Beneficial transitions in thermogravimetric signals and activation energy levels due to briquetting of raw pigeon pea stalk

Benefits of weakening in thermogravimetric signals of hemicellulose and lignin for producing briquettes from soybean crop residue

“…Activation energies for few apoints were not computed as shown in Table 3. The E-values obtained in present studies (Table 3) were in consonance with the Evalues of lignocellulosic biomaterials as given by White et al [26], Gangil [4,5,30,31,43,44] and Tsamba et al [45]. Fig.…”

“…Gangil / Energy xxx (2015) 1e9 5 enhance in SB which was explained using the activation energy analysis later in this writing. Gangil [4,5,30] stated that in case of stresses, either due to pressure or temperature or both, on the lignocellulosic biomaterials, the lignin in biomaterial first relaxed, then melted during stresses, and finally solidified in final-product (i.e., briquettes in present discussion). This article considered that the solidification of melted lignin was the one of the probable major causes of thermal stability in SB.…”

“…These signals were ascribed to release of methane or hydrogen by them. Gangil [4,5] stated that the region of 700e750 C could be represented by release of methane (700e730 C) and release of hydrogen (near 750 C) due to charring reactions in case of pigeon pea stalk and its briquetted biofuel, respectively. Abdullah et al [41] mentioned that the charring TGsignals might be due to the secondary reactions in lignin degradation.…”

“…During the TG-studies on plastic polymers and on specific biocomponents (like xylan, cellulose and lignin in extracted or separated or refined form), normally R 2 is taken as >0.9 for isoconversional kinetics. In case of biomaterials where one kind of biopolymeric molecules make complex linkages with other kind of molecules, the R 2 was taken as >0.8 considering the complexity in internal molecular networking during thermal degradation of biomaterials [4,5,30]. Activation energies for few apoints were not computed as shown in Table 3.…”

“…There are various methods for determination of kinetics [4,5,21e40] of thermal degradation, like Friedman method, CoatseRedfern method, Kissinger, KissingereAkahiraeSunose (KAS) method, and OzawaeFlynnewall (OFW), etc. The KAS, OFW and CoatseRedfern methods are integral isoconversional methods whereas Friedman is differential method [4,5,26,27,29]. Kissinger method is basically not an isoconversional method.…”