An experimental investigation of the mass-transfer mechanisms in sulfur dioxide absorption in lime solutions
The experiments were performed at gas temperatures from 24 to 114C using a wetted-wall column apparatus with SO{sub 2} concentrations ranging from 1800 to 7350 ppM, calcium concentrations of 2.82 {times} 10{sup {minus}6} to 1. 25 {times} 10{sup {minus}5} gmol/cm{sup 3}, and column heights of 14 to 29 cm. Inlet SO{sub 2} content had a significant effect on rate of SO{sub 2} absorption, with the average absorption flux increasing with increasing SO{sub 2} gas concentration. Increasing gas temperature did not significantly affect the rate of SO{sub 2} absorption. Presence of lime in solution enhanced the average SO{sub 2} absorption flux and appeared to maintain the SO{sub 2} absorption capacity of the liquid, thereby negating the effect of decreasing SO{sub 2} solubility in water with increasing temperature. Slight increases in both the system`s gas-phase resistances and enhancement factors were observed with increasing gas temperature. Under the conditions studied, the mass-transfer resistance in the SO{sub 2}-lime solution system was predominantly liquid-phase controlled, with observed gas-phase resistances ranging up to 42% of total. Comparison to literature shows that the system mass-transfer mechanism can be dominated by either the gas-phase resistance or the liquid-phase resistance, depending upon the gas-liquid contact times. Thus, results support the need to incorporate both gas- and liquid-phase mass-transfer resistances when modeling the absorption of SO{sub 2} in lime solutions and lime slurries, such as that occurring in the constant rate drying stage of the spray drying flue gas desulfurization process.
- Research Organization:
- Carnegie-Mellon Univ., Pittsburgh, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-76OR00033
- OSTI ID:
- 10115167
- Report Number(s):
- DOE/OR/00033-T518; ON: DE93005284
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: Apr 1991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
SULFUR DIOXIDE
ADSORPTION
MASS TRANSFER
AQUEOUS SOLUTIONS
CALCIUM OXIDES
CALCIUM HYDROXIDES
LIME-LIMESTONE WET SCRUBBING PROCESSES
FLUE GAS
DESULFURIZATION
SPRAY DRYING
EXPERIMENTAL DATA
540120
200202
CHEMICALS MONITORING AND TRANSPORT
NOXIOUS GAS AND PARTICULATE EMISSIONS