Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
Folie 2 © Fraunhofer UMSICHT
Combination of coal-to-liquid plants with renewable hydrogen – electricity grid stabilization and efficient liquid storage
Tim Schulzke, Group Manager Thermochemical Processes and Hydrocarbons Dr. Christoph Unger, Think Tank Energy
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
Folie 5 © Fraunhofer UMSICHT
General applications for synthesis gas from lignite
lignite
gaseous fuel
thermal processes like ovens / kilns for calcination, dryling, melting, s intering etc.)
gas fired (steam) boilers
power generation with gas engines or gas turbines
incre
asin
g d
em
an
d o
n g
as u
pg
rad
ing
gasification solid fuel gas utilization / application
power generation with fuel cells
Syntheses (SNG or BtL) Impurities: dust, tars, sulfur, chlorine, …
Folie 6 © Fraunhofer UMSICHT
Synthesis reactions
Methane CO + 3 H2 ⇄ CH4 + H2O RH=-206 kJ/mol (3:1)
Fischer-Tropsch-Synthesis n CO + 2n H2 ⇄ (-CH2-)n + n H2O RH=-158 kJ/mol (2:1)
Methanol CO + 2 H2 ⇄ CH3OH RH=-98,7 kJ/mol (2:1)
Ethanol 2 CO + 4 H2 ⇄ C2H5OH + H2O RH=-256 kJ/mol (2:1)
Dimethyl Ether 2 CO + 4 H2 ⇄ H3C-O-CH3 +H2O RH=-219 kJ/mol (2:1)
Methane 2 CO + 2 H2 ⇄ CH4 + CO2 RH=-247 kJ/mol (1:1)
Ethanol 3 CO + 3 H2 ⇄ C2H5OH + CO2 RH=-297 kJ/mol (1:1)
Dimethyl Ether 3 CO + 3 H2 ⇄ H3C-O-CH3 + CO2 RH=-258 kJ/mol (1:1)
H2/CO-ratio in coal gasification: 1:2
(H2/CO)
Folie 7 © Fraunhofer UMSICHT
Exemplary process scheme: methanol
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Lignite
O2
CH3OH
Ele
ctr
icity G
rid
Pel
CO2
N2
Air
CO2
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
Folie 10 © Fraunhofer UMSICHT
Power-to-Liquids as negative controlling power fundamental challenges for Power-to-Liquids (PtL)
finding suitable CO2-sources
production from ambient air is possible, but very energy consuming
coal fired power stations with flue gas scrubbing (carbon capture)
anaerobic digestors (biogas plants) with upgrading to SNG
additional challenges for PtL as negative controlling power
CO2 at coal fired power stations not available in times with surplus electricity alternating operation of power station and PtL-plant
Synthesis reactor needs control range of 0 – 100 % today main difficulty either long start-up period (only long periods with surplus renewable electricity usable) or high energy loss for so-called „hot hold“ in idle mode
Folie 11 © Fraunhofer UMSICHT
Electricity demand and conversion efficiency
Water electrolysis
1 scm H2 needs 4.6 kWhel including losses
Methan synthesis
CO2 + 4 H2 ↔ CH4 + 2 H2O
9.3 kWhel / kg CO2, 363.64 g CH4 / kg CO2 = ̂ Hi=5.05 kWh max = 54.30 %
Methanol synthesis
CO2 + 3 H2 ↔ CH3OH + H2O
7.0 kWhel / kg CO2, 727.27 g CH3OH / kg CO2 = ̂ Hi=4.02 kWh max = 57.43 %
without energetic effort for CO2 supply, without chemical conversion losses!
Folie 12 © Fraunhofer UMSICHT
Exemplary process scheme: methanol
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2
H2
CH3OH
Ele
ctr
icity G
rid
Pel
CO2
Water CO2
Option I: CO2 + 3 H2 ↔ CH3OH + H2O
Option II: CO2 + H2 ↔ CO + H2O
CO + 2 H2 ↔ CH3OH
Control Range
0 – 100 %
in Germany: largest installation at biogas plant : 6 MWel
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
Folie 14 © Fraunhofer UMSICHT
Theoretical stoichiometry for synthesis gas products
lignite composition: 66 % C, 5 % H, 28 % O CH0.91O0.318
oxygen gasification (autotherm)
CH0.91O0.318 + 0.6135 O2 ↔ 0.2275 CH4 + 0.7725 CO2 Methan
CH0.91O0.318 + 0.72725 O2 ↔ 0.2275 CH3OH + 0.7725 CO2 Methanol
CH0.91O0.318 + 0.76516 O2 ↔ 0.1516 C2H6O + 0.8483 CO2 Ethanol/DME
steam gasification (allotherm)
CH0.91O0.318 + 0.9696 H2O ↔ 0.7123 CH3OH + 0.2876 CO2
requires external energy supply, in biomass gasification usually by combustion
yields additional CO2 in separate gas stream; good for stand alone CtL-plant
but overall carbon balance remains the same
autothermal gasification with steam moderated temperature control
CH0.91O0.318 + 0.443 O2 + 0.379 H2O ↔ 0.417 CH3OH + 0.583 CO2
_ _ _
_ _ _
Folie 15 © Fraunhofer UMSICHT
Example: Berrenrath HTW-gasifier (demoplant)
Outline data
Capacity: 27 t/h lignite
autothermal steam/oxygen gasification, HT-Winkler-gasifier, 123 MWth
Maximum product quantity: 12.5 t/h Methanol (300 t/d)
Minimum byproduct: 24 t/h CO2 (576 t/d)
Potential
complete conversion of CO2 requires electrolyzer with 168 MWel
complete conversion of CO2 produces 17.5 t/h Methanol (420 t/d)
Folie 16 © Fraunhofer UMSICHT
Exemplary process scheme: methanol
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2 Storage
Lignite
O2
O2
O2
H2
CH3OH
Ele
ctr
icity G
rid
Pel
Pel
CO2
Water
N2
Air
CO2
Control Range
50 – 100 %
CtL
PtL
Steam
Folie 17 © Fraunhofer UMSICHT
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2 Storage
Lignite O2
CH3OH
Ele
ctr
icity G
rid
Pel
CO2
N2
Air
CO2
Nominal Load
50 %
Steam
Operating status: no surplus electricity
Folie 18 © Fraunhofer UMSICHT
Operating status: surplus electricity available
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2 Storage
Lignite O2
O2
H2
CH3OH
Ele
ctr
icity G
rid
Pel
Pel
CO2
Water
N2
Air
CO2
Load
up to 100 %
Steam
Folie 19 © Fraunhofer UMSICHT
Operating status: increased electricity demand in grid
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2 Storage
Lignite
O2
O2
CH3OH
Ele
ctr
icity G
rid
Pel
CO2
N2
Air
CO2
Nominal Load
50 %
Steam
Folie 20 © Fraunhofer UMSICHT
Synergies through combination of CtL and PtL
Synergies
costs of PtL are dominated by electrolyzer only slight saving through cheaper reactor volume
omission of a dedicated CO2 supply reduces energy demand increased conversion efficiency of PtL process chain
synthesis reactor for PtL needs no control range from 0 – 100 % substantial improvement of operating control shortened start-up time, thus shorter periods with surplus renewable electricity usable, higher annual operating hours for electrolyzer substantial reduction of idle losses
increase of profitableness of the synthesis plant by use of electrolysis by-product O2
even offering positive controlling power is possible by dedicated derating of air separation unit
increase of carbon efficiency of the synthesis plant during feeding of additional hydrogen
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
Folie 22 © Fraunhofer UMSICHT
Research Demand: Ideal Injection point for Hydrogen
Gas Cleaning
Gas Conditioning
Methanol Reactor
CH3OH
CO2
H2
Reverse Water Gas Shift
CO2+ H2 CO + H2O
O2
Lignite
Steam
Folie 23 © Fraunhofer UMSICHT
Research Demand: Ideal Injection point for Hydrogen
Gas Conditioning
Methanol Reactor
CH3OH
H2
Reverse Water Gas Shift
CO2+ H2 CO + H2O
RWGS Reactor H2
H2
Tar Reforming Sulfur Removal CO2 Removal
CO2
O2
Lignite
Steam
Folie 24 © Fraunhofer UMSICHT
Research Demand
optimal feeding point for additional hydrogen
feeding into freeboard of gasifier partially or completely?
combined with recycle of CO2 as gasifying agent to the gasifier?
reverse water gas shift reactor between gasifier and CO2 removal partially or completely?
feeding into methanol reactor CO2-tolerant catalyst?
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Outlook
6. Summary
Folie 26 © Fraunhofer UMSICHT
Outlook
source: JB. Hansen, IEA Bioenergy Conference, Berlin, 2015
PEM / Alkali electrolysis: SOEC (at 500 °C) 4.6 kWh / scm H2 3.2 kWh / scm H2
Folie 27 © Fraunhofer UMSICHT
Outlook
Air Separation Unit
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
Electrolyzer
O2 Storage
Lignite
O2
O2
O2
H2
CH3OH
Ele
ctr
icity G
rid
Pel
Pel
CO2
Water
N2
Air
CO2
Control Range
50 – 100 %
Steam
PEM / Alkali electrolysis: 4.6 kWh / scm H2
SOEC (at 500 °C): 3.2 kWh / scm H2
Folie 28 © Fraunhofer UMSICHT
Outlook
Gasifier
Gas Conditioning
Gas Cleaning
Methanol Reactor
Product Separation
Methanol Storage
SOEC
Lignite
O2
H2
CH3OH
Ele
ctr
icity G
rid
Pel
CO2
Steam CO2
whole system: Control Range 50 – 100 %
Steam
PEM / Alkali electrolysis: 4.6 kWh / scm H2
SOEC (at 500 °C): 3.2 kWh / scm H2
© Fraunhofer
Outline
1. Coal Gasification to produce Gases or Liquids (CtG / CtL)
2. Fundamentals of Power-to-Liquids Technologies (PtL)
3. Synergies from the Combination of Synthesis Chemistry and PtL
4. Future Research Demand
5. Summary
Folie 30 © Fraunhofer UMSICHT
Summary
Combination of lignite-based synthesis plant with PtL
increases carbon efficiency of synthesis plant
improves operating control of PtL plant
offers controlling power in a scale relevant for transmission grid Example Berrenrath up to 168 MW negative controlling power by electrolyzer ( 4 MW positive controlling power by derating of air separation unit)
research demand identified for development of optimized strategy for hydrogen feeding
with development of SOEC technology and high availability of renewable electricity further efficiency improvement is possible in future
Folie 31 © Fraunhofer UMSICHT
Fraunhofer UMSICHT Department Biorefinery & Biofuels
Фотография: photocase.de
Thank You for Your kind attention!
Contact: Fraunhofer UMSICHT Osterfelder Strasse 3, 46047 Oberhausen, Germany E-Mail: [email protected] Internet: http://www.umsicht.fraunhofer.de/en
Dipl.-Ing. Tim Schulzke Telephone: +49 208 8598 1155 E-Mail: [email protected]