Study on the deactivation mechanism of HZSM-5 in the process of catalytic cracking of n-hexane

He, Mu; Ali, Muhammad-Faryad; Song, Yueqin; Zhou, Xiaolong; Wang, Jinan; Nie, Xinyao; Wang, Zheng

doi:10.1016/j.cej.2022.138793

Cited by 17 publications

(3 citation statements)

References 51 publications

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“…Abundant acidic sites (low Si/Al ratio) may cause excessive coupling reaction of aryl groups through a carbonium ion reaction mechanism. Mild Brønsted acidity assists in the inhibition of β-scission and coke formation ( 32 , 33 ). In addition to its remarkable activity and product selectivity, HZSM-5(160) demonstrated excellent resistance to coke deposition, unlike other zeolites (HMOR, HBeta, and HY).…”

Section: Resultsmentioning

confidence: 99%

Coupled conversion of polyethylene and carbon dioxide catalyzed by a zeolite–metal oxide system

Liu,

Ma,

Tian

et al. 2024

Sci. Adv.

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Zeolite-catalyzed polyethylene (PE) aromatization achieves reduction of the aromatic yield via hydrogenation and hydrogenolysis reactions. The hydrogen required for CO 2 hydrogenation can be provided by H radicals formed during aromatization. In this study, we efficiently convert PE and CO 2 into aromatics and CO using a zeolite–metal oxide catalyst (HZSM-5 + CuZnZrO x ) at 380°C and under hydrogen- and solvent-free reaction conditions. Hydrogen, derived from the aromatization of PE over HZSM-5, diffuses through the Brønsted acidic sites of the zeolite to the adjacent CuZnZrO x , where it is captured in situ by CO 2 to produce bicarbonate and further hydrogenated to CO. This favors aromatization while inhibiting hydrogenation and secondary hydrogenolysis reactions. An aromatic yield of 62.5 wt % is achieved, of which 60% consisted of benzene, toluene, and xylene (BTX). The conversion of CO 2 reaches values as high as 0.55 mmol g PE −1 . This aromatization–hydrogen capture pathway provides a feasible scheme for the comprehensive utilization of waste plastics and CO 2 .

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Section: Resultsmentioning

confidence: 99%

Coupled conversion of polyethylene and carbon dioxide catalyzed by a zeolite–metal oxide system

Liu,

Ma,

Tian

et al. 2024

Sci. Adv.

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“…Its fundamental principle involves establishing dynamic mathematical models from process data to predict system dynamic behavior and response. The analysis of operating variables, advanced control, and online optimization in CCU heavily relies on dynamic mathematical models that describe the process [6,7]. In recent years, an increasing number of studies have applied SMI methods in modeling, predictive modeling, and loop control of CCU to achieve accurate modeling and optimization control of this complex process [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

An Adaptive-Noise-Bound-Based Set-Membership Method for Process Identification of Industrial Control Loops

Wang,

Zhang

2023

Processes

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Modeling of key variable data needs to consider the complex characteristics of systems in the catalytic cracking unit (CCU) of petroleum refining process, such as slow time-varying behavior, complex dynamic properties, distributed traits, and unknown stochastic noise. To fully capture the dynamics of a linear ordinary dynamic process without introducing incremental components, an adaptive-noise-bound-based set-membership method (RSMI) is proposed in this paper. Under the set-membership framework, the output set is typically represented as an ellipsoid based on the assumed conditions. Firstly, a CARMA model is considered; longer-duration historical data are selected to capture the intricate dynamic characteristics of industrial control loops. Secondly, RSMI introduces am approach to determine allowance factor, optimizing the noise bound for better suitability in real-world noise environments. The adaptive noise bound is achieved by designing an optimization algorithm that seeks the optimal parameters within the optimization framework. The stability of the RSMI algorithm is demonstrated through the application of the Lyapunov method. Next, the RSMI algorithm has been applied in engineering practice and designed for offline and online training stages of control processes. Finally, simulation experiments are performed to model and predict real-time data of flow, pressure, and liquid-level control loops within a catalytic cracking unit. Furthermore, the effectiveness of the RSMI algorithm is validated through two general examples, and frequency domain analysis is performed.

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“…The catalytic cracking reaction of hydrocarbon molecules on molecular sieves produces a variety of substances, and the reaction network was very complex. There were many studies on the cracking mechanism of alkanes and olefins [17][18][19][20][21][22]. Corma et al [23] studied the reaction effects of n-heptane, n-decane, n-dodecane and n-tetradecane on USY, β and ZSM-5.…”

Section: Introductionmentioning

confidence: 99%

Effect of Molecular Structure of C10 Hydrocarbons on Production of Light Olefins in Catalytic Cracking

Han

2023

Catalysts

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The effect of the molecular structure of feedstock on the cracking reaction of C10 hydrocarbons to ethylene and propylene over H-ZSM-5 zeolite was investigated. To better compare the effect of decane on the production of light olefins, the thermal cracking and catalytic cracking performance of decane were first investigated. As a comparison, the thermal cracking and catalytic cracking of decane were studied by cracking over quartz sand and H-ZSM-5. Compared with the thermal cracking reaction over quartz sand, the catalytic cracking reaction of decane over H-ZSM-5 has a significantly higher conversion and light olefins selectivity, especially when the reaction temperature was lower than 600 °C. On this basis, the catalytic cracking reactions of decane and decene over H-ZSM-5 were further compared. It was found that decene with a double bond structure had high reactivity over H-ZSM-5 and was almost completely converted, and the product was mainly olefin. Compared with decane as feedstock, it has a lower methane yield and higher selectivity of light olefins. Therefore, decene was more suitable for the production of light olefins than decane. To this end, we designed a new light olefin production process. Through olefin cracking, the yield of light olefins in the product can be effectively improved, and the proportion of different light olefins such as ethylene, propylene and butene can be flexibly adjusted.

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Study on the deactivation mechanism of HZSM-5 in the process of catalytic cracking of n-hexane

Cited by 17 publications

References 51 publications

Coupled conversion of polyethylene and carbon dioxide catalyzed by a zeolite–metal oxide system

Coupled conversion of polyethylene and carbon dioxide catalyzed by a zeolite–metal oxide system

An Adaptive-Noise-Bound-Based Set-Membership Method for Process Identification of Industrial Control Loops

Effect of Molecular Structure of C10 Hydrocarbons on Production of Light Olefins in Catalytic Cracking

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