Pyrolysis Characteristics, Kinetics, and Its Product Characteristics of Grape Stem

Abstract

Grape stem is a kind of agricultural and forestry waste. A fundamental understanding of grape stem pyrolysis behavior and kinetics is essential for its efficient thermochemical conversion. Thermogravimetric infrared spectroscopy and pyrolysis gas chromatography-mass spectrometry, combined with two model-free integral methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were used to investigate the weight loss behavior, the distribution and content of rapid pyrolysis products, the release law of small molecule pyrolysis gases, and the pyrolysis activation energy during pyrolysis. The results showed that the main pyrolysis reaction temperature ranged from 240 °C to 690 °C. The pyrolysis reaction of grape stems at 200 °C to 700 °C was divided into three stages: 0.15 < α < 0.35, 0.35 < α < 0.65, and 0.65 < α < 0.75, which corresponded to the main pyrolysis stages of hemicellulose, cellulose, and lignin, respectively. The products of rapid pyrolysis at 290 °C were mainly composed of acids and sugars, while the products at 355 °C were mainly phenolics. This study aims to provide a theoretical reference for the pyrolysis gasification test of grape stem.