Table of Content

12 November 2017, Volume 48 Issue 11

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EFFECT OF PHOSPHORUS MODIFIED BETA ZEOLITE ON ISOBUTYLENE YIELD IN FCC PROCESSING

2017, 48(11):  1-6. 

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The pore structure, aluminum distribution and acid properties of Beta zeolite were adjusted by the dealumination with organic acid and subsequent the phosphoric acid modification. The modified Beta zeolite was characterized to investigate its physicochemical properties, hydrothermal stability and the catalytic performance for producing isobutylene. The results showed that after modification, the hydrothermal stability of modified Beta zeolite is improved and the channel is more open due to removal of non-framework aluminum. The ratio of Bronsted acid to Lewis acid is increased. The microactivity of modified Beta zeolite aged under the conditions of 800℃，17h，and 100% steam is close to that of USY zeolite due to increased hydrothermal stability. The addition of additives containing modified Beta zeolite into FCC catalyst significantly increases the FCC isobutylene yield. The commercial results proved that adding the additives increases the LPG yield by 2.68%, in which the yields of propylene and isobutylene increase by 1.01% and 0.54%, respectively.

STUDY OF CONVERSION MECHANISM OF METHYLCYCLOPENTANE OVER MODIFIED Pt-Sn REFORMING CATALYST SYSTEM

2017, 48(11):  7-11. 

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Using methylcyclopentane thatis most difficult to convert in five membered ring hydrocarbonas a model compound, the conversion situation of methylcyclopentane was investigated over the addition of alkali metal potassium and rare earth metal and reaction temperature. The results Indicated that under the Pt-Sn reforming catalysthigh temperature (≥510 ℃) benefit the conversion improvement of methylcyclopentane, while the selectivity of Heterogeneous dehydrogenation products—benzene was little affectedwithin the experimental temperature range and the process conditions of high temperature and lower liquid hourly space velocity can improve pyrolysis product’s selectivity; The addition of alkali metal K in moderation resulted that the acidity of catalysts reduced, cracking reaction weakened, liquid yield increased, methylcyclopentane’s conversion dropped, and the selectivity of benzene was not affected; The addition of bi-Rare earth metal made that cracking reaction weakened, liquid yield increased, benzene selectivity was slightly increased (510 ℃) in lower LHSV, conversion of methylcyclopentane and benzene selectivity obviously fell in higher LHSV.

EFFECTS OF PHOSPHORUS MODIFICATION ON ACIDITY OF Pt/HZSM-5 CATALYST AND ITS HYDROISOMERIZATION PERFORMANCE

2017, 48(11):  12-17. 

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The Pt-P/HZSM-5 isomerization catalysts were prepared by incipient wetness impregnation and characterized by N2 adsorption-desorption, XRD, NH3-TPD, and Py-IR. The isomerization performance of the prepared catalysts was evaluated in a continuous fixed bed reactor. The results showed that the addition of a small amount of phosphorus can significantly change the acid amount and acid strength distribution of Pt/HZSM-5. The strong acid sites decrease and the weak acid and Br?nsted acid sites increase. Pt-P/HZSM-5 catalysts significantly inhibit the cracking reaction and improve the isomerization rate and dimethylbutane selectivity. At 1.5 MPa, 280 ℃ and H2/oil volume ratio of 500, LHSV of 1 h-1, the Pt-P/HZSM-5 catalyst with 1% P and 0.4% Pt gives the best isomerization results of 75.78% n-hexane conversion rate, 75.36% isomerization rate, 3.69% cracking rate and 6.65% dimethylbutane selectivity.

COMMERCIAL APPLICATION OF FH-40B CATALYST FOR JET FUEL HYDROGENATION

2017, 48(11):  18-22. 

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FH-40B catalyst developed by SINOPEC Fushun Research Institute of Petroleum and Petrochemicals was commercially used in a 1.4 Mt/a jet fuel hydrogenation unit of a petrochemical refinery. The calibration results showed that the qualified No.3 jet fuel (in compliant with GB 26537—2006) can be produced from the feed with 0.14% μg/g sulfur. The jet fuel produced is characterized by the mass fraction of mercaptan sulfur of 3μg/g, smoking point of 24.5 mm, freezing point of -57.2℃ and the volume fraction of naphthalenes of 0.36% at reaction conditions of 265 ℃,1.75 MPa, hydrogen/oil volume ratio of 100 and LHSV of 2.95 h－1. The commercial results demonstrated that the catalyst FH-40B has a good activity and stability, the catalyst deactivation rate is 0.021 ℃/d, the pressure drop of the catalyst bed is smooth, which is favor of long-running for the unit.

INDUSTRIAL APPLICATION OF NAPHTHA PRE-HYDROFINING CATALYST LY-2010

2017, 48(11):  23-27. 

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A pre-hydrofining catalyst LY-2010 for catalytic reforming feed was developed by Petrochemical Research Institute of CNPC and evaluated using SR naphtha from Lanzhou Petrochemical Company in a 360ml hydrogenation reactor. The results were compared with that of a domestic reference catalyst. The results showed that the hydrogenation performance of LY-2010 is better than that of the reference catalyst though the inlet temperature of LY-2010 is 10℃lower. The catalyst was successfully applied in the 1.4 Mt/a CCR unit of Liaoyang Petrochemical Company. Both sulfur and nitrogen content of the hydrofined product are less than 0.5 μg/g under reaction conditions of 274 ℃, 2.2 MPa and LHSV of 5.0 h-1，in compliance with the demand of reformer feed.

INFLUENCE OF ZEOLITE TYPE ON HYDROCRACKING REACTION OF TETRALIN

2017, 48(11):  28-34. 

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Ni-Mo catalysts with modified Beta,Y, ZSM-5 zeolites as carriers were prepared by equal volume impregnation method and named as CAT-B, CAT-Y and CAT Z, respectively. The catalysts were characterized by XRD, BET, NH3-TPD, Py-FTIR and H2-TPR techniques. The influence of different zeolite catalysts on activity and product selectivity for tetralin hydrocracking were investigated on a fixed bed continuous hydrogenation device. The results showed that CAT-B catalyst has a specific pore structure and surface area and higher L acid and B acid content than CAT-Y and CAT-Z catalysts. The weaker interaction between the carrier and active metals of CAT-B is beneficial to the dispersion of the metals. The order of conversion rate for tetralin hydrocracking is CAT-B> CAT-Y> CAT-Z. Moreover, the CAT-B catalyst has the highest selectivity to BTX and cracking products and the lowest selectivity to the condensation products at the same conversion rate of tetralin.

APPLICATION OF TAIL GAS HYDROGENATION CATALYST C-234 IN HIGH H2S CONTENT NATURAL GAS PURIFICATION

2017, 48(11):  35-38. 

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The use of C-234 hydrogenation catalyst from Criterion Co. to purify natural gas for 8 years in Sinopec Puguang natural gas clean plant was introduced. On the basis of the long-term operation results, the technological measures to stabilize the operation of the catalyst are summarized, where include stabilizing the operation of sulfur recovery unit, controlling the air rate of the heating furnace and the inlet temperature of the tail gas hydrogenation reactor.

HYDROGENATION UNIT REVAMPING TO PRODUCE CHINA V COMPLIANT DIESEL AND OPERATION ANALYSIS

2017, 48(11):  39-45. 

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Considering the status of hydrofining feedstock distribution and the diesel production, the No. 4 diesel hydrofining unit with 3.0 Mt/a capacity of Gaoqiao Co. was revamped to produce the national V compliant diesel fuel. The calibration results at full-load operation (285t/h) after revamping indicated that The calibration results at full capacity (285 t/h) showed that the refined diesel only has sulfur content less than 8μg/g using a feed consisting of 56.14% straight-run diesel, 35.09% coker gasoline and diesel, 8.77% FCC LCO, under the reaction conditions of 6.51 MPa in high pressure separator, LHSV 1.05 h-1, gas to oil volume ratio 540 at the reactor inlet, 315 ℃ inlet temperature of R1101 reactor with average bed temperature 353 ℃, inlet temperature of the 2nd reactor (R1102) 346 ℃, average bed temperature of R1102 348 ℃. The cetane number was raised by 7.7, up to 51.9. Each performance index can reaches the China Ⅴ diesel standard.

INDUSTRIAL APPLICATION OF LTAG TECHNOLOGY AT RFCC UNIT

2017, 48(11):  46-49. 

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As demand for diesel continues to slump, the reduction of LCO becomes the major concern for oil refineries. LTAG（LCO To Aromatics and Gasoline）is the technology developed by RIPP to convert LCO into high octane gasoline or light aromatics, where the technical parameters of hydrogenation and catalytic cracking are comprehensive considered and optimized to maximize the production of high octane gasoline. To use LTAG technology, the 2.0Mt/a RFCC unit of Yansan refinery was revamped, and the original lubricating oil hydrogenation device was used as LCO hydrotreating unit. As a result, the gasoline yield is increased from 43.2% to 51.8%, the yield of diesel oil is decreased from 20.5% to 5.9%, the LPG yield is increased from 17.5% to 21.5%, the yields of dry gas and slurry are increased by 0.9 and 1.5 percentage points, respectively, while the coke make is lowered by 0.4 percentage points. The benzene content in gasoline is raised from 1.00% to 1.65%, the aromatics mass content is increased to 38.36% from 34.11%. The RON is increased by 2 units. The adoption of LTAG greatly reduces the amount of LCO output for the refinery.

INDUSTRIAL APPLICATION OF CATALYTIC DISTILLATION-DEEP ETHERIFICATION TECHNOLOGY FOR LIGHT GASOLINE

2017, 48(11):  50-55. 

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The application of the first set of FCC light gasoline etherification device with capacity of 500kt/a in CNPC Guangxi Petrochemical Company was introduced, which adopted an independent catalytic distillation module technology. The results showed that the C5= conversion in the etherification reactor reaches to 73.37%, higher than the design guarantee value 60%. The total C5= conversion of the whole unit is up to 93.42%, close to the design guarantee value 93%. The C6= conversion is 65.65%. The RON of the etherified light gasoline increases by 2.6 units with a decrease of olefin from 68.2% (v) to 29.2% (v). The saturation vapor pressure of the light gasoline is reduced by 35.3 kPa, indicating that the etherification process is conducive to improve the proportion of high-grade gasoline. The 60 kt/a methanol can be converted into gasoline component and the economic benefit is remarkable.

HYDROCRACKING WAX OIL BLENDING WITH HYDROTREATED DIESEL

2017, 48(11):  56-59. 

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In view of the current domestic diesel market, hydrocracking wax oil with hydrotreated diesel was commercially practiced to broaden the range of raw materials, make full use of the capacity, improve the operation efficiency and reduce the comprehensive energy consumption of the hydrocracking unit. The commercial results showed that the hydrotreated diesel is converted into high value-added products such as heavy naphtha and aviation kerosene, which can greatly improve the economic benefit of the unit.

FEASIBILITY OF REDUCING CYCLE RATIO OF DELAYED COKING CYCL OIL

2017, 48(11):  60-63. 

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Under the consistent conditions of the outlet temperature of heating furnace, the operating pressure of coking tower and the evaporation zone temperature of fractionator, CNPC Dushanzi refinery reduced the circulation ratio of the unit from 0.4 to 0.13 by technique of partially circulating oil. The measures increase the wax oil by 9.44 percentage points and the total liquid yield by 2.96 percentage points, the yield of diesel, gasoline and coke is decreased by 3.37, 2.38 and 1.98 percentage points, respectively while the energy consumption is lowered by 221.95 MJ/t.

INDUSTRIAL TEST OF DESALTING AND DECALCIFICATION OF FENGCHENG SUPER HEAVY OIL FOR DELAYED COKING

2017, 48(11):  64-67. 

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The Fengcheng super heavy oil with high viscosity and density was processed by diluting and reducing viscosity in 1.5Mt/a delayed coking unit. At the same time, the decalcification industrial test for Fengcheng super heavy oil was conducted by using KR-1 decalcifying agent. The results showed that the viscosity of the heavy oil is reduced to 60.03mm2/s when adding 20% dilute oil, while the contents of water and salt are decreased significantly. The calcium content is reduced from 359μg/g in feed to about 125-275μg/g in product under the moderate decalcification conditions. The current of each stage of the 3 stage desalination device is 150~180, 140~180 and 160~210A, respectively, indicating a small overall fluctuation of current of the unit. The coke ash is below 1.2% with a minimum of 0.7% during the industrial test.

APPLICATION OF SIMILARITY CALCULATION METHOD IN IDENTIFICATION OF SPILLED GASOLINE

2017, 48(11):  68-75. 

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Similarity algorithm was used for the gasoline oil spill identification. The chromatogram information was first converted to a two-dimensional vector, and the similarity between two-dimensional vectors was then calculated by the angle cosine method, by which the similarity of oil spill fingerprint chromatograms can be measured. The extracted oils referring as E-1, E-2 from two gasoline+water samples (C-1, C-2) from different FCC units were used as simulated oil spills. The results showed that the similarity between E-1 and C-1、E-1 and C-2 is 0.996，0.974 respectively, The similarity between E-2 and C-1、E-2 and C-2 is 0.983, 0.992 respectively. It is clear that the similarities difference between extracted oils and its corresponding original gasoline (E-1 and C-1, E-2 and C-2) can clearly distinguish two different gasoline samples. In the case of the repeatability limit method and t test method invalid, the original oil corresponding to extracted oil can be recognized accurately by similarity calculation method.

ACIDITY OF MOLECULAR SIEVE FOR C8 AROMATIC ISOMERIZATION AND REACTION MECHANISM

2017, 48(11):  76-81. 

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The acidity properties of MOR and RIZ zeolites for C8 aromatics isomerization were investigated by the temperature program desorption method. The m-xylene disproportionation / isomerization reactions were used to analyze the catalytic performance of the two zeolites. The desorption activation energies of strong acid sites calculated by NH3-TPD desorption kinetics model is 115.4 kJ/mol and 178.9 kJ/ mol for MOR and RIZ, respectively. RIZ has two types of strong acid sites and 3 times the total amount of strong acid sites than MOR. The results of the m-xylene disproportionation / isomerization reactions at 370℃and atmospheric pressure indicate the higher activity of RIZ than MOR. The disproportionation over RIZ significantly decreases with on-stream time. The initial activity of disproportionation over RIZ is proportional to strong acid amount but is independent of the acid strength.

FLOW FIELD SIMULATION AND VIBRATION ANALYSIS FOR AIR PREHEATER SHELL SIDE

2017, 48(11):  82-88. 

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The air preheater vibration and noise often occurs during operation in a SINOPEC refinery. FLUENT software was used to establish a mathematical model for simulating the flow field of shell side and analyzing the causes of vibration and to propose solutions. The results showed that a kamen vortex exists on the back of the air preheater tube bundle, and there are two large vortices in the bottom cavity. As soon as the vortex frequency is close to the inherent frequency of tube box, vibration and noise occur. The revamping plan was confirmed: increasing clapboard along the direction of the pipes in enamel pipe sectors, adding baffle in the bottom cavity and "well" shaped partition wall in the flue system. After revamping, the vibration and noise no longer occur.

PREPARATION OF ALUMINUM COMPLEX GREASE

qinghua Duan

2017, 48(11):  89-94. 

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The preparation of aluminum complex grease using aluminum isopropoxide as raw material was studied. The effects of the reaction temperature, the reaction sequence of organic acid saponification, the amount of quench oil, the composition of aluminum complex soap and the type of the base oils on the physicochemical properties of the product were investigated. Infrared spectroscopy was used to monitor the synthesis of aluminum complex soap and complex grease. The scale up test was conducted on pilot plant. The materials used are 150BS, where 1/3 is used as quench oil, stearic acid and benzoic acid which react with aluminum isopropoxide at the same time. The optimal reaction conditions are: the molar ratio of stearic acid, benzoic acid and aluminum isopropoxide is 1: 1: 1.2, the maximum refining temperature is controlled at 180-190℃. The preparation process can be well monitored by infrared spectroscopy. The aluminum complex grease prepared has a good performance in mechanical stability, colloidal stability, anti-corrosion and anti-rust, water resistance and abrasion resistance, and meets the US Navy ship grease AA-50433 specification.

CORROSION PREDICTION FOR OIL AND GAS SYSTEM AT TOP OF ATMOSPHERIC PRESSURE TOWER BY ARTIFICIAL NEURAL NETWORK

2017, 48(11):  95-98. 

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Based on the data of low temperature corrosion of atmospheric and vacuum distillation unit, a model was established for predicting corrosion rate of oil and gas system at top of atmospheric tower by artificial neural network. The corrosion factors of pH value, the concentrations of chloride and iron ion as well as sulfide were used as input data and the average corrosion rates as output data. The experimental results showed that the model has good prediction accuracy with a relative error of 10% and average relative error of 7.5%, indicating that the model can reflect the relationship between corrosion factors and corrosion rate predicted.

SIMULTANEOUS DETERMINATION OF LEAD, IRON AND MANGANESE IN GASOLINE BY ENERGY-DISPERSIVE X-RAY FLUORESCENCE SPECTROMETRY

Ke WANG

2017, 48(11):  99-102. 

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AA method for determining elements of lead, iron and manganese in gasoline simultaneously by energy-dispersive X-ray fluorescence spectrometry (EDXRF) was developed. The precision of this method was inspected. The results show a great linear relationship in the ion concentration range from 0μg/g to 100μg/g. The detection limits for lead, iron and manganese are 0.06, 0.4 and 0.09 μg/g, respectively. The recovery rates are between 91.7% and 107.9%, and the relative standard deviation is less than 3%. This method for determination of Pb, Fe, Mn in gasoline simultaneously is more simple and fast.

PROGRESSES OF Cr-BASED CATALYSTS FOR PROPANE DEHYDROGENATION

2017, 48(11):  103-110. 

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Progresses in propane catalytic dehydrogenation and propane oxidation dehydrogenation of Cr-based catalysts were reviewed. The active sites of catalyst，dehydrogenation mechanism and influence factors for the reaction in two processes were introduced. The reasons of catalyst deactivation were analyzed and the influence of regeneration on catalyst performance was discussed. The development of new type catalysts with lower Cr content, higher selectivity and better resistance to coke deposit is the current focus. While the Cr-based catalyst for propane oxidation dehydrogenation with improved propane conversion rate and higher propene yield is the main direction in future.