Table of Content

12 February 2019, Volume 50 Issue 2

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KEY TECHNOLOGIES AND DEVELOPMENT OF CHINA’S VEHICLE GASOLINE QUALITY UPGRADING

2019, 50(2):  1-11. 

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The analysis and comparison of different gasoline production technology routes indicated that in the case of the compulsory implementation of ethanol gasoline in China, the first technical route for the production of qualified ethanol gasoline is the combination process of MIP-S Zorb or MIP-HDS. On the basis of this technology route, new technologies, like the FCC processes for producing gasoline with ultra low olefins, flexible adsorption desulphurization process, conversion of heavy fraction of gasoline to lights one and fine FCC as well are developed. By these processes combination, the olefin in gasoline can be reduced to less than 15% (φ) and RON increased by more than 1.5 points, the yields of isobutane and gasoline are significantly increased. It is expected to form a new technical route for vehicle gasoline production and provide reliable technical guarantee for the production of ethanol gasoline in China.

STUDY ON MIXED C4 HYDROGENATION PROCESS AND PYROLYSIS PERFORMANCE SIMULATION OF PRODUCT

2019, 50(2):  12-17. 

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The feasibility of hydrogenated mixed C4 with a total olefin content of about 38% as steam cracking material was studied. The selections of hydrogenation catalysts and process conditions were conducted. The composition of cracking product was calculated with the SPYRO software．The economic analysis of the process was examined．The data indicated that Ni containg catalyst NCG is the suitable catalyst, the best reaction conditions are: 60-90 ℃，1.5 MPa，the molar ratio of hydrogen to olefin of 2.0-4.0，the space velocity of fresh liquid feed of 2.0h-1 to 4.0 h-1．The simulation calculation results show that the hydrogenated mixture C4 used as cracking material can achieve good economic benefits of 25.40 million Yuan /a.

APPLICATION OF ON-LINE CATALYST REPLACEMENT TECHNOLOGY IN CCR UNIT

2019, 50(2):  18-22. 

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The third generation cyclemax technology of UOP was used in a 60kt/a CCR at Jingmen Refinery. In December 2017, the industrial application of on-line catalyst replacement technology was conducted on the device for the first time in China. It is certified that the technology of on-line catalyst change can create great economic benefits; after renewal of catalysts on line, the yields of H2 and C5+ liquid product increases and the H2 purity is higher. The timing of changing the catalyst is not subject to the restriction of scheduled maintenance time, and the device can complete the changing agent without stopping maintenance.

IMPROVING LIQUID YIELD OF DELAYED COKING BY ADDITIVES

2019, 50(2):  23-26. 

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The effect of three additives including metal compounds、aromatic components and radical generating agents on the distribution of delayed coking liquid products was investigated by the laboratory small coking evaluation device. It was found that the effect and mechanism of different additives on the yield of liquid products were different. Blending FCC slurry less than 10% has little effect on the product distribution of coking, and the liquid yield is increased slightly when blending 10% of the slurry. The coke yield decreases by 1.32 percentage points after adding tetralin, while the yield of liquid product increase 5.21 percentage points. However, due to its high cost, it is not suitable for popularization and application. Considering comprehensively, the metal compound additive has application prospect. The metal compound additive can increase the yield of liquid products by 1.2 percentage points.

STUDY ON LOW TEMPERATURE PYROLYSIS OF WASTE TIRE TO PRODUCE OIL

2019, 50(2):  27-30. 

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The low-temperature pyrolysis of the scrap tire was investigated by Fisher assay test and thermogravimetric test. Results showed that the main products were pyrolysis oil and carbon black with yield of 52.7% and 38.0%, respectively. The pyrolytic gas can meet the thermal energy demand of pyrolysis process without external fuel. The tire pyrolysis can be fully finished at 500℃, but takes longer time, about 180 min. Thus, it needs to improve pyrolysis process to enhance the equipment efficiency.

STUDY OF SPECIAL VISCOSITY INDEX IMPROVER FOR PHOSPHATE ESTER

2019, 50(2):  31-35. 

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Methacrylate is used as a raw material, a specific viscosity index improver polymethacrylate ( PMA) for phosphate ester was synthesized at a reaction temperature of 95 °C, an initiator dosage of 0.25 , a chain transfer agent dosage of 0.2 , and a reaction time of 4 h; The structure of the synthesized products was characterized by IR and NMR spectra. The application properties of the synthetic product were investigated by dissolving it in phosphate ester base oil. The results showed that the polymethacrylate product has a good solubility in phosphate ester, outstanding ability to improve the viscosity-temperature performance of the oil and excellent shear stability. It is an excellent specific viscosity index improver for phosphate esters.

DEVELOPMENT OF KEY COMPONENT OF HARD PAVEMENT BITUMEN

2019, 50(2):  36-39. 

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The vacuum residue suitable for preparation of key component of the hard pavement bitumen was screened. The key component from the selected VR was obtained through deep distillation, deep oxidation and solvent deasphalting. The performance of the key component was investigated. The test indicated that the prepared key component can improve the high temperature performance of the base bitumen and has a good universality. The hard pavement bitumen with good high temperature performance can be steady produced through blending this hard component at a suitable ratio, and the bitumen mixture produced from this hard pavement bitumen also has a good high temperature performance. Meantime, the pelletizing technology for key component was developed for flexible utilization and transportation of it. The suitable viscosity range for pelletizing is from 600 cP to 6000 cP. The hard road bitumen produced by key component is used in the real highway engineering. After more than 2 years of weather and traffic test, the bitumen pavement has no ruts or cracks and maintains excellent performance.

STUDY OF TRIBOLOGICAL PROPERTIES OF LEAF-SURFACE WAX AS LUBRICATING GREASE ADDITIVE

2019, 50(2):  40-44. 

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The main components of leaf-surface waxes are hydrocarbons, alcohols, acids and esters, among which hydrocarbons account for about 50%. The leaf-surface waxes of Populusnigra and Robiniapseudoacacia cv. Idaho were extracted and used as grease additives, and the resulting grease was compared with the pure alkanes added in the grease. A MTF-R4000 reciprocating friction and wear tester was used to investigate the effect of wax additives on the tribological properties of lithium complex grease. An optical microscope and an energy dispersive spectroscopy (EDS) were employed respectively to observe the surface morphology of the wear scars and analyze the elements on the surface of wear scars. The results showed that the leaf-surface wax can improve the friction reduction and anti-wear capacities of the lubricating grease more effectively than the pure alkanes. This attributed to the combined action of hydrocarbons, alcohols, esters and other components in the wax, forming an effective protective film through adsorption and chemical reaction, leading to the improved tribological properties.

EFFECT OF ORGANIC CORROSION INHIBITOR ON COPPER PLATE CORROSION BEHAVIOR IN EMULSION

2019, 50(2):  45-49. 

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The polarization curves and electrochemical impedance spectra were used to study the effects of organic soluble corrosion inhibitor, thiadiazoles, on copper plate corrosion in emulsion. The morphology of copper surface and the inhibition mechanism of corrosion inhibitor were investigated by SEM and XPS techniques. The results showed that the addition of soluble corrosion inhibitor in emulsion decreases sharply the current density of corroding copper plates and enhances its inhibition efficiency significantly. It is found that the emulsion with 1.5mol/L concentration of inhibitor shows the least corrosion. The formation of Cu (I)-inhibitor chelates film on the Cu surface due to the reaction of inhibitor with Cu is the reason of not further corroding the copper plate.

SIMULATION STUDY ON ADSORPTION AND DISSOCIATION OF HYDROGEN ON IRON, PLATINUM AND NIKEL METALS

Wang Chunlu Xie Zengzhong Zhao Yi Zhao Xiaoguang Wang Lixin Ren Qiang Ye Weizhen

2019, 50(2):  50-56. 

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The adsorption and dissociation mechanism of hydrogen on Fe (1 1 0), Pt (1 1 1) and Ni (1 1 1) surfaces were built based on the density functional theory (DFT) to study different adsorption conformations, dissociation energy barrier as well as electron density changes. DFT calculations indicated that the physical adsorption conformations of H2 on different metal surfaces are different, which may be related to the differences of cell structures and surface structures of different metals. Further calculations on the three metal surfaces showed that the three transition metals have similar catalytic activity on H2 dissociation, with the lowest energy barrier of hydrogen dissociation on Fe (1 1 0). The change of electron density distribution during the dissociation process indicated that H2 has the same electric charge transfer trend on the surface of three metals. It was speculated that H2 dissociation is achieved through the interaction between the d orbital of transition metal and the orbital σ* antibonding orbital of H2.

STUDY ON THERMAL OXIDATION MECHANISM OF JET FUEL

2019, 50(2):  57-62. 

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A self-built simulation oxidation device was used to investigate the oxidation process of the n-dodecane under the condition of heating and oxygen. The product compositions of the thermal oxidation process were analyzed from the molecular level using GC/MS. According to the consumption rate of reactants and the compositions of oxidation products, the decay characteristics of each component under the condition of heating oxidation were discussed. The results showed that the thermal oxidation of n-dodecane is a first order reaction. Thermal oxidation decay law is in accordance with the principle of free radical chain reaction. In the range of experimental temperature, the oxidation temperature does not change the oxidation path, but affects the oxidation rate, and the main oxidation products are consistent.

OMMERCIAL APPLICATION OF CMT-1HN CATALYST UNDER HIGH CONTENT IRON CONTAMINATION CONDITIONS

2019, 50(2):  63-67. 

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Processing heavy and bottom oil feedstocks affected the RFCC unit performance severely in SINOPEC Hainan Refining & Chemical Company due to high iron content deposited on the equilibrium catalyst (sometimes even higher than 10 000 μg/g), leading to lower conversion and target products yields and poor fluidization of the catalyst. To overcome the impact of the iron poisoning, CMT-1HN catalyst was developed by SINOPEC Research Institute of Petroleum Processing and commercial applied in above RFCC unit. The commercial application results showed that compared with the reference catalyst, CMT-1HN catalyst has a better bottom oil cracking ability and a higher gasoline yield, but lower dry gas and coke yields, indicating the better product selectivity and anti-metal deactivation ability of the catalyst. When the average contents of iron, sodium and calcium of feedstock increase to 35.35 μg/g, 4.73 μg/g and 8.11 μg/g, good performance is still maintained by using CMT-1HN catalyst.

DEVELOPMENT OF HYDROCRACKING CATALYST FOR HIGH YIELD CHEMICAL MATERIAL PRODUCTION

2019, 50(2):  68-72. 

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FC-46 is a new hydrocracking catalyst for maximally producing chemical materials. It is produced by UDRM technology using composite support of modified zeolite Y/macroporous alumina, W-Ni is used as a hydrogenation component. It was characterized by SEM and XPS techniques; the tetralin and dodecane were used to evaluate the performance of FC-46 catalyst. The results indicated that the conversion of tetralin increases by 0.7 percentage points, while dodecane conversion decreases by 2.1 percentage points using FC-46 compared with the reference catalyst. The industrial application of FC-46 catalyst showed that the activity of FC-46 catalyst is slightly higher than that of foreign catalyst: the heavy naphtha selectivity is 0.7-1.0 percentage points higher, the aromatic potential of heavy naphtha is 2.3-3.3 percentage points higher, the jet fuel smoke point is 2.5-3.7 mm higher, while UCO BMCI is 1.9-2.8 units lower than the reference catalyst.

STUDY ON PROPERTIES OF ONE-STEP PRESULFIDED Ni-Mo/Al2O3 CATALYST

2019, 50(2):  73-76. 

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One-step presulfided Ni-Mo/Al2O3 catalyst FS-1 was prepared by using a water-soluble complex sulfide as sulfurizing agent. The oxidation state Ni-Mo/Al2O3 catalyst FO-1 is used as the reference catalyst. The physical and chemical properties of the catalysts were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The performance of FS-1 and FO-1 on the hydrodesulfurization and hydrodenitrogenation of coking naphtha was investigated. The results showed that the performance of FS-1 is superior to FO-1. This attributes to the higher sulfidity of FS-1, the appropriate number of accumulation layers of MoS2, and the length of the wafer. It is easier to form the type II Ni-Mo-S active phase with high hydrogenation activity, so that it has higher intrinsic hydrogenation activity.

FAILURE ANALYSIS AND COUNTERMEASURE FOR CHECK VALVE

Zhang Dequan Wang Yanping Lu Junchen Jiang Chunming

2019, 50(2):  77-82. 

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In order to prevent the occurrence of check valve failure，aimed at control problems of check valves exposed by accidents，the failure mode and failure phenomenon of the check valve were summarized. The special analysis was made on the accidents caused in history by the check valve failure. The pertinent measures were suggested. Based on the failure mode of check valves，the deep-seated reasons such as design problems，quality problems and maintenance problems were analyzed. Comparing the design，maintenance and inspection standards of check valves，it is concluded that the main reasons for the poor reliability of the check valves during the process are the quality of manufacture，the selection of equipment，and the inspection and maintenance. Under the guidance of “the industrial valves-pressure testing （GB/T 13927-2008）”，the selection of the check valve must be on the basis of the leakage grade, which is of great guiding significance for improving the leakage grade and ensuring the quality of the purchase. At the same time，control measures for elimination of failure risk of check valves are suggested.

ANALYSIS OF FCC FLUE GAS WET DESULPHURIZATION AND DUST REMOVAL UNIT OPERATION

2019, 50(2):  83-88. 

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The operation state of the FCC flue gas purification unit, which is designed for the 1.2Mt/a FCC unit in the refinery of CNOOC Huizhou Petrochemical Limited Company, was introduced. The unit, adopting wet desulfurization and dust removal technologies, run smoothly for one year and reaches the design requirement, including pollutant emission, energy consumption and CEMS instrument system. However, two problems were found during the operation of the purification unit: the suspended solids concentration fluctuation for the waste water, and the blue smoke plume. The problems were solved by the process modification, three type additives application and the operation parameter optimization.

DEVELOPMENT OF NEW TYPE JET TRAY AND ITS INDUSTRIAL APPLICATION

Bo Dechen Liu Yuanzhi Chen Jianbing Gao Ming Zhang Ying

2019, 50(2):  89-94. 

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Aiming at the problems of high energy consumption and short running cycle of sour water stripping tower caused by the blockage of the tray, a new type of jet tray (SDMP) was developed by FRIPP, which possesses anti-blocking function. The structure of the tray was optimized using CFD simulation technology. Compared to the conventional F1 float valve tray，the results of hydraulic test proved that the pressure drop of SDMP decreases by 10%， the flux increases by 26%，the operating flexibility is almost the same. The industrial application results showed that the SDMP tray has a good anti-blocking performance. The sour water stripping tower with the new tray operates steady for more than 18 months; the steam unit consumption keeps stable and does not increase with the extension of running time. The average steam unit consumption is significantly lower than that of F1 tray.

DYNAMIC MODEL AND VERIFICATION ON DEEP DEWATERING AND DESALTING PROCESS FOR COAR TAR FEEDSTOCK

2019, 50(2):  95-100. 

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Medium and low temperature coal tar from a Shanxi factory is taken as raw material, the effects of washing-water injection temperature, injection rate, washing stag numbers, residence times and device structure, and water separation method on the deep dehydration and desalination of coal tar are investigated. The deep desalting results showed that at the water injection temperature of 60~80C, the number of washing stages of 2-4, water addition rate of 8-15% of the oil feed, the water separation time of 0.8-1.6 minutes, the better dewatering effect can be obtained in a coalescing separator. A kinetic model of dewatering and desalting of coal tar was established; the parameters of the model were fitted out with Matlab software and verified by real experiments. The results showed that the measured value and predicted value of the model are fit well, which indicates that this method is more suitable for the dewatering and desalting of coal tar raw materials.

DESIGN AND CONTROL OF LPG RECOVERY PROCESS FROM REFINERY FUEL GAS

2019, 50(2):  100-105. 

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Three recovery processes of LPG from fuel gas in a refinery are studied. On the basis of steady state simulation, the main parameters of each process were optimized, considering the minimum annual total cost as the objective function. The results showed that the process with dividing wall column can achieve 37.66% and 11.35% savings of annual total cost compared with the other two processes, indicating a greater economic advantage. Moreover, the dynamic characteristics of the dividing wall column process of LPG recovery from the refinery fuel gas were investigated. The proposed four-point temperature control structure can effectively handle the feed disturbance and has a good controllability. Therefore, the application of dividing wall column in the process has a very great potential.

DEVELOPMENT TREND OF ISOMERIZATION TECHNOLOGY FOR PARA- XYLENE PRODUCTION

2019, 50(2):  105-109. 

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The status of PX plant in China in recent years is summarized, and the industry development trend in the next few years is predicted. From the current situation and development of the isomerization process for increasing PX production, the ethylbenzene dealkylation process has the advantages of large processing capacity and high conversion rate of ethylbenzene, and is expected to occupy more market shares. An example of the transformation of the original converted type xylene isomerization device to the dealkylation process is analyzed. Although the implementation effect is not as good as the new device, the effective technical approach is to eliminate the bottleneck and optimize the operation process. In addition, the prospect of innovative research and exploration on the frontier of aromatic hydrocarbon production technology is also presented.