Table of Content

12 May 2022, Volume 53 Issue 5

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ANALYSIS ON IRON POISONING OF FCC CATALYST

2022, 53(5):  1-6. 

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In view of the serious iron poisoning of the catalysts in heavy oil catalytic cracking unit of a domestic refinery due to influence of processing heavy, inferior feedstock and bottom oil, the typical iron poisoning phenomenon in industrial production was analyzed from the property of equilibrium catalyst(E-cats) and products distribution, and the iron content of the E-cats was analyzed. The results showed that a high amount of iron pollution would decrease the bulk density of E-cats, and the correlation between iron content and the specific surface area and pore volume of E-cats was poor. It was found that the iron poisoning of catalyst could increase the yield of slurry and dry gas and decrease the yield of light oil, and that there were many depressions and grooves on the surface of the iron poisoning E-cats. The iron content in the depressions was relatively high, and the iron was mainly concentrated on the outer surface of the catalyst particles. Based on the above research results, some suggestions were provided for the device to process high-iron content feedstock. Among them, the use of a catalyst with better iron resistance can greatly solve the problem of iron poisoning.

EFFECT OF PREPARATION CONDITIONS ON CRYSTAL PHASE COMPOSITION OF COAL HYDROGENATION LIQUEFACTION CATALYST

2022, 53(5):  7-13. 

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Using FeSO₄.7H₂O as raw material, iron-based catalysts for coal hydrogenation liquefaction were prepared by precipitation-oxidation method under different conditions. The catalysts were characterized by XRD, SEM and N₂ absorption-desorption, and the effects of preparation temperature, preparation time and iron-coal mass ratio on the crystal phase composition, distribution and activity of the catalysts were investigated. The results showed that the crystallinity of α-FeOOH and γ-FeOOH was increased with the increase of preparation temperature, and further increased the preparation temperature, the crystal phase of the catalyst was transformed to γ-Fe₂O₃ with low activity. The crystallinity of α-FeOOH and γ-FeOOH crystal phases in the catalyst can be improved by increasing the preparation time, but a small amount of γ-Fe₂O₃ crystal phase will be generated by prolonged preparation time. Small iron-coal mass ratio is conducive to the formation of α-FeOOH and γ-FeOOH crystal phases, but the ratio too small, the crystallinity of α-FeOOH and γ-FeOOH will be decreased, and the ratio too large, γ-Fe₂O₃ will be formed.

STUDY ON NiO/Al₂O₃ CATALYST FOR SELECTIVE HYDROGENATION OF OLEFINS IN REFORMATE

2022, 53(5):  14-20. 

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The NiO/Al₂O₃ catalyst was prepared by equal volume impregnation using aluminum hydroxide dry glue as the raw material, and the catalytic performance of NiO/Al₂O₃ catalyst for selective hydrogenation of alkenes was investigated by using reformmate withthe bromine index of 3 836 mgBr/(100 g) as the raw material. The effects of carrier calcination temperature and NiO loading on the performance of NiO/Al₂O₃ catalysts were investigated. The results show that when the carrier calcination temperature is 650 ℃, and the catalyst with 25% NiO loading (w) is used, under the conditions of a reaction pressure of 1.0 MPa, a volume space velocity of 8 h^-1,a volume ratio of hydrogen to oil of 25:1 and a reaction temperature of 120 ℃, the oil bromine index is less than 100 mgBr/(100 g) , and the aromatics loss rate is less than 0.75%.

ACID MODULATION OF UiO-66-BASED CATALYSTS AND ITS APPLICATION IN THE DOUBLE-BOND ISOMERIZATION OF BUTENE

2022, 53(5):  21-27. 

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UiO-66-HCl and UiO-66-HAC catalysts containing defect sites were successfully synthesized by adding hydrochloric acid and acetic acid modifier. The results of XRD, TG, SEM, BET and TPD showed that the crystallinity, particle size, morphology and pore structure of the catalyst had been optimized, and the acid content has been increased. The evaluation results of butene as raw material showed that UiO-66 with many defect sites could significantly improve the catalytic performance of 2-butene double-bond isomerization to 1-butene. When the reaction temperature was 360 ℃ and the volume space velocity was 12 h^-1, UiO-66-HAC catalyzed double-bond isomerization of 2-butene to 1-butene with a yield of 12.7% and a selectivity of 97%.

PREPARATION OF HETEROATOMIC MESOPOROUS MOLECULAR SIEVE Ba-MCM-41 AND ITS ADSORPTIVE AND DENITRIFICATION PERFORMANCE

2022, 53(5):  28-35. 

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Mesoporous MCM-41 and Ba-MCM-41 molecular sieves were successfully prepared by hydrothermal synthesis and characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR) and nitrogen adsorption-desorption techniques. Ba-MCM-41 molecular sieve was used to remove nitrogen from simulated oil by static adsorption. The results showed that the best adsorption and denitrification effect was achieved when the molecular sieve dosage was 0.3 g, adsorption temperature was 30 ℃,adsorption time was 10 min and the simulated fuel dosage was 15 mL. The results of adsorption showed that the adsorption of pyridine and aniline on Ba-MCM-41 molecular sieve accorded with Freundlich isothermal adsorption, while that of quinoline accorded with Langmuir isothermal adsorption. The XRD spectra of MCM-41 molecular sieve constructed by Materials Studio software was identical to that of the samples prepared by the experiment. The adsorption energy of pyridine, aniline and quinoline molecules on Ba-MCM-41 molecular sieve and their distances from the active center of Ba-MCM-41 molecular sieve were calculated. The calculated results of the adsorption energies of three nitrogen compounds on Ba-MCM-41 were in agreement with the experimental results. The adsorption capacity of Ba-MCM-41 molecular sieve for pyridine and aniline was stronger than that for quinoline.

COMMERCIAL APPLICATION OF PHF-311 CATALYST FOR FCC FEEDSTOCK HYDROTRERATING

2022, 53(5):  36-39. 

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The hydrotreating catalyst PHF-311 developed by PetroChina Research Institute of Petrochemical Technology for FCC feedstock pretreatment was successfully applied in the 1.0 Mt/a gas oil hydrotreating unit of PetroChina Dushanzi Petrochemical Company in September 2019. The calibration results show that under the process conditions of a reaction temperature of 358.5 ℃ ,a reaction pressure of 10.9 MPa, a volume ratio of hydrogen to oil of 699, a space velocity for main agent of 0.94 h^-1, the gas oil with sulfur mass fraction of 493 μg/g and nitrogen mass fraction of 474.8 μg/g, and carbon residue of 0.15% can be obtained, which is a high-quality catalytic cracking feedstock. The hydrotreated diesel with 6.2 μg/g of sulfur and 30.8 μg/g of nitrogen can be used as diesel blending component. From the operation of the unit, it could be seen that PHF-311 catalyst had higher activities of hydrodesulfurization, hydrodenitrification and residue carbon reduction, which could meet the requirements of enterprises for clean fuel production.

MOLECULAR-BASED HYDROCARBON CONVERSION RULES IN FCC PROCESS

2022, 53(5):  40-46. 

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The conversion laws from feedstock to product on molecular level were studied based on the operation data from a commercial FCC unit, and the results of the apparent conversion of different hydrocarbons with aromatics formation and conversion were given. The results showed that comparing the compositions between feedstock and product, the paraffin hydrocarbon was increased by 31.47 percentage points, the naphthenic hydrocarbon was decreased by 23.21 percentage points, and the aromatic hydrocarbon was decreased by 17.47 percentage points. The mole ratio of product to feedstock was 5.92. The general apparent conversion was 80.77%, and the apparent conversions of paraffin, naphthenic and aromatic hydrocarbons were 91.99%, 96.62% and 66.10%, respectively. In cycloalkanes, the apparent conversions of monocyclic, dicyclic and tricyclic plus naphthenic hydrocarbons were 94.60%, 97.17% and 97.72%, respectively. In aromatics, the apparent conversions of monocyclic, dicyclic and tricyclic plus aromatic hydrocarbons were 86.60%, 19.64% and 68.56%, respectively. The proportions of monocyclic, dicyclic and tricyclic plus aromatic hydrocarbons in products by cracking the aromatic hydrocarbons with the corresponding aromatic ring number in feedstock were 13.4%, 38.8% and 86.1%, respectively, and the rests came from the aromatization or thickening of the feedstock or intermediate products.

STUDY ON FORMATION OF BENZENE FROM OLEFINS IN CATALYTIC CRACKING PROCESS

2022, 53(5):  47-52. 

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Using 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene as model compounds, formation of benzene from olefins was studied under different reaction temperature, different space velocity with different zeolite catalysts in a small fixed fluidized bed reactor. The reaction paths of olefins to benzene and the influence of reaction conditions on olefins to benzene were discussed. The results showed that cyclization of C6 chain olefin to form cycloalkene and then to form benzene was the main reaction path of benzene formation. Under conventional catalytic cracking conditions, the yield of five olefins to benzene on USY catalyst is low. The yield of benzene is increased with the increase of temperature or the decrease of space velocity. The yield of benzene over Beta catalyst and ZRP catalyst is higher than that of REY catalyst and USY catalyst when 1-decene as feed. In order to reduce the amount of benzene in the catalytic cracking products, the reaction temperature should be lowered as much as possible, the space velocity should be increased, and the reaction should be carried out on a catalyst with a large pore size and a low acid density, within the allowed conditions.

ANALYSIS OF CATALYST FLOW CHARACTERISTICS IN VERTICAL- INCLINED COMBINED STANDPIPE

2022, 53(5):  53-57. 

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A typical vertical-inclined combined standpipe with length of 3 600 mm and diameter of 80 mm was built to investigate the flow patterns of catalyst particles and their evolution under various mass flow rates. The flow patterns were identified by the distribution of the axial pressure and dynamic pressure. The results indicated that with the increase of the catalyst mass flow rate, the flow patterns of catalyst particles in the riser were changed from dilute to dense phase flow, and the axial pressure gradient was gradually decreased. When the catalyst mass flow rate was 720 kg/(m².s), the axial pressure was reversed with the filling flow at the bottom of the risers. The filling flow can be avoided by setting the aerating air. The main frequency range of different flow patterns is 0 - 0.5 Hz.

EXPLORATION AND PRACTICE OF TECHNICAL MEASURES FOR LONG-TERM OPERATION OF FIXED-BED RESIDUAE HYDROTREATING UNIT

2022, 53(5):  58-62. 

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The hydrogenation reaction characteristics of different types of raw residue are different. Compared with the residue with high sulfur content and low nitrogen content, the residual carbon precursor hydrogenation reaction of residue with low sulfur content and high nitrogen content is relatively difficult. The content of iron and calcium in feedstock, process conditions, reaction material distribution and the proportion of vacuum residue in feedstock affect the operation time of fixed-bed residue hydrotreating unit. In order to achieve a long operation cycle, the technical measures can be adopted as follows: Developing catalyst and catalyst grading technology suitable for different feedstocks, adopting high-efficiency distributor, increasing the hydrogen partial pressure of the unit and adding a reactor to reduce the volume space velocity, developing technologies related to guard reactors, selecting the appropriate proportion of vacuum residue according to the specific conditions of each plant and unit.

RESEARCH ON INTENSIFYING RESIDUE DEMETALIZATION BY ELECTRIC FIELD

2022, 53(5):  63-68. 

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The metal elements in residue mainly exist in polar components such as resin and asphaltene. Based on the electrification characteristics of the polar components, the method of applying electric field was proposed to enhance the demetalization of residue, so as to improve its properties and increase its comprehensive utilization value. The effects of mass ratio of solvent to oil, electric field intensity and electric field distribution on the removal of iron, calcium, nickel and vanadium in vacuum residue were investigated. The results show that increasing the solvent-oil ratio, increasing the electric field intensity and adopting reasonable electric field arrangement are beneficial to the removal of metal in residue. Under the action of electric field，the asphaltene rich in nickel and vanadium moves, accumulates and settles towards the wall of the tank, while the resins rich in iron and calcium moves and settles towards the electrode.

INDUSTRIAL PRACTICE OF DIRECT PRODUCTION OF MIXED C₅ OLEFIN IN DEEP CATALYTIC CRACKING (DCC) UNIT

2022, 53(5):  69-73. 

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In view of the problem of unqualified C₅ product quality and low output in the In order to solve the problems of unqualified C5 products and low output in the early stage of the start-up of deep catalytic cracking(DCC) unit, a series of measures were taken, such as revamping the extraction position of C₅ products in the light and heavy gasoline separation column, optimizing and adjusting the operation parameters, etc. The results showed that the purity of C₅ was increased to 93.64% from 78.4%, and the output was increased to 12 t/h from 1.5 t/h. Not only the goal of qualified product quality and increased production was achieved by these measures, but also the smooth operation of the downstream naphtha hydrogenation unit was ensured. It is the first time to directly produce mixed C₅ olefins in DCC unit. The annual economic benefit is more than 40 million yuan.

DETERMINATION OF HYDROCARBON TYPES OF PYROLYSIS OIL FROM WASTE PLASTICS

2022, 53(5):  74-78. 

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A pretreatment method of solid phase extraction for pyrolysis oil from waste plastic was developed. The pyrolysis oil was separated into saturates, olefins and aromatics by double solid phase extraction column which was made up of silica gel and silver-aluminium oxide, and then they were analyzed by GC-MS-FID, respectively. According to the relationship of boiling points and retention time, the obtained gas chromatogram and total ion chromatogram (TIC) of the compounds were divided to diesel and vacuum gas oil (VGO) distillates, and the hydrocarbon compositions of diesel and VGO fractions were obtained by combining gas chromatogram and mass spectra. The hydrocarbon composition of diesel oil and VGO fraction in pyrolysis oil with wide boiling point were analyzed.

QUANTITATIVE CORRELATION ANALYSIS OF RESIN AND ASPHALTENE IN RESIDUE

2022, 53(5):  79-82. 

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The correlation of resin content and asphaltene content with carbon residue, (Ni + V) content, sulfur content and nitrogen content was obtained by multiple regression method. The results showed that there was a good quantitative relationship between asphaltene content and carbon residue value, (Ni + V) content, and there was an obvious quantitative relationship between resin content and carbon residue value, nitrogen content. The correlation coefficient of resin content and asphaltene content is higher than 0.9, which is similar to that obtained by RIPP 10-1990 “determination of four components of heavy oil by alumina adsorption”.

PRODUCTION DATA PROCESSING ALGORITHM OF SMART REFINERY AND ITS APPLICATION IN CATALYTIC REFORMING DATA PROCESSING

2022, 53(5):  83-87. 

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The production data is the data with the widest source, longest-span, and largest-scale in modern refineries. It is of great significance for optimizing production, improving quality and efficiency, and building smart refinery to fully handle and make good use of production big data. The general standard process software package SmartPec was specially designed for processing the production data of the smart refinery, and its application in catalytic reforming data processing were introduced. The mean square error of the generalized linear model was reduced by 76.9% and the mean square error of the neural network model was reduced by 88.3% by data pre-processing and categorical modeling. Four key factors affecting the yield of reforming aromatics were identified accurately, and the scheme of maximizing the yield of reforming aromatics was provided. The results show that SmartPec can greatly improve the accuracy of data modeling and prediction of catalytic reforming and various units in refinery plants, with a wide range of applications and strong versatility; it can be used to detect differential features between multiple types of samples, with flexible application mode and strong stability; it can be used for a variety of optimization tasks, easy to use, convenient and fast.

DEVELOPMENT AND COMMERCIAL APPLICATION OF AN OPTIMIZATION MODEL OF OCTANE NUMBER FOR REFINED GASOLINE FROM S Zorb UNIT

2022, 53(5):  88-94. 

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Aiming at the large loss problem of research octane number (RON) of refined gasoline from S Zorb unit, based on the historical data from a S Zorb unit in the past 3 years, the maximal information coefficient (MIC) and Pearson correlation coefficient were used in combination with BP neural network, 22 modeling variables were selected from 273 variables including feed oil properties, adsorbent properties, product properties and operation variables, and a RON prediction model with the structure of 21-14-1 was established and validated. The results show that the prediction model has good goodness of fit and generalization ability, and its average absolute error and determination coefficient (R²) of the model on the test set are 0.116 3 and 0.960 1, respectively. On this basis, genetic algorithm (GA) was used to optimize the best operation variables to improve the product RON. It was found that the model could effectively reduce RON loss of gasoline through optimization, and the RON loss of gasoline could be reduced by 25% through the optimization model.

OPTIMIZATION AND APPLICATION OF VISCOSITY BLENDING MODEL FOR LUBE BASE OIL

2022, 53(5):  95-102. 

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The accuracy and applicability of the mathematical model for viscosity blending of synthetic lubricant base oils (referred to as base oils),sourced from natural gas,with blends of other three base oils were investigated. The kinematic viscosities of the blends of synthetic base oil GTL420 with synthetic base oil PAO10, mineral base oil 500N and coal-based Fischer-Tropsch synthetic base oil CTL10 in different proportions at 40 ℃ and 100 ℃ were measured, and the viscosity blending model was optimized. The models were evaluated based on the deviation rate, root mean square error, sum of squared residuals, and correlation coefficient. The results show that the Arrhenius equation has the largest deviation rate among the three blending systems and cannot accurately describe the true kinematic viscosity of the blended base oil; the Lederer-Roegiers Sr equation and the Grunberg-Nissan equation exhibit similar simulation effects, but have different validity in different blending systems; the Oswal-Desai equation has a complex structure, but its accuracy and applicability are optimal.

EFFECT OF HYDROPHOBIC CALCIUM BORATE NANO-ADDITIVE ON TRIBOLOGICAL PERFORMANCE OF RAPESEED OIL

2022, 53(5):  103-108. 

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The surface of calcium borate was modified by stearic acid, oleic acid, ethylenediaminetetraacetic acid and polyethylene glycol, respectively.Various nanometer calcium borate lubricant additives with different hydrophobicity were prepared, and the effect of the modified calcium borate nano-additives on the antiwear and friction-reducing performance of rapeseed oil was systematically investigated by means of SEM, FTIR and tribological test. The results show that the stearic acid-modified calcium borate has the best hydrophobicity, the oleic acid-modified calcium borate has the second hydrophobicity, and ethylenediaminetetraacetic acid modified calcium borate still was hydrophilic, but the calcium borate had not been chemically modified by the polyethylene glycol. It is found that the calcium borate modified with stearic acid shows the best anti-wear and friction-reducing performance in rapeseed oil. When the dosage of calcium borate modified with stearic acid in rapeseed oil was 0.5%, the friction coefficient and the wear scar diameter of the test steel ball were decreased by 22% and 24% than that of rapeseed oil base oil, respectively.

STUDY ON CARBON EMISSIONS AND CARBON EMISSION REDUCTION CURVE OF CHINA’S REFINING INDUSTRY

2022, 53(5):  109-114. 

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In order to achieve the “Double carbon” goal of carbon peak and carbon neutrality, more stringent requirements were put forward for energy saving, green and low-carbon development in China’s refining industry. Based on the 2019 actual data of 40 integrations of refinery and petrochemical enterprises in China, the carbon emission of China’s refining industry was obtained through research and calculation, and the characteristics of various carbon reduction methods were specifically analyzed. The carbon emission reduction potential of each method was calculated quantitatively, and the carbon emissions reduction curve was drawn according to the results of the analysis, which provided a decision-making reference for China’s refining industry to achieve “Double carbon” targets.

STRESS RESPONSE MECHANISM OF OIL-DEGRADING BACTERIA ZS1 TO TOXIC EFFECT OF TYPICAL ANTIBIOTICS

2022, 53(5):  115-122. 

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In order to elucidate the ecological effects of antibiotics on oil-degrading bacteria and the stress response mechanisms of microorganisms to the toxic effects of typical antibiotics, toxicity tests of different concentrations of typical antibiotics on oil-degrading bacteria pseudomonas aeruginosa (ZS1) were carried out, and the growth and toxicity of thallus cells treated with three kinds of antibiotics (Oxytetracycline, Erythromycin and Sulfadiazine) were studied. The results showed that three antibiotics had different bacteriostatic effects on ZS1, among which Oxytetracycline had the strongest inhibitory effect on ZS1 activity, and the inhibition rate was increased obviously with increasing Oxytetracycline concentration, and there was a significant concentration-effect relationship. The mechanism of ZS1 antioxidant enzymes (Catalase, Peroxidase and Superoxide dismutase) in response to antibiotics was investigated. The results showed that ZS1 could resist external pollution and maintain cellular function by producing antioxidant enzymes when it was contaminated.