In this work,a molecular-level kinetic model was built to simulate the vacuum residue(VR)coking process in a semi-batch laboratory-scale reaction kettle.A series of reaction rules for heavy oil coking were summarized ...In this work,a molecular-level kinetic model was built to simulate the vacuum residue(VR)coking process in a semi-batch laboratory-scale reaction kettle.A series of reaction rules for heavy oil coking were summarized and formulated based on the free radical reaction mechanism.Then,a large-scale molecularlevel reaction network was automatically generated by applying the reaction rules on the vacuum residue molecules.In order to accurately describe the physical change of each molecule in the reactor,we coupled the molecular-level kinetic model with a vapor–liquid phase separation model.The vapor–liquid phase separation model adopted the Peng-Robinson equation of state to calculate vapor–liquid equilibrium.A separation efficiency coefficient was introduced to represent the mass transfer during the phase separation.We used six sets of experimental data under various reaction conditions to regress the model parameters.The tuned model showed that there was an excellent agreement between the calculated values and experimental data.Moreover,we investigated the effect of reaction temperature and reaction time on the product yields.After a comprehensive evaluation of the reaction temperature and reaction time,the optimal reaction condition for the vacuum residue coking was also obtained.展开更多
Heavy oil is treated as an undesirable raw material in traditional refining markets because of its low yield.However,its rich natural aromatic structure and heteroatomic compounds make it possible to be a precursor to...Heavy oil is treated as an undesirable raw material in traditional refining markets because of its low yield.However,its rich natural aromatic structure and heteroatomic compounds make it possible to be a precursor to large-scale production of carbon materials.Using heavy oil and three SDA products as precursors,we synthesized highly fluorescent multi-color carbon dots(CDs)by hydrothermal method,which can precisely control the photoluminescence wavelength in the range of 350-650 nm.The synthesized carbon dots have the advantages of good long-term stability and stability under extreme pH conditions and low price.Importantly,the carbon dots synthesized with asphalt as the precursor have the highest fluorescence quantum yield.X-ray photoelectron spectroscopy(XPS)is used to elucidate the effects of different precursor on emission color change and photoluminescence quantum yield(PLQY),thus providing a controlled tuning of the system for the functionalization of CDs.And we further used the CDs in macrophage labeling.This pathway gives a reliable and repeatable industry possibility and may boost the applications of CDs into reality.展开更多
Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking...Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic techniques.High relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and naphthobenzothiophenes.Coking liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).However,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process.The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.展开更多
基金supported by the National Natural Science Foun-dation of China(22021004 and U19B2002).
文摘In this work,a molecular-level kinetic model was built to simulate the vacuum residue(VR)coking process in a semi-batch laboratory-scale reaction kettle.A series of reaction rules for heavy oil coking were summarized and formulated based on the free radical reaction mechanism.Then,a large-scale molecularlevel reaction network was automatically generated by applying the reaction rules on the vacuum residue molecules.In order to accurately describe the physical change of each molecule in the reactor,we coupled the molecular-level kinetic model with a vapor–liquid phase separation model.The vapor–liquid phase separation model adopted the Peng-Robinson equation of state to calculate vapor–liquid equilibrium.A separation efficiency coefficient was introduced to represent the mass transfer during the phase separation.We used six sets of experimental data under various reaction conditions to regress the model parameters.The tuned model showed that there was an excellent agreement between the calculated values and experimental data.Moreover,we investigated the effect of reaction temperature and reaction time on the product yields.After a comprehensive evaluation of the reaction temperature and reaction time,the optimal reaction condition for the vacuum residue coking was also obtained.
基金Beijing Nova Program Interdisciplinary Studies Cooperative Project(No.Z181100006218138)Science Foundation of China University of Petroleum(Nos.2462020YXZZ018,2462019QNXZ02,2462018BJC004)for the support。
文摘Heavy oil is treated as an undesirable raw material in traditional refining markets because of its low yield.However,its rich natural aromatic structure and heteroatomic compounds make it possible to be a precursor to large-scale production of carbon materials.Using heavy oil and three SDA products as precursors,we synthesized highly fluorescent multi-color carbon dots(CDs)by hydrothermal method,which can precisely control the photoluminescence wavelength in the range of 350-650 nm.The synthesized carbon dots have the advantages of good long-term stability and stability under extreme pH conditions and low price.Importantly,the carbon dots synthesized with asphalt as the precursor have the highest fluorescence quantum yield.X-ray photoelectron spectroscopy(XPS)is used to elucidate the effects of different precursor on emission color change and photoluminescence quantum yield(PLQY),thus providing a controlled tuning of the system for the functionalization of CDs.And we further used the CDs in macrophage labeling.This pathway gives a reliable and repeatable industry possibility and may boost the applications of CDs into reality.
基金supported by the National Natural Science Foundation of China(U1162204,21236009,21376262)
文摘Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic techniques.High relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and naphthobenzothiophenes.Coking liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).However,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process.The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.
