Post on 02-Apr-2018
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CO2 valorization in a biomass to fuel process: experimental gasification study and process
evaluation
12th of May 2015
Symposium on Renewable Energy and Products from Biomass and Waste
Sylvie VALIN, Laurent BEDEL, Pierre-Alexandre SETIER (CEA, LITEN)Sébastien GROS (EDF)
ANR-10-BIOE-000212th May 2015 - Symposium on Renewable
Energy and Products from Biomass and Waste
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 2
Overview of the presentation
The RECO2 project
Experimental investigation: CO2 in the gasification process
Technical assessments of SNG and FT pathways
Conclusions
20 MAI 2015 | PAGE 2
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 3
The RECO2 projectR&D project:
Objective: to assess the interest of CO2 recycling in a biomass gasification process, to synthesize gaseous (bio-SNG) or liquid fuels (Fischer-Tropsch diesel)
Gasification is performed in a dual fluidised bedCO2 is recycled in the process, replacing N2 (biomass feeding) and/or steam
3 years-project (2010-2013) funded by the French ANR (Agence Nationale pour la Recherche)Partnership:
20 MAI 2015| PAGE 3
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 4
Overview of the presentation
The RECO2 project
Experimental investigation: CO2 in the gasification process
Technical assessments of SNG and FT pathways
Conclusions
20 MAI 2015 | PAGE 4
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 5
The fluidised bed facility
Ar/CO2
N2 H2O
To µGC
To tar protocol
Cold traps for water
Feeding screw (heated)
Biomass bunker
Pressurized vessel
Metallic filter
Internal reactor
Electric resistance heaters
Lower partΦ = 0.124 m
Disengagement zone
Φ = 0.20 m
CO2
Tmax 1000°C
Pabs 1.5 to 12 barsBiomass feeding rate 0.3-5 kg/h
Product analysis/quantification
Dry gas: µGCWater: condensationTar protocol (isopropanol) + GC-FID quantification
Ar
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 6
CO2 as a substitute of steam in fluidising gas
Experimental conditions
20 MAI 2015 | PAGE 6
Temperature 850°C
Pressure 1.5 bara
Biomass Beech wood particles 1-2mm
Woody biomassfeeding rate
3 kg/h
Bed material SiC
Fluidising velocity 0.17 m/s
Fluidising gas 40 vol% N2
60vol% (H2O, CO2) withCO2/(CO2+H2O) ratio from 0 to 100%
Ref test (without CO2):H2O/C mass ratio=1.2
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 7
CO2 as a substitute of steam in fluidising gas
20 MAI 2015 | PAGE 7
Main gas species yields: mainly influenced by H2O/CO2 addition and by water-gas shift equilibrium: CO + H2O ↔ CO2 + H2
In agreement with a rather steady (CO+CO2) net yield
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 8
CO2 as a substitute of steam in fluidising gas
20 MAI 2015 | PAGE 8
No significant influence on minor hydrocarbons – nor on tar contentConversion of tar and BTX seems to be as efficient in atmosphere rich in H2O or CO2
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 9
CO2 as a substitute of steam in fluidising gas
20 MAI 2015| PAGE 9
No significant influence on C conversion nor on CGEAs expected, H2/CO ratio decreases as more steam is substituted by CO2
Ratio always too low for SNG or FT synthesis – for direct DME synthesis: the target -1- can be reached
biomassinCInputCOinCInputgasinCXC
2
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CO2 as a substitute of inert gas in feeding system
20 MAI 2015| PAGE 10
C conversion and CGE increase with total oxidant inputThis additional oxidant input –more or less important according to the reactor –should be taken into account
Substitution of inert gas by CO2 in the feeding system induces an increase of total oxidant input in the reactor
• Study of the influence of total oxidant input
Gasification study: to summarise
Substitution of steam by CO2 in the fluidising gas:• Only significant chemical influence = modification of WGS equilibrium• Carbon conversion and CGE not significantly modified
In the global process, no influence on the biofuel yield expected• H2/CO ratio decreases as more H2O is replaced by CO2: could be of interest for direct DME synthesis
Substitution of inert gas by CO2 in the feeding system: • increases the total oxidant input • can increase the gasification efficiency + WGS equilibrium and H2/CO ratio
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 11
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 12
Overview of the presentation
The RECO2 project
Experimental investigation: CO2 in the gasification process
Technical assessments of SNG and FT pathways
Conclusions
20 MAI 2015 | PAGE 12
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 13
Description of the process (SNG & BtL)
orGasifier Syngas cleaning
SNG synthesis & upgrading
FT synthesis& upgrading
Compo adjustment
Off-gas C5+
SNGAspen +
Prosim+
Biomass
100 MW
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 14
Description of the process (SNG & BtL)
3 alternatives for adjustment of syngas composition:Autothermal option: water-gas-shift reaction (WGS) → H2 ↑ CO↓Allothermal option: addition of electrolytic H2 → H2 ↑
with CO transformation into fuelwith CO+CO2 transformation into fuel (SNG: CO2 methanation - BtL: RWGS)
orGasifier Syngas cleaning
SNG synthesis & upgrading
FT synthesis& upgrading
Compo adjustment
WGS or
Off-gas
H2
Aspen +
Prosim+
C5+
SNG
Biomass
100 MW
or
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 15
Description of the process (SNG & BtL)
3 alternatives for adjustment of syngas composition:Autothermal option: water-gas-shift reaction (WGS) → H2 ↑ CO↓Allothermal option: addition of electrolytic H2 → H2 ↑
with CO transformation into fuelwith CO+CO2 transformation into fuel (SNG: CO2 methanation - BtL: RWGS)
2 alternatives for off-gas use (BtL pathway):Electricity productionSteam reforming → recycling in the syngas
Gasifier Syngas cleaning
SNG synthesis & upgrading
FT synthesis& upgrading
Compo adjustment
WGS or
Off-gas
Electricityor
Steam reforming
H2
Aspen +
Prosim+
C5+
SNG
Biomass
100 MW
or
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 16
Description of the process (SNG & BtL)
3 alternatives for adjustment of syngas composition:Autothermal option: water-gas-shift reaction (WGS) → H2 ↑ CO↓Allothermal option: addition of electrolytic H2 → H2 ↑
with CO transformation into fuelwith CO+CO2 transformation into fuel (SNG: CO2 methanation - BtL: RWGS)
2 alternatives for off-gas use (BtL pathway):Electricity productionSteam reforming → recycling in the syngas
Different CO2 recycling ratios
Gasifier Syngas cleaning
SNG synthesis & upgrading
FT synthesis& upgrading
Compo adjustment
WGS or
Off-gas
Electricityor
Steam reforming
H2
Aspen +
Prosim+
C5+
SNG
Biomass
100 MW
CO2
CO2 CO2
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 17
Biomass conversion in dual fluidised bed: adaptation of experimental results
Choice of technologies for gas cleaning, synthesis and upgrading made on the basis of EDF and CEA experience with the support of TUW expertise
Energetic integration
Performance indicators
Mass yield (kg/kg) →
Gross energy yield (LHV) →
Net energy yield (LHV) →
Product rate (biofuel)
Dry biomass feeding rate
Energy (products)
Energy (biomass + electricity + RME)
Energy (products)
Energy (biomass)
Description and definitions
17th October 2013 - SGC Seminar | PAGE 18
Technical performances: SNG case
No influence of CO2 recycling in autothermal and “Allo / CO & CO2 → CH4” cases
Increase in mass yield with CO2 recycling in “Allo / CO → CH4” case
Production can be doubled with H2 addition
Auto Allo/ CO -> CH4 Allo/ CO+CO2 -> CH4
RWGS/WGS Always = max from biomass
17th October 2013 - SGC Seminar | PAGE 19
Technical performances: BtL case
Much higher yields with off-gas reforming
Without off-gas reforming With off-gas reforming
Autothermal case: influence of off-gas reforming
17th October 2013 - SGC Seminar | PAGE 20
Technical performances: BtL case
Similar observations as for SNG
No influence of CO2 recycling in autothermal and “Allo / CO & CO2 → CH4” cases
Increase in mass yield with CO2 recycling in “Allo / CO → CH4” case
Production can be almost doubled with H2 addition
Auto Allo/ CO -> CH4 Allo/ CO+CO2 -> CH4
With off-gas reforming
17th October 2013 - SGC Seminar | PAGE 21
CO2 net emissions for the process (SNG case)
CO2 recycling: positive influence only for “allo CO -> CH4” case
H2 addition in the process deeply decreases the CO2 net emissions (from -20% to -90%)
CO2 net emissions calculated for the process: difference between
• CO2 out (SNG upgrading + flue gas of the combustor)
• CO2 in (in the gasifier)
Gasifier Syngas cleaning
SNG synthesis & upgrading
Compo adjustment
WGS or H2
SNG
Biomass
100 MW
CO2 in CO2 out
CO2 out
12th May 2015 - Symposium on Renewable Energy and Products from Biomass and Waste | PAGE 22
To conclude on this study
For SNG and BtL process, substitution of steam by CO2 in the fluidising gas:• Positive influence only if external H2 is added in the process - with transformation of CO only into fuel
• Mass yield increases and CO2 net emissions decrease
Addition of external H2: • Increases mass yield and decreases CO2 net emissions compared to “autothermal” case• Higher influence if CO2 is transformed into fuel (methanation or RWGS)
Economic aspect: • The options with H2 addition should lead to higher costs (electrolyser, electricity) in base conditions• The facility could be used in a flexible way with H2 addition only when electricity is “cheaper” (surplus of available renewable energy)