An industrial scale propylene production via oxidative dehydrogenation of propane(ODHP)in multi-tubular reactors was modeled.Multi-tubular fixed-bed reactor used for ODHP process,employing 10000 of small diameter tube...An industrial scale propylene production via oxidative dehydrogenation of propane(ODHP)in multi-tubular reactors was modeled.Multi-tubular fixed-bed reactor used for ODHP process,employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows.Herein,a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence ole fin over V_2O_5/γ-Al_2O_3catalyst was presented.Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions,gas process and coolant temperatures,as well as other parameters affecting the reactor performance such as pressure.Furthermore,the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%.The optimized length of the reactor needed to reach 100%conversion of the oxygen was theoretically determined.For the single-bed reactor the optimized length of 11.96 m including 0.5m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72m for the first and 7.32 m for the second reactor were calculated.Ultimately,the use of a distributed oxygen feed with limited number of injection points indicated a signi ficant improvement on the reactor performance in terms of propane conversion and propylene selectivity.Besides,this concept could overcome the reactor runaway temperature problem and enabled operations at the wider range of conditions to obtain enhanced propylene production in an industrial scale reactor.展开更多
The potential of di-(m-Formylphenol)-1,2-cyclohexandiimine as an environmentally friendly corrosion inhibitor for steel was investigated in 1 mol/L HCl using potentiodynamic polarization, electrochemical impedance spe...The potential of di-(m-Formylphenol)-1,2-cyclohexandiimine as an environmentally friendly corrosion inhibitor for steel was investigated in 1 mol/L HCl using potentiodynamic polarization, electrochemical impedance spectroscopy and chronoamperometry measurements. All electrochemical measurements suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25 °C to 65 °C. It is found that the adsorption of this inhibitor follows the Langmuir adsorption isotherms. The value of activation energy and the thermodynamic parameters such as ΔHads, ΔSads, Kads and ΔGads were calculated by the corrosion currents at different temperatures using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of inhibitor was examined by scanning electron microscopy(SEM) images.展开更多
In this study, a comprehensive three-dimensional dynamic model was developed for simulating the flow behavior and catalytic coupling reactions for direct synthesis of dimethyl ether(DME) from syngas including CO2 in a...In this study, a comprehensive three-dimensional dynamic model was developed for simulating the flow behavior and catalytic coupling reactions for direct synthesis of dimethyl ether(DME) from syngas including CO2 in a fixed bed reactor at commercial scale under both adiabatic and isothermal conditions. For this purpose, a computational fluid dynamic(CFD) simulation was carried out through which the standard k-ε model with 10% turbulence tolerations was implemented. At first, an adiabatic fixed bed reactor was simulated and the obtained results were compared with those of an equivalent commercial slurry reactor. Then the concentration and temperature profiles along the reactor were predicted. Consequently, the optimum temperature, pressure, hydrogen to carbon monoxide ratio in the feedstock and the reactor height under different operation conditions were determined. Finally, the results obtained from this three-dimensional dynamic model under appropriate industrial boundary conditions were compared with those of others available in literature to verify the model. Next, through changing the boundary conditions, the simulation was performed for an isothermal fixed bed reactor. Furthermore, it was revealed that, under isothermal conditions, the performed equilibrium simulations were done for a single phase system. Considering the simultaneous effects of temperature and pressure, the optimum operation conditions for the isothermal and adiabatic fixed bed reactors were investigated. The results of the H2+CO conversions indicated that, under isothermal condition, higher conversion could be achieved, in compared with that under adiabatic conditions. Then, the effects of various operating parameters, including the pressure and temperature, of the reactor on the DME production were examined. Ultimately, the CFD modeling results generated in the present work showed reasonable agreement with previously obtained data available in the literature.EnvironmenEtanl vpiorollnumtioennt aaln dp oiltlsu tpiroenv eanntdio ints aprere mveanjtoiro np raorbel emmasj展开更多
The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the ...The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production,such as permeability.Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area.In this study,an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration.The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.Then,using surface tension tests,its critical micelle concentration(CMC)was determined.Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration.Surfactant adsorption on porous media was calculated using flooding.Finally,the surfactant foamability was investigated using a Ross-Miles foam generator.According to the results,the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs.A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments.Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K,the contact angles at treatment times of 30,60,120 and 240 min were obtained 87.94°,93.50°,99.79°and 106.03°,respectively.However,this ability varies at different surfactant concentrations and temperatures.The foamability test also shows the suitable stability of the foam generated by the surfactant,and a foam half-life time of 13 min was obtained for the surfactant at CMC.展开更多
The corrosion inhibition of mild steel in 1 mol/L HCl by N, N′-bis (2-hydroxybenzaldehyde)-1, 3-propandiimine (2-HBP) has been investigated by using potentiodynamic polarization, electrochemical impedance spectroscop...The corrosion inhibition of mild steel in 1 mol/L HCl by N, N′-bis (2-hydroxybenzaldehyde)-1, 3-propandiimine (2-HBP) has been investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and chronoamperometry measurements. The experimental results suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. Polarization curves reveal that this organic compound is a mixed type inhibitor. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25℃ to 65℃. The experimentally obtained adsorption isotherms follow the Langmuir equation. Activation and thermodynamic adsorption parameters such as E a , ΔH, ΔS, K ads and ΔG ads were calculated by the corrosion currents at different temperatures and using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of 2-HBP was examined by atomic force microscope (AFM) images.展开更多
Nickel modified NiOOH electrodes were used for the electrocatalytic oxidation of ethanol in alkaline so lutions. The electro-oxidation of ethanol in a 1 mol/L NaOH solution at different concentrations of ethanol was s...Nickel modified NiOOH electrodes were used for the electrocatalytic oxidation of ethanol in alkaline so lutions. The electro-oxidation of ethanol in a 1 mol/L NaOH solution at different concentrations of ethanol was stu died by ac impedance spectroscopy. Electrooxidation of ethanol on Ni shows negative resistance on impedance plots. The impedance shows different patterns at different applied anodic potential. The influence of the electrode potential on impedance was studied and a quantitative explanation for the impedance of ethanol oxidation was given by means of a proposed mathematical model. At potentials higher than 0.52 V(vs. Ag/AgCl), a pseudoinductive behavior was observed, but at those higher than 0.57 V, impedance patterns were reversed to the second and third quadrants. The conditions required for the reversing of impedance pattern were delineated with the impedance model.展开更多
Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward wat...Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward water-wet using various surfactant agents including cationic,anionic,non-ionic,and amphoteric varieties.In this study,two amino-acid based surfactants,named lauroyl arginine(L-Arg)and lauroyl cysteine(L-Cys),were synthesized and used to reduce the IFT of oil–water systems and alter the wettability of carbonate rocks,thus improving oil recovery from oil-wet carbonate reservoirs.The synthesized surfactants were characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses,and the critical micelle concentration(CMC)of surfactant solutions was determined using conductivity,pH,and turbidity techniques.Experimental results showed that the CMCs of L-Arg and L-Cys solutions were 2000 and 4500 ppm,respectively.It was found that using L-Arg and L-Cys solutions at their CMCs,the IFT and contact angle were reduced from 34.5 to 18.0 and15.4 mN/m,and from 144°to 78°and 75°,respectively.Thus,the L-Arg and L-Cys solutions enabled approximately 11.9%and 8.9%additional recovery of OOIP(original oil in place).It was identified that both amino-acid surfactants can be used to improve oil recovery due to their desirable effects on the EOR mechanisms at their CMC ranges.展开更多
A stable copper(hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1 000 mV.It can be used for electrochemical studies in the range of -250 to 1000 mV w...A stable copper(hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1 000 mV.It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper.During an anodic potential sweep,the electro-oxidation of saccharose on Cu occurred by the formation of CuⅢ and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials.A mechanism based on the electro-chemical generation of CuⅢ active sites and their subsequent consumption by saccharose was proposed,and the rate law and kinetic parameters were obtained.The charge transfer resistance from theoretical and impedance studies was used to verify the mechanism.Under chronoamperometry regimes,the reaction followed Cottrellian behavior.The transfer of up to 21 electrons was observed in further investigations of the electro-oxidation of saccharose on a(hydr)oxide Cu rotating disk electrode.展开更多
The microstructure and corrosion resistance of dissimilar weld-joints between stainless steel SAF 2205 and stainless steel AISI 316 L were investigated. Welding was accomplished by different types of welding wires AWS...The microstructure and corrosion resistance of dissimilar weld-joints between stainless steel SAF 2205 and stainless steel AISI 316 L were investigated. Welding was accomplished by different types of welding wires AWS ER 347, AWS ER 316 L and AWS ER 309 L. To verify soundness of welded samples, nondestructive tests were performed. Metallographic samples were prepared from cross-section areas of weldjoints to investigate microstructure of different regions of weld-joints by optical microscopy and scanning electron microscopy. Corrosion resistance of weld-joints was evaluated in NaCl solution by potentiodynamic polarization and electrochemical impedance techniques. In the weld metal AWS ER 347, the brittle sigma phase was created, resulting in the decrease of weld-joint corrosion resistance. According to the results of metallurgical investigations and corrosion tests, welding wire AWS ER 309 L was suitable for welding duplex stainless steel(SAF 2205) to austenitic stainless steel(AISI 316L) by gas tungsten arc welding(GTAW)process.展开更多
Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy(EIS) a...Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy(EIS) and immersion test. Open circuit potential(OCP) measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy(TEM) photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.展开更多
The electrochemical behavior of steel alloy in ethylene glycol-water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained show...The electrochemical behavior of steel alloy in ethylene glycol-water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl- ions and the adsorption isotherm basically obeys the Flory-Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.展开更多
The inhibition ability of 2-amino-5-nitrothiazole(Nitramine) against the corrosion of AISI steel 4130 in 1 mol/L HCl solution was evaluated by polarization,electrochemical impedance spectroscopy(EIS) and chronoamperom...The inhibition ability of 2-amino-5-nitrothiazole(Nitramine) against the corrosion of AISI steel 4130 in 1 mol/L HCl solution was evaluated by polarization,electrochemical impedance spectroscopy(EIS) and chronoamperometry.Polarization studies indicated that nitramine retards both the cathodic and anodic reactions through chemical adsorption and blocks the active corrosion sites.The adsorption of this compound obeyed the Temkin's adsorption isotherm.The inhibition efficiency was increased with inhibitor concentration as well as temperature.EIS data were analysed by equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased.Kinetic and thermodynamic parameters such as activation energy,enthalpy,entropy and free energy of activation and adsorption were calculated.Atomic force microscopy and optical microscopy were used to study the steel surface with and without inhibitor.展开更多
The electrochemical behavior of steel alloy in 30%ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements.The results obtained showed ...The electrochemical behavior of steel alloy in 30%ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements.The results obtained showed that corrosion rate did not change significantly at different rotating speeds.The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained.It was found that surface passivation occurred in the presence of the inhibitor.The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl-and the adsorption isotherm basically obeys the Langmuir adsorption isotherm.Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.展开更多
Estimation of rock mechanic parameters is an important issue in reservoir management.Uniaxial compressive strength(UCS)and elastic modulus are the most important factors in determining the rock mechanic parameters in ...Estimation of rock mechanic parameters is an important issue in reservoir management.Uniaxial compressive strength(UCS)and elastic modulus are the most important factors in determining the rock mechanic parameters in petroleum engineering studies.Accessibility to the parameters in fields such as designing fracture,analyzing of wellbore stability and drilling programming are very useful.The most accurate method to assign the aforementioned parameters is measuring these parameters in a laboratory.Laboratory determination of these parameters is problematic work due to technology issues,lack of laboratory equipment and coring problems in oil and gas wells,so indirect estimation of these parameters is required.Using well log data is the cheapest and most available approach in order to indirectly estimate these parameters.In this investigation,different models including multiple linear regression(MLR)and artificial neural network(ANN)(i.e.,multi linear perceptron(MLP)and radial basis function(RBF))were utilized for prediction of UCS via the three parameters of porosity,density and water saturation.These data were obtained from analysis of sonic,neutron,gamma ray and electric logs.The best results were obtained from a 3-15-1 MLP network which included one hidden layer and 15 neurons from the hidden layer using the trial and error method,and a 3-17-1 RBF which included 17 hidden neurons and a spread ò of 1.6.The core data from one of the carbonate Iranian oil fields(Asmari reservoir)were utilized for training,validation and testing of the networks,and correlation coefficients of 0.68,0.90 and 0.83 were obtained for MLR,MLP and RBF,respectively.展开更多
Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands.Among of all operative factors,wettability may be the foremost par...Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands.Among of all operative factors,wettability may be the foremost parameter affecting residual oil saturation in all stage of oil recovery.Although wettability alteration is one of the methods which enhance oil recovery from the petroleum reservoir.Recently,the studies which focused on this subject were more than the past and many contributions have been made on this area.The main objective of the current study is experimentally investigation of the two nonionic surfactants effects on altering wettability of reservoir rocks.Purpose of this work is to change the wettability to preferentially the water-wet condition.Also reducing the residual oil saturation(Sor)is the other purpose of this work.The wettability alteration of reservoir rock is measured by two main quantitative methods namely contact angle and the USBM methods.Results of this study showed that surfactant flooding is more effective in oil-wet rocks to change their wettability and consequently reducing Sor to a low value.Cedar(Zizyphus Spina Christi)is low priced,absolutely natural,and abundantly accessible in the Middle East and Central Asia.Based on the results,this material can be used as a chemical surfactant in field for enhancing oil recovery.展开更多
Rising global energy demand has encouraged engineers to create and design new methods to improve oil recovery from reservoirs.In this study,feasibility of using Henna extract as a natural surfactant and synthesized na...Rising global energy demand has encouraged engineers to create and design new methods to improve oil recovery from reservoirs.In this study,feasibility of using Henna extract as a natural surfactant and synthesized nanoparticles(Titanium dioxide(TiO2),Silicon dioxide(SiO2),Graphene and composite of TiO2-Graphene)for reduction of oil-water interfacial tension has been experimentally investigated.Nanoparticles were synthesized via sol-gel method and XRD,FESEM,EDAX and FTIR tests were conducted to confirm the authenticity of this synthesizing materials.Nano-surfactants were stabled with a natural water-based suspending surfactant called Tragacanth extract,which could be introduced as a practical substitute for industrial nanoparticles'stabilizers in oil industry.After CMC determination of Henna extract surfactant,the optimal concentration of Tragacanth extract surfactant,with the purpose of nano-surfactants’stabilization,was determined through particle size and zeta potential tests.Results of interfacial tension(IFT)measurements showed that the increase of Henna extract concentration from 0 wt%to 10 wt%reduced IFT between kerosene and water from 37.23 to 15.24 mN/m.Furthermore,adding 1 wt%of synthesized TiO2 nanoparticle to the Henna extract surfactant at its CMC value reduced IFT from 18.43 to 14.57 mN/m.As an impact of this significant reduction in IFT value,oil recovery factor could be improved drastically during EOR operations.Results proved that TiO2 nano-surfactant was as effective as industrial surfactants,which put human's and environment's health at risk and impose heavy economic strain on governments.展开更多
Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 ...Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 injection mobility,increase water viscosity and store/remove produced greenhouse CO2 gas safely.Another enhanced oil recovery method is smart water injection at which the ions in brine are modified in order to make controlled reactions with distributed ions on the surface of rock to cause more hydrocarbon recovery.Therefore,combination of these two methods may also have a great effect on enhancing oil recovery or may result in recovery factor less than each method used alone.In this paper hybrid smart carbonated water injection method is investigated to study its applicability in oil recovery using core flooding setup.The experimental core flooding setup was designed to perform different types of EOR methods for the sake of recovery comparison with the new hybrid method.The effect of both brine content and volume of CO2 is determining in hybrid EOR assessment.The main findings of this work show that the hybrid smart carbonated water results in the highest recovery factor in comparison to the most well-known EOR methods for carbonate cores.展开更多
Knowledge about reservoir fluid properties such as bubble point pressure(Pb)plays a vital role in improving reliability of oil reservoir simulation.In this work,hybrid of swarm intelligence and artificial neural netwo...Knowledge about reservoir fluid properties such as bubble point pressure(Pb)plays a vital role in improving reliability of oil reservoir simulation.In this work,hybrid of swarm intelligence and artificial neural network(ANN)as a robust and effective method was executed to determine the Pb of crude oil samples.In addition,the exactly precise Pb data samples reported in the literatures were employed to create and validate the PSO-ANN model.To prove and depict the reliability of the smart model developed in this study for estimating Pb of crude oils,the conventional approaches were applied on the same data set.Based on the results generated by PSO-ANN model and other conventional methods and equation of states(EOS),the PSO-ANN model is a reliable and accurate approach for estimating Pb of crude oils.This is certified by high value of correlation coefficient(R2)and insignificant value of average absolute relative deviation(AARD%)which are obtained from PSO-ANN outputs.Outcomes of this study could help reservoir engineers to have better understanding of reservoir fluid behavior in absence of reliable and experimental data samples.展开更多
Scale formation due to the mixing of injection water with formation water causes formation damage and reduction in petroleum production.By using scale inhibitors,scale formation/scaling could be prevented.In this work...Scale formation due to the mixing of injection water with formation water causes formation damage and reduction in petroleum production.By using scale inhibitors,scale formation/scaling could be prevented.In this work,static experiments were performed with rapid controlled precipitation tests,which were undertaken using three different scale inhibitors namely Falat scale inhibitor,Scahib 760 scale inhibitor and Scahib 780 scale inhibitor.Results show that parameters such as temperature and pH have significant effects on scale inhibitor efficiency.In this study,at pH of 7.8e9 it was found that an increase in pH can lead to a decrease in SI efficiency.In addition,acquired data shows that Falat scale inhibitor is more efficient at 45C but scale inhibitors(Scahib 760,780)have better efficiencies at 25C.SEM tests were performed to find structure deformation and morphology of precipitation crystals,which indicated that scale inhibitor can have various effects on crystal's shapes.Finally,dynamic tests were performed with coreflood equipment that indicated higher recovery by using the scale inhibitors.The dynamic tests results show that the recovery factor in the presence of Scahib 760 scale inhibitor is about 58%and breakthrough time is 2099(sec).In the absence of scale inhibitor,the recovery factor is about 52%and breakthrough time is 2720(sec).展开更多
文摘An industrial scale propylene production via oxidative dehydrogenation of propane(ODHP)in multi-tubular reactors was modeled.Multi-tubular fixed-bed reactor used for ODHP process,employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows.Herein,a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence ole fin over V_2O_5/γ-Al_2O_3catalyst was presented.Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions,gas process and coolant temperatures,as well as other parameters affecting the reactor performance such as pressure.Furthermore,the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%.The optimized length of the reactor needed to reach 100%conversion of the oxygen was theoretically determined.For the single-bed reactor the optimized length of 11.96 m including 0.5m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72m for the first and 7.32 m for the second reactor were calculated.Ultimately,the use of a distributed oxygen feed with limited number of injection points indicated a signi ficant improvement on the reactor performance in terms of propane conversion and propylene selectivity.Besides,this concept could overcome the reactor runaway temperature problem and enabled operations at the wider range of conditions to obtain enhanced propylene production in an industrial scale reactor.
文摘The potential of di-(m-Formylphenol)-1,2-cyclohexandiimine as an environmentally friendly corrosion inhibitor for steel was investigated in 1 mol/L HCl using potentiodynamic polarization, electrochemical impedance spectroscopy and chronoamperometry measurements. All electrochemical measurements suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25 °C to 65 °C. It is found that the adsorption of this inhibitor follows the Langmuir adsorption isotherms. The value of activation energy and the thermodynamic parameters such as ΔHads, ΔSads, Kads and ΔGads were calculated by the corrosion currents at different temperatures using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of inhibitor was examined by scanning electron microscopy(SEM) images.
文摘In this study, a comprehensive three-dimensional dynamic model was developed for simulating the flow behavior and catalytic coupling reactions for direct synthesis of dimethyl ether(DME) from syngas including CO2 in a fixed bed reactor at commercial scale under both adiabatic and isothermal conditions. For this purpose, a computational fluid dynamic(CFD) simulation was carried out through which the standard k-ε model with 10% turbulence tolerations was implemented. At first, an adiabatic fixed bed reactor was simulated and the obtained results were compared with those of an equivalent commercial slurry reactor. Then the concentration and temperature profiles along the reactor were predicted. Consequently, the optimum temperature, pressure, hydrogen to carbon monoxide ratio in the feedstock and the reactor height under different operation conditions were determined. Finally, the results obtained from this three-dimensional dynamic model under appropriate industrial boundary conditions were compared with those of others available in literature to verify the model. Next, through changing the boundary conditions, the simulation was performed for an isothermal fixed bed reactor. Furthermore, it was revealed that, under isothermal conditions, the performed equilibrium simulations were done for a single phase system. Considering the simultaneous effects of temperature and pressure, the optimum operation conditions for the isothermal and adiabatic fixed bed reactors were investigated. The results of the H2+CO conversions indicated that, under isothermal condition, higher conversion could be achieved, in compared with that under adiabatic conditions. Then, the effects of various operating parameters, including the pressure and temperature, of the reactor on the DME production were examined. Ultimately, the CFD modeling results generated in the present work showed reasonable agreement with previously obtained data available in the literature.EnvironmenEtanl vpiorollnumtioennt aaln dp oiltlsu tpiroenv eanntdio ints aprere mveanjtoiro np raorbel emmasj
文摘The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production,such as permeability.Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area.In this study,an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration.The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.Then,using surface tension tests,its critical micelle concentration(CMC)was determined.Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration.Surfactant adsorption on porous media was calculated using flooding.Finally,the surfactant foamability was investigated using a Ross-Miles foam generator.According to the results,the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs.A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments.Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K,the contact angles at treatment times of 30,60,120 and 240 min were obtained 87.94°,93.50°,99.79°and 106.03°,respectively.However,this ability varies at different surfactant concentrations and temperatures.The foamability test also shows the suitable stability of the foam generated by the surfactant,and a foam half-life time of 13 min was obtained for the surfactant at CMC.
文摘The corrosion inhibition of mild steel in 1 mol/L HCl by N, N′-bis (2-hydroxybenzaldehyde)-1, 3-propandiimine (2-HBP) has been investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and chronoamperometry measurements. The experimental results suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. Polarization curves reveal that this organic compound is a mixed type inhibitor. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25℃ to 65℃. The experimentally obtained adsorption isotherms follow the Langmuir equation. Activation and thermodynamic adsorption parameters such as E a , ΔH, ΔS, K ads and ΔG ads were calculated by the corrosion currents at different temperatures and using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of 2-HBP was examined by atomic force microscope (AFM) images.
文摘Nickel modified NiOOH electrodes were used for the electrocatalytic oxidation of ethanol in alkaline so lutions. The electro-oxidation of ethanol in a 1 mol/L NaOH solution at different concentrations of ethanol was stu died by ac impedance spectroscopy. Electrooxidation of ethanol on Ni shows negative resistance on impedance plots. The impedance shows different patterns at different applied anodic potential. The influence of the electrode potential on impedance was studied and a quantitative explanation for the impedance of ethanol oxidation was given by means of a proposed mathematical model. At potentials higher than 0.52 V(vs. Ag/AgCl), a pseudoinductive behavior was observed, but at those higher than 0.57 V, impedance patterns were reversed to the second and third quadrants. The conditions required for the reversing of impedance pattern were delineated with the impedance model.
文摘Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward water-wet using various surfactant agents including cationic,anionic,non-ionic,and amphoteric varieties.In this study,two amino-acid based surfactants,named lauroyl arginine(L-Arg)and lauroyl cysteine(L-Cys),were synthesized and used to reduce the IFT of oil–water systems and alter the wettability of carbonate rocks,thus improving oil recovery from oil-wet carbonate reservoirs.The synthesized surfactants were characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses,and the critical micelle concentration(CMC)of surfactant solutions was determined using conductivity,pH,and turbidity techniques.Experimental results showed that the CMCs of L-Arg and L-Cys solutions were 2000 and 4500 ppm,respectively.It was found that using L-Arg and L-Cys solutions at their CMCs,the IFT and contact angle were reduced from 34.5 to 18.0 and15.4 mN/m,and from 144°to 78°and 75°,respectively.Thus,the L-Arg and L-Cys solutions enabled approximately 11.9%and 8.9%additional recovery of OOIP(original oil in place).It was identified that both amino-acid surfactants can be used to improve oil recovery due to their desirable effects on the EOR mechanisms at their CMC ranges.
文摘A stable copper(hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1 000 mV.It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper.During an anodic potential sweep,the electro-oxidation of saccharose on Cu occurred by the formation of CuⅢ and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials.A mechanism based on the electro-chemical generation of CuⅢ active sites and their subsequent consumption by saccharose was proposed,and the rate law and kinetic parameters were obtained.The charge transfer resistance from theoretical and impedance studies was used to verify the mechanism.Under chronoamperometry regimes,the reaction followed Cottrellian behavior.The transfer of up to 21 electrons was observed in further investigations of the electro-oxidation of saccharose on a(hydr)oxide Cu rotating disk electrode.
文摘The microstructure and corrosion resistance of dissimilar weld-joints between stainless steel SAF 2205 and stainless steel AISI 316 L were investigated. Welding was accomplished by different types of welding wires AWS ER 347, AWS ER 316 L and AWS ER 309 L. To verify soundness of welded samples, nondestructive tests were performed. Metallographic samples were prepared from cross-section areas of weldjoints to investigate microstructure of different regions of weld-joints by optical microscopy and scanning electron microscopy. Corrosion resistance of weld-joints was evaluated in NaCl solution by potentiodynamic polarization and electrochemical impedance techniques. In the weld metal AWS ER 347, the brittle sigma phase was created, resulting in the decrease of weld-joint corrosion resistance. According to the results of metallurgical investigations and corrosion tests, welding wire AWS ER 309 L was suitable for welding duplex stainless steel(SAF 2205) to austenitic stainless steel(AISI 316L) by gas tungsten arc welding(GTAW)process.
文摘Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy(EIS) and immersion test. Open circuit potential(OCP) measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy(TEM) photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.
文摘The electrochemical behavior of steel alloy in ethylene glycol-water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl- ions and the adsorption isotherm basically obeys the Flory-Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.
文摘The inhibition ability of 2-amino-5-nitrothiazole(Nitramine) against the corrosion of AISI steel 4130 in 1 mol/L HCl solution was evaluated by polarization,electrochemical impedance spectroscopy(EIS) and chronoamperometry.Polarization studies indicated that nitramine retards both the cathodic and anodic reactions through chemical adsorption and blocks the active corrosion sites.The adsorption of this compound obeyed the Temkin's adsorption isotherm.The inhibition efficiency was increased with inhibitor concentration as well as temperature.EIS data were analysed by equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased.Kinetic and thermodynamic parameters such as activation energy,enthalpy,entropy and free energy of activation and adsorption were calculated.Atomic force microscopy and optical microscopy were used to study the steel surface with and without inhibitor.
文摘The electrochemical behavior of steel alloy in 30%ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements.The results obtained showed that corrosion rate did not change significantly at different rotating speeds.The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained.It was found that surface passivation occurred in the presence of the inhibitor.The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl-and the adsorption isotherm basically obeys the Langmuir adsorption isotherm.Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.
基金The authors would like to thank the National Iranian South Oil Company(NISOC)for their support of the experimental data.
文摘Estimation of rock mechanic parameters is an important issue in reservoir management.Uniaxial compressive strength(UCS)and elastic modulus are the most important factors in determining the rock mechanic parameters in petroleum engineering studies.Accessibility to the parameters in fields such as designing fracture,analyzing of wellbore stability and drilling programming are very useful.The most accurate method to assign the aforementioned parameters is measuring these parameters in a laboratory.Laboratory determination of these parameters is problematic work due to technology issues,lack of laboratory equipment and coring problems in oil and gas wells,so indirect estimation of these parameters is required.Using well log data is the cheapest and most available approach in order to indirectly estimate these parameters.In this investigation,different models including multiple linear regression(MLR)and artificial neural network(ANN)(i.e.,multi linear perceptron(MLP)and radial basis function(RBF))were utilized for prediction of UCS via the three parameters of porosity,density and water saturation.These data were obtained from analysis of sonic,neutron,gamma ray and electric logs.The best results were obtained from a 3-15-1 MLP network which included one hidden layer and 15 neurons from the hidden layer using the trial and error method,and a 3-17-1 RBF which included 17 hidden neurons and a spread ò of 1.6.The core data from one of the carbonate Iranian oil fields(Asmari reservoir)were utilized for training,validation and testing of the networks,and correlation coefficients of 0.68,0.90 and 0.83 were obtained for MLR,MLP and RBF,respectively.
文摘Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands.Among of all operative factors,wettability may be the foremost parameter affecting residual oil saturation in all stage of oil recovery.Although wettability alteration is one of the methods which enhance oil recovery from the petroleum reservoir.Recently,the studies which focused on this subject were more than the past and many contributions have been made on this area.The main objective of the current study is experimentally investigation of the two nonionic surfactants effects on altering wettability of reservoir rocks.Purpose of this work is to change the wettability to preferentially the water-wet condition.Also reducing the residual oil saturation(Sor)is the other purpose of this work.The wettability alteration of reservoir rock is measured by two main quantitative methods namely contact angle and the USBM methods.Results of this study showed that surfactant flooding is more effective in oil-wet rocks to change their wettability and consequently reducing Sor to a low value.Cedar(Zizyphus Spina Christi)is low priced,absolutely natural,and abundantly accessible in the Middle East and Central Asia.Based on the results,this material can be used as a chemical surfactant in field for enhancing oil recovery.
文摘Rising global energy demand has encouraged engineers to create and design new methods to improve oil recovery from reservoirs.In this study,feasibility of using Henna extract as a natural surfactant and synthesized nanoparticles(Titanium dioxide(TiO2),Silicon dioxide(SiO2),Graphene and composite of TiO2-Graphene)for reduction of oil-water interfacial tension has been experimentally investigated.Nanoparticles were synthesized via sol-gel method and XRD,FESEM,EDAX and FTIR tests were conducted to confirm the authenticity of this synthesizing materials.Nano-surfactants were stabled with a natural water-based suspending surfactant called Tragacanth extract,which could be introduced as a practical substitute for industrial nanoparticles'stabilizers in oil industry.After CMC determination of Henna extract surfactant,the optimal concentration of Tragacanth extract surfactant,with the purpose of nano-surfactants’stabilization,was determined through particle size and zeta potential tests.Results of interfacial tension(IFT)measurements showed that the increase of Henna extract concentration from 0 wt%to 10 wt%reduced IFT between kerosene and water from 37.23 to 15.24 mN/m.Furthermore,adding 1 wt%of synthesized TiO2 nanoparticle to the Henna extract surfactant at its CMC value reduced IFT from 18.43 to 14.57 mN/m.As an impact of this significant reduction in IFT value,oil recovery factor could be improved drastically during EOR operations.Results proved that TiO2 nano-surfactant was as effective as industrial surfactants,which put human's and environment's health at risk and impose heavy economic strain on governments.
文摘Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 injection mobility,increase water viscosity and store/remove produced greenhouse CO2 gas safely.Another enhanced oil recovery method is smart water injection at which the ions in brine are modified in order to make controlled reactions with distributed ions on the surface of rock to cause more hydrocarbon recovery.Therefore,combination of these two methods may also have a great effect on enhancing oil recovery or may result in recovery factor less than each method used alone.In this paper hybrid smart carbonated water injection method is investigated to study its applicability in oil recovery using core flooding setup.The experimental core flooding setup was designed to perform different types of EOR methods for the sake of recovery comparison with the new hybrid method.The effect of both brine content and volume of CO2 is determining in hybrid EOR assessment.The main findings of this work show that the hybrid smart carbonated water results in the highest recovery factor in comparison to the most well-known EOR methods for carbonate cores.
文摘Knowledge about reservoir fluid properties such as bubble point pressure(Pb)plays a vital role in improving reliability of oil reservoir simulation.In this work,hybrid of swarm intelligence and artificial neural network(ANN)as a robust and effective method was executed to determine the Pb of crude oil samples.In addition,the exactly precise Pb data samples reported in the literatures were employed to create and validate the PSO-ANN model.To prove and depict the reliability of the smart model developed in this study for estimating Pb of crude oils,the conventional approaches were applied on the same data set.Based on the results generated by PSO-ANN model and other conventional methods and equation of states(EOS),the PSO-ANN model is a reliable and accurate approach for estimating Pb of crude oils.This is certified by high value of correlation coefficient(R2)and insignificant value of average absolute relative deviation(AARD%)which are obtained from PSO-ANN outputs.Outcomes of this study could help reservoir engineers to have better understanding of reservoir fluid behavior in absence of reliable and experimental data samples.
文摘Scale formation due to the mixing of injection water with formation water causes formation damage and reduction in petroleum production.By using scale inhibitors,scale formation/scaling could be prevented.In this work,static experiments were performed with rapid controlled precipitation tests,which were undertaken using three different scale inhibitors namely Falat scale inhibitor,Scahib 760 scale inhibitor and Scahib 780 scale inhibitor.Results show that parameters such as temperature and pH have significant effects on scale inhibitor efficiency.In this study,at pH of 7.8e9 it was found that an increase in pH can lead to a decrease in SI efficiency.In addition,acquired data shows that Falat scale inhibitor is more efficient at 45C but scale inhibitors(Scahib 760,780)have better efficiencies at 25C.SEM tests were performed to find structure deformation and morphology of precipitation crystals,which indicated that scale inhibitor can have various effects on crystal's shapes.Finally,dynamic tests were performed with coreflood equipment that indicated higher recovery by using the scale inhibitors.The dynamic tests results show that the recovery factor in the presence of Scahib 760 scale inhibitor is about 58%and breakthrough time is 2099(sec).In the absence of scale inhibitor,the recovery factor is about 52%and breakthrough time is 2720(sec).
