Finned tubes are widely used in the convection sections of industrial furnaces to enhance heat transfer efficiency. However, their service life can be limited by thermal, mechanical, and chemical degradation mechanisms, particularly in high-temperature environments where dissimilar materials are employed. This paper focuses on the investigation of finned tube failures observed in the convection section of the dehydration furnace (Unit 104). The tubes were manufactured from ASTM A106 Grade B carbon steel, and the fins from AISI 304 stainless steel. To identify the root causes of failure, several experimental techniques were employed, including optical microscopy, Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and corrosion testing in accordance with ASTM A262-15 (2021) Practice A. Visual inspections revealed multiple cracks on both tube and fin surfaces. The analyses indicated that sulfide formation on fin surfaces, welding imperfections at the fin–tube interface, and differences in heat transfer coefficients between the two materials contributed to uneven thermal distribution and crack initiation. Furthermore, microstructural examination revealed chromium carbide precipitation and sensitization along grain boundaries in the fin material. The combined effects of these factors promoted crack propagation from the fins into the tube wall, ultimately leading to leakage and fire hazards.
An end-of-pipe technology for processing oily sludge using a hydrocyclone is modeled in this study and then compared with an end-of-pipe technology using centrifugation with a science filter treatment system. The end-of-pipe technology design is proposed based on the characterization of physical and chemical data of oily sludge obtained from a national refinery in Port Harcourt, Nigeria. The aliphatic and aromatic hydrocarbons in the sludge, its metallic components, and water content were characterized using gas chromatography. The ChemCad software is used for computer model simulation of the end-of-pipe system (hydrocyclone and compartment separator) stream flow. The results show that the solids in the underflow from the cyclone contain about 3.8% by mass of hydrocarbons and 4.06% by mass of water. The hydrocarbon content of the hydrocyclone overhead recovered via the component separator bottoms is 97.9%, 1.5%, and 0.9% by mass of hydrocarbon, water, and solids, respectively. The ChemCAD software is used to process laboratory results and simulate stream flow designs. End-of-pipe (centrifugation) filter technologies for sludge treatment are designed for 75% optimal oil recovery, with zero solids and water content in the recovered oil, making it a high-quality product largely due to the filtration system incorporated. The high oil recovery of 97.9% and the low carbon footprint in our proposed end-of-pipe technology model may be attributed to the use of a natural hydrocarbon solvent (kerosene) to process the sludge in a hydrocyclone and separation compartment, which enhanced oil extraction and recovery.
This study explored the photocatalytic degradation process for treating industrial spent caustic wastewater, focusing on reducing chemical oxygen demand (COD). Cu(BDC)/MgO nanocomposites were synthesized via microwave-assisted synthesis and served as efficient photocatalysts. An artificial neural network (ANN) model was developed to estimate COD concentrations and optimize treatment parameters, aiming to achieve superior COD reduction. The research aimed to minimize the hydrogen peroxide-to-COD ratio and to optimize other factors influencing COD removal. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) elemental mapping. Optimal parameters for achieving a 97.55% COD removal efficiency were identified as a nanocomposite dose of 1.30 g/L, an H2O2/Spent caustic wastewater ratio of 1.50 ml/L, a pH of 3.0, a treatment time of 35 min, and an aeration flow rate of 2.50 L/min. Catalyst recycling studies demonstrated the exceptional recyclability and stability of the Cu(BDC)/MgO nanocomposites, showing they could be reused as catalysts even after five treatment cycles. This highlights the potential for prolonged and sustainable use of these nanocomposites in wastewater treatment processes, effectively reducing COD levels in spent caustic effluents.
Biodiesel is a major renewable energy source derived from vegetable oils. Modern techniques are now required to produce biofuels, particularly biodiesel, to improve the efficiency and sustainability of the process. This study focuses on continuous biodiesel production from waste cooking oil via microwave-assisted transesterification in a flow process. Calcium oxide prepared from willow leaf extract was used as a catalyst at concentrations ranging from 1% to 4%, with a microwave power of 20% of the total 800W and an irradiation time of 0.5-7 min. The oil-to-methanol ratio was 50wt.%- 80wt.%, and the reaction temperature was 45-75 ℃. The results revealed that the waste cooking oil can be converted to biodiesel with a yield of (93.43%) in 5 min. with a 70wt.% oil/methanol molar ratio and 3wt.% catalyst. Also, the results indicated that the production of high-quality biodiesel, in accordance with ASTM standards, was facilitated under all operational conditions. The results suggest that microwave heating is a viable approach for achieving high biodiesel yields with shorter reaction times, even in continuous reactions. This is attributed to reduced energy activation. This method is promising for industrial-scale production of high-quality biodiesel, with methanol as the preferred alcohol.
The method involves a sample preparation technique through microwave digestion to extract eight metals (Si, Al, Mg, Ca, Fe, Na, K, and Ti) in Portland (SRM 1888b) and Blended (SRM 1881a) cement traceable to NIST, followed by spectrometric detection and quantitation via the simultaneous system inductively coupled plasma-optical emission spectroscopy (ICP-OES). A 0.2-gram sample of the materials was prepared for closed-system digestion at 1200W. After digestion, solutions were diluted in 50-mL dedicated polypropylene laboratory ware (volumetric flasks) and analyzed. Accordingly, the dilution and calibration patterns were determined. The analyses were performed in five replicates. The detections of Si, Al, Mg, Ca, Fe, K, and Ti following radial mode and Na via axial torch orientation gave satisfactory results. Reproducibility studies were conducted, and ICP-OES configurations were established for each element. The method was developed based on its figures of merit. The procedure was validated with exceptional performance, except that it was not robust at a higher sample mass. Operational maintenance procedures were established when many samples were run. Measurement uncertainty estimation is recommended to identify the sources and effects of measurement errors.
This study investigates the independent effects of microwave irradiation and acidic solutions on wettability alteration and hydrocarbon desorption in carbonate reservoir rocks. Contact angle measurements and ATR-FTIR spectroscopy were employed to analyze both surface wettability changes and molecular-scale modifications. Microwave treatment at 780 W and 1300 W reduced the contact angle from an initially oil-wet state of ~132° to 72° and 69°, respectively, indicating a pronounced shift toward water-wet conditions. FTIR analysis confirmed these observations, showing decreases in the Polar/Aliphatic and Aromatic/Aliphatic indices, which reflect the desorption of polar and aromatic compounds from the rock surface. Acidic solutions produced similar effects, although their efficiency depended on brine composition. Hydrochloric acid in deionized water reduced the contact angle to ~57°, whereas seawater and formation water showed weaker changes due to ionic buffering by Ca²⁺ and Mg²⁺. The novelty of this work lies in separating microwave and acid effects, thereby demonstrating distinct mechanisms. Microwave irradiation enhances desorption via dielectric heating and bond disruption, whereas acidic solutions primarily act through chemical reactivity and ionic competition. These findings show that both methods independently promote wettability alteration, with efficiency governed by microwave power and brine chemistry. The results provide practical insights for the design of advanced Enhanced Oil Recovery (EOR) strategies, including microwave-assisted stimulation and optimized acidizing treatments in carbonate reservoirs.
During the current period of decline in oil and gas production in the Cuu Long Basin, it is necessary to evaluate a typical reservoir. One of the important geometrical reservoirs is the thin-bed reservoir. To determine the presence and evaluate the potential of thin-bedded reservoirs, well logging data are normally used. At Well X in the Cuu Long basin, the distribution of Gamma Ray values (histogram), log curves from well logging techniques, and geological analysis are used to calculate the percentages of sand and shale. Based on these results, thin-bedded reservoirs will be recognized. In this study, the sand percentage ranges from 40% to 60% (equivalent to a shale percentage range of 60% to 40%), indicating the presence of thin-bed layers. Porosity and permeability tend to decrease with increasing depth, particularly when moving from the Lower Miocene formation to the Upper Oligocene formation.
Emulsion is a critical problem in the oil and gas industry, from production through refining. It must be prevented or treated by the oilfield operator to ensure that the crude oil meets API standards. Emulsions can be oil-in-water, water-in-oil, or multiple emulsions, and require crude oil, water, an emulsifying agent, and emulsifying conditions. Several approaches, including mechanical, thermal, electrical, and/or chemical, are used to manage emulsions in the oil and gas industry. Still, the chemical approach is most widely used due to its technical, economic, and environmental viability. The chemical demulsification technique involves adding chemicals to break the bonds between brine and crude oil, using mechanisms such as flocculation, coalescence, and sedimentation. Several demulsifiers are available, but these chemicals are expensive for developing countries and are not environmentally friendly. In this study, a comprehensive review of the demulsification performance of locally formulated demulsifiers was conducted. Based on the study's results, a comprehensive understanding of the emulsion formation concept, mechanism, and types is necessary for designing a suitable demulsifier. Nicotiana Tabacum recorded 73.33% efficiency, orange peel recorded 60% efficiency, while soya bean husk oil recorded 45% efficiency in demulsification. Camphor, Vegetable Oil, Alum, and Liquid Soap were identified as key ingredients in the formulation of a local demulsifier, each playing a distinct role. Speed and Temperature increase the demulsification of locally formulated demulsifiers. The demulsifier performance of the locally formulated demulsifiers can be optimized using software.
This study investigated the enhancement of biodiesel yield from sunflower oil via transesterification using a zinc oxide (ZnO) nanocatalyst under ultrasonic irradiation. The properties of the nanocatalyst prepared by the sol-gel method were characterized by XRD, FTIR, SEM, and TEM analyses. The ZnO nanoparticles had an average size of 24 nm with a hexagonal, slightly spherical structure. Response Surface Methodology (RSM) and Central Composite Design (CCD) were applied to evaluate the effect of influential parameters on methyl ester yield. Besides, the accuracy of the suggested model was confirmed by Analysis of Variance (ANOVA). A reasonable accordance between the experimental and predicted data was achieved with R² = 0.9968 and adjusted R² = 0.9938. The optimum process conditions were a methanol/sunflower oil molar ratio of 10.98 mol/mol, an ultrasonic time of 26.28 min, and a nanocatalyst loading of 2.71 wt.%. Under these conditions, the RSM model predicted a maximum biodiesel yield of 90.5%, while the highest experimental yield was 89.57%, confirming the model's accuracy. Moreover, FTIR analysis of the produced biodiesel confirms successful synthesis. The nanocatalyst demonstrated high reusability over seven cycles, maintaining a biodiesel yield above 80% throughout, indicating excellent recyclability. Therefore, this research demonstrated that the combination of ultrasonic radiation and ZnO particles presents a promising approach for biodiesel production, enabling high efficiency within a short reaction time.
This study presents a detailed investigation into the presence, toxicity, and remediation of polycyclic aromatic hydrocarbons (PAHs) in petroleum refinery environments, with a focus on the Dora Refinery in Baghdad, Iraq. PAHs, known for their carcinogenic and mutagenic effects, were assessed through seasonal air and water sampling during summer and winter. GC–Mass Spectrometry and high-volume air samplers were used to quantify major PAHs, with notably higher concentrations observed in summer; chrysene reached 485 ppm due to increased volatility. To mitigate contamination, adsorption experiments were conducted using palm-derived fiber (DPF) and activated carbon (AC). Characterization by BET, FTIR, and SEM confirmed the adsorbents’ microporous structure and the presence of functional groups favorable for PAH capture. Optimal conditions included temperatures of 30–35 °C, a neutral pH, and a contact time of 15–30 minutes. The highest removal efficiencies were for benzo[a]pyrene (95%) and naphthalene (92%). Adsorption data best fit the Langmuir isotherm (R² = 0.9683), indicating monolayer adsorption. The Freundlich and Temkin models showed lower correlation. The findings demonstrate the potential of eco-friendly, low-cost adsorbents in refinery zone remediation. The study underscores the importance of stricter emission regulations, ongoing environmental monitoring, and sustainable remediation technologies to mitigate PAH-associated health and environmental risks.
As conventional oil and gas supplies are becoming depleted, the need to reduce the viscosity of heavy crude oil has become increasingly significant. This work aims to clarify the mechanism of viscosity reduction in heavy crude oil using a new method: microwave irradiation assisted by okra powder nanomaterial. For this purpose, two setups are designed. The first setup was designed to measure the effect of prepared okra powder (1030.6 nm) on heavy crude oil, with the aim of determining optimal conditions for flowability enhancement. The second setup was designed to show the effect of electromagnetic heating on viscosity reduction. To investigate the microstructure, effective functional groups, and particle size distribution of the prepared powder, Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray Spectroscopy (EDX), a Particle Size Analyzer (PSA), and Fourier Transform Infrared Spectroscopy (FTIR) were used. For the first setup, the results showed that the optimum conditions were achieved at 100 ppm addition, with a viscosity of 19.21 cP. Whilst for the second setup, at a power of 800 Watts and 4 min treatment time, the viscosity reduced to 17.52 cP, while with the use of both nano biomaterial and electromagnetic heating, the reduction achieved was 15.02 cP, which shows the high effectiveness of the electromagnetic heating mechanism on preserving low viscosity and improving flow characteristics even at moderate temperatures. This indicates a viscosity reduction of around 28.68%.
Water pollution from industrial waste, toxic biological waste, and crude oil refining wastewater: All of these pollutants are released into the environment and pose a major problem today due to their toxic organic and inorganic contaminants. The study found that two electrical methods, electro-coagulation (EC) followed by electro-oxidation (EO) and electro-oxidation alone, effectively reduced organic phenol (C₆H₅OH) levels in oil-refining wastewater from Najaf refineries in Iraq. Both methods achieved remarkable success, though with differences in the factors affecting dissolved phenol removal. The work was done using aluminum and graphite electrodes as the cover of the electric cell and steel (SS) electrodes as the cathode of the cell, made of resistant plastic, in the first method, and graphite electrodes as the anode of the cell with steel (SS) electrodes in the other method. The initial concentration of phenol in the treated water was 50 ppm under the following conditions for both methods: electric current density of 10, 15, and 20 mA/cm², sodium chloride (NaCl) with concentration of 0, 1.5, and 3 g/l, and acidity of 3, 7, and 10 pH, with a fixed time of 1 hour for the EC process and 2.5 hours for the EO process for the first method, while in the other method, the time was varied from 2-4 hours. The results showed that the removal rate was directly proportional to the high current density and NaCl concentration under mild acidic conditions for the first method, with the optimum conditions for the removal process being a current density of 20 mA/cm2, pH 7, and a NaCl concentration of 3 g/L. A removal rate of 95.05% was achieved for the first method under the aforementioned conditions. The results for the removal rate in the second method were obtained under the following conditions: a current density of 15 mA/cm2, a pH of 3, a NaCl concentration of 3 g/L, and a time period of 3 hours. A removal rate of 96.3% was achieved under the mentioned conditions. Optimization tests were performed using the response surface methodology with Box-Behnken design to identify key operational factors influencing phenol removal from wastewater.
This research aimed to study the effect of hydrothermal carbonization (HTC) process constraints like reaction temperature and contact time of the hydrochar produced via conversion of spent waste tea (SWT), at the time of removing the environment of the pollutant SWT, then to study the hydrochar produced by the HTC process. At the range of temperatures, the SWT feed amount was 5 g, 2 MPa N2 pressure, with a constant contact time of 45 min, with various temperatures of 150, 175, and 200 °C, respectively. At the range of residence times, the 5g of SWT, 2 MPa N2 pressure, at constant temperature at 200 °C (the finest degree it was found), and the various contact durations at 30, 45, and 60 minutes, respectively. The characterization process was carried out via physical properties, higher heating values (HHVs), proximate and ultimate analysis, energy recovery (ER), and energy yield (EY). The results showed that the SWT reached carbon contents and the highest HHV. The conversion of SWT by the HTC process could be used as a solid carbon fuel for energy generation and to rid the environment of pollutant materials.
Ultrasonic waves have emerged as a transformative technology in enhanced oil recovery (EOR), offering solutions to critical challenges such as low recovery efficiency, reservoir heterogeneity, and high operational costs. This review explores the principles, mechanisms, and applications of ultrasonic waves in oil recovery, highlighting their ability to reduce interfacial tension, improve fluid mobility, and enhance reservoir permeability. Key findings from case studies indicate that ultrasonic-assisted EOR can increase recovery rates by up to 60%, reduce chemical dependency, and lower environmental impact compared to conventional methods. The primary objective of this review is to synthesize existing research on ultrasonic wave applications in EOR, identify gaps in knowledge, and propose pathways for future advancements. Methodologies analyzed include laboratory-scale experiments, field applications, and modeling studies that evaluate the effects of ultrasonic parameters such as frequency, amplitude, and power density on recovery performance. By providing a comprehensive understanding of ultrasonic-assisted oil recovery, this study underscores its potential to revolutionize hydrocarbon production, especially in challenging reservoirs. Future research directions include optimizing ultrasonic parameters for specific reservoir conditions and integrating this technology with hybrid recovery methods for enhanced efficiency and scalability.
Most of the reservoirs in Iran are carbonate reservoirs that spend the second half of their life cycle, requiring acid stimulation processes for improved production rates. Acidizing is a well and reservoir stimulation method used to increase oil and gas production from the fields due to its cost and efficiency. Acidizing of carbonate reservoirs is usually done in three stages: pre-flush, main acidizing, and post-flush. The pre-flush fluid is used to change the wettability of the rock from oil-wetting to water-wetting. In this work, we aim to identify the optimal pre-flush fluid using a CTAB surfactant to enhance the acidizing process. Initially, the porosity test is conducted on the carbonate cores, and then they are acidized using 15 wt% HCl. Then, the contact angle test is performed to determine the optimal concentration of surfactant and the optimal time. Finally, the cores that we placed in contact with the pre-flush fluid were positioned in the vicinity of the acidic solution to assess the effectiveness of the pre-flush fluid. A CTAB surfactant solution with a concentration of 500 ppm in seawater, and a duration of 120 minutes, reduced the contact angle from 125 to 42.574, and was determined as the optimal pre-flush fluid. Also, the combination of 15 wt% HCl with seawater had the best performance.
Transporting heavy crude oil from the wellhead to the oil refineries. It is essential because worldwide oil production is on the rise. These oils are characterized by high viscosity and low API gravity. Due to these specifications, the flow of oil through pipelines is complex, and to facilitate its transportation, it must be treated. In this paper, the additives that reduce the viscosity and density of crude oil and reduce the asphalt materials in it, which, if their percentage increases, are deposited in the transport pipelines. Additives are not only to reduce the viscosity and density of heavy oils, but their use aims to reduce the content of asphalt and sulfur materials and as a result of all this friction and pressure losses between crude oil and pipes will be reduced during transportation, with a decrease in viscosity and density of crude oil will increase its movement, and with a reduction in sulfur content will reduce corrosion that causes severe damage to pipes. Solvents (such as naphtha, toluene, gasoline, and kerosene), surfactants (including petroleum sulfonates and polymeric surfactants), and nanoparticles (like Al2O3 and Fe2O3) are the key additives that enable this enhancement and optimization for the transportation of crude oil through pipelines. One of the essential additions that improves heavy crude oil is the addition of solvents with low viscosity and density. These solvents reduce the viscosity of heavy crude oil, decrease the proportion of metals such as nickel and vanadium, and lower the sulfur content in crude oil.
Hydraulic fracturing is among the most extensively utilized techniques for enhancing hydrocarbon production in oil and gas wells, primarily by creating high-permeability, conductive flow pathways that improve the well’s productivity index. This study examines key factors influencing hydraulic fracturing performance, with a particular focus on formation damage, fluid selection, and proppant optimization. Reservoir characterization was conducted using log data, enabling the division of the reservoir into three distinct zones based on their petrophysical and geomechanical properties. The effects of fracturing fluid composition, proppant type, and density on fracture performance were systematically investigated. Critical input parameters, including well completion type, fluid properties, bottom-hole pressure, and temperature, were utilized to simulate the hydraulic fracturing operation using advanced modeling tools. The simulation process evaluated user-controlled variables such as fluid type and volume, proppant characteristics, pump scheduling, and fracture geometry. Through iterative optimization, the study identified an optimal hydraulic fracturing design comprising 12 pumping stages. This included the use of PrimeFRA fluid in the pad stage, YF550HT fluid in the main fracturing stages, and a 2% KCl solution for flushing. The resulting fractures exhibited an optimal length and width of 388 ft and 0.02 ft, respectively. These findings underscore the critical role of simulation in designing and optimizing hydraulic fracturing operations for enhanced reservoir performance.
Pharmaceutical contamination of aquatic environments poses a significant threat to ecosystems and public health. Rifampicin, a first-line antibiotic used to treat tuberculosis, is often detected in wastewater, contributing to antimicrobial resistance and toxicity to aquatic organisms. In this study, the biosorption potential of live and dead Chlorella for the removal of rifampicin under batch conditions was investigated. Several parameters of dead Chlorella were evaluated to select the optimal conditions for the removal process. The optimal pH was 4, at which the maximum adsorption capacity, q max, was 58 mg/g. The optimum temperature was also tested, and it was found that 25 °C yielded the best result, with a maximum adsorption capacity of q max = 65 mg/g. The contact time, initial rifampicin concentration, and algae biomass dosage were systematically studied to determine their effect on the removal efficiency. The results showed that live Chlorella exhibited much higher adsorption capacity than dead Chlorella. These results suggest that the inactive microalgae biomass could be an effective and environmentally friendly bioadsorbent for treating antibiotic-contaminated wastewater.
Insulating paper aging of power transformers, a reliability factor for this equipment, can be evaluated by non-destructive methods such as measuring chemical markers' content in transformer oil. Since the sampling temperature of oil can affect the accuracy of laboratory measurements, the correlation between novel aging marker methanol and the degree of polymerization (DP) of insulating paper has been studied in this study. Temperature correction factors have been obtained for the markers (2-Fal, water, and methanol), and the under-load transformers' data has improved the correlation formula. Sampling from a real transformer was carried out to optimize the calculated estimation formula. Various experiments have been performed on them, and their results have been analyzed. The real DP was also measured for the insulating papers sampled at the overhaul stage. The optimized model for insulating paper DP calculation using a temperature-corrected concentration of methanol in insulating oil has been provided in this work.
Electrospun NiMo/Graphene composite nanofibers (NMGF) and NiMo nanofibers supported on Graphene nanosheets (NMFG) were prepared via the electrospinning technique. Their performance for the hydrocracking of n-hexadecane (n-C16) was compared with the NiMo/Graphene (NMG) synthesized by the conventional impregnation method and commercial NiMo/γ-Al2O3 (NMA) catalysts in a fixed-bed reactor. ICP, BET, TEM, FESEM, XRD, and NH3-TPD tests were used to characterize the produced catalysts. The performance of the catalysts was evaluated based on total conversion and the distribution of liquid products over a continuous reaction period of 120 hours. The uniform dispersion of fibers, high surface area, large pore volume, and stronger acidic sites of NMGF and NMFG catalysts resulted in high percentage conversions of 99.5 and 99.2, respectively. The lighter hydrocarbons were achieved in hydrocracking using nanofibrous catalysts. Furthermore, nanofibrous catalysts produced a more stable catalyst than their counterparts, which suffered from coke production and deactivation of roughly 6% over 120 hours. The obtained results revealed the high potential of fibrous catalysts synthesized via the electrospinning method compared with conventional metal oxide nanoparticles-supported catalysts for hydrocracking heavy oils.
