Demulsification of petroleum emulsions using microwave separation method

The formation of emulsions during oil production and processing is a costly problem, both in terms of chemicals used and production losses. For economic and operational reasons, it is necessary to separate the water completely from crude oils before transporting or refining them. Experimental data are presented to show the influences of Triton X-100, low-sulfur wax residue (LSWR), sorbitan monooleate (Span 83) and sodium dodecyl sulfate (SDS) on the stability and microwave demulsification of petroleum emulsions. It was found that emulsion stability was related to several parameters including the surfactant concentration, water-to-oil phase ratio (10 to 90%), temperature and agitation speed. Based on this study, a possible emulsion-minimization approach utilizing microwave irradiation is suggested, which could be implemented in refineries. Compared with conventional heating, the use of microwave heating can significantly enhance the demulsification rate, reaching over 90 v/v% for the emulsions studied in this work

The Potential of Ultrasonic Membrane Anaerobic Systems in Treating Slaughterhouse Wastewater

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids. Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached to 94.8%

Surfactant–solid complex for enhancing the low in pipelines : An experimental approach

Background: Viscoelastic soluble polymeric additives have been used successfully for a long time as drag reducers in pipelines carrying commercial liquids like crude oil. Most of these polymers suffer from irreversible degradation when exposed to high shearing zones as in valves, elbows, and pumps which reduces, or eliminates, its flow enhancement effect. Insoluble additives were proven to be an effective drag reducer that overcomes the degradation drawback of soluble additives. On the other hand, insoluble additives suffer from the lack of viscoelasticity which limits their use as flow enhancers. The creation of complexes from soluble and insoluble additives is a field of research that is rarely explored despite its importance in introducing new flow enhancement methods for a higher drag reduction performance. The present work introduces a new surfactant–solid complex as a drag-reducing agent for turbulent flow in pipelines. Results: The surfactant, solid, and their complexes’ drag reduction performance was tested in a closed-loop turbulent flow liquid circulation system, while rheological characteristics of the soluble additives were tested using a standard rheometer. All the surfactant solutions showed non-Newtonian shear thinning behavior in all the investigated concentrations that ranged between 500 and 1300 wppm. The initial experimental result indicated that the surfactant solution's drag reduction performance was higher than that of the solid suspensions. On the other hand, the drag reduction performance was enhanced by 52% when creating a 1300 wppm surfactant–2000 wppm solid complex. This improvement in the drag reduction performance is due to the formation of surfactant–solid-enforced aggregates with high resistance to shear forces and high turbulence suppression efficiency. Conclusions: The present work introduces a new drag reduction solid–surfactant complex by creating aggregates combining the viscoelastic properties of surfactants with the resistance to high shear forces exerted by the solid particles. The polar nature of the surfactant micelles that form in single-phase flow systems contributed significantly to trapping the solid's micro-particles as enforcement to resist the shearing forces applied by the turbulent flow system

Prevalence of somatisation and psychologisation among patients visiting primary health care centres in the State of Qatar

Background: Medically unexplained somatic complaints are among the most common clinical presentations in primary care in developing countries and they are considerable burden for patients and health care system. Objectives: The aim of this study was to determine the prevalence of somatisation in comparison to psychologisation among a sample of Qatari patients who were visiting primary health care (PHC) centres and to investigate the clinical and socio-demographic characteristics of somatisers (STs) and psychologisers (PGs). Method: The survey was conducted among PHC Qatari patients during the period from January to July 2007. About 2,320 patients were approached, of whom 1,689 agreed to participate and responded to the questionnaire. Among the studied Qatari patients, 404 patients were identified for clinical interview. The first stage of the study was conducted with the help of general practitioners, using the 12-item General Health Questionnaire. The second stage was carried out by a consultant using the Clinical Interview Schedule. A specific operational criterion was used to identify STs and PGs. Results: The prevalence rate of STs among the total studied sample was 12.4%, while the PGs were 11.5%. Among the identified psychiatric cases, the proportion of STs (52%) was higher than PGs (48%). Most of the diagnostic categories were more prevalent among PGs. The dissatisfaction at work and stressful life events within 12 months before the onset of the presenting symptoms were the three postulated determinants which were significantly more among STs than PGs. Conclusion: The prevalence of somatised mental disorder was little higher than the psychologised mental disorder. The prevalence of somatisation and psychologisation is comparable with other reported studies from the Middle-East and Western countries. Dissatisfaction at work and stressful life events were significantly higher among STs than PGs

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Basic dye removal from synthetic wastewater by adsorption on palm ash

Palm ash, an agriculture waste residue from palm oil industry in Malaysia, was investigated as a replacement for the current expensive activated carbon adsorbent for removing of basic blue 66 dye from synthetic wastewater. Adsorption equilibrium and kinetics of basic dye from aqueous solutions onto palm oil were studied in a batch system. Effects of the initial concentration (50 to 600 mg/l), contact time, pH (2-12) and temperature on adsorption rate were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Redlich-Peterson models of adsorption. Equilibrium data fitted well Langmuir, Freundlich and Redlich-Peterson models in the range of 50-600 mg/l. The kinetic models pseudo firstorder and pseudo-second-order were tested to investigate the adsorption mechanisms. It was shown that second-order kinetic equation could best describe the adsorption kinetics. The results indicate that the activated palm ash could be employed as a low cost alternative to commercial activated carbon

Bio-polymers for Improving Liquid Flow in Pipelines - A Review and Future Work Opportunities

Several decades following Tom's discoveries on polymeric drag reducing agents (DRA) continue to see research efforts to produce robust and shear-stable DRA. Most efforts revolve around established artificial polymers, but questions have been raised recently about their environmental impact and safety. As such, a large number of researchers are looking into natural materials especially bio-polymers as substitutes. Several bio-polymers are found to exhibit drag reducing capabilities in aqueous media. All these factors suggest that bio-polymers would make a suitable alternative to artificial DRAs. This paper aims to present several works to-date on bio-polymer DRAs, and expose new possibilities

Demulsification of Triton X-100, Low-Sulfur Wax Residue (LSWR), Sorbitan monooleate (Span 83) and Sodium Dodecyl Sulfate (SDS)-Stabilized petroleum emulsions with a microwave separation method

The formation of emulsions during oil production and processing is a costly problem both in terms of chemicals used and production losses. For economic and operational reasons, it is necessary to separate the water completely from crude oils before transporting or refining them. Experimental data are presented to show the influences of Triton X-100, lowsulfur wax residue (LSWR), sorbitan monooleate (Span 83) and sodium dodecyl sulfate (SDS) on the stability and microwave demulsification of petroleum emulsions. It was found that emulsion stability was related to several parameters including the surfactant concentration, water-to-oil phase ratio (10–90%), temperature and agitation speed. Based on this study, a possible emulsion-minimization approach utilizing microwave irradiation is suggested, which could be implemented in refineries. Compared with conventional heating the use of microwave heating can significantly enhance the demulsification rate, reaching over 90 v/v% for the emulsions studied in this work

Investigating the effect of insoluble additives type on the drag reduction performance in a crude oil turbulent flow system

In the present work, the effect of three insoluble additives densities on reducing the drag of crude oil was investigated. The objective of the present work is to evaluate the effect of the insoluble additive’s densities on their drag reduction efficiency in hydrocarbon flow medium. Three powders with different densities are chosen, namely carbon powder, glass powder, and copper powder, with a density of 1710 kg/m3 , 2550 kg/m3 , and 8950 kg/m3 , respectively. The turbulence flow environment was created in a custom-made rotating disc apparatus with a maximum rotation speed of 300 rpm. To evaluate the effect of the powder density, the particle's size was chosen to be 100 µm. All the solutions were tested at the exact operating conditions with a rotation speed ranging between 200 to 2200 rpm. The experimental results showed a clear effect of the powder density on the drag reduction performance. The glass powders showed the highest drag reduction effect, while the copper and carbon powders were lower. The effect of the degree of turbulence on the drag reduction performance of the powders was clear, where the interaction between the powders and the turbulence structures (eddies) governed the turbulence-suppression efficiency of the additives

Interaction between diabetes mellitus and hypertension on risk of hearing loss in highly endogamous population

Aim: The aim of this study was to determine the prevalence of hearing loss and its association with type 2 diabetes mellitus (T2DM) in a highly endogamous population