Environmental Engineering Reference
In-Depth Information
Fermentation products
Substrate & Fermentation process
Fermentation
temperature
Bio-gas
mmol/g cellulose
By-
products
CSTR
Mesophilic
37
±
2
℃
0.6
H
2
+ 7.1
CH
4
Active Volume
6L
HRT
10d
pH
5
ʙ
6
VFA
Lactic
acid
Ethanol
and
others
Substrate tank
Thermophilic
55
±
2
℃
15.2
H
2
Carbon
source
5g/L Cellulose
Macronutrients
Micronutrients
Hyper-thermophilic
80
±
2
℃
19.01
H
2
Photo-fermentation
and two-phase process
Sludge
Fig. 8.6
Continuous cellulosic dark hydrogen production under different fermentation tempera-
ture. (Gadow et al.
2012
)
Cellulose
Complex molecules
Cellulose
Complex molecules
Cellulose
Complex molecules
Hydrolytic bacteria
Hydrolytic bacteria
Hydrolytic bacteria
yy
Glucose
Glucose
Glucose
Glucose
Fermentation
bacteria
n
Glucose
Glucose
Enterobacter
Enterobacter
Fermentation
bacteria
Fermentation
bacteria
En
Enterobacter
Clostridium
Fermentation
bacteria
Enterobacter
Butyrate
Butyrate
Butyrate
Clostridium
Butyrate
Butyrate
Syntrophs
Propionate
Syntrophs
Propionate
M
Morella
sp.
Ethanol
Ethanol
Ethanol
H
2
+ CO
2
H
2
+ CO
2
Acetate
Acetate
Acetate
Acetate
H
2
+ CO
2
Acetate
Acetate
Methanogens
Methanogens
CH
4
CH
4
H
2
+ CO
2
Thermophilic cellulosic
fermentation
Hyper-thermophilic cellulosic
fermentation
Mesophilic cellulosic
fermentation
Fig. 8.7
Effect of temperature on microbial community dynamics in cellulosic-hydrogen fermen-
tation. (Gadow et al.
2013
)
8.3.5
Stoichiometry of Hydrogen Production from Fermentation
of Cellulose
The stoichiometry equations of hydrogen production from fermentation of cellulose
in Fig.
8.7
are calculated as follows:
Mesophilic reactor
(
)
C H
O
→
1.28nCH
+
0.11nH
+
0.44nCH COOH
6
10
5
4
2
3
n
+
0.35nC H COOH
+
3.31nCO
+
others
(8.4)
3
7
2
