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Hydrocarbon Separation via Metal–Organic Frameworks

Hydrocarbon Separation via Metal–Organic Frameworks. Article: Hydrocarbon Separations in a Metal-Organic Framework with Open Iron(II) Coordination Sites. Eric D. Bloch. Science: 335 (6076), 1606-1610. [DOI:10.1126/science.1217544] Group 14 Marcela HERNANDEZ Matt TRAHAN Clemence CHAPEAUX

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Hydrocarbon Separation via Metal–Organic Frameworks

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  1. Hydrocarbon Separation via Metal–Organic Frameworks Article: Hydrocarbon Separations in a Metal-Organic Framework with Open Iron(II) Coordination Sites. Eric D. Bloch. Science: 335 (6076), 1606-1610. [DOI:10.1126/science.1217544] Group 14 Marcela HERNANDEZ Matt TRAHAN Clemence CHAPEAUX Christian MORENO Source: <http://www.sulzer.com/en/Industries/Hydrocarbon-Processing/Gas-Processing>

  2. Summary • Introduction • Olefin-Paraffin Mixture • Cryogenic Distillation • Fe2(dobdc) • Tests for Analysis of Fe2(dobdc) • Hydrocarbon Adsorption • Neutron Powder Diffraction • Variable Temperature Magnetic Susceptibility • Binding strength of Hyrdocarbons • Absorption Selectivities • Fe2(dobdc) Performance • Overall Separation Process • Conclusion • Assessment • Comparing to other research • Further research suggestions Fe2(dobdc) molecule Source: http://www.sciencemag.org/content/335/6076/1606.full

  3. Introduction • Separation of Olefin-Paraffin mixtures is performed via cryogenic distillation • New material to perform the separation would save time, money, and energy • Fe2(dobdc) provides an active metal-organic framework for separation of hydrocarbons Metal Framework isolating different hydrocarbon molecules Source: http://www.nature.com/srep/2013/130128/srep01149/full/srep01149.html?WT.ec_id=SREP-639-20130201

  4. What is an Olefin-Paraffin Mixture? • Olefin: Unsaturated carbon molecule • Paraffin: Saturated carbon molecule • Definition of Saturation: A saturated compound has no double or triple bonds • Example of Mixture includes: ethylene/ethane and propylene/propane Ethylene Ethane Propylene Propane Source: <http://en.wikipedia.org/wiki/Propylene>, <http://en.wikipedia.org/wiki/Propane>, <http://en.wikipedia.org/wiki/Ethylene>, <http://en.wikipedia.org/wiki/Ethane>

  5. Olefin-Paraffin Mixture • Due to similar size and volatilities, separation requires cryogenic distillation • Molecular Weight of Ethane: 30.07 g/mol • Molecular Weight of Ethylene: 28.05 g/mol • Molecular Weight of Propane: 44.10 g/mol • Molecular Weight of Propylene: 42.08 g/mol Various Hydrocarbon Boiling Points Source: <http://www.google.com/patents/EP1515790A2?cl=en>

  6. Cryogenic Distillation • Olefin-Paraffin mixture stream is compressed to cold temperatures and high pressures • These cold temperatures and high pressures allow for the distillation of the olefin-paraffin mixture • The process is very energy-intensive Cryogenic Distillation Tower Source: <http://www.polarisengineering.com/polaris/technologies/cryogenic-distillation/>

  7. The Problem with Distillation • Olefin-Paraffin mixtures are created by "cracking" long chain hydrocarbons at high temperatures • Cracking: cracking is the process where heavy, large hydrocarbons are broken down into simpler molecules such as light hydrocarbons by the breaking of carbon-carbon bonds Long Chain Hydrocarbon Cracking Olefin-Paraffin Mixture Source: <http://www.educationquizzes.com/gcse/chemistry/crude-oil-2/>

  8. Problem with Distillation • Substantial energy cost arises from cooling these hot gases to the low temperatures required for cryogenic distillation Source: <www.prometheusenergy.com>

  9. Solution • Use new material to enable efficient separation at higher temperatures and atmospheric pressure • Process would include a Packed Bed Reactor using Swing Adsorption • Distillation not required • Result would be huge energy savings Packed Bed Adsorption Pellets Source:<http://encyclopedia.che.engin.umich.edu/Pages/Reactors/PBR/PBR.html>

  10. Material: Fe2(dobdc) • Metal organic Framework • Exposed iron (II) coordination sites • May be capable of fractionating a methane/ethane/ethylene/acetylene mixture into its pure components Fe2(dobdc) Molecule Source: <http://www.sciencemag.org/content/335/6076/1606.full>

  11. Test 1: Hydrocarbon Adsorption • Purpose: Determine the ability of Fe2(dobdc) to adsorb light hydrocarbons • Use pure component equilibrium isotherms for methane, ethane, ethylene, acetylene, propane and propylene • These isotherms were measured at 318, 333 and 353K Diagram demonstrating adsorption Source: commons.wikimedia.org

  12. Hydrocarbon Absorption Results Results: Conclusion: Fe2(dobdc) has a strong affinity for unsaturated hydrocarbons (acetylene, ethylene, propylene) at 1 bar Graph that determines Fe2(dobdc)'s affinity from different hydrocarbons at 318K Source: http://www.sciencemag.org/content/335/6076/1606.full

  13. Test 2: Neutron Powder Diffraction • Purpose: Determine nature of the interactions of the hydrocarbons with Fe2(dobdc) • Fe2(dobdc) is dosed with deuterated gas at 300K and cooled at 4K to collect data • Rietveld refinements (computational model to obtain the characterization of crystalline materials) were performed against this data to acquire structural models Diagram of the Neutron Powder Diffraction process Source: neutrons.ornl.gov

  14. Neutron Powder Diffraction Results Results: • Provided structural models for Fe2(dobdc) • All these hydrocarbons have an orientational disorder Conclusion • Fe2(dobdc) has one adsorption site where unsaturated hydrocarbons have a predisposition to bind to • Fe2(dobdc) maintains a high spin electron configuration when bond to these unsaturated gases Molecules obtained during neutron powder diffraction Source: http://www.sciencemag.org/content/335/6076/1606.full -----

  15. Test 3: Variable-Temperature Magnetic Susceptibility • Purpose: To probe the electronic state of the iron centers upon gas binding • On its own, Iron(II) exhibits weak ferromagnetic coupling along the oxo-bridged chains, and weaker antiferromagnetic coupling between chains. Image of Oxo-Bridge Chain of Lead Source: http://origin-ars.els-cdn.com/content/image/1-s2.0-S1387700308003341-gr3.jpg

  16. Test 3: Variable-Temperature Magnetic Susceptibility (cont.d) • Figure 3. Weak interacting adsorbates (alkanes) only slightly diminished the strength of ferromagnetic exchange. Strong interacting (alkenes) had a stronger effect on the iron centers, enough to make intrachain coupling from ferro to antiferromagnetic. • Conclusions: Strength of iron-hydrocarbon interactions increase as such: methane < ethane < propane < propylene < acetylene < ethylene Figure 3. Variable –temperature magnetic susceptibility Data Source: http://www.sciencemag.org/content/335/6076/1606.full

  17. Test 4: Binding Strength of Hydrocarbons withFe2(dobdc) • Determine the strength of hydrocarbon binding within Fe2(dobdc) through the analysis of adsorption data • Calculate isosteric heats of adsorption to compare the binding enthalpies of the gases Hydrocarbons tested for bonding strength with Fe2(dobdc) Source: http://sijieluo.files.wordpress.com/2012/09/mof.png

  18. Binding Strength cont' Results: • Heats of adsorption for the gasses show a significant reduction as the loading approaches the value corresponding to one gas molecule per iron(II) center presenting the strongest adsorption sites in the material Conclusion: • Fe2(dobdc) binds strongly to the light hydrocarbons tested Hydrocarbon bonding with Fe2(dodbc) Source:http://patentimages.storage.googleapis.com/US20130053585A1/US20130053585A1-20130228-D00031.png

  19. Test 5: Adsorption Selectivities • After determining that hydrocarbons bond strongly with Fe2(dobdc), the next test was to compare the adsorption of hydrocarbons to Fe2(dobdc) with other metal organic frameworks to determine which would be the most effective at separation • Calculate adsorption selectivities using ideal adsorbed solution theory • Compare adsorption select of Fe2(dobdc) and a number of other porous materials with analogous gas uptake properties Source: http://chemistry.st-andrews.ac.uk/staff/rem/group/?page_id=4

  20. Adsorption Selectivities cont' Results:The adsorption selectivities obtained for Fe2(dobdc) are significantly greater thanthose calculated for either zeolite NaX or the isostructural metal-organic framework Mg2(dobdc) Conclusion: Fe2(dobdc) is a better choicefor adsorbing hydrocarbons than Mg2(dobdc) or zeolite NaX Associating Binding Sites with Increased Enthalpy of Adsorption Source: http://www.ncnr.nist.gov/staff/craig/

  21. Test 6: Fe2(dobdc) Performance • Material performance was evaluated in an experimental packed bed reactor with an adsorption based process • Packed Bed: a packed bed is vessel that is filled with a packing material that could contain catalyst particles or adsorbents • Adsorption: the adhesion of molecules from a gas or liquid to an adsorbent surface such as Fe2(dobdc) • Breakthrough experiments were performed over a packed bed with equimolar mixtures of ethylene/ethane and propylene/propane Small Scale Packed Bed Reactor Source: <http://seat.massey.ac.nz/projects/yearbook/yearbook12/project.asp?id=09084363363>

  22. Fe2(dobdc) Performance cont'd • Outlet gas was monitored by gas chromatograph equipped with flame ionization detector to detect purity of each component of the gas mixture • As expected, alkane was first to elute from the packed bed while the solid adsorbent (Fe2(dobdc)) retained the olefin Flame Ionization Detector Source: <http://www.cambustion.com/products/hfr500/fast-fid-principles>

  23. Fe2(dobdc) Performance Results • Outlet Propane was 100% pure • Outlet Propylene during desorption was 99% pure • Outlet ethane was 99.5% pure • Outlet ethylene during desorption was 99% pure • Desorption: process where a substance is released from the adsorbent. The process is the opposite of adsorption Packed Beds of Fe2(dobdc) Adsorbent Purified Outlet Propane or Ethane Feed Outlet Propylene or Ethylene During Desorption Source: <http://www.sciencedirect.com/science/article/pii/S1383586602002083>

  24. Fe2(dobdc) Performance Results • Breakthrough simulations indicated Fe2(dobdc) with greater production capacities than Mg2(dobdc) and zeolite NaX • Fe2(dobdc) proved to be effective with purifications of at least 99% for both ethane/ethylene and propane/propylene mixtures Fe2(dobdc) Source: <http://www.sciencemag.org/content/335/6076/1606.full> Mg2(dobdc) Source: <http://www.cchem.berkeley.edu/co2efrc/publications/2011/selective-binding-of-o2.html> Zeolite NaX Source: <http://en.wikipedia.org/wiki/Zeolite>

  25. Overall Separation Process How would this process potentially work in place of cryogenic distillation? 1) A gas mixture of methane, ethane, ethylene, and acetylene are fed into the first of 3, Fe2(dobdc) beds. 2) The first fraction, methane, breaks through first because it has the lowest adsorptivity. Thus pure methane can be collected. 3) Pure methane can be collected until ethane breaks through. Overall Process of Gas Separation Source: http://www.sciencemag.org/content/335/6076/1606.full

  26. Overall Separation Process (cont.d) 4a) Gas flow is diverted to a second iron bed, from which more pure methane is collected. 4b) A mixture of ethane and ethylene are desorbed from this second bed. 5) The third Fe2(dobdc) bed is used to separate the ethane and ethylene components Overall Process of Gas Separation Source: http://www.sciencemag.org/content/335/6076/1606.full

  27. Conclusion • The advantage of switching from current process technologies to the metal-organic framework of Fe2(dobdc) is to save money and energy • The prospects of using this material as a solid adsorbent through: • pressure/temperature swing adsorption • membrane-based applications Fe2(dobdc) Molecule Source: <http://www.sciencemag.org/content/335/6076/1606.full> Source: <http://www.gtresearchnews.gatech.edu/energy-efficient-separations/l> :

  28. Assessment • Fe2(dobdc) is a good material to use for the separation of light hydrocarbon gases • Fe2(dobdc) effectively separates hydrocarbons at a reduced cost compared to the current methods The multistage separation is illustrated above where different Hydrocarbons are represented by each shape. Shows how each one can be separated out individually as it passes through the metal organic framework, Fe2(dodbc) Source: http://www.cchem.berkeley.edu/co2efrc/publications/2012/co2ch4-ch4h2-and-co2ch4h2.html

  29. Comparing To Other Research • Other research includes using Fe2+ to store hydrogen and absorb carbon dioxide • Iron has a metal organic framework useful in capturing most gases • Gases could also include harmful greenhouse gases Smog and Pollution from Greenhouse Gases Carbon Dioxide Molecule Source: (Top Left)<http://scholarsinida.blogspot.com/, (Bottom Left)<http://commons.wikimedia.org/wiki/File:CO2.png>, (Right)<http://www.deathandtaxesmag.com/190932/scientists-convert-greenhouse-gases-to-energy/>

  30. Further research suggestions • Removal of acetylene from ethylene produced in naphtha cracker using Fe2(dobdc) • Investigate the use of Fe2(dobdc) in membrane based technology • Full scale testing of Fe2(dobdc) in swing absorber Membrane made of Fe2(dobdc) Source: <http://www.beilstein-journals.org/bjoc/single/articleFullText.htm?publicId=1860-5397-6-86> Large Scale Swing Adsorber Unit Source: <http://www.gongtongmachinery.com/2-4-adsorption-plant.html>

  31. References • Bloch, E.D.; Brown, C.M.; Krishna, R.; Long, J.R.; Queen,W.L.; Zadrozny, J.M., Science 2012, Vol 335, 1606-1610. http://www.sciencemag.org/content/335/6076/1606.full • Brown, C.M.; Dailly, A.; Grandjean, F.; Herm, Z.R.; Horike, S.; Kaye, S.S.; Long, G.J.; Long, J.R.; Queen, W.L.; Sumida, K., Chemical Science 2010, Vol 1, 184-191. http://alchemy.cchem.berkeley.edu/jeff/paper112.pdf

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