Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Wood and Bio Mass - Combustion Heat

Combustion heat values for wet and dry wood - Btu/pounds, kJ/kg and kcal/kg.

Sponsored Links

In the laboratory it is possible to get a heat value of 8660 Btu/lb from wood fuel. This "high heat value" is obtained only with perfectly dry wood with 0% moisture content and in an atmosphere of pure oxygen. For laboratory use this is a useful number handy for theoretical problem analysis. But for the practical world it is unrealistic.

When wood is alive and fresh it consists primarily of water, i.e. most of the weight is actually water. After being cut to length and stacked for a year or two the average moisture content generally drops to approximately 20%.

In the combustion process water is evaporated and the temperature is raised to flue gas temperature.

Condition of WoodApproximate Combustion Values
btu/lbkJ/kgkcal/kg
Wet 4000 9300 2220
Dry 7000 16300 3890
  • 6.3 lbs dry wood = 1 Boiler Horse Power
  • 11.6 lbs wet wood = 1 Boiler Horse Power

Moisture Content and Usable Energy

Moisture Content and Usable Energy
Moisture Content
%
Energy by Volume Unit
%
Energy per Weight Unit
%
0 (oven dry) 100 100
20 (air-dry) 97 81
50 (green) 92 62
100 (wet) 85 42

Note that

  • by volume wet wood has about 85% of the energy of oven-dry wood
  • by weight wet wood has less than half -  42% - of the energy of oven-dry wood

One weight unit of wood has enough energy to evaporate 6 weight units of water.

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

3 30

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more