Table of Content

12 November 2021, Volume 52 Issue 11

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DEVELOPMENT OF RESIDUE DEEP HYDROTREATING TECHNOLOGY FOR PRODUCING HIGH QUALITY DEEP CATALYTIC CRACKING FEEDSTOCK

2021, 52(11):  1-7. 

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Using five different kinds of residue as raw materials, the residue deep hydrotreating technology was developed from different perspectives such as catalyst development, catalyst grading technology development, process condition optimization, and raw material adaptability investigation. The investigation showed that the activity of the newly developed catalysts was significantly higher than that of the conventional catalysts, and the reaction temperature was the most critical factor affecting the hydrogenation depth. Under the optimized catalyst grading and process conditions, the residue deep hydrotreating technology achieved high-efficiency removal of heteroatoms and a significant increase in hydrogen content, and also realized the directional conversion of the dominant hydrocarbon which can produce more chemicals. The results also showed that the atmospheric residue with high sulfur and low nitrogen was suitable to be used as the feedstock of the residue deep hydrotreating technology to produce high quality catalytic cracking feedstock.

RESEARCH ON FACTORS INFLUENCING THE COLOR OF HYDROTREATED DIESEL

2021, 52(11):  8-13. 

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The properties of diesels from different sources and the hydrogenated products were analyzed in detail, and the relationship between hydrocarbon composition and color of hydrotreated diesel with narrow distillation range was investigated. The influence of process conditions on the color materials of hydrotreated diesel was researched in a medium scale test unit. The results show that the color materials in the diesel fractions are mainly concentrated in the heavier fractions, and the main color materials in hydrotreated diesel are pyrene and fluoranthrene. By increasing hydrogen partial pressure or hydrogen-oil ratio, the hydrogenation equilibrium of PAHs can be broken, resulting in the product of light color.

AFFECTING FACTORS AND COUNTERMEASURE FOR LONG-TERM STABLE OPERATION OF HYDTROTREATING UNIT

2021, 52(11):  14-18. 

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Based on both vacuum gas oil hydrotreating unit operating data and the spent catalysts analysis result, the key factors affecting the long-term stable operation of the vacuum gas oil hydrotreating units are analyzed and discussed. The results show that the asphaltene content in the feedstock is the key factor affecting the long-term stable operation of heavy oil hydrotreating unit. By designing the reasonable catalysts grading system and operating condition for the different feedstocks, the coke deposited on the catalysts surface could reach the dynamic equilibrium and the hydrotreating unit catalysts could not deactivate in the whole cycle length. Based on the VGO hydrotreating unit operating experience, the countermeasures to realize long-term stable operation of heavy oil and diesel fraction hydrotreating unit are put forward.

INDUSTRIAL APPLICATION OF PURIFICATION TECHNOLOGY OF REACTION EFFLUENT FROM SINOALKY ALKYLATION PROCESS

2021, 52(11):  19-23. 

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The SINOALKY sulfuric acid alkylation technology was adopted in a 200 kt/a alkylation unit of SINOPEC Luoyang Company. Compared with the traditional sulfuric acid alkylation technology, the SINOALKY technology adopts high-efficiency acid-hydrocarbon coalescence and separation technology in the refining technology of the reaction effluent, and eliminates the process of alkaline washing and water washing, which is very different from the traditional technology. The principle, characteristics and advantages of the purification technology of SINOALKY alkylation reaction effluent are introduced, and its industrial application is studied. In 2020, the alkylation unit of SINOPEC Luoyang Company used SINOALKY reaction effluent purification technology. The results show that the sulfur content of the reaction product can be controlled below 10 μg/g before fractionation, and the quality of alkylate products are all qualified. Compared with traditional alkaline washing and water washing purification technology, the SINOALKY refining technology reduces the energy consumption by 181.71 MJ/t and the production cost by 2 444 100 CNY/a, and has achieved good industrial application effect.

RESEARCH AND DEVELOPMENT OF FLEXIBLE FILTER TECHNOLOGY FOR FCC SLURRY

2021, 52(11):  24-29. 

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The fluid catalytic cracking (FCC) slurry was treated with different kinds of flexible filter materials developed indepently to remove solid particles. The effects of filter temperature and feed rate on the removal of solid particles in FCC slurry, and the performance, stability and adaptability of the flexible filter material to different FCC slurries were investigated. The results show that the third-generation filter has the highest solid removal rate, the second-generation filter has slightly higher solid removal rate than the first-generation filter, and the increasing filter temperature, the decreasing feed rate, the desolidation period increases. The third generation of flexible filter material can adapt to high viscosity and high solid particle content of the FCC slurry, and has stable performance and good regeneration performance. With the third generation of flexible filter after mutiple regeneration, the mass fraction of Al and Si in the desolidated slurry is less than 10 μg/g, and the initial pressure drop of the filter is basically the same.

STEAM CRACKING PERFORMANCE OF FOOTS OIL / HYDROCRACKING TAIL OIL MIXED FEEDSTOCK

2021, 52(11):  30-33. 

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The steam cracking performance of the mixture was studied by using the mixture of foots oil and hydrocracking tail oil as feedstock of steam cracking unit for producing ethylene, on a steam cracking simulation test device. The effects of foots oil amount, cracking temperature and water/oil mass ratio on the yield of target olefins were investigated. The results show that the optimum steam cracking conditions are as follows: the mass fraction of foots oil is 20%, the cracking temperature is 820 ℃, and the water/oil mass ratio is 0.75. Under these conditions, the yields of ethylene and propylene were 34.3% and 14.65%, respectively.

FACTORS AFFECTING OCTANE NUMBER OF ALKYLATE FROM LOW TEMPERATURE SULFURIC ACID ALKYLATION PROCESS AND THEIR OPTIMIZATION

2021, 52(11):  34-37. 

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The alkylate oil produced by low temperature sulfuric acid alkylation unit has the characteristics of high octane number, low sulfur and no olefin. The important factors affecting the octane number of alkylate were analyzed by comparing the composition of olefin, the concentration of isobutane, the concentration of acid, the amount of acid circulation and octane number of alkylate oil in daily raw materials, and corresponding control methods and optimization measures were put forward to improve the octane number of alkylate and to achieve the optimization purpose.

INDUSTRIAL APPLICATION OF GAS-PHASE ALKYLATION TECHNOLOGY SGEB FOR DRY GAS TO ETHYLBENZENE

2021, 52(11):  38-41. 

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The gas-phase dry gas to ethylbenzene technology (SGEB) was adopted in a new 120 kt/a ethylbenzene unit in CNOOC Dongfang Petrochemical Co.,Ltd. The technology contains alkylation and transalkylation catalysts, five-stage adiabatic fixed-bed alkylation reactor, the FCC dry gas depropylene system, the installation of the propylbenzene column and the non-aromatic column etc., having the advantages of simplified process flow, investment-saving and low energy consumption. The unit uses FCC dry gas and purchased benzene as raw materials. The purity of ethylbenzene is 99.84%, the content of xylene is 0.06%, the conversion rate of ethylene is 98.94%, the conversion rate of diethylbenzene is 74.7%,and the economic benefit is very good.

EFFECT OF XYLENE ISOMERIZATION CATALYST PERFORMANCE ON THE OPERATION OF AROMATICS COMPLEX

2021, 52(11):  42-47. 

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Using iterative analysis algorithm, the influence on the operation of aromatics complex by catalyst performance under different process operating conditions is compared and analyzed. By adjusting the operation of the xylene isomerization reactor to control the catalyst performance, and the degree of influence of performance indicators such as isomerization activity (PX/X), ethylbenzene conversion (EBC) and yield on the circuit of the complex unit was independently investigated. The calculation results show that the composition and structure of the fresh feed have the greatest impact on the operating parameters such as the yield and load of the unit. The feedstockfrom disproportionationunitis generally better than that from the reformingunit. The EB conversion technologyis highlyadaptable to different feedstock. The EB dealkylation technology should be the first choice for disproportionation stream. The EB dealkylation process loop is more stable, and the three performances of the catalyst have a relatively small impact on the loop iteration results. In the investigated range, the loop fluctuation range is less than 3%. The EB conversion technology is liable to beaffected by the EBC activity of the catalyst, which has an impact of about 8% on various parameters of the unit, while the impact range of the PX/X is only 3%.

APPLICATION OF C₅/C₆ ISOMERIZATION CATALYST RISO-C IN 80 kt/a ISOMERIZATION UNIT

2021, 52(11):  48-51. 

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To meet China Ⅵ gasoline standard, the PetroChina Yumen Oilfield Branch Company Oil Refining and Petrochemical General Plant completed the technical innovation of original C₅/C₆ isomerization unit, added the feedstock and circulating hydrogen drying and regeneration system, and replaced the original catalyst by the solid super-acid catalyst RISO-C. This unit could convert the reforming topped oil to gasoline blending component with high octane number, which effectively reduces the olefins and aromatics content of China Ⅵ gasoline pool. The revamped unit was started successfully in November, 2019, and the results of performance test of unit show that the isomerization ratio of C₅ is more than 68%, the isomerization ratio of C₆ is more than 83%, reaching the target of design and demonstrating the excellent performance of catalyst, which can meet the need of long term run of unit.

APPLICATION OF PETROLEUM WAX IN THERMAL MANAGEMENT AS RAW MATERIALS OF PHASE CHANGE WAX

Luo Wangqun

2021, 52(11):  52-55. 

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Combined with the market demand and the actual capacity of domestic industrial production units, the experimental study on the use of petroleum wax as raw material of phase change wax was carried out, in order to improve the economic benefits of petroleum wax products. The results showed that when the purity (w) of main paraffin reached more than 99% for the liquid wax and the melting range was less than 15 ℃ for the low melting point wax, the mass fraction of normal paraffin was more than 90% for common wax, the phase change enthalpy could meet the application requirements. The applications of phase change materials in different fields were also investigated.

TRIBOLOGICAL PROPERTIES OF MUSCOVITE AND KAOLIN AS ADDITIVES FOR PTFE GREASE

2021, 52(11):  56-63. 

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Muscovite and kaolin modified by oleic acid were prepared and used as additives for PTFE grease. The muscovite and kaolin before and after modification were characterized by IR. The volume resistivity, friction surface morphology and friction and wear properties of PTFE grease with muscovite or kaolin were measured by volume resistivity tester, scanning electron microscope (SEM) and current carrying reciprocating friction and wear tester. The results show that the friction reducing property of muscovite modified by oleic acid is the best, while the anti-wear property of kaolin modified by oleic acid is the best. Under the condition of current carrying, the oil modified kaolin additive has the best comprehensive properties of lubrication and insulation, and has the largest contact resistance.

RAPID GASOLINE RECOGNITION MODEL BASED ON PORTABLE RAMAN SPECTROSCOPY

2021, 52(11):  64-69. 

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In order to achieve the rapid field detection of gasoline brand and research octane number (RON), the spectral signals of 113 gasoline samples were collected by a portable Raman spectrometer. Then the gasoline brand model was respectively established by principal component analysis and partial least squares discriminant analysis, and the gasoline RON model was established by partial least squares method. The results show that the gasoline brand model based on the baseline-corrected spectral data treated by principal component analysis and derivation, the accuracy of sample classification can reach 92.92%, while the positive rate of the PLS-DA model is above 95%, which is better for distinguishing 92# and 95# gasoline. The gasoline RON rapid prediction model based on partial least squares, the prediction set correlation coefficient is 0.8927, and the root mean square error of prediction is 0.6096, which shows that the predicted value has a good correlation with the actual value.

CORRELATIONOF DIFFERENT TEST METHODS AND CONDITIONS FOR TRIBOLOGICAL PROPERTIES OF MARINE STEAM TURBINE OIL

2021, 52(11):  70-77. 

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Taking marine steam turbine oils as the research object, the four-ball testing machine, FZG gear testing machine and SRV-IV friction and wear testing machine were used to investigate its tribological performance under different "four-ball method" standard test methods and different test conditions. The qualitative analysis and Pearson coefficient regression method were adopted to study the correlation between the tribological properties of marine steam turbine oils by "four-ball method" and the evaluation results of "FZG method" and "SRV method". The results show that when the "four-ball method" is used to evaluate the anti-wear properties of marine steam turbine oils, the test load and the test machine speed are the key factors affecting the oil anti-wear performance; qualitative analysis and Pearson coefficient regression show that according to SH/T 0189-2017 standard method, when the test load is 147 N and the test machine speed is 1 200 r/min, the tribological performance of the test oil obtained by the four-ball test is significantly correlated with the results of ASTM D4172-94 and ГOST 9490-75, showing a very strong linear positive correlation with SH/T 0847-2010（SRV test）. At the same time, the bearing capacity of the test oil tested by GB/T 3142-2019 has a highly linear positive correlation with the FZG test results.

APPLICATION OF KERAS-BASED NEURAL NETWORK TECHNOLOGY IN DIESEL ULTRA-DEEP HYDROREFINING

2021, 52(11):  78-86. 

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NiMo，CoMo and NiMoW catalysts were evaluated with different diesel feedstocks in a high-throughput reactor under the conditions of a temperature of 300-360 ℃，a pressure of 4.4-7.4 MPa，a LHSV of 0.75-12 h^-1 and a volume ratio of hydrogen to oil of 200-800. The Neural network technology based on Keras was used to establish diesel ultra-deep hydrorefining models suitable for three different catalysts，and the prediction of sulfur，nitrogen，monocylic aromatics and polycyclic aromatics content in diesel products was realized. The results show that these models have good prediction performance and generalization ability. The average relative error of the prediction of sulfur and nitrogen content in the product is less than 10%，and the average relative error of the prediction of monocylic and polycyclic aromatics content is less than 3% and 6%，respectively. These models can be used to optimize the process conditions of the three catalysts simultaneously，and the range of process conditions for different catalysts can be determined under the premise that the sulfur and polycyclic aromatics content of diesel products can satisfy the requirements of China Ⅵ Standard.

RESEARCH ON RECEDING HORIZON SCHEDULING METHOD OF CRUDE OIL PIPELINE TRANSPORTATION CONSIDERING ONLINE BLENDING

2021, 52(11):  87-92. 

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Most crude oil scheduling schemes are compiled by personnel experience or mathematical programming methods in refinery industries. It is difficult to meet the requirements of the crude oil online blending or to reduce the scale of optimization by these methods in real practice. For the typical crude oil pipeline scheduling process, a receding horizon scheduling method was developed in which crude oil blending demands were considered. The mixed-integer programming was employed first to establish the crude oil scheduling model, and then the blending demands were incorporated into the constraints as well as the objective function. By dividing the whole scheduling period into several short ones, the receding horizon optimization was implemented to solve this problem. The results indicate that with the scheduling period of 168 h, the crude oil pipeline scheduling problem can be successfully resolved by the proposed method under the condition of dynamic crude oil blending formula. Obviously, this method can make the crude oil scheduling match the crude oil blending demand much better, and the more economical crude oil scheduling scheme can be found quickly, thereby greatly promoting the economic efficiency of the refineries.

OPERATION SIMULATION AND ANALYSIS ON THE HIGH SEPARATION PROCESS IN COAL DIRECTLY LIQUEFIED UNITS

2021, 52(11):  93-101. 

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In view of the problem that the oil yield of the first industrial direct coal liquefaction unit is lower than the design value during commercial operation, according to the operation data of the coal liquefaction unit under the best working condition, the appropriate thermodynamic physical property model is selected through comparison, and using HYSYS application in Aspen One software, the operation effects of high-pressure and medium-pressure flash separation processes are simulated to explore the methods to improve the yield of liquefied oil in coal liquefaction unit. The existing high-pressure separation and medium pressure separation are highly sensitive, which makes the hot high-pressure separator and hot medium pressure separator liable to cause entrainment, leading to the reduction of the oil extraction rate and the yield of liquefied oil. In view of this problem, the optimization suggestions on the process and equipment design of hot high-pressure separator and hot medium pressure separator are put forward. At the same time, it is suggested to add hydraulic turbine between the two flash tanks to recover power, reduce the friction and thinning of pipeline and improve the operation stability.

QUANTUM CHEMICAL STUDY ON THE STRUCTURE-ACTIVITY RELATIONSHIP OF MANNICH BASE AS CORROSION INHIBITOR

2021, 52(11):  102-110. 

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Three kinds of Mannich base corrosion inhibitors BK1, BK2 and BK3 (collectively referred to as BK group corrosion inhibitors) were synthesized by reacting hexylamine, phenylmethylamine and cyclohexylamine with acetone and formaldehyde, respectively. Three kinds of Mannich base corrosion inhibitors (collectively referred to as PA group corrosion inhibitors) were synthesized by reacting hexylamine, phenylmethylamine and cyclohexylamine with acetone and formaldehyde, respectively. In addition, double-Mannich base corrosion inhibitor D1 was synthesized by reacting BK2 with acetone and formaldehyde as a precursor. Double-mannich base corrosion inhibitor D2 was synthesized by reacting PA1 with cyclohexylmethanone and formaldehyde as precursor. The corrosion inhibition of N80 specimens in acidic media was investigated with the eight corrosion inhibitors mentioned above. The quantum chemical parameters of the Mannich base molecules were calculated using density functional theory. The results of grey correlation analysis show that the energy of the lowest unoccupied molecular orbital (E_LUMO)，the energy gap(ΔE)，dipole moment(μ)，isotropic average polarizability(α) and negative electrostatic potential of van der Waals surface area (A_S-) had the good correlation with the inhibition rate of Mannich base. The grey correlation degrees ranged from 0.736 to 0.891 and the linear determination coefficients ranged from 0.556 to 0.968. It was concluded that some quantum parameters，such as ELUMO and ΔE of the BK series were lower than those of the PA series，while their μ，α and A_S- were higher than those of the PA series. Compared to the hexyl group of the BK1 and the cyclohexyl group of BK3，the phenylmethyl group of the BK2 increased the polarizability and the area of the negative electrostatic potential，resulting in α and A_S- BK2 > BK1 > BK3. The E_LUMO and ΔE of D1 and D2，due to the second β-carbonyl group，were lower than those of BK2 and PA1. The best corrosion inhibition efficiency was obtained for BK2 in the BK series，and the corrosion inhibition increased with further synthesis to obtain double Mannich base D1. The corrosion inhibition effect was further increased from 99.2 %to 99.4% for N80 specimens under the same conditions.

OPTIMIZATION OF SULFUR RECOVERY TECHNOLOGY FROM LOW H₂S CONCENTRATION ACID GAS

2021, 52(11):  111-115. 

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At present, there are problems such as over-standard SO₂ emission from the sulfur recovery unit of a natural gas purification plant in Jingbian Gas Field. In order to solve this problem, this article aims to improve the conversion rate of H₂S and reduce the emission of SO₂. On the basis of the traditional Clinsulf-DO process, the optimization design is carried out from the aspects of process flow and catalyst. As a result, a dual-reactor selective sulfur oxidation recovery process plus tail gas alkaline washing technology is formed. In this process, domestic catalysts HS-35 and HS-38 are used for catalytic reaction in the the first and second reactors, respectively. The results of calibration data show that the total sulfur conversion rate of the retrofitted plant has been increased from 80.27% of the original process to over 94%. At the same time, the mass concentration of SO₂ in the emitted tail gas is reduced to below 100 mg/m³, which can meet the requirements of the new environmental protection regulations "Petroleum Refining Industry Pollutant Emission Standard (GB31570-2015)". This technology has good industrial application effects, so it can provide a certain reference for sulfur recovery from low H₂S acid gas to satisfy gas emission standards.

RESEARCH PROGRESS ON FACORS AFFECTING DEEP CATALYTIC CRACKING OF HEAVY OIL TO LIGHT OLEFIN

2021, 52(11):  116-123. 

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The great demand of chemical raw material such as ethylene and propylene and moderating of oil consumption increase drive the petrochemical industry to a new direction of integration of refinery and petrochemical where the technology of producing light olefins from heavy oil deep catalytic cracking deserves a place. From the perspective of reaction mechanism, the effect of feedstock property, catalyst, reactor type, and operating conditions on the product distribution is summarized, and the challenges on the progress of deep catalytic cracking are prospected.