Methanol Synthesis Kinetics Andre Chen, Anthony Chiu, Justin Foss, Ryan Ghosh, Joshua Hubbard, Rodrigo Salamanca
Overview Background Methanol Synthesis Reactions Rate Expression Development Other Kinetic Models Preliminary ASPEN Results
Methanol Background: History Ancient Egyptians use pyrolysis of wood to make methanol BASF (Germany) produces industrial- scale synthetic methanol 85 million metric tonnes produced globally Pure methanol produced Cu used as catalyst <30 BCE 1661 1905 1923 2016
Methanol Background: Energy Applications Energy resource Automotive industry: mixed with gasoline for automobile fuel Heating source Fuel cells Methanol Energy (Mitsubishi Gas Chemical, 2019)
Methanol Background: Other Applications Other Industries Construction Electronics Chemical Industry Formaldehyde Acetic Acid Alkenes (e.g. ethylene) Methanol Chemicals (Mitsubishi Gas Chemical, 2019)
Methanol Background: Market Trends Methanol global growth (ZEEP, 2019) Asian Growth US to begin exporting more than importing in 2019 Impact of weather In 2015, market for methanol was USD 29.6 Billion. By 2021, it is projected to swell to USD 54.2 Billion; this represents a 45% market growth. Methanol global growth (ZEEP, 2019)
Methanol Background: Catalyst Cu/ZnO catalyst (Xu, 2017) Catalyst Type Cu/ZnO: high selectivity and activity Al2O3 and/or ZrO2: optional additions 4-8 year lifetime Cu/ZnO catalyst (Xu, 2017)
Methanol Background: Catalyst Catalyst Mechanism Initial proposals Single-site (CO2, H2, & CO compete) Dual-site (CO2 & CO compete, H2 other side) Latest proposals CO2 & CO on different sites Active site locations still debated
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3)
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) ‘Only Carbon Monoxide’ Natta, 1955; Bakemeier et al., 1970
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) ‘Only Carbon Dioxide’ Dybkjaer, 1985; Chinchen et al., 1984
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) ‘Both CO and CO2 play a role’ Liu et al. 1985 (Carbon labeling); Denise and Sneeden (Kinetic); Klier et al. (Kinetic)
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) Synthesis of Dimethyl Ether (DME) 2CH3OH CH3OCH3 + H2O (4)
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Major Theme: Inconsistency Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) Synthesis of Dimethyl Ether (DME) 2CH3OH CH3OCH3 + H2O (4)
2. Methanol Synthesis: Reactions Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) Major Theme: Inconsistency Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) 48 different kinetic models depending on reaction theory Synthesis of Dimethyl Ether (DME) 2CH3OH CH3OCH3 + H2O (4)
3. Rate Expression Development - Graaf
3. Rate Expression Development - Graaf Experimental Setup: Spinning basket reactor (Tjabel et al. 1966)
3. Rate Expression Development - Graaf Experimental Setup: GLC Spinning basket reactor (Tjabel et al. 1966)
3. Rate Expression Development - Graaf Experimental Setup: Decreasing Pressure GLC Spinning basket reactor (Tjabel et al. 1966) Water formation (Graaf et al. 1988)
3. Rate Expression Development - Graaf Experimental Setup: Decreasing Pressure GLC Spinning basket reactor (Tjabel et al. 1966) Water formation (Graaf et al. 1988)
3. Rate Expression Development - Graaf Experimental Setup: Decreasing Pressure Thermodynamically predicted CO reaction GLC Spinning basket reactor (Tjabel et al. 1966) Water formation (Graaf et al. 1988)
3. Rate Expression Development - Graaf Experimental Setup: Must result from CO2 reaction Decreasing Pressure Thermodynamically predicted CO reaction GLC Spinning basket reactor (Tjabel et al. 1966) Water formation (Graaf et al. 1988)
3. Rate Expression Development - Graaf Carbon Monoxide Hydrogenation (1) Carbon Dioxide Hydrogenation (2) Water-Gas Shift (WGS) (3) Graaf, G.H., et al.., 1988. Kinetics of low-pressure methanol synthesis. Chemical Engineering Science
3. Rate Expression Development - Graaf Graaf, G.H., et al.., 1988. Kinetics of low-pressure methanol synthesis. Chemical Engineering Science
3. Rate Expression Development - Graaf Reduced form can be inputted to ASPEN Graaf, G.H., et al.., 1988. Kinetics of low-pressure methanol synthesis. Chemical Engineering Science
4. Other Kinetic Models Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) 4 Intermediate Steps Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3)
4. Other Kinetic Models Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) 4 Intermediate Steps Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) 6 Intermediate Steps Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3)
4. Other Kinetic Models Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) 4 Intermediate Steps Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) 6 Intermediate Steps Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) 2 Intermediate Steps
4. Other Kinetic Models Carbon Monoxide Hydrogenation CO + 2H2 CH3OH (1) 4 Intermediate Steps 4 x 6 x 2 = 48 Different Combinations Carbon Dioxide Hydrogenation CO2 + 3H2 CH3OH + H2O (2) 2 Intermediate Steps Water-Gas Shift (WGS) CO2 + H2 + Heat CO + H2O (3) 6 Intermediate Steps
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Overview of Model Development Measure CO and CO2 conversion experimentally over a range of conditions Develop expressions for kinetic parameters Relate rate expressions to CO and CO2 conversion Nonlinear regression to obtain kinetic parameters Test parameters for all 48 kinetic models - identify best performing models
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Experimental Setup Operating Conditions: Catalyst: ??? Reactor system: ??? State variables: ??? Feed: ??? Reactants were input into reactor at variables compositions
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Experimental Setup Operating Conditions: Catalyst: ??? Reactor system: ??? State variables: ??? Feed: ??? Inert gas fed in variable composition with reactants
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Experimental Setup Activity tests were carried out in an isothermal tubular fixed bed reactor (10.2 mm I.D.) with a catalyst weight of 1.0 g. (Cu/ZnO/Al2O3/ZrO2)
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Experimental Setup Reactor temperature and reactant flow rate (in terms of space velocity) were also varied experimentally
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Experimental Setup Operating Conditions: Catalyst: ??? Reactor system: ??? State variables: ??? Feed: ??? Outlet composition was analyzed by gas chromatography
Combinations of varied parameters form 28 experimental conditions for which conversion data was collected Collected experimental data of conversion for each of CO and CO2 for each of 28 experimental conditions Determined error between calculated and experimental for each of 28 conditions Averaged error among all 28 conditions and multiplied by 100 to give a percentage
Varied parameters, again, included reactor temperature, space velocity, and feed composition Collected experimental data of conversion for each of CO and CO2 for each of 28 experimental conditions Determined error between calculated and experimental for each of 28 conditions Averaged error among all 28 conditions and multiplied by 100 to give a percentage
Averaged error across all 28 conditions contributes to robustness of the developed model to varying conditions Collected experimental data of conversion for each of CO and CO2 for each of 28 experimental conditions Determined error between calculated and experimental for each of 28 conditions Averaged error among all 28 conditions and multiplied by 100 to give a percentage
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Parameter Estimation Express theoretical CO and CO2 conversion (XCO, calc and XCO2, calc) from rate equations Use nonlinear regression in MATLAB to get estimated kinetic parameters Kinetic Parameters Objective Function for Nonlinear Regression
4. Lim et al. 2009: Proposed Kinetic Model Based on Influence of CO2 Choosing Kinetic Model Choosing a kinetic model: Calculate total average errors Calculate standard deviation of error Select kinetic models which give errors/std deviations within threshold values 17% XCO error 60% XCO2 error 10% XCO STD 30% XCO2 STD CO Hydrogenation - Step 4 CO2 Hydrogenation - Step 2 Water-Gas Shift (WGS) - Step 1
5. Preliminary ASPEN Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg
5. Preliminary ASPEN PFR 1 Analysis: Feed: CO = 500 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 1 Analysis:
5. Preliminary ASPEN PFR 1 Analysis: Temperature: 100 - 1000℃ Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 1 Analysis: Temperature: 100 - 1000℃
5. Preliminary ASPEN PFR 1 Analysis: Temperature: 100 - 1000℃ Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 1 Analysis: Temperature: 100 - 1000℃ Pressure: 1 - 101 bar
5. Preliminary ASPEN PFR 1 Analysis: Temperature: 100 - 1000℃ Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 1 Analysis: Temperature: 100 - 1000℃ Pressure: 1 - 101 bar Max Methanol Flow Rate = 303.36 kmol/hr when T = 300℃; P = 101 bar
5. Preliminary ASPEN PFR 2 Analysis: Temperature: 270 - 310℃ Pressure: Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 2 Analysis: Temperature: 270 - 310℃ Pressure: 80 - 100 bar
5. Preliminary ASPEN PFR 2 Analysis: Temperature: 270 - 310℃ Pressure: Feed: CO = 500 kmol/hr CO2 = 100 kmol/hr H2 = 2000 kmol/hr Reactor: Volume = 141.37m3 Catalyst = 3000 kg PFR 2 Analysis: Temperature: 270 - 310℃ Pressure: 80 - 100 bar Max Methanol Flow Rate = 374.26 kmol/hr when T = 278℃; P = 100 bar
5. Preliminary ASPEN Optimal Operating Temperatures and Pressures PFR CSTR Temperature (℃) 278 280 Pressure (bar) 100 Methanol Flow Rate (kmol/hr) 374.26 302.883 Conversion 62.38% 50.48%
Questions? PFR CSTR Temperature (℃) 278 280 Pressure (bar) 100 Methanol Flow Rate (kmol/hr) 374.26 302.883 Conversion 62.38% 50.48%
Sources D Sheldon, 2017. Catalytic methanol industry production | Last 100 years and the future. Johnson Matthey Technology Review 61. Anon, The Many Uses of Methanol: From Clothing to Fuel. Mitsubishi Gas Chemical. Available at: https://www.mgc.co.jp/eng/rd/technology/methanol.html [Accessed February 6, 2019]. Anon, ZEEP Market Opportunities. ZEEP Fuels & Chemicals. Available at: https://zeep.com/market-opportunities/ [Accessed February 7, 2019]. Xu, Xinhai & Shuai, Kaipeng & Xu, Ben. (2017). Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen. Catalysts. 7. 183. 10.3390/catal7060183. Tajbl, D.G., Simons, J.B. and Carberry, J.J., 1966. Heterogeneous Catalysis in Continuous Stirred Tank Reactor. Industrial & Engineering Chemistry Fundamentals, 5(2), pp.171-175. Graaf, G.H., Sijtsema, P.J.J.M., Stamhuis, E.J. and Joosten, G.E.H., 1986. Chemical equilibria in methanol synthesis. Chemical Engineering Science, 41(11), pp.2883-2890. Graaf, G.H., Stamhuis, E.J. and Beenackers, A.A.C.M., 1988. Kinetics of low-pressure methanol synthesis. Chemical Engineering Science, 43(12), pp.3185-3195. Graaf, G.H., Scholtens, H., Stamhuis, E.J. and Beenackers, A.A.C.M., 1990. Intra-particle diffusion limitations in low-pressure methanol synthesis. Chemical Engineering Science, 45(4), pp.773-783. Lim, H. W., Park, M. J., Kang, S. H., Chae, H. J., Bae, J. W., & Jun, K. W. (2009). Modeling of the kinetics for methanol synthesis using Cu/ZnO/Al2O3/ZrO2 catalyst: influence of carbon dioxide during hydrogenation. Industrial & Engineering Chemistry Research, 48(23), 10448-10455.
Final kinetic models - Graaf