活性炭负载钌基氨合成催化剂浸渍机理及条件研究

Study on impregnation mechanism and condition of Ru/AC ammonia synthesis catalyst

以活性炭为载体，RuCl3为钌活性前驱体，采用浸渍法制备了活性炭负载钌基氨合成催化剂，考察了浸渍条件对催化剂氨合成催化活性的影响．研究表明，在催化剂浸渍过程中，由开始的表面吸附控制逐渐向炭载体孔道内的扩散控制转变．Ru胶粒在活性炭孔道内的扩散是主要速控步骤，要获得优良的浸渍效果，适当的溶剂为H2O，同时还应控制钌浸渍水溶液的pH值在0．4～1．04左右．浸渍时间为18h，增加浸渍次数和添加竞争吸附剂的作用不明显．

The ruthenium catalyst supported on active carbon （Ru/AC） was prepared by impregnation technology. Ammonia synthesis over the catalyst was performed under the condition of 10 MPa, 400～425 ℃, and space velocity of 10 000 h 1 with synthesis gas of V（N2） ： V（H2 ）= 1： 3. The effects of various factors on the activity and Ru dispersion were studied through the analyses of the preparation technology and property of Ru catalyst. It was found that during the soak adsorption, rate-determining step was Ru colloid particles diffusion. In order to attain good catalyst, the suitable pH range of the RuCla aqueous was 0. 4 ～ 1. 04, and the impregnation time of 18 h were needed. During the impregnation, there was little impregnation effect by increasing impregnation step-program or by adding competitive adsorbate.