Balanced Fast-SpaciMS capillary configurations provide practically noninvasive channel-average measurements in catalytic monoliths

• Published in: Chemical engineering science Vol. 282; no. 9; p. 119272
• Main Authors: Hlavatý, Tomáš, Kočí, Petr, Isoz, Martin, Deka, Dhruba, Partridge, William
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 05.12.2023; Elsevier
• Subjects: CFD; CO oxidation; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; SpaciFTIR; SpaciMS; Three-way catalyst; CFD; SpaciMS; SpaciFTIR; Three-way catalyst; CO oxidation
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2023.119272

Spatially resolved capillary-inlet mass spectrometry (SpaciMS) provides a detailed picture of the spatiotemporal evolution of reaction network in catalytic monoliths. In the present work, we combine the SpaciMS experiments with a newly developed non-isothermal 3D CFD model for heterogeneously catalyzed reactive flows, including diffusion and permeation through the coated catalyst and channel wall. We explore how the capillary size and sampling rate can be balanced to minimize the impact on probed-channel conversions and provide species concentration measurements representative of the free channel average. In all studied configurations, the balanced sampling-rate fraction is noticeably higher than the corresponding capillary occlusion fraction. For a typical 350-micron capillary that occupies 11% of the channel cross- section, the balanced sampling rate represents 43% of the channel flow. The present work shows that together, a balanced SpaciMS configuration and numerical simulation provide accurate channel-averaged information of a monolithic catalyst under realistic operation conditions. •Spatially distributed intra-catalyst CO conversion profiles measured by SpaciMS.•Invasiveness of the sampling capillary studied by non-isothermal CFD simulations.•Heat and mass transport (diffusion, permation) between the channels included.•Results validated by experiments with varied capillary thickness and sampling rate.•Balanced sampling rates were identified for unbiased channel-average measurements.