報告書番号

W01001

タイトル（和文）

亜鉛フェライト含有脱硫剤の脱硫サイクル繰り返し性能 -－硫黄吸収容量の低下要因の解明と長期性能評価法の構築－-

タイトル（英文）

Performance of Zinc Ferrite Sorbent during Multiple Desulfurization Cycles. - Diagnosis of Sulfur Capacity Decrease and Suggestion of Method for Evaluating Long Term Performance. -

概要 （図表や脚注は「報告書全文」に掲載しております）

石炭模擬ガス中での亜鉛フェライト－二酸化珪素複合粒子の硫化反応経路を解明し，加圧熱天秤による硫化反応の重量変化から，同粒子含有脱硫剤の亜鉛と鉄の吸収容量を区分測定した。20回の脱硫サイクルまでは，硫黄吸収容量の漸減傾向の主因は亜鉛の硫酸塩化である。硫黄吸収容量の低下と低濃度除去性能の関係を把握するため，，硫化反応が瞬時に完了するとした固定床での硫黄吸収モデルを前提に，脱硫サイクルと1ppm破過時間の関係を予測した。20回以降も亜鉛の硫黄吸収容量が直線的に低下する場合には40回程度で1ppm破過時間に影響が出るが，初期の４割程度で安定して維持されれば，500回（１年相当）の繰り返しでも影響は小さいと予測された。亜鉛の硫黄吸収容量の低下傾向を把握して，本脱硫剤の長期性能を評価する必要がある。

概要 （英文）

Reduction and sulfidation paths of zinc ferrite‐silica composite powder were revealed at a simulated coal gas condition. The mechanisms were reflected to analyze thermogravimetric data on sulfidation of the sorbent containing the composite powder obtained by a pressurized thermobalance. The analyses of the data divided sulfur capacity by its attribution to zinc and iron. Change in sulfur capacity attributed to zinc was measured up to 20 repetitions of desulfurization cycles of the sorbent in the pressurized simulated coal gas condition. During the cycles, main factor of decreasing sulfur capacity was the capacity decrease due to zinc sulfate formation. The effect of the zinc on the performance of sulfur removal at lower concentration was estimated through the reaction model on sulfur removal in a fixed bed reactor assuming infinite sulfidation rate. The 1 ppm breakthrough time is shorten when the zinc contribution on sulfur capacity was linearly decreased with repetition cycles. The breakthrough time, however, is insensitive to the zinc capacity over than five hundred cycles (corresponds to one year), when the capacity maintained around 40% of its initial value. Because the sulfur capacity decrease due to zinc sulfation is critical to the longer term stability of the sorbent, thus, evaluation over 40 cycles of desulfurization cycles are necessary to confirm the multicycle stability of sulfur removal performance of the sorbent.

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