Issue 6, 2024

Influence of feed contamination on the conversion of heavy reformate and toluene over a composite hierarchical zeolite catalyst

Abstract

The effect of feed contaminants on the conversion of heavy reformate and toluene mixture over a catalyst containing 4 wt% Mo impregnated on a bifunctional hierarchical composite of mordenite and ZSM-5 is reported. Specifically, the effects of contaminants in the feed (water, 1,2,4,5-tetramethylbenzene (1245-TeMB) and indene) and contaminants in hydrogen (H2S and CO) were investigated through catalytic performance tests in a fixed-bed micro-reactor at 350 °C and 20 bar H2. The presence of >35 ppm water in the feed caused significant reduction in the dealkylation of methylethylbenzenes (MEBs) due to a decrease in catalyst's acidity. Hence a dried feed (containing 35 ppm water) was used. An increase of 1.2 wt% in the formation of xylenes was observed with the introduction of 10 wt% 1245-TeMB in the feed due to an increase in the methyl/ring ratio. The addition of 1 wt% indene in the feed resulted in a 4 wt% drop in the formation of xylenes due to the preferential adsorption of indene. The tests with 50 ppm H2S and 50 ppm CO in hydrogen showed a drop of about 2 wt% in the formation of xylenes. However, the weak basicity of CO exhibited a much lower impact than the adsorption of H2S on the dealkylation. The effects of these contaminants are discussed in the light of changes observed in product composition during the introduction of a contaminant (48 h) and after restoring the baseline conditions (48 h).

Graphical abstract: Influence of feed contamination on the conversion of heavy reformate and toluene over a composite hierarchical zeolite catalyst

Article information

Article type
Paper
Submitted
18 Nov 2023
Accepted
12 Feb 2024
First published
13 Feb 2024

React. Chem. Eng., 2024,9, 1433-1443

Influence of feed contamination on the conversion of heavy reformate and toluene over a composite hierarchical zeolite catalyst

S. A. Ali, Z. S. Qureshi, V. V. R. K. Tammana, A. N. Jishi, M. AlAmer and T. A. Mohammad, React. Chem. Eng., 2024, 9, 1433 DOI: 10.1039/D3RE00624G

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