Quality enhancement of fuel briquette from cornhusk and cassava peel blends for co‐firing in coal thermal plant

Abstract

Summary This study was carried out to evaluate the physico‐mechanical and combustion indices of briquettes made from blends of cornhusk (CH) and cassava peel (CP). The CH and CP was torrefied at 200°C to 300°C and were mixed in the ratio 90/10 to 10/90 for briquette production using D‐optimal crossed design. The fuel application for co‐firing in coal engines was evaluated with fuel ratio, combustibility index and volatile ignitability. The findings revealed that the density, durability index and compressive strength of briquettes blend at 10/90 (CH/CP) torrefied at 300°C and water preconditioned, were respectively improved by 18.19, 2.98, and 32.25% compared with those for raw briquettes at 10/90 blend ratio. Furthermore, the fixed carbon and calorific value increased with the increase in the torrefaction temperature and time. The produced briquettes at the mixing ratios of 10/90 and 30/70 (CH/CP) torrefied at 300°C for at least 1 hour is sufficient for co‐firing in coal engines. The CH and CP wastes with low calorific value which are hitherto discarded could be used to produce briquettes with appropriate qualities attributes of alternative fuel source for heating applications.

Empirical Studies on Biomass Briquette Production: A Literature Review

“…[27] were used. Corn husks, cobs and straw were mixed with other biomass, such as cassava husk [28] and oil palm husk [29]. In addition, some works also incorporated plastic waste associated with other materials in the composition of their briquettes, such as sawdust, date palm trunk and even sub-bituminous coal (non-renewable coal) [30,31].…”

“…The thermal pre-treatments of carbonization and torrefaction are employed in order to increase the energy characteristics of the fuel since the process results in increasing the amount of fixed carbon of biomass [38]. The torrefaction also presents increments in the physical quality of the briquettes, regarding their durability, density and compression strength [28]. Despite the advantages, such procedures require an extra expense of energy, since they require heating at temperatures that can range from 180 to 500 • C [26,31].…”

Synergetic Effects of Feedstock Mixture and Torrefaction on Some Briquette Characteristics of Cornhusk and Sawdust Wastes

“…The O/C and H/C atomic ratios in raw biomass blend of CH/SD briquette reduced with the increase in the torrefaction temperature. Since the heating value of the torrefied briquette blends approached that of low rank coal [3,27], reduced O/C and H/C ratios through torrefaction is an indication of maximized energy [49]. The carbon content, hydrogen content and calorific value obtained for torrefied CH/SD briquette compared well with fossil coal [50].…”

“…The torrefied samples were cooled, milled and sieved into less than 1.18 mm particle sizes to enhance the binding ability of the samples [26]. The torrefied CH and SD samples having the MC of 2.50 and 2.28% respectively were thereafter preconditioned by the spraying of 10% deionized water on mass basis and kept under 4 °C storage condition for 2 days for moisture distribution in line with Bai et al [5] and Waheed and Akogun [27]. The processed feedstock was analysed for further experiments.…”

“…Generally, all torrefied briquettes particularly at temperature of 300 °C boiled water faster than raw briquette blends. This could be due to the increase in FC and CV on biomass from the process of torrefaction [2,27,[45][46]. Moreover, the rate of heat energy expended per time is higher with SD briquettes than in CH and SD briquettes.…”