Behavior of organic sulfur model compounds in pyrolysis under coal-like environment

Abstract

To simulate coal-like environment, five organic sulfur compounds, representing some of the organic sulfur structures in coal, were impregnated on a charcoal and subjected to pyrolysis in N 2. The pyrolysis was carried out in a temperature-programmed reactor at a heating rate of 5 °C min −1 up to 800 °C. The gases released (including H 2S, COS, SO 2, CS 2 and the main hydrocarbons) from the pyrolysis were analyzed by an on-line mass spectrometer (MS). It is found that the behavior of sulfur-containing compounds evolved into the gas phase depends on the structure of the compounds as well as on the functional groups on the charcoal. Sulfur radical is likely to be the main intermediate sulfur form which has strong interactions with the charcoal to form H 2S, COS, SO 2 and CS 2, and stable non-volatile sulfur compounds which crack at higher temperatures to form also H 2S, COS, SO 2 and CS 2. The carbon in COS and CS 2 are likely to come from the charcoal, and the oxygen in COS, SO 2 have close relation with the evolution of CO and CO 2, respectively. Dibenzothiophene is stable under the conditions employed.