Dipl. Ing. Matthias Mayerhofer Technische Universität München ...

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52 Results and Discussion Figure 24: SEM image of Used Catalyst, grey particles Figure 25: SEM of Used Catalyst, black particles
Results and Discussion 53 7.2 Sampling and Gas Analysis The product gas was online monitored in order to determine its composition at different operating conditions. The sampling point was after the catalyst bed, in order to have a clear picture of how it is affected by the presence of the catalyst. With the results of these measurements further values were calculated to define the potentials of the syngas. The compounds that were measured were CO, CH4 and H2 which constitute the fuel of the product gas and of course the CO2 and the water content. The gas yield before the throughput of the gas in the catalyst bed can be seen below Figure 26. After the decomposition of the tar inside the catalyst bed the composition changes significantly. 24,5 11,8 5,7 11,0 Figure 26: Gas composition before catalyst test rig Dry product gas Lower Heating Value (LHV) was calculated for the different operating conditions. The results can be seen below in Table 6, Table 7 and Table 8. For the iron based catalysts, it can be seen that as the temperature increases the heating of the value increases too, whereas as the space velocity increases the heating value decreases. This is expected as the temperature and the residence time of the gas in the catalyst are two essential factors that define the value of the product gas. The higher the activity of the reactions that take place the higher the richness of the gas composition in H2, CH4, and CO. For the iron based catalysts, the highest heating value of the gas is obtained at 860°C and SV=6584 1/h. But this value is very close to the one obtained for 800°C and SV=4488 1/h, which is important as these catalysts are supposed to be used in situ were the maximum temperature reached is 800°C. For the nickel based catalysts, the LHV is slightly affected by the changes in the SV. These catalysts were sufficiently active in all the different operating conditions, so the differences in the residence time didn’t affect a lot the gas composition. For the precious metal catalysts the influence of the SV is not very evident either. The LHV of these two catalysts don’t differ a lot but the products gas in their presence has significantly higher heating value compared to the iron ones. To calculate the LHV first the wet concentration of every compound was found with the following equation Then taking into consideration the molar mass of every compound and its heating value the LHV was calculated, and the results can be seen below. It is obvious that although the operating conditions vary significantly the heating value of the gas didn’t range a lot, because the composition of the gas was affected enough by the presence of the catalyst. 4,0 42,9 H₂O CH₄ CO CO₂ H₂ N₂
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Betreuer der Arbeit: Dipl. Ing. Mat
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Acknowledgements This work was acco
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II Content Content Acknowledgements
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IV List of Figures List of Figures
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VI List of Abbreviations List of Ab
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VIII Notation Notation ΔH [Kj/mol]
Page 17 and 18: Introduction 1 1 Introduction The d
Page 19 and 20: Introduction 3 1.2 Tasks The presen
Page 21 and 22: Biomass Gasification 5 2 Biomass Ga
Page 23 and 24: Biomass Gasification 7 Spouted Bed
Page 25 and 26: Biomass Gasification 9 2.2 Gas Clea
Page 27 and 28: Biomass Gasification 11 types of ca
Page 29 and 30: Biomass Gasification 13 Mechanical
Page 31 and 32: Biomass Gasification 15 Partial oxi
Page 33 and 34: Biomass Gasification 17 The followi
Page 35 and 36: Biomass Gasification 19 Groups of C
Page 37 and 38: Nickel Based Catalysts 21 even show
Page 39 and 40: Nickel Based Catalysts 23 The conte
Page 41 and 42: Nickel Based Catalysts 25 ing press
Page 43 and 44: Nickel Based Catalysts 27 3.4 Proce
Page 45 and 46: Iron Based Catalysts 29 4 Iron Base
Page 47 and 48: Iron Based Catalysts 31 Measurement
Page 49 and 50: Iron Based Catalysts 33 The percent
Page 51 and 52: Iron Based Catalysts 35 4.6 Catalys
Page 53 and 54: Iron Based Catalysts 37 Reduction i
Page 55 and 56: Iron Based Catalysts 39 and MgO (Di
Page 57 and 58: Precious Metal Catalysts 41 5 Preci
Page 59 and 60: Precious Metal Catalysts 43 Bimetal
Page 61 and 62: Experiments 45 Table 3: Biomass fee
Page 63 and 64: Experiments 47 6.3.1Experimental Pr
Page 65 and 66: Experiments 49 6.3.2 Tar Sampling M
Page 67: Results and Discussion 51 7 Results
Page 71 and 72: Results and Discussion 55 Wet Gas C
Page 73 and 74: Results and Discussion 57 er, the v
Page 75 and 76: Results and Discussion 59 7.3.1. Ef
Page 77 and 78: Results and Discussion 61 The conve
Page 79 and 80: Results and Discussion 63 7.3.3 App
Page 81 and 82: Results and Discussion 65 7.4 Blank
Page 83 and 84: Summary/Outlook 67 The aim is to pr
Page 85 and 86: References 69 (Aznar,1993) Aznar, M
Page 87 and 88: References 71 (Hepola,1997b) Hepola
Page 89 and 90: References 73 (Sarvaramini,2012) Sa
Page 91 and 92: 75 Appendix Appendix A: Iron based
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Dipl. Ing. Matthias Mayerhofer Technische Universität München ...

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