Wood Calorific Value vs Moisture Content
Wood Calorific Value vs Moisture Content
(OP)
Hi, i'm trying to get my hands on either a graph or an equation linking the moisture content of wood to its calorific value (kJ/kg) other units are fine though...
Most sources seem to say "if your wood is 30% is approximately xx" but its for a model so i actually need to know the variation.
Would be great if anyone has a source I haven't managed to find...
Thanks for any help in advance.
Most sources seem to say "if your wood is 30% is approximately xx" but its for a model so i actually need to know the variation.
Would be great if anyone has a source I haven't managed to find...
Thanks for any help in advance.





RE: Wood Calorific Value vs Moisture Content
http://www.epa.gov/burnwise/workshop2011/WoodCombu...
Go to page 22 for a graph on the effect of moisture content (MC).
RE: Wood Calorific Value vs Moisture Content
http://www.biomassenergycentre.org.uk/portal/page?...
RE: Wood Calorific Value vs Moisture Content
Vbottle 28, What kind of wood are we talking about? I have burned lots of Southern Pine bark & sawdust in boilers that was under the best conditions ~50% moisture. You could typically grab a handfull of the pure sawdust and squeeze it real hard and water would run out of it between your fingers. The softwood calorific value was considered to be 4500 B/lb. Then on some days it rained and the moisture content was even higher. And some wood was stored "under water" which meant that there were contstant spraying by sprinklers that distributed water across the entire stack of logs continually to keep the insects at bay. (Engineered a few of those systems too.) The calorific value of hardwood wasn't quite so high, but the moisture content was typically lower, but not by much. Rather burn the pine than the hardwood.
The link by 25362 on slide 21 says some wood can be up to 150% water. That's a puzzler. That would be almost like sponge wood.
What the article says about much of the calorific value of wood going to dry the wood so it would burn is real, so pay attention to your moisture content.
rmw
RE: Wood Calorific Value vs Moisture Content
rmw, from what i've found out so far, the calorific value of wood is pretty consistent, at least softwoods are consistent and hardwoods are, not exactly the same but close enough for my simple model. I'm going to be doing real tests and checking the moisture content before i burn and so i just need to be able to enter the m.c. value into my model for comparison.
Thanks guys :)
RE: Wood Calorific Value vs Moisture Content
The xls spreadsheet in the link above gives the net calorific value (GJ/t) of some woods vs moisture content up to 65 %, and I thought you were looking for something like this.
RE: Wood Calorific Value vs Moisture Content
Just a clarification for those who might not be familiar with the moisture content percentages:
The EPA paper (25362) quotes the dry-wood basis percent of moisture, so it can be greater than 100 percent.
The nice spreadsheets from ione quote the wet-wood basis moisture content, so it's always less than 100 percent.
Best to you,
Goober Dave
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RE: Wood Calorific Value vs Moisture Content
Why would water spray keep off insects from pine?
Seems like it would encourage infestation.
RE: Wood Calorific Value vs Moisture Content
RE: Wood Calorific Value vs Moisture Content
Mr. Cook, I don't know, and I like you have always been baffled by that process, but if you have lived in the deep south, passing any kind of storage yard containing southern pine one would witness huge sprinkler systems wetting all the wood in storage.
I guess you'd have to go to the pulp & paper forum to see if anyone there knows the answer.
For me, it meant some revenue designing the pumping and piping systems needed to sprinkle the logs. Fairly easy work, and lucrative too, because they had to be dependable. If they broke down, the bug attack started, don't you know.
rmw
RE: Wood Calorific Value vs Moisture Content
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RE: Wood Calorific Value vs Moisture Content
RE: Wood Calorific Value vs Moisture Content
On the other hand, logs at chip mills - places where logs were debarked and chipped and the bark and chips were shipped to distant pulp mills separately, the logs were stored 'under water' at times.
Trying to burn bark from logs stored 'under water' was almost mission impossible.
Someone who really knows the reason why may happen up on this and tell us. Or, I could try to get a call through to some of my old clients, problem being that they are really getting old now.
rmw
RE: Wood Calorific Value vs Moisture Content
rmw
RE: Wood Calorific Value vs Moisture Content
http://openagricola.nal.usda.gov/Record/IND2046242...