共查询到20条相似文献,搜索用时 93 毫秒
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苯酚直接羟化制备苯二酚催化剂失活过程研究 总被引:2,自引:0,他引:2
催化剂失活是一个复杂的物理和化学过程,失活原因多种多样,催化剂失活对催化过程的工艺流程、设备以及操作条件等的选择起着决定性的作用。本文对苯酚羟化用铁复合氧化物催化剂的失活情况进行了研究,考察了催化剂的寿命和催化剂活性随时间的变化关系,改变实验条件进行了催化剂活原因的分析。结果表明,催化剂8h左右开始失活,催化剂完全时间约为70h,催化剂失活的主要原因是由于活性组分从催化剂载体上流失引起。为了计算连续搅拌反应器中化催化剂的活性分布,便于反应器的设计和操作优化,关联了催化剂活性与时间的函数关系。 相似文献
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生物质催化热解获得生物油等高质产品是最有前途替代传统化石能源的方法之一,但在热解过程中存在着严重的催化剂失活问题,其中积炭是导致催化剂失活的最主要因素。本文对近年来生物质催化热解领域的催化剂积炭问题进行综述,重点介绍催化剂积炭失活原因及表征方法、积炭的影响因素分析(催化剂结构、催化剂酸性与反应温度)、抑制催化剂积炭的方法 (催化剂改性、高压反应条件等)以及积炭催化剂再生方法 (氧化灼烧再生、臭氧低温再生、非热等离子体再生等),并介绍了近年来新兴的微波催化热解技术对催化剂积炭的抑制和消除作用,然后针对该领域目前所面临的困难和发展方向进行展望,以期为生物质催化热解过程中催化剂积炭问题研究提供理论基础。 相似文献
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阐述了固体酸烷基化催化剂在异丁烷/丁烯烷基化中的再生方法研究进展,包括金属临氢再生、氧化煅烧再生、超临界流体再生、洗涤再生,同时对固体酸烷基化催化剂的失活原因和失活形式进行了分析评述。这些方法在一定条件下可以实现催化剂不同程度的再生,但由于操作以及成本等原因都停留在实验室阶段,本文综合比较了各种再生方法的再生工艺过程以及再生效果,分析各种再生方法的优劣。固体酸烷基化催化剂失活较快是阻碍异丁烷/丁烯固体酸烷基化工艺工业化的关键因素,研究探索操作简单、成本低、有效的固体酸烷基化催化剂再生方法仍将是今后该领域的研究热点。 相似文献
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常温COS水解催化剂失活原因与对策 总被引:7,自引:0,他引:7
采用XRD,压汞,微反-色谱等多种物理测试手段,对某化肥厂使用前后的水解催化剂的结构和性能进行了研究,指出催化剂失活的主要原因是催化剂表面沉积了大量硫和氯及其比表面下降,并提出了对策。 相似文献
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Deactivation regeneration and poison - resistant catalysts: commercial experience in stationary pollution abatement 总被引:1,自引:0,他引:1
The design of a commercial catalytic system requires considerable information on the operating conditions and environment in which the catalyst will function. Feed concentrations, flow rates, temperatures, pressures, and other measurements are necessary to establish a preliminary design for the required steady-state conversions. In addition, the catalyst and process design must be capable of functioning after experiencing upsets in any of the above mentioned variables. The most common causes of catalyst failure are thermal deactivation and poisoning by constituents in the gas stream.
This paper describes factors leading to deactivation of catalysts in commercial stationary abatement installations. Deactivated catalysts are returned and laboratory characterization methods are used to identify failure modes. These results are used to modify the catalyst, develop methods for regeneration and to recommend plant operating conditions. 相似文献
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Mercury-containing catalysts are widely used for acetylene hydrochlorination in China. Surface chemical characteristics of the fresh low-level mercury catalysts and spent low-level mercury catalysts were compared using multiple characterization methods. Pore blockage and active site coverage caused by chlorine-containing organics are responsible for catalyst deactivation. The reactions of chloroethylene and acetylene with chlorine free radical can generate chlorine-containing organic species. SiO2 and functional groups on activated carbon contribute to the generation of carbon deposition. No significant reduction in the total content of mercury was observed after catalyst deactivation, while there was mercury loss locally. The irreversible loss of HgCl2 caused by volatilization, reduction and poisoning of elements S and P also can lead to catalyst deactivation. Si, Al, Ca and Fe oxides are scattered on the activated carbon. Active components are still uniformly absorbed on activated carbon after catalyst deactivation. 相似文献
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