合成甲醇铜基催化剂失活研究进展

我国甲醇工业起步较晚，在催化剂技术上与世界水平还有一定的差距。目前铜基催化剂仍存在抗毒性差、耐热差及机械强度差等方面的问题。本文综述了铜基催化剂失活的方式和机理。希望对开发高活性催化剂以合理利用我国煤及天然气资源，提供有益的参考。     

铜基合成甲醇催化剂失活研究进展

自20世纪60年代ICI公司成功推出合成甲醇铜基催化剂以来，甲醇工业得到迅速发展。然而铜基催化剂仍存在抗毒性差、耐热及机械强度差等方面的问题。综述了铜基催化剂失活的方式、机理及催化剂失活的控制手段和催化剂的再生。望能为铜基合成甲醇催化剂的改进和开发研究提供有益的参考。     

甲醇合成铜基催化剂催化活性及失活研究

主要介绍了甲醇合成铜基催化剂及其催化机理,并从制备条件和反应条件等方面对催化剂活性的影响因素进行了探讨,最后对造成催化剂失活的因素进行了具体研究。     

甲醇合成铜基催化剂中毒失活评述

阐述了甲醇合成铜基催化剂的活性机理,常见毒物如硫、氯、油、氨、金属羰基化合物等对铜基催化剂的毒害机理。并就预防失活的措施及新型甲醇合成催化剂的开发提出了建议。     

失活铜基甲醇合成催化剂中硫化物含量的测定

介绍铜基甲醇合成催化剂在长期运行过程中吸收微量H_2S中毒后,将其钝化卸出,对其组分中硫化物含量进行测定的方法。经过大量的试验,将样品在玛瑙研钵中研磨成粒度小于0.2 mm的粉末后在1 150℃充分反应,使产生的二氧化硫被碘化钾吸收,以电解碘化钾溶液所产生的碘进行滴定,根据电解所消耗的电量计算样品中硫的含量。实践表明,此方法精密度高、准确度好,可以简便、快速地测定出失活铜基甲醇合成催化剂中硫化物的含量。     

铜基甲醇合成催化剂失活原因的探讨

采用加压微型反应器和化学分析、原子吸收光谱法、X 射线荧光分析、X 射线衍射峰宽化法和其它分析方法对工业使用前后的铜基甲醇合成催化剂M K101 进行了分析和讨论。探讨了该催化剂的失活原因。     

甲醇合成铜基催化剂的研究概述

介绍了甲醇合成催化剂的分类,对常用铜基催化剂从催化机理、助剂作用及其失活原因等方面进行了综述,讨论了各种催化剂的优缺点。     

合成甲醇铜基催化剂反应条件的研究

本文叙述了反应条件对合成甲醇铜基催化剂活性(时空收率和 CO 转化率)的影响.时空收率和 CO 转化率均随反应压力的升高而增加;在一定空速范围内,时空收率随空速增大而增加,而CO 转化率随空速的增大而降低;反应温度为250℃时,时空收率和 CO 转化率均达最高值.     

甲醇合成催化剂的失活研究进展

1923年,德国BASF公司首先成功开发出ZnO-Cr2O3系高压甲醇合成催化剂,当时主要以煤制合成气制甲醇,净化技术落后,原料气中含有一定量的硫化物和氯化物,具有较好抗毒作用的ZnO-Cr2O3系催化剂比铜基催化剂更有优势。直到1966年和1972年,英国ICI公司先后成功开发CuO-ZnO系低压和中压甲醇合成催化剂,铜基催化剂才引起广泛的重视和应用。     

甲醇合成催化剂失活问题分析与处理

介绍了Shell粉煤气化制甲醇工艺中甲醇合成系统流程及生产运行情况。对合成塔催化剂运行情况进行了总结;就催化剂失活、更换频率过快问题进行了分析;并对合成回路系统进行了一系列改造:在现有合成塔上并联1台新的合成塔,分担现有合成塔一部分负荷,以降低现有合成塔催化剂生产强度,降低床层热负荷,增强催化剂抗中毒能力,延长催化剂寿命。结果表明:改造后,降低了经济运行成本,每年直接节省334万元,且确保了装置的长周期、高负荷稳定运行。     

合成甲醇铜系催化剂的研究

研究了低压事成甲醇中Ｃｕ系催化剂共沉淀制备方法,沉淀剂对甲醇合成性能的影响。     

Deactivation of Supported Copper Catalysts for Methanol Synthesis

Binary Cu/ZnO and Cu/Al₂O₃ as well as ternary Cu/ZnO/Al₂O₃ catalysts were investigated with respect to their catalytic activity and stability in methanol synthesis. In a rapid aging test, activity measurements were carried out in combination with the determination of the specific Cu surface area. A close correlation between the loss of catalytic activity and the decrease in specific Cu surface area was found due to sintering of the Cu particles. Differences in the deactivation behavior and the area-activity relationship of each catalyst system imply that the catalysts should be grouped in different classes.     

Influence of Contaminants in Steel Mill Exhaust Gases on Cu/ZnO/Al2O3 Catalysts Applied in Methanol Synthesis

The influence of impurities in steel mill exhaust gases on ternary Cu/ZnO/Al₂O₃ catalysts was studied for conventional methanol synthesis, which is one of the central reactions within the cross-industrial approach of Carbon2Chem®. A series of hydrocarbons was identified as inert spectators for methanol synthesis. Several catalyst poisons like N-containing compounds or O₂ show reversible characteristics at low pressure. However, by increasing the partial pressure of O₂, poisoning becomes irreversible, indicating different poisoning mechanisms concerning the reversibility of deactivation.     

Incorporation of Flexibility in the Design of a Methanol Synthesis Loop in the Presence of Catalyst Deactivation

This paper presents the incorporation of process flexibility into a methanol synthesis loop operating under catalyst deactivation. A design methodology is discussed with regard to catalyst deactivation, and some limitations are identified. In the current flexibility study the size of the reactor and recycle ratio have been fixed. Attempts to maintain methanol production at the rates observed with fresh catalyst included increased pressure, increased make up gas flow rate, and the injection of carbon dioxide into the make up gas at optimized inlet temperature. In order to provide flexibility and produce a design compatible with increased production rates, the effect of interrelating equipment had to be considered. As a result of catalyst deactivation, an increased flow rate is necessary and the altered process streams entering the preheater disturb the reactor inlet temperature. These issues should be considered in the design stage and may be resolved by the flexible designs presented.     

Deactivation of Copper Metal Catalysts for Methanol Decomposition, Methanol Steam Reforming and Methanol Synthesis

Laboratory and industrial results are reviewed to elucidate the general features of the deactivation of supported copper metal catalysts in various reactions involving methanol as reactant or product. Most catalyst types are based on Cu/ZnO formulations that contain stabilisers and promoters such as alumina, alkaline earth oxides and other oxides. These additional materials have several roles, including the inhibition of sintering and absorption of catalyst poisons. All copper catalysts are susceptible to thermal sintering via a surface migration process, and this is markedly accelerated by the presence of even traces of chloride. Care must be taken, therefore, to eliminate halides from copper catalysts during manufacture, and from reactants during use. Operating temperatures must be restricted, usually to below 300°C.In methanol synthesis involving modern promoted Cu/ZnO/Al₂ O₃ catalysts neither poisoning nor coking is normally a significant source of deactivation; thermal sintering is the main cause of deactivation. In contrast, catalyst poisoning and coking have been observed in methanol decomposition and methanol steam reforming reactions.     

耐硫变换催化剂失活原因综述

自Ｃｏ－Ｍｏ系耐硫变换催化剂问世以来,人们对其制备工艺、反应机理、动力学等进行了常任主细致的研究。随充变换催化剂的广泛应用,催化剂失活的原因引起了人们的普遍关注。对国内外Ｃｏ－Ｍｏ纱耐硫变换催化剂失活的原因进行了综述。     

A Comparative Study of Palladium and Copper Catalysts in Methanol Synthesis

Catalytic activity of copper supported on cerium oxide (Cu/CeO₂) in methanol synthesis from carbon monoxide and hydrogen at 473 K is similar to that of ceria-supported palladium (Pd/CeO₂). Both catalysts contain 0.3 mmol g^-1 of the active metals and the activities on a mole basis of the active metals are significantly higher than that of a commercial copper catalyst. Analyses bt EXAFS suggest that the particle size of copper in Cu/CeO₂ is similar to that of palladium in Pd/CeO₂. The activity of copper supported on silica is very low even at 523 K although the particle size of copper is close to that in Cu/CeO₂. Hence, cerium oxide promotes the activity of copper as can be seen in Pd/CeO₂.