Environmental Engineering Reference
In-Depth Information
PNNL Pacific Northwest National Laboratory
SCGP Shell Coal Gasification Process
SCWG supercritical water gasification
SCW
supercritical water
SNG
substitute natural gas
TGA
thermogravimetric analysis
SYMBOLS
[m
2
]
A
area
[m
2
m
−3
]
a
s
specific surface area of a particle
[m
2
kg
−1
]
a
s,m
specific surface area (mass basis)
m
−3
]
c
i
concentration of species i
[mol
CC
carbon conversion
[
-
]
CGE
cold gas efficiency
[
-
]
[m
2
s
−1
]
D
binary diffusion coefficient
[m
2
s
−1
]
D
e
effective diffusion coefficient
[m
2
s
−1
]
D
i
intraparticle diffusion coefficient
d
diameter
[m]
mol
−1
]
E
a
activation energy
[J
mol
−1
]
Δ
r
H
reaction enthalpy (change)
[J
m
−2
K
−1
]
h
heat transfer coefficient
[W
[mol
2
m
−6
]
Kw
ion product of water
k
reaction rate coefficient
[depending on
order]
s
−1
]
k
g
mass transfer coefficient (gas phase)
[m
m
mass
[kg]
mol
−1
]
MW molecular weight
[kg
p
(partial) pressure
[Pa]
m
−3
s
−1
]
R
i
net production rate of species i
[mol
R
0
i
s
−1
]
net production rate per unit mass of solid particle
[mol
kg
solid
mol
−1
K
−1
]
R
u
universal gas constant (=8.3143)
[J
r
radius
[m]
SB
steam-to-biomass mass ratio
[
-
]
SB
∗
steam-to-biomass mass ratio including fuel moisture
[
-
]
T
temperature
[K]
t
time
[s]
X
(degree of ) conversion
[
-
]
Y
i
mass fraction of compound/element i
[
-
]
α
distribution coefficient for C-oxidation to CO/CO
2
[
-
]
ε
voidage
[
-
]
η
particle
'
s utilization factor in reactions
[
-
]
η
HE
heat exchanger efficiency
[
-
]
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