Analysis of Odor Characteristics and Volatile Compounds During Spontaneous Combustion of Lignite

Abstract

To explore the main substance components and their release rules that lead to the odor of spontaneous combustion of coal, the adsorption concentration technology was used to collect the volatile substances generated during coal oxidation. A thermal desorption apparatus combined with gas chromatography-mass spectrometry(TD-GC-MS) and high performance liquid chromatography (HPLC) was used to detect the composition and concentration of volatile substances in the samples. By the odor substance evaluation method, the key odor compounds and the change rule of odor with coal temperature during coal spontaneous combustion were determined. The results show that aldehydes, alkanes, and benzene series were the main volatile substances released during coal spontaneous combustion. The composition and quantity of volatile gas were closely related to coal temperature. Among them, the critical temperature and dry cracking temperature were the key temperature points for the change of volatile gas release trend. The 6 aldehydes, that is, acetaldehyde, propionaldehyde, acrolein, butyraldehyde, valeraldehyde, and isovaleraldehyde, were the key odor substances in coal spontaneous combustion process. The threshold dilution factor of acetaldehyde was 2.5 times the sum of the other five key odor compounds at the same temperature, and it was the most critical odor substance during coal spontaneous combustion. The odor had different characteristics at different temperature of coal, and the modified odor substance was different in different stages during the spontaneous combustion of coal.

Keywords

• coal spontaneous combustion
• odor
• volatile
• odorant compounds
• acetaldehyde