[Stoves] Pasifier Video

rongretlarson at comcast.net rongretlarson at comcast.net
Mon Mar 12 22:38:53 CDT 2012


Alex and list 

Thanks for answers. Few new comments below. 

----- Original Message -----
From: "Alex English" <english at kingston.net> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Monday, March 12, 2012 7:43:51 PM 
Subject: Re: [Stoves] Pasifier Video 

Hi Ron, 
see answers below 

On 12/03/2012 5:49 PM, rongretlarson at comcast.net wrote: 



Alex cc List 

Nice work (again). 

Few questions: 

1. You sent in a "stoves" message on 12 Jan that had some similarities to, but also major differences from, this given below. Can you describe how and why the various differences? 


On February 6 I posted some pictures of the "natural draft Dasifier". This latest post is working with that basic arrangement. 
[RWL: I guess I now recognize "basic", but there are also some huge changes as well. The Feb. 6 photo is mentioned in stoves message 3035, and sends people to: 
https://plus.google.com/photos/100691739453894624566/albums/5706196233945639345 ] 

The big difference is that there is a bed of glowing/gasifying char below the vertical fuel hopper. It supports the fuel and limits its flow down ward. So within limits, the power level is controlled by the primary under grate air, just like most air controlled stoves. This is very effective if the both the ash and the fuel flows freely, as with premium( low ash) wood pellets. If I try to use oat hull pellets which have eight times the ash content and tend to hold their shape as a char-ash, it doesn't let fresh pellets slip down, it won't work. The wood pellets fire in a nozzle at the base of the hopper. I ran it with a 2 inch diameter 4 inch long nozzle for about 80 hours before I had a bridge and flame out. Not good enough. Now it is a 2.5 inch diameter X 4 inch long nozzle with the bottom inch reduced with a 2 inch insert. No problems since. 
[RWL: Now I see how primary air is controlled - but not specifically during a run. Insert a conical shape, etc.?] 

With chips, and there are many different qualities and sizes of chips, there is no nozzle. There tends to be some irregularity in chip flow/slippage down the tube. This results in power fluctuations and concurrent changes in combustion quality as gas production and excess air fluctuates. Still quite effective though. There is always more to learn, but especially with the chip. 

A second difference is the secondary air inlet. Much more controllable now than with the first outfit. 
[RWL: I can't pick this out. Can you describe what to look for?] 

<blockquote>



2. I can't see a reason for the name "pasifier", but my google search engine was sure you had mis-spelled "pacifier". I assume "P" might stand for "pellet"? How about the "as"? Yours seems to have some similarity to the "dasifier" - is that part of the name history? 

</blockquote>
Passive Gasifier, like passive solar, no pumps or fans, no electricity required. 

<blockquote>


[RWL: Got it. In the 6 Feb. note you gave credit to Das - but his unit was powered. It is great that yours is passive (possible because of tall chimney).] 

</blockquote>
3. You also indicated this was working for wood chips - which is welcome news because of presumed lower costs. Can you say more on costs? 

<blockquote>


</blockquote>
Pellets are now a commodity at 5-7 dollars a bag up here. Chips can be free to what ever mulch sells for. We buy them by the truck load for 35-55 dollars per tonne. 
[RWL: What weight to the pellet bag? 40 pounds maybe?] 

<blockquote>



4. Do you have (or could have) any control on output power? For how long can the indicated tall supply last - and how much does power change during this period? 

</blockquote>
Yes but there is a minimum where the fire slowly creeps up the nozzle below say 5 KW. At 8 KW it goes for about 2 hours on a "tank". The longest continuous run has been 14 hours. 

<blockquote>



5. Any chance that this can be run as a charcoal-maker? (with some re-design assumed/allowed). 

</blockquote>
Yes, but with augers, it isn't a Pasifier. 
[RWL: I am thinking batch-passive. A (slightly?) downstream large "pit" to "dump" char?. The difference from TLUDs is still quite considerable . 
Since fans and electricity are topics of some interest on this list, can you sometimes argue for a fan? And therefore (presumably) an auger? ] 

<blockquote>



6. You showed 0.1 inch water pressure difference. At 
http://www.gutenberg.org/files/22657/22657-h/chapters/chimneys.html 
they show .67 inches for 100 ft chimney. Is yours in the neighborhood of 14-15 feet? (This assuming closer to 500 oF, per their example) 

</blockquote>
Close enough. I have started it with as little as .02 inches of H2O, though slowly. The stack of the wood stove exiting the room is usually in the 300-400F range. 
[RWL: Crispin asked about the much higher reading for temperature at end of most recent video. Where was that (500+ oC) temperature measured?] 

<blockquote>



7. Your previous video concentrated on the flame inside the (modified) original stove. Presumably this time no flame to be seen there? 

</blockquote>
Yes it should be completed under the cooking stove top. 

<blockquote>



8. We haven't heard anything on your earlier moving grate burner modifications for the greenhouse. Have you been getting some char out? (presumably chips?) 

</blockquote>
We have been working on feed stock quality and have just now received material which should be good. One of several hurdles. Some researchers are keen to do more work with us, so we will make some char over the next couple of weeks. 

<blockquote>


[RWL: Good to hear about the researchers. A lot should be beating down your doors. I think you have one of the best charcoal-makers around. Presumably there are thousands of boilers (whose grates and their speed) could be similarly modified at low cost.] 
</blockquote>


<blockquote>



Thanks again for keeping us informed. Ron 

</blockquote>

I try, 
Alex 

<blockquote>


[RWL: Repeat "thanks". I am beginning to understand better. Ron ] 


----- Original Message -----
From: "Alex English" <english at kingston.net> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Sunday, March 11, 2012 9:12:01 PM 
Subject: [Stoves] Pasifier Video 

Dear Stovers, 
I have been using my latest version of the gravity powered 'Pasifier' 
in both wood pellet and chip fired modes for the last month. 
Still learning but I'm running out of winter and therefore the need. 
Check it out at; 
http://www.youtube.com/watch?v=mWP15Eek4Xo&feature=youtu.be 
<http://www.youtube.com/watch?v=mWP15Eek4Xo&feature=youtu.be> 

Alex 

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</blockquote>


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