A study on the characteristics of Algerian Hassi-Messaoud asphaltenes:Algerian Hassi-Messaoud asphaltenes: solubility and precipitation

This study focuses on detailed characterizations of asphaltene fractions extracted from the Algerian Hassi-Messaoud oil field. It was found that the extracted asphaltenes are not completely soluble in toluene, instead two fractions of asphaltenes were obtained upon solubilizing the heptane-precipitated neat asphaltenes in toluene. Extensive characterizations of the toluene-soluble and insoluble fractions were carried out using elemental analysis, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (ssNMR). It was suggested that the high oxygen content and uneven compositional structures are the main contributors to asphaltene instability. The toluene-insoluble fractions were found to have higher polarity and aromaticity as well as more oxygen content than the neat asphaltenes and toluene-soluble fractions

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Conversion of Petroleum Coke into Valuable Products using Catalytic and Non-Catalytic Oxy-Cracking Reaction

Every year millions of tons petroleum coke (petcoke) is generated as a by-product from bitumen and heavy oil upgrading due to the increasing demand in energy. Petcoke is a carbonaceous solid consisting of polycyclic aromatic hydrocarbons with low hydrogen content, derived from the processing of oil sands and oil refineries. The upgrading and treating of petcoke typically include thermal techniques such as gasification and combustion. However, several challenges limit the effectiveness of these conventional processes such as sulfur and CO2 emissions as well as high energy and costs associated with low efficiency. Therefore, finding an alternative, efficient, environmentally-friendly and cost-effective technology to treat these massive amounts of petcoke is needed. In this study, an oxy-cracking technique, which is a combination of oxidation and cracking reactions, is introduced as an alternative approach for petcoke utilization. This oxy-cracking takes place in basic aqueous media, at mild operation temperatures (170-230 oC) and pressures (500-600 psi). The oxy-cracking reaction mechanism was investigated using Quinolin-65 (Q-65) as a model molecule mimicking the residual feedstocks. Theoretical calaculations along with experimental reaction were carried out on Q-65 to explore the reaction pathways. Consequently, several operating conditions on petcoke oxy-cracking were investigated, such as temperature, oxygen pressure, reaction time, particle size and mixing rate to optimize the solubility and selectivity of oxy-cracked products. To enhance the oxy-cracking reaction conversion, an in-house prepared copper-silicate catalyst was introduced and characterized using BET, SEM, FTIR and XRD techniques. The oxy-cracking technique successfully converted the petcoke into valuable products, particularly humic acids analogs with other functional groups such as carboxylic, carbonyl, and sulfonic acids, as confirmed by FTIR, XPS and NMR analyses, in addition to minimal emission of CO2. Interestingly, based on the experimental findings, the metal contents in the obtained oxy-cracked products are significantly lower than that in the virgin petcoke. Consequently, the heating value and oxidation behaviour of the oxy-cracked products was investigated using TGA. These results showed that the oxy-cracked petcoke is easier and faster to oxidize compared to the virgin petcoke, suggesting that the oxy-cracked petcoke could be an alternative-clean fuel for power generation

Continuous adsorptive removal of glimepiride using multi-walled carbon nanotubes in fixed-bed column.

Water pollution by emerging pollutants such as pharmaceutical and personal care products is one of today's biggest challenges. The presence of these emerging contaminants in water has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and threat to health and safety. The antidiabetic drug glimepiride, GPD, is among these compounds, and it possesses adverse effects on human health if not carefully administered. Several conventional processes were proposed for the elimination of these persistent contaminants, and adsorption is among them. Therefore, in this study, the adsorptive removal of GPD from water using multi-walled carbon nanotubes (MWCNT) supported on silica was explored on a fixed-bed column. The effects of bed-height, solution pH, and flow rate on the adsorptive removal of GPD were investigated. The obtained adsorption parameters using Sips, Langmuir, and Freundlich models were used to investigate the continuous adsorption. The results showed that the drug removal is improved with the increasing bed height; however, it decreased with the flow rate. The effect of pH indicated that the adsorption is significantly affected and increased in acidic medium. The convection-dispersion model coupled with Freundlich isotherm was developed and used to describe the adsorption breakthrough curves. The maximum adsorption capacity (q) was 275.3 mg/g, and the axial dispersion coefficients were ranged between 3.5 and 9.0 × 10 m/s. The spent adsorbent was successfully regenerated at high pH by flushing with NaOH

Kinetic study of the thermo-oxidative decomposition of metformin by isoconversional and theoretical methods

The drug metformin is the most prescribed drug to treat type II diabetes and has been recently reported to have anticancer activities. Because of its wide use, its potential risk on the environment is extremely concerning. In this study, the mechanism and the thermodynamics of the thermo-oxidative decomposition of the metformin were investigated as part of a new solution for the pharmaceutical contamination of water bodies. Thermogravimetry and mass spectrometry were used to demonstrate the metformin thermo-oxidative decomposition under air in the temperature range 25–800 °C. The isoconversional methods of Kissinger-Akahira Sunose (KAS) and Friedman (FR) were implemented to deduce the trends of effective activation energies. As expected, the effective activation energy (Eα) of the reaction was dependent on the reaction temperature, suggesting multi-step reactions. The Eα ranged from 100 to 145 kJ/mol and 200–300 kJ/mol for the KAS and FR methods, respectively. The kinetic triplet, Aα, ΔS‡, and ΔG‡ were also determined by finding the appropriate reaction model. Theoretical calculations were implemented to propose a full reaction mechanism. The oxidation of metformin was investigated with both molecular O2(t) and atomic O(t) oxygen. The experimental results were then explained under the light of the computational data to explain the variation of Eα with temperature, and the competition between the O2(t)/O(t) species

Effect of PEG functionalized carbon nanotubes on the enhancement of thermal and physical properties of nanofluids

In this study, pristine carbon nanotubes and polyethylene glycol functionalized carbon nanotubes (CNT-PEG) have been used to enhance the heat capacity, viscosity, thermal conductivity, heat transfer rate and pressure drop of nanofluids. Multi-walled carbon nanotubes (MWCNT) were functionalized with polyethylene glycol (PEG) using a Fischer esterification method to improve their dispersion in aqueous media. Three concentrations of 0.01 wt%, 0.05 wt% and 0.1 wt% of pristine and functionalized CNTs in the nanofluids have been used. The heat-transfer rate and pressure drop of these nanofluids have been measured in a shell and tube heat exchanger. Differential Scanning Calorimetry (DSC) was used to study the specific heat capacity of the nanofluids. The specific heat capacity of pristine and functionalized CNTs mixed with water was found to be significantly higher than of the pure water by 10% and 45% respectively. The results of the heat transfer of the nanofluids increased suddenly with the increasing the concentrations of both pristine and functionalized CNTs. It can be concluded that the functionalizing CNT with Polyethylene glycol enhanced the dispersion of the CNTs and increased their heat capacities. The viscosity of the nanofluids was found to be dependent on the concentration of CNTs in solution. The pressure drop of the nanofluid compared with that of pure water was almost unchanged resulting in no extra pumping energy penalty.The authors would like to acknowledge the support provided by King Abdulaziz City for Science and Technology (KACST) through Science & Technology Unit at King Fahd University of petroleum & Minerals (KFUPM) for funding this work through project No: 09-NAN758-04 titled “Experimental Investigation of Heat Transfer Characterization for CNT-Nanofluid in Heat Exchangers” as part of the National Science Technology and Innovation Plan (NSTIP)

Enhanced thermal conductivity and reduced viscosity of aegirine-based VR/VGO nanofluids for enhanced thermal oil recovery application

The depleting of the available conventional energy supplies together with an industrial shift towards unconventional resources like heavy oil/bitumen has become more pronounced. The steam-based heating methods are primarily used by the oil industry for the heavy oil/bitumen recovery. However, the thermal recovery methods are energy-intensive and have limited applications, especially for both thin and deep reservoirs. Therefore, there is a high priority need to investigate alternative approaches. To date, the most progressive alternative technique that has proven its potential during pilot-plant tests is nanocatalytic in-situ heavy oil/bitumen upgrading via hot-fluid injection. Hence, the continual improvement of this technique is of utmost importance. This study aims to propose a new injecting nanofluid system suitable for high-temperature injection into the reservoir with consecutive heavy oil/bitumen upgrading and recovery. Here we report a new type of copper-based nanofluid using a blend of vacuum gas oil (VGO) and vacuum residue (VR) as the mother solvent. The nanoparticles were prepared by low-temperature hydrothermal synthesis route. Their detailed surface, morphology and size characterizations were achieved by X-ray diffraction, dynamic light scattering and scanning electron microscopy. The stable nanofluids were prepared by dispersing copper-based nanoparticles in a mixture of VGO and VR, at different ratios and temperatures. A set of measurements to determine the thermal conductivity and viscosity of the nanofluid with different loading of nanoparticle were performed. The thermal conductivity values of nanofluid systems are substantially higher than that of the base fluids. The nanofluid for 2 wt% of copper-doped aegirine nanoparticles dispersed in VGO and VGO/VR mixture exhibits a maximum thermal conductivity of 20% and 24%, respectively. It was found that the thermal conductivity of nanofluids increases with decreasing the hydrodynamic particle size. Moreover, the presence of chemo-physical interactions between nanoparticles and base fluid further enhances the thermal conductivity. Also, the temperature augmentation in a range from 80 to 110 °C exhibited a positive effect on thermal conductivity enhancement of vacuum residue-based nanofluid system. This particular nanofluid may find potential applications in enhancing heavy oil upgrading and recovery

Heat transfer enhancement of nanofluids using iron nanoparticles decorated carbon nanotubes

Enhancing heat transfer in thermal fluid systems can contribute significantly towards the improvement of thermal efficiency resulting in reducing energy consumption and hence carbon emission. Conventional fluids like water and oil have limited heat transfer potential. The need for the development of new classes of fluids with enhanced heat transfer properties is thus becoming essential. Many studies have developed nanofluids using nanoparticles, however, they showed a limited enhancement in heat transfer. This study investigated the heat capacity, enhancement of heat transfer, viscosity, and pressure drop of nanofluids with carbon nanotubes (CNTs) and CNTs doped with iron oxide nanoparticles (Fe2O3-CNT). The surfaces of carbon nanotubes were doped with 1 wt.% and 10.0 wt.% iron oxide nanoparticles. The pristine and doped CNTs were used to prepare heat-exchange nanofluids with additive concentrations of 0.01, 0.05, and 0.10 wt.%. A shell and tube heat exchanger was used to evaluate the overall heat transfer coefficient and the associated pressure. The specific heat capacity of the nanofluids was measured by differential scanning calorimetry (DSC). The results showed that the specific heat capacity of the nanofluids with undoped and doped CNTs is significantly higher than that of pure water by about 10% and 55%, respectively. The heat transfer rate of the nanofluids increased sharply with the CNT dosage the iron nanoparticles loading and reached up to 55% enhancement with doped CNTs. We observed that the power required to exchange 1.8 kW heat using nanofluid containing 0.1 wt.% of 10 wt.% Fe2O3-CNTs was 20 times lower than the power required to exchange the same amount of heat using water. This is because the iron nanoparticles enhanced the dispersion of the CNTs and increased their heat capacity and thermal conductivity. Compared with that of pure water, the encountered pressure drop of the nanofluid at the same flow rate was almost unchanged, resulting in no extra pumping energy penalty.The authors would like to acknowledge the support provided by King Abdulaziz City for Science and Technology (KACST) through Science and Technology Unit at King Fahd University of Petroleum and Minerals (KFUPM) for funding this work through project No: 09-NAN758-04 titled Experimental Investigation of Heat Transfer Characterization for CNT-Nanofluid in Heat Exchangers as part of the National Science Technology and Innovation Plan (NSTIP).Scopu

Managing European Cross Border Cooperation Projects on Sustainability: A Focus on MESP Project

International cooperation is a must to achieve the goal of sustainable development, since only through cross border actions’ complex issues like environmental degradation can be faced. Supranational initiatives and shared objectives are the only path for getting a durable and effective green strategy, which transcends boundaries or governments and fosters a common effort for sustainability through networking. The European Neighborhood and Partnership Instrument (ENPI) aims at reinforcing cooperation between the European Union (EU) and partner countries’ regions placed along the shores of the Mediterranean Sea. To this extent, MESP (Managing the Environmental Sustainability of Ports for a durable development) can be considered as a typical cross border cooperation project, willing to create a sustainable environmental management of port in northern and southern shores of the Mediterranean basin. This has been achieved through the development of specific guidelines towards environmental sustainability and the collection of common tools, methodologies, good practices and innovations focused on pollution reduction that can be replicated in Mediterranean ports and further. This was possible through the creation of a strong cooperation network and long-lasting collaborations among partners and stakeholders such as harbour cities, port authorities, universities, research centres and scientific skills