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• Molecular-level coupling simulation can describe complex reaction network in refinery. • Molecular matrix with structure and composition can transmit information among units. • Simulation can reveal reaction pathways and synergistic effect of molecules. For the highly integrated system in the petrochemical industry, establishing a coupling simulation model for the units that were closely related at the molecular level was a big challenge due to the difficulty of massive and effective data interaction. Based on the structure-oriented lumping (SOL) method, the molecular composition matrix, which included material molecular information quantitatively, made it possible to build up the coupling simulation model. An interoperable molecular composition matrix including 1228 row vectors connected the delayed coking model and the hydrotreating model in series. The coupling simulation model of delayed coking and hydrotreating process was established at the molecular level. In addition to predicting the molecular composition of the products, the simulation model could track the reaction path and reflect the synergistic transformation effect of hydrocarbon and non-hydrocarbon molecules. And the simulation model could also quantitatively calculate the influence of changes in upstream reaction conditions on downstream products. The coupling simulation model provided useful explorations to achieve the petroleum molecular management throughout the whole petrochemical process. [ABSTRACT FROM AUTHOR]

• A reaction model could predict coking product yields and molecular compositions. • The SIC method could calculate product properties based on molecular compositions. • The effects of structural increments on RON and CN could be quantitatively calculated. The delayed coking reaction kinetic model based on the structure-oriented lumping method showed good accuracy in predicting the yield and composition of coking products at the molecular level. Based on the basic law that molecular structure determines molecular properties, the structural increment contribution method was constructed to expand the functions of established reaction kinetic model to predict the characteristic properties of coking gasoline and diesel products: distillation range, density, research octane number (RON) or cetane number (CN). The contributions of different structural increments of hydrocarbon molecules in gasoline to the RON and those in diesel to the CN could also be calculated by the model. The RONs of the hydrocarbon molecules decreased with the increase of R , and increased with the increase of br and me for the coking gasoline. The CNs of the paraffins molecules improved with the increase of R , but reduced with the increase of br and A6 for the coking diesel. The effects of all structural increments on the RON and CN could be quantitatively calculated through the established correlation formulas. The prediction of composition and properties of coking gasoline and diesel based on the model could guide the subsequent processing and process optimization of delayed coking plant. [ABSTRACT FROM AUTHOR]

• A molecular-level model with good predictability for delayed coking was established. • The model could track the reaction path of any molecule in the reaction network. • Gasoline and diesel were represented by 173 and 1132 structural vectors respectively. • The molecules were classified into PONA according to the discriminant rules. • The effect of recycle ratio on the product distribution was described quantitatively. Based on the structure-oriented lumping method, a molecular-level reaction kinetic model of the delayed coking process, which adopted 24 structural increments to construct the feed molecular matrix containing 2944 molecules, was established with a reaction network containing 74,581 reactions using MATLAB. The reliability of the model was verified by experimental results. According to the discriminant rules of structural increments, 173 structural vectors in gasoline and 1132 structural vectors in diesel were classified into different group compositions, respectively. The model could track the reaction path of any specific molecule in the complex thermal cracking reaction network. The influences of operation conditions such as recycle ratio on the product distribution could be discovered through the calculation of the molecular-level model, which is helpful for the process optimization and precise regulation of product composition for the delayed coking plants. [ABSTRACT FROM AUTHOR]

• A molecular-level model for delayed coking process was established. • The conversion behavior of sulfur in delayed coking process was investigated. • The sulfur compounds in gasoline were expressed as 57 structural vectors. • The sulfur compounds were classified according to the discriminant rules. In order to describe the reaction network and investigate the conversion behavior of sulfur compounds in delayed coking process, a molecular-level reaction kinetic model was established with a reaction network consisting of 81,081 reactions based on the structure-oriented lumping method. A feed molecular matrix containing 2,944 structural vectors was constructed with 24 structural increments based on the characteristics of the vacuum residue molecular composition. The reliability of the model was verified by industrial data. Through the calculation of the SOL model, the sulfur compounds in gasoline were expressed as 57 structural vectors, which were divided into thiophenes, mercaptans and thioethers according to the discriminant rules. The conversion law of sulfur compounds was investigated by tracking the reaction path of molecules in the reaction network. The SOL model could calculate the distribution of sulfur compounds in coking gasoline. The contents of thiophene molecules increased with the carbon numbers. Ethyl mercaptan and propyl mercaptan had higher content in mercaptans. The SOL model can reveal the influences of reaction conditions on sulfur compounds conversion in delayed coking process at the molecular level, which contributes to the accurate control of sulfur content in coking gasoline. [ABSTRACT FROM AUTHOR]