Biomass Characteristics - Biomass Gasification, Pyrolysis and Torrefaction - page 70

TABLE 3.7 Specific Heat of Wood and Wood Char

Validity
( C) Reference Fuel Specific Heat in kJ/kg K

Ragland et al.
(1991)

Dry
wood

C p,dry 5 0.1031 0.003867T

1

Wet
wood

[(C p,dry 1 A, where

M dry is moisture fraction on dry basis, T in
K, and A

4.19M dry )/(1 M dry )]

1 1

(0.02355T 1.32 M 6.191)M dry

5

Ragland et al.
(1991) a

Wood
char

1.39 1 0.00036T 420 1720

Gupta, et al
(2003) b

Softwood 0.00546T 0.524 40 140

10 2 3 T 2 Char

from
softwood

0.0038 0.00598T 0.795 40 413

2 3 1

147 C Simpson and

Tenwolde
(1999) c

Wood C p,dry 5 0.1031 0.003867T 7

1

C p 5 (C p,dry 1 4.19M)/(1 0.01M) Ac, 7 147

1 1

where Ac M

5

10 2 4 T 10 2 4 M) ( 0.06191 2.36 1.33

2 1 3 3

Jenkins (1989),
p. 876

Various
wood

C p,dry 0.266 0.00116(T 273) 0 106 C

5 1 2

C p 5 4.19M wet , where

M wet is moisture fraction on wet basis

C p,dry (1 M wet ) 0 106

2 1

a Ragland, K.W., Aerts, D.J., Baker, A.J. (1991). Properties of wood for combustion analysis
Bioresource Technol. 37, 161 168.

b Gupta, M., Yang, J., Roy, C. (2003). Specific heat and thermal conductivity of softwood bark and
softwood char particles. Fuel 82, 919

927.
c Simpson, W., Tenwolde, A. (1999). Physical Properties and Moisture Relations of Wood
(Chapter 3) 3

17.

and Cl 2 are not compounds, and the heat of formation for them is zero. Values
for the heat of formation for common compounds are given in Table 3.8 .

3.5.2.4 Heat of Combustion (Reaction)
The heat of reaction (HR) is the amount of heat released or absorbed in a
chemical reaction with no change in temperature. In the context of combus-
tion reactions, HR is called heat of combustion,

Δ H comb , which can be calcu-

lated from the heat of formation (HF) as:
CH 4 1 2O 2 - 2H 2 O 1 CO 2 (3.14)