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  • 1. KINETICS OF HYDROLYSIS OF SODIUM BOROHYDRIDE USING COBALT CHLORIDE CATALYST By Arshdeep Kaur (Research scholar) Under guidance of Pramod K. Bajpai (Distinguished Professor) Copyright 2013-2014 Dr. D. Gangacharyulu (Professor) DEPARTMENT OF CHEMICAL ENGINEERING THAPAR UNIVERSITY PATIALA-147004, INDIA. December 2013 1 12/12/2013
  • 2. Outline of presentation  Introduction  Literature Review  Experimental  Results and Discussions Copyright 2013-2014  Conclusion  Acknowledgements  References 2 12/12/2013
  • 3. 12/12/20133 Copyright 2013-2014
  • 4. ENERGY FACTS  Fossil fuels are depleted at a rate that is 100,000 times faster than they are formed.  On average, 16 million tons of carbon dioxide is emitted into the atmosphere every 24 hours by human use worldwide. Copyright 2013-2014  Coal is the single biggest air polluter and burning coal causes smog, soot, acid rain, global warming, and toxic air emission. 4 12/12/2013
  • 5. Copyright 2013-2014 Transition To Hydrogen Energy 5 12/12/2013
  • 6. HYDROGEN FACTS Hydrogen is considered as clean energy source and long term solution towards sustainable energy future.  1 kg of Hydrogen has same energy than 2.8 kg of gasoline, therefore hydrogen stores 2.8 times more energy than gasoline.  Effective storage of hydrogen is one of the key elements of hydrogen economy. 6 Copyright 2013-2014  12/12/2013
  • 7. 12/12/20137 Copyright 2013-2014
  • 8. Lit. Rev.... Physical storage in tanks Compressed Hydrogen Tanks Cyro-Compressed Hydrogen Storage Compressed Gas Storage in high pressurised tanks up to 700 Hydrogen cooled to 253oC and pressurised bars. to 6 - 350 bars in insulated tanks. High energy and cost requirements for Cost factors for cooling and pressurising pressurising gas in tanks . hydrogen gas in tanks. 8 12/12/2013 Copyright 2013-2014 Cryogenic Liquid
  • 9. Lit. Rev.... Solid state hydrogen storage (A) Adsorption, hydrogen attaches to surface of molecules as hydrogen molecules. Larger quantities of hydrogen in smaller volumes at low pressures and at temperature nearly equal to room temperature can be stored. (C) & (D) Hydrogen is strongly bound within molecular structures, as chemical compounds containing hydrogen atoms. 9 12/12/2013 Copyright 2013-2014 (B) Absorption, hydrogen molecules dissociate into hydrogen atoms that are incorporated into the solid lattice framework .
  • 10. Lit. Rev.... Storing hydrogen in chemical hydrides 0.126 H2 Specific mass (kg H / kg) 0.25 H2 Density (kg H2 / liter) 0.122 NaH + H2O → NaOH + H2 0.042 0.083 0.106 CaH2 + 2H2 O → Ca(OH)2 + 2H2 0.048 0.095 0.121 MgH2 → Mg + H2 0.076 0.076 0.110 LiAlH 4 + H2 O → LiOH + Al + 2.5 H2 0.105 0.132 0.121 TiH2 → Ti + H2 0.040 0.040 0.152 0.184 0.367 0.235 0.105 0.211 0.226 0.077 0.077 LiBH 4 + H2O → NaBH4 + 2H2O→ LiOH + HBO2 + 4H2 NaBO2 + 4H2 Fraction H Millennium Cell 35% Solution NaBH4 + 4H2 O → NaBO2 + 4H2+ 2H2O Source: M.Klanchar et al. [1] 10 12/12/2013 Copyright 2013-2014 Hydride reactions and hydrogen storage properties LiH + H2O → LiOH + H2
  • 11. Lit. Rev.... Copyright 2013-2014 Comparison of hydrogen storage properties Source: M. Klanchar et al. [1] 11 12/12/2013
  • 12. Lit. Rev.... Sodium borohydride hydrogen storage Hydrolysis Reaction NaBH4 + 2H2O NaBO2 + 4H2  Sodium borohydride reacting with water to produce hydrogen.  Generated H2 is high purity (no traces of CO and S).  It is the least expensive metal hydride commercially available, and it is safe to use, handle and store. 12 12/12/2013 Copyright 2013-2014  No side reactions or no volatile by products are formed.
  • 13. Lit. Rev.... Copyright 2013-2014 Comparison of chemical hydrides Source: Y. Wu et al. [2] 13 12/12/2013
  • 14. Lit. Rev.... Copyright 2013-2014 Volumetric storage efficiency Source: Y. Wu et al. [2] 14 12/12/2013
  • 15. Lit. Rev.... Copyright 2013-2014 Gravimetric storage efficiency Source: Y. Wu et al. [2] 15 12/12/2013
  • 16. Lit. Rev.... CoCl2 + 2NaBH4 + 3H2O  25/4H2 + 1/2Co2B + 2NaCl Cl- is neoclophilic in nature, Co2+ is electrophlic in nature, which increase its reactivity toward BH- ions . Therefore this explains better reactivity of CoCl2 for NaBH4. Source:O.Akdim et al. [3] 16 12/12/2013 Copyright 2013-2014 Cobalt chloride as a catalyst for hydrolysis reaction
  • 17. Lit. Rev...... S. No Hydrogen storage modes Observations References Hydrogen storage with chemical hydrides Hydrogen fraction found best in LiBH4(0.184), LiH(0.126), LiAlH4 (0.105), NaBH 4 (0.105) Klancher et al., 2003 2. Various modes of hydrogen storage Energy density increases from compressed hydrogen storage <cryo- compressed hydrogen storage<adsorption <absorption<chemical hydrides Cleveland, 2008 3. Hydrogen generation from chemical hydrides Hydrogen storage system technologies , role of water in hydrolysis reaction are discussed MarreroAlfonso et al., 2009 17 12/12/2013 Copyright 2013-2014 1.
  • 18. Lit. Rev.... S.No Catalyst Observations References Rate kinetics studied, hydrolysis reaction Shang , with sodium borohydride was found to be 2006 is 1st order. 2. Co-B Hydrogen generation from NaBH4 using Jeong et al., Co- B catalyst. 2005 Co-B First order kinetics at low NaBH4 Dai et concentrations and zero order at high al.,2008 NaBH4 concentrations. 4. Cobalt (II) salts CoCl2 showed best performance in Akdim et hydrogen generation followed by al., 2009 Co(CH3OO)2>CoSO4>CoF2 5. Acid treated CoCl2/Al2O3 Best performance was observed by HCl Demirci, et and CH3COOH followed by citric acid> al.,2009 oxalic acid>sulphuric acid. 3. 18 12/12/2013 Copyright 2013-2014 1. Carbon supported ruthenium catalyst
  • 19. 19 12/12/2013 Copyright 2013-2014
  • 20. Chemicals  Sodium borohydride (NaBH4) powder with molecular weight of 37.8 g/mol and purity of 97%.  NaOH pellets having molecular weight 39.9 g/mol and purity of 97% . 20 12/12/2013 Copyright 2013-2014  Cobalt chloride (CoCl2) salt powder in hexa-hydrate form, having molecular weight 237.93 g/mol with a purity of 98%.
  • 21. Copyright 2013-2014 Schematic diagram of experimental setup 21 12/12/2013
  • 22. Copyright 2013-2014 Experimental Setup 22 12/12/2013
  • 23. 23 12/12/2013 Copyright 2013-2014
  • 24. Factors effecting the rate of hydrolysis reaction Temperature According to the hydrolysis reaction at concentration of NaBH4 equal to 0.55 g and CoCl2 concentration 0.06 g, rate of hydrogen generation increases with increase in temperature. 1200 1000 800 30 C 600 35 C 40 C 400 45 C 50 C Copyright 2013-2014 rate of hydrogen generation (ml/min) 1. 200 0 0 2 4 6 8 10 12 Time(min) 24 12/12/2013
  • 25. Continued… Rate constant with temperature can be expressed by Arrhenius equation k Ae E RT The values of E and A were estimated by substituting the k values at 45 o C and 63 C, where E = 37.931 kJ/mol and A = 12.54 Χ 108 sec-1. 25 12/12/2013 Copyright 2013-2014 E is the apparent activation energy, A is the pre exponential factor ,R is the universal gas constant, and T is the reaction temperature, K.
  • 26. Continued… 2. The Sodium Hydroxide (NaOH) Concentration  NaBH4 undergoes self hydrolysis and to suppress the self hydrolysis sodium hydroxide (NaOH)is added.  The excess amount of NaOH decreases the hydrogen yield. Copyright 2013-2014  Experimental results shows hydrogen generation rate decreases with increase NaOH concentration and temperature, at constant NaBH4 concentration and CoCl2 concentration. 26 12/12/2013
  • 27. Continued… The NaBH4 Concentration: The hydrogen generation rate increases with increase NaBH4 concentration with constant NaOH percentage. Hydrogen Molality of Temperature CoCl2 (g) NaOH (%) generation rate NaBH4(mol/kg) (oC) (ml/min) 1.19 0.05 45 0 300 1.45 0.06 45 0 480 1.71 0.07 45 0 520 1.98 0.08 45 0 600 1.19 0.05 55 0 320 1.45 0.06 55 0 420 1.71 0.07 55 0 480 1.98 0.08 55 0 560 1.19 0.05 63 0 340 1.45 0.06 63 0 480 1.71 0.07 63 0 560 1.98 0.08 63 0 620 27 12/12/2013 Copyright 2013-2014 3.
  • 28. Rate Kinetics  Rate increase with the increase of NaBH4 concentration at a fixed temperature and NaOH concentration. rH2 km NaBH4 where rH2 is the rate of hydrogen generation in milliliters per minute, mNaBH4 is the molality of NaBH4, and α is the apparent reaction order, k is proportionality constant. rH 2 1 1 k 1 w NaOH where , w NaOH is the concentration of NaOH in weight percent and k1 is a proportional constant. 28 12/12/2013 Copyright 2013-2014  Hydrogen generation rate decreased with the increase of NaOH concentration at a fixed NaBH4 concentration and temperature.
  • 29. Continued… Rate law of hydrogen generation from a basic NaBH4 solution can be expressed using equation , rH 2 km NaBH4 1 k 1 w NaOH Calculated order of the reaction (α) w.r.t NaBH4 concentration equals 1 with experimental error 0.2 and is shown in tabulated form on next slide. 29 12/12/2013 Copyright 2013-2014 The parameters k/ (1 + k1wNaOH) and α can then be determined by regressing the maximum hydrogen generation rate and the initial NaBH4 concentration.
  • 30. Parameters calculated at various temperature and NaOH concentrations NaOH concentration (%) k/ (1 + k1WNaOH) α (Reaction Order) 25 0 133.62 1.2 35 0 226.16 0.94 45 0 271.10 1.2 55 0 283.68 0.96 63 0 377.09 1 25 1 214.32 1 35 1 345.50 0.95 45 1 438.12 0.98 55 1 676.88 1 63 1 871.15 1 35 3 241.65 1.2 45 3 375.21 1.2 55 3 566.79 1.2 63 3 464.05 1 30 Copyright 2013-2014 Temperature ( C) 12/12/2013
  • 31. Calculation of the rate constants k and k1 1 rH 2 1 m NaBH4 k k 1 w NaOH k m NaBH4  Plot of 1/rH2 versus w NaOH /mNaBH4 gives a straight-line graph. Copyright 2013-2014  The intercept on the y axis is 1/kmNaBH4 and the slope is k1/k, from which both k and k1 may be determined. 31 12/12/2013
  • 32. Copyright 2013-2014 Calculations of the rate constants k and k1 Regression at 63oC and 1.45g of NaBH4 32 12/12/2013
  • 33. Parameters calculated at various temperatures and NaBH4 concentrations Temperature (o C) k (min-1) k1 (min-1) 1.19 35 192.30 0.02 1.19 45 555.55 0.13 1.19 63 1666.66 0.7 1.45 45 555.55 0.14 1.45 63 2000 0.8 1.71 35 740.74 0.4 1.71 45 769.23 0.6 1.71 63 2500 0.9 33 Copyright 2013-2014 Molality (mol/kg) 12/12/2013
  • 34. Hydrogen Gas Qualitative Analysis by Pop Test Copyright 2013-2014 Light a wooden splint and then hold it to area that contain hydrogen, a squeaky pop is observed if hydrogen is present. 34 12/12/2013
  • 35. Hydrogen gas quantitative analysis by gas chromatography AIMIL-NUCON Gas Chromatograph The Test shows the Purity of 85% with rest being nitrogen from air as per recovery basis from the sample. 35 12/12/2013 Copyright 2013-2014 A quantitative analysis test was conducted for hydrogen gas by Gas Chromatography, from Sophisticated Analytical Instrument Laboratory, Thapar University Patiala.
  • 36. Residual analysis Scanning Electron Microscope (SEM): SEM was performed for the residual substance from Sophisticated Analytical Instrument Laboratory, Thapar University Patiala. Copyright 2013-2014 1. Residue analysis by SEM 36 12/12/2013
  • 37. Continued… Copyright 2013-2014 2. Energy Dispersive Electron Microscopy (EDAX): EDAX was performed in Sophisticated Analytical Instrument Laboratory, Thapar University Patiala. It shows the presence of Sodium (Na), Cobalt (Co), Chlorine (Cl), Oxygen (O). 37 12/12/2013
  • 38. CONCLUSIONS  Hydrolysis reaction of sodium borohydride with cobalt chloride as catalyst is a first order reaction.  Hydrogen generation rate increases with increase in temperature, sodium borohydride (NaBH4) concentration and decreases with sodium hydroxide (NaOH) concentration. Copyright 2013-2014  The rate constant ‘k’ with respect to sodium borohydride increased significantly from 555.50 min-1 to 1666.40 min-1 when the temperature increased from 45 to 63 C. However, rate constant ‘k1’ with respect to sodium hydroxide did not change significantly with NaBH4 concentration and temperature. 38 12/12/2013
  • 39. Continued…  The gas chromatography analysis indicates, the hydrogen gas purity is 85% and rest is nitrogen. The tendency of sodium borohydride to store and release hydrogen is more effective and favorable. Copyright 2013-2014  The hydrogen generation rates are observed to be higher from hydrolysis studies of alumina nanoparticles - NaBH4 - CoCl2 system as compared to NaBH4 - CoCl2 systems. 39 12/12/2013
  • 40. References 1. Shang, Y. and Chen, R., Semiempirical Hydrogen Generation Model Using Concentrated Sodium Borohydride Solution, J. Energy & Fuels, Vol. 20, No. 5, 2006, pp. 2149-2154. 2. Ying, W., Hydrogen Storage via Sodium Borohydride, Presented by Stanford University, 2003. 3. Liu, R.S.; Lai, H.C.; Bagkar, N.C.; Kuo, H.T.; Chen, H.N.; Lee, J.F.; Chung, H.J.; Chang, S.M.; and Weng, B.J., Investigation on Mechanism of Catalysis by Pt-LiCoO2 for Hydrolysis of Sodium Borohydride Using X-ray Absorption, J. Phys. Chem. B , Vol. 112, No. 16,2008 pp. 4870-4875. 5. Shang, Y. and Chen, R., Hydrogen Storage via the Hydrolysis of NaBH4 Basic Solution, Optimization of NaBH4 Concentration, Energy & Fuels, Vol. 20, No. 5, 2006, pp.2142-2148. Copyright 2013-2014 4. Marrero-Alfonso, E.Y.; Beaird, A.M.; Davis, T.A.; Matthews, M.A., Hydrogen Generation from Chemical Hydrides, Ind. Eng. Chem. Res., Vol.48, No.8,2009 pp.37033712.
  • 41. Continued... 6. Cleveland, C.J., Hydrogen storage, Encyclopaedia of Earth, 2008. 7. Klanchar, M.; Hughes, T.G.; Gruber, P., Attaining DOE Hydrogen storage Goals with Chemical Hydrides, Applied Research Laboratory, The Pennsylvania State University, 2003. 8. Klanchar, M.; Lloyd, C.L.; Compact Hydrogen Generating Systems Based on Chemical Sources for Low and High Power Applications, Proceedings of the 39th Power Sources Conference, 2000, pp. 188-191. 10. Wu, Y., Process for the Regeneration of Sodium Borate to Sodium Borohydride for Use as a Hydrogen Storage Source, New FY 2004 Project, U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, FY 2003 Progress Report for Hydrogen, Fuel Cells, and Infrastructure Technologies Program, October 2003. Copyright 2013-2014 9. McClaine, A.W., Chemical Hydride Slurry for Hydrogen Production and Storage, New FY 2004 Project, U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, FY 2003 Progress Report for Hydrogen, Fuel Cells, and Infrastructure Technologies Program, October 2003.
  • 42. Continued... 11. Hydrogen, Fuel Cells & Infrastructure Technologies Program Multi- Year Research, Development and Demonstration Plan, Department of Energy, Washington D.C., 2005. 12. Zuttel, A., Hydrogen Storage Methods, Springer-Verlag, Vol. 91, No. 4, 2004, pp. 157–172. 13. Aggrawal, R.; Offutt, M.R.; Ramage, M.P., Hydrogen Economy and Opportunity for Chemical Engineers, AIChE journal,Vol.51, No. 6, 2005, pp. 1582–1589. 14. Kennedy, D., The Hydrogen Solution Science, Journal of American Chemical Society, Vol. 305, No.5686, 2004, pp.917. 15. Ritter, J.; Ebner, A.; Wang, A.D.; Zidan, J., Implementing a Hydrogen Economy, Journal of Physical Chemistry, Vol.6, No. 9, 2003, pp.18–23. 16. Othmer, K., Encyclopedia of Chemical Technology, 4th ed., Vol. 13, pp. 606-629, New York 1991. pp. 18. Shang, Y. and Chen, R., Hydrogen Storage via the Hydrolysis of NaBH4 Basic Solution: Optimization of NaBH4 Concentration, Energy &Fuels, Vol.20, No.5, 2006, pp. 2142–2148. 11. www.eia.gov Copyright 2013-2014 17. James, B.D.; Wallbridge, G.H., Metal Tetrahydroborates, Prog. Inorg. Chem, Vol. 11, 1970, 99–231.
  • 43. Acknowledgements Copyright 2013-2014 The authors gratefully acknowledge the support provided by management of Thapar University, Patiala and Thapar Centre for Industrial Research and Development, Patiala, India, for providing the necessary facilities to carry out this research work. 43 12/12/2013
  • 44. 44 12/12/2013 Copyright 2013-2014
  • 45. 45 12/12/2013 Copyright 2013-2014