A comparative study of the carbon dioxide and nitrogen minimum miscibility pressure determinations for an Iranian light oil sample

Miscible gas injection is an approved profitable process that could significantly enhance oil recovery from different types of reservoirs while the major factor affecting its efficiency would be the minimum miscibility pressure (MMP) value. A recent experimental technique, known as vanishing interfacial tension (VIT), can estimate the MMP for gas–oil mixtures by measuring interfacial tension values and extrapolating them to zero at a sequence of pressures. Compositional simulation models are also useful in MMP determination by tuning an equation of state to compute the realistic phase behavior of reservoir fluid. In this paper, the capability and quality of MMP prediction via different methods such as laboratory slim tube tests, VIT technique, compositional simulation, and various empirical correlations were examined using a light oil sample taken from an Iranian carbonate reservoir, employing two pure gases of CO₂ and N₂ as the injectants. The accuracy and validation of the mentioned methods were then confirmed successfully by obtaining negligible overall absolute deviation percentages (AD%) compared with the conducted slim tube tests results.     

Wetting and Cooling Performance of Vegetable Oils during Quench Hardening

Wetting kinetics, kinematics, and cooling performance of vegetable oils (sunflower, gingelly, palm, and coconut oils) during quenching of Inconel 600 probe were studied using goniometry, online video imaging, and cooling curve analysis. The results were compared with a conventional mineral oil quench medium. Improved wettability was obtained for vegetable oils with lower viscosity. Cooling curve analyses showed three stages of cooling for both mineral and vegetable oils. Video imaging of the quenching process and differential scanning calorimetry analysis confirmed that the first stage of cooling was caused by the formation of vapor film in mineral oil and due to the occurrence of a heated liquid layer around the quench probe surface in vegetable oils. Vegetable oils showed continuous boiling phenomenon during the convective cooling stage of quenching. The cooling performance of vegetable oils was found to depend on the concentration of mono‐unsaturated fatty acid. The heat extracting capability of vegetable oils with lower mono‐unsaturated fatty acid oils was found to be higher. However, no correlation was observed between fatty acid composition and uniformity of heat transfer. When compared to mineral oil quenching, vegetable oil quenching produced faster wetting kinematics and better cooling performance.     

Fouling Management of Thermal Cracking Units

ABSTRACT

Visbreakers and other thermal cracking units are thermal process units in crude oil refineries that upgrade heavy petroleum, usually residual oils produced from atmospheric or vacuum distillation of crude oil. The associated process streams of these units consist of heavy hydrocarbons with very high viscosities and impurities, resulting in fouling of the heat exchangers used to cool or heat these streams. This paper presents a practical fouling analysis for thermal cracking units in a refinery in Germany. Fouling management at this refinery was initiated as part of the refinery energy-saving program. Following similar analysis of the refinery's crude preheat trains, heat exchanger networks associated in the thermal cracking units were modeled by entering the plant monitoring data, network topology, and heat exchanger geometries into a commercial heat exchanger network simulator, SmartPM. Fouling behaviors of vacuum residue streams and thermal cracker residue streams were identified and quantified. Both chemical reaction fouling and particulate fouling mechanisms were identified to be responsible for the fouling in these streams. Dynamic fouling models were fitted and used to predict fouling of these heavy petroleum streams, which fouled on both the shell and tube sides of the shell-and-tube heat exchangers.     

Biodiesel production from residual oils recovered from spent bleaching earth

This work was to study technical and economic feasibilities of converting residual oils recovered from spent bleaching earth generated at soybean oil refineries into useable biodiesel. Experimental results showed that fatty acids in the SBE residual oil were hexadecenoic acid (58.19%), stearic acid (21.49%) and oleic acid (20.32%), which were similar to those of vegetable oils. The methyl ester conversion via a transesterification process gave a yield between 85 and 90%. The biodiesel qualities were in reasonable agreement with both EN 14214 and ASTM D6751 standards. A preliminary financial analysis showed that the production cost of biodiesel from SBE oils was significantly lower than the pre-tax price of fossil diesel or those made of vegetable oils or waste cooking oils. The effects of the crude oil price and the investment on the production cost and the investment return period were also conducted. The result showed that the investment would return faster at higher crude oil price.     

Structural analysis of bio-oils from sub-and supercritical water liquefaction of woody biomass

Woody biomass was liquefied by water in an autoclave in the reaction temperature range of 280–420 °C with sodium carbonate as the catalyst. The experimental results show that the yield of the main liquefaction product (heavy oil) was significantly influenced by the process conditions. The maximum yield of heavy oil was obtained at reaction temperature 380 °C. The heavy oils obtained at different reaction temperature were analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS). The analytical results show the heavy oil is complex compound that contain hydrocarbon, aldehyde, ketone, hydroxybenzene and ester.     

Deposition from Crude Oils in Heat Exchangers

Deposition in flow lines and processing and heat transfer equipment arises from fouling species, which may either be present in the fluid or generated in the vicinity of the equipment surface. Recent research on deposition during heat transfer from petroleum feedstocks is reviewed. For low-sulfur light crude oils, deposition is largely due to particulates and gums. For medium-sulfur crude oils, the formation of iron sulfides plays a major role in deposition. In unstable heavy oil systems, suspended asphaltenes are the fouling species. Trace quantities of impurities such as dissolved oxygen or suspended corrosion products add markedly to deposit formation. The influences of flow velocity, bulk and surface temperatures, and particulate concentrations are demonstrated through experimental results and compared to expectations from simple models. Through an understanding of the key steps in the deposition processes, a rational mitigation strategy can be formulated.     

Utilization of produced gas of CO2 flooding to improve oil recovery

Large amounts of mixed gas containing CO₂ and hydrocarbon would be produced during CO₂ flooding. Injecting the produced gas back to reservoir can not only make full use of CO₂, but also can reduce air contamination. Taking produced crude oil and gases with different CO₂ concentration from Jilin oilfield as examples in this paper, the phase behavior and the physical properties of live oil-gas system were measured with a visible PVT apparatus. In terms of oil viscosity reduction and swelling, the gas with high CO₂ concentration was found to be substantially effective. Furthermore, comparative slim tube tests of the oil recovery performance using the five kinds of gases under different operating pressure were conducted in one-dimensional model. Results indicate that displacement efficiency increases linearly with the increasing CO₂ content in the recycle gas; displacement efficiency increases with operating pressure under immiscible conditions. Re-injecting produced gas with relative high CO₂ concentration back to reservoir is a method both time-saving and cost-effective.     

Placing Brazil's heavy acid oils on international markets

This paper identifies the international market niches of Brazil's heavy acid oils. It analyzes the perspectives for making wider use of heavy acid oils, assessing their importance for certain oil-producing regions such as Brazil, Venezuela, West Africa, the North Sea and China. Within this context, the oil produced in the Marlim Field offshore Brazil is of specific interest, spurred by the development of its commercial brand name for placement on international markets and backed by ample production volumes. This analysis indicates keener international competition among acid oils produced in Brazil, the North Sea and the West Coast of Africa, through to 2010. However, over the long term, refinery conversion capacity is the key factor for channeling larger volumes of heavy acid oils to the international market. In this case, the future of acid oil producers will depend on investments in refineries close to oil product consumption centers. For Brazil, this means investments in modifying its refineries and setting up partnerships in the downstream segment for consumer centers absorbing all products of high added value, such as the USA and even Southeast Asia and Western Europe.     

Vegetable oils as renewable fuels for power plants based on low and medium speed diesel engines

There is a high potential for plant oils as alternative fuel for low and medium speed diesel engines, making petroleum-derived fuels likely to be replaced in these types of engines. Vegetable oils have important advantages over both heavy fuel oil (HFO) and marine gas oil (MGO), the fuels currently used in diesel power plants by large two stroke low-speed diesel engines and by medium speed diesel engines, respectively. The emission of certain pollutants and greenhouse gases like SO_x, soot and, mainly, CO₂ can be reduced by using vegetable oils in these types of engines. This work discusses the potential of vegetable oils as fuel for power plant diesel engines and the problems that can be derived from their use. Current experiences with medium speed diesel engines together with the analysis carried out in this paper indicate that vegetable oils can substitute HFO and MGO, without almost any engine modification.     

Worldwide cheap and heavy oil productions: A long-term energy model

Crude oil, natural gas liquids, heavy oils, deepwater oils, and polar oils are non-renewable energy resources with increasing extraction costs. Two major definitions emerge: regular or ‘cheap’ oil and non-conventional or ‘heavy’ oil. Peaking time in conventional oil production has been a recent focus of debate. For two decades, non-conventional oils have been mixed with regular crude oil. Peaking time estimation and the rate at which production may be expected to decline, following the peak, are more difficult to determine. We propose a two-wave model for world oil production pattern and forecasting, based on the diffusion of innovation theories: a sequential multi-Bass model. Historical well-known shocks are confirmed, and new peaking times for crude oil and mixed oil are determined with corresponding depletion rates. In the final section, possible ties between the dynamics of oil extraction and refining capacities are discussed as a predictive symptom of an imminent mixed oil peak in 2016.     

Heavy oil catalytic upgrading with microwave heating over a microwave absorbing catalyst USY/AC/Al2O3

Microwave heating has attracted attention in heavy oil recovery and processing industry due to the benefits of volumetric, rapid and selective heating. The objective of this study is to prepare a microwave absorbing catalyst and examine its performance in catalytic upgrading of a heavy oil with microwave heating. It was found that oil viscosity decreased 90.00% and API gravity increased 1.24° after upgrading over a prepared catalyst. SARA analysis of upgraded oils showed that the contents of resins and asphaltenes decreased; meanwhile, saturates and aromatics contents increased. The participation of the catalyst in oil upgrading reactions was further confirmed by analyzing the hydrocarbons in gas product.     

油耗测量系统控制部分的设计

目前,安装电喷发动机油耗测量仪的传感器时都要拆动燃油管路,费时也浪费燃油,十分不便。论文设计了一种不用油耗传感器的电喷发动机油耗测量仪器,该仪器充分利用了电喷发动机电脑控制的精确供油信息,将各缸的供油信息进行采集、标定、运算后输出测量时间内的累计油耗和小时耗油量。安装时无需拆动燃油管路,无燃油损失,且测量方便、快捷。本文主要就油耗测量系统的控制部分作了介绍。     

油耗测量系统控制部分的设计

目前，安装电喷发动机油耗测量仪的传感器时都要拆动燃油管路，费时也浪费燃油，十分不便。论文设计了一种不用油耗传感器的电喷发动机油耗测量仪器，该仪器充分利用了电喷发动机电脑控制的精确供油信息，将各缸的供油信息进行采集、标定、运算后输出测量时间内的累计油耗和小时耗泸量。安装时无需拆动燃油管路，无燃油损失，且测量方便、快捷。本文主要就油耗测量系统的控制部分作了介绍。     

Forecasting the differences between various commercial oil prices in the Persian Gulf region by neural network

In this paper we have investigated the differences between the prices of different commercial oils of the Persian Gulf region. The prices of 7 different crude oils from Iran, Kuwait, Saudi Arabia, Oman, Abu Dhabi and Dubai were compared with the benchmark light oil of Saudi Arabia over the period January 2000-April 2010. A neural network is introduced to forecast the price of any commercial oil in these crude oils, provided that the price of the benchmark light oil of Saudi Arabia is already known or is predicted by another forecasting method. The designed neural network is able to predict the differences in the oil prices with an average error of 8.82% for testing and 7.24% for training data. It is claimed that the present method can promote the forecasting power of existing models to predict the price of any commercial oil instead of an average or benchmark value.     

燃气轮机重油处理系统方案研究

随着世界经济的发展，对石油资源的消耗也越来越多，为更充分利用有限的石油资源，重油逐渐被应用于电力生产，而发电用燃气轮机以重油作为燃料，可有效地降低运行成本，因此，重油的处理问题颇受重视。本文简要说明了燃气轮机燃用重油技术的一些特点，及燃用前重油的一些处理方法，特别针对重油的超临界水处理方法，设计了一个完整的处理系统，以除去重油中的钒元素，并对两种不同的超临界水—重油混合器结构进行了混合过程的数值分析，选取了一种较好的结构用于该处理系统，为更进一步将超临界水处理技术应用于燃气轮机燃用重油的系统中奠定了基础。     

Use of tobacco seed oil methyl ester in a turbocharged indirect injection diesel engine

Vegetable oils and their methyl/ethyl esters are alternative renewable fuels for compression ignition engines. Different kinds of vegetable oils and their methyl/ethyl esters have been tested in diesel engines. However, tobacco seed oil and tobacco seed oil methyl ester have not been tested in diesel engines, yet. Tobacco seed oil is a non-edible vegetable oil and a by-product of tobacco leaves production. To the author's best knowledge, this is the first study on tobacco seed oil methyl ester as a fuel in diesel engines.In this study, potential tobacco seed production throughout the world, the oil extraction process from tobacco seed and the transesterification process for biodiesel production were examined. The produced tobacco seed oil methyl ester was characterized by exposing its major properties. The effects of tobacco seed oil methyl ester addition to diesel No. 2 on the performance and emissions of a four cycle, four cylinder turbocharged indirect injection (IDI) diesel engine were examined at both full and partial loads. Experimental results showed that tobacco seed oil methyl ester can be partially substituted for the diesel fuel at most operating conditions in terms of performance parameters and emissions without any engine modification and preheating of the blends.     

Performance evaluation of a vegetable oil fuelled compression ignition engine

Fuel crisis because of dramatic increase in vehicular population and environmental concerns have renewed interest of scientific community to look for alternative fuels of bio-origin such as vegetable oils. Vegetable oils can be produced from forests, vegetable oil crops, and oil bearing biomass materials. Non-edible vegetable oils such as linseed oil, mahua oil, rice bran oil, etc. are potentially effective diesel substitute. Vegetable oils have high-energy content. This study was carried out to investigate the performance and emission characteristics of linseed oil, mahua oil, rice bran oil and linseed oil methyl ester (LOME), in a stationary single cylinder, four-stroke diesel engine and compare it with mineral diesel. The linseed oil, mahua oil, rice bran oil and LOME were blended with diesel in different proportions. Baseline data for diesel fuel was collected. Engine tests were performed using all these blends of linseed, mahua, rice bran, and LOME. Straight vegetable oils posed operational and durability problems when subjected to long-term usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. However, these problems were not observed for LOME blends. Hence, process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. Economic analysis was also done in this study and it is found that use of vegetable oil and its derivative as diesel fuel substitutes has almost similar cost as that of mineral diesel.     

Effect of Fe2O3 and WO3 nanoparticle on steam injection recovery

Nanotechnology has the potential to introduce revolutionary changes in several areas of oil and gas industry. In this paper, the effect of different concentrations of Fe₂O₃ and WO₃ nanoparticles at various temperatures was studied on viscosity of heavy oils. The effect of Fe₂O₃ and WO₃ nanoparticles mixture on steam injection process is studied. The experimental tests show that some of these nanoparticles decrease the heavy oil viscosity to less than 40% in certain concentration at different temperatures. Our results of steam injection tests show that the injection of Fe₂O₃ and WO₃ nanoparticles mixture increases the heavy oil recovery.     

重油燃烧技术的现状与展望

讨论重油燃烧存在的问题和目前的技术状态。重点介绍了液体燃料的预蒸发燃烧技术和利用预蒸发技术燃烧重油的可能性。应用预蒸发技术燃烧液体燃料具有高效率、低噪音排放、低有害气体特别是低NOx 排放和易调节等特点。     

An evaluation of enhanced oil recovery strategies for a heavy oil reservoir after cold production with sand

Cold heavy oil production with sand (CHOPS) is the process of choice for unconsolidated heavy oil reservoirs with relatively high gas content. The key challenge of CHOPS is that the recovery factor tends to be between 5% and 15%, implying that the majority of the oil remains in the ground after the process is rendered uneconomic. Continued cold production (without sands) is not productive for a post‐CHOPS reservoir because of the low oil saturation and depleted reservoir pressure in the wormhole regions. There is a need to develop viable recovery processes for post‐CHOPS reservoirs. Here, different follow‐up processes are examined for a post‐CHOPS heavy oil reservoir. In post‐CHOPS cold water flooding, severe water channeling is ineffective at displacing high viscosity heavy oil. Hot water flooding improves the sweep efficiency and produces more oil compared with cold water flooding. However, the swept region is limited to the domain between the neighboring wormhole networks, and the energy efficiency of the process is relatively poor. Compared with the hot water flooding case, steam flooding achieves higher oil production rates and lower water use. A cyclic steam stimulation strategy achieves the best performance regarding oil production rates and water usage. Based on our results, it is observed that thermally based techniques alone are not capable to recover the oil economically for post‐CHOPS reservoirs. However, it is suggested that techniques with combined use of thermal energy and solvent could potentially yield efficient oil recovery methods for these reservoirs. Copyright © 2015 John Wiley & Sons, Ltd.