PETROLEUM PROCESSING AND PETROCHEMICALS

THE THEORETICAL BASIS OF OIL-COAL CO-PROCESSING AND PROCESS OPTIMIZATION

Jun Long

2011, 42(6): 1-5. doi:

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This paper first described known thermal decomposition and hydrocracking processes using heavy oil and coal as feedstock respectively, where the characteristic and structural difference between crude and coal were presented. Studies showed that though fundamental differences observed between heavy oil and coal based thermal decomposition processes, the principle of free radical chain reactions was shared, which was the theoretical basis of oil-coal co-processing. It was reported that aromatics up to three-ring was mostly found in the hydrocracked products from coal feed; whereas segments from long paraffinic chain or aliphatic substituents in polycyclic aromatic hydrocarbons were the major components of oil based hydrocracked products. It should be noted that asphaltene and gum in heavy oil could favor the formation of coke and lower light oil yield during oil-coal co-processing, and the selection of suitable coal species was also significant. Based on the discussions, a two-stage reactors design was proposed for the co-processing process.

STUDY ON THE TRANSFORMATION OF DIBENZOTHIOPHENE IN FCC PROCESS

2011, 42(6): 6-10. doi:

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The transformation mechanism of dibenzothiophene (DBT) in FCC process was studied on a fixed fluidized bed unit in laboratory using DBT containing hexadecane as feed. Test results showed that under the conditions of a reaction temperature of 500 ℃, a catalyst to oil mass ratio of 6 and a space velocity of 10 h-1, the conversion of DBT was about 45%. Alkylation reactions were the main reactions in which DBT took place. The main product was methtyl-benzothiophene and followed by C2~C5 alkyl-DBT. Nearly 90 percentage of the sulfur in the DBT-hexadecane reaction system was distributed in the liquid products, only a small portion was converted to H2S and coke. The presence of DBT reduced the conversion of hexadecane, the yield of gasoline fractions decreased, the yields of dry gas, diesel fractions and coke increased.

THE THERMODYNAMICS AND DYNAMICS FOR THE ADSORPTION REMOVAL OF TETRACHLOROETHANE

Xiangmiao Zhao

2011, 42(6): 11-16. doi:

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The thermodynamic and kinetic characteristics of adsorbing tetrachloroethane on adsorbent M were studied via static adsorption experiments. The experimental results show that the adsorption isotherm of adsorbing tetrachloroethane on adsorbent M is a typical L type adsorption curve, and this adsorption process agrees well with the Langmuir adsorption equation. The thermodynamic parameters illustrate that the absorption of tetrachloroethane on adsorbent M could happen spontaneously, it is an exothermic process attributed to physical adsorption. The dynamics of adsorbing tetrachloroethane on adsorbent M could be described by pseudo-second order kinetic equation. With the increase of adsorption temperature, the initial adsorption rate and adsorption rate constant exhibit an increase tendency.

SYNTHESIS AND CHARACTERIZATION OF EU-1/ZSM-5 COMPOSITE ZEOLITE

Yanping

2011, 42(6): 17-22. doi:

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EU-1/ZSM-5 composite zeolite was synthesized with organic template (TPABr and TPAOH) and EU-1 zeolite was used as aluminum source. As-synthesized sample was characterized by XRD, FT-IR and SEM-EDS. XRD results showed that EU-1 and ZSM-5 were coexisted in the composite zeolite；its pattern was similar with that of the mechanical mixture of EU-1 and ZSM-5. FT-IR spectra showed that characteristic absorption bands of the composite zeolite shifted to higher wavenumber, compared with the mechanical mixture of EU-1 and ZSM-5. N2 absorption and desorption isotherms of the sample showed that secondary mesoporous structure was observed in the composite zeolite. From the SEM images it can be seen that in composite zeolite tiny grains of nano-ZSM-5 crystal grew on the edges of EU-1 zeolite particles. EU-1/ZSM-5 composite zeolite with high crystallinity can be synthesized under the following conditions: m(EU-1)/m(SiO2)=1.1~1.4，n(OH-)/n (SiO2)=0.07~0.15，n(TPAOH)/n(TPABr)=1:9~5:5，crystallization temperature of 100～120 ℃ and crystallization time of 24~72 h.

A DEVELOPMENT OF RTS TECHNOLOGY FOR ULTRA-DEEP HYDRODESULFURIZATION OF DIESEL FUEL

Shi Ding,Hong Nie

2011, 42(6): 23-28. doi:

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By analyzing the key factors influencing ultra-deep desulfurization of diesel fuel, a process for ultra-deep hydrodesulfurization of diesel (RTS) was developed. Studies on the process of RTS technology for producing ultra-low sulfur diesel fuels were carried out on a pilot plant unit. Results showed that by optimizing process flow and operation conditions, using feedstocks mainly containing high sulfur straight-run diesel, ultra-low sulfur diesel fuels with sulfur contents less than 50 μg/g and 10 μg/g could be obtained under high space velocity (50% higher than that of conventional hydroprocessing). Stability test results showed that RTS technology could well meet the needs of long-term operation in industrial unit.

INDUSTRIAL APPLIACTION AND OPERATION ANALYSIS OF RHSS TECHNOLOGY FOR JET FUEL SWEETING

2011, 42(6): 29-33. doi:

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The industrial application of simple RHSS technology applied in jet fuel sweeting unit of Qingdao Refining and Chemical Company was introduced. The complex unit combined with diesel hydrofining unit had the advantages of simple operation, low cost, low energy consumption. The problems of unit were analyzed, countermeasures were also proposed，This technology has good prospect in product jet fuel.

FCC PROCESS DEVELOPMENT BASED ON LOW TEMPERATURE CONTACT AND HIGH CATALYST/OIL RATIO OPERATION

MENG Fan-dong

2011, 42(6): 34-39. doi:

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The feasible executions of FCC processes based on the technical idea of "low temperature contact and high catalyst/oil ratio operation" were analyzed systematically. These processes could be categorized into two groups according to the material and/or energy exchange modes between system and surrounding. Various case studies following this idea were discussed and some positive results showed that the heavy oil crackability was enhanced, product slates were improved and clean fuels were produced cleanly.

DEVELOPMENT AND PERFORMANCE EVALUATION OF A COMPLEX DENITROGENATION AGENT FOR COKER GAS OIL

MA Shou-Tao

2011, 42(6): 40-44. doi:

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Using Daqing coker gas oil as feedstock, a complex denitrogenation agent was developed and the effect of reaction temperature and reaction time on the removal of nitrogen in coker gas oil was investigated to obtain the optimal denitrogenation conditions. Under the optimal conditions of a denitrogenation agent to oil volume ratio of 1:150, a reaction temperature of 80 ℃ and a reaction time of 30 min, compared with feed the treated oil exhibited lower contents of basic nitrogen and aromatic hydrocarbon, cetane number increased by 0.5 units and the treated oil yield was 99.2%. A comparative evaluation was carried out using coker gas oil and treated oil as feedstock respectively, with the same hydrofining catalyst and process conditions: a reaction temperature of 360℃, a reaction pressure of 6.0 MPa, a LHSV of 1.5 h-1 and H2/oil volume ratio of 800. The evaluation results showed that with similar hydrofined oil yields the properties of the hydrofined oil using denitrogenation agent treated oil as feed was better: the contents of nitrogen, sulfur and aromatics was lower 31.5 μg/g, 17.1 μg/g and 6.9%, respectively; cetane number was increased by 7.7 units.

INDUSTRIAL APPLICATION OF SFT418 CATALYST FOR FISCHER-TROPSCH SYNTHESIS

xiuzhang wu,yulin shi

2011, 42(6): 45-49. doi:

Asbtract ( 1995 )

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A proprietary catalyst for slurry Fischer-Tropsch (F-T) synthesis was developed by China Shenhua Coal to Liquid and Chemical Company and it was applied firstly in a newly built indirect coal liquefaction unit with a capacity of producing 180 thousand tons oil per year. The whole operation was successful and qualified light oil, heavy oil, heavy wax and synthetic water were produced. The transfer of activated catalyst from pretreatment unit to F-T synthesis unit and the online substitution of fresh catalyst for deactivated catalyst were conducted successfully. During the second run, the plant kept stable operation for 1 113 h continuously, and the results showed that the performance of SFT418 catalyst could well meet the demands of industrial operation: the space-time yield of C5+ reached 1.0 t/t cat·h, CO2 selectivity was less than 20 mol%, CH4 selectivity was in the range of 1.5-3.5 mol% and the iron content of refined heavy wax was less than 5 ?g/g.

EFFECT OF CALCINATION TEMPERATURE ON NiMoS HYDROCRACKING CATALYST CONTAINING SULFUR PRECURSORS

2011, 42(6): 50-56. doi:

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NiMoS hydrocracking catalysts containing sulfur precursors calcined under various temperatures were prepared by kneading method, using ammonium tetrathiomolybdate and nickel nitrate as active components, and composite support composed of γ-Al2O3 and modified zeolite Y. The properties of catalysts were investigated by FT-IR, XRD and TEM. Test results indicated that with the increase of calcination temperature, the total acidity of the catalysts with sulfur precursors increased firstly and then decreased; more medium strong acid amount and higher B/L value were observed for these catalysts as compared with the oxidation state catalyst. The interactions between metal component and support in the catalysts containing ammonium tetrathiomolybdate as sulfur precursor were weakened, thus suitable crystal sizes and stacking numbers of active metal components could be obtained and the catalytic performances of the catalysts were improved. However, exceeded high calcination temperature was not in favor of forming suitable average crystal size and stacking number of MoS2 active phase. Catalyst with sulfur precursors calcined at 500 ℃ exhibited good hydrocracking performance: high conversion and liquid yield, as well as high selectivity and outstanding isomerization performance.

DEVELOPMENT OF DIJ CATALYST FOR DIESEL FUEL HYDROISODEWAXING

WEN Guang-Ming

2011, 42(6): 56-59. doi:

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DIJ hydroisodewaxing catalyst for diesel fuel was developed using zeolite-alumina support and W-Ni active components. The physical-chemical properties of the catalyst were characterized by XRD, FT-IR and BET techniques. The activity and stability of the catalyst were evaluated on a hydrogenation unit combined with a hydrofining catalyst, using Daqing coker gas oil and the mixture of coker gas oil/FCC LCO as feed respectively. Results showed that the yield of diesel fuel was more than 89.0% with sulfur content less than 50.0 ?g/g, its freezing point was lowered more than 14 ℃ and the loss of cetane number was less than 0.6 units, which indicated that DIJ catalyst possessed good activity and stability.

CATALYTIC SYNTHESIS OF DIISOPENTYL OXALATE OVER MESOPOROUS S2O82?/SnO2 SOLID SUPERACID

2011, 42(6): 60-65. doi:

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A novel mesoporous S2O82?/SnO2 solid superacid catalyst was prepared using SnCl4o5H2O and polyethylene glycol 6000 as organic template. The prepared catalyst was characterized by XRD，TGA-DTA and N2-adsorption. The catalytic activity of S2O82?/SnO2 solid superacid for the esterification of oxalic acid and isoamyl alcohol was studied, and the effect of catalyst calcination temperature, acid/alcohol molar ratio, catalyst dosage and reaction time on the esterification rate was investigated as well. Results indicate that the mesoporous S2O82?/SnO2 solid superacid catalyst possess tetragonal crystalline structure, and the existence of S2O82? tends to delay the crystallization of SnO2 and inhibits the growing of crystal, thus the catalyst exhibits good catalytic activity for diisopentyl oxalate synthesis. Under the conditions of a catalyst calcination temperature of 500 ℃, n(isoamyl alcohol):n(oxalic acid)=3:1, a toluene adding amount of 30 mL, m(catalyst):m(oxalic acid)=7.5 and a reaction time of 2.5 h, the yield of diisopentyl oxalate reached 99.2%. The obtained diisopentyl oxalate was used as cetane enhancing agent and added into the FCC diesel fractions from the No.1 Refinery of CNPC Fushun Petrochemical Company, it was found that the cetane number of this diesel fuel increased 1.2~3.0 units, and without significant effect on its other properties.

STUDY ON THE PREPARATION OF NANOPARTICULATE CeO2 AND ITS FUNCTION AS ADDITIVE TO IMPROVE FUEL CONSUMPTION AND EMISSION OF DIESEL ENGINE

2011, 42(6): 66-72. doi:

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Nanoparticulate CeO2 well dispersed in diesel fuel was prepared from oil-soluble salicylaldimine Schiff Base-cerium (III) chloride complexes under higee conditions. The effect of using nano-CeO2 dispersed component as fuel additive on the diesel engine performance and emissions were evaluated on Phaser140Ti-E30 test device with inline four-engine. A fuel saving of about 7% was obtained and the waste emissions including exhaust smoke, total hydrocarbons (THC) and particulate matter (PM) reduced with a nano-CeO2 adding dosage of 50 g/g in diesel fuel.

SIMULATION STUDY OF 1,2,4-TRIMETHYLBENZEN SEPARATION PROCESS WITH MULTI-EFFECT HEAT INTEGRATION DISTILLATION

2011, 42(6): 73-76. doi:

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The simulation study of separating 1,2,4-trimethylbenzene from C9 aromatics was carried out using chemical flowsheet simulation software Aspen Plus and selecting PR-BM equation as thermodynamic model. Through comparing and analyzing the simulation results of various separation processes, it can be seen that using double-effect heat integration distillation technology can significantly reduce the energy consumption of distillation process. The energy saving rate can reach 64.79 %，the product purity and yield are 98.51 % and 90.54 %, respectively.

SIMULATION STUDY OF ENERGY-SAVING IN THE PROCESS OF SEPARATING INDUSTRIAL n-HEXANE FROM HYDROGENATED RAFFINATE OIL

Jin Xue-KUN,MA Feng-yun

2011, 42(6): 77-83. doi:

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The rectification process with double tower for separating industrial grade n-hexane from hydrogenated raffinate oil was simulated by selecting BK10 model in Aspen Plus software. Firstly, the production process under full load was simulated, and the results are compared with the practical operation data. The relative errors of these two were less than 5%, which verified the parameters selected were reasonable, such as HETP, the column efficiency and model. Secondly, the optimized process conditions were obtained by analyzing the effect of operation pressure, reflux temperature, feed position and the heat conditions of feed on the process energy consumption, and then countermeasures for revamping were proposed. Finally, according to the characteristics of the system, an energy-saving program with backward-feed double-effect distillation and heat-integration was proposed. The hydraulic calculation results confirmed the technical feasibility of this program, and the process simulation results show that adopting this proposal, a 53.1% reduction in operation cost might be obtained, i.e. a cost saving of 3.009 Million RMB annually.

AN ANALYSIS OF IMPURITIES AFFECTING THE VOLATILE BASE CONTENT IN CAPROLACTAM

bin sun

2011, 42(6): 84-87. doi:

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The compositions of impurities in the concentrated mother liquids after the recrystallizations of three various quality grades caprolactam products were analyzed by GC-MS to compare the impurities that affect the volatile base contents in these products. Results showed that the impurities were mainly composed of C3-C7 amides with straight chain, C6 imides, oximes and aniline, in which C3-C7 amides with straight chain and C6 imides had significant effect on the volatile base content: with the increase of 0.1 mmol/kg these impurities, the volatile base content could increase 0.1 mmol/kg. Aniline had less effect on the volatile base content; oximes and lactams had little effect. As compared with the superior caprolactam product, in the qualified product impurities were mainly composed of C3-C7 amides with straight chain and C6 imides, in the first-class product minor impurities were n-valeramide and n-caproamide, however, the existence of these impurities in products leads to a higher volatile base content, which degrades the product class.

DETERMINATION OF N-METHYLDIETHANOLAMINE IN REFINERY DESULFURIZED LIQUID BY ION-EXCHANGE CHROMATOGRAPHY WITH NON-SUPPRESSED CONDUCTIVITY DETECTION

2011, 42(6): 88-92. doi:

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A new method was developed for the separation and determination of N-methyldiethanolamine (MDEA) in the desulfurized liquid from refinery by ion-exchange chromatography with non-suppressed conductivity detection using nitric acid as mobile phase. The pretreated sample was passed through a weak acidic cation-exchange analytical column leaching with 7 mmol/L nitric acid at a speed of 1.0 mL/min, rapid separation was achieved and the peaks were well distinguished without significant interference from the others. The detection limit of MDEA was found to be as low as 0.638 3 mg/L. The relative standard deviations were 1.03 % (n = 8, measuring peak area) and 0.94 % (n=8, measuring retention time). Linear calibration curve in the range corresponding to 5.00-500 mg/L was obtained for MDEA. Determinations of rich liquor and barren liquor containing MDEA from refining process were carried out and the recovery (n=3) of MDEA was found to be in the range of 99.1 % ~100.3 % with relative standard deviations less than 3%.

PROCESS SIMULATION AND ANALYSIS OF ABSORPTION-STABILIZATION SYSTEM

zhang jinxian

2011, 42(6): 93-98. doi:

Asbtract ( 1996 )

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Simulations of absorption-stabilization systems were conducted to study the methods for decreasing the content of C3 and C4 in dry gas. Taking a typical absorption-stabilization system of a domestic delayed coking unit as case study, the simulation strategies including the selection of unit model, the determination of thermodynamic methods and etc. were discussed. The main factors affecting the separation effect were analyzed and finally, an operation scheme to improve the separation efficiency of absorption-stabilization process was proposed. Results showed that RKS equation is a suitable thermodynamic model for absorption-stabilization system, its simulation results are in good agreement with the data from commercial performance test. With the increase of inlet feed temperature of desorption tower, and decreasing the flow rate of absorbent for stabilized gasoline, the energy consumption of the system could be reduced, yet the absorption effect might be reduced as well. Attention should be paid to the bottom temperature of the desorption tower since it might effect the compositions and flow rate of LPG, as well as the C3 and C4 content in dry gas. There is an idea LPG reflux ratio for stabilizer, in order to obtain improved absorption effect the operating reflux ratio should be less than the idea value.

STUDY ON THE CORROSION INHIBITION BEHAVIOURS OF CATIONIC ASPHALT EMULSIFIERS

2011, 42(6): 99-102. doi:

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The corrosion inhibition behaviours of 10 cationic asphalt emulsifiers were studied by static weight loss test and simulating the corrosion system of emulsifying asphalt and paving. Results showed that some types of cationic asphalt emulsifiers including imidazoline, alkyl amines, alkyl amides and quaternary ammonium, exhibited excellent corrosion inhibition performance in hydrochloric acid corrosion system, possessing both emulsification and corrosion inhibition functions. Scanning electron microscopy was also used to study the corrosion inhibition behaviours of cationic asphalt emulsifiers and the inhibition mechanism was discussed. It was suggested that the adsorption of emulsifiers on the metal surface might form an adsorption film to prevent the contact of metal with the corrosion medium, thus the corrosion was inhibited.

DEGRADATION OF REFINING WASTEWATER CONTAINING PHENOL WITH SUPER OXIDATION METHOD

2011, 42(6): 103-107. doi:

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In this paper refining wastewater containing phenol was disposed by photo/Fenton/ C2O42- system, the reaction mechanism was discussed and a kinetic equation was set up. The experimental results indicated that photo/Fenton/ C2O42- technology could enhance the removal of phenol by Fenton reagent effectively. When treating 250 mL of wastewater containing 500 mg/L phenol under the conditions of a H2O2 (30%) dosage of 0.5 mL，a Na2C2O4 (1 g/L) dosage of 10 mL, a FeSO4·7H2O dosage of 0.05 g, a pH value of 3, a reaction temperature of 40℃ and a reaction time of 30 min, the phenol removal rate reached more than 98%. And the experimental results indicated that the oxidizing reaction of wastewater containing phenol by Photo/Fenton/C2O42- technology was a first order reaction.

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