Investigation of the problems with using gas adsorption to probe catalyst pore structure evolution during coking.
Investigation of the problems with using gas adsorption to probe catalyst pore structure evolution during coking.
复制标题
研究利用气体吸附探测焦化过程中催化剂孔结构演变的问题。
DOI：
10.1016/j.jcis.2012.10.025
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发表时间：
2013
影响因子：
9.9
通讯作者：
Gopinathan N
中科院分区：
文献类型：
--
作者：
Gopinathan N
了解多相催化剂结焦机理的一种常用方法是通过对排出球团的气体吸附分析来监测孔隙结构的演变。然而，气体吸附数据分析的标准方法，为了获得孔径分布，关键假设是热力学无关的孔隙。这一假设忽略了合作吸附现象的可能性，这将是研究焦化催化剂时的一个关键问题。在这项工作中，连续吸附技术被用来检测和评估在焦化催化剂内的吸附协同效应的程度。以癸烷在加氢催化剂上的反应为例进行了研究。研究表明，传统的分析方法对焦化过程中孔隙结构变化的描述存在缺陷。对于本研究中考虑的案例研究，发现协同吸附效应意味着26%的测量吸附发生在比传统分析假设的三倍大的孔隙中。因此，连续吸附技术为焦化过程中孔隙结构演化提供了重要的附加信息。吸附动力学的研究已被用来推断关于焦化过程在球团内的一般空间位置的信息。
A common approach to try to understand the mechanism of coking in heterogeneous catalysts is to monitor the evolution of the pore structure using gas adsorption analysis of discharged pellets. However, the standard methods of analysis of gas adsorption data, to obtain pore-size distributions, make the key assumption of thermodynamically-independent pores. This assumption neglects the possibility of co-operative adsorption phenomena, which will shown to be a critical problem when looking at coking catalysts. In this work the serial adsorption technique has been used to detect and assess the extent of co-operative effects in adsorption within coking catalysts. The reaction of decane over a hydroprocessing catalyst was used as a case study. It has been shown that the conventional analysis method would lead to a flawed picture of the pore structure changes during the coking process. For the case-study considered in this work, it was found that co-operative adsorption effects meant that 26% of the measured adsorption was occurring in pores up to three times larger than the size conventional analysis would presume. The serial adsorption technique was thus shown to provide important additional information on pore structure evolution during coking. A study of the kinetics of adsorption has been used to infer information about the general spatial location of the coking process within a pellet.