Table of Content

12 April 2020, Volume 51 Issue 4

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HYDRODESULFURIZATION PERFORMANCE OF 4, 6-DIMETHYLDIBENZOTHIOPHENE OVER CATALYSTS CONTAINING HIERARCHICAL ZEOLITES

2020, 51(4):  1-6. 

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CoMoP catalysts containing zeolites were prepared by saturated impregnation using hierarchical Y zeolites as acidic components. The zeolite samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, high-resolution transmission electron microscopy (HRTEM) and pyridine-FTIR techniques. The HDS performance of CoMoP catalysts containing hierarchical Y zeolites was evaluated in a high pressure micro-reactor using 4, 6-dimethyldibenzothiophene as a model compound. The results showed that the high external surface area and mesoporous volume of hierarchical Y zeolites contributed to higher accessibility of Br?nsted acid sites. Compared with the reference CoMoP/Al2O3-Y catalyst, the catalysts containing hierarchical Y zeolites with high Bronsted acidity exhibited acid-catalyzed reaction activity and higher total HDS activity. The transalkylation activity was increased with the strong Br?nsted acidity of zeolite.

COMMERCIAL APPLICATION OF CATALYTIC CRACKING CATALYST FOR INCREASING BUTYLENE SELECTIVITY

2020, 51(4):  7-12. 

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Based on the differences of catalytic materials on the cracking performance of heavy oil and the selectivity of butylene, a catalytic cracking catalyst HBC was developed to selectively increase the yield of the target product and has been applied in No.3 FCC unit of SINOPEC Shijiazhuang Refining and Chemical Company. The results showed that the butylene yields were increased by 0.52-0.82 percentage points, the mass fractions of butylene in LPG were increased by 1.90-3.09 percentage points, the gasoline yields were increased by 0.44-1.74 percentage points, the total liquid yields were increased, and the coke selectivity improved. HBC catalyst provides excellent butylene selectivity and heavy oil cracking capacity simultaneously.

INDUSTRIAL APPLICATION OF FPD-5 type CO COMBUSTION-DENITRATION AGENT IN CATALYTIC CRACKING UNIT

2020, 51(4):  13-17. 

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The industrial application results of CO combustion-denitration agent FPd-5 in a catalytic cracking unit of a refinery of SINOPEC against the previously-used combustion promoter was introduced. The results showed that FPd-5 agent exhibits the close results in terms of product distribution and properties to the previous promoter under the same dosage and process operation conditions. While the NOx content of regenerated flue gas was 93 mg/m3 using FPd-5，lower than the value of 200 mg/m3 required by the national standard GB 31570—2015 . At the same time，no tail-burning phenomenon was found.

STUDY ON SYNTHESIS OF MESOPOROUS ACTIVATED CLAY AND ITS CATALYTIC PERFORMANCE FOR 1-PROPANETHIOL OXIDAION

2020, 51(4):  18-23. 

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In this paper, agglomerated bulk activated clay was used as precursor, which was stripped and dispersed under basic conditions, and then the short-range ordered mesoporous SiO2 was introduced into the activated clay interlayers by the guiding of cetyltrimethylammonium bromide (CTAB) to obtain the flake mesoporous activated clay. The as synthesized mesoporous activated clay and the reference activated clay were subjected to copper ion (Cu2+) modification by equal volume impregnation method. The static catalytic oxidation experiment with 1-propanethiol hexane solution showed that the conversion of 1-propanethiol on Cu2+modified clay was close to 100% when the copper loading was 25% (w) and the activation temperature was 150 °C. Dynamic catalytic oxidation experiment showed that the mesoporous activated clay had higher Cu2+ loading capacity and exhibited better catalytic oxidation performance for thiol under the same Cu2+ loading. In addition, the study on catalytic oxidation mechanism of 1-propanethiol found that the excessive 1-propanethiol was catalyzed by Cu2+ to form dipropyl disulfide.

STUDY ON SYNTHESIS TECHNOLOGY OF LONG CHAIN ALKYLBENZENE SULFONATE

2020, 51(4):  24-27. 

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Olefin and aromatic were used as raw material to prepare long chain alkylbenzene sulfonate by alkylation, sulfonation, and neutralization reactions. The effect of amount of the catalyst, adding velocity of promoter and the mole ratio of olefin to aromatic on the yield of alkylation reaction were investigated．The effects of the mass ratio of oil to acid and adding speed of acid on the interface performance were investigated. The optimum conditions for synthesis of long chain alkylbenzene sulfonate were determined. The interface performance of the long chain alkylbenzene sulfonate synthesized is superior to the petroleum sulfonate and heavy alkylbenzene sulfonate.

EFFECTS OF WATER ON CATALYST PERFORMANCE FOR TOLUENE DISPROPORTIONATION AND TRANSALKYLATION

2020, 51(4):  28-32. 

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Toluene disproportionation and transalkylation reactions play an important role in the adjustment of aromatic resources and the reuse of inferior resources. The water content in feed affects the reactions significantly, however, it depends upon the upstream device and downstream storage environment with a large fluctuation range. The effect of water content on toluene disproportionation and transalkylation reaction was studied by using Ni modified zeolite catalyst. The results showed that within the testing range [w(H2O)<200 μg/g], the content of water had little influence on toluene disproportionation and transalkylation reaction of toluene and heavy aromatics. However, the water in the raw materials could reduce the metal reduction degree of the Ni hydrogenation active center, thereby reducing the hydrogenation activity of the catalyst and inhibiting the hydrodealkylation reaction of the side chain of heavy aromatics, thus reducing the processing capacity and overall conversion efficiency of the heavy aromatics. The inhibited hydrogenation activity would also reduce the hydrogenation of aromatic ring, so as to improve the quality of benzene product.

APPLICATION OF EBULLATED BED HYDROGENATION TECHNOLOGY IN HYDROUPGRADING OIL FROM COAL DIRECT LIQUEFACTION

2020, 51(4):  33-36. 

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Ebullated bed hydrogenation technology was adopted to solve the difficulty in hydrogenation of oil from coal direct liquefaction because of its high content of resin and asphaltene and solid impurities. The industrial results showed that the qualities of hydrogenation stabilized oil meets the design requirements, even though the actual raw material was significant heavier than the design one. The sulfur and nitrogen contents of heavy oil from coal direct liquefaction were greatly reduced, and the effect of resin removal was obvious. The aromatic carbon ratio decreased from 55.86% to 38.30%, a decrease of 17.56 percentage points, which conforms the design requirements for the aromatics saturation depth of the device. The practice results also prove that the domestic catalyst shows the better performance than the imported catalyst in activity and long-run stability and that the ebullated bed hydrogenation technology can solve the problem in hydrogenation of oil from coal direct liquefaction .

REMOVAL OF NITROGEN COMPOUNDS FROM SIMULATED OIL WITH CH3COOH/ZnCl2 DEEP EUTECTIC SOLVENT

2020, 51(4):  37-42. 

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The CH3COOH-ZnCl2 deep eutectic solvent(DES) was prepared using mixed glacial acetic acid (CH3COOH) and zinc chloride (ZnCl2) by heating and analyzed by Fourier transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance (1H NMR) analysis. The denitrogenation performance was characterized using octane solution spiked with quinoline or indole as simulated oils. The results showed that the removal rates of quinoline and indole were 98.57% and 93.73%, respectively, when the molar ratio of CH3COOH to ZnCl2 was 10:1, the extraction time was 25 min, the mass ratio of simulated oil to DES is 5:1, and the extraction temperature was 30 ℃. After three times recoveries for DES，the denitrogenation rate of the quinoline simulated oil or the indole simulated oil can still reach 70% or more, respectively. In addition，the mechanism of nitrogen removal during denitrogenation by extraction were discussed.

NEGATIVE EFFECT OF HEAT STABLE SALT IN ALKANOLAMINE SOLUTION ON DESULFURIZATION PLANT AND ITS REMOVAL PROCESS

2020, 51(4):  43-49. 

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The types of heat stable salts（HSS），the cause of formation and the harmful influence of HSS on desulfurization unit with alkanolamine solution were reviewed. The technologies and applications of removing HSS, focusing on the technologies and application status of removing HSS with anion exchange resin. It is suggested that the fixed-bed ion-exchange resin amine purification technology with domestic resin should be adopted in combination with the existing alkanolamine de-H2S device as well as the on-site utilities to reduce the amine liquid loss of the amine purification unit and the entering of reclaimed water, thus to reduce energy and material consumption.

ANALYSIS OF ABNORMAL OPERATION FLUCTUATION IN SOLVENT REGENERATION UNIT AND COUNTERMEASURES

2020, 51(4):  50-53. 

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In July 2018, there were several abnormal fluctuations in the operation of No.2 solvent regeneration unit of SINOPEC Luoyang Company, resulting in tower flooding, which seriously affected the product quality of upstream unit and the SO2 emission of sulfur recovery unit. By analyzing the reasons, the optimization and adjustment were made by following measures: adding amine liquid purification device, cleaning all solvents by filtering, controlling the heavy component content fraction of liquefied gas and dry gas of FCC desulfurization device to lower than 2% and 3%, respectively, and reducing the pressure of amine-rich liquid flash tank to less than 0.05 MPa. Finally, the device run smoothly, the quality of lean liquid and catalytic desulfurization products were qualified, and the consumption of MDEA was reduced to meet the requirements of environmental protection.

INDUSTRIAL PRACTICE OF BLENDING HVGO AS FCC UNIT FEED

2020, 51(4):  54-58. 

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An industrial practice of blending feedstock for FCC unit with vacuum gas oil from the fourth side-line has carried out in CNOOC Huizhou Petrochemical Company, which can optimize the product structure of the whole plant and improve economic benefits. The results showed that after blending ratio of the vacuum gas oil to 8.59%, the total liquid yield was decreased by 0.77 percentage point, the coke yield was increased by 0.33 percentage point, and the energy consumption was increased by 116.47 MJ/t; the molar ratio of H2/CH4 of catalytic dry gas was increased slightly, the olefin content of liquefied petroleum gas and gasoline were increased by 0.21 percentage point and 1.3 percentage points, respectively, the gasoline density（20 ℃） was increased by 2.1 kg/m3 and RON was increased by 0.6 unit, the aromatics content of gasoline was increased by 1.9 percentage points, and the benzene content of gasoline was decreased by 0.08 percentage point. The contents of Ni and Ca on equilibrium catalyst were increased by 388 μg/g and 2 462 μg/g, respectively, and would continue to increase over time, which would threaten the long-term operation of FCC unit. Measures should be taken to ensure long-term operation of FCC unit, such as optimizing crude oil varieties, intensifying crude oil desalination, increasing catalyst replacement speed, and adding multi-functional metal passivator.

STUDY ON CONVERSION LAW OF NITROGEN COMPOUNDS IN EBULLATE BED RESIDUE HYDROTREATING

2020, 51(4):  59-63. 

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The hydrotreating of Jiujiang pipeline oil vacuum residue was carried out in a bench scale ebullated bed reactor. The structures of nitrogen compounds in feed and hydrotreated oils under different temperatures were investigated by using the Orbitrap mass spectrometry. The results showed that the nitrogen compounds in the vacuum residue include basic nitrogen compounds and neutral nitrogen compounds, with the types including N1, N1O1, N2, N2O1, mainly N1 compounds. In the conversion of feedstock, the carbon number distribution and equivalent double bond number (DBE) of the basic nitrogen compounds moved toward higher carbon munber and lower DBE; and the higher the reaction temperature, the more obvious the trend. With increase of reaction temperature, the DBE of neutral nitrogen compounds decreased,and for the intensifying of the thermal cracking reaction,the carbon munber was reduced.

GAS-LIQUID DISPERSION PERFORMANCE IN AN UP-FLOW REACTOR

2020, 51(4):  64-68. 

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The effect of apparent gas velocity, axial height, diameter of riser and shape of solid particles on gas holdup distribution was investigated in cold mold test equipment with perforated plate gas - liquid distributor with cylindrical riser. The results showed that the initial bubble size generated by the gas-liquid distributor was large, mostly millimeter-scale bubbles. The uniformity of the gas holdup distribution became worse with the increase of gas velocity and the axial height. The gas dispersion performance of the gas-liquid distributor with a 26 mm riser is better than the gas-liquid distributor with a riser diameter of 48 mm. The ceramic ball, tooth spherical and clover-shaped particle all had a breakup effect on the bubble, and the breakup effect of the clover-shaped particle is better than ceramic ball and tooth spherical particle. The unevenness distribution of gas hold above the filler layer using clover-shaped solid particles is the smallest.

STUDY ON THERMODYNAMICS OF ESTERIFICATION OF NAPHTHENIC ACID COMPOUNDS

2020, 51(4):  69-73. 

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In order to avoid the drawbacks of thermodynamics analysis for esterification of naphthenic compounds reported in the literatures, where use only one type of naphthenic compound, and the great deviation between the actual situation and the calculated results by the group contribution method, six model naphthenic acid compounds were selected including five-membered and/or six-membered ones with single, double and triple rings, respectively. The B3LYP algorithm of the Gaussian 09 program was used to calculate the thermodynamics parameters (ΔH,ΔS,ΔG) of the esterification of the model compounds with methanol, ethanol and ethylene glycol at temperature of 423.15-563.15K, and the parameter results were analyzed. It was showed that cyclohexanoic acid is easier than other naphthenic acid to react with the alcohols; the higher reaction temperature is favorable for the esterification. The thermodynamic results were analyzed and verified by molecular frontier orbital analysis.

DEVELOPMENT OF LUBRICATING OIL FOR HELICOPTER TRANSMISSION SYSTEM

2020, 51(4):  74-80. 

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To meet the requirements of the advanced helicopter transmission system, a type of helicopter transmission lubricating oil was developed with reference to specification issued by the U.S. Department of Defense DOD-PRF-85734A, using polyol ester as a base oil, the self-synthesized oligomer antioxidant and extreme pressure antiwear agent. The properties of the synthesized lubricating oil are similar with a foreign reference sample in viscosity, acid number, rubber compatibility and thermal oxidative stability, but better in extreme pressure antiwear property. The bench test and flight test proved that the developed lubricating oil can be used in advanced types of helicopters.

STUDY ON EVAPORATION PROPERTY OF ETHANOL GASOLINE (E10) AND ITS CONTROL MEASURES

2020, 51(4):  81-86. 

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Because of the significant difference in the compositions of gasoline fractions from different production processes and the non-ideality of the hydrocarbon-ethanol solution, the quality control of ethanol-gasoline blending process is difficult. In this paper, the compositions of gasoline fractions from six different sources were analyzed. Six kinds of E10 gasoline with 10% ethanol were prepared. The effect of ethanol on the evaporative property of E10 gasoline was investigated based on their vapor pressure. The results showed that the E10 vapor pressure of reforming gasoline rich in aromatics increased by 17.5 kPa, the increase of vapor pressure of hydrocracking heavy gasoline E10, atmospheric gasoline E10, alkylated gasoline E10 and isomerized gasoline E10, which were rich in saturated hydrocarbons, was by 1.5-10 kPa. The change of vapor pressure of FCC gasoline E10 rich in olefins could be ignored. The distilling temperatures of 10% and 50% distillate volume of the 6 kinds of E10 were all decreased, which is beneficial to improve the low temperature starting and accelerating performance of engine. It concluded that optimizing the compositions of the ethanol gasoline (especially the content of aromatic hydrocarbons) is the key to control the vapor pressure without exceeding the upper limit.

EFFECTS OF SURFACTANT CTAB ON INTERACTION BETWEEN SILICA SURFACES

2020, 51(4):  87-95. 

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In the cationic surfactant hexadecyl trimethylammonium bromide (CTAB) solution, the changes of interactions between the silica surfaces were detected by atomic force microscopy in situ. The results showed that there were significant impacts of concentration of CTAB, electrolytes and incubation time on both the long-range interactions and adhesion forces between silica surfaces, and the wettability of the sand surfaces. In the solution without electrolyte KCl, with the increase of CTAB concentration, the adsorption amount of CTAB on the surface of silicon dioxide increases continuously, and the long-range force between the surfaces of silicon dioxide changes from attractive force to repulsive force. It was further observed that addition of KCl (10mmol/L) in CTAB solutions would enhance the colloidal interactions with the concentration of CTAB and incubation time. At 1.00 mmol/L and 10.00 mmol/L of concentration of CTAB, the long-range force became repulsive. The effect of electrolyte and stabilization time on the colloidal forces between SiO2 surfaces can reflect the changes of adsorption morphology of CTAB on SiO2 surfaces, thus reflecting the electrical properties and wettability of SiO2 surfaces.

IDENTIFICATION AND CHARACTERIZATION OF SULFUR COMPOUNDS IN DIESEL AND ITS HYDROGENATION PRODUCTS BY SOLID PHASE EXTRACTION/COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY COUPLED WITH TIME-OF-FLIGHT MASS SPECTROMETRY

2020, 51(4):  96-104. 

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Two solid phase extractions methods with PdCl2-Al2O3 were developed for the separation of sulfur compounds in high sulfur-containing diesel and hydrofined diesel. A comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF MS) method for the qualitative analysis of sulfur compounds in diesel was established. This method could effectively remove the interference of other components on sulfur compounds identification, and give the accurate data of compound types and carbon number distribution of sulfur compounds in diesels from different processing units and hydrofined diesels. The results showed that nearly 90% of sulfur compounds were concentrated in sulfur-containg component separated, with very little aromatic hydrocarbons. In straight-run high sulfur diesel and catalytic cracking diesel, 8 kinds of 757 and 4 kinds of 179 sulfur compounds were classified and characterized, respectively. In corresponding diesel hydrogenation products, 4 kinds of 98 and 3 kinds of 81 sulfur compounds were identified, respectively. More than 90% of sulfur compounds in hydrofined diesel were dibenzothiophenes with short side chain.

APPLICATION OF ADVANCED DUST REMOVAL AND DEMISTING SYSTEM IN RFCC FLUE GAS DESULFURIZATION AND DEDUST

Zhou Ziyang Pan Tao Guan Yongheng

2020, 51(4):  105-110. 

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In order to meet the new requirements of environmental protection, SINOPEC Guangzhou Company made a major revision of the flue gas desulfurization device in 2017. The original gas-liquid separator of the washing tower was revamped to an advanced dust removal and demisting system to improve the desulfurization and dust removal. The industrial application indicated that the pollution components were decreased, the demisting effect and the visual effect of defogging was optimized after the transformation. The mass concentration of the particulates was decreased from 126.6 mg/m3 to 12.8 mg/m3 while the removal rate was stable at 90%. The mass concentration of SO2 has decreased from 2832.4 mg/m3 to 3.7 mg/m3, and the removal rate being over 99%. All the important indicators of flue gas meet the pollutants emission standards in sensitive areas from petroleum refining industry (GB 31570-2015).

TECHNOLOGY OF TREATMENTING ORGANIC WASTEWATER FROM ELECTRIC DESALTING AND DECALICIFICATION UNITS

2020, 51(4):  111-115. 

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According to the needs of crude oil processing and coke quality upgrading, processes of organic acid extraction, extractant regeneration, organic acid recovery and stripper were used to treat the wastewater generated in the process of electric desalination and decalcification. Taking the wastewater samples with organic acid concentration of 3.0% as the object of investigation, based on the extraction equilibrium data of isopropyl acetate, isobutyl acetate, ethyl acetate and other ester extractants, isopropyl acetate was determined as the extractant. According to the requirements of treatment efficiency and acid concentration in water less than 0.2%, the appropriate extraction ratio (oil/water volume ratio) was determined to be 3:1, and the corresponding extraction level was 6. Under this condition, the organic acid recovery rate was 95%, and the acid concentration in the lower layer of water after extraction was 0.149%. The azeotropic distillation method was used to treat the upper layer extract, and the recovered acetic acid concentration was 96.81%. After stripping, the COD value of water quality decreased from the initial 29300mg/L to 4710 mg/L, and the COD value decreased by 83.9%. The water quality can meet the influent water quality requirements of the existing industrial wastewater treatment units of the company, and realize the reuse of organic wastewater or meet the discharge standards. At the same time, the implementation of this process can get economic benefits of 1.828 million Yuan per year.