Table of Content

12 September 2020, Volume 51 Issue 9

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STUDY ON RHEOLOGY PROPERTY OF LOW-VOLATILE GREASE

2020, 51(9):  1-6. 

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A low-volatile lubricating grease was prepared by using self-made multiple alkylcyclopentane (MACs) as base oil, self-made metal soap complex as thickener and various self-made additives. The performance of the prepared samples reached the level of the similar foreign product, and some of properties, such as saturated vapor pressure, were better. The rheological properties of lubricating grease, such as the change of modulus with shear strain, the change of apparent viscosity with temperature under constant shear, the change of viscosity with time under high shear and thixotropy, were studied by rheometer and the results were compared with that of foreign samples. The structural changes of thickener before and after shearing were characterized by SEM, and the shearing mechanism was analyzed. The results showed that the rheological properties of the developed MAC based low-volatile lubricating grease were better than that of the same kind of foreign product, which is conducive to improve the stability of rotating speed and service life.

EFFECT OF THICKENER ON LOW TEMPERATURE PERFORMACE OF GREASE

2020, 51(9):  7-10. 

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The low temperature performance of grease is becoming more important against the fast-growing of industry and defense industry. As one of the three major components of grease, thickener plays a vital role in the low temperature performance. The metal soap thickeners, Li-soap and Ca-soap, lithium complex soap thickener, calcium sulfonate soap thickener and non-soap thickener like bentonite and polyuria, were added to PAO4 and PAO10, respectively, to prepare greases with different thickener. The results indicated that the low temperature performance of the greases had great correlations with the type of thickener, the low temperature performance of single metal soap base grease is better than that of composite metal soap base grease. Being the same viscosity of base oil, the low temperature performance of metal soap grease was the best, followed by bentonite grease, lithium complex grease, polyurea grease and calcium sulfonate grease.

EFFECTS OF DETERGENT ADDITIVES ON PROPERTIES OF DIESEL ATOMIZED DROPLETS

2020, 51(9):  11-17. 

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The effect of the detergent additives on the properties of the diesel atomized droplets of the 0# diesel and the performance are investigated by the three-dimensional laser particles dynamic analyzer (PDA) and engine bench test. The PDA tests showed that with the increase of additive content, the droplets at the outlet of the nozzle tend to be distributed in the high-speed and small-size regions, and the proportion of the large droplets was decreased, and the proportion of small droplets was increased. With the increase of axial distance, the velocity of the atomized droplets decreased obviously whether or not the additive being added, while the droplets developed towards to the low speed and large particle size regions. Nevertheless, the distribution of the diesel atomized droplets containing additives was always less in the range of the large particle sizes, and the number, quality and velocity of the small droplets on the whole were better than that of the diesel without additive. The engine bench tests showed that the additive addition could effectively reduce the emissions of the pollutants (HC, CO, PM) and significantly reduce the air flow loss of engine nozzle.

STUDY ON SN 5W-30 GASOLINE ENGINE OIL FROM COAL-BASED BASE OIL

2020, 51(9):  18-22. 

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Compared with traditional mineral-based base oil and PAO6, coal-based base oil does not contain sulfur and aromatic hydrocarbons but has excellent low-temperature performance, and can be used as an ideal raw material for lubricating oil. Mixed coal-based base oil A and B with a ratio of 65:35 was used as composite base oil. Based on the study of the effect of the amount of additives on the pour point and kinematic viscosity of the composite base oil, the best composition was determined as follows: pour point depressant of 0.5%, composite agent of 9%, and thickener of 9%, respectively. The results showed that the main physical and chemical properties of the coal-based SN 5W-30 gasoline engine oil met the requirements of SN 5W-30 gasoline engine oil standard, and had good low temperature starting performance and mechanical wear resistance.

PREPARATION OF NEW SPECIAL WAX FOR PACKAGING

2020, 51(9):  23-27. 

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A special wax for packaging was prepared with excellent performances in heat-resistance, low temperature resistance, water proof, and ventilation for a corrugated box factory. Taking the mixture of No.58 fully refined wax and No.70 microcrystalline wax as base wax, the effects of addition of additives, assistant, and antioxidant on the drop melting point, viscosity, and appearance of the base wax were investigated. An optimum formula for the packaging wax preparation was determined when the dosage of synthetic wax, additive B, assistant 1, assistant 2, antioxidant was 9.8%，6.5%，1.5%，2.1%，0.1%, respectively. The special wax prepared at 160 ℃, 30 min and stirring speed of 200 r/mim had the advantages of high melting point, strong adhesion and good luster, which can meet the quality and appearance requirements of the corrugated box factory.

EFFECT OF DETERGENT ON DETERGENCY AND WEAR RESISTANCE OF BASE OIL CONTAINING ZDDP/MODTC COMPOUND

2020, 51(9):  28-33. 

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In order to investigate the effect of detergent on the performance of base oil containing zinc dialkyldithiophosphate(ZDDP) and molybdenum dithiocarbamate(MoDTC) as anti-wear and anti-friction agents, overbased synthetic calcium sulfonate(T106D)，overbased synthetic Magnesium sulfonate(T107), or alkylphenolate calcium sulfide (T115B) was added to the base oil containing composite ZDDP/MoDTC, respectively. The crankcase simulation test and four-ball machine wear resistance test were carried out. The high magnification scanning electron microscope(SEM) was used to characterize the surface morphology of steel ball after test. The results showed that the longer the crankcase simulation test time, the more obvious the difference in the base oil coking inhibition, and the addition of 3 detergents at the same time had the best detergency for the base oil with composite ZDDP/MoDTC. The base oil containing T107 had a lower coking tendency. The anti-wear test using the four-ball machine after the crankcase simulation test showed that the three detergents had little effect on the anti-wear performance of the base oil containing ZDDP/MoDTC compound. The main reason for the change in anti-wear performance was the decrease in the stability of MoDTC after high temperature. SEM results of the surface morphology of the steel ball showed that detergent would weaken the recovery effect of ZDDP/MoDTC compound base oil on the friction surface.

DEVELOPMENT AND INDUSTRIAL APPLICATION OF STRAIGHT-RUN DIESEL HYDROUPGRADING TO MAXIMIZE STEAM CRACKING FEEDSTOCK

2020, 51(9):  34-39. 

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In order to adjust the product structure, reduce the diesel/gasoline ratio, diversify steam cracking feedstock, and increase the economic benefits, the straight-run diesel hydroupgrading process to maximize the steam cracking feedstock was developed by SINOPEC Research Institute of Petroleum Processing (RIPP). The results showed that the diesel fraction produced by the developed hydroupgrading process with the proprietary catalyst developed by RIPP possessed high paraffin content and low aromatics content and was a good feedstock for steam cracking process. The industrial application demonstrated that the diesel fraction produced had a yield higher than 90% and contained more than 55% of paraffin, and could be stably produced for long-term. The developed technology provides a solid technical support for refineries to adjust the product structure and transform to chemical industry.

PRODUCTION OF No. 5 INDUSTRIAL WHITE OIL BY HYDROCRACKING

2020, 51(9):  40-44. 

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To further improve product structure, extend the range of high value-added products, and further reduce diesel output, the feasibility of producing No.5 industrial white oil in a 1.8 Mt / a hydrocracking unit was tested. The results of two technical trial productions showed that the industrial white oil can be produced from diesel feedstock through hydrocracking by adjusting process parameters and revamping the fractionation system of the hydrocracking unit. The pour points of the products were -15 ℃ and -16 ℃, the viscosities（40 ℃）were 4.299 mm2 / s and 4.415 mm2 / s, and the aromatic mass fractions were 2.95% and 2.59%, respectively, meeting the No.5 industrial white oil（Ⅰ）standard of NB / SH /T 0006-2017.

STUDY ON INDUSTRIAL APPLICATION OF MEMBRANE FILTRATION TECHNOLOGY FOR FCC SLURRY

2020, 51(9):  45-49. 

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In order to removal the solid catalysts in FCC slurry, SINOPEC Changling Company and Hunan Zhongtianyuan Environmental Engineering Co.Ltd. has joint developed a special high temperature resistant ceramic membrane and cross-flow filtration technology for FCC slurry filtration, and established a 100 kt/a FCC slurry membrane filtration unit. The calibration and long period operation demonstrated that after 14 months operation, the average yield of FCC slurry after membrane filtration was over 85%, and the ash mass fraction was less than 50 μg/g. The long period stable operation of the unit layed a good foundation for high value utilization of downstream products of FCC slurry.

APPLICATION OF SUPERCRITICAL FLUID EXTRACTION IN BRIGHT STOCK UPGRADING

2020, 51(9):  50-54. 

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Using propane as solvent，the quality upgrading process for bright stock was researched by supercritical extraction to explore the relations between extraction conditions and product qualities. The results showed that the yield could reach above 90% under the appropriate conditions and could be adjusted according to the demand. Compared with feed，the color and the oxidation stability of the extracted oil were significantly improved with a reduction of acid value and an increased viscosity index. The viscosity index of the extracted oil (yield 30%) was 105 with a viscosity of 17.23mm2/s. After the further process of complexation-adsorption refining, the oxidation stability, viscosity and pour point of the product can meet SINOPEC HVI Ia 120BS requirements. The new process can achieve the goal of subdivision for high boiling point BS that is difficult by the other conventional separation methods and has a greater practical value to downstream lubricating oil blending.

STUDY ON PRODUCTION OF LUBE BASE OIL FROM PARAFFIN-BASE VACUUM RESIDUE

2020, 51(9):  55-59. 

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High wax content paraffin-base vacuum residue was refined by solvent deasphalting process to obtain deasphalted oil, and then treated by hydrotreating-isodewaxing-hydrofinishing process, and vacuum distillation to obtain high value-added lube base oil series products. Research results showed that by controlling high pressure hydrogenation depth and adjusting the distillation cutting point, a series of base oils of 90BS, HVIH14, HVIH8, HVIH4, and HVIH2 could be produced. The total yield, based on deasphalted oil feedstocks, could reach around 75%, while total yield was about 34% based on vacuum residue. The differential utilization of vacuum residue can be realized.

ANALYSIS OF CATALYST FLOW PATTERNS IN CONVEYING INCLINED TUBE OF FCC UNIT

2020, 51(9):  60-64. 

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Inclined tube is the conveying pipe for catalyst circulation in FCC unit. Catalyst flowing smoothly in the pipe is one of the key points for the steady operation of the device. The fluidized states of the catalyst and gas in the inclined tube of a 3.3 Mt/a FCCU were analyzed by measuring the axial pressure profiles of the regenerator inclined tube and the catalyst apparent density in front of the slide valve. The result showed that the dense-phase flow was formed in the lower part of the pipe, resulting in a significantly increased friction pressure drop, which is the main cause for the reversal of axial pressure distribution. Inclined tube operation was divided into three parts according to the direction of gas flow: Part I was the negative pressure differential degassing region; Part II was the negative pressure differential gas holding region; Part III was the positive pressure differential gas holding region. The fluidized state of catalyst can be changed by adjusting aeration rate.

REASONS OF PRESSURE DROP RISE IN REACTION SYSTEM OF NAPHTHENE-BASE VGO HYDROCRACKING UNIT

2020, 51(9):  65-70. 

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Due to the rapid rise of system pressure drop，the naphthene-base VGO hydrocracking unit with a capacity of 2.1 Mt/a of CNOOC Ningbo Daxie Petrochemical Co. Ltd. had to be shut down. It was confirmed that the system pressure drop occurred mainly in the high pressure heat exchanger and partially in the refining reactor. The white dirt accumulated in the inlet distributor of high pressure heat exchanger and also deposited in the scaling basket and in the upper part of the guard catalyst of refining reactor, resulting in a rapid rise of system pressure drop. The white dirt is Fe2P4O12 formed by the reaction of iron element in the VGO feed and the phosphorus compound in the high temperature corrosion inhibitor in the upstream crude distillation unit. Countermeasures, such as controlling phosphorus content in hydrocracking feed below 0.5 μg/g，meanwhile adopting the phosphorus-free corrosion inhibitor or upgrading equipment materials in the upstream crude distillation unit, were proposed.

HYDROCRACKING OF TETRALIN OVER PHOSPHOROUS AND NICKEL MODIFIED MORDENITE ZEOLITE CATALYSTS

2020, 51(9):  71-78. 

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A series of P, Ni modified mordenite zeolite catalysts were prepared via impregnation, and systematically characterized by using XRD, FT-IR, NH3-TPD, 27Al NMR, 31P NMR, and nitrogen adsorption-desorption techniques. The results demonstrated that P efficiently weakened the acid strength through the coordination with the framework aluminum of zeolites, and simultaneously formed abundant L acid center through dealumination. Meanwhile, the introduction of Ni interacted with framework aluminum to form twisted tetra coordinated aluminum structure, but does not affect significantly the acid properties of zeolites. In the hydrocracking process of tetralin over those modified zeolites, Ni promoter greatly improved the hydrocracking activity of tetralin through H spillover between metal and acid site, while P modified zeolites exhibited better anti-coking ability and catalyst stability. The catalyst modified by the combination of phosphorus and nickel has appropriate hydrogenation function and optimized acid distribution, which improves the conversion rate of tetralin and the selectivity of single cyclic aromatic hydrocarbon, and also improves the operational stability of the catalyst.

SYNTHESIS OF ROD-LIKE γ-ALUMINA AND HYDRODEMETALLIZATION PROPERTY OF NiMo/γ-ALUMINA CATALYST

2020, 51(9):  79-85. 

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Rod-like γ-alumina support was successfully prepared from γ-alumina powder and ammonium bicarbonate by hydrothermal method, and NiMo/γ-alumina hydrodemetallization catalyst was prepared based on the prepared rod-like γ-alumina. The structure and properties of alumina support and the hydrodemetallization catalyst were characterized by XRD, SEM, N2 adsorption-desorption, TPR, Raman and in-situ CO adsorption techniques. The results showed that when the mass ratio of γ-Al2O3 powder to ammonium bicarbonate was 1:1.75 and the synthesis temperature was 140 ℃, the synthesized rod-like γ-alumina particle had a length of 0.5-3 microns and a diameter of 50—100 nm. The γ-Al2O3 support prepared from rod-like γ-alumina possessed the specific surface area of 276 m2/g and pore volume of 0.79 mL/g. Compared with the conventional alumina support, the NiMo/γ-alumina hydrodemetallization catalyst from rod-like γ-alumina was easy to be reduced, and there were many Ni-Mo-S active sites in the catalyst. Under the conditions of a LHSV of 1.0 h-1, a reaction temperature of 380 ℃, a V (H2)/V (oil) of 800, a hydrogen pressure of 15.7 MPa, the removal rate of metal impurities reached 59.8%.

INTELLIGENT OPTIMIZATION OF THREE-POINT STEAM INJECTION RATE IN DELAYED COKER FURNACE BASED ON AUTOMATIC REGULATION OF HEAT LOAD

2020, 51(9):  86-91. 

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A heat load automatic adjustment simulation method was applied for three-point steam injection in a delayed coker furnace. Based on the model，the influence of three-point steam injection rate on the coking degree and heat consumption was analyzed. The results showed that the rate of steam injection affected the heat consumption and the coking degree. Improving the steam injection rate would increase the heat consumption and decrease the coking degree at the same time. The steam injection rate of the first and the second point were sensitive to heat consumption and the coking degree, while the steam injection rate of the the third point had only weakly influence on the heat consumption and coking degree.In practice, the coking degree in the heating furnace can neither be too strong nor too weak, and the appropriate coking degree can ensure the furnace tube pipe not coking in the normal on-stream period and guarantee the economic consumption of methane gas,steam injection at the same time. Through intelligent distribution of heat load and steam injection, more reasonable operation schemes under different oil processing load of the device can be obtained.

RESEARCH ON MULTI-ELEMENTS ANALYSIS IN PETCOKE BY MICROWAVE ALKALI FUSION WITH ICP-AES AND MATRIX MATCHING METHOD

2020, 51(9):  92-97. 

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In order to accurately determine the element content in petcoke, the programmed temperature method in microwave muff furnace was used to ash the petcoke samples, followed by lithium tetraborate fusion treatment at 900 ℃ to prepare molten glass, and then dissolved in hydrochloric acid at low temperature to obtain the sample solutions to be tested. The element content of Al, Ca, Na, Fe, Mn, Ni, V and Si in the sample solutions were determined by the optimum characteristic spectral lines for each element using ICP-AES and matrix matching method. The standard recovery rate was between 95% and 105%, and the relative standard deviation (RSD, n = 6) of each element was less than 5%. The matrix matching method shows lower RSD and higher standard recovery rate than without matrix matching method.

ECONOMIC ANALYSIS OF OPTIMAL UTILIZATION OF LIGHT NAPHTHA

2020, 51(9):  98-103. 

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Based upon the principle of “producing the products according to feedstock features”, n-paraffins are separated from i-paraffin to realize the optimal utilization of light naphtha raw material. The light naphtha,which is rich in i-paraffin components with high octane number,is used as the gasoline blending component to increase the octane number and to improve the octane distribution of the gasoline pool. The light naphtha with more n-paraffin component can be used as steam cracking feedstock to increase the ethylene yield. In the case of insufficient octane number of the gasoline pool of the factory，the implementation of i/n hydrocarbons separation is very helpful to increase the octane number of the gasoline pool and the output of high-octane gasoline，and at the same time, increase the yield of ethylene products. Taking a refinery as an example, the implementation of the i/n-paraffin separation greatly improved the economic benefits. Based on the Brent crude oil price of $60 /bbl（1 bbl=159 L）in 2019, the revenue of gasoline and olefins products can be increased by RMB739.64 million per year. After deducting the increase of fuel power cost and auxiliary material cost of 76.74 million Yuan/a, the net income of the project is 662.9 million Yuan /a.

CORROSION FORM ANALYSIS OF ETHYLBENZENE PLANT

2020, 51(9):  104-109. 

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After two operation cycles and two major overhauls of ethylbenzene unit in a company，four corrosion forms were found：wet hydrogen sulfide corrosion，erosion corrosion by medium pressure steam condensate, weak acid corrosion, and low temperature dew point corrosion of air preheater of heating furnace. The causes for these corrosions were analyzed. It was concluded that the wet hydrogen sulfide corrosion, mainly existed in depropene system，was related to the content of hydrogen sulfide in catalytic dry gas; the erosion corrosion of medium pressure steam condensate mainly occurred at the elbow of pipeline，was related to material and process control; the weak acid corrosion in the cooling system on the top of non-aromatic tower，was related to device material and CO2 content of tower top gas; while the low temperature dew point corrosion in flue gas outlet of heat pipe pre-heater was related to process operation. Therefore, it is necessary to strengthen the monitoring of key parts, select material reasonably, and optimize operation conditions. After two operation cycles of the unit, the basic data has been accumulated for the parts prone to corrosion and thinning. Meanwhile, timely attention should be paid to the operation of similar units to ensure the stable long term operation.

ADVANCES IN APPLICATION OF MICROFLUIDIC CHIP TECHNOLOGY IN WATER ANALYSIS

2020, 51(9):  110-118. 

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Microfluidic chip technology applied in water analysis has attracted growing attention in recent years, due to its characteristics such as low consumption of sample and reagent, short analysis time, and great potential in multi-parameter detection, automation, integration and portability. Through the introduction of the development in component materials, fabrication methods, driving and control techniques, detection methods of microfluidic technology, the challenges on making microfluidic chip more portable, integrated and real-time are summarized. The applications of microfluidic chip in water detection of organics, nitrogen and phosphorus nutrients, metals, bacteria and microorganisms are discussed, and the prospect of its development is prospected.