Characteristic Analysis of Torrefied Pellets: Determining Optimal Torrefaction Conditions for Agri-Byproduct

Abstract

This study considers the possibility of utilizing agri-byproducts as energy sources via pelletization and torrefaction. Pellets were placed in a capsule and torrefied in an electrical furnace. Subsequently, they were cooled for 30 min, and their mass loss was measured. To investigate the resulting changes in fuel characteristics, ultimate and proximate analyses were performed, and calorific values were measured. To estimate the water absorption of the pellets, hygroscopicity evaluations were conducted. Based on the experimental results, the energy yield, lower heating value, and exergy were calculated to determine the optimum conditions for torrefaction. The calculation was performed by utilizing the useful exergy and standards applied to biomass power plants. We determined that torrefaction for agro-pellets should be conducted under low-to-intermediate temperatures (210–250 °C) within a period of 50 min. Under these conditions, 7–55% mass reductions were observed, the higher heating value increased from 4110 to 6880 kcal kg−1, and the lower heating value changed from 3780 to 6520 kcal kg−1 owing to reduced hygroscopicity. So, Agro-byproducts can contribute to the practical application by improving the heating value through torrefaction as an alternative to wood pellets.

Influence of Torrefaction and Pelletizing of Sawdust on the Design Parameters of a Fixed Bed Gasifier

“…Results of the ultimate analysis (Table 1), show increased carbon content of the torrefied biomass, when comparing to untreated wood. This trend has been confirmed by many different studies, for many different types of feedstock [62,[79][80][81][82][83][84]. Similarly, an increase in HHV of torrefied wood was observed, which is similar to results reported different types of biomass in different studies [85][86][87][88].…”

Torrefaction and Densification of Wood Sawdust for Bioenergy Applications

“…After proximate analysis of biochar samples, the volatiles decreased from 77% for optimized treatment to 41% for the most extreme torrefied samples and conversely, fixed carbon improved from 18 to 52% in that respect (Figure 6A). A similar pattern has been observed by other researchers [2,[71][72][73][74][75][76][77] of increased carbon content after the torrefaction of several types of biomass. Although for ash content, no trend was apparent during torrefaction, the effectivity of the batch torrefaction unit for producing high-quality fuel from After proximate analysis of biochar samples, the volatiles decreased from 77% for optimized treatment to 41% for the most extreme torrefied samples and conversely, fixed carbon improved from 18 to 52% in that respect (Figure 6A).…”

“…Although for ash content, no trend was apparent during torrefaction, the effectivity of the batch torrefaction unit for producing high-quality fuel from After proximate analysis of biochar samples, the volatiles decreased from 77% for optimized treatment to 41% for the most extreme torrefied samples and conversely, fixed carbon improved from 18 to 52% in that respect (Figure 6A). A similar pattern has been observed by other researchers [2,[71][72][73][74][75][76][77] of increased carbon content after the torrefaction of several types of biomass. Although for ash content, no trend was apparent during torrefaction, the effectivity of the batch torrefaction unit for producing high-quality fuel from sawdust was verified by these data.…”

Synergetic Co-Production of Beer Colouring Agent and Solid Fuel from Brewers’ Spent Grain in the Circular Economy Perspective

“…However, thr relatively low N content (Figure 5) suggests that the content of proteins was not significant. Similar trends, in terms of the location on Van Krevelen's diagram with increased severity of torrefaction, were observed for various lignocellulosic species of biomass, such as wood [113,114], beechwood [115], miscanthus [115], Sida hermafrodita [97], Erianthus arundinaceus [96], pepper pellets [114], perilla stem pellets [114], and Kenaf [116].…”