A few-layered hexagonal boron nitride nanosheets stabilized platinum nanoparticles(Pt/h-BNNS)is engineered for oxidation-promoted adsorptive desulfurization(OPADS)of fuel oil.It was found that the few-layered structur...A few-layered hexagonal boron nitride nanosheets stabilized platinum nanoparticles(Pt/h-BNNS)is engineered for oxidation-promoted adsorptive desulfurization(OPADS)of fuel oil.It was found that the few-layered structure and the defective sites of h-BNNS not only are beneficial to the stabilization of Pt NPs but also favor the adsorption of aromatic sulfides.By employing Pt/h-BNNS with a Pt loading amount of 1.19 wt%as the active adsorbent and air as an oxidant,a 98.0%sulfur removal over dibenzothiophene(DBT)is achieved along with a total conversion of the DBT to the corresponding sulfones(DBTO_(2)).Detailed experiments show that the excellent desulfurization activity originates from the few-layered structure of h-BNNS and the high catalytic activity of Pt NPs.In addition,the OPADS system with Pt/h-BNNS as the active adsorbent shows remarkable stability in desulfurization performance with the existence of different interferents such as olefin,and aromatic hydrocarbons.Besides,the Pt/h-BNNS can be recycled 12 times without a significant decrease in desulfurization performance.Also,a process flow diagram is proposed for deep desulfurization of fuel oil and recovery of high value-added products,which would promote the industrial application of such OPADS strategy.展开更多
Steam flooding is a widely used technique to enhance oil recovery of heavy oil.Thermal viscosity reduction and distillation effect are considered as two main displacement mechanisms in steam flooding process.However,t...Steam flooding is a widely used technique to enhance oil recovery of heavy oil.Thermal viscosity reduction and distillation effect are considered as two main displacement mechanisms in steam flooding process.However,the molecular composition understanding and contribution for oil production are still unclear.In this study,the composition analysis of the heavy oil was investigated in the core scale steam flooding process with the temperature from 120 to 280℃.The crude oil,produced oils and residual oils were characterized comprehensively by gas chromatography and high-resolution mass spectrometry.It is found that steam flooding preferentially extracts aromatics and remains more resins in the residual oil.Viscosity reduction is the dominant mechanism when steam is injected at a low temperature.Large molecular heteroatoms with high carbon number and high double bond equivalent(DBE)are eluted into the produced oil,while compounds with low carbon number and low DBE are remained in the residual oil.As the steam temperature rises,the increased distillation effect results in the extraction of light hydrocarbons from the residual oil to the produced oil.More small heteroatoms with low carbon number and low DBE enter into the produced oil,especially in the none water cut stage.The compositional difference of produced oils is characterized in DBE versus carbon number distribution of the N and O containing compound classes.This work uses a variety of composition analysis methods to clarify the steam flooding mechanism and provides a novel understanding of steam flooding mechanisms with various temperatures and production stages from the molecular perspective.展开更多
Low-temperature oxidation(LTO)is the main reaction that affects fuel formation in the in-situ combustion process,which has important significance for the subsequent combustion propulsion and the successful extraction ...Low-temperature oxidation(LTO)is the main reaction that affects fuel formation in the in-situ combustion process,which has important significance for the subsequent combustion propulsion and the successful extraction of crude oil.In this study,heavy oil was subjected to LTO reactions at different temperatures.Three types of reaction products with varying oxidation depths were characterized in terms of the number of oxygen atoms and the polarity of the molecule to reveal the low-temperature oxidation process of the heavy oil.Ketone compounds and acid polyoxides in the oil phase and deep oxidation products with a higher number of oxygen atoms in the coke were identified with increasing oxidation depth.The experimental results showed that the oxidation reaction of the heavy oil changed from kinetic-controlled to diffusion-controlled in the open oxidation system of the heavy oil as the oxidation depth increased.The oxidation reaction of the oil phase reached a maximum and stable value in oxygen content.The molecular compositions of the ketone compound and acid polyoxide did not change significantly with further increase in reaction temperature.The molecular compositions of the deep oxidation products with a higher number of oxygen atoms in the coke phase changed significantly.The coke precursor molecules with a lower oxygen content and condensation degree participated in the coke formation,and the oxidation reaction pathway and the complexity of the oxidation product component also increased.展开更多
Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the ...Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the oil viscosity. However, the relationship between the molecular composition of naphthenic acids and oil viscosity is not well understood. This study examined a “clean” heavy oil with low contents of heteroatoms but had a high content of naphthenic acids. Naphthenic acids were fractionated by distillation and caustic extraction. The molecular composition was characterized by high-resolution Orbitrap mass spectrometry. It was found that the 2- and 3-ring naphthenic monoacids with 15–35 carbon atoms are dominant components of the acid fractions;the caustic extraction is capable of isolating naphthenic acids with less than 35 carbons, which is equivalent to the upper limit of the distillable components, but not those in the residue fraction;the total acid number of the heavy distillates is higher than that of the residue fraction;the viscosity of the distillation fraction increases exponentially with an increased boiling point of the distillates. Blending experiments indicates that there is a strong correlation between the oil viscosity and acids content, although the acid content is only a few percent of the total oil.展开更多
Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products.Among the different properties of lubricating oils,density a...Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products.Among the different properties of lubricating oils,density and refractive index are some of the most important properties which can both be used for petroleum fluid characterization.Predictions of density and refractive index for naphthenic oils during solvent extraction by DMSO obtained by the pseudo-component approach and the quadratic correlation were both examined.The pseudo-component approach is a method to predict density and refractive index from composition while the latter merely relates density to refractive index.Results indicated that the predictions yielded by the pseudo-component method were in good agreement with experimental data for naphthenic oils.And the use of a function of refractive index(FRI_(20))as a pseudo-component property remarkably improved n_(20)predictions for the naphthenic mixtures.However,the density and refractive index predictions obtained by the quadratic correlation exhibited significantly higher de-viations for naphthenic oils than those for paraffinic oils.Thus a new modified correlation of the same functional form was proposed for naphthenic oils.The modification significantly improved predictions for naphthenic oils,which presented similar accuracy as the pseudo-component approach.And the previous correlation was still used for paraffinic oils.Additionally,effect of temperature on density and refractive index of naphthenic oils was examined.Results showed that the modified quadratic correlation was accurate for describing the relationship between density and refractive index of naphthenic oils at 20-90℃.The temperature dependence of density and refractive index for the raffinates and the extracts could be accurately described by the thermal coefficients for saturates and aromatics,respectively.Regarding the refractive index variation of the extracts with temperature,the empirical equation was proved to be a better option compared with the method using the thermal coefficient for aromatics.展开更多
In order to develop the conversion of heavy oil with a high yield of propylene in the catalytic cracking process, ZSM-5 zeolite was modified by tungsten and phosphorus, which was proved to be an effective method. Char...In order to develop the conversion of heavy oil with a high yield of propylene in the catalytic cracking process, ZSM-5 zeolite was modified by tungsten and phosphorus, which was proved to be an effective method. Characterization results show that the improvement of catalytic performance could be correlated to the interaction of phosphorus and tungsten species on ZSM-5. P inhibited the aggregation of tungsten species on ZSM-5 and was conductive to convert the tungsten species with octahedral coordination into tetrahedral coordination. And this ultimately led to that more acid sites were reserved after hydrothermal treatment in the tungsten and phosphorus co-modified ZSM-5 catalyst.Phosphorus species played an important role to restrain the dehydrogenation activity of tungsten. In addition, a model reflecting the interaction between tungsten species and ZSM-5 framework was proposed.展开更多
This paper investigated the secondary cracking of gasoline and diesel from the catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 in a fluidized bed reactor.The results show that the secondary crackin...This paper investigated the secondary cracking of gasoline and diesel from the catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 in a fluidized bed reactor.The results show that the secondary cracking reactivity of gasoline and diesel is poor,and the yield of total light olefins is only about 10%(by mass).As reaction temperature increases,ethylene yield increases,butylene yield decreases,and propylene yield shows a maximum.The optimal reaction temperature is about 670℃for the production of light olefins.With the enhance- ment of catalyst-to-oil mass ratio and steam-to-oil mass ratio,the yields of light olefins increase to some extent. About 6.30%of the mass of total aromatic rings is converted by secondary cracking,indicating that aromatic hy- drocarbons are not easy to undergo ring-opening reactions under the present experimental conditions.展开更多
Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in...Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in light of itshigher selectivity, to obtain extracts with a high aromatic content for naphthenic lubricating base oils. We systematicallyinvestigated effects of the solvent-to-oil (S/O) ratio and extraction temperature on the yield of the extract, efficiency ofaromatic removal, and composition of the extracts and raffinates. The results showed that the aromatic content of extractsfor naphthenic oils could reach a high value of about 80%. The solvent maintained a high selectivity for aromatics fornaphthenic oils even under a high S/O ratio and a high extraction temperature. Moreover, the efficiency of aromatic removalfor naphthenic lubricating base oils could be enhanced by increasing either the S/O ratio or the extraction temperature,although these measures had limited effects in practice. Following this, we used the non-random two-liquid (NRTL) modelbased on the pseudo-component approach to simulate the liquid-liquid equilibrium of the system of DMSO + naphtheniclubricating base oils, and determined the parameters of binary interaction through regression based on the data on phaseequilibrium. The modeling results showed that the predicted yield, content of the solvent, and composition of the raffinatesand extracts were in good agreement with those obtained in the experiments. This validates the reliability of the model usedto represent the DMSO + naphthenic lubricating base oil system. Both the experimental data and the method of simulationreported here can help optimize the extraction of naphthenic lubricating base oils, and provide a better understanding of thecorresponding process.展开更多
As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsifica...As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.展开更多
Toluene insoluble matter (TIM) in coker heavy gas oil (CHGO) from oil sands bitumen is harmful to the downstream hydrotreating, and it may be difficult to be removed by conventional filtration. In order to determine i...Toluene insoluble matter (TIM) in coker heavy gas oil (CHGO) from oil sands bitumen is harmful to the downstream hydrotreating, and it may be difficult to be removed by conventional filtration. In order to determine its origin, the TIM must first be separated from CHGO for characterization. Two techniques are described to acomplish this goal. In the ultra-centrifugation approach used in this work, CHGO is blended with a miscible liquid and centrifuged under 366000 G (gravity) force. Through this procedure toluene and hexane diluents yielded TIM contents of 24μg.g^-1 and 88μg.g^-1 respectively. In an alternative simplified procedure, the initial ultracentrifugation step is omitted. Several different solvents are evaluated for use as diluents but, in each case, toluene is still used in the subsequent washing steps. TIM contents determined by this method range from 23 to about 200μg.g^-1. The amount of TIM separated by means of this method depends primarily on the initial diluent used.Other conditions, such as diluent-oil ratio, water-oil ratio, mixing time, temperature and water pH value, are also studied.展开更多
There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery(IMEOR) processes.In the present study,the potential of rice bran as a carbon s...There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery(IMEOR) processes.In the present study,the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale.The co-applications of rice bran,K_2HPO_4 and urea under optimized bio-stimulation conditions significantly increased the production of gases,acids and emulsifiers.The structure and diversity of microbial community greatly changed during the IMEOR process,in which Clostridium sp.,Acidobacteria sp.,Bacillus sp.,and Pseudomonas sp.were dominant.Pressurization,acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes.This study indicated that rice bran is a potential carbon source for IMEOR.展开更多
The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of...The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of asphaltene molecules were estimated by combining 1 H nuclear magnetic resonance and X-ray diffraction analyses,and were also ob-tained from vapor pressure osmometry and elemental analysis.Heteroatoms,such as S,N,and O atoms,were considered in the construction of average molecular structure of heavy oils.Two important structural parameters were proposed,including the number of alkyl chain substituents to aromatic rings and the number of total rings with heteroatoms.Ultimately,the av-erage molecular structures of polycyclic aromatics,heavy resins and asphaltene molecules were constructed.The number of α-,β-,γ-,and aromatic hydrogen atoms of the constructed average molecular structures fits well with the number of hydro-gen atoms derived from the experimental spectral data.展开更多
The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable f...The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable for selective hydrocracking of straight run diesel oil to produce high-quality ethylene cracking feedstock at low cost was developed, by optimizing the composition of catalyst support materials, using amorphous silicon aluminum and aluminum oxide with high mesopore content as the main support, and modified Y zeolite with excellent aromatic ring opening selectivity as the acidic component. The catalyst has in-depth characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N<sub>2</sub>-low temperature adsorption-desorption, NH<sub>3</sub>-temperature-programmed desorption, and IR techniques. And its catalytic cracking straight run diesel oil performance was evaluated. The results show that the prepared catalyst has high polycyclic aromatic hydrocarbon ring opening cracking selectivity. However, alkanes retained in diesel distillates can achieve the goal of producing more ethylene cracking feedstocks with low BMCI value under low and moderate pressure conditions. This work may shed significant technical insight for oil refining transformation.展开更多
It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(...It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(A_(2)B_(2)O_(7)-type)catalysts with disordered defective cubic fluorite phased structure were successfully prepared by a colloidal crystal template method.3DOM structure promotes the accessibility of the gaseous reactants(O2and CH4)to the active sites.The co-doping of Ca and Sr ions in La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts improved the formation of oxygen vacancies,thereby leading to increased density of surface-active oxygen species(O_(2)^(-))for the activation of CH4and the formation of C2products(C2H6and C2H4).3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts exhibit high catalytic activity for OCM at low temperature.3DOM La1.7Sr0.3Ce1.7Ca0.3O7-δcatalyst with the highest density of O_(2)^(-)species exhibited the highest catalytic activity for low-temperature OCM,i.e.,its CH4conversion,selectivity and yield of C2products at 650℃are 32.2%,66.1%and 21.3%,respectively.The mechanism was proposed that the increase in surface oxygen vacancies induced by the co-doping of Ca and Sr ions boosts the key step of C-H bond breaking and C-C bond coupling in catalyzing low-temperature OCM.It is meaningful for the development of the low-temperature and high-efficient catalysts for OCM reaction in practical application.展开更多
An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and ...An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and 9.3%,respectively.Through ANN model,the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed.Droplet size gradually increases with the increase of interfacial tension,and decreases with the increase of pulse intensity.It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range.For two kinds of columns,the drop size prediction deviations of ANN model are 9.6%and 18.5%and the deviations in correlations are 11%and 15%.展开更多
Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective method.Al-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proporti...Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective method.Al-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proportion)were prepared and dibenzothiophene(DBT)and 4,6-dimethyl-dibenzothiophene(4,6-DMDBT)were employed as the probes to evaluate the hydrodesulfurization(HDS)catalytic performance.The as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS performance.The average pore sizes of series AYP-x supports are above 6.0 nm,which favors the mass transfer of organic sulfides.The cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active metals.Aluminum embedded into the silica framework could facilitate the formation of Lewis(L)and Brønsted(B)acid sites and adjust the metal-support interaction(MSI).Among all the as-synthesized catalysts,NiMo/AYP-20 catalyst shows the highest HDS activities.The improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica,enhanced acidity,moderate MSI,and good accessibility/dispersion of active components.展开更多
Light plays an important role in the photosynthesis and metabolic process of microalgae.However,how different light conditions regulate the biomass production and protein accumulation of microalgae is mostly unknown.I...Light plays an important role in the photosynthesis and metabolic process of microalgae.However,how different light conditions regulate the biomass production and protein accumulation of microalgae is mostly unknown.In this study,the influence of different light conditions,including light colors,densities,and light:dark cycles on the cell growth and biochemical composition of Spirulina platensis was symmetrically characterized.Under different colored lights,S.platensis all shows an increase trend within the increased light intensity ranges;however,each showing different optimal light intensities.At the same light intensity,different colored lights show different growth rate of S.platensis following the sequence of red>white>green>yellow>blue.The maximum growth rate and protein accumulation were determined as 21.88 and 5.10 mg/(L·d)when illuminated under red LED.The energy efficiency of different light sources was calculated and ranked as red>white>blue≈green>yellow.Transcriptomic analysis suggests that red light can promote cell growth and protein accumulation by upregulating genes related to photosynthesis,carbon fixation,and C-N metabolism pathways.This study provides a conducive and efficient way to promote biomass production and protein accumulation of S.platensis by regulating light conditions.展开更多
Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sit...Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.展开更多
基金financial support from the National Natural Science Foundation of China(22178154,22008094,21908082,21878133)Natural Science Foundation of Jiangsu Province(BK20190852,BK20190854)Natural Science Foundation for Jiangsu Colleges and Universities(19KJB530005).
文摘A few-layered hexagonal boron nitride nanosheets stabilized platinum nanoparticles(Pt/h-BNNS)is engineered for oxidation-promoted adsorptive desulfurization(OPADS)of fuel oil.It was found that the few-layered structure and the defective sites of h-BNNS not only are beneficial to the stabilization of Pt NPs but also favor the adsorption of aromatic sulfides.By employing Pt/h-BNNS with a Pt loading amount of 1.19 wt%as the active adsorbent and air as an oxidant,a 98.0%sulfur removal over dibenzothiophene(DBT)is achieved along with a total conversion of the DBT to the corresponding sulfones(DBTO_(2)).Detailed experiments show that the excellent desulfurization activity originates from the few-layered structure of h-BNNS and the high catalytic activity of Pt NPs.In addition,the OPADS system with Pt/h-BNNS as the active adsorbent shows remarkable stability in desulfurization performance with the existence of different interferents such as olefin,and aromatic hydrocarbons.Besides,the Pt/h-BNNS can be recycled 12 times without a significant decrease in desulfurization performance.Also,a process flow diagram is proposed for deep desulfurization of fuel oil and recovery of high value-added products,which would promote the industrial application of such OPADS strategy.
文摘Steam flooding is a widely used technique to enhance oil recovery of heavy oil.Thermal viscosity reduction and distillation effect are considered as two main displacement mechanisms in steam flooding process.However,the molecular composition understanding and contribution for oil production are still unclear.In this study,the composition analysis of the heavy oil was investigated in the core scale steam flooding process with the temperature from 120 to 280℃.The crude oil,produced oils and residual oils were characterized comprehensively by gas chromatography and high-resolution mass spectrometry.It is found that steam flooding preferentially extracts aromatics and remains more resins in the residual oil.Viscosity reduction is the dominant mechanism when steam is injected at a low temperature.Large molecular heteroatoms with high carbon number and high double bond equivalent(DBE)are eluted into the produced oil,while compounds with low carbon number and low DBE are remained in the residual oil.As the steam temperature rises,the increased distillation effect results in the extraction of light hydrocarbons from the residual oil to the produced oil.More small heteroatoms with low carbon number and low DBE enter into the produced oil,especially in the none water cut stage.The compositional difference of produced oils is characterized in DBE versus carbon number distribution of the N and O containing compound classes.This work uses a variety of composition analysis methods to clarify the steam flooding mechanism and provides a novel understanding of steam flooding mechanisms with various temperatures and production stages from the molecular perspective.
基金supported by the National Key R&D Program of China(2018YFA0702400)the PetroChina Exploration&Production Company(KS2020-01-05).
文摘Low-temperature oxidation(LTO)is the main reaction that affects fuel formation in the in-situ combustion process,which has important significance for the subsequent combustion propulsion and the successful extraction of crude oil.In this study,heavy oil was subjected to LTO reactions at different temperatures.Three types of reaction products with varying oxidation depths were characterized in terms of the number of oxygen atoms and the polarity of the molecule to reveal the low-temperature oxidation process of the heavy oil.Ketone compounds and acid polyoxides in the oil phase and deep oxidation products with a higher number of oxygen atoms in the coke were identified with increasing oxidation depth.The experimental results showed that the oxidation reaction of the heavy oil changed from kinetic-controlled to diffusion-controlled in the open oxidation system of the heavy oil as the oxidation depth increased.The oxidation reaction of the oil phase reached a maximum and stable value in oxygen content.The molecular compositions of the ketone compound and acid polyoxide did not change significantly with further increase in reaction temperature.The molecular compositions of the deep oxidation products with a higher number of oxygen atoms in the coke phase changed significantly.The coke precursor molecules with a lower oxygen content and condensation degree participated in the coke formation,and the oxidation reaction pathway and the complexity of the oxidation product component also increased.
基金supported by the National Key R&D Program of China(2018YFA0702400)Science Foundation of China University of Petroleum,Beijing(ZX20210029).
文摘Most heavy crude oils underwent biodegradation and generated a significant amount of naphthenic acids. Naphthenic acids are polar compounds with the carboxylic group and are considered as a major factor affecting the oil viscosity. However, the relationship between the molecular composition of naphthenic acids and oil viscosity is not well understood. This study examined a “clean” heavy oil with low contents of heteroatoms but had a high content of naphthenic acids. Naphthenic acids were fractionated by distillation and caustic extraction. The molecular composition was characterized by high-resolution Orbitrap mass spectrometry. It was found that the 2- and 3-ring naphthenic monoacids with 15–35 carbon atoms are dominant components of the acid fractions;the caustic extraction is capable of isolating naphthenic acids with less than 35 carbons, which is equivalent to the upper limit of the distillable components, but not those in the residue fraction;the total acid number of the heavy distillates is higher than that of the residue fraction;the viscosity of the distillation fraction increases exponentially with an increased boiling point of the distillates. Blending experiments indicates that there is a strong correlation between the oil viscosity and acids content, although the acid content is only a few percent of the total oil.
基金sponsored by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01F37).
文摘Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products.Among the different properties of lubricating oils,density and refractive index are some of the most important properties which can both be used for petroleum fluid characterization.Predictions of density and refractive index for naphthenic oils during solvent extraction by DMSO obtained by the pseudo-component approach and the quadratic correlation were both examined.The pseudo-component approach is a method to predict density and refractive index from composition while the latter merely relates density to refractive index.Results indicated that the predictions yielded by the pseudo-component method were in good agreement with experimental data for naphthenic oils.And the use of a function of refractive index(FRI_(20))as a pseudo-component property remarkably improved n_(20)predictions for the naphthenic mixtures.However,the density and refractive index predictions obtained by the quadratic correlation exhibited significantly higher de-viations for naphthenic oils than those for paraffinic oils.Thus a new modified correlation of the same functional form was proposed for naphthenic oils.The modification significantly improved predictions for naphthenic oils,which presented similar accuracy as the pseudo-component approach.And the previous correlation was still used for paraffinic oils.Additionally,effect of temperature on density and refractive index of naphthenic oils was examined.Results showed that the modified quadratic correlation was accurate for describing the relationship between density and refractive index of naphthenic oils at 20-90℃.The temperature dependence of density and refractive index for the raffinates and the extracts could be accurately described by the thermal coefficients for saturates and aromatics,respectively.Regarding the refractive index variation of the extracts with temperature,the empirical equation was proved to be a better option compared with the method using the thermal coefficient for aromatics.
文摘In order to develop the conversion of heavy oil with a high yield of propylene in the catalytic cracking process, ZSM-5 zeolite was modified by tungsten and phosphorus, which was proved to be an effective method. Characterization results show that the improvement of catalytic performance could be correlated to the interaction of phosphorus and tungsten species on ZSM-5. P inhibited the aggregation of tungsten species on ZSM-5 and was conductive to convert the tungsten species with octahedral coordination into tetrahedral coordination. And this ultimately led to that more acid sites were reserved after hydrothermal treatment in the tungsten and phosphorus co-modified ZSM-5 catalyst.Phosphorus species played an important role to restrain the dehydrogenation activity of tungsten. In addition, a model reflecting the interaction between tungsten species and ZSM-5 framework was proposed.
基金Supported by the Major Research Plan of Ministry of Education of China(No.307008).
文摘This paper investigated the secondary cracking of gasoline and diesel from the catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 in a fluidized bed reactor.The results show that the secondary cracking reactivity of gasoline and diesel is poor,and the yield of total light olefins is only about 10%(by mass).As reaction temperature increases,ethylene yield increases,butylene yield decreases,and propylene yield shows a maximum.The optimal reaction temperature is about 670℃for the production of light olefins.With the enhance- ment of catalyst-to-oil mass ratio and steam-to-oil mass ratio,the yields of light olefins increase to some extent. About 6.30%of the mass of total aromatic rings is converted by secondary cracking,indicating that aromatic hy- drocarbons are not easy to undergo ring-opening reactions under the present experimental conditions.
基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01F37).
文摘Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in light of itshigher selectivity, to obtain extracts with a high aromatic content for naphthenic lubricating base oils. We systematicallyinvestigated effects of the solvent-to-oil (S/O) ratio and extraction temperature on the yield of the extract, efficiency ofaromatic removal, and composition of the extracts and raffinates. The results showed that the aromatic content of extractsfor naphthenic oils could reach a high value of about 80%. The solvent maintained a high selectivity for aromatics fornaphthenic oils even under a high S/O ratio and a high extraction temperature. Moreover, the efficiency of aromatic removalfor naphthenic lubricating base oils could be enhanced by increasing either the S/O ratio or the extraction temperature,although these measures had limited effects in practice. Following this, we used the non-random two-liquid (NRTL) modelbased on the pseudo-component approach to simulate the liquid-liquid equilibrium of the system of DMSO + naphtheniclubricating base oils, and determined the parameters of binary interaction through regression based on the data on phaseequilibrium. The modeling results showed that the predicted yield, content of the solvent, and composition of the raffinatesand extracts were in good agreement with those obtained in the experiments. This validates the reliability of the model usedto represent the DMSO + naphthenic lubricating base oil system. Both the experimental data and the method of simulationreported here can help optimize the extraction of naphthenic lubricating base oils, and provide a better understanding of thecorresponding process.
基金Scientific Platform Project of the Ministry of Education(fykf201907)the Postdoctoral Science Foundation Project of the Natural Science Foundation of Chongqing Municipality(cstc2021jcyjbshX0194)+3 种基金Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100820 and KJZD-K201900804)Science and Technology Innovation Project of the Construction of the Chengdu-Chongqing Economic Circle of Chongqing Municipal Education Commission(KJCX2020036)Scientific Research Project of Chongqing Technology and Business University(2152016 and 2056006)Chongqing Technical Innovation and Application Project(cstc2019jscx-msxmX0275).
文摘As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.
基金CHGO sample was provided by Synrude Canada Ltd.Plant.
文摘Toluene insoluble matter (TIM) in coker heavy gas oil (CHGO) from oil sands bitumen is harmful to the downstream hydrotreating, and it may be difficult to be removed by conventional filtration. In order to determine its origin, the TIM must first be separated from CHGO for characterization. Two techniques are described to acomplish this goal. In the ultra-centrifugation approach used in this work, CHGO is blended with a miscible liquid and centrifuged under 366000 G (gravity) force. Through this procedure toluene and hexane diluents yielded TIM contents of 24μg.g^-1 and 88μg.g^-1 respectively. In an alternative simplified procedure, the initial ultracentrifugation step is omitted. Several different solvents are evaluated for use as diluents but, in each case, toluene is still used in the subsequent washing steps. TIM contents determined by this method range from 23 to about 200μg.g^-1. The amount of TIM separated by means of this method depends primarily on the initial diluent used.Other conditions, such as diluent-oil ratio, water-oil ratio, mixing time, temperature and water pH value, are also studied.
基金supported in part by the National Natural Science Foundation of China (Nos. 51209216 and 21306229)the Korean RDA Grant (No. PJ009472)
文摘There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery(IMEOR) processes.In the present study,the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale.The co-applications of rice bran,K_2HPO_4 and urea under optimized bio-stimulation conditions significantly increased the production of gases,acids and emulsifiers.The structure and diversity of microbial community greatly changed during the IMEOR process,in which Clostridium sp.,Acidobacteria sp.,Bacillus sp.,and Pseudomonas sp.were dominant.Pressurization,acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes.This study indicated that rice bran is a potential carbon source for IMEOR.
基金the funding of the National Basic Research Program of China (Grant No.2006CB202505)
文摘The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of asphaltene molecules were estimated by combining 1 H nuclear magnetic resonance and X-ray diffraction analyses,and were also ob-tained from vapor pressure osmometry and elemental analysis.Heteroatoms,such as S,N,and O atoms,were considered in the construction of average molecular structure of heavy oils.Two important structural parameters were proposed,including the number of alkyl chain substituents to aromatic rings and the number of total rings with heteroatoms.Ultimately,the av-erage molecular structures of polycyclic aromatics,heavy resins and asphaltene molecules were constructed.The number of α-,β-,γ-,and aromatic hydrogen atoms of the constructed average molecular structures fits well with the number of hydro-gen atoms derived from the experimental spectral data.
文摘The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable for selective hydrocracking of straight run diesel oil to produce high-quality ethylene cracking feedstock at low cost was developed, by optimizing the composition of catalyst support materials, using amorphous silicon aluminum and aluminum oxide with high mesopore content as the main support, and modified Y zeolite with excellent aromatic ring opening selectivity as the acidic component. The catalyst has in-depth characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N<sub>2</sub>-low temperature adsorption-desorption, NH<sub>3</sub>-temperature-programmed desorption, and IR techniques. And its catalytic cracking straight run diesel oil performance was evaluated. The results show that the prepared catalyst has high polycyclic aromatic hydrocarbon ring opening cracking selectivity. However, alkanes retained in diesel distillates can achieve the goal of producing more ethylene cracking feedstocks with low BMCI value under low and moderate pressure conditions. This work may shed significant technical insight for oil refining transformation.
基金supported by the National Key Research and Development Program of China(Nos.2022YFB3504100,2022YFB3506200)the National Natural Science Foundation of China(Nos.22208373,22376217)+1 种基金the Beijing Nova Program(No.20220484215)the Science Foundation of China University of Petroleum,Beijing(No.2462023YJRC030)。
文摘It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(A_(2)B_(2)O_(7)-type)catalysts with disordered defective cubic fluorite phased structure were successfully prepared by a colloidal crystal template method.3DOM structure promotes the accessibility of the gaseous reactants(O2and CH4)to the active sites.The co-doping of Ca and Sr ions in La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts improved the formation of oxygen vacancies,thereby leading to increased density of surface-active oxygen species(O_(2)^(-))for the activation of CH4and the formation of C2products(C2H6and C2H4).3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts exhibit high catalytic activity for OCM at low temperature.3DOM La1.7Sr0.3Ce1.7Ca0.3O7-δcatalyst with the highest density of O_(2)^(-)species exhibited the highest catalytic activity for low-temperature OCM,i.e.,its CH4conversion,selectivity and yield of C2products at 650℃are 32.2%,66.1%and 21.3%,respectively.The mechanism was proposed that the increase in surface oxygen vacancies induced by the co-doping of Ca and Sr ions boosts the key step of C-H bond breaking and C-C bond coupling in catalyzing low-temperature OCM.It is meaningful for the development of the low-temperature and high-efficient catalysts for OCM reaction in practical application.
基金the support of the National Natural Science Foundation of China(22278234,21776151)。
文摘An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and 9.3%,respectively.Through ANN model,the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed.Droplet size gradually increases with the increase of interfacial tension,and decreases with the increase of pulse intensity.It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range.For two kinds of columns,the drop size prediction deviations of ANN model are 9.6%and 18.5%and the deviations in correlations are 11%and 15%.
基金The authors acknowledge the financial supports from the National Science Foundation of China(U1908204,91845201,and 22002093)the funds that Central Government Guides Local Science and Technology Development(2022JH6/100100052)Scientific Research Project of Education Department of Liaoning Province(LQN202006).
文摘Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective method.Al-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proportion)were prepared and dibenzothiophene(DBT)and 4,6-dimethyl-dibenzothiophene(4,6-DMDBT)were employed as the probes to evaluate the hydrodesulfurization(HDS)catalytic performance.The as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS performance.The average pore sizes of series AYP-x supports are above 6.0 nm,which favors the mass transfer of organic sulfides.The cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active metals.Aluminum embedded into the silica framework could facilitate the formation of Lewis(L)and Brønsted(B)acid sites and adjust the metal-support interaction(MSI).Among all the as-synthesized catalysts,NiMo/AYP-20 catalyst shows the highest HDS activities.The improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica,enhanced acidity,moderate MSI,and good accessibility/dispersion of active components.
基金the National Natural Science Foundation of China(Nos.42061134020,32070380)the Natural Science Foundation of Shandong Province(No.ZR2019ZD17)。
文摘Light plays an important role in the photosynthesis and metabolic process of microalgae.However,how different light conditions regulate the biomass production and protein accumulation of microalgae is mostly unknown.In this study,the influence of different light conditions,including light colors,densities,and light:dark cycles on the cell growth and biochemical composition of Spirulina platensis was symmetrically characterized.Under different colored lights,S.platensis all shows an increase trend within the increased light intensity ranges;however,each showing different optimal light intensities.At the same light intensity,different colored lights show different growth rate of S.platensis following the sequence of red>white>green>yellow>blue.The maximum growth rate and protein accumulation were determined as 21.88 and 5.10 mg/(L·d)when illuminated under red LED.The energy efficiency of different light sources was calculated and ranked as red>white>blue≈green>yellow.Transcriptomic analysis suggests that red light can promote cell growth and protein accumulation by upregulating genes related to photosynthesis,carbon fixation,and C-N metabolism pathways.This study provides a conducive and efficient way to promote biomass production and protein accumulation of S.platensis by regulating light conditions.
基金supported by China National Natural Science Foundation(22008260,21908123)。
文摘Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.
