Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.

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.

Predictive methods for density and refractive index of naphthenic lubricating oils during solvent extraction process

Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products.Among the different properties of lubricating oils,density and refractive index are some of the most important properties which can both be used for petroleum fluid characterization.Predictions of density and refractive index for naphthenic oils during solvent extraction by DMSO obtained by the pseudo-component approach and the quadratic correlation were both examined.The pseudo-component approach is a method to predict density and refractive index from composition while the latter merely relates density to refractive index.Results indicated that the predictions yielded by the pseudo-component method were in good agreement with experimental data for naphthenic oils.And the use of a function of refractive index(FRI_(20))as a pseudo-component property remarkably improved n_(20)predictions for the naphthenic mixtures.However,the density and refractive index predictions obtained by the quadratic correlation exhibited significantly higher de-viations for naphthenic oils than those for paraffinic oils.Thus a new modified correlation of the same functional form was proposed for naphthenic oils.The modification significantly improved predictions for naphthenic oils,which presented similar accuracy as the pseudo-component approach.And the previous correlation was still used for paraffinic oils.Additionally,effect of temperature on density and refractive index of naphthenic oils was examined.Results showed that the modified quadratic correlation was accurate for describing the relationship between density and refractive index of naphthenic oils at 20-90℃.The temperature dependence of density and refractive index for the raffinates and the extracts could be accurately described by the thermal coefficients for saturates and aromatics,respectively.Regarding the refractive index variation of the extracts with temperature,the empirical equation was proved to be a better option compared with the method using the thermal coefficient for aromatics.

Formulating Highway Paving Asphalts from the Vacuum Residue of a Paraffinic Crude

Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.

Prediction of Density and Refractive Index of Lubricating Oils during Secondary Solvent Extraction Process by Furfural

To meet the requirements for high aromatic content and low polycyclic aromatic(PCA)concentration,eco-friendly aromatic-rich rubber extender oils are usually produced by two-stage solvent extraction processes with furfural.Among the different properties of rubber processing oils,density and refractive index are some of the most important properties related to their final quality.Two types of methods,including a pseudo-component approach by using mixing rules and several correlations,were used for calculation of density and refractive index at 20℃ of paraffinic furfural-extract oils and their secondary raffinates.Results indicated that similar accuracy was obtained for predicting the density and the refractive index of furfural+furfural-extract paraffinic oil systems.However,the quadratic correlation presents its advantage over the pseudo-component approach when the composition of oils is not available.Moreover,the quadratic correlation was also used for naphthenic lubricating oils during two-stage solvent extraction processes.The predictions showed much larger discrepancies with respect to experimental values than those of paraffinic lubricating oils,which indicated that the quadratic correlation was more suitable for paraffinic oils with a CN value of below 37%.

Pediatric thermal burn injury:A retrospective analysis from pediatric care institutes,Eastern India

Objective:Pediatric burns pose difficult healthcare issues in underdeveloped nations.Due to the scarcity of pediatric burn care facilities and qualified burn‑care staff,patients are frequently referred from a rural hospital.This study explores the burn‑treatment approach that could be used in rural hospitals in the absence of a dedicated pediatric burn care facility.Materials and Methods:A retrospective analysis of clinical data of 199 children who received treatment for burn‑injury in an isolated general surgical ward.Wound debridement under anesthesia at the earliest was the cornerstone of the treatment plan for this cohort.Until the wounds healed,the treatment was repeated every alternate day.The patient’s demographic data,number of surgical dressings,length of hospital stay,and outcome were analyzed.Results:The mean age of the patients was 51.68±23.79 months.The male‑female ratio was 1.45:1.The survival rate was 99.00%.The disability rate was 4.52%.Univariate logistic regression identified the age group,total body surface area affected,depth of the wound,and time of intervention as statistically significant variables(P<0.05)predicting the disfigurement.Multivariate logistic regression identified the time intervals between surgical intervention and injury as an important predictor of morbidity.In addition,delayed presentation and delayed intervention led to a longer hospital stay,and more interventions than the early intervention cohort.Conclusions:Early debridement accelerates recovery and lessens the need for future skin grafts or contracture procedures.This approach can be used in rural hospitals as well because pediatric burns can be manageable in an isolated general ward.

Oleic Acid (OA), A Potential Dual Contrast Agent for Postmortem MR Angiography (PMMRA): A Pilot Study

Summary:Choosing proper perfusates as contrast agents is an important aspect for postmortem magnetic resonance angiography(PMMRA).However,in this emerging field,the number of suitable kinds of liquid is still very limited.The objective of this research is to compare MR images of oleic acid(OA)with paraffin oil(PO)in vitro and in ex situ animal hearts,in order to evaluate the feasibility to use OA as a novel contrast agent for PMMRA.In vitro,OA,PO and water(control)were introduced into three tubes separately and T,weighted-spin echo(Tw SE)and T2w-SE images were acquired on a 1.5T MR scanner.In the second experiment,0A and PO were injected into left coronary artery(LCA)and left ventricle(LV)of ex situ bovine hearts and their Tw-SE,Tzw-SE,Tw-multipoint Dixon(Tjw-mDixon)and 3DT2w-mDixon images were acquired.The overall results indicate that OA may have a potential to be used as a dual(T and T2 based)contrast agent for PMMRA when proper sequence parameters are utilized.However,as the pilot study was based on limited number of animal hearts,more researches using OA in cadavers are needed to validate our findings.

Base lubricants for green stamping:The effects of their structure and viscosity on tribological performance

The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed.In this investigation,the tribological performance of four base oils with different chemical structures(paraffinic and naphthenic)and viscosities(2 and 20 cSt),as well as water,was evaluated for the stamping of steel sheets and compared with a non-lubricated contact.Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts.Low-viscosity(LV)naphthenic oil performs very like both high-viscosity(HV)oils.A surprising exception is the LV paraffinic oil,with several-times-higher friction and wear compared to dry contact.This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low,leading to lubricant starvation.In contrast,HV oils provide a sufficiently thick lubricating film,while strong cohesive forces help in the film’s strength,lessening wear,and reducing friction.In thin-film lubrication with LV oils,such as when stamping,it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation,thus ensuring lower friction,less wear,and a longer lifetime of the contact.

Tribological evaluation of refined,bleached and deodorized palm stearin using four-ball tribotester with different normal loads

The effects of the mechanical factors with applied loads on the tribological performance of refined,bleached and deodorised(RBD) palm stearin(PS) were studied using a four-ball tribotester.All the RBD PS results were simultaneously compared with the additive-free paraffinic mineral oil(PMO).The experiments were carried out using different loads with a constant speed in order to gain a better understanding of the mechanical processes that occurred during the experiment.For each experiment,the temperature was increased to 75 °C and was run for 1 h.In a mechanical system,lubricant plays an important role in reducing wear and friction.PS exists as a semi-solid at room temperature after the fractionation process from oil palm.Due to the increasing rate of pollution to the environment,vegetable oil was chosen as the test lubricant with regard to its biodegradability.Other advantages of vegetable oil are that it is more easily harvestable and non-toxic compared to petroleum-based oil,which made it a suitable candidate.From the experiment,RBD PS is found to have a better friction constraint reduction compared with additive-free PMO.