低熱量ガス化ガスの高温脱硫サイクルにおける酸素による硫化鉄の再生

概要

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Using the sulfated iron FeSα formed by sulfurization of Fe2O3 with H2S, reactivity of FeSα with O2 was investigated experimentally in a thermogravimetric analyzer (TGA) in order to demonstrate the practical feasibility of desulfurization using the Fe2O3-Fe-FeSα reaction cycle. A summary of the results obtained under the conditions employed : 1) FeSα is almost perfectly converted into original Fe2O3 above 600°C independently of oxygen concentrations and particle sizes. Below 600°C, however, the conversion to Fe2O3 is imperfect owing to the difference of reaction scheme. Furthermore, assuming the apparent single-stage reaction of first order with respect to O2 concentration, the rate expression is examined on the basis of a grain model. The value of activation energy thus obtained is 25.6 kJ/mol. 2) Fe2O3 after being regenerated several times reacts with H2S in low?calorie syngas with almost the same reactivity as that of fresh Fe2O3. 3) In the regeneration reaction, the intrapellet diffusion effect becomes increasingly significant as pellet size increases beyond 2 mm. The theoretical overall sulfurization rate showed fairly good coincidence with the measured rate when the intrapellet diffusivity of O2 was assumed to be 2.25th-order with respect to the macro-porosity in the product layer.
社団法人化学工学会の論文