Table of Content

    30 March 2013, Volume 15 Issue 1
    catalyst research
    The Content of This Issue
    2013, 15(1):  0-0. 
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    Catalyst Research
    Alumina Supported Vanadium Oxide Catalysts for Residue Hydrotreating
    2013, 15(1):  1-9. 
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    In order to evaluate the role of vanadium in the hydrogenation (HYD), a series of alumina-supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman, 51V NMR, XPS, as well as TPR. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmosphere residue) was measured after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfurs in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM of the residue, but have slight effect on HDS.
    Commercial Applications of RAX-2000A and RAX-3000 Paraxylene Adsorbents
    2013, 15(1):  10-13. 
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    RAX series paraxylene (PX) adsorbents are developed by the Sinopec research institute of petroleum processing (RIPP) and manufactured by Sinopec catalyst company. So far, RIPP has launched two brands of PX adsorbents: RAX-2000A and RAX-3000. In 2004, RAX-2000A PX adsorbent was first commercially applied in the Parex unit at Sinopec petrochemical company. Performance test showed that the average purity of the PX product reached 99.81%, with an average yield of 98.6% per pass. RAX-3000 is a new generation of PX adsorbents, which maintains most advantages of RAX-2000A, but also has higher selective adsorption capacity, increased by at least 8%. The actual unit production capacity of RAX-3000 adsorbent was increased by about 18%. RAX series PX adsorbents came up to the level of the same category of PX adsorbents world-widely. Moreover, they exhibited good adaptability to unfavorable feedstock containing high ethyl benzene (EB) fraction and better mechanical strength. Recently, an industrial demonstration unit for PX production by SMB developed by Sinopec has been built in a local petrochemical company, adopting RAX-3000 as PX adsorbent. Preliminary results indicated that compared with RAX-2000A, the A/Fa and D/F were notably decreased due to the higher selective adsorption capacity.
    Development and Application of DCC Catalysts to Meet New Demand
    2013, 15(1):  14-18. 
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    The new generation of DCC catalysts, DMMC/RMMC series developed by RIPP are introduced. The large molecule cracking ability is enhanced by increasing the portion of large pores; coke selectivity is improved by adjusting the acidity site density of matrix surface; selective cracking reactions are increased, and the sphericity of catalysts is improved by adopting new preparation method. The commercial results shown DMMC/RMMC series catalyst increase the propylene yields respectively by 2.43w%,0.8w% and 1.3w% for mixed VGO, VGO plus AR,and hydrotreated VGO feed compared to the previous catalysts while some of other product yields were improved. The enterprises made more profits after using new DCC catalysts.
    Solid Acid Used as Highly Efficient Catalyst for Esterification of Free Fatty Acids with Alcohols
    2013, 15(1):  19-24. 
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    A novel solid acid catalyst, which was prepared from sodium alginate (SA) and metal chlorides and characterized with XRD and FT-IR spectrometry, was used for the preparation of biodiesel via esterification reaction. The study results showed that the aluminum-alginate complex prepared in a cheap and easy way exhibited high catalytic activity, and a 92.6% conversion of methyl oleate was obtained in the presence of 4 m% of catalyst dosage upon refluxing for 3 h of methanol and acid mixed in a molar ratio of 10:1. It should be noted that the catalyst can be applied to the esterification reaction of fatty acids with various carbon chain length on methanol or different short chain alcohols, indicating that the catalyst is suitable for the preparation of biodiesel from waste oils with a high acid value.
    Preparation of alumina binder-added PtSnNa/AlSBA-15 catalyst for propane dehydrogenation
    2013, 15(1):  25-31. 
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    The present article compares propane dehydrogenation performances of alumina binder-added PtSnNa/AlSBA-15 catalysts prepared via three different procedures with the performance of a PtSnNa/AlSBA-15 catalyst without binder. All these catalysts have been investigated by reaction tests and some physicochemical characterizations such as BET, H2 chemisorption, catalytic grain intensity, NH3-TPD and TPO. Results showed that the addition of alumina binder can enhance the mechanical strength of catalyst evidently. Moreover, different preparation procedures not only modified the characteristics of both acid and metal function but also affected the coke deposition on the catalysts. Among these catalysts studied, the catalyst prepared by impregnation followed by the agglomeration of alumina binder, exhibited the highest catalytic activity and stability compared with others undergoing different preparation procedures. The possible reason may attribute to the highest metallic dispersion and the strong interactions among Pt,Sn and the support.
    Scientific Research
    Hydrocarbon composition of different VGO feedstocks and the correlation with FCC product distribution
    2013, 15(1):  32-39. 
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    Three different types of VGO were selected and cut into various distillates by true boiling-point distillation (TBD), and the distillates were further separated into different components (saturates, aromatics and resins) by solid phase extraction (SPE). Hydrocarbon compositions of saturates and aromatics were characterized on quasi-molecular level by GC/MS and GC/TOF. Cracking reactions of VGO, the distillates, hydrocarbon components (saturates and aromatics) were performed on an ACE (model AP) unit. 9 correlation parameters (mainly based on the previous assumption of basic structure units, BSU) which could better reflect hydrocarbon structures and compositions were put forward from the quasi-molecular level analysis data, and correlated with FCC product distribution by multi-regression method. A series of correlation formulas were obtained. The formulas were further verified by comparing experimental and calculated FCC yields of two other VGO feedstocks.
    Flammability and Explosion Property of Gases in the Process of Propane Oxidation to Acrylic Acid in One Step
    2013, 15(1):  40-48. 
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    Acrylic acid is widely used in industries of different scopes. One of the production methods of it is propane oxidation to acrylic acid in one step. In order to study the flammability and explosion property of gases during the process, explosion limits and safety oxygen content of gases in circulating compressor outlet, reactor entrance and exit were theoretically calculated and experimentally tested. Finally, inert limit were also tested. It showed that gases in circulating compressor outlet and reactor exit were nonflammable in three aspects: explosion limits, safety oxygen content and inert limit. C3H6 and O2 were higher in reactor entrance, which made the mixed gases easy be ignited. But the large amount of inert gases suppressed explosion effectively. As a conclusion, no explosion phenomenon will happen in all the three sections. But gases in reactor entrance are most dangerous, where more supervision on the content and concentration of gases and more control on the temperature and pressure should be taken. Besides this, open flame, hot surfaces and other sources of ignition are forbidden in working spaces. The experimental results can be used for similar oxidation process of propane.
    Purification of Crude Glycerol from Waste Cooking Oil Based Biodiesel Production by Orthogonal Test Method
    2013, 15(1):  48-53. 
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    Purification of original crude glycerol from by-product of biodiesel was conducted on a laboratory scale by using the combined chemical and physical treatments based upon repeated cycles of acidification to the desired pH of 5 using 85% H3 PO4 at 70℃ for 60 min, allowing phase separation and harvesting of the glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, the complex reaction of the harvested glycerol phase occurred by adding 0.03 %( w/w) of sodium oxalate at 80℃ for 30min with the impurity removal rate of 19.8%. The fraction between 164 and 200℃ was collected by vacuum distillation followed by decolorization with 2% of active carbon at 80℃ twice at an acceptable purity of 98.10% (w/w) glycerol.
    Et3NHCl-AlCl3 Ionic Liquids as Catalyst for Alkylation of Toluene with 2-Chloro-2-methylpropane
    2013, 15(1):  54-60. 
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    Alkylation of toluene with 2-Chloro-2-methylpropane (t-Bu-Cl) to synthesize p-tert-Butyltoluene (PTBT) was performed, which was catalyzed by triethylamine hydrochloride aluminum chloride ionic liquids. Different kinds of ionic liquids were prepared with Et3NHCl and AlCl3, and the effect of the molar ratio between AlCl3 and Et3NHCl, reaction time, reaction temperature, ionic liquid dosage, as well as the molar ratio of toluene to Chloro-2-methylpropane on the alkylation reaction of toluene with Chloro-2-methyl- propane was investigated. The optimal reaction conditions were detected to catalyze the reaction with high conversion of (t-Bu-Cl) and good selectivity for PTBT. Furthermore, the reusability and regeneration of the catalyst were explored.
    Oxidation Desulfurization of Model Sulfur Compound by Potassium Ferrate in the Presence of the Catalyst of Phosphomolybdic Acid
    2013, 15(1):  61-65. 
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    In this work, removal of thiophene from model Oil have been studied by using adsorption, extraction and oxidation/absorption methods, respectively. In Adsorption desulfurization process, utilizing different commercial adsorbents to eliminate thiophene at ambient pressure and mild temperature, the result shows that carbon powder has the best adsorption ability. In extraction desulfurization process, the best desulfurization result is obtained when DMF is used. In oxidation/adsorption desulfurization procedure, taking synthetic potassium ferrate as the oxidant, phosphomolybdic acid aqueous solution as catalyst, thiophene was oxidized and removed from hydrocarbons by a combination process of active carbon adsorption, the residual sulfur content of model oil could be reduced to 15.3 mg?L-1 from 200 mg?L-1, the desulfurization rate reached to 92.3%.
    Modeling and Simulation
    Selecting suitable heat source in refinery for Multi-effect distillation based on grey system theory
    2013, 15(1):  66-72. 
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    The higher cost of driving heat source is the shortage of multi-effect distillation (MED) to deal with high salinity wastewater in refinery, so it is an important significance to evaluate and select heat source for MED. In this paper, the MED was obtained from a typical refinery located in northwest of China, and the heat sources also were from that refinery. At the same time, a new evaluation methodology to evaluate heat source for selecting suitable heat source for MED based on grey system theory is proposed. The five units including 18 fluids in refinery were established as evaluation projects, and three factors including safety effects, operating costs, the difficulty degree of the energy recovery were defined as evaluation indexes, the values of which were established by analysis. By the grey correlation analysis, the result is that the grey correlation degrees of the units was 0.554(AVDU), 0.767 (FCCU1#), 0.608(FCCU2#), 0.544 (DCU1#), 0.617 DCU2#), respectively. Thus, the optimal heat source was from FCCU1#. Further analysis the fluids from FCCU1#, the grey correlation degrees of the fluids was 0.855(Oil and Gas in top of tower), 0.914 (Oil and Gas Cycle), and 0.482 (Diesel), respectively. Thus, the optimal heat source was Oil and Gas Cycle.
    Feasibility of an Intermediate Fluid Vaporizer with Spiral Wounded Tubes
    2013, 15(1):  73-77. 
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    A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube heat exchangers at high pressure with the advantage of compact space of heat exchangers. Thermal analysis on the two processes of forced convection and vaporization type heat transfer in the spiral wound tubes and vapor condensation /re-boiling type of heat transfer via intermediate fluid in shell side shows the feasibility of this promising technology.
    A Novel Modeling, Simulation and Optimization Approach of Crude Oil Cold Stripping Process
    2013, 15(1):  78-84. 
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    Cold stripping is the most common process for crude oil sweetening in oilfields particularly at offshore installations because of its low price and relatively easy operate conditions in compare with other sweetening processes. In this paper cold stripping process in tray column has been modeled mathematically in static and dynamic modes, solved with MATLAB software and then existing treatment facilities of an offshore oil production complex in Persian Gulf has been used for verifying the model results. With help of HYSYS software the effective parameters on the process have been discussed and optimized condition after some plant modifications for improving the performance of stripper columns has been proposed.
    catalyst research
    Degradation of wastewater containing nitrobenzene with O3 and H2O2 by high gravity technology
    2013, 15(1):  85-94. 
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    Nitrobenzene industrial wastewater was degraded by high gravity technology with O3 and H2O2. Effect of high gravity factor, H2O2 concentration, pH value, liquid flow-rate, reaction time on the removal efficiency of nitrobenzene were investigated. The experimental results show that the high gravity technology enhances the ozone utilizing efficiency and O3/ H2O2 have coordinate effects. The degradation efficiency of the COD removal rate and nitrobenzene removal rate separately reached 45.8% and 50.4% when the high gravity factor is 66.54, pH value is 9, molar ratio of H2O2 and O3 are 1:1, liquid flow rate is 140L/h, ozone concentration is 40mg/L, multiple dosing mode of H2O2 is 6mL/h, and the reaction time is 4h. Compared with the conventional stirred mixers, the COD removal rate and nitrobenzene removal rate of nitrobenzene wastewater separately increased from 22.9% and 23.3%