氨合成催化剂钝化经验总结

０前言化工企业每年进行的大检修中,催化剂的钝化升温及还原是比较关键的也是耗时较多的。而我厂由于氮气气源不足,空分装置较小,１００ｍ３／ｈ的氮气远远满足不了合成催化剂钝化的要求,每次钝化都需要较长的时间。１９９８年秋季检修,我们采用预先存贮氮气然后再用...     

氨合成催化剂的钝化

介绍氨合成催化剂钝化的原理、方法、使用效果和钝化工艺指标确定的原则,以及各工艺操作条件对钝化催化剂性能的影响     

氨合成催化剂研究进展

介绍了氨合成催化剂研究开发进展情况。重点介绍了新型助剂的开发及其加入方式,催化剂母体体系的改进,球形及钌系氨合成催化剂的研制开发情况等。     

甲醇合成催化剂的钝化总结

合成催化剂装填、升温、还原和使用后,随着其活性和选择性的下降,要进行更换,本文主要介绍了甲醇合成催剂的钝化,选择合理的工艺钝化方案和钝化的过程,并进行了总结。     

φ1200NC型氨合成塔催化剂的钝化

我厂采用的 NC型两轴一径氨合成塔于1 999年 6月投入使用 ,正常运行了两年多时间 ,2 0 0 1年 6月为配合系统的节能改造 ,决定改用NC型一轴两径内件。在拆旧内件前我们对催化剂进行了钝化。1　钝化的条件选择1 .1　钝化压力3～ 4MPa。钝化压力高 ,有利于催化剂的氧化 ,加快钝化速度 ,同时压力高 ,循环气量相对增加 ,有利于带走反应热。1 .2　钝化温度5 0～ 90℃。温度是催化剂氧化情况的重要标志 ,温度控制越高 ,氧化速率越快 ,而且氧化深度越大。钝化温度控制在 5 0～ 70℃为宜 ,最高不能超过 90℃。1 .3　钝化用气体本次钝化采用单台压…     

钌基氨合成催化剂的研究进展

钌基氨合成催化剂是一种在低温和较低压力下仍具有较高活性的负载型催化剂。综述了新型钌基氨合成催化剂的催化机理、国内外研究进展和工业应用情况,分析了催化剂中母体化合物、载体和促进剂等因素对催化剂活性的影响。钌基催化剂虽性能优良,但成本昂贵,因此探索新的活性组分、新的助剂与载体,研制出性能优良的钌基或非钌基催化剂是发展方向。     

Iron catalyst for ammonia synthesis doped with lithium oxide

Iron catalysts doped with Al₂O₃, CaO were obtained by melting iron oxide with 2.2 wt.% of Al₂O₃, 2.1 wt.% of CaO. The reduced catalyst was impregnated with lithium hydroxide water solution. Activity measurements were carried out in the laboratory installation in the temperature range 623–773 K under the pressure of 10 MPa. The activity of catalyst containing 0.79 wt.% of Li₂O and reduced at 773 K was similar to the activity of an industrial iron catalyst doped with potassium oxide. After reduction at 923 K the catalyst containing 0.48 wt.% of Li₂O was about 15% more active than the industrial catalyst. Increasing Li₂O concentration results in the decrease of the surface area of a catalyst reduced at 923 K. The most active catalysts doped with lithium oxide were more active than the industrial catalyst when their activity was calculated and scaled down to surface area units.     

我国氨合成催化剂的现状与发展前景

阐述了氨合成催化剂的种类、研究和使用概况,指出了氨合成催化剂的发展前景与开发方向。     

A110-1H/A110-1型催化剂在卧式氨合成塔上的应用

根据A110-1H/A110-1型催化剂在塔西南化肥厂卧式氨合成塔上的应用,总结了在卧式合成塔应用110-1H/A110-1型催化剂的一些体会,提出了更换同类型催化剂的具体操作方法。     

FeO基氨合成催化剂的机械性能研

对不同铁比值（Fe²⁺/Fe³⁺）催化剂母体的机械强度进行了研究，考察了各种条件下FeO基A301型催化剂与Fe₃O₄基A110-2型催化剂的机械强度。研究表明，催化剂母体机械强度随着Fe²⁺/Fe³⁺）的增大而增强；相同条件下A301的机械强度优于A110-2，真密度是造成两者强度差异的主要原因；助催化剂的存在对强化FeO基催化剂机械强度有一定的积极作用。     

Low temperature ruthenium catalyst for ammonia synthesis supported on BaCeO3 nanocrystals

The nanocrystalline barium cerate (BaCeO₃) was synthesized and examined as a support promoting ammonia synthesis catalyzed by particulate Ru. It was quite worthy noting that Ru/BaCeO₃ catalyst exhibited superior activity to the conventional ruthenium catalysts supported on γ–Al₂O₃, MgO and CeO₂ at low reaction temperature. The characterization including XRD, HRTEM, XPS and TPR results demonstrated that electronic interaction between Ce (IV) and Ru metals combined with strong metal-support interaction was responsible for such high catalytic activity at low reaction temperature.     

NC(ICI)74-1型氨合成催化剂的升温还原

介绍了NC(ICI) 74- 1型氨合成催化剂的性能及工业应用实例 ,着重介绍NC(ICI) 74- 1在泸天化合成一车间卡萨利轴径向合成塔中升温还原及运行情况     

活性炭负载钌基氨合成催化剂的制备

利用浸渍法制备了活性炭负载钌基氨合成催化剂,讨论了影响钌分散度与氨合成催化活性的若干因素. 研究发现,若活性炭载体具有较大的比表面和较好的孔结构将有利于活性组分的分散. 同时,在浸渍之前,样品需在100～200 ℃干燥6～8 h. 催化剂各组分浸渍后对载体的表面结构影响不同,实验发现,Ba的添加可能为Ru的分散提供了合适的表面,而K主要填充于载体中孔并和Ru充分接触,并为Ru提供电子.同时要控制母体钌水溶液的pH值,并选用合适的浸渍顺序,方能达到较好的效果.     

FeO基氨合成催化剂的可逆中毒研究

以CO₂为典型可逆毒物,系统研究了FeO基氨合成基催化剂A301的可逆中毒和解毒过程,考察了温度、压力和毒物浓度对催化剂可逆中毒和解毒过程的影响,并对比了FeO基A301型和Fe₃O₄基的A110型氨合成催化剂的抗毒和解毒能力。     

NC74-1型氨合成催化剂的升温还原及应用

介绍了NC74-1氨合成催化剂在山东华鲁恒升化工股份有限公司大氮肥氨合成的装填、升温还原及使用情况。     

Microstructure of the activated industrial ammonia synthesis catalyst

Industrial doubly-promoted iron catalysts and model systems of singly-promoted K- and Al-iron catalysts were characterised by their catalytic performance at 1 bar pressure. The relevance of bulk nitrogen for catalytic performance is shown. The catalysts were also activated in an in-situ reaction chamber of a He-ion scattering spectrometer (ISS) and their top atomic layer elemental composition was determined after they had reached similar performance as in the microreactor tests. The bulk microstructure of these samples was investigated by high resolution transmission electron microscopy (TEM) and microdiffraction.All evidence indicates that small highly crystalline -Fe platelets act as active phase. Their surfaces are covered to a large extent by promotor compounds which are partly present as poorly crystalline aggregates with iron oxide leaving only a small fraction of elemental iron directly exposed to the gas phase. The intimate contact between iron crystals and promoters particles prevents recrystallisation and is the key to the understanding of the structural stability of the catalyst system.