Development of New Generation Ammonia Synthesis Catalyst Process

Development of New Generation Ammonia Synthesis Catalyst ProcessAmong several supports，active carbon (AC) was found to be most effective in ruthenium catalysts for ammoniasynthesis.Electronic promoter such as alkali nitrate is necessary to be added to Ru/AC. promoternitrate must be decomposed under hydrogen stream at high temperature to the corresponding oxide orhydroxide (CsNO - D23 - D2→CsOH, Ba(NO - D23 - D2) D22 - D2→BaO). In this study，this hydrogen treatment process(包含nitrate decomposition and partial methanation of thesupport AC) was found to be quite to activate the catalysts. the hydrogen treatment isrecommended to be carried out with low heating rate(10℃/min) of temperature increase up to 550℃。Promoter decomposition was completed up to 365℃因此the extra heat treatment at the high temperature initiated the methanation of carbon support. thelast process was found to be the关键因素of catalyst activationwhere carbon surrounding Ru particle is partially hydrogenated to give a proper situation ofThe excess heating （above 550℃）brings either Ru sintering or deformation ofcarbon产,poor activity. ru -CsOH/AC which is activated properly gives much higher ammonia activitythe基本原则to prepare the second generation ammoniasynthesis catalyst was established by this study。

Development of New Generation Ammonia Synthesis Catalyst ProcessAmong several supports, active carbon (AC) was found to be most effective in ruthenium catalysts for ammonia synthesis.Electronic promoter such as alkali nitrate is necessary to be added to Ru/AC. Promoter nitrate must be decomposed under hydrogen stream at high temperature to the corresponding oxide or hydroxide (CsNOィイD23ィエD2→ CsOH, Ba(NOィイD23ィエD2)ィイD22ィエD2→ BaO). In this study, this hydrogen treatment process (including nitrate decomposition and partial methanation of the support AC) was found to be quite important to activate the catalysts. The hydrogen treatment is recommended to be carried out with slow heating rate (10℃/min) of temperature increase up to 550℃. Promoter decomposition was completed up to 365℃, so the extra heat treatment at the high temperature initiated the methanation of carbon support. The last process was found to be the key factor of catalyst activation, where carbon surrounding Ru particle is partially hydrogenated (to give a proper situation of Ru-CsOH interaction). The excess heating (above 550℃) brings either Ru sintering or deformation of carbon support, which gives poor activity.Ru-CsOH/AC which is activated properly gives much higher ammonia activity than the commercial iron catalysts. The basic principle to prepare the second generation ammonia synthesis catalyst was established by this study.