Table of Content

12 November 2020, Volume 51 Issue 11

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DEVELOPMENT OF INDUSTRIAL CHAIN OF DCC TECHNOLOGY PLATFORM AND ITS COMMERCIAL PRACTICE

2020, 51(11):  1-6. 

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Based on the study of the reaction chemistry of DCC to produce ethylene, propylene and light aromatics, DCC plus technology with high propylene selectivity and CPP technology with ethylene and propylene production were developed, forming a DCC technology platform to meet the product needs of different users. The deep hydrotreating technology of DCC feedstock was developed. Its desulfurization rate is over 95%, denitrogenization rate is over 65%, carbon residue removal rate is over 76%, and metal removal rate is about 98%. According to the characteristics of DCC products, the characteristic chemical utilization technologies, such as dry gas liquid method for ethylbenzene, direct oxidation of propylene to epoxide, extraction distillation of DCC naphtha for BTX and hydrocracking of DCC light oil for BTX, have extended the industrial chain of DCC technology platform. All these have been successfully applied in chemical refining projects, creating a refining and petrochemical integration technology route in line with China's national conditions.

NEW TECHNOLOGY FOR FCC SLURRY PROCESSING IN DELAYED COKING UNIT AND ITS INDUSTRIAL APPLICATION

2020, 51(11):  7-12. 

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A new technology for FCC slurry processing with separate heating and post-furnace mixing steps was developed and applied in the 4.20 Mt/a delayed coking unit of CNOOC Huizhou Petrochemical Company. A separate heating furnace was set up to heat the slurry to effectively avoid the adverse effect of the slurry on the delayed coking unit. After adopting specific designs，the slurry processing system can steadily run for a long period. The yield of coker gas oil increased by 0.98 percentage points，the yield of coke increased by 2.10 percentage points，and the yield of gasoline and diesel decreased by 3.09 percentage points. The properties of dry gas, LPG，gasoline and diesel had little changed, while the properties of coker gas oil became heavier, and the ash content in coke increased, but it did not affect the operation of downstream units and the sale of products. Compared with selling slurry as fuel oil, the new processing method can increase profit by 101.2 million Yuan per year. This technology has high operation flexibility, which can mix other materials according to the demand, increase the outlet temperature of the heating furnace, and increase the reaction depth of residue in the coke tower, thus obtaining higher economic benefits.

EXPERIMENTAL STUDY ON REDUCING DIESEL/GASOLINE RATIO BY BLENDING RESIDUE HYDROTREATER DIESEL INTO FCC FEEDSTOCK

2020, 51(11):  13-16. 

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In order to adjust the product structure economically and efficiently, experimental study on reducing diesel/gasoline ratio by blending residue hydrotreater diesel into FCC feed was carried out. The results showed that, compared with the RFCC residue feed, the residue hydrotreater diesel has better cracking performance and gasoline selectivity. The conversion rate was as high as 79.46%, and the gasoline yield was up to 62.72%. When blended with 5.34% of residue hydrotreater diesel, diesel production could be reduced by 198.4 t/d, and the high octane number gasoline production increased by 154.1 t/d, resulting in a significant reduction of diesel/gasoline ratio, meanwhile the octane number of gasoline increased by 0.2 unit.

RESEARCH OF REMOVAL OF POLYCYCLIC AROMATIC HYDROCARBONS FROM COAL-BASED HYDROCRACKING TAIL OIL BY SOLVENT EXTRACTION

2020, 51(11):  17-21. 

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Furfural was used as extraction solvent to remove the polycyclic aromatics (PCA) from the coal-based hydrocracking tail oil. The effect of extraction temperature, ratio of solvent to oil and extraction stages on the yield and the removal rate of PCA in raffinate oil was investigated. With single-stage extraction process, increasing the extraction temperature or the ratio of the solvent to feed resulted in reduction of the raffinate yield and increase of the removal rate of PCA. The removal rates of PCA of the raffinate were both more than 72.0% and the yields of the raffinate were both more than 70.0% in two-stage and three-stage counter-current extraction processes. Meanwhile, the raffinate oil still had high content of unextracted monocyclic and bicyclic aromatics and the aromatic carbon rate CA was greater than 10.0%, which is conducive to the production of co-friendly coal-based rubber oils.

RESEARCH ON PREPARATION OF PHASE CHANGE PARAFFIN WAX WITH LOW MELTING POINT BY UREA DEWAXING

2020, 51(11):  22-26. 

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Using the No.1 vacuum cut as raw material，the technology for preparation of phase change wax with low melting point by urea dewaxing were studied. The results showed that the optimum process conditions was that the complexation temperature was 25 ℃，the adding amount of urea solution was 91%，the composition of urea solution was m（urea）：m（isopropyl alcohol）：m（water）=45：35：20，the reaction time was 60min，the mass ratio of washing solvent to oil was 76%. Under these conditions，the yield of crude wax was 28.2% with a melting point of 29.6 ℃，the mass fraction of n-alkanes in crude wax was 94.9%，and the condensation point of dewaxed oil was less than －60 ℃. The phase change wax with a melting point of 31 ℃, and an enthalpy of 201.9 kJ/kg was obtained after perspiring.

RESEARCH ON HYDROGENATION CATALYST FOR REMOVAL OF ORGANIC OXIDES FROM FISCHER-TROPSCH SYNTHETIC OIL

2020, 51(11):  27-34. 

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Fischer-Tropsch(F-T) synthetic oil contains a small amount of organic oxides, which affect the yield and selectivity of PAO prepared by olefin polymerization. The removal of organic oxides, such as aldehydes and ketones, in F-T synthetic oils was carried out by a process as follows: the oxygen-containing compounds (mainly aldehydes and ketones) in the F-T synthetic oils were first selectively hydrogenated to produce corresponding alcohols followed by translating into sodium alcoholate by reaction of alcohols and sodium metal, and then the sodium alcoholate were removed by distillation to remove the oxygen-containing compounds. In this thesis, Cu，Cu-Zn，Cu-K，Cu-Ni and Pt catalysts were prepared using α-Al2O3 and γ-Al2O3 as supports, respectively, and characterized and tested for the hydrodeoxygenation performance of F-T synthetic oils. The research data indicated that the main components of F-T synthetic oils were olefins and alkanes, and the oxygen-containing compounds were mainly small amounts of alcohols, ketones and aldehydes. The hydrogenation can remove oxides, but has a saturation effect on olefins. The test results showed that the selectivity of the catalyst with α-Al2O3 as the carrier is better than the catalyst with γ-Al2O3. Cu-Zn/α-Al2O3 catalyst had the best effect. Under the conditions of a pressure of 1 MPa, a temperature of 180 ℃, a space velocity of 2 h-1 and a volume ratio of hydrogen/oil of 50, and the simulated oil as test feed, the olefins loss was 12% and the aldehyde hydrogenation conversion rate reached 95.3%, and no reaction of alcohol hydrogenation to hydrocarbons was found.

OPTIMIZATION AND LONG TERM OPERATION OF GASOLINE AND DIESEL HYDROTREATING UNIT

2020, 51(11):  35-39. 

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The fresh ultra-deep hydrodesulfurization catalysts RS2100/RS2110 (developped by SINOPEC Research Institute of Petroleum Processing) and regenerated FHUDS catalyst series (developped by SINOPEC Dalian(Fushun) Research Institute of Petroleum Processing) were used in a 1.67 Mt/a hydrotreating unit processing mixed feedstock of coker gasoline, coker diesel and atmospheric gas oil in SINOPEC Tahe Refinery & Chemical Company. The national VI standard diesel was obtained with flash point (closed) of 68℃，S content of 3.2 μg/g，nitrogen content of 0.67 μg/g， cetane number of 52，and poly-aromatic hydrocarbons content of 2.9 %. However, the deactivation rate of catalysts was to 24.0 ℃/a within half a year. After adjusting the temperature distribution of two reactors，raw material composition as well as the sulfur content of products， the catalyst deactivation rate was reduced to less than 14.4 ℃/a，the pressure drop of reactors was 0.4 MPa, and the maximum temperature of reactor bed was less than 390 ℃, indicating a good stability of the catalysts system. The catalysts can meet the need for long term operation.

EFFECT OF SOLVENT ON COMPLEXATION REMOVAL OF NITROGEN COMPOUNDS FROM SIMULATED DIESEL FUEL

2020, 51(11):  40-45. 

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The effect of solvent on the removal of nitrogen-compounds from petroleum fractions by complexation reaction was investigated. A series of representative metal salt complexing agents and model compounds were selected for complexing reaction. The effects of metal salts on removal of nitrogen compounds by complexing in different solvents were studied by gas chromatography-mass spectrometry (GC-MS). The results showed that the solvent effect was significant on the removal of basic nitrogen compounds by metal complexation for some of the metal salts. The ethanol could promote the dissolution of the salts and dissociation of ions, helpful to remove out the basic nitrogen compounds by Fe2 (SO4)3, ZnSO4, CuSO4, NiSO4 and PdCl2. Toluene and ethanol improved the removal efficiency of basic nitrogen compounds for CuCl2. However, the solvent effect on the removal of basic nitrogen compounds by ZnCl2 was inconspicuous. The side reaction was occurred during the process of denitrogenation by FeCl3 in ethanol, forming by-products including chlorinated aromatics and polymers.

INFLUENCE OF SULPHATE RADICAL ON SELECTIVE HYDRODESULFURIZATION ON Ni/γ-Al2O3 CATALYST

2020, 51(11):  46-52. 

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A series of hydrodesulfurization catalysts modified by H2SO4, Ni (NO3)2, Ni (NO3)2-H2SO4, NiSO4, respectively were prepared by the incipient wet impregnation method with γ-Al2O3 as carrier. The effects of sulfate radical on the physicochemical properties and thiophene selective HDS performance were studied by XRD, BET, H2-TPR, FT-IR, XPS and UV Raman spectroscopy. The HDS performance was tested in a small fixed bed using cyclohexane solution containing thiophene and isopentene as feedstock. The results showed that the hydrodesulfurization activity and selectivity of Ni/γ-Al2O3 modified with sulfate radical was better than the one modified with Ni(NO3)2; the catalyst prepared with nickel sulfate showed the highest activity and selectivity, 19 percentage points and 78% higher than the catalyst from nickel nitrate, respectively. The differences in catalytic activity were associated with the form of Ni in the catalyst, the presence of sulfate radical, on the one hand, weakens the interaction between the Ni and carrier, on the other hand, provides the sulfide agent for sulfidation of Ni in situ to form nickel sulfide. Both nickel sulfide and NiSO4 form the reactive center of catalysts, its activity and selectivity for HDS is significantly higher than the catalyst sulfided by introduction of sulfidation agent.

EFFECT OF THERMAL TREATMENT METHOD ON STRUCTURE AND HYDRODENITROGENATION PERFORMANCE OF NiMoAl CATALYST

2020, 51(11):  53-58. 

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The NiMoAl catalyst precursor synthesized by sol-gel method was thermal treated in air, nitrogen and liquid paraffin, respectively, to prepare 3 kinds of NiMoAl catalysts. The physical and chemical properties of these catalysts were analyzed by X-ray diffraction (XRD), thermogravimetry-mass spectrometry (TG-MS), nitrogen adsorption-desorption, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and transmission electron microscopy (TEM). Using quinoline hydrodenitrogenation (HDN) as a reaction probe, the effect of precursor thermal treatment on the catalytic hydrodenitrogenation performance of NiMoAl catalyst samples was investigated. The results showed that the NiMoAl catalyst prepared by liquid-phase thermal treatment had larger pore volume and higher active metal dispersion in comparison with the sample calcinated in air. Besides, the aggregation of MoS2 was found on the surface of the catalyst calcinated in nitrogen. Compared with other two thermal treatment methods, the NiMoAl catalyst obtained through liquid-phase thermal treatment exhibited a higher selectivity for denitrogenation products in the HDN reaction of quinoline.

DEVELOPMENT OF NOVEL OIL-WATER SEPERATING AGENT FOR PRODUCED FLUID BY SURFACTANT-POLYMER BINARY FLOODING

2020, 51(11):  59-63. 

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To solve the oil-water separation problem of produced fluid by surfactant-polymer binary flooding in SINOPEC Shengli Oilfield, polymethacrylic acid polyether containing cationic monomer was synthesized in the laboratory, and the oil-water separating agent RPYSF-1 for the produced fluid was then prepared. The field tests were carried out in Gusi United Station of Gudao Production Plant of Shengli Oilfield Branch of SINOPEC. The results showed that the total agent dosage decreased from 78.2 μg/g before the test to less than 50 μg/g, the water content (w) of the oil transmission was no more than 1.2%, and the mass concentration of oil in sewage was no more than 39mg /L, reaching the expected targets

NEW OXIDATION PROCESS TECHNOLOGY FOR VOCs TREATMENT IN REFINING AND CHEMICAL ENTERPRISES

2020, 51(11):  64-70. 

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A new process technology for treatment of VOCs by using FCC regenerator in normal production state of refinery was developed, which is used for high efficiency and low energy consumption treatment of VOCs with different concentrations and types discharged from different pollution sources of refinery. By controlling the concentration and temperature of VOCs waste gas entering the regenerator, and applying high grade flame arrester, one-way valve and other safety measures, the safety of VOCs waste gas transportation and treatment process was ensured. Due to the catalytic oxidation performance of heavy metals deposited on the surface of catalytic cracking catalysts, the developed technology has a good VOCs removal effect at a relative low combustion temperature (670 - 720℃). The industrial applications showed that after the treatment the VOCs concentration in the flue gas was less than 10mg / m3, which fully meets higher requirements of SINOPEC control standard for VOCs（no more than 15mg/m3）. Meanwhile, the technology had no impact on the normal production of FCCU, product properties, and desulfurization and denitrogenation of regenerator flue gas.

EXPLORATION OF SLUDGE ADSORBENT APPLIED IN OILY WASTEWATER AND INDUSTRIAL OILS

2020, 51(11):  71-75. 

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Sludge adsorbent was prepared from oily sludge and walnut shell and applied in the treatment of oily sewage and the adsorption of industrial oils. The results showed that the carbon content of sludge adsorbent was 87.69% with a loose surface texture and well-developed pores. The pore structure mainly consisted of mesopore. Under the same conditions, the treatment effect of sludge adsorbent on oil in oily wastewater was better than that of activated carbon significantly, the treatment effect of sludge adsorbent after regeneration by heat treatment on oily wastewater was slightly lower than that of new agent, but it was still superior to activated carbon that was also heat regenerated; The initial instantaneous adsorption rate of sludge adsorbent applied to industrial oils was higher than that of activated carbon. The initial instantaneous adsorption rate of sludge adsorbent after heat regeneration was improved, better than that of new agent. With the increase of regeneration times, the initial instantaneous adsorption rate increased continuously; the saturated adsorption capacity of sludge adsorbent regenerated by heat treatment for industrial oils was always higher than that of activated carbon regenerated, and the time for reaching saturated adsorption was faster, and the sludge adsorbent can maintain a stable adsorption capacity for industrial oils after repeated regeneration.

DETERMINATION OF TRACE ELEMENTS IN ORGANIC MOLYBDENUM BY INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROMETRY

2020, 51(11):  76-81. 

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The oil soluble organic molybdenum was diluted by organic solvent with certain proportion. The trace element contents in oil-soluble organic molybdenum was determined by inductively coupled plasma optical emission spectrometry（ICP-OES）, such as aluminum, barium, calcium, chromium, copper, iron, potassium, magnesium, manganese, sodium, nickel, phosphorus, lead, silicon, vanadium, and zinc. A simplified and rapid method for the analysis of trace elements in organic molybdenum samples was established. The element spectral lines of samples interfered by Mo were determined by preparation and analysis of samples, and the appropriate analytical spectral lines were selected to eliminate the molybdenum matrix spectral interference. The precision of the established method was investigated, and then the trace elements in the actual samples were determined by the method and the GB/T 17476-1998 method, respectively and compared. The results showed that by the new method, the relative standard deviation of each element was less than 2%, and the spike recovery was 95%-109% at the appropriate spectral line when the oil soluble organic molybdenum was diluted 100 times with ICP diluent. The method is rapid, accurate and is able to determine multiple elements in the oil soluble organic molybdenum simultaneously.

SELECTION OF DENSITY CONVERSION TABLES FOR DIFFERENT PETROLEUM PRODUCTS

2020, 51(11):  82-85. 

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Using automatic densitometer, the density at different temperatures of different types of petroleum products were measured and converted into the standard density (20 ℃). The maximum difference method and density (20 ℃) comparison method were used to treat and analyze the data. The results showed that for hydrocracking tail oil, VGO, recycle oil, lubricating oil and atmospheric residuum, the density conversion Table D in the national standard “Petroleum Metering Table” (GB / T 1885-1998) should be selected, while the Table B should be selected for FCC slurry and heavy oil with low viscosity. By comparing the difference between the conversion density and the linear fitting standard density at different temperatures, it was found that the lower the test temperature, the more accurate the converted standard density. The correct selection of density conversion table and test temperature could improve the accuracy of density measurement of petroleum products and provide more reliable data for refining and chemical enterprises.

APPLICATION OF ADDITIVES IN PREPARATION OF SUPER OVERBASED CALCIUM SALICYLATE

2020, 51(11):  86-89. 

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The preparation method of super overbased calcium salicylate was introduced. The effect of additives on the product yield was studied by using co-surfactants and co-promoters. The results showed that with the increase of the amount of co-surfactant, the yield of the product increased gradually and reached a balance; the addition of co-surfactants such as stearic acid, alkyl benzenesulfonic acid and dodecylphenol significantly improved the yield of the product. In the co-promoters, acetic acid was the most effective co-promoter and the yield was the highest when the dosage (w) was 1.5%. Result showed that when co-surfactant used together with the acetic acid the product yield was higher than both the yields when used alone. Among them, the effects of stearic acid and acetic acid combination was the best, with the product yield as high as 98%. The prepared super overbased calcium salicylate has low viscosity, good compatibility with sulfonate and excellent comprehensive performance.

RESEARCH ON SYNTHETIC COMPRESSOR OILS BASED ON POLYETHER

2020, 51(11):  90-93. 

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Using polyether base oil, a kind of polyether type synthetic compressor oil was developed by screening and investigating the properties of additives such as antioxidation agent, extreme pressure antiwear agent, co-solvent and anti-rust agent. The viscosity index of the product was more than 210, the rotary oxygen bomb time was more than 1000 minutes, the copper strip corrosion（100 ℃，3 h） was grade 1b, and the scar diameter after the four ball milling test was about 0.5mm. The developed product has an excellent performance in viscosity-temperature，oxidation stability，rust resistance and anti-corrosion and good extreme pressure anti-wear. The quality of the product reached the level of foreign similar oils. After practical use for one year，the wear metal content was less than 30 μg/g, showing that the developed product can meet the lubrication requirements of hydrocarbon gas compressors.

SYNTHESIS AND PROPERTIES OF CORROSION INHIBITOR DIETHYL AMINO METHYL BENZOTRIAZOLE

2020, 51(11):  94-98. 

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Mannich（DMBM）base corrosion inhibitor,diethyl amino methyl benzotriazole was synthesized using formaldehyde（40% mass fraction）benzotriazole and diethylamine as raw materials. The optimal synthesis reaction conditions were: n(formaldehyde):n(diethylamine): n(benzotriazole) was 3:2:3, the reaction temperature was 25 ℃, and the reaction time was 0.5 h. The structures of the synthesized product were characterized by IR and NMR. The corrosion inhibition effect on carbon steel in 10% hydrochloric acid solution was investigated by weight loss method. The results showed that the synthesized DMBM had a good corrosion inhibition in an acidic medium duo to the adsorption of the benzotriazole ring in the molecule and the N atom with lone pair electrons on the amine group to the metal surface. By adding 2% DMBM into 10% hydrochloric acid solution, the corrosion rate of carbon steel at 50 ℃ was measured as 0.94mm /a, and the corrosion inhibition rate was 93%. The polarization curve test showed that DMBM is a mixed inhibitor mainly for inhibiting anodic corrosion reaction.

ANALYSIS OF SCALING DURING THE PRETREATMENT PROCESS OF SZ36-1 CRUDE OIL

2020, 51(11):  99-102. 

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The scaling locations in the heat exchanger processing SZ36-1 crude oil in a refinery were analyzed. XRD, IR, and hydrocarbon element analysis techniques were used to characterize the main components of the scale. The XRD results showed that the inorganic components in the scale except sand mainly came from the water corrosion in crude oil on pipelines and equipment. The hydrogen-carbon ratios of the scale and the crude oil indicated that the organic components in the scale mainly came from crude oil.The infrared spectroscopy results indicated that the scale contained acrylamide polymers, and its characteristic peak was consistent with the hydrophobically associated polyacrylamide injected in upstream process. It was believed that the generation of scale was related to the hydrophobic associated polyacrylamide added during the oil recovery process. The dynamic simulation showed that when water content was more than 5% and at 85℃，scaling occurred in the position of heat exchanger where flow rate was low. At the same time, the physical properties of the simulated scale were consistent with the scale samples collected from the oil refining device, which further proved that polyacrylamide mainly acts as agglomeration and crosslinking, binding the crude oil material to form scale.

SIMULATION STUDY ON EXTRACTIVE DISTILLATION OF F-T SYNTHETIC ALCOHOL-WATER MIXTURE

2020, 51(11):  103-110. 

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In this paper, simulation study on extractive distillation of F-T synthesis alcohol-water azeotropic system was carried out. Ethylene glycol (EG), N, N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) were added to the simulated mixed alcohol-water system, respectively. The best extractant was selected by evaluating the extractive distillation dehydration effect of the three solvents by UNIFAC model, and applied to the phase equilibrium and continuous distillation test of simulated mixed alcohol feed. The results showed that the effects of EG and DMSO were better than that of DMF. Considering the stability of the extractant, EG was considered as the best extractant for the dehydration of mixed alcohol-water system. When EG was used as extraction agent, the dehydration effects of different solvent ratios were in good agreement with those of UNIFAC. With the increase of solvent ratio, the water content in material at the top part of the distillation column decreased continuously. When the solvent ratio was 3:1, the water mass fraction at the top part of the distillation column could be reduced to less than 0.5%.