[Stoves] Chimneys, rice husks [Ovens]

Sat Jun 15 05:42:38 CDT 2013

Ok agreed

On Sat, Jun 15, 2013 at 7:55 PM, Paul Olivier <paul.olivier at esrla.com>wrote:

> Stephen,
>
> Remember the context here: I have been talking about the direct combustion
> of rice hulls.
>
> Paul
>
>
> On Sat, Jun 15, 2013 at 4:40 PM, Paul Olivier <paul.olivier at esrla.com>wrote:
>
>> Stephen,
>>
>> Are you burning rice hulls at a temperature less than 450 C?
>>
>> Paul
>>
>>
>> On Sat, Jun 15, 2013 at 4:10 PM, Stephen Joseph <joey.stephen at gmail.com>wrote:
>>
>>> I paul
>>>
>>> Not if you use the design with an inner fire box and an outer pyrolysis
>>> chamber as is Mr Khois design.  In fact it is the main reason why I
>>> recommended this design configuration and sizing to PED.
>>>
>>> We did a large research project with the Australia Government research
>>> arm ACIAR to optimise the design.
>>>
>>> I have measurde the rice husk temperature in this outer chamber and it
>>> stays pretty uniform at around 450C after the initial drying and
>>> torrefaction phases.
>>>
>>>
>>> Regards
>>> Stephen
>>>
>>> On Sat, Jun 15, 2013 at 5:55 PM, Paul Olivier <paul.olivier at esrla.com>wrote:
>>>
>>>> But, Stephen, temperatures can rise above 900 C when burning rice hulls.
>>>> If we operate at low temperatures (450 C) in burning rice hulls, are we
>>>> not inevitably making a lot of smoke?
>>>>  Even at relatively low average combustion temperatures, will there
>>>> not be a tendency for hot zones to form within the combustor?
>>>>
>>>> Paul Olivier
>>>>
>>>>
>>>> On Sat, Jun 15, 2013 at 2:44 PM, Stephen Joseph <joey.stephen at gmail.com
>>>> > wrote:
>>>>
>>>>> All
>>>>>
>>>>> There has been a lot of work done on formation of crystobalite.  The
>>>>> rate of formation is both a function of time and temerature
>>>>>
>>>>> If you have low temperatures (450c) and short times (<60 minutes)you
>>>>> wont produce it.
>>>>>
>>>>> Mehta in India did a lot of work on this in the 80's and published a
>>>>> book on rice husk ash cement if I remember correctly
>>>>>
>>>>> Regards
>>>>> Stephen
>>>>>
>>>>>
>>>>> On Sat, Jun 15, 2013 at 5:20 PM, Paul Olivier <paul.olivier at esrla.com>wrote:
>>>>>
>>>>>> Tom,
>>>>>>
>>>>>> I found this news report:
>>>>>>
>>>>>> http://www.ipsnews.net/2009/10/thailand-renewable-energy-not-so-clean-and-green-after-all/
>>>>>> Not such a nice story.
>>>>>> I do not think it's a good idea to burn rice hulls or rice straw in
>>>>>> either power plants, brick kilns or household stoves.
>>>>>>
>>>>>> Paul
>>>>>>
>>>>>>
>>>>>> On Sat, Jun 15, 2013 at 1:10 PM, Paul Olivier <paul.olivier at esrla.com
>>>>>> > wrote:
>>>>>>
>>>>>>> Tom,
>>>>>>>
>>>>>>> I have read in many articles that cristobalite can form at
>>>>>>> temperatures of about 900 C.
>>>>>>> http://www.jicosh.gr.jp/old/niih/en/indu_hel/2004/pdf/42-2-24.pdf
>>>>>>> In burning rice hulls, temperatures can easily exceed 900 C.
>>>>>>> If cristobalite forms and is breathed in, human health is severely
>>>>>>> impacted: silicosis, tuberculosis, cancer and so forth.
>>>>>>>
>>>>>>> *Silica (SiO2) is a constituent of the ash produced by the
>>>>>>> combustion process. Different
>>>>>>> types of biomass fuels contain different quantities of silica. The
>>>>>>> International Agency for
>>>>>>> Research on Cancer has classified silica as a human carcinogen. Long
>>>>>>> term inhalation
>>>>>>> of airborne silica particulates can cause lung cancer or other
>>>>>>> related health problems.
>>>>>>> As rice hull ash contains high levels of silica (~15%), its use as a
>>>>>>> biomass fuel
>>>>>>> presumably increases the risk of developing silicosis-related
>>>>>>> illnesses, and care should
>>>>>>> be used in handling the ash.*
>>>>>>>
>>>>>>> http://www.reap-canada.com/online_library/IntDev/id_eco_sugarcane/7%20Strategies%20for.pdf
>>>>>>>
>>>>>>> *Silica (SiO2) is the main mineral component of rice husk ash (RHA)
>>>>>>> (85-90 per cent). It carries serious health risks, particularly to the
>>>>>>> respiratory system.*
>>>>>>> http://www.dhf.uu.se/pdffiler/cc7/cc7_web_art4.pdf
>>>>>>>
>>>>>>> Cristobalite can be present in both the ash and fly ash. If someone
>>>>>>> designs a stove to burn rice hulls or rice straw, he has to be sure that
>>>>>>> temperatures remain below the point of cristobalite formation.
>>>>>>>
>>>>>>> Paul
>>>>>>>
>>>>>>>
>>>>>>> On Sat, Jun 15, 2013 at 11:18 AM, Tom Miles <tmiles at trmiles.com>wrote:
>>>>>>>
>>>>>>>> Paul,****
>>>>>>>>
>>>>>>>> ** **
>>>>>>>>
>>>>>>>> After discussing rice hull combustion and gasification at some
>>>>>>>> length you are now saying this is dangerous. Why, specifically? You have
>>>>>>>> discussed the potential to emit cristobalite but there is no evidence of
>>>>>>>> the hazard it presents. What evidence do you have that burning rice husks
>>>>>>>> or rice straw is a health hazard?****
>>>>>>>>
>>>>>>>> ** **
>>>>>>>>
>>>>>>>> Tom ****
>>>>>>>>
>>>>>>>> ** **
>>>>>>>>
>>>>>>>> *From:* Stoves [mailto:stoves-bounces at lists.bioenergylists.org] *On
>>>>>>>> Behalf Of *Paul Olivier
>>>>>>>> *Sent:* Friday, June 14, 2013 8:56 PM
>>>>>>>> *To:* JJ Claire; Discussion of biomass cooking stoves
>>>>>>>> *Subject:* Re: [Stoves] Chimneys, rice husks [Ovens]****
>>>>>>>>
>>>>>>>> ** **
>>>>>>>>
>>>>>>>> JJ,****
>>>>>>>>
>>>>>>>> I would not recommend that you burn rice hulls ir rice straw.****
>>>>>>>>
>>>>>>>> In many cases this is quite dangerous.****
>>>>>>>>
>>>>>>>> Paul****
>>>>>>>>
>>>>>>>> ** **
>>>>>>>>
>>>>>>>> On Sat, Jun 15, 2013 at 9:40 AM, JJ Claire <pugoclaire at yahoo.com>
>>>>>>>> wrote:****
>>>>>>>>
>>>>>>>> Greetings one and all,****
>>>>>>>>
>>>>>>>> I visit the Philippines often and usually stay about six months a
>>>>>>>> year.  ****
>>>>>>>>
>>>>>>>> I often use a rice hull stove.  I would like to get a plan to build
>>>>>>>> a ****
>>>>>>>>
>>>>>>>> concrete stove.  I am also wondering if there is such a thing as
>>>>>>>> building ****
>>>>>>>>
>>>>>>>> an 'oven' using cement and/or concrete?  I would like to build one,
>>>>>>>> ****
>>>>>>>>
>>>>>>>> a white model if possible, [vice a black model], if such a plan is
>>>>>>>> ****
>>>>>>>>
>>>>>>>> available and if the technology would be practical.  We have a ****
>>>>>>>>
>>>>>>>> lot of rice hulls and not all that much firewood.  ****
>>>>>>>>
>>>>>>>> I would be open to heating the oven with firewood and then ****
>>>>>>>>
>>>>>>>> maintaining the heat level with or by burning rice hulls.  I have**
>>>>>>>> **
>>>>>>>>
>>>>>>>> a lot of rice hulls and want to make the best use of the hulls.****
>>>>>>>>
>>>>>>>> I currently use the wood ashes to make lye so I can make soap, ****
>>>>>>>>
>>>>>>>> but I have not used any ashes from rice hulls to make lye.  I****
>>>>>>>>
>>>>>>>> wonder if making lye with rice hulls is possible.****
>>>>>>>>
>>>>>>>> The rice hull stoves we use are sort of a metal pail with a wire
>>>>>>>> rack.  ****
>>>>>>>>
>>>>>>>> I am looking for a stove, hopefully one that is hot, medium and
>>>>>>>> cool, ****
>>>>>>>>
>>>>>>>> for cooking with rice hulls over a long number or years.   ****
>>>>>>>>
>>>>>>>> On our island, rice hulls are still burned to 'get rid of them',
>>>>>>>> and ****
>>>>>>>>
>>>>>>>> believe it or not, rice straw is still burned. I often ask
>>>>>>>> neighboring****
>>>>>>>>
>>>>>>>> farmers to bring me their straw and provide them a small bit of ***
>>>>>>>> *
>>>>>>>>
>>>>>>>> cash for doing so.  We use the rice straw for making compost.****
>>>>>>>>
>>>>>>>> We add some rice hulls to the compost.  Most of the rice hulls****
>>>>>>>>
>>>>>>>> are burned for fuel to cook with.  We add the char from the cooking
>>>>>>>> ****
>>>>>>>>
>>>>>>>> process to the garden.  I am wondering if we are making the best***
>>>>>>>> *
>>>>>>>>
>>>>>>>> use of the rice hulls and if the plans I am speaking of by post ***
>>>>>>>> *
>>>>>>>>
>>>>>>>> are available.  ****
>>>>>>>>
>>>>>>>> Please inform, I am open to suggestions and direction.****
>>>>>>>>
>>>>>>>> Blessings,****
>>>>>>>>
>>>>>>>> JJ****
>>>>>>>>
>>>>>>>>  ****
>>>>>>>>
>>>>>>>> *From:* "ajheggie at gmail.com" <ajheggie at gmail.com>
>>>>>>>> *To:* Discussion of biomass cooking stoves <
>>>>>>>> stoves at lists.bioenergylists.org>
>>>>>>>> *Sent:* Friday, June 14, 2013 5:02 PM
>>>>>>>> *Subject:* Re: [Stoves] Chimneys, rice husks****
>>>>>>>>
>>>>>>>>
>>>>>>>> [Default] On Fri, 14 Jun 2013 17:37:30 -0400,"Crispin
>>>>>>>> Pemberton-Pigott" <crispinpigott at gmail.com> wrote:
>>>>>>>>
>>>>>>>> >We are experimenting in Indonesia with draft-operated buoyancy
>>>>>>>> balancers to limit the pull to the ideal even when combustion conditions
>>>>>>>> change in the large wood stoves. They are easy and cheap to make. They are
>>>>>>>> mounted on the side of the stack of all oil furnaces.
>>>>>>>>
>>>>>>>> We have used them on pellet stoves (which have their own id fans) to
>>>>>>>> limit draught on an insulated ss chimney that rose through 4
>>>>>>>> floors. I
>>>>>>>> wasn't entirely happy with the idea as it raised the possibility of
>>>>>>>> the boiler room getting combustion products if the seal wasn't
>>>>>>>> good, I
>>>>>>>> would have been happier if the air was sucked from outside. In fact
>>>>>>>> there was subsequently a problem but this was down to poor
>>>>>>>> maintenance.
>>>>>>>>
>>>>>>>> AJH
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>>>
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>>>>>>>> site:
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>>>>>>>>
>>>>>>>>
>>>>>>>> ****
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Stoves mailing list
>>>>>>>>
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>>>>>>>> ****
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Paul A. Olivier PhD
>>>>>>>> 26/5 Phu Dong Thien Vuong
>>>>>>>> Dalat
>>>>>>>> Vietnam
>>>>>>>>
>>>>>>>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>>>>>>>> Mobile: 090-694-1573 (in Vietnam)
>>>>>>>> Skype address: Xpolivier
>>>>>>>> http://www.esrla.com/ ****
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Stoves mailing list
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>>>>>>>> site:
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>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Paul A. Olivier PhD
>>>>>>> 26/5 Phu Dong Thien Vuong
>>>>>>> Dalat
>>>>>>> Vietnam
>>>>>>>
>>>>>>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>>>>>>> Mobile: 090-694-1573 (in Vietnam)
>>>>>>> Skype address: Xpolivier
>>>>>>> http://www.esrla.com/
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Paul A. Olivier PhD
>>>>>> 26/5 Phu Dong Thien Vuong
>>>>>> Dalat
>>>>>> Vietnam
>>>>>>
>>>>>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>>>>>> Mobile: 090-694-1573 (in Vietnam)
>>>>>> Skype address: Xpolivier
>>>>>> http://www.esrla.com/
>>>>>>
>>>>>> _______________________________________________
>>>>>> Stoves mailing list
>>>>>>
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>>>>>>
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>>>>>> site:
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>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Stoves mailing list
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>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Paul A. Olivier PhD
>>>> 26/5 Phu Dong Thien Vuong
>>>> Dalat
>>>> Vietnam
>>>>
>>>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>>>> Mobile: 090-694-1573 (in Vietnam)
>>>> Skype address: Xpolivier
>>>> http://www.esrla.com/
>>>>
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>>>>
>>>>
>>>
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>>>
>>
>>
>> --
>> Paul A. Olivier PhD
>> 26/5 Phu Dong Thien Vuong
>> Dalat
>> Vietnam
>>
>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>> Mobile: 090-694-1573 (in Vietnam)
>> Skype address: Xpolivier
>> http://www.esrla.com/
>>
>
>
>
> --
> Paul A. Olivier PhD
> 26/5 Phu Dong Thien Vuong
> Dalat
> Vietnam
>
> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
> Mobile: 090-694-1573 (in Vietnam)
> Skype address: Xpolivier
> http://www.esrla.com/
>
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