Kinetic study of forest fuels by TGA: Model-free kinetic approach for the prediction of phenomena

Abstract

a b s t r a c tThe kinetics of thermal decomposition of a forest fuel was studied by thermogravimetry. Experiments were monitored under air and non-isothermal conditions from 400 to 900 K. We used a classical modelfree method, the Kissinger-Akahira-Sunose (KAS) method to calculate the activation energy vs. the conversion degree of the reaction on the whole temperature domain. Analyses were performed at 10, 20 and 30 K/min. As expected, the complex structure of lignocellulosic fuels involved several steps with different energies in the degradation processes. The algorithm developed here, allows the calculation and the simulation of the solid temperature at different conversion degree for various heating rates. The good correlation between experiments and simulations validated the proposed algorithm. Then, kinetics parameters were used to perform simulations up to heating rates outside the functioning range of the thermal analyser.

Avaliação da degradação não-isotérmica de madeira através de termogravimetria-TGA

“…Quando a degradação térmica é realizada em atmosfera oxidante há uma redução da energia de ativação nas frações mais altas (acima de 0,5) de reação, devido ao fato de que o oxigênio acelera esse tipo de reação de degradação térmica. Durante o processo degradativo em atmosfera oxidante ocorrem distúrbios causados pela competição entre a eliminação dos gases de queima e sua oxidação instantânea, que podem ocasionar em mudanças no processo difusional [36] . A determinação do mecanismo de degradação térmica pode ser realizada através do método proposto por Criado et al [14][15][16] que utiliza a função Z(a) (Equação 9).…”

Kinetic investigation on the smouldering combustion of boreal peat

“…(α) was used to perform simulations up to heating rates outside the functioning range of the thermal analyser. An algorithm previously developed for plants degradation was applied [33]. This method allows the calculation and the simulation of the solid temperature at different conversion degrees for various heating rates.…”

The Study of Thermal Destruction Kinetics of Coal and Solid Biomass Mixtures

“…Ìåòîäèêà îáðîáêè òà óçàãàëüíåííÿ äàíèõ. Ñó÷àñí³ òåðìîãðàâ³ìåò-ðè÷í³ (TGA) òà äåðèâàòîãðàìåòðè÷í³ ìåòîäè àíàë³çó ³ç çàñòîñóâàííÿì ³íôðà÷åðâîíî¿ ñïåêòðîñêîﳿ, äèôåðåíö³àëüíî¿ êàëîðèìåò𳿠øèðîêî çàñòîñîâóþòüñÿ ïðàêòè÷íî â óñ³õ ô³çèêî-òåõí³÷íèõ ãàëóçÿõ íàóêè [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Çà äîïîìîãîþ öèõ ìåòîä³â àíàë³çóâàëèñÿ ðå÷îâèíè â³ä õàð÷îâèõ ïðîäóêò³â, ïîë³ìåð³â òà òâåðäèõ ïîáóòîâèõ â³äõîä³â, á³îïàëèâ ³ äî âèêîïíèõ ïàëèâ.…”

“…Äåòàëüíèé àíàë³ç ìåòîä³â çàñòîñóâàííÿ ð³âíÿííÿ (2) äëÿ îáðîáêè åêñïåðèìåíòàëüíèõ äàíèõ ÒGA àíàë³çó òà àíàë³ç ìîäåëåé ðåàêö³é íàâåäåíî ó [1,3,4,9,10]. Ïðè íàãð³âàíí³ çðàçêà ³ç ïîñò³éíîþ øâèäê³ñòþ çà-ëåaeí³ñòü çì³íè òåìïåðàòóðè çà ÷àñîì âèãëÿäຠòàê:…”

“…Äëÿ îö³íêè òî÷íîñò³ àïðîêñèìàö³¿ ó ñåðåäîâèù³ MathCad áóëî ðîçðàõîâàíî çíà÷åííÿ ³íòåãðàëó (7) ÷èñåëüíèì ìåòîäîì òà ñï³âñòàâëåíî ³ç àïðîêñèìàö³éíèìè çíà÷åííÿìè, ðîçðàõîâàíèìè ïðè òèõ aeå çíà÷åííÿõ x. Ïðè öüîìó ïîñë³äîâíî âðàõîâóâàëèñÿ ïåðøèé, äðóãèé òà òðåò³é ÷ëåíè ðÿäó (9). Ðîçðàõîâàíî òàêîae ³ çàïðîïîíîâàíå ñï³ââ³äíîøåííÿ (10). Ðåçóëüòàòè ñï³âñòàâëåííÿ ó âèãëÿä³ çàëåaeíîñò³ ìîäóëÿ â³äíîñíî¿ ïîõèáêè â³ä ïàðàìåòðà x íàâåäåíî íà ðèñ.…”