Thermal conversion behavior and nitrogen‐containing gas products evolution during co‐pyrolysis of cow manure and coal: A thermal gravimetric analyzer/differential scanning calorimetry–mass spectrometer investigation

Abstract

AbstractThe kinetics and thermal behaviors of cow manure (CM) and Meihuajing bituminous coal (MHJ) blending from room temperature to 950°C were investigated by thermal gravimetric analyzer (TGA) coupled with differential scanning calorimetry (DSC) and mass spectrometer (MS). TG curves show that the high heating rate accelerates thermal decomposition rate, and the position of differential thermal gravity (DTG) peaks shifts to a higher temperature. Owing to the heat transfer limitation phenomenon, the residual weight of CM is only 40.38% with the heating rate of 1°C/min in comparison with other heating rate. DSC takes more time to reach a steady state than TGA. Gaseous evolution curves of HCN and NH3 were obtained during the pyrolysis of blends based on TG–MS experiments. With the increased heating rate, the emissions increased a lot due to the secondary reaction of volatiles. The Eα of 1C1M obtained using Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), Friedman, and Kissinger methods is within 124.58–317.18, 121.97–321.11, 150.28–331.64, and 209.26 kJ/mol, respectively. The kinetic parameters calculated based on four model‐free kinetic modeling methods shows good agreement. And the thermodynamic parameters were obtained and discussed under different conversion rates. This work is greatly important to understand the co‐prolysis mechanism of CM and coal and to design the pyrolysis reactors.