The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected aga...The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected against corrosion by coating. The protective value of a coating system is proportional to the surface preparation;the objectives of the surface preparation are the surface cleanliness and the surface profile of the substrate. The surface preparation is usually achieved by blast cleaning using different types of abrasive. Due to its high hardness and low cost, silica sand has been used extensively for impact abrasion. It is, however, very brittle with most grain disintegrating on impact, causing excessive levels of siliceous dust which is a major health hazard and causes serious environmental pollution. Consequently, it has been banned as impact abrasive material in most countries around the world. Considerable research has been done in the last twenty years to find an impact abrasive material as hard as silica and that respects. So it was important to search for sand substitution among the local abundant minerals in Egypt. Waste product obtained from ilmenite ore extracted from the mine was found to be the most suitable alternative abrasive. This work shows the abrasive types, the occurrence of the ilmenite ore. The chemical properties, physical properties and microscopic examination of the waste were investigated. The obtained result indicates that, the waste product obtained from ilmenite ore can be utilized for abrasion as sand substitution.展开更多
The catalytic activity of CoMoS /CNT towards the Egyptian heavy vacuum gas oil hydrotreating was studied. The delivered CNT was functionalized with 6 mol /L HNO_3. The CNT were loaded with 12% MoO_3( by weight) and 0....The catalytic activity of CoMoS /CNT towards the Egyptian heavy vacuum gas oil hydrotreating was studied. The delivered CNT was functionalized with 6 mol /L HNO_3. The CNT were loaded with 12% MoO_3( by weight) and 0.7 Co /Mo atomic ratio with impregnation methods. The γ-Al_2O_3 catalyst was also prepared by impregnation method to compare both catalysts activities.The analysis tools such XRD,Raman spectroscopy,TEM,and BET were used to characterize the catalysts. The autoclave reactor was used to operate the hydrotreating experiments. The hydrotreating reactions were tested at various operating conditions of temperature 325-375 ℃,pressure 2-6 MPa,time 2-6 h,and catalyst /oil ratio( by weight) of 1 ∶75,1 ∶33 and 1 ∶10. The results revealed that the CoMoS /CNT was highly efficient for the hydrotreating more than the CoMoS /γ-Al_2O_3. Also, the hydrodesulfurization( HDS) increased with increasing catalyst /oil ratio. Additionally,results showed that the optimum condition was temperature 350℃,pressure 4 MPa,catalyst /oil ratio of 1 ∶75 for 2 h. Furthermore,even at low CoMoS /CNT catalyst /oil ratio of 1 ∶75,an acceptable HDS of 77.1% was achieved.展开更多
Surfactants are used for formulation metal working fluids. These fluids are applied to the interface between a cutting tool and the metal working piece to provide friction reduction. In the present paper, poly aromati...Surfactants are used for formulation metal working fluids. These fluids are applied to the interface between a cutting tool and the metal working piece to provide friction reduction. In the present paper, poly aromatic ammonium sulphonate and polyaromatic benzyl triethanolamsonium ethoxylate with 6 ethylene oxide units were synthesized and blended with coupling agent like dodecyl alcohol and oleic acid to produce cutting fluid and evaluate as antiwear. Values of surface tension of these additives were measured in oil phase and consequently CMC was determined for all additives and their mixtures in oil phase. The efficiency of these additives depends on their chemical structure and the presence of ether oxygen brings about the association of the surfactant with metal surface, hence very good wetting properties. The antiwear characteristic of surfactants increases with increasing polar linkages in the aromatic moieties forming chelated and coordinated layer. This is due to the increase in the number of sites to chemisorption on the metal surface. The films formed are highly condensed ring aromatic layered structures. These films provide lower wear and depend on the type of surfactants concentration and sliding speed. The surface of metal was analyzed by SEM/EDX techniques. These studies have led to much clear evidence of the intimate relationship between the chemical structure of the surfactants and their film forming. More confirmation for suggested mechanism was investigated by measuring the area occupied per molecule of the surfactant in oil phase. The results indicate that the sulphonate group is less efficient than ethoxylate group. At the same time, the micelle of surfactants acts as oil dispersant and improves adsorption of oil on the metal surface.展开更多
The porosity of a rock is one of the most important reservoir properties. It controls the reservoir storage capacity. In other words, porosity quantifies the amount of fluids that the rock can store. Most of the world...The porosity of a rock is one of the most important reservoir properties. It controls the reservoir storage capacity. In other words, porosity quantifies the amount of fluids that the rock can store. Most of the world＇s giant fields produce hydrocarbons from carbonate reservoirs. Carbonate rocks contain more than 50% of the world＇s hydrocarbon reserves. Porosity and compressional wave velocity of 41 carbonate samples were determined under ambient conditions in laboratory. The samples were collected from seven shallow wells in west Tushka area, south Western Desert, Egypt. This paper evaluates the well known Wyllie and Raymer equations, an empirical linear equation, and a generalized model for porosity estimation from compressional wave velocity of saturated carbonate samples. Based on the comparison of the predicting identified to provide the most reliable porosity estimation. qualities, the Raymer equation and the empirical linear equation were展开更多
Petroleum hydrocarbons of surface water were collected from eight loca-tions of from the coasts of north western Suez Gulf,Egypt.The extracted petroleum hydrocarbons were determined by gas chromatography-flame ionizat...Petroleum hydrocarbons of surface water were collected from eight loca-tions of from the coasts of north western Suez Gulf,Egypt.The extracted petroleum hydrocarbons were determined by gas chromatography-flame ionization detector and quantified by integrating the areas of both the resolved and unresolved components.The results confirm that the con-centration is relatively higher than the recommended in the regulations of the Egyptian low of Environment of No.4/1994 of petroleum products.At various locations.The dissolved petroleum hydrocarbons ranged from 5.639 to 74.8 and 1.868 to 65.698 mg/ml for summer and winter sea-sons,respectively.This indicates that chronic oil pollution,in addition to hydrocarbon concentrations,the diagnostic indices used shows that the hydrocarbons in the area were comes from biogenic,petrogenic and anthropogenic sources.FT-IR spectrometric analysis confirms die petro-genic nature of pollutants.展开更多
The most prestigious catalyst applied in natural gas （methane） non-oxidative conversion to petrochemicals is 6%Mo/H-ZSM-5. Chromium, molybdenum and tungsten are the group VI metals. Hence, in this work, 6%Mo/H-ZSM-5...The most prestigious catalyst applied in natural gas （methane） non-oxidative conversion to petrochemicals is 6%Mo/H-ZSM-5. Chromium, molybdenum and tungsten are the group VI metals. Hence, in this work, 6%Mo/H-ZSM-5 was correlated with 3%Cr＋3%Mo/H-ZSM-5 and 3%W＋3%Mo/H-ZSM-5 as catalysts to examine their promoting or inhibiting effects on the various reactions taking place during methane conversion. The catalytic activities of these catalysts were tested in a continuous flow fixed bed reactor at 700℃ and a GHSV of 1500 ml·g^-1·h^-1 Characterization of the catalysts using XRD, TGA and TPD were investigated. XRD and NH3-TPD showed greater interaction between the W-phase and the Bronsted acid sites in the channels of the zeolite than between Cr-phase and the acid sites in the zeolite.展开更多
Toluene was alkylated with methanol in a flow type reactor at temperatures between 300 and 500 °C using H-ZSM-5 zeolite, 0.2%Pt/H-ZSM-5 and hydrofluorinated 0.2%Pt/H-ZSM-5 with HF concentrations of 1.0%, 2.0%, 3....Toluene was alkylated with methanol in a flow type reactor at temperatures between 300 and 500 °C using H-ZSM-5 zeolite, 0.2%Pt/H-ZSM-5 and hydrofluorinated 0.2%Pt/H-ZSM-5 with HF concentrations of 1.0%, 2.0%, 3.0%, or 4.0%. Pt primarily enhances toluene conversion, total xylenes production, and p-xylene relative to its thermodynamic equilibrium. As the concentration of HF increases from 1.0% to 3.0%, the catalyst activity increases because of the increase in the number of acid sites and their strength. Additionally, the surface area and Pt dispersion also increases. An advantage of increased HF doping is that the formation of voluminous trimethylbenzene (TMB) byproducts is inhibited. However, at a HF concentration of 4.0%, Al and Si are partially leached and then deposited mostly in the wider catalytic pores. This was determined by evaluating the pore volume distribution and we determined that reactivity inhibition was ob-viously present and was due to diffusion restriction.展开更多
Some polarity terms of two groups of nitrogen-containing surfactants （six alkanolamides and nine polyoxyethylenated long chain amines） are measured through gas chromatography. The apparent methanol carbon number (CM...Some polarity terms of two groups of nitrogen-containing surfactants （six alkanolamides and nine polyoxyethylenated long chain amines） are measured through gas chromatography. The apparent methanol carbon number (CMeOH) and polarity index （IP） values are determined on the investigated surfactants as stationary phases in packed columns. Similarly, CMeOH and IP values are determined on simulated hydrophobic tail （SHT） models. The obtained results reveal that the introduction of SHT approach permits the distinction between the polarities of different surfactants and their head groups. The measured polarity terms are discussed as related to hydrophile-lipophile balance （HLB） number and the hydrophobic group carbon number （RCN）. Some equations relating the measured polarity values and these variable have been developed.展开更多
The Flory-Huggins interaction parameter(χ1,2∞) and solubility parameter(δ2) and its hydrogen bonding sensing component(δh) were determined using inverse gas chromatography(IGC).These parameters were successfully u...The Flory-Huggins interaction parameter(χ1,2∞) and solubility parameter(δ2) and its hydrogen bonding sensing component(δh) were determined using inverse gas chromatography(IGC).These parameters were successfully used in the probes of chemical changes that occur during the oxidation of naphthenic and paraffinic base oils in a GC column.Changes in χ1,2∞ values reflect the different types of intermolecular interactions(dispersive,polar,hydrogen bonding) of the given lubricating base oil during oxidation.The obtained results showed that δh component of solubility parameter is the most important parameter for probing the oxidative-chemical changes during the oxidation of given lubricating oils.展开更多
Inverse gas chromatographic technique(IGC) was attempted as a new approach to follow the chem-ical changes that occur during lubricating base oil oxidation.Three groups of the oxidized base oils were pre-pared at diff...Inverse gas chromatographic technique(IGC) was attempted as a new approach to follow the chem-ical changes that occur during lubricating base oil oxidation.Three groups of the oxidized base oils were pre-pared at different oxygen flow rates,periods and temperatures according to IP48method.The corrected reten-tion volumes(VR) were calculated for a series of selected test solutes possessing different functional groups onthe oxidized base oils used as stationary phases.Kovats retention index(I),Flory-Huggins interaction parame-ter(κ1∞,2),and partial molar free energy of solution(ΔGL∞),were calculated for the given test solutes fromtheirVR.The relationships between theIvalues and the oxidation variables were plotted and discussed.Theobtained results were confirmed by potentiometric titration.The study reveals that the magnitudes of variationofI,κ1∞,2orΔG∞Lretention parameters depend on the oxidation degree of the base oil.Large differences be-tween theIvalues permit discrimination between the different oxidation steps.Key words: inverse gas chromatography(IGC);oxidation;lubricating base oil;Kovats retention展开更多
Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velo...Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velocity （GHSV） of 1500 ml·g ^-1·h^-1 at time-on-stream ranging from 5 rain to 4 h using catalysts containing 6.0%Mo/H-ZSM-5 promoted with Pd or Ir metal. The catalysts were characterized by XRD, TPD, and TGA. The addition of Pd or Ir to 6%Mo/H-ZSM-5 catalyst promoted ethylene production but inhibited the cyclization reaction to aromatics owing to the strong interaction between these noble metals and the framework Al species, which were attached to the acid sites during the impregnation process. Coke deposition on the catalysts was found to decrease upon addition of 0.5wt% of Pd or Ir to 6%Mo/H-ZSM-5 catalyst owing to the hydrogenating activity of these metals.展开更多
The chlorinated and fluorinated zeolite catalysts were prepared by the impregnation of zeolites( H-ZSM-5,H-MOR or H-Y) using two halogen precursors( ammonium chloride and ammonium fluoride) in this study. The influenc...The chlorinated and fluorinated zeolite catalysts were prepared by the impregnation of zeolites( H-ZSM-5,H-MOR or H-Y) using two halogen precursors( ammonium chloride and ammonium fluoride) in this study. The influence of ultrasonic irradiation was evaluated for optimizing both halogen precursors for production of dimethylether( DME) via methanol dehydration in a fixed bed reactor. The catalysts were characterized by SEM,XRD,BET and NH3-TPD. The reaction conditions were temperatures from 100 to 300 ℃ and a WHSV = 15. 9 h-1. All halogenated catalysts showhigher catalytic activities at all reaction temperatures studied. However, the halogenated zeolite catalysts prepared under ultrasonic irradiation showhigher performance for DME formation. The chlorinated zeolite catalysts show higher activity and selectivity for DME production than the respective fluorinated versions.展开更多
Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an ...Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an alkaline medium causes a massive amount of energy losses,hindering large-scale production.Exploring efficient and low-cost catalyst candidates for large-scale H_(2) generation becomes a crucial demand.Single-atom catalysts(SACs)demonstrate great promise for enabling efficient alkaline HER catalysis at maximum atom utilization efficiency.In this review,we provide a comprehensive overview of the recent progress in SACs for the HER application in alkaline environments.The fundamentals of alkaline HER are first introduced,followed by a justification of the need to develop SACs.The rational design of the SACs including the inherent element property,coordination environment,SAC morphology,and SAC mass loading are highlighted.To facilitate the development of SACs for alkaline HER,we further propose the remaining challenges and perspectives in this research field.展开更多
Polarity, partition coefficient （K）, methanol carbon number of surfactant ((CMeOH)S), and methanol carbon number of surfactant head group ((CMeOH)HG) are measured on six alkanolamides and five polyoxyethylenated lon...Polarity, partition coefficient （K）, methanol carbon number of surfactant ((CMeOH)S), and methanol carbon number of surfactant head group ((CMeOH)HG) are measured on six alkanolamides and five polyoxyethylenated long chain amines as stationary phases. From the measured methanol carbon numbers, polarity indices, （IP）S and （IP）HG, are calculated. The determined polarity terms are plotted against the head group weight fraction ( fHG ) of the investigated surfactants and several equations have been developed. The study reveals that the molecular structural gap between alkanolamides and polyoxyethylenated long chain amines diminished when HLB numbers of these surfactant classes are plotted against fHG values. Consequently, a general equation relating HLB and fHG is obtained.展开更多
Molybdenum catalysts（15 wt% Mo O3loading） supported on alumina,alumina–magnesia,and alumina–chromia were prepared via impregnation technique and studied for the reaction of methyl-cyclohexane dehydrogenation. The ...Molybdenum catalysts（15 wt% Mo O3loading） supported on alumina,alumina–magnesia,and alumina–chromia were prepared via impregnation technique and studied for the reaction of methyl-cyclohexane dehydrogenation. The catalysts were evaluated by means of FT-IR,XRD,DSC,TPR,and N2adsorption–desorption isotherms. The results clarified that Mo/alumina–magnesia catalyst possesses small crystallite size and high surface area（240 m2/g） and is selective toward the formation of dehydrogenated product（96.5%）. The yield to ring-opening products is higher on Mo/alumina–chromia catalyst due to its higher acidity and larger metal crystals,which favor the ring-opening reaction and lower metallic activity with selectivity toward ringopening products（32%）.展开更多
The Response Surface Methodology (RSM) has been applied to explore the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/γAl2O3 and...The Response Surface Methodology (RSM) has been applied to explore the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/γAl2O3 and Pd/γAl2O3 disc burners were situated in the combustion domain and the experiments were performed under both fuel-rich and fuel-lean conditions at a modified equivalence (fuel/air) ratio (ø) of 0.75 and 0.25 respectively. The thermal structure of these catalytic flames developed over the Pt and Pd disc burners were inspected via measuring the mean temperature profiles in the radial direction at different discrete axial locations along the flames. The RSM considers the effect of the two operating parameters explicitly (r), the radial distance from the center line of the flame, and (x), axial distance along the flame over the disc, on the measured temperature of the flames and finds the predicted maximum temperature and the corresponding process variables. Also the RSM has been employed to elucidate such effects in the three and two dimensions and displays the location of the predicted maximum temperature.展开更多
Mineralogical, geochemical, and textural analyses of the white sandstones （Abu Thora Fm.） of Carboniferous in the Abu Rodeiyim region show that they are fluviomarine, well-sorted, highpurity, and high-grade silica S...Mineralogical, geochemical, and textural analyses of the white sandstones （Abu Thora Fm.） of Carboniferous in the Abu Rodeiyim region show that they are fluviomarine, well-sorted, highpurity, and high-grade silica SiO2 （average 99.56%）. The results indicate that by simple treatment, the white sandstones can reach a high degree of purity, suitable for different industrial purposes （e.g. manufacture of silicon photovoltaic, crystal, and TV screens, art, and domestic and optical glass）.展开更多
Extended use of supported Pt catalysts causes thermal migration of Pt particles to form large agglomerates,thus decreasing the catalytic activity.The combination of Pt with Re protects Pt against migration.In addition...Extended use of supported Pt catalysts causes thermal migration of Pt particles to form large agglomerates,thus decreasing the catalytic activity.The combination of Pt with Re protects Pt against migration.In addition,Cl injection into the reactor assists Pt particles redispersion to prolong catalyst life.In this work,a PtRe/H-ZSM-5 catalyst was treated with either HCl or HF to investigate their role in activating or deactivating the catalyst.The conversion exceeded 90% in the whole temperature range with the PtRe/H-ZSM-5(HCl) catalyst,and its activity for the direct isomerization of cyclohexene to methylcyclopentenes(MCPEs) was the lowest but the activity for the hydrogenation of the MCPEs to methylcyclopentane was the highest.The reactivities of MCPEs and cyclohexadienes on the catalysts were similar because both are dehydrogenation reactions.Benzene production was significantly higher on the hydrochlorinated catalyst than on the other catalysts,and its hydrocracking activity was the lowest,which is a good characteristic for processing catalysts where cracking is undesired.展开更多
The removal of pesticide (ethoprophos) from aqueous solution using a natural biosorbent such as chitosan (CH) prepared from a biopolymer waste obtained from marine industry was studied. The Fourier Transform Infrared ...The removal of pesticide (ethoprophos) from aqueous solution using a natural biosorbent such as chitosan (CH) prepared from a biopolymer waste obtained from marine industry was studied. The Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-ray diffraction spectroscopy (XRD) were used to study the structure of the adsorbent. The biosorption studies were carried out under various parameters, such as biosorbent dose, initial pesticide concentration and contact time. The experimental results show that the removal percentage of ethoprophos increased from 85.693% to 89.234%, as adsorbent dose (CH) increased from 0.02 to 0.1 g/100ml. The equilibrium uptake was increased with an increase in the initial pesticide concentration in solution. Biosorption kinetic data were fitted well with the pseudo-second order kinetic model. The experimental isotherms data were analyzed using Freundlich, Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm equations. The best fit was obtained by Freundlich isotherm with high correlation coefficients. That the value of energy calculated from the D-R isotherm was 5.56 KJ/mol suggests the adsorption of ethoprophos on Chitosan is physical. All the results indicating CH was chosen as low-cost biosorbent could be applied for the removal of organophosphorous pesticide from aqueous solutions.展开更多
文摘The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected against corrosion by coating. The protective value of a coating system is proportional to the surface preparation;the objectives of the surface preparation are the surface cleanliness and the surface profile of the substrate. The surface preparation is usually achieved by blast cleaning using different types of abrasive. Due to its high hardness and low cost, silica sand has been used extensively for impact abrasion. It is, however, very brittle with most grain disintegrating on impact, causing excessive levels of siliceous dust which is a major health hazard and causes serious environmental pollution. Consequently, it has been banned as impact abrasive material in most countries around the world. Considerable research has been done in the last twenty years to find an impact abrasive material as hard as silica and that respects. So it was important to search for sand substitution among the local abundant minerals in Egypt. Waste product obtained from ilmenite ore extracted from the mine was found to be the most suitable alternative abrasive. This work shows the abrasive types, the occurrence of the ilmenite ore. The chemical properties, physical properties and microscopic examination of the waste were investigated. The obtained result indicates that, the waste product obtained from ilmenite ore can be utilized for abrasion as sand substitution.
文摘The catalytic activity of CoMoS /CNT towards the Egyptian heavy vacuum gas oil hydrotreating was studied. The delivered CNT was functionalized with 6 mol /L HNO_3. The CNT were loaded with 12% MoO_3( by weight) and 0.7 Co /Mo atomic ratio with impregnation methods. The γ-Al_2O_3 catalyst was also prepared by impregnation method to compare both catalysts activities.The analysis tools such XRD,Raman spectroscopy,TEM,and BET were used to characterize the catalysts. The autoclave reactor was used to operate the hydrotreating experiments. The hydrotreating reactions were tested at various operating conditions of temperature 325-375 ℃,pressure 2-6 MPa,time 2-6 h,and catalyst /oil ratio( by weight) of 1 ∶75,1 ∶33 and 1 ∶10. The results revealed that the CoMoS /CNT was highly efficient for the hydrotreating more than the CoMoS /γ-Al_2O_3. Also, the hydrodesulfurization( HDS) increased with increasing catalyst /oil ratio. Additionally,results showed that the optimum condition was temperature 350℃,pressure 4 MPa,catalyst /oil ratio of 1 ∶75 for 2 h. Furthermore,even at low CoMoS /CNT catalyst /oil ratio of 1 ∶75,an acceptable HDS of 77.1% was achieved.
文摘Surfactants are used for formulation metal working fluids. These fluids are applied to the interface between a cutting tool and the metal working piece to provide friction reduction. In the present paper, poly aromatic ammonium sulphonate and polyaromatic benzyl triethanolamsonium ethoxylate with 6 ethylene oxide units were synthesized and blended with coupling agent like dodecyl alcohol and oleic acid to produce cutting fluid and evaluate as antiwear. Values of surface tension of these additives were measured in oil phase and consequently CMC was determined for all additives and their mixtures in oil phase. The efficiency of these additives depends on their chemical structure and the presence of ether oxygen brings about the association of the surfactant with metal surface, hence very good wetting properties. The antiwear characteristic of surfactants increases with increasing polar linkages in the aromatic moieties forming chelated and coordinated layer. This is due to the increase in the number of sites to chemisorption on the metal surface. The films formed are highly condensed ring aromatic layered structures. These films provide lower wear and depend on the type of surfactants concentration and sliding speed. The surface of metal was analyzed by SEM/EDX techniques. These studies have led to much clear evidence of the intimate relationship between the chemical structure of the surfactants and their film forming. More confirmation for suggested mechanism was investigated by measuring the area occupied per molecule of the surfactant in oil phase. The results indicate that the sulphonate group is less efficient than ethoxylate group. At the same time, the micelle of surfactants acts as oil dispersant and improves adsorption of oil on the metal surface.
文摘The porosity of a rock is one of the most important reservoir properties. It controls the reservoir storage capacity. In other words, porosity quantifies the amount of fluids that the rock can store. Most of the world＇s giant fields produce hydrocarbons from carbonate reservoirs. Carbonate rocks contain more than 50% of the world＇s hydrocarbon reserves. Porosity and compressional wave velocity of 41 carbonate samples were determined under ambient conditions in laboratory. The samples were collected from seven shallow wells in west Tushka area, south Western Desert, Egypt. This paper evaluates the well known Wyllie and Raymer equations, an empirical linear equation, and a generalized model for porosity estimation from compressional wave velocity of saturated carbonate samples. Based on the comparison of the predicting identified to provide the most reliable porosity estimation. qualities, the Raymer equation and the empirical linear equation were
文摘Petroleum hydrocarbons of surface water were collected from eight loca-tions of from the coasts of north western Suez Gulf,Egypt.The extracted petroleum hydrocarbons were determined by gas chromatography-flame ionization detector and quantified by integrating the areas of both the resolved and unresolved components.The results confirm that the con-centration is relatively higher than the recommended in the regulations of the Egyptian low of Environment of No.4/1994 of petroleum products.At various locations.The dissolved petroleum hydrocarbons ranged from 5.639 to 74.8 and 1.868 to 65.698 mg/ml for summer and winter sea-sons,respectively.This indicates that chronic oil pollution,in addition to hydrocarbon concentrations,the diagnostic indices used shows that the hydrocarbons in the area were comes from biogenic,petrogenic and anthropogenic sources.FT-IR spectrometric analysis confirms die petro-genic nature of pollutants.
文摘The most prestigious catalyst applied in natural gas （methane） non-oxidative conversion to petrochemicals is 6%Mo/H-ZSM-5. Chromium, molybdenum and tungsten are the group VI metals. Hence, in this work, 6%Mo/H-ZSM-5 was correlated with 3%Cr＋3%Mo/H-ZSM-5 and 3%W＋3%Mo/H-ZSM-5 as catalysts to examine their promoting or inhibiting effects on the various reactions taking place during methane conversion. The catalytic activities of these catalysts were tested in a continuous flow fixed bed reactor at 700℃ and a GHSV of 1500 ml·g^-1·h^-1 Characterization of the catalysts using XRD, TGA and TPD were investigated. XRD and NH3-TPD showed greater interaction between the W-phase and the Bronsted acid sites in the channels of the zeolite than between Cr-phase and the acid sites in the zeolite.
文摘Toluene was alkylated with methanol in a flow type reactor at temperatures between 300 and 500 °C using H-ZSM-5 zeolite, 0.2%Pt/H-ZSM-5 and hydrofluorinated 0.2%Pt/H-ZSM-5 with HF concentrations of 1.0%, 2.0%, 3.0%, or 4.0%. Pt primarily enhances toluene conversion, total xylenes production, and p-xylene relative to its thermodynamic equilibrium. As the concentration of HF increases from 1.0% to 3.0%, the catalyst activity increases because of the increase in the number of acid sites and their strength. Additionally, the surface area and Pt dispersion also increases. An advantage of increased HF doping is that the formation of voluminous trimethylbenzene (TMB) byproducts is inhibited. However, at a HF concentration of 4.0%, Al and Si are partially leached and then deposited mostly in the wider catalytic pores. This was determined by evaluating the pore volume distribution and we determined that reactivity inhibition was ob-viously present and was due to diffusion restriction.
文摘Some polarity terms of two groups of nitrogen-containing surfactants （six alkanolamides and nine polyoxyethylenated long chain amines） are measured through gas chromatography. The apparent methanol carbon number (CMeOH) and polarity index （IP） values are determined on the investigated surfactants as stationary phases in packed columns. Similarly, CMeOH and IP values are determined on simulated hydrophobic tail （SHT） models. The obtained results reveal that the introduction of SHT approach permits the distinction between the polarities of different surfactants and their head groups. The measured polarity terms are discussed as related to hydrophile-lipophile balance （HLB） number and the hydrophobic group carbon number （RCN）. Some equations relating the measured polarity values and these variable have been developed.
文摘The Flory-Huggins interaction parameter(χ1,2∞) and solubility parameter(δ2) and its hydrogen bonding sensing component(δh) were determined using inverse gas chromatography(IGC).These parameters were successfully used in the probes of chemical changes that occur during the oxidation of naphthenic and paraffinic base oils in a GC column.Changes in χ1,2∞ values reflect the different types of intermolecular interactions(dispersive,polar,hydrogen bonding) of the given lubricating base oil during oxidation.The obtained results showed that δh component of solubility parameter is the most important parameter for probing the oxidative-chemical changes during the oxidation of given lubricating oils.
文摘Inverse gas chromatographic technique(IGC) was attempted as a new approach to follow the chem-ical changes that occur during lubricating base oil oxidation.Three groups of the oxidized base oils were pre-pared at different oxygen flow rates,periods and temperatures according to IP48method.The corrected reten-tion volumes(VR) were calculated for a series of selected test solutes possessing different functional groups onthe oxidized base oils used as stationary phases.Kovats retention index(I),Flory-Huggins interaction parame-ter(κ1∞,2),and partial molar free energy of solution(ΔGL∞),were calculated for the given test solutes fromtheirVR.The relationships between theIvalues and the oxidation variables were plotted and discussed.Theobtained results were confirmed by potentiometric titration.The study reveals that the magnitudes of variationofI,κ1∞,2orΔG∞Lretention parameters depend on the oxidation degree of the base oil.Large differences be-tween theIvalues permit discrimination between the different oxidation steps.Key words: inverse gas chromatography(IGC);oxidation;lubricating base oil;Kovats retention
文摘Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velocity （GHSV） of 1500 ml·g ^-1·h^-1 at time-on-stream ranging from 5 rain to 4 h using catalysts containing 6.0%Mo/H-ZSM-5 promoted with Pd or Ir metal. The catalysts were characterized by XRD, TPD, and TGA. The addition of Pd or Ir to 6%Mo/H-ZSM-5 catalyst promoted ethylene production but inhibited the cyclization reaction to aromatics owing to the strong interaction between these noble metals and the framework Al species, which were attached to the acid sites during the impregnation process. Coke deposition on the catalysts was found to decrease upon addition of 0.5wt% of Pd or Ir to 6%Mo/H-ZSM-5 catalyst owing to the hydrogenating activity of these metals.
文摘The chlorinated and fluorinated zeolite catalysts were prepared by the impregnation of zeolites( H-ZSM-5,H-MOR or H-Y) using two halogen precursors( ammonium chloride and ammonium fluoride) in this study. The influence of ultrasonic irradiation was evaluated for optimizing both halogen precursors for production of dimethylether( DME) via methanol dehydration in a fixed bed reactor. The catalysts were characterized by SEM,XRD,BET and NH3-TPD. The reaction conditions were temperatures from 100 to 300 ℃ and a WHSV = 15. 9 h-1. All halogenated catalysts showhigher catalytic activities at all reaction temperatures studied. However, the halogenated zeolite catalysts prepared under ultrasonic irradiation showhigher performance for DME formation. The chlorinated zeolite catalysts show higher activity and selectivity for DME production than the respective fluorinated versions.
基金This work was sup-ported by the Australian Research Council Discovery Projects(Grant Nos.ARC DP200103332 and ARC DP200103315)。
文摘Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an alkaline medium causes a massive amount of energy losses,hindering large-scale production.Exploring efficient and low-cost catalyst candidates for large-scale H_(2) generation becomes a crucial demand.Single-atom catalysts(SACs)demonstrate great promise for enabling efficient alkaline HER catalysis at maximum atom utilization efficiency.In this review,we provide a comprehensive overview of the recent progress in SACs for the HER application in alkaline environments.The fundamentals of alkaline HER are first introduced,followed by a justification of the need to develop SACs.The rational design of the SACs including the inherent element property,coordination environment,SAC morphology,and SAC mass loading are highlighted.To facilitate the development of SACs for alkaline HER,we further propose the remaining challenges and perspectives in this research field.
文摘Polarity, partition coefficient （K）, methanol carbon number of surfactant ((CMeOH)S), and methanol carbon number of surfactant head group ((CMeOH)HG) are measured on six alkanolamides and five polyoxyethylenated long chain amines as stationary phases. From the measured methanol carbon numbers, polarity indices, （IP）S and （IP）HG, are calculated. The determined polarity terms are plotted against the head group weight fraction ( fHG ) of the investigated surfactants and several equations have been developed. The study reveals that the molecular structural gap between alkanolamides and polyoxyethylenated long chain amines diminished when HLB numbers of these surfactant classes are plotted against fHG values. Consequently, a general equation relating HLB and fHG is obtained.
文摘Molybdenum catalysts（15 wt% Mo O3loading） supported on alumina,alumina–magnesia,and alumina–chromia were prepared via impregnation technique and studied for the reaction of methyl-cyclohexane dehydrogenation. The catalysts were evaluated by means of FT-IR,XRD,DSC,TPR,and N2adsorption–desorption isotherms. The results clarified that Mo/alumina–magnesia catalyst possesses small crystallite size and high surface area（240 m2/g） and is selective toward the formation of dehydrogenated product（96.5%）. The yield to ring-opening products is higher on Mo/alumina–chromia catalyst due to its higher acidity and larger metal crystals,which favor the ring-opening reaction and lower metallic activity with selectivity toward ringopening products（32%）.
文摘The Response Surface Methodology (RSM) has been applied to explore the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/γAl2O3 and Pd/γAl2O3 disc burners were situated in the combustion domain and the experiments were performed under both fuel-rich and fuel-lean conditions at a modified equivalence (fuel/air) ratio (ø) of 0.75 and 0.25 respectively. The thermal structure of these catalytic flames developed over the Pt and Pd disc burners were inspected via measuring the mean temperature profiles in the radial direction at different discrete axial locations along the flames. The RSM considers the effect of the two operating parameters explicitly (r), the radial distance from the center line of the flame, and (x), axial distance along the flame over the disc, on the measured temperature of the flames and finds the predicted maximum temperature and the corresponding process variables. Also the RSM has been employed to elucidate such effects in the three and two dimensions and displays the location of the predicted maximum temperature.
文摘Mineralogical, geochemical, and textural analyses of the white sandstones （Abu Thora Fm.） of Carboniferous in the Abu Rodeiyim region show that they are fluviomarine, well-sorted, highpurity, and high-grade silica SiO2 （average 99.56%）. The results indicate that by simple treatment, the white sandstones can reach a high degree of purity, suitable for different industrial purposes （e.g. manufacture of silicon photovoltaic, crystal, and TV screens, art, and domestic and optical glass）.
文摘Extended use of supported Pt catalysts causes thermal migration of Pt particles to form large agglomerates,thus decreasing the catalytic activity.The combination of Pt with Re protects Pt against migration.In addition,Cl injection into the reactor assists Pt particles redispersion to prolong catalyst life.In this work,a PtRe/H-ZSM-5 catalyst was treated with either HCl or HF to investigate their role in activating or deactivating the catalyst.The conversion exceeded 90% in the whole temperature range with the PtRe/H-ZSM-5(HCl) catalyst,and its activity for the direct isomerization of cyclohexene to methylcyclopentenes(MCPEs) was the lowest but the activity for the hydrogenation of the MCPEs to methylcyclopentane was the highest.The reactivities of MCPEs and cyclohexadienes on the catalysts were similar because both are dehydrogenation reactions.Benzene production was significantly higher on the hydrochlorinated catalyst than on the other catalysts,and its hydrocracking activity was the lowest,which is a good characteristic for processing catalysts where cracking is undesired.
文摘The removal of pesticide (ethoprophos) from aqueous solution using a natural biosorbent such as chitosan (CH) prepared from a biopolymer waste obtained from marine industry was studied. The Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-ray diffraction spectroscopy (XRD) were used to study the structure of the adsorbent. The biosorption studies were carried out under various parameters, such as biosorbent dose, initial pesticide concentration and contact time. The experimental results show that the removal percentage of ethoprophos increased from 85.693% to 89.234%, as adsorbent dose (CH) increased from 0.02 to 0.1 g/100ml. The equilibrium uptake was increased with an increase in the initial pesticide concentration in solution. Biosorption kinetic data were fitted well with the pseudo-second order kinetic model. The experimental isotherms data were analyzed using Freundlich, Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm equations. The best fit was obtained by Freundlich isotherm with high correlation coefficients. That the value of energy calculated from the D-R isotherm was 5.56 KJ/mol suggests the adsorption of ethoprophos on Chitosan is physical. All the results indicating CH was chosen as low-cost biosorbent could be applied for the removal of organophosphorous pesticide from aqueous solutions.
