pdp1@EARTHLINK.NET on fri 10 sep 04
Hi Marcia, all...
The rule of thumb for BTUs and Woods, is that their heat
potential is on par with their spcific gravity; the heavier
the ('dry') Wood, the more potential Calories or BTUs it
will have to offer...
Thin sections will combust faster than thick sections, even
as paper, being thinner yet, will combust faster than the
thin sections...
While the overall possible Heat Values will be a factor of
mass or density, and not necessarily ostensible size or
section.
Phil
el ve
----- Original Message -----
From: "Marcia Selsor"
> Reading Craig's post made me think that I had not see the
original
> person mention their fuel..propane or natural gas.
> There is a whole different appraoch for natural gas
opposed to propane
> when it comes to the oriface size.
> I have made burners for propane and oil. When researching
the topic of
> oil I found some great info on sources of fuels and their
BTU
> capability.
> I even found a BTU rating for various woods. Elm was way
up there. But
> then again you can get a lot of BTUs out of wood if it ic
cut thin and
> burns fast. So there is a whole variety of possibilities
there too.
> Honestly, sometimes I think the more you know, the more
you don't know.
> Marcia Selsor
steve harrison on sun 12 sep 04
Hi Marcia,
Phil makes some very good points as usual.
I though that I might just add that nearly all woods have the same BTU=20=
rating per pound.
Heat Energy
There is suprisingly little difference in calorific value between=20
various timbers. Brown states, "The heat energy released by burning=20
forest fuels is high and does not vary widely between different types=20
of fuels."
The table below gives the heat values of some different types of =
fuels.
Heat of combustion
Substance for oven dry material, Btu/lb
Wood (oak) 8,316
Wood (beech) 8,591
Wood (pine) (type unspecified) 9,153
Wood (poplar) 7,834
Pine sawdust 9,347
Spruce sawdust 8,449
Wood shavings (type unspecified) 8,248
Pecan shells 8,893
Hemlock bark 8,753
*Pitch (source unspecified) 15,120
Average (*excluding pitch) 8,620
The content of the wood plays a part depending on the species.=20
According to Brown: =93The heat of combustion varies slightly for the=20
wood of different species. It is a little higher for a coniferous=20
species such as pine than for the hardwood species. This is a result of=20=
both the higher resinous content and higher lignin content of the=20
conifers=94.
I have written a book on wood firing here in Australia that explains=20
this and other aspects of wood firing.
Best wishes
Steve Harrison
Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia
http://ian.currie.to/sh/Steve_Harrisons_books.html
On Saturday, September 11, 2004, at 10:49 AM, pdp1@EARTHLINK.NET wrote:
> Hi Marcia, all...
>
>
> The rule of thumb for BTUs and Woods, is that their heat
> potential is on par with their spcific gravity; the heavier
> the ('dry') Wood, the more potential Calories or BTUs it
> will have to offer...
>
> Thin sections will combust faster than thick sections, even
> as paper, being thinner yet, will combust faster than the
> thin sections...
>
> While the overall possible Heat Values will be a factor of
> mass or density, and not necessarily ostensible size or
> section.
>
>
> Phil
> el ve
>
>
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