Temperature and time effect on the concentrations of free radicals in coal: Evidence from laboratory pyrolysis experiments

✍ Scribed by Nansheng Qiu; Huili Li; Zhijun Jin; Yinkang Zhu

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 221 KB
• Volume: 69
• Category: Article
• ISSN: 0166-5162
• DOI: 10.1016/j.coal.2006.04.002

✦ Synopsis

The relationships between free radical concentration (N g ) and vitrinite reflectance (%R o ) of coal were tested through 36 laboratory anhydrous pyrolysis experiments. The experiments were carried out at isothermal reactor with pyrolysis temperatures ranging from 300 to 550 °C over 30-480 min. The effects of temperature and retention time on the N g were investigated. The concentrations of free radicals in pyrolysis coal samples increase with increasing time and temperature of experiments and reach a maximum value at about 1.75 %R o , and then decrease with further maturation. The Temperature Time Index (TTI) integral equation was applied to establish the relationship between the TTI and N g in this paper. As the free radical concentration in organic matter is strongly maturity dependent, it may prove to be a valuable geothermometer for paleogeotemperature study in sedimentary basins.