In the hydrodenitrogenation reaction, metals such as Fe, Co, and Ni are frequently incorporated as promoters into the MoS2 catalyst. Exploring the reasons for the differences in catalytic activity within multi-metal catalysts is crucial for designing novel hydrodenitrogenation catalysts. Herein, first-principles calculations were used to analyze the action mechanism of NiMoS, CoMoS, and FeMoS catalysts in the hydrodenitrogenation of carbazole. The findings demonstrate that the smaller number of outer-layer electron holes of Ni atoms results in a weaker binding force on S atoms, thereby facilitating the formation of reactive sites. Meanwhile, the NiMoS catalyst exhibits the highest hydrogenation activity for carbazole and intermediates, attributable to the electronic properties of the Ni atom surface, followed by CoMoS, and FeMoS shows the lowest activity. In addition, the S-edge of all catalysts exhibited higher hydrogenation activity compared to the Mo-edge. It is noteworthy that the FeMoS catalyst demonstrates the highest C-N bond cleavage activity, a consequence of the strong interaction between Fe atoms and H beta. Furthermore, as carbazole undergoes hydrogenation to form dodecahydrocarbazole, the increase in steric hindrance substantially impedes the C-N bond cleavage, particularly the E2 elimination process.

The appropriate electronic structure of catalysts is vital for the slurry phase hydrocracking activity of inferior vacuum residue. Herein, a series of chemically bonded oil-soluble bimetallic FeMo catalysts with excellent performance were prepared by a novel strategy. Both experimental and density functional theory (DFT) calculations were conducted to investigate the regulatory effect of Fe on MoS2. It was found that the incorporation of Fe can reduce the average length and stacking layers of the MoS2 catalyst by 16.7% and 20.0%, respectively, thus exposing more active sites. Meanwhile, XPS, Raman and EXAFS results show that Fe transfers electrons to Mo to form electron-rich MoS2 and generate more defect sites on the surface of the FeMoS catalyst. For the VR hydrocracking activity test, it was demonstrated that the electron-rich MoS2 catalyst exhibits excellent performance, with the coke yield reduced by 32.0% and the total conversion rate of resin and asphaltene increased by 13.5%. Moreover, DFT results further reveal that the electrons transfer from Fe to Mo induces the change of chemical properties of the MoS2 surface and the adjustment of the d-band center, which promotes the migration of H and reduces the generation energy of coordinatively unsaturated sites. This study provides valuable insights into the design and upgrading of prominent oil-soluble bimetallic catalysts for slurry phase hydrocracking.

To overcome the limitations of traditional experimental"trial and error"methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely"high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)".Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.

Increasing gasoline production in FCC unit can improve the utilization efficiency of petroleum resources and gain economic benefit. This paper discusses the technical principles for increasing FCC gasoline yield from the aspects of feedstock properties, operating conditions, LCO (light cycle oil) recycling, catalyst selection and reactor type, and illustrates the industrial application examples for maximizing gasoline production. The technical measures, such as optimizing the feedstock, properly increasing the catalyst activity and reaction temperature, recycling LCO or hydrotreated LCO, applying high gasoline yield catalyst, and adopting the two-zone riser reactor, are proposed to enhance the gasoline yield.

Chain initiation reactions in the oxidation process of lubricant base stock molecules were studied by molecular simulations. Two ways to initiate lubricant oxidation were investigated. They included the dissociation of chemical bonds in base stock molecules and the reaction between base stock molecules and oxygen (O-2), respectively. Reaction activation energy of above methods was calculated. The results show that C-C bonds are more likely to break than C-H bonds to generate free radicals by the pyrolysis of chemical bonds. The C-C bonds with tertiary carbon atoms are preferential positions to crack. However, their bond dissociation energy is above 360 kJ/mol, which is difficult to occur under lubricant working conditions. The chain initiation is more likely to occur by the way that O-2 attacks the two atoms in C-H bonds at the same time, and is then embedd(ed into the C-H bond to produce hydrocarbon peroxides. And then, the O-O bond is cracked to form hydroxyl radicals and alkoxy radicals. The C-H bonds with tertiary carbon atoms are preferential reaction sites, the reaction activation energy of which is about 190.11 kJ/mol.

The mobility and aggregation behavior of macromolecular lubricant oxidation products and their influences on the performance of base stock were probed by molecular dynamics (MD) simulation. The mean square displacement (MSD) of molecules was calculated to explore the mobility of molecules. The distribution appearance of lubricant oxidation products in models was acquired to explore the aggregation of molecules. The results show that the mobility of macromolecular oxidation products is lower than that of base stock. The MSD of macromolecular oxidation products reduces with an increasing macromolecular weight. Macromolecular oxidation products can also decrease the mobility of base stock. The interaction energy between the macromolecules and the base stock soars with the increase of macromolecular weight. Macromolecules with a larger molecular weight can affect more base stock molecules with stronger restriction, which leads to lower mobility of base stock molecules. There are aggregates formed among macromolecular oxidation products, and the molecules in aggregates are connected by hydrogen bonds. The quantity of hydrogen bonds in aggregates is related to temperature.

By using molecular dynamics simulations based on the classical mechanic method, the dispersion behavior of gasoline detergent in deposit aggregation system was investigated. The representative simulation relating to the deposit molecules and the gasoline detergent molecules with high market share were selected as the model compounds. The microscopic mechanism of dispersing function of gasoline detergent was revealed in detail. It was found that due to Einterac(depo-depo)>Einteraction(gaso-gaso)>Einteraction(gaso-depo), the deposits were driven to gradually aggregate themselves in the gasoline medium. The relative strong interaction between characteristic groups in detergent molecules and deposits could weaken the interaction between deposit aggregates, which mainly comes from the Van der Waals force, the electrostatic interaction, and the orbital interaction. In order to play the dispersing role of detergent, the main factor is to enhance the interaction between the gasoline detergent and the deposit appropriately from the viewpoint of molecular structure design.

In this paper, the stoichiometric mechanism of gas phase oxidation process of gasoline hydrocarbons was studied through using theoretical stoichiometry. The reason of the phenomenon of cold flame and negative temperature coefficient in the reaction of hydrocarbon molecules before the flame was explained from the molecular level. During the gas phase oxidation process, the alkoxy radical RO· reacts with hydroxyl ·OH to form a relatively stable intermediate such as aldehyde (or ketone) and H 2 O molecules, and the free radical chain reaction process.The temperature of the reaction process is very low, while the release of a large number of heat, the formation of aldehydes (or ketones) from the excited state back to the ground state when the emission of about 400nm wavelength of light blue fluorescence.

Different kinds of base oils with different viscosity were analyzed in this paper, including eight mineral base oils, alkylnaphthalene and three synthetic PAO oils. The influence of different hydrocarbon molecules on physical properties of mineral base oils was investigated, such as density (d), kinematic viscosity (KV), viscosity index (VI), etc. Possible reasons for some inconsistent phenomena in data processing were also theoretically analyzed in detail. The refractive indexes (RI), d and molecular weight (M) decrease linearly with the increase of paraffinic content other than KV, which declines exponentially. There are no clear relationships between physical properties of base oils and naphthenic content, while polycyclic alkanes show a strong correlation with M and KV. The influence of aromatics on physical properties of base oils is just the opposite of paraffin's. VI of the base oils with low aromatics content increases linearly as their paraffinic contents rise when their carbon numbers are approximately equal. However, base oils with high aromatics content follow an utterly different rule, in which VI declines dramatically linearly with the increase in polycyclic aromatic content, which is the essential reason why naphthenic base oils all have terrible viscosity-temperature characteristics while paraffinic base oils usually do not.

To study all kinds of elementary reactions at the level of gasoline hydrocarbon molecules has always been a core content of basic combustion research, but for a long time, studies often focus on the physical process in cylinder and don't go deep into chemical details about the molecular structure and combustion mechanism of fuel, thereby restricting the feasibility to seek control and optimize combustion process from the perspective of chemical reaction. In this paper, we study the chain initiation reaction mechanism in the high temperature oxidation process of gasoline C8 hydrocarbon molecules and explain the relationship between the structure of hydrocarbon molecules and the middle-chain initiation characteristics of pre-flame reaction of hydrocarbon molecules at a molecular level using a theoretical chemical method. It is of great significance for petroleum refining and engine designers.

The dimensions of the rigid groups in the VGO model compounds and the dimensions of VGO molecules are calculated by using molecular simulation techniques.Dynamics methods were applied to investigate the diffusion process of VGO compounds at 800 K in FAU zeolite.The diffusibility difference of different VGO model compounds was studied by calculated penetration distance.The results indicated that the carbon chain length of VGO molecule and the dimensions of rigid group are the main factors that influence the diffusion ability of VGO in FAU zeolite.The increase in chain length leads to a lower diffusion ability due to the crimp of VGO molecules.The increase in ring number in naphthene and aromatics or the branched chain in the molecule increases the minimum cross-section size of the molecular rigid group of the hydrocarbon molecules,thus reducing the diffusion ability of the hydrocarbon molecules.When the hydrocarbon mixed with polycyclic aromatics as a model,the diffusion ability of the easy diffused molecules is lowered due to pore block by polycyclic aromatics.

Molecular simulation methods were used to study the adsorption of different types of hydrocarbons (2-olefins,aromatics,alkanes and cycloalkanes with carbon chain of C14,C22,C30) on H-FAU zeolite.The results show that the adsorption energy increases as the chain length extends from 14 to 30.The π-H bond is formed between the Bronsted acid sites on the zeolite and the π-electronics of olefins and aromatics,while Van der Waals interaction exists between zeolite framework and molecules through the electronic induction between Bronsted acid sites and σ-electronics of alkanes and cycloalkanes.The increase of carbon number in molecular chain has little effect on π-H interaction or electronic induction interaction,but increases the Van der Waals interactions.The intensity of interactions between molecules and acid sites decreases in the following order:olefins＞aromatics＞alkanes＞cycloalkanes.

Using molecular dynamics simulations based on classical mechanic method, the mechanism of competitive adsorption between gasoline detergent and deposit on Fe（110） surface was investigated. The representative simulation relating to the deposit molecule and the gasoline detergent molecule with high market share were selected as the model compound. It was found that when the detergent and deposit molecules exist at the same time, the detergent molecules would compete with the deposit molecules to reduce the adsorption of the deposit on Fe（110） so as to protect the metal surface. In addition, the ESP distribution is further confirmed that the detergent molecule has higher adsorption ability than the deposit molecule with the DFT theory. The essence of competitive adsorption is further revealed in detail, which is very important for the development of new type high-efficiency detergent additives.

Composition distribution of a typical commercial gasoline more representative in current market which also meets China V gasoline standard is discussed.The octane number distribution and vapor pressure distribution of the commercial gasoline is also analyzed.In addition, the hydrocarbon making a larger contribution to the octane number or vapor pressure is reached.The results indicate that the commercial gasoline more representative in the current market mainly includes i-paraffin, aromatics and a small amount of olefins in order to meet the China V gasoline standard.Olefin is the main composition which contributes to the octane number and vapor pressure for the light fraction of commercial gasoline.However, in order to meet the V gasoline standards, the olefin content decreases so greatly that we have to add a certain amount of MTBE to make up for the octane value loss and vapor pressure loss of the commercial gasoline.Aromatics are the components that contribute to the octane number for heavy fraction of commercial gasoline.However, the octane number of the middle distillate is relatively absent.In order to satisfy the good combustion performance of commercial gasoline, it is very important to improve the distribution of octane number by adjusting the gasoline component.

N-dodecane,butyl-cyclohexane,tetralin,decalin,and their mixtures were used as the model compounds and the combined techniques of FCC test and molecular simulation were adopted to study the reasons for a lot of uncracked chain alkane existing in FCC slurry. It is found that alkanes have different cracking performance in their single state or in a mixed one. When the alkane is mixed with strong hydrogen-donating molecules,like tetralin or decalin,the conversion of alkane is signifi-cantly depressed. Based on the results of experiment and molecule simulation,and reaction chemistry,a conclusion can be drawn that the hydride transfer between hydrocarbon molecules is the main reason that results in a lot of saturated,uncracked chain alkane in FCC slurry.

在550℃、常压、加入水蒸气的条件下,研究稀土La和Ce改性ZSM-5分子筛上FCC汽油的催化裂解反应.结果表明,稀土La和Ce改性可以提高ZSM-5分子筛的总酸量和强酸量,从而使FCC汽油转化率,特别是烯烃裂解反应的转化率明显提高,烯烃反应的选择性和气相产物乙烯、丙烯、丁烯,特别是丙烯的选择性显著增加.分子模拟计算结果表明,La3+和Ce4+位于ZSM-5分子筛Z型孔道的拐弯处,距离孔壁的距离为0.3～0.4 nm,使得弯道处的体积明显减小,导致烯烃裂解反应能垒、环化反应能垒、叠合反应能垒均有不同程度的增加,但裂解反应能垒增加的幅度最小,从而提高了烯烃裂解反应的选择性.

采用变温超极化129Xe NMR技术,结合XRD、29Si NMR以及N2吸附-脱附表征手段,分析了稀土改性Y型分子筛REHY的孔洞结构及稀土离子在分子筛中的分布特征.结果表明,129Xe NMR谱中存在2个明显的信号峰,为129Xe分子在2种不同环境孔洞中快速交换的结果,即分子筛存在2种不同环境的孔洞结构:一种为分子筛中没有被破坏的超笼,另一种为分子筛因骨架脱铝造成结构部分破坏而形成的孔洞.变温超极化129Xe NMR进一步表明,当稀土含量较低时,稀土离子能显著改善Y型分子筛的孔洞结构;稀土含量较高时,稀土离子不仅出现在分子筛超笼中,而且容易以氧化物形态在分子筛表面聚集,严重阻塞了Y型分子筛的孔洞.

The diffusion of C-4-C-24 alkanes, aromatics and cycloalkanes in FAU and MFI zeolites were studied systematically by molecular simulation. The basic data on diffusion energy barriers and the diffusion characteristics of alkanes, cycloalkanes and aromatics in FAU and MFI zeolites were obtained. It was found out that the 12-member-ring openings between the two adjacent super cages limited the diffusion of hydrocarbons in FAU zeolites, and the hydrocarbon molecules diffused more easily in the intersections of MFI zeolite channels than in the straight channels between the intersections. It was more difficult for the molecules to diffuse in the sinusoidal channel of the MFI zeolite than in the straight channel because of the atoms at the corner of sinusoidal channel. The diffusion of three kinds of C-6 alkanes was studied by gravity sorption method. The simulation results were well consistent with the experimental results, indicating that the simulation results were convincing.

通过乙基环己烷（ECH）在ZSM-5,MOR,EU-1分子筛上的反应,考察三种分子筛上的催化反应性能。采用X射线衍射（XRD）、N2-吸附（BET）、NH3-TPD、Py-IR吸附及热重方法表征分子筛的结构和酸性。结果表明:在ECH反应的复杂网络中,分子筛的孔道结构会对反应产物分布有重要影响;ECH异构化反应需要大量中强酸中心和较大的反应空间,具有十二元环孔道的MOR分子筛和具有十二元环侧笼的EU-1分子筛有较好的异构化反应性能。综合比较,三种分子筛中,EU-1分子筛上的ECH转化率和C8异构选择性较高。

Based on the detailed analysis in the complex deep catalytic catalyst(DCC) reaction network,the development of oil refining at the molecular level and the optimized catalysis kinetics(OCK in brief),an innovative catalyst technology had been developed for enhancing the heavy oil deep-cracking ability and optimizing the availability of the active sites.With such a technology,DMMC-1 of a new catalyst generation had been designed and developed for the DCC process.Comparing with the best catalyst used in industry now,DMMC-1 had the features of macropore structure,higher surface area and higher activity.The laboratory evaluation test results showed that with DMMC-1 the propylene yield increased by 2.25 percent and the propylene selectivity increased by 13.8%.The catalyst of DMMC-1 had improved its ability for heavy oil cracking and coke selectivity along with reduction of olefin content in gasoline to achieve a better product distribution and improve the product quality.