Iranian Journal of Oil and Gas Science and Technology

Abstract In this study, acid oil, which is a by-product of oil refinery waste was used for acid-catalyzed esterification to produce biodiesel. The reaction variables were methanol: acid oil molar ratio (1:1, 5:1, and 10:1), catalyst concentration (1%, 2%, and 3%), and reaction time (5, 30, and 60 min). Conversion yield, mass yield, free fatty acid (FFA) content, and physical properties (viscosity, density, refractive index, color attributes) of all the biodiesel samples were investigated. With increasing the methanol: acid oil molar ratio, catalyst concentration, and time, conversion yield and density increased, while free fatty acid content, viscosity and refractive index decreased, displaying an asymptotic trend toward equilibrium. At methanol: acid oil molar ratio of 10:1, catalyst concentration of 3%, and reaction time of 60 min, a near-maximum conversion yield of 95.3% was achieved. These conditions were considered optimum practical conditions, balancing biodiesel yield with operational and economic feasibility. Final yield of produced biodiesel at the practical optimum condition was 84.25%, which confirms that acid oil is a suitable feedstock for biodiesel production.

Abstract Understanding gas hydrate formation conditions is crucial for designing natural gas transmission pipelines. These compounds are studied from both thermodynamic and kinetic perspectives. Despite significant advances in the thermodynamic aspect of hydrates, kinetic investigations still demand further research. Accordingly, in order to determine the equilibrium conditions of natural gas hydrate formation, six independent experiments were conducted using natural gas samples from the NF unit of the Bandar Imam Petrochemical Complex. The tests were carried out in a fixed-volume reactor at temperatures of 278.3, 278.6, 284.8, 290.3, 279.3, and 280.6 K, and pressures of 37.8, 19.3, 28.4, 52.2, 32.7, and 16.2 bar, respectively. The experimental results showed that the mass transfer coefficients were 0.343, 0.236, 0.200, 0.314, 0.297, and 0.166 m/s, while the molecular diffusion coefficients were 2.5968 ×10^(-9), 6.2866×10^(-9), 3.3931×10^(-9), 1.49×10^(-9), 4.28×10^(-9), and 7.42×10^(-9) m²/s, respectively. These findings indicate that an increase in reactor temperature leads to a decrease in mass transfer coefficient and an increase in molecular diffusion coefficient, whereas an increase in pressure results in a rise in mass transfer coefficient and a decrease in molecular diffusion coefficient. These trends are consistent with established empirical correlations

Abstract Burning fuel oil presents a significant problem due to the harmful release of sulfur dioxide gases, which contribute to acid rain and environmental damage. Fuel oil contains a sulfur-rich asphaltene component, but the issues associated with burning this fuel oil can be mitigated through solvent deasphalting. This method isolates a portion of the asphaltene, thereby reducing the problems related to fuel oil combustion. In this study, the introduction of Nano-Fe2O3 into the fuel oil improved the efficiency of the solvent deasphalting process by up to 51% under optimal conditions (with a solvent-to-fuel oil ratio of 10 and a 5% weight percentage of Nano-Fe2O3). As a result, the sulfur content in fuel oil decreased from 3.5% to 2.71% by weight, reflecting a 22.5% reduction. Various analyses, including XRD, BET, FESEM, and FTIR, were used to examine the Nano-Fe2O3. Additionally, the Response Surface Method from Design Expert software was employed for statistical analysis and optimization. The experimental design included two numerical variables: the percentage of Nano-Fe2O3 (ranging from 1 to 5% by weight) and the solvent-to-fuel oil ratio (ranging from 5 to 10). The remaining sulfur in fuel oil and the efficiency of the asphaltene separation process were the dependent variables under investigation. Mathematical models were introduced to analyze these output variables, showing a high level of significance in predicting their behavior based on the independent variables, with predicted R2 values of 0.8218 and 0.9843, respectively.

Abstract This study examines and optimizes operational strategies in distillation units. Given rising energy costs, limited energy resources, and increasing environmental constraints, improving the energy efficiency of process industries has become critically important. This research aims to enhance the performance of distillation units by implementing dynamic process intensification, which involves alternating between two operational points with different concentrations. The study evaluates the use of Proportional-Integral-Derivative (PID) controllers and Model Predictive Control (MPC) to improve the efficiency of distillation columns. The results show that MPC controllers markedly enhance distillation performance compared to PID controllers. The findings further indicate that optimal periodic operation between the two operational points requires identifying the specific points and the time intervals during which the system should operate in each mode. This research demonstrates that using PID and MPC controllers to manage concentration transitions between operational points can dynamically improve the distillation of methanol and 1-propanol mixtures. As a result, energy savings of approximately 1.5% and 4.5% in the reboiler duty of the distillation column can be achieved without compromising product quality or throughput. Simulations performed in Aspen software validate these outcomes and underscore the positive effects of dynamic process intensification on distillation performance (Kister et al., 1992; Smith 2005).

Abstract Fourteen crude oil samples were collected from different oil fields in the southeastern region of Pakistan and analyzed for pH, density, kinematic viscosity, saponification value, distillation range, and fourteen metal ions (Ca, Cd, Cu, Co, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn) using standard analytical procedures in accordance with ASTM methods. The metal ions were quantified by air–acetylene flame atomic absorption spectroscopy. Substantial variation in physicochemical properties and metal contents was observed among the different oil fields. The concentrations of V, Fe, Ca, and Ni were higher than those of the other elements. The metal ion data were further evaluated using correlation coefficient analysis, hierarchical cluster analysis, and principal component analysis.

Abstract In recent years, the issue of burning fossil fuels and the resulting carbon dioxide (CO₂) emissions have become a major concern. Various methods, including the synthesis of dimethyl ether (DME), have been proposed to address this issue. DME is considered a clean and sustainable fuel and is being regarded as an alternative to fossil fuels that can help reduce the emissions of harmful pollutants. This study assesses the cost of coproduction of dimethyl ether and electricity from the CO₂ flue gas of power plants. Producing this alternative fuel can reduce the power plant’s fuel consumption and environmental impacts while generating electricity. A feasibility study was conducted to integrate CO₂ recovery and utilization units from the flue gas of power plants for the synthesis of DME fuel using economic calculations in both direct and indirect methods. The total capital cost of establishing a DME production unit  was 2% higher through the direct method than the indirect method, due to the higher cost of equipment. Further, the cost of raw materials and utility was about 19% and 78% higher in the direct method than the indirect method, respectively, increasing the annual cost of DME production in this method by 52%.

Abstract The formation of heat-stable salts (HSS), such as acetate, formate, oxalate, and thiosulfate, in gas-sweetening units creates various issues, including corrosion, high foaming, and reduced unit efficiency. This research aims to investigate eliminating heat-stable salts using an anion-exchange resin. The findings indicated that removing approximately 85% of acetate anion salt from an amine solution at a solution-to-resin ratio of 30 was feasible. Two adsorption models, Langmuir and Freundlich, were employed to analyze the equilibrium adsorption of acetate anion salt. The results indicated that the Langmuir adsorption isotherm aligned more closely with the data obtained from the acetate anion ion exchange process with the resin. Furthermore, it was determined that the maximum adsorption capacity for acetate onto the resin was 15 mg/g at a temperature of 25 °C. The impact of contact time during adsorption was examined using quasi-first-order and quasi-second-order kinetic models and an intra-particle model. The results indicated that the quasi-first-order kinetic model provided the best fit to the data, and equilibrium adsorption was achieved after approximately 70 min. Thermodynamic parameters were also investigated, revealing a ΔH value of –12.7370 kJ/mol, indicating an exothermic adsorption process. Based on the studies, utilizing the selected resin appears to be a suitable option for removing heat-stable salts.

Abstract This study investigated the effect of ethylene-vinyl acetate (EVA) as an inhibitor on wax appearance temperature (WAT) of crude oil in the Iranian oil field using the differential scanning calorimetry (DSC) method. The effect of EVA on the morphology of crude oil wax crystals was examined by a system equipped with an ocular microscope. The EVA inhibitor has an outstanding performance in reducing the wax appearance temperature of crude oil and prevents the crystallization process and the connection of the growing wax crystals to form a network structure by adsorbing on them. Adding 800 ppm of the EVA inhibitor caused the most significant decrease in the WAT of crude oil at a rate of 26.13 °C and formed smaller crystals and weaker structures at this concentration. Therefore, 800 ppm of the EVA inhibitor was selected as the optimal value.

Abstract Water can contain microorganisms and cause deposition and corrosion in cooling tower systems. Therefore, the water treatment of cooling towers is essential. Various biocides are used to remove bacteria and disinfect the water of cooling towers, and the most commonly used are sodium hypochlorite and chlorine compounds. This work examined two chlorinated water, namely hypochlorous acid and sodium hypochlorite, in two pilot and industrial cooling towers. The results of the experiments on the pilot tower showed that the performance of hypochlorous acid in the disinfection and removal of bacteria and microorganisms was excellent. The total bacterial count decreased from 10000 to less than 800 (cfu/mL) compared to sodium hypochlorite. The experiments were performed on the industrial cooling tower of an acetic acid unit for six months, in which pH, free chlorine, total bacterial count (TBC), and sulfate-reducing bacteria (SRB) were measured. The very high disinfection power of hypochlorous acid compared to sodium hypochlorite and its relatively lower pH level led to a significant reduction in the use of chemicals in the cooling tower. The experiments and TBC and SRB tests showed outstanding performance in using hypochlorous acid.

Abstract In Iran, power plants use liquid fuels such as heavy fuel oil (HFO) or mazut to prevent disruption in power generation. The high percentage of sulfur compounds in HFO and the lack of efforts to remove it, causing significant damage to the environment. The purpose of this research is performing a techno-economic analysis on the Hydrodesulfurization (HDS) process of HFO. The results showed that for removing 85% of sulfur compounds from HFO with a volume flow rate of 250 m3/h that includes 3.5% wt sulfur compounds, the total capital investment and the net production cost are 308.9 million US$ and 114.5 million US$/year, respectively. Besides, the sensitivity analysis indicates that with a 100% increase in the catalyst loading, the mass percentage of sulfur compounds in the HFO will be decreased by 15% more. Also, 6.4% and 32% will add to the total capital investment and net production cost, respectively. With a 100% increase in the gas to oil ratio, the mass percentage of sulfur compounds in the HFO will be decreased by 15.3% more. Also, 43.8% and 6% will be added to the total capital investment and net production cost, respectively. With a 100% increase in the pressure of the HDS process, the mass percentage of sulfur compounds in the HFO will be reduced by 20.75% more. Also, 43% and 6.75% will be added to the total capital investment and net production cost, respectively. Ultimately, with a 100% increase in the inlet temperature of beds, the mass percentage of sulfur compounds in the HFO will be reduced by 5% more. Among the effective operational parameters, hydrogen consumption has the greatest impact on net production cost and payback period, and the pressure of the Hydrodesulfurization process has the greatest impact on increasing the total capital investment of the process.

Abstract Gasoline obtained from the fractionation of indigenous natural gas condensate has low octane number (78) and is therefore of limited uses. Lead-based octane boosting and catalytic reforming are not the viable methods for many fractionation plants. This study was therefore aimed to develop an inexpensive conceptual alternative method for boosting the octane number of gasoline. Natural gas concentrated in methane having high octane number (more than 100) was absorbed in the gasoline to boost the octane number partially (86). Selective additives i.e. ethanol, tert-butyl alcohol, methylcyclopentane, toluene, iso-octane and xylene were blended first with the gasoline to aid the absorption of natural gas molecules. The loss of absorbed gas molecules from gasoline with the increase in temperature was also observed. It is therefore required to try for avoiding any increase in temperature in the finished gasoline. The developed conceptual method is promising. The findings of this simulation study would be useful for more studies towards the development of an affordable alternative method for fractionation plants for boosting the octane number of gasoline derived from natural gas condensate.

Abstract The separation of naphthenic acids from crude oil is difficult, and the presence of such materials in crude oil reduces its value. In this work, using catalytic esterification with methanol, naphthenic acids of crude oil were removed to reduce their harmful effects. SnO₂/γ-Al₂O₃ nanocatalyst was synthesized and used to convert naphthenic acids of crude oil in a fixed bed catalytic reactor. The nanocatalyst was characterized by the X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area techniques. The XRD revealed the formation of rutile SnO₂ on alumina, and the FESEM approved that the catalyst is comprised of nanoparticles with a diameter in the range of 50 to 90 nm. The BET indicated that the catalyst has a mesopore structure with a surface area of 213.4 m²·g^–1. The optimal conditions for the catalytic esterification process of naphthenic oil were determined. The temperature of the reduction of the total acid number (TAN) of crude oil ranged from 250 to 360 °C, and the TAN was reduced to less than 0.5 mg KOH/g in this temperature range. A methanol-to-oil ratio (M/O) of 2 wt %, a velocity space of 2.5 h^–1, a reaction temperature of 300 °C, and atmospheric pressure were selected as the optimal conditions for the removal of naphthenic acids. Under these conditions, 83% of naphthenic acids was removed. The study indicated that SnO₂/γ-Al₂O₃ could be a promising nanocatalyst for the reduction of total acid of crude oil under mild conditions.

Abstract A device is designed and constructed for measuring the equilibrium surface tension of water and a number of other solutions. The measured equilibrium surface tension of water, as a reference fluid, has good consistency with literature data. Moreover, the equilibrium surface tension of the aqueous solutions of surfactants and polymer composed of sodium dodecyl sulphate (SDS), Triton CG-110, dimethyl di-dodecyl-ammonium bromide (DDAB), and polyethylene glycol (PEG) with different molecular weights of 200, 300, 400, and 600, as well as that of the ternary solutions of SDS/PEG/water, Triton CG-110/PEG/water, and DDAB/PEG/water at 293.15 K and atmospheric pressure are measured. The equilibrium surface tension of the aqueous solutions of PEG 600 are measured at 296.15 K because PEG 600 is solid at 293.15 K. The measured data are compared with the predictions of thermodynamic models, and the results show that Redlich-Kister (RK) model has the lowest error in predicting the experimental data.

Abstract This study presents a robust and rigorous method based on intelligent models, namely radial basis function networks optimized by particle swarm optimization (PSO-RBF), multilayer perceptron neural networks (MLP-NNs), and adaptive neuro-fuzzy inference system optimized by particle swarm optimization methods (PSO-ANFIS), for predicting the equilibrium and kinetics of the adsorption of sulfur and nitrogen containing compounds from a liquid hydrocarbon model fuel on mesoporous materials. All the models were evaluated by the statistical and graphical methods. The predictions of the models were also compared with different kinetics and equilibrium models. The results showed that although all the models lead to accurate results, the PSO-ANFIS model represented the most reliable and dependable predictions with the correlation coefficient (R²) of 0.99992 and average absolute relative deviation (AARD) of 0.039%. The developed models are also able to predict the experimental data with better precision and reliability compared to literature models.

Abstract The current work investigates the performance of a single-stage, bench-scale system using a spray dryer to treat produced water. The produced water is generated in three large reservoirs of Ahvaz, Maroon, and Mansouri fields, which have different compositions but the same high total dissolved solids (TDS) and total organic carbon (TOC). The results of this study indicate that the newly developed bench scale rig is able to reduce the amount of TDS in the water produced in Ahvaz, Maroon, and Mansouri reservoirs to 98.78, 98.65, and 98.90, and TOC decreases the three types of the produced water to zero. Investigating the effect of independent parameters on the performance of this system using response surface methodology shows that the most effective parameters affecting the efficiency of the produced water treatment system are the entering carrier gas temperature (TGIT), the flow rate of the produced water (QL), the carrier gas flow rate entering the spray dryer (QG), and the atomizer pore size (d). Additionally, the optimal conditions are obtained as follows: TGIT = 113.7 °C, QL = 20.8 cc/min, QG = 59.9 m³/hr., and d = 0.03 mm.

Abstract Separation of nitrogen from a gaseous mixture is required for many industrial processes. In this study, the adsorption of nitrogen on zeolite 4A was investigated in terms of different adsorption isotherm models and kinetics. An increase in the initial pressure from 1 to 9 bar increases the amount of adsorbed nitrogen from 6.730 to 376.030 mg/(g adsorbent). The amount of adsorbed nitrogen increased from 7.321 to 40.594 mg/(g adsorbent) by raising the temperature from 298 to 333 K at a pressure equal to one bar; however, it then dropped to 15.767 mg/(g adsorbent) when temperature decreased to 353 K. Increasing the amount of the adsorbent from 1 to 4 g decreased the specific adsorption from 67.565 to 21.008 mg/(g adsorbent) at a temperature of 298 K and a pressure of 3 bar. Furthermore, it was found that the nitrogen adsorption experimental equilibrium data are consistent with Sips and Langmuir-Freundlich models. The highest overlap was achieved through second order and Ritchie’s models.

Abstract Several mesoporous nickel-based catalysts with MgO-Al₂O₃ as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating 10 wt.% nickel on the supports, the precursor was decomposed at several temperatures of 500, 600, 700, and 800 °C in order to elucidate the effect of calcination temperature on the physical and chemical characteristics of Mg-Al mixed oxides and the ultimate catalytic performance of the synthesized catalysts in the combined steam and dry reforming (CSDRM). The catalyst the precursor of which was calcined at 700 °C shows an excellent nickel dispersion and the highest activity among the other samples. It also exhibits the most stable performance during the long-term 36-hour run with high resistance against coke formation in the harsh condition of CSDRM.

Abstract In this work, the dispersed phase holdup in a Kühni extraction column is predicted using intelligent methods and a new empirical correlation. Intelligent techniques, including multilayer perceptron and radial basis functions network are used in the prediction of the dispersed phase holdup. To design the network structure and train and test the networks, 174 sets of experimental data are used. The effects of rotor speed and the flow rates of the dispersed and continuous phases on the dispersed phase holdup are experimentally investigated, and then the artificial neural networks are designed. Performance evaluation criteria consisting of R², RMSE, and AARE are used for the models. The RBF method with R², RMSE, and AARE respectively equal to 0.9992, 0.0012, and 0.9795 is the best model. The results show that the RBF method well matches the experimental data with the lowest absolute percentage error (2.1917%). The rotor speed has the most significant effect on the dispersed phase holdup comparing to the flow rates of the continuous and dispersed phases.

Abstract In this research, the effects of important parameters, including the molar ratio of acetic acid to sulfur(S) , sonication time, temperature, and hydrogen the molar ratio of peroxide to sulfur on the performance of ultrasound-assisted oxidative desulfurization were studied using the response surface method (RSM). To this end, a model fuel containing n-decane and dibenzothiophene at a concentration of 1000 ppm was used. It was found out that the temperature and acetic acid/S molar ratio were the most influencing parameters affecting the conversion of sulfur compound. The synergistic effects of the parameters were also investigated, and it was discovered that the maximum conversion of dibenzothiophene reached 98.59% when H₂O₂/S, acetic acid/S, temperature, and sonication time were set to 167, 330, 80 °C, and 30 min respectively. Finally, the apparent kinetics of dibenzothiophene oxidation and the activation energy of reaction were presented.

Abstract In the current work, a framework is presented for amine solvent selection in gas treating process. Since the appropriate decision making in this field affects the capital and operational costs, multi attribute decision making (MADM) techniques were used to rank alternatives. The determination of criteria and alternatives is the most important aspect in the MADM. Criteria were divided into two categories, namely physical and process, and twelve physical indexes and nine process indexes were detected. Mono-ethanol amine (MEA), di-glycol amine (DGA), di-ethanol amine (DEA), di-isopropanol amine (DIPA), and methyl di-ethanol amine (MDEA) are intended as alternatives. The importance of the criteria was expressed by weights, and the weights were determined by the analytic hierarchy process (AHP) method. The traditional Technique for Order Preferences by Similarity to an Ideal Solution (TOPSIS) method was applied to the physical criteria with crisp data. The modified interval TOPSIS technique was used to study the process criteria with interval data. The data of the criteria and alternatives were collected from Ilam Gas Treating Company, and the solution for sour gas sweetening was ranked by the proposed approach. Based on our computations, MDEA was defined as the best amine solvent with an average ranking of 1.5.

Abstract In sour gas flares,  content like any other components in inlet gas influences adiabatic flame temperature, which, in turn, impacts on the pollutant emission. Wherever flame temperature increases, the endothermic reaction between  and  is accelerated, which means higher  emission to the atmosphere. In this work, we developed an in-house MATLAB code to provide an environment for combustion calculations. Then, this written code was used to perform sensitivity analyses on  content, air temperature, and excess air ratio in sour gas flares. We used Environmental Protection Agency (EPA) reports to assign weighting indexes to each air contaminant according to its harmfulness to environment; thereafter, sour gas flaring conditions were optimized for two real field case studies, namely Ahwaz (AMAK) and South Pars, to reach the minimum integrated pollutant concentrations. The results show that each 2% increase in the  content of the entrance feed may produce 0.3% additional  in the exhaust. The results also confirm that decreases of 20 °F and 50 °F in the oxidant temperature cause  emission to reduce by 0.5% to 1% respectively. Finally, to verify and validate our results acquired from the written MATLAB code, FRNC 2012 industrial software was used to duplicate the oxidation results for the two sour flare case studies.

Abstract Dilution is one of the various existing methods in reducing heavy crude oil viscosity. In this method, heavy crude oil is mixed with a solvent or lighter oil in order to achieve a certain viscosity. Thus, precise mixing rules are needed to estimate the viscosity of blend. In this work, new empirical models are developed for the calculation of the kinematic viscosity of crude oil and diluent blends. Genetic algorithm (GA) is utilized to determine the parameters of the proposed models. 850 data points on the viscosity of blends (i.e. 717 weight fraction-based data and 133 volume fraction-based data) were obtained from the literature. The prediction result for the volume fraction-based model in terms of the absolute average relative deviation (AARD (%)) was 8.73. The AARD values of the binary and ternary blends of the weight fraction-based model (AARD %) were 7.30 and 10.15 respectively. The proposed correlations were compared with other available correlations in the literature such as Koval, Chevron, Parkash, Maxwell, Wallace and Henry, and Cragoe. The comparison results confirm the better prediction accuracy of the newly proposed correlations.

Abstract Packed bed reactors have many applications in different industries such as chemical, petrochemical, and refinery industries. In this work, the effects of some parameters such as the shape and size of particles, bed size, and bed length on the hydrodynamics of the packed beds containing three spherical, cylindrical, and cubic particles types are investigated using CFD. The effect of the combination of three particles types in a packed bed was also simulated. The simulation results show that flow channeling occurs in some parts of the bed which are not suitably covered by particles. It was also seen that flow channeling in the packed bed with cubic particles are more than those containing spherical and cylindrical particles. According to the CFD simulations, wake and vortex flows are created in all the beds, and the shape of particles affects these phenomena. The comparison of the pressure drop created in the packed beds indicates that the pressure drop in the packed beds having three particle types is lower than the packed beds containing only spherical, cylindrical, or cubic particles. Finally, the numerical results were compared with empirical correlations in the literature and showed good agreement.

Abstract In this work, new correlations are proposed to predict the products yield of delayed coking as a function of CCR and temperature based on the experimental results. For this purpose, selected Iranian vacuum residues with Conradson carbon residue (CCR) values between 13.40-22.19 wt.% were heated at a 10 °C/min heating rate and thermally cracked in a temperature range of 400-500 °C in a laboratory batch atmospheric delayed coking reactor for 2 hours. The amount of distillate (C₅₊-500 °C) and coke yield were measured in all the experiments, and the gas (C₁-C₄) product yield was calculated based on mass balance between products and feedstock in each experiment. According to the developed functions, products yield changes with CCR value linearly and is a power function of temperature. The further investigation of the results show that by a 1 wt.% increase in CCR value, the distillate yield decreases by about 2.1 wt.%, but the amount of coke and gas yields rise by 1.2 wt.% and 0.9 wt.% respectively.

Abstract The present study is about the reduction of humic acids (HA) by electrocoagulation (EC) method. Undesirable color, odor, taste, reacting with chlorine to produce toxic materials in water, and making a complex with heavy metal ions are some unfavorable environmental consequences of HA. Platinum and graphite as anode electrodes and platinum, titanium, and aluminum as cathode electrodes were used for this purpose. Also, solutions consisting of sodium sulfate (Na₂SO₄), as the electrolyte support, and humic acids at a concentration of 30 mg.l^-1 were used in the reduction tests. We investigated the best condition for pollutant removal at pH values of 3, 5, and 7 and voltages of 5, 10, and 18. The samples were taken during the electrolysis and were analyzed by the pH meter and UV-visible spectrophotometer. Moreover, the oxidation phenomena on anodes surface were studied by cyclic voltammetry tests. The results confirm that the Gr/Al electrodes by coagulation phenomena shows the best performance in the elimination of HA at an electrolyte support concentration of 0.02 molar after approximately 23 min at a pH of 7 and a voltage equal to 10 V.