锰系可再生高温脱硫剂的制备及其性能测试

煤气的高温脱硫净化是 IGCC 和 DRI 生产的瓶颈,直接影响整个过程的热效率。在50℃、pH值约为9的条件下采用硝酸锰、硝酸铝混合溶液与氨水进行共沉淀,制备了锰含量不同的脱硫剂,在固定床反应器中考察了脱硫剂的硫化及再生性能,并利用XRD、SEM、BET等手段表征了脱硫剂在硫化/再生过程中的物相和结构变化。共沉淀法制备的脱硫剂Mn/Al分散性好,在850℃高温下进行脱硫反应可以定量快速进行。脱硫硫容与脱硫剂锰含量呈正比,Mn-S/Mn-O交换原子比在0.90~0.95之间,改变空速和进口H₂S含量并不改变脱硫硫容。采用O₂浓度为3%的稀释空气在850℃下再生,再生后的硫容稳定,说明所制备的脱硫剂可用于高温可再生脱硫。

Preparation and characterization of manganese-based regenerable sorbents for high temperature H2S removal

High temperature desulfurization of coal gas is a key step of integrated gasification combined cycle (IGCC)and direct reduced iron (DRI)production,which directly influences the global thermal efficiency.Manganese-based sorbents with different Mn-contents were prepared by coprecipitation method for the high temperature sulfur removal.Precipitation was conducted by neutralizing the mixed solution of manganese nitrate and alumina nitrate with 10% NH₃·H₂O at 50℃.And the pH value in precipitation was kept around 9.The sorbents prepared were tested in a fixed-bed reactor by sulfidation-regeneration cycles.XRD,SEM and BET were used to characterise the structural change of the sorbents during the cycles.The sorbents made by coprecipitation method have good Mn/Al dispersibility.The desulfurization reaction at 850℃ was rapid and quantitative.The sulfur capacity increased linearly with increase of manganese content in the sorbents.The S/Mn atomic ratio was within 0.90—0.95 after sulfurization.The sulfur capacity was not influenced by space velocity and H₂S content in feed gas.The sulfided sorbent was regenerated using diluted air containing 3% O₂ at 850℃.The sulfur capacity was stable after many cycles.So,the sorbents could be used as regenerable sulfur sorbents for high temperature H₂S removal.