Greenhouse Gases: Science and Technology最新文献

This paper addresses the urgent challenge of CO₂ emissions and the need for sustainable energy sources. It emphasizes CO₂ hydrogenation as a promising solution for large-scale long-term energy storage, converting CO₂ into valuable fuels using green hydrogen generated from renewable sources. The study concentrates on exploring pathways leading to oxygenated compounds, such as alcohols or ethers, for their utilization as sustainable fuels. The investigation encompasses methanol, dimethyl ether, ethanol, and higher alcohols. The paper investigates catalysts for CO₂ hydrogenation, ranging from traditional metal-based to advanced materials, aiming to identify efficient and stable catalysts for synthesizing oxygenated compounds. Catalysts are indispensable in CO₂ hydrogenation for the synthesis of oxygenated compounds, contributing to improved reaction kinetics, selectivity, economic viability, reduced environmental impact, and the overall sustainability of the process. The goal is to contribute to a fully renewable, carbon-neutral system powered by excess solar and wind electricity, where recycled CO₂ and green hydrogen are used to produce fuels, to be stored and then used to produce energy, electricity, heat, or mechanical energy, on demand, with the capture of the CO₂, in a system which is overall carbon neutral. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

CO₂ hydrate technology can be applied to seawater desalination. However, the kinetics of CO₂ hydrate formation were inhibited in the aqueous solution with inorganic salts, and the kinetic mechanism of CO₂ hydrate formation for inorganic salts with different metal cations and anions was still unclear. In this work, CO₂ hydrate nucleation and growth were studied in aqueous solutions of metal chlorides. Instead of Na⁺ and K⁺ ions, CO₂ hydrate nucleation was promoted in the presence of Ni²⁺, Mn²⁺, Zn²⁺ and Fe³⁺ ions due to the co-ordination bonds between transition metal ions and water molecules to enhance the formation of the critical crystal nuclei. The induction time was increased by 61.1% in aqueous solution with 0.32 mol/L NaCl, while it was shortened by 55.6% in FeCl₃ aqueous solution at the same concentration of Cl⁻ anions. In the process of CO₂ hydrate growth, Cl⁻ ions played a more important role than the metal ions in affecting the stability of CO₂ hydrate cages. The gas storage capacity was reduced by 10.3% in the presence of NaCl, and was lower than that of other metal chlorides. Cl⁻ anions were absorbed on the hydrate surface and involved in hydrate cages to inhibit the hydrate growth due to the hydrogen bonds between the Cl⁻ ions and water molecules of the hydrate cages. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Amine-functionalized porous polymers have been considered as a prominent chemical adsorption material for carbon capture and storage (CCS) process, because of their large adsorption capacity and high selectivity. By comparison, the low energy-consumption for desorption and high recyclability are the advantages of the physical adsorption approach. In this work, an amine-functionalized hierarchical porous polymer was prepared by HIPE (high internal phase emulsions) template and amine impregnation strategy, and applied as CO₂ adsorbent to realize chemical adsorption and physical adsorption simultaneously. First, a hierarchical porous matrix of poly(styrene-glycidyl methacrylate) was prepared by the HIPE method. The formed meso/micropores in the typical porous polymer matrix could attract CO₂ molecules, where the physical adsorption was achieved. Subsequently, PEI (polyethyleneimine) was impregnated into the porous polymer with abundant macropores, and the numerous of amino groups provided the reaction sites, where the chemical adsorption was achieved. As a result, an effective CO₂ adsorption material was obtained via controlling the porous structure by changing the volume fraction of dispersive phase, impregnation condition and amine loading. Aided by the chemical adsorption of amino groups, the CO₂ adsorption capacity of the obtained adsorbent reached 3.029 mmol/g. Moreover, the CO₂ adsorption thermodynamics confirmed the physicochemical synergistic adsorption, and then the Q_st reduced to 31–42 kJ/mol and a good cyclic stability was obtained. As conclusion, the porous adsorbent showed a good industrial application prospect. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

In order to limit the increase in global average temperature to 1.5°C, it is necessary to reduce carbon dioxide (CO₂) emissions by 45% by 2030. CO₂ capture, utilization and storage (CCUS) is one of the effective ways to reduce CO₂ emissions. Geological storage of CO₂ provides a solution with the lowest economic cost and the fastest effect for reducing CO₂ emissions. This article proposes a CO₂ storage regional division method based on the characteristics of low-permeability reservoirs in the Yanchang W oilfield in China. The storage space is divided into four regions: gas phase region, two-phase or near-miscible region, diffusion region, and oil phase region. As the displacement progresses, the volume of the gas phase region and the two-phase or near-miscible region gradually increases; the volume of the diffusion region first increases and then decreases. By calculating the storage capacity of each region separately, the total storage capacity is finally calculated. The impact of different pressures and injection rates on dynamic CO₂ storage capacity was evaluated. The results show that pressure and injection rate are positively correlated with total storage capacity. When CO₂ miscible conditions are reached, the increase in total storage capacity will significantly decrease. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

With the increasing consumption of oil in the world and increasing production of oil from oil reservoirs, the reservoir pressure starts to decrease. On the other side, the use of oil leads to an increase in carbon dioxide production in the environment and causes global warming.

One of the effective methods of reducing the amount of carbon dioxide emitted into the atmosphere and increasing the reservoir's pressure is CO₂-EOR and carbon capturing and storing (CCS) which injects produced carbon dioxide from industrial sources into underground reservoirs. Carbon dioxide reduces oil viscosity and increases oil mobility producing an economical state. Moreover, with CO₂-EOR and CCS carbon dioxide can be stored in a depleted reservoir and helps reduce pollution and global warming.

Besides the environmental and economic benefits due to reducing carbon dioxide emissions to the atmosphere and increasing oil production, CO₂ injection causes various problems in the formation. Many experiments indicate that asphaltene precipitation and wettability alteration caused by asphaltene, dissolution/precipitation of rock, salt precipitation, and sludge formation are some of the problems that occur during CO₂ injection operations in low pressure and temperature. However, few experiments evaluate asphaltene precipitation effective factors, such as pressure, injection rates, temperature, etc., in high temperatures and pressure (HPHT) near reservoir conditions. Therefore, there was a need for a comprehensive investigation of various factors and the impact of each of them on the asphaltene precipitation and formation damage in HPHT conditions, so this research was designed to help future simulation and industrial utilization.

A core-flood setup was prepared to conduct CO₂ flooding experiments and formation damage studies in HPHT conditions. The main objective of this study was to evaluate the effect of different parameters including pressure, injection rate, and type of injected gas on asphaltene and its effect on formation damage caused by CO₂ injection. The second goal of this study was to investigate the optimum injection in every section. The third goal was to determine the oil recovery during the process of CO₂ injection in different conditions.

The results showed that an injection rate of 0.1 cc/min and higher injection pressures minimized asphaltene precipitation and maximized oil recovery. Replacing CO₂ with natural gas liquids (NGL) gas reduced oil production and asphaltene precipitation. Overall, the experiments demonstrated the importance of optimizing injection parameters to limit formation damage during CO₂ flooding. © 2024 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.

In this paper, the mechanisms of long-term CO₂ sequestration and the effects of injection modes (including injection temperature, injection rate and injection cycle) in Zhujiang Formation characterized by high porosity and permeability were investigated using the numerical simulation method. Simulation results showed that more than 88% of the injected CO₂ would exist in a supercritical state during the injection period and more than 79% of CO₂ would be sequestrated in the reservoir by mineral trapping after 5,000 years. Eventually, the distribution shape of SC-CO₂ was a quarter funnel near the injection well, while the distribution shapes of dissolved and mineralized CO₂ were both one quarter rotunda. During the long-term CO₂ sequestration in Zhujiang Formation, the dissolved minerals were anorthite, chlorite and smectite in turn, while the top three main precipitated minerals were calcite, dawsonite and albite. Moreover, higher injection temperature leads to a higher mineral tapping and more dissolved/precipitated minerals. While higher injection rate reduces the mineral tapping and total amount of dissolved/precipitated mineral. Compared to injection temperature and injection rate, the injection cycle has little effect on the CO₂ phase evolution and mineral dissolution/precipitation process. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

The research on the mechanism of coal and gas outburst is still in the hypothesis stage, and exploration of the outburst mechanism fro m an energy perspective often focuses on the calculation of coal rock elastic energy and gas expansion energy. There are some studies on elastic energy and gas expansion energy of coal rock caused by added water during outburst, although hydr aulic measures not only improve the permeability of coal seam, but also increase the water content. For calculating the gas expansion energy, the atmospheric gas desorption characteristic is generally utilized, while the gas desorption is completed on the condition of dropping pressure in outburst, and the expansion energy research, based on that law, inevitably brings about errors, thus affecting the objectivity of the potential research. In this study, uniaxial cyclic loading experiments were carried out on briquette coal samples with water content of 0%, 1%, 2% and 4%, whose elastic energy density was analyzed, in addition to examining how the added water affected the mechanical properties and the elastic energy of coal. The pressure drop gradient of the experiment is set 2.5 –2 MPa, 1.5 –1 MPa, 0.5 MPa-0 Pa. By stepwise depressurization desorption of coal samples after water injection, the gas expansion energy in different moisture is measured in each pressure drop stage, and the influence of moisture on gas expansion energy is quantitatively explored. Research has shown that the higher the water content, the lower the elastic energy density, while the higher the stress, the greater the elastic energy of coal. The gas expansion energy grows linearly with the increase of adsorption equilibrium pressure and diminishes in negative exponential law with the increasing moisture. Under the experimental conditions, the expansion energy decreases by 7%–9% and the elastic energy by 9.7% on average for every 1% increase in added water, and the influence gradually weakens when the moisture exceeds the critical value. This study innovatively simulates the pressure swing desorption when a coal and gas outburst occurs in the laboratory, confirms the critical moisture that affects the outburst potential, and is a useful exploration in the coal and gas outburst mechanism. Significantly the research results can guide the engineering practice when using hydraulic measures to prevent and control outburst disasters. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Anthropogenic activites release greenhouse gas emissions into our atmosphere, especially carbon dioxide (CO₂). This abundant accumulation of CO₂ generates numerous problems like global warming and climate change. However, research has been conducted to capture CO₂ from significant single-point emitters like compression ignition (CI) engines, backup generators, and distributed power production plants. Moreover, research has also been done on post-combustion adsorption chamber to capture CO₂ emissions from small stationary engines. Biomass-based activated carbon as an adsorbent for capturing CO₂ from engine exhaust has recently been investigated. Three biomass-based adsorbents, (a) coconut shell adsorbent, (b) rice husk adsorbent and (c) eucalyptus wood adsorbent, are used in the capture unit to trap CO₂ from the CI engine exhaust. This study uses a single-cylinder, four-stroke, air-cooled, naturally-aspirated, direct-injection (DI) CI engine running at a constant speed of 1,500 rpm and producing power of 4.4 kW. The adsorption performance of adsorbent samples is investigated by coupling the adsorption chamber to the exhaust system of a test engine operated on diesel (D100) at various loads. Temperature swing adsorption (TSA) is used to regenerate the original adsorbent. The adsorbents’ adsorption capacities are evaluated by performing multiple adsorption–desorption test cycles using the same adsorbents. During TSA, CO₂ released from the capture unit is further captured and stored in a gas bag. The captured gas sample is characterized through gas chromatography-mass spectroscopy (GC-MS) characterization to examine and ensure the gas adsorption efficacy of adsorbent samples. The outcomes of this research study are discussed and presented in detail. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Pipelines transporting impure supercritical carbon dioxide in the carbon capture, utilization, and storage (CCUS) chain exhibit varying decompression characteristics due to engineered emissions or accidental leakage, resulting in diverse temperature drops and heat transfer mechanisms in the media and pipe walls. Therefore, studying heat transfer characteristics during slow and instantaneous decompression is crucial to investigating pipeline operational risks. In this work, supercritical CO₂ pipeline valve release and rupture disc release experiments were performed with a 1.5% molar ratio of N₂ content in an experimental pipeline (16 m long, 100 mm inner diameter). The evolution of the medium and pipe wall's physical properties was measured and discussed. Two methods of depressurization were employed to analyze the phase changes and heat transfer processes in the pipe. The instantaneous decompression process has a shorter decompression time and undergoes fluctuating and stable decompression stages. The slow decompression process has a slower temperature drop rate, but the wall during the process can reach a lower minimum temperature. Both release methods cause a larger temperature drop and Nusselt number at the bottom of the pipe wall due to evaporation heat transfer compared to the middle and top. The slow decompression process demonstrates a higher peak Nusselt number at the bottom, resulting in superior heat transfer efficiency compared to the instantaneous decompression process. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

The present work investigated the effects of some non-condensable impurities (i.e., N₂, O₂, CH₄, and Ar) on the phase behaviour of CO₂-rich systems at low temperature conditions (228.15–273.15 K). The study focused on bubble point measurements of CO₂-rich systems using the isothermal (pressure–volume) method at different mole fractions of CO₂ (99.5%–95%). The obtained experimental data were used to validate multi-fluid Helmholtz energy approximation (MFHEA) and Peng–Robinson (PR) equations of state (EoSs). For all data points, the measurements’ uncertainties for temperature and pressure were 0.14 K and 0.03 MPa, respectively. While the composition uncertainty of the CO₂ systems was a maximum of 0.024%. The findings reveal that as the mole fractions of the impurities increased, the bubble point pressures of the binary mixtures were elevated. Among all the investigated impurities, N₂ has the most significant effect on the bubble point pressures of CO₂ binary mixture at all the isotherms and compositions. Both MFHEA and PR models agreed well with the measured equilibrium points. For all systems, the average absolute deviations of the measured experimental data against the MFHEA and PR EoSs, were found to be less than 3.4% and 2.2%, respectively. Although the MFHEA EoS overpredicted most of the data points, the overall trend agreed with the experimental data and was consistent with the data available in the literature. The findings imply that the presence of these non-condensable impurities (even as low as 0.5% mole fraction) increases the risk of two-phase flow at higher pressures in a CO₂-rich system. © 2023 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.