Influence Of Flow Rate Research Articles

Study of ship-based carbon capture optimization considering multiple evaluation factors and main engine loads

Ship-Based Carbon Capture (SBCC) technology presents a promising approach to reduce greenhouse gas emissions in the marine transportation. Solvent-based carbon capture has emerged as a leading technology for SBCC, primarily due to its low retrofit costs and effectiveness in treating flue gas with low carbon content. However, challenges remain in optimizing system operation efficiency under the variable conditions of ship main engine loads and in understanding the mechanisms by which process parameters influence key evaluation factors. Consequently, this study established a pilot-scale experimental platform for solvent-based SBCC and developed a carbon capture model based on it. The influence of process parameters, such as main engine exhaust flow rate and liquid/gas ratio (L/G), on the evaluation factors was thoroughly explored. With the utilization of Shapley Additive Explanations (SHAP) analysis to quantify the influence of process parameters on the evaluation factors, a multi-objective optimization equation is proposed. The combination of machine learning and optimization algorithms offers an efficient approach for determining the optimal process of the SBCC system under different main engine loads. The research results show that the main engine exhaust flow rate is the most important process parameter affecting the carbon capture rate (CR), with an influence ratio as high as 64.33%. As the main engine exhaust flow rate increases, the maximum CR decreases from 97.84% to 61.13%. Although the extreme value of the regeneration energy consumption (REC) also decreases from 6.66 to 4.42 GJ/t CO2, the solvent flow rate's influence on REC is also significant, with influence ratios of 38.49% and 35.53%, respectively. A data-driven approach examined the optimal operating conditions at eight main engine loads, achieving a carbon capture rate prediction error of only 1.42% and a maximum REC error of only 0.55 GJ/t CO2. This study provides essential guidance for assessing the suitability of SBCC systems.

Regeneration of coked catalysts via ozonation: Experimental study of diffusion–reaction mechanisms at pellet and reactor scales

This work focuses on regeneration of coked catalysts using ozonation as an alternative process to typical coke combustion with oxygen. Different samples of coked ZSM-5 zeolites obtained during catalytic pyrolysis of polyethylene at 450 °C were exposed to an ozone enriched stream in a fixed-bed reactor. The influence of main operating parameters (time of exposure, temperature, O3 inlet concentration and gas volumetric flowrate) were studied by evaluating coke removal efficiency and by observing regeneration behavior both at pellet and reactor scales. These experimental results led to a better insight of the diffusion–reaction phenomena occurring during the process. Diffusion limitations were illustrated thanks to an innovative method, the analytical acquisition of carbon radial profiles on catalyst pellets, while the apprehension and quantification of competing reactivity (thermal, catalytic and oxidation) gave a better understanding of the ozonation process. Time of exposure and temperature were found to significantly affect carbon removal efficiency, while inlet ozone concentration and flowrate influence were respectively moderate and null in the investigated range. Similarly to combustion, coke ozonation is driven by a balance between diffusion and reactivity, leading to the appearance of a mix of known regeneration regimes depending on the operating conditions: homogeneous and shrinking-core.

Experimental and simulation research on heat extraction characteristics from a pilot-scale reverse flow reactor for low-grade energy

This work presents heat extraction characteristics in a pilot-scale thermal flow reversal reactor dedicated to the mitigation of ventilation air methane escaping from coal mining and the recovery of residual heat. The heat extraction mode arranged on both sides of the central zone was applied. The influence of flowrate, concentration and reversing time on comprehensive heat transfer performance were investigated through experiments. The temperature evolutions and the quantitative relationship between temperature evolutions and heat extraction were predicted through simulations. The experimental results show that low flowrate is susceptible to establishing rapidly initial temperature field. The heat recovery rate and generated superheated steam increase with concentration and varies parabolically with switch time. The optimum heat extraction is that heat recovered is slightly greater than or close to the stored heat. Therefore, the heat extraction research involved in this paper will provide a reference for other low-grade waste fuels in industrial applications.

Membrane fouling remediation and modeling in phosphorous removal using electromagnetic field (EMF)-assisted nanofiltration (NF): In situ synchrotron imaging, experimental and statistical studies

Phosphorous loading in the natural waters is a current issue that is caused by the discharge of industrial water, agriculture run off, and municipal releases. Membrane technology is an emerging method to target the removal of phosphorous from wastewater and has several advantages over the traditional methods. However, the main challenge of membrane technology is membrane fouling. The main goal of this study was to optimize nanofiltration process of phosphates using electromagnetic field (EMF) as an eco-friendly membrane fouling remediation technique. To obtain this, several test runs were performed on a commercial membrane Dow NF270 for nanofiltration of synthesized water with various concentrations of phosphate. The application of EMF altered the particle size of phosphate that resulted in a significant decrease in membrane fouling while obtaining maximum flux. In situ synchrotron-based micro–Computed Tomography imaging (SR-μCT) available at the Canadian Light Source (CLS) was conducted to assess membrane fouling with and without EMF influence across layer by layer across membrane thickness. Synchrotron X-ray analysis revealed the decrease in internal membrane pores fouling, caused by increase of phosphate particles size when using EMF. In addition, SEM images of membrane showed reduced fouling. The influence of flowrate, pressure, pH, and phosphate concentration was observed on permeate volume, permeate flux, and membrane fouling. It was determined that flowrate, transmembrane pressure, and pH had were directly proportional to the permeate volume, while the phosphate concentration was indirectly proportional. Mathematical models were developed to obtain the optimized operating conditions and to determine which factor influenced water flux and membrane fouling the most. The transmembrane pressure was the most significant factor for water permeate flux, while the combination of the influence of pH and feed flowrate had also a positive effect. On the other hand, the feed concentration was the most significant for membrane fouling, according to mathematical model. The optimized conditions with the highest desirability had the concentration of phosphate at 0.368 mg/L, pressure at 97.8 psi, 6.98 pH, and flowrate of 5.13 L/min. Under these conditions, maximum flux of 7.43 mL/cm2/min and minimum fouling of 0.046 mg/cm2 was achieved.

Influence of flowrate and composition of the alkanes dehydrogenation process feedstock on by-products concentration in the linear alkylbenzene sulfonic acid manufacturing technology

Synthesis of surfactants based on linear alkylbenzenesulfonates is a complex multi-stage process that includes the following stages: alkanes dehydrogenation on Pt-containing catalyst, dienes hydrogenation on Ni-containing catalyst, HF-catalyzed alkylation of benzene with alkenes, and sulfonation of linear alkylbenzenes (LAB) with sulfur trioxide in a film reactor yielding alkylbenzene sulfonic acid (ABSA). When developing mathematical models of multi-stage processes it is necessary to consider the contingency of the apparatuses in the chemical-technological system. The design of the sulfonation reactor, as well as the feedstock composition and the dehydrogenation unit performance, i.e., the LAB flowrate to sulforator, significantly affects the ABSA synthesis efficiency. The studies were performed using the unsteady mathematical models of conjugated dehydrogenation and sulfonation processes. As a result, we determined the optimal design of the sulfonation reactor with number of tubes n = 40 and diameter d = 43 mm. We also outlined the preferred method for increasing the ABSA yield by switching to a double-reactor alkane dehydrogenation scheme with a flowrate of 100 m3/h for two dehydrogenation reactors. This increases yield of alkenes and LAB by 71 %wt.

The influence of flowrate and gas density on positive airway pressure for high flow nasal cannula applied to infant airway replicas

High flow nasal cannula (HFNC) therapy has been previously shown to produce positive upper airway pressures in adult and child patients. This work aimed to evaluate and quantify the effects of HFNC flowrate and gas type on airway pressures measured in vitro in infant airway replicas.Ten realistic infant airway replicas, extending from nares to trachea, were connected in turn to a lung simulator and were supplied gas flows through HFNC. Air and heliox were each provided at two weight-indexed flowrates, 1 l/min/kg and 2 l/min/kg. Pressure and lung volume were continuously measured during simulated breathing.For constant simulated patient effort, no statistically significant change in tidal volume was measured between baseline and lower or higher HFNC flowrates, nor was there any significant difference in tidal volume between air and heliox. Tracheal pressure increased with increasing HFNC flow rate, and was highly variable between airway replicas. Higher pressures were measured for air versus heliox. For air supplied at 2 l/min/kg, average airway pressures in excess of 4 cm H2O were generated, with positive end-expiratory pressure (PEEP) ranging from 2.5 to nearly 12 cm H2O across the replicas. A predictive correlation for PEEP was proposed based on supplied gas density and flow velocities exiting the cannula and nares, and was able to account for a portion of variability between airway replicas (R2 = 0.913). Additionally, PEEP was well correlated with, and predictive of, expiratory peak pressure (R2 = 0.939) and average inspiratory pressure (R2 = 0.944).

Removal of per- and polyfluoroalkyl substances (PFASs) in a full-scale drinking water treatment plant: Long-term performance of granular activated carbon (GAC) and influence of flow-rate

Per- and polyfluoroalkyl substances (PFASs) have been ubiquitously detected in drinking water which poses a risk for human exposure. In this study, the treatment efficiency for the removal of 15 PFASs was examined in a full-scale drinking water treatment plant (DWTP) in the City of Uppsala, Sweden, over a period of two years (2015–2017). Removal of the five frequently detected PFASs was influenced by the total operation time of granular activated carbon (GAC) filters, GAC type and surface loading rate. The average removal efficiency of PFASs ranged from 92 to 100% for “young” GAC filters and decreased to 7.0–100% for “old” GAC filters (up to 357 operation days, 29 300 bed volumes (BV) treated). Flow-rates were adjusted in two full-scale GAC filters of different operational age to examine the removal of PFAS and organic matter depending on GAC operational age and operating flow. The decrease in flow-rate by 10 L s−1 from 39 to 29 L s−1 led to an average increase of 14% and 6.5% in total PFAS removal efficiency for an “old” (264 operation days, 21 971 BV treated) and a “young” GAC filter (63 operation days, 5 725 BV treated), respectively. A cost-analysis for various operation scenarios illustrated the dominating effect of treatment goals and costs for GAC regeneration on overall GAC operation costs. The unit costs for GAC filters ranged from 0.08 to 0.10 € m−3 water treated and 0.020-0.025 € m−3 water treated for a treatment goal of 10 ng L−1 and 85 ng L−1, respectively, for ∑11PFAS. Furthermore, it was concluded that prolonging the GAC service life by lowering the flow-rates after reaching the treatment goal could lead to a 26% cost-deduction. The results and methods presented in this study give drinking water providers valuable tools for the operation of a full-scale treatment train for the removal of PFAS in contaminated raw water.

Study on the Performance of a Swirl Tube Column

A column is an important heat and mass transfer equipment, which can be used for distillation, absorption, gas stripping, extraction and other transfer separation process. The commonly used columns include plate columns and packed columns, which are operated under the gravity and have the problems of flooding, furrow flow or bias flow. In this paper, a new column, the swirl tube column, is presented. The swirl tube column is firstly combined super-gravity field (centrifugal force field) with column equipment to enhance mass transfer and absorption process. Through the full-field simulation of a two-stage swirl tube column and experiment, the fluid mechanics performance such as the velocity field and pressure field, pressure drop and flooding critical condition in the swirl tube column, as well as the influence of flowrate and gas-liquid ratio on the absorption performance are studied. Results show that the swirl tube in the column can generate swirling flow, and the flooding problem can be effectively avoided by properly controlling the ratio of liquid to gas, and the absorbing efficiency of the one-staged swirl tube column can reach more than 61%. It is an innovation structural optimization of traditional column equipment. Which has high research and industrial production value.

Release kinetics from oral thin films: Theory and experiments

In this work, a new millifluidic flow-through device is proposed for drug release studies from oral strips. The flow-through device mimics mouth physiological conditions thanks to the laminar tangential solvent flow, flow rates order of 1mL/min and low hold-up volume (1cm3).Drug release experiments have been performed on HPMC K15M thin films loaded with methyl orange with different initial drug loadings. A detailed analysis of data reproducibility and influence of flow-rates, film thickness and drug dosage on release curves is presented.A two-dimensional moving boundary model, describing drug transport in the swelling film and in the solvent flow channel is presented and solved numerically by FEM (finite elements method).The theoretical model strongly supports the experimental observation that the time scales for complete drug release are significantly longer than expected when fluid dynamical conditions (close to mouth in-vivo conditions) are properly implemented in the experimental apparatus, and properly accounted for in the numerical modelling.

In Tube Integrated Electronic Nose System on a Flexible Polymer Substrate

The fabrication of electronic devices, such as gas sensors on flexible polymer substrates, enables the use of electronics in applications where conventional devices on stiff substrates could not be used. We demonstrate the development of a new intra-tube electronic-nose (e-nose) gas sensor device with multiple sensors fabricated and integrated on a flexible substrate. For this purpose, we developed a new method of fabricating a sensor array of four gas sensors on a flexible polymer substrate. The method allowed the use of lithography techniques to pattern different polymers with a broad range of solubility parameters. Conductive polymer composites were used as a gas sensitive layer due to the high stretchability of the material. Each of the 30 e-nose devices on one substrate was designed to fit on a polymer strip with a width of 2 mm. A single e-nose strip was successfully integrated into the inlet tube of a gas-measurement apparatus with an inner-tube diameter of 3 mm. Using the e-nose, we were able to differentiate between four different volatile solvent vapors. The tube-integrated e-nose outperformed a chamber-integrated e-nose of the same type in terms of response time and flow-rate influences. The sensor array inside the tube showed a faster response time and detected short pulses of analyte exposure compared to the same sensor array outside of the tube. We measured gas flow rates from 1,000 to 30 sccm without significant changes in sensor performance using this intra-tube e-nose prototype. The tube could be bent to radii <15 mm with a sensor performance similar to an unbent sensor.

Flow Rate's Influence on Low Temperature Silicon Oxide Deposited by Atmospheric Pressure Plasma Jet for Organic Thin Film Tranisitor Application

Low temperature processes and high quality gate insulator are very important for organic thin film transistors (OTFTs). We utilized atmospheric pressure plasma jet (APPJ) to deposit silicon oxide as gate insulator of OTFTs at low temperature. We found carry gas's flow rate would influence the deposition mechanism which lead to influence surface roughness and film quality. Leakage current density of our proposed silicon oxide was about 2.53 E-8 A/cm2 at 0.5 MV/cm. Our proposed OTFTs shows a low subthreshold swing of only 700 mV/dec., a low threshold voltage of -0.8 V, a low operation voltage of -2 V. The low-voltage OTFTs would reduce the power consummation of flexible display.

Flow Rate's Influence on Low Temperature Silicon Oxide Deposited by Atmospheric Pressure Plasma Jet for Organic Thin Film Tranisitor Application

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Characterization of amylose affinity membranes through adsorption of pure recombinant MBP-intein-CBD: equilibrium and kinetics data

Pure MBP-intein-CBD has been used as model protein in adsorption stages on amylose affinity membranes. Equilibrium data have been obtained and fitted to the Langmuir isotherm, and the model parameters have been estimated. The influence of flowrate on adsorbed protein has been investigated using a continuous flow system. Steady state data have been then compared with the equilibrium curve previously obtained. The kinetic constants of the binding and desorption reactions have been estimated using a kinetic model accounting for both adsorption and desorption reactions. Mass transfer effects within the liquid phase have been found negligible. Values of kinetic parameters have been obtained in the operative conditions of both adsorption and elution steps. The influence of NaCl concentration on the values of k 1 and k 2 can be roughly estimated. The knowledge of these parameters, together with the maximum binding capacity allows for the scale-up design of an affinity membrane chromatographic column.

Experimental Micro-modeling and Numerical Simulation of Gas/Water Injection/Withdrawal Cycles as Applied to Underground Gas Storage Reservoir

SUMMARY This paper presents the results of an experimental and theoretical study of mechanisms responsible for the evolution and structure of the gas bubble during air-water injection-withdrawal cycles in 2D glass micromodels. Wetting films located in the corners of throat section conduct flow. Wetting film flow generates gas loop structure which increases injection efficiency and also the amount of trapped gas during withdrawal. During the next injection, blob distribution and wetting film flow induce a quicker breakthrough. Using a network simulator which takes into account wetting film flow, the influence of flow-rate on cycling is highlighted

Determination of the loss of stationary phase in gas-liquid chromatography from the change in retention volume

The effects of liquid-phase bleeding on the determination of gas chromatographic quantities are important, especially when using a high-precision gas chromatograph. Equations are developed in which changes in solute retention volume are used to correct for losses of stationary phase. The method gives the best precision when frequent measurements are made of solute retention volume and of the corresponding total volume of carrier gas that has passed through the column, and is therefore most suited to chromatographs coupled to an on-line computer. It has been found that the change in solute retention volume with accumulated carrier gas flow is constant with n-octadecane and 3,3′-oxydipropionitrile as stationary phases; no influence of flow-rate has been observed in the range 25–85 ml/min. Pressures of octadecane at 333 and 371 °K, and of 3,3′-oxydipropionitrile at 373 °K, have been calculated from the bleeding. The values obtained agree well with literature values for the saturated vapour pressure. Thus, in many cases, the change in volume of the stationary phase with accumulated flow can be calculated from the saturation vapour pressure.