Development of High Temperature Infrared Spectrophotometer System and Its Application for Analysis of Thermal Decomposition Behavior of Coals

Abstract

Thermal decomposition behaviors of coals were measured by high temperature infrared spectrophotometer (high temperature IR) system. It is important to know the thermal decomposition process of coals in order to understand their chemical properties during coking reaction. Two coals were analyzed by this system. The coal samples were heated from 50°C up to 600°C in a N2 ambience, and IR spectra were measured in transmission mode every 10°C. The changes of IR spectra as sample heating were well obtained. Especially, high temperature region over 400°C, a peak intensity based on aliphatic C-H bond was decreased. While a peak intensity based on aromatic C-H bond was stable below 600°C. At least, two types hydroxyl groups were obtained in coal samples. One type is dehydrate below 400°C, another type is stable in high temperature region over 400°C. Additionally, dehydrate behavior of Kaolin which is mineral matter in coal was well obtained. Dehydrate temperature of Kaolin is used for good monitor of sample temperature. The high temperature IR system can measure of functional groups during high temperature region, and useful for analysis of thermal decomposition behavior of coals.