Temperature-programmed desorption (TPD) profiles of H2O-gasified and O2-chemisorbed coal chars were investigated with five coals of different ranks. Coals were devolatilized in N2 and then gasified in H2O at 1100 K. Initially, TPD of the partially gasified char was determined to 1100 K in vacuo. Later the TPD experiment was repeated after the O2-chemisorption at 420 K on the above heat-treated sample. The sharp peaks in TPD patterns, corresponding to H2O, CO2, and CO evolution, all resulted from the presence of mineral matter, since no sharp peak was observed in the TPD patterns of the demineralized coal chars. The gas evolution pattern from the demineralized char was almost independent of coal type, and all of the demineralized coal chars exhibited almost the same gasification reactivities. The relationship between the gasification reactivity and the total amount of CO2and CO evolution during TPD of gasified chars and O2-chemisorbed chars is discussed.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology