Search Results (155)

Main engine load varies continuously, whereas onboard carbon capture columns are installed with fixed capacities. For liquefied natural gas (LNG)-fueled ships, this mismatch between design and operation makes off-design robustness, rather than nominal-point performance, the governing sizing criterion. This study developed a variable-load design window for onboard monoethanolamine CO₂ capture and evaluated a dual-loop organic Rankine cycle (ORC) as a secondary thermal integration option. A verified process model was applied to a 5 × 5 design–operating matrix (D50–D90/O50–O90). The mismatch was strongly asymmetric. When operating load did not exceed design load, capture rate remained near 90%; under overload, absorber treated only the design-point-equivalent exhaust-gas flow, causing capture performance to deteriorate rapidly. The mean CO₂ avoided rate increased from 57.4% at D50 to 70.4% at D90, while absorber diameter increased from 3.23 to 4.06 m. D70 emerged as the balanced option for low- to medium-load services, D80 marked the transition before full robustness, and D90 was robustness-oriented for frequent high-load operation. The ORC recovered 104–185 kW net power and supplied 231–410 kW LNG-side heating. Results support capacity selection before ORC application; CO₂ liquefaction and storage, voyage-weighted validation, and shipboard ORC feasibility remain outside the present scope. Full article

Carbon taxes and credits (CT&C) accelerate global deployment of carbon capture, utilization and storage (CCUS) technologies to enable energy transition. This study investigates the economic performance and resilience of floating gas-to-wire with CCUS (f-GTW-CCUS), deployed at the wellhead of stranded CO₂-rich offshore oil and gas reservoirs. The f-GTW-CCUS platform integrates a natural gas combined cycle power plant with monoethanolamine post-combustion capture (PCC-MEA), producing low-carbon electricity (23 kgCO_2e/MWh, competitive with renewables) while monetizing captured CO₂ via enhanced oil recovery (EOR). The mass and energy balance data from the proposed process configuration were obtained in the literature. Critically, f-GTW-CCUS operates on wellhead-sourced in situ-associated gas, eliminating exposure to volatile natural gas markets, and achieves a levelized cost of electricity (LCOE) of USD 67.15/MWh. Monte Carlo analysis (10,000 Gaussian iterations, 30-year lifetime, 10% discount rate, three CT&C scenarios, namely, low/medium/high) is used to quantify economic feasibility across three stochastic variables: oil, natural gas, and electricity prices, starting in the 5th year. The results demonstrate the following: (1) Case A (f-GTW without CCUS) remains economically infeasible (NPV < 0) under all price volatility scenarios due to insufficient electricity-only revenue and carbon taxation penalties; (2) Case B (f-GTW-CCUS with immediate CCUS deployment) maintains positive NPV across all scenarios, with EOR monetization contributing 43% of total revenue; (3) the critical CCUS deployment-delay threshold is 6 years under high carbon taxation, extending to 10 years when carbon credits are included. Gate-to-gate environmental assessment (carbon intensity, water footprint, land transformation) shows f-GTW-CCUS superiority versus alternative power systems, with minimal water–land nexuses due to offshore desalination. An empirical consistency assessment based on the 2026 geopolitical energy crisis demonstrates the structural resilience of the f-GTW-CCUS plant: the wellhead sourcing provides resilience to global natural gas price shocks, while the concurrent crude price escalation amplifies EOR revenues by 43–57%, improving project feasibility during commodity disruptions. These findings position f-GTW-CCUS as a critical decarbonization pathway for O&G producers exploiting stranded gas reserves. The technology combines carbon intensity reduction with economic resilience under volatile energy market conditions and mandatory climate policies. Full article

Against the backdrop of the global energy transition and decarbonization imperative targets, improving the efficiency of conventional energy systems while simultaneously reducing carbon emissions has become a pressing challenge. To address the widespread problem of insufficient waste heat utilization in combined cooling, heating, and power (CCHP) systems, this study proposes a novel low-carbon-emission CCHP system coupled with heat pump (HP) technology and a monoethanolamine (MEA)-based carbon capture and storage (CCS) subsystem. The HP unit enables cascaded recovery and temperature upgrading of low-grade waste heat from both the flue gas and the CCS regeneration column. A comprehensive five-dimensional evaluation framework—covering energy, exergy, life cycle environmental assessment, economic and exergoeconomic analyses—is established and benchmarked against a conventional low-carbon CCHP reference system. Thermodynamic results show that HP integration raises the overall energy efficiency from 74.25% to 81.22% and the waste heat recovery rate from 73.59% to 89.85%, while simultaneously reducing exergy losses by 365.06 kW and elevating exergy efficiency from 53.95% to 65.07%. Economic analysis reveals that the unit energy production cost decreases from 0.033 to 0.031 $/(kW·h), despite a marginal increase in unit power generation cost. Sensitivity analysis identifies operating hours and interest rate as the dominant cost drivers. Exergoeconomic analysis pinpoints the turbine, the CCS subsystem, and the compressor as contributing 67.02%, 17.11%, and 8.17% of the total exergoeconomic losses, respectively, identifying them as the primary targets for future optimization. These findings provide a theoretical foundation and engineering guidance for the development and deployment of high-efficiency, low-carbon multi-generation energy systems. Full article

Among the various CO₂ capture technologies, chemical absorption is currently one of the most widely applied methods in industrial practice. In this study, density functional theory was employed to investigate the reaction mechanisms of CO₂ absorption by typical alkanolamine solvents. Reaction pathways between CO₂ and four representative alkanolamines—monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and methyldiethanolamine (MDEA)—were constructed and analyzed. By evaluating the activation energy barriers of different amines, the thermodynamic characteristics and reaction feasibility of the CO₂ absorption process were systematically elucidated. The results show that the primary amine MEA exhibits the lowest activation energy barrier (32.02 kJ/mol), indicating the most favorable reaction kinetics, while the secondary amine DEA shows a slightly higher barrier of 47.35 kJ/mol. As tertiary amines, TEA and MDEA exhibit significantly higher activation energy barriers, indicating slower reaction kinetics; however, they generally possess higher CO₂ loading capacities and less stable reaction products, which facilitate solvent regeneration. The activation energy barriers of MDEA and TEA were calculated to be 54.53 kJ/mol and 94.17 kJ/mol, respectively, indicating that MDEA reacts more readily with CO₂ than TEA. Full article

The post-combustion carbon capture process with monoethanolamine/piperazine (MEA/PZ) blends encounters notable modeling and optimization challenges. These arise from strong thermodynamic–kinetic nonlinear coupling, as well as limited availability of high-quality experimental data. To address this, we propose a machine learning and multi-objective optimization strategy driven by physicochemical features. By extracting explicit physical features and embedding physicochemical constraints into data-driven models, this study evaluated the predictive performance of three distinct algorithms based on wet-wall column experimental data. These algorithms included natural gradient boosting (NGBoost), sure independence screening and sparsifying operator (SISSO), and gaussian process regression (GPR). Subsequently, an optimization problem aimed at minimizing $P_{{\mathrm{CO}}_2}^{*}$ and maximizing $k_{\mathrm{g}}^{\prime }$ was formulated. The multi-objective beluga whale optimization (MOBWO) algorithm was then employed for global optimization and benchmarked against the traditional non-dominated sorting genetic algorithm II (NSGA-II). Results indicate that the Gaussian process regression (GPR) model performed best when it was enhanced by physicochemical features and optimized via Bayesian hyperparameter tuning. It achieved R² values of 0.989 and 0.953 for $P_{{\mathrm{CO}}_2}^{*}$ and $k_{\mathrm{g}}^{\prime }$, with average absolute relative deviations (AARDs) kept below 15.7% and 12.2% respectively. Feature importance analysis validated the underlying physical laws. Specifically, temperature dictates thermodynamic equilibrium, while CO₂ loading limits mass transfer kinetics. In the optimization phase, MOBWO outperformed NSGA-II by generating a more uniformly distributed Pareto front. Decision-making analysis further identified three typical operating regimes encompassing kinetics-dominant, thermodynamics-dominant, and comprehensive equilibrium conditions. This framework provides a robust paradigm for small-sample modeling and optimization in complex chemical processes. Full article

Efficient pretreatment is essential for improving the conversion of lignocellulose into fermentable sugars and bioethanol. In this study, choline chloride–monoethanolamine (ChCl-MEA)-based solvent systems containing H₂O₂, NaHCO₃, Na₂S, or ethylene glycol were prepared and applied for the pretreatment of Dendrocalamus brandisii. Among the tested systems, ChCl-MEA-Na₂S showed the best overall pretreatment performance, achieving 92.8 ± 2.3% delignification and 86.1 ± 1.7% cellulose retention. It also effectively disrupted lignin–carbohydrate associations, reduced lignin shielding and generated a more accessible cellulose-rich substrate for bioconversion. In the following separation enzymatic hydrolysis and fermentation, 92.2 ± 2.2% cellulose in substrate was converted to glucose, and 17.49 ± 0.7 g/L ethanol was obtained via the fermentation of enzymatic hydrolysate. Taking the bioconversion of substrate into consideration, the ChCl-MEA-H₂O₂ and ChCl-MEA-Na₂S were recovered for full component utilization. Especially, the carbon dots produced from the degradation compounds in ChCl-MEA-H₂O₂ DESs had favorable antioxidation and antibacterial performance due to the oxygen-containing group caused by oxidation of H₂O₂. Full article

Rapid urbanization and escalating demands for pollution and carbon reduction pose significant challenges to the cement industry in China, characterized by high energy consumption and emissions. However, a multidimensional framework to assess the synergies and trade-offs between environmental, carbon, and economic effects for various decarbonization technologies in cement production is still lacking. Here, six application scenarios of new suspension preheater dry process cement production were developed and evaluated using a life cycle assessment (LCA) framework to quantify environmental impacts, synergistic reduction of pollution and carbon emissions (SRPC), and economic performance. A multi-attribute decision-making model, Analytic Hierarchy Process–entropy–TOPSIS (AHP–entropy–TOPSIS), was applied to assess environmental–economic trade-offs. The results indicate that biomass fuel substitution and high grinding efficiency achieved the best SRPC and environmental–economic trade-off scores (S_norm: 0.17–0.22). Alternative raw materials moderately reduced carbon but increased pollutant emissions and economic uncertainty (S_norm: 0.14–0.20). Mono-ethanolamine absorption and calcium looping provided substantial carbon reduction but weaker overall performance due to environmental trade-offs and higher costs (S_norm: 0.12–0.16). These findings provide quantitative guidance for prioritizing and combining decarbonization strategies to support the green transition and sustainable development of the cement industry. Full article

Monoethanolamine (MEA) remains the predominant solvent for carbon dioxide (CO₂) capture due to its rapid reaction kinetics, substantial absorption capacity, and demonstrated industrial effectiveness. Despite its established status, MEA-based systems are undergoing continuous development to lower energy requirements, enhance solvent stability, and expand operational adaptability. This review provides a critical assessment of recent progress in MEA-based CO₂ capture, encompassing molecular-level understanding, advancements in reactor and process design, solvent modification strategies, and system-wide optimization. Recent theoretical and experimental research has improved the understanding of CO₂ absorption mechanisms in MEA, highlighting the effects of reaction-product buildup, interfacial phenomena, and free amine availability on mass-transfer efficiency. Reboiler duty and comparable work have significantly decreased as a result of advances in process intensification, improved regeneration systems, and energy-integration techniques. New hybrid strategies that partially decouple capture from thermal regeneration, such as combined absorption–mineralization pathways, show promise for long-term CO₂ sequestration. To address regeneration energy, corrosion, degradation, and cyclic stability, this review examines advances in MEA-based solvents, including aqueous blends, non-aqueous and biphasic systems, ionic liquids, and deep eutectic solvent hybrids. It also critically assesses the trade-offs of developments in intensified contactors, surfactants, nanomaterials, and catalysts. The growing role of digital optimization, machine learning, and computational modeling in MEA process design and control is highlighted. Overall, this analysis underscores MEA’s continued importance as a versatile platform for next-generation carbon capture, utilization, and storage. Full article

One-dimensional mass transfer resistance-in-series framework was developed theoretically and validated experimentally using a flat-plate polytetrafluoroethylene/polypropylene (PTFE/PP) membrane module to predict CO₂ absorption fluxes and concentration distributions. The decline in CO₂ absorption efficiency along the membrane module is primarily attributed to increased concentration polarization resistance and a reduced driving force concentration gradient. To alleviate these limitations, carbon fiber promoters were strategically embedded to suppress concentration polarization, reduce the mass transfer resistances, and enhance turbulence intensity. In the present study, device performance was further improved by implementing properly ascending or descending hydraulic equivalent widths along the absorbent feed channel. Under the descending configuration, an absorption flux enhancement of up to 44.94% was achieved relative to an empty-channel module (i.e., without S-ribbed carbon fiber inserts). Theoretical formulations were established to predict absorption fluxes under varying monoethanolamine (MEA) volumetric flow rates, CO₂/N₂ mixture flow rates, and inlet CO₂ feed concentrations. The model predictions showed good agreement with experimental results obtained using MEA solutions under both ascending and descending hydraulic width operations, demonstrating effective mitigation of polarization effects and enhanced absorption flux along the absorbent feed channel. An economic assessment of the S-ribbed carbon fiber module was conducted by evaluating the trade-off between absorption flux enhancement and incremental power consumption. The results indicate that the proposed design provides a practical and economically viable approach for improving the performance of membrane-based CO₂ capture technologies. In addition, an enhanced Sherwood number correlation, expressed in a simplified form, was developed and employed to estimate the mass transfer coefficients of CO₂ membrane absorption modules incorporating S-ribbed carbon fiber promoters. Full article

Although amine-based post-combustion carbon capture is among the most established routes for CO₂ capture, it suffers from the high energy demand associated with amine regeneration. Recent research proposals suggest that microwave or frequency-tuned infrared heating may lead to more efficient amine regeneration processes. However, such approaches inherently introduce oscillating electromagnetic fields whose non-thermal effects on reaction pathways and energetics remain poorly understood. In this series paper, we employ high-accuracy quantum computational chemistry calculations to quantify the non-thermal effects of external electric fields on CO₂ absorption and desorption in monoethanolamine (MEA) and triethanolamine (TEA) under both aqueous and non-aqueous conditions. In this first part, we focus on static electric fields in order to establish a mechanistic reference framework helpful for interpreting non-thermal effects arising from frequency-tuned infrared laser excitation, which are addressed in Part II of this series. Our results show that static electric fields stabilize CO₂–amine reaction products, lowering absorption barriers, while consistently increasing both activation energies and reaction enthalpies associated with the amine regeneration process. This effect is particularly pronounced for MEA, where carbamate species become progressively more resistant to conversion to zwitterion as the field strength increases. These findings demonstrate that non-thermal static electric field effects counter the fundamental requirement for low-energy amine regeneration. By defining this intrinsic mechanistic limitation, the present study provides a useful baseline for assessing infrared laser-assisted carbon capture and underscores the importance of carefully selecting excitation frequencies to avoid adverse non-thermal stabilization effects. Full article

Carbon dioxide (CO₂) capture is a cornerstone of global carbon neutrality, yet the high energy penalty associated with solvent regeneration—particularly for monoethanolamine (MEA) systems—remains a major barrier to its sustainable deployment. This study presents a sustainable and high-performance catalytic solution using micro-sized iron oxyhydroxide (β-FeOOH). Characterized by a high specific surface area ($287 m²/g) and a synergistic distribution of abundant Lewis and Brønsted acid sites, the β-FeOOH catalyst significantly enhances CO₂ desorption kinetics. Experimental results demonstrate that the incorporation of β-FeOOH into a 30 wt% MEA solution increases the CO₂ desorption rate by 10.9% while simultaneously lowering the regeneration temperature from the conventional 120 °C to 85 °C. Such a reduction in thermal requirements offers a pathway to utilize low-grade industrial waste heat, drastically improving the process’s energy efficiency. Furthermore, the catalyst exhibited remarkable cyclic stability over ten consecutive cycles, maintaining its structural integrity and catalytic activity. These findings highlight β-FeOOH as an eco-friendly, cost-effective, and robust catalyst that aligns with the principles of green chemical engineering, offering a scalable strategy to enhance the sustainability of carbon capture operations. Full article

Post-combustion amine scrubbing using monoethanolamine (MEA) remains a leading carbon capture technology, yet its deployment is constrained by high regeneration energy requirements and the computational expense of rigorous process simulation. This study presents an integrated framework coupling high-fidelity rate-based process simulation with explainable machine learning to systematically characterize a ten-dimensional operating space for MEA-based CO₂ absorption. Latin hypercube sampling generated 10,000 steady-state cases, and five regression architectures were benchmarked under identical protocols. A neural network achieved the highest accuracy (R² = 0.9729, RMSE = 1.43%), while XGBoost was selected as the operational surrogate due to its robust computational efficiency (1.5 ms inference latency) and native compatibility with exact Shapley value decomposition. SHAP analysis identified liquid-to-gas ratio as the dominant efficiency determinant, contributing 46.6% of total predictive importance, followed by inlet temperature and MEA concentration, with these three parameters collectively explaining 85% of efficiency variation and establishing a compact control hierarchy suitable for reduced-order control architectures. Bivariate interaction analysis located a high-efficiency operating region, while sensitivity analysis confirmed the strong influence of inlet temperature across the operating envelope. Pareto optimization via NSGA-II generated tiered operational guidelines spanning the 85% to 98% capture efficiency range, quantifying a 39% specific regeneration duty penalty (3.1 to 4.3 MJ/kg CO₂) for pursuing maximum versus baseline capture targets. The framework demonstrates how explainable machine learning converts opaque process simulations into actionable engineering knowledge, providing a transparent and computationally efficient basis for design optimization and digital twin deployment in post-combustion carbon capture systems. Full article

The release of CO₂ gas into the atmosphere is one of the most prolific causes of global climate change. To solve this problem, cost-effective technologies are being sought. Polymer membranes are innovative materials that can be widely used in the process of capturing and separating CO₂ gas. In this work, an amine impregnated and amidated solid sorbent (AISS) containing a copolymer (PMMA-co-AA), which consists of acrylic acid (AA) and methyl methacrylate (MMA), and PEPA (polyethylene polyamine), was synthesized. For the first time, sorbents based on homopolymers and copolymers of acrylic acid and methyl methacrylate were compared for their ability to capture CO₂ gas. Other than the synthesis of low swelling AISS, a calculation of its energy consumption, and a comparison of its cyclic capacity with 30% water solutions of monoethanolamine and methyldiethanolamine (MEA and MDEA) were performed. The solid sorbent PMMA-co-AAS showed a higher cyclic capacity than others, corresponding to the order PMMA-co-AAS (23 mg/g) > PAAS (16 mg/g) > MDEA (10 mg/g) > MEA (6 mg/g). The average absorption rate for these sorbents was in the sequence of MEA > PMMA-co-AAS > PAAS > MDEA at 40 °C, and the desorption rates were PMMA-co-AAS > PAAS > MDEA > MEA for these sorbents at 70 °C, correspondingly. When the amount of acrylic acid in the copolymer was varied from 0 to 100%, the copolymer’s water absorption capacity ranged from 0.2 to 1359.63%. Among them, the swelling ability of the chosen sorbent prepared from the 10% AA-containing copolymer and PEPA was 0.64%. Full article

Development of green and efficient technologies for valorizing crayfish shell waste is crucial for enhancing industrial value. This study presents an integrated strategy for the extraction and structural engineering of chitin using a novel alkaline deep eutectic solvent (DES) system composed of lysine and monoethanolamine (LysMEA), which enables the simultaneous deproteinization and architectural modification of chitin. Following mild demineralization, the optimized process yielded chitin with 97.1% purity and a high molecular weight of 209.3 kDa. DES demonstrated considerable reusability and decolorization capability. Structural characterization revealed that the LysMEA system effectively engineered the chitin architecture, resulting in lower crystallinity and a larger surface area compared to conventional methods. This engineered structure rendered the chitin highly accessible to enzymes. Consequently, the chitin extracted by LysMEA exhibited superior reactivity, achieving a deacetylation degree of 63.7% when catalyzed by Bacillus aryabhattai chitin deacetylase, significantly outperforming chitin obtained via acid-alkali or acidic DES methods. Molecular dynamics simulations elucidated the mechanism, showing that lysine and monoethanolamine molecules penetrated the chitin fiber bundles at high temperatures, weakening interchain hydrogen bonds and partially separating the chains. This work provides a green route for producing enzymatically reactive chitin, demonstrating the potential of solvent-based structural engineering in biocatalytic valorization. Full article

The recycling of carbon fiber-reinforced polymers (CFRPs), particularly carbon fiber-reinforced epoxy polymers (CFREPs), is a challenging problem because of their broad application spectrum, the amount of laminates produced per year, and the cost per kg of the carbon fiber fabric. Recently, several papers were published on the recycling of CFREPs through solvothermal methods that allow the recovery of the carbon fiber fabrics with a relatively low environmental impact. In the present paper, for the first time, the effect of the presence of flame retardants is discussed. A carbon fiber-reinforced epoxy polymer (CFREP) charged with P-, Zn-, B- and Al-based flame retardants, supplied by the aerospace industry, was subjected to a double-step solvothermal treatment. The epoxy matrix was successfully dissolved in monoethanolammine after a preswelling step in acetic acid. The experimental results show that the proposed process allows the full recovery of the carbon fabric with its original sizing layer without injury to the fiber. As confirmation, CFREP laminates produced with the recycled carbon fiber fabrics exhibited mechanical properties close to that of laminates obtained from the virgin epoxy/carbon prepreg. Contrary to what is reported in the literature, the present paper also shows that, in the studied case, whilst acetic acid treatment promotes swelling, it also causes the formation of a degraded surface layer that would impede complete removal of the polymeric matrix and full recovery of the carbon fabric if only acetic acid was used. On the basis of the known mechanism of flame retardancy of phosphates and borates, the degraded layer formation is attributed to the acidic character of the acetic acid. It is worth pointing out that the paper suggests, therefore, that the presence of flame retardants may strongly affect the solvothermal processes. Full article