Table of Content

12 March 2024, Volume 55 Issue 3

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DEVELOPMENT AND APPLICATION OF HYDROCRACKING CATALYST RHC-133

2024, 55(3):  1-8. 

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The new generation hydrocracking catalyst RHC-133 was developed by SINOPEC Research Institute of Petroleum Processing Co., Ltd. Compared with the third generation hydrocracking catalyst, the catalyst has higher selectivity of jet fuel and better quality of tail oil. The commercial application of RHC-133 catalyst in SINOPEC Qilu Company showed that the jet fuel yield of high pressure hydrocracking unit increased by 3.75 percentage points compared with the previous cycle, the diesel cetane index reached 58.9, and the pour point was -47 ℃. The tail oil BMCI decreased by 2.0 to 9.7 compared with the previous cycle. It was a high-quality feedstock for steam cracking to produce ethylene. The unit has achieved significant economic and social benefits. The application of RHC-133 catalyst in a refinery of PetroChina has also achieved similar good results.

REMOVAL OF TEMPLATE FROM Pd/FER AND ITS CATALYTIC PERFORMANCE FOR SKELETON ISOMERIZATION OF n-BUTENE

2024, 55(3):  9-20. 

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HFER-CHA was prepared and modified by palladium. The template was removed by calcination in flowing air at different temperatures. The effect of palladium modification on the removal of the template was investigated, and the catalytic performance for the skeletal isomerization of n-butene was studied, and the catalyst was characterized by XRF, XRD and NH₃-TPD, etc. The results showed that the calcination temperature affected the removal efficiency and properties of the zeolite template, and palladium modification significantly reduced the removal temperature of the template in the HFER. The template could be completely removed by calcining Pd/HFER-CHA in air at 350 ℃ for 4 h. The removal of the template increases the specific surface area and pore volume of zeolites. As the calcination temperature increases, the acidity of zeoilites increases, and the catalyst activity rises. The increase in Lewis-acid is the main reason for the side reactions such as polymerization and cracking of n-butene. After the Pd/HFER-350 was continuously operated for 720 h under conditions of 350 ℃, 0.1 MPa, and a mass space velocity of 2.0 h^-1 for n-butene,the average conversion rate of n-butene was greater than 40%, and the selectivity of isobutene was greater than 90%.

PREPARATION OF Cu-Mn-Si CATALYST AND ITS APPLICATION IN 2-BUTANOL DEHYDROGENATION

2024, 55(3):  21-26. 

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Cu-Mn-Si catalysts were prepared by coprecipitation method and sol-gel method respectively, and their performance in the reaction of 2-butanol dehydrogenation to methyl ethyl ketone was investigated. The catalysts prepared by the two methods were characterized by X-ray diffraction, programmed temperature reduction, nitrogen adsorption desorption and temperature programmed oxidation. The results showed that the crystal structures of Cu-Mn complex in the catalysts prepared by different methods were different. The crystal phase of CuMn₂O₄ in the catalyst prepared by coprecipitation and sol-gel methods belonged to JCPDS 71-1142 and JCPDS 34-1400, respectively. The catalyst prepared by sol-gel method had small crystal size, good dispersion and large specific surface area, so it had high activity. The addition of Mn did not improve the performance of the catalyst prepared by sol-gel method, but could decrease the reduction temperature of the catalyst prepared by coprecipitate method and improve the dispersion of copper components in the catalyst, thus improving the performance of the catalyst. Among the catalysts prepared by sol-gel method, Cu-Si catalyst had the highest conversion rate of 2-butanol, selectivity and yield of methyl ethyl ketone, reaching 99.26%, 99.19% and 98.45%, respectively. When n (Cu)∶n (Mn)∶n (Si) = 0.8∶0.2∶1, the catalysts prepared by coprecipitation method had the highest conversion rate of 2-butanol, reaching 94.92%, the selectivity of methyl ethyl ketone was 98.53%, and the yield of methyl ethyl ketone was 93.52%.

THE FIRST APPLICATION OF PHD-112/PHU-301 GRADED CATALYST IN THE PRODUCTION OF CHINA Ⅵ LOW POUR POINT DIESEL

2024, 55(3):  27-31. 

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In order to flexibly adjust the ratio of diesel to gasoline and produce low pour point diesel while taking into account the high production of naphtha in winter, a new generation hydrofining catalyst PHD-112 and a hydrocracking catalyst PHU-301, developed by PetroChina Petrochemical Research Institute, were used to produce low pour point diesel in accordance with the standard of China Ⅵ in Refining and Chemical Complex of Yumen Oilfield，PetroChina. After stable operation of the unit for 3 months, calibration work was carried out. The results showed that after the mixture of FCC diesel, coker gasoline, and straight-run diesel was treated with graded PHD-112/PHU-301 catalysts, the sulfur content, nitrogen content and polycyclic aromatic hydrocarbon content of feed oil decreased from 4 260 μg/g to 3.6 μg/g, from 96 μg/g to 0.32 μg/g, and from 18.9% to 6.2% respectively, the hexadecane index increased by 1.6, the condensation point decreased to －28 ℃, and the cold filter point decreased to －20 ℃. At the same time, naphtha yield increased by about 10 percentage points (relative to feed amount), which showed that PHD-112/PHU-301 catalyst had good performance in desulfurization, denitrification, pour point depression and naphtha production. It could meet the production of low pour point diesel with China Ⅵ through diesel hydrotreating unit.

OPERATION ANALYSIS AND R&D SUGGUESTION FOR FIXED BED RESIDUE HYDROTREATING PROCESS WITH PRE-UPFLOW REACTOR

2024, 55(3):  32-37. 

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Because of the high price of crude oil, it is necessary to utilize crude oil resources efficiently, and residue hydrotreating technology is a better choice. The residue hydrotreating technology with the combination of micro expansion upflow reactor and fixed bed reactor has been successfully developed and applied several times. Two sets of pre-upflow reactor residue hydrogenation units(A and C) and two sets of fixed bed residue hydrogenation units(B and D) were selected for comparative analysis. The result showed that the residue hydrogenation process in the upflow reactor could also process different types of residue. The residue feedstock with high nitrogen content was treated by unit A, and the desulphurization rate, nitrogen removal rate, metal removal rate and carbon residue reduction rate in RUN-14 period were 82.46%, 31.51%, 73.69% and 54.85%, respectively. High sulfur content residue was treated by unit C, and the desulphurization rate, nitrogen removal rate, metal removal rate and carbon residue reduction rate in RUN-5 period were 85.23%, 38.71%, 72.83% and 54.49%, respectively. The performance of graded catalysts can meet specifications of two units. As with fixed-bed residue hydrogenation unit, the first catalyst layer of the upflow reactor also had a large radial temperature difference, and the pressure drop of the first reactor also increased, it was mainly related to the mal-distribution of fluids and expansion degree in the catalyst bed. It is suggested that collaborative research and development of upflow reactor internals, catalysts, and key process parameters should be carried out.

RENOVATION SCHEME OF DIRTY OIL RECOVERY TECHNOLOGY IN DELAYED COKING COMBINED UNIT

2024, 55(3):  38-42. 

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A large amount of dirty oil is produced in the preheating and cooling processes of coke drum, among which the light dirty oil during the preheating and cooling stages cannot be directly recycled due to its high water content. In traditional processes, this part of the dirty oil is mainly treated through long-term sedimentation and dehydration in the dirty oil tank before being recycled, resulting in the problems of prolonged treatment cycles, heat loss, and environmental pollution. In order to realize the direct recovery of the dirty oil, CNOOC Ningbo Daxie (Zhoushan) Petrochemical Co., Ltd. modified the venting system and the recovery process of the 2.4 Mt/a delayed coking unit, adding hot VGO feed, injection agent, waste heat recovery and direct refining process of light and heavy dirty oil. The goal that dirty oil could be directly refined without settling into dirty oil tank was realized, the process of dirty oil recovery was shortened, the energy consumption of the unit was decreased, and the environmental pollution was reduced. After modification, the amount of dirty oil thrown outside the unit decreased from 67 t/d to 0, which has achieved good energy-saving and emission reduction effects.

PROCESS ACCOUNTING AND TECHNICAL ANALYSIS OF DCC UNIT IN LONG-TERM OPERATION

2024, 55(3):  43-49. 

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During the second operation period of the deep catalytic cracking-plus(DCC-plus) unit of Dongfang Petrochemical Co., Ltd., the properties of raw materials of the unit changed frequently and the operating conditions was adjusted greatly. Based on the properties of raw materials and catalysts, through regular process accounting and technical analysis, the preheating temperature of raw materials, steam injection, reaction severity and line speed of key parts were regulated, the operation parameters of the slurry system were stabilized, and the equipment management was optimized, etc., which ensure that no unplanned shutdowns occured during the second operation period of the unit. The maintenance period of DCC-plus unit was successfully extended from 3 years to 4 years.

CAUSE ANALYSIS OF COKING IN THE REACTION SYSTEM OF CATALYTIC CRACKING UNIT AND CUONTERMEASURES

2024, 55(3):  50-54. 

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According to the coking mechanism and the actual operation of a 2.2 Mt/a catalytic cracking unit in a petrochemical enterprise, it is considered that the atomization effect of feedstock is not good and the contact of oil agent is not uniform, the existence of non-vaporized oil is the main cause of coking in riser and affects the coking in follow-up system. When the temperature is lower than the dew point temperature of the heavy component, the droplets will condense, the heavy oil droplets and the catalyst will stick to the wall or inner component in the stationary region and the region where the oil and gas flow changes greatly, and then the dehydrogenation and condensation reaction will gradually solidify and accumulate to form large coke blocks. The process optimization measures of strict control of raw material quality, control of reaction depth, reduction of slurry refining amount, improvement of catalyst performance and increase of reaction steam injection amount were adopted, and some technical improvement measures were taken, such as optimizing degassing tank, setting up middle pressure anticoking steam ring, and optimizing cyclone separator, etc. The results showed that the coking of the reaction system was effectively alleviated, and the safe long-term operation of the device was ensured.

STUDY ON SEPARATED POLYCYCLIC AROMATIC HYDROCARBONS FOR THINNING AND VISCOSITY REDUCTION OF ULTRA-HEAVY OIL

2024, 55(3):  55-60. 

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Aiming at the problems of large excess of FCC diesel fuel in refineries and high aromatic content in FCC diesel fuel, and the present situation of heavy oil production by blending dilute and viscosity reduction with high blending ratio and scarce resources of diluted oil, extraction and separation of polycyclic aromatic hydrocarbons from FCC diesel fuel were used for the study of ultra-heavy oil blending dilute and viscosity reduction. Orthogonal experiments were carried out for the extraction of polycyclic aromatic hydrocarbons. Under the selected optimal operating conditions (agent-oil volume ratio 1.4, extraction temperature 45 ℃, extraction time 5 min and phase separation time 5.5 min), the yield of polycyclic aromatic hydrocarbons was 29.87%, and the content of aromatic hydrocarbons was as high as 99.07%. At the same dilution ratio of 0.10, the viscosity reduction rates of polycyclic aromatic hydrocarbons and Tahe thin oil were 68.58% and 94.20%, respectively. The fitting results showed that when the polycyclic aromatic hydrocarbon consumption was only 16.32% of Tahe oilfield thin oil, the heavy oil blending with thin oil could meet the viscosity reduction requirements of Tahe oilfield. Taking the heavy oil self-flowing wells in Tahe oilfield as an example, compared with thin oil, when the water content of heavy oil was 0, 30% and 50%, the daily oil production growth rate of single well with polycyclic aromatic hydrocarbons reached 115.90%, 84.57% and 62.20%, respectively.

INCREASING PRODUCTION MEASURES AND PRACTICE OF PENTANE FOAMING AGENT BASED ON ASPEN SOFTWARE

2024, 55(3):  61-66. 

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In refining and chemical enterprises, pentane foaming agents can be produced by light naphtha components extracted from pre-hydrogenation units. After the implementation of the national standard GB/T 22053—2020, the quality requirements for foaming agents are stricter. By constructing an ASPEN PLUS model for the stripper, fractionating column, and depentanizer of the pre-hydrogenation unit, the control parameters of the pentane foaming agent production process were analyzed and calculated，and a production adjustment plan was developed. The results of industrial tests showed that the proportion of pentane foaming agent was closely related to the temperature of the sensitive plate at depentanizer overhead, and the temperature change at the top of the column should be controlled at ±0.3 ℃ to ensure that the composition range of the foaming agent was ± 2%. At the same time, the effects of increasing production of pentane foaming agent were analyzed from aspects of the stripping column, product grade and type of crude oil processed to improve the economic benefits of the enterprise.

STUDY ON KINETICS OF HYDROGEN PRODUCTION FROM DISTRIBUTED METHANOL REFORMING AND REACTOR INTENSIFICATION

2024, 55(3):  67-74. 

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A dual-rate kinetic model of power function type was obtained based on the SR-DE mechanism and the intrinsic kinetic data. It was revealed that the methanol cracking reaction was kinetic-control, while the methanol steam reforming reaction was diffusion-control within the process conditions studied according to the analysis of internal diffusion influences. Optimizing the pellet size could enhance the mass transfer within the pellets, thereby effectively improve the apparent activity of the catalyst. Multi-physical field simulations of a single-tube methanol reforming reactor were carried out by using COMSOL Multiphysics 6.1. To discuss the matching of process conditions, catalysts and reactor structure, the performances of the methanol-reforming reactor with different catalyst activities were simulated under the same structure and process conditions. Optimizing the reactor tube structure could enhance the heat transfer process, improve heating efficiency, reduce bed temperature difference, and significantly improve catalyst utilization efficiency and device energy efficiency.

BINDING ENERGY AND KINETIC ANALYSIS OF CARBON DIOXIDE ABSORPTION BY POTASSIUM GLYCINE SOLUTION

2024, 55(3):  75-81. 

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In response to the lack of quantitative kinetic research on the CO₂ absorption process, which restricts the development of new absorbent, the binding energy of potassium glycine (PG) to CO₂ was simulated and compared with the ethanolamine (MEA)- CO₂ system. Furthermore, the kinetic laws of PG solution absorbing CO₂ under different conditions were experimentally studied. The results showed that the binding energy of the PG-CO₂ bimolecular system was obviously higher than that of MEA-CO₂, but the binding energy of PG-CO₂ was similar to that of MEA-CO₂ in the aqueous solution model. The interaction between adsorbent and water may affect its capacity to absorb CO₂. The higher the concentration of PG solution, the lower the CO₂ absorption load. The CO₂ absorption load of 1 mol/L PG solution was 0.584 mol/mol, which was close to that of MEA solution at the same concentration. At 40 ℃, the CO₂ absorption of PG solution was the highest. With the increase of CO₂ flow rate, the reaction rate increased and the CO₂ absorption rate decreased. The activation energy of the reaction between PG and CO₂ was 28 kJ/mol, which was lower than that of MEA. PG and MEA have similar CO₂ absorption capability, which provides the kinetic basic data for the development of new non-corrosive absorbent.

THERMODYNAMIC ANALYSIS AND KINETIC SIMULATING ON SYNTHESIS OF ETHYLENE CARBONATE

2024, 55(3):  82-88. 

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Ethylene carbonate (EC), produced from ethylene oxide (EO) and carbon dioxide (CO₂) via esterification addition reaction, can provide an excellent solvent for vehicle power batteries as a green new energy. The production route is a route in line with "green chemistry". More importantly, it can open up a green route of carbon capture, utilization and storage. In order to study the possibility and degree of the reaction, the thermodynamic analysis of the reaction process was carried out by the basic thermodynamic formula, and the macro-kinetic model of the main reaction was established to guide the design of industrial reactor. The results showed that the main reaction and other side reactions were all strong exothermic reactions except that the side reaction of EC hydrolysis was endothermic reaction, and all side reactions could proceed spontaneously, while the main reaction could not proceed spontaneously when the temperature was higher than 100 ℃. Then a macroscopic kinetic model including main reaction and side reactions was established to guide the design of industrial reactors. In this model, the kinetic parameters of all reactions were obtained by the regression of experimental data and verified by the industrial data. The product concentration at the outlet of the two CSTR in series was predicted by using the established kinetic model, and the EC molar fraction was 98.91%. The error between the calculated value of the kinetic model and the industrial test value was less than 0.12%.

REAL-TIME STATE EVALUATION OF PETROCHEMICAL PLANTS BASED ON IMPROVED TOPSIS

2024, 55(3):  89-96. 

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In response to insufficient training samples under multiple operating conditions of petrochemical plants, which makes it difficult to meet the data requirements of traditional state evaluation methods, a state evaluation method based on improved TOPSIS (the technique for order preference by similarity to ideal solution, TOPSIS) was proposed to avoid dependence on historical data. First, the positive and negative ideal solutions were determined by expert experience and process index control limits of process cards in the improved TOPSIS. Then, the two types of indicators, such as fixed value index and fixed interval index, were established according to the characteristics of operating parameters. Moreover, the evaluation standards were determined. The proposed method was employed to deal with the abnormal data of a reaction and regeneration system in a fluid catalytic cracking unit from a refining company. The results showed that the proposed method could quantify the real-time operating status of petrochemical plants.

MODE-FREE ADAPTIVE CONTROL WITH REAL-TIME PARAMETER TUNING AND ITS APPLICATION IN GAS FRACTIONATION UN

2024, 55(3):  97-106. 

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In the existing model free adaptive control (MFAC) algorithms, the four model parameters λ, ρ, η, μ are kept constant during the control process, which leads to the problems of small influence of pseudo-partial derivatives on the control process and weak adaptive energy of the algorithm. Using the radial basis function (RBF) neural network, based on control input and pseudo partial derivatives, and taking the difference between the expected output and the real-time output as the training error, the four parameters can be adjusted in real time, which improves the existing compact format dynamic linearization MFAC method for discrete time nonlinear systems. Furthermore, a new BRF-MFAC algorithm was proposed, and its superiority of tracking performance was verified in the control of a nonlinear system. Compared with MFAC, the operation adjustment time of RBF-MFAC system for propylene concentration could reduce by 42.4% in the propylene separation column of a 0.3 Mt/a gas fractionation unit. The operational adjustment time of propylene product concentration and production in MIMO system could reduce by 78.0%.

SIMULATION OF n-PENTANE AND 1-PENTENE EXTRACTIVE DISTILLATION PROCESS

2024, 55(3):  107-112. 

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With the continuous development of ethylene industry, the separation and utilization of by-product cracking C₅ component to improve the added value of C₅ has become the trend of development in the future. Taking n-pentane/1-pentene system as an example, the extractive distillation process of n-pentane/1-pentene system was simulated using three common extractants, such as acetonitrile, N-methylpyrrolidone and 2-butanone, the simulated energy consumption of different extractants was compared under the conditions of specified purity (≥ 95%) and recovery (≥ 90%), the corresponding mathematical model was established, and the extraction process was analyzed and optimized. The effects of other factors such as the number of trays, reflux ratio, feed position and extractant dosage were further optimized. The results showed that N-methylpyrrolidone was more reasonable as extractant. The optimized operation conditions were as follows: the number of theoretical trays was 65, the feeding positions of raw materials and extractants were at the 45^th and 5^th trays respectively, the reflux ratio was 3.7, and the extractant flow rate was 1 030 kg/h. Under these conditions, the purity of n-pentane was over 95%, and the recovery was over 91%.

DETERMINATION OF C₇ ETHERS IN GASOLINE BY GAS CHROMATOGRAPHY WITH OXYGEN SELECTIVE DETECTOR

2024, 55(3):  113-117. 

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Etherification of gasoline is the main way to produce gasoline with low olefin content and high octane number. With the upgrading of oil quality, the content of oxygen compounds in gasoline is strictly limited. At present, the main focus of ether compounds in gasoline are methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (TAME), diisopropyl ether (DIPE) and other C₅-C₆ ethers, but there are few reports on C₇ ethers. In this paper, a method for detecting C₇ ethers in gasoline was established by gas chromatography-oxygen selective flame ionization detector (GC-OFID). Compared with direct mass spectrometry and the NB/SH/T 0663-2014 standard method, hydrocarbons do not interfere with the determination of C₇ ethers by GC-OFID. The linear range (w) of the method was 1%-5%, the coefficient of determination r² was 0.999 9, and the detection limit (w) was 0.010% . Four structures of C₇ ethers were determined by GC-MS. The recoveries of C₇ ethers in automotive gasoline were 95.1%-103.5%, and the relative standard deviations (RSD, n=4) were 0.2%-0.6%. The method has good repeatability and high accuracy. The established method can be used for the determination of alcohols and ethers in gasoline samples from different process sources, which lays a foundation for the quality assurance of automotive gasoline.

SCREENING, IDENTIFICATION AND DEGRADATION CHARACTERISTICS OF HIGH CONCENTRATION DIESEL DEGRADING BACTERIA

2024, 55(3):  118-123. 

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A highly efficient diesel degrading strain was isolated from petroleum hydrocarbon contaminated soil at the decommission-site of a petrochemical plant. The strain was identified as Bordetella by morphological observation and 16S rRNA gene sequence analysis, named Bordetella sp.T3. T3 is suitable to grow in medium temperature and weak alkaline environment. It could degrade diesel oil under the conditions of a diesel volume fraction of 1%,  an inoculation amount (φ) of 2%,a temperature of 30 ℃ and a pH of 8.0, and the degradation rate of diesel could reach 89.79% on the 7th day. T3 could tolerate high content of 10% diesel, and the degradation rate of diesel was 38.57% under optimal culture condition for 7 days. The results of degradation spectrogram analysis showed that T3 could effectively degrade the main components (C₁₀-C₂₂) of diesel, and had a good application potential for remediation of petroleum hydrocarbon pollutants.

LOW-COST PREPARATION OF SUPER-HYDROPHILIC ALKALI-ACTIVATED SLAG/COPPER MESH COMPOSITE MEMBRANE AND ITS OIL-WATER SEPARATION PERFORMANCE

2024, 55(3):  124-131. 

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Super-hydrophilic membranes have been widely concerned in oil-water separation, but they are still limited by high cost, complex preparation process and weak stability. In this study, a super-hydrophilic alkali-excited slag/copper mesh composite membrane was prepared by a simple "coating-curing" process using low cost, green slag solid waste as raw material, and the effects of the preparation process conditions on the membrane performance were investigated. The results showed that the water flux of the optimal membrane under gravity conditions was 126.97 L/(m²·h), and the separation efficiency of cetane and other emulsions was more than 99% , and the efficiency of cetane emulsion was maintained above 99.30% after 10 consecutive treatments. The super hydrophilicity and hydrophobicity make the membranes have good self-cleaning, and can maintain high stability and separation efficiency even under harsh conditions.

REUSE OF RECLAIMED WASTEWATER FROM DESALTED WATER PROMOTING ANAEROBIC SLUDGE GRANULATION OF PTA WASTEWATER

2024, 55(3):  132-137. 

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Fujian Fuhaichuang Petrochemical Co., Ltd. consists of three main factories, including an aromatic plant for production of PX, a PTA production plant and a self-distributed thermal power plant for heating and electricity generation. A large amount of desalted water is required in the production of these three plants, thus a considerable amount of regenerated wastewater with high concentration of inorganic salts is produced. The regenerated wastewater containing high concentration of inorganic salts for desalination was diverted to PTA wastewater treatment unit, uniformly diluted and added to PTA wastewater UASB (up-flow anaerobic sludge bed) anaerobic reactor as an anaerobic microbe micronutrient. After four months of operation, the granular sludge accounted for more than 60% of the total anaerobic sludge, and the COD removal rate of the anaerobic reactor increased by more than 5 percentage points, indicating that the regenerated wastewater had a significant role in promoting the granulation of anaerobic sludge.

INFLUENCE OF LUBRICATION IN COLD ROLLING PROCESS OF IF STEEL ON MINIMUM ROLLED THICKNESS OF STRIP AND POWER OF MAIN MOTOR

2024, 55(3):  138-142. 

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A commercial metal working fluid and a self-developed rolling fluid were used to lubricate the IF steel sheet during cold rolling, and the influence of lubricant on reducing the minimum rolled thickness and the main motor power in the IF steel rolling process was explored by theoretical calculation and experiment. The results showed that the minimum rolled thickness of the rolled piece and the main motor power and energy consumption could be effectively reduced by lubrication. The minimum rolling thickness was reduced by 17.4% and 30.4% by LP-1 and LP-2 lubrication, respectively. After nine passes of rolling, the total power decreased by 2.63% and 3.35% by LP-1 and LP-2 lubrication, respectively. If the minimum rolled thickness of strip steel without lubrication was taken as the final rolled thickness, LP-1 and LP-2 lubrication could reduce one and two rolling passes, and the total power could be reduced by 8.61% and 15.31%, respectively. The friction coefficient of LP-2 lubrication was smaller than that of LP-1 lubrication, so LP-2 lubrication could get lower minimum rolled thickness and better effect of reducing main motor power.

INFLUENCE OF TEMPERATURE ON THE TRIBIOLOGICAL PROPERTIES OF LUBRICANT BY SRV TESTER

2024, 55(3):  143-147. 

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This paper introduced a self-developed test method for determining the anti-scuffing failure temperature of lubricants, which was a new development in the field of tribology performance evaluation. At the same time, the variation of friction coefficients with temperature of several lubricants and the determination of anti-scuffing failure temperature were evaluated by using the test method established in the study. The mechanism of the variation of tribological properties of typical samples with temperature was discussed in order to provide help and guidance for the researchers.

RESEARCH PROGRESS ON PREPARATION AND APPLICATION OF SiO2 COATED CORE-SHELL CATALYSTS

2024, 55(3):  148-153. 

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Core-shell materials, as a kind of composite catalyst, are composed of core and shell, which show excellent synergistic effect and new characteristics. SiO₂ is an ideal shell material for developing core-shell catalysts because of its advantages such as non-toxicity, chemical inertness, optical transparency, simplicity of modification, and low cost. In this paper, the preparation methods of SiO₂ coated core-shell catalysts, including the sol-gel approach, template method, self-assembly process, and surface deposition method were introduced in detail. Besides, the applications of SiO₂ coated core-shell catalysts in heterogeneous catalysis, such as shape selective catalysis, reducing the loss of active components, preventing the aggregation of nanoparticles and sintering were discussed. The future development trend of core-shell catalysts coated with SiO₂ was pointed out.

RESEARCH PROGRESS ON PREPARATION AND APPLICATION OF AMORPHOUS SILICA-ALUMINA MATERIALS

2024, 55(3):  154-161. 

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Amorphous silica-alumina (ASA) is a composite material formed by Al₂O₃ and SiO₂ with large pore size, pore volume and suitable acidity, which has been used in crude oil processing. The development of high performance ASA materials is of great significance in improving the catalyst activity and increasing the selectivity of target products. The effects of different preparation methods on the structure and acidity of ASA materials, the causes of the acidity of ASA materials and the influencing factors were analyzed. The applications of ASA materials in hydrocracking, catalytic cracking, and other catalytic reaction processes were investigated to provide guidelines for the preparation of high performance ASA materials. The main directions of future research on ASA materials were proposed in the light of current development trends.

ANALYSIS OF OIL-BASED TITANIUM DIOXIDE NANOFLUIDS FOR USE IN INSULATING OILS

2024, 55(3):  162-168. 

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The traditional insulating oil can not play a satisfactory role because of its poor viscosity, low oxidative stability, and poor biodegradability. Oil-based titanium dioxide nanofluids have been widely developed for their excellent alterating current and pulse breakdown properties, high electrical conductivity and good ageing resistance. However, the stability of the nanofluids is still unsatisfactory and many mechanisms remain to be clarified. Therefore, it is systematically summarized including the preparation, characterization, stabilization mechanisms, and key performance parameters of titanium dioxide nanofluids. Further more, the advantages and disadvantages of oil-based titanium dioxide nanofluids are compared. This work can provide the reference for this kind of material's follow-up development.