Table of Content

12 March 2016, Volume 47 Issue 3

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INFLUENCE FACTORS OF PARA-XYLENE SELECTIVE ADSORPTION ON BaX-TYPE ZEOLITE

2016, 47(3):  1-4. 

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In order to achieve high para-xylene (PX) selectivity, pulse test was employed to evaluate the performance of BaX-type zeolite, the influences of the framework SiO2/Al2O3 molar ratio of X zeolite, Na+ exchange ratio and water content on the PX selectivity were investigated systematically. It was found that with the increasing of the framework SiO2/Al2O3 molar ratio from 2.01 to 2.53, the separation factors of PX to meta-xylene (βP/M) and ortho-xylene (βP/O) increased firstly, and then decreased. The two separation factors reached the highest point within the framework SiO2/Al2O3 molar ratio of 2.20-2.40. The separation factor of PX to ethylbenzene (βP/E) exhibited alinearly decreased trend with the increase of the framework SiO2/Al2O3 molar ratio. All of βP/M, βP/O and βP/E increased with the increase of Na+ exchange ratio, and maintained stable when Na+ exchange ratio was higher than 94.3%. As the water content in the BaX zeolite increased from 2.0% to 8.2%, βP/M, βP/O and βP/E increased firstly and then decreased, with the highest points in the water content range of 4.0-5.0%. The separation factor of PX to para-diethyl benzene (βPX/PDEB) in PX-PDEB binary mixture was also studied using static adsorption equilibrium experiment.The result showed that βPX/PDEBvaried with the changing of PX concentration in PX-PDEB mixture, and theX zeolite with high SiO2/Al2O3 molar ratio favored a small changing range of βPX/PDEB, the value of which was very close to 1.

MODIFICATION OF ACIDITY OF ZSM-5 ZEOLITE AND ITS ISOMERIZATION PROPERTIES

2016, 47(3):  5-9. 

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The evaluation of modified HZSM-5 was conducted by series of pulse reactions, using meta, ortho-xylene, toluene, ethylbenzene and meta- biisopropylbenzene. The modification of HZSM-5 was carried by liquid impregnation using citric acid, sulfide, aniline, diphenylamine, ammonium dihydrogen phosphate and silicone oil. The impacts of various modification methods on pore volume and surface area are weak, shown by BET. FTIR analysis showed that each modification processes are weakened acidity, the impact on L acid is greater than B acid. Five probe-reaction experiments indicated: the aniline, diphenylamine, sulfide and ammonium dihydrogen phosphate modification can enhance the shape-selectivity, and inhibit the xylene isomerization, the citric acid enhanced isomerization, disproportionation, reduced the selectivity, the silicone-modified passivated outer surface acidity, retained the activity in the channels.

EFFECT OF BR?NSTED ACID NUMBER ON MATRIX OF FCC CATALYST ON YIELD OF LIGHT OLEFINS

2016, 47(3):  10-15. 

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Through preparing modified alumina as the matrix component of FCC catalyst, the matrices with similar physical properties and different acidity in a practically meaningful range, the effects of the weak as well as strong Br?nsted acid number of the matrices were studied on the yield of the small olefins during the catalytic cracking process. Results showed that the increase in the weak Br?nsted acid number on the matrix surface gave a higher catalyst activity and a better selectivity in small olefins. By contrast, increasing strong Br?nsted acid number on the matrix surface resulted in a higher catalyst activity and a better selectivity to small olefins as well, but the non-selective hydrogen-transfer reaction was enhanced significantly at the same time.

STUDY ON GAS-SOLID FLOW CHARACTERISTICS AND CONTACT EFFICIENCY IN DUAL-LOOP CIRCULATING FLUIDIZED BED RISER

2016, 47(3):  16-24. 

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Effects of feeding structures with solids from single or double sides and ratio of solids circulation rates from both sides on the gas-solids flow characteristics were investigated in a cold model apparatus of a novel dual-loop circulating fluidized bed, and a new definition of gas-solids contact efficiency was also proposed to evaluate the reactor. Results showed that the solids feeding methods had very little impact on the axial and radial distribution of solids concentration when the solids came down from one or two sides, and the differences mainly lay in the pre-lifting and bottom reaction zones of the riser. When two strands of solids were feeding bilaterally into the riser bottom together, the solids contribution presented a better radial distribution than that of only single strand of solids feeding, and closer solids circulating rates of the two loops would contribute to better radial uniformity and axial symmetry of solids concentration profiles with higher gas-solid contact efficiency. And higher gas-solids contact efficiency could be obtained when decreasing superficial gas velocity or increasing solids circulation rates.

STUDY ON THERMAL CRACKING IN HYDROGEN OF RESIDUE WITH DIFFERENT ASPHALTENE CONTENT

2016, 47(3):  25-30. 

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Taking residue oil from TaHe as the object of the research, n-hexane as solvent to obtain asphaltene which was mixed with the residue oil to prepare the feedstock with different asphaltene content for autoclave hydrothermal conversion experiments. The characteristic of the reaction was analyzed by thermogravimetric analyzer and the structural differences of the unsaturated products were investigated by 1H-NMR and 13C-NMR. The results showed that asphaltene was the component that had a low thermal reaction activity. With the asphaltene content increasing, the yield of coke and gas presented linear increase, Sa* got the maximum value of 55.04% with 30% asphaltene content. In addition, various types of hydrogen and carbon content of cleavage products showed that with the asphaltene content increased, the break off of alkyl side chains and opening of naphthenic rings of the unsaturated components, which increased the content of aromatic hydrogen (HA) and hydrogen in the α-position to aromatic ring (Hα), the saturated carbon fraction f(CS) in Ar*, Re* and As* showed a significant decreasing trend, while the aromatic carbon fraction f(CA), co-bicyclic aromatic carbon fraction f(CAA) and tricyclic aromatic carbon fraction f(CAAA) showed a significant increase.

STUDIES ON PROPERTIES AND FLAME-RETARDED MECHANISM OF ECO-FRIENDLY SBS MODIFIED ASPHALT WITH FLAME-RETARDER

2016, 47(3):  31-35. 

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Research and development of a new environmental friendly flame-retarder asphalt were done for the reasons of the flame-retarder which is usually used now will smoke and produce large amounts of poison gas at high temperature, the influence of a compound environmental friendly flame-retarder on flame-retardancy property of SBS modified asphalt were studied by oxygen index test(LOI). The adding amount of compound environmental friendly flame-retarder is determined through the studies of the influence of a compound environmental friendly flame-retarder on flame-retardancy property, physical properties, kinematic viscosity at 135℃, rheological properties at high and low temperature of SBS modified asphalt.The environmental property of environmental friendly flame-retarder asphalt is studied. The rheological properties at high and low temperature and the flame-retarded mechanism of environmental friendly flame-retarded SBS modified asphalt were studied by dynamic shear rheometer,bending beam rheometer, DSC-TG and scanning electron microscope(SEM) test. The test results show that environmental friendly flame-retarder asphalt has good flame-retardancy, physical properties, storage stability and environmental property. The compound environmental friendly flame-retarder can improve the high temperature property of SBS modified asphalt, which can also slightly reduce the low temperature property of SBS modified asphalt. The compound environmental friendly flame-retarder also can increase heat decomposition temperature and initial burning temperature of SBS modified asphalt and the burning poison gas and smoke density was also reduced by it. The environmental friendly flame-retarder asphalt has good performance.

Cu/Ce MODIFIED CATYLYST ADDITIVE FOR REMOVAL OF SO2 FROM FCC FLUE GAS

2016, 47(3):  36-41. 

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Mg-rich Mg-Al spinel synthetized by Sol-Gel method and modified with CuO and CeO2 via co-gelling method was used to remove SO2 from FCC flue gas. Synthetic catalysts were evaluated on a fixed bed reactor and characterized with XRD, XPS, and Raman Spectra etc. Spinel with an mg-al ratio of 1:1 showed the highest SO2 removal activity. After modification of CuO and CeO2, it kept a desulfurization rate of 90.67% after 40 minutes. It was found that the generation of MgO-CuO solid solution was prevented in the presence of CeO2. So CuO had a better dispersion on the adsorbent surface and showed a better catalytic oxidation activity. At the same time, when CuO was added, oxygen defects were found in the lattice of CeO2 by Raman spectra. That improved the oxygen adsorption capacity of the catalyst. High catalytic oxidation activity and oxygen adsorption capacity of the catalyst enormously promote oxidation of SO2 to SO3, which is much easier to be adsorbed by spinel.

PREPARATION AND MODIFICATION OF Mo-BASED CATALYST AND ITS CATALYTIC OXIDATIVE DESULFURIZATION PERFORMANCE

2016, 47(3):  42-47. 

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SiO2 was synthesized through self-assembly method and the effect of different synthesis conditions on the pore structure and oxidative desulfurization were investigated including the concentration of silica source, the dosage oftemplate and the period of aging. The supported catalysts were synthesized by incipient impregnation method with the SiO2 as support, and then modified by the introduced citric acid (CA), Ce(NO3)3?6H2O and La(NO3)3?6H2O, respectively. A series of the modified catalysts were applied to catalytic oxidative desulphurization reaction to evaluate their performance with H2O2 as oxidantand then the reactionconditions on catalytic oxidative desulphurization of VGO were investigated. The results are that the best synthesis conditions of SiO2 are concentration of silica source of 0.68 mol/L, [CTAB]/[TEOS] of 0.22 and aging time of 2 h; The order of desulfurization performance is Ce-MoO3/SiO2＞CA-MoO3/SiO2＞MoO3/SiO2＞La-MoO3/SiO2; The desulfurization rate of VGO is 64.8% with Ce-MoO3/SiO2as catalystunder the optimal conditions (the temperature of 70 ℃,nO/nS of 8,the timeof 2 h, the dosage of catalyst of 15wt%).

IMPROVING LOW TEMPERATURE ACTIVITY OF Hβ ETHERIFICATION CATALYST BY PHOSPHORIC ACID TREATMENT

2016, 47(3):  48-53. 

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The low temperature etherification activity of molecular sieve is poor. Aimed at this shortcoming, using phosphoric acid solution acid treatment catalyst, the samples of before and after processing were characterized by XRD, XRF, BET, NH3-TPD and Py-IR. Results show that phosphoric acid treatment can maintaining catalyst crystal structure, increase the silica alumina mole ratio, wider pore size distribution, reaming effect obviously, acid amount and acid strength reduce moderately, but the number of strong acid site and the Br?nsted acid site increase significantly. The low temperature etherification activity of above catalysts was investigated in a micro fixed bed reactor. Results indicate that phosphoric acid treatment can significantly improve the low temperature etherification activity. The large pore size generated by acid treatment was beneficial to the diffusion of reactants and products and improved the catalytic efficiency. The increase of strong acid ratio and Br?nsted acid sites is the key to improve the low temperature etherification activity, while too high or too low of acid strength unfavorable to the etherification. The sample of 0.5PA has the best etherification activity, the conversion rate of isoamylene was 65.04%, and the selectivity of TAME was 97.55%.

STUDY OF HYDROCRACKING OF n-OCTADECANE OVER Pt/SAPO-11 CATALYST

2016, 47(3):  54-59. 

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The Pt/SAPO-11 catalyst was prepared by incipient-wetness impregnation method and characterized by X-ray diffraction (XRD), BET and NH3-TPD. The effects of Pt loading，reaction temperature，space velocity，reaction pressure and hydrogen-oil ratio on Pt/SAPO-11 were investigated. The result showed that the Pt/SAPO-11 exhibited better catalytic activity with a appropriate increasing of Pt loading，while raising temperature，decreasing space velocity and increasing pressure were favourable for hydrocracking，but higher hydrogen-oil ratio with easier isomerization resulted in a low oil yield. Under the conditions of 0.7% Pt loaded with SAPO-11，temperature of 380 ℃，pressure of 2.5 MPa，LHSV of 1 h-1，hydrogen-oil ratio of 1 000，oil yield had reached 52.2% and the selectivity of mono-branched isomers was 61.6%，along with middle/light distillates ratio of 1.57.

HYDRODESULFURIZATION AND OLEFIN AROMATIZATION OVER Co-Mo/ZSM-5 ZEOLITE TREATED BY MIXED ALKLI

2016, 47(3):  60-66. 

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ZSM-5 zeolites with different Si/Al ratios were treated by mixed alkali solution of Na2CO3 and TPAOH solution. The zeolites before and after alkali treatment were characterized by XRD, BET, SEM and NH3-TPD techniques. The results showed that the original zeolite frame structure was not destroyed after Na2CO3/TPAOH treatment, and the alkali treatment were beneficial to the increasing of specific surface area, external surface area, average pore size, and pore volume of mesoporous for HZ (80-4-0.2). With FCC gasoline as the raw material, the reaction of hydrogenation desulfurization and aromatic over CoMo/ZSM-5 catalyst prepared by ZSM-5 zeolites before and after alkali treatement were studied. At the certain reaction contion CoMo/HZ（80-4-0.2）showed the most desulfurization rate and the most yield of aromatization. The effect of process conditions on the reaction of hydrogenation desulfurization and aromatization of CoMo/HZSM-5(80-4-0.2) in a small fixed bed reactor was investigated. The results illustrated that when the reaction temperature was 400 ℃, the reaction pressure was 2.5 MPa, the reaction velocity was 1.5 h-1, the desulfurization rate was the higher, 94.2%., and the yield of aromatization was the larger, 30.82%.

OXIDATION-EXTRACTION DESULFURIZATION OF MODEL OIL OVER WO3-CONTAINING SBA-15/ZSM-5 COMPOSITE MOLECULAR SIEVE CATALYST

2016, 47(3):  67-71. 

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The SBA-15/ZSM-5 composite molecular sieves were prepared by post-synthesis method under hydrothermal condition. The WO3-SBA-15/ZSM-5 catalyst was prepared by loading H2WO4, on the carrier and characterized by means of XRD、SEM、and N2 adsorption-desorption. The results showed that the H2WO4 has achieved a uniform distribution on composite molecular sieves that exhibited the properties of both mesoporous SBA-15 and microporous ZSM-5. The effects of phase transfer catalyst, extraction agent, rotate speed on the desulfurization rate are investigated by the catalytic oxidative desulfurization method using model oil as raw materia1. The desulfurization rate is 85.48％ under the optimal conditions：20 mL of oi1, reaction temperature of 70 ℃, reaction time of 120 min, 0.08 g of tetrabutyl ammonium bromide, rotate speed of 300 r/min, dimethyl sulfoxide and water as complex extracting agent.

INFLUENCE OF Mg ADDITION ON PROPANE DEHYDROGENATION PROPERTIES OF Cr2O3/Al2O3 CATALYST

2016, 47(3):  72-76. 

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The influence of different Mg content of Cr2O3/Al2O3 catalysts for propane dehydrogenation reaction was investigated. The catalysts were characterized by N2 adsorption at low temperature，XRF，XRD，NH3-TPD，H2-TPR and SEM , to discuss the influence of different Mg content of Cr2O3/Al2O3 catalysts to catalyst physical structure, acidity, crystal type and valence state. Results showed that the major reason for MgO improves the reaction of propylene selectivity is that reducing the carrier surface acid amount, adjusting the valence distribution of Cr in the catalyst, and making the Cr better dispersion on the carrier. If the Cr2O3 content is 18% in the Cr2O3-MgO /Al2O3 catalyst, the appropriate addition of MgO is 1%—2% that catalyst had the best catalytic performance. Under the reaction condition, the propane average conversion of 33% was achieved with the corresponding propylene average selectivity of higher than 93% during reaction for 3 h.

PROCESSING MIXED FEED OF WAX OIL WITH FCC LCO IN WAX OIL HYDROTREATING UNIT

2016, 47(3):  77-81. 

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The wax oil hydrogenation unit hydrotreated 27.23%(w) catalytic diesel and 82.77%(w) wax oil. Under the operation condition: the reaction temperature was 363 ℃，inlet hydrogen partial pressure was 9.5 MPa, LHSV was 1.35 h-1, inlet ratio of hydrogen-oil was 493, the density of catalytic diesel was decreased from 0.983 6 g/cm3 to 0.918 5 g/cm3, the hydrogen content was increased from 8.34% to 10.92%, the nitrogen content was decreased from 633 μg/g to 67 μg/g, the single aromatic content was increased from 15.9% to 51.6%, the poly-nuclear aromatic content was decreased from 77.4% to 18.9%, the properties of the catalytic diesel had been improved significantly. The hydrotreated catalytic diesel mixed with the hydrotreated wax oil as the feedstock of catalytic cracking, the conversion rate of hydrotreated catalytic diesel was 48.15% and yield of gasoline was 40.41%.

REVAMP OF NATHPHA HYDROGENATION UNIT FOR FCC GASOLINE PREHYDROTREATING AND OPERATION ANALYSIS

Xue-Jun ZHANG

2016, 47(3):  82-85. 

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In order to decrease the content of mercaptans and diolefin in FCC gasoline, an existing 0.2 Mt/a naphtha hydrotreating unit was revamped to a 0.25 Mt/a FCC gasoline pre-hydrotreating unit adopting FCC gasoline pre-hydrotreating technology developed by Petrochemical Research Institute of PetroChina Company. The revamping include decreasing the diameter of naphtha hydrotreating reactor, increasing the stock strainer, coalescence dehydration device and so on .The performance test data show that the mercaptans content in FCC gasoline is reduced to 2.7 μg/g from 26.1 μg/g, the diolefin value is lowered to 0.20 gI/（100 g） from 0.64gI/（100 g） and no octane number loss is observed. Analysis on the process revamping, the performance test results and existing problems could be a reference for the revamping and construction of other similar units.

APPLICATION OF WASTE Ni-Mo HYDROGENATION CATALYST IN PREHYDROGENATION UNIT OF HYDROGEN MANUFACTURING PLANT

2016, 47(3):  86-89. 

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In this paper, we introduce the application of the waste nickel molybdenum catalyst to replace Fe-Mn catalyst in the hydrogenation unit of the hydrogen manufacturing plant. By analyzing the problems such as the possible occurrence of the carbonyl nickel reaction after using the waste catalyst, the decrease of the activity and the methanation reaction, the corresponding solutions were put forward. Through the industrial operation, the feasibility of the application of the waste nickel molybdenum catalyst used in the hydrogenation unit has been verified, 277 000 RMB of catalyst cost has been saved. This application not only extended the use cycle of nickel molybdenum catalyst, but also saved the cost of the new catalyst, which provides a new way for the solution of the catalyst source of the hydrogenation unit of the hydrogen manufacturing plant.

PROBLEMS IN COKING UNIT CAUSED BY RECYCLING DIRTY OIL AND SOLUTIONS

2016, 47(3):  90-93. 

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Coking device back to the refined oil and has large economic benefit and environmental value, but dirty oil qualitatively different smooth will affect the safety of equipment operation, even can also affect the quality of the product. Based on coking unit back to exist the problems in the process of refined oil, a series of solving measures are put forward. By adjusting the operation, to ensure the recycle process of product quality; Through reforming recycle process, implements the system of high water cut oil refining; By increasing the dirty oil reboiler and optimize the operation, can make a continuous recycle oil. The ultimate goal is to improve the economic benefit, protect the environment, promote the safe and smooth operation of the workshop.

PILOT TEST OF PRODUCING NAPHTHENIC TRANSFORMER OIL BY HIGH PRESSURE HYDROGENATION

2016, 47(3):  94-97. 

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Pilot tests of atmospheric distillate No.2 from Suizhong 36-1 crude were conducted to produce a special grade (I-30 ℃) transformer oil to meet GB 2536-2011 specifications by a process which simulates the Shell three high pressure hydroprocessing, and to study the effect of different process parameters on the performance of the transformer oil. The results indicate that a high quality transformer oil with excellent low temperature flow properties and antioxidant properties can be produced under the following conditions: Space velocity of 0.5/h, Gas/oil ratio of 1 000:1 and temperature of 340-360 ℃ for hydrotreating, Space velocity of 1.5/h, Gas/oil ratio of 1 000:1 and temperature of 350-360 ℃ for hydrodewaxing, Space velocity of 0.5/h, Gas/oil ratio of 600:1 and temperature of 200-210 ℃ for hydrofinishing. With addition of an additive package, the resulting transformer oil has all properties meeting GB 2536-2011 specifications, better than well-known brands of oil or its equivalent. The transformer oil can be made from atmospheric No.2 side cut of Suizhong 36-1 crude by high-pressure hydrogenation.

STUDY ON THE TRIBOLOGICAL PROPERTIES OF GEAR OIL WITH NANO-METAL/SERPENTINE POWDER

2016, 47(3):  98-102. 

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To improve the tribological properties of conventional gear oils, the affects of amounts and mass ratios of nano-Ni、nano-Ni/Cu composite powders and nano-metal/serpentine composite powders on tribological properties of gear oils had been studied by using four-ball tester, and studied its load characteristics. Experimental results indicated that the gear oils which had been added nano-Ni/Cu composite powders could achieve a better triboligical behavior than the one that had been added single powders, the friction coefficient and wear scar diameter decreased 37.8% and 30.2% , when the mass ratio of Ni and Cu was 3:1, and the total amount was 0.1%; The gear oils containing nano-metal/serpentine composite powders had better tribological properties in all aspects, and had a good load characteristics and self-repairing properties, the friction coefficient and wear scar diameter decreased 37.4% and 34.0% , when the mass ratio of Ni and Cu was 3:1, the mass ratio of metal and serpentine was 2:1, and the total amount was 0.2%. Wear scar morphology and EDS analysis showed that the nano-metal/serpentine composite powders added to the gear oil could fill a fill furrows and repair worn surface.

DETERMINATION OF DETERMINATION OF TOTAL CHLORINE CONTENT IN CRUDE OIL BY CHLORIDE ION SELECTIVE ELECTRODE METHOD

2016, 47(3):  103-108. 

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A detection method of inorganic chlorine and total chlorine content in crude oil was established. The contents of inorganic chlorine and total chlorine in crude oil were determined by the method of chloride ion selective electrode, with the method of high shear emulsification and oxygen bomb combustion. The results show that the method of chloride ion selective electrode can used for the detection of inorganic chlorine and total chlorine content in crude oil, with the linear equation of E=-17.11+54.37lgc, the correlation coefficient, R, of 0.9999， the linear range from 6.9×10-6 to 1 mol/L, and the lower limit of 6.9×10-6 mol/L. The conditions of inorganic chlorine extraction to water phase were as follows: 11000 r/min high shear dispersion 4 min , 1000 times extraction ratio of 100 mg/L NaOH solution and crude oil, extraction temperature of 80 ℃. The condition of oxygen bomb combustion of crude oil was combustion under 2 MPa oxygen pressure, and then absorption 30 min with 0.5 mol/L Na2CO3 solution. The recovery of inorganic chlorine and total chlorine was from 94% to 102%. The method was fast and accurate to the detection of inorganic chlorine, chlorine and total chlorine in the oil field.