Effect of Bed Height on the Performance of a Fixed Mo/HZSM‐5 Bed in Direct Aromatization of Methane

Xu, Yuebing; Song, Yang; Liu, Xiaohao; Zhang, Zhanguo

doi:10.1002/ceat.201600178

Cited by 10 publications

(3 citation statements)

References 175 publications

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“…Even though higher residence time leads to higher coke formation in comparison to aromatics formation, the cumulative amount of coke formed is more for a lower number of parallel reactors due to higher cumulative CH 4 feed flow (for the entire cycle) to the catalyst ratio. Similar observations are reported by Xu et al, 57 where they studied the effect of superficial velocity on lifetime aromatics productivity and coke formation in a fixed bed reactor for different bed heights.…”

Section: Resultssupporting

confidence: 87%

Multiscale Modeling of a Direct Nonoxidative Methane Dehydroaromatization Reactor with a Validated Model for Catalyst Deactivation

Mevawala

Bai

Kotamreddy

et al. 2021

Ind. Eng. Chem. Res.

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Due to the recent boom in shale gas production, aromatics production using direct nonoxidative methane dehydroaromatization (DHA) is being investigated extensively. However, due to rapid coke formation, catalysts in the nonoxidative methane DHA reactors get deactivated, which is one of the critical issues for the commercial success of the methane DHA process. In this paper, a model for catalyst deactivation is developed. Rate models for other DHA reactions are developed by considering the decrease in the catalyst activity with time. Due to the very fast coke formation rate on the fresh catalyst, there is coke formation immediately upon the introduction of the feed. Therefore, an algorithm is developed for estimation of the initial state of the reactor and the kinetic parameters by coupling an iterative direct substitution approach with an optimization approach. Transient experimental data from an in-house reactor are first reconciled and then used for developing the kinetic model including the coke formation model. Using the rate model, a dynamic, heterogeneous, multiscale reactor model with embedded heating is developed. The model couples the catalyst pellet level model with a reactor level model. Impacts of temperature, L/D ratio, and scheduling of reactors on variability in conversion and yield with time are studied.

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Section: Resultssupporting

confidence: 87%

Multiscale Modeling of a Direct Nonoxidative Methane Dehydroaromatization Reactor with a Validated Model for Catalyst Deactivation

Mevawala

Bai

Kotamreddy

et al. 2021

Ind. Eng. Chem. Res.

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“…A combination of Mo 2 C with ZSM-5 exhibits unique performance for the aromatization of lower alkanes 9 , 10 . This catalyst family has demonstrated high flexibility in adjusting composition and performance 11 , e.g., Mo loading (2–6 wt%), Si/Al ratios (10–25) and temperature (700–800 °C), methane conversion from 7% to 17% and benzene selectivity from 50% to 80% 8 , 12 – 15 . However, the challenge remains mainly on the limited thermodynamics for higher conversion and serious coking, which is a ubiquitous obstacle for the application of Mo/zeolite catalysts.…”

Section: Introductionmentioning

confidence: 99%

Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst

Zhu,

Bian,

Liu

et al. 2024

Nat Commun

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Non-oxidative methane dehydro-aromatization reaction can co-produce hydrogen and benzene effectively on a molybdenum-zeolite based thermochemical catalyst, which is a very promising approach for natural-gas upgrading. However, the low methane conversion and aromatics selectivity and weak durability restrain the realistic application for industry. Here, a mechanism for enhancing catalysis activity on methane activation and carbon-carbon bond coupling has been found to promote conversion and selectivity simultaneously by adding platinum–bismuth alloy cluster to form a trimetallic catalyst on zeolite (Pt-Bi/Mo/ZSM-5). This bimetallic alloy cluster has synergistic interaction with molybdenum: the formed CH3* from Mo2C on the external surface of zeolite can efficiently move on for C-C coupling on the surface of Pt-Bi particle to produce C2 compounds, which are the key intermediates of oligomerization. This pathway is parallel with the catalysis on Mo inside the cage. This catalyst demonstrated 18.7% methane conversion and 69.4% benzene selectivity at 710 °C. With 95% methane/5% nitrogen feedstock, it exhibited robust stability with slow deactivation rate of 9.3% after 2 h and instant recovery of 98.6% activity after regeneration in hydrogen. The enhanced catalytic activity is strongly associated with synergistic interaction with Mo and ligand effects of alloys by extensive mechanism studies and DFT calculation.

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“…For methane nonoxidative utilization, methane direct aromatization based on Mo/ZSM-5 catalyst has been extensively studied. − Owing to the high structural stability of methane, the catalyst performance, e.g., methane conversion and aromatics yields, is so low that makes it far from attracting industry’s interest.…”

Section: Introductionmentioning

confidence: 99%

Two-Step Process for Feasible Conversion of Ethane to Aromatics: Concept and Demonstration

Zhang¹,

Wang²,

Miles³

et al. 2021

Ind. Eng. Chem. Res.

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Direct conversion of light alkanes, specifically ethane to aromatics, has been an important research goal for both academia and industry over the past several decades. Despite a significant research investment, there have been no major technical breakthroughs to date, due in large part to the inability to develop catalysts with satisfactory performance. This article proposes a two-step process concept for aromatics production from ethane that has the potential to address this impasse. Our process involves performing the dehydrogenation of ethane in a first step, followed by ethylene aromatization in a separate reactor. We begin by reviewing the major fundamental and technical hurdles associated with efforts to develop one-step processes and use this to show how our two-step process can overcome limitations in the reaction pathway, thermodynamics, and catalyst performance encountered in the one-step approach. We then describe catalyst validation, reactor design, and process economics to illustrate the value of our concept.

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Effect of Bed Height on the Performance of a Fixed Mo/HZSM‐5 Bed in Direct Aromatization of Methane

Cited by 10 publications

References 175 publications

Multiscale Modeling of a Direct Nonoxidative Methane Dehydroaromatization Reactor with a Validated Model for Catalyst Deactivation

Multiscale Modeling of a Direct Nonoxidative Methane Dehydroaromatization Reactor with a Validated Model for Catalyst Deactivation

Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst

Two-Step Process for Feasible Conversion of Ethane to Aromatics: Concept and Demonstration

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