Greenhouse Gases: Science and Technology最新文献

This study introduces a novel approach to promote CO₂ absorption by aqueous K₂CO₃ solutions through the in-situ generation of reactive oxygen species (ROS) via the alkali activation of H₂O₂. The superoxide radical anion (O₂^•-) is recognized as a major contributor in this process, with its presence confirmed by UV-Vis (Ultraviolet–visible) spectroscopy through the characteristic diformazan peak formed from the reaction between nitro blue tetrazolium (NBT) and superoxide. CO₂ absorption experiments and ¹³C NMR (Carbon-13 nuclear magnetic resonance) characterization demonstrate the enhanced efficiency of the promoted solution in both CO₂ absorption and the conversion of K₂CO₃ to KHCO₃. Comparative analysis with traditional promoters reveals the superior kinetic performance of the H₂O₂-promoted system at room temperature. Notably, our system yields pure KHCO₃ without by-products, making it highly suitable for carbon capture and utilization (CCU) by enabling versatile subsequent transformation processes. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Carbon dioxide (CO₂) in the supercritical state, being denser yet less viscous, is suitable for long-distance transportation. Despite this well-known principle, implementing an operational scheme with appropriate inlet pressure and mass flow rate for supercritical CO₂ (srCO₂) transportation is challenging due to the complex interplay among state variables, fluid properties, pipeline dimensions and materials, and the intricate boundary and ambient conditions surrounding the pipeline. This paper utilizes PIPESIM software to conduct a feasibility study of srCO₂ transportation over a 10-mile-long model pipeline in the Cook Inlet region of Alaska, USA. The study aims to understand the limitations of operational parameters and develop a scheme for selecting feasible parameters for srCO₂ transportation. Considering geographic location, elevation profiles, and ambient conditions, the simulations calculated pressure and temperature profiles, erosion kinetics, and fluid states for various conditions derived from a combinatorial set of pipeline diameters ranging from 11 to 16 in, inlet pressures between 1,400 and 1,900 psia, and mass flow rates from 10 to 275 lbm/s, with an inlet temperature of 200 °F. The major findings indicate that larger pressure losses are expected in smaller pipelines that are well-insulated and/or operated at lower inlet pressures. Turbulent flow is more likely to occur in smaller pipelines and at higher mass flow rates, potentially altering the state of the transported fluid. The parametric modeling results provide a scenario-driven approach to determining a feasible range of mass flow rates, pipeline inner diameters, and inlet pressures for srCO₂ transportation. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Ventilation air methane (VAM) is one of the main greenhouse gas sources. Owing to the characteristics of low concentration of ventilation air methane and high moisture content, we build an experimental platform and take the oxidative combustion temperature and methane conversion rate as the research indexes, and the systematic research finds that the inhibitory effect of moisture on the oxidative combustion of ultra-low concentration of methane (<1%) is a nonlinear polynomial law. In the meantime, we constructed OH(H₂O)_n+CH₄ and studied its reaction potential energy surface using quantum chemical calculations, which used the most significant primitive reaction of methane combustion, OH+CH₄→H₂O+CH₃, as the theoretical basis. We found that as moisture content increased, so did its reaction energy barrier, making the reactants more stable, strengthening the three-body collision effect, and reducing the number of free radicals, all of which hindered the methane chain reaction. The study aimed to validate the experimental finding that moisture inhibits the oxidative combustion of ventilation air methane by examining the internal mechanism of methane oxidation. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

CO₂ separation technology at low pressure is most desirable in carbon capture projects to mitigate global warming. Facilitated transport membranes offer selective and effective CO₂ permeation using a wide range of carbon carriers at low pressure. Porous fillers were recently included as they can carry abundant fixed carriers besides offering open channels for CO₂ permeation. This study investigates the effects of amine-modified zeolitic imidazolate framework-8 (ZIF-8) with well-defined micropores and gas sieving ability in polyvinyl alcohol (PVA) membranes containing an ionic liquid that worked as mobile carriers. The effects of amine-modified ZIF-8 and silica nanoparticles on membrane properties and separation performance were also compared. Fourier transform infrared spectra confirmed the incorporation of ZIF-8, secondary amine, IL anions, and silica nanoparticles in PVA membranes. Energy dispersive analysis showed the good dispersion of inorganic fillers. The amine-modified silica nanoparticles resulted in higher thermal stability compared to the amine-modified ZIF-8 in PVA membranes containing [bmin][Ac] ionic liquid, as shown in the thermogravimetric analysis. However, the CO₂ separation performance of PVA membranes containing [bmim][Ac] ionic liquid was improved more significantly by the amine-modified ZIF-8 with microporous structure. A CO₂/N₂ ideal selectivity of 85.65 and CO₂ permeance up to 4,502.91 GPU were attained. Unlike the CO₂/N₂ ideal selectivity, the CO₂ permeance was not significantly affected either using [bmin][Ac] or [bmin][BF₄]. The humid gas greatly enhanced the CO₂ permeance without much changes in the CO₂/N₂ ideal selectivity due to the promotion of facilitated transport. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Underground biomethanation, which relies on the subsurface microbial activity to convert hydrogen and carbon dioxide into methane, is a promising approach to support carbon capture, utilization, and storage technology. The process involves injecting hydrogen with captured CO₂ into depleted oil and gas reservoirs or aquifers colonized by hydrogenotrophic methanogens that can convert these two substrates into methane. Despite the attractiveness of this technology, there are still uncertainties about the efficiency of the conversion process, particularly the impact of microbial parameters. To investigate the efficiency of the hydrogen conversion process, we relied on a bio-reactive transport model that can mimic microbial growth and decay, consumption of substrates, and transport of reactants and products. It was found that the methane concentration peaks near the injection well when the hydrogen fraction is in the range of 75% to 80% of the injected gas composition. In addition, a noticeable hydrogen sulfide concentration can be produced due to sulfide ions in the brine. Using the Kozeny-Carman relation, an attempt was made to correlate microbial growth with reduced porosity and permeability. It was then revealed that substrate consumption by microbes leads to a drastic increase in the microbial population in the subsurface, which can reduce the petrophysical properties of the reservoir, especially in the near wellbore area. The results obtained from a series of parametric analyses showed that the hydrogen concentration in the injected gas, pressure, well spacing, and injection rate are some of the most important parameters contributing to the biomethanation process. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

In this work, an alkali melting-pickling assisted solid phase synthesis method of S-1 zeolite molecular sieve with excellent adsorption properties for CO₂ was successfully developed by using solid waste fly ash. SiO₂ with a purity of up to 97.84% was successfully extracted by using alkaline fusion activation, high temperature calcination and pickling. The CO₂ adsorption capacity of the prepared SiO₂ was 0.51 mmol/g at 298 K and 1 bar. Silicalite-1 molecular sieve was prepared by solid phase synthesis method using SiO₂ extracted from fly ash as silicon source. The results showed that the prepared Silicalite-1 had good morphology and relatively high crystallinity. The specific surface area is 623.30 m²/g, and the total pore volume is 0.31 cm³/g. In addition, the adsorption capacity of CO₂ was 2.05 mmol/g at 298 K and 1 bar. Compared with the prepared SiO₂, the adsorption capacity of CO₂ by Silicalite-1 molecular sieve increased by four times. Moreover, under the test condition of 298 K, it has a high selectivity coefficient for CO₂/N₂ mixed gas, and after 10 times of adsorption-desorption cycle tests, the adsorption capacity of Silicalite-1 molecular sieve for CO₂ does not change significantly, and its adsorption rate can still be as high as 89.31%. The results indicate that Silicalite-1 molecular sieve prepared by solid phase synthesis method has good adsorption selectivity and adsorption–desorption cycle regeneration stability, and can be used in the field of CO₂ adsorption, separation and purification. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

During CO₂ storage in deep saline aquifers, the presence of residual water has an important influence on the storage efficiency and safety. In this study, natural rock cores taken from deep reservoirs in the Ordos Basin and Fukang, Xinjiang are used as research objects. Nine groups of core-flooding experiments are performed under different CO₂/N₂ gas mixture ratios to study the influence of rock properties (mineral composition, permeability, porosity and pore structure) on the residual water. Furthermore, the geophysical and chemical properties of rock cores are analyzed by X-ray diffraction, electron microscopy, field emission scanning electron microscopy and piezoelectric mercury method. The results show that residual water saturation is a quantitative power function of drainage time. The residual water saturation is positively correlated with the total amount of quartz and feldspar and increases with increasing permeability. Moreover, both the average and median pore throat radius show a strong inverse correlation with irreducible residual water saturation; as these radius increase, the residual water saturation decreases. In contrast, the porosity and maximum pore throat radius display a weaker correlation with irreducible residual water saturation. This study is of great value for engineering practices such as the site selection of CO₂ storage projects in saline aquifer and improvement of CO₂ storage efficiency. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Membrane contactor has emerged as a promising technology for flue gas carbon capture as it integrates the advantages of high capture efficiency of absorption technology and compact design of membrane technology. However, the integration performance could be affected by the presence of minor components such as water vapor and residual oxygen in real gas conditions, owing to vapor condensation and dynamic oxidation in gas-liquid transfer interface. Therefore, it remains a need to develop a model that enables the prediction of CO₂ removal performance of membrane contactor under industrial real gas conditions. In the present study, a multicomponent model considering the impact of water vapor and oxygen on CO₂ removal in membrane contactors was developed. The model, based on mass transfer equilibrium, gas reaction kinetics, and diffusion coefficients, describes the transport and reaction dynamics of multicomponent gases within the gas, liquid, and membrane phases. Utilizing the finite element method (FEM) for solution, the model was demonstrated with a case study of CO₂ separation from a quaternary gas mixture by a hollow fiber membrane contactor (HFMC). The results highlight the importance of considering water vapor and oxygen in the design and evaluation of industrial membrane contactor systems, offering valuable insights for enhancing CO₂ separation efficiency in practical applications. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

During the early screening phase of Carbon Capture and Storage (CCS) site evaluations limited time and data are available and hence CO₂ plume evaluations using time and data intensive reservoir simulations are almost never performed. However, there is still a need for early plume evaluations to risk and rank injection sites relative to each other. Therefore, an alternative fluid migration method called invasion percolation is adopted for the CCS screening phase to predict the extent and location of CO₂ plumes in the subsurface. Invasion percolation as part of basin modeling is a rapid method, which requires limited data and is ideal for the early screening phase. Invasion percolation results are compared to uncalibrated reservoir models, typical for the screening phase, revealing that plume location shape and size are very reasonable especially when compared to seismic observed plume outlines. It can be concluded that invasion percolation as part of basin modeling is a fit for purpose method, which can assess multiple opportunities rapidly during the early intake screening phase to risk and rank opportunities relative to each other and to build a CCS injection site portfolio. In addition to the plume evaluation, basin models can provide useful basin-scale or injection site specific pressure and temperature predictions as well as CO₂ density estimates for static volume calculations before detailed reservoir and stratigraphic models are available. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

We have previously proposed amino acid salts solutions as potential absorption liquids for direct air capture (DAC) of CO₂ from the atmosphere. However, little is known about their relevant CO₂ solubilities, CO₂ mass transfer rates, and susceptibility to oxidative and thermal degradation under conditions relevant to DAC. We report here on the overall solubility of CO₂ and CO₂ mass transfer rates into a series of amino acid salts solutions. Additionally, the robustness of various amino acid salt solutions to thermal and oxidative degradation has been assessed.

CO₂ absorption rates into the amino acid salts solutions were observed to be in the same order of magnitude as aqueous monoethanolamine (MEA), with sarcosinate and lysinate solutions providing the fastest and slowest CO₂ mass transfer rates at 25°C, respectively. Degradation data revealed that all amino acid salt solutions investigated in this study displayed elevated rates of thermal degradation at both 120 and 150°C relative to MEA. The opposite trend was observed with respect to oxidative degradation where all amino acid salt solutions showed a greater resistance to oxidative degradation than that observed for MEA under the conditions investigated here. Considering the degradation, CO₂ absorption capacity, and CO₂ mass transfer rate data, we propose the potassium salts of proline and sarcosine as the most promising amino acid salts (of those considered here) for further evaluation in DAC processes. Overall, this study provides valuable insight into the suitability of various amino acid salt solutions as absorption liquid for DAC. © 2024 The Author(s). Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.