Table of Content

12 May 2017, Volume 48 Issue 5

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EFFECT OF COLD FLOW IMPROVER ON EXISTING STATE OF DIESEL MOLECULES

2017, 48(5):  1-9. 

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The existing states of different diesel molecules at different temperatures were simulated by molecular dynamics. It is found that the main reason for the aggregation and crystallization of n-alkanes at low temperatures is the changes of molecular conformation from “curved” to “straight” as the temperature decreases, and that keeping n-alkanes in curved conformation is beneficial to improve the low temperature flow performance of n-alkanes system. The conformation changes of existing states of n-alkane molecules in diesel containing low temperature flow improver (CFI) when the temperature decreases were investigated. The results show that CFI can change the molecular torsion angle by the intermolecular force to keep the curved comformations, resulting in a weak intermolecular force and diminished order and compactness of n-alkanes. The CFI molecules that can extend to multiple directions, contain multiple high degree curved molecular segments and strong interaction with n-alkanes can significantly keep n-alkane molecules in curved conformation.

CAUSE ANALYSIS OF FINAL BOILING POINT RISING OF GASOLINE PRODUCT IN S-ZORB PROCESS

2017, 48(5):  10-14. 

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The S Zorb process can produce low sulfur gasoline. However, the final boiling point (FBP) of the product gasoline rises. To find the reason, the boiling ranges and compositions of the products before and after S Zorb process were investigated in a micro-fixed reactor using FCC gasoline and straight-run gasoline as feedstocks from SINOPEC Cangzhou Company and fromYanshan Refinery, respectively. Results show that the FBP of the product rises with the rise of the reaction temperature. The increase of aromatic hydrocarbons and high boiling point aromatics in heavy distillates, the existence of olefins which cause the increase of carbon number of the components are the primary reasons of the FBP rising. In addition to the hydrogenation of hydrocarbons < C5, the cyclization of alkanes and dehydro-aromatization of naphthene occurs as well. However, under laboratory conditions, the mole ratios of H/C change little.

COMPARATIVE ANALYSIS AND ORIGINATION OF PHENOL AND THIOPHENOL DERIVATIVES IN COKER NAPHTHA AND DIESEL

2017, 48(5):  15-20. 

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The extractable acidic compounds were obtained by extracting delayed coking naphtha and diesel from different sources with 20% NaOH. These extractable acidic compounds were analyzed by gas chromatography–mass spectrometry (GC-MS). The results show that the extractable acidic compounds in coker naphtha contain thiophenols and small molecule thiols in addition to phenols. Differs from coker naphtha, almost all extractable acidic compounds in coker diesel are phenols. Excellent linearity between the thiophenols content (y) in coker naphtha and the sulfur content (x) in the corresponding vacuum residue feedstock is observed [y =0.04x–0.005 06 (R2=0.999)]. The higher content of thiophenols in coker naphtha, the worse its storage stability at room temperature. The stability of the coker naphtha is greatly improved after caustic wash. The origin of phenols may be related to the hydrolysis of aryl ether bond and the oxidative decarboxylation of aromatic acids in the delayed coking process. The thiophenols may come from the reaction of the phenols with H2S at high temperature.

PREPARATION AND STORAGE STABILITY OF SULFUR MODIFIED EMULSIFIED ASPHALT

2017, 48(5):  21-26. 

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The sulfur modified asphalt was prepared by adding 10% sulfur to sample asphalt at 130 ℃, followed by preparation of sulfur modified emulsified asphalt by mixing the product with emulsifier A 3%, thickening agent 0.45%, KCl 1.5%. Through the measurement of penetration, softening point, ductility, storage stability and Engler viscosity, the effects of different dosages of emulsifier A and stabilizer, the sulfur modification methods and the amount of sulfur added to asphalt on the performance and storage stability of emulsified asphalt were investigated. The evaluation results show that the prepared sulfur modified emulsified asphalt can satisfy with the requirements of the common emulsified asphalt standard.

EFFECT OF EMULSIFICATION CONDITIONS ON STORAGE STABILITY OF HIGH VISCOSITY MODIFIED ASPHALT EMULSION

2017, 48(5):  27-30. 

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The effects of preparation conditions such as emulsion temperature and emulsifier solution, outlet pressure of colloid mill, emulsifier content as well as SBS content in modified asphalt on the storage stability of high viscosity modified asphalt emulsion (HVMAE) were investigated. The relations between average size of high viscosity emulsified asphalt and storage stability were studied by laser particle analyzer. The results show that the storage stability of HVMAE firstly decreases and then increases as emulsion temperature and SBS dosage increases, but reduces first followed by a slow decline trend with the increase of outlet pressure of colloid mill, indicating a positive relations of storage stability with average particle size. Under the optimum conditions: SBS modified asphalt at 165 ℃， emulsifier solution temperature of 55 ℃, outlet pressure of colloid mill 0.2 MPa, dosage of emulsifier 0.4% and SBS content in modified asphalt 3.2%, the prepared HVMAE was applied successfully in overhaul project for Beijing West Chang'an Avenue in 2014 and 2016.

INDUSTRIAL APPLICATION OF HIGH LIQUID YIELD ADDITIVE SLE FOR FCC PROCESS

2017, 48(5):  31-36. 

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The present paper introduces the industrial application of the high liquid yield additive SLE for FCC process in a RFCC unit of SINOPEC Jingmen Company with a capacity of 1.2 Mt/a. The results show that when the content of the additive attains a level of 10.7% in the inventory, comparing with the blank test, the increases of total liquid yield and gasoline yield are 2.79% and 5.56%, respectively, while the decreases of slurry, coke, and LCO yields are 1.31%, 0.79%, and 4.60%, respectively. It is noticeable that the residue content of the feedstock is increased by 3% during all the period of the test. Except the properties of slurry and LCO are somehow worse than that of blank test, no other significant changes are observed. The results prove that the additive significantly enhances the profit of the RFCC unit by improving residue conversion and enhancing liquid product yield.

SYNTHESIS AND CHARACTERIZATION OF SAPO-11 ZEOLITE WITH SPECIAL CRYSTAL STRUCTURE

2017, 48(5):  37-42. 

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A special crystal structure SAPO-11 zeolite was synthesized by using composite template in acidic conditions and characterized by SEM, XRD, FT-IR, NMR, CRF, BET, DTA and TGA techniques. Its isomerization activity for meta-xylene was evaluated in a small scale continuous flow fixed bed. The results were compared with that of the comparative SAPO-11 zeolite made from single template. The crystal morphology characterized by SEM demonstrates the existence of special crystal structure in each crystal of the samples using composite template; in addition, the physicochemical properties of this sieve having high thermal stability and strong acid are different from the comparative one, resulting in high activity for meta-xylene isomerization reaction.

EFFECTS OF CARBON AND SILICON DEPOSITION ON ACTIVITY OF HYDROGENATION CATALYST AND REGENERATION PERFORMANCE

2017, 48(5):  43-47. 

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Coke and silicon deposition has a great but different influence on the activity of hydrotreating catalyst and regenerated catalyst. The properties of the catalysts after deactivation and regeneration were characterized by TG-DSC, Raman spectroscopy, N2 adsorption-desorption, TPR and SEM-EDS techniques. It is found that the sulfur and carbon compounds is easy to decompose on the deactivated catalyst caused by carbon deposition, the pore structure can be restored close to 90% of fresh catalyst, while the pore structure of deactivated catalyst caused by deposition of silicon has a great loss, and large particles of MoS2 as well as the graphitized carbon appears. TPR tests show that the interaction between the metal and the carrier increases after silicon deposition, resulting in higher reduction temperature and difficult to be sulfided completely. The results of activity evaluation show that the activity of coke-deactivated catalyst can be recovered after regeneration, while the activity of silicon-deactivated catalyst is much poor.

APPLICATION OF DENITRIFICATION ADDITIVE TUD-DNS ODEP IN PARTIAL REGENERATION RFCCU

2017, 48(5):  48-51. 

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The application of denitrification additive TUD-DNS ODEP in RFCCU of SINOPEC Guangzhou Company was introduced. The results demonstrate that when additive dosage is 2.54% of total catalyst inventory, the NOx content is reduced from 210 mg/m3 to 110 mg/m3 and the NOx removal rate is about 48%. Temperature reduction of CO incinerator improves the NOx removal rate; and the additive addition has no adverse influence on product distribution and properties.

SYNTHESIS OF ORDERD MESOPOROUS ALUMINA AND ITS APPLICATION IN PREPARATION OF HEAVY METAL TOLERANCE FCC CATALYST

2017, 48(5):  52-55. 

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Ordered mesoporous alumina was synthesized through solvent evaporation induced self assembly method with aluminium isopropoxide as aluminum source and P123 as template, and used as matrix component for preparation of new heavy metal tolerance FCC catalyst. Characterization results indicate that the alumina synthesized possesses ordered mesopores with surface area of 233 m2/g and pore volume of 0.55 cm3/g, which remarkably promote pore structure properties of FCC catalyst. The catalytic performance evaluation results illustrate the distinct improvement of heavy metal tolerance for FCC catalyst using this ordered mesoporous alumina. Compared with traditional catalyst, the dry gas, coke and heavy oil yields of the obtained catalyst decrease by 0.3, 0.92 and 0.25 percentage point, while the yields of gasoline, total liquid and light oil increase by 1.23, 1.53 and 1.02 percentage points，respectively.

INDUSTRIAL APPLICATION OF FHUDS-6 UITRA-DEEP HDS CATALYST IN 3.0 MT/A DIESEL HYDROTREATING UNIT

2017, 48(5):  56-59. 

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The national V standard diesel was produced in a fixed bed diesel hydrotreating unit with 3.0 Mt/a capacity in Maoming Petrochemical Company by adopting ultra-deep HDS catalyst FHUDS-6 developed by FRIPP. The calibration results show that the process runs smoothly and the sulfur content of diesel product is only 5 μg/g, meeting the national V emission standard.

TECHNOLOGIES AND MEASURES FOR INCREASING GASOLINE PRODUCTION

Yong-Lin LI

2017, 48(5):  60-69. 

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To increase the gasoline production through optimization of product slate is the major objective for refineries in present and future to meet the market demand and improve the economic benefit. Considering the actual situation of the plant, various technologies, potential and optimal measures for increasing gasoline production were discussed. Increasing gasoline production needs new processes, new catalysts as well as optimizations of technical processes, production schemes, operation parameters and gasoline formulas, while the coordination of the oil refining and chemical sectors is also needed to realize the goal of more gasoline production.

SOLUTIONS FOR PRODUCTION OF CHINA VI GASOLINE

2017, 48(5):  70-75. 

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Based on the analysis of present gasoline production and the plant process simulation, 14 solutions for production of China Ⅵ gasoline were discussed. The results show that in the first stage of gasoline quality upgrading, in which olefin volume content is less than 18%, the case consisted of FCC for olefin reduction-isomerization-alkylation is the best. In the second stage of gasoline quality upgrading in which olefin volume content is less than 15%, the process composed of large etherification (refined gasoline from two S Zorb units as feed) plus once-through mode isomerization is the best. For the solution including a new set of reforming unit, one new reforming unit-small etherification (refined gasoline from one S Zorb unit as feed) - isomerization with cycling mode is the best. It is concluded that the combination process of etherification and isomerization is recommended because it costs least and has the best benefit.

APPLICATION OF PARTITION AMMONIA INJECTION IN SCR DENOX OF REFINERY FLUE GASES

2017, 48(5):  76-80. 

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Uneven distribution of temperature on the same cross-section of a SCR (selective catalytic reduction) deNOx reactor results in an uneven distribution of concentration of NOx, which seriously affects the SCR deNOx effect. Further, the traditional uniform ammonia injection method fails to effectively address the problem of low removal efficiency and local ammonia slip. In this work, the SCR deNOx device of refinery self-provided boilers was studied. The partition ammonia injection technique was employed to improve the NOx distribution and diminish the ammonia escape in the case of non-uniform distribution of NOx concentration in flue gases at the inlet of SCR deNOx reactor. Compared with the uniform ammonia injection method, the partition ammonia injection makes NOx removal rate increase by 11.5 percent points, while ammonia consumption is reduced by 5 kg/h, and ammonia escape is declined by 77.5%. According to the estimation based on the relationship of temperature and concentration, if the difference of highest and lowest temperature in the same cross-section of the reactor inlet is more than 30 ℃ in the case of uniform ammonia injection，the partition ammonia injection method should be taken into consideration.

DISCUSSION ON DUST ACCUMULATION IN CONTINUOUS REFORMING UNIT

Fan Qiang

2017, 48(5):  81-86. 

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In the operation of a continuous reforming unit with 0.6 Mt/a capacity of SINOPEC Gaoqiao Petrochemical Company, the reaction temperature drop of the first reactor was decreased, the amount of catalyst dust greatly increased, and the abnormal fluctuations of the level of catalyst in the upper part of the reduction zone and the reduction temperature in the lower part of the reduction zone occurred. The analysis shows that the accumulation of catalyst dust in the system is one of the important reasons, and the low material level of the reduction zone 45%-50% leads to the fluidization of the catalyst in the reduction zone and large amount of dust, which blocks the catalyst movement in the delivery pipe, resulting in catalyst missing at the top of the first reactor, short-circuiting of reaction materials and a significant temperature drop reduction. After taking corresponding technical measures, like increasing the material level of the reduction zone, strengthening the catalyst dust elution operation and adjusting the reactor temperatures, the production is leveled off and the temperature drop is gradually restored.

ANALYSIS OF DIESEL ENGINE OIL AFTER MACK T-11 ENGINE TEST

2017, 48(5):  87-90. 

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The analysis results of two diesel engine oils after Mack T-11 engine test show that during the Mack T-11 engine test, the soot particle size increases with increasing of the soot concentration. The poor soot dispersity leads to a significant viscosity increase of the oil and abrasive wear due to formation of larger soot particle through aggregation. The diesel engine oil needs high enough base number to neutralize the acids from the circulation of the exhaust gas in the Mack T-11 engine test with exhaust gas recirculation system.

EFFECT OF FRICTION MODIFIER ON FRICTION PERFORMANCE OF GASOLINE ENGINE OIL

2017, 48(5):  91-96. 

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The friction and wear behavior of GF-5 0W-20 engine oil, A5/B5 0W-30 engine oil with organic molybdenum FM or organic amine FM were measured by SRV friction and wear test machine and high frequency reciprocating rig (HFRR) under different conditions. The results were verified by engine torque test after addition of FM. The test results show that FM’s friction performance can be distinguished by SRV and HFRR; the addition of appropriate amount of FM can reduce the friction coefficient of gasoline engine, engine friction loss and torque, improve the fuel economy. The results of SRV and HFRR test are well consistent with the results of engine torque test.

DETECTION OF CORROSIVE SULFUR IN TRANSFORMER OIL BY DL/T285 TEST METHOD

2017, 48(5):  97-100. 

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The DL/T 285 method (the flat copper wrapped insulation paper method) was used to investigate the influence of the transformer base oils having different sulfur and aromatics content as well as common additives on potential corrosive sulfur measurement. The tests show that the detective results of potential corrosive sulfur for all base oils are non-corrosive, mainly no coloration changes of the copper wire and copper sulfide deposited on the insulating paper are found; however, the antioxidant addition has a certain effect on the test results, even if adding metal passivator; the phenolic antioxidant has an interference effect on the judgment for the results of corrosive sulfur by DL/T 285 method at higher temperature due to the reaction happens between additives and copper wire tested, leading to the appearance of blue and gray or purple and red stripes on the copper surface. When there is doubt about the analysis of the DL / T285 method, can use SEM-EDX elemental analysis to the flat copper wire used to determine if the corrosive element sulfur exists.

CHARACTERIZATION OF NITROGEN-CONTAINING COMPOUNDS IN SAUDI ARABIA (LIGHT) ATMOSPHERIC RESIDUE

2017, 48(5):  101-106. 

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The molecular structures of nitrogen-containing compounds in the atmospheric residue from Arabian light crude was determined by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The ESI FT-ICR analysis indicates that the highest relative abundance of basic and neutral compounds is N1 class species. The neutral N1 class species are functional groups centered on pyrrole ring. Among of them, benzocarbazole and dibenzocarbazole is predominant. The basic N1 nitrogen compounds are functional groups of pyridine derivative compounds. Compared with the neutral N1 class species, the distribution of basic nitrogen compounds is more uniform.

EVALUATION OF OXIDATION STABILITY OF DIESEL FUEL BY ROTATING OXYGEN BOMB METHOD

2017, 48(5):  107-112. 

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The current method SH/T 0175 is not suitable for fast and simple evaluation of diesel fuel oxidation stability due to complex operation and long test period. A new fast way for the diesel oil oxidative stability is suggested based on the rotating oxygen bomb. The factors affecting repeatability and distinguishability are studied through single factor analysis and orthogonal experiments. The optional experiment conditions are screened out: 100 ℃, 800 kPa of oxygen pressure, 5 mL water, 40 g sample and 3.0m copper wire. The mathematical model to predict the total insolubles of diesel using the data of oxidation induction period and oxidation termination time are established. This method can be used to evaluate the oxidation stability of diesel fuel.