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

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Chapter 2 2.3.1 Influence of biomass type In large samples there is a relatively constant atomic ratio of C 10 H 14 O 6 for all biomass kinds (Reed and Das, 1988). A direct link between the chemical composition of biomass and gas obtained by gasification exists. Table 2.4 shows experimental values of the chemical composition of syngas for different types of biomass in a downdraft gasifier. tel-00623090, version 1 - 13 Sep 2011 Table 2.4 - Characteristics of syngas by biomass type Gas produced (mol/kg) HHV Residues H (MJ/m 3 2 CO CO 2 CH 4 C 2 H 2 C 2 H 4 C 2 H 6 ) Rice husk (a) 0.00236 0.00651 0.00717 0.00209 6.2×10 -5 7.6×10 -4 1.1×10 -4 11.11 Nut shell (a) 0.00485 0.00788 0.00477 0.00293 4.9×10 -5 6.1×10 -4 2.1×10 -4 14.55 Pine (a) 0.00529 0.00722 0.00505 0.00272 1.2×10 -4 8.1×10 -4 1.7×10 -5 14.68 Eucalyptus (a) 0.00275 0.00712 0.00380 0.00316 2.6×10 -5 5.5×10 -4 1.5×10 -4 13.41 Vine Pruning (b) 0.0104 0.02378 - 0.00641 0.00199 8.8×10 -4 0.00121 11.41 Cherry Stone © 0.00639 0.00668 - 0.00371 0.00103 0.00217 0.00173 - a (Gañan et. al., 2005) ; b (Cuellar, 2003), c (González et al., 2003). As shown in Table 2.4 the influence of biomass type is not considerable. The highest heat value of the syngas obtained with pine and almond shell, being the lowest heat value obtained with husks. The woods in the Table 2.4 (pine and eucalyptus) are largely the most available biomass resource in Portugal (Ferreira et al., 2009) and therefore some special attention should be given to them. The main combustible components of wood are cellulose, hemicelluloses, and lignin, which are compounds of carbon, hydrogen, and oxygen. Other minor combustible components in wood are fats, resins, and waxes. The major non-combustible component of wood is water, which makes up to 50% of freshly cut wood. Though the ash content is low (
Bibliographic revision of low moisture content. After passing through a relatively simple cleanup train the gas can be used in internal combustion engines. 2.3.2. Influence of reactor type Dry wood was experimental used by several workers in different types of gasifiers being the results shown in Table 2.5. Some values are just indicative due to unknown gasification conditions. Table 2.5 – Characteristics of the produced gas for atmospheric gasifiers (Mehrling and Vierrath, 1989; Graham and Bain, 1993; Hasler et. al., 1994; Hasler and Nussbaumer, 1999) tel-00623090, version 1 - 13 Sep 2011 Property Downdraft Updraft BFB CFB Tar (mg/Nm 3 ) 10-6000 10000-150000 Not defined 2000 – 30000 Particules (mg/Nm 3 ) 100-8000 100-3000 Not defined 8000-100000 LHV (MJ/Nm 3 ) 4.0 – 5.6 3.7 – 5.1 3.7 – 8.4 3.6 – 5.9 H 2 (vol%) 15-21 10-14 5 – 16.3 15-22 CO (vol%) 10-22 15-20 9.9 – 22.4 13-15 CO 2 (vol%) 11-13 8-10 9 – 19.4 13-15 CH 4 (vol%) 1-5 2-3 2.2 – 6.2 2-4 C n H m (vol%) 0.5 -2 Not defined 0.2 – 3.3 0.1-1.2 N 2 (vol%) Remaining Remaining 41.6 – 61.6 Remaining In the Table 2.6 typical syngas compositions are given relatively to the same type of reactors using air as oxidant. Table 2.6 – Typical syngas compositions by reactor type (Bridgwater, 1995). Gasifier Gas composition (vol. %, dry) HHV H (MJ/m 3 2 CO CO 2 CH 4 N 2 ) Bubbling fluidized bed 9 14 20 7 50 5.4 Updraft 11 24 9 3 53 5.5 Downdraft 17 21 13 1 48 5.7 Comparing both Tables 2.5 and 2.6 is possible to see some discrepancies especially related to CO content. This situation emphasizes the influence of the gasification conditions in the final composition of the produced gas. 2.3.3 Influence of operational conditions 2.3.3.1 Temperature Several authors have reported the increase of gas yield and the decrease in gas heat value with temperature, even when different feedstocks were employed and installation 36
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 and 30: Bibliographic revision Biomass Dryi
Page 31 and 32: Bibliographic revision Circulating
Page 33 and 34: Bibliographic revision or eliminate
Page 35 and 36: Bibliographic revision established
Page 37: Bibliographic revision Hydrogen Hyd
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
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Chapter 4 CHAPTER 4 EXPERIMENTAL AN
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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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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
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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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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
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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
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tel-00623090, version 1 - 13 Sep 20
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