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Table of Content

    12 February 2013, Volume 44 Issue 2
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    THE VALENCE STATE OF VANADIUM AND ITS POISONOUS EFFECT ON CATALYSTS DURING CATALYTIC CRACKING PROCESS
    2013, 44(2):  1-7. 
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    A review concerning the valence state of vanadium on catalysts during catalytic cracking process, factors affecting the variation of vanadium valence states, poisoning effect on catalysts caused by various vanadium oxides and mechanism of poisoning, as well as research methods, characterization tools and essential results, is presented. It can be concluded that the negative effect on the structure and performance of FCC catalysts by high valence state of vanadium species is much more serious than that of by low valence state vanadium species.
    EFFECT OF WATER-CHLORINE IMBALANCE ON THE PERFORMANCE OF CCR CATALYST
    2013, 44(2):  8-13. 
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    Water-chlorine balance of the system is very important for reforming catalyst to maintain good performance. The changes of physical-chemical properties and catalytic performance of CCR catalyst during commercial operation were studied. The deactivation of catalyst by water-chlorine imbalance and reactivation of said catalyst were investigated. Results show that the long-term imbalance of water-chlorine during operation leads to the decrease of chlorine content in catalyst, resulting in the severe agglomeration of Pt particles which reduce the activity and selectivity of catalyst significantly. The test results of a reforming catalyst collected from a CCR unit after running 1 967 d show that the maximum diameter of its Pt particle reaches 90 nm, as compared with fresh catalyst, its aromatics content in C5+ product is 12.89 percentage point lower, aromatics yield drops 10.59 percentage point and coke yield increases 0.77 percentage point. However, the redispersion of large Pt agglomerate is rather difficult under conventional oxychlorination and reduction conditions, especially under the operation conditions of CCR unit.
    REACTIVE PERFORMANCE AND COMMERCIAL APPLICATION OF FHUDS-5 CATALYST TO PRODUCE ULTRA LOW SULFUR DIESEL
    2013, 44(2):  14-17. 
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    Aiming at meeting the demands of diesel quality upgrading, a new generation of FHUDS-5 catalyst for ultra deep HDS was developed by Fushun Research Institute of Petroleum and Petrochemicals based on modified alumina carrier developed newly, optimizing the combination of active metals and improving metal impregnation technology. The results of pilot plant tests showed that compared with FH-UDS, FHUDS-3 and other catalysts, FHUDS-5 catalyst possessed high relative HDS and HDN activities, to achieve the same HDS result its reactive temperature was lower more than 10 ℃. Meanwhile, FHUDS-5 catalyst demonstrated good stability and feed adaptability. The commercial application results on low pressure diesel hydrotreating units indicated that FHUDS-5 catalyst exhibited excellent HDS activity, clean diesel fuels meeting the emission standards of National Ⅲ, Ⅳ and Euro V could be produced with said catalyst.
    PREPARATION OF Ti-HMS MOLECULAR SIEVES AND STUDY ON THEIR CATALYTIC OXIDATIVE DESULFURIZATION PREFORMANCE
    2013, 44(2):  18-21. 
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    Ti-HMS mesoporous molecular sieves were prepared at ambient temperature by using neutral dodecylamine (DDA) as template and tetraethyl orthosilicate (TEOS) as silicon source, the n(SiO2)/n(TiO2) of which were 20, 40, 80 and 160. These samples were characterized by XRD, FT-IR, SEM and the catalytic performance of Ti-HMS was evaluated by using catalytic oxidation of thiophene as probe reaction. The influences of n(SiO2)/n(TiO2),reaction time and reaction temperature on the catalytic performance of these samples were studied. Results showed that the prepared samples had typical HMS mesoporous structure, and with spherical particle size of 0.2-0.4 μm. Under the same reaction conditions, Ti-HMS molecular sieve having n(SiO2)/n(TiO2) of 20 exhibited the highest sulfur removal rate; the sulfur removal rate of Ti-HMS having n(SiO2)/n(TiO2) of 160 was higher than those of samples with n(SiO2)/n(TiO2) of 40 and 80, which indicated that the catalytic activity of Ti-HMS molecular sieve was depended on its Ti content and pore size. Under the testing conditions, with the prolonging of reaction time and the increase of reaction temperature, the sulfur removal rate increased.
    RESEARCH ON OXIDATIVE STABILITY OF BIODIESEL AND DETERMINATION OF APPARENT ACTIVATION ENERGY OF OXIDATION REACTION
    2013, 44(2):  22-26. 
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    The distributions of fatty acid methyl esters in several biodiesel fuels prior and post to accelerated oxidation were determined by EN14103 standard method, and the results showed that the contents of linoleic acid methyl ester and linolenic acid methyl ester in biodiesel were the key factors affecting the oxidative stability of biodiesel. The oxidation of biodiesel was further studied through determining the apparent activation energy of biodiesel oxidation. Results showed that the apparent activation energies of oxidation reactions for biodiesel fuels having various oxidative stabilities were varied; adding antioxidant into biodiesel could increase the apparent activation energy of oxidation reactions significantly, as a result, the oxidation of biodiesel was postponed and its oxidative stability improved.
    STUDY ON THE PROMOTERS FOR Na2CO3-γ-Al2O3 SORBENT TO ENHANCE THE ADSORPTION OF SO2 AND NO
    2013, 44(2):  27-32. 
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    Various transition metal oxide promoters were added respectively into Na2CO3-γ-Al2O3 sorbent for removing SO2 and NO from flue gas. The effect of promoters on the adsorption performance of sorbent was studied by a fixed-bed reactor, and the influence of adsorption conditions on the performance of modified sorbent was investigated. Results showed that MnO2-modified Na2CO3-γ-Al2O3 exhibited the best adsorption performance due to enhancing the surface lattice oxygen concentration of the sorbent, which could promote the oxidation of SO2 and NO and increase the adsorption capacity of sorbent. The optimum adsorption conditions for Mn-Na2CO3-γ-Al2O3 were as follows: SO2/NO molar ratio of 2, the adsorption temperature in the range of room temperature to 50 ℃ and oxygen volume fraction of over 2.0%.
    INFLUENC OF FEEDSTOCKS ON THE YIELDS AND PROPERTIES OF HYDROTREATED RESIDUAL OIL
    2013, 44(2):  33-36. 
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    Influence of feedstock property on the yields and properties of residual oil formed during residue hydrotreating were studied by autoclave, using four residue feeds from different sources under the same reaction conditions. The experimental results demonstrated that feedstocks with higher viscosity and asphaltene content, no matter atmospheric residue (AR) or vacuum residue (VR), exhibited higher conversions, higher yields of gasoline, diesel and coke, as well as lower residual (>350℃) yields. Compared with feedstock, in residual formed by hydrotreating, its saturate content increased while aromatic content decreased. In all the four feedstocks tested, only for Fushun VR having extreme low asphaltene content, in its residual formed by hydrotreating the sum of asphaltene plus coke yield was higher than the asphaltene content in feedstock, which indicated that during hydrotreating reactions, for feedstocks with relative high asphaltene content, the asphaltene species mainly hydrocracked to smaller molecules.
    RESEARCH ON KINETIC MODEL FOR CATALYTIC CRACKING OF VACUUM GAS OIL USING STRUCTURE ORIENTED LUMP METHOD
    2013, 44(2):  37-42. 
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    Structure oriented lumping was applied to construct a catalytic cracking kinetic model of vacuum gas oil (VGO) on molecular level. 686 kinds of single-core molecules were selected to form a matrix of VGO feedstock and non-linear least squares method was used to obtain the percentage of individual molecule. 60 reaction rules were proposed to build a complex reaction network including more than 40 000 times of reactions. To reduce the number of variable parameters, rate constants were calculated by 5 segments. The reaction network was solved by matrix transformation instead of Runge-Kutta method and product distributions could be obtained. Experimental data were collected from catalytic cracking of mixed Middle East VGO performed on a XTL-6 type of riser reactor for model verification. Comparison results showed that the calculated values of product distributions agreed well with the experimental data, the relative errors were less than 10%. Besides, this model exhibited well adaptability with the changing of reaction temperature and catalyst to oil ratio.
    HYDROTREATING OF FEEDSTOCK CONTAINING DAO AND CGO OVER RN-32V CATALYST
    2013, 44(2):  43-46. 
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    The commercial application of RN-32V catalyst in the 2.3 Mt/a hydrotreating unit of Fujian Refining and Petrochemical Company was introduced processing feedstock containing deasphalted oil (DAO) and coker gas oil (CGO), which was high in asphaltene, carbon residue and metal contents, as well as with high FBP. The assessment of performance at the initial stage showed that using RN-32V catalyst, under the process conditions of a hydrogen partial pressure of 14.04 MPa, an average catalyst bed temperature of 384.6 ℃ and LHSV of 1.11 h-1, the sulfur and nitrogen contents of the treated feed dropped significantly, which improved the feed quality for FCC unit.
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    AN ANALYSIS OF COMBINED OPERATION OF FEEDSTOCK HYDROTREATING AND DEEP CATALYTIC CRACKING
    2013, 44(2):  47-50. 
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    The operation of gas oil hydrotreating unit and deep catalytic cracking (DCC) unit of SINOPEC Anqing Branch is introduced and the influence of hydrotreated feedstock on the operation of DCC unit is analyzed. Results show that the hydrotreated mixed gas oil can be used as a high quality feedstock for DCC unit. The product distributions of DCC unit is improved remarkably: light oil yield increases by 2.89 percentage point, and the yields of dry gas, coke and low value products decrease significantly. Meanwhile, the quality of products is improved greatly as well, items including sulfur content, induction period, olefins content and aromatics content of DCC gasoline can meet the specifications of gasoline for national emission standard III.
    TECHNICAL REVAMPING OF A RFCC UNIT FOR CLEAN GASOLINE PRODUCTION
    2013, 44(2):  51-56. 
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    For clean gasoline production, a 1.5 Mt/a RFCC unit was successively revamped by ARFCC technology and MIP-CGP technology to reduce the olefin content of gasoline. The revamping, operation, product slate and property, as well as energy consumption of these two technologies were reviewed in this paper. It was found that compared with base case, both technologies could meet the demand of producing clean gasoline, yet MIP-CGP technology exhibited more technical advantages. Adopting MIP-CGP technology, the capacity of the unit expanded to 1.7 Mt/a, the residue blending ratio could be in the range of 15%—53%, and the quality of gasoline was improved significantly. When residue blending ratio was below 35%, the olefins volume fraction of gasoline could be kept below 32%, RON maintained over 90 and the gasoline induction period was prolonged remarkably. Besides, the energy consumption of the unit with MIP-CGP technology was lower than the other cases.
    THE INFLUENCE OF FLEXI-COKING TECHNOLOGY ON REFINERY PLANNING AND DESIGNING
    2013, 44(2):  57-60. 
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    The configuration comparison of a new 13 million tons per year refinery is selected as a case study. Flexi-coking technology is introduced and supposed to replace the combined process of delayed coking plus partial oxidization for hydrogen production, so total flow chart, utility engineering, costs of investment and operation might change accordingly. Likewise, the influence of flexi-coking technology on new refinery planning and designing is analyzed and summarized briefly. On the whole, flexi-coking technology is wide adaptable to residue feeds, and also it can generate low heat value fuel gas to make up the shortage of fuel for refinery, however, since no domestic existing unit is running, it is always hard for refinery to make decision without hesitation.
    CAUSES OF ABNORMAL CATALYST FLUIDIZATION IN RFCC REGENERATOR AND COUNTERMEASURES
    2013, 44(2):  61-65. 
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    Causes of abnormal catalyst fluidization in the regeneration system of RFCC unit at Hainan Petrochemical Company were analyzed based on operation experiences and basic theory of solid particles fluidization. It was found that lower catalyst bulk density, overload of unit and partial interrupted of semi-regeneration slope pipe were the main causes. Countermeasures were proposed and put into practice, such as optimizing catalyst formula and production technique to improve fresh catalyst bulk density and shape; increase the bulk density of regenerated catalyst by using some magnetic separated catalyst; reducing unit load and properly adjusting the main air flow ratio between the 1st and 2nd regenerators, as well as optimizing the pressure differential between reactor and regenerator; adjusting the number of aerating sites and aerating air flow to improve catalyst transfer in slope pipe. Since then, the abnormal fluidization of catalyst in the regeneration system was eliminated.
    STUDY ON THE SYNTHESIS AND PERFORMANCE OF LIQUID BENZOTRIAZOLE ALIPHATIC AMINE DERIVATIVE
    2013, 44(2):  66-69. 
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    A kind of liquid benzotriazole derivative was synthesized by the reaction of benzotriazole and an aliphatic amine in sodium hydroxide solution. Tests including four ball machine, copper strip corrosion, PDSC, rotating bomb oxidation and so on were carried out to study its performance of antiwear, anticorrosion and antioxidation, as well as solubility with lube base oil, especially under low temperature. The results indicate that the performance of this prepared liquid benzotriazole derivative is equal to that of the commercial solid benzotriazole derivative T406, and its low temperature solubility in lube base oil is improved significantly, thus, it can be blended with base oil better and used more conveniently compared with T406 additive.
    RESEARCH ON DEFOAMING PERFORMANCE OF DIFFERENT DEFOAMERS APPLIED IN DELAYED COKING PROCESS
    2013, 44(2):  70-73. 
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    An evaluation method for testing the defoaming performance of defoamers at high temperature was introduced, and it was used to compare defoamers for delayed coking process. The thermal stability of defoamers was investigated by TGA. Test results showed that the silicon-free defoamers were very unstable at high temperature, they decomposed at about 150℃ and lost defoaming function, thus they were not suitable for delayed coking process. Defoamers having organic silicon maintained good defoaming performance at temperature as high as 400℃, it was suggested that the proper dosage of these defoamers for delayed coking should be in the range of 20—50 ?g/g. Moreover, defoamer with crosslinking structure of polysiloxane exhibited good defoaming effect even at low dosage.
    RESEARCH ON THE CHARACTERISTIC PARAMETER FOR ASSESSING THE ANTI-WEAR PROPERTY OF LUBRICANTS UNDER VARIABLE SPEED AND LOAD CONDITIONS
    2013, 44(2):  74-76. 
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    A four-ball tester is used to evaluate the anti-wear property of lube oil under variable load and speed conditions, and a concept of anti-wear characteristic parameter R is proposed through analyzing parameters (load P and speed V) which cause the mutation of friction coefficient. The characteristic parameter R is related with the product of P×V at the mutation of friction coefficient for testing oil and reference oil, i.e. R is defined as the ratio of testing oil P×V to that of reference oil. Test results show that by introducing parameter R and using R to update PB and PD value, it is helpful to distinguish the difference in antiwear performance of lube oils from the same type.
    COMPREHENSIVE MONITORING AND ASSESSMENT OF ODOUR EMISSION SOURCES FROM REFINERY Ⅱ. CLASSIFICATION OF ODOROUS SOURCES AND EMISSION ASSESSMENT
    2013, 44(2):  77-83. 
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    Offensive odour emissions from various storage tanks, wastewater treatment facilities and oxidative sweetening units of a typical refinery were monitored and evaluated comprehensively. The concentration of odorous gases, the emissions of total hydrocarbons, benzene homologues (BTEX) and odour were estimated. Results show that for the above mentioned odorous sources, pollutants in the emissions including NMHC, benzene, toluene, xylene, hydrogen sulfide, methyl mercaptan, ethyl mercaptan and dimethyl disulfide are over standard somewhat, and the over standard of concentration is more serious than that of emission rate. In this paper, odour pollutants and odour emission sources are classified into three classes based on their odour emission rates respectively. For odorous pollutants, class A is hydrogen sulfide, which occupies 67.9% of the total odour emissions; class B consists of methyl mercaptan, ethyl mercaptan and isopropyl mercaptan, dimethyl disulfide, methyl ethyl disulfide and diethyl disulfide, which takes 31.8%; class C is mainly BTEX, which only takes a 0.3%. For odour emission sources, sour water tanks are ascribed to class A, their emissions occupy 57.1% of the total odour emissions; wastewater treatment facilities, high temperature wax oil tanks and heavy waste oil tanks are belonged to class B and takes a share of 37.3%; alkaline sludge tanks, coke quenching water tanks, intermediate tanks and oxidative sweetening units are zoned to class C, their emissions take 5.6%. The emissions of total hydrocarbons from the main odour emission sources are 261 kg/h, in which the emissions from wastewater treatment facilities, sour water tanks and oxidative sweetening units account for two-thirds. The emissions of BTEX from the main odour emission sources are 23.8 kg/h, in which the emissions from wastewater treatment facilities and coke quenching water tanks account for two-thirds.
    OPTIMIZATION OF WASTEWATER TREATMENT SYSTEM IN YUMEN REFINERY
    2013, 44(2):  84-87. 
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    Due to the effluent from wastewater treatment system of Yumen Refinery could not meet the emission standard steadily, some countermeasures were adopted, such as revamping the regulating pool, building north sewage lifting pool, enhancing the removal rate of floating oil, applying pressurized dissolved air floatation, using new anaerobic biological treatment, combining peristaltic bed and BAF treating technology and setting up a new sludge treatment system. Since then, the quality of total discharge water is improved greatly with hydrocarbons of 0.71 mg/L, COD of 54.0 mg/L, BOD5 of 29.7 mg/L, sulfide of 0.02 mg/L, suspended solids of 14.67 mg/L, cyanide of 0.04 mg/L, ammonia-nitrogen of 0.48 mg/L, volatile phenol of 0.27 mg/L and pH value of 7.37, which well meet the requirements of national emission standard (GB8978-1996) and it also provides the feasibility of recycling discharge water.
    DIRECT DETERMINATION OF ARSENIC CONTENTS IN CRUDE OILS AND HEAVY OILS BY GF-AAS
    2013, 44(2):  88-93. 
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    By selecting modifiers and optimizing various experimental conditions, a direct determination method of arsenic contents in crude oils and heavy oils by graphite furnace atomic absorption spectrometry (GF-AAS) is established. The linear range of this method is arsenic mass fraction in the range of 16—3 000 μg/kg with detection limit of about 5.4 μg/kg, the relative standard deviations of reproducibility tests are less than 10% and recovery rates of standard addition are more than 90%. In conclusion, this method has the advantages of fast determination, high sensitivity and easy to be operated, which can well meet the demand of routine analysis.
    DETERMINATION OF METHYL ANILINE COMPOUNDS IN GASOLINE BY GC-MS
    2013, 44(2):  94-98. 
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    A gas chromatography-mass spectrometric (GC-MS) method was developed for the determination of methyl aniline compounds (including N-methyl aniline, p-methyl aniline, o-methyl aniline, m-methyl aniline, N,N-dimethyl aniline) in gasoline. The methyl aniline compounds were liquid-liquid extracted with acid and separated by capillary chromatographic column, the qualitative measurements were conducted with selected ion monitoring mode(m/z=107, 120)and then quantified with external standard method. The concentration of extractant in sample pretreatment and the type of capillary column used were optimized. It is concluded that using hydrochloric acid solution with volume fraction of 10% as extractant, separating by DB-1MS (30 m×0.25 mm×0.25 μm) capillary column, with methyl aniline compounds concentration in the range of 100—300 mg/L, the recoveries of standard addition are in the range of 85%—103%. The relative standard deviations of reproducibility tests are not more than 2.5% and the detection limit is 1.0 mg/L when SNR (signal to noise ratio) is established as 3. This method is accurate, with good reproducibility and low detection limit.