Table of Content

12 January 2020, Volume 51 Issue 1

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APPLICATION OF LTAG TECHNOLOGY FOR CONVERTING LCO TO HIGH OCTANE NUMBER GASOLINE

2020, 51(1):  1-6. 

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The LTAG technology was adopted in the VGO hydrotreating and catalytic cracking units of Fujian Refining and Petrochemical Company to produce high octane gasoline using LCO and VGO. LCO and VGO were mixed and hydrotreated firstly. After separation, hydrotreated LCO and hydrotreated VGO were fed at different positions in the lower part of the riser reactor, respectively. The results showed that compared with the conventional method of feeding mixed hydrotreated LCO and wax oil, the catalytic cracking apparent conversion rate of hydrotreated LCO was increased by 5.17 percentage points, apparent cracking rate was increased by 7.87 percentage points, and the apparent condensation rate was decreased by 2.01 percentage points; the contents of olefins and aromatics in gasoline were increased by 1.2 percentage points and 2.0 percentage points, respectively; the gasoline octane number, RON and MON, were increased by 1.4 units and 0.8 units, respectively, showing that LTAG technology is effective method to convert LCO into high octane number gasoline.

COLLABORATIVE OPTIMIZATION OF REFINING PROCESS BASED ON MEDIUM PRESSURE HYDRO-UPGRADING SCHEME

Ni Qianyin Liu Honglei

2020, 51(1):  7-13. 

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To increase the production of high value-added products and improve the benefits,SINOPEC Beijing Yanshan Company made collaborative optimization for the oil refining sector. The medium-pressure hydrocracking unit used a mixed feed blending with FCC diesel fraction, and ran in hydroupgrading scheme instead of hydrocracking, the upgraded diesel was returned to No.3 FCC unit for refining. At the same time, to improve the catalytic cracking feed properties, the CGO was fed into hydrocracking unit and no longer processed in the hydrotreating unit. After collaborative optimization, the cetane number of the medium-pressure hydrocracking diesel was increased by 7 units. The LPG yield of No.3 FCC was increased by about 1.96 percentage points, the gasoline yield was increased by 0.88 percentage points, and the total liquid was increased by 2.28 percentage points. The jet fuel density ( 20℃) of hydrocracking unit was reduced to 806 kg/m3 with a smoke point of 23.8 mm, and the BMCI of tail oil was reduced from 11.8 to 10.8. The saturated hydrocarbons of hydrotreated VGO were increased by 4.68 percentage points with a reduction of 5.96 percentage points of aromatics and 0.06 percentage points of nitrogen content, respectively, resulting in improved FCC feed quality. The jet fuel distillate of the medium pressure hydroupgrading unit was cycled back to FCC unit. Compared with the process of recycling back the upgraded diesel oil, the research octane number (RON) of the catalytic cracking gasoline was increased by 1.0 unit and the cetane number of the upgraded diesel oil was increased by 4.8 units. Through collaborative optimization of the whole refining scheme, the cetane number of vehicle diesel product of Yanshan petrochemical branch was reduced from 53.5 to 51.5, which solved the problem of excess quality.

PURIFICATION OF RAW MATERIALS FOR PENEX-DIH LOW TEMPERATURE ISOMERIZATION UNIT AND OPERATION

Hui GUO

2020, 51(1):  14-18. 

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Isomerate does not contain olefin and aromatics, so it is an ideal blending component of gasoline. UOP Penex-DIH (the isomerization reaction＋de-isohexane tower) process can be used to convert normal paraffin with lower octane number into isoparaffin with higher octane number to produce clean gasoline blending component with RON 85 or higher . The core of Penex-DIH isomerization unit is the Ⅰ-82 low-temperature catalyst. In order to avoid the permanent deactivation of Ⅰ-82 catalyst due to the influence of water, nitrogen, oxygen and other impurities in the feed, a purification unit for raw material of isomerization unit was added. The purification results showed that the impurity index can meet the requirements of the Penex-DIH isomerization reactor, ensuring the stability of the isomerization performance of the I-82 catalyst and the long-term operation.

CHARACTERISTICS AND OPERATION OF CATALYST REGENERATION TECHNOLOGY IN CONTINUOUS CATALYTIC REFORMING UNIT

2020, 51(1):  19-23. 

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The characteristics of catalyst regeneration technology of a 3.2 Mt/a continuous catalytic reforming unit in the aromatics project, which adopted the UOP patented Cyclemax continuous regeneration technology, were introduced. The start-up and operation of the plant were analyzed in terms of catalyst loading, catalyst circulation and chlorine absorption by ChlorsorbTM. The problems encountered in the start-up and operation, such as poor catalyst lifting, excessive catalyst dust, over-temperature of chlorine absorption tank, rapid decreases of catalyst strength and specific surface area, were described and analyzed. After using solid-phase dechlorination technology to replace the ChlorsorbTM, and adopting the spiral-wound tube heat exchanger for the mixed feed of the unit, the catalyst circulation system was smooth and the catalyst dust content reduced to less than 10 kg/d, the total temperature reduction of reforming reaction dropped to 316 ℃ when the inlet temperature of the reactor was not higher than 530 ℃. The catalyst showed excellent performance.

DEVELOPMENT AND APPLICATION OF TORH-1 CATALYST FOR OLEFIN REMOVAL FROM REFORMATE

2020, 51(1):  24-30. 

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A hydrofining catalyst TORH-1 was developed for removing olefin from reformate or from mixed aromatic hydrocarbons. The catalyst was supported on a new alumina base material with unique pore structure, Pd and Pt were used as main active components. The results of pilot test, industrial side line test and industrial application showed that TORH-1 catalyst had a good deolefin activity, selectivity，stability and adaptability to complex raw materials and could completely replace the industrial clay. TORH-1 catalyst does not need additional presulfidation to start-up and the starting method is simple, safe and green.

EFFECT OF SiO₂ DOPING ON DENITRATION PERFORMANCE OF V-Mo/TiO₂ CATALYSTS

2020, 51(1):  31-36. 

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The TiO₂-SiO₂ composite supports with different SiO2 doping amount were prepared by co-precipitation method, and then the active components V₂O₅ and MoO₃ were loaded on these composite supports by impregnation method to prepare V-Mo/TiO₂-SiO₂ catalysts (VMTS). The physical and chemical properties of the catalysts were characterized by XRD, SEM, BET, H₂-TPR techniques. The results showed that with the increase of SiO₂ doping amount, the XRD spectra of the VMTS catalysts not only presented SiO₂ diffraction peak, but also the diffraction peak of Anatase TiO₂. The active components, V₂O₅ and MoO₃, were in the form of amorphous or microcrystalline because of relatively low content. The reduction peak of SiO₂-doped catalyst moved toward the low temperature direction in H₂-TPR graph, the specific surface area and pore volume increased while the pore diameter decreased. Compared with the other catalysts, the VMTS-(0.2∶1)with the mass ratio of SiO₂/TiO2 of 0.2 catalyst had the lowest reduction peak temperature and the largest reduction peak area as well as the best redox capacity. The results of denitration efficiency evaluation showed that VMTS-(0.2:1) catalyst had the best denitration efficiency for the flue gas. When SO₂ was introduced into the flue gas, the decrease range of denitration efficiency of V-Mo/TiO₂-SiO₂ catalyst was lower than that of the undoped catalyst and all other tested catalysts with SiO₂ doped, indicating that doping SiO₂ is beneficial to the improvement of sulfur resistance of the catalyst.

MODIFICATION OF HIERARCHICAL ZSM-5 ZEOLITE WITH Mg AND Ce FOR METHYLATION OF BEZENE AND METHNOL

2020, 51(1):  37-42. 

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The influence of magnesium and cerium composite modification of hierarchical porous ZSM-5 on methylation of benzene with methanol was investigated. Magnesium nitrate and cerium nitrate were used as precursors. The effects of process conditions of the methylation were studied over the modified ZSM-5 catalyst. The results showed that at the conditions of 773K, 0.18 MPa, WHSV of 8 h-1, n（methanol）/n（benzene）= 0.9, the conversion rateof benzene was 51%, and the selectivity of toluene and xylene was greater than 90% over the Mg and Ce modified hierarchically ZSM-5. After 400 hours on stream, the catalysts still exhibited excellent stability, indicating its excellent industrial application value.

REDUCING ODOR OF LOW BASIC CALCIUM POLYISOBUTYLENE THIOPHOSPHONATE

Liu Yinong Duan Qinghua

2020, 51(1):  43-48. 

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hydrogen sulfide gas was emitted from heating up the calcium polyisobutylene thiophosphonate , which is the cause of its odor. The production of hydrogen sulfide when calcium sulphonate mixed with other additives was detected. It was found that more H2S was released when calcium polyisobutylene thiophosphonate was mixed with ZDDP and calcium alkyl benzene sulfonate. The influence of post-treatment process on the emission of hydrogen sulfide was investigated, and it was found that the emission of hydrogen sulfide decreased to different degrees after the addition of post-treatment agent, among which post-treatment agent X had the best effect. The effects of hydrolysis reaction time and calcification promoter type on the synthesis of calcium thiophosphonate were investigated. The improved synthetic process was helpful to satisfy the requirements of the performance of calcium thiophosphonate detergent. At the same time, the mass fraction of hydrogen sulfide released by the product was less than 20 μg. /g and met the requirements for safe use.

EFFECT OF PHOSPHOROUS-CONTAINING ANTI-WEAR AGENT ON MICRO PITTING RESISTANCE OF INDUSTRIAL GEAR OIL

2020, 51(1):  49-55. 

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The micropitting resistance of three phosphorous anti-wear agents with different structures of alkyl phosphate, aryl phosphate and phosphorodithioate in industrial gear oil was investigated by MPR and FZG testing machines. The results indicated that three kinds of anti-wear agents could improve the micropitting resistance of gear oils in different degrees. The thermal decomposition temperature of alkyl phosphite ester was high and the structure stability was good. In the oil testing, the micro-pitting area on the roller surface was 3.12%, the track width change rate was 26.6%, the profile deviation of gear surface was 5.64 μm, and the micropitting surface is 75.12%. The experimental results of alkyl phosphite ester were superior to those of phosphorodithioate and aryl phosphate ester and had better resistance to micropitting corrosion performance. The results of MPR tester and FZG testing machine for oil micropitting corrosion resistance test had a good correspondence.

CHARACTERISTICS OF ALKYATES OIL AND ENTERPRISE STANDARD

Gao Bingmei

2020, 51(1):  55-61. 

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The properties of 19 kinds of alkylates produced by different processes were tracked and analyzed, the results indicated that alkylates had high octane number, zero aromatics, low levels of olefin, and oxygen. It is important for plants to focus on the influence factors of alkylates, including octane number; initial distillation point, saturated vapor pressure, level of sulfur and olefin, because these factors affect the performance of blended gasoline. A typical alkylate was selected as a blending component for China VI gasoline. The performance of blended gasoline was verified. On the basis of these data, a first-class enterprises standard of alkylation oil -Isooctane component- (Q/SH PRD 0753-2019), was formulated. The procurement, production and sales units of alkylates can be benchmarked to ensure that the quality of alkylated oil meets the blending requirements for China VI gasoline.

FAST ANALYSIS METHOD FOR HYDROCARBON COMPOSITION OF FEEDSTOCK AND PRODUCT OF HYDROGENATION UINT IN LTAG PROCESS BY MID INFRARED SPECTROSCOPY

2020, 51(1):  62-67. 

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To adjust the reaction conditions of LTAG process, it is necessary to monitor the hydrocarbon compositions of feedstock LCO and products of hydrotreating unit. In this work, MIR calibration model was established by using the mid-infrared spectra data of a large number of LCO and hydrotreated diesel samples and partial least squares method to analyze rapidly and accurately the hydrocarbon compositions of LCO feedstock and products of hydrotreating unit in LTAG process. The MIR method has good consistency with mass spectrometry results. Compared with near infrared fast analysis method, MIR method performs higher accuracy. The method is simple and repeatable, and meets the needs of field fast analysis.

SPECIATION ANALYSIS OF ORGANIC CHLORIDES BY COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY COUPLED WITH TIME-OF-FLIGHT MASS SPECTROMETRY

2020, 51(1):  68-73. 

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A qualitative and speciation analysis method for organic chlorides was developed basing on comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry, and the method was applied to investigate the molecular form and distribution of organic chlorides in different atmospheric distillates from high-chlorine crude oils. Analysis results showed that organic chlorides in atmospheric petroleum distillates were mainly in forms of (poly-) chloral alkane/olefin, chlorophenol, alkylchlorobenzene, alkylchloroaniline, alkylchloronitrobenzene and their homologues. Moreover, the origin of organic chlorides in crude oil was reviewed and comprehensively analyzed, and some routes for chlorine source were inspected preliminarily by the above-mentioned GC×GC-TOF MS method. The results indicated that in the oilfield viscosity reducer there were lots of organic chlorides such as (poly-) chloral alkane/olefin, chlorhydrin, chlorinated ketone and ether, and organic chlorides in the chosen organic coatings were mainly 1,2,3-trichloropropane and polychloroethers. Consequently, molecular characterization of organic chlorides in petroleum can provide information to trace chlorine sources for developing selective chlorine removal processes, such as adsorption dechlorination, hydrodechlorination, and for designing chlorine adsorbents, chlorine transfer agents and hydrodechlorination catalysts.

STUDY ON FACTORS INFLUENCING THERMAL REACTION OF HIGH ACID NUMBER HEAVY OIL

2020, 51(1):  74-79. 

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The processing volume of high acid number residue oil is gradually increasing, and the problems of high yield of coke and low yield of light oils during processing of high acidic residue oil is attracting more attention. Up to now, there is still lack of clear and consistent understanding about the effects of acidity, asphaltene content and other factors on the thermal behavior of high acidic residue. The effects of carboxylic acid, asphaltene, metal, free radical initiator, coke powder, catalytic slurry on the thermal reaction of representative mixed heavy oil were compared. It was proved that the addition of carboxylic acid, free radical initiators and coke powder into heavy oil promoted the thermal cracking of heavy oil to a certain extent. While asphaltene, metal and the like accelerated the thermal condensation of heavy oil to coke, among which the asphaltene promoted the coke formation more obviously. The results show that the high coke yield of high acidic heavy oil is not caused by the carboxylic acid contained, but by the nature of asphaltene and carbon residue.

RHEOIOGICAL AND SWELLING CHARACTERISTICS OF COAL-OIL SLURRY PREPARED FROM COAL AND INFERIOR OIL

2020, 51(1):  80-85. 

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The adaptability of coal to coal-oil slurry with different inferior oils during the process of coal-oil co-processing was investigated. The swelling degree and apparent viscosity of coal after different swelling time were investigated. The effect of swelling on rheology at pipeline transportation temperature was discussed. The results showed that the coal-oil slurry of the Baishihu coal and the >310℃ heavy oil showed shear thinning behavior; the slurry of vacuum residue and high temperature coal tar revealed non-continuous shear thickening trend; the system with shear thickening trendency were not suitable solvents for preparation of coal-oil slurry. The coal-oil slurry, using heavy oil as solvent, appeared swelling behavior at working temperature (80℃), and the apparent viscosity increased. The swelling behavior of the coal-oil slurry had little effect at a higher temperature (≥90 ℃)on rheological property.

OPERATION PROBLEMS AND TREATMENT MEASURES OF WET PURIFICATION UNIT FOR FCC FLUE GAS

Zhou Jianhua

2020, 51(1):  86-91. 

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The major problems of FCCU flue gas in wet purification process were analyzed and the countermeasures were proposed. The problems included blue smoke tail, ammonia escape of SCR, complex acids and high salt content in scrubbing solution, and visual white smoke from purified flue gas. The sulfur transfer agent to recover SO_x from source was recommended as the main measures. After using the sulfur transfer agent, the SO_x removal rate of the flue gas was 50% to 95%, the blue smoke tail disappeared and the ammonia escape of SCR was reduced by using automatic precise control technology of ammonia injection. Temperature should be considered for pH control of the scrubbing tower. It is necessary to consider the recovery of particulate matter from the source to reduce the wet recovery

SOURCE PROFILES AND TRACING OF VOLATILE ORGANIC COMPOUNDS IN REFINERIES

2020, 51(1):  92-96. 

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Refineries have made a great contribution to volatile organic compounds (VOCs) emission. It is of great significance to study the technologies for VOCs source profiles measuring and source tracing for refineries to control pollution. This paper summarizes the research status of VOCs emission characteristics, emphatically introduces the research progress of VOCs source profiles and source tracing technology in refineries and existing problems. A set of perfect source tracing analysis technology is established by improved sampling and analysis methods and using mathematical algorithm, the source profiles based on production process as well as an optimized source tracing model to provide theoretical and technical support for traceability of atmospheric pollutants in refineries. This technology will effectively realize the integrated monitoring of safety and environment control for refineries.

FACTORS AFFECTING NO_x CONCENTRATION IN FCC FLUE GAS AND CONTROL METHODS

2020, 51(1):  97-100. 

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After the start-up of the fourth cycle of the 2.8 Mt/a heavy oil catalytic cracking unit of SINOPEC Hainan Refining & Chemical Co. Ltd. in 2018, the NO_x concentration in flue gas was close to the emission limit of 200 mg/m³ and became a bottleneck restricting the processing load of the unit. In this paper，based on the transformation mechanism of nitrogen in FCC coke, the properties of feedstock，the operations of regenerator and waste heat boiler were analyzed to find the influence factors. Finally，the feed control，operating conditions and additives were determined to control the NO_x concentration of the flue gas.

DEEP PURIFICATION OF EXHAUST GAS IN REFINING CATALYST PRODUCTION PROCESSN UNIT

2020, 51(1):  101-104. 

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In the production of refinery catalysts, the exhaust gas often contains pollutants such as dust and nitrogen oxides. It is necessary to use appropriate technology to clean the exhaust gas and meet the more strict emission requirements. Through the comparison of dust removal and denitration technologies, the combination of cloud-dedusting technology and low temperature oxidative denitration technology is used to deeply remove dust and nitrogen oxides from the tail gas in the production process and reduce their concentrations to 20 mg/m3 and 100 mg/m3, respectively, and meet the special emission limit requirements of the "Petrochemical Industry Pollutant Emission Standards" (GB 31571-2015).

RESEARCH ON MODELING OF DELAYED COKING ADIABATIC REACTION PROCESS BASED ON STRUCTURE-ORIENTED LUMPING

2020, 51(1):  105-113. 

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Based on the structure-oriented lumping method (SOL), 21 structural units including hydrocarbon structure and hetero atom structure were designed, and the structural vector of 2 791 kinds of typical molecules representing 55 kinds of delayed coking raw material molecules was constructed. Based on the mechanism of delayed coking reaction, The 38 reaction rules of 10 kinds of reactions, including carbon chain cleavage, dehydrogenation, ring opening, diene synthesis, H2S removal, CO2 and CO removal, as well as hydrodenitrogenation, were developed and used to describe the entire delayed coking reaction network. Based on the corresponding reaction rate constants and reaction heat data, a set of differential equations for reaction kinetics was established. The improved Runge-Kutta method was used to solve equations, building a kinetic model of delayed coking adiabatic reaction based on structure-oriented lumping to predict the typical molecular compositions and product distributions of delayed coking process. The prediction accuracy of the established kinetic model is better than that of the isothermal reactor model without considering the reaction thermal effect. Using the model of lumped adiabatic reactor guided by delayed coking structure to simulate the process of delayed coking reaction under different coking reaction temperature and cycle ratio, the prediction errors of gas, gasoline, diesel, wax oil and coke yields were less than 1.7 percentage points and the prediction errors of typical molecule content in products did not exceed 2.0 percentage points.

OPERATION PARAMETER OPTIMIZATION OF COMPLEX DISTILLATION SYSTEM BASED ON KRIGING SURROGATE

2020, 51(1):  114-120. 

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Optimizing the operation parameters of atmospheric and vacuum distillation units can effectively improve the economic benefits of refineries，but it would be time-consuming if the optimization process was iteratively conducted with their rigorous mechanism model. In order to reduce the computational cost，Kriging surrogate-based intelligent method is proposed to optimize the operation parameters of an atmospheric distillation system in this paper. In detail，Kriging meta-modeling technology is adopted to construct the relationship model between some key operation parameters and output variables for the distillation process，and then the relationship model is used to represent the MESH equations of the complex distillation system. Moreover，employing particle swarm optimization (PSO) algorithm in the design space to conduct global intelligent search of operation parameters. The proposed method can not only ensure the global optimization of the operation parameters，but also greatly reduce the computing time when solving the problems. Simulation results, using Aspen HYSYS, shows the effectiveness and superiority of our method and confirms its obvious engineering practicability.