Modeling of the Fischer–Tropsch process using a Fe–Cu–K catalyst

In a bid to increase Fischer–Tropsch product selectivity, inorganics substances, such as copper, potassium, and others, were added to the catalyst. Although this approach in Fischer–Tropsch synthesis is very important, it has not been discussed widely. Isothermal product models in this type of synthesis and effective parameters are the same as pressure, while the H₂/CO feed ratio and space velocity have been studied over the spray-dried Fe–Cu–K catalyst by using statistical methods with experimental data. P = 1.0–2.5 MPa, H₂/CO feed ratio = 0.6–2.0, and space velocity = 0.07–0.1 1/h are the range of operating conditions in the spinning basket reactor. The experiment was carried out at a constant temperature of 523 K. The models can predict the reaction's product. Through these the optimal conditions in the reactor models can be determined, while the maximum and minimum amounts of products for oil, wax, and water are obtained under the optimized conditions. The models showed that the interaction between parameters played a key role. The main interactions for products are pressure and space velocity.     

FLUID–FLUID AND SOLID–FLUID INTERFACIAL INTERACTIONS IN PETROLEUM RESERVOIRS

The distribution and flow behavior of crude oil, gas and brine in the porous rock medium of petroleum reservoirs are controlled largely by the interactions occurring at the interfaces within the various fluids and by the interactions between the fluids and the rock surface. With an objective to correlate the macroscopic multiphase flow behavior with fundamental interfacial interactions, the recent developments in the field of fluid–fluid and solid–fluid interactions and their applications in petroleum engineering are presented in this contribution.

A computerized drop shape analysis technique and its application to the measurement of fluid–fluid interfacial tension at elevated pressures and temperatures are discussed. A recently developed technique that is capable of measuring dynamic (advancing and receding) contact angles at realistic conditions encountered in petroleum reservoirs is presented. Its effectiveness in making reproducible and rapid measurements relative to the conventional techniques is demonstrated with several reservoir case studies.

Attempts are made to correlate the interfacial phenomena of adhesion and spreading in solid–liquid–liquid systems with dynamic contact angles as well as to extend the applicability of the critical surface tension concept from the conventional solid-liquid-vapor systems to the rock-oil-brine systems of interest in petroleum engineering. These interfacial concepts have been applied to the practical problems of asphaltene destabilization from crude oils and the effect of temperature on wettability alteration in heavy oil fields. A simple procedure is outlined to enable the estimation of interfacial adhesion forces and to demonstrate the significant role they play relative to the capillary forces in retaining the fluids within the porous rock medium.     

页岩油藏压裂水平井压–闷–采参数优化研究

目前在页岩油藏的多段压裂水平井压–闷–采过程中,缺乏系统完善的水平井压裂参数优化方法,为此,基于动态反演理论,建立了压裂参数优化方法.首先,根据页岩油藏压裂后形成的复杂缝网,采用数值理论和离散裂缝方法,建立了考虑页岩油储层特征和复杂天然裂缝的多段压裂水平井数值模型(EDFM-NM),得到了含离散天然裂缝的油藏压力解及多...     

页岩气储层自吸–水化损伤–离子扩散相关性试验研究

压裂液与页岩气储层接触后，诱发自吸、水化损伤及离子扩散等水岩反应，导致压裂液返排率低、矿化度高，对压裂改造效果与页岩气产出均有显著影响。目前对上述水岩反应已经开展了针对性研究，但自吸、水化损伤及离子扩散同步产生，对三者之间相关性的研究较缺乏，难以准确认识压裂液与页岩的相互作用，不利于压裂优化设计。为此，立足于室内试验手段，明确了不同条件下的页岩自吸、水化损伤及离子扩散规律及影响因素，系统分析了页岩自吸、水化损伤及离子扩散之间的定量相关性以及相互作用机制。研究结果显示：自吸、水化损伤及离子扩散具有同步响应特征，均在自吸前期发展显著，后续逐渐趋于稳定；自吸与水化损伤相互促进，使页岩吸水量增大；随页岩吸水量增大，离子扩散程度加剧，更多盐离子扩散进入压裂液，使压裂液活度降低，减弱页岩自吸与水化程度。研究成果深化了对压裂液与页岩相互作用的认识，为实现页岩气储层高效水力压裂改造提供了理论支撑。     

南海东部荔湾22–1–1超深水井钻井关键技术

荔湾22–1–1超深水井位于南海东部海域,作业水深2 619.35 m,是目前国内作业水深最深的超深水井。针对该井钻井中存在的水深、海底低温、安全密度窗口极窄、浅部地层成岩性差、隔水管及钻柱力学行为复杂等技术难点,采取了周密的钻井工程设计和现场精细化管理,并应用了喷射下导管技术、FLAT-PRO恒流变合成基钻井液、低温早强水泥浆表层套管固井技术、钻井液当量循环密度随钻监测技术等关键技术措施,安全高效地完成了钻井作业,创造了国内外相同水深钻井周期最短纪录,工程质量全优。荔湾22–1–1超深水井的成功标志着我国超深水钻井技术取得重大突破,不但为我国超深水井钻井积累了宝贵的经验,也对国内外超深水钻井技术的发展具有一定的促进和借鉴作用。      

南海莺–琼盆地复杂地层套管–井眼间隙优化

南海莺–琼盆地地质构造复杂,存在高温高压地层,钻井液安全密度窗口窄,为预防下套管作业过程中产生的波动压力可能诱发的井漏、溢流甚至井喷等井下故障,在充分调研南海莺–琼盆地常用井身结构的基础上,建立了下套管过程中井筒内波动压力计算模型,分析了套管–井眼间隙等不同因素对下套管和注水泥过程中环空压力的影响,对套管–井眼间隙进行了优化。该方法在LD10–2–x井进行了应用,该井五开井段的套管–井眼间隙进优化结果为15.00～19.55 mm,其实际的套管–井眼间隙为17.45 mm,在设计的合理间隙范围内,该井套管下入安全,注水泥过程中未发生井漏、溢流等井下故障。这说明可以根据下套管过程中井筒内波动压力和下套管及注水泥过程中的环空压力优化套管–井眼间隙,为南海莺–琼盆地井身结构设计提供依据。      

Enhancement of the Fischer–Tropsch process for producing long-chain hydrocarbons on a cobalt–alumina–silica gel catalyst

The effects of the H₂/CO ratio, pressure, temperature, and the reaction-gas recycle ratio on the selectivity for hydrocarbons (HCs), including long-chain C₃₅₊ HCs, in the Fischer–Tropsch synthesis over a supported industrial cobalt–silica gel catalyst have been studied. The synthesis parameters have been as follows: a pressure of 2.0 or 6.0 MPa, an H₂/CO ratio of 1–5, a recycle ratio of 2–6, a temperature of 150–240°C, and a gas hourly space velocity of 1000 h^?1. It has been shown that gas recycling provides thermal stability in the catalyst bed, significantly increases the yield of C₃₅₊ HCs, and makes it possible to control the group and fractional composition of the synthesis products.     

Study on the characteristics of palm oil–biodiesel–diesel fuel blend

Palm oil/palm oil methyl esters are blends with diesel fuel, the blends were characterized as an alternative fuels for diesel engines. Density, kinematic viscosity, and flash point were estimated according to ASTM as key fuel properties. Palm oil and palm oil biodiesel were blended with diesel. The properties of both blends were estimated. The results showed that the fuel properties of the blends were very close to that of diesel till 30% unless other characteristics are within the limits. The experimental data were correlated as a function of the volume fraction of oil/biodiesel in the blend. Different correlations were developed to predict the properties of the oil/bio-oil-diesel blends based on our experimental results. The developed correlations were validated by comparing the correlation prediction with experimental data in literature. A good agreement was found between modeled equations prediction and experimental data in literature. The developed equations can be used as a guide for determining the best blending mixture to be used for diesel engines.     

N,N–di(polyoxyethylene)–4–dodecylaniline as a corrosion inhibitor for steel in hydrochloric acid solutions

We have used weight loss measurements, potentiodynamic polarization, and lectrochemical impedance spectroscopy to study the inhibiting effect of N,N–di(polyoxyethylene)–4–dodecylaniline, with different numbers of oxyethylene units, on corrosion of steel in a 1 M hydrochloric acid solution. We have determined that the studied compounds are good corrosion inhibitors. The inhibition efficiency increases with an increase in inhibitor concentration, an increase in the number of oxyethylene units in the chain of the inhibitor, and a decrease in temperature. The inhibiting effect of the studied compounds is due to blocking of the metal surface as a result of adsorption of the oxyethylene units of the inhibitor. The adsorption process is described by the Freundlich isotherm. The indicated compounds act as mixed (mostly anodic) corrosion inhibitors. We calculate some thermodynamic corrosion parameters.     

Effect of styrene–butadiene–styrene copolymer modification on properties of Saudi bitumen

This research investigates the effects of styrene-butadiene-styrene (SBS) copolymer and other plastomers on the behavior of Saudi bitumen. Three bitumen samples, extracted from three Saudi oil refineries, namely Ras Tanura, Riyadh, and Yanbu, were used in this study. The bitumen samples were mixed with different modifiers in various compositions, forming polymer modified bitumens (PMBs). Elasticity parameters, such as ductility and elastic recovery were measured and evaluated. Characteristics of raw bitumen were analyzed to observe the compatibility of bitumen with SBS and plastomers. Bitumen samples were suitable for SBS modification and SBS PMBs showed superior elasticity behaviors compared to plastomer blends.     

Dependence of composition of asphaltene–resin–wax deposits on the water cut value

The deposit formation process in water/oil emulsions based on waxy high-resin oils with different amounts of the aqueous phase has been studied. It has been shown that the deposition rate greatly increases with an increase in the relative amount of the aqueous phase. Relationships of the component composition of paraffin hydrocarbons and the structural group composition of asphaltenes in asphaltene–resin–wax deposits with the water content of the emulsions have been revealed.     

The study of catalytic performance of silica-supported three metallic Fe–Co–Ce catalyst prepared using impregnation procedure for Fischer–Tropsch synthesis

We apply the wet impregnation procedure to prepare the Fe–Co–Ce catalyst supported by silica. The effects of operational conditions such as temperature, pressure, and the feed ratios of reaction on the selectivity and yield were studied. The production of light olefins from syngas (CO and H₂) over this catalyst in a fixed bed reactor via Fischer–Tropsch synthesis (FTS) was investigated. The reactor tests were determined through the design experiments.The optimum condition was determined in a way that the selectivity of methane was the least and other olefins have the maximum selectivity. The results indicated that the catalyst at 350°C, 3 bar, and syngas with H₂/CO ratio 1/1 has shown the better catalytic performance for FTS.     

Modelling the multiphase flow of an oil–gas–condensate system in porous media

The “Black oil” model is extended to describe the four-phase flow of the oil-gas–condensate systems in porous media, by considering the solubilities of gas in the condensate, water, and oil phases and condensate evaporation into the gas phase. The three-dimensional transient-state model equations are reduced to one-dimensional transient-state forms by the partial integration method. The finite-difference method is used for solution of this model. The calculations of the hydrodynamical parameters of an oil–gas–condensate reservoir element are carried out for several cases, involving a water table in its natural state of the development, water flooding under water–oil contact, combined state of water flooding under water–oil contact and gas pumping into gas zone of the reservoir. This study provides a comparison of the effect of the different exploitation methods of the reservoir fluids production. The present simulation studies indicate that the combined flooding method yields faster recovery.     

Estimating Sand–Shale Formation Pore Pressure

Abstract

This article presents a comprehensive evaluation method of estimating sand–shale formation pore pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and then pore pressure can be obtained by the effective stress principle. Using this method, software was developed and it applied in the well site. Its applications indicate that this method can accurately estimate the abnormal pressure of a sand–shale formation.     

Naphthalene hydrogenation over nickel–tungsten sulfide catalysts synthesized in situ from DMSO–hydrocarbon medium emulsions

A method for synthesizing unsupported nickel–tungsten sulfide hydrodearomatization catalysts by breaking SPAN-80 surfactant-stabilized nonaqueous emulsions of solutions of different precursors in dimethyl sulfoxide (DMSO) in situ in a hydrocarbon medium has been first studied using ammonium thiotungstate (NH₄)₂WS₄ and 1-butyl-1-methylpiperidinium nickel thiotungstate [BMPip]₂Ni[WS₄]₂ as precursors and nickel nitrate hexahydrate as a nickel source. The synthesized nickel–tungsten catalysts have been characterized by TEM and XPS. The catalytic activity of the in situ synthesized Ni–W particles in naphthalene hydrogenation has been studied at temperatures of 350–400°C and a hydrogen pressure of 5.0 MPa.     

Eduard Feliksovich Kaminskii, 1932–2005

Obituary

Eduard Feliksovich Kaminskii, 1932–2005     

Study of the Catalytic Stability of Dispersed Molybdenum–Tungsten–Nickel Sulfides in Bicyclic Hydrocarbon Hydrogenation Recycles

The possibility of recycling dispersed Mo–W–Ni sulfide catalysts synthesized in situ from metal–polymer precursors in the hydrogenation of bicyclic hydrocarbons is explored. It is found that, with a view to preserving the catalytic activity in recycles, an optimum technology for separating the dispersed catalysts from the reaction mixture is centrifugation. The composition and morphological features of the catalysts isolated in different cycles are determined by TEM, XPS, SEM, and XRD methods.     

A novel La3+–Zn2+–Al3+–MoO42− layered double hydroxides photocatalyst for the decomposition of dibenzothiophene in diesel oil

A new type of photocatalyst, La³⁺-Zn²⁺-Al³⁺-MoO₄^2? layered double hydroxide (LDH) (La:Zn:Al = 1:7:2), was prepared by a complexing agent-assisted homogeneous precipitation technique. The LDHs were used as catalysts for the desulfurization of diesel oil under UV irradiation. As revealed by the results, the catalyst showed superior desulfurization efficiency and recycling performance. Under UV irradiation, the desulfurization efficiency was 84% in 60 min. In La³⁺–Zn²⁺–Al³⁺–MoO₄^2? LDHs, the introduction of MoO₄^2? increased the interlayer space for promoting the adsorption of dibenzothiophene, and MoO₄^2? might act as the active sites for the oxidation of dibenzothiophene, resulting in the high desulfurization efficiency.     

Sensor array for the combined analysis of water–sugar–ethanol mixtures in yeast fermentations by ultrasound

For the sugar fermenting industry, it is important to know the exact concentration values of sugar and ethanol in the process fluid during the alcoholic fermentation as an indicator for the fermentation progress. In this study, an ultrasound-based method for determining the concentration of sugar and ethanol simultaneously is presented. The ultrasound velocity in various binary (water–saccharose, water–ethanol) an ternary (water–saccharose–ethanol) mixtures in dependance of the temperature was measured with a pulse-echo method. The sugar and ethanol fraction in aqueous solutions cause an additive, but nonlinear component to the sound velocity of pure water dependant on the concentration and the temperature. A calibration model for the ultrasound velocity in water–sugar–ethanol mixtures was found by establishing a polynomial approach based on the experimental results. The coefficients of this polynom are obtained with a linear regression method by inserting the measurement points. The derived calibration function is continuous, monotone and relates one value of sound velocity to one certain set of concentration values and temperature unambiguously. By means of these mathematical properties, it can be shown that it is possible to determine the sugar and ethanol concentration values in water–sugar–ethanol mixtures only by measurement of the sound velocity at two different temperatures. The method is evaluated by determining the sugar-, respectively ethanol concentration in standardized water–saccharose–ethanol mixtures and in commercial beer probes with an accuracy of approximately 0.5 g/100 g up to 0.01 g/100 g.     

Dibenzothiophene Hydrodesulfurization Activity of MoS2 Supported in Sol–Gel ZrO2–TiO2 Mixed Oxides

Abstract

In this work, we report the effect of support composition on the properties of MoS₂ impregnated in sol–gel ZrO₂–TiO₂ mixed oxides as dibenzothiophene hydrodesulfurization catalyst. The supports calcined at 500°C were characterized by N₂ physisorption and X-ray diffraction (electronic radial distribution function). The oxidic impregnated materials (2.8 Mo atoms/nm²) were sulfided at 400°C under a H₂S/H₂ stream. The sample impregnated on the equimolar support showed the highest activity per mass of catalysts whereas the one with TiO₂ carrier was superior in a per mass of Mo basis. Marked differences in products selectivity were observed by TiO₂ addition in the supports. The hydrodesulfurization route to partially hydrogenated compounds was favored over the mixed oxides-supported catalysts meanwhile the direct desulfurization (to biphenyl) was promoted on the ZrO₂-supported solid. It is suggested that among other properties the dispersion and morphology of the MoS₂ phase could influence that behavior.