CO2 capture

The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrasonic-assisted method. The adsorbent was calcined at 200-500 °C and its adsorption capacity was measured. The ultrasonic-assisted synthesis generated well-dispersed of BaO on Fe2O3 by giving none of the BaO peaks were observed through the XRD pattern. The most efficient adsorbent of BaO/Fe2O3200 was calcined at 200 °C with adsorption capacity for physisorption and chemisorption of 5.01 and 88.81 mg/g respectively. Besides other carbonate species, it was believed the presence of the hydroxyl group could enhance the sorption by forming bicarbonate upon CO2 chemisorption. It is also possessed a lower desorption range compared to BaO and Fe2O3 alone. The experimental CO2 adsorption isotherm at 25 °C fit better with the Freundlich isotherm model. It implies a favorable adsorption process with multilayer adsorption occurs onto the heterogeneous surface.

The limitation of fresh water and the exorbitant cost of land to grow such plants, algae are the most optimum organisms for CO 2 bio-sequestration and also microalgae cultures avail many characteristics that make them an arguable option for higher productivities as compared to higher plants. The aim of this study was the sequestrate CO 2 by Spirulina platensis and Chlorella vulgaris under the different levels of salinity and CO 2. The highest growth rate obtained during the first 4 days and higher biomass concentration at CO 2 concentration from0.03% to 10% respectively. The significant (p<0.05) biomass productivity, growth rate and CO 2 sequestration rate under different level of CO 2 and EC between Spirulina platensis and Chlorella vulgaris were detected. The ultimate CO 2 sequestration rate of Spirulina platensis and Chlorella vulgaris were 0.49 and 0.152 g/L/d in natural water respectively, although in artificial sea water 0.419 and 0.097 g/L/d were recorded at 10% CO 2 concentrations respectively.

The extensive amount of available information on global warming suggests that this issue has become prevalent worldwide. Majority of countries have issued laws and policies in response to this concern by requiring their industrial sectors to reduce greenhouse gas emissions, such as CO 2. Thus, introducing new and more effective treatment methods, such as biological techniques, is crucial to control the emission of greenhouse gases. Many studies have demonstrated CO 2 fixation using photo-bioreactors and raceway ponds, but a comprehensive review is yet to be published on biological CO 2 fixation. A comprehensive review of CO 2 fixation through biological process is presented in this paper as biological processes are ideal to control both organic and inorganic pollutants. This process can also cover the classification of methods, functional mechanisms, designs, and their operational parameters, which are crucial for efficient CO 2 fixation. This review also suggests the bio-trickling filter process as an appropriate approach in CO 2 fixation to assist in creating a pollution-free environment. Finally, this paper introduces optimum designs, growth rate models, and CO 2 fixation of microalgae, functions, and operations in biological CO 2 fixation.

This study presents a rate-based model of an absorber packed column for simultaneous absorptions of acid gases into methyldiethanolamine (MDEA) aqueous solution.  The model is in good agreement with experimental data.  The parametric study showed that the concentration of acid gases in the sweet gas stream increases by decrease in the specific surface area of packing.  The peak of selectivity factor decreases with the increase in the mole ratio of CO2/H2S in the gas feed along the packed column.  The sensitivity analysis reveals that selecting the accurate correlations of the gas-side mass transfer coefficient and specific surface area is vital.

Dalam beberapa dekade terakhir ini, isu pemanasan global (global warming) menjadi sebuah topik yang hangat untuk dibicarakan. Pemanasan global adalah peristiwa naiknya suhu rata-rata permukaan dan lapisan atmosfer bumi yang disebabkan oleh gas rumah kaca. Pengertian gas rumah kaca itu sendiri adalah gas-gas yang berada di lapisan atmosfer yang menyebabkan terjadinya efek rumah kaca misalnya CO2, CH4, SF4, dan sebagainya. Radiasi sinar matahari yang menembus lapisan atmosfer bumi tidak dapat dipantulkan kembali ke angkasa akibat adanya gas-gas rumah kaca tersebut. Sebagai akibatnya, pantulan radiasi sinar matahari terperangkap di lapisan atmosfer dan akhirnya menyebabkan suhu rata-rata permukaan dan lapisan atmosfer meningkat.

This PhD dissertation summarizes Dr Wang's work on packing mass transfer studies, which can be applied to CO2 absorption as well as other distillation and absorption processes. The three key mass transfer parameters: effective mass transfer area (ae), liquid film mass transfer coefficient (kL), and gas film mass transfer coefficient (kG) were measured consistently in a pilot-scale packed column. The database contains eleven widely used structured packings and three random packings. The effects of operating conditions and packing geometries on mass transfer were explored.

Three global dimensionless mass transfer models were developed, and can be used  to predict the mass transfer properties for most structured packings. A new concept, Mixing Point Density, was introduced to account for effect of the packing geometry on mass transfer. Mixing Point Density represents the frequency at which liquid film is refreshed and gas is mixed.

An economic analysis of the absorber was conducted for a 250 MW coal-fired power plant, with the application of the developed mass transfer models in this work. The optimum operating condition is between 50 to 80 % of flooding, and the optimum design is to use packing with 200 to 250 m^2/m^3 surface area and high corrugation angle (60 to 70 degree). The minimum total cost ranges from $4.04 to $5.83 per tonne CO2 removed with 8 m PZ.

This research covered the rate-based process simulation (ProMax® 4.0) and techno-economic analysis of carbon dioxide (CO2) capture from a 1.2 million metric tonne per annum cement plant using aqueous 2 kmol/m3 AMP-1 kmol/m3 PZ-2 kmol/m3 MEA blend. The waste gas composition for this study was provided by a cement plant from Quebec, Canada. The effect of amine type, energy penalty, and CO2 capture efficiency (50% to 90%) on the capture costs (US$/tonne CO2 and US$/tonne cement) were investigated. Sensitivity analysis on the impact of CO2 capture plant, carbon tax (US$ 20 to US$ 40 per tonne of CO2), CO2 sales price (US$ 10 to US$ 40 per tonne of CO2), energy penalty and CO2 capture efficiency on the cement price was also investigated. Results revealed that at 90% CO2 capture efficiency, the capture costs of AMP-PZ-MEA (US$77.34/tonne CO2 and US$44.94/tonne cement) is lower than that of MEA (US$93.23/tonne CO2 and US$54.17/tonne cement). Results also revealed that the total equipment cost and capital expenditure (CAPEX) of MEA system (US$ 29.76 million and US$ 147.12 million) higher than that of AMP-PZ-MEA blend (US$ 23.39 million and US$ 127.59 million).

Cash flow analysis showed that without adding a CO2 capture unit to a cement plant, carbon tax increased the cement price up to 22.9%. However, a combination of the high carbon tax, high CO2 sales price, low energy penalty, and high capture efficiency increased the cement price up to 1.2% for the MEA system but reduced the cement price up to 5% for the AMP-PZ-MEA system. This comprehensive study shows that a cost-effective and energy-efficient amine blend, energy penalty, CO2 capture efficiency, carbon tax, and CO2 sales prices are all integral towards reducing the cement price while significantly reducing the CO2 emissions.

A B S T R A C T Bioenergy with Carbon Capture and Storage (BECCS) is recognised as a key technology to mitigate CO 2 emissions and achieve stringent climate targets due to its potential for negative emissions. However, the cost for its deployment is expected to be higher than for fossil-based power plants with CCS. To help in the transition to fully replace fossil fuels, co-firing of coal and biomass provide a less expensive means. Therefore, this work examines the co-firing at various levels in a pulverised supercritical power plant with post-combustion CO 2 capture, using a fully integrated model developed in Aspen Plus. Co-firing offers flexibility in terms of the biomass resources needed. This work also investigates flexibility within operation. As a result, the performance of the power plant at various part-loads (40%, 60% and 80%) is studied and compared to the baseline at 100%, using a constant fuel flowrate. It was found that the net power output and net efficiency decrease when the biomass fraction increases for constant heat input and constant fuel flow rate cases. At constant heat input, more fuel is required as the biomass fraction is increased; whilst at constant fuel input, derating occurs, e.g. 30% derating of the power output capacity at firing 100% biomass compared to 100% coal. Co-firing of coal and biomass resulted in substantial power derating at each part-load operation.

• A new process for CO 2 capture and water desalination has been developed. • It is based on a Modified Solvay process without using ammonia. • It is more efficient in CO 2 capture and Sodium reduction than the Solvay process. • The new process can achieve 99% CO 2 capture efficiency and 35% Sodium removal. • The energy requirements are much lower than that of the Solvay process. a b s t r a c t The present work evaluates a new process for the capture of CO 2 and the reduction of water salinity. It is based on the Solvay process without the use of ammonia and involves the reaction of CO 2 with saline water such as reject brine in the presence of calcium hydroxide. The effects of operating parameters such as reaction temperature, water pH and reaction stoichiometry on CO 2 capture efficiency and sodium removal were examined for both traditional and modified Solvay process. The optimum conditions for maximum CO 2 capture efficiency and sodium removal were determined using response surface methodology and were found to be at temperature of 20 °C and a pH of greater than 10 for both processes. At the optimum conditions, CO 2 capture of 86% and 99% and sodium removal of 29% and 35% were achieved for the traditional Solvay and the Modified process, respectively. The water pH was found to be a key parameter in the effectiveness of the reaction process; higher pH leads to better process performance in both CO 2 capture efficiency and sodium removal. The experimental results clearly illustrated that the Modified Solvay process is superior in terms of CO 2 capture efficiency, sodium removal and energy consumption.

Over the past 10 years, there has been a surge of interest in anion exchange membrane fuel cells (AEMFCs) as a potentially lower cost alternative to proton exchange membrane fuel cells (PEMFCs). Recent work has shown that AEMFCs achieved nearly identical performance to state-of-the-art PEMFCs; however, much of that data has been collected while feeding CO2-free air or pure oxygen to the cathode. Usually, removing CO2 from the oxidant is done in order to avoid the detrimental effect of CO2 on AEMFC performance, due to carbonation where CO2 reacts with the OH- anions, forming HCO3- and CO32-. In spite of the crucial importance of this topic for the future development and commercialization of AEMFCs, unfortunately there have been very few investigations devoted to this phenomenon and its effects. Much of the data available in the literature is widely spread out and there currently does not exist a resource that researchers in the field, or those looking to enter the field, can use as a reference text that explains the complex influence of CO2 and HCO3-/CO32- on all aspects of AEMFC performance. The purpose of this review is to summarize the experimental and theoretical work that has been reported in the literature for the effect of ambient CO2 on AEMFCs. This systematic review intends to create a single comprehensive account of what is known regarding how CO2 behaves in AEMFCs to date, as well as identify the most important areas for future work in this field.

In recent years the climate change became a global concern due to the increasing of the earth’s surface temperature. This phenomenon was exacerbated by the expansion of industrial activities due to the increasing emissions of the greenhouse gas (mainly CO2). Many efforts were conducted to capture CO2 from the industrial process streams. Membrane gas absorption system (MGAS) was proposed as an alternative technique to overcome disadvantages of the conventional CO2 absorption processes. However, there are still many challenges in order to commercialize MGAS such as membrane surface stability, absorbent liquid efficiency and compatibility between absorbent liquid and membrane material. In order to solve this problem, a porous superhydrophobic layer of low density polyethylene (LDPE) had been coated on the outer surface of the polypropylene (PP) and polyvinylidene fluoride (PVDF) hollow fiber membrane via solvent non-solvent coating method. Parameters to prepare superhydrophobic flat surface (non-solvent type, non-solvent content in coating solution and polymer concentration) had been studied and optimized. It was observed that non-solvent like ethanol did produce polymeric surface with higher water contact angle (WCA) compared to methyl ethyl ketone used as non-solvent additives. The increasing of ethanol content in the coating solution up to 50% (v/v) led to the increased of WCA from 110±2.8o to 160±1.4o. The hydrophobicity of the coated layers were analysed in terms of surface roughness, physical structure and water contact angle. It was found that the WCA of the coated PP and PVDF hollow fiber membranes surfaces prepared via direct dip coating were less than the flat surface. Indirect method was proposed and the maximum WCA of modified PP and PVDF membranes were 161±2.3o and 152±3.2o, respectively. A continuous MGAS inhouse-built was designed to evaluate the performance of modified membranes in term of CO2 removal from gas stream of 20% (v/v) CO2 balanced with N2. The operating parameters (liquid velocity, gas velocity and packing density of the membrane module) and other effects on the CO2 removal were studied. The CO2 absorption performance was investigated for different absorbent liquids namely piperazine (PZ), monoethanolamine (MEA), diethanolamine (DEA) and their blends. PZ exhibited higher absorption efficiency than other absorbents. In terms of the membrane’s compatibility with PZ, PVDF membrane was found to have high surface stability compared to the PP membrane. In addition, it was observed that the activated MEA had CO2 absorption efficiency higher than activated DEA at the same concentrations and operating conditions. The mass transfer resistance through the membrane module was determined via Wilson plot method. It was observed that the liquid mass transfer resistance was the controlling step in all amine solutions. Moreover, the overall mass transfer coefficient was increased with the increasing of the activator concentration in the amine blends.

Monodispersed zeolitic imidazolate frameworks (ZIFs) were prepared with a simple method using dimethylsulfoxide (DMSO) as solvent. This method yields ZIF-8 nanoparticles with a narrow particle size distribution of 90–110 nm and the dispersion is highly stable against agglomeration. These particles have larger nanosized porosity and enhanced CO 2 adsorption capability compared to ZIF-8 prepared with different solvents such as methanol or N, N-dimethyl formamide. Their uniform size and surface chemistry also lead to superior performance in the Knoevenagel condensation reactions. The ZIF-8 nanoparticles possess high thermal stability up to 550 • C and the preparation steps are easy for scaling up which are favorable for industrial applications.

The density and viscosity of aqueous mixtures of glycerol and N-Methyldiethanolamine (MDEA), glycerol and Monoethanolamine (MEA), glycerol and Piperazine (PZ) as well as glycerol and ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) were determined in this study. It was found that the density and viscosity of the mixtures increased with increasing glycerol concentration. The correlations of density and viscosity of the mixtures were determined as a function of the concentration of glycerol and temperature. For density correlation, the empirical linear equation used in this work showed excellent accuracy with 0.62% as the highest percentage deviation for all the mixtures involved. While for the viscosity correlation, there was a good fit between the mixtures and the extended Arrhenius equation with 9.91% as the highest percentage deviation from the experimental viscosity data.

Fossil fuels are projected to serve as the major source of energy worldwide in the coming decades. Emissions to the atmosphere of green house gases such as CO2 produced by the consumption of energy derived from fossil fuels are now comparable to the natural carbon cycle. Such emissions are already beginning to exert an observable influence on climate
change, perturbing natural climate stability. Carbon sequestration has been proposed to gradually reduce and eventually eliminate anthropogenic emissions of carbon dioxide into the atmosphere. The success of sequestration depends on the identification and manipulation of appropriate storage sites where CO2 can be sequestrated over long periods of time.
Deep saline aquifers are the preferred storage sites because of their potential for secure sequestration over long periods of time as well as their abundance and large capacity. The
primary mechanism for long term sequestration in saline aquifers is solubility trapping associated with the dissolution of CO2 into brine. The solution of saline water and dissolved
CO2 is negatively buoyant within the subsurface environment. The positively buoyant free CO2 is thus trapped and loses its ability to escape from the aquifer. The key aspect of solubility
trapping is gravitational convection associated with the unstable density stratication of dissolved CO2. The rate of mixing of free CO2 with brine is enhanced significantly as
a result of gravitational convection compared with the extremely slow process of diffusion limited mixing. The strength of convection depends on solubility, which is a function of
temperature and pressure and brine salinity. Dissolution of CO2 into brine leads further to the formation of carbonic acid that provides carbonate ions needed for the formation
of mineral precipitates. This process of mineral trapping of CO2 is considered to be the most permanent form of sequestration. The objective of the current study is to provide a perspective on the progress made thus far towards the modeling of the solubility of CO2 in brine and the dependence of pH on the saturated mole fraction as a function of pressure, temperature and salinity. The study is an attempt to facilitate the development of an integrated model for the prediction of the amount of CO2 that can be safely sequestered in saline aquifers.

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). Because of many unique features, DESs can be a versatile alternative to ionic liquids and traditional solvents. In this work, DESs were prepared namely allyltriphenylphospho-nium bromide-diethylene glycol (ATPPB-DEG) and allyltriphenylphosphonium bromide-triethylene gly-col (ATPPB-TEG) into three mole ratios 1:4, 1:10, and 1:16 salt to HBDs. The thermal stability was comprehensively analysed under the temperature range of (30–800) °C. The conductivity and pH values were determined within the temperature range of 293.15 K–343.15 K. The results revealed that the amount and type of HBDs have an effect on these properties. Moreover, the effect of temperature was studied on these properties. As the temperature increases, the conductivity values increase while the pH values decrease. Finally, a new empirical equation was applied to correlate the experimental conductivity and pH data. It was found that this equation is powerful and reliable to correlate these properties of DESs.

The equilibrium adsorption isotherms of carbon dioxide on a commercial granular activated carbon (GAC) and an ammonia-modified GAC (OXA-GAC) were measured using a static volumetric method. CO2 adsorption measurements were performed at three different tem-peratures (303, 318, and 333 K), and pressures up to 1 atm. The obtained equilibrium data were fitted to the Freundlich, Sips, and Toth isotherms using a semi-empirical approach to differentiate the contributions of physical and chemical adsorption to the total CO2 uptake.The isotherm parameters were determined independently for each mechanism by non-linear regression. To evaluate the adequacy of the fit of the isotherm models, two different error functions (i.e., the average relative error and the nonlinear regression coefficient) were calculated. The Toth semi-empirical equilibrium model provided the best fit to the experimental data, with average relative errors of less than 3% observed at all temperatures.The isosteric heats of CO2 adsorption onto the ammonia-modified adsorbent and onto theuntreated adsorbent were determined using the Clausius–Clapeyron equation. The load-ing dependence of the isosteric enthalpy of CO2 adsorption over the OXA-GAC reflected an energetic heterogeneity of the adsorbent surface. The initial isosteric heats of adsorption of 70.5 kJ mol−1 and 25.5 kJ mol−1correspond to the adsorption of CO2on the modified and untreated adsorbents, respectively, and these values were in excellent agreement with the zero-coverage heats of adsorption obtained using the temperature-dependent parameters of the proposed model.

Mineral CO2 sequestration is a promising process for the reduction of carbon dioxide emissions to the
atmosphere. In this paper, alkaline calcium-rich dust particles collected from bag filters of electric arc
furnaces (EAF) for steel making were utilized as a viable raw material for mineral CO2 sequestration. The
dust particles were pre-treated through hydration, drying and screening. The pre-treated particles were
then subjected to direct gasesolid carbonation reaction in a fluidized-bed reactor. The carbonated
products were characterized to determine the overall sequestration capacity and the mineralogical
structures. Leaching tests were also performed to measure the extracted minerals from the carbonated
dust and evaluate the carbonation process on dust stabilization. The experimental results indicated that
CO2 could be sequestered using the pre-treated bag house dust. The maximum sequestration of CO2 was
0.657 kg/kg of dust, based on the total calcium content. The highest degree of carbonation achieved was
42.5% and the carbonation efficiency was 69% at room temperature.

The application of carbon capture and storage (CCS) and carbon neutral techniques should be adopted to reduce the CO 2 emissions from power generation systems. These environmental concerns have renewed interest towards the use of biomass as an alternative to fossil fuels. This study investigates the comparative potential of different power generation systems, including NGCC with and without exhaust gas recirculation (EGR), pulverised su-percritical coal and biomass fired power plants for constant heat input and constant fuel flowrate cases. The modelling of all the power plant cases is realized in Aspen Plus at the gross power output of 800 MW e and integrated with a MEA-based CO 2 capture plant and a CO 2 compression unit. Full-scale detailed modelling of integrated power plant with a CO 2 capture and compression system for biomass fuel for two different cases is reported and compared with the conventional ones. The process performance, in terms of efficiency, emissions and potential losses for all the cases, is analysed. In conclusion, NGCC and NGCC with EGR integrated with CO 2 capture and compression results in higher net efficiency and least efficiency penalty reduction. Further, coal and biomass fired power plants integrated with CO 2 capture and compression results in higher specific CO 2 capture and the least specific losses per unit of the CO 2 captured. Furthermore, biomass with CO 2 capture and compression results in negative emissions.

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs).  In this work, six deep eutectic solvents (DESs) were prepared namely allyltriphenyl phosphonium bromide- diethylene glycol (ATPPB-DEG) and allyltriphenyl phosphonium bromide - triethylene glycol (ATPPB-TEG) using three molar ratios of 1:4, 1:10 and 1:16 salt to HBDs. The temperature range for experimental viscosity was from 293.15 to 343.15 K and that of the experimental surface tension was between 298.15 and343.15 K. The results disclosed that hydrogen bonding (H…Br)  in DESs has a great effect on the properties. Among all DESs with the same components, the DESs with the strong hydrogen bonding (H…Br)  in their structures had the higher viscosity and surface tension. Besides, by increasing the temperature and quantity of HBDs in DESs, both of these properties experienced a decrease decreasing  trend in the amount. It was found that the molecular weight of DESs with the same component has an effect on the properties. The higher molecular weight caused the higher viscosity and surface tension. Further, ATPPB-TEG DESs had the higher viscosity and lower surface tension than ATPPB-DEG DESs because of the higher alkyl chain in their structures. Several models and a new empirical equation were used to correlate the experimental viscosity data. It was found that there is a well agreement between theoretical and experimental values especially when the new empirical equation is used. In addition, the activation parameters for all DESs were calculated using the experimental viscosity data and application of Eyring’s absolute rate theory. The experimental surface tension was employed to predict the critical temperature and, surface entropy and internal surface energy of DESs. Finally, two empirical equations were used for relating the experimental surface tension to the experimental viscosity of DESs.

Synthesized iron oxide, α-Fe 2 O 3 used for CO 2 capturing was prepared by a simple mixing method and calcined at temperatures in a range of 350 – 850 °C. CO 2 adsorption isotherms at 25 °C and 1 atm found that the sample namely s450 that calcined at 450 °C gave the highest CO 2 adsorption activity with the adsorption capacity of 17.0 mg CO2 /g adsorbent. Monodentate carbonate, bidentate carbonate and bicarbonates formation were observed on s450 through the IR spectra. The basicity of s450 was identified by chemisorption of CO-TPD which contains weak, medium and strong basic sites with CO total adsorbed amount of 1.99 cm 3 /g. It was found that s450 calcined at 450 °C has certain crystallite peaks that abruptly increased through the XRD diffractogram. The texture properties of s450 generated high porosity and more uniform sphere shape particle size with high surface area (50.5 m 2 /g). Furthermore, it is composed of trimodal distribution for pore size distribution curve desirable for CO 2 adsorption. Abstrak Penjerapan CO 2 terhadap ferum oksida, α-Fe 2 O 3 yang disintesis melalui kaedah campuran ringkas dan dikalsin pada suhu 350-850 °C. Penjerapan isoterma CO 2 pada suhu bilik, 25 °C and 1 atm mendapati sampel s450 yang dikalsin pada suhu 450 °C menunjukkan aktiviti penjerapan CO 2 paling tinggi dengan keupayaan penjerapan sebanyak 17.0 mg CO2 /g penjerap. Spektrum IR telah membuktikan pembentukan spesis monodentat karbonat, bidentat karbonat dan bikarbonat pada s450. Sifat bes s450 yang dikenalpasti menggunakan jerapan kimia CO-TPD dimana jumlah CO yang dijerap oleh tapak bes lemah, sederhana dan kuat adalah 1.99 cm 3 /g. Difraktogram XRD pula menunjukkan terdapat beberapa puncak kekisi yang meningkat. Tekstur s450 pula mempunyai keporosan yang tinggi dan bentuk sfera yang lebih sekata serta luas permukaan yang tinggi (50.5 m 2 /g). Tambahan lagi, graf taburan saiz liang s450 juga terdiri daripada taburan jenis trimodal yang menjadi salah satu faktor penting dalam penjerapan CO 2. Kata kunci: penjerapan CO 2 , penjerapan, ferum oksida, penjerapan pepejal, keporosan

CO 2 is the primary gas and the best-known greenhouse gas (GHG) contributing to global warming. Non-renewable fossil fuel energies are the primary energy sources. Annually, 24 billion tons of CO 2 is produced by human activity, and especially fossil fuel combustion, thus, the primary source of CO 2 emission is fossil fuel including coal, oil, and natural gas which accounts for 65% (United States Environmental Protection Agency, 2014). The CO 2 level in the atmosphere has raisen from 310 ppm in 1958 to 413.71 ppm in 2021 (August 24) according to the latest reading reported by Scripps Institution of Oceanography (2021), and is rising faster and faster; that is why contemporary research has focused on ways to slow or stop this trend and globally, there has been a significant increase in interest in reducing CO 2 emissions in both

This study provides useful information on the existing interactions in an aqueous solution of deep eutectic solvents (DESs) by studying excess properties namely excess refractive index and excess logarithm viscosity at different concentrations and temperatures. In order to investigate the effects of DES mole fraction and temperature on the refractive index and viscosity of binary mixtures, the response surface methodology (RSM) was applied based on the mixed-level full factorial design. The analysis of variance (ANOVA) results revealed that although both DES mole fraction and temperature are significant, the DES mole fraction has more effect on these thermophysical properties. Results showed that as excess refractive index and excess logarithm viscosity values are positive over the whole composition range and maximum excess data were investigated at the water-reach region. Moreover, the effects of important factors influencing CO2 solubilities such as pressure, temperature, water content, and molecular weight of DES were determined using the Taguchi L18 method. A regression model was developed based on the Taguchi method for prediction of the prediction of CO2 solubility. The results disclosed that the pressure is the most significant factor influencing the CO2 fraction followed by the water content and molecular weight of DESs while the temperature had the lowest effect. The error evaluations indicated that the Taguchi model is an accurate model and had excellent performance in prediction of the CO2 solubility.

To understand critical problems associated with solid waste and its consequences for the environment, a laboratory experiment is presented on the synthesis of aluminum-based metal−organic framework (MOF) MIL-53(Al) from household waste (PET bottles and aluminum foil/can), for undergraduate students of chemistry. This work is designed to teach students the research methodology and basic understanding of MOFs and their application in carbon capture and storage (CCS). Students also learnt several instrumentation techniques such as UV−vis spec-troscopy, powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and gas sorption to characterize the physicochemical properties of MIL-53(Al). The facile production of MIL-53(Al) enabled the students to investigate its applicability in CO 2 sorption. The calculations of essential parameters such as CO 2 over N 2 selectivity and the use of statistical tools in data processing are also explained to the students. In the end, the instructor presented his/her feedback by evaluating the answer sheets (pre-and postlab work) and by demonstrating the overall lab work through a model presentation.

Exhaust Gas Recycle (EGR) is one of the technologies used to increase the CO 2 concentration in the gas turbine flue gas. This paper presents the results of an experimental campaign carried out at the Pilot-scale Advanced Capture Technology (PACT) facilities at the UK Carbon Capture and Storage Research Centre (UKCCSRC). A 100 kW e Turbec T100 PH microturbine was integrated with a post combustion CO 2 capture plant that has a CO 2 capture capacity of one ton per day. The impact of different CO 2 concentrations (representing a range of EGR ratios) on the post-combustion CO 2 capture process was experimentally evaluated using 30% (wt.%) Monoethanolamine (MEA) solvent. It was observed that the specific reboiler duty was reduced by around 7.1% per unit percentage increase in CO 2 concentration. Overall, it was seen that the higher the CO 2 concentration, the lower the specific reboiler duty at a fixed capture rate. Both rich and lean solvent loadings increased with increase in flue gas CO 2 concentration. Energy balance on the stripper has shown that steam generation rate and condenser duty increases with increase in CO 2 concentration. The experimental data was used to develop and validate the model for the Pilot-scale amine capture plant using Aspen HYSYS.

Carbon-based fuels contribute majorly towards global energy demand; however, it results in global warming. The increasing energy demand and climate change highlights the need to develop cost-effective carbon sequestration schemes. Amine-based CO2 scrubbing have been widely used for their high selectivity and production of pure CO2. However, a challenge in implementing amine-based technology is high energy consumption with a low capture ratio. The energy penalty can be reduced either by introducing new solvents, optimizing parameters, or through process modifications. Recently, ammonia has tempted attraction in place of amines. In this present work, a Radfrac model in Aspen Plus is developed involving heat integration and absorption enhancement to overcome the barriers. The heat integration is performed with a rich solvent split and absorption enhancement is done with split flow arrangement. Further, the model is evaluated at different split ratios by performing heat integration between different streams of the flowsheet. Moreover, the process configurations used in this system is compared with MEA based process modifications concerning energy reduction. A competitive reduction in regeneration duty was observed which was 36% less than the reference NH3 and 47% less than the MEA process. This evaluated modification will result in maximum efficiency, a maximum level of CO2 capture, and a reduction in the reboiler duty. The rich solvent split and split flow process reduced the reboiler duty by 15.8% and 32.8%, respectively. The split flow process also indicated an increase of 17.2% in rich loading to recover 90% CO2.

Deep eutectic solvents (DESs) are derived from the concomitant reaction of two or more salts i.e. between hydrogen bond acceptor (HBA) and hydrogen bond donors (HBD) components. In this work, DESs were prepared namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) and allyltriphenyl phosphonium bromide-triethylene glycol (ATPPB-TEG) into three molar ratios 1:4, 1:10, and 1:16 salt to HBDs. The carbon dioxide solubility in DESs at temperature of 303.15 K and pressure up to 2 MPa were determined and reported in terms of mole fraction, CO 2 loading and Henry's law constants. Krichevsky–Kasarnovsky equation was used to correlate the solubility data and obtain Henry's law constants at 303.15 K. Finally, the effects of hydrogen bonding within DESs, molar ratio, molar volume, free volume, ether group and alkyl chain length were investigated based on CO 2 solubility in DESs. To the best of our knowledge, this is the first time CO 2 solubility in these DESs was studied.

Recently, deep eutectic solvents (DESs) as the new solvents have received considerable amount of attention between researchers in different research fields and are under investigation so find out their potential to become a versatile alternative to ionic liquids (ILs) and traditional solvents. DESs are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). Six DESs were synthesized namely allyltriphenylphosphonium bromide-diethylene glycol (ATPPB-DEG) and allyl-triphenylphosphonium bromide-triethylene glycol (ATPPB-TEG) using three mole ratios of 1:4, 1:10 and 1:16 salt to HBDs. In this work, we report physicochemical properties of these DESs, which include density , molar volume, isobaric thermal expansion, refractive index, specific refraction, molar refraction, free molar volume, electronic polarization and internal pressure at several temperatures from 293.15 K to 343.15 K. Most of these properties are fitted to a linear equation by the method of least-squares using the Levenberg-Marquardt algorithm to derive the corresponding parameters and estimate the root mean square error (RMSE) and least squared correlation coefficient (R 2).

The solubility of CO2 in aqueous solutions 30 wt% monoethanolamine (MEA) mixed with various glycerol concentrations was measured. The CO2 absorption was performed at three different temperatures (313, 323, and 333 K), and pressures ranging from 500–1500 kPa with concentrations of glycerol in the mixture varying from 0 to 20 wt%. Correlations of solubility as a function of CO2 partial pressure were obtained with deviation of less than 2% over the pressure range investigated. The CO2 loading at various temperatures, pressures, and concentrations showed an agreement to the general trend of absorption (i.e., increasing the equilibrium loading with decreasing the temperature and increasing the pressure). The solubility of the MEA solution
increased by adding glycerol up to a level of 10% at lower pressures. The findings showed that 5 wt% glycerol in the mixture was the concentration that yielded the optimum CO2 solubility as it could increase the CO2 solubility of MEA at low pressures and approximately maintain its capture performance at high pressures. It confirmed that the solvent is suitable for the absorption of CO2 under low pressures (below 1000 kPa) and can be applied in low-pressure CO2 absorption processes such as post-combustion CO2 capture.

The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination.

Solid sorbent from functionalized activated carbon (AC) could enhance the adsorption capacity in CO2 capture. This study emphasizes cyclic CO2 capture using NiO functionalized AC. Different loadings of NiO impregnated on AC were synthesized. This work showed that the most efficient adsorbent of 0.05NiO/AC exhibits an adsorption capacity of 55.464 mg/g at the adsorption temperature of 30 °C by using the temperature swing adsorption method. A slight loss of adsorption capacity at 0.28 % for a five cycles CO2 capture indicated consistency potential for large scales application. The adsorbent exhibited a slightly lower surface area compared to AC, but the presence of NiO improved the adsorption capacity by chemisorption phenomena. The NiO acts as the basic site for CO2 capture. Meanwhile, AC as support could increase the surface area of active sites and reduce the sintering effect of the NiO. It was found that various adsorption temperatures had a good correlation with the pseudo-second-order kinetic model. The magnitude of the sorption process was evaluated by the activation energy of 48.09 kJ/mol, which implies a chemisorption process at various adsorption temperatures. Thermodynamic studies explained the CO2 adsorption process for this study was found to be a spontaneous and endothermic process.

The deployment of post-combustion CO 2 capture on large-scale gas-fired power plants is currently progressing, hence the integration of the power and capture plants requires a good understanding of operational requirements and limitations to support this effort. This article aims to assist research in this area, by studying a micro gas turbine (MGT) integrated with an amine-based post-combustion CO 2 capture unit. Both processes were simulated using two different software tools eIPSEpro and Aspen Hysys, and validated against experimental tests. The two MGT models were benchmarked at the nominal condition, and then extended to part-loads (50 and 80 kW e), prior to their integration with the capture plant at flue gas CO 2 concentrations between 5 and 10 mol%. Further, the performance of the MGT and capture plant when gas turbine exhaust gases were recirculated was assessed. Exhaust gas recirculation increases the CO 2 concentration, and reduces the exhaust gas flowrate and specific reboiler duty. The benchmarking of the two models revealed that the IPSEpro model can be easily adapted to new MGT cycle modifications since turbine temperatures and rotational speeds respond to reaching temperature limits; whilst a detailed rate-based approach for the capture plant in Hysys resulted in closely aligned simulation results with experimental data. Crown

Amino acid functionalized 1-methyl-3-ethyl-imidazolium based ionic liquid (IL) supported on ordered
mesoporous silica (OMS-IL (AA)) were prepared via grafting method and were applied as solid sorbent
for CO2 adsorption–desorption. Four different kinds of amino acids (AA), including lysine (Lys), glycine
(Gly), alanine (Ala), and proline (Pro) were selected in order to prepare different OMS-IL (AA) adsorbents.
The developed solid adsorbents were characterized by using 29Si-NMR, FT-IR, TGA, BET, SEM, TEM, and
elemental analysis. The CO2 adsorption–desorption studies were carried out using the thermogravimetric
method with temperature swing assistance of the adsorbed CO2. Evaluation of CO2 adsorption nature
revealed that the adsorbents show fast kinetics, moderate chemisorption and easy desorption. Among
the synthesized OMS-IL (AA), OMS-IL (Lys) showed the best CO2 adsorptive performance corresponding
to 0.61 mmol/g at 25
C. The energy requirements for activation, adsorption and desorption are estimated
by using different methods to meet its energy criteria. Further, the approach has been made to discuss the
activity of selected amino acids, their effective loading, kinetics, and adsorption capacities in detail. DFT
studies reveals that the energy required for CO2 adsorption on IL (Lys) is high enough for CO2 uptake
(=0.98 eV). According to experiment and DFT calculations, a worthy correlation is identified between
CO2 adsorption capacity, adsorption energy, and the orbital localization, which determines the basic role
of ILs over support to adsorbed CO2 efficiently.

In this study, a novel system for contacting gases and liquids, which may be suitable for many applications involving gas-liquid contact or gas-liquid reactions, has been developed and characterized. The system consists of a vertical vessel with gas and liquid ports and inert particles. The gas is injected through a single orifice at the bottom of the vessel and leaves at the top, while the liquid feed is introduced at the top, and the effluent leaves at the bottom of the vessel through a vertical tube inserted from the top all the way to the bottom. The system involves the use of inert particles that create circular motion within the vessel, enhancing mixing and providing high gaseliquid interfacial area for effective mass transfer. The contactor system was evaluated for the capture of CO 2 through reactions with ammonium hydroxide and saline wastewater, namely desalination reject brine. The effect of inert particles surface area on both CO 2 capture and ions removal was evaluated. The liquid residence time distribution (RTD) was also evaluated for experiments with and without the mixing particles, using sodium hydroxide as a tracer. In addition, the system dynamic behavior was assessed through step changes in the gas flow rate, liquid flow rate and temperature. The reactor system showed high reaction efficiency, excellent mixing and very stable steady state.

A nivel mundial se tiene presente que ciertos fenómenos meteorológicos, así como "patrones climáticos", han sufrido cambios en frecuencia, intensidad, duración y época en la que se dan, esto en función de los registros y se nota en la lluvia, viento, temperatura, deshielo de glaciares, por decir algunos.

One of the most promising technologies to reduce global emissions of CO 2 as a major greenhouse gas is called calcium looping (CaL). Current calcium-oxide-based sorbents used in CaL process either expensive or lose their effectiveness over many cycles. On the other hand, the negative impact of large amounts of waste marble powder generated by cutting and polishing marble on the environment cannot be ignored. With the aim of cleaning up both carbon emissions and waste at the same time, therefore, this study will investigate the application of inexpensive waste marble powder as potential alternative to current commercial calcium-carbonate sorbents for capturing CO 2. The marble powder-based sorbents were characterized by SEM-EDS, XRD, TGA, XRF and N 2 sorption analysis. To improve the CO 2 capture performance, the waste marble powder was modified with several various acids. The results revealed that an increase in the acid volume has changed the CO 2 uptake capacity and stability of sorbents particularly propionic acid (PA) and acetic acid (AA). It was found that the carbonation conversion of modified sorbents with AA-50% and MD PA-50 were 70.2% and 76%, respectively, higher than that of unmodified CaO sorbent after 20 cycles. In terms of CO 2 uptake capacity, modified sorbent with PA-50% showed the highest performance of 0.675 g CO 2 /g sorbent, while, modified sorbent with AA-50% showed improved cyclic stability over multiple cycles (average decay 1.24 mg CO 2 /cycle) regarding the stability. Therefore, these results indicate that (acid-modified) CaO derived from marble powder is much better sorbent than limestone and can be used as a low cost and environment-friendly sorbent for CO 2 capture.

A new model is proposed to find the density of saturated ternary solutions of H2O–CO2–NaCl in the temperature range of 50–100◦C and pressures up to 600 bar. The model calculates the partial molar volume of dissolved CO2 from the density of saturated binary, H2O–CO2, solution and the corresponding mole fraction of dissolved CO2. The density of the saturated binary solution is determined as a function of temperature and pressure from a regression of experimental data. The mole fraction of dissolved CO2 is obtained from the Redlich–Kwong equation of state. The partial molar volume of CO2 obtained in his manner is then made to coincide with one solution branch of the Redlich–Kwong equation while retaining the other solution branch associated with the molar volume of the gas phase. This allows the simultaneous calculation of both the gas and the liquid molar volume with a single equation of state. The density of the saturated ternary solution predicted by the new model is found to be in good agreement with experimental data. The new model is then used to characterize the effects of temperature, pressure and salinity on the onset of buoyancy driven convection during CO2 sequestration.

Corrosion mitigation was evaluated at 80°C in a naturally aerated 30 wt.% monoethanolamine (MEA) solution with a CO2 loading of 0.43 molCO2/molalkalinity for a FeCO3 coated A106 carbon steel sample fabricated from solutions of NaHCO3 and piperazine with CO2 loading. The results showed that spontaneous passivation of A106 carbon steel was promoted by this FeCO3 coating, which resulted in a Fe3O4 layer formation. FeCO3 was metastable in this aerated MEA solution and eventually would transform into Fe3O4. Overall, the FeCO3 coating reduced the corrosion rate by a factor of 70. In this case, a semi in-situ process to form and/or recover a dense FeCO3 layer to mitigate corrosion in a post-combustion CO2 capture system is proposed. Due to its more environmentally friendly nature, easier process control, and faster FeCO3 coating synthesis, NaHCO3 is recommended as a FeCO3 fabrication solution with respect to piperazine solution with CO2 loading.

EGR is a way to enhance the CO 2 content with reduction in design variables and cost. Both process and economic analyses are essential to reach the optimum design variables. Commercial-scale NGCC with and without EGR is presented. Process design of the amine-based CO 2 capture plant is evaluated for with and without EGR. a b s t r a c t Post-combustion CO 2 capture systems are gaining more importance as a means of reducing escalating greenhouse gas emissions. Moreover, for natural gas-fired power generation systems, exhaust gas recir-culation is a method of enhancing the CO 2 concentration in the lean flue gas. The present study reports the design and scale-up of four different cases of an amine-based CO 2 capture system at 90% capture rate with 30 wt.% aqueous solution of MEA. The design results are reported for a natural gas-fired combined cycle system with a gross power output of 650 MW e without EGR and with EGR at 20%, 35% and 50% EGR percentage. A combined process and economic analysis is implemented to identify the optimum designs for the different amine-based CO 2 capture plants. For an amine-based CO 2 capture plant with a natural gas-fired combined cycle without EGR, an optimum liquid to gas ratio of 0.96 is estimated. Incorporating EGR at 20%, 35% and 50%, results in optimum liquid to gas ratios of 1.22, 1.46 and 1.90, respectively. These results suggest that a natural gas-fired power plant with exhaust gas recirculation will result in lower penalties in terms of the energy consumption and costs incurred on the amine-based CO 2 capture plant.

Mesoporous MgO-TiO2 sorbents denoted as (xMgO-TiO2) with different Mg/Ti molar ratios were synthesized by single step evaporation-induced self-assemble (EISA) method for its application to CO2 capture.
The effect of Mg/Ti molar ratio of mesoporous MgO-TiO2 sorbents on their physicochemical properties,
oxidation state of titanium, and CO2 adsorption performance was investigated. The phase of xMgOTiO2 was transformed in the sequence of MgTiO3 (Mg/Ti = 1.0 and 2.0) ? MgO-MgTi2O4 (Mg/Ti = 3.0
and 4.0) ? MgO-Mg2TiO4 (Mg/Ti = 5.0). However, with the increasing Mg/Ti molar ratio, CO2 adsorption
performance increased in the order of MgTiO3 < MgO-MgTi2O4 < MgO-Mg2TiO4. Among the sorbents
tested 3.0MgO-TiO2 showed the best CO2 adsorption performance corresponding to 1 mmol/g
(4.39 wt.%). It was observed that the MgTi2O4 (Ti3+-O-Mg2+) could create highly basic sites compared
to MgTiO3 and Mg2TiO4. In the process of CO2 adsorption, high surface area (111.4 m2/g), large pore volume (0.45 cm3/g) as well as appropriate basic sites of Mg-O-Ti make it a plausible candidate for CO2
adsorption.