[Stoves] Influence of fuel-bed temperatures on CO and condensed matter emissions from packed-bed residential coal combustion

[Paul Anderson]

Crispin,

In one sentence you say:
> The top lit version does not mean an MPF. You can only really get an 
> MPF if it is a packed bed gasifier and virtually no one is doing that.
And then say:
> Bottom lit updraft (BLUD) is common, and TLUD is also common. MPF is 
> not going to be seen, not a real one. That would require complete air 
> control and there is no attempt to do that in an mbaula.
So, please do not confuse the TLUD (which is MPF) with something that is 
lit at the top maintains its burning at the top.   This research paper 
is clearly NOT referring to what has become known as the TLUD 
micro-gasifier.

Yes, people can light fires at the top.   They can be just regular 
fires.   Light them at the bottom and they are just regular fires.    
That is why I am emphasizing MPF as being the important characteristic 
of TLUD stoves.   Others that are LIT on the top or bottom are not 
necessarily gasifiers.

The designations of UP and DD for updraft and downdraft are term for 
GASIFIERS (PHYSICAL DEVICES) WHERE THERE IS AN INTENTIONAL AND CLEAR 
SEPARATION OF WHERE AND WHEN THE GASES ARE CREATED AND WHERE AND WHEN 
THE GASES ARE BEING BURNED.

A TLUD is a gasifier.   Lighting coal or wood in a bucket is not a 
gasifier.   All fires involve gasification (a process), but that does 
not make the device (bucket, open air, tube, whatever) automatically to 
be a gasifier DEVICE.

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 9/20/2015 9:34 AM, Crispin Pemberton-Pigott wrote:
>
> Dear Paul
>
> >Please confirm:   Something like a bucket with holes in the bottom.
>
> Yes.
>
> No upper extension.
>
> Added during ignition. Removed once coked. Behaviour varies.
>
> No attempt to have a TLUD-type concentrator or directed horizontal 
> entrance of the secondary air.
>
> That is not special to TLUD’s. Upper holes serve as horizontal air 
> entrances.
>
> Just light one at the bottom (bottom burning only - BB) and the other 
> at the top (meaning that the pyrolytic front will be moving downward 
> through the stack of fuel, as migratory pyrolytic front MPF until it 
> reaches the bottom.)
>
> The two approaches are used. Top lit is advertised as ‘improved’ but 
> it goes back a long way. The top lit version does not mean an MPF. You 
> can only really get an MPF if it is a packed bed gasifier and 
> virtually no one is doing that.
>
>
> 2.  So the fuel-bed temperatures were always measured in the bottom of 
> the BB unit, but were measured at the position of the MPF as the MPF 
> progressed downward.   Right?   If not, please describe.
>
> Don’t know.
>
>
> 3.  How did the experimenters control (make hotter or less hot) the 
> fuel bed temperatures?
>
> Don’t know. I don’t think they did.
>
> 4.  How deep is the pile of coal fuel?
>
> Typical is < 150mm.
>
> 5.  Please describe the "secondary" burning.   Flames flickering on 
> the top?   tall, short, etc.
>
> Tall in the beginning and short after pyrolysis.
>
>
> 6.  And which way (BB or MPF)  is the common practice in South Africa?
>
> Bottom lit updraft (BLUD) is common, and TLUD is also common. MPF is 
> not going to be seen, not a real one. That would require complete air 
> control and there is no attempt to do that in an mbaula.
>
> Regards
>
> Crispin
>
>
>
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