1. Development of a Laboratory ScaleReactor Facility to Generate HydrogenRich Syngas via ThermochemicalEnergy ConversionMandeep SharmaMasters Candidate, Mechanical EngineeringLouisiana State University

2. 2Outline Objective Background Information Conical Spouted Bed (CSB) Reactor Thermochemical Energy conversion Cold Flow Hydrodynamic Studies Thermodynamic Equilibrium Analysis Experimental Results for Homogeneous Fuel Reforming Preliminary Study for Heterogeneous Fuel Reforming Conclusions Recommendations and Future Work Acknowledgement

3. 3Objective To develop a laboratory scale CSB reactor facility for the purpose of producing H2 rich synthesis gas from sustainable hydrocarbon fuels and various biomass wastes* via thermochemical routes of gasification /reforming.H2 rich synthesis gas (Syngas) mainly consists of H2 and CO, and traces of CO2, H2O and lower hydrocarbons. Clean H2 rich syngas has applications in fuel cells, gas turbines and engines for clean and efficient power generation. Validation tests with Propane , Long term biomass waste : Glycerol*

4. 4Fuel SelectionGlycerol (C3H8O3): (long term fuel) byproduct of biodiesel production, has been considered an excellent candidate for H2 production. For every 9 kg of biodiesel produced, about 1 kg of a crude glycerol by-product is formed. Only in the US, biodiesel production has increased dramatically from 500,000 gallons in 1999 to 70 million gallons in 2005 [1].Propane (C3H8): (used in present study) High potential as hydrogen carrier for future power applications [2]. More stored energy per unit volume and thus releases more heat compared to methane. higher boiling point (-42 C) than methane (-164 C), so it can be liquefied even at low pressures i.e. at 9 bar, and hence is easier to store and transport. [1]. National Biodiesel Board, 2006. [2]. G. Kolb, R. Zapf, V Hessel, and H. Lowe. Propane steam reforming in micro-channels: Results from catalyst screening . and optimization. Applied Catalysis A: General, 277:155166, 2004.

5. 5Background Introduction

6. 6Conical Spouted Bed (CSB) Reactor Mathur and Gishler initially introduced spouted beds in 1954 as an alternative method for drying moist wheat grains. Recent applications include pyrolysis of solid wastes, e.g. rice husk, sawdust, plastic wastes, scrap tires, etc. Potential for syngas generation from biomass wastes (glycerol) and hydrocarbon fuels.Advantages of CSB reactor Perfect mixing Very efficient heat transfer because of cyclic movement Very short residence time Suitable for sticky, moist, irregular shaped bed material

7. 7 CSB Concept Contacting of solids with fluid by injecting a steady axial jet of fluidizing medium (air/N2/steam).Schematic of CSB actual reactor model Spouting behavior of CSB cold flow model The jet entrains particles, which are carried through the central spout, forming a fountain before being deposited in an annular region. This mechanism creates a regular circulation pattern of particles through the bed.

8. 8Thermochemical ConversionAt operating conditions, chemical reaction occurs that producesynthesis gas or syngas , a mixture of predominantly H2 and CO.

9. 9 ContdA thermochemical conversion of hydrocarbon fuel, propane,into syngas involves four main types of fuel reforming routes:Dry Reforming (DR): (endothermic)fuel(C3H8) a H2 + other HCs (...CH4, C2H2, C2H6, etc.) + c CPartial Oxidation (POX): (exothermic)C3H8 + 3O2 + nN2 9/4 H2 + CO + CO2 + CH4 + 3/2H2O + 3n N2Steam Reforming (SR): (endothermic)C3H8 + 3H2O 7 H2 + 3COAutothermal Reforming (ATR): (endoth., exoth., thermo-neutral)C3H8 + 3O2 +3H2O + nN2 CH4 + CO + CO2 + 2H2 + 3H2O + 3n N2

10. 10Cold Flow Hydrodynamic Study

11. 11 Cold flow studies were conducted to establish stable spouting range. Stable spouting occurs over a specific range of gas velocity called min. spouting velocity (ums). Different Spouting RegimesKnowledge of (ums) is of fundamental importance in the design and operation ofspouted beds. ums is the minimum gas velocity needed to maintain spoutingoperation.

12. 12CSB Cold Flow SetupExperiments were carried out at atmosphericconditions using Alumina powder (=3960 Kg/m3)as bed material and air as spouting gas. Schematic of experimental set-up: (1) air manifold, (2) air filter (3), control valve, (4/5) rotameters, (6) air inlet pipe, (7/8) pressure taps at bed inlet and outlet, (9) U-tube manometer, (10) conical contactor, (11) bed material, and (12) cylindrical column.

13. 13Experiment Summary of operating parameters tested * ** Indicates the best set of testing parameters which shows uniform cyclic behavior of CSB.

14. 14Effect of System Parameters on (ums)o Effect of different Ho, Do and dp on (ums)o

15. 15 Evaluation of all existing correlations for (ums)o Source Correlation Eqn.Markowski (1)(1983)Choi (1992) (2)Gorshtein (3)(1964)Mukhlenov (4)(1965)Tsvik (1967) (5)Olazar (1992) (6)Olazar (1996) (7)Bi (1997) (for (8)Db/Do 1.66) They used CSBs which were significantly larger than the model investigated in present study. In theory, predictions should match experimental data, i.e. the best performing correlations will align with the diagonal line.

16. 16Evaluation of Correlations (contd)Correlations predictions comparison with experimental resultsfor a particular set of operating parameters

17. 17Poor performance of correlations:

18. 18Proposed Correlation Proposed correlation shows excellent agreement with experiments 75 o Present Study, 60 cone angle 70 + 16.3 % 0.483 mm dp, 6.350 mm Do 65 0.483 mm dp, 4.572 mm Do 60 0.483 mm dp, 3.302 mm Do 55 1.092 mm dp, 6.350 mm Do Predicted (ums)o, m/s 50 1.092 mm dp, 4.572 mm Do - 17.15 % 45 1.092 mm dp, 3.302 mm Do 40 35 30 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 Experimental (ums)o, m/s

19. 19Summary (Cold Flow Studies) Available correlations for calculating min. spouting velocity have shortcomings for small-sized laboratory scale CSB studies. Developed Simple empirical correlation for (ums)o which showed excellent agreement with experimental findings. Cold flow hydrodynamic study provides a foundation for design of hot flow CSB reactor facility. Hot flow tests are also needed to carefully examine the stable spouting at high temperatures.

20. 20Thermodynamic Equilibrium Analysis

21. 21 I. Thermodynamic Equilibrium Analysis Used as reference tool to qualitatively choose operating conditions such as pressure, temperature and reactants feed ratio irrespective of reaction kinetics, reactor design and operation. Used for assessment of homogeneous (non-catalytic) DR, POX, SR and ATR of propane. Canteras chemical equilibrium solver (Goodwin 2009), which involves nonstoichiometric approach (element potential method), is used. GRI-Mech 3.0*, (53 species) and solid carbon databases are used to evaluate the thermodynamic properties of the chemical species considered in the model. The initial amount of propane is assumed to be 1 mol.*G. P. Smith, D. M. Golden, M. Frenklach, N. W. Moriarty, B. Eiteneer, M. Goldenberg, C. T. Bowman, R. K. Hanson, S. Song, Jr. W. C. Gardiner, V. V. Lissianski, and Z. Qin. GRI-Mech 3.0. http://www.me.berkeley.edu/gri_mech/version30/, 1999.

22. 22 Pressure and Temperature Selection Low pressures favors H2 production. 1 atm pressure is selected throughout present study. High pressure experiments can be expensive and dangerous.

23. 23Reactants Feed Ratio Selectiona) Homogeneous DR: 2 cases of CPRs 10 and 24 are takenPropane cracking reactions: C3H8 4H2 + 3C and CH4 2H2 + C

24. 24Reactants Feed Ratio Selection Contda) Homogeneous POX: Propane + Air + Nitrogenb) Homogeneous SR: Propane + Steam + Nitrogenc) Homogeneous ATR: Propane + Steam + (Air + Nitrogen)Ternary Diagram?

25. 25Ternary Diagram ContdA ternary system diagram, also known as Gibbs triangle,graphically represents the ratios of three variables aspositions in an equilateral triangle. Three variables (concentrations here) conveniently plotted in a two- dimensional graph. Any point within this triangle represents the overall composition (100%) of a ternary system at a fixed temperature and pressure.

26. 26Ternary Diagram Contd 2. 25% A, 40% B, 35% C and their sum is 100%. *In present study, ternary system diagram is used as a convenient way to decide an optimum ratios of reactants mixture for SR, POX and ATR.

27. 27Homogeneous POX Carbon Mole Fraction T = Tad - TR

28. 28Homogeneous POX Contd H2 Mole Fraction CO Mole Fraction

29. 29Homogeneous SR Carbon Mole Fraction T = Tad - TR

30. 30Homogeneous SR Contd H2 Mole Fraction CO Mole Fraction

31. 31Homogeneous ATR Carbon Mole Fraction T = Tad - TR

32. 32Homogeneous ATR Contd H2 Mole Fraction CO Mole Fraction

33. 33 Operating Parameters Selection SummaryCPR : Carrier to Propane gas ratio, APR : Air to Propane gas ratio, WPR : Water to Propane ratio, : Equivalence ratio = (F/A) / (F/A)stoic

34. 34Homogeneous Reforming Comparisons H2 the order of H2 production: ATR >SR >POX >DR

35. 35 Contd CO

36. 36 Contd C carbon formation increasing order: ATR< SR< POX< DR

37. 37 Efficiencies Comparisons at 1 atm and 1000C*Reactants feed ratios are discussed in slide 32.

38. 38Summary (Thermodynamic Equilibrium Analysis) Lower pressure favors hydrogen production. Temperature range selected for performing homogeneous DR, POX, SR and ATR is 600 ~ 1000C. Used as a reference tool to select optimum reactants feed ratios for carbon free reactions without harming the reaction system. A homogeneous ATR is most efficient to produce. Qualitatively choose operating conditions such as pressure, temperature, reactants feed ratios irrespective of reactor design, reaction kinetics and operation. It uses idealized thermodynamic state with maximum entropy which requires infinite residence time for all chemical reactions to complete, which in actual practice it is not feasible. Therefore, experimental tests for homogeneous processes are required for quantitative analysis.

39. 39 Experimental Results forHomogeneous Fuel Reforming

40. 40 Experimental Setup Schematic Diagram*A simpler plug flow reactor system in experimental investigations is meant toprovide preliminary results that are used to evaluate different reformingapproaches, which will eventually be applied in a CSB reactor in the third phase

41. 41Results: I. Exhaust Gas Composition a) Homogeneous DR:

42. 42 Contdb) Homogeneous POX:

43. 43 Contdc) Homogeneous SR:

44. 44 Contdd) Homogeneous ATR:

45. 45II. Homogeneous Processes Performance Evaluation a) C3H8 Conversion Efficiency:

46. 46 Contdb) H2 Production Efficiency: Thermodynamic Equilibrium Experiment

47. 47 Contdb) CO Production Efficiency: Thermodynamic Equilibrium Experiment

48. 48Summary (Experiments) ATR is most suitable whereas DR is least suitable for not only producing hydrogen rich syngas but also in terms of clean and carbon free process. The experiment tests, however, provides similar trends compared to thermodynamic equilibrium in terms of major syngas species, propane conversion, H2 and CO production efficiencies. The difference between theoretical qualitative predictions and experiment quantitative results is attributed to inclusion of solid carbon in product stream in the thermodynamic equilibrium analysis whereas the carbon in actual tests is converted to ethane and acetylene. Homogeneous reforming processes requires temperature more than 700C to break down into lower hydrocarbon species if no catalysts are used.

49. 49 Preliminary Studies forHeterogeneous Fuel Reforming

50. 50Literature Review a) Catalyst Selection Very limited resources are available for non-noble metal based catalysts favoring heterogeneous fuel reforming. In literature, the order of catalysts (both noble and non-noble) reactivity for DR and SR of propane is Ru > Rh > Ni > Pt > Pd. Due to low cost and ready availability of nickel (Ni) metal, the supported Ni metal-based catalyst is the preferred choice for the present investigation of heterogeneous fuel reforming. Bare Ni is not sufficient as a catalyst for fuel reforming applications, because of its deactivation and coke formation issues at high temperatures.

51. 51 Contd b) Catalyst Support Selection Catalyst support is a material, usually a solid with a high surface area, to which the catalyst is affixed. Typically supports are inert which include various kinds of carbon, alumina, and silica. In the present study, alumina (Al2O3) is selected as catalyst support, since it causes higher syngas production as compared to other supports i.e. MgO , CaO etc. c) Additive Promoter Selection Ni/Al2O3 catalysts performance in terms of its reactivity, stability and coke resistance can be improved either by making strong metal- support interaction, addition of CeO2 into Ni/support catalyst, or by using smaller Ni particle size and its higher dispersion.

52. 52 Contd Nickelous aluminum oxide (Ni/Al2O3) is selected as non-noble base catalyst than precious metals whereas cerium oxide (CeO2) is selected as an additive promoter in the present thesis. For preliminary studies, 15 wt% cerium oxide doped in 10 wt% Ni/Al2O3 catalyst is used for heterogeneous ATR. some of the results appeared as expected, but a significant different behavior of heterog- eneous ATR than homogeneous cases is observed. Reason? Need more study on it. Can improve? Yes, by testing Tested under same operating conditions as were used in homogeneous ATR. catalysts with multiple compositions.

53. 53Thesis Conclusions

54. 54 The thesis provides data needed for development of conical spouted bed (CSB) reactor for the purpose of producing hydrogen rich syngas. Cold flow hydrodynamic study provides a foundation for design of hot flow CSB reactor facility. Developed Simple empirical correlation for (ums)o showed excellent agreement with experimental findings. The selection of operating conditions for experiments reactants feed ratio, pressure and temperature is guided by results from thermodynamic equilibrium (TE). TE and experimental results reveal that the homogeneous ATR is most efficient and DR is least efficient in terms of syngas production. The difference between theoretical qualitative predictions and experiment quantitative results is attributed to inclusion of solid carbon in product stream in TE whereas the carbon in actual tests is converted to ethane and acetylene.

55. 55 Propane in homogeneous reforming processes requires temperature more than 700C to break down into lower hydrocarbon species if no catalysts are used.

56. 56Recommendations and Future Work

57. 57Cold Flow Hydrodynamic Studies:Additional tests using varying particle densities and cone angles arerequired for the development of a universally applicable correlation for Ums.A data reduction in pressure drop and flow rates measurements can beimproved by using DAQ system.Heterogeneous Reforming:More catalyst samples of different CeO2 and Ni loadings on Al2O3 metalsupport need to be prepared and tested to access the detailedcharacterization of catalysts performance for heterogeneous DR, POX, SRand ATR processes.Construction of Bench Top CSB reactor:third phase of CSB reactor facility eventually involves the construction of abench top laboratory scale CSB for the follow-up research where similartests need to be performed.

58. 58Construction of Bench Top CSB reactor Proposed geometry for CSB reactor system

59. 59Questions?Acknowledgements:1. Advisor, Dr. Ingmar Schoegl and Committee, Dr. Ram Devireddy and Dr. Ying Wang2. Louisiana State University Council on Research Faculty Research Grant Program3. Research Group: Avishek, Mohsen, Khurshida, Joseph, Matthew and Joe4. Zianqing Zhao, graduate student of Dr. Wangs research group5. Friends and Family

60. 60Backup Slides

61. 61Cold Flow Studies

62. 62Evolution of Spouting regimes

63. 63 Evaluation of CorrelationsFor one particular data set - e.g. 60, 483 m, 6.35 mm Do best performing correlations align with the diagonal line

64. 64Evaluation of Correlations contd Comparison of Gorshtein correlation for all data sets

65. 65Evaluation of Correlations contd Comparison of Mukhlenov correlation for all data sets

66. 66Evaluation of Correlations contd Comparison of Tsvik correlation for all data sets

67. 67Evaluation of Correlations contd Comparison of Choi correlation for all data sets

68. 68Pressure Drop Measurements Effects of Ho and Do on stable pressure drops and maximum pressure drops

69. 69Thermodynamic Equilibrium Studies

70. 70Homogeneous DR: (Thermodynamic Equilibrium) Product Species Mole Fractions

71. 71Homogeneous POX: (Thermodynamic Equilibrium) Product Species Mole Fractions

72. 72Homogeneous SR: (Thermodynamic Equilibrium) Product Species Mole Fractions

73. 73Homogeneous ATR: (Thermodynamic Equilibrium) Product Species Mole Fractions

74. 74ADVANTAGES OF FLUIDIZED BED Rapid mixing of solids, uniform temperature andconcentrations. Applicable for large or small scale operations. Heat and mass transfer rates between gas and particlesare high as compared to other modes of contacting. There is no moving part and hence a fluidized bed reactoris not mechanically agitated reactor. So, maintenance cost can be low. The reactor is mounted vertically and save space.The beds have a static pressure head due to gravity, given by 0gh,