Pyrolysis Behavior and Kinetics of Typical Crop Straw in Henan Province at Different Heating Rates

Abstract

Straw, which is characterized by its low cost, large quantity, and rich supply of biomass energy, is often converted into energy that can be utilized in industrial production through pyrolysis technology. This paper examines the pyrolysis experiments of four kinds of straw (rice, wheat, peanut, and corn) from the Henan Province of China, conducted in an air environment with varying temperature-rise rates. Based on the experimental results, an analysis was conducted on the effect of the rate of temperature rise on the degree of straw pyrolysis and the pyrolysis characteristics of each type of straw. The activation energies of the pyrolysis reactions were calculated utilizing the Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Starink methods. It was concluded that the pyrolysis process of all four types of straw could roughly be classified into three stages: dehydration and drying stage, volatile release stage, and carbonization stage. Among the four types of straw evaluated, rice straw exhibited the most favorable combustion performance, while wheat straw demonstrated the best pyrolysis effect. Increasing the heating rate resulted in a pronounced thermal hysteresis effect during the straw’s pyrolysis, as evidenced by the TG and DTG curves shifting toward higher temperatures. The reaction speed increased as the heating rate increased, and the amount of residual carbon displayed an upward trend.