Effects Of Operating Parameters Research Articles

Effects of Dry Granulation Operating Parameters on Forming Quality

To address the issues of the existing dry granulation process, which mostly relies on manual adjustments based on empirical experience and lacks the analysis of theoretical data, a simplified model of tablet pressing based on a modified Drucker–Prager Cap (DPC) material constitutive model was proposed to simulate and analyze the forming process of tablets, and study the impacts of the feeding speed, roller speed, friction coefficient and roller clearance on the density distribution of the pressed tablets via ABAQUS. The results show that the roller speed significantly impacts the density of tablets, and a lower roller speed and a higher friction coefficient are beneficial to the formation of tablets. As the roller clearance decreases, the average density at the clearance increases, and the unevenness of the lateral density distribution of the tablets increases, showing a distribution trend of larger density at the center and smaller density on both sides.

A review of electro-Fenton and ultrasound processes: towards a novel integrated technology for wastewater treatment.

Nowadays, the presence of persistent dissolved pollutants in water has received increasing attention due to their toxic effects on living organisms. Considering the limitations of conventional wastewater treatment processes for the degradation of these compounds, advanced oxidation processes such as electro-Fenton and sono-chemical process, as well as their combination, appear as potentially effective options for the treatment of wastewater contaminated with bio-recalcitrant pollutants. In view of the importance of the development of processes using real effluents, this review aims to provide a comprehensive perspective of sono-electro-Fenton-related processes applied for real wastewater treatment. In the first section, the fundamentals and effectiveness of both homogeneous and heterogeneous electro-Fenton approaches for the treatment of real wastewater are presented. While the second part of this work describes the fundamentals of ultrasound-based processes, the last section focuses on the coupling of the two methods for real wastewater treatment and on the effect of the main operational parameters of the process. On the basis of the information presented, it is suggested that sono-electro-Fenton processes substantially increase the efficiency of the treatment as well as the biodegradability of the treated wastewater. The combined effect results from mass transfer improvement, electrode cleaning and activation, water electrolysis, and the electro-Fenton-induced production of hydroxyl radicals. The information presented in this work is expected to be useful for closing the gap between laboratory-scale assays and the development of novel wastewater technologies.

Investigation of optimal operating conditions in dimethyl ether carbonylation to methyl acetate production process.

Ethanol production methods are expanding due to the importance of ethanol as a fuel or additive to fuels. One of these methods is converting methanol to ethanol in a three-step process. All of these steps need to deeply study and investigate to develop the process. In this research, the carbonylation of dimethyl ether to produce methyl acetate, which is the intermediate reaction of the three-step process of methanol to ethanol, has been simulated and optimized. The parameters of temperature, pressure, residence time, and feed ratio have been investigated as effective operational parameters of the process. It has been shown that the temperature and pressure of the process are more effective in the ranges of 220-280 °C and 30-50 bar, respectively. The simulation results showed a maximum point in dimethyl ether conversion in the feed ratio of 0.4-0.6, i.e., in temperature of 260 °C, residence time of 5 h, pressure of 45 bar, DME/CO/Ar = 30/67/3, and DME conversion about 22%. Also, it has been shown that increasing the residence time increases the effect of each of the above parameters. Optimization of the dimethyl ether carbonylation process has demonstrated that the combination of different ranges of the above parameters achieves the desired conversion, i.e., in pressure of 48.23 bar, temperature of 259.06 °C, residence time of 3.68 h, and dimethyl ether/feed of 0.461 vol%; conversion of dimethyl ether will be equal to 85.50%.

Effect of operational parameters on the performance of a kenaf harvester

Aim of study: To develop a kenaf harvesting technology, that will improve kenaf production efficiency. This study evaluated the effect of some operation parameters on the performance of a tractor-mounted kenaf (Hibiscus cannabinus L.) harvester. Area of study: The experiment was performed at the Teaching and Research Farm of the Obafemi Awolowo University, Ile Ife, Nigeria. Material and methods: The experiment was initiated after 10 weeks of planting kenaf on the experimental field. The experimental design was a 3 × 4 × 5 experiment evaluating the effect of kenaf maturity (average stem diameter at week after planting (WAP) 10, 12, 14 and 16), kenaf varieties (‘Cuba 108’, ‘Ifeken 400’ and ‘Ifeken Di 400’) and forward speed of the tractor (2, 3.5, 5, 6.5 and 7.7 km/h) on effective field capacity, field efficiency, and operational loses of the machine. Main results: The effective field capacity of the machine decreased with increase in plant maturity and increased with increase in forward speed of the machine. The optimal value of the effective field capacity was 2.13 ha/day, when harvesting ‘Ifeken 400’, at crop maturity of 10 WAP, and forward speed was 5 km/h. The field efficiency of the machine was found to decrease with increase in crop maturity and forward speed of the machine. The field efficiency of the machine was 97%, with ‘Ifeken 400’ crop maturity of 10 WAP and forward speed of 2 km/h. Research highlights: The crop maturity, kenaf variety and forward speed of tractor have effect on the effective field capacity, field efficiency and the operational loss of the tractor-mounted kenaf harvester

Synergistical reduction of PM and NO formation in preheating co-firing of coal and biomass

Preheating co-firing of coal and biomass was proposed for synergetic mitigation of pollutant source emissions. The effects of different operating parameters on particle matter (PM) and nitric oxide (NO) emissions were investigated, including excess air ratio (αp), temperature (Tp), residence time (tp) in the preheating zone and temperature (Tc) in the combusting zone. Coal and biomass particles were fed separately by two feeders, mixed uniformly in a mixing device and then inserted in a high-temperature drop-tube furnace. PM and NO emissions at the furnace outlet were measured by ELPI+ and the infrared gas analyzer. The results showed that as αp increased from 0 to 0.5, PM10 emission declined by 10.65% while NO emission went down first and then rose up with a turning point at αp = 0.3 of 247.93 mg/m3. When Tp increased from 1400 K to 1800 K, PM10 emission increased but NO emission decreased. The increase in the former was more than twice the decrease in the latter. More interestingly, the forming mechanism of ultrafine mode PM0.3 was dominated by “solid-vapor” process at low combusting temperature but transformed into “vapor-particle” process at high temperature. When Tc ascended from 1700 K to 1800K, the dominant “vapor-particle” process was inhibited, leading to a decrease of 13.5% in PM0.3 emission. PM0.3-2.5, PM2.5-10 and NO emissions were boosted by 64.99%, 36.40% and 78.20% respectively with Tc ascending from 1400 K to 1800 K. As tp rose from 0.1 to 0.5, the production of PM0.3 and NO decreased by 29.50% and 44.55% respectively, but that of PM0.3-2.5 and PM2.5-10 increased by 20.04% and 33.83% continuously. Under optimum parameters (Tp = 1300 K, αp = 0.3, Tc = 1400 K and tp = 0.5 s), PM10 and NO emissions could be reduced by 30.88% and 48.01%, respectively.

Electrochemical oxidation treatment of reverse osmosis concentrated landfill leachate: Effect of operation parameters and evolution of dissolved organic matter

Electrochemical oxidation (EO) is a viable option for the advanced treatment of reverse osmosis concentrated landfill leachate (ROCLL). This work characterized dissolved organic matter (DOM) in ROCLL with size exclusion chromatography (SEC) and then investigated the impact of operating parameters on the removal of DOM fractions with response surface methodology (RSM). The SEC chromatograms revealed that the DOM fractions in ROCLL comprised of biopolymers (BP, > 18 kDa), humic substances (HS, 0.45–18 kDa) and low molecular weight substances (LMWS, < 0.45 kDa). For the EO configuration with different anodes, the BDD film anode showed the highest removal efficiency for DOM in terms of COD, DOC, UVA254 and fluorescence indices, followed by Ti, graphite, Ti/RuO2-IrO2 and Ti/SnO2-Sb2O5 anodes. The RSM experiments suggested that pH was the most critical factor to enhance the removal of all DOM fractions, and acidification pretreatment could remove approximately 50% BP and 30% HS fractions due to the pH-induced precipitation. The DOC removal kinetics of DOM fractions could be described by pseudo-zero kinetic model with rates in the order of HS > LMWS > BP, which were controlled by charge transfer process. Differently, the elimination of chromophores and fluorophores followed pseudo-first kinetics, which was limited by mass transport process. Via nonnegativity matrix factorization (NMF) deconvolution of the SEC-OCD chromatograms, BP-C1, HS-C2 and LMWS-C1 subfractions required to be removed through further treatment after EO process. This work demonstrates the potential for SEC analysis coupled with mathematical approaches to give informative insights into the evolution of DOM and provide optimization strategies for the EO treatment of complex ROCLL.

Design and Experiment of a Biomimetic Duckbill-like Vibration Chain for Physical Weed Control during the Rice Tillering Stage.

The widespread use of chemical herbicides has jeopardized concerns about food safety and ecological consequences. To address these issues and reduce reliance on chemical herbicides, a physical weed control device was developed for the tillering stage in paddy fields. This device features a biomimetic duckbill-like vibration chain that effectively controls weed outbreaks. The chain penetrates the soft surface soil of the paddy field under gravity and rapidly stirs the soil through vibration, leading to the detachment of the weed roots anchored in the surface layer. Simultaneously, the device avoids mechanical damage to rice seedlings rooted in deeper soil. This study aimed to investigate the effects of chain structural parameters (the number of chain rows, vibration amplitude, and length of chains) and operational parameters (vibration frequency and working velocity) on weed control efficiency and rice seedling damage. Through a central composite regression field test, the optimal device structure and operational parameters were determined. The optimization results demonstrated that a vibration amplitude of 78.8 mm, a chain length of 93.47 cm, and 3.4 rows of chains, along with a vibration frequency and working velocity ranging from 0.5 to 1.25 m/s, achieved an optimal weeding effect. Under the optimal parameter combination, field test results demonstrated that approximately 80% of the weeds in the field were effectively cleared. This indicates that the design of the biomimetic duckbill-like vibration chain weeding device exhibits a relatively superior weeding performance, offering a practical solution for the management of weeds in rice fields.

Population balance modelling of an electrocoalescer

The mechanism of dehydration of a water-in-oil emulsion is complex and involves the growth of an emulsion of polydispersed water droplets in oil, under an electric field, and their gravitational settling and phase separation. In this work, a simple configuration is chosen to understand the mechanism of this complex process. A population balance-based model is developed to predict the performance of an electrocoalescer. The model explicitly accounts for the coalescence of water drops by the action of dipolar forces and gravity settling. A distributed parameter plug flow and a tank-in-series model are developed to account for the gravity settling. The dynamics of electrocoalescence are captured by analyzing the drop size distribution and mean diameter along with the height of the coalescer and time. A simplified model - considering that monodispersity prevails throughout the process is also developed, and the separation curves are compared with the polydispersed system. The effect of operational parameters, such as the strength of the electric field, water cut, viscosity of oil, the height of the coalescer, and polydispersity in the initial drop size distribution, is investigated. The main insight from this work is that there are essentially three stages of electrocoalescence, a slow initial incubation stage where droplets grow to around 1 mm in size without much settling, followed by a rapid settling of these droplets to set in the fast coalescence stage where most water is removed to result in a lean emulsion, followed by a slow simultaneous electrocoalescence and separation stage of this lean emulsion to result in a final separation. A scaled masterplot for the performance of an electrocoalescer, encompassing the effect of the process parameters is obtained. The model also suggests that electrocoalescence essentially leads to a polydisperse system and a population balance approach is critical to its analysis.

Fuelling the future: Unleashing energy and exergy efficiency from municipal green waste pyrolysis

This study aims to determine how different operating conditions for a fast pyrolysis process employing municipal green waste (MGW) in an auger reactor affect product yields, overall energy efficiency, and total exergy efficiency. In this study, a range of pyrolysis conditions, including temperatures from 400 to 600 °C (in 50 °C increments), holding times from 1 to 5 min (in 1-minute increments), and feedstock particle sizes from 2 to 10 mm (in 2-mm increments) were used. MGW and pyrolysis products were characterised using separate pieces of equipment and in accordance with applicable ASTM standards. The results demonstrate that a yield of 52.8% for bio-oil and a yield of 23.7% for syngas can be achieved at temperatures of 500 and 600 °C, respectively. At 400 °C, the biochar production was highest as 21.5%. Bio-oil and syngas yields improved with holding times, whereas biochar yields declined. At a feedstock particle size of 2 mm, the overall energy efficiency was at its maximum (72.9%), while the total exergy efficiency was also at its highest (68.4%). As feedstock particle size increased, overall energy efficiency and total exergy efficiency dropped. In conclusion, this study provides valuable insights into the effects of different operating parameters on the pyrolysis process using MGW, which can be used to optimize the process and increase its efficiency.

Best management practices for minimizing undesired effects of thermal remediation and soil washing on soil properties. A review.

The use of remediated soils as end-of-life materials raises some challenges including policy and regulation, permits and specifications, technological limitations, knowledge and information, costs, as well as quality and performance associated with using them. Therefore, a set of procedures must be followed to preserve the quality and fundamental properties of soil during a remediation process. This study presented a comprehensive review regarding the fundamental impacts of thermal desorption (TD) and soil washing (SW) on soil characteristics. The effects of main operating parameters of TD and SW on the physical, chemical, and biological properties of soil were systematically reviewed. In TD, temperature has a more remarkable effect on physic-chemical and biological characteristics of soil than heating time. Therefore, decrease in temperature within a suitable range prevents unreversible changes on soil properties. In SW, more attention should be paid to extraction process of contaminants from soil particles. Using the right dosage and type of chelating agents, surfactants, solvents, and other additives can help to avoid problems with recovery or treatment using conventional methods. In addition, this review introduced a framework for implementing sustainable remediation approaches based on a holistic approach to best management practices (BMPs), which, besides reducing the risks associated with different pollutants, might provide new horizons for decreasing the unfavourable impacts of TD and SW on soil.

Modeling and microstructural study of anode-supported solid oxide fuel cells: Experimental and thermodynamic analyses

Developing novel solid oxide fuel cells (SOFCs) with high stability running at low temperatures is an important objective in SOFC science. In the current paper, a comprehensive physics-based microstructure modeling using scanning electron microscope (SEM) image analysis was performed on several anode-support SOFCs operating at low temperatures with high stability. To bridge the gap in the literature regarding an accurate and realistic modeling, a new model was developed based on the variable fuel and air utilization factors and updated microstructure values (e.g., tortuosity, porosity, pore size, grain size). The model accuracy was verified by a thorough point-to-point validation for eight different cells with the configuration of Ni-YSZ (anode), YSZ (electrolyte), and GDC/PNO (cathode). Different temperatures, hydrogen, and air mass flow rates were used, for which an average error of less than 3% in the I-V curves was achieved. The microstructure of the cells, including cathode thickness (15–26 μm), anode-support thickness (350–460 μm), porosity (39 and 43%), grain size (1.1–1.4 μm), and pore radius (0.9–1.1 μm) were varied. Moreover, the effects of the critical operational and design parameters on the overpotential losses and cell performance were studied. The results show that a hydrogen flow rate of 43 sccm was ideal when the cell operated at 0.9 A/cm2 and 700 °C. Moreover, an average anode-support pore radius of 1.75 μm resulted in the best cell performance. It was also concluded that the electrolyte thickness has a higher effect on the cell performance compared to the cathode thickness.

Electrostatic precipitation (ESP) index driven bio-aerosol collection for a high biological viability sampling

In this work, a two-stage electrostatic precipitator as the integration of a pre-charger and an electrostatic collector is proposed for airborne bio-aerosol sampling, where a pre-charger was applied for collection efficiencies enhancement and the following parallel-plate collector captured bio-aerosols with high biological viabilities. And the effects of operation parameters, including applied voltages, flow rates and collection area, on both the physical collection efficiency and biological viability are investigated. Specifically, the electric field strength of 4.3 kV/cm keeps the best balance between sampling efficiency and microorganism survival. For general designs and applications of present two-stage sampler, the modified ESP index and Pre-charger index are defined based on the charging characteristics of two typical bio-aerosols as Escherichia Coli and Candida albicans for predicting physical collection efficiency, biological viability and their ratio. A porotype with 2 × 1012 s V2 m−3 and 1.5 × 1014 s V2 m−5 for ESP and Pre-charging Index, respectively, obtains collection performance 3–5 times higher than conventional AGI-30 sampler during an on-site sampling, proving its feasibility for bio-aerosol collection.

Study on Effects of Operating Parameters on a Water-Cooled Loop Thermosyphon System under Partial Server Utilization

During the operation of a data center, servers are gradually installed in racks, causing most racks to work under a low heating load for a long time and affecting the cooling efficiency of the loop thermosyphon system (LTS). Thus, the effects of operating parameters on the thermal performance should be investigated. In this study, a water-cooled LTS was experimentally investigated under different airflow rates and heating loads. The results show that the additional liquid refrigerant reduced the heat transfer performance and aggravated a drop in cooling capacity when the airflow rate and heating load were decreased. To further reveal the effects of the operating parameters on the thermal performance and cooling efficiency, a steady-state distributed-parameter model was developed and validated based on the experimental data. The results show that the excessive cooling capacity was reduced by decreasing the airflow rate according to the upper limit of the server exhaust air temperature under partial server utilization. The excessive cooling capacity was reduced by 14.5–52.1% under 5–56.5% server utilization. To further reduce the excessive cooling capacity while ensuring thermal security, the water side operating parameters (including the supply chilled water temperature and water flow rate) were adjusted according to the upper limit of the rack’s average outlet air temperature, which reduced the excessive cooling capacity by more than 23.8% under partial server utilization.

Thermally activated persulfate oxidation of Basic Fuchsin dye: Effect of different operating parameters, kinetic, and thermodynamic study

AbstractThe present paper aims to investigate the efficiency of thermal activation persulfate in eliminating the organic dye “Basic Fuchsin” (BF). In addition, the study attempts to elucidate the effect of different operating parameters, such as persulfate dosage (0.44–4.4 mM), the initial solution pH of (3–10), and temperature (25–50°C), on the process. The effects of various anions and water matrices on BF discoloration were investigated. Thus, the findings revealed that 94.15% of BF can be eliminated using persulfate at a concentration of 4.4 mM and a temperature equal to 50°C. It occurs under the following operating conditions: oxidation time of 60 min, initial pH equal to 6, the pollutant concentration of 10 ppm, and stirring speed equal to 300 rpm. Furthermore, the kinetic study indicated that the degradation of the BF dye using PS followed a first‐order pattern with rate constants varying within a range of 15.3 × 10−3–43.2 × 10−3 min−1. Based on the Arrhenius equation, the activation energy of the studied process was determined to be 29 kJ mol−1, suggesting that a moderate activation energy is required for BF discoloration. The results of the thermodynamic study confirm that the oxidation process is non‐spontaneous and endothermic. Coexisting inorganic anions delayed BF discoloration to varying degrees, and the inhibitory action followed the following order: carbonate &gt; chloride &gt; sulfate &gt; nitrate. Organic pollutants oxidation by the thermal activation of the persulfate is a simple and effective method for the depollution of waste textile water.

Usage of MnFe2O4-rGO Nanocomposite as efficient Fenton catalyst for Tetracycline removal by heterogeneous sono Fenton process: Characterizations, catalytic performance assessment, and mechanism

In this study, monodisperse MnFe2O4/rGO nanoparticles was prepared and used as Fenton catalyst for Tetracycline (TC) degradation combining with ultrasonic process. The physicochemical properties of the resulted NPs were detected transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy techniques. The effect of operational parameters containing amount of catalyst, H2O2 concentration, initial TC concentration, initial pH of solution, ultrasonic power, and process time on the TC removal efficiency during heterogeneous sono-Fenton process was studied. The best sonocatalytic efficiency of 92.85% was attained by using 0.3 g/L MnFe2O4/rGO nanocatalyst, 10 mg/L TC, 12 mM H2O2, 450 W ultrasonic power, and at pH = 3 after 120 min. By using organic and inorganic scavengers, the primary active species was determined for TC removal during heterogeneous sono-Fenton oxidation.The results showed that ROS species were effective in TC removal in the order h+ > •OH > O2•−. Moreover, MnFe2O4/rGO nanocomposite were reusable up to the five consecutive cycles without any notable loss in activity.

Evaluation of synergistic adsorption approach for terbinafine removal by cotton shell powder immobilized zerovalent copper: Adsorption kinetics and DFT simulation

Cotton shell powder (CS), nano zerovalent copper (nZVC) and cotton shell powder immobilized zerovalent copper (ZVC@CS) were evaluated for their adsorption efficiencies towards terbinafine hydrochloride (TBH), an antifungal drug. The nZVC and ZVC@CS synthesized via one pot redox precipitation method were characterized by FTIR, XRD, BET, FESEM and TGA analysis. The TGA and AAS analysis confirmed the loading of nearly 10% of nZVC on cotton shell powder in ZVC@CS. The effect of operational parameters (pH, adsorbent dose, initial drug concentration, time, etc.) determining the extent of terbinafine hydrochloride adsorption on ZVC@CS were investigated to ascertain the optimal experimental conditions to achieve maximum adsorption efficiencies. To investigate the adsorption behavior of TBH on ZVC@CS, the experimental data were fitted for five different adsorption models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson and Hill isotherms. The TBH adsorption data was best fit with Hill isotherm model indicating cooperative sorption of TBH molecules on ZVC@CS surface. Among the five kinetic equations namely the pseudo-first-order (PFO), the pseudo-second-order (PSO), Elovich model, the intraparticle diffusion model, and Boyd kinetic model used to estimate the adsorption mechanism, the PFO kinetic model give best fit with a good correlation for the physisorption of TBH on ZVC@CS composite. The mechanism of the adsorption process was observed to be complex, consisting of both surface adsorption and pore diffusion. However, the Boyd plot confirms external mass transport as the rate limiting step for the adsorption of TBH on ZVC@CS. The synergistic adsorption of TBH on ZVC@CS was hypothesized, and the idea was supported by structure optimization results from DFT studies. The ZVC@CS exhibits equilibrium TBH adsorption efficiency (qmax) of 285.3 mg.g−1, significantly higher than adsorbents used in literature for the TBH removal.It is suggested that ZVC@CS may serve as sustainable adsorbents for the removal of cationic contaminants from acidic medium.

Bond properties and anisotropy performance of 3D-printed construction and demolition waste-based geopolymers: Effect of operational- and material-oriented parameters

This study investigated the bond performance of printed construction and demolition wastes (CDW)-based geopolymer, providing utilization of CDW in green materials through high tech-manufacturing methodologies. Considering the requirements of three-dimensional-additive manufacturing (3D-AM), the effects of operational and material-oriented parameters on mechanical performance were examined by conducting compressive strength, triplet shear, direct tensile, and diagonal tension tests. Anisotropy performance (perpendicular, lateral, and parallel), printing time intervals (0, 15, 30, 60-min.) between two consecutive layers, material aging time (0, 30, 60, 120-min.) of CDW-based materials, manufacturing methodologies (cast, horizontal- and vertical-printed) were evaluated on the printed specimen. The study showed that the tests conducted on masonry structures could be used on the 3D-printed structure as well. An anisotropic behavior in the compressive strength results was obtained by observing a decreasing trend in results from perpendicular to parallel and, parallel to lateral loading directions. Increasing printing time interval had a negative influence on the compressive strength of CDW-based geopolymers and anisotropy performance was mitigated in a 60-min printing time interval. Although bond strength decreased with raised printing time intervals, similar bond strength values were recorded for 30-min and 60-min printing time intervals. Similarly, increased material aging time caused decrement in bond strength, yet comparable bond strength was obtained for specimen printed with 60-min and 120-min aged mixture. According to the results, printing time intervals showed more prominent effects on bond strength compared to the material aging time. The test results indicate that vertical-printed specimens demonstrated similar mechanical performance with cast specimens, whereas horizontal-printed specimens exhibited slightly weaker performance compared to those.

Thermal-hydraulic characterization of R513A during flow boiling inside a 6.0 mm horizontal tube, comparison with R134a and development of a new correlation

This paper presents two-phase heat transfer coefficient and pressure drop data of refrigerant R513A, a new azeotropic mixture conceived as possible alternative to R134a for medium temperature small-size refrigeration systems. All the experiments were performed in a commercial horizontal stainless-steel tube having an internal diameter of 6.0 mm and an outer diameter of 8.0 mm. The channel heating was obtained through DC current and Joule effect. The effect of the main operating parameters in terms of mass flux (from 150 to 500 kg/m2s), heat flux (from 5.0 to 40 kW/m2), saturation temperature (from 30 to 50 °C) and vapor quality (from the onset of boiling up to the dry-out occurrence) was analyzed and discussed for the heat transfer coefficient values, finding that both convective and nucleate boiling were significant contributions. The same ranges of mass flux and saturation temperature were also applied to frictional pressure gradient trends with vapor quality, taken in adiabatic conditions. The thermo-hydraulic performances were then compared with those of R134a, obtaining lower heat transfer coefficients and very similar pressure gradients. Finally, the collected experiments were assessed with values predicted from the most quoted correlations available in literature. A new composite method for nucleate-dominant or convective-dominant mechanisms was proposed for the evaluation of the heat transfer coefficient, with a mean absolute error of 25.3%, whereas the frictional pressure gradient values were well predicted with the Friedel correlation, that provides a mean absolute error of 13.8%.

The Effect of Operating Parameters on Total Cross-membrane Flux in a PVDF Flat Sheet Membrane

Membrane distillation (MD) is an emerging thermal membrane technology that involves water vapor driven by a vapor pressure gradient over a hydrophobic membrane. MD faces several challenges, one of which is the flux of water vapor. The total cross-membrane flux in membrane distillation was investigated in this paper using the co-current PVDF flat sheet for direct contact. membrane distillation applications. The goal of this research is to improve total cross-membrane flux. The effect of various operational parameters is studied, including feed inlet temperature (333.15–358.15 K), feed flow rate (1–2.5 kg/s), permeate inlet temperature (288.15–313.15 K), and feed inlet NaCl concentration (0.035 to 0.485 kg/kg). To acquire a good value of total cross-membrane flux, their interactions with the total cross-membrane flux are studied in this work. The obtained results were computed during MATLAB-Simulations under several scenarios adopting the Trial-&amp;-Error approach. This last inputs various parameters' values and thus draws the required curves to be discussed and analyzed. The results indicated that the PVDF flat sheet membranes provide a significantly higher total cross-membrane flux at higher feed input temperatures, producing a 73.2075 kg/(m2 h) at a feed inlet temperature of 358.15 K, a permeate inlet temperature of 293.15 K, and a flow rate of 2.5 kg/s, with a feed inlet NaCl concentration of 0.035 kg/kg. Feed inlet temperature significantly affected the total flux through the membrane; however, flow rate, permeate inlet temperature, and feed inlet NaCl concentration had a less significant effect.

Comparison of CO2 absorption in DETA solution and [bmim]-[PF6] using thermodynamic and process modelling

Non-conventional amines are being research around the world to overcome the problems associated with traditional and conventional amines such as monoethanolamine (MEA) and methyldiethanolamine (MDEA). Having appropriate and specific process and thermodynamic models for these amines is vital to recognize their applicability and performance for CO2 absorption. However, studies on process modelling of these types of amines are very limited. In this study, the rate-based modelling was utilized for a packed column to obtain profiles of operating variables for CO2 absorption by Diethylenetriamine (DETA) solution. Deshmukh-Mather (D-M) method as thermodynamic modelling was incorporated in the rate-based model. The process model was validated using experimental data from the literature. Additionally, a sensitivity analysis of mass transfer correlations was performed on the temperature and concentration profiles. The effect of different operational parameters on the CO2 removal efficiency was studied, and the CO2 absorption efficiency of DETA solution was compared with that of an ionic solvent, 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim]- [PF6]). The effect of different parameters on the CO2 removal efficiency highlights the need to find optimum operating parameters for absorber column to achieve the maximum absorption efficiency. Although the absorption efficiency of CO2 by ionic solvent was higher than that of DETA solution under the same operational conditions, the advantages, and the disadvantages of each solvent in CO2 capture processes should be considered without compromising the solvent performance.