Table of Content

12 September 2017, Volume 48 Issue 9

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KEY TO DEVELOPMENT AND APPLICATION OF HYDROGEN ENERGY

2017, 48(9):  1-6. 

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Based on the analysis on energy efficiency, three waste discharges, and driving force for relevant industries of hydrogen manufactures from fossil and renewable energies and its utilization processes, it is recognized that hydrogen energy is the high efficiency way to utilize the primary energy sources and is the cleanest secondary energy. The development of the hydrogen energy will drive industrial innovation and industrial transformation. The risks in the development and applications of hydrogen energy can be controlled and the key is to develop a complete and systematic technical support. The technologies and equipments for developing and utilizing hydrogen energy in China are suggested.

STUDY ON XYLENE ISOMERIZATION MECHANISMS AND CATALYST IMPROVEMENT

2017, 48(9):  7-13. 

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By a series of probe molecule experiments, the aromatics reaction network was studied, the differences between the isomerization/disproportionation reaction path were compared，and the diffusion-reaction characteristics of aromatics with different sizes in ZSM-5 zeolite were analyzed. A model of xylene isomerization reaction was established. It is proves that only the aromatics with the size not larger than the benzene ring at least in one direction can diffuse into the ZSM-5 channel; the isomerization of lean PX feed occurs predominantly on the outside surface of the zeolite, the resulting PX diffuses into the channels, which then forms toluene through dealkylation. Based on this theory, a deethylation catalyst SKI-210 using the new molecular sieve with smaller size and larger surface was produced in industrial scale and applied in commercial units with good results.

DEVELOPMENT AND APPLICATION OF DEEP HDS CATALYSTS FOR AROMATICS-RICH GASOLINE

2017, 48(9):  14-19. 

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To meet the demand of producing national standard Ⅴ and Ⅵ clean gasoline, Ni-Mo/Al2O3 catalysts with high HDS activities were prepared by introducing a certain proportion of chelating agents into the impregnating solution. Using aromatics-rich gasoline with high sulfur as a raw material, the performance of the catalysts were evaluated in a 100ml fixed-bed reactor at conditions of 245 ℃, 2.0 MPa, space velocity of 1.5 h-1 and H2/oil volume ratio of 300. The results show that the sulfur content is reduced from 740 μg/g to 5.0 μg/g, desulfurization rate reaches 99.4% with RON loss less than 1.0, indicating that the catalyst is suitable for processing aromatics–rich gasoline.

INFLUENCE OF HCl ACID ON PROPERTIES AND HYDROCRACKING PERFORMANCE OF Al-SBA-15 MESOPOROUS MOLECULAR SIEVE

2017, 48(9):  20-26. 

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Using aluminium isopropoxide as aluminum source, TEOS as silicon source, a series of mesoporous molecular sieves of Al-SBA-15 was synthesized directly by one-step method in an acid medium with different amount of hydrochloric acid, followed by preparation of Ni-W hydrocracking catalysts. The molecular sieves and the catalysts were then analyzed by XRD，N2 adsorption and desorption，SEM，TEM and infrared spectrum. The results indicate that the Al-SBA-15 mesoporous molecular sieves have a highly ordered hexagonal structure with a strong acidity when 20 g hydrochloric acid was used in the acid medium. The heavy oil hydrocracking performance of the catalysts was evaluated and compared with the reference. The experimental results reveal that the selectivity and yield of middle distillate of the catalyst containing Al-SBA-15 mesoporous molecular sieves reaches 87.3% and 60.8%, respectively. The catalyst can be used for production of high quality diesel oil and jet fuel and the feed for reforming and ethylene cracking unit.

PREPARATION, CHARACTERIZATION OF ZSM-5 SIEVE WITH MESOSTRUCTURE AND ITS APPLICATION IN CATALYTIC CRACKING

2017, 48(9):  27-30. 

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A new type of mesostructured ZSM-5 sieve (ZSM-new) was prepared by alkali extraction method using CTAB as a framework protective agent and NaOH as alkali source, and tested to investigate its catalytic cracking performance. The new type of mesoporous ZSM-5 molecular sieve was increased significantly in terms of surface area and pore volume and crystallinity. Compared with the original ZSM-5 raw material and the mesostructured ZSM-5 sieve (ZSM-old) prepared by traditional alkali extraction method, the MAT activity of ZSM-new increases by 19 and 13 percentage points, the gasoline yield in the cracking products is up by 18.8 and 12.6 percentage points, and the RON of gasoline increases by 1.9 and 1.4, respectively.

PREPARATION AND PERFORMANCE OF AROMATIC SATURATION CATALYST FOR POOR QUALITY KEROSENE

2017, 48(9):  31-35. 

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The carrier was modified by phosphorus followed by preparation of aromatic saturation catalyst for kerosene by incipient impregnation of Ni-W solution. The catalysts were characterized by BET, XRD, H2-temperature programmed reduction, diffuse reflectance ultraviolet-visible spectra techniques. The aromatic saturation activities under different reaction temperatures and reaction pressures were investigated. The results show that the appropriate reaction pressure is 6.0 MPa, and adjusting reaction temperature is the main means for optimizing the process conditions. Compared with unmodified catalyst and reference catalyst, the phosphorus modified catalysts have a significant higher aromatic saturation activity.

LIQUEFACTION OF WOOD POWDER IN SUPERCRITICAL METHANOL

Jianbo Hu

2017, 48(9):  36-39. 

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The liquefaction of wood powder in supercritical methanol was investigated under different reaction conditions. The results indicate that the liquefaction, decomposition and gasification rate of wood powder were affected by the ratio of methanol to wood powder, reaction temperature and time, as well as type and amount of catalyst. At the best conditions: methanol to wood powder ratio of 4.5, 320℃, reaction time 1 h, and NaOH as catalyst, the liquefaction rate achieves 43.3%.

EFFECT OF INLET NOZZLE POSITION ON SOLID FLUX IN CIRCULATING FLUIDIZED BED REACTOR

2017, 48(9):  40-45. 

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Circulating fluidization, as an efficient and bubble-free contacting technology for gas and solid, is the research frontier of fluidization techniques. By a cold simulation apparatus with a riser of 10.6 m height and inner diameter of 100 mm, the effect of volume of pre-lifting gas as well as inlet jet gas on solid flux in circulating fluidized bed was studied. Especially, a comparative study of the solid flux with inlet nozzle at different positions as well as the difference of gas-solid flow behavior between region in the bottom and adjacent to nozzles was conducted. The gas distribution and flow structures in pre-lifting section in riser were described. The results show that pre-lifting gas and jet injection gas are the two important driving forces in pushing particles upward in riser. With the increase of jet inlet height, the effect of pre-lifting gas on solid flux becomes more obvious; the lower nozzle position shows the better performance in overall solid flux, solid holdup as well as gas-solid contact in nozzle region; Multiple gas countercurrent contact along with internal circulation flow as well as local vortex in bottom region of riser promote effectively the radial particle mixing and solid flux.

RELATIONSHIP BETWEEN PENETRATION GRADE AND HIGH TEMPERATURE PG GRADE OF CNOOC MODIFIED ASPHALT

2017, 48(9):  46-48. 

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Four kinds of commonly used CNOOC SBS modified asphalt were prepared from CNOOC 36-1 asphalt. The penetration at 25℃，ductility, softing point and PG high temperature parameters of the 4 samples were investigated by conventional penetration tests and DSR tests under multi-temperature conditions. Based on the test results, a relationship between penetration grade and performance high temperature grade PG was established. The correlation coefficient of the relational is >0.99. When PG level reaches 76 ℃, the 25 ℃ penetration result should not exceed 66.5; When PG level reaches 82 ℃, the 25 ℃ penetration should not exceed 63.0. The PG high temperature levels can well be estimated according to the penetration grade.

REGENERATION PROCESS OF MTP CATALYST

Jiang-Hong ZHAN

2017, 48(9):  49-53. 

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This paper discussed the effect of regeneration temperature and time, oxygen concentration and flow rate of regeneration gas on the performance of regenerated MTP catalyst. The changes of the regeneration conditions in the experimental ranges did not change the crystal structure of the catalyst. The optimized regeneration conditions are as follows: 500-600℃and 6-9h, oxygen concentration in regeneration gas ≥9.19% and regeneration gas flow rate of 1500-2100mL/(g.h).

PROBLEMS AT INITIAL STAGE OF DCC-PLUS UNIT, MEASURES ADJUSTMENT AND EFFECT

Zhao Changbin

2017, 48(9):  54-58. 

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A new 2200 kt/a unit adopting DCC-plus technology developed by Research Institute of Petroleum Processing SINOPEC, was set in CNOOC Ningbo Daxie Petrochemical Limited Company. There were some problems met at the initial stage of the unit: lower yields of ethylene and propylene than the design value due to the outsourcing e-cat for start-up and the feed qualities deviate from the design requirement. The ethylene and propylene yields are increased to 4.53w% and 19.52w%, respectively by means of optimizing operating parameters, ratio of feed composition and catalyst formula. These results meet the design requirements of DCC-plus unit and thus make the downstream ethylbenzene-styrene unit run at full capacity.

EFFECT OF PRESSURE ON PRODUCTION DISTRIBUTION AND ENERGY CONSUMPTION OF FCC UNITS

2017, 48(9):  59-62. 

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The effect of pressure on product distribution was investigated in a FCC pilot plant. The base-energy consumption of a FCC unit and the overall economic benefits without one-off investment was calculated based on the product distribution and the actual price system in 2015. It reveals that increasing reaction pressure causes the lower gasoline yield and base-energy consumption and lower octane number. As the pressure increases from 0.125 MPa to 0.247 MPa, the gasoline yield and the base-energy consumption decreases by 2.4 percent points and 245 MJ/t，respectively, and the overall economic benefit falls 147 RMB/t.

STUDY ON ADSORPTION ABILITY OF ORGANIC FRICTION MODIFIERS ON METAL IRON SURFACE

2017, 48(9):  63-68. 

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Quantum chemical density functional theory was used to study the interaction between the polar groups of friction modifiers (polyols, amide, carboxylic acid, amine, alcohol, and methyl ester) and metal iron. The structural characteristics of modifiers were studied to judge the active atoms of the modifiers and the possibility of chemisorption. The results show that the chemical action occurs between Fe and organic friction modifiers, such as propionic acid, propionate, propionate, propionate, propylamine. While physical action happens between propanol and Fe. The chemical adsorption energies were calculated between 5 kinds of polar groups and Fe. The intensity of adsorption is in the order: propionic acid glyceride ≈propylamine > propionic acid amide > propionic acid ≈methyl propanoate > propyl alcohol.

EFFECT OF DIFFERENT SATURATED HYDROCARBONS ON TRANSFORMER OIL PERFORMANCE

2017, 48(9):  69-74. 

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Effects of different saturated hydrocarbons on electrical performance, oxidation stability, solubility property, gassing tendency and thermophysical property of transformer oil were studied. The results show that the electrical performance, thermal performance, gas tendency, oxidation stability and the sensitivity to antioxidant of paraffin and naphthenic hydrocarbons were similar, while the naphthenic hydrocarbons have much better solubility properties than that of paraffin and is the ideal components for transformer oil.

ANALYSIS OF CATALYST CONVEYING FAULT IN SEMI-REGENERATIVE STANDPIPE OF FCCU AND RELATED MEASURES

2017, 48(9):  75-77. 

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The semi-regenerative standpipe is used for conveying catalyst between stacked two-stage regenerator in the FCC unit. Abnormal catalyst transportation occurred in standpipe during operation, which directly affected the unit operation and catalyst regeneration efficiency. Based on the analysis of the pressure balance of particle circulation loop, the cause is being the obstacle in inlet feed and outlet discharge, resulting in not enough driven force in the pipe for catalyst downward. By optimizing the fluxes of particle feed and discharge and controlling the loosen wind rate, the capacity of the catalyst transportation in standpipe can be effectively improved.

ANALYSIS AND EVALUATION OF HEAT INTEGRATION SCHEMES FOR DEEP CATALYTIC CRACKING AND GAS SEPARATION UNITS

2017, 48(9):  78-83. 

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DCC (Deep Catalytic Cracking) is a catalytic conversion process derived from the FCC (Fluid Catalytic Cracking) process, using heavy feedstocks for producing more propylene. The absorption-stabilization system of DCC unit and the gas separation unit followed requires more low-grade heat, compared with the conventional FCC unit. Hence, the heat integration schemes of DCC and gas separation unit have significant impacts on the low-grade waste heat recovery, steam balance and cooling duty. In this paper, exergy analyses with two heat integration schemes of DCC and gas separation units, including the direct heat integration scheme based on circulating hot water, and the scheme based on the heat pump process, are presented using process simulation software and ε-Q diagram. The analysis results show that the heat integration scheme based on the heat pump process can reduce 13.1% exergy loss of heat exchange process and the consumption of 1.0 MPa steam 20 t/h, but needs higher equipment investment costs. According to the study, the optimal matching of low-grade heat sources and sinks in DCC and gas separation units is a vital factor of increasing the energy efficiency.

OPTIMIZATION OF HYDROGEN SYSTEM BASED ON PLAN OPTIMIZATION MODEL

2017, 48(9):  84-88. 

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In this paper, the refinery hydrogen system was reallocated by means of a combination method of hydrogen pinch analysis technology and refinery operation planning optimization model to obtain optimization scheme of hydrogen system. Taking a domestic refinery as an example, the hydrogen reallocated scheme were calculated and analyzed by the pinch theory to meet the hydrogen purity required and to optimize the hydrogen network effectively by the combination method. It is shown by the results that this method can not only save the hydrogen 16.6% but also reduce the crude oil cost, while improves the ability of the refinery for processing lower quality freedstock.

IDENTIFICATION OF DIESEL TYPE BY PRINCIPAL COMPONENT ANALYSIS BASED ON DIAMONDOID FINGERPRINT PARAMETERS

2017, 48(9):  89-96. 

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Qualitative and quantitative analysis method of diamondoid hydrocarbon fingerprints were established based on gas chromatography/mass spectrometry (GC/MS). The contents of diamondoid hydrocarbon fingerprints in catalytic cracking diesels, hydrocracking diesels, and straight-run diesels were measured. The analysis results show that the concentration and distribution of diamondoid hydrocarbon fingerprints are different in the three types of diesels, but similar in the same type of diesels. Based on the distribution characteristics of diamondoid fingerprint compounds in different types of diesels, the fingerprint parameters were summarized, and 3 types of diesel were identified by principal component analysis (PCA). The results show that the positions are close together for diesels from the same process, and different types of diesels are discrete in the sample distribution map by PCA. Fast identification of diesel types can be realized by this method.

INFLUENCE FACTORS ON SULFUR DETERMINATION IN LIGHT OIL BY ULTRAVIOLET FLUORESCENCE SPETROMETRY

2017, 48(9):  97-102. 

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The total sulfur content in light oils was determined by ultraviolet fluorescence (UVF) spectrometry and the influence factors of impurities of oxygen, nitrogen, chlorine and metallic elements on the analysis accuracy were investigated by different types of instruments. Results show that oxygen has no influence on the accuracy of determination of sulfur content, indicating that the UVF method is especially suitable for determination of sulfur content of methanol gasoline, ethanol gasoline, biodiesel and biodiesel blends, and also suitable to the light oils with chlorine content less than 100μg/g. It is found that nitrogen has great influence on the accuracy of sulfur determination, and the interference extent relates to the instruments made by different factories. When the nitrogen in samples is more than 100μg/g, the influence of nitrogen must be taken into account. It is also found that no obvious effect is observed in the determination of sulfur content when the content of lead, manganese and iron is no more than 26 mg/L or silicon is less than 100mg/L.

DETERMINATION OF SILICON AND ALUMINUM IN PYROLYSIS TAR BY HIGH TEMPERATURE MELTING METHOD AND ATOMIC ABSORPTION SPECTROMETRY

2017, 48(9):  103-106. 

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Based on“Method for Determination of Aluminium and Silicon in Fuel Oil”, SH/T 0706-2001，an aqueous solution of sample was prepared from pyrolysis tar by high temperature melting method and then the content of aluminium and silicon in the solution was determined by nitrous oxide-acetylene flame atomic absorption spectrometry at spectral wavelengths of Si 251.6nm and Al 309.3nm, respectively. The interference and elimination of coexisting Si and Al elements on spectral lines are discussed. The results proves that addition of citric acid and lanthanum nitrate can eliminate the chemical interference with Al measurement from Si，and cesium chloride can remove the interference with Al determination from Al ionization. Precision and accuracy tests show that the relative standard deviation for each of the two elements is less than 5％，and the adding standard recovery is 97.6％to 102.4％.