Combustion of pellets produced from the powders of coconut and cashew nut shells: Chemical, thermal and emission analyses

Abstract

Most of the energy consumed worldwide comes from non-renewable sources, such as oil derivatives, making it necessary to search for renewable, clean energy sources, with emphasis on biomass from agricultural and industrial waste. Coconut shell pellets (CSPs) and cashew nut shell pellets (CNSPs) were manufactured and subsequently subjected to chemical, thermal and exhaust gas analyses of their combustion. Mean temperature results in the combustion area were 366.44 ± 84.79°C (CSPs) and 295.00 ± 89.47°C (CNSPs). The exhaust gas combustion values were 19.43 ± 0.57% (CSPs) and 18.75 ± 0.77% (CNSPs) of O2, 2348 ± 1241 ppm (CSPs) and 2901 ± 499 ppm (CNSPs) of CO, 14.92 ± 5.06 ppm (CSPs) and 39.83 ± 10.91 ppm (CNSPs) of NOx, and 441.25 ± 130.41 ppm (CSPs) and 2841.50 ± 765.26 ppm (CNSPs) of CH4. In conclusion, the combustion process of CSPs proved to be less polluting and more energy efficient when compared with CNSPs. The analyses of the exhaust gases from the combustion of these biomasses can serve as a basis for the creation of safety parameters and public policies to regulate the use of biomass for energy purposes.

Combustion of Sugarcane Bagasse Pellets Produced with/without Glycerol: Chemical, Thermal and Emission Analyses

“…Moisture content (%U) exerts direct influence on the calorific capacity of biomass and, consequently, of the resulting pellets. Our values are lower when compared to values found in previous the literature, such as those for eucalyptus sawdust pellets (15%) (Protásio et al, 2015), and green coconut shell pellets (16-17%) (Santos et al, 2022).…”

“…Volatile matter amount (%V) represents the fuel behavior during thermal decomposition. All values found for SBP30G and SBP100 are, respectively, similar to those from previous works: 83.45% to 84.98% for wood pellets (Garcia et al, 2016) and 88.09±0.85% for chestnut shell pellets (Santos et al, 2022). Based on these values, we observed that SBP30G must present a lower ignition temperature, since higher levels of volatile materials and fast emissions are factors that contribute decisively to accelerate fuel ignition at a lower temperature (Moon et al, 2013).…”

Combustion of pellets produced from corn straw and cashew nut shell in residential and industrial scenarios: Chemical, thermal and emission analyses

“…Differently from our previous study (Santos et al, 2021), different biomass (corn straw and residual glycerol) and combustion scenarios (residential and industrial) were used. Our assessments were based on two different scenarios: (i) the use of corn processing residues (corn straw) to produce pellets (with and without glycerol) for energy supply in residential use and (ii) the use of cashew nut processing residues (cashew nut shells) to produce pellets (with and without glycerol) for energy supply in industrial use.…”

“…There are previous studies that analyse, both physically and chemically, pellets of various origins (lignocellulosic, grassy, woody and agro-industrial) and from different biomasses, such as rice husk (Pereira, 2014), elephant grass (de Magalhões et al, 2016), corn straw (Carvalho et al, 2021) and cashew nut shell or coconut husk (Santos et al, 2021).…”

Coir from coconut processing waste as a raw material for applications beyond traditional uses

“…Few studies have been published on the production of biofuel pellets (Forero-Nunez et al 2012, Stelte et al 2019, Dos Santos et al 2021 and briquettes (Saha et al 2016;Brunerová et al 2017) from coconut fibers. Most studies used either shredded shells or coir pith as a raw material and only one study looked specifically into the pelletization of coir fibers (Stelte et al 2019).…”