Hydrocarbon Storage Simulation in Rhodium Software and Validation via Reactor Testing Presented By: Minnie Lahoti Engineer Southwest Research Institute Advance Science. Applied Technology 1
Overview Rhodium - Background Rhodium Application Simulation Results Experimental Plan Results & Discussion Summary Rhodium Validation 2
Rhodium A Protein Docking Software Performs Unbiased, Traceable Small Molecule Docking Simulations Over Proteins Verified Application Drug delivery optimization Protein engineering Apply Concept to HC Storage in Zeolites for Automotive Industry HC storage in DOCs during cold start HC storage: physical process Match between HC size and zeolite pore size 3
Preface - Simulation Explore Thermodynamic Modeling Capabilities of Rhodium Understand Shortcomings Address in Future Work Predict Performance of Zeolites in Adsorption and Desorption of Hydrocarbons (HC) Select a Series of Zeolites Widely Used in Automotive Industry Conduct HC Storage Simulations on Selected Zeolites 4
Structure-Based Modeling: Decane in ZSM-5 Crystal Lattice Of Zeolite Represented By 3x3x3 Unit Cells, Or 27 Total Low & High Resolution Pose Search HCs Added ~5 Molecules/Unit Cell Rhodium Assumes no Reaction Between Zeolite & HC Purple: Searching Sites for Potential Docking 5
Progression of Dodecane Occupying a Zeolite Cavity Occupancy Score (CAVOC) 2nd Dodecane Affinity Near 1st Molecule Increased van der waals forces Sodalite and Supercages Fill with Dodecane Dodecane occupy different sections of zeolite Excellent Visual Representation of Zeolite and HC Interaction 6
Simulation Example Decane Packing in High SiO2/Al2O3 ZSM-5 Cavity-Occupancy Pose and Scores CAVOC Score Highest for Dodecane 7
Simulation Details 10 HCs chosen from Advanced Combustion Catalyst & Aftertreatment Technology (AC 2 AT) Emission Characterization Consortium HCs simulated were C1-C12 Methane, Ethene, Propene, Propane,,Dodecane Models Of 25 Zeolite Types Were Used In The Simulations Zeolites To Be Wash Coated Were Selected Based On Simulated Selectivity, Commercial Availability, Thermal Stability 8
Simulation Results Various Zeolite Structures Simulated with 10 Different Sized HCs (Methane to Dodecane) Choose Zeolites with the Highest Selectivity for Light HCs, Heavy HCs and Varying SiO 2 /Al 2 O 3 ratio (high and low end) Simulations Are More Efficient Than Experimentally Deriving Results 9
Simulation Results Based on the Simulation Results and the Availability of Zeolites, the Following Were Used to Wash-Coat Catalyst Cores: MFI-ZSM-5 (low SiO 2 /Al 2 O 3 ratio ~15-45) MFI-ZSM-5 (high SiO 2 /Al 2 O 3 ratio ~371) CHA-SSZ-13 (light HC storage) MTW-ZSM-12 (heavy HC storage) MFI MTW CHA http://asia.iza-structure.org/ 10
Simulation Results Simulation Results Shown For Idealized Zeolite Structures ZSM-5 With High SiO 2 /Al 2 O 3 Ratio Shows Highest Selectivity For Most HCs 11
Preface - Experimental Wash Coat Catalyst Cores with the Best Zeolite Candidates Evaluate HC trapping efficiency via Automated Universal Synthetic Gas Reactor (USGR ) system HCs chosen from Advanced Combustion Catalyst & Aftertreatment Technology (AC 2 AT) emission characterization project USGR 12
Experimental Plan Zeolite/Binder Slurry Preparation Zeolite sieved through 180 µm mesh Powder dissolved in DI water 0.2 g/ml Nyacol Alumina Binder Solution Added to Slurry With 1:10 Binder To Water Ratio Stir For At Least Half Hour Before Wash-coating 13
Experimental Plan Catalyst Preparation Pre-Calcined Monoliths Dipped in Slurry Excess Slurry Removed via Compressed N 2 Placed Horizontally in the Oven at 200 C for 20 min Process Repeated Until ~1 g/cm 3 Zeolite Loading Achieved 14
Experimental Testing via USGR HC Mixture Simulated Capability to Inject Liquid HCs With Fast Response Time Storage Testing Conducted at 100 C S.V. 60,000 hr -1 Gas Concentrations Measured Via FTIR Concentration (ppm) Dodecane Storage T = 100 C Dodecane Time (s) 15
Catalyst Characterization BET Surface Area and SEM Images Understand uniformity of washcoating High ZSM-5 washcoated poorly Low ZSM-5 SSZ-13 Zeolite BET Surface Area (m 2 /g) SSZ-13 74.92 ZSM-5 High SiO 2 /Al 2 O 3 43.77 ZSM-5 Low SiO 2 /Al 2 O 3 59.52 ZSM-12 34.07 High ZSM-5 ZSM-12 16
Experimental Storage Results ZSM-5 Superior To All Other Catalyst Results Match Simulation MFI Zeolite Structure Selective for Dodecane and Decane 17
Storage Results ZSM-12 vs. SSZ-13 Prediction: ZSM-12 Better for Heavy HC, SSZ-13 Light HC Storage Testing Confirms Prediction 18
Storage Results Low vs. High SiO 2 /Al 2 O 3 Ratio ZSM-5 High ZSM-5 Superior High SiO 2 /Al 2 O 3 Ratio Allows Greater Acid Sites for HC species Interaction with Surface 19
Simulation vs. Test Results Selectivity Trend Predicted Correctly But Not Quantitatively 20
Simulation vs. Test Results Propene Storage Not Predicted Reactivity not predicted in Rhodium 21
Conclusions 4 Zeolites Chosen Based on Simulations & Availability MFI-ZSM-5 (low SiO 2 /Al 2 O 3 ratio) MFI-ZSM-5 (high SiO 2 /Al 2 O 3 ratio) CHA-SSZ-13 (light HC storage) MTW-ZSM-12 (heavy HC storage) Simulation and Test Results Confirm ZSM-5 High Superior Excellent Visual Tool For HC and Zeolite Interaction Simulations Conducted in 3 to 4 weeks DFT Simulations 3 to 6 months Experimental Testing 6 months to over a year 22
Future Work Incorporate New Features into Rhodium Software Discrepancy Between Simulations and Test Results Simulations do not account for chemistry Propene reactivity not accounted for Simulations do not have a flow direction No ability to provide space velocity variations Lack of crystallography on tested materials Lack of zeolites with required SiO 2 /Al 2 O 3 Ratio Combination of Zeolites for Improved HC Storage 23
Future Work Change Type of Zeolite, Counterion Look at Reduction and Oxidation Reactions Based on Lewis Acid and Bronsted Acid Sites Apply Concepts to Predict NO X -SCR Catalyst Reactions Zeolite Zeolite + PGM NO X SCR 24
Acknowledgement Dr. Jonathan Bohmann Rhodium Software Southwest Research Institute Funding Internal Research Dr. Cary Henry Assistant Director Dr. William Epling, Dr. Yasser Jingjou, Kevin Gu University of Virginia Team Members: Dr. Robert Henderson Research Engineer Chris Sharp Staff Engineer Scott Eakle Principal Engineer Bryan Zavala Engineer Seth Brenneman Research Engineer Ryan Hartley Graduate Student Nate Martinez Senior Technician 25
Contact Information: Name: Minnie Lahoti Email: minnie.lahoti@swri.org Desk Phone: (210) 522-5575 26