Molecular composition of low-temperature oxidation products of the heavy oil

Low-temperature oxidation(LTO)is the main reaction that affects fuel formation in the in-situ combustion process,which has important significance for the subsequent combustion propulsion and the successful extraction of crude oil.In this study,heavy oil was subjected to LTO reactions at different temperatures.Three types of reaction products with varying oxidation depths were characterized in terms of the number of oxygen atoms and the polarity of the molecule to reveal the low-temperature oxidation process of the heavy oil.Ketone compounds and acid polyoxides in the oil phase and deep oxidation products with a higher number of oxygen atoms in the coke were identified with increasing oxidation depth.The experimental results showed that the oxidation reaction of the heavy oil changed from kinetic-controlled to diffusion-controlled in the open oxidation system of the heavy oil as the oxidation depth increased.The oxidation reaction of the oil phase reached a maximum and stable value in oxygen content.The molecular compositions of the ketone compound and acid polyoxide did not change significantly with further increase in reaction temperature.The molecular compositions of the deep oxidation products with a higher number of oxygen atoms in the coke phase changed significantly.The coke precursor molecules with a lower oxygen content and condensation degree participated in the coke formation,and the oxidation reaction pathway and the complexity of the oxidation product component also increased.

The Influence of Paraffinic Base Oil on Low-temperature Viscosity of Naphthenic Base Oil

Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthenic base oil was investigated by studying the low-temperature viscosity of tested oils. The viscosity of lube oils increased with an increasing content of high-viscosity paraffinic base oil in the oil mixture. And the low-temperature viscosity was less influenced when the content of paraffinic base oil in the mixture was insignificant. In order to reduce the cost for formulating lubricating oil, a small fraction of paraffinic base oil can be added into naphthenic base oil as far as the property of lubricating oil can meet the specification. According to the study on low-temperature viscosity of the oil mixed with paraffinic base oil and naphthenic base oil, a basic rule was worked out for the preparation of qualified lubricating oils.

In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

The low-temperature catalytic oxidation of heavy crude oil（Xinjiang Oilfield,China） was studied using three types of catalysts including oil-soluble,watersoluble,and dispersed catalysts.According to primary screening,oil-soluble catalysts,copper naphthenate and manganese naphthenate,are more attractive,and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil.The heavy oil compositions and molecular structures were characterized by column chromatography,elemental analysis,and Fourier transform infrared spectrometry before and after reaction.An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity-temperature characteristics.Results show that the two oil-soluble catalysts can crack part of heavy components into light components,decrease the heteroatom content,and achieve the transition of reaction mode from oxygen addition to bond scission.The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil（oil viscosity and contents of heavy fractions）.It is found that the temperature,oil composition,and internal molecular structures are the main factors affecting its flow ability.Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.

Low-temperature oxidation of light crude oil in oxygen-reduced air flooding

Light crude oil from the lower member of the Paleogene Xiaganchaigou Formation of Gaskule in Qinghai Oilfield was selected to carry out thermal kinetic analysis experiments and calculate the activation energy during the oil oxidation process.The oxidation process of crude oi l in porous medium was modeled by crude oil static oxidation experiment,and the component changes of crude oil before and after low-temperature oxidation were compared through Fourier transform ion cy-clotron resonance mass spectrometry and gas chromatography;the dynamic displacement experiment of oxygen-reduced air was combined with NMR technology to analyze the oil recovery degree of oxygen-reduced air flooding.The whole process of crude oil oxidation can be divided into four stages:light hydrocarbon volatilization,low-temperature oxidation,fuel deposition,and high temperature oxidation;the high temperature oxidation stage needs the highest activation energy,followed by the fuel deposition stage,and the low-temperature oxidation stage needs the lowest activation energy;the concentration of oxygen in the reaction is negatively correlated with the activation energy required for the reaction;the higher the oxygen concentration,the lower the average activation energy required for oxidation reaction is;the low-temperature oxidation reaction between crude oil and air generates a large amount of heat and CO,CO_(2) and CH4,forming flue gas drive in the reservoir,which has certain effects of mixing phases,reducing viscosity,lowering interfacial tension and promoting expansion of crude oil,and thus helps enhance the oil recovery rate.Under suitable reservoir temperature condition,the degree of recovery of oxygen-reduced air flooding is higher than that of nitrogen flooding for all scales of pore throat,and the air/oxygen-reduced air flooding de-velopment should be preferred.

The occurrence characteristics of oil in shales matrix from organic geochemical screening data and pore structure properties:An experimental study Author links open overlay panel

The occurrence characteristics of shale oil are of great significance to the movability of shale oil.In this study,the occurrence characteristics of oil in the shale matrix at Funing Formation shale in Subei Basin were quantitatively evaluated by organic geochemistry and microscopic pore structure characterization experiments.The Multiple Isothermal Stages Pyrolysis(MIS)experiment results show that the content of total oil,adsorbed oil,and free oil in the shales are 3.15-11.25 mg/g,1.41-4.95 mg/g,and 1.74-6.51 mg/g,respectively.among which the silicon-rich shale has the best oil-bearing.The relative content of free oil shows an increasing trend in pores with pore diameters greater than 3 nm.When the relative content of free oil reaches 100%,the pore size of silicon-rich shale is about 200 nm,while that of calcium-rich shale,clay-rich shale,and siliceous mixed shale is about 10 nm.The occurrence law of adsorbed oil is opposite to that of free oil,which indicates that shale oil will occur in the pores and fractures in a free state in a more extensive pore size range(>200 nm).This study also enables us to further understand the occurrence characteristics of shale oil under the interaction of occurrence state and occurrence space.

A Markov-switching dynamic regression analysis of the asymmetries related to the determinants of US crude oil production between 1982 and 2019

The structural changes brought about by shale oil revolution have inspired this paper of which the aim is to analyze the potential asymmetries related to the determinants of crude oil production in the USA.Thus,using a Markov-switching dynamic regression model in which parameters change when oil production moves from one regime to the other,it is found that for both oil production and oil relative importance,the regime that was dominant during the 1980s and the early 1990s when oil production in the USA was substantially high is the same regime that has once again become dominant in the decade corresponding to the shale oil revolution.Furthermore,the study reveals the existence of asymmetries in the relationship between US crude oil production and both manufacturing production and the consumer price index.Asymmetries are also found in the relationship between the relative importance US crude oil and manufacturing production.Finally,it is found that the intercept and the variance parameter also vary from one regime to the other,thus justifying the use of regime-dependent models.

Determination of petroleum sulfonates in crude oil by column-switching anion-exchange chromatography

A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates （PMS） and petroleum disulfonates （PDS） in crude oil that was simply diluted with the dichloromethane/methanol （60/40）. The high performance liquid chromatography （HPLC） system consisted of a clean-up column and an analytical column, which were connected with two six-port switching valves. Detection of petroleum sulfonates was available and repeatable. This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.

Method of Predicting Water Content in Crude Oil Based on Measuring Range Automatic Switching

Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error of water content in crude oil proposed in this paper is based on switching measuring ranges of on-line water content analyzer automatically.Measuring precision on data collected from oil field and analyzed by in-field operators can be impressively improved by using back propogation （BP） neural network to predict water content in output crude oil.Application results show that the difficulty in accurately measuring water-oil content ratio can be solved effectively through this combination of on-line measuring range automatic switching and real time prediction,as this method has been tested repeatedly on-site in oil fields with satisfactory prediction results.

Markov-Switching Time-Varying Copula Modeling of Dependence Structure between Oil and GCC Stock Markets

This paper proposes a Markov-switching copula model to examine the presence of regime change in the time-varying dependence structure between oil price changes and stock market returns in six GCC countries. The marginal distributions are assumed to follow a long-memory model while the copula parameters are supposed to evolve according to the Markov-switching process. Furthermore, we estimate the Value-at-Risk (VaR) based on the proposed approach. The empirical results provide evidence of three regime changes, representing precrisis, financial crisis and post-crisis, in the dependence structure between energy and GCC stock markets. In particular, in the pre- and post-crisis regimes, there is no dependence, while in the crisis regime, there is significant tail dependence. For OPEC countries, we find lower tail dependence whereas in non-OPEC countries, we see upper tail dependence. VaR experiments show that the Markov-switching time- varying copula model performs better than the time-varying copula model.

Study on the Catalytic Reforming Law of Solid-Phase Carbon and Nitrogen Sources Loaded with MnO_(2)at Low Temperatures in Tahe Heavy Oil

MnO_(2)/Melem composites were synthesized with MnO_(2)nanoparticles loaded onto the Melem using the hydrothermal method.As raw materials for C and N carriers,Melem was prepared from melamine roasted at 354℃,and KMnO_(4)as a raw material for Mn,MnO_(2)nanoparticles were prepared using the hydrothermal synthesis of KMnO_(4).Scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and a laser particle size analyzer were used for structural characterization,and the catalytic oxidation performance of the heavy oil was investigated at different reaction temperatures(100℃to 180℃)using MnO_(2)/Melem with an oxidant and donor protonic acid.The results showed that the synthesizedβ-MnO_(2)nanoparticles were successfully loaded onto the Melem surface;the oil samples before and after the reaction at different temperatures were subjected to SARA analysis using Fourier transform infrared(FT-IR),elemental analysis,gas chromatography-mass spectrometry(GC-MS)and viscosity tests,respectively.It was determined that the hydrocarbons in the crude oil were converted to heavy mass by oxidation reactions with the oxidant mainly through a low-temperature oxidation process below 140℃in the heavy oil when the temperature exceeds 140℃,in addition to the oxidation reaction with the oxidant,a cleavage reaction in the carbon chain occurs to form hydrocarbon substances with lower molecular weights.

基于SPS的输油泵无扰切换控制与优化

长输管道运行中经常进行备用输油泵切换,直接切换备用泵会引起管道压力大范围波动,甚至触发水击超前保护程序,导致管道停输事故。为降低输油泵切换过程压力波动,结合工程实际泵切换过程,基于SPS水力软件对工频泵切换工频泵、工频泵切换变频泵、变频泵切换工频泵3种工况进行模拟,优化输油泵切换过程,提出输油泵无扰切换策略。通过SPS软件模拟结果与实测结果吻合度较高,相对误差基本在10%以内;优化后输油泵切换引起的压力波动在±0.2 MPa范围内,压力波动小,可以实现无扰切换。输油泵无扰切换对长输管道运行控制具有一定的指导意义。

变压器真空有载分接开关绝缘油的检测与分析

变压器有载调压分接开关(以下简称分接开关)是变压器在不停电的情况下完成输出电压调节的核心组件。近年来,真空有载调压分接开关在电网企业中开始运用。真空有载分接开关的绝缘油检测是确保其安全稳定运行的重要手段。本文通过对某局110 kV以上的45台主变中真空有载调压分接开关的绝缘油检测与分析的实践,提出与之相关的运维建议。

基于深度残差网络的输油气站场双电源快速切换风险预警模型

为准确预警输油气站场双电源快速切换风险,保证输油气站场双电源快速切换装置安全,构建基于深度残差网络的输油气站场双电源快速切换风险预警模型。在分析输油气站场双电源快速切换原理、输油气站场双电源快速切换风险的影响因素之后,构建输油气站场双电源快速切换风险的预警指标。通过基于优化D-S理论的多源预警指标融合方法,将所构建的多种双电源快速切换风险预警指标融合,建立风险预警样本,作为基于深度残差网络的双电源快速切换装置风险识别模型的识别样本,识别输油气站场双电源快速切换装置是否存在风险,并根据识别结果进行准确预警。经测试,所构建模型对输油气站场双电源快速切换风险的预警精度大于0.95,精度较高。

ZGM95-3中速辊式磨煤机油站控制系统存在的问题及整改措施

针对建投邢台热电有限责任公司的2×350MW机组磨煤机油站控制系统熔断器在运行可靠性上无法满足要求的问题,存在着影响机组负荷的事故隐患,判断磨辊控制回路中的继电器和液压换向阀控制回路中的继电器通电后电流过大是导致1号熔断器短路的主要原因,提出了磨煤机油站控制系统加装单级开关的改造方案,以保证机组安全可靠稳定运行,提高机组的经济效益。

大型燃气电厂变压器冷却器前馈模糊控制研究

针对大型燃气电厂变压器负荷变化大的特点,提出了以启停冷却器组为执行手段的前馈模糊控制策略,以满足变压器温控要求。在油浸强迫油循环风冷式(OFAF)冷却器机理研究基础上归纳了模糊控制规则,以实现对变压器油温的闭环调节,并通过前馈控制补偿变压器功率扰动给油温带来的影响。在Simulink平台构建了OFAF冷却器仿真控制模型,验证了变压器OFAF冷却器前馈模糊控制策略的可行性和有效性;并通过对比两种控制执行方式下的结果,分析了以启停冷却器组为执行手段的优势。

8800HP级OSV应急用电逻辑优化

基于对8800HP系列海洋工程拖轮主机滑油备用泵应急用电逻辑优化,阐述优化动机及优化方案制定,并介绍主机及主机滑油备用泵操作方法及特殊情况下的应急恢复动力方法及原理。

500 kVA变压器油浸风冷系统控制分析

500 kV变压器作为电力系统中的主要设备,其冷却系统是保障变压器安全、稳定运行的重要辅助装置。当风冷系统无法正常工作时,如不及时排除故障将会对变压器正常运行造成严重的安全隐患,甚至造成变压器异常退出运行。文章对油浸变压器风冷控制策略进行了详细介绍,并给出了分析模板;同时,基于500 kVA变压器油浸风冷系统实况,阐述了油浸变压器典型风冷控制中的“风机组智能切换”策略。

A New Method for Predicting Wall Sticking Occurrence Temperature of High Water Cut Crude Oil

In crude oil transportation, adhesion of oil on pipe wall can cause partial or total blockage of the pipe. This process is significantly affected by wall sticking occurrence temperature(WSOT). In this work, an efficient approach for estimating WSOT of high water-cut oil, which can agree well with the actual environment of multiphase transportation pipeline, is proposed. Based on the energy dissipation theory, it is possible to make comparison of average shear rates between the stirred vessel and the flow loop. The impacts of water content and shear rate on WSOT are investigated using the stirred vessel and the flow loop. Good agreement has been observed between the stirred vessel and the flow loop results with the maximum and the average absolute deviations equating to 3.30 °C and 2.18 °C, respectively. The development of gathering scheme can enjoy some benefits from this method.

Extraordinary Compatibility to Mass Loading and Rate Capability of Hierarchically Porous Carbon Nanorods Electrode Derived from the Waste Tire Pyrolysis Oil

The conversion of waste tire pyrolysis oil(WTPO)into S-doped porous carbon nanorods(labeled as WPCNs)with hierarchical pore structure is realized by a simple template-directed approach.The specific surface area of as-obtained porous carbon nanorods can reach up to 1448 m^(2) g^(−1) without the addition of any activating agent.As the capacitive electrode,WPCNs possess the extraordinary compatibility to capacitance,different electrolyte systems as well as long-term cycle life even at a commercial-level areal mass loading(10 mg cm^(−2)).Besides,only an extremely small capacitance fluctuation is observed under the extreme circumstance(−40 to 80℃),reflecting the excellent high-and low-temperature performance.The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores-dominated asphalt-derived porous carbon nanorods(APCNs)and micropores-dominated activated carbon.The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as-prepared carbon materials under different pore size distribution.The total ion flow(NT)of WPCNs calculated by the simulation is obviously larger than APCNs and the N_(T) ratio between them is similar with the experimental average capacitance ratio.Furthermore,this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value-added utilization of WTPO.

Impact of Switch to Fosamprenavir and Addition of Lovaza^®for Treatment of Hypertriglyceridemia in HIV-Infected Subjects on Antiretroviral Therapy

Background: Managing hypertriglyceridemia in HIV-infected patients often requires multiple pharmacologic strategies. Many protease inhibitors (PIs), one of 6 classes of drugs used to treat HIV, have been associated with hypercholesterolemia and drug interactions. For this study, we examined a dual strategy to manage hypertriglyceridemia in HIV-infected patient taking PIs: 1) switching patients to fosamprenavir (FPV), a PI with fewer drug interactions, and 2) adding prescription fish oil (LOVAZA?), which has been shown to reduce triglycerides. Methods: This multicenter, 24-week study enrolled 36 patients virologically suppressed (HIV-1 RNA <50 copies/mL) on PI-containing therapy with screening triglyceride levels of 200 - 1200 mg/dL and LDL cholesterol levels ≤160 mg/dL. At baseline, patients were switched to ritonavir (RTV)-boosted fosamprenavir (FPV 1400 mg/RTV 100 mg QD) and any lipid-lowering agents were stopped. At Week 6, LOVAZA 4 g QD was added. Results: Five patients prematurely discontinued due to adverse events (2), non-compliance, lost-to-follow up, and protocol violation. Median triglyceride concentration was 303 mg/dL at screening, 262 mg/dL at baseline, 290 mg/dL at Week 6 (+8% from baseline), and 218 mg/dL at Week 24 (–30% from Week 6). At Week 24, 39% (12/31) of patients had triglycerides <200 mg/dL. Among patients reaching Week 24, 100% (31/31) and 90% (28/31) had HIV-1 RNA <400 and <50 copies/mL, respectively. Conclusions: In this study, a switch to FPV/RTV followed by LOVAZA decreased median triglyceride levels and modestly increased the percentage of patients with triglyceride levels <200 mg/dL while maintaining virologic suppression in HIV-infected subjects with hypertriglyceridemia. Our data suggest that baseline PI may affect the likelihood of achieving triglycerides <200 mg/dL after 18 weeks on study. A larger study would be needed to understand the relative contributions of choice of protease inhibitor and LOVAZA to triglyceride concentrations in HIV-infected patients.