Limestone to Remove Hydrogen Sulfide from Hot Producer Gas

摘要

Under a cooperative agreement with the Environmental Protection Agency the Bureau of Mines tested two limestone materials for their ability to remove H sub 2 S from hot producer gas (1,000 to 1,600 exp 0 F). One limestone was an essentially pure CaCO sub 3 particulate, while the other was an Illinois dolomitic limestone. The behavior of these absorbents in a bench-scale apparatus, passing simulated producer gas upward through a fixed bed of limestone, is described and the effects of operating variables (absorbent temperature, bed depth, gas velocity, and steam concentration) are discussed. The pure limestone showed little absorption capacity for H sub 2 S until heated above its calcination temperature. The effects of operating variables (bed temperature, bed depth, gas flow, and steam concentration) in 3 psig simulated producer gas were interacting as shown by a model equation. Highest absorption capacity was favored at conditions of high bed temperature, gas flow, and bed depth and by low steam concentration. The dolomite in half-calcinated condition showed limited absorption capacity at 1,100 exp 0 F in 100 psig simulated producer gas, increasing to about 10 percent of the initial dolomite weight at 1,500 exp 0 F then decreasing sharply at 1,550 and 1,600 exp 0 F. Under comparable conditions of gas flow, steam concentration, and bed depth, but in 3 psig simulated producer gas, the limestone in fully calcined condition at 1,400 and 1,600 exp 0 F showed an H sub 2 S absorptive capacity of about 34 percent of the initial limestone weight. Had the limestone been tested in 100 psig simulated producer gas, bed temperatures above 1,550 exp 0 F would have been required to maintain it in fully calcined condition.