{"title":"Mechanism and model of n-decane pyrolytic coking based on the coupling of surface mass transfer and chemical reactions","authors":"Yuxiang Cheng, Pei-Xue Jiang, Yinhai Zhu","doi":"10.1016/j.cej.2025.161500","DOIUrl":null,"url":null,"abstract":"The pyrolytic coking of supercritical hydrocarbon fuels is a complex procedure involving various flow, mass transfer, and reaction processes, in which surface mass transfer plays a significant role. Pyrolytic coking experiments were conducted with n-decane in a pressure range of 3–5 MPa, a fuel conversion range of 0–0.62, and an operating time range of 5–40 min. The mass, morphology and graphitization degree of coke were studied using several characterization methods: temperature-programmed oxidation, scanning electron microscopy and Raman spectrometry. The coking mechanism based on the coupling of surface mass transfer and chemical reactions was revealed, and the cause of the coking mode transition was clarified. When the catalytic reaction rate was lower than the bulk diffusion rate, the coking mode was catalytic coking, and when the catalytic reaction rate was higher than the bulk diffusion rate, the coking mode was free radical growth coking. A coking model was established to calculate the transition diameter of the metal carbide particles corresponding to the coking mode transition and the proportion of the catalytic coking mode. The coke mass in the catalytic coking region can be calculated using this model, and the model results were consistent with the morphology and Raman spectroscopy characteristics. The mechanism and model will help in describing the coking process over a wide range of operating conditions and conducting more accurate simulations of regenerative cooling systems.","PeriodicalId":270,"journal":{"name":"Chemical Engineering Journal","volume":"89 1","pages":""},"PeriodicalIF":13.3000,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Engineering Journal","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1016/j.cej.2025.161500","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The pyrolytic coking of supercritical hydrocarbon fuels is a complex procedure involving various flow, mass transfer, and reaction processes, in which surface mass transfer plays a significant role. Pyrolytic coking experiments were conducted with n-decane in a pressure range of 3–5 MPa, a fuel conversion range of 0–0.62, and an operating time range of 5–40 min. The mass, morphology and graphitization degree of coke were studied using several characterization methods: temperature-programmed oxidation, scanning electron microscopy and Raman spectrometry. The coking mechanism based on the coupling of surface mass transfer and chemical reactions was revealed, and the cause of the coking mode transition was clarified. When the catalytic reaction rate was lower than the bulk diffusion rate, the coking mode was catalytic coking, and when the catalytic reaction rate was higher than the bulk diffusion rate, the coking mode was free radical growth coking. A coking model was established to calculate the transition diameter of the metal carbide particles corresponding to the coking mode transition and the proportion of the catalytic coking mode. The coke mass in the catalytic coking region can be calculated using this model, and the model results were consistent with the morphology and Raman spectroscopy characteristics. The mechanism and model will help in describing the coking process over a wide range of operating conditions and conducting more accurate simulations of regenerative cooling systems.
期刊介绍:
The Chemical Engineering Journal is an international research journal that invites contributions of original and novel fundamental research. It aims to provide an international platform for presenting original fundamental research, interpretative reviews, and discussions on new developments in chemical engineering. The journal welcomes papers that describe novel theory and its practical application, as well as those that demonstrate the transfer of techniques from other disciplines. It also welcomes reports on carefully conducted experimental work that is soundly interpreted. The main focus of the journal is on original and rigorous research results that have broad significance. The Catalysis section within the Chemical Engineering Journal focuses specifically on Experimental and Theoretical studies in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. These studies have industrial impact on various sectors such as chemicals, energy, materials, foods, healthcare, and environmental protection.