[Stoves] Rice husk briquettes in Vietnam was Re: Cuber and size of densifying machines

Ronal W. Larson rongretlarson at comcast.net
Sun Mar 16 08:49:44 CDT 2014


Anh, list etal

	Thanks very much for very complete responses to many questions.   The prices of your stove are very low compared to the prices of the fuel.  The payback period must be measured in weeks, measured against the three stone norm

	I know of no other stove that refers to biomass boxes.  I think I see them in the users guide (only in Vietnamese).  Is there air flow up through them or do they operate more as retorts - something like the Anila stoves (where pyrolysis gases exit at the bottom)?   Since the “boxes" would not be practical in a cylindrical geometry, this could be another rationale for your square design.  Apparently only now sold as an option, can you describe their use and theory of operation, and their economics (payback time).

	I do not have a good answer on soot buildup.  I vaguely recall list members using some coating - I hope they can repeat.

	Best of luck in your young business.  I hope you will keep us informed of further progress - especially on char buyback.

Ron

On Mar 16, 2014, at 6:26 AM, Anh Nguyen <ntanh at greengenvn.com> wrote:

> Dear Ron and all,
> 
> Thanks for your comments. 
> 
> Most popular in Vietnam are the log style briquette and pellets but pellets
> are not for retail due to prices. Briquette prices ranging from 40c-1usd/kg
> depending mostly on seasonal shortages of RH supplies (mostly happen in
> north of Vietnam) while pellets are around 1.2-1.5USD/kg. These are at
> producer workshop price, transportation and distribution can be varies in
> different regions.
> 
> So far all customers burnt all the charcoal. For normal cooking process,
> they will prepare other foods first (boil,fry,...) then end it rice so the
> charcoal heat is nice for it, so they can only get biochar from biomass
> boxes at the end. There's a charcoal market for cooking need, but not
> biochar for soil enhancement yet. I am working on a plan to buy back the
> biochar from stove users but it still on planning for now. I also want to
> promote more about the use of biochar for soil and crops but it would be
> better coming from some organization or agency well known in related fields.
> In some area, due to they have abundance of wood, there's no demand for
> utilizing agriculture wastes for cooking.
> 
> All stoves can use pellets, we tried, but since there's no pellets for
> customers so it's only our in house test. Most customers using wood log for
> cooking now so it's easier for them to switch from three stone to another
> wood stove, but there's also many customers like to use the biomass boxes to
> cooking using their garden waste, straw or saw dust (in carpenter villages).
> We first introduce a stove that always come with 2 biomass boxes but after
> first round of introduction, have to change it to optional biomass boxes and
> more sizes to meet the need of people in various areas.
> 
> About >90% of the tryers buy the stove but the total number is not as big as
> expected. Most people buy the stove just after seeing demonstration, they
> dont want to borrow then have return  and in some case need some deposit to
> retailers. Most of our retailers are cooking with wood daily too and all we
> require them to do is to bring the stove out to shop front and cook there
> instead of inside the kitchen, so we can have a live demo every day.
> 
> Prices are no secret, retail prices (max that retailers are allowed to sell
> at) are 8.5USD, 12USD, 14.5 USD, 22USD from smallest to biggest. The most
> popular stove is the medium one at 12USD, good for family daily cooking.
> Some retailers sell at lower price depending on our promotional programs
> from time to time. As stove are not something that people must buy,
> customers tend to buy more after their harvest, so demand varies between
> areas depending on what they are farming and harvest time.
> 
> We do have soot build up problem but many users here already have a way to
> fix it, even with their three stone stoves. They but a metal plate with
> round hole in middle on the stove so the flame only directly touch the
> middle of the pot bottom, not the sides and keep the pot clean although it
> reduce thermal efficiency a bit. Please help recommending methods to reduce
> the soot build-up.
> 
> The square shape did come from manufacturing demand. As we follow the
> inclusive business model which I want to make only the stove parts and ship
> to local people to assemble the stoves. That help shifting jobs from city to
> rural areas plus cutting warehouse, workshop, transportation, packaging cost
> so only a square stove can do it. Our stoves require no welding at all,
> except the steel frame of the largest stove (to handle heavy pots >50
> liters), and assembling only require a smallest power drill. We also
> outsource the making of several simple parts to some low income families, we
> supply prepared materials, tools, training and they can work from home.
> 
> I know that heat distribution will not be uniform but so far we have no
> problem with pyrolysis. All biomass in the biomass boxes, even not so dry
> one, fully turn to biochar at the end of normal cooking process, this also
> work with the test of larger size biomass boxes too (10cm deep vs normal of
> 5cm). 
> 
> Regards,
> 
> Anh
> 
> 
> 
> 
> 
> -----Original Message-----
> From: Ronal W. Larson [mailto:rongretlarson at comcast.net] 
> Sent: 16 March, 2014 2:31 AM
> To: Discussion of biomass; ntanh at greengenvn.com
> Cc: Michael Shafer - Thailand; Kent Good - Cambodia; atbelonio at yahoo.com
> Subject: Re: [Stoves] Rice husk briquettes in Vietnam was Re: Cuber and size
> of densifying machines
> 
> Anh, list,  et al:
> 
> 	1.  Thanks for the new information on pellets in Viet Nam.  It is
> good to hear the husks are now being put to use.  The rating of 4100 kcal/kg
> is a bit more than 17 MJ/kg.   What are typical wholesale and retail prices
> for these pellets/briquettes?  Do the different shapes (and probably
> densities) have different prices?
> 
> 	2.  I recommend your web site to others.   You seem to have a nice
> product line.  Glad to see the word "biochar" there.   If you stop your
> pyrolysis at the right time, what maximum percentage char yield are you able
> to obtain?  Is there a market for the char and if so at what price relative
> to the input fuel?
> 
> 	3.  All of your 4 size stoves seemed to focus on wood.  Can they
> work with pellets - and what operational cost difference would you expect?
> Do you expect most of your customers to get sticks and then stack
> vertically?
> 
> 	4.  It seems like a good idea for you to allow a two day trial
> period.  What percentage of those who take up that offer then buy?   It is
> perhaps impolite to ask the prices of the four sizes, but if not, perhaps
> you could give those.  Since we have all your dimensions, just knowing the
> ratio of prices for the four different models would be very interesting
> 
> 	5.  The main difference I note over other TLUDs is that you seem to
> only have secondary air at the very top - and hence a very tall flame.  Do
> you have any problem of soot buildup on the pots?
> 	
> 	6.  Another difference is having a square rather than cylindrical
> geometry.  This probably has many manufacturing advantages, but possibly not
> on uniformity of pyrolysis.  Does the char seem to be roughly the same in
> the corners as the center?
> 
> Thanks for doing what you are doing.  Best of luck.
> 
> Ron
> 
> 
> On Mar 15, 2014, at 11:26 AM, Anh Nguyen <ntanh at greengenvn.com> wrote:
> 
>> Dear Paul and all,
>> 
>> Below are some links for what we have in Vietnam, sorry that they are 
>> in Vietnamese but you can see some machines and rice husk products 
>> http://mayepcuitrau.com/ 
>> http://tmptrade.com/product.html?gclid=CPeW5YPylL0CFacF4goddiwA2Q
>> 
>> I've just briefly visited Mekong delta last month and met several 
>> people in rice milling business to discover the chance to make rice 
>> husk briquette there and was very surprise too with the fact that I 
>> found. Mekong delta is the heart of Vietnamese rice production, 
>> there's a lot of rice mill there and all of them (as far as I know) 
>> already have a buyer for their rice husks. They often sign year long 
>> contract to buy all the rice husks, most for making 
>> briquettes/pellets, some for direct use (making bricks,...). In many 
>> area , people also use rice husk briquetted for daily cooking, most of 
>> them burn as normal wood in three stone stoves. Small rice mill there can
> handle 300-400 tons rice/day, producing 60-80 tons rice husks.
>> 
>> In the north of Vietnam, due to small scale production of rice, we are 
>> running short of rice husk briquette now, all producers have no stock 
>> to sell even when the price already up by 50%. Most rice husk 
>> briquette producers in the north of VN have relatively small capacity 
>> 300-600 tons/months due to the supplies of rice husks, supplying 
>> ability also depend a lot of harvest season.
>> 
>> The largest importers are Japan and Korea. Largest local buyers are 
>> food processing and garment industry.
>> 
>> For the ash from rice husk briquette, all manufacturers offer to buy 
>> back the ash from customers. Due to high silica content in the ash, it 
>> consider somehow toxic waste" but at the same time, some fertilizer 
>> and construction material need it for the use so its a win-win-win 
>> situation for everyone involved.
>> 
>> 
>> As for equipments:
>> 
>> The above briquette machines are local made, we have a few makers in 
>> Vietnam. You can find similar from China too. Machines need 3 phrase 
>> power, 7-15kw for 200kg-1ton/hr, price range is around 2000USD-5000USD.
>> 
>> Pellets machines: ring die system from China cost ~40kUSD for 
>> 1-2ton/hr, but for export quality (need to deal/reduce silica first), 
>> there are some system from Euro installed in the region but I'm not 
>> sure about the brand and price (heard of 150k range). I will try to find
> more info on this.
>> 
>> I also visited Henan, China last summer looking for briquette and 
>> pellets machines. There were some good machines there, some may work 
>> with grass or straw. I would be very happy to discuss further if anyone
> interested.
>> 
>> As about myself, my background is business and I m running a small 
>> private start up in Hanoi. Our main focus is to utilize the 
>> agriculture residues (which e have million tons in Vietnam yearly) in 
>> a more useful way rather than burning as waste. Our current product is 
>> a ND TLUD which use wood + biomass, just started to make and sell for 
>> about 6 months with some positive feedback.
>> 
>> 
>> Anh
>> 
>> Anh Nguyen
>> General Director
>> Green Generation JSC
>> 30A Tran Hung Dao St., Hanoi, Vietnam
>> Tel + 84 91 242 6666
>> Email: ntanh at greengenvn.com
>> Website: www.greengenstove.com
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> -----Original Message-----
>> From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On 
>> Behalf Of Paul Anderson
>> Sent: 15 March, 2014 9:06 AM
>> To: Discussion of biomass cooking stoves; Michael Shafer - Thailand; 
>> Kent Good - Cambodia; alexis belonio
>> Subject: [Stoves] Rice husk briquettes in Vietnam was Re: Cuber and 
>> size of densifying machines
>> 
>> Dear Anh,
>> 
>> On behalf of many of us, I request that you send to us more 
>> information about the rice husk briquette processes and equipment and
> costs, etc
>> that you mention are so well established in Vietnam.   This is VERY 
>> important and is not well known to us. Maybe there are some reports you 
>> could send.    Or you could ask others to assist to provide us with the 
>> information.
>> 
>> Thank you in advance.
>> 
>> And we are interested in getting to know your better, your employment, 
>> training, etc.
>> 
>> 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 3/14/2014 9:20 AM, Tuan Anh wrote:
>>> Robert and Richard,
>>> 
>>> Vietnam used to have problem with excess rice husks at mills too, but 
>>> now
>> they all make rice husk briquette, pellets so it turn from waste to 
>> tradable goods. We have many rice husk pellets makers here for both 
>> domestic and export.
>>> 
>>> As far as I know, dealing with high abarisve silica in rice husk 
>>> require a
>> much more expensive equipment. Low cost rice husk briquette machines 
>> can serve well for simple tasks such as daily cooking or simple 
>> commercial/industrial production.
>>> 
>>> Anh
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On Mar 14, 2014 8:32 PM, Richard Stanley <rstanley at legacyfound.org>
> wrote:
>>>> Robert
>>>> 
>>>> We have seen the same experience described by many in the wet 
>>>> processing
>> of briquettes, but with the wet process,  it was about abrasion to the 
>> blenders and molders hands, as it is very much a hands-on process.
>>>> However we found a different way to handle them for our needs-- at 
>>>> least
>> in Mbale Uganda in 2007.
>>>> 
>>>> In Mbale, rice husks were piled several meters high and spread out 
>>>> over
>> 100 meter wide mounds all from the local rice mill.
>>>> With the rains, these mounds would begin to decompose --more like 
>>>> decay--
>> from within, leaving large voids beneath  --and invisible on-- the
> surface.
>> Many children  playing on them were reported to have fallen in and 
>> been badly burned .  We were glad to discover that this glutinous mass 
>> was an excellent binder and in-filler for the wet process briquettes 
>> The abrasive properties of the original husk were abated in the decay
> process as well.
>> Rice husk blended briquettes were one variety of briquettes being made 
>> by the Uganda United Womens Association- Joint.
>>>> 
>>>> The UUWA-J is  headed by Vicky Akello. She and her team are really 
>>>> great trainers by the way and have trained all over Uganda and 
>>>> western Kenya ever since we first met in 2008. A contact for Vicky 
>>>> is
>>>> : Akello victoria <uuwaj at yahoo.com>
>>>> 
>>>> Richard
>>>> 
>>>> 
>>>> 
>>>> On Mar 6, 2014, at 11:28 PM, robdeutsch44 wrote:
>>>> 
>>>> Rice hulls are a very difficult material to pelletize with because 
>>>> of the high silica content makes it very abrasive on the dies and 
>>>> moving
>> parts.
>>>> Better to use rice hulls at point of generation (the rice mill) and 
>>>> use bulk gasifier.... Just my two cents :-)
>>>> 
>>>> Robert in Cambodia
>>>> 
>>>> 
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