Determination of kinetic parameters for biomass combustion

1 De e mina ion o kine ic pa ame e s o biomass combus ion 1 Ál a ez Aa, Piza o Ca,*, Ga cía Rb, Bueno J.L.a, G. La ín Aa 2 a Depa men o Chemical and En i onmen al Enginee ing. Facul y o Chemis y 3 Uni e si y o O iedo, Julián Cla e ía 8, 33006, O iedo, As u ias, Spain. 4 b Ins i u o Nacional del Ca bón, INCAR-CSIC, c/ F ancisco Pin ado Fe 26, 5 33011. O iedo, Spain 6 7 ABSTRACT 8 The aim o his wo k is o p o ide a wide da abase o kine ic da a o he mos 9 common biomass by he mog a ime ic analysis (TGA) and di e en ial 10 he mog a ime y (DTG). Due o he cha ac e is ic pa ame e s o DTG cu es, a 11 wo-s age eac ion model is p oposed and he kine ic pa ame e s ob ained om 12 model-based me hods wi h ene gy ac i a ion alues o i s and second s ages 13 in he ange 1.75·104 – 1.55·105 J/mol and 1.62·104 – 2.37·105 J/mol, 14 espec i ely. Howe e , i has been ound ha Flynn-Wall-Ozawa and Kissinge - 15 Akahi a-Sunose model- ee me hods a e no sui able o de e mine he kine ic 16 pa ame e s o biomass combus ion since he assump ions o hese wo 17 me hods we e no accomplished in he ull ange o he combus ion p ocess. 18 19 Keywo ds 20 Biomass, combus ion, kine ic pa ame e s, Coa s-Red e n me hod, 21 he mog a ime ic analysis 22 23 1. INTRODUCTION 24 2 The impo ance o was e biomass as an ene gy sou ce is likely o inc ease 25 du ing he coming yea s as a esul o Eu opean ene gy policy a ge s 26 (Eu opean En i onmen Agency (EEA), 2010). The o al amoun o po en ial 27 biomass in Spain is abou 88,677,193 /yea (da a om Spanish Renewable 28 Ene gies Plan 2011-2020 e e encing in (Ál a ez e al., 2015)), belonging o he 29 ag icul u al and ha es ing esidues he la ges quan i y (up o 37.8% o he o al 30 po en ial biomass). 31 The e a e s ill some p oblems in cu en biomass combus ion u naces, such 32 as low he mal e iciency, ins abili y o hea load, and slagging (Szemmel eisz 33 e al., 2009; Yang e al., 2004). Compu a ional Fluid Dynamics (CFD) could be 34 use ul in sol ing hese p oblems (Dixon e al., 2005; Ma e al., 2007), bu i is 35 absolu ely essen ial ha ing a deep knowledge o he composi ion (p oxima e, 36 ul ima e and s uc u al analysis) and he mal beha iou as well as he kine ics o 37 he combus ion p ocess o biomass. 38 The aim o his a icle is o de e mine he combus ion kine ics pa ame e s o 39 he mos commonly used ypes o biomass in Spain using a he mog a ime ic 40 analyse (TGA), since his echnique is widely used in he analysis o weigh 41 loss cha ac e is ics o biomass uels (Ga cia-Ma a e e al., 2015; Kok and 42 Özgü , 2013; Maia and de Mo ais, 2016) 43 44 2. MATERIALS AND METHODS 45 2.1 Ma e ials 46 Twen y eigh di e en biomass samples we e es ed o ob ain hei ac i a ion 47 ene gy, Ea, and p e-exponen ial A henius ac o , ko, alues o combus ion. 48 3 These samples we e selec ed ying o ack a wide a ie y o di e en biomass 49 o igins such as comme cial uels, indus ial and o es was es, ene gy c ops and 50 ce eals. Thei p oxima e and ul ima e analysis da a and o he p ope ies a e 51 a ailable in a da abase p e iously published by his esea ch g oup (Ga cía e 52 al., 2014a, 2014b) . These samples we e p e- ea ed o assu e homogenei y 53 and ep oducibili y o he ca ied-ou es s and o ha aim hey we e ai -d ied o 54 a day a oom empe a u e, g inded and sie ed o 250-500 µm. 55 56 2.2. TG me hod 57 10 mg o he sample we e subjec ed o he mal decomposi ion a 4 di e en 58 low hea ing a es (5, 10, 15 and 20 K/min) in a Pe kin-Elme STA 6000, using 59 40 ml/min o bo h pu ge (N2) and ca ie (ai ) gas. 60 Pa icle diame e and, consequen ly, hea ing a es mus be low, pa icle size 61 should be smalle han 500μm (Ga cia-Ma a e e al., 2015; Pa hasa a hy e 62 al., 2013; Shen e al., 2009), while oxidizing gas lux high in o de o gua an ee 63 chemical-kine ic eac ion con ol, a oiding as possible empe a u e and 64 concen a ion g adien s (Pa hasa a hy e al., 2013). 65 66 2.3. Kine ic models 67 In he case o combus ion some au ho s conside jus one global eac ion 68 di ided in h ee di e en s ages (d ying, py olysis and cha combus ion) (Fang 69 e al., 2013; Ganga a i e al., 2005), o he s conside wo pa allel eac ions wi h 70 h ee eac ion s ages (Wang e al., 2014). Finally (Gil e al., 2010) conside s a 71 wo s age eac ion, wi h a i s s ep be ween 200-365 ºC (oxida i e deg ada ion) 72 4 ollowed by combus ion o cha be ween 365-500 ºC. A simila model is 73 p oposed by (Shen e al., 2009) and (Fang e al., 2006), who apply hose 74 me hods o a wo eac ion oxida ion- educ ion py olysis. 75 The e a e wo main ma hema ical app oaches o ob ain he desc ip o s o 76 combus ion kine ics o biomass samples: (a) model- ee me hods (iso- 77 con e sional me hods) and (b) model-based me hods. Bo h app oaches depa 78 om a gene al con e sion- ime ela ionship: 79 dα d =k(T)∙ (α) (1) Whe e (α) is he mechanis ic em and k(T) he he mal dependence e m 80 ha can be de ined by A henius law: 81 k(T)=k0∙e−EaRT ⁄ (2) Con e sion a e can be de ined as a ela ion be ween ini ial (m0), inal 82 (m∞)and ins an aneous (m ) sample mass. These da a can be ob ained om 83 each sample TG p o ile. 84 α= m0−m𝑡 m0−m∞ (3) The kine ic e m (α) depends on he condi ions and he s age o he eac ion 85 o s udy, bu i can be usually exp essed as (1-α) (Bahng e al., 2009; Fang e 86 al., 2006; Shen e al., 2009), i i s eac ion o de is conside ed. I o he eac ion 87 model is equi ed i should be subs i u ed by one o he exp essions shown a 88 Table 1. Combining bo h exp essions, he expe imen al a e o eac ion may be 89 o mula e as: 90 dα d =k0∙e−EaRT ⁄∙ (α) (4) 5 I he hea ing a e β=dT/d , is included in he p e ious di e en ial equa ion, 91 a new exp ession is ob ained ollowing a simple ma hema ical p ocedu e which 92 can be seen in p e ious a icles such as (Gil e al., 2010; Maia and de Mo ais, 93 2016): 94 dα dT=1 β·k0∙e−EaRT ⁄∙ (α) (5) The e o e: 95 dα (α)=k β∙dT→dα (α)=𝑘0 β∙e−EaRT ⁄dT (6) Then he ollowing in ege , ha mus be nume ically sol ed, is ob ained: 96 g(α)=∫ dα (α)=k0 β∫ e−EaRT ⁄dT T T0 α 0=k0𝐸𝑎 𝛽𝑅 𝑃(𝐸𝑎 𝑅𝑇) (7) The unc ion P(Ea/RT) has no exac solu ion. Thus Eq. (7) can be sol ed by 97 nume ical me hods o app oxima ions as can be seen in (Whi e e al., 2011). 98 2.3.1. Model- ee me hods 99 The model- ee me hods allow o e alua ing he A henius pa ame e s 100 wi hou choosing he eac ion o de (Janko ić e al., 2009; Ra i e al., 2012). 101 These me hods es upon he isocon e sional p inciple, which s a es ha , a a 102 cons an ex en o con e sion, he eac ion a e is a unc ion only o he 103 empe a u e (Vyazo kin and Sbi azzuoli, 2006). 104 2.3.1.1. Flynn-Wall-Ozawa me hod 105 The solu ion o Eq. 7 using Doyle’s app oxima ion (Eq. 8) (Doyle, 1961), is 106 he Flynn-Wall-Ozawa (FWO) me hod (Eq. 9) (Flynn and Wall, 1966; Ozawa, 107 1965). 108 6 𝑙𝑛[𝑝(𝐸𝑎 𝑅𝑇)]≃−5.331−1.052𝐸𝑎 𝑅𝑇 (8) 109 ln(𝛽)=𝑙𝑛(k0𝐸𝑎 𝑅𝑔(𝛼))−5.331−1.052𝐸𝑎 𝑅𝑇 (9) Eq. 8 is alid only i 20 ≤ Ea/RT ≤ 60 (Flynn and Wall, 1966). Fo a se ies o 110 measu emen s wi h di e en hea ing a es a he ixed con e sion alue α=αi, 111 he plo o ln (β) s. T-1 is a s aigh line wi h he slope m = –1.052 Ea/R. 112 2.3.1.2. Kissinge -Akahi a-Sunose me hod 113 The Kissinge –Akahi a–Sunose me hod (KAS) is ob ained using Eq. 10, 114 which is alid o 20 ≤ Ea/RT ≤ 50 (Sbi azzuoli e al., 2009). 115 p(Ea RT)≃e−EaRT ⁄ (Ea RT)2 (10) In KAS me hod, he ela ion be ween he empe a u e and hea ing a e is 116 gi en by Eq. 11 (Kissinge , 1957). 117 ln(β T2)=ln(k0R Eag(α))−Ea RT (11) The plo o he le side o Eq. 11 s. T-1 a cons an con e sion alue is a 118 s aigh line wi h he slope m=-Ea/R. 119 2.3.2. Model-based me hods. Coa s-Red e n me hod. 120 Coa s-Red e n me hod uses he asymp o ic se ies expansion o 121 app oxima ing he exponen ial in eg al in Eq. 7 (Coa s and Red e n, 1964). 122 ln(g(α) T2)=ln(k0R βEa(1−2RT  Ea))−Ea RT (12) 7 I e m 2RT/Ea is much lowe han one i can be igno ed, being he igh 123 loga i hmic e m cons an : 124 ln(g(α) T2)=ln(k0R βEa)−Ea RT (13) Plo ing he le side o Eq. 13 s. T-1, Ea and k0 a e ob ained om he slope 125 and in e cep espec i ely. Finally, he model ha gi es he bes linea i is 126 selec ed as he chosen model. 127 Se e al eac ion model o g(α) and (α) a e lis ed a Table 1. Wi h hese 128 ma hema ical app oach he kine ic iple (decomposi ion model/ eac ion o de , 129 p e-exponen ial A henius ac o and ac i a ion ene gy) can be ob ained om 130 he mal decomposi ion da a in a he mobalance scale (Bahng e al., 2009). 131 132 3. RESULTS AND DISCUSSION 133 3.1 Pa ame e s o DTG cu es 134 The cha ac e is ic pa ame e s o DTG plo s, which a e p esen ed in Fig. 1, 135 a e shown in Table 2. As shown in Table 2, he combus ion beha iou o 136 biomass samples s udied is almos he same. The e a e wo s eps in 137 combus ion o biomass, excep o cha coal, lignin and cellulose which 138 p esen ed only one s ep. The i s s ep is ela ed wi h combus ion o cellulose 139 and hemicelluloses and he second one is ela ed wi h he lignin ac ion. All he 140 empe a u es a maximum DTG (Tpeak) o i s s age a e in he ange be ween 141 249-353 ºC, while he ange o second s age is 414-627 ºC. Tempe a u e a 142 maximum weigh loss a e o cellulose is 338 ºC, which co espond o he i s 143 s age while in he case o lignin his empe a u e is 548 ºC belonging o second 144 8 s age. Thus, he i s s ep is ela ed wi h combus ion o cellulose and 145 hemicelluloses and he second one is ela ed wi h he lignin ac ion. 146 Due o he da a in Table 2, a wo-s age eac ion kine ic scheme has been 147 p oposed in his a icle: 148 A (solid)  A’ (solid) + B1 (gas) (s age 1) A’ (solid)  B2 (gas) + D (ash) (S age 2) (14) 149 3.2 Kine ic pa ame e s 150 The samples o biomass uels we e subjec ed o ou hea ing amps a 5, 10, 151 15 and 20 K/min. Ob ained da a was adjus ed using p e iously desc ibed FWO, 152 KAS and Coa s-Red e n me hod as well as nume ically using Scien is so wa e, 153 supposing i s eac ion o de in all cases, which showed a eally good 154 ma hema ical adjus . In ha way, a ou poin s aigh line was ob ained o each 155 con e sion alue om 10 o 90%, so a alue o Ea is ob ained o each 156 con e sion (FWO and KAS me hods) while only one hea ing amp da a (15 157 K/min) we e necessa y when Coa s-Red e n o nume ical me hods we e used 158 o ob ain he kine ic iple . The ob ained kine ic da a a e shown a Table 3 and 159 Table 4 o Coa s-Red e n and nume ical solu ions espec i ely. 160 When FWO o KAS me hod we e applied, hei pa icula assump ions we e 161 only accomplished in he a ange o con e sion belonging o hemicelluloses and 162 cellulose ac ions, while a he le el o con e sion o which he combus ion o 163 lignin s a s he assump ions we e no accomplished (Fig 2). In Fig 2 he alues 164 o Ea/RT o FWO and KAS me hods a e plo ed agains empe a u e as well as 165 do ed lines o maximum and minimum Ea/RT alues o bo h me hods. I can 166 9 be seen clea ly ha he assump ions o FWO and KAS me hods we e only 167 accomplished in he i s s age wi h Ea/RT alues ( ed and g een lines) be ween 168 do ed lines while hese colou ed lines a e below minimum do ed line when he 169 second s age akes place. In comme cial lignin and cha coal samples, he 170 assump ions we e no accomplished a all. Taking in o accoun ha cha coal is 171 mainly composed o lignin, i is clea ha FWO and KAS me hods canno 172 p edic ac i a ion ene gy o biomass combus ion when lignin decomposi ion 173 akes place. 174 Rega ding Coa s-Red e n and nume ical me hod kine ic da a, he ac i a ion 175 ene gy in bo h s ages is almos he same al hough i mus be s a ed ha in mos 176 samples his alue is sligh ly highe in second s age. Howe e , he ac i a ion 177 ene gy o lignin is lowe han cellulose, his is hough o be because o he 178 syne gis ic e ec . Since bo h s ages a e o e lapped, in he Coa s-Red e n 179 me hod a 𝛾- ac o is used in o de o link bo h s ages: 180 dα dT=γ(dα dT)s age 1+(1−γ)(dα dT)s age 2 (15) 181 The 𝛾- ac o is modelled as a modi ied Gompe z unc ion (Collado e al., 182 2016): 183 𝛾=1 − 𝐴 𝑒𝑥𝑝{−exp(𝜇𝑒 𝐴(𝑇𝑐−𝑇)+1)} (16) Figu es 3a and 3b show he simula ions o he Coa s-Red e n me hod. As i 184 can be seen in Table 5, whe e he Gompe z pa ame e s a e shown, A alues 185 a e close o 1 and Tc is he u ning poin be ween bo h s ages, while µ alues 186 a e ela ed wi h he a e o change o he 𝛾- ac o . 187 16 Table 2. DTG da a o biomass samples 322 Sample Fi s s age Second s age Tpeak(ºC) Tempe a u e ange (ºC) Tpeak(ºC) Tempe a u e ange (ºC) Cellulose 338 300-360 - - Lignin - - 548 450-600 Almond shell 298 250-390 477 400-720 Apple ee lea es 311 220-350 414 410-600 Bee oo pelle s 342 210-380 541 400-640 B ique e 343 260-400 509 410-550 Cha coal - - 490 400-900 Ches nu ee chips 335 260-370 473 400-520 Cocoa bean husk 312 225-350 627 425-634 Co ee bean husk 319 220-360 502 440-520 Co ncob 289 250-340 454 400-550 Eucalyp us ee chips 340 250-370 486 420-520 Ex ac ed oli e pomace 328 230-360 550 400-725 Go se 339 250-390 560 450-570 G ape seed lou 340 255-375 546 400-775 Miscan hus 307 240-340 550 450-550 Oli e s one 340 260-360 418 400-820 Oli e ee p uning 342 250-375 469 430-570 Peppe plan 311 220-374 460 400-807 Pine and pineapple lea e pelle s 324 250-360 422 400-740 Pine ke nel shell 249 270-370 515 400-820 Pineapple lea 344 250-380 496 420-570 Rice husk 334 260-360 450 400-540 Sain oin 301 230-330 456 390-522 Sc ubland p uning 334 260-370 538 400-760 This le 345 240-400 473 420-550 Vine shoo 318 250-380 468 420-500 Whea s aw 312 260-360 543 420-650 Whea s aw pelle s 300 230-365 458 400-528 323 17 Table 3. Kine ic pa ame e s ob ained by means o Coa s-Red e n me hod. 324 Sample S age 1 S age 2 ko Ea (J/mol) R2 ko Ea (J/mol) R2 Cellulose 9.47E+17 2.12E+05 0.997 - - - Lignin - - - 6.87E+03 6.95E+04 0.98 Almond shell 2.07E+03 4.82E+04 0.994 1.00E+00 1.71E+04 0.94 Apple ee lea es 3.54E+01 2.94E+04 0.997 2.65E+00 2.06E+04 0.996 Bee oo pelle s 5.36E+00 2.16E+04 0.998 3.99E+00 2.32E+04 0.98 B ique e 4.65E+02 4.28E+04 0.997 2.24E+03 5.55E+04 0.96 Cha coal - - - 9.17E-01 2.29E+04 0.98 Ches nu ee chips 1.35E+03 4.66E+04 0.998 2.83E+03 5.38E+04 0.98 Cocoa bean husk 2.86E+01 2.90E+04 0.995 6.28E-01 1.51E+04 0.99 Co ee bean husk 1.06E+02 3.46E+04 0.998 7.10E+03 6.25E+04 0.96 Co ncob 1.65E+07 8.69E+04 0.994 3.20E+00 1.95E+04 0.93 Eucalyp us ee chips 4.60E+02 4.18E+04 0.9995 1.03E+04 6.30E+04 0.98 Ex ac ed oli e pomace 5.96E+01 3.23E+04 0.993 5.08E-01 1.46E+04 0.92 Go se 3.07E+01 3.07E+04 0.997 3.31E+02 4.71E+04 0.95 G ape seed lou 8.85E+00 2.56E+04 0.995 3.09E+02 5.70E+04 0.96 Miscan hus 2.56E+02 3.79E+04 0.996 6.76E+02 5.09E+04 0.97 Oli e s one 1.37E+03 4.63E+04 0.98 7.33E+01 4.76E+04 0.91 Oli e ee p uning 1.48E+02 3.64E+04 0.9991 2.26E+00 1.92E+04 0.92 Peppe plan 4.58E+00 2.14E+04 0.9993 7.02E+01 4.73E+04 0.95 Pine and pineapple lea e pelle s 1.05E+03 4.51E+04 0.994 1.09E-01 7.35E+03 0.97 Pine ke nel shell 2.84E+02 4.05E+04 0.996 7.91E+01 4.81E+04 0.97 Pineapple lea 1.31E+02 3.69E+04 0.997 5.33E+02 4.92E+04 0.95 Rice husk 7.31E+03 5.39E+04 0.9991 4.13E+01 3.28E+04 0.92 Sain oin 1.64E+02 3.49E+04 0.996 1.88E+02 4.09E+04 0.995 Sc ubland p uning 2.26E+01 2.90E+04 0.995 2.86E+00 2.09E+04 0.92 So ghum 2.93E+03 4.99E+04 0.998 2.01E+00 1.81E+04 0.98 This le 9.64E+01 3.46E+04 0.998 5.61E+01 3.50E+04 0.99 Vine shoo 5.12E+03 5.16E+04 0.998 8.68E+02 4.82E+04 0.96 Whea s aw 1.93E+06 7.75E+04 0.96 4.13E+00 2.34E+04 0.92 Whea s aw pelle s 1.35E+04 5.46E+04 0.995 1.51E+01 2.75E+04 0.96 325 18 Table 4. Kine ic pa ame e s ob ained by nume ical solu ion. 326 Sample S age 1 S age 2 ko Ea R2 ko Ea R2 Cellulose 3.24E+10 1.26E+05 0.997 - - - Lignin 4.49E+05 9.73E+04 0.99993 Almond shell 2.97E+02 3.83E+04 0.9997 7.11E+01 4.36E+04 0.999996 Apple ee lea es 1.29E+02 3.42E+04 0.9998 2.57E+01 3.23E+04 0.999998 Bee oo pelle s 3.26E+00 1.75E+04 0.999996 1.26E+03 6.04E+04 0.9999995 B ique e 1.98E+04 5.98E+04 0.99996 3.90E+09 1.48E+05 0.9999997 Cha coal 1.09E+00 2.10E+04 0.9996 Ches nu ee chips 1.76E+05 6.88E+04 0.9998 3.01E+08 1.24E+05 0.99995 Cocoa bean husk 2.48E+02 3.77E+04 0.9998 9.87E+00 2.91E+04 0.999997 Co ee bean husk 9.03E+02 4.35E+04 0.999996 4.70E+10 1.62E+05 0.999997 Co ncob 3.99E+07 9.06E+04 0.998 1.30E+03 5.29E+04 0.999996 Eucalyp us ee chips 2.02E+03 4.79E+04 0.99995 3.69E+11 1.72E+05 0.9999997 Ex ac ed oli e pomace 2.04E+02 3.69E+04 0.9994 4.11E+01 4.11E+04 0.99998 Go se 1.28E+03 4.72E+04 0.999995 3.64E+08 1.38E+05 0.999997 G ape seed lou 1.19E+02 3.64E+04 0.99991 5.80E+00 2.84E+04 0.99997 Miscan hus 3.11E+03 4.87E+04 0.9998 4.30E+07 1.22E+05 0.999998 Oli e s one 2.00E+02 3.63E+04 0.9995 1.80E+00 2.09E+04 0.99998 Oli e ee p uning 2.31E+03 4.85E+04 0.99995 2.15E+03 5.89E+04 0.999991 Peppe plan 2.10E+01 2.68E+04 0.999993 3.58E+11 2.37E+05 0.999999994 Pine and pineapple lea e pelle s 7.78E+04 6.46E+04 0.99995 1.20E+00 1.62E+04 0.999994 Pine ke nel shell 7.07E+03 5.51E+04 0.99997 2.03E+02 5.66E+04 0.999998 Pineapple lea 3.53E+03 5.15E+04 0.999995 3.13E+04 7.61E+04 0.9999991 Rice husk 1.57E+04 5.69E+04 0.99991 1.85E+04 6.95E+04 0.99997 Sain oin 2.00E+03 4.53E+04 0.9998 2.11E+04 6.88E+04 0.999994 Sc ubland p uning 4.09E+03 5.24E+04 0.99998 3.57E+03 6.21E+04 0.99998 So ghum 1.09E+04 5.54E+04 0.9997 1.79E+01 2.81E+04 0.999980 This le 3.65E+03 5.08E+04 0.999991 2.35E+05 8.64E+04 0.999998 Vine shoo 3.24E+04 5.97E+04 0.99992 3.31E+10 1.54E+05 0.9999992 Whea s aw 2.59E+13 1.55E+05 0.9998 1.25E+01 3.06E+04 0.99997 Whea s aw pelle s 6.25E+06 8.21E+04 0.99992 3.90E+04 1.54E+05 0.999998 327 19 Table 5. Gompe z model pa ame e s o he biomass samples analysed. 328 Sample A µ (K-1) Tc (K) Almond shell 0.999 0.016 597.9 Apple ee lea es 1.292 0.074 591.3 Bee oo pelle s 0.852 0.029 638.8 B ique e 0.957 0.031 637.8 Cha coal - - - Ches nu ee chips 1.000 0.064 633.7 Cocoa bean husk 1.000 0.145 594.5 Co ee bean husk 0.879 0.032 606.9 Co ncob 1.014 0.028 573.2 Eucalyp us ee chips 0.949 0.019 621.2 Ex ac ed oli e pomace 0.996 0.017 589.7 Go se 0.976 0.012 603.6 G ape seed lou 1.372 0.018 603.2 Miscan hus 1.000 0.017 583.0 Oli e s one 1.011 0.035 616.0 Oli e ee p uning 1.016 0.023 605.2 Peppe plan 0.677 0.050 593.6 Pine and pineapple lea e pelle s 1.251 0.029 595.8 Pine ke nel shell 1.000 0.011 595.2 Pineapple lea 0.988 0.021 613.0 Rice husk 1.002 0.029 606.9 Sain oin 1.509 0.056 586.2 Sc ubland p uning 1.031 0.019 600.4 So ghum 1.000 0.052 600.5 This le 1.944 0.016 612.1 Vine shoo 0.991 0.018 593.9 Whea s aw 1.000 0.068 588.7 Whea s aw pelle s 0.976 0.023 570.8 329 20 FIGURE CAPTIONS 330 Fig. 1. DTG cu es o he combus ion p ocess (β = 15 K/min) o biomass 331 samples analysed. (PPLP in b is he pine and pineapple lea e pelle sample). 332 Fig 2. Ma ches be ween DTG and Ea alues in FWO and KAS me hods. 333 Fig. 3a. Simula ions o CR me hod; 1. Almond shell; 2. Apple ee lea es; 3. 334 Bee oo pelle s; 4. B ique e; 5. Cha coal; 6. Ches nu ee chips; 7. Cocoa 335 bean husk; 8. Co ee bean husk; 9. Co ncob; 10. Eucalyp us ee chips; 11. 336 Ex ac ed oli e pomace; 12. Go se; 13. G ape seed lou ; 14. Miscan hus; 15. 337 Oli e s one; 16. Oli e ee p uning. 338 Fig. 3b. Simula ions o CR me hod; 17. Peppe plan ; 18. Pine and pineapple 339 lea e pelle s; 19. Pine ke nel shell; 20. Pineapple lea ; 21. Rice husk; 22. 340 Sain oin; 23. Sc ubland p uning; 24. So ghum; 25. This le; 26. Vine shoo ; 27. 341 Whea s aw; 28. Whea s aw pelle s. 342 21 343 Fig. 1. DTG cu es o he combus ion p ocess (β = 15 K/min) o biomass 344 samples analysed. (PPLP in b is he pine and pineapple lea e pelle sample) 345 22 346 Fig 2. Ma ches be ween DTG and Ea alues in FWO and KAS me hods 347 0 10 20 30 40 50 60 70 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 100 200 300 400 500 600 700 800 900 Ea/RT DTG, %weigh /ºC Tempe a u e, ºC DTG Ches nu ee chips Ea/RT (FWO) Ea/RT (KAS) Ea/RT min (FWO and KAS) Ea/RT maximum (FWO) 23 348 Fig. 3a. Simula ions o CR me hod; 1. Almond shell; 2. Apple ee lea es; 3. 349 Bee oo pelle s; 4. B ique e; 5. Cha coal; 6. Ches nu ee chips; 7. Cocoa 350 bean husk; 8. Co ee bean husk; 9. Co ncob; 10. Eucalyp us ee chips; 11. 351 Ex ac ed oli e pomace; 12. Go se; 13. G ape seed lou ; 14. Miscan hus; 15. 352 Oli e s one; 16. Oli e ee p uning. 353 24 354 Fig. 3b. Simula ions o CR me hod; 17. Peppe plan ; 18. Pine and pineapple 355 lea e pelle s; 19. Pine ke nel shell; 20. Pineapple lea ; 21. Rice husk; 22. 356 Sain oin; 23. Sc ubland p uning; 24. So ghum; 25. This le; 26. Vine shoo ; 27. 357 Whea s aw; 28. Whea s aw pelle s. 358