Combination of hydrotreating and delayed coking technologies for conversion of residue

Residue conversion by combining catalytic hydrotreating and delayed coking has been evaluated comparatively with both processes alone.Optimal operating conditions are defined to achieve the greatest economic benefit for upgrading an atmospheric residue from a heavy crude oil.A literature model was adapted to simulate the hydrotreating reactor,and for delayed coking,correlations reported in the literature were used.The results with both approaches were employed to calculate the techno-economic feasibility of the combined process scheme.The combination of hydrotreating and delayed coking presented an increase in light fractions of 29% and a reduction in coke production of 47.8%.Based on the calculated net benefit values,it was demonstrated that the combination of hydrotreating and delayed coking is technically and economically better than using each process alone,with highest benefit of 57.7 USD·m^(-3).

断裂长度与最大位移的关系及其影响因素(英文)

断裂最大位移与断裂迹长遵循幂律关系 :D =cLn,但幂指数n的大小有很大的变化范围。为探索幂指数n的大小和断裂机制 ,从已发表的文献中收集了 18组数据 ,这些数据的断裂长度具有 8个数量级的跨度。经相关分析 ,我们得到n值的大小变化于 0 5 5和 1 6 5之间 ,平均值为 1 0 839。由于走滑断裂的最大长度在其倾向方向 ,不宜与倾滑断裂一起统计 ,我们去掉一组走向滑动断裂的数据 ,幂指数平均值为 1 10 6 6。用双回归方法得到的幂指数峰值 (nd)是 1 0～ 1 1。这些结果表明断裂最大位移与断裂迹长应该是非常接近线性关系。这种线性关系可以用Dugdale模型加以解释。该模型认为弹塑性物质拉张裂缝端点的变形是非弹性变形。模型的适用范围是单一岩性 ,一次构造力作用。我们认为n值的大小之所以有很大的变化范围 ,有可能受到断裂迹线长度偏差的影响 ,造成长度偏差的因素包括 :不同的观察平面 ,断裂端点的分辨率 ,断裂连接作用 ,岩石力学性质变化 ,断裂多期活动等。

Hydrodeoxygenation of vegetable oil in batch reactor:Experimental considerations

The generation of reliable experimental data in any experimental scale requires proper procedures not only for the reaction step but also for the feed preparation,separation,and characterization of products as well as calculations of conversion and product yields.Batch reactor is the most used experimental setup for carrying out exploratory studies for catalyst screening and development.This work is focused on describing and discussing a step-by-step methodology for conducting experiments for catalytic hydrotreating of vegetable oils in batch reactor.The proposed methodology considers literature and own experiences on advantages and disadvantages of different feed types,catalysts,experimental setup and procedures,effect of reaction parameters,separation and characterization of products,and calculations.

Sulfide Stress Cracking Assessment of Carbon Steel Welding with High Content of H<SUB>2</SUB>S and CO<SUB>2</SUB>at High Temperature: A Case Study

In the oil and gas industry, it has been established that for pipelines fabricated with carbon steels, their limitation is related to H2S and CO2 environments, which is 7 to 10 psia of partial pressure of CO2. Therefore, in carbon steel cracking is shown, after 7 or 10 psia of partial pressure of CO2. The experimental work was performed under static conditions in autoclaves within a pH of 3 to 3.8;partial pressures of 16 - 96 psi for H2S and 15 - 53 psi for CO2, in the temperature range of 25°C - 150°C. It was observed that the average yielding stress used in Sulfide Stress Cracking (SSC) tests decreases with temperature increment. Hydrogen Induced Cracking (HIC) evaluations showed that X52 steel, under conditions, was not susceptible to HIC. Results of SSC did not show indications of cracking after exposure to sour solutions, except for the specimen exposed to high H2S and CO2 content (96 psi of H2S and 53 psi of CO2 of the partial pressure) and high temperature (150°C). Microcracks located between the upper and lower weld beads were also observed. However, the highest average corrosion rate was 0.27 mm/year (10.6 mpy), which occurred in samples exposed to 96 psi of H2S and 53 psi of CO2 at 150°C. Likewise, the highest localized corrosion (severe pitting attack) was obtained at the same environment with a corrosion rate of 4.2 mm/year (167 mpy). The oil and gas industry could use carbon steels pipelines in partial pressure higher than 10 psia.

Upgrading of Heavy Crude Oil with W-Zr Catalyst

The main problem of new crude oil reserves is the incipient increase of heavy crude oils in the American continent, i.e. USA, Mexico, Canada and Venezuela. These types of crude oils require several treatments before refining. One of these treatments can be hydrocracking. In this petroleum refining process, it is possible to modify the heavy crude oils to light crude oils. In this paper, we try to use hydrocracking to improve the quality of raw heavy crude oil, through some chemical transformations C-H binding rupture using a catalyst containing active metals such as tungsten and zirconium (W-Zr). After the crude oil was hydrocracked in presence of this novel bimetallic catalyst, the hydrocracked products showed lower content of asphaltenes, resins, sulfur and nitrogen. Also positive changes in the viscosity of crude oil measured as a decreasing of this value were observed. The American Petroleum Institute (API) gravity was significantly increased 6 units. Consequently, all these changes confirmed that the upgrading of the heavy crude oil was successful.

Evaluation of Stress Corrosion Cracking Damage to an API 5L X52 Pipeline Transporting Ammonia: A Case Study

The high number of leak events that took place in recent years at a 25.4 cm (10”)&Oslash;pipeline transporting anhydrous liquid ammonia, located in the Southeast of Mexico, was the main reason to carry out a number of field studies and laboratory tests that helped establish not only the failure causes but also mitigation and control solutions. The performed activities included direct evaluation at failure sites, total repair programs, metallographic studies and pipeline flexibility analyses. The obtained results were useful to conclude that the failures obeyed a cracking mechanism by Stress Corrosion Cracking (SCC) which was caused by the combined effect of different factors: high stress resistance, high hardness of the base metal with a microstructure prone to brittleness and residual strains originated during the pipeline construction. From the operative, logistic and financial standpoints, it is not feasible to release the stress of approximately 22 km of pipeline. Therefore, the only viable solution is to install a new pipeline with suitable fabrication, construction and installation specifications aimed at preventing the SCC phenomenon.

Ozone forming potential and sulfur effects on in-use vehicles of the metropolitan area of Mexico City

The largest urban areas of Mexico cities have witnessed high levels of air pollution in the past few decades. The most important air pollutants are ozone and paniculate matter with levels that are still far above current air quality standard. In this work we studied exhaust and evaporative emissions of Mexico City metropolitan area （MAMC） vehicles using fuels in which sulfur content was varied from 89×10^-6 to 817×10^-6, and calculated the ozone forming potential of emissions as well as the specific reactivity of the exhaust for each average fleet-fuel combinations. Data on emission levels were compared to those obtained in 2000 for the same vintage of vehicles. The almost twofold increase in emissions found could be due to degradation of the exhaust emissions control systems.

Hybrid low salinity water and surfactant process for enhancing heavy oil recovery

Combining low salinity water (LSW) with surfactants has an enormous potential for enhancing oil recovery processes. However, there is no consensus about the mechanisms involved, in addition to the fact that several studies have been conducted in model systems, while experiments with rocks and reservoir fluids are scarce. This study presents a core-flooding experiment of LSW injection, with and without surfactant, using the core and heavy oil samples obtained from a sandstone reservoir in southeastern Mexico. The effluents and the crude oil obtained at each stage were analyzed. The study was complemented by tomographic analysis. The results revealed that LSW injection and hybrid process with surfactants obtained an increase of 11.4 percentage points in recovery factor. Various phenomena were caused by LSW flooding, such as changes in wettability and pH, ion exchange, mineral dissolution, detachment of fines and modification of the hydrocarbon profile. In the surfactant flooding, the reduction of interfacial tension and alteration of wettability were the main mechanisms involved. The findings of this work also showed that the conditions believed to be necessary for enhanced oil recovery with LSW, such as the presence of kaolinite or high acid number oil, are not relevant.

低矿化度水与表面活性剂混注提高稠油采收率机理

针对低矿化度水与表面活性剂混注工艺提高原油采收率机理不清的问题,采用墨西哥东南部砂岩油藏储集层岩心和稠油样品,开展了加入表面活性剂和未加入表面活性剂条件下的低矿化度水岩心驱替实验,并结合层析分析方法,研究驱替过程中岩心内部的变化。结果显示,低矿化度水和表面活性剂混注工艺能够提高采收率,实验中低矿化度水驱与混注工艺提高岩心采收率11.4个百分点。低矿化度水驱使得岩心中产生多种现象,例如润湿性改变、pH值变化、离子交换、矿物溶解、微粒运移和原油组分变化等。在表面活性剂驱替过程中,界面张力降低和润湿性改变是提高采收率的主要机理。以往研究认为低矿化度水驱提高原油采收率需要储集层中存在高岭石或原油为高酸值原油,但驱替实验结果表明这两点并非必要条件。

Electrochemical nucleation and growth of aluminum nanoparticles and leaf-like flat microstructures from reline deep eutectic solvent: Effect of temperature and angular speed of working electrode

The main objective of this work was to use reline deep eutectic solvent,containing Al(III)ions,for the electrochemical study of the nucleation and growth of aluminum onto a glassy carbon electrode at different temperatures and angular speeds(ω)of the working electrode.In order to fulfill this,electrochemical and surface characterization techniques were used.It was found that as temperature increased,the onset of the Al(III)DES reduction occurred at less negative potentials while the current peak of the voltammograms increased.These indicate that Al deposition thermodynamics and kinetics were favored.Practically,no anodic current was detected due to Al passivation by Al(OH)_(3)(s)andγ-Al_(2)O_(3)(s).Atω=0 r/min,the Al deposition chronoamperograms were analyzed by a theoretical model comprising Al 3D diffusion-controlled nucleation and growth and residual water reduction.However,those recorded at different angular speeds were analyzed with a theoretical model where adsorption−desorption and diffusion-controlled nucleation−growth occurred simultaneously.The deposits were characterized by SEM,EDX,XPS and XRD.Atω=0 r/min,formation of well distributed nanoparticles((78.1±9.5)nm)was observed,while atω=900 r/min the deposit was formed by multiple 10μm diameter leaf-like flat microstructures,composed by Al,Al(OH)_(3)(s)andγ-A2O3(s).

Near shore seismic movements induced by seaquakes using the boundary element method

This study quantifies seismic amplifications in near-shore arising from seaquakes. Within the Boundary Element Method, boundary elements are used to irradiate waves and force densities obtained for each element. Huygens′ Principle is implemented since the diffracted waves are constructed at the boundary from which they are radiated, which is equivalent to Somigliana′s theorem. Application of boundary conditions leads to a system of integral equations of the Fredholm type of second kind and zero order. Several numerical configurations are analyzed： The first is used to verify the present formulation with ideal sea floor configurations to estimate seismic amplifications. With the formulation verified, simple slope configurations are studied to estimate spectra of seismic motions. It is found that P-waves can produce seismic amplifications from 1.2 to 3.9 times the amplitude of the incident wave. SV-waves can generate seismic amplifications up to 4.5 times the incident wave. Another relevant finding is that the highest amplifications are at the shore compared to the ones at the sea floor.

Production of Carbon Nanotubes and Hydrogen Catalyzed with Ni/MCM-41 Catalysts

Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate temperature range from 400°C to 600°C and the catalytic activity of the catalysts remains stable during 500 min steam on time. CNTs were chiefly formed through tip-growth mode, due to the weak interaction between the metallic Ni and the support. Most of the Ni particles are located on the tip of the produced CNTs, which avoids rapid deactivation of the catalyst resulted from carbon encapsulation. Large Ni particles usually lead to the formation of CNTs with big diameter. During the reaction, the shape of Ni particles changed from pseudo-sphere to diamond-like. All the CNTs consist of multiple layer walls and are curved in certain degree.

Concept Selection for Hydrocarbon Field Development Planning

Two methodologies to rank exploitation scenarios for hydrocarbon fields during screening and concept selection stages are described and compared. First a selection based on net present value valuation is introduced and an explanation on its limitations for field planning are given thus, a second selection based on a multiattribute decision model where other technical factors not directly associated to economics such as operability and reliability are considered. A comparison of net present value and the multiattribute decision model on a concept selection study case shows differences on the scenario selection for exploitation. Sources of the different outcomes between the two methodologies are identified. A stochastic analysis for the multiattribute decision model is performed to have a complete view of the possible outcomes since the factors in the multiattribute decision model are measured qualitatively and their values can vary depending on experts’ knowledge and experience. Recommendations obtained from the methodologies studied for screening and concept selection are given.

The Adjust Data with the Laboratory PVT Reports that Are Applied in the Oil Wells Designs

The correlations have been developed with the flash data to predict the multiphase flow and mass transfer in the oil wells designs. Therefore, the laboratory pressure/volume/temperature (PVT) reports require calculation of the flash Oil Formation Volume Factor and the flash Solution Gas/Oil Ratio data starting from Differential Liberation tested data. Once these parameters are known, the oil density and other thermophysical properties can be determined by a complete model for the different states of pressure and temperature in the well during its production life and initial design. The subject of this paper is how to read and make proper use of information contained in the IMP laboratory PVT reports, for the oil wells designs. The discussion is focused on the laboratory report for the well number 407 located in the Maloob field in Mexico.

Corrosion of Steel Pipelines Transporting Hydrocarbon Condensed Products, Obtained from a High Pressure Separator System: A Failure Analysis Study

In this paper, the corrosion of steel pipelines transporting hydrocarbon condensed products was studied. Different activities of sampling and analysis were carried out to diagnose the failure causes and to establish a control system for the corrosion problem. The combination of three types of corrosion, including erosion corrosion, galvanic corrosion and microbiologically induced corrosion, was synthetically considered. A serial of experiments were designed to research those types of corrosion. This type of failure was observed in characteristics sites of the pipeline, mainly in direction changes and welding joints. Additionally, localized corrosion was observed in the inner steel wall and distributed along the pipeline, although a tendency was not detected.

Potential Effects on Human Health of Hydrogen Sulfide Exposure in a Place in Southeast of Mexico

Ambient concentrations of H2S were determined by modeling the H2S emissions dispersion for three sites located in the surroundings of oil and gas maritime terminal at the southeast of Mexico. Hazard quotient is reported for different age groups. Paraiso City in Tabasco State reported the highest values for over 19 years old group (0.49). It was concluded that there was no threat to human health due to H2S emissions derived from the maritime terminal for the studied sites.

Air Pollution in the Gulf of Mexico

An integral analysis of Air Pollution in the Gulf of Mexico was made considering pollutants emissions assessment and diagnosis;air pollution monitoring;and modeling of air pollution dispersion. Combustion sources considered in this work were: thermoelectric power plants and open flares;and pollutants considered were sulfur dioxide, nitrogen dioxides, particulate matter (PM10 and PM2.5), Total suspended particles (TSP) and carbon monoxide (CO). This study made evident a lack of more recent information and a homogenization in emissions factors in order to know the conditions of air pollution in the Gulf of Mexico in a more reliable way.

Keggin Structure and Surface Acidity of 12-Phosphotungstic Acid Grafted Zr-MCM-48 Mesoporous Molecular Sieves

A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Br?nsted acid sites and acidity strength in comparison with the bare support. At 100°C, the 30 wt% H3PW12O40/Zr-MCM-48 contained 174 μmol/g Br?nsted acid sites which were 14.5 times greater than that of Zr-MCM-48. The Keggin structure of the grafted heteropolyacid was rather stable after calcination at 400°C for 2 h, approximately 93.3% of Keggin structure in the dispersed heteropolyacid were remained without destruction but slightly distorted in some degree, as evidenced by FTIR characterization and 31P NMR-MAS analysis. This H3PW12O40/Zr-MCM-48 solid with three dimensional mesoporous system, large surface area and very strong Br?nsted acidity will be a promising catalyst for acid catalytic reactions.

Steel Pitting Corrosion Analysis, Using a High Vaccum Epoxy Penetration Technique

An epoxy penetration technique was used to reproduce and analyze the pitting corrosion process occurred at a steel coupon surface. The samples were exposed to the resin under high vacuum conditions, in order to fulfill the pits caused by the corrosion process. With this technique, a 3D image of the corrosion damages was obtained. Once the image of the damaged surface was obtained, a Scanning Electron Microscope (SEM) was used to analyze the morphology of the pits exhibited by the steel sample. The results were satisfactory, as different parameters such as the diameter, shape and depth of the pits originated, along with the corrosion preferential path, could be established. According to the results, the use of the epoxy penetration technique may be considered as alternating pitting corrosion analysis technique.

Synthesis and Structural Characterization of Monocrystalline α-V2O5 Nanowires

A stable one-dimensional system in an orthorhombic α-V2O5 nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic V2O5 structure. The starting material was firstly submitted to acid hydrolysis in H2O2 followed by a solvothermal treatment. The outcome of this procedure, a metastable phase of the one-dimensional system V10O24·12H2O/V3O7·H2O, was subsequently reoxidized by controlled heating in an open air system. The final product was an orange crystalline solid mainly formed by monocrystalline nanowires of α-V2O5 having lengths of tens of micrometers and widths of about 75 nm with a preferential [200] growth direction. It was found that the pH value of the initial solution plays an important role in the formation of the crystalline phase in the final products. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). This study offers an alternate route for the synthesis of vanadium oxides and related compounds.