Catalytic cracking of light-naphtha fraction over zeolite-based composites in fixed-bed mode was investigated to establish an efficient method for on-purpose propylene production. The composite catalysts, consisting of MFI-type zeolites containing iron, gallium and aluminum species (Fe–Ga–Al-MFI) and metal-oxide binder (e.g., silicon oxide, aluminum oxide), were employed for cracking of light-naphtha fraction. Fe–Ga–Al-MFI zeolites as matrix, containing each heteroatom at adequate ratio in the zeolite framework, exhibited both overall acid strength suitable for selective formation of light olefins and enhanced activity for dehydrogenation of light alkanes to alkenes, so that high overall yields of light olefins (ethylene, propylene and butenes) were attained by suppressing aromatics formation compared to cracking of light-naphtha fraction using conventional Al-MFI zeolite (ZSM-5). The unique acidity of the Fe–Ga–Al-MFI zeolite was maintained in the extruded form by using neutral and inactive silicon–oxide binder, which was selected to enhance mechanical strength and/or reduce pressure drop during reaction. The zeolite-based composite (Fe–Ga–Al-MFI/SiO2) selectively converted light-naphtha fraction (n-hexane) into light olefins including propylene with catalyst lifetime longer than 2000 h, suitable for fixed-bed operation, due to its excellent resistance to coke formation. Furthermore, the cracking reactions proceeded in the absence of steam at moderate temperatures below 650 °C, so catalytic cracking using the present zeolite-based composite saved considerable thermal energy required in the reaction unit, and the total amount of hydrocarbon feedstock was reduced by ca. 15 %, compared to conventional thermal cracking at 850 °C. The present review discusses the excellent properties of these zeolite-based catalysts and catalytic cracking of light-naphtha fraction emphasizing the catalytic chemistry and reaction engineering of the catalytic process.
Four case studies involving asphaltene precipitation risks in oilfields are used to demonstrate how pitfalls can be minimized by multidisciplinary approach using all available information. Three cases are presented from a gas injection aspect and the fourth from a geochemical aspect under conditions of uneven asphaltene risk distribution. The evaluations show how to practically interpret laboratory-derived information with regard to actual on-site phenomena. Numerical asphaltene fluid models calibrated using measured asphaltene onset pressure (AOP) were generated to evaluate asphaltene precipitation envelopes (APE) by applying the cubic plus association equation of state. Sensitivity analysis based on the numerical model was performed in each study to investigate the impact of development scenario on APE behavior. The case studies cover a range of technical subjects, including injection gas type, gas mixing ratio, fluid dynamics such as the vaporizing gas drive (VGD) process, and local variation of asphaltene contents. These technical subjects pose potential pitfalls that may be hidden from the viewpoint of a single discipline. The results successfully reveal the following insights: (1) risks offset by dry gas can be considered whereas a general understanding is required of gas injection-related risks; (2) VGD-process enrichment of the injection gas should be considered; (3) asphaltene risks can vary with the fluid dynamics timing, such as higher enriched gas accumulation and lower lean gas accumulation near wellbore; (4) a pseudo APE concept can be useful in the absence of experimental AOP data; and (5) oil migration history can be related to asphaltene risk distribution.
In recent years, important breakthroughs have been made in the exploration of the northwestern margin of Mahu sag in Junggar basin. The estimated amount of oil deposits in this region seems to be as large as 100-million-ton lithologic reservoir. A certain scale of oil reservoirs was found in the Jurassic Badaowan formation, which indicates that the Jurassic reservoir has promising prospects for exploration. The geochemical characteristics of Jurassic crude oil and Permian source rocks and oil accumulation factors are studied in this paper. The results show that carbon isotope values (δ13C) and the biomarker parameters (γ/C30H and C24Tet/C26TT) have a good application in oil source correlation. Crude oil in Jurassic reservoir was generated from Permian Fengcheng (P1f) source rock. The main hydrocarbon expulsion period of the P1f source rock was between late Permian and middle Cretaceous. The crude oil migrated upward into the Jurassic lithologic traps through faults or superimposed sand bodies.
We systematically studied the influential factors of post-steam in-situ combustion (ISC) project conducted in complex heavy oil reservoir in China using laboratory one-dimensional combustion experiments, reservoir simulation outputs, and data collected from the field application. The ISC project showed vastly different production performances in different regions of the field and two types of representative factors which acts on the whole ISC production stages were identified. As for a post-steam ISC process, oil viscosity and the pre-ISC recovery factor are the main reservoir parameters affecting the performance of ISC process and numerical model reflecting these two factors were established to analysis the production characteristics of producers. Type I group has a low oil viscosity (<8000 mPa s) and a high steam-flooded recovery factor (>30 %); after ISC treatment, these producers show a high initial water cut, while some experience channeling issues and hence produce a large quantity of flue gas. Type II group has a high oil viscosity (>20,000 mPa s) and a low cyclic steam stimulation (CSS) recovery factor (15-20 %); these producers have a high air injection pressure exceeding the fracture pressure. Results show that corresponding remedial methods applied to these two well groups can effectively enhanced oil recovery.
Alkaline-surfactant-polymer (ASP) flooding is one of the leading technologies successfully applied in enhancement of oil recovery over the last few decades. However, it has suffered from high cost and poor environmental compatibility. In this work, a new pseudo-ternary flooding system containing Na2CO3, lipopeptide biosurfactant, petroleum sulfonate, and partially hydrolyzed polyacrylamide was developed, and its possibility in enhancement of oil recovery was evaluated. Compared with the traditional ASP containing only petroleum sulfonate as the surfactant component, the interfacial tension between the new pseudo-ternary flooding system and Daqing crude oil was reduced to a low level in the order of 10−4 mN/m, implying positive synergistic effects of the biosurfactant, lipopeptide, and petroleum sulfonate in the new B-ASP system. Meanwhile, the thermal adaptability, interfacial activity, and viscosity stability of the new B-ASP system were significantly improved. The results of this study suggest that B-ASP is a promising and cost-effective flooding system and a developing technology for tertiary oil recovery, particularly amid uncertainties pertaining to oil price fluctuations. To the best of our knowledge, this is the first report on a pseudo-ternary flooding system composed of B-ASP for oil recovery.
Boiling point and bubble point pressure in binaries with propane were measured for five compounds, 1-pentyne, cyclopentene, 1-hexyne, 2-hexyne, and 1,5-cyclooctadiene, new sulfur-free odorants for liquefied petroleum gas. The boiling point was measured with an ebulliometer under atmospheric pressure. The experimental boiling points were 313.51, 313.76, 344.53, 357.59 and 424.02 K for 1-pentyne, cyclopentene, 1-hexyne, 2-hexyne, and 1,5-cyclooctadiene, respectively. The bubble point pressures were measured with a static apparatus at 303.15 K. The pressure was also measured by a synthetic apparatus at 303.15 K for propane–1-hexyne. The experimental boiling points were used for estimation of critical temperature, critical pressure and acentric factor by Lydersen’s group contribution method to evaluate the two constants in the Peng-Robinson equation of state. The Peng-Robinson equation could correlate the bubble point pressure to the mole fraction of propane with absolute relative deviation of less than 2.556 %. The data will be useful in the development of fuel cells with reformers for liquefied petroleum gas.
Highly dispersed SrO in amorphous Al2O3, SrO–Al2O3, was synthesized by solid-liquid interface reaction of Sr(OH)2 · 8H2O in the solid phase with Al(OCH(CH3)2)3 dissolved in 2-propanol. The water of crystallization in Sr(OH)2 · 8H2O was consumed for the hydrolysis of Al(OCH(CH3)2)3. SrO–Al2O3 catalyst synthesized by solid-liquid interface reaction of equimolar amounts of Sr(OH)2 · 8H2O and Al(OCH(CH3)2)3, then heat treated at 673 K, exhibited the highest activity among the prepared catalysts for the base-catalyzed retro-aldol reaction of diacetone alcohol. Catalytic activity of SrO–Al2O3 catalyst calcined at 673 K was twice that of SrO–Al2O3 catalyst prepared by physical mixing of Sr(OH)2 · 8H2O with Al2O3. Active SrO–Al2O3 catalyst was obtained by heating at a temperature just below that of Sr3Al2O6 crystallization. Formation of SrO by heat treatment at 673 K was confirmed using X-ray absorption near edge structure analysis. The SrO particle size was too small for detection by powder X-ray diffraction. We found that interface reaction of a metal hydroxide in the solid phase with an alkoxide in the liquid phase is useful for the preparation of well-dispersed mixed metal oxides under mild conditions.