Table of Content

12 February 2023, Volume 54 Issue 2

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DEVELOPMENT AND COMMERCIAL APPLICATION OF SOLID SUPERACID CATALYST RISO-C FOR C₅/C₆ ISOMERIZATION

2023, 54(2):  1-8. 

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Ultra fine zirconia was synthesized by hydrothermal synthesis method and used as building blocks for preparing Pt/SO₄^2--ZrO₂ catalyst with high specific surface area.The acidity and thermal stability of Pt/SO₄^2--ZrO₂ was further enhanced by introducing alumina as modifier. The solid superacid isomerization catalyst RISO-C with high activity, high selectivity, high stability and excellent regeneration performance was developed and applied in the first C₅/C₆ isomerizaiton plant of solid superacid in China. The results of industrial application showed that using topped oil of reformer as feed, under the reaction conditions of reactor inlet temperature of 170 ℃, gas-liquid separator pressure of 1.5 MPa, mass space velocity of 1.26 h^-1 and H₂/oil molar ratio of 1.95, RISO-C catalyst had excellent activity and stability. The isomerization rate of C₅ was higher than 70%, and the isomerization rate of C₆ was higher than 85%,the research octane number of stabilized gasoline reached 85, and its application prospect was good.

STUDY ON CATALYTIC PERFORMANCE OF Ni@SiO₂ FOR DICYCLOPENTADIENE HYDROGENATION

2023, 54(2):  9-15. 

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In order to realize the continuous production of high-density jet fuel JP-10, the efficient hydrogenation of dicylcopentadiene (DCPD) to produce endo-tetrahydrodicylcopentadiene (endo-THDCPD) is particularly critical. Therefore, the reaction system of hydrogenation of DCPD to endo-THDCPD was studied. Based on the structural characteristics of nickel silicate, Ni@SiO₂ catalysts with mesopores, Ni(OH)⁺ and nanoscale dispersed Ni were designed to promote the diffusion, adsorption and hydrogenation of DCPD, respectively. The results showed that Ni@SiO₂ could be used as catalyst for hydrogenation of DCPD at room temperature. The hydrogenation activity of Ni@SiO₂ was much higher than that of Raney Ni, and the yield of endo-THDCPD was up to 99.1%. When the reaction temperature was 20-120 ℃, the reaction pressure was 5 MPa, the liquid hourly space velocity was 1 h^-1, and the volume ratio of hydrogen to oil was 100, Ni@SiO₂ also had excellent hydrogenation stability, the conversion of DCPD was 99.9% and the endo-THDCPD yield was more than 92% after running 2 400 h.

THE EFFECT OF NITROGEN POLLUTION ON SEMI-REGENERATIVE REFORMING CATALYST AND DEVICE

2023, 54(2):  16-21. 

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The source of nitrogen, the mechanism of nitrogen poisoning, the influence of nitrogen on catalyst, equipment and device were analyzed according to nitrogen poisoning of semi-regeneration reforming catalysts in three different refineries, and the measures to solve nitrogen poisoning were put forward, such as raw material control, catalyst selection, and increasing liquid phase dechlorination. When the reforming catalyst was polluted by nitrogen, it was necessary to increase the chlorine injection amount temporarily to compensate for the chlorine loss of the catalyst, but it would aggravate the corrosion of the equipment and device. Nitrogen pollution is temporary, and the activity of the catalyst will be restored once the reforming feed met the index requirements. The reason of the high nitrogen content should be found out as soon as possible after nitrogen pollution, and the nitrogen pollution should be eliminated in time. Otherwise, ammonium chloride will be generated at the low temperature part in the system, which will affect the normal operation of the equipment. The most effective measure to prevent the crystallization of ammonium salt is to strictly control the nitrogen content of reforming oil less than 0.5 ug/g in the pre-hydrogenation system.

PERFORMANCE ANALYSIS OF CONTINUOUS REFORMING CATALYST AT THE BEGINNING AND END OF OPERATION

2023, 54(2):  22-26. 

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The performance change of continuous reforming catalyst PS-Ⅶ in 1.39 Mt/a continuous reforming unit of SINOPEC Yangzi Petrochemical Co., Ltd. was introduced. The structure and composition of the catalysts were analyzed by TEM and elemental analysis, and the selectivity and activity of the catalysts were simulated by R-sim software. Based on the change of product distribution and operating conditions, the economy of catalyst operation was analyzed. The results showed that the specific surface area of catalyst reduced to 149 m²/g at the end of operation due to the limitation of the first generation regeneration technology and the inevitable accumulation of Fe, the crushing strength reduced to 42 N/grain, the catalyst activity reduced by 4.7℃, the yield of C₆+ liquid and the yield of aromatics reduced by 1.33 percentage points and 1.25 percentage points respectively in the reforming unit, and the catalyst reached the target of changing agent.

HYDROCHLORINATION OF ACETYLENE CATALYZED BY COPPER PYRIDINIUM CHLORIDE SUPPORTED ON ACTIVATED CARBON

2023, 54(2):  27-34. 

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The copper pyridinium chloride catalyst supported on activated carbon was prepared by the impregnation method. The catalytic performance of the catalyst in the acetylene hydrochlorination reaction was tested and compared with that of the catalyst of copper chloride supported on activated carbon. Under the conditions of reaction temperature of 330 ℃, the volume space velocity of C₂H₂ of 100 h^-1, the molar ratio of HCl to C₂H₂ of 1.05, and the content of copper pyridinium chloride of 15%, the conversion rate of acetylene reached 64%, and the selectivity of vinyl chloride was more than 95%. By means of SEM, XRD, XPS, TG, BET and TPD, It was found that the strong adsorption of hydrogen chloride and the good stability of Cu²⁺ were the key factors for the high activity of the catalyst, and the main reason for the deactivation of the copper pyridinium chloride catalyst was the deposition of carbon on its surface, the main reasons for deactivation of copper chloride catalyst were coke deposition and Cu²⁺ reduction. The mechanism of acetylene hydrochlorination catalyzed by copper pyridinium chloride was studied by using molecular simulation software.

INDUSTRIAL PRODUCTION AND PERFORMANCE OF HIGH-QUALITY CLASS API Ⅲ BASE OIL

2023, 54(2):  35-39. 

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CNOOC Oil & Gas (Taizhou) Petrochemical Co.,Ltd. used the vacuum fraction of South China Sea crude oil as feedstock and the existing base oil production unit, and adopted a full hydrogenation process, two kinds of high quality API III base oils, TZ-HVI 6 and TZ-HVI 4, were produced by adjusting the properties of raw oil and optimizing process parameters. The results of product property analysis showed that API Ⅲ base oil produced by Taizhou Petrochemical Company had high viscosity index, high content of saturated hydrocarbon, low content of sulfur, low pour point and excellent dynamic viscosity at low temperature, the related property parameters were similar to the same kind mainstream imported products, and some performance indexes were even better than YUBASE series base oils produced by SK Company. Furthermore, SP 5W-30 gasoline engine oil was produced by using API III group base oil TZ-HVI 6 and TZ-HVI 4 produced by Taizhou Petrochemical Company, its key physical and chemical indexes, such as foam resistance, sulfur content, phosphorus content, high temperature and high shear viscosity, evaporation loss and sulfate ash content, could meet ACEA C3 standard.

CAUSE ANALYSIS AND SOLUTION FOR PRESSURE DROP INCREASE OF REGENERATOR IN CONTINUOUS CATALYTIC REFORMING UNIT

2023, 54(2):  40-44. 

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The increase of pressure drop of regenerator in continuous catalytic reforming unit will directly affect the normal production of the unit. In view of the high pressure drop caused by the internal strainer blockage of the regenerator in a continuous catalytic reforming unit in a domestic refinery, the reasons for the increase of pressure drop were analyzed from the aspects of the operating process of the regeneration system, structural features of the regenerator and manufacturing process. The results showed that excessive wear of catalyst and improper operation of production process were the direct causes of internal strainer blockage and pressure drop increase, while the inherent defects of axial screen structure and manufacturing process used in the internal strainer were the indirect causes. By cleaning the internal strainer, optimizing the operation of drying system and elutriating system, the hidden trouble of internal strainer blockage of the regenerator was eliminated.

EFFECT OF CO₂ ON TAIL GAS ABSORPTION AND SOLVENT REGENERATION OF SULFUR RECOVERY UNIT

2023, 54(2):  45-50. 

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The main difference between the tail gas of sulfur recovery units in refinery and coal chemical industry is the difference of CO₂ content. In this paper, the hydrogenation reduction and absorption process were used, and the solvent was methyl diethanolamine (MDEA) solution. Three types of typical sulfur recovery tail gas from refinery sulfur recovery unit, coal chemical oxygen-enriched sulfur recovery unit and coal chemical pure oxygen sulfur recovery unit were studied, and the effects of CO₂ on the absorption of tail gas and the regeneration of solvent were investigated. The results showed that the CO₂ affected the absorption of H₂S by MDEA solution. With the increase of content of CO₂, the required circulation amount of MDEA solution and the concentration of MDEA solution increased, steam consumption also increased during solvent regeneration. For the tail gas of sulfur recovery from coal chemical industry with high CO₂ content, high concentration and high efficient solvent should be used to reduce the amount of solution circulation and steam consumption, and to reduce the absolute amount of acid gas returning to sulfur making furnace, or choose a short-process sulfur recovery process.

ADSORPTION DESULFURIZATION OF THIOPHENE FROM HYDROGEN BY Cu-MODIFIED ACTIVATED CARBON

2023, 54(2):  51-57. 

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Using activated carbon (AC) as a carrier, different metal-modified activated carbon adsorbents were prepared by equal volume impregnation method for the removal of thiophene in hydrogen, and the thiophene removal properties of transition metal modified adsorbents and Cu modified adsorbents with different contents were investigated by using fixed bed dynamic adsorption method. The adsorbents were characterized and analyzed by means of N2 physical adsorption- desorption (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The results showed that the activated carbon had the best desulfurization ability when the copper loading was 3%, and the permeation time of the thiophene was 22 h, which was 7 h longer than that of the unmodified activated carbon adsorbent. After modification of activated carbon with Cu, the porous structure of activated carbon still remained abundant, but the specific surface area and pore volume decreased, and the distribution of the active component CuO on the surface of the adsorbent was changed, it could promote the adsorption of thiophene by the modified adsorbent and improve the adsorption capacity of thiophene.

TWO-DIMENSIONAL SIMULATION OF THE REACTION MECHANISM OF ETHANE-PROPANE MIXED CRACKING

2023, 54(2):  58-64. 

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Using FLUENT software to construct one dimensional model and two dimensional models of ethane and propane mixture cracking reaction, the effects of radial flow rate, temperature, concentration distribution and free radical concentration distribution on the mixed cracking process of ethane and propane were simulated respectively. The results showed that the transfer process was coupled with the cracking process, and the cracking temperature of alkanes was decreased by radial diffusion. The concentrations of CH₄ and C₂H₄ in 2-D simulation were higher than those in 1-D simulation, while the concentrations of H₂, C₂H₆ and C₃H₆ were slightly lower. The mixed cracking of ethane and propane was mainly initiated by the chain initiation of propane, and both ethane and propane took part in the chain propagation process. During ethane and propane mixture cracking process, there were free radicals H·, CH₃·, C₂H₅·, i-C₃H₇· and n-C₃H₇·in the system. The concentrations of free radicals C₂H₅·, i-C₃H₇· and n-C₃H₇· need to be accumulated before olefin could be formed. Ethylene was mainly generated by C₂H₅· and n-C₃H₇· and propylene was mainly generated by i-C₃H₇· and n-C₃H₇·.

DETERMINATION OF SEMI-VOLATILE ORGANIC COMPOUNDS IN REFINERY WASTE CATALYST AND EVALUATION OF THEIR HAZARDOUS WASTE CHARACTERISTICS

2023, 54(2):  65-70. 

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A quantitative analysis method was established for the extraction of semi-volatile organic compounds from refinery waste catalysts by pressurized fluid extraction with dichloromethane/ acetone as extraction solvent. The mixture of nitric acid and sulfuric acid was used to prepare the leaching solution, and the quantity was determined by GC-MS combined with internal standard curve method. The detection limit, linearity, repeatability and recovery rate of the established method were investigated. The results showed that the method could be used for the detection of semi-volatile organic compounds in the organic extraction solution and leaching solution of waste catalyst. Three typical refinery waste catalysts from six different petrochemical companies were selected and their organic extracts and volatile organic compound were analyzed and compared. The concentrations of semi-volatile organic compounds in organic extracts and leachates were below the current limit value for hazardous waste in the series standards, providing a scientific basis for management decision on the disposal of refinery waste catalyst and support for petrochemical enterprises to prevent environmental risk.

RAPID DETERMINATION OF HARMFUL ELEMENTS IN GASOLINE BY 3D-PMEDXRF

2023, 54(2):  71-76. 

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A 3D fully polarized monochromatic energy dispersive X-ray fluorescence spectroscopy (3D-PMEDXRF) was developed for the determination of metal elements (Mn, Fe, Pb) and nonmetal (Si, S, Cl) in automotive gasoline, and the repeatability and accuracy of the method were also investigated. The results showed the mass fraction of six elements in motor gasoline had a good linear relationship in the range of 0-50 μg/g, and the lower detection limit of the each element could reach 1 μg/g, the relative standard deviation (RSD) of the results of repeated determination for 6 times was less than 6%, and the recovery rates were between 95%～105%, which could meet the requirements of analysis of silicon, sulfur, chlorine, manganese, iron and lead in gasoline. This method could be used to detect 6 kinds of elements in automobile gasoline at the same time, and the analysis efficiency can be improved effectively.

APPLICATION OF COMPRESSION RATIO METHOD IN THE DETERMINATION OF CETANE NUMBER OF DIESEL FUEL

2023, 54(2):  77-81. 

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By using the standard fuels and the corresponding air volume, the power function equation of "cetane number-air volume" was summarized through big data calculation and evaluation, the cetane number and air volume was measured by FCD compression ratio method, and the cetane number of the diesel fuel sample was obtained by checking the cetane number of the sample. There was no significant difference between FCD compression ratio method, CFR-ASTM method and FCD interpolation method. Comparing FCD (including FCD compression ratio method and FCD interpolation method) with CFR-ASTM method, FCD method could realize bi-directional forward and inverse adjustment of air volume; compared with the FCD interpolation method, the FCD compression ratio method could find the cetane number of the diesel sample in the "cetane number-air volume meter", but the FCD interpolation method must test two standard fuel air volumes (the sample air volume must be within the range of two standard fuel air volumes) through the interpolation method to calculate the cetane number of the sample. The diesel cetane number determination by FCD compression ratio method had high precision and repeatability.

ECOLOGICAL FOOTPRINT ESTIMATION AND INFLUENCING FACTORS OF LUBRICATING OIL IN CHINA

2023, 54(2):  82-89. 

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The ecological footprint of lubricating oil refers to the area of forest and grassland used to absorb CO₂ emitted by the combustion of lubricating oil. Based on the carbon cycle, the ecological footprint of Chinese lubricating oil was calculated and the partial least-squares regression model was used to study the main driving factors affecting the ecological footprint of lubricating oil. The results showed that the ecological footprint of Chinese lubricating oil increased year by year from 2014 to 2019. The main driving factors affecting lubricating oil ecological footprint were civilian vehicle holdings and the secondary sector of the gross domestic product (GDP), and the ecological footprint of Chinese lubricating oil increased by 15.11% and 15.08% for each 1% increase in the number of civil cars and the GDP respectively. This was followed by crude oil processing, per capita disposable income of urban households, per capita consumption of urban households and per capita consumption of transportation and communication, all of which increased by 1%, the ecological footprint of lubricating oil increased by 14%. The least impact was the fuel price, which increased 1%, the ecological footprint of lubricating oil increased by 11.82%.

SYNTHESIS OF ZSM-5 ZEOLITE USING KAOLIN AS ALUMINUM SOURCE AND ITS CO₂ ADSORPTION PERFORMANCE

2023, 54(2):  90-99. 

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ZSM-5 molecular sieve has the unique crystal structure, which has shown excellent performance in the field of catalysis. At the same time, due to the uniform pore size distribution, the molecular sieves have strong internal polarity in their crystal holes, and show good adsorption performance, which can adsorb water and the most of toxic and harmful substances in air, it is a new type of adsorption material which can be regenerated and does not produce secondary pollution. Using thermal activation of kaolin as the aluminum source, the ratio of silica to alumina in the sample was adjusted by increasing the amount of external silica source in the synthetic gel. In the absence of inorganic alkali (NaOH), self-stacking ZSM-5 was efficiently synthesized by using tetrapropylammonium hydroxide (TPAOH) as the template under the interaction of organic template and crystal seeds, and it was used for CO₂ adsorption. The results showed that the optimum synthesis conditions were as follows: the mass fraction of crystalline seed was 3%, the template was TPAOH, n(TPAOH)/n(SiO₂) was 0.3, the crystallization temperature was 170℃, the crystallization time was 2 h, and the ratio of silicon to aluminum was 15. The adsorption of CO₂ on molecular sieve synthesized under the these conditions was better than that of the commercial ZSM-5 molecular sieve.

BLENDING METHOD OF LOW-SULFUR MARINE FUEL OIL BASED ON COMPATIBILITY PRINCIPLE

2023, 54(2):  100-107. 

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In order to solve the problem of quality stability of blended marine fuel oil products due to the poor compatibility of the feedstock, based on the compatibility principle, the matching proportion of each feedstock was calculated as the limiting condition of the fuel oil formula calculation, and then the optimized formula was obtained by taking the low cost as the objective function. The results showed that compared with the empirical formula, the optimized formula could improve the stability of the blended fuel oil, the spot test results of the fresh samples (0d) prepared by the optimized formula and the samples left for 15 days（15d）showed that the new samples had better stability, the gradient density difference of the blended samples (0d and 15d) was less than 10 kg/m³, and the spot test results were 2 grades. The fuel oil properties were stable after long-term storage.

RESEARCH PROGRESS ON PREPARATION METHODS OF HIERARCHICAL POROUS ZEOLITES

2023, 54(2):  108-116. 

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Zeolites have been widely used in petrochemical industry and fine chemical industry because of their unique topological structure, which endows them with excellent framework acidity, ion-exchange performance, stability and shape selectivity. However, the existence of crystal structure limits the pore size of zeolites to microporous size, which affects the diffusion efficiency and limits their scope of application in catalytic reactions. The diffusion distance can effectively shorten by constructing hierarchical porous structures in zeolites. So far, the strategies for constructing hierarchical porous structures could be divided into two strategies: "top-down" and "bottom-up". In this paper, the above two strategies and their effects on mesopores were summarized.

RESEARCH PROGRESS ON ACTIVE PHASE MORPHOLOGY AND STRUCTURE OF HYDROTREATING CATALYSTS

2023, 54(2):  117-125. 

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At present, based on the widely accepted Co (Ni)-Mo (W)-S active phase model, a systematic structure-activity relationship study has been carried out with the help of transmission electron microscope (TEM) observed morphology of active phase slabs on hydrotreating catalysts. It was found that morphology and structure of active phase slabs were closely related to the performance of the catalyst. With the development of characterization technology, more detailed structural information such as single atom and metal clusters could be observed by the aberration-corrected scanning transmission electron microscope (Cs-STEM), etc. Therefore, it was necessary to further systematically study the relationship of typical morphologies such as single atom, metal clusters and slabs and their impact on catalytic performance, so as to further clarify the structural characteristics of the ideal active phase, it also provided a theoretical basis for the efficient research and development of new hydrotreating catalysts.

RESEARCH PROGRESS IN THE SYNTHESIS OF TERT-BUTYLAMINE FROM ISOBUTYLENE AMINATION CATALYZED BY ZSM-5

2023, 54(2):  126-133. 

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The progress in the synthesis of tert-butylamine from isobutene in recent years was reviewed, and the research progress of the catalysts for the synthesis of tert-butylamine from isobutene catalyzed by ZSM-5 molecular sieve was mainly introduced from the aspects of the reaction process, modification and activity influence of ZSM-5 molecular sieve catalyst. The research direction of isobutene amination to tert-butylamine was summarized and prospected, which provided a reference for the optimization of ZSM-5 molecular sieve catalyst and the process development of isobutyl amination to tert-butylamine.

PROGRESS IN ALCOHOL RECOVERY TECHNOLOGY FROM ALCOHOL-WATER SYSTEM

2023, 54(2):  134-144. 

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Alcohols can be divided into high-carbon alcohols and low-carbon alcohols according to the number of carbon atoms contained in alcohols. The research progress of alcohol recovery technology in the alcohol-water system of high-carbon alcohol and low-carbon alcohol was reviewed in detail, and the advantages and disadvantages of each technology were compared in terms of energy consumption, raw material composition, purity and yield of product. The results showed that liquid-liquid extraction was the main technology for recovering high-carbon alcohol; due to the advantages of different technologies and the avoidance of their defects, the combined technology would become an important development direction to realize green and efficient energy saving of low carbon alcohol recovery technology in alcohol-water system. Chemical Looping Separation (CLS) had greater potential for polyol recovery from polyol-water system.