A comprehensive computational fluid dynamics（CFD） model is developed based on the gas-liquid two-phase hydrodynamics,gas-liquid mass-transfer theory and chemical reaction kinetics,and the ammonia-based CO2 absorptio...A comprehensive computational fluid dynamics（CFD） model is developed based on the gas-liquid two-phase hydrodynamics,gas-liquid mass-transfer theory and chemical reaction kinetics,and the ammonia-based CO2 absorption in a spray column is numerically studied.The Euler-Lagrange model is applied to describe the behavior of gas-liquid twophase flowand heat transfer.The dual-film theory and related correlations are adopted to model the gas-liquid mass transfer and chemical absorption process.The volatilization model of multi-component droplet is utilized to account for ammonia slippage.The effect of operation parameters on CO2 removal efficiency is numerically studied.The results showa good agreement with the previous experimental data,proving the validity of the proposed model.The profile studies of gasphase velocity and CO2 concentration suggest that the flowfield has a significant impact on the CO2 concentration field.Also,the local CO2 absorption rate is influenced by both local turbulence and the local liquid-gas ratio.Furthermore,the velocity field of gas phase is optimized by the method of adjusting the orifice plate,and the results showthat the CO2 removal efficiency is improved by approximately 4%.展开更多
Phase change solvents are attractive energy-efficient absorbents for carbon dioxide(CO_2) capture due to CO_2-rich phase formation. Potassium prolinate + water + ethanol(ProK/W/Eth) solution has shown good capture cha...Phase change solvents are attractive energy-efficient absorbents for carbon dioxide(CO_2) capture due to CO_2-rich phase formation. Potassium prolinate + water + ethanol(ProK/W/Eth) solution has shown good capture characteristics as a promising one in our previous work. In this work, absorption rate of CO_2, solubility of N2 O,and heat of absorption for ProK/W/Eth solution were investigated using a stirred cell reactor and a CPA201 reaction calorimeter and these results were also compared with the aqueous ProK and 30 mass% MEA solutions.Using ethanol as a solvent can substantially increase the CO_2 physical solubility and the absorption rate of CO_2 in ProK/W/Eth solutions is far higher than that in aqueous 30 mass% MEA solutions especially at a low CO_2 loading range. Solid precipitation, obtained from the liquid-to-solid phase change absorption, was analyzed by13 C NMR and DSC-TGA. The enthalpy change for ProK/W/Eth solutions at various CO_2 loading was also discussed.展开更多
Aqueous 1,8-diamino-p-menthane （KIER-C3） and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol （AMP） solution with an addition of KIER-C3 showed 9.3% and 31.6% hi...Aqueous 1,8-diamino-p-menthane （KIER-C3） and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol （AMP） solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine （MEA） and ammonia （NH3）, respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation： k2,AMP/C3 = 7.702×106 exp （-2248.03/T）. A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.展开更多
Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures ...Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures were prepared through digital light processing(DLP)3D printing,polymer-derived ceramics(PDCs),chemical vapor infiltration(CVI),and oxidation technologies.The incorporation of the CVISiC phase effectively increases the dissipation capability,while the synergistic interaction between the gyroid structure and SiO_(2)phase significantly improves impedance matching performance.The SiOC/SiC/SiO_(2)composite achieved a minimum reflection loss(RL min)of-62.2 d B at 4.3 mm,and the effective absorption bandwidth(EAB)covered the X-band,with a thickness range of 4.1 mm-4.65 mm.The CST simulation results explain the broadband and low-frequency absorption characteristics,with an EAB of 8.4 GHz(9.6-18 GHz)and an RL min of-21.5 dB at 5 GHz.The excellent EM wave attenuation performance is associated primarily with polarization loss,conduction loss,the gyroid structure's enhancement of multiple reflections and scattering of EM waves,and the resonance effect between the structural units.The SiOC/SiC/SiO_(2)composite also demonstrated strong mechanical properties,with a maximum compressive failure strength of 31.6 MPa in the height direction.This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties.展开更多
The carbon dioxide （CO2） removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine （MEA） ＋ 2-amino-2-methyl-l-propanol （AMP） solutions to enhance absorption characteristics of MEA...The carbon dioxide （CO2） removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine （MEA） ＋ 2-amino-2-methyl-l-propanol （AMP） solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA ＋ AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA ＋ 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA （0.41 mol CO2/mol amine）. Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.展开更多
Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at...Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L^(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L^(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.展开更多
A dual-gas sensor system is developed for CO and CO_2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing(TDM) technique. A stepper motor based rotating system and a ...A dual-gas sensor system is developed for CO and CO_2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing(TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode(without rotation) and dynamic mode(with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million(ppm) in volume and 2.6 ppm for CO and CO_2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO_2, respectively. The reported sensor has potential applications in various fields requiring CO and CO_2 detection such as in the coal mine.展开更多
Carbon dioxide （CO2） removal is an essential step in natural gas （NG） processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study alms to investigate the re...Carbon dioxide （CO2） removal is an essential step in natural gas （NG） processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study alms to investigate the removal of CO2 at high concentration level from the mixture of CO2-NG gas stream at elevated pressure via absorption process. This is to explore the possibility of exploring high CO2 content natural gas reserves by treatment at offshore platform. A mixed amine solvent, Stonvent-II, was used for the absorption of approximately 75 vol% CO2 in CO2-NG stream at a pressure of 10 barg. The initial solvent temperature was varied in order to study the impact of initial temperature on the absorption performance. Preliminary study at temperatures of 35 ℃ and 45 ℃ indicates that Stonvent-II was able to perform almost 100% removal of CO2 under both conditions. However, the CO2 absorption effect took place faster when the initial liquid temperature was lower. This is because when the initial liquid temperature is high, the temperature increase in the packing bed caused by the reaction heat is high which impacts the efficiency of absorption negatively.展开更多
The paper presents an energy performance assessment of CO2 removal for crude synthetic natural gas （SNG） upgrade by Selexol absorption process. A simplified process simulation of the Selexol process concerning power...The paper presents an energy performance assessment of CO2 removal for crude synthetic natural gas （SNG） upgrade by Selexol absorption process. A simplified process simulation of the Selexol process concerning power requirement and separation performance was developed. The assessment indicates that less pressure difference between crude SNG and absorption pressure favors the energy performance of CO2 removal process. When both crude SNG and absorption pressures are 20 bar, CO2 removal process has the best energy performance. The optimal specific power consumption of the CO2 removal process is 566 kJ/kgCO2. The sensitivity analysis shows that the CO2 removal efficiency would significantly influence the total power consumption of the removal process, as well as higher heating value （HHV） and CO2 content in SNG. However, the specific power consumption excluding crude SNG and SNG compressions changes little with the variance of CO2 removal efficiency. If by-product CO2 is compressed for CO2 capture, the process would turn into a CO2-sink for the atmosphere. Correspondingly, an increase of 281 kJ/kgCO2 in specific power consumption is required for compressing the separated CO2.展开更多
At present monoethanolamine(MEA) remains as the standard industrial solvent for CO_2 capture processes. But due to the degradation and high energy consumption problems of MEA, new efficient solvents should be found. I...At present monoethanolamine(MEA) remains as the standard industrial solvent for CO_2 capture processes. But due to the degradation and high energy consumption problems of MEA, new efficient solvents should be found. In the present work, the absorption and regeneration performance of a hybrid solvent MEA-methanol was studied and compared to the aqueous solutions of monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA) in a bubbling reactor. Also the performance of MEA-methanol solutions(including the absorption performance, regeneration performance,cyclic absorption performance, density and viscosity) was studied with different MEA concentrations. A pilot-plant CO_2 capture test bed was used to study the potential of MEA-methanol to replace aqueous MEA in industrial use. The results showed that the initial absorption rate of MEA-methanol solvent is the fastest compared with other solvents. The 30% MEA-methanol had a faster mass transfer coefficient, a higher CO_2 absorption efficiency and a lower regeneration energy consumption than aqueous MEA. And through the study of the reaction heat of CO_2 into MEA-methanol and aqueous MEA,it can be concluded that the desorption heat of rich MEA-methanol is only about 30% of rich aqueous MEA solvent in the regeneration process which showed that 30% MEA-methanol solvent is a promising candidate for CO_2 capture.展开更多
Exploring high-efficiency and broadband microwave absorption(MA)materials with corrosion resistance and low cost is ur-gently needed for wide practical applications.Herein,the natural porous attapulgite(ATP)nanorods e...Exploring high-efficiency and broadband microwave absorption(MA)materials with corrosion resistance and low cost is ur-gently needed for wide practical applications.Herein,the natural porous attapulgite(ATP)nanorods embedded with TiO_(2)and polyaniline(PANI)nanoparticles are synthesized via heterogeneous precipitation and in-situ polymerization.The obtained PANI-TiO_(2)-ATP one-di-mensional(1D)nanostructures can intertwine into three-dimensional(3D)conductive network,which favors energy dissipation.The min-imum reflection loss(RL_(min))of the PANI-TiO_(2)-ATP coating(20wt%)reaches-49.36 dB at 9.53 GHz,and the effective absorption band-width(EAB)can reach 6.53 GHz with a thickness of 2.1 mm.The excellent MA properties are attributed to interfacial polarization,mul-tiple loss mechanisms,and good impedance matching induced by the synergistic effect of PANI-TiO_(2)nanoparticle shells and ATP nanor-ods.In addition,salt spray and Tafel polarization curve tests reveal that the PANI-TiO_(2)-ATP coating shows outstanding corrosion resist-ance performance.This study provides a low-cost and high-efficiency strategy for constructing 1D nanonetwork composites for MA and corrosion resistance applications using natural porous ATP nanorods as carriers.展开更多
The preparation of electromagnetic(EM)wave absorption materials provided with the characteristics of thin matching thickness,broad bandwidth,and mighty absorption intensity is an efficient solution to current EM pollu...The preparation of electromagnetic(EM)wave absorption materials provided with the characteristics of thin matching thickness,broad bandwidth,and mighty absorption intensity is an efficient solution to current EM pollution.Herein,Graphene nanosheets(GN)were firstly fabricated via a facile high-energy ball milling method,subsequently high-purity 1T-MoS_(2) petals were uniformly anchored on the surface of GN to prepare 1T-MoS_(2)@GN nanocomposites.Plentiful multiple reflection and scattering of EM waves in a distinctive multidimensional structure formed by GN and 1T-MoS_(2),copious polarization loss consisting of interfacial polarization loss and dipolar polarization loss severally derived from multitudinous heterointerfaces and profuse electric dipoles in 1T-MoS_(2)@GN,and mighty conduction loss originated from plentiful induced current in 1T-MoS_(2)@GN generated via the migration of massive electrons,all of which endowed 1T-MoS_(2)@GN nanocomposites with exceptional EM wave absorption performances.The minimum reflection loss(RLmin)of 1T-MoS_(2)@GN reached–50.14 dB at a thickness of only 2.10 mm,and the effective absorption bandwidth(EAB)was up to 6.72 GHz at an ultra-thin matching thickness of 1.84 mm.Moreover,the radar scattering cross section(RCS)reduction value of 36.18 dB m2 at 0°could be achieved as well,which ulteriorly validated the tremendous potential of 1T-MoS_(2)@GN nanocomposites in practical applications.展开更多
Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_...Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_(4)/residual carbon from coal gasification fine slag(CFO/RC)composites were created using a novel hydrothermal method.Various mechanisms for microwave absorption,including conductive loss,natural resonance,interfacial dipole polarization,and magnetic flux loss,are involved in these composites.Consequently,compared with pure residual carbon materials,this composite offers superior capabilities in microwave absorption.At 7.76GHz,the CFO/RC-2 composite achieves an impressive minimum reflection loss(RL_(min))of-43.99 dB with a thickness of 2.44 mm.Moreover,CFO/RC-3 demonstrates an effective absorption bandwidth(EAB)of up to 4.16 GHz,accompanied by a thickness of 1.18mm.This study revealed the remarkable capability of the composite to diminish electromagnetic waves,providing a new generation method for microwave absorbing materials of superior quality.展开更多
The single-layer Ti_(3)C_(2)T_(x)/MXene has become a special electromagnetic wave absorber near the terahertz band because of its abundant surface groups and excellent conductivity.However,the macro-preparation of sin...The single-layer Ti_(3)C_(2)T_(x)/MXene has become a special electromagnetic wave absorber near the terahertz band because of its abundant surface groups and excellent conductivity.However,the macro-preparation of single-layer Ti_(3)C_(2)T_(x)/MXene shows significantly difficult to influence its application.The two-dimensional Ti_(3)C_(2)T_(x)is easily prepared to have high production,but its weak absorption ability due to high surface conductivity also restricts its application.To realize the strong electromagnetic wave absorption of two-dimensional Ti_(3)C_(2)T_(x)/MXene,a new strategy with magnetic FeNi nanoparticles decorating Ti_(3)C_(2)T_(x)/MXene composites(FeNi-Ti_(3)C_(2)T_(x))were proposed and the effective electromagnetic wave absorption features covering 170-220 GHz that means the absorption band width reach 50 GHz.With an absorber composite film thickness being only 0.6 mm,the absorptivity of the composite is enhanced with the increase of decorating FeNi nanoparticles and promote up to 75%when the FeNi nanoparticles loading content reaches 30 wt%.The improvement of absorption is attributed to the introduction of soft magnetic FeNi to adjust the high surface conductivity of MXene and improve the electromagnetic balance of the absorber.展开更多
Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship betw...Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.展开更多
As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires com...As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.展开更多
Carbon dioxide(CO_(2))is the predominant greenhouse gas in the Earth’s atmosphere and plays a crucial role in global warming.Given the inherent limitations of monoethanolamine absorbents in current commercial large-s...Carbon dioxide(CO_(2))is the predominant greenhouse gas in the Earth’s atmosphere and plays a crucial role in global warming.Given the inherent limitations of monoethanolamine absorbents in current commercial large-scale CO_(2)capture applications,amino acid ionic liquids(AAILs)have garnered extensive interest in this field due to their adjustable structure,low volatility,high thermal stability,and significant absorption capacity.However,the number of comprehensive reviews recently published on the CO_(2)absorption by AAILs remains limited.In addition,researchers have differing opinions on the AAILs/CO_(2)reaction mechanisms.Therefore,this review provides a thorough overview of the reaction mechanisms and structure-activity relationships associated with AAILs for CO_(2)capture.Moreover,it outlines the research advancements in pure AAILs and their mixtures,including aqueous AAILs and AAIL-organic solvent mixtures.The effects of varying ionic structures and additives on the absorption properties of AAILs are examined in detail.In conclusion,although AAILs exhibit high CO_(2)absorption loading and possess numerous appealing characteristics,further research is essential to comprehensively evaluate their viability for large-scale CO_(2)capture from flue gas.展开更多
Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle a...Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle and the high oxide dissolution capacity of molten salts,CaO is herein introduced into the affordable molten NaCl-CaCl_(2)-FeO salt to generate CO_(3)^(2-)through an efficient capture of CO_(2).The subsequent coelectrolysis of FeO and CO_(3)^(2-)successfully produces cathodic Fe-encapsulated carbon nanotubes(Fe@CNT)with enhanced energy efficiency(current efficiency of 83.1%for CO_(2)reduction and energy consumption of 22.49 kWh kg^(1)for Fe@CNT generation).The in-situ capture of CO_(2)by O^(2)generated from the electro-deoxidation of FeO bridges the electrolysis of CO_(2)and FeO,rendering the enhanced current efficiency of the co-electrolysis and template-free generation of Fe@CNT.When evaluated as functional materials for electromagnetic wave absorption,the Fe@CNT integrates dielectric loss of CNT and electromagnetic loss from Fe.The Fe well-defined in CNT induces the synergistic loss and further improves the impedance matching,resulting in excellent electromagnetic wave absorption performance.The coelectrolysis establishes a promising strategy for converting CO_(2)into highly functional materials directly from CO_(2)-containing flue gas from steel industrial without dust removal.展开更多
The correlation between hydrogen absorption capacity(HAC)and the micro structure of Sm_(26.2)Co_(bal)Fe_(x)Cu_(4.0)Zr_(2.3)(x=23 wt%,25 wt%,27 wt%,30 wt%)ingots and cast strips was systematically investigated.As the t...The correlation between hydrogen absorption capacity(HAC)and the micro structure of Sm_(26.2)Co_(bal)Fe_(x)Cu_(4.0)Zr_(2.3)(x=23 wt%,25 wt%,27 wt%,30 wt%)ingots and cast strips was systematically investigated.As the temperature rises from 373 to 423 K,the activation time,hydrogen absorption time and HAC of the Sm_(26.2)Co_(bal)Fe_(23)Cu_(4.0)Zr_(2.3)ingot decrease by 14.4%,14.1%,and 19.3%,respectively.Dispersed 1:5phase provides more channels for hydrogen diffusion,which is the main reason that HAC increases with the x increasing.The HAC of the same compound strips increases as the particles size of the pre-crushed decreases.However,no further embrittlement behavior appears in pre-crushed strips,which reaches an equal HAC as ingots.Micro-computerized tomography reveals that ingots contain small spherical-like holes and large flake micro-cracks,whereas strips mainly contain elliptical pores.The effects of grain size and inner defects size on structure stability were invested by Abaqus.Simulation results reveal that the superior embrittlement behavior of the ingots is predominantly influenced by the presence of large flake-like micro-cracks.展开更多
基金The National Natural Science Foundation of China(No.51276038)
文摘A comprehensive computational fluid dynamics（CFD） model is developed based on the gas-liquid two-phase hydrodynamics,gas-liquid mass-transfer theory and chemical reaction kinetics,and the ammonia-based CO2 absorption in a spray column is numerically studied.The Euler-Lagrange model is applied to describe the behavior of gas-liquid twophase flowand heat transfer.The dual-film theory and related correlations are adopted to model the gas-liquid mass transfer and chemical absorption process.The volatilization model of multi-component droplet is utilized to account for ammonia slippage.The effect of operation parameters on CO2 removal efficiency is numerically studied.The results showa good agreement with the previous experimental data,proving the validity of the proposed model.The profile studies of gasphase velocity and CO2 concentration suggest that the flowfield has a significant impact on the CO2 concentration field.Also,the local CO2 absorption rate is influenced by both local turbulence and the local liquid-gas ratio.Furthermore,the velocity field of gas phase is optimized by the method of adjusting the orifice plate,and the results showthat the CO2 removal efficiency is improved by approximately 4%.
基金Supported by Hebei Provincial Natural Science Foundation for Distinguished Young Scholars of China(Grant No.B2015208067)Training Program for Talent Engineering of Hebei Province(Grant No.A2017002022)Key Program of Hebei Provincial Natural Science Foundation(Grant No.B2018208154)
文摘Phase change solvents are attractive energy-efficient absorbents for carbon dioxide(CO_2) capture due to CO_2-rich phase formation. Potassium prolinate + water + ethanol(ProK/W/Eth) solution has shown good capture characteristics as a promising one in our previous work. In this work, absorption rate of CO_2, solubility of N2 O,and heat of absorption for ProK/W/Eth solution were investigated using a stirred cell reactor and a CPA201 reaction calorimeter and these results were also compared with the aqueous ProK and 30 mass% MEA solutions.Using ethanol as a solvent can substantially increase the CO_2 physical solubility and the absorption rate of CO_2 in ProK/W/Eth solutions is far higher than that in aqueous 30 mass% MEA solutions especially at a low CO_2 loading range. Solid precipitation, obtained from the liquid-to-solid phase change absorption, was analyzed by13 C NMR and DSC-TGA. The enthalpy change for ProK/W/Eth solutions at various CO_2 loading was also discussed.
基金financially supported by the Brain Korea 21 Project in 2012the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.2006CCD11P011A -21-3-010)
文摘Aqueous 1,8-diamino-p-menthane （KIER-C3） and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol （AMP） solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine （MEA） and ammonia （NH3）, respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation： k2,AMP/C3 = 7.702×106 exp （-2248.03/T）. A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.
基金financially supported by National Natural Science Foundation of China(Grant Nos.12141203,52202083,W2421013)the Natural Science Foundation Project of Shaanxi Province(Grant No.2024JC-YBMS-450)+1 种基金the Sichuan Science and Technology Program(Grant No.2024YFHZ0265)the Open Project of High-end Equipment Advanced Materials and Manufacturing Technology Laboratory(Grant No.2023KFKT0005)。
文摘Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures were prepared through digital light processing(DLP)3D printing,polymer-derived ceramics(PDCs),chemical vapor infiltration(CVI),and oxidation technologies.The incorporation of the CVISiC phase effectively increases the dissipation capability,while the synergistic interaction between the gyroid structure and SiO_(2)phase significantly improves impedance matching performance.The SiOC/SiC/SiO_(2)composite achieved a minimum reflection loss(RL min)of-62.2 d B at 4.3 mm,and the effective absorption bandwidth(EAB)covered the X-band,with a thickness range of 4.1 mm-4.65 mm.The CST simulation results explain the broadband and low-frequency absorption characteristics,with an EAB of 8.4 GHz(9.6-18 GHz)and an RL min of-21.5 dB at 5 GHz.The excellent EM wave attenuation performance is associated primarily with polarization loss,conduction loss,the gyroid structure's enhancement of multiple reflections and scattering of EM waves,and the resonance effect between the structural units.The SiOC/SiC/SiO_(2)composite also demonstrated strong mechanical properties,with a maximum compressive failure strength of 31.6 MPa in the height direction.This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties.
基金supported by Korea Ministry of Environment (MOE) as "Human Resource Development Project for Waste to Energy"
文摘The carbon dioxide （CO2） removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine （MEA） ＋ 2-amino-2-methyl-l-propanol （AMP） solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA ＋ AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA ＋ 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA （0.41 mol CO2/mol amine）. Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.
文摘Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L^(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L^(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.
基金supported by the National Key R&D Program of China(Nos.2016YFD0700101 and 2016YFC0303902)the National Natural Science Foundation of China(Nos.61775079,61627823 and 61307124)+3 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2017A020216011)the Science and Technology Development Program of Jilin Province,China(No.20140307014SF)the Industrial Innovation Program of Jilin Province,China(No.2017C027)Changchun Municipal Science and Technology Bureau,China(No.14KG022)
文摘A dual-gas sensor system is developed for CO and CO_2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing(TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode(without rotation) and dynamic mode(with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million(ppm) in volume and 2.6 ppm for CO and CO_2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO_2, respectively. The reported sensor has potential applications in various fields requiring CO and CO_2 detection such as in the coal mine.
文摘Carbon dioxide （CO2） removal is an essential step in natural gas （NG） processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study alms to investigate the removal of CO2 at high concentration level from the mixture of CO2-NG gas stream at elevated pressure via absorption process. This is to explore the possibility of exploring high CO2 content natural gas reserves by treatment at offshore platform. A mixed amine solvent, Stonvent-II, was used for the absorption of approximately 75 vol% CO2 in CO2-NG stream at a pressure of 10 barg. The initial solvent temperature was varied in order to study the impact of initial temperature on the absorption performance. Preliminary study at temperatures of 35 ℃ and 45 ℃ indicates that Stonvent-II was able to perform almost 100% removal of CO2 under both conditions. However, the CO2 absorption effect took place faster when the initial liquid temperature was lower. This is because when the initial liquid temperature is high, the temperature increase in the packing bed caused by the reaction heat is high which impacts the efficiency of absorption negatively.
基金supported by the Special Fund for Major State Basic Research Projects of China(2010CB732206)
文摘The paper presents an energy performance assessment of CO2 removal for crude synthetic natural gas （SNG） upgrade by Selexol absorption process. A simplified process simulation of the Selexol process concerning power requirement and separation performance was developed. The assessment indicates that less pressure difference between crude SNG and absorption pressure favors the energy performance of CO2 removal process. When both crude SNG and absorption pressures are 20 bar, CO2 removal process has the best energy performance. The optimal specific power consumption of the CO2 removal process is 566 kJ/kgCO2. The sensitivity analysis shows that the CO2 removal efficiency would significantly influence the total power consumption of the removal process, as well as higher heating value （HHV） and CO2 content in SNG. However, the specific power consumption excluding crude SNG and SNG compressions changes little with the variance of CO2 removal efficiency. If by-product CO2 is compressed for CO2 capture, the process would turn into a CO2-sink for the atmosphere. Correspondingly, an increase of 281 kJ/kgCO2 in specific power consumption is required for compressing the separated CO2.
基金supported by the Sinopec Ningbo Engineering Co., Ltd.(No.l4850000-14-ZC0609-0003, H8XY-0032)
文摘At present monoethanolamine(MEA) remains as the standard industrial solvent for CO_2 capture processes. But due to the degradation and high energy consumption problems of MEA, new efficient solvents should be found. In the present work, the absorption and regeneration performance of a hybrid solvent MEA-methanol was studied and compared to the aqueous solutions of monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA) in a bubbling reactor. Also the performance of MEA-methanol solutions(including the absorption performance, regeneration performance,cyclic absorption performance, density and viscosity) was studied with different MEA concentrations. A pilot-plant CO_2 capture test bed was used to study the potential of MEA-methanol to replace aqueous MEA in industrial use. The results showed that the initial absorption rate of MEA-methanol solvent is the fastest compared with other solvents. The 30% MEA-methanol had a faster mass transfer coefficient, a higher CO_2 absorption efficiency and a lower regeneration energy consumption than aqueous MEA. And through the study of the reaction heat of CO_2 into MEA-methanol and aqueous MEA,it can be concluded that the desorption heat of rich MEA-methanol is only about 30% of rich aqueous MEA solvent in the regeneration process which showed that 30% MEA-methanol solvent is a promising candidate for CO_2 capture.
基金support from the National Key Research and Development Program of China(No.2021YFB3701503)the Key Research and Development Program of Ningbo,China(No.2023Z107)+1 种基金the Jiangsu Key R&D program,China(No.BE2019072)the special project of Gansu regional science and technology cooperation,China(No.20JR10 QA579).
文摘Exploring high-efficiency and broadband microwave absorption(MA)materials with corrosion resistance and low cost is ur-gently needed for wide practical applications.Herein,the natural porous attapulgite(ATP)nanorods embedded with TiO_(2)and polyaniline(PANI)nanoparticles are synthesized via heterogeneous precipitation and in-situ polymerization.The obtained PANI-TiO_(2)-ATP one-di-mensional(1D)nanostructures can intertwine into three-dimensional(3D)conductive network,which favors energy dissipation.The min-imum reflection loss(RL_(min))of the PANI-TiO_(2)-ATP coating(20wt%)reaches-49.36 dB at 9.53 GHz,and the effective absorption band-width(EAB)can reach 6.53 GHz with a thickness of 2.1 mm.The excellent MA properties are attributed to interfacial polarization,mul-tiple loss mechanisms,and good impedance matching induced by the synergistic effect of PANI-TiO_(2)nanoparticle shells and ATP nanor-ods.In addition,salt spray and Tafel polarization curve tests reveal that the PANI-TiO_(2)-ATP coating shows outstanding corrosion resist-ance performance.This study provides a low-cost and high-efficiency strategy for constructing 1D nanonetwork composites for MA and corrosion resistance applications using natural porous ATP nanorods as carriers.
基金supported by the PhD Start-up Fund of the Science and Technology Department of Liaoning Province(No.2022-BS-306)the General Cultivation Scientific Research Project of Bohai University(No.0522xn058)the PhD Research Startup Foundation of Bohai University(No.0521bs021).
文摘The preparation of electromagnetic(EM)wave absorption materials provided with the characteristics of thin matching thickness,broad bandwidth,and mighty absorption intensity is an efficient solution to current EM pollution.Herein,Graphene nanosheets(GN)were firstly fabricated via a facile high-energy ball milling method,subsequently high-purity 1T-MoS_(2) petals were uniformly anchored on the surface of GN to prepare 1T-MoS_(2)@GN nanocomposites.Plentiful multiple reflection and scattering of EM waves in a distinctive multidimensional structure formed by GN and 1T-MoS_(2),copious polarization loss consisting of interfacial polarization loss and dipolar polarization loss severally derived from multitudinous heterointerfaces and profuse electric dipoles in 1T-MoS_(2)@GN,and mighty conduction loss originated from plentiful induced current in 1T-MoS_(2)@GN generated via the migration of massive electrons,all of which endowed 1T-MoS_(2)@GN nanocomposites with exceptional EM wave absorption performances.The minimum reflection loss(RLmin)of 1T-MoS_(2)@GN reached–50.14 dB at a thickness of only 2.10 mm,and the effective absorption bandwidth(EAB)was up to 6.72 GHz at an ultra-thin matching thickness of 1.84 mm.Moreover,the radar scattering cross section(RCS)reduction value of 36.18 dB m2 at 0°could be achieved as well,which ulteriorly validated the tremendous potential of 1T-MoS_(2)@GN nanocomposites in practical applications.
基金financially supported by the Key Project of Natural Science Research in Colleges and Universities of Anhui Province,China(No.2022AH050816)the Open Research Grant of Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining(Nos.EC2023013 and EC2022018)+1 种基金the National Natural Science Foundation of China(No.52200139)the Introduction of Talent in Anhui University of Science and Technology,China(Nos.2021yjrc18 and 2023yjrc79)。
文摘Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_(4)/residual carbon from coal gasification fine slag(CFO/RC)composites were created using a novel hydrothermal method.Various mechanisms for microwave absorption,including conductive loss,natural resonance,interfacial dipole polarization,and magnetic flux loss,are involved in these composites.Consequently,compared with pure residual carbon materials,this composite offers superior capabilities in microwave absorption.At 7.76GHz,the CFO/RC-2 composite achieves an impressive minimum reflection loss(RL_(min))of-43.99 dB with a thickness of 2.44 mm.Moreover,CFO/RC-3 demonstrates an effective absorption bandwidth(EAB)of up to 4.16 GHz,accompanied by a thickness of 1.18mm.This study revealed the remarkable capability of the composite to diminish electromagnetic waves,providing a new generation method for microwave absorbing materials of superior quality.
基金supported by the National Key R&D Program of China(Nos.2023YFF0718303 and 2022YFB3504804)the National Natural Science Foundation of China(Nos.51871219,52031014 and 52401255)the Science and Technology Project of Shenyang City(No.22-101-0-27).
文摘The single-layer Ti_(3)C_(2)T_(x)/MXene has become a special electromagnetic wave absorber near the terahertz band because of its abundant surface groups and excellent conductivity.However,the macro-preparation of single-layer Ti_(3)C_(2)T_(x)/MXene shows significantly difficult to influence its application.The two-dimensional Ti_(3)C_(2)T_(x)is easily prepared to have high production,but its weak absorption ability due to high surface conductivity also restricts its application.To realize the strong electromagnetic wave absorption of two-dimensional Ti_(3)C_(2)T_(x)/MXene,a new strategy with magnetic FeNi nanoparticles decorating Ti_(3)C_(2)T_(x)/MXene composites(FeNi-Ti_(3)C_(2)T_(x))were proposed and the effective electromagnetic wave absorption features covering 170-220 GHz that means the absorption band width reach 50 GHz.With an absorber composite film thickness being only 0.6 mm,the absorptivity of the composite is enhanced with the increase of decorating FeNi nanoparticles and promote up to 75%when the FeNi nanoparticles loading content reaches 30 wt%.The improvement of absorption is attributed to the introduction of soft magnetic FeNi to adjust the high surface conductivity of MXene and improve the electromagnetic balance of the absorber.
基金supported by the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.
基金support from the National Key Research and Development Program of China(No.2021YFB3701503)the Key Research and Development Program of Ningbo,China(No.2023Z107).
文摘As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.
基金supported by the Natural Science Foundation of Shanghai(Grant No.24ZR1426200)the support from the Key Program of the National Natural Science Foundation of China(Grant No.52236004)。
文摘Carbon dioxide(CO_(2))is the predominant greenhouse gas in the Earth’s atmosphere and plays a crucial role in global warming.Given the inherent limitations of monoethanolamine absorbents in current commercial large-scale CO_(2)capture applications,amino acid ionic liquids(AAILs)have garnered extensive interest in this field due to their adjustable structure,low volatility,high thermal stability,and significant absorption capacity.However,the number of comprehensive reviews recently published on the CO_(2)absorption by AAILs remains limited.In addition,researchers have differing opinions on the AAILs/CO_(2)reaction mechanisms.Therefore,this review provides a thorough overview of the reaction mechanisms and structure-activity relationships associated with AAILs for CO_(2)capture.Moreover,it outlines the research advancements in pure AAILs and their mixtures,including aqueous AAILs and AAIL-organic solvent mixtures.The effects of varying ionic structures and additives on the absorption properties of AAILs are examined in detail.In conclusion,although AAILs exhibit high CO_(2)absorption loading and possess numerous appealing characteristics,further research is essential to comprehensively evaluate their viability for large-scale CO_(2)capture from flue gas.
基金supported by the National Key R&D Program of China(2023YFA1508001)the National Natural Science Foundation of China(22272120 and U2202251)+2 种基金the Fundamental Research Funds for the Central Universities(2042022kf1174)the Hainan Province Science and Technology Special Fund(ZDYF2023SHFZ120 and ZDYF2021SHFZ058)the Research Foundation of Marine Science and Technology Collaborative Innovation Center of Hainan University(XTCX2022HYB01)。
文摘Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle and the high oxide dissolution capacity of molten salts,CaO is herein introduced into the affordable molten NaCl-CaCl_(2)-FeO salt to generate CO_(3)^(2-)through an efficient capture of CO_(2).The subsequent coelectrolysis of FeO and CO_(3)^(2-)successfully produces cathodic Fe-encapsulated carbon nanotubes(Fe@CNT)with enhanced energy efficiency(current efficiency of 83.1%for CO_(2)reduction and energy consumption of 22.49 kWh kg^(1)for Fe@CNT generation).The in-situ capture of CO_(2)by O^(2)generated from the electro-deoxidation of FeO bridges the electrolysis of CO_(2)and FeO,rendering the enhanced current efficiency of the co-electrolysis and template-free generation of Fe@CNT.When evaluated as functional materials for electromagnetic wave absorption,the Fe@CNT integrates dielectric loss of CNT and electromagnetic loss from Fe.The Fe well-defined in CNT induces the synergistic loss and further improves the impedance matching,resulting in excellent electromagnetic wave absorption performance.The coelectrolysis establishes a promising strategy for converting CO_(2)into highly functional materials directly from CO_(2)-containing flue gas from steel industrial without dust removal.
基金Project supported by the National Key Research and Development Program of China(2022YFB3505303,2021YFB3503100,2021YFB3501500)the Major Projects in Inner Mongolia Autonomous Region of China(2021ZD0035)。
文摘The correlation between hydrogen absorption capacity(HAC)and the micro structure of Sm_(26.2)Co_(bal)Fe_(x)Cu_(4.0)Zr_(2.3)(x=23 wt%,25 wt%,27 wt%,30 wt%)ingots and cast strips was systematically investigated.As the temperature rises from 373 to 423 K,the activation time,hydrogen absorption time and HAC of the Sm_(26.2)Co_(bal)Fe_(23)Cu_(4.0)Zr_(2.3)ingot decrease by 14.4%,14.1%,and 19.3%,respectively.Dispersed 1:5phase provides more channels for hydrogen diffusion,which is the main reason that HAC increases with the x increasing.The HAC of the same compound strips increases as the particles size of the pre-crushed decreases.However,no further embrittlement behavior appears in pre-crushed strips,which reaches an equal HAC as ingots.Micro-computerized tomography reveals that ingots contain small spherical-like holes and large flake micro-cracks,whereas strips mainly contain elliptical pores.The effects of grain size and inner defects size on structure stability were invested by Abaqus.Simulation results reveal that the superior embrittlement behavior of the ingots is predominantly influenced by the presence of large flake-like micro-cracks.
