Oxidative Desulphurization in Hydrogen Peroxide／Formic Acid／Sulfuric Acid System
XIONG Jie -ming,CHI Yao -ling,HU Ying -xi,et al
2009, 22 (3): 1-4. DOI:10.3696/j.issn.1006-396X.2009.03.001
Abstract ( ) PDF ( 310KB ) ( ) 　　
Sulfides in diesel oil can be oxidized and then removed by hydrogen peroxide／organic acid system， and the desulphurization rate depends on the system acidity． Inorganic sulfide acid can esaily adjust the system acidity， and thus
improve the desulphurization rate．Benzothiophene was selected as model sulfide and dissolved in n-octane to form model diesel，hydrogen peroxide / formic acid /sulfuric acid were used as the oxidative system．Experiment has been carried out to investigate the catalytic performance of sulfuric acid and the effect of reaction conditions on the oxidative desulphurization rate．The results show that the desulphurization rate can reach to 95% when the molar ratio of hydrogen peroxide to formic acid to sulfuric acid to benzothiophene is 6.4:2．12:1.50:1;The addition of a small amount of sulfuric acid can raise the system acidity and catalyzes the formation of performic acid．Furthermore，the persulphuric acid with stronger oxidativity produced from sulfuric acid also increases the desulphurization rate,and thus increase the desulphurization rate 10%~29%.The amount of sulfuric acid and formic acid，reaction time and temperature had clear effects on the desulphurization rate．Excessive sulfuric acid would result in too strong acidic system which causes the valid decomposing of hydrogen peroxide and thus the reduction of desulphurization rate，and the suitable molar ratio of sulfuric acid to benzothiophene is from 0.30to 2.10．
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Synthesis of Acetal With Solid Super Acid Catalyst S₂O^2-₈/ZrO₂
WANG Jun-li,MENG Shuang-ming,LI Zhong,et al
2009, 22 (3): 5-8. DOI:10.3696/j.issn.1006-396X.2009.03.002
Abstract ( ) PDF ( 290KB ) ( ) 　　
The S₂O^2-₈/ZrO₂  solid acid catalyst was prepared from ZrOCl₂ and (NH₄)₂S₂O₈ by precipitation, aging, filtering, washing, drying, impregnation and calcination processes. The characterization of the catalyst was performed using XRD, FT-IR and NH₃-TPD. The effect of calcination temperature on the acidic property, textural property and catalytic perfomance of S₂O^2-₈/ZrO₂ solid acid catalysts was studied. XRD patterns show that the catalyst present is higher tetragonal phase. FT-IR spectra shows that S₂O^2-₈ is strongly bind with the ZrO₂ surface bidentately. With S₂O^2-₈/ZrO₂ as catalyst,the effects of molar ratio of glycol to aldehyde, quantity of catalyst, reaction time on the yield of acetalation was more systematically studied and the best reaction conditions were confirmed.  The results show that the molar ratio of butyraldehyde to glycol is 1∶1.4, the quantity of catalyst is equal to 0.25% of feed stocks, the reaction time is 50 min, and the yield of butyraldehyde glycol acetal can reach 75.8%; the yield of benzaldehyde glycol acetal is 68.8% under the following conditions：molar ratio of benzaldehyde to glycol 1∶1.25, the quantity of catalyst 0.5% of feed stocks, the reaction time 50 min.
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Experimental Simulation on Dissociation Behavior of Propane Hydrate by Methanol Glycol Solution Injection
DONG Fu-hai,ZANG Xiao-ya,FAN Shuan-shi,et al
2009, 22 (3): 9-13. DOI:10.3696/j.issn.1006-396X.2009.03.003
Abstract ( ) PDF ( 365KB ) ( ) 　　
The characteristics of propane hydrate dissociation by methanol injection (mass fraction of 30.0％,60.1％,80.2％,99.5％) were investigated using a self-made visual equipment. The results indicate that the liquid temperature decreased slowly and the pressure in the reactors grew linearly when the dissociation reaction began, moreover, the dissociation time decrease with the methanol concentration’s increase,but the degree of decrease became weaker. The average dissociation rates are 0.020 59～0.045 35 mol/(min·L)，and increase linearly with the concentration of methanol solution. Compared with pure water injection, methanol injection reduces dissociation heat of gas hydrate and accelerates gas hydrate dissociation rate. The enhancement of concentration of methanol is benefit to promote dissociation of hydrate.
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Experiments for Hydrate Formation of R141b Emulsions Formed With High Speed Stirring and Ultrasonic
ZHOU Xi-tang,LIANG De-qing,DU Jian-wei
2009, 22 (3): 14-17. DOI:10.3696/j.issn.1006-396X.2009.03.004
Abstract ( ) PDF ( 335KB ) ( ) 　　
In order to solve the problem of refrigerant hydrate formation in a static state ，the Tergitol TMN－6 as emulgator，R141b emulsions were prepared with speed stirring and supersonic respectively，then formed hydrate and decomposed under the condition of program control temperature．The results show that O／W R141b emulsion can be formed with both of the two methods．The two emulsions，at static state，can begin to be formed hydrate within 1.5 h after start of air bath，and finish in 2 h．It is easy for decomposition liquid to be emulsified and to be formed hydrate again．With this method，it can be performed in several hours for a study on hydration mechanism，which provides academic foundation for the application of refrigerant hydrate to cold accumulation air－conditioner．
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Orthogonal Test of Lubricating Oil Biodegradation Accelerated by Lauroyl Glycine
CHEN Bo-shui,FANG Jian-hua,WANG Jiu,SUN Xia
2009, 22 (3): 18-20. DOI:10.3696/j.issn.1006-396X.2009.03.005
Abstract ( ) PDF ( 198KB ) ( ) 　　
Different contents of lauroyl glycine were incorporated into HVI 350 mineral oil and the biodegradabilities of the formulated oils were evaluated on a biodegradation tester. Thereafter, the interaction effect of four factors, i.e. lauroyl glycine content, oil concentration, microbe nutriment composition and oxygen supply, on biodegradation of HVI 350 mineral oil in soil was studied by means of a L9(34) orthogonal test method. The results indicate that lauroyl glycine obviously promotes biodegradation of HVI 350 mineral oil. The biodegradability of HVI 350 oil increases with increasing content of lauroyl glycine while the lauroyl glycine content is smaller than 1.5%. Of the four impact factors, the effect of lauroyl glycine on biodegradation of HVI 350 mineral oil in soil proves to be the most prominent in various biodegradation durations.
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Oxybromination of Phenol Over Phosp horus Molybdenum Tungsten Heteropoly Acid Catalyst Supported on Activated Carbon
GONG Shu-wen, LIU Li-jun, LI Kao-zhen, CUI Qin-xin
2009, 22 (3): 21-23. DOI:10.3696/j.issn.1006-396X.2009.03.006
Abstract ( ) PDF ( 200KB ) ( ) 　　
Activated carbon supported phosphorus molybdenum tungsten heteropoly acid as oxybromination reaction catalyst was prepared via immersion method. Catalyst properties were investigated by X - ray diff raction (XRD) and IR methods. And
the oxybromination reaction activity of catalyst was studied with potassium bromide as bromine source and hydrogen peroxide as oxidizer. The result s indicate that the Keggin st ructure is still retaining af ter supported, and the catalyst exhibit s high oxybromination reaction activity and high selectivity of para product . Supported heteropoly acid slightly lost af ter reaction, but the whole physical phase of catalyst has no significant changes.
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Hydrodenit rogenation Performance of Carbazole for Tungsten Phosp hide Catalyst s Containing Vanadium
LI Cui-qing, SUN Gui-da, LI Feng-yan, ZHANG Deng-qian
2009, 22 (3): 24-27. DOI:10.3696/j.issn.1006-396X.2009.03.007
Abstract ( ) PDF ( 257KB ) ( ) 　　
γ- Al₂O₃ as a support , a series of tungsten phosphide catalyst s containing vanadium were prepared by the method of co - impregnation and temperature programmed reduction ( TPR) in H₂. The catalyst s were characterized by XRD, BET, TG, XPS. Carbazole hydrodenit rogenation ( HDN) activities of catalyst s were tested by a high pressure micro - reactor in condition of 3 MPa , 360 ℃and a space velocity of 4 h^{- 1}. The result show that dispersity of active species WP on the support surface is affected by adding some content of vanadium into tungsten phosphide catalyst. The cooperative effect is greatly between vanadium and support and active species with vanadium content of 5 %, which resulting in a very smaller changing in XRD pattern. Adding some content of vanadium during the preparation of catalyst produced the original phosphiding-reduction temperature of W species on the support surface for catalyst s precursor increasing and phosphiding - reduction extent decreasing, while the amount of high valence of W⁶⁺ on the surface of catalyst s are improved. Catalyst with vanadium content of 1 % is favor to carbazloe HDN reaction, which gaving 12. 7 % higher carbazole HDN conversion than that without vanadium. It is also observed that carbazole HDN reaction showed three paths: a very low direct denit rogenation selectivity (only 3. 2 %, the first path way ) and a high hydrodenit rogenation selectivity ( hydrogenation to saturating one benzene rings followed by denit rogenation, the second path way, and hydrogenation to saturating two benzene rings followed by denit rogenation, the third path way) . The third path way is a primary rout and the HDN selectivity reached 91. 0 %. Compared to the tungsten phosphide catalyst without vanadium , carbazole HDN selectivity of catalyst with 1 % content of vanadium showed a slightly decreased by the first path and gave a 6. 7 % lower by the third path, 7. 3 % higher by the second path.
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The QSPR Research on t he Olfactory Thresholds of Alip hatic Alcohols
DU Xi-hua, CHEN Yan
2009, 22 (3): 28-32. DOI:10.3696/j.issn.1006-396X.2009.03.008
Abstract ( ) PDF ( 198KB ) ( ) 　　
Atomic characteristic value f i of aliphatic alcohols were defined and calculated for QSPR research of aliphatic alcohols, then topological parameter and hydrogen line index H were acquired by the technique of molecule graphics and AM1. QSPR for estimating olfactory thresholds ( POL ) of aliphatic alcohols were achieved based on multiple regression. The regression equations were proposed. The mean error between estimated values and experimental value of 50 aliphatic alcohols is
0. 46 ,while the olfactory thresholds of other 49 aliphatic alcohols molecules were predicted by the regression equation , the mean error is 0. 67. The result s show that the model developed can make a better agreement among estimated values ,predicted values and experimental value.
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Isolation and Characterization of Effective Biosurfactant－Producing Bacteria Lz２－１
WANG Jing, ZHANG Hou-ming, AN Ming-quan, et al
2009, 22 (3): 33-36. DOI:10.3696/j.issn.1006-396X.2009.03.009
Abstract ( ) PDF ( 320KB ) ( ) 　　
A strain Lz2-1 capable of crude oil as main source and energy of producing biosurfactants could be isolated by a series of steps including hydrocarbon enrichment culture and shaking culture and oil displacement activity assay etc. The strain was isolated with the best surface activity in 24 samples from petroleum-contained soil, sludge, waste water etc,and identified as pseudomonas aeruginosa by analysis of 16S rDNA gene and physiochemical methods. The strain produced crude biosurfactant has excellent emulsification property and makes the surface tension of water decrease from 72 mN/m to 28 mN/m. The key components of the crude biosurfactant were extracted and identified as rhamnolipid species by using TLC and FT-IR analyses. The critical micelle concentration of the biosurfactants is 0.630 47 g/L. The present study states that the biosurfactants are major factors of Lz2-1 strain in microbial enhanced oil recovery.
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Purifying Diesel Exhaust Over La_{1 - x} K_xCoO₃ Perovskite - Type Catalyst
ZHU Ling,LIANG Cun-zhen,YU Jun-jie
2009, 22 (3): 37-41. DOI:10.3696/j.issn.1006-396X.2009.03.010
Abstract ( ) PDF ( 343KB ) ( ) 　　
A series of pervoskite - type oxides , La_{1 - x} K_xCoO₃complex catalyst s , with nanomet ric size were synthesized with low temperature through a combustion process. The catalyst s were characterized for crystal st ructure and chemical composition using H₂ - TPR ,XRD ,BET and chemical analysis. The catalytic activities in simultaneous removal of NOx and soot f rom diesel exhaust were evaluated via temperature programmed oxidation ( TPO) equipment , and the effluent s of crystal st ructure and chemical composition on the catalytic activities were also discussed. The result s show that after partial substitution of La ^{3 +} with K⁺ , the st ructure and component of La1 - x KxCoO3 will be changed. When x ≤0. 3 , La_{1 - x} K_xCoO₃is single rhombic perovskite- type phase , the crystal parameters and crystal distances are also increased. And when x ≥0. 4 , Co3O4 is detected in the
samples. La_{1 - x} K_xCoO₃catalyst s have better catalytic activities for simultaneous purification soot and NOx . La0. 7 K0. 3 CoO3 , with the biggest amount s of non - stoichiomet ric oxygen and oxygen vacancy , shows the highest catalytic activities. The ignition temperature for soot combustion on La0. 7 K0. 3CoO3 is dropped to 290 ℃, the conversion ratio of NOx can reach to 53%.
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Effect of Sulfuration Conditions on the Coke － Restraining Activity of Water Solubility Ni Catalyst
LIU Dong,ZHANG Shu-yi,CUI Wen-long,DENG Wen-an,et al
2009, 22 (3): 42-45. DOI:10.3696/j.issn.1006-396X.2009.03.011
Abstract ( ) PDF ( 330KB ) ( ) 　　
The existing state of dispersed Ni catalysts and its precursors for slurry bed hydrocracking of residues were symbolized using microscope，SEM，XRD and LS granularity analyzing apparatus． Then the composition and particle size
distribution of Ni catalysts at different sulfuration time were analyzed，and the coke － restraining activity of the catalyst was also studied．The results show that the structure of nickel sulfide catalyst changed with different sulfuration time，and the coke－restraining activity of the catalyst increased with the prolonged sulfuration time or the increased concentration．While the sulfuration time was longer than 3 h or the concentration of the catalyst was higher than 2000 μg／g ，the coke－restraining activity became steady．
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Composition of Petroleum Sulfonates and the Influence to Interfatial Tension of Oil／Water System
DUAN You-zhi, LI Yang,FAN Wei-yu,LI Shui-ping,et al
2009, 22 (3): 46-50. DOI:10.3696/j.issn.1006-396X.2009.03.012
Abstract ( ) PDF ( 336KB ) ( ) 　　
Active fractions were extracted from series petroleum sulfonates by extraction and back－extraction method，the equivalent weight distribution of them were analyzed by ESI－MS spectrum and the average equivalent weight could be calculated，as well as gas－phase osmotic method was conducted to determine the average relative molecule mass of their oleophylic groups which were obtained by desulfonation．The interfacial tension of oil／water system respectively consisted of series petroleum sulfonates or their active fractions were measured by rotated dropping method．The results show that the difference of the equivalent weight distribution mainly existed in the low and high equivalent weight section，and the one which has properly hydrophile－lipophile balance for the complementation of molecule structure benefiting from broad equivalent molecule weight distribution，its oil／water system can obtain the ultralow interfacial tension．
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Effects of Emulsification Conditions on the Rheological Properties of Heavy Oil－in－Water Emulsions
YANG Fei,LI Chuan-xian, LIN Ming-zhen,GUO Gang
2009, 22 (3): 51-54. DOI:10.3696/j.issn.1006-396X.2009.03.013
Abstract ( ) PDF ( 290KB ) ( ) 　　
The effects of emulsification conditions (including oil/water volume ratio, emulsifier concentration, emulsifying temperature, emulsifying time and stirrer rotation speed) on the rheological properties of heavy oil-in-water emulsions were studied by using polarized-light microscope and control-stress rheometer. The results show that the droplet size and viscosity of heavy oil-in-water emulsions are increased by increasing oil/water volume ratio (1∶9~7∶3); however, when the oil/water volume ratio is high (8∶2), an emulsion inversion (from O/W to W/O) occurs, leading to a sharp increase of emulsion viscosity. With the increase of emulsifier concentration (0.5%~5%), the emulsion droplet size decreases while the emulsion viscosity decreases first, and then increases. When emulsifier concentrations are not reach to 4%, the emulsions are Newtonian fluids; the emulsion changes into non-Newtonian fluid when the emulsifier concentration reaches 5%. The emulsion droplet size and viscosity are decreased by increasing emulsifying temperature (40~70 ℃). When emulsifying temperatures is above 70 ℃, an emulsion inversion occurs due to the invalidation of emulsifier, causing a sharp increase of emulsion viscosity. With the increase of emulsifying time and stirrer rotation speed, the emulsion droplet size decreases while the emulsion viscosity increases. The non-Newtonian characteristics of the emulsions become obvious with increasing emulsifying time and stirrer rotation speed.
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Structure and Catalytic Properties of Dinuclear Copper Complex Encapsulated in SAPO－５
GAO Li-juan,JIAO Shuai-bin,GE Chun-hua,TIAN Yong-hua
2009, 22 (3): 55-59. DOI:10.3696/j.issn.1006-396X.2009.03.014
Abstract ( ) PDF ( 369KB ) ( ) 　　
The dinuclear copper complexe was synthesized and characterized. The macrocyclic copper complexe was immobilized on SAPO-5 molecular sieve, functionalized SAPO-5 molecular sieve by γ-aminopropyl. The sample was characterized by BET, IR and UV-vis spectroscopies, XRD, ICP-AES and TG/DTA techniques,and its structure still remained intact. The catalytic properties of the prepared catalyst were studied by the  cyclohexane oxidation with H2O2 as an oxidant. The catalytic results show that the catalyst has the better activity and stability in cyclohexane oxidation. Amongst all the solvents ,cyclohexane conversion is the highest (55.1%) when acetonitrile was used as solvent. The influences of time and temperature on cyclohexane conversion are also further investigated. The considerable reactive condition should be reaction time (10～12 h), reaction temperature (80～90 ℃) respectively.
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Flocculatility and Mechanism of MDFFA Composite System
DONG Jun-yan, GAO Mang-lai,CHEN Rui, LI Jin-jin
2009, 22 (3): 60-65. DOI:10.3696/j.issn.1006-396X.2009.03.015
Abstract ( ) PDF ( 563KB ) ( ) 　　
The flocculability of composite system of molecular deposition filming flooding agent(MDFFA) and fluorine-containing cationic surfactant (FC-4), decamethonium bromide (DMB), hexadecyl trimethyl ammonium (CTAB) was investigated, and the preliminary flocculation mechanism of these composite flocculants was discussed by analyzing Zeta potential on bentonite suspension. The results show that DMB and MDFFA have better flocculation capability on bentonite suspension. FC-4/MDFFA composite system has synergistic effect. 10%FC-4, 90%DMB and 10%CTAB appear best flocculability on bentonite suspension. Several tests on treating oil emulsion contenting bentonite reveal that the floccculability follows the order CTAB> DMB>MDFFA>FC-4. 90%FC-4, 70%DMB and 90%CTAB have best flocculability. Flocculating mechanism of FC-4, CTAB and their mixed systems with MDFFA is mainly charge neutralization, while MDFFA,DMB and DMB/MDFFA composite system is mainly compress electricity double layer.
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Calculation and Analysis for Wellbore Temperature Field Reverse Circulation Kill
LI Hao,SUN Bao-jiang,MA Yong-qian,WANG Zhi-yuan,et al
2009, 22 (3): 66-70. DOI:10.3696/j.issn.1006-396X.2009.03.016
Abstract ( ) PDF ( 415KB ) ( ) 　　
In order to make reverse circulation kill well run，it was necessary to understand the relationship between the wellbore temperature and the external environment and kill fluid thermo physical properties．From the reverse circulation kill
characteristics and to the basic heat transfer theory，the reverse circulation kill calculation model was established．The factors influencing the wellbore temperature were analyzed． The results show that kill fluid capacity， kill fluid heat capacity，geothermal gradient，well depth，kill circulating time and inlet temperature have dominant influences on the temperature of the wellbore．Changing the kill fluid capacity and inlet temperature can adjust the wellbore temperature effectively.
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Elastic － Plastic Fracture Analysis for Internal Axial Surface Half Elliptical Cracks in Oil & Gas Pipeline
BAI Yong-qiang,WANG Tong,Lv Liang-hai,SHUAI Jian
2009, 22 (3): 71-74. DOI:10.3696/j.issn.1006-396X.2009.03.017
Abstract ( ) PDF ( 267KB ) ( ) 　　
The elastic－plastic fracture analysis for internal axial surface half elliptical cracks oil & gas in pipeline were provided and the corrected J－integral estimation method was established． First，based on detailed 3－D FE results using
deformation plasticity，some fully plastic solutions for fully plastic J components were tabulated for the mean radius－to－thickness ratio，the crack depth－to－ length ratio，the crack depth－to－thickness ratio，the strain hardening index for the R－O material ，and the location along the semi－elliptical crack front．Second，by means of the analysis of these fully plastic solutions for fully plastic J components，the improper of the EPRI method was described．Finally，based on the FE results，the GE／EPRI－type J estimation equation along the crack front was proposed．Then the J values calculated by FE，EPRI and the method were compared，which demonstrates the accuracy of the J－integral estimation method．
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Simulation and Optimization for New Type VSP Logging Tool Eccentering Machinery Based on ADAMS
XING Jia-le, LIU Li
2009, 22 (3): 75-78. DOI:10.3696/j.issn.1006-396X.2009.03.018
Abstract ( ) PDF ( 401KB ) ( ) 　　
New type VSP logging tool uses hydraulic and mechanical complex st ructure. It can avoid the failure of breaking eccentering machinery arms which caused by seizure of driving screw , and can withdraw the logging tool safely. Based on
ADAMS sof tware a mathematics model was established by choosing sensitive unit s size as varieties to do the analysis of dynamicsimulation, and also used penalty function to optimize the system. The simulation model also took eccentering machinery arms and support arms into consideration to adopt different well’s diameter, the range of testing well could be f rom 100 to 420 mm.
Af ter the experimental stage, this system can work steadily 2 000 times without stop under the condition of 180 ℃, water, drilling mud, oil and other kinds of erosive fluid, and the t ravel length can reach 10 000 m, the reliability arrives above 98 %. The using of virtual prototyping shorts the design periodicity, and the theoretical data is relative to the actual data which is obtained through experiment f rom physical prototype. New type VSP logging tool eccentering machinery is improved f rom the older one, and can avoid the t rouble of disassembly and save the cost a great deal.
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Design of Annular Rubber Seal for t he Oil - Water Well Device Under Pressure Operation
CUI Bin,WU Ying-xiang,XU Jing-yu
2009, 22 (3): 79-82. DOI:10.3696/j.issn.1006-396X.2009.03.019
Abstract ( ) PDF ( 416KB ) ( ) 　　
The rubber seal issue under operating system has been studied by the theory of dynamic sealing. The deformation and st ress dist ribution of rubber material were calculated under the well in - pressure and sealing out - pressure using the non -
linear finite element . Through the experimental study of the rubber st rength and fatigue, the intensity limit and the fatigue life were obtained. According to the study results, a new type of sealing equipment was designed by adding the reinforcing steel bar into rubber core to reduce the maximum shear st ress, so as to solve the problems of dynamic seal under hyperbaric pressure.

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The Research of Magnetic Flux Leakage Testing Technology for Well Casing
CHEN Jin-zhong， LIN Li， SONG Qiang
2009, 22 (3): 83-85. DOI:10.3696/j.issn.1006-396X.2009.03.020
Abstract ( ) PDF ( 380KB ) ( ) 　　
Based on the complicated environment well casing laid and size requirement of down - hole , the hardware system suitable to casing inspection was developed to acquire and store the magnetic flux leakage signal , which was cont rolled by dual- MCU. The up - hole location acquiring system was also developed without encoder, by which it can avoid complicated mechanical st ructure and low reliability. The sof tware system developed by Labview could display the magnetic flux leakage signal, and the magnetic flux leakage signal and location were correlated based on wavelet modulus maxima algorithm. Finally the experiment result indicates that the system can detect s the defect s of well casing and displays the magnetic flux leakage signal.
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Application of BP Neura1 Network in the Gel Point Prediction of Blend Crude Oil
HOU Lei,XU Xin-yu,LIU Xiu-lian
2009, 22 (3): 86-88. DOI:10.3696/j.issn.1006-396X.2009.03.021
Abstract ( ) PDF ( 282KB ) ( ) 　　
The BP neura1 network and the tested gel points of the blend crude oil were studied. A prediction model based on the BP neura1 network was established to calculate the gel point of the blend crude oil. The back-propagation artificial neural network has the satisfactory nonlinear prediction ability. The gel points of the component crude oil and their proportions were taken as the input vector and the gel points of the blend crude oil as the output one. The relationship between the gel points of the blend crude oil and the component crude oil was researched. The results show that the gel point prediction model based on the BP neura1 network is better than other gel point prediction models. The maximum average deviation of the predicted gel point is only 0.128 °C and the average absolute deviation is 0.022 °C. 
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Simultaneous Design of Low － Pass Filter and Output Feedback Controller in Robust Repetitive Control Systems
ZHAO Fu,LIU Yu,SU Bao-ku,YANG Yu
2009, 22 (3): 89-95. DOI:10.3696/j.issn.1006-396X.2009.03.022
Abstract ( ) PDF ( 265KB ) ( ) 　　
The method for the linear system with time－varying norm－bounded uncertainties was presented to reject periodic disturbances and to track periodic reference signals with a known period effectively，which can design the low－pass filter in the repetitive controller and the output feedback controller simultaneously．The repetitive control system was converted to a time－delay system；Based on Lyapunov theory，a sufficient condition was derived in terms of a linear matrix inequality （LMI），which ensures robust stability of the time － delay system．Based on the derived condition，the problem of designing the low－pass filter and the output feedback controller was converted to a nonlinear matrix inequality problem．By using the linear matrix inequality （LMI） and cone complementarity linearization （CCL） algorithm，an iterative algorithm was presented to calculate the larger cut－off angular frequency of a low－pass filter and the corresponding output feedback controller parameters．The numerical example is presented to illustrate the validity of the proposed method．
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Image Segmentation Algorithm Based on Monte Carlo Methods and Rough Entropy Standard
ZHANG Xue-feng,SHANG Jin-kui
2009, 22 (3): 94-98. DOI:10.3696/j.issn.1006-396X.2009.03.023
Abstract ( ) PDF ( 340KB ) ( ) 　　
The image segmentation algorithm was presented．First of all，it divides the image into some equal size image sub－pieces according with some rules，carries out certain scale random sampling on the image sub－pieces using Monte Carlo
Methods，and computes the rough entropy of the sample，and then divides the image by the image gray scale corresponding to the maximum rough entropy．The speed of the image segmentation is largely improved，while adopting the less image sub－pieces to get better segmentation effect． And it has been confirmed in reducing the consumption of the computer is very effective in experiments using MATLAB，and the threshold is satisfied．
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