Torrefaction of some Nigerian lignocellulosic resources and decomposition kinetics

Abstract

Torrefaction experiments were carried out on some Nigerian woody (Albizia pedicellaris (AP), Tectona grandis (TK), Terminalia ivorensis (TI)) and non-woody (Sorghum bicolour glume (SBG) and stalk (SBS)) biomass resources. The influence of process conditions and consequent change in the elemental configuration of the biomass samples were observed. Biomass type played a dominant role in the solid yield recording 71% for woody and 58% for non-woody samples at 270 • C, while temperature showed the greatest influence with solid yield dropping from an average of 80% (at 240 • C) to 50% (at 300 • C). Both volatile matter and fixed carbon contents experienced significant changes after torrefaction and a decline in O/C ratio from 0.6 to 0.3 was noted. Among the woody biomass, TI experienced the highest increase in higher heating value (HHV) of approximately 38% as compared to AP (32%) and TK (32%), and was subsequently selected for decomposition kinetic study. The decomposition kinetics showed that activation energy (E(˛)) for the hemicellulose degradation stage ranged between 137 and 197 kJ mol −1 for conversion (˛) between 0.1 and 0.24 implying that biomass kinetics within this decomposition region is a multi-step reaction. The GC/MS analytical technique revealed that the presence of levoglucosan was highest (7.1%) in woody biomass, while phenolic compounds made up more than one-third of the group of compounds identified.

Thermo-kinetic, spectroscopic study of brewer’s spent grains and characterisation of their pyrolysis products

“…This trend agrees with previous findings in literature [39]. The DTG thermogram for extractive-free BSG showed a shift toward higher temperature.…”

“…Levoglucosan is an intermediate product from the decomposition of cellulose. Some of the constituents of the extractives may have being responsible for the disparity because it has been reported that the presence of inorganic minerals influences the liberation of levoglucosan [39]. In addition, the number of detectable chemical compounds in the BSG was much higher than those of ext-free BSG.…”

Production and characterization of bio-oil and biochar from the pyrolysis of residual bacterial biomass from a polyhydroxyalkanoate production process

“…The average E and A values were 199 kJ mol −1 and 1.07 × 10 24 , respectively. These parameters were similar to other lignocellulosic biomass [28,36] and protein-rich sewage sludge [18].…”

Combustion characteristics and kinetics of torrefied olive pomace

“…In addition, the physicochemical properties of the solid fuels were characterized including elemental composition, ash fraction, heating values, surface function groups FTIR (Fourier transform infrared spectroscopy), surface area and pore size distribution [10e19]. The kinetics of the biomass torrefaction were also examined using isoconversional methods [20,21]. Furthermore, the gaseous products were analyzed in order to assess their possible recovery in the torrefaction plant [21e25].…”