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 <[email protected]>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 <[email protected]>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 >> <[email protected]>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 <[email protected]>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 >>>> <[email protected]>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 <[email protected]>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:[email protected]] *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 <[email protected]> >>>>>> 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:* "[email protected]" <[email protected]> >>>>>> *To:* Discussion of biomass cooking stoves < >>>>>> [email protected]> >>>>>> *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" <[email protected]> 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 >>>>>> >>>>>> _______________________________________________ >>>>>> Stoves mailing list >>>>>> >>>>>> to Send a Message to the list, use the email address >>>>>> [email protected] >>>>>> >>>>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>>>> >>>>>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>>>>> >>>>>> for more Biomass Cooking Stoves, News and Information see our web >>>>>> site: >>>>>> http://stoves.bioenergylists.org/ >>>>>> >>>>>> >>>>>> **** >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Stoves mailing list >>>>>> >>>>>> to Send a Message to the list, use the email address >>>>>> [email protected] >>>>>> >>>>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>>>> >>>>>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>>>>> >>>>>> for more Biomass Cooking Stoves, News and Information see our web >>>>>> site: >>>>>> http://stoves.bioenergylists.org/ >>>>>> >>>>>> **** >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> 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 >>>>>> >>>>>> to Send a Message to the list, use the email address >>>>>> [email protected] >>>>>> >>>>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>>>> >>>>>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>>>>> >>>>>> for more Biomass Cooking Stoves, News and Information see our web >>>>>> site: >>>>>> http://stoves.bioenergylists.org/ >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> 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 >>>> >>>> to Send a Message to the list, use the email address >>>> [email protected] >>>> >>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>> >>>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>>> >>>> for more Biomass Cooking Stoves, News and Information see our web site: >>>> http://stoves.bioenergylists.org/ >>>> >>>> >>>> >>> >>> _______________________________________________ >>> Stoves mailing list >>> >>> to Send a Message to the list, use the email address >>> [email protected] >>> >>> to UNSUBSCRIBE or Change your List Settings use the web page >>> >>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>> >>> for more Biomass Cooking Stoves, News and Information see our web site: >>> http://stoves.bioenergylists.org/ >>> >>> >>> >> >> >> -- >> 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 >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> >> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >> >> for more Biomass Cooking Stoves, News and Information see our web site: >> http://stoves.bioenergylists.org/ >> >> >> > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://stoves.bioenergylists.org/ > > > -- 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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