Proces imbalance in biogas plants. Henrik Bangsø Nielsen Biogasforum, seminar, 14/6-2006 Strategies...
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Transcript of Proces imbalance in biogas plants. Henrik Bangsø Nielsen Biogasforum, seminar, 14/6-2006 Strategies...
Proces imbalance in biogas plants.
Henrik Bangsø NielsenBiogasforum, seminar, 14/6-2006
Strategies for preventing breakdown and recoveryof the biogas process
Outline
Project strategy
Resume of last presentation (29-11-05)
Follow up on last presentationDigestion of blood (Lemvig biogas plant)
Ongoing experiments:Process recovery following ammonia and lipid inhibition
Comments from the audience ?
Visits at biogasplants
Data collection
Experiments and resultsthat can be 1) directly related and used by specific plants and 2) can
be published
A B
C
Overall project strategy
Main conclusions:
“No problems”
Pre-storage tanks are not useful
Substrate composition is unknown
Substrate degradation characteristics is unknown
Inadequate surveillance, especially with regard to VFA
A: Visits at biogas plants
B: Data collection
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
29-08-2002
28-10-2002
27-12-2002
25-02-2003
26-04-2003
25-06-2003
24-08-2003
23-10-2003
22-12-2003
20-02-2004
20-04-2004
19-06-2004
18-08-2004
17-10-2004
16-12-2004
14-02-2005
15-04-2005
date
met
han
e (m
3/m
3 re
acto
r vo
l.)
daily
10 per. Mov. Avg. (daily)
20 per. Mov. Avg. (daily)
Foaming starts april 2003 Foaming ends march 2005
C: Experiments and results
Pre-storage tanks are not useful: Plant constructors
Substrate composition is unknown and substrate degradation characeristics is unknown: E and R: Screening of various wastes with regard toxicity and biogas potential. Establishment of waste index.
Inadequate surveillance, especially with regard to VFA E and R: VFA surveillance and development of VFA sensors
Follow up on last presentation
Digestion of blood at Lemvig biogas plant
0
1
2
3
4
06-okt-05
13-okt-05
20-okt-05
27-okt-05
03-nov-05
10-nov-05
17-nov-05
24-nov-05
m3/
(m3
reac
tor v
ol.)
0
20
40
60
80
09-nov-05 14-nov-05 19-nov-05 24-nov-05
mM
Acetat Propionate Isobut. Butyrate Isoval. Valerate
Biogas production VFA concentration
Blood from pigs added from 1. of September 2005
Slow inhibition of biogas production observed in the beginning of October
Biogas production constituted only 40% of normal production at the 8. of november
Inhibition a combination of increasing pH and ammonia
Related experiments
Substrate characterization in batch
37 Degree
0
2
4
6
8
10
12
14
0 10 20 30 40 50
time (days)
pro
du
ctio
n (
ml
CH
4/m
l sa
mp
le)
0,5 g/l
1 g/l
5 g/l
10 g/l
55 Degree
0
2
4
6
8
10
12
14
0 10 20 30 40 50
time (days)
pro
du
ctio
n (
ml
CH
4/m
l sa
mp
le)
0,5 g/l
1 g/l
5 g/l
10 g/l
Degradation more effective at 37oC than at 55oC
Inhibition level at 37oC: between 0.5 and 1.0 g/l
Inhibition level at 55oC: < 0.5 g/l
Digestion at different temperatures in lab-scale reactors
Related experiments
37oC 55oC
0
50
100
150
t i me (days )
VFA
(m
M)
Total VFA
acetic
propionic
isobutyric
butyric
isovaleric
valeric
0
100
200
300
CH
4 yi
eld
(ml
CH
4/g
VS
)
0
10
20
30
40
biog
as p
rod.
(m
l /m
l fee
d)
7
7,2
7,4
7,6
7,8
8
8,2
pH
0,0
0,2
0,4
0,6
0,8
1,0
0 10 20 30 40 50 60 70 80 90 100 110
time (days)
free
am
mo
nia
(gN
/l)
0
50
100
150
200
250
300
CH
4 yi
eld
(ml C
H4/
g V
S)
0
10
20
30
40
bio
gas
pro
d.
(ml/
ml
feed
)
7
7,5
8
8,5
pH
0
50
100
150
VF
A (
mM
)
acetic
isobutyric
butyric
isovaleric
valeric
propionic
0,0
0,2
0,4
0,6
0,8
1,0
0 10 20 30 40 50 60 70 80 90 100
time (days)
free
am
mo
nia
(g
-N
/l)
Conclusions:Work at mesophilictemperatures or measureVFA frequently
Threshold value for the Thermophilic reactor was3.8 gN/l and 0.7-0.9 g freeAmmonia-N/l.
At mesophilic conditions itWas possible to work at an Ammonia concentration of 4.7 gN/l with a yield of 130Ml methane/g VS
VFA surveillance of the plant
0
10
20
30
40
50
60
70
80
90
1.8.05 20.9.05 9.11.05 29.12.05 17.2.06 8.4.06 28.5.06
dato
Ace
tat/
pro
pio
nat
(m
M)
0
1
2
3
4
5
6
7
8
To
tal
syre
(g
/l)
acetat Propionat Total syre Total syre
++++-+
Minkfedt+-
Related experiments
Related experiments
R1 biogas production
0
1000
2000
3000
4000
5000
0 20 40 60 80 100
mlbiogasR2 biogas production
0
1000
2000
3000
4000
5000
0 20 40 60 80 100
ml biogas
Reactor experiment with lipids
Day 60: 5% lipid (W/W) were added = 50% VS = no inhibitionDay 87: 25% lipid (w/w) were added = 85 VS = inhibition
Conclusion: plant added more lipid than allowed (25% TS)
Ongoing experiments
0,0
0,5
1,0
1,5
2,0
2,5
16-10-2001
15-12-2001
13-02-2002
14-04-2002
13-06-2002
12-08-2002
11-10-2002
10-12-2002
08-02-2003
09-04-2003
08-06-2003
07-08-2003
06-10-2003
05-12-2003
03-02-2004
03-04-2004
02-06-2004
01-08-2004
30-09-2004
29-11-2004
28-01-2005
29-03-2005
date
me
tha
ne
(m
3/m
3 r
ea
cto
r v
ol.
)
What now?
Recovery of the process following process imbalances
Recovery strategies
Stop feeding (the process recovers automatically).
Continued feeding with manure (addition of fresh substrate to keep up the biogas production)
Continued feeding with substrate adaptation will occur)
Re-inoculation with effluent (addition of new microorganisms)
Dilution with water (inhibiting compound is diluted)
Recovery of the biogas process
Set-up
Mixture
1: Inoculum
2: Manure
3: LCFA or ammonia at steady biogas production
Recovery of the biogas process
Long chain fatty acids inhibition
Identification of oleate inhibition level
0
100
200
300
400
500
600
0 10 20 30 40 50 60 70days
CH
4 (
mL
/gV
S)
control
oleate 3gVS/L
oleate 5gVS/L
oleate 7gVS/L
inoculum and oleate 3gVS/L
mixture + BA media + oleate 3gV/L
Oleateaddition
10
100
1000
Day 4 Day 7bef. Inhib
Inhib + 3Bef. Recov
Inhib + 7Recov + 4
Inhib + 13Recov + 10
Inhib + 21Recov + 18
Inhib + 31Recov + 28
ml C
H4/
gV
S in
itial
no inhib.
inhib no recov.
recov water dilution
recov.inoc dilution
recov manure dilution
1180
Recovery of the biogas process
Long chain fatty acids inhibition
Test of strategies
Recovery of the biogas process
Long chain fatty acids inhibition
Inhibition 5gVS oleate/L with different inoculum/manure ratio
0
100
200
300
400
500
600
4 7 10 14 20 28 38
ml C
H4/
gV
S
inoc 25/ man 15
inoc 11/ man 29
Inhibition
days
R1 TS/VS = 2.9/2.1%
0
100
200
300
400
500
100 110 120 130 140 150 160 170 180 190
met
hane
ml/g
VS
R2 TS/VS = 5.4/4.1%
0
100
200
300
400
500
100 110 120 130 140 150 160
met
hane
ml/g
VS
0.5 g/l 0.5 g/l1.0 g/l 1.0 g/l2.0 g/l 2.0 g/l
2.0 g/l
0
15
30
45
60
75
90
100 110 120 130 140 150 160
acet
ate
mM
0
5
10
15
20
25
30
prop
iona
te m
M
time (days)
0
15
3045
60
75
90
100 110 120 130 140 150 160 170 180 190
acet
ate
mM
0
5
1015
20
25
30
prop
iona
te m
M
time (days)
Pulses with oleate
Effect of TS/VS
Recovery of the biogas process
Long chain fatty acids inhibition
Conclusions:
Using one of the strategies could stimulate the recovery of the process
Following inhibition with LCFA, the recovery proceeded fastest whenthe biomass was diluted with manure.
The fast recovery with manure could be due to a higher concentration ofTS/VS (fibers)
However, what about reactor experiments!!!
Recovery of the biogas process
Ammonia inhibition
10
100
1000
Day 5 Day 9bef. Inhib
inhib+3 /bef. Recov
inhib+6 /recov+3
inhib+16 /recov+13
inhib+29 /recov+26
inhib+41 /recov+38
ml C
H4
/gV
S in
itia
l
no inhib. TN=3.0g/L
inhib. TN=7.0g/L
inhib+water dilution TN=3.5g/L
inhib+inoc dilution TN=5.2g/L
inhib+manure dil. TN=4.6g/L
inhib+pH decrease TN=7.0g/L
932Test of strategies
Prodution rates day 9 to 12Control: + 50 mlInhibition: + 26 ml
Recovery of the biogas process
Ammonia inhibition
Utilization of biogas potential
0
100
200
300
400
500
600
700
no inhibition inhibition norecov.
recov w ater recov inoc recov manure
ml C
H4
theorical level
experimental level
Effienciency as a function of N-content
70
75
80
85
90
95
100
105
110
2,5 3,5 4,5 5,5 6,5 7,5N content (gN/L)
effic
ien
cy %
w ater dil.manure dil.
inoculum dil.
no recovery
no inhibition
No inhibition
No recovery
Water dilution
Inoculum dilution
Manure dilution
% of theoretical level 96 74 92 77 99
Final N-content 3 7 3,5 5,2 4,6
Recovery of the biogas process
Ammonia inhibition
Conclusions:
The recovery of the biogas process following sn smmonis inhibition was strongly related to the ammonia concentration.
Addition of fresh manure gave the best recovery (lower ammonia concentration, fresh substrate)
However, what about reactor experiments!!!
Acknowledgements
Thanks to Sonia Guldener, Henar Meer de Soto and Elena Pueyo Abad forsharing their results.Thanks to Hector Garcia and Prasad L. Kaparaju for their technical assistanceThe work is supported by Energistyrelsens Energiforsknings-program (EFP-2005)
Thank you for your attention!!!!
Waste type Temperature Inhibition level
g VS/l = kg VS/tBlood from pigs 37oC 0,5-1,0
Blood from pigs 55oC <0,5
Shrimp sludge 37oC 1,0-5,0
Shrimp sludge 55oC 0,5-1,0
Meat and Bone meal 37oC 1,0-5,0
Meat and Bone meal 55oC 0,5-2,0
100% Fat, DAO 55oC <1,0
Flotations fedt, pigs 55oC 0,5-1,0
Bakery (mainly fat) 55oC 5,0-10,0
Flotationsfedt, pigs 55oC 5,0-10,0
Flotationsfedt, pigs 55oC 5,0-10,0
Limfedt (fat) 55oC 5,0-10,0
Food waste (fat) 55oC >10,0
Flotationsfedt, chickens
55oC >10,0
Waste index