Irini Angelidaki, Kanokwan Boe
and Lars Ellegaard
Presentation content
• Biogas in Denmark: A typical Centralized Biogas Plant
• Main Results of the investigation
• Conclusions
Location of Centralized biogas plants in Denmark
Typical centralized biogas plant
Ribe biogas plant
Full-scale investigation
 Process stability
 Process efficiency
 Microbiology
Potential methods to improve recovery
efficiency from manure
- Increase stabilily of the digestion process
- Pre-treatment of incoming substrate (to increase
degradability)
- Increase retention time of the manure reactor(s)
- Arrange post-digestion systems (to increase
degradation efficiency)
Stability in Danish Biogas Plants
14
12
Total VFA (g/L)
10
8
6
4
2
0
Apr-02 Jun-02 Aug-02 Oct-02 Dec-02 Jan-03 Apr-03 Jun-03 Aug-03 Oct-03
Date
Blaabjerg
Blaahoej
Fangel
Farsø
Filskov
Grindsted
Hashøj
Lemvig
Lintrup
Nysted
Revninge
Sinding-Oerre
Snertinge
Studsgaard
Thorsø I
Vaarst-Fjellerad I
Vegger I
Århus I
VFA, g/L
Correlation between ammonia and VFA.
8
7
6
5
4
3
2
1
0
0
2
4
Ammonium, g/L
6
8
Residual methane production
55oC
25oC
20oC
15oC
55oC
55oC
25oC
20oC
15oC
Residual methane production
7
ml-CH4/ml-sample
6
5
55 oC
4
25 oC
20 oC
3
15 oC
2
1
0
0
20
40
60
Time (days)
80
100
Ve
st
er Si n
di
n
År Hj.
hu Fe g
b
s
m -04
Bl
åb ma
Sn je r r-04
e r g ju
ti n
ng
N e f 03
ys
e
te b -0
d
m 4
H
as ar-0
Le hø 4
m j ju
v
l
R
ev ig m .03
ni
ng ar0
Li e m 3
n
a
Va tru p r-0
4
ar
s t aug
-0
Fj
.
Th M 3
or a rsø 04
f
Bl
åh eb0
Ve øj m 4
gg a
r-0
e
Fa r fe 4
St ng b-0
4
u d el
sg feb
å
-0
4
År rd f
hu eb
s
t m o4
Fi
l s arko
04
v
ok
t-0
3
Metan (m3/m3-biomasse)
Residual methane production
Sluttab - metan
tab
12
10
8
6
4
2
0
Bl
å
Ve bje
st rg j
er
u
H n-0
j.
Fe 3
År
bhu
0
s
sa Si 4
nd
m
in
Sn let
er m g
ti n ar
ge -04
Th
fe
or b 0
s
N ø fe 4
ys
te b-0
d
4
Li
m
nt
ar
ru
-0
p
4
a
ug
H
as
-0
Le høj 3
m
j
vi u l.0
g
Fa m 3
ng arR
03
ev el
f
e
ni
ng b-0
e
4
Bl ma
Va åhø r-0
ar j m 4
st
ar
Fj
-0
Ve . M 4
gg ar
-0
St
4
u d er
sg feb
år
d 04
Fi feb
ls
ko -04
v
ok
t-0
3
%
Restgastab i forhold til total
produktion
Tab i forhold til praktisk opnåelig produktion
30
>15%
10-15%
Termofil
Mesofil
Term+mes
25
20
15
10
5
0
< 10%
ju
n03
Sn
S
er
ti n i ndi
ng
ge
Th
fe
b
or
sø -04
Li
fe
nt
bru
04
p
Le
au
m
gvi
03
g
m
Bl
ar
å
-0
Va hø
3
j
ar
m
st
ar
-0
Fj
.
M 4
Ve
g g a r04
St
e
ud r f
sg eb04
år
d
fe
Fi
b
ls
k o -04
Ve
v
st
ok
er
t-0
H
j.
Fe 3
N
ys
te b-0
4
d
m
H
as ar-0
4
h
Fa øj ju
ng
l.0
R
3
ev el f
e
ni
ng b-0
4
e
m
ar
-0
4
Bl
åb
je
rg
%
Temperature and residual methane
Tab i forhold til praktisk opnåelig produktion
Termofil
Mesofil
30
25
20
15
10
5
0
Distribution of the total methane
potential
OPTIMAL TOTAL CH4 PRODUCTION
70
m3-CH4/m3-Bio
60
50
40
30
20
10
0
e
gg
Ve
r
H
h
as
j.
tF
øj
V
rs
aa
Ve
er
st
H
j.
ga
ut
St
rd
Reactor production (on the bottom)
d
te
N
ys
R
ni
ev
e
ng
øj
åh
l
B
S
ng
rt i
e
n
v
ko
e
ls
Fi
B
bj
la
g
er
n
Fa
l
ge
ru
nt
Li
p
ug
-a
-0
2
ru
nt
Li
After-Storage production (in the middle)
p
ug
-a
-0
3
ru
nt
Li
ja
p-
n-
03
R
e
ib
ø
o
Th
rs
Lost production (on the top)
Main reactor residual methane loss
versus retention time
35
% restidual loss
30
25
20
15
10
5
0
0
5
10
15
HRT (days)
Mesophilic plants
20
25
Thermophilic plant
30
Relative overall activity
Temperature effect on residual biogas
potential
120%
100%
80%
60%
40%
20%
0%
0
10
40
30
20
Post digestion temperature (oC)
Thermophilic
Mesophilic
50
60
Model curve Thermophilic
Model curve Mesophilic
INCREASING TEMPERATURE
Samples previously incubated at 10 -15C for a long period have been
moved to process temperature (37-54C):
Studsgård (R)
Revninge
8
7
m3 CH4/m3 Bio
m3-CH4/ m3-Bio
9
9
8
7
6
5
4
3
2
1
0
6
5
4
3
2
1
0
0
20
40
60
80
100
120
Time (d)
Spec. Prod. At 10 C
Spec. Prod at 37 C
Spec. Prod from 10 cto 37 C
140
160
0
10
20
30
40
50
60
70
80
90
Time (d)
Spec. Prod. at 54 C
Spec. Prod at 15 C
Spec. Prod from 15 C to 37 C
spec. Perod from 15C to 54C
100
INNOVATIVE SOLUTIONS
SITUATION:
•The majority of the biogas plants have Reactors with good efficiency;
•Many plants are loosing a lot and the gap between the theoretical and the
practical potential is still wide;
MAIN OBSTACLE: hydrolysis is the real rate limiting step for the further
methanogenesis  increase HRT to provide a better substrate hydrolysis
SOLUTIONS:
TRADITIONAL
SOLUTIONS
INNOVATIVE
SOLUTIONS
Increase the HRT in main reactor
New process configurataion:
Utilization of the After-Storage.
Conclusions
• Significant amounts of CH4 are lost (5-30%)
• Plants with HRT< 15 days are lossing more CH4 from the
main reactor
• Post-digestion is highly influenced by the temperature
• Post-digestion at low temperature are increasing the total
methane potential of the material
• Manure-plants are dominated by Methanosarcina, while
sludge plants by Methanosaeta.
Acknowledgements
 The study was funded by the Danish Energy Agency,“Development of Renewable
Energy”
 The operational staff of the Biogas Plants participating in the investigation is greatly
acknowledged
 Researchers:





Kanokwan Boe
Lars Ellegaard
Dimitar Karakshlev
Damien Batstone
Irini Angelidaki
 Students:







Simone Labo
Lucía Fernández García
Eva Arler
He Zhen
Chao Pan
Troels Hilstrøm
Søren H. Laursen
 Technicians:
 Hector Garcia
 Majbrit Staun Jensen