Journal of Chemical and Petroleum Engineering
Volume:56 Issue: 1, Jun 2022

The growing fuel demands and drastic restrictions of politics on greenhouse gases emissions are motivating towards bioenergy research. In this paper, the yield improvement of the produced biodiesel from canola oil using transesterification process, in attendance of ZnO nanocatalyst and ultrasound waves, was investigated. The crystal size, morphology, and particle size of the prepared nanoparticles were recognized applying X-ray diffraction (XRD), scanning electron microscopy (SEM) and transverse electron microscopy (TEM) analyses, respectively. The size of ZnO nanoparticles was 45 nm with a hexagonal-shaped structure. The response surface methodology (RSM) and the Box Behnken design (BBD) were employed to analyze the impact of the independent variables on biodiesel production yield. The reliability of the proposed model was verified by applying the analysis of variance (ANOVA) with the objective of evaluating response. Regarding the yield, satisfactory accordance was obtained between the calculated and prognosticated data from RSM, with R2= 0.9910 and R2 adj= 0.9748. The optimum reaction conditions were acquired at methanol to oil molar ratio of 11.19:1 mol: mol, ultrasound irradiation time of 31.98 min, and nanocatalyst amount of 3.17 wt.%. The optimum value for the sono-biodiesel yield was achieved equal to 90.16%. Moreover, the kinetic study exhibited that the values of activation energy and Arnius frequency factor were achieved 46.23 kJ mol-1 and 5.83× 105 min-1, respectively. Accordingly, this research indicated that ZnO nanoparticles can be utilized as a promising and efficient heterogeneous catalyst for biodiesel production.

Relative permeability is a crucial input to reservoir simulators for modeling reservoir performance. Conventional methods of measuring relative permeability rely on either laboratory core-flooding experiments or fine-scale computer simulations. The former method is expensive and time-consuming, and the latter often does not represent the complex characteristics of existing systems. Data mining algorithms can be implemented to estimate relative permeability with reasonable accuracy for real applications without running laboratory or computer simulation experiments. This paper aims at presenting predictive correlations for relative permeability for carbonate rocks using data-driven approaches. To achieve this aim, a scatter plot matrix was applied to analyze 225 experimental datasets, including almost 3800 relative permeability data points (observations), for predicting relative permeability. Since relative permeability measures are often unavailable exactly at residual oil saturation and connate water saturation (known as endpoints); consequently, cubic equations were fitted and solved to precisely determine these points. Next, a symbolic regression algorithm was developed to predict relative permeability in different situations: when endpoints are available or unavailable and when the rock wettability is clear or not. For this purpose, all 225 datasets were divided into training and testing groups. The correlations were tested to predict testing data, which the symbolic regression algorithm has never seen before. Finally, the most accurate correlations were presented, and a detailed analysis was carried out. The results showed a good agreement between the real and the predicted data. The developed correlations proved to be very efficient in predicting the relative permeability accurately.

Polyacrylonitrile (PAN)-based carbon fibers were chemically modified with a different ratio of Sulfuric acid (SA) to Nitric acid (NA), then reinforced Polyurethane (PU) composites in the presence of carbon fibers were prepared. The structural and surface characteristics of the modified carbon fibers were investigated by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The FTIR results showed the presence of the carbonyl groups in a higher ratio of NA and the formation of carboxyl groups in a lower ratio of NA. The interaction between carbon fiber and PU matrix was studied by the dynamic mechanical thermal analysis (DMTA) method. The DMTA results showed with increasing carbon fiber/PU matrix interaction, the intensity of glass transition temperature decreased. Matching the DMTA results with the power-law model and Cole-Cole diagram showed that the process of carbon fiber modification can increase the amount of chain with a long relaxation time in the PU matrix.

The optimization of the operating pressure of the separators in the multistage crude oil production units has an undeniable effect on the quantity and quality of oil production. In this regard, the present study exploited a simulation-based approach to optimize a multistage crude oil production unit through determining the optimal separator pressure and number which maximizes the oil production rate, and operational flexibility while minimizing fixed and operating costs, and power consumption of the compressors. The decision-making process was performed for two cases in the National Iranian South Oil Company. The number of separation stages and their different arrangements were considered as the desired goals. According to the results, for the first case, maximum oil production can be achieved using these two-phase separators and one degasser tank, while the cold stripping method was recommended for the second case. Furthermore, economic evaluations were conducted by calculating the fixed initial investment and the total operating costs. The simulation results predicted the pressure of the production well in 2030 as 8.27 MPa. For the reservoir pressure of 7.58 MPa, the fixed project costs will be reduced by $11965307, while the oil production will decrease by about 20 barrels per day. It will result in a $58.4 million reduction in revenue over the next twenty years. Therefore, the optimal pressure of the reservoir was assumed to be about 6.89 MPa.

This paper investigates the effects of Fe/Ni ratio (0.5-2) and polyvinyl alcohol to total metal ratio (PVA/ (Ni + Fe) =0.5-1.5) on the performance of bimetallic(Ni-Fe) catalyst in dry reforming of methane. The activity, stability and H2/CO ratio of the catalysts are tested. The effects of both metal ratio and shell factor on the catalyst performance have been studied. The nickel-ferrite catalysts were prepared by sol-gel method. Shell factor is employed for controlling the size of the particles. The samples were characterized by XRD, BET, SEM, and TGA. The catalysts were tested at 800˚C in the microreactor with a feed ratio of CH4/CO2=1/1. The catalyst prepared with Fe/Ni=2 and PVA/ (Ni + Fe) = 0.5 ratio shows the best activity, and stability with 30 h time on stream. It can be attributed to NiFe2O4 as only available phase after calcination and smaller crystal size at the optimum values of Fe/Ni and PVA/ (Ni + Fe) ratio.

Recovery of propionic acid from aqueous solution is economically and environmentally important. In this study, the liquid-liquid equilibrium data of water + propionic acid + cyclic alcohols (cyclopentanol and cyclohexanol) ternary system was obtained at 303.2, 313.2, and 323.2 K temperatures. These ternary systems exhibit type-1 behavior of liquid-liquid equilibrium (LLE). The Hand and Bachman equations confirm the validity of the measured data. For correlation of liquid-liquid equilibrium data, the NRTL and UNIQUAC thermodynamic models have been used and the inter-molecular interactions coefficients have been determined. RMSD values for NRTL and UNIQUAC models in cyclopentanol containing systems were 0.0107 and 0.0057, respectively, for cyclohexanol 0.0108 and 0.0076 respectively, which showed the accuracy of these models in correlation liquid-liquid equilibrium data. The values of the selectivity factor for both solvents larger than the unit are obtained, which shows that these solvents can be used to extract propionic acid from aqueous solution.

Formic acid (FA) is used across the world for a wide variety of applications spanning from chemical production to textile and pharmaceutical industries. FA can be synthesized efficiently from the lignocellulosic biomass constituent carbohydrates by acid hydrolysis in a dilute aqueous reaction media. Since FA forms an azeotrope with water, its purification, water recycle and reuse are vital to establishing a cost-competitive process. In this study, the analytic hierarchy process (AHP) was implemented to determine the desired separation method for isolating FA from a 3 wt.% aqueous solution by considering the advantages and disadvantages of each process. Four parameters named as scalable, quality of the final product, repeatable, and energy consumption were defined as criteria to perform AHP analysis. Furthermore, six alternative approaches namely (i) azeotropic distillation, (ii) extractive distillation with a liquid solvent and (iii) solid salt, (iv) the combination of liquid solvent and solid salt, (v) pressure-swing distillation, and (vi) liquid-liquid extraction (LLE) were examined to decide the most preferred separation method with respect to the goal, which is the desired separation method. The AHP results indicated that the alternative approach, the LLE and the scalable criteria have the highest preference with 39.4% and 54% priority, respectively. The proposed process based on the alternative approach could extract 99% of FA by using diethyl ether. Moreover, an estimated minimum selling price (MSP) of 2.48 $/kg FA with 97.4% purity was achieved by using techno-economic assessment for a typical plant with 1715 ton/day capacity.

Due to high storage capacity, high dissociation enthalpy, and the appropriate melting point of gas hydrates, these compounds have a potential for many industrial applications. Tetra n-butylammonium halides are typical guest molecule involved in the formation of semiclathrate hydrates. In this manuscript, the dissociation enthalpy of methane/carbon dioxide/nitrogen + Tetra n-butylammonium Chloride semiclathrate hydrates is evaluated using the Clausius-Clapeyron equation. The equilibrium data are measured in a 460 cm3 stirred batch reactor using an isochoric pressure-search method. The dissociation enthalpy data were evaluated in the temperature range of (275.15 to 304.75) K and the pressure range of (0.36 to 10.57) MPa at (0 - 0.36) mass fraction of Tetra n-butylammonium Chloride. The results showed that the utilization of Tetra n-butylammonium Chloride increases the amount of dissociation enthalpy of semiclathrate hydrates per mole of the hydrated gas. By increasing the mass fraction of Tetra n-butylammonium Chloride, the amount of dissociation enthalpy per mole of hydrated gas increased.

Despite lots of researches on the transit-time and Doppler flowmeter technologies, few researches have been done on ultrasonic cross correlation flowmeter technology. Since the mechanism of the ultrasonic cross correlation flowmeter (UCCF) differs from other ultrasonic flowmeter technologies, it strongly requires individual investigations. The upstream straight pipe length is an important item that strongly affects the UCCF accuracy. Determination of proper calibration factor concerning upstream pipe length could incredibly improve the measurement precision. In the present study, the Computational Fluid Dynamics (CFD) simulation was conducted and the water flow inside a pipe without any flow disturbances (e.g., valve, fitting, or bend) was simulated to investigate the calibration factor for the UCCF at different upstream straight pipe lengths and different Reynolds numbers (from 76,600 to 383,400). For accurately predicting the turbulent flow behavior, Reynolds Stress Model (RSM) was used in this study. The results indicated that by increasing the upstream pipe length up to approximately 25 times pipe diameter, the required calibration factor decreases, then increases, and finally remains constant at lengths greater than 40 times pipe diameter. Eventually, a proper correction factor on the calibration curve was developed at different flow Reynolds numbers, for the first time, in order to modify the calibration curve at various upstream pipe lengths.

Effects of magnetic field strength and direction were studied on the fluidization of titanium oxide nanoparticles (anatase phase) with ferromagnetic iron (III) oxide nanoparticles. The main hydrodynamic structures were defined and studied using wavelet transform. Energy analysis was used to study the effect of the field direction and strength on fluidization. The results suggested that mesostructures (agglomerates) have the most effect on the nanoparticle fluidization characteristics. Higher energy at high field strength for upward direction, suggests more intense interaction between agglomerates in the bed for nanoparticles that result in more stochastic pattern and lower ABF regime characteristics. Downward direction at low magnetic field strength shows improving the fluidization quality by the effect of the vibration of the solenoid. It was observed that at low field strength, vibration has a major effect on fluidization than the magnetic force. At high magnetic field strength, as the magnetic force becomes stronger, the downward field decreases the energy of finer structure (agglomerates) which leads to less movement and resistance against fluidization.

Recent concerns about the greenhouse effect and climate change have been prominent worldwide. In this study, a single-step KOH activation was used to prepare Entada porous carbon adsorbent. The produced activated carbon was used for CO2 adsorption. Isotherm models including Freundlich, Langmuir, Dubinin-Rudeshkovich, Temkin, and Hill were used for adsorption isotherm data. In addition artificial neural networks were used for prediction of CO2 adsorption capacity. Trial and error helped us to find the best design, selecting the architecture with the lowest error (MSE) and the best regression coefficient. The best MSE validation performance of neural network was 0.00094486. The neural network model can effectively predict CO2 adsorption on activated carbon from Entada africana Guill. & Perr. Adsorption capacities of activated carbon from Entada africana Guill. & Perr at 273 k and 289 k and 1 bar were 4.34 mmol/g and 6.78 mmol/g, respectively. The Brunauer–Emmett–Teller specific area (SBET) and the microporese volume equated to 2556 m2/g and 0.78 cm3/g, respectively. Thus, Entada African Guill & Perr activated carbon shows promise in capturing CO2.

Achieving the rate and the amount of mass transfer is of paramount importance in selecting optimum conditions for drying and affects the development of the quality of drying. Note that, to obtain the amount of mass transfer, the conditions of mass transfer such as temperature, pressure, geometry, and diffusion coefficient should be completely determined. In this research, an experiment is conducted in atmospheric conditions and then the amount of mass flow in a spherical body is measured. Utilizing the Newman equation and the experimental results, the diffusion coefficient is found to be in the range of 10-11 m2/s. Additionally, the experimental data reveal the linear and exponential variation of diffusion coefficient with a constant coefficient of 1306.8 and exponent of 2.0883 which is against size and time. Results show that findings are in considerably high agreement with the experimental data.Keywords: Diffusivity, Mass transfer, Lemon, Drying.. . .