Table of Content

12 November 2014, Volume 45 Issue 11

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IMPACT OF La AND Ce ON NAPHTHA SULFUR REDUCTION OF VOx CATALYST DURING FCC PROCESS

2014, 45(11):  1-6. 

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In order to reduce the destruction impact of vanadium oxide on cracking component in FCC catalyst, the composite oxides containing vanadium, rare earth or alkaline earth metal were prepared respectively. The structures of composites were characterized by XRD, DTA, TPR and temperature-programmed surface reaction（TPSR-MS）. The mechanism of thiophenic sulfur removal was studied. The results indicate that lanthanum, cerium or Mg can react with vanadium to form a high melting point complex oxide: LaVO4, CeVO4 and MgV2O6, respectively. It is found by TPR that LaVO4 and CeVO4 can increase the reduction temperature of vanadium oxide, indicating the activity decline of the lattice oxygen. The results of TPSR-MS demonstrate that the main reaction for thiophene and cyclohexane on complex oxides (CeVO4 and LaVO4) is oxidation and dehydrogenation, respectively. TPSR-MS results show that the addition of magnesium in rare earth vanadates can significantly increase the conversion rate of thiophene. The heavy oil MAT results show that the catalyst containing 10% La-Mg-V can reduce the sulfur in naphtha by 67.2%.

DEVELOPMENT OF DECREASING NOx EMISSION ADDITIVES FOR FCC FLUE GAS

2014, 45(11):  7-12. 

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Reducing NOx emission additives for FCC flue gas (RDNOx，types I and II) were developed. RDNOx-I, a non-noble metal additive, is used to reduce NOx emission through catalyzing the reaction of NOx reduction. RDNOx-II, a noble metal additive, is used to substitute Pt based CO promoter, as it can promote CO combustion and decrease NOx formation at the same time. RDNOx-I and II can be used separately or simultaneously. The evaluation results show that when 0.5%-0.9% of RDNOx-II and 2-4% of RDNOx-I are applied, NOx emission in flue gas is reduced by about 50%-64%, while no negative influence on FCC product distribution is observed.

EFFECT OF CALCINATION TEMPERATURE OF SUPPORT ON PERFORMANCE OF CARBON RESIDUE REDUCTION OF HYDROGENATION CATALYST

2014, 45(11):  13-17. 

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The effect of calcination temperature of support on physical structure and the performance of catalysts was studied. The support and catalysts were characterized by BET, TPR and TEM techniques. The carbon residue reduction (HDCCR) activity of hydrogenation catalyst was conducted using an autoclave. It is shown that with increasing calcination temperature, specific surface area of the support decreases, mean pore size enlarges, the number of –OH group on the support surface decreases，which weakens the interaction between metal and support. It is found that the calcination makes the structure of MoS2 slab change. With increasing calcination temperature, the slab size becomes larger, leading to a lower dispersion. The HDCCR activity of the catalyst reaches the best when the support is calcined at 600℃.

ACTIVITY EVALUATION MODEL FOR S Zorb SORBENT AND ITS APPLICATION

2014, 45(11):  18-22. 

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The sorbent activity index and potential activity index were presented and defined, used to evaluate the activity of S-Zorb sorbent. These indexes were organic combination of the phase content of sorbent, operation parameter and sulfur contents of both raw oil and product. Based on the industrial data, a correlation model was established which combined indexes with desulfurization ability of unit. The correlation model can evaluate whether the activity of sorbent meets the special requirement of desulphurization. Conversely，the reasonable sorbent activity index can also be deduced according to the requirement of desulphurization. Furthermore, these indexes can be used to calculate the replacing amount of fresh sorbent needed and to guide the regeneration operation. The correlation model is successfully applied in a 900 kt/a S-Zorb industrial unit of Jinan Company, SINOPEC.

PREPARATION OF HIGH METAL CONTENT Ni-W CATALYST AND PERFORMANCE FOR COMPETIVITE CATALYTIC REACTION

2014, 45(11):  23-28. 

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A series of composite Ni-W oxides with different ratios were synthesized. The high metal content NiW catalysts were prepared with these NiW mixed oxides as precursors and characterized by XRD, N2 adsorption-desorption, SEM and HRTEM. The competitive catalytic reactions of the catalysts were tested with a mixed model compound (naphthalene, quinoline and dibenzothiophene) to study the performance of hydrodearomatization, hydrodenitrogenation and hydrodesulfurization, respectively. The results show that the catalysts with mesoporous contain NiWO4 and WO3?0.75H2O phases, and the stacking layers of the WS2 slab on the sulfided high metal NiW are 2 to 6 with the slab length in the range of 3 to 10 nm. The reaction results reveal that high metal NiW catalyst exhibits high catalytic activity toward the conversion of quinoline and dibenzothiophene, the conversions are both more than 90%, while the conversion of naphthalene is relatively low.

PREPARATION OF Pd/ CoSAPO-11 CATALYST AND ITS n-BUTYLENE ISOMERIZATION PERFORMANCE

2014, 45(11):  29-32. 

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Double atom Si and Co-substituted AlPO-11 zeolite, CoSAPO-11, was synthesized in situ by hydrothermal method and the Pd/ CoSAPO-11 catalyst was then prepared by incipient wetness method using PdCl2 solution. The isomerization performance of n-butylene on the prepared catalyst was investigated at different temperatures and space velocities. Compared with the traditional commercial Pd/γ-Al2O3, Pd/CoSAPO-11 catalyst exhibits better n-butylene isomerization performance. The results show that at the optimal conditions: 400℃, 5.0 MPa and velocity of 2-4 h-1. The selectivity to isobutylene of the Pd/ CoSAPO-11 catalyst is up to 82.9%-93.1 % with the yield of 31.7%-34.5 %.

DEVELOPMENT OF HYDROISOMERIZATION CATALYST FOR LUBE BASE OIL PRODUCTION FROM PARAFFINIC FEEDSTOCKS

2014, 45(11):  33-37. 

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A hydroisomerization catalyst was developed based on AEL zeolite. n-C12 and the hydrotreated 650SN furfural refined oil were used as feeds, respectively, to evaluate the hydroisomerization performance of the catalyst. The results show that the catalyst has better hydroisomerization activity and selectivity. When processing 650SN, the high quality group API III lube base oil is produced. The pour point of the base oil reaches -21℃, 6℃ lower than the reference catalyst, and heavy base oil yield reaches 62.79%, 5.55% higher than the reference one, which indicates that the hydroisomerization performance of the catalyst is better than the reference catalyst.

ETHYLENE HOMOGENEOUS POLYMERIZATION CATALYZED BY NEW TYPE BUTANEDIONE TITANIUM COMPLEX

2014, 45(11):  38-43. 

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A new type double imine ligand was synthesized by the addition condensation reaction of butanedione carbonyl group and O-aminophenol amino. The butanedione o-aminophenol titanium complexe (titanium complex) was prepared by treatment of TiCl4 with the ligand. Activated by the methylaluminoxane (MAO), the performance of the complex for ethylene homopolymerization in toluene solvent was evaluated. The catalytic activity of the titanium complex reaches 1.53×106 g PE/(mol?h) at the reaction conditions: 40℃，0.8MPa，reaction time of 45 min and the mole ratio of [MAO]/[Ti-complex] of 4500, The high linearity and crystallinity PE product has a relative molecular weight higher than 4.5 x 105 and a high melting point (> 130 ℃).

STUDY ON CHANGES OF HYDROCARBONS COMPOSITION OF HYDROCRACKING TAIL OIL

2014, 45(11):  44-47. 

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The changes of hydrocarbon composition of hydrocracking tail oil in different reaction stages are discussed using Saudi Arab VGO as a feedstock. Paraffin content of hydrocracking tail oil increases with conversion rate rising. The proportion of paraffins in tail oil remains basically no change when the conversion rate is lower than 58.7% and decreases when the conversion rate is higher than 58.7%. Analysis suggests that ring-opening of cyclic hydrocarbon, off side chain reaction and the reaction products into the light component are the main causes for the changes. Therefore, the paraffin content of tail oil increases with the improvement of cyclic hydrocarbon ring opening ability of the catalyst.

METAL DEPOSITION ON WELL-DEFINED AND UNIFORM PORE- STRUCTURE CATALYST IN RESIDUUM HYDRODEMETALLIZATION

2014, 45(11):  48-53. 

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The effect of catalyst pore diameter on the metal deposition distribution and hydrodemetallization conversion of residue oil were investigated over well-defined and uniform pore-structure catalysts. The hydrodemetallization of Saudi Arabia vacuum residue was conducted in a batch stirred autoclave at 400 ℃,10 MPa H2 pressure. Samples of the used catalysts were characterized by SEM and EDX to elucidate the deposition distribution of Ni and V in catalyst pellets. The contents of Ni and V in the hydrodemetallized oil were measured by AES-ICP. The results show that the Ni and V metal deposition profiles are uniform on the two catalysts with pore size larger than 47 nm, indicating that the reaction is controlled by chemical reaction rather than by internal diffusion of reactants. When the catalyst pore size is smaller than 17 nm, the maximum amount of metals deposition appears at the entrance of the catalyst pellets, and decreases along the axial toward the center of the catalyst pellets, indicating the HDM reaction is diffusion control process. The deposition profiles of Ni and V are different from each other, showing that the ratios of reaction rate to the diffusion rate are different for the two metal compounds.

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STUDY ON CHARACTERISTICS OF GAS-SOLIDS FLOW IN DIAMETER-ENLARGED SECTION OF A NOVEL RISER REACTOR

2014, 45(11):  54-59. 

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Axial and radial solid concentration profiles inside a novel riser reactor featured by bottom enlargement were investigated and the characteristics of gas-solid microflow behavior in the diameter-enlarged section were analyzed in a cold model apparatus. The results show that the solid concentration distributions are characterized by two regions: dense bottom region and dilute upper region with a reduced radial non-uniformity index along the axial direction. Compared with the bottom region of the conventional riser, higher solid concentration and intermittency index with more uniform radial distribution in the diameter-enlarged section are observed, demonstrating a stronger gas-solid interaction and a smaller radial gradient of the gas-solid microflow behavior. The gas-solid microflow behavior inside the diameter-enlarged section performs similarly to that in turbulent flow and is significantly affected by the structure of the reactor. The fluctuations of solid concentration in the diameter-enlarged section are characteristic of large amplitude and high frequency, and the distributions of dilute phase and dense phase are relatively uniform, which intensifies the gas-solid contacting and mixing process.

OIL ADSORPTION AND REUSE PERFORMANCE OF MULTI-WALLED CARBON NANOTUBES

2014, 45(11):  60-64. 

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Carbon nanotubes (CNTs) arouse widespread attention as a new type of adsorbent due to their outstanding adsorption ability. The adsorption capacity and reuse performance of multi-walled carbon nanotubes (MWCNTs) for gasoline, kerosene, diesel and heavy diesel were tested in this work. The effect of machinery extrusion method and incineration method on the adsorption capacity and reuse performance of MWCNTs were investigated, respectively. The results show that with the increase of repeated use, the oil adsorption abilities of MWCNTs decrease and tend to stabilize gradually. Compared to the burning method, mechanical extrusion method is easy to destroy the initial space structure of the MWCNTs, thus lowering the adsorption capability when reuse. It is found that the oil adsorption capacity of the extruded MWCNTs increases with the increase of carbon chain length of the oil; While for the incinerated MWCNTs, the oil re-adsorption capacity decreases because the space structure and adsorption site are more easily destroyed or covered during the process of incineration due to the deposition of coke on the surface of MWCNTs.

DEVELOPMENT OF SELECTIVE CATALYTIC CRACKING TECHNOLOGY FOR MAXIMIZING CATALYTIC PROPYLENE AND ITS COMMERCIAL APPLICATION

2014, 45(11):  65-69. 

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Based on the new findings of the primary cracking of heavy oil and the secondary cracking of middle streams, a MCP technology (Maximizing Catalytic Propylene from heavy oil) was developed. The first industrial trial was conducted in a commercial-scale demonstration unit of MCP with capacity of 250Kt/a from an existing ARGG unit modification. The results of industrial calibration of MCP technology show that when the atmospheric residue of Jiangsu crude oil is used as the feedstock, yields of propylene and isobutylene are 17.05% and 5.51%，respectively. RON of gasoline and  cetane index of LCO are 94.6 and 30, respectively. The total liquid yield is 80.23%. Compared with ARGG, the yield of propylene and isobutylene increases 8.09% and 2.52%，respectively，while the coke reduces 2.03%. The unit of MCP has stably run for nearly 3 years with good economic and social benefits.

KEY PARAMETERS IN PRODUCTION OF NATIONAL PHASE V GASOLINE BY SELECTIVE HDS PROCESS

2014, 45(11):  70-73. 

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To produce national phase V gasoline from FCCG, the key operation parameters of the units in the selective hydrodesulfurization process were strictly regulated as a whole, like cutting point, fractionation precision, sulfur content of light gasoline from alkali extraction unit, sulfur content of heavy gasoline from hydrodesulfurization unit. The process adopts the RIPP`s selective HDS catalyst made by the regulation technology (RSAT). The optimal operation conditions are: cutting point is 50-60 ℃ with a mass ratio of 1:4 (light/heavy), mercaptan sulfur in light gasoline from alkali extraction unit is close to nil, sulfur content of heavy gasoline hydrodesulfurized is less than 10 μg/g. The sulfur content of the mixture of alkali extracted light gasoline with selective hydrodesulfurized gasoline is less than 10μg/g. Based on above conditions, the sulfur content can be reduced from 700-853 μg/g in feed to 8-9 μg/g in the product and the gasoline octane number loss is 1.4-1.5. The national phaseⅤgasoline is produced. The successful experience in the production lays a firm foundation for the next step using RSDS-III technology.

IMPROVING LIQUID YIELD OF TAHE OIL BY ATOMSPHERIC FLASH-SOLVENT DEASPHALTING COMBINED PROCESSING

2014, 45(11):  74-79. 

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Tahe crude is characterized by its high content in sulfur, acid value, conradson carbon residue, asphaltenes, metals and low yield of light distillates. Two combined processes for Tahe crude oil，atmospheric flashing-solvent deasphalting process and atmospheric distillation-delayed coking process were compared to see which one is better for more liquid yield. The results show that the total liquid yield can reach 78.77% by the atmospheric flashing-solvent deasphalting combined process, 9.47% more than the atmospheric distillation-delayed coking process (69.30%). The liquid distillations with high quality from the former process can be used as catalytic cracking or hydrotreating feeds. Meanwhile, the corrosion of petroleum acid existing in atmospheric and vacuum distillation can be retarded as the operating temperature of atmospheric flashing-solvent deasphalting combined process is far lower than the temperature where the corrosion of petroleum acid is seriously occurred. In aspect in increasing total liquid yield, improving liquid oil properties and retarding corrosion, the atmospheric flashing-solvent deasphalting combined process is superior to the compared process.

FACTORS AFFECTING OPERATION PERIOD OF COKING FURNACE AND CORRESPONDING MEASURES

2014, 45(11):  80-84. 

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By analysis of the operation data it is found that the asphaltene and salt content are the main factors influencing the heating furnace operation period for our coking unit and that once the asphalt content is more than 18% and the salt content is higher than 10 mgNaCl/L, the operation cycle of the heating furnace is sharply shorten, the shortest one is about 2 months. By strengthening raw material control, establishing early warning value, timely adjusting circulation ratio and reaction temperature as well as adjusting the gas injection rate, the cycle can be extended to 4 months. The operation practice proves that as long as the asphalt content is not greater than 18% with the salt content less than 10 mg NaCl/L, the heating furnace operation cycle can be prolonged to 5 ~ 6 months.

LIGHT HYDROCARBON RECOVERY BY AMMONIA REFRIGERATION TECHNOLOGY

2014, 45(11):  85-88. 

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The light hydrocarbon recovery process by the use of ammonia refrigeration technology in Shenhua Erdos CTL Branch Co. was introduced. The operation practices indicate that the re-adsorption tower and ancillary facilities can be omitted from the original classical recovery process consisting of adsorption tower, re-adsorption tower, desorption tower and stabilizer when the ammonia technology is used and the temperature at the top of adsorption tower is controlled at 18.4℃. The C3+ in dry gas is only 1.96% (v). While C5+ in LPG is 0.07% (v), which meets the national standard of not more than 3.0% (v). The C3 yield reaches 94.0% (v), higher than the classical light hydrocarbon recovery process. In addition, raw material and liquid ammonia are from other units which can reduce the production cost and is good for resource optimization and integration between units.

FRETTING WEAR AND SELF-REPAIRING PROPERTIES OF C45 STEEL UNDER LUBRICATION OF LITHIUM GREASE CONTAINING ATTAPULGITE POWDER

2014, 45(11):  89-94. 

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Different mass fractions of organic modified attapulgite powder scattered into the base oil as additive were added into lithium grease during the 3# grease preparation. The amount of attapulgite and the friction reduction, anti-wear and self-repairing properties of the lithium grease were evaluated using a SRV friction wear machine. As a comparison, the tribological properties of base lithium grease were also investigated. Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) were employed to analyze the worn surface topography and the elements on the worn surface. The results show that after adding different amount of modified attapulgite into lithium grease, the friction coefficient and the wear rates of the grease decline in different extent. When 0.8% attapulgite is added, the results are the best. The worn surface lubricated with grease containing attapulgite is smoother more than that lubricated with blank one and there were no obvious wear characteristics. There is a repairing film formed on the worn surface, which is different from substrate material and contains C, Fe, Si, Mg, O and Al elements.

PREPARATION OF ULTRAFINE POWDER BENTONITE AS THICKENING AGENT BY WET BALL-MILLING

2014, 45(11):  95-99. 

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The orthogonal experiment was conducted to optimize the wet ball milling process conditions for ultrafine bentonite powder preparation. The analyses of particle size, Fourier transform infrared spectroscopy (FI-IR), X-ray diffraction (XRD) and thermal properties (DSC-TG) were performed for the prepared ultrafine powder. The results show that the particle sizes of bentonite powder prepared is among 200 to 500 nm and the interlayer spacing is expanded from 2.07nm to 2.25 nm under the best wet ball-milling conditions: milling ball bulk density of 70%, milling time of 7 h, slurry concentration of 20%. The bentonite lattice structure still maintains a good character though slight distortion occurs. The penetration test of ultrafine bentonite grease indicates that the ultrafine powder with smaller particle size and good uniformity has excellent thickening ability.

COMPONENTS ISOLATION AND IDENTIFICATION OF MEDIUM /LOW TEMPERATURE COAL TAR

2014, 45(11):  100-104. 

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The VGO fraction (360~480℃) of middle/low temperature coal tar was prepared by vacuum distillation. The fractions were extracted by heptane solution to isolate the soluble components that were further separated into four components by column chromatographic separation method using silica gel as adsorbent. Petroleum ether, toluene, ethanol, toluene, ethanol for lotion were used. The best column chromatography conditions were determined by contrasting the recovery ratio, difficulty of component flushing and the split points of elution experiments. Furthermore, the components were identified by means of NMR and elements or molecular weight determination. The results reveal that the contents of saturates, aromatics, polar components and C7-asphaltene in VGO fraction were 13.28%, 36.10%, 33.15%, 18.21%, respectively and 6.00% of VGO fraction is paraffin, 7.25% is cycloparaffin and 36.12% is arene. In addition, the polar components and C7-asphaltene are both constituted by polycyclic aromatic hydrocarbons and large molecule with few short side chains. It is the complexity of these soluble components that is the principal factor for difficulty in the conversion to light fraction of coal tar.