Table of Content

12 April 2017, Volume 48 Issue 4

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EFFECT OF QUINOLINE COMPOUNDS ON NITROGEN DISTRIBUTION IN CATALYTIC CRACKING PRODUCTS

2017, 48(4):  1-5. 

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The effects of the mass ratio of catalyst to oil and the total acid content of catalyst on the conversion and nitrogen distribution of Daqing VGO and its mixture with quinoline were investigated respectively at 500-560 ℃ in a fixed fluidized bed reactor. The results show that quinoline exhibits an adverse influence to the reactivity of Daqing VGO, resulting in more nitrogen in gasoline and diesel than the single VGO feed. Alkylation and cracking reactions are the main pathways of quinoline during catalytic cracking. Aniline, as the middle product, can further crack into ammonia with the increase of temperature. The competitive adsorption of basic compounds can be weakened by raising mass ratio of catalyst to oil, resulting in decrease of nitrogen content in liquid products. The conversion of quinoline is significantly enhanced as the catalyst total acid content increases and more nitrogen is concentrated in coke.

EFFECT OF SURFACE ENHANCED HEAT TRANSFER ON FISCHER-TROPSCH SYSNTHESIS PERFORMANCE IN FIXED-BED REACTOR

2017, 48(4):  6-11. 

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The boiling properties of smooth tube, sintered coated porous reactor tube and mechanically fabricated porous surface tube, and the effects of reactor structure parameters on boiling heat transfer were investigated in a pool boiling device. The effects of surface enhanced heat transfer on Fischer-Tropsch synthesis were studied in a fixed-bed reactor with three kinds of tubes, respectively. The results in pool boiling show that the heat transfer properties in enhanced surface tubes are better than the plain tube, resulting in lower incipient boiling superheat and earlier boiling. The heat transfer performance is different for sintered coated porous tube and mechanically fabricated porous surface tube at different heat flux ranges, but both can improve the F-T performance. However, the influence of heat transfer enhancement is not obvious for sintered coated porous reactor tube under lower CO conversion rate. With the increase of heat flux and improvement of heat transfer performance, the distribution of catalyst bed temperature becomes more even and the mechanically fabricated porous surface tube shows more obvious promotion for heat transfer. Under same reaction conditions, higher CO conversion and C5+ selectivity are observed. The mechanically fabricated porous surface tube could get higher wall heat transfer coefficient than that of sintered coated porous reactor tube.

STUDY ON MOLECULAR SIMULATION AND PHASE EQUILIBRIUM FOR REMOVING DMDS IN MTBE BY EXTRACTIVE DISTILLATION

2017, 48(4):  12-18. 

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The polarizable continuum model (PCM) calculation was used to explore the interaction between extractant and sulfide. In addition, Ellis equilibrium distillation experiments were performed for measuring the vapor-liquid equilibrium data of sulfide dimethyl disulfide (DMDS) in methyl tert-butyl ether (MTBE) and various extractants solutions. At the same time, the basic properties of extractants were measured and compared for screening the optimal solvent. The results of quantitative calculation indicate the following order of the interactions between different extractants and DMDS: dimethyl sulfoxide (DMSO) > sulfolane (SULF) > dimethyl formamide (DMF) > N-methyl-2-pyrrolidone (NMP) > diethylene glycol (DEG). The Ellis distillation experiments show the selectivity order of various extractants as: DMSO > SULF > DMF > NMP > DEG. The molecular simulation results are consistent with the experimental findings. As a result, DMSO can be considered a suitable solvent for MTBE extractive distillation desulfurization. Furthermore, an empirical correlation was built to reveal the equilibrium behaviors under different ratios of extractant/MTBE. This study can provide the necessary data and lay a theoretical foundation for the design and development of MTBE extractive distillation desulfurization process.

PREPARATION AND DEMULSIFICATION PERFORMANCE OF MULTIBRANCHED DEMULSIFIER

2017, 48(4):  19-23. 

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Starting from ethylenediamine and methacrylate, 2.0 G starburst dendrimers were synthesized by twice Michael reaction and amidation. The starburst dendrimers were then grafted by reaction of epoxy ethane/epoxypropane co-polyether with hydroxyl value of 60 mgKOH/g and epoxy chloropropane, a chain extender, to prepare a new type of multi-branched demulsifier. The 2.0G starburst dendrimers were characterized by IR and potentiometric titration. The demulsifier were characterized by IR and the demulsification performance was evaluated. The demulsification results for a simulated crude oil emulsion of PL19-3 WHPD platform show that the dehydration ratio can reach 90% at 50 ℃，dosage of demulsifier 90 mg/L and dehydration time 30 min. Compared with the existing demulsifier under simulated field conditions, the new demulsifier exhibits a better performance. The oil content in the separated water is 20.3 mg/L, and the water content in the oil is below 0.5%.

EFFECTS OF COMBINATION OF COLD FLOW IMPROVERS ON DIESEL SOLIDIFICATION POINT DEPRESSION

2017, 48(4):  24-28. 

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Combination of solidification point depressants is one of the effective means to improve low temperature properties of diesel fuel. In this paper, three kinds of solidification point depressants and their combinations with different ratios were used to investigate the effect on the reduction of solidification point of 0# diesel fuel from the refinery of Jilin Petrochemical Company. Cold Filter Plugging Point (CFPP) and differential scanning calorimeter (DSC) were used to evaluate the solidification point reduction effect and clarify the mechanism of wax crystallization at low temperature. The results indicate that there is a better synergistic effect in the combination use of di-n-alkyl fumarate-vinyl acetate copolymer (PFVA) and polyethylene-vinyl acetate (EVA) and paraffin crystal dispersant 2-(hydrogenated tallow) phthalic acid amide (Tab). The CFPP can be reduced by 19 ℃ at the sum dose of 500 ug/g with the ratio of PFVA 46%: EVA 46%: Tab 8%. Both of the peak temperature for wax crystal precipitation and the absolute value of wax crystal phase change heat ΔH is reduced. The combinations of solidification point depressants can delay the wax crystal precipitation, thus improves the low temperature fluidity of diesel fuel.

SYNERGISTIC EFFECT OF ULTRASONIC AND VISCOSITY REDUCTION INTENSIFIER FOR HEAVY OIL AT ROOM TEMPERATURE

2017, 48(4):  29-35. 

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Ultrasonic was applied with viscosity reduction intensifier to reduce the viscosity of heavy oil under the conditions of not adding water. The SARA of heavy oil before and after treatment was analyzed. The effect of intensifier concentration, reaction time and ultrasonic power on the viscosity reduction of heavy oil was studied. The changes in viscosity and flow property of heavy oil before and after treatment and the recovery of viscosity were analyzed by MCR 302 rheometer. The infrared spectroscopy and gas chromatography was used to analysis the structure changes. The experimental results show that the intensifier concentration has the biggest effect on viscosity reduction of heavy oil, followed by reaction time and ultrasonic power. The higher the intensifier concentration, the better the effect for viscosity reduction. With the increase of the treatment time and ultrasonic power, the effect for viscosity reduction increases and then decreases slightly. There is a synergistic effect between ultrasonic and intensifier for the process, which leads to chain scission of long chain macromolecules, aromatic rings and other heteroatoms, hydrogenation and ring opening reactions. The combination use of ultrasonic and intensifier can reduce the viscosity of heavy oil under normal temperature conditions, improve the flow properties and the quality of heavy oil.

DEVELOPMENT AND INDUSTRIAL APPLICATION OF DIESEL HYDROUPGRADING PROCESS FOR IMPROVING COLD FLOW PROPERTIES

2017, 48(4):  36-40. 

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In order to improve the cold flow property and cetane number of diesel, a new diesel hydroupgrading process and RHC-130 catalyst were developed by SINONEC Research Institute of Petroleum Processing. The results show that different types of low solidification point diesels which meet the national V diesel standard under mild conditions can be produced, indicating a good adaptability of RHC-130 catalyst to straight run gas oil, LCO, coker gas oil and their mixed oils. The large improvements in solidification point, cetane number, and yield of diesel can be obtained. The industrial application demonstrates that the－35#, －20# or －10# diesels can be produced by adjusting reaction temperature.

MODIFICATION OF ALKYLATION CATALYST OF DIPHENYLAMINE AND ITS APPLICATION

2017, 48(4):  41-46. 

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In view of the problems of large amount of catalyst used and waste residue with lots of product and pollution in diphenylamine alkylation process, the modification of the clay atalyst was performed, the operation conditions were determined. By use of the modified catalyst, the products with similar physicochemical and antioxidant performance to industrial product are obtained. The results show that the improved catalyst can meet the need of existing process and reduce the usage amount of catalyst, resulting in less pollution, higher yield and benefit.

APPLICATION OF HYDROGENATION TECHNOLOGY OF C5 RAFFINATE OIL MIXED WITH NON- AROMATIC GASOLINE

2017, 48(4):  47-51. 

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The process for the selectively hydrogenation of C5 raffinate oil mixed with non-aromatic gasoline was tested. The effect of reaction conditions such as the feed dilution ratio, reaction temperature，reaction pressure, liquid hourly space velocity(LHSV) and volume ratio of hydrogen to oil were investigated. The optimized conditions are: ratio of C5 raffinate oil/non aromatic gasoline（1：5）-（1：7）, the average temperature 120-140 ℃，reaction pressure 4.0-5.0 MPa , LHSV 1.0-4.0 h-1，volume ratio of hydrogen to oil 200-400. Under these conditions, the diolefins in the product were less than 0.1%. The long run experiment proves that the catalyst has a good performance in activity and stability.

EFFECT OF HYDROTREATED GAS OIL ON FCC PRODUCT DISTRIBUTION IN WUHAN REFINERY

2017, 48(4):  52-56. 

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The operation of the 1.8 Mt/a gas oil hydrotreating unit and the effect on the FCC product distribution in SINOPEC Wuhan Company as well as the problems using the mixture of LCO and gas oil as the unit feed were introduced. The measures for solving the problems were suggested. The RVHT technology and related catalysts developed by SINOPEC Research Institute of Petroleum Processing were adopted to process the mixed feed of CGO and VGO. The sulfur and nitrogen content of the hydrotreated effluent is less than 1 000 μg/g and 1 200 μg/g, respectively. Compared with the gas oil without hydrotreating, in the cases of feeds containg hydroteated gas oil of 89.50% in 1# FCC unit and 65.53% in 2# FCC unit, the gasoline yield increases 3.590% and 1.905%, respectively, though the yield of LCO is not improved significantly, however, the yield of slurry, coke and dry gas decreases. When VGO mixed with FCC LCO is used as hydrotreating unit feed, the hydrogen consumption and the reaction temperature rise markedly, while the effect on the catalysts reactivity and running cycle is less. The fluctuation of system pressure during operation is mitigated by increasing return hydrogen from circulation line and thereby decreasing the hydrogen/oil ratio in reactor inlet.

COMMERCIAL APPLICATION OF WET FLUE GAS DESULFURIZATION TECHNOLGY IN 3.5 Mt/a RFCC UNIT

2017, 48(4):  57-60. 

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In order to get clean regenerated flue gas with little SO2 and PM，CNPC Guangxi Petrochemical Company built a new WGS unit for 3.5 Mt/a RFCC Unit. The WGS demonstration test shows that the SO2 and PM emissions achieve the discharge standards for environmental protection，the salty water can meet the design requirement and sewage sludge can be landfilled directly，the material balance is reasonable, the key operation parameters meet the design requirements, the energy consumption is slightly lower than the design value, the use of WGS has no effect on the catalytic cracking unit. The WGS technology has advantages of simple operation and can run for a period of long time.

PROBLEMS AND TECHNICAL TRANSFORMATION OF DELAYED COKING UNIT

2017, 48(4):  61-64. 

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This paper analyzed the operation problems of 1.2Mt/a delayed coking unit in PetroChina Lanzhou Petrochemical Company and introduced the results after technical transformation. The problems in existing unit included: (i) high content of oil, COD and suspended matter in coke quench sewage, which was unable to reuse as a cold coke cutting water; (ii) coke fines in the sour water from fractionator overhead, and in coking gasoline and diesel, which influence long period operation of the downstream unit; (iii) design defects in process interlock of heating furnace, leading to an invalid use. To solve these problems, a cold coke sewage treatment system and a coke powder removing system were added. Then the treated cold coke sewage can be reused and the influence of coke fines on the operation for downstream unit is reduced; the interlocking mode of heater furnace was changed from“one-out-of-one”to “two-out-of-three”, and is successfully applied after transformation.

COMMERCIAL APPLICATION OF SULFUR TRANSFER ADDITIVE ON PARTIAL COMBUSTION FCC UNIT

2017, 48(4):  65-68. 

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The new generation sulfur transfer additive RFS09 was applied on the partial combustion FCC unit in PetroChina Guangxi Petrochemical Company. The results show that when the average sulfur content in feedstock is 0.338% and RFS09 is added at 5% of the fresh catalyst, SO2 in the flue gas from CO boiler is less than 850mg/m3, which meets the requirment of specifications. The SO2 removal rate is higher than 50% , calculated based on the SO2 emission about 1 800 mg/m3 without additive. In addition, during the trail of RFS09, the yields of total liquid products, slurry and coke change little. The particle concentration in flue gas remains constant and even decreases slghtly, and solid content of slurry also remains constant. Key Words: FCC; partial burn regeneration; flue gas; sulfur transfer additive

EFFECT OF LOADING POSITION OF BULK CATALYST IN REACTOR ON ULTRA-DEEP HYDRODESULFURIZATION

2017, 48(4):  69-72. 

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The combination use of the bulk catalyst developed by SINOPEC Fushun Research Institute of Petroleum & Petrochemicals and conventional diesel hydrotreating catalyst increases the HDS activity. The effect of loading positions of the bulk catalyst on HDS was tested. The results show that the bulk catalyst loaded at the upper part in the reactor (lower reaction temperature zone) is helpful to removal sulfur for diesel feeds with low processing difficulty; while for diesel with medium/higher processing difficulty, the lower part of the reactor (high temperature reaction zone) is better for bulk catalyst loading. The work provides a basis for the combination loading of bulk catalyst and conventional hydrotreating catalyst to improve the diesel ultra-deep HDS performance.

PREPARATION OF MESOPOROUS CARBON-BASED SOLID ACID AND ITS APPLICATION IN BIODIESEL PRODUCTION

2017, 48(4):  73-77. 

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Mesoporous carbon-based solid acid catalysts were prepared by carbonization-sulfonation method with SiO2 as a template and sucrose as carbon source. The catalysts were characterized by acidimetric analysis, BET, XRD, FT-IR and SEM. The effects of carbonization temperature and sulfonation temperature on the catalyst performance were investigated, then the prepared catalysts were used in transesterification reaction between soybean oil and methanol, and the effects of reaction conditions and the content of fatty acids in the feed were studied. The results show that the optimum preparation conditions of the catalysts for carbonation and sulfonation temperature were 400 ℃ and 170 ℃, respectively; the yield of biodiesel for transesterification reaction between soybean oil and methanol reached 95.94% under the optimum conditions of molar ratio of methanol to soybean oil 30, reaction time 4 h and catalyst dosage of 8% (accounted for the percentage of soybean oil ); The yield of biodiesel is still over 85.46% after the catalyst was reused for five times, ,indicating the good stability of the catalyst. The fatty acids in the feedstock have a negative effect on the performance of the catalyst. However, in the case of 15% fatty acid in the raw material, the biodiesel yield is still over 90%.

EFFECT OF PREPARATION METHOD ON CATALYTIC ACTIVITY OF Ce0.8Zr0.2O2 CATALYSTS FOR SOOT COMBUSTION

2017, 48(4):  78-82. 

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A series of Ce0.8Zr0.2O2 catalysts were prepared by citric acid sol-gel method，low temperature co-precipitation method，high temperature co-precipitation method，hydrothermal method and thermal decomposition method. The structures, surface morphologies, oxygen storage capacities, and redox abilities of all catalysts were characterized by XRD, BET, SEM, thermogravimetric analysis, H2-TPR and O2-TPO. Potentials of the catalysts in the soot oxidation were evaluated by TPO analysis. The effects of preparation methods on the performance of catalytic soot combustion were investigated. The results indicate that the cerium zirconium solid solution with cubic fluorite structure is formed in all samples by all of the above methods. Sol-gel method is in favor of oxygen storage capacity and performance improvement; hydrothermal method helps improve the catalyst specific surface area; the catalyst prepared by thermal decomposition method has a flat surface structure which enhances the mechanical strength. However, the catalyst prepared by co-precipitation is poor in oxygen storage capacity and catalytic activity due to the influence of the temperature during the preparation.

STUDY ON ALKYLATION PROPERTIES OF ZEOLITE BETA MODIFIED BY PHOSPHORUS AT NORMAL AND HIGH TEMPERATURE

2017, 48(4):  83-86. 

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The zeolite beta modified by phosphorus at normal and high temperature was characterized by thermogravimetric, NMR and acid analysis, and their alkylation performance for benzene with propylene was investigated. The analysis shows that after introduction of ammonium ion into zeolite beta at high temperature, an obvious peak appears at 220-230 ℃ in DTG curve, indicating the ammonium ions coming into the zeolite; and 31P MAS NMR and 27Al MAS NMR of zeolite shows two strong peaks at chemical shift -30.908 and 41.392, demonstrating the formation of tetracoordinated structure of P (4Al) and Al (4P); The modification leads more acid sites and stranger acid, proved by NH3-TPD analysis. The alkylation performance is improved significantly after modification of the zeolite at high temperature.

PREPARATION OF SPHERICAL ZSM-5 ZEOLITE CATALYST AND ITS APPLICATION IN MTA PROCESS

2017, 48(4):  87-91. 

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Spherical ZSM-5 zeolite catalysts were prepared by water column forming method. The samples were characterized by static nitrogen adsorption-desorption, strength tester and XRD and evaluated in the MTA reaction. The influences of binder type, binder proportion and post-treatment process on the properties of spherical ZSM-5 zeolite catalyst were studied. The results indicate that the alumina gel is the preferred binder, with the increase of amount of alumina gel，the strength of ZSM-5 zeolite catalysts improves. When dosage of alumina gel is 40% and after post-treatment with aluminum nitrate, the spherical ZSM-5 zeolite catalysts with pore volume of 0.34 mL/g, specific surface 282 m2/g and crushing strength 38 N are obtained. When it is applied to the MTA reaction with Zn, Ni as active component, the yields of liquid and aromatics and aromatics selectivity are all better than the extruded sample.

CHARACTERIZATION OF SULFUR COMPOUNDS IN LIQUID PRODUCTS FROM RESIDUE CONTACT CRACKING PROCESS BY COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY COUPLED WITH TIME-OF-FLIGHT MASS SPECTROMETRY

2017, 48(4):  92-98. 

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Sulfur compounds in liquid products from residue contact cracking process were characterized by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS), results showing that there were sulfur species identified such as phenyl alkyl sulfides, thiophenols, thiophenes, benzothiophenes, dihydro-benzothiophenes, dibenzothiophenes, naphthothiophenes, tetrahydro-dibenzothiophenes, benzonaphthothiophenes, phenanthrothiophenes, benzodithiophenes and thiopyrans. Based on group separation and tile effect in GC×GC-TOFMS, carbon number distribution characteristics of thiophenes, benzothiophenes and dibenzothiophenes in liquid products were studied, in addition, 15 individual molecules of C2-DBTs which got extensive concern in oil processing were determined and recognized. Combined with residue contact cracking process, it was found that micro-reactor activities of contact agents had evident influence on molecular species and carbon number distribution of sulfur compounds in liquid products from residue cracking, and to be specific, sulfur molecule species were similar in products from one residue on different contact agents, while contents and distribution mode of them varied a lot. As for carbon number distribution of sulfur compounds in liquid products, taking benzothiophenes (BTs) for example, low carbon number alkyl (C1-C3) BTs dominated in their homologues distribution when using strong agent, while relatively high carbon number alkyl (C4+) BTs dominated on weak agent.

ASPHALTENE DISPERSANTS AND INHIBITOR- A REVIEW

2017, 48(4):  99-108. 

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Asphaltene, the most polar and heaviest component in petroleum, is very easy to flocculate and precipitate, resulting in problems in petroleum storing, transporting and processing. Adding chemical additives is one of the most effective ways to reduce and control asphaltene precipitation. In this paper, the progress of asphaltene chemical additives in recent ten years was reviewed from the aspects of classification, structural features, mechanism and effect of chemical additives. Factors that affect the effect of asphaltene chemical additives were analyzed. Finally, selection and synthesis of asphaltene chemical additives were suggested.