Assessment of Efficient Thermal Conversion Technologies and HHV from Compositional Characteristics of Cassava Peelings, Plantain Peelings and Corn Cobs

Abstract

The understanding of compositional characteristics permits to predict the efficient thermal conversion technologies and Higher Heating Value (HHV). Although HHV can be determined directly, many models have been proposed for HHV prediction. They are based on proximate, ultimate, and structural analysis and require much data collected. The present work assesses to predict efficient thermal conversion technologies and HHV of the most abundant agricultural biomass from Cameroon, namely cassava peelings, plantain peelings, and corn cobs, by using the existing models and exploring the calculation of HHV from the formula. The results show that investigated biomasses can be efficiently used in thermochemical conversion to produce bio-oil/syngas, in the biochemical process to produce bioethanol/biogas, and in the physical process to densify feedstock into fuel briquette. Flue gas reveals a value less than the toxic values fixed by the European standard for household waste incineration and can therefore be used as an environmentally friendly bioenergy source. Nevertheless, the levels of S and N could be taken into account in the design of a gasification plant to control the emission of NO2 and SOx-derived pollutants as their value is more than the limit fixed. Amongst the existing models, the model based on ultimate analysis gives the best correlation. The Average Absolute Error (AAE) is ranging from 2.47 to 10.71%. The calculation of HHV from combustion enthalpy and the formulae of cassava peelings, plantain peelings, and corn cob are C5H4O2, C5H8O4, and C3H4O2 respectively. The HHV derived from them is 16.13, 16.27, and 20.02 MJ/kg for cassava peelings, plantain peelings, and corn cob respectively. The AAE lies within 2.52 and 8.08%. These values are lower than those obtained from the literature models. These AAE varies between 4 and 10%. The AAE of the twenty biomasses from the literature ranges from 0.16 to 10.96%.

Comprehensive Characterization of Some Selected Biomass for Bioenergy Production

“…This diminishes its usefulness as a fuel source. Consequently, high MC leads to a decrease in HHV . It was revealed that lemongrass, sawdust, and cashew leaves had the lowest MC and hence a high HHV.…”

“…Through thermochemical conversion technologies, the HHV and FC contents are increased by carbon content . Hydrogen content also contributes to increase the HHV value while nitrogen has the opposite effect . The oxygen content is the most vital fuel property because it gives the combustion behavior of the fuel.…”

“…Consequently, high MC leads to a decrease in HHV. 80 It was revealed that lemongrass, sawdust, and cashew leaves had the lowest MC and hence a high HHV. High VM does not translate to a high HHV, as some components of VM are derived from noncombustible gases.…”

“…86 Hydrogen content also contributes to increase the HHV value while nitrogen has the opposite effect. 80 The oxygen content is the most vital fuel property because it gives the combustion behavior of the fuel. During the thermochemical conversion processes (pyrolysis), thermal reactivity is increased due to higher oxygen content.…”

“…87 Nitrogen and oxygen contents are indicative of potential gas emissions during combustion. Inna et al 80 noted that NO 2 is a hazardous respiratory toxic and when combined with sunlight contributes to ozone depletion. Biomass fuels can be classified based on nitrogen concentrations (Figure 5) as low-N fuels (<0.4%), medium-N fuels (0.4−1%), and high-N fuels (1−10%).…”