Influence of iron-containing petrochemical sludge ash on the pyrolysis of pine wood: Thermal behaviors, thermodynamic analysis, and kinetic parameters

Abstract

The pyrolysis characteristics and kinetics of pine wood (PW) with the presence of iron-containing petrochemical sludge ash (PSA) were studied using thermogravimetric analysis at non-isothermal conditions. The thermal conversion of PW with the presence of PSA could be characterized via a three-stage reaction, including the moisture release, pyrolysis reactions and gas–solid reaction, and solid–solid reaction between char and iron oxides. The pyrolysis characteristic parameters analysis showed that the presence of PSA indeed promoted the conversion of PW. Thermodynamic analysis revealed that the Fe2O3 in PSA was characterized by a gradual loss of oxygen during co-pyrolysis. The kinetic parameters were calculated by the Starink method combined with master-plots method. The presence of PSA would decrease the activation energy, and the minimum average value was 167.00 kJ/mol at 15% PSA addition. The most suitable kinetic models for the pyrolysis of PW and its mixtures with PSA were D3 and D4, respectively.