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In order to understand the behavior of COS in a ZnO desulfurization reactor, the reaction between ZnO and COS was studied in the presence of gases which compose a coal-derived gas. The behavior of COS in the reaction zone of a ZnO packed bed can be predicted as follows:  H2S in coal-derived gas reacts more easily with ZnO than COS; most of COS is converted to H2S by catalytic hydrolysis and then reacts with ZnO, although a part of COS may react directly with ZnO; H2 accelerates the conversion of COS to H2S; the water−gas shift reaction accelerates the reaction between ZnO and COS; and CO2 does not affect the reaction.

The reaction between zinc oxide and hydrogen sulfide was studied in the presence of coalderived gases. The reaction was inhibited by the presence of H2O. The effect of CO2 on the reaction was smaller than that of H2O. H2 accelerated the reaction at 500 °C and inhibited it at 400 °C in the presence of H2O. CO also inhibited the reaction in the presence of H2O. COS was formed from H2S and CO in the absence of H2. Elemental sulfur was formed from COS only under the H2S-N2 system. In explanation of the experimental results, a reaction scheme has been presented.

The catalytic effectiveness factors with variable rate constants and diffusivities were theoretically studied. In this work, the fundamental analysis was undertaken for an isothermal first order reaction on the assumption of linear or hyperbolic rate constant-diffusivity distributions with depth of a flat plate catalyst. The effectiveness factors were correlated as a function of generalized Thiele modulus taking account of the distribution functions, or in terms of apparent rate parameter, ratio of overall rate to rate on external surface, and respective arithmetic mean value of rate constant-diffusivity.

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