查看更多>>摘要：In this study,to meet the stringent requirements on the hydrophobicity of nano-SiO2 particles for use in depressurization and enhanced injection operations in high-temperature and high-salinity oil reservoirs,secondary chemical grafting modification of nano-SiO2 is performed using a silane coupling agent to prepare superhydrophobic nano-SiO2 particles.Using these superhydrophobic nano-SiO2 particles as the core agent,and liquid paraffin or diesel as the dispersion medium,a uniform dispersion of nano-SiO2 particles is achieved under high-speed stirring,and a chemically enhanced water injection system with colloidal stability that can be maintained for more than 60 d is successfully developed.Using this system,a field test of depressurization and enhanced injection is carried out on six wells in an oilfield,and the daily oil production level is increased by 11 t.The cumulative increased water injection is 58784 m3,the effective rate of the measures was 100%,and the average validity period is 661 d.
查看更多>>摘要：A series of Ni/ZSM-5 containing a small amount of Ni was prepared by an ion exchanged method.The impact of the n(SiO2)/n(Al2O3)ratio on the catalytic activity was studied using the samples 0.09Ni/ZSM-5(60)and 0.09Ni/ZSM-5(130).To determine the interaction between the Ni species and acid sites on the surface of the catalyst,the catalysts were characterized by N2 adsorption-desorption,X-ray diffraction(XRD),scanning electron microscopy(SEM),and UV-vis spectroscopy.The performance of the catalysts for the catalytic oligomerization of 1-hexene was investigated in detail.The nickel species were found to be uniformly distributed in all the catalysts.It was discovered that the oligomerization activity of the catalyst can be improved using Ni species;however,the contribution of Brønsted acids in oligomerization reactions is greater than that of Ni sites and Lewis acids.
查看更多>>摘要：A total of 14 halophilic hydrocarbon-degrading strains were isolated from crude oil-contaminated sites,using petroleum as the sole carbon and energy source.Among these,four highly efficient strains were selected to create the mixed bacterial agent XH-1.These four strains were identified through 16S rRNA gene-based sequencing as belonging to Acinetobacter,Bacillus paramycoides,Rhodococcus sp.,and Enterobacter sp.,respectively.The optimal cultivation time for the mixed consortium XH-1 was found to be 48 h,and a nitrogen-phosphorus molar ratio of 10:1 was determined to be beneficial for crude oil degradation.XH-1 showed notable crude oil degradation even at a salinity of up to 30 g/L,with little inhibition observed at sulfide concentrations as high as 150 mg/L and initial oil concentrations of 500 mg/L.Gas chromatography analysis revealed that XH-1 was able to efficiently degrade C9-C29 n-alkanes.Moreover,a bio-contact oxidation reactor enhanced by XH-1 showed promising results in treating oilfield wastewater.These findings suggest that XH-1 can be applied for the treatment of oilfield wastewater.
查看更多>>摘要：Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO3(MeO=Fe2O3,NiO or Co2O3)composite metal oxides were prepared via citrate gel and impregnation methods,and used as oxygen carriers for CL-ODH.X-ray diffraction results indicated that all oxygen carriers had a perovskite structure even after eight redox cycles.Under a reaction temperature of 650 ℃,a reaction pressure of 0.1 MPa,and a weight hourly space velocity(WHSV)of 7500 mL/(g·h),ethane conversion over Co2O3/LaCoO3 reached 100％and ethylene selectivity reached 60％,both of which were better than corresponding values attained over Fe2O3/LaCoO3 and NiO/LaCoO3.Ethylene selectivity remained stable for 80 cycles over Co2O3/LaCoO3,then decreased gradually after 80 cycles.X-ray photoelectron spectroscopy results and evaluation results indicated that lattice oxygen and O22-had a direct relationship with ethane conversion and ethylene selectivity.Co2O3/LaCoO3 exhibited a strong capacity to release and absorb oxygen,mainly due to interaction between Co2O3 and LaCoO3.
查看更多>>摘要：The selective removal of trace acetylene in ethylene feed gas is of great significance in the petrochemical industry;however,there are still challenges in designing and developing high-performance catalysts.Here,a MOF-assisted encapsulation strategy was adopted for the precise synthesis of diatomic Pd2 sites on a ZnO support.When used for the acetylene semi-hydrogenation reaction,the dual-atom Pd2-ZnO catalyst exhibited improved catalytic performance,achieving complete conversion of acetylene at 125℃ with an 89％selectivity to ethene,as compared to Pd single-atom and nanoparticles.This enhancement was mainly attributed to the catalyst's ability to dissociate H2 and facilitate the desorption of intermediate C2H4.Moreover,the strong interaction between the support and the diatomic Pd sites was responsible for the catalyst's excellent stability during the long-term reaction.
查看更多>>摘要：Chemical looping oxidative dehydrogenation(CL-ODH)is an economically promising method for converting ethane into higher value-added ethylene utilizing lattice oxygen in redox catalysts,also known as oxygen carriers.In this study,perovskite-type oxide SrCoO3-δ and B-site Mn ion-doped oxygen carriers(SrCo1-xMnxO3-δ,x=0.1,0.2,0.3)were prepared and tested for the CL-ODH of ethane.The oxygen-deficient perovskite SrCoO3-δ exhibited high ethylene selectivity of up to 96.7％due to its unique oxygen vacancies and lattice oxygen migration rates.However,its low ethylene yield limits its application in the CL-ODH of ethane.Mn doping promoted the reducibility of SrCoO3-δ oxygen carriers,thereby improving ethane conversion and ethylene yield,as demonstrated by characterization and evaluation experiments.X-ray diffraction results confirmed the doping of Mn into the lattice of SrCoO3-δ,while X-ray photoelectron spectroscopy(XPS)indicated an increase in lattice oxygen ratio upon incorporation of Mn into the SrCoO3-δ lattice.Additionally,H2 temperature-programmed reduction(H2-TPR)tests revealed more peaks at lower temperature reduction zones and a decline in peak positions at higher temperatures.Among the four tested oxygen carriers,SrCo0.8Mn0.2O3-δ exhibited satisfactory performance with an ethylene yield of 50％at 710℃ and good stability over 20 redox cycles.The synergistic effect of Mn plays a key role in increasing ethylene yields of SrCoO3-δ oxygen carriers.Accordingly,SrCo0.8Mn0.2O3-δ shows promising potential for the efficient production of ethylene from ethane via CL-ODH.
查看更多>>摘要：Hydroisomerization of n-heptane is an efficient method for producing gasoline with a high octane number.The focus of this study was to find a highly efficient catalyst that could both promote the conversion of n-heptane and inhibit the cracking side reaction.MIL-101(Cr)is a chromium-based metal-organic framework(MOF)with good hydrothermal stability,and exhibits a three-dimensional pore structure that is similar to that of zeolites.Using phosphomolybdic acid(PMA;H3PMo12O40·xH2O)can increase the number of Brønsted acid sites on MIL-101(Cr),which contributes to improving the catalytic performance during isomerization.In this study,0.4％Pt/PMA-MIL-101(Cr)catalyst was successfully crystallized at 220℃ using a hydrothermal synthetic method.The results showed that the synthesized samples were mesoporous-microporous composite materials with the typical octahedral structure,and the MIL-101(Cr)framework was not damaged following modification with PMA.It was found that 0.4％Pt30％ PMA-MIL-101(Cr)exhibited the best performance for isomerization of n-heptane,with a conversion rate and selectivity at 260℃ of 47.6％and 96.6％,respectively.After five hours of reaction,the conversion rate and selectivity of the catalyst remained above 38％and 80％,respectively.
查看更多>>摘要：Steam pretreatment is a widely used method for modifying the acidity and structure of zeolites,thereby enhancing their catalytic properties.This study systematically investigated the effects of steam treatment on ZSM-5 zeolites at varying treatment temperatures and durations.The structural evolution of the catalysts was monitored using N2 adsorption-desorption,X-ray diffraction,inductively coupled plasma optical emission spectroscopy,scanning electron microscopy,NH3 temperature-programmed desorption,in situ pyridine infrared spectroscopy,and thermogravimetric analysis.The characterization results revealed that mesopores were introduced into the ZSM-5 zeolite catalysts through dealumination induced using steam treatment at moderate temperatures(400 and 500℃).Moreover,compared with the parent catalyst,the steam-treated catalysts exhibited a lower amount of acid sites and relative crystallinity,while the n(Si)/n(Al)ratio increased.In the co-conversion of methanol and n-hexane in a fixed bed reactor at 400℃and 0.5 MPa(N2 atmosphere),with a weight hourly space velocity of 1 h-1 and a stoichiometric ratio of 1:1(CH3OH to n-hexane),the steam-treated catalysts displayed a prolonged catalyst lifetime.Particularly,the parent zeolite had a lifetime of 96 h,while the catalyst treated at 500℃for 12 h had a lifetime of up to 240 h.Additionally,the steam-treated catalysts maintained stable n-hexane conversion and improved aromatic selectivity.Notably,these treated catalysts exhibited a lower deactivation rate than the parent catalyst,and would be conducive to industrial scale-up production.
查看更多>>摘要：Tungstated zirconia(WO3/ZrO2)solid acid catalysts with different WO3 contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO3/ZrO2 solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO3 content of the WO3/ZrO2 catalysts had an important impact on the structure and property of the catalysts.When the WO3 mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO3 was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO3/ZrO2 solid acid catalysts.
查看更多>>摘要：1-Butyl-3-methylimidazolium bromide-based([Bmim]Br-based)deep eutectic solvents(DESs)can be used as effective extractants for removing nitrogen compounds from fuel oil.Among the DESs studied,the combination of[Bmim]Br and malonic acid(MA)in a 1:1 molar ratio demonstrated good performance for the removal of both basic and non-basic N compounds.The DES[Bmim]Br-MA exhibited extraction efficiencies of 98.4%for quinoline and 92.9%for indole after 30 min at 30℃with a DES/oil mass ratio of 1/7.Moreover,the extraction efficiencies remained high at 86.4%for quinoline and 85.9%for indole after recycling the DES four times..In addition,the DES[Bmim]Br-MA could effectively remove N compounds from Fushun shale diesel oil,with extraction efficiencies of 83.5%for total nitrogen and 89.9%for basic nitrogen at a DES/oil mass ratio of 1/1.
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