锰酸镧钙钛矿型脱硫剂的制备及其性能评价

Preparation and Performance of Lanthanum Manganate Perovskite Desulfurizer

摘要:

以分子筛为载体，硝酸镧和硝酸锰为主要原料，通过溶胶凝胶法制备了锰酸镧钙钛矿型高温脱硫剂，通过氮气吸/脱附、X射线衍射、扫描电镜对硫化前后的织构、物相和微观结构进行表征，并基于表征结果探究脱硫机理.在固定床反应器中考察了反应温度、空速、进口硫化氢浓度、载体对脱硫性能的影响.结果表明，在500~700 ℃温度范围内，锰酸镧均具有较高的脱硫精度及穿透硫容，最佳反应温度为600 ℃；空速及进口硫化氢浓度越大，脱硫剂越容易穿透，穿透硫容越低；与三氧化二铝及纳米二氧化硅载体相比，分子筛负载锰酸镧钙钛矿型脱硫剂穿透硫容更大，脱硫精度更高.

关键词:锰酸镧; 钙钛矿; 分子筛; 脱硫; 稀土

Abstract:

Perovskite lanthanum manganate hightemperature desulfurizer was prepared using lanthanum nitrate, manganese nitrate, and zeolite as the support via citric acid method. The fabrication, phase, and microstructure of asprepared adsorbents were characterized by the nitrogen adsorption/desorption, Xray diffraction, and scanning electron microscope and energy dispersive Xray spectrum techniques, respectively. The desulphurization mechanism was investigated based on the characterization results. The effects of reaction temperature, space velocity, inlet hydrogen sulfide content, and the support on desulphurization performance were studied. The results show that the desulfurizer has a high breakthrough sulfur capacity and exhibits a high degree of purification in the temperature range of 500 to 700 ℃, and the optimal reaction temperature is 600 ℃. As the space velocity and inlet hydrogen sulfide content increase, the breakthrough sulfur capacity and breakthrough time decrease. Compared to aluminium oxide and nanosilica, zeolite supported perovskite lanthanum manganate desulfurizer has a larger breakthrough sulfur capacity and a higher desulfurization precision.

Key words:lanthanum manganate; perovskite; zeolite; desulphurization; rare earth