Absorption Rate Of Carbon Dioxide Research Articles

Quantification of Aucuba japonica Thunb. CO2 absorption for various moisture conditions

The aim of the study was to determine the effect of insufficient moisture supply on the absorption of carbon dioxide by Aucuba japonica Thunb., as well as the dynamics of the growth of phytomass and the amount of CO 2 absorbed by A. japonica at optimal moisture supply during the active growing season from May to September on the Southern coast of the Crimea, a region of dry subtropics. It was revealed that the carbon dioxide absorption rate and the growth rate of A. japonica phytomass begin to decrease when the soil moisture was below 60% of field capacity (FC). The maximum value of CO 2 absorption intensity by A. japonica leaves at optimal soil water supply was 0.95 mg/(cm 2 x day). At a soil water content of 15% FC, the CO 2 absorption rate decreased to 20% of the maximum CO2 absorption value, and the leaf biomass growth rate decreased by 25 times. The maximum monthly average amount of absorbed CO 2 during the period of active vegetation of the A. japonica plant was recorded in May and amounted to 0.83 mg/(cm 2 x day), and the maximum monthly average rate of increase in the volume of leaf phytomass (0.36 cm 3 /day) was noted in August. The phase of the most active growth of A. japonica phytomass occurs in August. It is possible to increase the growth rate of phytomass in August by lowering the air temperature, as well as increasing the relative humidity through drip irrigation.

APPLICATION OF PHYTOTECHNOLOGY IN DETERMINING PLANT SPECIES FOR GREENSPACE IN THE CITY OF PALANGKA RAYA

This study aims to obtain scientific evidence for plant species in their ability to absorb carbon dioxide, to rank plants based on their ability to absorb carbon dioxide, and to obtain the format of area and distribution. Experimental methods of plant species based on the types that have been commonly used as urban greening, and traditionally based plant species. The results obtained indicate that plant-based types of local wisdom are scientifically proven to show superiority in the rate of carbon dioxide absorption. There are plant species, both local wisdom and urban greening plants, which have specific fluctuating absorption rates.

Carbon dioxide chemical absorption in non-aqueous solvents by the presence of water

Abstract Present work analyzes the role of water in a gas–liquid–liquid absorber using a non-soluble amine (octylamine) in water. The presence of water causes an enhancement in carbon dioxide loading and absorption rate in comparison with the use of the organic solvent. Several issues have been analyzed in present research work: influence of gas flow-rate, water and amine concentration, type of organic solvent and solvent regeneration. The analysis of experimental data and speciation studies by using nuclear magnetic resonance allows to understand the overall behavior with the accumulation of reaction products in the organic phase by the formation of water-in-oil microemulsion. The accumulation of reaction products allows to decrease the solvent flow rate that must be regenerated and it can decrease the cost of this type of operation.

Comparison of Carbon Dioxide Absorption Rates in Gynecologic Laparoscopy with a Valveless versus Standard Insufflation System: Randomized Controlled Trial

Study ObjectiveThe primary objective was to compare carbon dioxide (CO2) absorption rates in patients undergoing gynecologic laparoscopy with a standard versus valveless insufflation system (AirSeal; ConMed, Utica, NY) at intra-abdominal pressures (IAPs) of 10 and 15 mm Hg. Secondary objectives were assessment of surgeons’ visualization of the operative field, anesthesiologists’ ability to maintain adequate end-tidal CO2 (etCO2), and patients’ report of postoperative shoulder pain. DesignA randomized controlled trial using an equal allocation ratio into 4 arms: standard insufflation/IAP 10 mm Hg, standard insufflation/IAP 15 mm Hg, valveless insufflation/IAP 10 mm Hg, and valveless insufflation/IAP 15 mm Hg. SettingSingle tertiary care academic institution. PatientsWomen ≥ 18 years old undergoing nonemergent conventional or robotic gynecologic laparoscopic surgery. InterventionsA standard or valveless insufflation system at IAPs of 10 or 15 mm Hg. Measurements and Main ResultsOne hundred thirty-two patients were enrolled and randomized with 33 patients per group. There were 84 robotic cases and 47 conventional laparoscopic cases. CO2 absorption rates (mL/kg*min) did not differ across groups with mean rates of 4.00 ± 1.3 in the valveless insufflation groups and 4.00 ± 1.1 in the standard insufflation groups. The surgeons’ rating of overall visualization of the operative field on a 10-point Likert scale favored the valveless insufflation system (median visualization, 9.0 ± 2.0 cm and 9.5 ± 1.8 cm at 10 and 15 mm Hg, respectively) over standard insufflation (7.0 ± 3.0 cm and 7.0 ± 2.0 cm at 10 and 15 mm Hg, respectively; p <.001). The anesthesiologists’ ability to maintain adequate etCO2 was similar across groups (p = .417). Postoperative shoulder pain scores were low overall with no significant difference across groups (p >.05). ConclusionCO2 absorption rates, anesthesiologists’ ability to maintain adequate etCO2, and postoperative shoulder pain did not differ based on insufflation system type or IAP. Surgeons’ rating of visualization of the operative field was significantly improved when using the valveless over the standard insufflation system.

Study on carbonation technology of alkaline uranium mother liquor

The characteristics of the main components of alkaline uranium mother liquor: A small amount of uranium, a certain amount of hydroxide, and a large amount of carbonate. Through the analysis of chemical reaction and diffusion about transfer between mother liquor and CO2, the influencing factors of mother liquor carbonation were determined: Gas-liquid transfer, reactant concentration, reaction temperature, etc. Tower counter-current was selected to investigate the influence of different types of fillers on carbonation effect. The stainless steel triangular spiral filler was optimized. The filling tower device for carbonation of uranium mother liquor was finalized, which greatly improved the gas-liquid distribution efficiency and carbon dioxide absorption rate. The effect of residual alkali concentration and reaction temperature of mother liquor on carbonation effect was investigated. The technology realizes the conversion of sodium hydroxide to sodium carbonate in the mother liquor. When sodium carbonate is converted to sodium bicarbonate, it can be converted to the saturated concentration of sodium bicarbonate, and CO2 is absorbed in both stages. The device can be used to control the degree of carbonation of the mother liquor according to the demand, and be returned as leaching agent or eluent, realized the full reuse of the remaining alkali in the mother liquor.

Gamification of global climate change: an experimental analysis

AbstractThe global climate system poses important challenges for the perception and understanding of its functioning from policymakers and the general public. The aim of the paper is to model through gamification, the evolution of understanding regarding the dynamics of climate change and climate change adaptation. Using a framework with repeated feedback loops, the impact of the rate of carbon dioxide absorption by natural ecosystems, the stochastic nature of economic systems and the stochastic and irreversible nature of global climate are analyzed, with the Dynamic Climate Change Simulator with Stochastic and Irreversible Climate Change. The simulator game models one control variable, carbon dioxide emissions and one stock variable, carbon dioxide concentrations in the atmosphere. In addition, the rate of carbon dioxide absorption by natural ecosystems is modeled, with business cycle shocks and climate change tipping points. The ability to control carbon dioxide concentrations to a goal level is evaluated and policy insights are provided about how learning about the dynamics of the Earth’s climate through gamification can be advanced.

Absorption performance of carbon dioxide in 4-Hydroxy-1-methylpiperidine + aminoethylethanolamine aqueous solutions: Experimental measurement and modeling

In this study, new experimental data was obtained for the solubility and absorption rate of carbon dioxide in 2, 3 and 4 M of 4-Hydroxy-1-methylpiperidine (HMPD) aqueous solution and the effect of addition of 0.5 and 1.5 M aminoethylethanolamine (AEEA) on it. Experimental data was measured in a bath reactor within the temperature range of 303.15–373.15 K and pressure range of 28.3–1980.3 kPa. The solution viscosity was measured at different temperature and concentration conditions. Response surface methodology (RSM) was used for modeling and optimization of the CO2 loading and absorption rate.The results of RSM showed that AEEA concentration and partial pressure of CO2 have the maximum impact on absorption rate and CO2 loading, respectively. The maximum absorption rate and CO2 loading occurred at 2M HMPD+1.35M AEEA in 320.15K and 1980.3 kPa. The measured experimental values revealed that HMPD + AEEA solution has a more desirable absorption rate, CO2 loading and oxidative degradation in comparison to methylediethanolamine(MDEA) + piperazine(PZ) aqueous solution.

CO2 absorption with tri-n-butylamine in GL and GLL systems

Present research work is focused on the analysis of carbon dioxide chemical absorption with tri-n-butylamine (TBA) due to the suitable behavior previously shown by some tertiary amines (mainly methyldiethanolamine). TBA has a negative characteristic due to its low solubility in water that implies the use of an organic co-solvent using several alcohols in present work. Ethanol showed the best experimental results in carbon dioxide absorption rate and loading. A decrease in carbon dioxide loading in comparison with tertiary amines in aqueous solution was observed due to the high chemical interactions between water and ethanol molecules. It was confirmed using monoethanolamine + water + ethanol as chemical solvent and its comparison with the liquid phase in the absence of ethanol. A very important issue for TBA-solvent is the dramatic decrease in solvent degradation under stripping experimental conditions. This fact reduces until a minimum the solvent make-up flow-rate with a very important decrease in the overall process cost.

Absorption rates of carbon dioxide in amines in hydrophilic and hydrophobic solvents

The rate of absorption of CO2 into amines in hydrophilic and hydrophobic solvent mixtures was studied in this work using a stopped-flow apparatus and a stirred-tank reactor. Monoethanolamine (MEA, primary amine) and N-methyl benzylamine (NMBZA, aromatic secondary amine) are chosen for this study and diluted in hydrophobic or hydrophilic solvents at different temperatures (295–343 K) and concentrations (0.01–4 kmol.m−3). It was found that the reaction rate between the secondary amine and CO2 in water is faster than the reaction with the linear primary amine (MEA); however, in an ethereal hydrophobic non-aqueous system the NMBZA-CO2 reaction is slower than the reaction of CO2 with MEA. With respect to amine, the reaction orders were found to be 0.9 and 1.2 for hydrophilic systems (MEA + H2O, NMBZA + H2O). For hydrophobic system they were found to be 0.6 and 2.7 (NMBZA + ethereal hydrophobic solvent, NMBZA + MePhOH + ethereal hydrophobic solvent). When amine was mixed with hydrophilic solvent (H2O), the activation energy of amine (NMBZA) to react with CO2 was found to be 27.66 kJ.mol−1 and decreased to 10.37 kJ.mol−1 when mixed with hydrophobic solvent (ethereal hydrophobic solvent). The activation energy of hydrophobic solvent was found to increase by adding an alcohol to the solvent (MePhOH + ethereal hydrophobic solvent). Both the zwitterion and termolecular mechanism were applied to the experimental data. It was found that deprotonation of the zwitterion and deprotonation of the loosely bound complex was the rate limiting step for the zwitterion and termolecular mechanism, respectively.Additionally, activators such as water, piperazine (PZ), and 4-hydroxy piperidinol (HPIP) were added to the ethereal hydrophobic non-aqueous solvent to determine the effect on the reaction rate. It was found that the water- and amine-based activators lead to an increase in the observed reaction rates as the concentration of the activators increased. The reaction of NMBA with CO2 and PZ exhibited a higher reaction rate but the PZ was insoluble in the non-aqueous NMBZA system, whereas HPIP remained soluble and offered a similar reaction rate. The activation energy of ethereal hydrophobic non-aqueous solvent to react with CO2 increased from 27.98 to 32.83 kJ.mol−1 by adding PZ and 33.51 kJ.mol−1 by HPIP and remained by adding H2O (26.78 kJ.mol−1). From this work, it was found that the non-aqueous solvent plays an important role in the reaction rate of CO2 with amines. Activators and solvents can be selected to increase the reaction rate with CO2.

Investigation of the effects of nanoparticle size on CO2 absorption by silica-water nanofluid

Abstract Using nanofluids as absorbent is a novel technique for the enhancement of mass transfer in gas absorption process. In this article, a bubble column absorption system was used to investigate the effects of nanoparticle size on carbon dioxide (CO2) absorption in silica/water nanofluid. In the experimental setup, CO2 was injected as frequent bubbles from the bottom of the column containing silica/water nanofluid with different particle sizes of 10.6, 20, 38.6, and 62 nm. The rate of carbon dioxide absorption in silica-water nanofluid increased with nanoparticle size and maximum absorption rate or molar flux was obtained at 0.01 wt% of nanoparticles for all nanofluids with different nanoparticles sizes. Mass transfer parameters including diffusion coefficient, renewal surface rate and thickness of diffusion layer within liquid was also investigated at different nanoparticle sizes. The results show that by increment of nanoparticle size, the renewal surface rate increased while diffusivity and liquid-film thickness decreased. Consequently, Mass transfer coefficients increased by increment of nanoparticle size. Finally a new correlation was proposed incorporating nanoparticle diameter for estimating mass transfer coefficient.

99 - A Comparison of Carbon Dioxide (CO2) Absorption Rates in Gynecologic Laparoscopy with a Valveless Insufflation System Versus Standard Insufflation System at Intra-Abdominal Pressures of 10 mmHg and 15 mmHg – A Randomized Controlled Trial

Study Objective: To compare CO2 absorption rates, surgeons' visualization of operative field, anesthesiologists' perception of difficulty maintaining adequate end-tidal carbon dioxide (etCO2) and postoperative shoulder pain in gynecologic laparoscopy with a valveless insufflation system (AirSeal® valveless system) versus standard insufflation system at intra-abdominal pressures (IAP) of 10 and 15 mmHg.

A carbonic anhydrase inspired temperature responsive polymer based catalyst for accelerating carbon capture

A temperature responsive carbonic anhydrase mimicking compound (PNiPAm-co-CyclenZn) was synthesised and characterized to assess its potential as a rate promoter for carbon dioxide (CO2) capture using solvent absorption. Development of novel rate promoters, such as the catalytic polymer discussed in this study, can improve reaction kinetics and reduce the cost of CO2 capture. Results showed that the lower critical solution temperature (LCST) of PNiPAm-co-CyclenZn is 33.7°C which is close to the physiological temperature. Above the LCST, PNiPAm-co-CyclenZn undergoes a phase transition from a swollen hydrated state to a shrunken dehydrated state. This property can potentially enable easy separation of PNiPAm-co-CyclenZn from the CO2 loaded solution exiting the absorber column so that it does not enter the high temperature stripping column. In the reaction between CO2 and H2O, the catalysis coefficient at 298K of PNiPAm-co-CyclenZn was determined to be 380±20M−1s−1 at a pH of 7.36 and 2330±40M−1s−1 at a pH of 9.06. Arrhenius fitting of the catalysis coefficients showed an activation energy of 60±2kJ/mol at pH of 7.36. This study presents the first example of a temperature responsive polymeric catalyst for carbon dioxide absorption. The catalyst was developed with the aim of increasing the absorption rates of carbon dioxide in bicarbonate forming amine solutions and carbonate solvents that have slow absorption kinetics.

Solubility of CO2 in aqueous solutions of DAMP+MDEA, DAMP+MEA, DAH+MDEA and DAH+MEA

The main goal of this research is to investigate absorption rate and capacity of carbon dioxide in aqueous mixtures of DAMP(1,5-Diamino-2-methylpentane)+MDEA(Methyl-diethanolamine), DAMP+MEA(Monoethanolamine), DAH(1,6-Diaminohexane)+MDEA and DAH+MEA in an isothermal stirred batch reactor. The experiments are designed in temperature ranging from 30 to 50 °C, at low pressure and various molar ratios. The results show that although there is an interaction between diamine and conventional amines at low diamine concentration, after a minimum absorption point, increasing DAMP and DAH concentration in conventional amines increases absorption capacity of solutions in all temperatures. Then, a rate equation is developed to predict absorption rate of aqueous solution of DAMP based on Zwitterion mechanism. The kinetic constant and order of reaction are determined considering the absolute difference between measured and predicted rate as the objective function. The results show that the reaction is first order with respect to amine concentration and third order in overall.

Controlling the size and morphology of precipitated calcite particles by the selection of solvent composition

Precipitated calcium carbonate is used asan additive in the manufacture of many products. Particles with specific characteristics can be obtained by the selection of precipitation conditions, including temperature and the composition of solvent. In this work, calcium carbonate particles were obtained in the reaction of calcium hydroxide with carbon dioxide at 65°C. Initial Ca(OH)2 suspensions were prepared in pure water and aqueous solutions of ethylene glycol or glycerol of the concentration range up to 20% (vol.). The course of reaction was monitored by conductivity measurements. Precipitated solids were analyzed by FTIR, XRD, SEM and the particles size distribution was determined by a laser diffraction method. The adsorption of ethylene glycol or glycerol on the surface of scalenohedral and rhombohedral calcite was testes by a normal-phase high-performance liquid chromatography. The addition of organic solvents changed the viscosity of reaction mixtures, the rate of carbon dioxide absorption and the solubility of inorganic components and therefore influence calcium carbonate precipitation conditions. All synthesized calcium carbonate products were in a calcite form. Scalenohedral calcite crystals were produced when water was a liquid phase, whereas addition of organic solvents resulted in the formation of rhombo-scalenohedral particles. The increase in organic compounds concentration resulted in the decrease of mean particles size from 2.4µm to 1.7µm in ethylene glycol solutions and to 1.4µm in glycerol solutions. On the basis of adsorption tests, it was confirm that calcite surface interact stronger with glycerol than ethylene glycol. The interaction between scalenohedral calcite and used organic additives was higher in comparison to the pure rhombohedral form applied asa stationary phase.

Mass transfer and thermodynamic modeling of carbon dioxide absorption into MEA aqueous solution

Abstract In this research, thermodynamic and absorption rate of carbon dioxide in monoethanolamine (MEA) solution was investigated. A correlation based on both liquid and a gas phase variable for carbon dioxide absorption rate was presented using the π-Buckingham theorem. The correlation was constructed based on dimensionless numbers, including carbon dioxide loading, carbon dioxide partial pressure, film parameter and the ratio of liquid phase film thickness and gas phase film thickness. The film parameter is used to apply the effect of chemical reactions on absorption rate. A thermodynamic model based on the extended-UNIQUAC equations for the activity coefficients coupled with the Virial equation of state for representing the non-ideality of the vapor phase was used to predict the CO2 solubility in the CO2-MEA-H2O system. The average absolute error of the results for the correlation was 6.4%, which indicates the accuracy of the proposed correlation.

An Experimental Investigation of Reactive Absorption of Carbon Dioxide into an Aqueous NH3/H2O/NaOH Solution

In this research, the reactive absorption of carbon dioxide in an aqueous solution of NH3, H2O, and NaOH has experimentally been investigated. The experiments were carried out in an absorption pilot plant in different operational conditions. The composition and temperature of both gas and liquid phases were obtained during the column height. The concentration of molecular and ionic species in the liquid phase was calculated using the principles of electrolyte and Pitzer model. In the experiments, the effect of sodium hydroxide concentration on carbon dioxide absorption was considered. The results revealed that the concentrations of ionic and molecular species in the liquid phase drastically influence the absorption rate of carbon dioxide. Also, the results showed that the absorption rate of carbon dioxide was increased by increasing ammonia and sodium hydroxide concentration.

Carbon Capture from a Simulated Flue Gas Using a Rotating Packed Bed Adsorber and Mono Ethanol Amine (MEA)

In this paper new experimental data are presented on the rate of carbon dioxide absorption from a synthetic flue gas (67 vol% N2, 18 vol% O2 and 15 vol% CO2) in a rotating packed bed. The bed had an inner diameter of 80mm and an outer diameter of 300mm and operated at speeds of 600 – 1450rpm. The packing used was Expamet stainless steel mesh. The novelty of this work is that the gas phase was saturated with water vapour at 40˚C, as would be the case in CO2 capture from flue gas. Other investigations on carbon capture using a rotating packed bed reported in the literature have used dry gases. The solvents used in the experiments were monoethanolamine (MEA) solutions containing 30mass% MEA and 90mass% MEA. The rate of absorption was measured by analysing the CO2 content of the gas phase at the inlet and outlet of the rotating packed bed using an online CO2 meter. The pressure drop, power consumption and temperatures of the gas and liquid phases were measured as well. The measured overall gas phase mass transfer coefficient (KGa) was found to be in agreement with similar measurements from literature and ranged in value from 1.8 - 6.2 s-1. The concentration of MEA was found to have the largest effect on KGa followed by the liquid to gas mass flow ratio and the rotational speed.

The resilience of carbonic anhydrase enzyme for membrane-based carbon capture applications

A microbial carbonic anhydrase was immobilized onto the surface of hollow fiber membranes to enhance the absorption rate of carbon dioxide into an aqueous 30wt% potassium carbonate solvent at pH 10–12. The performance of the immobilized enzyme was investigated over long time frames to determine the suitability of this approach for post-combustion carbon capture. The immobilized enzyme was able to maintain activity for up to 80 days at 25°C even when initially exposed to pH 12, however lost activity rapidly when exposed to such high pH at 50°C and subsequently was completely deactivated within 4 days. The effect of sulfur dioxide and nitric oxide that are present in post-combustion flue gas streams was investigated by contacting enzyme immobilized onto flat planar membrane coupons directly with the dry gases and with solutions containing the anions associated with the gases, namely sulfate, sulfite, nitrate and nitrite. The immobilized enzyme maintained at least 80% of its activity even in the presence of 200mM of these anions or 500ppm of the dry gases. Our findings indicate that the enzyme is not significantly affected by these toxic gases or their associated anions. Rather, the combination of high pH and ionic strength of the solvent at a high absorption temperature causes a reduction in the enzyme activity and affects the performance of the absorption process.

Revitalization of air using a potassium superoxide plate in hypoxic space: Performance and kinetic model under natural convection conditions

Potassium superoxide-based oxygen supply systems demonstrate a tremendous potential for applications associated with mine emergency rescue. In this study, the air revitalization performance of a potassium superoxide plate operating under natural convection conditions was investigated by a series of passive tests in a sealed chamber. Reaction resistance analysis based on experimental data revealed that increasing air temperature and humidity accelerates oxygen generation but reduces the system respiratory quotient as a result of the increased resistance of internal diffusion. Increasing the amount of plates or using them in combination with a carbon dioxide absorption curtain is a practical, effective method for meeting requirements of both oxygen generation rate and system respiratory quotient in underground refuge. Kinetics model that predicted the mean oxygen generation rate, carbon dioxide absorption rate, system respiratory quotient and total thermal output (Q) was also derived from experimental data in this study. Predicted results were found to be in good agreement with experimental data. The proposed model can aid in the design of air revitalization systems used in refuge stations for underground mines.

Experimental study and modeling of CO2 absorption into diethanolamine solutions using stirrer bubble column

In this work, solubility and chemical absorption rate of carbon dioxide into aqueous solutions of diethanolamine (DEA) were studied in a stirred bubble column. In the experiments the effects of stirrer speed, amine concentration, CO2 partial pressure and CO2 loading on absorption rate and solubility were investigated. The experimental conditions are, amine concentration in range of 0.2–2.0M, CO2 partial pressures in range of 2.4–3.6kPa, stirrer speed in range of 0–600rpm, CO2 loading in range of 0.1–0.7mole of CO2 per mole of amine. The results showed that mass transfer flux and absorption percent of CO2 were varied in range of 34–59% and 0.35–4.32kmolm−2s−1, respectively. A thermodynamic model, based on Deshmukh and Mather model is proposed for the equilibrium solubility of CO2 in DEA solutions. It has been found that this model is able to estimate results which are close to the experimental data in terms of the total CO2 loadings of the solution. Predicted partial pressures of the CO2 over diethanolamine solution were also observed good deal with experimental data.