Kinetics of pyrolysis and gasification of cotton stalk in the central parts of India

[Display omitted] •Cotton stalk is characterized and investigated for pyrolysis and CO2 gasification reactions.•Single Reaction and Distributed Activation Energy models explains the pyrolysis kinetics.•Gas evolution and tar formation are studied for cotton stalk pyrolysis at 10 K/min heating rate.•Surface area of char during CO2 gasification reaction goes through a maximum.•Modified Random Pore Model explains the kinetics of CO2 gasification of char. The paper presents a detailed study on both, pyrolysis and gasification of cotton stalk, investigated using Thermo-gravimetric Analyser (TGA) and a fixed bed reactor. The pyrolysis experiments are conducted at different heating rates over a range 5–30 K/min in an inert medium. Pyrolysis reactions are observed to be dependent on the operating condition and chemical composition confirmed by FTIR analysis. Gas evolution kinetics during pyrolysis process and tar formation are also studied in a specially designed fixed bed reactor. CO2-char gasification experiments are conducted at different temperatures over a range of 973–1123 K. The char gasification reaction is observed to be dependent on char surface area and inorganic content of biomass. The kinetic parameters for pyrolysis are estimated using model-free/model-fitting methods such as Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Coats-Redfern (CR), Single Reaction Model (SRM), and Distributed Activation Energy Model (DAEM). The kinetic parameters for CO2 gasification are estimated using Random Pore Model (RPM) and Modified RPM.