Comparison of the combustion characteristics and kinetic study of coal, municipal solid waste, and refuse‐derived fuel: Model‐fitting methods

Abstract

Energy crisis and solid waste management have remained challenging issues for authorities in Pakistan. These issues tend to rise with increasing population and economic growth of the society. Therefore, environmentally sustainable waste‐to‐energy program must be part of the waste management system since they may substitute fossil fuels with renewable energy sources by enabling energy recovery instead of landfill of solid wastes. In this work, the combustion characteristics of fossil fuel (coal) and solid wastes such as municipal solid waste (MSW) and refuse‐derived fuel (RDF) were investigated by thermogravimetric analysis (TGA) to compare their thermal decomposition behavior. Furthermore, proximate and ultimate analyses of these samples were carried out along with their heating values. The TGA profiles of samples indicate low reactivity of coal, whereas solid wastes present greater reaction rate reflecting their low ash and high volatile contents. It was found that the heating value of RDF sample was close to that of coal. The obtained thermal data were used to calculate the kinetic parameters using Arrhenius and Coats‐Redfern models with different reaction mechanisms. According to these models, the fuels could be arranged in order of activation energy as coal > RDF > MSW. The percentage difference between activation energy values found from Arrhenius and Coats‐Redfern models was in the range of 4.1%‐26.5%. However, the Coats‐Redfern model exhibited consistency in activation energy values, followed by a high value of R2. These results of the TGA could be very helpful to predict the combustion dynamics and confirm that MSW and RDF may be used as sustainable fuels, to meet the prevailing challenges of the energy crisis and solid waste management.

Characterisation and composition identification of waste-derived fuels obtained from municipal solid waste using thermogravimetry: A review

“…Despite these claims, the selection of the level (item, materials or chemical compounds) at which the waste sample can be sufficiently described as a mixture of several components including the identification of their thermal profiles makes the use of TGA for compositional analysis of waste samples quite challenging. This difficulty has led to another research direction, the description of thermal behaviour of SRF/RDF performing kinetic analysis with the use of TGA ( Azam et al, 2019 ; Bosmans et al, 2014 ; Grammelis et al, 2009 ), often combined with EGA ( Conesa and Rey, 2015 ; Singh et al, 2012 ). However, kinetics models are affected by the sample composition and experimental TGA conditions which are both variable ( Conesa and Rey, 2015 ) and therefore they might not be able to describe simultaneous reactions during the decomposition process ( Masnadi et al, 2014 ).…”

“…For example, the range of decomposition temperature of coal is 700–800°C and petroleum coke is 500–700°C, whereas for SRF/RDF this range is 200–600°C (under oxidative conditions) ( Akdağ et al, 2016 ). However, SRF/RDF has higher thermal resistance than MSW ( Azam et al, 2019 ). Azam et al (2019) investigated the thermal stability of MSW and RDF reporting that the peak decomposition temperature of MSW was lower (295°C) than that of RDF (341°C), whereas the range of decomposition temperature was wider for MSW (220–560°C) compared to RDF (236–554°C).…”

Isoconversional nonisothermal kinetic analysis of municipal solid waste, refuse‐derived fuel, and coal

“…The characteristics and thermogravimetric results of these samples used for evaluation of kinetics parameters are presented in our previous work. 27…”

“…The thermal behavior and kinetic data of MSW and RDF in comparison with coal with application of isoconversional are rare, it will help researchers and policymakers in great deal regarding planning of combustion and cocombustion of these fuels. The characteristics and thermogravimetric results of these samples used for evaluation of kinetics parameters are presented in our previous work 27 …”

“…Proximate & ultimate analysis of samples27 The combustion characteristics parameters for Coal, MSW, and RDF from TG and DTG curves…”