Table of Content

12 March 2020, Volume 51 Issue 3

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APPLICATION OF REACTOR CROSS LINE IN CAPACITY EXPANSION OF CONTINUOUS CATALYTIC REFORMING UNIT

2020, 51(3):  1-5. 

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The application of reactor cross-line for capacity expansion of a continuous catalytic reforming unit was introduced. During revamping, the bottlenecks such as catalyst attachment on the reactor wall, insufficient heat load of heating furnace for the reactor and insufficient coke removing capacity of the regenerator were encountered. Theoretical calculation and comparison of operation data before and after expansion proved that the addition of reactor cross-line could effectively avoid the phenomenon of catalyst attachment and reduce the heating load of downstream furnace, indicating that the method is a new technical solution for the capacity expansion of CCR unit.

SEPARATION OF ALKANES FROM NAPHTHA BY COUPLED ADSORPTION PROCESS OF 5A AND ZSM-5 ZEOLITES

2020, 51(3):  6-12. 

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To improve the utilization efficiency of naphtha in production of ethylene and aromatics, a continuous adsorption and separation process using 5A and ZSM-5 zeolites for separation of alkanes from naphtha was studied. The residue oil with removed n-alkanes by adsorption (abbreviated as de-alkanes oil) and the oil removed monomethyl isomeric paraffins (abbreviated as de-paraffin oil) were obtained, respectively. The alkane-rich component oil （abbreviated as desorption oil）was obtained by desorption from molecular sieves using nitrogen. The results showed that the mass fraction of normal alkanes, monomethyl isomeric alkanes and aromatics potential content in the de-paraffin oil were 0.1%, 3.8%, and 53.4%, respectively, which can be used as a high quality feedstock for catalytic reforming. The content of alkanes in desorption oil can reach over 84%, which can be used as a high quality feedstock for cracking to ethylene.

STUDY OF QUALITY IMPROVEMENT OF HEAVY DEOILED WAX

2020, 51(3):  13-17. 

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Simultaneously producing base oil and de-oiled wax are the main measures to increase the economic benefits for the traditional base oil production. However, the quality of the de-oiled wax from vacuum cut 4 produced by reverse scheme is poor for its high impurity content and makes the difficulties in wax refining process to achieve the wax quality index. The study for the wax showed that by refining with selected clay followed by hydrofinishing as well as adding antioxidants and UV inhibitors could improve the color and light stability of refined wax. A process scheme for refining inferior heavy de-oiled wax was proposed.

STUDY ON REFINERY HEAVY DISTILLATE OIL AS FEED TO STEAM CRACKING UNIT

2020, 51(3):  18-21. 

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The cracking properties of heavy feedstocks, such as hydrocracking tail oil, atmospheric second and third cut oils, vacuum distillation first and second cut oils were evaluated under the conditions of different temperatures with water to oil ratios of 0.8 in a small scale steam cracking simulation device. The results showed that with the increase of cracking temperature, the ethylene yield increased gradually, while the propylene yield decreased, the yields of diene and triene increased first and reached maximum at 810 ℃and then decreased. The hydrogenation tail oil had the highest yield of ethylene, propylene, and butadiene, indicating the best cracking performance, followed by the atmospheric second cut oil and the third cut oil, and the vacuum fractions (the first and second cut oil) were the worst.

REVAMPING OF GAS OIL HYDROCRACKING UNIT TO PRODUCE INDUSTRIAL WHITE OIL

Zeng Wenqin Fang You Zheng Gangxi Zhao Chenxi

2020, 51(3):  22-26. 

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In view of the current situation of poor economic benefits of diesel products, starting from the study on the properties of diesel and its narrow fractions of 4.0 Mt /a gas oil hydrocracking unit of Huizhou Petrochemical Company, it was found that the middle fraction of the diesel product was suitable for the production of No. 5 industrial white oil with better economic benefits. Therefore, the distillation system of the unit was simulated and evaluated, and the optimization measures were proposed and implemented, such as reducing the pressure of the main fractionation column to below 0.1 MPa and increasing the reboiler returning temperature of the diesel stripper. However, these measures based on existing facilities failed to raise the initial boiling point of diesel to the target value. In order to produce No.5 industrial white oil, the 220-360 ℃ fraction of diesel products was cut off and used as a raw material. Two techniques: (i) adding a steam stripper to the diesel side-line stripper flow,（ii）stopping the original reboiler of the diesel side-line stripper to use steam stripping, were proposed. The results showed that both proposals could increase the initial boiling point of diesel to 220 ℃ and produce the qualified No.5 industrial white oil. It is proved that revamping measures are helpful to turn diesel into white oil product with better economic benefits and improve the economic benefits of the whole plant.

APPLICATION OF CATALYTIC REFORMING CATALYST SR-1000 IN KAZAKHSTAN REFINERY

Wang Jiaxin Jiang Shi Zang Gaoshan Jia Yiming Guo Menglong

2020, 51(3):  27-31. 

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The SR-1000 catalyst developed by SINOPEC Research Institute of Petroleum Processing was applied in the 1.0 Mt/a semi-regenerative reforming unit of PKOP Refinery in Shimkent，Kazakhstan of "one Belt and one Road ". The calibration results after 6 months operation showed that the RON of stable gasoline was 96.3 and the yield was 0.2 percentage point higher than that of the protocol under the conditions of the designed full load of 125 t/h and the WABT less than 485 ℃. Compared with the foreign catalyst R, the activity and selectivity of SR-1000 catalyst were better under the conditions of basically the same operating time and the feed with the cycloalkanes and aromatics content of raw materials 1.49% higher, and the WHSV of 21% higher. The starting-up method of SR-1000 catalyst is simple, which can not only significantly shorten the starting time, but also be safe and environmentally friendly, and can reduce the starting-up risk. The results of industrial application showed that SR-1000 catalyst has good activity，selectivity and stability in the production of high octane gasoline blending components，which can meet the needs of long-term stable operation of reforming unit under high stringent conditions.

RESEARCH AND INDUSTRIAL PRODUCTION OF HYDROGENATION CATALYST SUPPORTS PREPARED BY GEL-EXTRUDING METHOD

2020, 51(3):  32-37. 

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Catalyst supports were prepared by gel-extruding method and the industrial scale production were carried out. Supports and catalysts prepared by gel-extruding method and conventional method, respectively, were analyzed by BET, NH3-TPD, H2-TPR and hydrogenation reaction activity test. Compared with the conventional method, supports and catalysts prepared by gel-extruding method had a great increase on pore volume and surface area, while the bulk density reduced. The total acid amount and the mid-strong acids were increased. The interaction force between metal and support of the gel-extruding catalysts was reduced and the utilization of metals was improved, and the activity was obviously superior to the catalyst prepared by the conventional method. The industrial production of the gel-extruding supports and THDS-3 catalyst thereof were carried out successfully. The THDS-3 catalyst has been commercially applied with good results.

COMMERCIAL APPLICATION OF DOMESTIC TiO2-BASED CLAUS CATALYST IN PURIFICAITON OF HIGH H2S CONTENT NATURAL GAS

Hu Liangpei Zhang Wenbin Du Li Wei Jinghui Huang Kun

2020, 51(3):  38-42. 

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The second unit with a capacity of 20 kt / a (122 series) for sulfur recovery in the No.2 complex unit of Natural Gas Purification Plant of SINOPEC Dazhou Natural Gas Purification Co., Ltd. has started industrial trials using domestic TiO2-based Claus catalyst LS-981G since April 2018. The practical results of the device running for one year showed that the catalyst LS-981G had a good performance, the total hydrolysis rate of carbonyl sulfur was above 98%, the total hydrolysis rate of carbon disulfide was 100%, and the total sulfur recovery rate was above 99.96%. The mass concentration of SO2 in the flue gas emission was less than 400 mg / m3, which is far lower than the reqirement（not exceeding 960 mg/m3）of the GB16297-1996 “Comprehensive Air Pollutant Emission Standard”.

CATALYTIC PERFORMANCE OF CATALYSTS RL-2 IN HIGH PRESSURE HYDROTREATING OF LUBRICATING OIL

2020, 51(3):  43-47. 

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RL-2 catalyst was applied in the first reactor of No.1 high pressure hydrotreating unit of PetroChina Karamay Petrochemical Co., Ltd. in Aug. 2018 during plant turnaround. After sulfidation and initial activity stabilization, the catalyst was transferred to normal operation. At the initial stage of application, on the premise of ensuring the product quality, RL-2 catalyst entered the stable period of high catalytic activity fast and showed a good adaptability for different feedstock. Nearly one year operation indicated that RL-2 catalyst had good activity stability. The oil yield under each feedstock scheme remained at a high level.

STUDY OF HYDROGEN SOLUBILITY IN RICP PROCESS

2020, 51(3):  48-53. 

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The vapor-liquid equilibrium of H2-residue-aromatics of RHT process was built based on the Aspen Plus software, which aims at figuring out the influence of various kinds of aromatics as solvent on the amount of soluble hydrogen in the liquid phase. Naphthalene, anthracene, chrysene, pyrene, and HCO were tested. The results showed that hydrogen solubility in the liquid phase increased after the addition of aromatics solvent; hydrogenation of residue resulted in the further raise of hydrogen solubility in residue compared with the residue feedstock. Based on the knowledge that aromatic solvents are in favor of asphaltene stability, it was found that the increase of hydrogen solubility has negative effect on the asphaltene stability. The results provide a deeper understanding of the effect of aromatic hydrocarbons on the stability of asphaltenes in RICP process.

STUDY ON CHARACTERISTICS OF GAS-LIQUID TWO-PHASE FLOW IN SWIRL ATOMIZING NOZZLE

2020, 51(3):  54-61. 

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By means of experiment and numerical simulation and diethylene glycol as test material, the gas-liquid two-phase flow characteristics in a swirl atomizer nozzle were studied, the flow mechanism in swirl atomizer nozzle was revealed, and the atomizing characteristics in the swirl atomizer nozzle were predicted effectively. The RSM turbulence model and the Euler-Euler multiphase flow model were used in the numerical simulations. The results showed that when the gas/liquid ratio was 600 and the gas flow rate was less than 25 m3/h, the simulation results were in good agreement with the experimental data. Due to the decrease of flowing area, the tangential velocity of diethylene glycol inside the swirl nozzle increased rapidly, and reached a peak value in the throat area. After that, the tangential velocity decreased gradually due to the increase of the flow area. With the increase of gas flux, the speed range of diethylene glycol was farther and farther. When the gas flow rate were 15, 20 and 30 m3/h, the distributing uniformity of diethylene glycol were 27.94%, 26.05% and 33.42%, respectively, showing a trend of decrease first and then increase.

EFFECT OF SURFACTANT ON RHEOLOGICAL PROPERTIES OF CRUDE OIL AND MOLECULAR DYNAMICS SIMULATION

2020, 51(3):  62-68. 

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Five surfactants (acrylic acid, acrylamide, maleic anhydride, vinyl acetate and styrene) commonly used as synthetic pour point depressants were selected and the effects of these surfactants on the rheological properties of crude oil were investigated by means of experiments and molecular dynamics simulation.The results showed that at the dosage of 2000ug/g, the addition of 5 surfactants had little effect on the freezing point of crude oil, which increased the freezing point of crude oil by only 1℃; but the effect on the viscosity and yield value of crude oil was significant, the relative degree of influence as follows: acrylamide>acrylic acid>styrene>maleic anhydride>vinyl acetate; compared with the blank crude oil system, the potential energy of the crude oil systems with five additives decreased, and the non-bond energy increased negatively. The order of the effect was consistent with the experimental results. The mechanism of the effect of surfactant on the rheology of crude oil was explained from the molecular level.

SYNTHESIS OF ASYMMETCICAL HINDERED PHENOL ANTIOXIDANT AND ITS PERFORMANCE

2020, 51(3):  69-72. 

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Antioxidant is one of the most important additives in lubricating oils, among which the asymmetric hindered phenol antioxidant is a hot research topic in recent years. As a new kind of high efficiency antioxidant, it has been applied gradually and achieved better effect than the traditional hindered phenol antioxidant. Asymmetric hindered phenol 2-tert-butyl-5-pentadecylphenol was synthesized from 3-pentadecylphenols and tert-butyl chloride by alkylation process. The structure of synthetic product was characterized and its antioxidant properties in mineral base oil and synthetic base oil were investigated. The results showed that the 2-tert-butyl-5-pentadecylphenol has advantages of strong oxidation resistance and good sensitivity in synthetic base oils，and its comprehensive performance was better than the commonly used hindered phenol lubricant antioxidant.

STUDY ON STATIC THERMAL AGING PROPERTIES OF TITANIUM COMPLEX GREASE

2020, 51(3):  73-79. 

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The static thermal aging method was used to simulate the thermal aging process of titanium complex grease in continuous and intermittent operation mode at 150℃ and 200℃, respectively. The physicochemical and rheological properties of titanium complex grease after aging were analyzed. Combined with the changes of internal characteristic structure, the static thermal aging performance of the grease was studied. The results showed that the aging temperature had a great influence on the properties of the grease and the effect of continuous thermal aging on the performance was greater than the intermittent mode. The mechanism of the influence of different aging temperatures on the properties was different. The thermal aging at 150℃ showed a physical process of unwinding the titanium complex grease soap fiber structure, and its infrared spectrum was in good consistency with the results of fresh grease samples. The aging at 200℃ was mainly attributed to the thermal oxidation of the thickener and the unwinding and fracture of the titanium soap fiber.

APPLICATION OF ACTIVATED CLAY IN BLEACHING OF TRANSFORMER OIL

2020, 51(3):  80-84. 

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In this study, activated clay was used as an adsorbent in the bleaching process of transformer oil, and the effects of adsorption temperature, amount of activated clay and adsorption time on the oil color were discussed. The color changes of the oil samples were analyzed by colorimeter and spectrophotometer, and the structures of the activated clay before and after adsorption were characterized by infrared spectroscopy (IR), thermogravimetry analysis (TG) and scanning electron microscopy (SEM). The results showed that the activated clay had excellent decolorization effect on transformer oil. At the conditions of activated clay amount of 5%, the adsorption temperature 90 ℃ and the adsorption time of 1.5 h, the color number of transformer oil could decrease from 9 to 1 and the light transmittance was over 90%. The breakdown voltage increased by 56.64%, the dielectric loss factor decreased by 18.81%, and the moisture content decreased by 25.69%.

DETERMINATION OF CERIUM IN SULFUR TRANSFER ADDITIVE FOR FCC FLUE GAS BY ICP-AES

2020, 51(3):  85-88. 

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The sulfur transfer additive for FCC flue gas was treated by microwave-assisted digestion using hydrochloric acid and the content of cerium in the additive was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The kinds and compositions of digestion solution and the digestion temperature were investigated to optimize the microwave-assisted digestion procedure. The interelement interference in ICP-AES analysis was analyzed to determine the precision and accuracy of the method. The results showed that 0.05 g sulfur transfer additive was completely digested by 12 mL hydrochloric acid with a mass concentration of 36%-38% under the optimal digestion conditions. After sample digested, the content of cerium was determined by ICP-AES. The detection limit of ICP-AES method for analyzing the content of cerium in sample solution was 0.01mg /L, the linear range of standard curve was 0.01mg /L with a linear correlation coefficient of 0.999 95; the relative standard deviation (RSD, n = 6) was less than 4%, and the method recovery was between 93.1% and 101.0%

FAST DETERMINATION OF SILICON CONTENT IN GASOLINE BY HF-XRF

Zhang Ran Wu Mei Wang Jieming Liu Mingxing

2020, 51(3):  89-93. 

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A method for fast determination of silicon content in gasoline by HF-XRF was developed. The precision of this method was inspected. The results showed that the linear correlation coefficient was more than 0.999 9 when the mass fraction of the silicon was 0-100 μg/g. The detection limit was 1μg/g for silicon，the standard addition recovery was in the range of 95.7%-103.0%，and the relative standard deviation was less than 5.79%. The results showed that this method is suitable for determination of silicon in gasoline.

MODIFICATION AND COMMISSION OF BENCH-SCALE FIXED FLUIDIZED BED EVALUATION DEVICE

2020, 51(3):  94-98. 

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A newly purchased small fixed fluidized bed FCC evaluation unit was installed, debugged and modified. The installation position of the preheater was changed, and the connection pipeline between the preheater and the reactor was shortened. The results showed that after revamping, the repeatability of product distribution was improved. The stability of the rotor flowmeter was improved and the drag and delay of CO2 curve caused by flow fluctuation and gas resistance of CO2 infrared analyzer was reduced by increasing the gas condensation depth at the front of the CO converter, leading to a good repeatability of coke data. By increasing the pressure of the device system, the production rate of LPG and propylene were reduced, the results close to the data of the industrial device. The revamping work can better guide the selection of catalyst formulation and the comparison of performance

SIMULATION ON EXPLOSION ACCIDENT CONSEQUENCES OF LPG LOADING AND UNLOADING STATION BASED ON COMPUTATIONAL FLUID DYNAMICS

2020, 51(3):  99-102. 

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Taking the loading and unloading station of liquefied gas vehicles in a enterprise as an example, computational fluid dynamics（CFD）simulation was used to establish a full-size 3D model in view of the dangerous characteristics of liquefied gas. Simulation calculation for explosion was carried out on the scene duo to LPG leakage and vapor cloud accumulation in the nearby parking lot to evaluate the impact of explosion on the surrounding buildings, and to analyze the relationship between the number of parking lots and the explosion overpressure. The results showed that the non-explosion-proof control room and other structures would be damaged and collapsed by explosion within a certain distance, threatening the safety of workers in the control room. The explosion overpressure was linearly related to the number of vehicles in the parking area, therefore the number of vehicles in the loading and unloading area should be limited.

APPLICATION AND ANALYSIS OF HEAVY WASTE OIL TREATMENT TECHNOLOGY SOTU

2020, 51(3):  103-106. 

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SOTU (Slop Oil Treatment Unit) is a new heavy dirty oil treatment technology, which adopts a multi-stage cycle treatment process. After demulsification and nucleation by ultrasonic demulsification, sub-high-frequency vibration and high-energy electron beam in the pretreatment part, the solid impurities are removed in the first stage separation, and water is removed in the second stage separation, then the waste oil is transported to the device or returned to the original tank for refining. The density difference of heavy dirty oil and water of Tahe Refining and Chemical Co. is small, and the content of solid impurity is high, which is difficult to deal with by traditional process. After treatment by SOTU, the water content of dirty oil is 1.45%(w), and the oil content of treated sewage is 49.3 mg/L, which is better than the target that the water content of dirty oil is less than 3.0%, and the oil content of treated sewage is less than 150 mg/L.