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MefCO2 Final dissemination event
Catalyst and process engineering
Matej Huš, Kemijski inštitut
James Hayward, Cardiff Catalysis Institute
28th May, 2019
MefCO2 – Methanol fuel from CO2
Methanol synthesis-commercial/emerging technologies
Feedstock: fossil fuel based vs carbon dioxide based
More than 40 million metric tons produced annually
Syngas sources:
• Natural gas steam reforming (≈75 %)
• Coal gasification (≈ 10 %)
• Mainly CO and H2
Or:
• Waste CO2+H2 produced at electricity peaks
• Mainly CO2 and H2→Modification of catalyst
History
• Before 1923-dry distillation of wood
• 1923-1966 Mittasch high pressure process
• 1966-present ICI low pressure process
MefCO2 – Methanol fuel from CO2
Methanol synthesis-commercial technologies
Reactor types*
Process conditions: 200-300 °C, 50-100 bar
Features
• Suited for large scale operation (up to million ton per year)
• Conditions suited for fast reaction in compromise with equilibrium
• Utilization of reaction heat
Disadvantages
• Not responsive to varying load
• Not economic out of design conditions
*G. Bozzano, F. Manenti, Efficient methanol synthesis: Perspectives, technologies and optimization strategies, Progress in energy and Combustion Science 56 (2016) 71-105
MefCO2 – Methanol fuel from CO2
Aims of the Research
Improving upon existing catalyst systems
Initial Catalyst Modifying the Catalyst Applying Understanding
• Based on ICI catalyst developed in the 1960s
• Catalyst consists of a mixture of copper, zinc, and alumina
• Copper is the active phase
• Materials prepared by co-precipitation
• Precursor phase is malachite
• Changes in metal ratios:
• Altering the relative amounts of copper, zinc and alumina
• Changes in substrates
• Substitution of the zinc for different elements
• Ce, Zr, Mg, Ga, Al, In, Mn, Ti, Si
• Changes in dopants
• Substitution of the alumina for different elements
• B, Ga, In, Mg, Sn, Ce, Zr
• Catalysts screened in multi-bed reactor
• Wide range of characterisation techniques used
• What trends can we observe?
• Can we use these trends in catalyst design?
MefCO2 – Methanol fuel from CO2
Initial Results
Modifications of the malachite precursors
Screening conditions: 200 – 300 °C, 20 bar pressure, 1:3 CO2:H2 gas mix
• Increased copper loading does not always increase activity
• Increased surface area of overall material a factor
• Malachite phase important, but mostly because of effect on copper specific surface area
• Dominant trend: Increase in copper specific surface area increases yield
• What approaches can we take to improve copper SSA?
MefCO2 – Methanol fuel from CO2
Improving on Malachite
Alternative preparation methods and precursor phases
Magnesium substitution and Supercritical Antisolvent (SAS) Precipitation
Partial substitution of Zn byMg can lower Cu particle size
Complete substitution lesseffective; some zinc needed
SAS process produces higherCu surface areas
Time and resource intensive
Catalyst Cu SSA (m2/g)
SAS 1 32
SAS 2 33
SAS 3 31
SAS 4 34
Mg % Cu SSA (m2/g)
0 31
10 36
20 35
30 33
MefCO2 – Methanol fuel from CO2
Improving on Malachite
Treated hydrotalcite precursors
Hydrotalcite structure: Treatment Effects: Testing Data:
Reported in literature to havesmaller copper nanoparticles
Aggregation of layers reducessurface area
Solvent treatment to preventaggregation?
Increased activity vs. industrialstandard
Studies into stability and scale-upneeded
Potential new precursor?
Standard Untreated Treated
Surface
Area
75-90 21 339
Cu Surf.
Area
28 7 55
MefCO2 – Methanol fuel from CO2
Catalyst screening reactor
5 parallel reactors
• More than 60 catalysts tested
• Almost 24/7 operation
• User friendly
• 20-400 °C
• 10-250 sccm
• 10-85 bar, with modification up to 100 bar
• Versatility
• Recycle reactors are rare on laboratory scale, commercially not available
Mass flow controllers
Heated sampling system
Micro gas chromatograph
Reactor with catalyst cartridge
Gas recycle
MefCO2 – Methanol fuel from CO2
Catalyst screening - experimental
Procedure
Distribution of basic sites - Alkali earth metals i.e. Ca, Mg, Sr and Ba Copper metallic phase – Calcination temperature, Ultrasonic, Hydrothermal Solution combustion and Solid state methods
Catalyst Material Metal
Alkaline earth metal catalysts
Cu-Alkali earth metal-Alumina
Ca, Mg, Sr and Ba
Best alkali metal proceeded to the second step
Transition metal catalystsTranition metal- alkali
metal-AluminaNi,Mn, Fe and Co
Best catalyst from this stage proceeded to the third step
Effect of supports TM-ALKM-supports Al, Si, Ti, Ce and Zr
Best catalyst from this stage proceeded to the fourth step
Promoted catalystPromoter-(Good catalyst and Bad catalysts from three stages)
Na, K, Cs, Cr, V and Mo
MefCO2 – Methanol fuel from CO2
Catalyst screening - experimental
Effect of Cu+/Cu0 ratioCatalyst activity at T = 250 °C and P = 20 bar
Time on-line analysis over Zn and Mg based catalysts (CO2:H2 = 1:3, GHSV = 6000 h-1, P = 20 bar)
MefCO2 – Methanol fuel from CO2
Process modelling
DFT (first-principles)
Cu-based: Zn, Cr, Fe and Mg inverse catalysts tested
Detailed structures of all possible intermediates
MefCO2 – Methanol fuel from CO2
Process modelling
DFT (first-principles)
Mechanism
Rationale: To optimise the process for non-ideal conditions (impurities, different T, pressure, CO2 feed)
MefCO2 – Methanol fuel from CO2
Process modelling
Mesoscale (catalytic surface)
Kinetic Monte Carlo simulations
MefCO2 – Methanol fuel from CO2
Process modelling
Mesoscale (catalytic surface)
Mean-field microkinetics Selectivity at laboratory conditions for four different catalysts
MefCO2 – Methanol fuel from CO2
Process modelling
Micro-kinetics coupled with CFD
Pressure drop and packing
hp
dDS
MefCO2 – Methanol fuel from CO2
Process modelling
CFD simulations with micro-kinetic model
Parameter Value Unit
ρs 1770 [kg m−3]
dp 5.47×10−3 [m]
cps 5.0 [kJ kg−1
K−1]
λc 0.004 [W m−1
K−1]
av 626.98 [m2 m−3]
es/ 0.123 [–]
Tube length 7.022 [m]
Layer
Thickness
8×10−7 [m]
Tube diameter 0.038 [m]
Shell diameter 0.053 [m]
Over 15000
pellets
Lurgi catalyst specifications
Packing in a single tube
MefCO2 – Methanol fuel from CO2
Take-home message
Patents, publications and presentations
• Extensive and systematic experimental testing of prospective catalysts
• More than 60 catalysts synthesised and tested + industrial ones (e.g. Lurgi)
• CO2 hydrogenation to methanol is a mature process. However, niche catalysts were synthesised and tested for non-optimal conditions.
• Most important effects determining the performance: Cu+/Cu0 ratio, secondary metal, support, dispersion, method of preparation
• Multiscale modelling:
• First-principles calculations show the reaction mechanism
• Meso-scale simulations show the temporal evolution of the catalytic surface
• Coupling with CFD necessary to describe the process on a macroscopic level
• Results of high scientific importance:
• Huš M. et al. ACS Catalysis 2019, 9 (1), 105-116
• Dasireddy V. D. B. C. et al. Renewable energy 2019, 140, 452-460.
• Dasireddy V. D. B. C. et al. Fuel, 2018, 233, 103-112.
• Dasireddy V. D. B. C. et al. Journal of CO2 utilization, 2018, 28, 189-199.
• Pavlišič A. et al. Powder technology, 2018, 323, 130-139.
• Huš M. et al. Applied Catalysis B: Environmental 2017, 207, 267-278.
• Huš M. et al. Catalysis Science & Technology 2017, 7 (24), 5900-5913.
• Kopač D. et al. The Journal of Physical Chemistry C, 2017, 121 (33), 17941-17949.
• Hayward J. S. et al. ChemCatChem, 2017, 9 (9), 1655-1662.
• The effects of partial magnesium substitution on green methanol catalysts, submitted
• Delaminated hydrotalcites as precursors for green methanol catalysts, submitted
Conference contributions:
• UK Catalysis Conference
• Faraday Discussion
• Cardiff Catalysis Conference
• AIChE,
• North American Symposium on Chemical Reaction Engineering
Patent applications:
• Patent Pending GB1701382.2 – Catalyst suitable for methanol synthesis
This project has received funding from the European Union’s Horizon
2020 research and innovation programme under grant agreement
No 637016.
Thank you