Greenhouse Gases: Science and Technology最新文献

Modeling of CO₂ removal in a rotating packed bed using a mixed amine solution of piperazine and methyldiethanolamine with various molar concentration ratios was done with Aspen Plus^® and dynamically linked with Intel^® Visual Fortran. In addition to the mass and energy balances, all the necessary correlations for the rotating packed bed were written in Intel^® Visual Fortran. The developed model was validated, and the result showed good agreement with a percentage error of less than 10%. The model was scaled-up to absorb CO₂ from the flue gas composition of a typical 6.4 MWe biomass power plant with the goal of producing net negative CO₂ emissions. The effect of process parameters such as temperature, rotation speed, liquid-gas ratio, methyl diethanolamine concentration, and piperazine concentration on capture efficiency and regeneration energy was investigated. It was discovered that increasing the rotational speed results in an improvement in the separation efficiency. Increasing the temperature of the lean solvent causes a decrease in separation efficiency, which is due to a decrease in solubility as the temperature increases. Increasing the liquid-to-gas ratio leads to an increase in CO₂ absorption efficiency because more hydroxide ions are present to react with the CO₂. Piperazine is a reactive compound and increasing its concentration in the mixed solvent leads to an increase in CO₂ absorption efficiency. Finally, the results of the study demonstrated that a solvent mixture consisting of piperazine and methyldiethanolamine has the potential to be utilized in post-combustion CO₂ capture using rotating packed bed technology. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

The far-reaching impacts of climate change have further strengthened the determination of governments around the world to pursue low-carbon development, and low-carbon efficiency in less developed regions has become a “shortcoming” in realizing low-carbon aspirations. We analyze the carbon emission efficiency (CEE) and its temporal evolution in less-developed regions in developing countries, such as Western China. The differentiation of Western China was evaluated in terms of spatial and influencing factors through the Theil index and the logarithmic mean divisia index (LMDI), and the innovative use of GDP gold content (GDP_gc) to represent the absolute economic level in the Theil index. Considering the net carbon emissions (NCE) are undesirable outputs, the GDP_gc is taken as the desired output. The Un-Super-SBM-CRS method obtained the net carbon emission efficiency (NCEE) values. The results show that: (1) Western regions’ NCE differences can be categorized as high per capita NCE areas (more than 25 tons), medium per capita NCE areas (10–25 tons), and low per capita NCE areas (0–10 tons). (2) The per capita-based T (Theil index) and the GDP_gc are comparable and “intra-group convergence and inter-group differentiation” can be used to describe intra-regional and inter-regional NCE differences. (3) Both the level of the economy and the level of urban development are drivers of the 11 domains, and the level of the economy is driven more than the level of urban development overall. There are significant regional differences in other factors. (4) The NCEs and their evolutionary trends in each region can be divided into single-variable and fluctuating-variable. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

In the context of global climate change, carbon capture and storage (CCS) has become a direct and effective measure for reducing greenhouse gases emission. However, injecting CO₂ into the subsurface reservoirs may pose risks related to geological hazards. Therefore, monitoring the variations in underground temperature fields, strain fields, and vibration fields induced by CO₂ injection is essential for predicting and controlling geological hazards. Distributed fiber optic sensing (DFOS) technology, with its unique features, enables real-time monitoring of temperature, strain, and vibration. By deploying fiber optic (FO) cables inside wellbores, a DFOS can be used to effectively capture multiple underground response parameters. This paper reviews the applications of DFOS technology in CO₂ geological sequestration. The chapter covers aspects such as the literature review, principles and applications of fiber optics, and representative monitoring projects. Finally, the paper discusses the challenges and proposed solutions for DFOS technology in this context. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

The objective of this study is to assess the storage of acid gas, containing CO₂ and H₂S, in a depleted naturally fractured reservoir (NFR) using single matrix block (SMB) approach. The acid gas dissolution in oil is considered by Peng-Robinson equation of state and compositional simulation. The PHREEQC package is used to determine acid gas solubility in formation brine. Three types of acid gases with different compositions are used for this study and their swelling behavior and miscibility in relation to the reservoir oil are analyzed. An SMB model, with a matrix block surrounded by fractures, is constructed, and validated for simulation of a real experiment. The simulation is conducted for synthetic and real reservoir fluids when the oil is in its residual saturation. A sensitivity analysis is performed to study the effects of key parameters, such as acid gas composition, reservoir pressure, permeability, porosity and matrix height on the storage capacity and oil recovery factor. The matrix has a volume of 27 m³ and about half of acid gas storage is achieved in the first 5 years while the simulations are run for 30 years. The results show that up to 90% of remained oil is recoverable, and more than 0.67 kmol of acid gas per cubic meter of matrix is stored whether matrix contains a real oil or a synthetic one. Higher storage is achieved for higher matrix porosities and heights and large H₂S proportion in acid gas. In all cases about 10% of acid gas is trapped in water and the remaining 90% is dissolved in oil. The mineral trapping was more active in CO₂-rich acid gases. While about 10 kg of the matrix rock was dissolved in the acidic brine when the acid gas contained H₂S, the amount of the dissolved minerals in acidic brine resulted from the injection of CO₂-rich acid gas was more than 16 kg. Finally, this study gives a comparative analysis of the storage performance of acid gas mixture and pure CO₂. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

This research applied a concurrent activation and surface modification (CAM) process to synthesize palm kernel shell-derived activated carbon (PKSdAC) to obtain CO₂ affinity surface functionalization. The CAM process is a simplified activated carbon activation process that is cost-effective. The CAM process used in this study integrates sulphuric acid activation and barium chloride functionalization. The formation of barium sulphate is targeted to incorporate barium through a reduction process with carbon-containing material at elevated temperatures into PKSdAC to obtain basic metal surfaces functional group for chemical adsorption. The optimal temperature for CAM-PKSdAC CO₂ adsorption performance was at 40–60 °C, established through temperature-programmed desorption of CO₂ (TPD-CO₂) analysis. The CAM-PKSdAC adsorption performance was tested using a lab-scale adsorption system. The bed CO₂ content was determined using gas chromatography coupled with a thermal conductivity detector (GC-TCD) by manual syringe injection. CAM-PKSdAC exhibited a high CO₂ adsorption capacity of 0.89 mmol g⁻¹ from TPD-CO₂, and 1.91 mmol g⁻¹ from GC-TCD at 40 °C and 1 bar. It showed comparable CO₂ adsorption capacity to conventional surface modified-activated PKSdAC (1.96 mmol g⁻¹) while higher than commercial and modified ACs (1.14–1.60 mmol g⁻¹), but lower than potassium hydroxide modified ACs (1.81–2.10 mmol g⁻¹) at 40 °C and 1 bar. Barium promoted chemisorption of CO₂ as supplementary reaction, which increases adsorption capacity. The non-linear Dubinin Radushkevich model strongly correlates with the experimental adsorption data for CAM-PKSdAC adsorption, indicating the physisorption process via micropore filling on CAM-PKSdAC. CAM-PKSdAC showed moderate reusability with negligible variation in adsorption capacity after 10 adsorption–desorption cycles. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

CO₂ huff and puff is a widely used enhanced oil recovery method in many oil fields, but its implementations in shale fields is scarce. This paper reports trials of CO₂ huff and puff in a shale field in China. Laboratory studies revealed that CO₂ effectively reduced oil viscosity, increased oil volume, and improved oil recovery under miscible conditions. For the three wells that received CO₂ huff and puff treatments, one well showed satisfactory results, while the other two wells demonstrated poor economics. Discussions and recommendations are made based on field experiences. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Urban environments play a significant role in global carbon emissions and sequestration, necessitating a comprehensive understanding of their spatial distribution. This study presents a micro-scale spatial modeling framework to elucidate the complex interplay between CO₂ sources and sinks within urban settings. Utilizing advanced geospatial analysis, remote sensing data, and geographically weighted regression (GWR) modeling techniques, we provide a detailed characterization of emission patterns and identify the spatial distribution of carbon dioxide sequestration. Employing the bottom-up method and geographic information system techniques, we quantified carbon dioxide emissions in Isfahan City, Iran, attributing 81.68% to stationary combustion sources (residential, commercial, industrial, and power plant sectors) and 18.32% to mobile combustion sources (road-rail transportation, and non-road transportation [agricultural machinery]). To model carbon sequestration, we calculated tree biomass using allometric equations and estimated carbon sequestration per tree unit. Subsequently, we employed GWR to map the spatial distribution of carbon deposition across the city. The results revealed an annual carbon sequestration capacity of 7,704 tons, equivalent to storing 28,275 tons of CO₂. Our findings highlight the substantial contribution of urban areas to greenhouse gas emissions and the potential of urban green spaces to mitigate these emissions. The spatial modeling framework developed in this study provides a valuable tool for urban planners to optimize carbon management strategies and promote sustainable urban development. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

For shallow buried mines, the cracks generated due to the mining activities will connect the surface ground and the working face through the gob, which may result in the gas exchange between the surface and underground. In this study, we proposed the gob gas flow model and verified its applicability based on the measured data on site in our previous research and discussed the effect of delay time of pressure variation between working face and surface ground on the airflow direction according to the simulation. The results suggest that the delay time of pressure variation is the main factor affecting the pressure difference between surface and working face and airflow direction. Due to the characteristics of the surface pressure changes, the effect of delay time on airflow in gob is small in a short time, but this effect gradually increases with time. According to the airflow law in a cycle of pressure variation, the airflow direction in the gob is predictable when the delay time reaches a certain value, which can be interpreted clearly on the surface pressure variation diagram. This research may provide references for the measures taken against mine disasters caused by different airflow directions. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

CO₂ capture by absorption and stripping with aqueous amine is a well-understood and widely used technology. However, drawbacks still exist in the practical applications, such as high energy consumption and easy degradation of the absorbents during the desorption process. In this paper, a novel NE-1 absorbent was developed, and its suitable operating conditions were determined: concentration (45 wt.%), absorption temperature (40 °C), and desorption temperature (100 °C). The NE-1 absorbent exhibits a high CO₂ absorption capacity of 3.73 mol/kg, 1.33 times that of 30% monoethanolamine (MEA). After optimizing with carbamide as a corrosion inhibitor, 45% NE-1a1 may attain an effective CO₂ capacity of 2.5 mol/kg and over 70% desorption rate in five cycles, demonstrating excellent cycling stability performance. The research results have significant implications for developing an efficient and stable commercial carbon capture solvent and promoting the development of carbon reduction technologies. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

To effectively utilize ventilation air methane (VAM), it is proposed to pass it into the boiler of the coal-fired power plant for mixed combustion. However, the different types of thermal coal utilized present distinct characteristics when mixed with VAM. In this paper, lignite, bituminous coal, and anthracite are selected to study the CH₄ conversion rate, system ignition temperature, and NO emission characteristics of the VAM-pulverized coal coupled system on a fluidized bed experimental platform. The experimental results show that the ignition temperatures of VAM are 748, 736, and 732 °C when the CH₄ concentration is 0.25, 0.5, and 0.75%. After the addition of thermal coal, the ignition temperature decreased significantly. When the CH₄ concentration is 0.25%, the ignition temperature of the lignite-VAM system is the lowest, which is 450 °C. Anthracite has the strongest catalytic effect on CH₄ combustion. When the heating rate is 5 °C /min, the reaction rate of CH₄ is the fastest in the anthracite-VAM coupled system. Under laboratory conditions, the peak NO concentration in the coal-VAM coupled system was lignite > bituminous coal > anthracite at different CH₄ concentrations, and the CH₄ in VAM had a reducing action on the NO generated during mixed combustion, with a stronger reducing effect observed as the CH₄ concentration increased. The results of this study can lay the foundation for the industrial application of the mixed combustion of VAM and thermal coal, and be of great significance for solving the practical problems caused by the change of boiler coal types. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.