Table of Content

12 January 2019, Volume 50 Issue 1

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EFFECT OF ZEOLITE ON HYDRODESULFURIZATION PERFORMANCE OF CoMoP/Al2O3 CATALYST

2019, 50(1):  1-7. 

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CoMoP/Al2O3-Y catalysts with USY zeolite as an acidic component were prepared. The samples were characterized by N2 adsorption-desorption, pyridine-FTIR, X-ray photoelectron spectra (XPS) and high-resolution transmission electron microscopy (HRTEM) techniques. The hydrodesulfurization performance of 4, 6-dimethyldibenzothiophene was evaluated over CoMoP/Al2O3-Y catalyst in a high pressure fixed-bed reactor. The results showed that compared with CoMoP/Al2O3, the introduction of USY zeolite significantly improves the conversion and S-removal rate, and changes the HDS product distribution. The transalkylation and cracking activities of CoMoP/Al2O3-Y catalyst increase substantially, the direct desulfurization activity is comparable in activity, however, the activity of hydrogenation route decreases over CoMoP/Al2O3-Y catalyst.

CATALYTIC CRACKING OF n-DECANE TO C4 HYDROCARBONS ON DIFFERENT ACIDITY Y ZEOLITE CATALYSTS

2019, 50(1):  8-12. 

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The USY, REHY, REY zeolite containing catalysts were prepared by spray drying. The effects of reaction temperature, agent oil mass ratio and catalyst acid content on the production of C4 hydrocarbons were investigated by catalytic cracking of n-decane in a small fluidized bed. At the reaction conditions of catalyst/oil mass ratio of 6, reaction time 75s, the selectivity of isobutane decreases by 2 %, while the selectivities of n-butane and isobutene increase of 1%, but the selectivity of n-butene increases of 2-3% as the reaction temperature increases from 460℃ to 540 ℃. The selectivity of C4 hydrocarbon products is basically unchanged at reaction temperature of 500℃ in the range of catalyst/oil mass ratio from 3 to 9. Increasing the acid content of catalyst can increase the selectivity of n-butane and isobutane and decrease the selectivity of butene and isobutene.

EFFECT OF ADDING MOLECULAR SIEVE ON HYDRODENITROGENATION ACTIVITY OF Ni-Mo/Al2O3 CATALYST

2019, 50(1):  13-19. 

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The carriers were prepared by beating and modeling SAPO-5, Beta, Y molecular sieves and pseudo-boehmite, respectively. The hydrodenitrogenation (HDN) catalysts were prepared by loading Ni-Mo metal components on the prepared carriers. The influence of different types of molecular sieves adding into alumina carrier on catalyst acidity, metal morphology and HDN performance were investigated. The characterization results of NH3-TPR, Py-IR, H2-TPR, HR-TEM indicated that compared with pure alumina carrier catalysts, the introduction of molecular sieve increases catalysts acidity amount and strength, modifies carrier surface property, decreasing MoS2 lamella length but increasing stacked layers number. Different types of molecular sieves have different impacts on the catalysts acidity and metal morphology. The evaluation results of HDN of coke gasoil illustrated that introducing molecular sieves into alumina carrier improves the HDN activity of catalysts; the catalysts with high hydrogenation activity have a higher selectivity to non-basic nitrogen removal, while the catalysts with high hydrogenolysis activity have a higher selectivity to basic nitrogen removal.

COMPARISON OF ECONOMIC BENEFITS OF CONTINUOUS REFORMING CATALYST REPLACEMENT CYCLES

2019, 50(1):  20-24. 

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The replacement of CCR catalyst is an important process for refineries. Based on the data in two cycles of 1.0 MMt/a CCR unit of Jinling branch, SINOPEC, the economic benefits of the device under the replacement of a new catalyst in 1 cycle (4 years) and 2 cycle (8 years) were comprehensively analyzed from catalyst cost, fuel gas consumption, and product yield. The results show that the economic benefit of replacing new catalysts in one production cycle is 19.87 million Yuan /a higher than that in two production cycles. Replacing a new catalyst with one production cycle is more economical and can also reduce the number of unscheduled shutdown due to corrosion.

STUDY ON Pt/Hβ HYDROISOMERIZATION CATALYST AND ITS REDUCTION CONDITIONS

2019, 50(1):  25-30. 

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The Pt/Hβ isomerization catalysts were prepared by using Hβ zeolite with different silica-alumina ratio as the carrier and loaded with Pt. The Pt/Hβ catalysts were characterized by N2 adsorption-desorption，XRD，NH3-TPD，Py-IR and TEM. And the isomerization performance of the prepared catalysts was evaluated in a 10 mL fixed-bed micro-reactor. The results showed that the silica-alumina ratio of Hβ zeolite has a significant effect on the acidity and pore structure of the catalyst. With the increase of silica-alumina ratio，while the total acid，medium strong acid and Br?nsted acid sites, and the specific surface area and pore volume decrease，which improve the conversion rate of n-hexane and inhibit the isomerization and dimethylbutane selectivity. The Pt/Hβ catalyst with silica-alumina ratio of 25 has the best isomerization performance. Reduction temperature and pressure mainly affects the size and distribution of Pt on the catalyst. At reduction temperature of 350 ℃ and 0.75 MPa，the average particle size of Pt is the smallest and uniformly distributed，which is beneficial to improve the metallicity and acid matching degree of the catalysts，and the best isomerization results is 81.16% n-hexane conversion rate，82.89% isomerization rate，25.58% dimethylbutane selectivity.

EFFECT OF PROCESS CONDITIONS ON PERFORMANCE OF FISCHER-TROPSCH WAX HYDROCRACKING CATALYST

2019, 50(1):  31-36. 

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The hydrocracking catalysts were prepared by loading Ni-W onto USY-Al2O3 carrier through incipience wetness impregnation method and characterized by X-ray diffraction，infrared diffuse reflectance Pyridine adsorption and low temperature nitrogen adsorption desorption techniques. The effects of temperature, space velocity, hydrogen-oil ratio, and pressure on the hydrocracking performance of Fischer-Tropsch waxes were investigated by the single-factor variable method. The results showed that the influence of operating conditions changes as orders: temperature> space velocity> hydrogen oil volume ratio> pressure. At the optimized conditions of 340°C, 4 MPa, Sv 1.5h-1, hydrogen to oil ratio 1 000(v), the conversion is the best. The conversion rate of heavy wax oil is as high as 98.11%, light oil yield reaches 93.5%, and the yield of cracked gas is only 6.5%.

DEVELOPMENT AND INDUSTRIAL APPLICATION OF SOLVENT EXTRACTION- SELECTIVE HYDRODESULFURIZATION COMBINATION TECHNOLOGY

2019, 50(1):  37-41. 

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Aiming at the problem of large RON loss in the production of national Ⅴ standard gasoline from the catalytic cracking gasoline feed with high sulfur content，high olefin content and low aromatic content，solvent extraction and selective hydrodesulfurization combined technology（Referred to as RCDS technology） was developed. The results of the pilot test show that the RON loss is reduced by 0.9—1.9 units when using RCDS technology to process the catalytic cracking gasoline with the above characteristics producing national V standard gasoline compared with the selective hydrodesulfurization technology. Industrial application results show that using this technology to process Qingjiang catalytic cracking gasoline with sulfur mass fraction of 418—460 μg/g, olefin volume fraction of 27.6%—27.9%, and aromatic volume fraction of 19.2%—19.3%，When the product sulfur content is reduced to 7 μg/g，the gasoline RON loss is only 1.0—1.3 units，and the gasoline（C5+）yield is as high as 99.9%.

PRACTICE AND ANALYSIS OF FCCU EFFICIENT OPERATION BASED ON SYNERGY OF REFINERY

2019, 50(1):  42-46. 

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Based on analysis of refinery total process, the whole strategy of FCCU efficient operation was discussed. By the separated storage and separated process of crude oil and the coordinated operation of CDU-delayed coking-hydrotreating of VGO, the < 350℃ diesel fraction in FCC feed can be reduced. The FCCU operation with high efficient was realized by increasing operation load of solvent deasphaltene and VGO hydrotreating–distillation process, as well as residue blending in FCC feed. Besides, HCO and LCO after hydrotreating can be converted to gasoline, thus the diesel/gasoline ratio is reduced based on the load of reforming and H2 PSA operation. At the same time, the coking unit operates under low load and obtains new function through the recycling of light hydrocarbon and heavy oil.

PRACTICE OF VGO HYDROGENATION UNIT USED AS LTAG HYDROGENATION UNIT

2019, 50(1):  47-52. 

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The 1.8 Mt/a VGO hydrotreating unit was modified and used as a LTAG hydrotreating unit in SINOPEC Maoming Company. The modification effect and the problems and solutions during the operation were introduced. The industrial operation results indicated that by using the new generation catalyst system developed by RIPP，under the conditions of lower reaction temperature and hydrogen partial pressure，low sulfur and low nitrogen refining wax oil can be produced (sulfur 0.1% and nitrogen 560 μg/g). After mixing 35 t/h (about 14% of the total feed) catalytic cracking diesel, the hydrogenated diesel with a high content of monocyclic aromatic hydrocarbons and a mass fraction of polycyclic aromatic hydrocarbons less than 15% can be produced and used as LTAG process feed. The composite catalysts exhibit good activity and excellent comprehensive performance. When the feedstock is composed of mixture of LCO and VGO， the inlet temperature and average temperature of the reactor are decreased，while the reactor temperature and hydrogen consumption increased，and the comprehensive energy consumption is similar to that of pure VGO feed. During the start-up of the device, problems such as too many light fractions, large fluctuation of the fractionation system, and insufficient liquid in cold high pressure separator were encountered, leading the inability to further improve the process capacity. These problems were solved by taking measures to ensure the normal production of the plant.

UTILIZATION OF PHENOLIC COMPOUNDS IN LIGHT FRACTION OF FUSHUN SHALE OIL

2019, 50(1):  53-57. 

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The removal of phenolic compounds(P) in the Fushun shale oil (<280 ℃) was studied by using oxalic acid as catalyst and formaldehyde(F) as reaction reagent. The effects of mass ratio of phenol to formaldehyde, the ratio of m (P)/m (F)), catalyst dosage, condensation reaction time and temperature on the softening point and the dissolved viscosity of produced resin were investigated. The fourier transform infrared spectroscopy (FT-IR) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) were applied to analyze the phenolic resin. The results showed that at the conditions of the m(P)/m(F) =1:0.87, the catalyst dosage of 2%, the condensation reaction time of 6 h and the reaction temperature of 95 ℃, the removal efficiency of phenolic compounds reaches 87.94%. The dissolved viscosity of the resin is 63 mPa?s, with the softening point of 94 ℃, meeting the GB/T 30772-2014 requirements.

SUMMARY OF PRODUCTION AND OPERATION OF C5/C6 LOW TEMPERATURE ISOMERIZATION UNIT

2019, 50(1):  58-62. 

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UOP Penex-DIH low temperature isomerization technology was first adopted in 300 kt/a C5/C6 isomerization unit of SINOPEC Tahe Company to produce the gasoline blending component with RON≥85 using the C5/C6 light naphtha at the top of the pre-distillation column as raw material. This paper mainly summarizes the composition of raw oil and its impurities, operating conditions, properties of isomerized products, material balance and energy consumption of the unit from 2015 to 2018, and analyzes the existing problems in the operation, and puts forward suggestions for improvement and optimization.

ANALYSIS OF DILUTE DENSITY ABNORMITY IN FCC REGENERATOR AND MEASURES

2019, 50(1):  63-68. 

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It was found that the dilute phase density of regenerator of FCCU rising abnormally, regenerator capacity reduction, and the bigger fine size in flue gas at outlet of three stage cyclones in Zhenhai refining branch. By analysis of Fe content on equilibrium catalyst and electron microscope scanning method, it recognized that the iron poisoning is the reason for these phenomena. Through taking measures: reducing the iron content in feed, increasing the rate of adding fresh catalyst, using low magnetic agent replacement, reducing the main air volume, the normal operation conditions were quickly achieved. The source of iron, symptoms of iron poisoning and the measures to deal with iron poisoning were further analyzed.

STUDY OF PROCESSING FISCHER-TROPSCH WAXES BY VACUUM DISTILLATION AND EXTRACTION REFINING

2019, 50(1):  69-72. 

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This paper introduced a method of refining Inner Mongolia Itai Fischer-Tropsch waxes to reduce oil content. The method removed iso-hydrocarbons and oxygenate by combining process of vacuum distillation and solvent extraction. The effects of the extraction agent, the conditions of extraction on the removal efficiency were investigated. The Fourier transform infrared spectroscopy (FT-IR) and High temperature gas chromatography simulated distillation were applied to analyze the Fischer-Tropsch waxes. The results showed that the yield of Fischer-Tropsch waxes and oil content can reach 93.75% and 0.97‰, respectively by using N-methyl pyrrolidone as solvent, extraction temperature of 120℃, catalyst/oil ratio of 2:1. At this point, the refined wax has a melting point of 112°C and a penetration of 0.1mm. The product satisfies the quality standard of H105 Fischer-Tropsch wax produced by Sasol. The carbon number of refined F-T waxes is distributed between C19 and C120, and FT-IR characterization showed that it is simple in structure, mainly composed of long chain n-alkanes, among which the content of C35 is the highest.

NUMERICAL SIMULATION AND STRUCTURE OPTIMIZATION OF UOC TYPE QUENCH BOX

2019, 50(1):  73-80. 

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Based on literature experimental data, the numerical model validation was performed and the accuracy of the selected numerical model was verified. Based on industrial operating conditions, Fluent software was used to simulate the hydrodynamic performance of UOC quench box. The structure optimization of the spacing of contractive-type flow passages and the distance between the screen hole baffle and the square box was conducted. In addition, the baffle was added at the exit of contractive-type flow passage. The results showed that the performance of the optimized quench box is better than that of the basic configuration. The temperature distribution unevenness is reduced by 36.8% and the pressure drop is reduced by 21 Pa. The comprehensive performance of the quench box is greatly improved.

STUDY ON VISCOSITY INDEX PREDICTION OF VGO BY NEAR INFRARED SPECTROSCOPY

2019, 50(1):  81-84. 

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To obtain the viscosity index of VGO rapidly, a prediction model was established by random forest regression algorithm, based on the near infrared spectroscopy and viscosity index data of 70 representative VGO samples. Based on the importance measurement of each feature in the random forest algorithm, the recursive feature elimination method was used to select wavelength variables in NIR. The more robust model was built by selecting 10 characteristic wavelengths as the input features for the model and determining the hyper parameters (the number of trees in the forest nt of 150, the number of features to consider when splitting nv of 5) by 10-fold cross validation. The prediction standard deviation of 7 new samples is 2.28 with R2 of 0.98, indicating high accuracy and strong generalization ability of this model.

DETERMINATION OF BROMINE NUMBER OF MID-LOW TEMPERATURE COAL TAR BY ALKALI WASH PRETREATMENT

2019, 50(1):  85-88. 

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An alkali pre-washing for determination of bromine number of mid-low temperature coal tar was established, by which the interference of phenols in the coal tar on bromine number could be avoided. The influence of phenols on the determination of bromine number was investigated and determined by model compounds. The phenolic and olefin model compounds were used to investigate the phenol removal rate and the standard recovery, respectively. The removal of phenols reaches 100% by the alkali pre-washing method. For actual samples this rate is greater than 97.0%. The standard addition recovery is greater than 96.8% and the relative standard deviation is less than 2.0%. The oil phase and water phase cross little after pretreatment.

PROPERTIES ANALYSIS OF RESIDUE FROM COAL-OIL CO-PROCESSING

2019, 50(1):  89-95. 

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The composition, microstructure and functional groups of coal-oil co-processing residue were analyzed by elemental analysis, industrial analysis, thermogravimetry, X ray diffraction, scanning electron microscopy and infrared spectroscopy. The content of functional groups was semi-quantitatively calculated by the peak fitting of infrared spectroscopy. The results showed that the organic matter of the residue are composed of lamellar stacking carbon particles, the inorganic matter of residue are composed of coal-oil co-processing catalyst fines and inorganic minerals in coal. The diameters of the residue particles are distributed in around 10 μm and 2 μm. The particles distribute disorderly in integer area and orderly in local area. Volatile, fixed carbon and ash contents were determined by industrial analysis; the results are close to that of thermogravimetric analysis. The hydroxyl self-associating groups in the hydrogen-bond in the residue account for 47.9%, the methylene groups of the aliphatic-hydrogen account for 64%. The oxygen-containing functional groups exist in the form of carbon oxygen bonds and carbonyl groups mainly, and contained tiny silicon oxygen bonds, but without carboxyl group. The aromatic groups contain more alkyl-side-chain substituents, while the aromatic groups with five substituted hydrogen account for only 4.5%.

APPLICATION OF RDNOx ADDITIVE TO MEET EMISSION REGULATIONS OF NOx IN FLUE GAS

2019, 50(1):  96-100. 

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The DCC unit in SINOPEC Anqing Company is lack of NOx reduction equipment. To meet the requirement of NOx emission regulations，a commercial trail of RDNOx additive was conducted. The results showed that, when additive was accumulated to about 2.5% of catalyst inventory and added by 0.03 kg/t (based on fresh feed) without strict controlling of excess O2, NOx in flue gas could be decreased to 70 mg/m3, which meets the requirements of the latest national regulations. Nowadays, the addition of RDNOx is adjusted to 0.015 kg/t (about 1.5% of fresh catalyst); NOx in flue gas is still lower than the limitation. Compared with the 400~500 mg/m3 NOx emissions before adding the additive, NOx is decreased by over 80%. In addition, the application of RDNOx additive has little influence on product distribution and properties.

ELIMINATION OF BLUE SMOKE PLUME FROM FCC REGENERATOR WITH SULFUR TRANSFER ADDITIVE

2019, 50(1):  101-104. 

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To treat the blue smoke plume of FCCU of CNOOC Huizhou Petrochemicals Company, the RFS sulfur transfer additive were used according to the properties of FCCU and smoke. The changes of sulfur distribution, SOx concentration, soot concentration, alkali quantity and dissolved solids content before and after the addition of sulfur transfer additive as well as the economic accounting were compared. The results showed that the sulfur transfer additive can effectively reduce SOx content in flue gas at inlet of scrubber in 18 hours and the blue smoke of the outlet gas is gradually eliminated. Most of the sulfur is transferred into dry gas, and the sulfur content in LPG and acidic water is decreased. When the sulfur transfer additive in the catalyst inventory reaches 2.56%, much lower sulfur content in flue gas at outlet of scrubber can be obtained, SO2 concentration is below 50 mg/m3, SO3 concentration is less than 20 mg/m3, alkali consumption for wet desulfurization is reduced by 90%, and reduction of soluble solids in the effluent waste water is 86.3%, and the effluent gas smoke concentration decreases by 64.3%, the operation cost is reduced by 1.3437 million Yuan/a.

EVALUATION METHOD AND APPLICATION OF CORROSION INHIBITOR IN CRUDE DISTILLATION UNIT OVERHEAD SYSTEM

2019, 50(1):  105-109. 

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A set of evaluation method for inhibitors selection used in crude distillation unit overhead system was established. Based on the other relevant standards, the methods include: (i) weight loss method (static) to evaluate the inhibition efficiency of inhibitors; (ii) evaluation of film forming performance of inhibitors with saturated sulfate copper solution; (iii) evaluation of emulsification tendency of the inhibitor based on the stability of the emulsion; (iv) dissolution or dispersion properties of inhibitors in oils and waters using water and naphtha as solvents. The inhibitor with 4 best results is the suitable inhibitor. Five inhibitors were screened by the evaluation method. EPR81 has the best performance and is proven by the field application. This indicates that the evaluation method is accurate and effective.