• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.395-401
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• 2004

In this study, lots of methods have been studing to utilize energy and decrease contaminated effluents. There has been great progress on IGCC (Integrated gasification combined cycle) to reduce thermal energy losses. The following results have been conducted from desulfurization experiments using waste shell to remove $H_{2}S$. Unreacted core model ior desulfuriration rate prediction of sorbent was indicated. These were linear relationship between time and conversion. So co-current diffusion resistance was conducted reaction rate controlling step. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. Maximum desulfurization capacity was observed at 0.631 mm for lime, oyster and hard-shelled mussel. The kinetics of the sorption of $H_{2}S$ by CaO is sensitive to the reaction temperature and particle size at $800^{\circ}C$, and the reaction rate of oyster was faster than the calcined limestone at $700^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.248-254
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• 1997

The sulfidation behavior of a sputter-deposited amorphous coating of 69.0%Nb-16.9Ni-11.9%Al-2.2%Si (at.%) has been investigated as a funtion of temperature.(973-1173K) in pure sulfur pressure of 0.01atm. The sulfidation kinetics of the casting obyed the parabolic rate low over the whole temperature ranges studied. The stlfidation rate increased with the temperature, as expected. The sulfide scale, the composition of which was $Al_2S_3,\;NbS_2,\;Ni_{3-x}S_2\;and\;FeCrS_4$, formed on the amorphous coating was primarily bilayered. Both the outer fastgrowing non-protective 4Al_2S_3$scale and the inner slowly-growing protective $NbS_2$,/TEX> scale and the inner slowly-growing protective $NbS_2$ scale had some Fe and Cr dissolution, which evidently came from the base substrate alloy of stainless steel type 304. Belows the coating, Kirkendall void formation was noticed. Nevertheless, a dramatic improvement of sulfidation resistance was achieved by sputter-depositing Nb-2 Ni-Al-Si layer on the stainless steel 304.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1998.04a
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• pp.144-153
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• 1998

Sorbents of calcined limestone and oyster particles having a diameter of about 0.63mm were exposed to simulate fuel gases containing 5000ppmv H2S for temperatures ranging from 600 to 800C in a TGA. The reaction between CaO and H2S proceds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. The kinetics of the sorption of H2S by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.125-133
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• 1999

Sorbents of calcined limestone and oyster particles having a diameter of about 0.63mm were exposed to simulated fuel gases containing 5000ppm $H_2S$ for temperatures ranging from 600 to 80$0^{\circ}C$ in a TGA (Thermalgravimetric analyzer). The reaction between CaO and $H_2S$ proceeds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. The kinetics of the sorption of $H_2S$ by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.

• Journal of Environmental Health Sciences
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• v.14 no.1
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• pp.11-22
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• 1988

Calcium oxide, lithium oxide and titanium oxide were investigated as additives of zinc oxide for the removal of hydrogen sulfide at high temperature. This experiment was performed in the range of 1.0-2.0 vol.% H$_2$S concentration at 623-873 K reaction temperature, using a thermogravimetric analyzer. A pore blocking model was found to fit the reaction rate and the kinetics data were sucessfully expressed by this model. The reactions between additive sorbents and hydrogen sulfide were first order with respect to hydrogen sulfide concentration in a gaseous mixture with nitrogen. Among the used sorbents, ZnO-CaO 0.5 at.% and ZnO-TiO$_2$ 2.0 at.% sorbents had the best additive effects on the sulfidation reaction between additive sorbents and hydrogen sulfide, whereas the ZnO-Li$_2$O sorbents were ineffective.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2067-2076
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• 2000

The experiments have been made to develop manganese-based sorbent(MT, MFT) for the removal of hydrogen sulfide from simulated hot coal gases. Manganese-based sorbents were tested in an ambient-pressure fixed-bed reactor to calculate H2S removal efficiency. and a three hole jet attrition tester to characterize the sorbent physical properties. According to the experimental results of attrition test. the attrition resistance of 5% bentonite containing sorbent was higher than that of 2% bentonite. The attrition resistances of both sorbents increased with induration temperature. Effects of sulfidation temperature. space velocity. and $H_2S$ concentrations on the $H_2S$ removal efficiency were investigated. Experimental results showed that $H_2S$ could be removed from 5,100ppmv to 20ppmv at $450^{\circ}C$, and to 30~65ppmv at $550{\sim}650^{\circ}C$ for both MT/MFT sorbents. As for the change of space velocity, the breakthrough time was decreased with space velocity.

• Clean Technology
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• v.7 no.3
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• pp.187-194
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• 2001

The desulfurization process which belongs to the gas refining part is the unit process that eliminates $H_2S$ and COS in the coal gas formed by the coal gasification part in the integrated gasification combined cycle(IGCC). In this study, natural manganese ores were selected as the raw material of the desulfurization sorbent due to economical efficiency. Initial rates for the reactions between $H_2S$ and desulfurization sorbent using natural manganese ores were determined in a temperature range of $400{\sim}800^{\circ}C$ using a thermobalance reactor. All reactions were first order with respect to $H_2S$ and were in accord with the Arrhenius equations. When sulfidation reaction was controlled by diffusion, the temperature dependence of the effective diffusivity was given by the Arrhenius equation. Activation energies and frequency factors were obtained from the product layer diffusion coefficient of various sorbents by plotting as Arrhenius equation form.