Foaming in full-scale biogas plants

Photo: André Künzelmann, UFZ
Estimation of the foaming propensity of substrates
in anaerobic digestion
Dr.-Ing. Lucie Moeller, Prof. Dr.-Ing. Andreas Zehnsdorf
Leipzig, 18th March 2015
Foaming in full-scale biogas plants
» 12 of 15 biogas plants that utilize biogenic waste
(own survey in Saxony, Saxony-Anhalt and Thuringia; Moeller et al. 2015)
» 5 of 36 biogas plants that utilize renewables in Saxony
(survey by Saxon State Ministry for Environment and Agriculture; 2012)
» 10% of biogas plants according to estimates by
7 biogas experts in Baden-Württemberg
(survey conducted by the University of Hohenheim; Wissmann 2014)
» 15 of 16 agricultural biogas plants in Denmark
(survey conducted by the Technical University of Denmark;
Kougias et al. 2013)
Page 2
Consequences of foaming
in biogas reactors
Process upsets and/or damage
à Clogging the gas pipes
à Disturbance of measuring probes
à Structural damage
Economic consequences
à Cleaning and repair costs
à Additional working hours
à Cost of defoamers
à Energy loss and/or overheads
Page 3
Foaming causes
in biogas reactors treating
a) biogenic waste
Page 4
b) renewables
Foaming causes
in biogas reactors
1. Unsuitable process management and unfavorable circumstances
à Substrate management (organic overload, nutrient deficiency)
à Process management (sudden temperature changes,
unsuitable agitation regime)
2. Use of risky substrates
à High in polysaccharides (rye, sugar beet)
à Small particles
à Filamentous microorganisms (Microthrix parvicella)
Page 5
Measures against foaming
in biogas reactors
à Starvation diet
à Optimization of process parameters
(feeding cycle, agitation cycles, etc.)
à Addition of plant oils and other
defoamers
à Supplementation with trace elements
“A clever person solves a problem.
A wise person avoids it.”
(Albert Einstein)
Page 6
Photo: www.ritter-sport.de
à High in protein (clover, alfalfa, yeast, animal blood)
Measures against foaming
in biogas reactors
Active Digestate
Substrate
to be tested
Photo: André Künzelmann, UFZ
Moeller, L., Zehnsdorf, A., Beyer, D. (2013) Testset
zur Bestimmung der Schaumneigung von Substrat
für Biogasanlagen. Gebrauchsmuster DE 202013000693 U1.
Page 7
Why to use a foam tester?
Dependence of the foaming intensity of the grain milling stage
0.5 mm
1 mm
2 mm
4 mm
Grain
Control
Digestate from an AD plant utilizing renewables mixed with coarse triticale (0.5 mm, 1 mm, 2 mm and 4 mm) and -grain
Moeller, L., Krieg, F., Zehnsdorf, A. (2013) Wirkung von Getreideschrot auf die Schaumbildung in Biogasanlagen.
Landtechnik 68 (5) 344-348.
Moeller, L., Goersch, K., Neuhaus, J., Zehnsdorf, A., Mueller, R.A. (2012) Comparative review of foam formation in
biogas plants and ruminant bloat. Energy, Sustainability and Society 2:12.
Page 8
Why to use a foam tester?
71 mPa*s
5.4 % DM
1.170 mPa*s
8.3 % DM
616 mPa*s
6.8 % DM
Moeller, L.: LEIPZIGER SCHAUMTESTER – Testset und dessen Verwendung zur Bestimmung der Schaumneigung
von Substrat für Biogasanlagen. Tagungsband des 6. Innovationskongresses BIOGAS 2013 „Effizienzsteigerung von
Biogasanlagen“ in Osnabrück, S. 151-156.
Moeller, L., Eismann, F., Wißmann, D., Nägele, H.-J., Zielonka, S., Müller, R.A., Zehnsdorf, A.: Innovative test method
for the estimation of the foaming tendency of substrates for biogas plants. Waste Management. submitted
Page 9
Why use a foam tester?
37 °C
Room temperature
Moeller, L.: LEIPZIGER SCHAUMTESTER – Testset und dessen Verwendung zur Bestimmung der Schaumneigung
von Substrat für Biogasanlagen. Tagungsband des 6. Innovationskongresses BIOGAS 2013 „Effizienzsteigerung von
Biogasanlagen“ in Osnabrück, S. 151-156.
Moeller, L., Eismann, F., Wißmann, D., Nägele, H.-J., Zielonka, S., Müller, R.A., Zehnsdorf, A.: Innovative test method
for the estimation of the foaming tendency of substrates for biogas plants. Waste Management.
Page 10
Development of a testing tool for on-site investigations
Requirements:
1. Maintaining a constant temperature of up to 60 ° C for several hours
Thermophilic range
42
60
60
38
55
55
34
50
50
30
Versuch 1
26
Versuch 2
Versuch 3
22
Versuch 4
45
Temperatur [°C]
Temperatur [°C]
Temperatur [°C]
Mesophilic range
Versuch 3
40
Versuch 4
Sollwert (55 °C)
45
Versuch 1
40
Versuch 2
Sollwert (57 °C)
35
35
30
30
25
25
Sollwert (37 °C)
18
14
0
1
2
3
4
Zeit [h]
(37 +/- 0.29) °C
5
6
20
20
0
1
2
3
Zeit [h]
4
5
6
0
1
2
3
4
5
6
Zeit [h]
(55 +/- 0.09) °C
Page 11
Development of a testing tool for on-site investigations
Requirements:
2. Simple handling
3. Robustness
for use under field conditions
Photo: André Künzelmann, UFZ
Page 12
Development of a testing tool for on-site investigations
Requirements:
4. Safety during handling and prevention of explosions
Page 13
Substrate
loading
Mixing
START
t= 3h
t= 6h
I Q I N N O VATI O N SPREI S LEI PZI G 2 0 1 4
Page 15
What is the innovation?
- the first test kit for determining the foaming tendency of substrates in
biogas plants worldwide
- enables: - the detection of critical substrates before the use
- the diagnosis of foaming causes in biogas plants
- the optimization in safe test mode
- makes visual experience, what will happen in the biogas reactor
The LEIPZIG FOAM TESTER increases the competitiveness of plant
operators by optimal use of problematic substrates.
Page 16
Photo: UIT Dresden, GmbH
Photo: André Künzelmann, UFZ
Page 17
Application of foaming tests for
research of foam control options
Page 18
Foaming depends on the particle size
0.5 mm
0.5 mm
1 mm
2 mm
2 mm
4 mm
4 mm
unground
Grain
Control
Digestate from an AD plant utilizing renewables mixed with coarse triticale and grain
Moeller, L., Krieg, F., Zehnsdorf, A. (2013) Wirkung von Getreideschrot auf die Schaumbildung in Biogasanlagen.
Landtechnik 68 (5) 344-348.
Moeller, L., Goersch, K., Neuhaus, J., Zehnsdorf, A., Mueller, R.A. (2012) Comparativ review of foam formation in
biogas plants and ruminant bloat. Energy,Sustainability and Society 2:12.
Moeller, L., Krieg, F., Zehnsdorf, A. (2015) Foaming in biogas plants as a result of
coarse grain anaerobic digestion. In prep.
Page 19
Foaming can be minimized by addition of plant oil
Moeller, L., Krieg, F., Zehnsdorf, A. (2015) Foaming in biogas plants as a result of coarse grain anaerobic digestion. In prep.
Page 20
Foaming depends on chemicals in manure
Foam content:
(= Foam height vs. overall height) [%]
70%
62%
0%
0%
Control
Dolomitic
lime
Sugar beet
silage
Sugar beet
silage +
dolomitic lime
Moeller, L., Lehnig, M., Schenk, J., Zehnsdorf, A.: Foam formation in biogas plants caused
by anaerobic digestion of sugar beet. Bioresource Technology 2015, 178, 270-277.
Page 21
Foaming depends on C/N ratio in digestate
89%
71%
0%
Control
0%
Urea
Sugar beet silage
Moeller, L., Lehnig, M., Schenk, J., Zehnsdorf, A.: Foam formation in biogas plants caused
by anaerobic digestion of sugar beet. Bioresource Technology 2015, 178, 270-277.
Page 22
Sugar beet silage + urea
If you want to learn more…
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Take home messages:
Ø
Foaming in the process of anaerobic
digestion is a common phenomenon
Ø
Foam in biogas plants is a result of:
- Unsuitable process management
- The use of risky substrates
Ø
LEIPZIG FOAM TESTER helps
- to evaluate the foaming propensity
of substrates on-site
- to diagnose foaming causes
- to develop foam control options
Page 24
Photo: André Künzelmann, UFZ
Thanks to…
Ø Operators of biogas plants
Ø Working group “Bioprozesstechnik”
Ø Frank Eismann (Eismann & Stöbe GbR)
Photo: André Künzelmann, UFZ
Ø Umwelt- und Ingenieurtechnik GmbH Dresden
Photo: UIT Dresden GmbH
Ø BMU (funding programme „Biomass energy use“)
and Initiative and Networking Fund of Helmholtz Association
Page 25

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