[Stoves] Torrifaction topics Re: Pellet stoves - risks

Paul Anderson psanders at ilstu.edu
Wed Sep 9 10:20:43 CDT 2015


Frank and Stovers,

My simplistic interest in the "induced drying" of biomass fuels is 
related to improving the user-acceptance of the TLUD cookstoves and the 
establishment of some fuel marketing chain.   The degree of drying / 
torrification would be market driven, not related to emissions or 
technical characteristics of the resultant fuels.

As the degree of drying / heating of the fuels increases, the cost of 
that processing will rise.   So I favor the minimum treatment that will 
benefit the customer and will justify the increase in fuel price.

A favorable situation would be to use essentially waste heat to prepare 
the future fuel supplies.  Or expend a small amount of fuel to prepare a 
much larger amount of fuel that will be sold with sustainable profitability.

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 9/8/2015 3:55 PM, Frank Shields wrote:
>> Dear Paul,
>>
>> Making batches of different degrees of torrification biofuels is one 
>> thing and then testing and interpreting the results is another.
>> Do we measure success on emissions or time it takes to boil water? 
>> And them we have other variables like bulk carbon density and 
>> particle carbon density. Volatiles and adding moisture. Size and 
>> shape will be important.
>>
>> So once we figure out a way of making constant quality material for 
>> testing there is still a lot of research work to do. Agreeing on what 
>> we use as a measure of success is the first.
>>
>> regards
>>
>> Frank
>>
>>
>>
>> Frank Shields
>> franke at cruzio.com <mailto:franke at cruzio.com>
>>
>>
>>
>>
>>> On Sep 6, 2015, at 5:32 AM, Paul Anderson <psanders at ilstu.edu> wrote:
>>>
>>> Dear all,
>>>
>>> While agreeing with Frank and Dean, I suggest that there are 
>>> sufficient "degrees of torrification" that we should subdivide the 
>>> discussion.
>>>
>>> 1.  Wet or green wood      High moisture content (MC)
>>> 2.  Dried in 20% MC range
>>> 3.  Dried to 10% MC or less
>>> 4.  Kiln dried   (heated to ???? degrees C)
>>> 5.  Super dried (heated to maybe 120 C)
>>> 6.  Toasted (slightly browning)    120 to 180 C ???
>>> 7.  Early torrified                     180 - 240  C ??
>>> 8.  Fully torrified                240 - 300 C  ??
>>> 9.  Undergoing pyrolysis     above 300 C ???
>>> 10.  And then we have different "chars" based on temperatures during 
>>> production, 400 C,  450 C,  550 C, 700 C, 900 C
>>>
>>> LOTS of question marks there.   Frank and others can refine this 
>>> much better.    Issues of MC and temperatures and "names" (and 
>>> related to sufficient time to have the heat impact reach the center 
>>> of the pieces of biomass, not just flash heating), and probably more 
>>> variables.
>>>
>>> To just say "torrified" leaves too many uncertainties and possible 
>>> mis-understandings / assumptions by the large number of readers in 
>>> different cultures and with different experiences.
>>>
>>> I can say that TLUD stoves (when properly made and with consistent 
>>> MC in the fuels) work very well with the 3, 4, 5, and 6 (above) 
>>> fuels.   They do not like much moisture content, and they do not 
>>> want the fuel to be already partially charred.
>>>
>>> Reasonable quality fuel supply is so important for TLUD 
>>> acceptance.   More work could be done about this.
>>>
>>> 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 9/5/2015 11:45 PM, Frank Shields wrote:
>>>> Dear Dean, Stovers,
>>>>
>>>> I have not worked with stoves but working with all types of pellets 
>>>> (paper, manures, etc.) and good quality wood pellets I find they 
>>>> burn in pipes very poorly and seem they are really just good for 
>>>> pellet stoves dropping in one at a time.
>>>> I think you may be on to something in regards to torrifying to some 
>>>> extent before using to get a cleaner combustion. I see the real 
>>>> challenge is quality control because torrification takes place in a 
>>>> very narrow range and it is so easy to have a ‘run-a-way’ 
>>>> combustion that heats higher than the setting you want. I was able 
>>>> to achieve that in my pipes but only after much practice and   s l 
>>>> o w l y    raising the temperature to desired amount. Not sure how 
>>>> this would be done commercially.  It would be a very interesting 
>>>> project.
>>>>
>>>> We also may be able to get clean combustion by finding constituents 
>>>> in the pellets (and all biomass for that matter) that create these 
>>>> large organic volatile structures that give problems and eliminate 
>>>> them from the fuel.
>>>>
>>>> Regards
>>>>
>>>>
>>>> Frank
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Frank Shields
>>>> franke at cruzio.com <mailto:franke at cruzio.com>
>>>>
>>>>
>>>>
>>>>
>>>>> On Sep 3, 2015, at 12:28 PM, Dean Still <deankstill at gmail.com> wrote:
>>>>>
>>>>> Hi Frank,
>>>>>
>>>>> After limited experience in Uganda and China my experience is that 
>>>>> it's not easy to make clean burning recipes for biomass pellets.
>>>>>
>>>>> Seems like the torrified pellets emit less PM but we need to do 
>>>>> more tests.
>>>>>
>>>>> Best,
>>>>>
>>>>> Dean
>>>>>
>>>>> On Thu, Sep 3, 2015 at 8:44 AM, Frank Shields <franke at cruzio.com> 
>>>>> wrote:
>>>>>
>>>>>     Dear Chispin and stovers
>>>>>
>>>>>
>>>>>     Of course no mention of the quality of the pellets! In the
>>>>>     U.S. The go through standard testing and results labeled
>>>>>     On bags. But pellets are made of all sorts of materials and
>>>>>     energy values and volatile profiles.   It would seem this
>>>>>     would be part of the discussion.
>>>>>     Thanks
>>>>>     Frank
>>>>>
>>>>>     Sent from my iPhone
>>>>>
>>>>>     On Sep 3, 2015, at 6:13 AM, Crispin Pemberton-Pigott
>>>>>     <crispinpigott at outlook.com> wrote:
>>>>>
>>>>>>     Dear Friends
>>>>>>
>>>>>>
>>>>>>     There is a broad move around the world to create pelleted
>>>>>>     fuel from biomass and burn it in tighter spaces. This report
>>>>>>     was noted in the Alliance for Green Heat newsletter:
>>>>>>
>>>>>>
>>>>>>     *Updated on the Mt. Vernon pellet stove recall*
>>>>>>     <http://r20.rs6.net/tn.jsp?f=001d7dcszljjgfEKYA31aaHyRsMRRejQSaDUDJHpy5B3lPW1W0QcteHERbDFukIhEc2-_1cKtvym49J_ai7zvt1WWN26UenG3N6joIskOVraQhcc__S5dpEwVlcw8pbpwWuwRufyvZSstnraBJTXAbr2wOPL-tX7Wypj3swduscC5I1Staun8b2olWMeGwuEsLEKsSA0qsYd2J1B5b7fDXOH7vLn_jPI3y12xty5nULquL9LCJu6LE7P-Ysu5qiL45LFwfyKNL4feu5XOzEawUh0a7X5VAZM8fb7F4K1l1kHGeFIFftvkxNTEEi9J_I05V6LKmiIZSk4GOQXJRAMRf5NDba52L-Wn_9jVkbpqju9Kifq8bMZm_xowV5Qn2NerYbUfu00_a4isbrvL9gktLkSQ==&c=WnPhxOQ3V-ic1ZJ3NBDpcipfRPq-UdIrBKPYwMfkxe-_CRS45fkQ4w==&ch=gnDbpciWOWhz6yV0o8Zdcoli15r_rpgR21xk0iBJKKi_KYRnwLVmTw==>
>>>>>>
>>>>>>     Last month, we reported on the recall of 2,000 Mt. Vernon E2
>>>>>>     pellet stoves after about 6 experienced explosions that
>>>>>>     shattered the glass in the front door. No injuries have been
>>>>>>     reported. The Alliance wrote to HHT asking for clarifications
>>>>>>     about what caused the malfunction and whether the stove would
>>>>>>     be 3rd party tested again for safety. *Click here*
>>>>>>     <http://r20.rs6.net/tn.jsp?f=001d7dcszljjgfEKYA31aaHyRsMRRejQSaDUDJHpy5B3lPW1W0QcteHEfKhE4oT8BuuAHDwJ1L0g7GrKo5I0xEbbDvkpCt65Xds638GUTKpc9WxdvAozGBIprVOl7vL1wQKB10dTQFUofpAQnr3z9i2zwxCfiQA3rCg4PVvKxSMWgMWDhYiC_fJ7rGJlBpUwsdpb9A-KCa9c_WZg3sRbG1GpSOEsBvotEVw3FLKELU68l1aktAt4KqIrr-AbESuj8iSP6u9wdRQU3L5aMshSI5ocFejIUjrSB94PP9Q2h_zrmWcq3brFPbj1VqWZSiFfmDp50WpCw2b2SOvJ-9NqzbOgn8sgdzIHO2tNWqczgkuFI6d7bzwPt4D_g==&c=WnPhxOQ3V-ic1ZJ3NBDpcipfRPq-UdIrBKPYwMfkxe-_CRS45fkQ4w==&ch=gnDbpciWOWhz6yV0o8Zdcoli15r_rpgR21xk0iBJKKi_KYRnwLVmTw==>for
>>>>>>     a copy of the HHT response.
>>>>>>
>>>>>>
>>>>>>     The drive to create better combustion often means having a
>>>>>>     staged gasification-then-burning type of design. That may be
>>>>>>     a source of problems.
>>>>>>
>>>>>>
>>>>>>     I know of at least one instance of a very modern TLUD coal
>>>>>>     stove explosion in Ulaanbaatar when the operator refuelled it
>>>>>>     with a significant amount of lignite (high volatiles) while
>>>>>>     it was already very hot. This generated a huge amount of
>>>>>>     combustible gas while simultaneously extinguishing the gas
>>>>>>     flame.  Eventually it heated up to the point that the gas
>>>>>>     ignited and it blew flaming fuel out of the top of the stove,
>>>>>>     around the room.  A public education campaign tried to
>>>>>>     prevent exactly this sort of mis-operation.
>>>>>>
>>>>>>
>>>>>>     Regards
>>>>>>
>>>>>>     Crispin
>>>>>>
>>>>>>
>>>>>>     _______________________________________________
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>>>>>>
>>>>>
>>>>>     _______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>> -- 
>>>>> Dean Still
>>>>> Executive Director
>>>>> Aprovecho Research Center
>>>>> PO Box 1175
>>>>> 76132 Blue Mountain School Road
>>>>> Cottage Grove, OR 97424
>>>>> (541) 767-0287
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>>>>
>>>>
>>>>
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