kirk (and probably some others, including Peter
> Hirst with his barrel-size unit, on video) for their efforts with a retort
> can inside of a TLUD gasifier.   (see some messages below).   I mention the
> following topics for consideration.
>
> 1.  Where inside the TLUD is the retort can to be placed?   The retort
> needs heat to it, but the TLUD *heat *INSIDE THE FUEL BED is only at the
> top and then progressing slowly downward with the MPF (Migratory Pyrolytic
> Front), meaning that the bottom of the can does NOT get heated until the
> MPF is getting close.
>
> Therefore, should the retort can be above the fuel level but below the
> entry of secondary air?   Maybe not, because the can and its contents could
> chill the rising gases and hinder their combustion.  But maybe this is not
> so crucial?
>
> Maybe the retort can is only in the upper half(?) of the TLUD fuel?
>
> Or maybe this does not make much difference?
>
> 2.  I like Jock's idea of the outlet holes being upward in the retort
> can.   He reports seeing the small jets of flame.   That means that the
> retort gases are entering into an environment with sufficient secondary air
> for combustion.   This also is then an issue of the placement of the retort.
>
> Please note that instead of outlet holes there could be an outlet Channel
> (pipe, tube, etc) that takes the retort gases to a different place.
> Remember that retort gases come out in a sequence of types that start with
> water vapor, then mixed gases, and finally the pyrolytic gases that are
> combustible.   Retort processes do not occur the same way as TLUD processes.
>
> 3.  Placing the retort canister ABOVE the secondary air entry provides the
> maximum heat to the retort.   Maybe it could be in the "riser" section, or
> up where the cooking pot would otherwise be placed.   This has been done in
> barrel-size units by Doug Clayton and Hugh McLaughlin and is on video.  The
> main problem encountered is the difficulty / danger of handling full
> barrels well above ground level, sometimes full of hot char.
>
> 4.  Of course, issues of char qualities need to be considered.  About
> putting fines (very small) biomass into retorts, it is known that the
> transfer of heat from the edges to the center is HINDERED if the materials
> are too packed together.
>
> Many of us are looking forward to further reports on this topic.
>
> Paul
>
> Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
> Email:  psanders at ilstu.edu
> Skype: paultlud      Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
> On 2/12/2015 6:35 AM, Jock Gill wrote:
>
> Marc,
>
>  I have also done this.  I place feedstock in a smaller can that only has
> a few holes in its lid to allow the pyrolytic gases to escape and burn.  I
> then place this, as you did, in a larger can used as a ND TLUD and surround
> the smaller can with fuel.  This creates a retort within a TLUD.  The TLUD
> will burn some of the charcoal it has made in order to finish the pyrolysis
> in the inner retort can.
>
>  I find, contrary to the given wisdom, that the inner "retort" can be
> placed with in the TLUD with the gas escape holes facing UP.  This allows
> students to see the gas come out and ignite.  If they can see the flames
> created by the gas coming out of the retort it much more powerful
>  educational experience.
>
>  Well done,
>
>  Jock
>
> Jock Gill
> P.O. Box 3
> Peacham,  VT 05862
>
>  Cell: (617) 449-8111
>
>  google.com/+JockGill
>
>  :> Extract CO2 from the atmosphere! <:
>
>  Via iPad
>
> On Feb 12, 2015, at 5:07 AM, Marquitusus <marquitusus at hotmail.com> wrote:
>
>   Hi, in the mids December I consulted the list about my problems with
> almond husks as TLUD's fuel.
> The problem is the smaller particles of this fuel obstruct the primary air
> flow and the pyrolisys stops.
>
>  Kirk suggested me using the "can method": just screening the fuel and
> use the smaller fraction for filling a can that will be put inside the
> reactor, surrounded by the large particles fraction. I recently tried this
> method, and it really worked! You can see pics here:
> http://cuinessolars.jimdo.com/cuines/cuines-gasificadores/
>
>  So, this opens the door for using any size of fuel in a ND-TLUD, from
> rice hulls to saw dust or any other little particles fuel ( I understand
> that in a FD-TLUD is not necessary, because of the forced air draft). Also,
> this method can allow to shorten the size of the chimneys or risers,
> because less draft is necessary.
>
>  The bad news are we need a can (that is exposed to high temps that will
> deteriorate it) and we need to previously screen the fuel, but I think
> these are minor handicaps compared to the benefits it brings
>
>  Marc
>
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