Etude de la combustion de gaz de synthèse issus d'un processus de ...

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Chapter 2 A third type of FB is currently being developed, termed a fast, internally circulating gasifier, which combines the design features of the other two types. The reactor is still at the pilot-stage of development (McKendry, 2002a). Bubbling fluidized bed (BFB) Bubbling FB gasifiers consist of a vessel with a grate at the bottom through which air is introduced. Above the grate is the moving bed of fine-grained material into which the prepared biomass feed is introduced. Regulation of the bed temperature to 700–900º C is maintained by controlling the air/biomass ratio. The biomass is pyrolysed in the hot bed to form a char with gaseous compounds, the high molecular weight compounds being cracked by contact with the hot bed material, giving a product gas with a low tar content, typically
Bibliographic revision Circulating Fluidized bed (CFB) Circulating FB gasifiers are able to cope with high capacity throughputs and are used in the paper industry for the gasification of bark and other forestry residues. The bed material is circulated between the reaction vessel and a cyclone separator, where the ash is removed and the bed material and char returned to the reaction vessel. Gasifiers can be operated at elevated pressures, the advantage being for those end-use applications where the gas is required to be compressed afterwards, as in a gas turbine. Gas + contaminants Gas Cyclone Fluidized bed tel-00623090, version 1 - 13 Sep 2011 Biomass Grate Ashes Oxidant speed 5-10 m.s -1 Tar + inert Figure 2.6 - Circulating fluidized bed gasifier The advantages of such gasifier are (Bridgwater and Evans, 1993): - Suitable for rapid reactions; - High heat transport rates possible due to high heat capacity of bed material; - High conversion rates possible with low tar and unconverted carbon. . The disadvantages are (Bridgwater and Evans, 1993): - Temperature gradients occur in direction of the solid flow; - Size of fuel particles determine minimum transport velocity; high velocities may result in equipment erosion; - Heat transfer less efficient than bubbling fluidized bed. 28
Page 1 and 2: THÈSE Pour l’obtention du Grade
Page 3 and 4: Acknowledgements Acknowledgements T
Page 5 and 6: Résumé __________________________
Page 7 and 8: Nomenclature Nomenclature Roman tel
Page 9 and 10: Nomenclature Subscripts tel-0062309
Page 11 and 12: Contents tel-00623090, version 1 -
Page 13 and 14: Contents 6.4. SYNGAS FUELLED-ENGINE
Page 15 and 16: Introduction CHAPTER 1 INTRODUCTION
Page 17 and 18: Introduction proves to have higher
Page 19 and 20: Introduction Chapter 3 - Experiment
Page 21 and 22: Bibliographic revision CHAPTER 2 BI
Page 23 and 24: Bibliographic revision point today
Page 25 and 26: Bibliographic revision - Boudouard
Page 27 and 28: Bibliographic revision Table 2.1 -
Page 29: Bibliographic revision Biomass Dryi
Page 33 and 34: Bibliographic revision or eliminate
Page 35 and 36: Bibliographic revision established
Page 37 and 38: Bibliographic revision Hydrogen Hyd
Page 39 and 40: Bibliographic revision of low moist
Page 41 and 42: Bibliographic revision scrubbing an
Page 43 and 44: Bibliographic revision suggests tha
Page 45 and 46: Bibliographic revision 1 d( δ A) 1
Page 47 and 48: Bibliographic revision Since n is
Page 49 and 50: Bibliographic revision 2 ( rsr ) 2
Page 51 and 52: Bibliographic revision This evoluti
Page 53 and 54: Bibliographic revision The burning
Page 55 and 56: Bibliographic revision δVG = − a
Page 57 and 58: Bibliographic revision 2 1 − −
Page 59 and 60: Bibliographic revision where the su
Page 61 and 62: Bibliographic revision the stretche
Page 63 and 64: Bibliographic revision burning velo
Page 65 and 66: Experimental set ups and diagnostic
Page 81 and 82:
Experimental set ups and diagnostic
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Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Chapter 4 CHAPTER 4 EXPERIMENTAL AN
Page 91 and 92:
Chapter 4 4.1 Laminar burning veloc
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Chapter 4 4.1.1.1 Flame morphology
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Chapter 4 P i = 1.0 bar, Ti = 293 K
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Chapter 4 Figure 4.5 shows schliere
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Chapter 4 P i = 2.0 bar, T i = 293
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Chapter 4 Sn (m/s) 3.0 2.5 2.0 1.5
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Chapter 4 5 ms 10 ms 15 ms 20 ms 25
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Chapter 4 behaviour of the curves r
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Chapter 4 1.50 Sn (m/s) 1.25 1.00 0
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Chapter 4 0.5 0.4 φ =1.0 Su (m/s)
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Chapter 4 variation of the normaliz
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Chapter 4 4.1.1.6 Comparison with o
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Chapter 4 The values of laminar bur
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Chapter 4 Pressure (bar) 7 6 5 4 3
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Chapter 4 0.5 0.4 φ=1.2 Su (m/s) 0
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Chapter 4 0.3 φ=0.8 Su (m/s) 0.2 0
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Chapter 4 a minimum pressure to exp
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Chapter 4 Notice the similar behavi
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Chapter 4 A very good agreement bet
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Chapter 4 ( ) Q = h T − T (4.21)
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Chapter 4 tel-00623090, version 1 -
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Chapter 4 are tested and discussed.
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Chapter 4 7 500 Pressure (bar) 6 5
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Chapter 4 Pressure (bar) 7 6 5 4 3
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Chapter 4 4.2.3.4 Quenching distanc
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Chapter 4 10000 Quenching distance
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Chapter 5 CHAPTER 5 EXPERIMENTAL ST
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Chapter 5 30 10 25 8 Pressure (bar)
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Chapter 5 30 Piston position (mm) 2
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Chapter 5 5.1.1.4 In-cylinder press
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Chapter 5 estimation of various par
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Chapter 5 TDC 1.25 ms 2.5 ms 3.75 m
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Chapter 5 Piston position (mm) 500
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Page 159 and 160:
Chapter 5 From figure 5.15 is possi
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Chapter 5 From figure 5.16 is obser
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Chapter 5 80 Pressure (bar) 70 60 5
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Chapter 5 80 10 Pmax (bar) 70 60 50
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Chapter 5 -5.0 ms -3.75 ms -2.5 ms
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Chapter 5 observation emphasis the
Page 171 and 172:
Chapter 6 CHAPTER 6 NUMERICAL SIMUL
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Chapter 6 centered at the spark plu
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Chapter 6 H 2 O, (3) N 2 , (4) O 2
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Chapter 6 For all the above express
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Chapter 6 motions within the cylind
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Page 183 and 184:
Chapter 6 Heat transfer Wei et al.,
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Chapter 6 The calibration coefficie
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Chapter 6 6.3.2.2 In-cylinder volum
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Chapter 6 40 Experimental 30 Numeri
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Chapter 6 80 70 60 Numerical Experi
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Chapter 6 downdraft syngas than for
Page 195 and 196:
Chapter 6 80 23º BTDC 60 29.5º BT
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Chapter 6 with experimental results
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Conclusions CHAPTER 7 CONCLUSIONS 7
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Conclusions radius and time for syn
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Conclusions conditions, therefore s
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Conclusions tel-00623090, version 1
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References References tel-00623090,
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References tel-00623090, version 1
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Appendix A - Overdetermined linear
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Appendix A - Overdetermined linear
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Appendix B- Syngas-air mixtures pro
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Appendix C -Rivère model Heat flux
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Appendix C -Rivère model The work
Page 231 and 232:
tel-00623090, version 1 - 13 Sep 20
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