KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

Kwon, K. C.

Tuskegee University (United States)

关键词: Sulfur Dioxide;    01 Coal, Lignite, And Peat;    Oxidation;    Kinetics;    Packed Beds;   

DOI  :  10.2172/815459
RP-ID  :  NONE
RP-ID  :  FG26-00NT40835
RP-ID  :  815459

美国|英语

来源: UNT Digital Library

【 摘 要 】

The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 60-{micro}m C-500-04 alumina catalyst particles and a PFA differential fixed-bed micro reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into elemental sulfur were carried out for the space time range of 0.01-0.047 seconds at 125-155 C to evaluate effects of reaction temperatures, moisture concentrations, reaction pressures on conversion of hydrogen sulfide into elemental sulfur. Simulated coal gas mixtures consist of 61-89 v% hydrogen, 2,300-9,200-ppmv hydrogen sulfide, 1,600-4,900 ppmv sulfur dioxide, and 2.6-13.7 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 100-110 cm{sup 3}/min at room temperature and atmospheric pressure (SCCM). The temperature of the reactor is controlled in an oven at 125-155 C. The pressure of the reactor is maintained at 28-127 psia. The following results were obtained based on experimental data generated from the differential reactor system, and their interpretations, (1) Concentration of moisture and concentrations of both H{sub 2}S and SO{sub 2} appear to affect slightly reaction rates of H{sub 2}S with SO{sub 2} over the moisture range of 2.5-13.6 v% moisture at 140 C and 120-123 psia. (2) Concentrations of both H{sub 2}S and SO{sub 2} appear to affect slightly reaction rates of H{sub 2}S with SO{sub 2} over the temperature range of 135-145 C at 5-v% moisture and 112-123 psia. However, reaction rates of H{sub 2}S with SO{sub 2} appear to decrease slightly with increased reaction temperatures over the temperature range of 135-145 C at 5-v% moisture and 112-123 psia. (3) Concentrations of both H{sub 2}S and SO{sub 2} appear to affect slightly reaction rates of H{sub 2}S with SO{sub 2} over the pressure range of 28-123 psia at 5-v% moisture and 140 C. However, reaction rates of H{sub 2}S with SO{sub 2} increase significantly with increased reaction pressures over the pressure range of 28-123 psia at 5-v% moisture and 140 C.