Table of Content

12 June 2021, Volume 52 Issue 6

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INDUSTRIAL APPLICATION OF FCC CATALYST FOR IMPROVING RING-OPENING REACTION TO PRODUCE HIGH OCTANE GASOLINE

2021, 52(6):  1-5. 

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The industrial application of ROC-1 catalyst for improving ring-opening reaction to produce high octane gasoline in SINOPEC Qilu Company was described.The first application showed that the yield of gasoline increased by 0.43 percentage point with RON improvement of 0.6,the liquid yield increased by 1.27 percentage points,the yield of coke decreased by 0.68 percentage point under uniform operating condition.The distribution of product was significantly improved through increasing the yield of high octane gasoline and decreasing coke selectivity.The apparent selectivity of the ring-opening cracking reaction of polycyclic naphthenes and napthenic aromatics increased by 18.37%.ROC-1 catalyst has stronger ability to promote the conversion of polycyclic naphthenes and napathenic aromatics,and is suitable for processing of catalytic cracking feedstock rich in naphthenes.

PREPARATION OF CATALYTIC MATERIAL WITH HIGH PORE VOLUME AND LARGE PORE SIZE FOR RESIDUE HYDROTREATING

2021, 52(6):  6-10. 

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The precursor of alumina, ammonium aluminum carbonate hydroxide (AACH) with the chemical composition corresponding to NH₄[AlO(OH)]₂HCO₃^.2H₂O, was prepared from aluminium sulfate solution and ammonium bicarbonate solution through chemical coprecipitation method. The effect of pH and temperature on the preparation of AACH was studied on the basis of the precipitating mechanism. The prepared alumina from calcination of AACH showed high pore volume and large pore size,was suitable to be used as the support material of residue hydrotreating catalyst, and could also be compounded with other pseudo-boehmites to form supports with different pore structures to meet different requirements. The results of activity evaluation and commercial application showed that the residue hydrodemetallization catalyst based on the AACH had good performance of demetallization and reduction of carbon residue.

PREPARATION AND PERFORMANCE OF CATALYST FOR AROMATIZATION OF METHANOL COUPLING WITH RAFFINATE

2021, 52(6):  11-17. 

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Co-crystallized ZSM-5/ZSM-11 zeolite was prepared by one-step hydrothermal method, which was simple, rapid and easy to be industrialized. The samples were characterized by XRD, N₂ adsorption-desorption, Py-IR, SEM and TEM techniques. The results showed that the synthesized sample was ZSM-5/ZSM-11 co-crystallization zeolite with hierarchical pore structure, specific surface area of 358 m²/g, pore volume of 0.35 cm³/g, and B/L acid amount ratio of 2.07.And the crystalwas composed of regular, sharp-edged spheres with rod-shaped hexagonal cylinders. The formulated catalyst, by mixing the ZSM-5/ZSM-11 zeolites with alumina, was used in the aromatization reaction of methanol coupling with raffinate.Under the conditions of a reaction temperature of 380 °C, a reaction pressure of 0.5 MPa, a mass ratio of methanol to raffinate of 1:1 and a mass space velocity of 1 h^-1, the yield of C₅+ was over 81% withthe yield of aromatics up to 38%. Therefore, the ZSM-5/ZSM-11 co-crystallization zeolite has a good industrial application prospect in the catalytic aromatization of methanol coupling with raffinate.

INDUSTRIAL APPLICATION OF ULTRA-DEEP DESULFURIZATION CATALYST RS-3100 WITH HIGH STABILITY IN DIESEL HYDROGENATION UNIT

2021, 52(6):  18-23. 

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RS-3100 catalyst，a new highly stable ultra-deep hydrodesulfurization catalyst developped by SINOPEC Research Institute of Petroleum Processing,was applied in the 1.2 Mt/a diesel hydrogenation unit of SINOPEC Jiujiang Company for the first time. The unit was successfully started up in April 2020 to process the mixed feedstocks of CGO, LCO and SRGO. The sulfur mass fraction of diesel products is less than 10 μg/g and the mass fraction of polycyclic aromatic hydrocarbons is less than 7%, which can meet the requirements of China Ⅵ vehicle diesel standard. The industrial calibration results showed that RS-3100 catalyst had good activity and stability, and could be used to process 50% inferior feedstocks of secondary oil, and produce China Ⅵ vehicle diesel stably.

FIRST APPLICATION OF TRULY SULFURIZED HYDROCRACKING CATALYST

2021, 52(6):  24-29. 

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The truly sulfurized (e-Trust)hydrocracking catalysts RHC-131B-TS, RHC-133B-TS for maximizing jet fuel and heavy naphtha and their grading scheme,developed by the SINOPEC Research Institute of Petroleum Processing,was applied commercially in the hydrocracking unit of PetroChina Harbin Petrochemical Company. The unit mainly produces jet fuel distillates, and also produces naphtha and diesel distillates. The application results showed that the time of start-up was shortened about 2 days by using the true sulfurized catalyst, no waste water or exhaust gas were discharged in the process of start-up, the yield of distillate (heavy naphtha + jet fuel) was 71.5%, the smoke point of jet fuel fraction was 35 mm, and the cetane number of diesel fraction was 76. During the long-term operation of the unit, the activity of the true sulfurized catalyst was stable, the product quality was excellent and the product distribution could meet the production demand.

DEACTIVATION ANALYSIS AND REGENERATION PERFORMANCE OF VACUUM GAS OIL HYDROFINING CATALYST

2021, 52(6):  30-38. 

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Deactivation analysis and regeneration performance investigation were carried out on the catalyst which appeared obvious deactivation in the first catalyst bed of the reactor in a vacuum gas oil hydrofining unit of a refinery. The fresh catalyst,deactivated catalyst after toluene extraction and the regenerated catalyst were detected by means of X-ray fluorescence spectrometer (XRF)，specific surface area and aperture analyzer，and X-ray photoelectron spectroscopy (XPS) . The results showed that the specific surface area and pore volume of the deactivated catalyst decreased obviously ，and the pore volume of regenerated catalyst was obviously recovered, but the specific surface area was not recovered completely. The main reason for the deactivation of the catalyst was that the inorganic materials containing P, Fe and Si elements were deposited on the surface of the catalyst, which blocked or deposited in the catalyst channel. Compared with the fresh catalyst，the deactivated catalyst had no catalytic activity，and the regenerated catalyst showed some initial activity，but the activity dropped sharply，so the deactivated catalyst was permanently deactivated.

DEVELOPMENT AND APPLICATION OF HYDROGENATION CATALYST EK-Ⅲ FOR PRODUCING HYDROGEN PEROXIDE THROUGH ANTHRAQUINONE ROUTE

2021, 52(6):  39-43. 

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A new hydrogenation catalyst EK-Ⅲ for producing hydrogen peroxide (H₂O₂) through anthraquinone route was developed by using self-made spherical alumina support and proprietary technology. The catalyst has the characteristics of large specific surface area(more than 170 m²/g), low bulk density (0.42 g/mL), and widely and enriched palladium distribution with the thickness of palladium of only 60—70 μm. The industrial application of the catalyst EK-Ⅲ in Jilin Shuang’ou Chemical Industry Co., Ltd. shows that compared with a domestic industrial product catalyst R, the capacity of hydrogen peroxide per ton of catalyst is still more than 20% higher when the loading amount of EK-Ⅲ catalyst is less than 30%,showing that the EK-Ⅲ catalyst is featured ashigher activity, the better selectivity, and longer stable operation cycle.

STUDY OF PRODUCTION OF ACETYLENE BY PYROLYSIS OF INFERIOR OIL AT HIGH TEMPERATURE

2021, 52(6):  44-49. 

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In view of the characteristics of low-value intermediate products in catalytic cracking, the reaction performance of catalytic cracking of low-value products from three different sources to produce acetylene at high temperature was investigated in a self-made electromagnetic induction high-frequency and high-temperature cracking unit. Reaction temperature and residence time were main factors restricting pyrolysis of inferior oil at high temperature for acetylene production. Using light cycle oil from SINOPEC Beijing Yanshan Company as feed for high temperature cracking reaction, the results showed that at the conditions of a feed rate of 0.3 g/min, a reaction temperature of 800 ℃, and a residence time of 8 ms , the acetylene yield reached 7.90%. Hydrogen was by-product of LCO pyrolysis to produce acetylene, and yield of hydrogen reached 7.54% when the reaction temperature was 1 300 ℃ and the residence time was 50 ms. Increasing the content of alkane and hydrogen in the raw materials was beneficial to the formation of acetylene. Under the conditions of a feeding rate of 0.3 g/min, a reaction temperature of 1 400 ℃ and a residence time of 22 ms, the acetylene yields were 11.13% and 12.70% using hydrogenated LCO from SINOPEC Shijiazhuang Refing and Chemical Company and heavy cycle oil from SINOPEC Yangzhou Companyas feed, respectively.

ANALYSIS AND OPTIMIZATION OF LONG-TERM OPERATION OF HEAVY OIL HYDROGENATION UNIT

Sun Lei

2021, 52(6):  50-56. 

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The 2.0 Mt/a heavy hydrotreating unit of SINOPEC Anqing Company was based on the RHT technology developed by SINOPEC Research Institute of Petroleum Processing (RIPP) and designed by SINOPEC Engineering Incorporation. At present, the unit has been running to the 5th cycle, all using the RHT series residue hydrotreating catalysts developed by RIPP. The operation results of the unit showed that the performance of RHT catalysts could meet the requirements of desulfurization and denitrification in all five production cycles. The activity and stability of the catalyst could be further improved on the premise of reducing the bulk density of the catalyst. In order to prolong the operation period of the hydrotreating unit，a number of measures were taken to optimize the unit operation so as to reduce the pressure drop rise rate of the reactor，to make full use of the performance of catalyst and to ensure the long-term safe and stable operation of the unit.

OPERATION OPTIMIZATION OF A 4.0 Mt/a VGO HYDROCRACKING UNIT

2021, 52(6):  57-63. 

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The 4.0 Mt/a VGO hydrocracking unit of Zhejiang Petrochemical Company adopted UOP’s UnicrackingTM hydrocracking technology with the graded catalysts of the hydrotreating catalysts HYT-6219 and hydrocracking catalyst HC-185LT. Since the start-up, the unit has been running stably at over 95% of the load. Based on the research and summary of the unit operation optimization, the average amount of 57 t/h of RFCC diesel and coker diesel was blended as feed, and all the products were qualified, the yield of （heavy naphtha + jet fuel + diesel）was increased by 5.17 percentage points．The No. 5 industrial white oil (I) with kinematic viscosity of 4.345 mm²/s and flash point (open cup) of 126℃ was produced from the diesel side line of fractionator．The yield of jet fuel was increased from 20.7% to 26.6%, and the production was increased by 35.5 t/h compared with the design．The F0 pentane foaming agent with isopentane content of 99.20%andtotal pentane content of 99.66% was produced on deisopentanizer．Through a series of optimized operation, the value added product and the output of the unit were improved, and the overall operation economy of the unit was significantly increased．The advantages of flexible product structure adjustment of VGO hydrocracking unit in refining and chemical integration project were achieved．

REMOVAL OF MERCAPTAN FROM TRANSFORMER OIL BY MOLECULAR SIEVE

2021, 52(6):  64-70. 

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The experimental oil was prepared by adding corrosive n-dodecanethiol to the new transformer oil. The adsorptive desulfurization of the experimental oil was studied by using different molecular sieves as absorbent materials. The effect of type and size of molecular sieves, dosage, temperature and time of adsorption treatment on the removal of corrosive sulfur from test oil was investigated. The results showed that the optimum treatment conditions were as follows: a diameter of 13X zeolite of 0.5-1.0 mm, a dosage(w) of 13X zeolite of 6%, a treatment temperature of 30 ℃, a treatment time 4 h for 2 times of adsorption . Under the optimum conditions, the removal rate of corrosive sulfur in the test oil by 13X zeolite reached 98.1%. Compared with activated carbon, 13X zeolite was more effective in removing corrosive sulfur from transformer oil. The treated transformer oil was non-corrosive and could provide better performance.

STUDY OF CHLOROHYDRINATION OF ALLYL CHLORIDE TO DICHLOROPROPANOL CATALYZED BY TITANIUM SILICALITE

2021, 52(6):  71-78. 

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Traditional methods of preparing dichloropropanol have many problems, such as serious environmental pollution, low utilization of chlorine atom and harsh reaction conditions. In this work, a new process for chlorohydrination of allyl chloride with H2O2 as the oxidant and HCl as the chlorine source in the presence of HTS zeolite was developed to produce dichloropropanol. The effects of catalyst type, material ratio, temperature and catalyst dosage on the conversion of allyl chloride and the selectivity of dichloropropanol in the product were investigated, and a reaction mechanism was proposed based on the results. HTS zeolite showed excellent performance in this catalytic chlorohydrination process and the reaction of HCl with the epoxidation intermediate on the surface of MFI-type tetracoordinated titanium was carried out by the interaction between HCl and HTS, and efficient conversion of allyl chloride to dichloropropanol.

SYNTHESIS AND THEORETICAL CALCULATION OF TITANIUM-BASED GREASE COMPLEXING WITH TEREPHTHALIC ACID / STEARIC ACID

2021, 52(6):  79-86. 

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Titanium complex grease was successfully prepared in the laboratory by reaction of terephthalic acid/stearic acid with titanium tetraisopropanol in lube base oil. The molecular structure, reactivity and properties of the titanium complex grease were simulated by quantum chemical calculation method. The structure of titanium complex grease was determined by combining the infrared spectrum of quantum chemical calculation with the infrared spectrum of experimental test. The results showed that the infrared characteristic absorption peaks obtained from the theoretical calculation of vibration frequency of titanium complex grease were in good agreement with the experimental values, which indicated that the model of corresponding compounds was reasonable. At the same time, the orbital interaction and reaction mechanism of titanium tetraisopropanol, terephthalic acid and stearic acid were obtained through theoretical calculation, which provided a theoretical basis for further study on the structure of titanium-based grease.

STUDY OF PARTICLE SIZE ANALYSIS METHOD OF S Zorb ADSORBENT

2021, 52(6):  87-91. 

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Three different types of Malvern laser particle size analyzer were used to investigate the effects of particle refractive index, shading index, stirring rate of disperser, ultrasonic wave and window cleanliness on the particle size distribution of S Zorb adsorbent. The optimum conditions for particle size analysis of S Zorb adsorbent covered a particle refractive index of 2.18―1.0i, a shading index of 10%—15%, and a stirring rate of 3 000 r/min using MS3000 laser particle analyzer with HydroEV wet disperser,a stirring rate of 2 500 r/min using MS2000 laser particle analyzerwith HydroMU wet disperser,or a stirring rate of 900 r/min using MS2000 laser particle analyzer with 2000G wet disperserand conveying pump speed of 2 200 r/min, respectively. Ultrasonic dispersion will seriously damage the original appearance of adsorbent particles, so ultrasonic should not be used in the test. The cleanliness of the window of the laser particle analyzer has a great influence on the particle size analysis results of the adsorbent. The suitable pretreatment condition of the spent adsorbent is drying at 200 ℃ for 8 h. Too high pretreatment temperature will cause sintering of particles, leading to wrong results of particle size distribution.

VIRTUAL SAMPLE GENERATION METHOD AND ITS APPLICATION IN REFORMING DATA MODELING

2021, 52(6):  92-95. 

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The yield of aromatics was predicted based on a Decision Tree Regression model, which was trained using actual feed composition data from a continuous reformer. The relatively concentrated sample range of industrial data can lead to over-fitting which limits the model’s application. The small sample issue can be seen as a common problem when dealing with industrial data. A virtual sample of reforming feed was constructed with Multivariate Gaussian probability distribution method, and the corresponding aromatics yield was simulated with HYSYS mechanism model to improve the problem mentioned above. After the Decision Tree Regression model training with feed composition mixed virtual data and real data, the mean absolute error of the test sample was reduced from 1.4097 to 0.6318, which proves that virtual samples can be used for model training to expand the application of data-driven models.

PROCESS SIMULATION AND OPTIMIZATION OF 600 kt/a GAS FRACTIONATION UNIT

2021, 52(6):  96-102. 

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Aspen Plus process simulation software based on SRK thermodynamic equation- physical properties of the BM algorithm and RadFrac rectification tower module was used to simulate and optimize a 600 kt/a gas separation unit in PetroChina Sichuan Petrochemical Co. Ltd. The software was to improve the efficiency of the plate, and to simulate the influence on the quality of the product from depropanizer and propylene rectification tower, including the optimization of the bottom temperature, the parameters of reflux and the feed plate. The results showed that the feed mainly composed of propylene and propane had little difference with the result of simulation, leading to an increasing on yield of propylene by 0.43 percentage point, when the temperature at the bottom of the depropanizer tower was (103.8±0.1) ℃, the flow rate at the top was (95±5) t/h, and the feed plate kept the 29th layer. The purity of propylene was increased by 0.07 percentage point when the feed temperature of the column was 40.3 ℃, the bottom temperature of the column was 54.8 ℃, the top flow rate was 357 t/h, and the feed plate position was changed to the 136th layer. During optimization process, heat saving at the bottom of the tower reduced the operation cost of the unit by about 9.045 million CNY/a. The production of propylene and the economic benefits were increased by about 2117.39 t/a and about 15.245 million CNY/a, respectively.

BIO-DENITRIFICATION FOR TREATMENT OF WASTEWATER FROM FCC LoTOx UNIT

2021, 52(6):  103-107. 

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Waste water discharged from FCC LoTOx unit has the characteristics of highly saline and total nitrogen (TN). TN value exceeds the maximum emission standard limit, but the problem is difficult to be solved because the saline wastewater could shock wastewater treatment system. As a result, exploring a kind of economical & proven technology has significant meaning for setting a demonstration to other enterprises encountering similar problems. Based on analyzing and summing up the wastewater quality, biological filter technology with three-stage process (AOO) is proven useful for bio-denitrification. As a point, salt tolerance of biofilm depends on microbial cultivation and acclimation but not using commercial engineering bacteria. According to the experimental results, the average NO3-N removal rate is up to 94.8% when the wastewater is diluted one time for treating. Industrial unit with acapacity of 20 m3/h was built, which could remove 70% TN from the wastewater. All water quality parameters of unit outlet are coming up to the effluent permit limits from "Emission standard of pollutants for petroleum refining industry". The developed process is cost-effective because the operation costs as low as 0.54 CNY/t of wastewater treated. In conclusion, the successful experience could be copied to similar enterprises.

OPTIMIZATION AND COMPREHENSIVE UTILIZATION OF HYDROGEN RESOURCES IN PETROCHEMICAL ENTERPRISE

2021, 52(6):  108-111. 

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A part of hydrogen from propane/isobutane dehydrogenation unit is used for the unit own use, and the rest was only used as a supplementary fuel gas, resulting in a large waste of resources. The surplus hydrogen was optimized and comprehensively utilized as a hydrogen source for 2.4 Mt/a diesel hydroupgrading unit and 1.8 Mt/a gasoline hydrorefining unit, so it could avoid the secondary shutdown caused by the shutdown of the reforming unit and improve the continuity of the unit operation. Furthermore, the high purity hydrogen purified by PSA can replace the hydrogen used in polypropylene unit which is produced by hydrogen generator station, saving a lot of electricity cost every year. In addition, the gas seal of the product compressor（REC）of the dehydrogenation unit is changed from nitrogen to hydrogen of the reforming unit, which speeds up the start-up of the unit and avoids the waste of hydrogen and propane, and improves the economic benefit of the enterprise.

CASE STUDY OF THE EXHAUST GAS TREATMENT DURING SOIL REMEDIATION AT THE ORIGINAL SITES OF PETROCHEMICAL ENTERPRISES

2021, 52(6):  112-116. 

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Taking a petrochemical enterprise located in the north of China as an example, this paper analyzed the problem of the waste gas treatment in the process of on-site soil remediation. In the soil, benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, styrene, phenol, total petroleum hydrocarbons (C₁₀—C₄₀) and other pollutants exceeded the limits in national standard. In-situ multi-phase extraction, aeration technology and chemical oxidation technology were mainly used to treat the contaminated soil in the 4-14.5 m soil layer below the surface. In this process, it was necessary to ensure that the whole soil and groundwater pollution area was well sealed, and activated carbon was used to adsorb volatile organic compounds in tail gas. For the polluted soil 0-4 m below the surface, the exhaust gas from the membrane greenhouse was collected by the gas collector and then sent to the tail gas treatment device. The exhaust gas from the process of ectopic thermal desorption finally entered the two-stage activated carbon adsorption system, and the organic waste gas was absorbed by the activated carbon and then detected by the on-line monitoring device before emission.

DISCUSSION ON DEVELOPING HYDROGEN PRODUCTION USING VALLEY ELECTRICITY TO IMPROVE DEPLOYMENT CAPACITY OF RENEWABLE ENERGY

Zhao Xueliang

2021, 52(6):  117-120. 

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The necessity of hydrogen production by using valley electricity is introduced, and the economy is analyzed. The hydrogen generation unit can be used to adjust the power grid load according to the demand, to improve the deployment capacity of renewable energy, to guarantee the national energy security, and to effectively reduce carbon dioxide emission. The hydrogen can be used for hydrogen energy storage, fuel gas by injection of natural gas, oil product refining or steelmaking, and fuel cell vehicles, etc., which can bring economic benefits from hydrogen production using valley electricity. It is suggested that more efforts should be put to increase the research and development investment of low-cost and high-energy efficiency electrolyzer, to carry out the relevant research on pipeline hydrogen transportation, and to carry out the research on the application scheme of renewable energy hydrogen production in refining and chemical enterprises.