electrolysis assisted biomass gasification for biofuels
TRANSCRIPT
Electrolysis assisted biomassgasification for biofuels production- a technoeconomic perspective
Sennai Mesfun (RISE)Klas Engvall, Carina Lagergren (KTH)Andrea Toffolo (LTU)
Background
2
Biomass gasification-based biofuels
• Scalability of gasifier
• Multiple process steps
GasifierPrimary gas
cleaningReformer WGS
Final gas cleaning
SynthesisBiomass Transport fuel
steamO2/steam steam
CO2
Background
3
Electrolysis assisted biomass gasification
• reduce process steps?
• increase productivity for the same carbon source
GasifierPrimary gas
cleaningMCEC
Final gas cleaning
SynthesisBiomass Transport fuel
steam
CO2
O2+CO2CO2
O2CO2/O2
separation
electricity
Objectives
4
investigate Molten Carbonate
Electrolysis Cell (MCEC) for syngas
conditioning
“To produce knowledge specific to the
operating range, scale and feasibility of
MCEC as an alternative pathway to a
multiple-stage downstream conditioning of
raw-syngas (from biomass gasification) prior
to its synthesis to transport grade biofuel”
extent of linking electricity to liquid fuels
Technology track and scope of work
5
• Host facility – sawmill (generic)
• Molten Carbonate Electrolysis Cell (MCEC)
• Sustainable Aviation Fuel (SAF)Sawmill
Biomass dryingSize reduction
GasificationPrimary gas cleaning
MCECAGR
FTS & upgrading
Biomass Boiler Steam
system
Biofuels
stea
m
thQelW
SAF facility
ByproductsLu
mb
er
thQ
Timber
thQ
+
net,elW
MCEC — operational parameters
• polarization curve
• stack temperature
• methane behavior
• CO2 recycle (anode)
6
CO32- Elektrolyt CO3
2-
Positive electrode (Anode)
Negative electrode (Cathode)H2OCO2
O2: CO2 (1:2)
H2: CO (2:1)
2CO32- " O2 + 2CO2 + 4e- (R3)
H2O + CO2 + 2e- " H2 + CO32- (R1)
H2O + CO D H2 + CO2 (R2)
POWER
MCEC — operational parameters
7
polarization curves stack temperature
stack size
El. use
MCEC — operational parameters
8
methane vs current density methane vs stack temperature
Cases evaluated
9
➢ MCEC integrated with 3 gasification technologies (20 MW LHV
syngas)
▪ WoodRoll (WR, Cortus Energy AB)
▪ Dual Fluidized Bed (DFB, e.g. GoBiGas)
▪ Bubbling Fluidized Bed direct heated (BFB, Andritz Carbona)
➢ 2 process configuration
▪ side-fired steam reformer (SMR)
▪ electric heated steam reformer (eSMR)
➢ Economic indicators: investment and production cost estimates for
the studied cases
BPST
SMR AGR
FTR
Decanter
H
Dryer
Sawn wood
Timber
CO2+O2
steam
Gasifier
flue gas
air
process heat
Cryogenic
O2-rich
CO2
Comp.
MCEC
FTL
FT tailgas
acid gas
el.
steamsteam
process steam
condensate
Biomass boiler
sawdustwoodchips
bark
condensate
𝐎𝟐:𝐂𝐎𝟐(𝟏:𝟐)
Anode
𝟐𝐂𝐎𝟑𝟐− → 𝐎𝟐 + 𝟐𝐂𝐎𝟐 + 𝟒𝒆−
Cathode 𝐇𝟐𝐎 + 𝐂𝐎𝟐 + 𝟐𝐞− → 𝐇𝟐 + 𝐂𝐎𝟑
𝟐−
𝐇𝟐𝐎 + 𝐂𝐎 ↔ 𝐇𝟐 + 𝐂𝐎𝟐
𝐇𝟐𝐎 𝐂𝐎𝟐 𝐇𝟐 𝐂𝐎 𝐂𝐇𝟒
𝐇𝟐:𝐂𝐎(𝟐:𝟏)
𝐂𝐎𝟑𝟐− 𝐄𝐥𝐞𝐜𝐭𝐫𝐨𝐥𝐲𝐭𝐞 𝐂𝐎𝟑
𝟐−
el. CO2_cap.
el.
syngas
water
Process configuration (20 MW LHV syngas)
20 MW14-18 MW
SMR to eSMR
9-13% increase
Carbon balance (Dual fluidized bed)
11
Normalized to carbon in syngas
Carbon balance (Bubbling fluidized bed)
12
Normalized to carbon in syngas
Economic performance
Parameter Unit Value Remark
Biomass SEK/MWh 172.5 mixed bark, sawdust, woodchips
Electricity SEK/MWh 400
Oxygen SEK/ton 600
Scrubber oil SEK/MWh 1060 DFB configuration
Annuity - 0.1 ~20 years, 8% interest
O&M % 3 of Total Fixed Capital Inv. (TFCI)
Production cost
Production cost
Production cost
Concluding remarks
• MCEC activity varies depending on syngas composition & requirements for downstream upgrading, WR<DFB<<BFB
• Syngas yield increase by 15-31% compared to WGS conditioning
• For a given MCEC size, lower current densities pronounce methane content of the syngas, e.g. suitable for SNG process
• Electrification of other process sections can boost carbon efficiency, worth checking electrical heating for the gasification process (DFB & WR)
• Process capital intensive (TFCI ~55% production cost), about 35% TFCI derives from gas conditioning section that include MCEC
17
Thank you for your attention!
Questions?
This project is carried out within the collaborative research program Renewable transportation fuels and systems, financed by the Swedish Energy Agency and f3 Swedish Knowledge Centre for Renewable Transportation Fuels.
www.f3centre.se/en/renewable-transportation-fuels-and-systems/