Production data analysis techniques have been widely used for estimating reservoir properties such as gas in place and average pressure. Knowledge of this information is crucial for proper reservoir ...management. The present study discusses the roadmap, challenges and uncertainties for analyzing production data in an Iranian gas-condensate offshore field. This work is an integrated study involving the quality check of production data, platform process simulation, orifice simulation, modeling choke performance, well modeling, and Rate Transient Analysis (RTA). The study is an inverse analysis which starts from production platform and continues down to the reservoir. To perform data analysis, we propose five general steps which are: Data gathering/extraction/quality check, well rate determination, well bottom hole pressure estimation, layer rate allocation, and reservoir property estimation. In this study, these steps are discussed elaborately. Furthermore, challenges of each step are presented and discussed. In addition, the required input and also missing data for each step is mentioned. Also, to cope with lack and/or uncertainties of data, feasible solutions are proposed for the current field situation as well as future developments. This paper can help petroleum engineers to know where to start and how to proceed to get to the final step of the analysis, i.e. estimating field gas in place. It also provides insights into challenges and uncertainties of the production analysis in gas-condensate
•Metal oxide nanofluids were prepared and characterized by DLS analysis for CO2 separation.•Polypropylene hollow fiber membrane contactor was used for CO2 elimination from N2.•Al2O3, TiO2 & SiO2 ...nanoparticles with 0.05, 0.1 and 0.2 (wt% in H2O) were used.•Removal efficiency and mass transfer flux enhancement were reported.•New correlation was developed for Sh number based on experimental results.
The elimination of carbon dioxide (CO2) using water-based nanofluids (NFs) in a hollow fiber membrane contactor (HFMC) using polypropylene (PP) membrane was experimented. Gas flows in the shell, while NF flows in the fibers. Metal oxide nanoparticles (NPs) such as aluminum oxide (Al2O3), titanium dioxide (TiO2) and silica (SiO2) in the concentrations of 0.05, 0.1 and 0.2 wt % were used in the experiments. Some factors such as gas flow rates, NPs type, NF temperature, NP concentration, as well as the effect of particle size on the separation were investigated. The results clearly show that the highest flux of CO2 occurred for 0.2 wt % concentration of Al2O3 NFs. Mass transfer flux enhancement (MTFE) was defined as the relative mass transfer flux (MTF) of CO2 in the NFs with respect to the MTF of CO2 in the de-ionized water as the base fluid. MTFE changed from 1.29 to 2.25 for the Al2O3 NFs. Among all the results, the best result was obtained for Al2O3 (40 nm) at 1.6 Lit/min liquid flow rate, 25 °C liquid temperature, 5 Lit/min gas flow rate and 40% inlet CO2 concentration which is 98.9% CO2 removal. Finally, a new correlation was developed for the Sherwood (Sh) number for the CO2 mass transfer in the NFs flowing in the fibers. Sh number was developed based on the NFs Reynolds (Re) number, NPs Reynolds (Renp) number, Schmidt (Sc) number, and NPs volume fraction with an average relative error percent (REP) of 1.6% and R2 of 0.99.
•Green synthesized AuNps were used in the preparation of an electrochemical sensor.•DPV was used for evaluating the phenolic, antioxidant content, and radical scavenging activity.•Human interleukin-2 ...gene probe was used for preparation of biosensor (DNA/AuNPs/SPE).•The designed sensor was used to investigate the effect of algae extract on inhibiting DNA damage.•The anticancer activity of the alga extract on some cancer cells were examined using the MTT assay.
In this paper, the electrochemical method was used as a rapid and sensitive method to measure the antioxidant activity of Acanthophora red macro-algae (collected from the Persian Gulf coast of Bushehr-Iran). The algae extract was obtained by a combination of maceration and microwave methods, and then the important volatile and bioactive compounds were identified by GC-Mass analysis. To prepare the sensor and improve the electrochemical signal, gold nanoparticles synthesized by the green method were used to modify the electrode surface. Differential pulse voltammetry method (DPV) was used to investigate the inhibitory effect of the extract on ABTS and DPPH radicals.
To investigate the ability of the Acanthophora algae extract to prevent DNA damage induced by Fenton reaction, an electrochemical biosensor was designed based on the immobilization of human interleukin-2 (IL-2) gene probe on the surface of gold nanoparticle-modified carbon screen-printed electrode. Then, the protective effect of the algae extract was investigated by electrochemical impedance spectroscopy. Finally, the toxicity effect of Acanthophora algae extract on the HT-29, SKOV3, MCF-7, and SKMES-1 cancer cell lines was evaluated by MTT assay.
•Condensate vaporization tests are conducted to investigate mass transfer aspects.•New models determine mass transfer coefficient for condensate vaporization cases.•Both convection and dispersion ...mechanisms are incorporated in the models.•There is good agreement between experimental data and modeling results.•Gas rate and grain size have the highest and lowest importance, respectively.
Condensate vaporization in porous media occurs in several processes such as remediation, absorption/adsorption in packed beds, and gas recovery. Most of modeling/simulation investigations on condensate recovery processes assume local equilibrium to model mass transfer rate of components involved in the inter-phase mass transfer phenomenon. This assumption does not seem realistic, since high fluid velocity and limited contact area may result in an appreciable deviation from the equilibrium condition. In this study, vaporization of liquid condensate components into the flowing gas stream is explored through experimental and modeling approaches. We take into account the non-equilibrium inter-phase mass transfer. A key parameter in the non-equilibrium mass transfer is the mass transfer coefficient. Lack of adequate laboratory data concerning the vaporization of condensate components into the gas phase motivated us to conduct a systematic experimental work. Taguchi design of experiment (DOE) is implemented to optimize the experiments in terms of number of runs and process conditions. To accurately estimate the mass transfer coefficient, the diffusion/dispersion and convection mass transfer mechanisms are incorporated in the modeling of condensate vaporization in porous systems for the first time. The statistical tests are also employed to assess the relative importance of diffusion/dispersion and convection mechanisms in the condensate vaporization process. The optimum levels of design factors are found using signal to noise ratio (SNR) plots generated through using the Taguchi DOE. According to the statistical analysis, the diffusion term has no considerable impact on the magnitude of the mass transfer coefficient. The experimental results also reveal that the highest relative significance/contribution (about 36%) belongs to the gas flow rate. The second place is given to the liquid type with 28.83% contribution. The gas type and mean grain size hold the third and fourth ranks with 11.8% and 10.61% contributions, respectively. The experimental results confirm non-equilibrium mass transfer over condensate vaporization event, particularly at high-velocity conditions. Combining the theoretical concepts and experimental data, new empirical mass transfer correlations are suggested in this study that can be incorporated in commercial software packages for obtaining the mass transfer coefficient with a high precision.
The solar-driven photocatalytic process, as a clean and efficient advanced oxidation process (AOP), is widely operated in wastewater treatment applications. In the present work, a solar nano ...photocatalytic reactor is designed, manufactured, and tested under different operating conditions. The irradiation-dependence reaction kinetics is studied in a batch operation process. A comprehensive computational fluid dynamics (CFD) model taking into account realistic solar flux distribution is developed and validated using experimental data. Finally, the reactor scaling-up analysis for higher treatment capacities is performed with the aim of the design of industrial-scale solar photocatalytic reactors. The research results indicate that when the initial dye concentration is increased from 5 to 175 mg/L, the period required to achieve 95% pollutant removal in 20 L solution and 10 mg/L photocatalyst concentration boosts up to 2.2 times. When the photocatalyst concentration in the solution is increased from 5 to 20 mg/L, the time required to achieve 95% total removal is reduced to 35.7%. For the photocatalyst concentration of 75 mg/L compared to 20 mg/L, the time required for 95% degradation increases up to 16.7%. To treat 90% of the total pollutant in a 50 mg/L dye solution with an initial volume of 5 m3 and using 20 mg/L photocatalyst concentration under 11 h operation with an average solar irradiation intensity of 750.46 W/m2, a solar reactor with a surface area of 50.45 m2 is required, while for 10 m3 wastewater sample and the same conditions and 95% pollutant removal, the collector area is obtained to be 121.36 m2. A horizontal solar reactor compared to its optimal tilt angle can reduce the treatment capacity up to 55%.
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•A solar-driven nano photocatalytic reactor for wastewater treatment was investigated.•The irradiation-dependent kinetics and CFD modelling of the reactor were performed.•A strategy was suggested to upscale the system and determine the reactor size for increased capacities.•Initial dye concentration and photocatalyst concentration affect treatment efficiency.•Collector tilt angle optimization is crucial for the highest performance.
In this work, a global kinetic model of hydrothermal liquefaction (HTL) is proposed for Aurantiochytrium sp., C. protothecoides, Scenedesmus sp., Chlorella vulgaris, and Tetraselmis sp. algae. ...Proteins, lipids, and carbohydrates were first decomposed to the aqueous phase and biocrude, followed by further decomposition to the gas phase. MATLAB optimization function was used to optimize the kinetic parameters of different algae. Furthermore, economic analysis was evaluated by using global kinetic modeling to estimate HTL product yields in Aspen Plus. The results showed that the calculated optimum values of activation energies were 31–50, 32–52, and 46–90 kJ/mol for the conversion of proteins, lipids, and carbohydrates to biocrude. Also, the global kinetic model had a great predictive ability with a reduced chi-square of 0.717 and
R
-squared of 0.987. Moreover, the application of the global kinetic model for different biomass such as Chlorella vulgaris, sewage sludge, green waste, food waste, grease residue, and their 50:50 mixtures with Chlorella was evaluated. The yields of Chlorella vulgaris, green waste, food waste, and their mixture with Chlorella could be predicted by the kinetic parameters of Scenedesmus sp., while kinetic parameters of Aurantiochytrium sp. were more appropriate for yield predicting of grease residue. Moreover, HTL techno-economic analysis of Aurantiochytrium sp. showed that the various ranges of the minimum fuel selling price (MFSP) were estimated to be $2.11 to $7.52/GGE by the effect of biomass price.
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In this study, a transmission line model is applied to the electrochemical impedance spectroscopy (EIS) data of the fabricated dye-sensitized solar cells (DSSCs) to evaluate the charge transfer ...mechanism through the cells. Natural dye from black plum (Syzygium cumini) fruit was used as a cell sensitizer (SC-DSSC) and compared its photovoltaic and electron transport capabilities to those of a cell using a synthetic sensitizer (N719-DSSC). TiO2/ZnO electrospun composite nanofibers were used as the semiconductor layer of the photoanode to enhance electron transfer. The EIS analysis revealed the role of electron resistances through shant, interfaces, and electrolyte solution by measuring the electron transfer kinetic parameters of each element. Based on the results, the SC-DSSC and N719-DSSC are appropriate photovoltaic cells because their ratios of effective electron diffusion length to photoanode thickness are 12.5 and 2.8, respectively. The EIS analysis showed that the electrospun composite nanofiber coated on the photoanode reduces the semiconductor layer's electrical resistance to the cell's total resistance. The extracted natural dye also boosted electron lifetime to 3.68 ms and diffusion coefficient to 54.3×10−6 m2/s while minimizing back-electron recombination at the semiconductor-electrolyte interface. Moreover, the semiconductor-electrolyte interface resistance is over 85% of the overall resistance for both DSSCs and controls electron transport through the cells, which is due to the dye-semiconductor binding intensity. Based on the photovoltaic data, the SC-DSSC cell efficiency was lower than N719-DSSC which is attributed to its higher electron transfer rate-controlling element. Thus, enhancing dye-semiconductor interactions will decrease the rate-controlling impedance and enhance cell performance.
In this study, wound dressings consisting of dexpanthenol (Dex)-loaded electrospun nanofibers were fabricated using polyvinyl alcohol (PVA)/sodium alginate (SA), and chitosan as the core and the ...shell, respectively. Considering the remarkable properties of chitosan, it was used as a shell against drug release and to improve the thermal stability, and tensile strength of the scaffold. By comparing the thermogravimetric, and tensile strength results of nanofibers with and without shell, it was revealed that the presence of chitosan in the shell side could improve the thermal stability and increased the tensile strength by about three times. The isotherm models of dexpanthenol release from the PVA/SA/Dex-CS scaffold was best described by the Langmuir model. Besides, Fourier transform infrared, scanning electron microscopy, and X-ray diffraction techniques were performed to characterize nanofibers. Furthermore, an in vivo investigation of a wound dressing with dexpanthenol showed better healing compared to the wound dressings without dexpanthenol.
•The uniform fibers were made using natural alginate polymers.•Chitosan shells increased the thermal stability of the wound dressing.•The drug release was performed in a controlled manner and based on the Langmuir isotherm model.•Wound healing was accelerated by drug-loaded nanofibers.
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•The conditions and compositions of flare gas in a giant gas refinery are measured.•Two feed compositions were simulated in LPG unit and evaluated by operating data.•Three methods for ...FGR were investigated including two novel methods.•More than 80% of flare gases, 205ton/day CO2—equivalent recovered by novel methods.
Flare gas recovery (FGR) is known as an option to reduce greenhouse gases (GHG) from oil and gas refineries. The major concerns about environmental impacts of GHG emission lead refineries to deploy different FGR methods, most of which requiring new equipment and high cost of design and construction. In this paper, feasibility of three methods for FGR is evaluated in a giant gas refinery in Iran. The first two methods considered liquefaction and LPG production by implementing flare gases as feed for existing LPG unit. Different parameters were studied in feed liquefaction and LPG production. The third studied option is using a three-stage compression unit to compress the flare gases. Finally, an economic evaluation was performed to find the most profitable method. Based on simulation results, the 0.75-barg pressure of flash drum leads to maximum LPG production. For FGR, the 1-barg pressure of flash drum recovered the most CO2-equivalent from releasing into the atmosphere, which is more than 205ton/day. The economic evaluation shows that rate of return (ROR) for liquefaction unit and LPG production unit are more than 200% for different scenarios and are higher than compression.
