Abstract:In this work, suspensions of Fe 3 O 4 , CNT, SiO 2 , and Al 2 O 3 nanoparticles in distilled water are produced and tested as new absorbents in a gas−liquid hollow fiber membrane contactor to investigate the effect of nanoparticles on the rate of mass transfer during CO 2 absorption. For this purpose, a pilot-scaled hollow fiber membrane contactor was constructed. A gas mixture was passed through the shell-side, and the nanofluid flowed cocurrently through the lumen side of the fibers. The effects of different… Show more
“…Figure 3 implies the presence of a great agreement between the measured data and modeling/simulation results for CO 2 molecular separation percentage using CNTs water-based nanofluid with an average deviation (AD) of about 6%. Figure 3 Validation of modeling/simulation results with existed experimental data provided by Peyravi et al in various gas flow rates (Q g ) 16 . The amount of CNTs loading = 0.1 wt% CO 2 , Inlet CO 2 concentration = 9,900 ppm, Q l = 7 L h −1 , T = 303 K, P = 0.3 bar.…”
Section: Resultsmentioning
confidence: 85%
“…To verify the validity of modeling/simulation results, they are compared with existed experimental data reported in literature. Indeed, the CFD-based results of CO 2 sequestration percentage using CNTs water-based nanofluid are compared with measured data provided by Peyravi et al in various gas flow rates (Q g ) 16 . The sequestration yield of CO 2 molecules applying distilled water and CNTs water-based nanofluid is presented in the following equation, where C and Q are respectively expressed as the concentration of CO 2 in the gas phase and volumetric gas flow rate 44,48,54 : Figure 3 implies the presence of a great agreement between the measured data and modeling/simulation results for CO 2 molecular separation percentage using CNTs water-based nanofluid with an average deviation (AD) of about 6%.…”
Section: Resultsmentioning
confidence: 99%
“…Validation of modeling/simulation results with existed experimental data provided by Peyravi et al in various gas flow rates (Q g )16 . The amount of CNTs loading = 0.1 wt% CO 2 , Inlet CO 2 concentration = 9,900 ppm, Q l = 7 L h −1 , T = 303 K, P = 0.3 bar.…”
mentioning
confidence: 89%
“…It has been reported that the absorption rate of the gas solutes in MGS systems can be improved by using nanofluids. For example, Peyravi et al experimentally investigated the CO 2 absorption enhancement by introducing various nanofluids (Fe 3 O 4 , CNTs, Al 2 O 3 , and SiO 2 ) using a HFMC 16 . The authors found that Al 2 O 3 , CNTs, Fe 3 O 4 , and SiO 2 nanoparticles could increase the absorption rate of CO 2 by 44, 38, 25, and 3%, respectively.…”
The use of nanofluids has been recently of great interest to separate acidic contaminants such as CO 2. The main objective of this research is to assess the influence of carbon nanotubes (CNTs) addition to distilled water on enhancing the CO 2 molecular separation through a porous membrane contactor (PMC). For this aim, a comprehensive model is developed based on non-wetted and counter-current operational modes to evaluate the principal mass and momentum transport equations in tube, membrane and shell compartments of PMC. Consequently, a CFD-based axisymmetrical simulation is implemented according to finite element technique (FET) to prognosticate the results. It is found from the results that the addition of 0.1 wt% carbon nanotubes (CNTs) particles to water significantly enhances the mass transfer and consequently the CO 2 molecular separation efficiency from 38 to 63.3%. This considerable enhancement can be justified due to the existence of two momentous phenomena including Brownian motion and Grazing effect, which enhance the mass transport of CO 2 molecules in the PMC. Moreover, the effect of CNTs concentration, some membrane's parameters such as number of hollow fibers and porosity and also some module's design parameters including module radius and length on the CO 2 separation performance are investigated in this paper as another highlight of the current work. Sustainable anthropogenic emission of greenhouse contaminants such as CO 2 and its pernicious influence on the atmosphere (i.e., global warming and acid rains) has been a global concern in developed and developing countries 1,2. Globally, it is estimated that several billion tons of CO 2 are being emitted into the atmosphere each year through burning fossil fuels 3. Human's industrial activities are verified to be the main reason for the increase in CO 2 amount and disturbance in atmospheric natural balance. Thus, it is vitally important to develop viable procedures for CO 2 sequestration 4. There are different processes for separation and removal of CO 2 from gas streams which need to be improved to obtain more efficient processes. Traditional techniques such as pressure swing adsorption, bubble columns, venture scrubbers, spray towers, and packed towers have recently been applied to eliminate CO 2 contaminants from gas streams. Apart from the superb advantages of conventional methods, such techniques suffer from disparate difficulties such as high capital/operating costs, risk of liquid overflow, frothing, entrainment, and channeling 5,6. The combination of gas absorption and membrane separation processes formed a modern technique which is known as the membrane gas separation (MGS) system. This technique is able to overcome the
“…Figure 3 implies the presence of a great agreement between the measured data and modeling/simulation results for CO 2 molecular separation percentage using CNTs water-based nanofluid with an average deviation (AD) of about 6%. Figure 3 Validation of modeling/simulation results with existed experimental data provided by Peyravi et al in various gas flow rates (Q g ) 16 . The amount of CNTs loading = 0.1 wt% CO 2 , Inlet CO 2 concentration = 9,900 ppm, Q l = 7 L h −1 , T = 303 K, P = 0.3 bar.…”
Section: Resultsmentioning
confidence: 85%
“…To verify the validity of modeling/simulation results, they are compared with existed experimental data reported in literature. Indeed, the CFD-based results of CO 2 sequestration percentage using CNTs water-based nanofluid are compared with measured data provided by Peyravi et al in various gas flow rates (Q g ) 16 . The sequestration yield of CO 2 molecules applying distilled water and CNTs water-based nanofluid is presented in the following equation, where C and Q are respectively expressed as the concentration of CO 2 in the gas phase and volumetric gas flow rate 44,48,54 : Figure 3 implies the presence of a great agreement between the measured data and modeling/simulation results for CO 2 molecular separation percentage using CNTs water-based nanofluid with an average deviation (AD) of about 6%.…”
Section: Resultsmentioning
confidence: 99%
“…Validation of modeling/simulation results with existed experimental data provided by Peyravi et al in various gas flow rates (Q g )16 . The amount of CNTs loading = 0.1 wt% CO 2 , Inlet CO 2 concentration = 9,900 ppm, Q l = 7 L h −1 , T = 303 K, P = 0.3 bar.…”
mentioning
confidence: 89%
“…It has been reported that the absorption rate of the gas solutes in MGS systems can be improved by using nanofluids. For example, Peyravi et al experimentally investigated the CO 2 absorption enhancement by introducing various nanofluids (Fe 3 O 4 , CNTs, Al 2 O 3 , and SiO 2 ) using a HFMC 16 . The authors found that Al 2 O 3 , CNTs, Fe 3 O 4 , and SiO 2 nanoparticles could increase the absorption rate of CO 2 by 44, 38, 25, and 3%, respectively.…”
The use of nanofluids has been recently of great interest to separate acidic contaminants such as CO 2. The main objective of this research is to assess the influence of carbon nanotubes (CNTs) addition to distilled water on enhancing the CO 2 molecular separation through a porous membrane contactor (PMC). For this aim, a comprehensive model is developed based on non-wetted and counter-current operational modes to evaluate the principal mass and momentum transport equations in tube, membrane and shell compartments of PMC. Consequently, a CFD-based axisymmetrical simulation is implemented according to finite element technique (FET) to prognosticate the results. It is found from the results that the addition of 0.1 wt% carbon nanotubes (CNTs) particles to water significantly enhances the mass transfer and consequently the CO 2 molecular separation efficiency from 38 to 63.3%. This considerable enhancement can be justified due to the existence of two momentous phenomena including Brownian motion and Grazing effect, which enhance the mass transport of CO 2 molecules in the PMC. Moreover, the effect of CNTs concentration, some membrane's parameters such as number of hollow fibers and porosity and also some module's design parameters including module radius and length on the CO 2 separation performance are investigated in this paper as another highlight of the current work. Sustainable anthropogenic emission of greenhouse contaminants such as CO 2 and its pernicious influence on the atmosphere (i.e., global warming and acid rains) has been a global concern in developed and developing countries 1,2. Globally, it is estimated that several billion tons of CO 2 are being emitted into the atmosphere each year through burning fossil fuels 3. Human's industrial activities are verified to be the main reason for the increase in CO 2 amount and disturbance in atmospheric natural balance. Thus, it is vitally important to develop viable procedures for CO 2 sequestration 4. There are different processes for separation and removal of CO 2 from gas streams which need to be improved to obtain more efficient processes. Traditional techniques such as pressure swing adsorption, bubble columns, venture scrubbers, spray towers, and packed towers have recently been applied to eliminate CO 2 contaminants from gas streams. Apart from the superb advantages of conventional methods, such techniques suffer from disparate difficulties such as high capital/operating costs, risk of liquid overflow, frothing, entrainment, and channeling 5,6. The combination of gas absorption and membrane separation processes formed a modern technique which is known as the membrane gas separation (MGS) system. This technique is able to overcome the
“…By increasing the liquid flow rate, the liquid phase boundary layer decreases. As such, the interface of liquid–gas could be maintained at a fresh absorbent, which significantly enhances the absorption efficiency of CO 2 . However, despite of the increase in liquid flow rate at the highest temperature of 45°C, the k l declines significantly.…”
Today, CO2 separation is very important, both as an environmental issue and also in various industries. In this study, the water‐based nanofluid of NaP zeolite nanocrystals and 1‐dodecyl‐3‐methylimidazolium chloride ([C12mim][Cl]) ionic liquid were mixed and tested experimentally for CO2 absorption in an isothermal high pressure cell equipped with magnetic stirring. Zeolite nanocrystals were synthesized via the hydrothermal approach and characterized. A series of experiments were performed at different conditions to investigate the impact of various parameters, including nanoparticle type, nanoparticle concentration, stabilizer concentration, and the vessel's initial pressure, on CO2 solubility. It was found that 0.02 wt.% of zeolite nanoparticles, 0.4 wt.% of [C12mim][Cl] ionic liquid, and 0.05 wt.% of sodium dodecyl benzene sulphonate (SDBS) in nanofluids result in higher absorption of CO2 compared to other concentrations. Furthermore, CO2 absorption was increased by increasing ionic liquid and surfactant concentration up to a certain value near critical micelle concentration, but after that the CO2 absorption was decreased. The overall CO2 absorption enhancement at 20 bar for 0.02 wt.% zeolite and ZnO water‐based nanofluids with 0.4% [C12mim][Cl] ionic liquid and 0.02 wt.% SDBS were 26.9%, 21.5%, 21.2%, and 17% in comparison to pure water, respectively. In an absorption process using nanofluids, besides the influence of the mentioned parameters, the micro‐convection caused by Brownian motion and the grazing effect of nanoparticles should be noted. Considering the micro‐convection and grazing effects, a theoretical model should take into account the Brownian motion and grazing effects on the mass transfer rate in nanofluids to investigate the absorption enhancement by nano‐particles.
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