Investigating on the Iconic Gas Compositions Produced by Low-Temperature Heating Cotton

Abstract

This study aims at achieving the generation laws of the iconic gas compositions produced during the process of the cotton smoldering. A mini tube furnace was used to heat a long-staple cotton sample from Xinjiang, China, and a gas chromatography-mass spectrometer (GC/MS) was applied to analyze the produced organic and inorganic gas composition at different low temperatures ranging from 95 °C to 185 °C. Besides, a thermogravimetric experiment under air atmosphere was done in order to verify the correctness of the inferences. The pathways of product generation by heating cotton were set forth, including the depolymerization of the cotton cellulose, the sequential generation of coke, low molecular weight products, long chain carboxylic acids, levoglucosenone, and acetone at 125 °C, and the generation of hydrogen at 95 °C, carbon dioxide, carbon monoxide at 145 °C, and methane during the heating process. The results showed that the alkanes, furans, alkenes, aldehydes, hydrazines, and acids could not be regarded as the iconic gas compositions because of their little proportion, the joint detection of the methane and hydrogen could be used to predicate the smoldering, and the acetone and carbon monoxide could be used to confirm the smoldering stage. The results of the thermogravimetric experiment are consistent with theoretical analysis, indicating that analyses are reliable. This work will provide significant practice foundation for the early warning and prevention of cotton fires.