[Stoves] Heavy metal-pipe gasifier Re: Idea for cooking on a TLUD

[Crispin Pemberton-Pigott]

Dear Paul

 

>The metal-pipe version you described could have some practical implications for use with biomass as well as coal.   

 

Correct – it can burn anything. It will do best with a particle size that is 1/10th of the diameter.


We will assume that scrap pipe is available and cheap.



In Asian countries district heating pipes are widely available in various conditions from the scrapyards. There are many miles of it in Ulaanbaatar, for example.


Pipe will withstand the corrosion well.

 

They tend to be 4-10mm thick. They can take a lot of heat for a long time.

Pipe of such dimensions will be emptied / cleaned at a door on the side near the bottom (or with a trap-door through the bottom which would be more involved and require legs/supports.)  There would be no allowance for tipping over to dump out char or ash.



There is a grate 100 mm above the bottom with 7mm gaps. IT is loose and can be lifted using a wire hook pushed through the ash. When it is lifted it dumps everything on the grate (which might include stones) into the bottom space. There is an air control door on the bottom though which the ash can be scooped using a hooked plate.


The empty unit will stay hot/ warm for quite a while, so it probably should not be reloaded and reignited as a TLUD / MPF unit right away.   (We lack experience about this.)

 

This has proven, in Ulaanbaatar, not to be a problem, even with very hot ceramic linings (this stove mas no lining). Refuelling the hot stove and relighting on top showed no tendency to over-evaporate volatiles even using very high volatile fuel. It is just not an issue. Coal is cold and quickly cools everything down. It is possible that pellets would be an issue, but that would depend on the moisture content so it could work some of the time.


After a TLUD operation with MPF (migratory pyrolytic front), the fire will be at the bottom.   The unit COULD be continuously feed additional fuel from the top, opperating as a traditional updraft gasifier.   

 

I was able to successfully add coke from previous burns, as described before.

 

Note that this would be bottom burning like an incinerator, which generally causes worse emissions unless additional adjustments are made.   

 

Not the case. It was just fine. Nothing was changed. Remember that fuel size is important as it functions somewhat like a packed bed gasifier.

 

The entry points and amounts of air (primary and secondary) can greatly impact this performance.  For some societies and situations, this might be appropriate.



The secondary air was fixed and would probably be adjusted with the fuel composition, however that said, the fuel was at least sub-bituminous to bituminous coal and it did not smoke at all after the wood was well lit. Once the pyrolysis is complete, there is no chance of smoke. All coal stoves burn very cleanly at some point. The problem is adding fuel on top of an existing fire which if avoided can dispense with PM emissions almost entirely. Certainly 99%.


REQUEST:
Who has conditions to do the development work about this type of device?   NOT a tinsmith's job!!!  Please volunteer.   Or make a request for some minor financial assistance.   



In theory it could be done with an angle grinder, hammer and drill – not even welding. It depends how simple you want to go. Most places have arc welding.


Remember that this can have significant usefulness in colder climates where room heating is also of value.

 

Water heating is surprisingly important as a fuel consumer. I have just seen that at least as much fuel is used for heating water as heating the home. Dedicated water heaters are under-discussed.


Crispin's time in Tajikistan is limited.   We need some continuity.   Maybe a team effort.   We can start by bringing together the various messages about this, including Crispin's photos.  

 

I left TJ and went to Kyrgyzstan for a week and returned to Canada already. Drawings will be available soon for all these stoves. In places where only dung is available there might be some interest in the “bricked stove” approach. It is easy, cheap and lasts a long time.


I will participate, but I do not work alone any more.  Make yourself known!!!



Thank you, this is important work. We have a continent to transform.

 

Crispin

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20160318/89fe61af/attachment.html>