Transcript Process phase separation for methane enrichment

PROCESS PHASE SEPARATION FOR
METHANE ENRICHMENT
using microorganisms
abilities for biogas upgrading
Flensburg, 12.09.2013
Torsten Stefan, B.Sc. Bioprocess Eng.
2
Table of Contents
1.
2.
3.
4.
5.
6.
Motivation
Idea and Theory
Experiments
Results
Future aspects
Summary
3
Motivation
component
formula
heat of
combustion
[kJ/Nm³]
Typical
fraction in
biogas [%]
methane
CH4
39819
45-70
hydrogensulfide
H2S
25336
<0,5
ammonia
NH3
17177
<0,001
hydrogen
H2
12750
0-1
carbon dioxide
CO2
0
25-55
Water
H2O
0
0-10
4
Separation of CO2 and CH4 mixtures
• Water or polyglycol scrubbers
• Amine scrubbers
• Membrane systems
• Cryogenic processes
Economically feasable in large scale (>1 MWel)
5
Biogas process
Polymeric molecules
Hydrolysis
Monomers
Acidogenesis
CO2, H2
H2S, NH3,
N2
Volatile fatty
acids
Acetogenesis
CO2, H2
Formic/acetic acid,
CO2, H2
digestate
Methanogenesis
CO2, CH4
6
Hydrolysis
Pictures:chemienet.info
7
Acidogenesis
𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔
→ 𝐂𝐇𝟑 (𝐂𝐇𝟐 )𝟐 𝐂𝐎𝐎𝐇 + 𝟐 𝐇𝟐 + 𝟐 𝐂𝐎𝟐
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐛𝐮𝐭𝐲𝐫𝐢𝐜 𝐀𝐜
𝟑 𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔 → 𝟐 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝐂𝐇𝟑 𝐂𝐇𝟐 𝐂𝐎𝐎𝐇 + 𝟐 𝐇𝟐 𝐎 + 𝟐 𝐂𝐎𝟐
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐚𝐜𝐞𝐭𝐢𝐜 𝐀𝐜
𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔
𝐩𝐫𝐨𝐩𝐢𝐨𝐧𝐢𝐜 𝐀𝐜
→ 𝟐 𝐂𝐇𝟑 𝐂𝐇(𝐎𝐇)𝐂𝐎𝐎𝐇
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐥𝐚𝐜𝐭𝐢𝐜 𝐀𝐜
𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔
→ 𝟑 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐂𝟔 𝐇𝟏𝟐 𝐎𝟔
𝐬𝐮𝐠𝐚𝐫 𝐦𝐨𝐧𝐨𝐦𝐞𝐫
𝐚𝐜𝐞𝐭𝐢𝐜 𝐀𝐜
→ 𝟐 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝟒 𝐇𝟐 + 𝟐 𝐂𝐎𝟐
𝐚𝐜𝐞𝐭𝐢𝐜 𝐀𝐜
→ 𝟐 𝐂𝟐 𝐇𝟓 𝐎𝐇 + 𝟐 𝐂𝐎𝟐 + 𝟐 𝐇𝟐 𝐎
𝐞𝐭𝐡𝐚𝐧𝐨𝐥
8
Acetogenesis
𝑪𝟒 𝑯𝟗 𝑪𝑶𝑶𝑯 + 𝐂𝐎𝟐 + 𝟐 𝑯𝟐 𝑶 → 𝟑 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝐇𝟐
𝒊𝒔𝒐𝒗𝒂𝒍𝒆𝒓𝒊𝒄 𝑨𝒄
𝒂𝒄𝒆𝒕𝒊𝒄 𝑨𝒄
𝑪𝑯𝟑 (𝑪𝑯𝟐 )𝟐 𝑪𝑶𝑶𝑯 + 𝟐 𝑯𝟐 𝑶 → 𝟐 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝐇𝟐
𝒂𝒄𝒆𝒕𝒊𝒄 𝑨𝒄
𝒃𝒖𝒕𝒚𝒓𝒊𝒄 𝑨𝒄
𝑪𝑯𝟑 𝑪𝑯𝟐 𝑪𝑶𝑶𝑯 + 𝟐 𝑯𝟐 𝑶 → 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝟑 𝐇𝟐 + 𝐂𝐎𝟐
𝒑𝒓𝒐𝒑𝒊𝒐𝒏𝒊𝒄 𝑨𝒄
𝒂𝒄𝒆𝒕𝒊𝒄 𝑨𝒄
𝑪𝑯𝟑 𝑪𝑯(𝑶𝑯)𝑪𝑶𝑶𝑯 + 𝑯𝟐 𝑶 → 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝟐 𝐇𝟐 + 𝐂𝐎𝟐
𝒂𝒄𝒆𝒕𝒊𝒄 𝑨𝒄
𝒍𝒂𝒄𝒕𝒊𝒄 𝑨𝒄
𝑪𝟐 𝑯𝟓 𝑶𝑯 → 𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝐇𝟐
𝒆𝒕𝒉𝒂𝒏𝒐𝒍
𝒂𝒄𝒆𝒕𝒊𝒄 𝑨𝒄
9
Methanogenesis
𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 → 𝐂𝐇𝟒 + 𝐂𝐎𝟐
𝐂𝐇𝟑 𝐂𝐎𝐎𝐇 + 𝟐 𝐇𝟐 𝐎 → 𝟒 𝐇𝟐 + 𝟐 𝐂𝐎𝟐
𝐂𝐎𝟐 + 𝟒 𝐇𝟐 → 𝐂𝐇𝟒 + 𝐇𝟐 𝐎
𝟒 𝐇𝐂𝐎𝐎𝐇 → 𝐂𝐇𝟒 + 𝟑 𝐂𝐎𝟐 + 𝟐 𝐇𝟐 𝐎
𝒇𝒐𝒓𝒎𝒊𝒄 𝑨𝒄
𝟒 𝑪𝑯𝟑 𝑶𝑯 → 𝟑 𝐂𝐇𝟒 + 𝐂𝐎𝟐 + 𝟐 𝐇𝟐 𝐎
𝒎𝒆𝒕𝒉𝒂𝒏𝒐𝒍
10
Polymeric molecules
Biogas process
Gas Hydrolysis
composition
Intermediate
methane [%] Monomers
Carbon dioxide [%]
Formic acid
25
Acetic acid
50
75
Propionic acid
58,3
Butyric acid
62,5 Volatile fatty
41,7
acids
Valeric acid
65
Lactic acid
50
Ethanol
75
digestate
50
Acidogenesis
CO2, H2
H2S, NH3,
N2
37,5
35
Acetogenesis
Formic/acetic acid,
CO2, H2
Methanogenesis
50
CO2, H2
25
CO2, CH4
11
CO2 solubility in water
physical
chemical
CO2 solubility in water, 38°C
CO2 solubility in water, 38°C,
p(CO2)=0,3 bar
0.35
0.025
0.30
chem. Solubility [mol/L]
phy. Solubility [mol/L]
0.020
0.015
0.010
0.005
0.25
0.20
0.15
0.10
0.05
0.000
0.00
0
0.2
0.4
0.6
p(CO2) [bar]
0.8
1
3
4
5
6
pH [1]
7
8
9
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Biogas process
Polymeric molecules
Hydrolysis
Monomers
Acidogenesis
CO2, H2
H2S, NH3,
N2
Volatile fatty
acids
Acetogenesis
CO2, H2
Formic/acetic acid,
CO2, H2
digestate
Methanogenesis
CO2, CH4
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Experiments
14
Results
Substrate: Sugar-Cellulose-Mixture
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Results
Substrate: Sour cheese whey
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Results
Substrate: Pig-Manure
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Results from Literature
Substrate: Soybean Processing Wastewater
Resource: Zhu, G.F. ; Li, J.Z. ; Wu, P. ; Jin, H.Z. ; Wang, Z.: The performance and phase separated characteristics of an
anaerobic baffled reactor treating soybean protein processing wastewater. In:Bioresource technology 99 (2008), Nr. 17, S.
8027–8033
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Next steps
• Examine mixtures of manure and souring substrates
• Investigate semi-aerobic hydrolysis
• Upscaling to 200 L / 2 m³
• Proove applicability to STR cascades
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Summary
• Phase separation uses natural sequenced biogas process for
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methane enrichment
Methane fraction up to 85%
Relatively simple and cheap technology
Enhances energy storage capacity through higher methane
content
Applicable to STR cascades
Problems: slowly hydrolysible substrates and substrates with
high alkalinity in mono-fermentation