Table of Content

12 June 2020, Volume 51 Issue 6

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CORRELATION OF MOLECULAR STRUCTURE AND VISCOSITY INDEX OF BASE OIL

2020, 51(6):  1-5. 

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The structure-activity relationship between molecular structure and viscosity index of lubricating base oil was revealed comprehensively and accurately through the proposed molecular structure parameters measured by high resolution mass spectrometry and nuclear magnetic resonance. It was demonstrated that VI increased with increasing average carbon number of the alkyl chain structure and lowered with increase of polycyclic naphthene carbons and iso/normal ratio. The structure-activity relationship between viscosity index and structural characterization parameters provides solutions for the selection of raw materials, optimization of process conditions and cutting of distillation range for the production of high-viscosity index base oil.

STUDY OF USY MOLECULAR SIEVE MODIFIED BY AMMONIUM FLUORIDE AND ITS CATALYTIC DEOLEFIN PERFORMANCE

2020, 51(6):  6-12. 

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USY molecular sieves before and after ammonium fluoride modification were characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, 27Al solid nuclear magnetic resonance, and pyridine adsorption-infrared spectroscopy, and its performance of removing trace amount of olefins from mixed aromatics was investigated in a bench-scale continuous-flow fixed bed reactor. The results showed that the pore structure and acidity of the USY molecular sieve could be effectively adjusted by ammonium fluoride modification; the framework aluminum component was extracted and deposited in the pores, the micro pore volume was basically unchanged; the pore size decreased, but the mesoporous and large pore volumes increased. The Lewis acid content of modified molecular sieve was 3 times that of before modification, but the change of Bronsted acid content was small. It is proved that the F-modified USY sieve can greatly reduced catalyst deactivation and increase the conversion rate of olfines.

NUMERICAL SIMULATION ANALYSIS OF INFLUENCE OF DIFFERENT PARAMETERS ON FLOW CHARACTERISTICS OF SALT-CONTAINING WASTE WATER IN EVAPORATOR PIPE

2020, 51(6):  13-18. 

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Evaporation treatment is one of methods for treatment of salt-containing waste water in refineries. However, there is a problem that the heat transfer effect is not good due to the difference of flow conditions in the evaporation process. Taking the salt-bearing wastewater of falling film evaporation as the object, the effects of different parameters on heat and mass transfer in evaporating tubes were analyzed by numerical simulation. The results showed that the effect of different liquid inlet velocities on the heating effect of the evaporative tube was complicated. The increase of inlet velocity leads to the increase of axial velocity. Although the heating time of the liquid thus became shorter, the heating effect was better. The increase of film gap had a positive effect on the temperature distribution near the wall, but the gas-phase turbulence intensity was slightly lower within 13.5-18.0 mm away from the center of the pipe. The temperature drop when the film gap was 1.25 mm was larger than that when the film gap was 1.0 mm and 1.5 mm. The increase of salinity of salt-containing sewage had adverse effects on heat and mass transfer in the evaporator tube. Especially the increase of temperature drop near the wall leads the increase of internal turbulence intensity within the range of 0-19 mm from the center of the tube in the radial direction and the increase of velocity within the range of 4 mm from the wall near the wall of the tube.

ACTING LAW AND MOLECULAR DYNAMICS SIMULATION OF OIL-SOLUBLE IMIDAZOLINE CORROSION INHIBITOR HHS-08

2020, 51(6):  19-26. 

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The application of supercritical CO2 flooding technology brings huge safety risks to the storage，transportation in the downstream of the petroleum industry. The law of corrosion inhibition of HHS-08 oil-soluble corrosion inhibitor (HHS-08 corrosion inhibitor) in the environment of supercritical CO2 flooding oilfield water was studied. HHS-08 inhibitor with different concentration was added to the above oilfield water successively，and polarization curves and electrochemical impedance spectroscopy of the corrosion system were tested by CHI604E electrochemical workstation. The adsorption behavior and mechanism of HHS-08 corrosion inhibitor on the Fe（001） plane were investigated by Materials Studio 8.0. The results of macroscopic morphology，corrosion weight loss test，polarization curves and impedance spectroscopy showed that the inhibition rate increased with the increase of HHS-08 inhibitor dosage. The corrosion inhibition efficiency reached a value of more than 80% at the concentration of 80 mg/L，however，the inhibition efficiency increased little when the dosage was increased further. The results of molecular dynamics showed that the HHS-08 inhibitor molecule could stably adsorb the polar head group (imidazole ring) on the Fe (001) plane through its own torsion deformation, while the alkyl carbon chain deviated from the metal surface to form a hydrophobic film, thus achieving good corrosion inhibition.

CHANGES OF ASPHALTENE STABILITY DURING RESIDUE HYDROTREATING

2020, 51(6):  27-33. 

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The effects of polycyclic aromatic hydrocarbons on the removal of impurities and the inhibition of carbon accumulation on catalyst in the RICP technology were studied with an autoclave using Saudi Arab (light) atmospheric residue as raw material. A method based on Flory-Huggins activity coefficient model was established to investigate the stability of asphaltenes at 380 ℃ and 14.0 MPa. The parameter A/B ratio was calculated, where A represents the reactivity of active hydrogen for HDS, HDN, HDCCR, and B is the reactivity of active hydrogen for asphaltene hydrogenation. It shows the tendency of reactive hydrogen to focus on the reaction: larger A means the higher the efficiency of active hydrogen in removing impurities; while the smaller B is the more efficient active hydrogen in the hydrogenation of asphaltenes. The results showed that after hydrotreating, the solubility difference between asphaltene and residual oil (containing dissolved hydrogen) increased, and the stability of asphaltene became worse. When the catalysts RDM-32, RDM-53 and RCS-31 were graded at a ratio of 40:10:50, the value of A/B for Saudi Arab (light) residue reached the maximum at 380 ℃ and 14.0 MPa. It indicated that the introduction of high aromatic fraction is beneficial to further increase the value of A/B. The reason why PAHs improve the impurity removal and inhibit catalyst carbon accumulation is that PAHs optimize the efficiency of active hydrogen for impurity removal and asphaltene hydrogenation.

RESEARCH ON STRUCTURE AND PERFORMANCE OF HIGH STABILIZED ZEOLITES MANUFACTURED BY THE NEW GAS-PHASE SUPER STABLE METHOD

2020, 51(6):  34-41. 

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In order to improve the stability and activity of zeolites，the active component of FCC catalyst, five kinds of high stabilized zeolites HSZ-1，HSZ-2，HSZ-3，HSZ-4，HSZ-5 with different cell sizes were designed and manufactured by changing the degree of cation exchange and gas phase super stable modification of zeolites. The structure and performance of the five kinds of high stabilized zeolites were analyzed by X-ray diffraction（XRD）, N2 adsorption desorption（BET） and Fourier transform infrared spectroscopy（FT-IR）techniques. The results showed that the developed high stabilized zeolites possessed the properties of high crystallinity，large specific surface area，high thermal stability and hydrothermal stability. Moreover, with the increase of the degree of super stable modification of zeolites, the cell constant of zeolites decreased, the content of SiO2 increased, the total acid quantity and the ratio of B/L ratio decreased, the amount of small cage hydroxyl decreased, the amount of terminal silicon hydroxyl increased, however the large cage hydroxyl group of the zeolites were all well preserved. In addition, HSZ series zeolites all contained four-coordinative framework aluminum and six-coordinative extra-framework aluminum species. The increase of the degree of super stable modification increased the content of extra-framework aluminum species; in addition to the four kinds of Si coordination states, HSZ-1 zeolite with the highest hyperstability also contains Si fragments.

PREPARATION AND PERFORMANCE EVALUATION OF ANTI-IRON CONTAMINATION FCC CATALYST

2020, 51(6):  42-46. 

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Pseudo-boehmite modified kaolinite was synthesized by in situ construction, and used as matrix material for preparation of anti-iron contamination FCC catalyst. Characterization results indicated that, compared with ordinary kaolinite, the synthesized compound material had much higher surface area, pore volume and surface acidity density, up to 112 m2/g, 0.39 cm3/g and 78.3μmol/g，respectively. Catalytic cracking performance evaluation results indicated that the conversion of the modified kaolinite increased by 1.96 percentage points, slurry yield decreased by 1.22 percentage points, gasoline yield and total liquid increased by 2.08 and 2.23 percentage points, respectively, compared with the traditional FCC catalyst at the same iron pollution, indicating a good anti-iron contamination performance.

MICROWAVE-ASSISTED SYNTHESIS OF SILVER-MAGNESIUM CO-DOPED ZINC OXIDE AND ITS PHOTOCATALYTIC PERFORMANCE

2020, 51(6):  47-51. 

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A ring-focusing single-mode microwave synthesis method was used to rapidly synthesize a composite photocatalyst of silver-magnesium co-doped ZnO. XRD and SEM were used to characterize the structure and morphology of the synthesized photocatalyst. The photocatalytic degradation of Rhodamine B and oily wastewater by the photocatalyst was investigated. The performance and the mechanism of the reactions were explored. The results showed that the composite photocatalyst synthesized by microwave method had a good photocatalytic performance, and the degradation rate for oily wastewater was better than that of commercial titanium dioxide. After four cycles, the degradation rate of Rhodamine B was still above 92%, indicating that its chemical stability was good.

PREPARATION OF TITANIUM DIOXIDE PHOTOCATALYST BY HYDROLYSIS

2020, 51(6):  52-56. 

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TiO2 photocatalyst is one of the technologies to effectively use solar energy to solve the existing environmental pollution problems. A new titanium dioxide photocatalyst was prepared by using butyl titanate as titanium source， anhydrous ethanol as solvent，glacial acetic acid as inhibitor. The optimal value of the variable was determined by single factor method, and TiO2 photocatalyst was prepared by optimized hydrolysis method through orthogonal experiment. The degradation rate of Rhodamine B solution was used as the standard for characterization of catalytic activity, and the catalytic activity was compared with that of TiO2 prepared by sol-gel method under optimal conditions in literature. The experimental results showed that the performance of prepared photocatalyst was influenced by the volume ratio of alcohol to titanium and the calcining time in the process of hydrolysis. The catalyst samples obtained by calcination for 4 hours at 600 ℃ were the best under a water to butyltitanate volume ratio of 12:1 and an ethanol to butyltitanate volume ratio of 6:1, and the degradation rate of Rhodanine B solution reached 96.4% after full illumination.

DEVELOPMENT AND INDUSTRIAL APPLICATION OF HYDROCRAKING PRETREATMENT CATALYST THHN-1

2020, 51(6):  57-61. 

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To meet the demand of hydrogenation pretreatment for processing high sulfur and high nitrogen naphthenic materials in medium pressure hydrocracking unit, CNOOC CenerTech Tianjin Chemical Research and Design Institute Co. Ltd. has developed a new generation of hydrocracking pretreatment catalyst THHN-1 with high HDN activity by the gel method for alumina preperation and the redistribution technology for active components. The catalyst was first realized industrial application in medium pressure hydrocracking unit of CNOOC Zhoushan Petrochemical Company. The results of the laboratory and the first industrial application showed that THHN-1 catalyst had high hydrogenation and high HDN activity, better than the industrial reference agent, and was more suitable for the medium and high pressure hydrocracking to pretreat the secondary oils of marine naphthenic-based crude oils.

β-CYCLODEXTRIN MODIFIED Ni/SFCC TO ENHANCE CATALYTIC HYDROGENATION OF C9 PETROLEUM RESIN

2020, 51(6):  62-71. 

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A novel nickel-based catalyst Ni/SFCC-CD was prepared by wet impregnation of nickel nitrate using spent FCC catalyst（SFCC）as support and β-cyclodextrin（β-CD） as metal chelating agent and evaluated its catalytic activity for C9 petroleum resin hydrogenation. The physicochemical properties of the catalyst were characterized by BET，H2-TPR，and XRD techniques to investigate the action mechanism of β-cyclodextrin and its effect on hydrogenation performance. The results showed that the water-white hydrogenated C9 petroleum resin could be produced with bromine number of 1.45 gBr/（100 g） and the Gardner color number less than 1 at a temperature of 260 ℃，a pressure of 7 MPa，and a reaction time of 120 min. The Ni/SFCC-CD remained good activity after 4 cycles. The complexation of β-CD with nickel nitrate inhibits the decomposition rate of nickel nitrate, controls the crystallization process of NiO and enhances the interaction between the active component Ni and the carrier, thus improving the catalytic activity and stability of Ni/SFCC -CD.

ANALYSIS OF COMBINED PROCESS OF MIP AND LTAG TECHNOLOGIES FOR RFCC OPERATION

2020, 51(6):  72-78. 

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The adjustment of refinery configuration and upgrade of oil quality requires the refinery to adjust the processing strategy of FCC process to increase clean gasoline and reduce inferior FCC LCO. Aiming at the problems of different cracking selectivity of heavy oil and hydrogenated LCO, a dual independent reactors system, which combines MIP and LTAG technologies, was designed for revamping FCC unit. More gasoline with high octane number and aromatics were produced by precisely controlling the hydrogenation depth of LTAG process. After revamping, the RON and yield of gasoline increased significantly, while lowering the olefin content and increasing aromatic content. Meanwhile, the cetane number of LCO declined and the density of slurry increased slightly. In addition, due to the reduction of LTAG auxiliary tower slurry, the supplement of oil slurry for auxiliary fractionation tower to ensure the operation of the oil slurry system was needed.

DISCUSSION ON LARGE-SCALE CONTINUOUS CATALYTIC REFORMING UNIT

2020, 51(6):  79-85. 

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Based on the development trend of continuous catalytic reforming technology, the raw material supply and product demands of the large-scale device was first analyzed, and then discussed the different requirements for reactor, reactor internals, layout of heating furnace, selection of compressor, catalyst regeneration process and economies of scale in energy saving. The key elements for planning and designing of a large-scale continuous reforming unit were proposed. At the same time, according to the development of CCR, the idea for optimizing reforming process was suggested.

DYNAMIC ANALYSIS OF FEEDING LOW-PRESSURE SYNTHETIC GAS TO CO SHIFT DEVICE

2020, 51(6):  86-92. 

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Using dynamic simulation software, the phenomenon of over temperature duringfeeding low-pressure gas into CO shift system with high water/gas ratio for hydrogen production from coal water slurry is studied, and several common temperature control measures, including adding high-pressure steam and high-pressure boiler water, increasing the flow rate of raw syngas, and cutting off the feed and purging are analyzed. The phenomenon of over temperature duringfeeding low-pressure gas is visually displayed in theory,and the relationship between process parameters such as valve opening, flow rate of raw syngas, temperature of shift gas, degree of methanation reaction, system pressure and gas flowrate and time is also shown.Combining with practical operation experience, the applicability and suggestions of temperature control measures are given.

ANALYSIS OF LONG CYCLE OPERATION OF LCO HYDROCRACKING UNIT

2020, 51(6):  93-97. 

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In order to optimize the enterprise product structure and improve the economic efficiency, SINOPEC Anqing Company built a new 1.0 Mt/a LCO hydrocracking unit using RLG technology developed by SINOPEC Reserach Institute of Petroleum Processing to produce high octane number gasoline with relative hydrofining catalyst and hydrocracking catalyst. The unit has been operating safely for 18 months under the condition of processing 100% low quality LCO raw materials. The calibration results after long term operation showed that the yield of high octane gasoline component was 45%-60% and RON was 90-95, sulfur mass fraction was less than 2 μg/g; at the same time, the diesel cetane index was improved by 12-14 units, sulfur mass fraction was less than 5 μg/g, indicating that RLG realized the efficient conversion of FCC LCO into high octane gasoline with good qualities and diesel products and low gas yield. The adoption of RLG technology reduced the ratio of diesel to gasoline from 1.03 to 0.74, and the economic benefit was significantly improved.

CHARACTERISTICS OF FCC GASOLINE HYDROGENATION TECHNOLOGY M-PHG AND ITS APPLICATION

2020, 51(6):  98-101. 

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The FCC gasoline hydroupgrading-desulfurization combined technology （M-PHG） is one of the best technologies to produce clean gasoline, jointly developed by PetrChina Research Institute of Petrochemicals and PetrChina Research Institute of Fushun Petrochemical Company, which organically couples core technologies of FCC gasoline stepwise hydrodesulfurization and olefins directional conversion. The technology reduces the loss of octane number of FCC gasoline during desulfurization and olefin reduction, and has good adaptability for feedstock. In order to meet the quality requirements of China national VI gasoline standard phase B and optimize the composition of gasoline products, the original gasoline hydrogenation unit was retrofitted by means of M-PHG technology in CNPC Qingyang Petrochemical Company. After optimization of operation, the average reduction of the olefin volume fraction of full-distillate gasoline reached 12.1 percentage points, the mass fraction of sulfur in the product was less than 10 μg/g, and the RON loss was less than 1.0 units. After the transformation, the gasoline pool of the whole plant meets the emission standard of vehicle gasoline in phase B of national VI standard.

DEVELOPMENT OF HIGH PERFORMANCE CAPABILITY CLASS AIRCRAFT TURBINE ENGINE OIL

2020, 51(6):  102-107. 

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As the key supporting material of engine, the main development direction of aviation turbine engine oil is better high temperature stability and high temperature coking resistance. According to the SAE AS5780D performance specification, the high performance RIPP 4058 aviation turbine engine oil（4058 lubricating oil） was developed. Starting with key raw materials, the research of new polyol ester base oil and amine high temperature antioxidant was completed successively. Then the formula was optimized to improve further its high temperature stability and high temperature coking resistance, which at the same time has excellent lubrication and physicochemical properties. The performance test data showed that the 4058 oil has excellent high temperature stability, lubrication performance, and physicochemical performance and is comparable with advanced foreign products. The process control system was established to ensure the performance and quality of 4058 lubricating oil.

PERFORMANCE EVALUATION OF HIGH QUALITY ROAD ASPHALT FROM CHUNFENG-TAHE CRUDES

2020, 51(6):  108-113. 

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The quality and chemical composition of high quality road asphalt of Chunfeng Tahe were analyzed, and its PG grading and mixture performance were evaluated. The results showed that the samples have a good proportion of four components, showing moderate needle penetration index, high softening point and dynamic viscosity (60 ℃), large low temperature elongation, low wax content, large residual needle penetration ratio and residual low temperature elongation. The sample has good performances in temperature sensitivity, heat resistance aging performance, resistance to high temperature deformation, low temperature crack resistance and fatigue resistance, especially at low temperature crack resistance, belonging to PG 64-28 classification and is suitable for application in Xinjiang.

STUDY ON ENERGY SAVING OPTIMIZATION FOR SOLVENT RECOVERY SYSTEM OF KETONE BENZOL DEWAXING UNIT

2020, 51(6):  114-119. 

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The influence factors on energy saving optimization for solvent recovery system of ketone benzol dewaxing unit were explored by NRTL physical property method and Aspen Plus process simulation software. The effects of ketone/benzene ratio, water content, and key heat exchangers on energy consumption of the plant were analyzed to find the optimal steam energy utilization. The results showed that when the ketone/benzene mass ratio was controlled at 0.65 and the water content was controlled at 0.3%, the total steam consumption was reduced by 5.63%, and thus the proportion of steam output of the primary, secondary, and tertiary flash tower was 22.39: 26.98:50.63. On this basis, if the vaporization rates of hot discharge of two key heat exchangers were reduced to 0, the effective heat transfer area of the two exchanges would increase by 27.16% and 13.36%, respectively, and the total heat load would reduce by about 24.39%.

RESEARCH PROGRESS ON INFLUENCE OF LUBRICATING OIL ADDITIVES ON LOW SPEED PRE-IGNITION OF GASOLINE ENGINE

Jing Ma Liu Yinong Shuo Su

2020, 51(6):  120-124. 

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The low-speed pre-ignition severely restricts the combustion efficiency of gasoline engines. Among factors affecting the low-speed pre-ignition, lubricant additives play a vital role. The effects of the additives containing calcium, zinc, molybdenum, magnesium, and sodium on low-speed pre-ignition of engines and the mechanisms are reviewed. In order to reduce the frequency of low-speed pre-ignition, optimization measures in composition and formula of lubricant additives are suggested.