Membrane contactors are a hybrid technology that incorporates the advantages of both solvent absorption and membrane separation. Porous and asymmetric composite membrane contactors have been studied for CO2 absorption, and both configurations are susceptible to pore wetting. This results in a significant reduction in the mass transfer efficiency. As such, regeneration methods to remove entrained liquids from the contactors are of interest. In this work, four regeneration protocols are trialled for a porous poly tetrafluoroethylene (PTFE) contactor and a thin film composite poly(1-trimethylsilyl)-1-propyne (PTMSP) contactor. It was found that air and vacuum drying at elevated temperatures increased the overall mass transfer coefficient of both contactors compared to the wetted state, but did not return either to their original performance. In addition, both contactors experienced rapid rewetting of the pores. Prewashing with methanol before air drying at elevated temperature produced the greatest improvement in overall mass transfer for the regenerated contactors. This was attributed to methanol miscibility with the water in the pores reducing the capillary pressure experienced during drying, as well as methanol swelling the PTMSP layer. However, original functionality was not achieved for either contactors and both continued to experience wetting over time, though at a slower rate than with non-methanol wash regeneration protocols.

The aqueous ammonia process is a promising CO2 capture technology for post-combustion flue gas treatment. The most attractive advantage of this technology is a relative low cost of solvent regeneration compared to traditional amine solutions. In this work, the absorption of CO2 into aqueous ammonia was experimentally studied in a gas/liquid contactor fitted with hollow fiber PTFE membranes at ambient temperature. The absorption performance was evaluated in terms of K(G)a(v). Experimental results indicated aqueous ammonia can absorb CO2 in a hollow fiber membrane contactor over a wide range of experimental conditions. The value of KG ranged from 1.06 x 10(-4) to 2.89 x 10(-4) m/s. The impacts of operating parameters including CO2 partial pressure, liquid flow rate, ammonia concentration and inletCO2 solution loading were evaluated. The parametric impacts are similar to those of traditional amine-based absorption processes. Although the reactivity of aqueous ammonia is moderately lower than MEA, the K(G)a(v) value of aqueous ammonia is the same order of magnitude as that of MEA under the same operating conditions. As the liquid flow rate increases aqueous ammonia can achieve a performance comparable to MEA solvent. Long-term stability tests showed the absorption performance of aqueous ammonia remained constant in the first hour and then gradually decreased over time. Precipitation of ammonium salts was observed on the membrane surface of the shell side, which caused membrane fouling and may facilitate membrane wetting.

Membrane gas solvent contactors have the potential to revolutionize carbon capture, because the technology combines the advantages of both membrane and solvent technologies. Here, an asymmetric composite poly dimethylsiloxane (PDMS) on porous polysulfone membrane contactor was studied for the desorption of CO2 from loaded 30 wt% monoethanolamine (MEA) solution. Importantly, this study investigated the performance of the contactor at temperatures where the MEA solution entered the contactor as a liquid and as a vapor. It was found that the PDMS contactor CO2 flux was comparable to other reported membrane contactors when the MEA solution was in the solvent phase, but when the feed was vaporized the CO2 flux increased by an order of magnitude. Similarly, the overall mass transfer coefficient had the same behavior, in that an order of magnitude increase was obtained when the MEA solution was above the boiling temperature. The CO2 permeability through the non-porous PDMS layer was calculated based on mass transfer correlations and the temperature trend was comparable to literature. This indicated that CO2 transport through the PDMS layer was the same for the range of temperature and phase conditions studied, and that the mechanism was based on CO2 transporting in the gas phase. Significantly high water fluxes were observed through the PDMS membrane, two orders of magnitude greater than CO2, which was comparable with other non-porous contactors. However, at 110 degrees C, the H2O/CO2 flux selectivity decreased to 14, indicative of the higher CO2 flux at that temperature because of the vapor feed. (C) 2016 Elsevier Ltd. All rights reserved.

Membrane gas solvent contactors show potential for carbon capture, because it incorporates the advantage of both solvent and membrane technology. Here, three thin film composite membrane contactors are trialed for the absorption of CO2 into monoethanolamine (MEA) solvent. These are prepared from coating dense poly (1-trimethylsilyl-1-propyne) (PTMSP), a Polymer of Intrinsic Microporosity (PIM-1) and Teflon AF1600 on a porous PP support. It was found that after 1 h of operation, the PTMSP and PIM-1 membrane contactors provided the highest overall mass transfer coefficient, while Teflon AF1600 performance was lower. Comparison of the CO2 permeability through the membrane based on mass transfer resistance calculations showed that both PTMSP and PIM-1 had significantly hindered CO2 permeance compared to that expected from gas permeability measurements. This was due to the presence of water and MEA sorbed within the non-porous layer hindering the migration of CO2 through both membranes. Importantly, for both PTMSP and PIM-1 membranes water migrated over time from the dense layer into the porous support and wetted the pores. The Teflon AF1600 dense layer was resistant to water and MEA sorption and hence the permeation of CO2 through this layer was comparable to that expected from gas permeability measurements. Equally important, after 10 h of operation no change in overall mass transfer coefficient was observed indicating that Teflon AF1600 was able to prevent water from wetting the porous PP support. Hence, for thin film composite membrane contactors to be effective for CO2 separation, the dense layer must have a high CO2 permeability as well as be resistant to water sorption. (C) 2015 Elsevier Ltd. All rights reserved.

Membrane gas solvent contactors are a hybrid approach that shows potential to be more efficient for carbon dioxide capture than traditional packed columns. Here, three non-porous composite membrane contactors are trialed for desorption of CO2 from loaded Monoethanolamine (MEA) at temperatures 70 degrees C and above. These are non-porous poly (1-trimethylsilyl-1-propyne) (PTMSP), Polymer of Intrinsic Microporosity (NM-1) and Teflon AF1600, all on a porous PP support. The CO2 regeneration flux was shown to increase with temperature because of increasing driving force across the membrane. Similarly, the CO2 flux increased with solvent Reynolds number because of increasing turbulence in the solvent boundary layer. The overall mass transfer coefficient for the three membrane contactors were calculated and demonstrated that desorption was a mass transfer limiting process, with over 90% of the resistance corresponding to the solvent boundary layer. The water vapor fluxes through the non-porous membrane contactors were also measured and highlighted that water permeation was greater than CO2 for all three membrane contactor systems. (C) 2015 Elsevier B.V. All rights reserved.

Three one credit hour sequential courses are described as a tool for delivering and assessing learning outcomes in the CEAB mandated attributes of Life-Long Learning and Professionalism as an augmentation to existing work study programs at the University of Regina. The development of these courses through the Masters of Engineering program, allowing a smaller scale trial before full scale implementation at the undergraduate level is described. The future development and potential expansion of this course offering as a professional development offering to practicing engineers is also presented.

Three one credit hour sequential coursesare described as a tool for delivering and assessinglearning outcomes in the CEAB mandated attributes ofLife-Long Learning and Professionalism as anaugmentation to existing work study programs at theUniversity of Regina. The development of these coursesthrough the Masters of Engineering program, allowing asmaller scale trial before full scale implementation at theundergraduate level is described. The future developmentand potential expansion of this course offering as aprofessional development offering to practicing engineersis also presented.

Vinylbenzylchloride (VBC) and divinylbenzene (DVB) were used to prepare a new adsorbent for CO2 capture by the high internal phase emulsion technique. Effects of surfactant, water fraction, monomer ratio, and porogen type on the properties of the adsorbent were studied to select a suitable condition for preparation. Optimal properties were obtained from 90 vol% water fraction, 20 wt% of three component surfactants, 65/35 volume ratio of DVB/VBC and chloroethylbenzene porogen. The new material had a surface area of 150 m2/g with an adsorption capacity of 0.106 mmol/g.

Poly(vinylbenzylchloride/divinylbenzene); by high internal phase emulsion (poly(VBC/DVB)HIPE) was functionalized with diamines (ethylenediamine, piperazine, aminopiperidine, and imidazole) to improve carbon dioxide adsorption capacity. The amine group in the poly(VBC/DVB)HIPE was confirmed and quantified by Fourier transform infrared spectroscopy and elemental analysis. The surface area, pore size, and pore volume of the materials, after being functionalized with amines, were reduced. The order of the amine loading in the materials was ethylenediamine > piperazine > aminopiperidine > imidazole. The CO2 adsorption capacities were 2.18, 0.83, 0.66, and 0.39 mmol/g.m2.mol amine for the polyHIPE materials of ethylenediamine, piperazine, aminopiperidine, and imidazole, respectively.

This paper is Part 7 of the post-combustion carbon capture technology Review Series. It reviews recent progress and developments in hollow fibre membrane contactor research for CO2 capture. Hollow fiber membrane contactors have been studied for CO2 capture from a gas stream since 1985. In recent years, this technology has been considered a promising alternative to conventional absorption technologies, since it offers higher absorption efficiency and avoids common operating problems found in traditional packed columns. In this review, research development focused on CO2 capture using hollow fiber membrane contactors - including membrane module design, mass transfer principles, membrane wetting, simulation and modeling, and solvent regeneration - is presented. Additionally, current significant pilot-scale applications of this technology are discussed and recommendations for future work are presented.

An excellent porous material was prepared from vinylbenzyl chloride (VBC) and divinylbenzene (DVB) via high internal phase emulsion (HIPE) technique and introduced with heterocyclic amines (piperazine or PZ, hydroxyethylpiperazine or HEP and aminoethylpiperazine or AEP) by post-functionalization for using as adsorbents in CO2 capture applications. The reaction between the amine functional group and adsorbent was confirmed by Fourier transform infrared spectroscopy. The disappearance of C-Cl bonding at 1,265cm-1 and 710 cm-1 and the presence of N-H bonds at 3,400 cm-1 and 1,670 cm-1 were observed. The influence of the amine structure on the surface area and the conversion reaction of polyHIPE were investigated by surface area analysis and elemental analysis. In the CO2 adsorption step, the feed gas concentration was 4 vol% of CO2/N2 with a flow rate of 5 mL/min, and was carried out at 298 K. The CO2 concentration was continuously determined by gas chromatography. The dynamic adsorption capacity of PZ-HIPE, HEP-HIPE, and AEP-HIPE were 0.112, 0.057, and 0.074 mmol CO2/mmol amine compound.

Polyvinylbenzyl chloride-divinylbenzene was prepared using the high internal phase emulsion (HIPE) technique and modified with ethylenediamine and triethylenetetramine. All adsorbents were characterized witha fourier transform infrared spectrometer, elemental analyzer, and surface area analyzer. These adsorbents were to be used as adsorbents for a CO2 adsorption study. The experiments were carried out at room temperature and atmospheric pressure using dry 4% CO2/N2 feed gas. The adsorption capacity results showed that the triethylenetetramine adsorbent (0.3283 mmolCO2/g-adsorbent) had a greater adsorption capacity than the ethylenediamine adsorbent (0.3172 mmol CO2/g- adsorbent).

Polytetrafluoroethylene (PTFE) plasma sputtering of polypropylene (PP) membranes allows the formation of an ultrathin fluorinated hydrophobic surface that retains the microporous surface structure of the underlying membrane. The absorption results presented in this paper show that the novel PP membrane material performs well for the separation of CO2 from other gases, using an amine-based solvent. Hollow fiber membrane experiments show that the plasma-treated hollow fiber membrane has a superior CO2 mass transfer rate to untreated PP when coupled with monoethanolamine solvent flowing through the fiber lumen for at least 45 h of absorption time. The CO2 mass-transfer rate through the treated hollow fiber membrane is also comparable with that of other researchers who have absorbed CO2 into amine solvents using PTFE hollow fibers and higher than that measured using packed column technology with structured packing and amine solvents.

Membrane contactor based CO2 stripping experiments were conducted using loaded CO2 monoethanolamine (MEA) solution as an absorbent while N2 gas was used as a stripping gas. A membrane module made from stainless steel was developed to test a variety of membrane cartridges. Polytetrafluoroethylene (PTFE) hollow fiber membranes were used in this work to test the desorption performance and membrane stability in gas stripping membrane contactor. The effect of the operating variables investigated included gas and liquid velocities, MEA concentration, and temperature. The experimental results showed that the stripping gas velocity had a minor effect on the CO2 desorption flux and mass transfer coefficients while the increase in the liquid velocity, operating temperature, and solution concentration could enhance CO2 desorption flux in the gas stripping membrane contactor. However, the CO2 desorption flux started to decrease at 5.0 kmol m−3 MEA solution. A high membrane porosity showed a superior desorption performance, but the long term performance deteriorated due to the membrane wetting.

A membrane contactor based desorption process was developed to strip carbon dioxide (CO2) from loaded monoethalamine (MEA) solution. Nitrogen (N-2) gas was used as a stripping gas instead of steam in a conventional column. Polytetrafluoroethylene (PTFE) hollow fiber membranes were used to test the desorption performance. The liquid solution was fed in the lumen while the stripping gas was fed through the shell side. The stripping gas, liquid velocities, operating temperature, and MEA concentration were all investigated for their effect on CO2 desorption flux. It was found that the CO2 desorption flux was relatively constant with an increase stripping gas velocity while the liquid velocity, operating temperature, and solution concentration could enhance CO2 desorption flux in the membrane contactor based desorption process. However, an increase the solution concentration of 5 kmol m(-3) resulted in a decrease in the CO2 desorption flux due to the effect of viscosity. (C) 2011 Published by Elsevier Ltd.

Post-combustion CO2 capture and storage (CCS) presents a promising strategy to capture, compress, transport and store CO2 from a high volume–low pressure flue gas stream emitted from a fossil fuel-fired power plant. This work undertakes the simulation of CO2 capture and compression integration into an 800 MWe supercritical coal-fired power plant using chemical process simulators. The focus is not only on the simulation of full load of flue gas stream into the CO2 capture and compression, but also, on the impact of a partial load. The result reveals that the energy penalty of a low capture efficiency, for example, at 50% capture efficiency with 10% flue gas load is higher than for 90% flue gas load at the equivalent capture efficiency by about 440 kWhe/tonne CO2. The study also addresses the effect of CO2 capture performance by different coal ranks. It is found that lignite pulverized coal (PC)-fired power plant has a higher energy requirement than subbituminous and bituminous PC-fired power plants by 40.1 and 98.6 MWe, respectively. In addition to the investigation of energy requirement, other significant parameters including energy penalty, plant efficiency, amine flow rate and extracted steam flow rate, are also presented. The study reveals that operating at partial load, for example at half load with 90% CO2 capture efficiency, as compared with full load, reduces the energy penalty, plant efficiency drop, amine flow rate and extracted steam flow rate by 9.9%, 24.4%, 50.0% and 49.9%, respectively. In addition, the effect of steam extracted from different locations from a series of steam turbine with the objective to achieve the lowest possible energy penalty is evaluated. The simulation shows that a low extracted steam pressure from a series of steam turbines, for example at 300 kPa, minimizes the energy penalty by up to 25.3%.

A mathematical model was developed to simulate the concentration profile in a gas absorption membrane (GAM) system. Carbon dioxide (CO2) absorption into an aqueous solution of monoethanolamine (MEA) was investigated in the GAM system. Three GAM modules were potted with polytetrafluoroethylene (PTFE) membranes and connected in series to measure CO2 concentration and CO2 loading profiles along the length of the GAM system. The model predictions for CO2 concentration and CO2 loading profiles along the length of GAM column were in excellent agreement with the experimental results. The average absolute deviation between the model and experimental results was 1.49%. The Wilson plot method was used to determine the membrane resistance, which was compared with a theoretical membrane resistance. It was found that the membrane mass transfer resistance calculated using the Wilson plot method could predict the CO2 concentration profile with a higher accuracy than the theoretical method. Partial membrane wetting was modeled to investigate the effect of membrane mass transfer resistance on the absorption performance and the overall mass transfer coefficient. The results showed that an acceptable membrane wetting for CO2 absorption in MEA solutions in GAM systems was 40%. A higher lean solution temperature increased the membrane wetting in the GAM system. The membrane mass transfer resistance in completely liquid-filled membrane pores accounted for 92% of overall mass transfer resistance.

Energy is the most critical factor for the growth of a nation's economy. However, its use has a major impact on the environment especially by discharging air pollutants into the atmosphere. In addition, energy production from fossil fuel, the world's most important fuel, is recently known to be the key contributor of CO2 (a major greenhouse gas) resulting in global warming problems. This article is an extension of our earlier research work to demonstrate how cogeneration concepts can be used to reduce production costs and simultaneously produce electricity, steam as well as industrial gases such as CO2. With cogeneration, there is very little air pollution discharged into the atmosphere. We discuss a case study of an enhanced oil recovery (EOR) application.

Liquid flow distribution in a square column was analyzed to evaluate the contact between liquid and gas phases in an absorption column, and to compare the results from a conventional cylindrical column. The square column was 12-inches wide by 12-inches deep by 40-inches tall. It was constructed with glass walls so that the flow pattern could be observed. The liquid distributor was designed with a pattern that would deliver the flow evenly in a set pattern over the packing with a drip per area ratio of 321/ft(2) (2.23/inch(2)).Experiments were conducted using both random and structured packing. A total packing volume of 3ft(3) was used in each study. One-inch Pall Rings were used for the random packing study. For the structured packing tests, we designed and developed an innovative packing for the ITC pilot plant. Three packing bricks were used in the column. The testing of the structured packing was done using two different packed brick orientations; one with all of the bricks in the same flow direction, the other with the middle brick rotated 90 degrees from the orientation of the top and bottom bricks.A monoethanolamine ( MEA) solution concentration of 3.0 molar was used in the experiments. The liquid distribution tests were done at one flow rates. Since the viscosity of the MEA solution was affected by the carbon dioxide (CO(2)) solution loading, experiments were also conducted to evaluate the effects of CO(2) loading on the liquid hold-up.Our goal is to develop a cost effective structure packing that performs at a level that is comparable to commercially available packing, but with lower manufacturing and installation cost. (C) 2008 Elsevier Ltd. All rights reserved.

Hollow fiber membrane contactors have been studied extensively in the last decade. Gas absorption membrane (GAM) contactors are a developing technology that overcome the disadvantage of conventional equipment. Three different membranes, including polytetrafluoroethylene (PTFE), polypropylene (PP), and polyvinylidene fluoride (PVDF), were used to test the performance of a GAM system in both physical and chemical absorption studies. In the physical absorption experiments, pure CO2 and de-ionized water were used in the GAM system. A Wilson plot was used to determine the membrane resistance in this work. From the results, the PVDF membrane had a higher CO2 flux than PP membranes and the highest membrane resistance. In the chemical absorption experiments, a simulated flue gas stream (15% CO2 and 85% air) was treated with monoethanolamine (MEA) solutions. Experimental results showed that the CO2 absorption performance can be ranked as PTFE>PVDF>PP. While the PTFE membrane had the best performance in the GAM system, the PVDF membrane is an alternative membrane that could be used. The stability of PTFE and PVDF membranes was tested continuously over 60h of operation. The PTFE membranes maintained their absorption performance, while the PVDF membranes did not maintain their absorption performance over the operating time.