[Stoves] [Gasification] Grass Fireballs burn cleaner than wood

[Tom Miles]

Jeff,

It would be interesting to measure the dry matter loss from your retting
process. 

Composting can work the other way - reducing the carbon increases the
relative ash which reduces the heating value.

Tom 

-----Original Message-----
From: stoves-bounces at listserv.repp.org
[mailto:stoves-bounces at listserv.repp.org] On Behalf Of Jeff Davis
Sent: Thursday, December 28, 2006 9:05 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] [Gasification] Grass Fireballs burn cleaner than wood

On Thursday 28 December 2006 04:52 pm, Tom Miles wrote:
> Direct combustion of grasses can produce significant emissions due to the
> volatilization of inorganics and production of submicron particulates.
> Fireballing or wet processing such as holey briquetting would reduce this
> significantly by removing soluble inorganics. But there may be
applications
> where charcoal production is a viable alternative as it has been with the
> sugar cane tops and leaves.

Below is some interesting information about retting. Source; VITA Tech.
Paper 
#46.

My retting may be beyond their retting. In other words, maybe my fuel value
is 
less.


 
"RETTING AND PRESSING
 
Partially decayed and processed cellulosic materials give a much
higher heating value than if the materials are simply dried.  For
example, dried rice straw (10 percent moisture content) has a
heat value of only 3,000 BTU/pounds (7 million joules/kilogram
[J/kg] or 0.0698 gigajoules/kilogram [GJ/kg]), but this will
increase to between 7,500 (17.4 million J/kg or 0.0174 GJ/kg) and
12,000 (28 million J/kg or 0.0279 GJ/kg) when the material has
partially rotted before it is dried.   In the Philippines, the
MAPECON research group has set up a pilot plant producing such
fuel, with 25 percent moisture content and an average of 10,000
BTU/pounds (23 million J/kg or 0.0232 GJ/kg) which they call
`green charcoal,' at the rate of one ton per hour.   The group
reports that it is very competitive with other types of fuel."


Best Wishes,

Jeff






-- 
Jeff Davis
Somewhere 20 miles south of Lake Erie, USA
http://www.velocity.net/~jeff0124

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