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High-efficiency CO sequestration through direct aqueous carbonation of carbide slag: determination ofcarbonation reaction and optimization of operation parameters

《环境科学与工程前沿(英文)》 2024年 第18卷 第1期 doi: 10.1007/s11783-024-1772-y

摘要:

● The sequestration capacity of 610.8 g CO2/kg was achieved for carbide slag.

关键词: Industrial by-products     Direct aqueous carbonation     CO2 sequestration     Mass transfer    

A stepwise process for carbon dioxide sequestration using magnesium silicates

Johan FAGERLUND, Experience NDUAGU, Ron ZEVENHOVEN, Inês ROMÃO,

《化学科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 133-141 doi: 10.1007/s11705-009-0259-5

摘要: This work involves the production of magnesium in the form of Mg(OH) from serpentinite rock (nickel mine tailing) material followed by conversion into MgCO using a pressurised fluidised bed (PFB) reactor operating at 400°C–600°C and pressures up to 2.85MPa. Our approach is rooted in the thermodynamic fact that the reaction between Mg(OH) and gaseous CO forming MgCO and water releases significant amounts of heat. The main problem is, however, the chemical kinetics; the reaction is slow and has to be accelerated in order to be used in an economically viable process for large-scale (~1Mt/a) CO sequestration. We have constructed a lab-scale PFB reactor test-setup for optimising the carbonation reaction. At high enough temperatures and conversion levels the reaction should provide the heat for the proceeding Mg(OH) production step, making the overall process energy neutral. So far we have been able to achieve a conversion degree of 26% at 500°C and 2.85MPa after 30min (particle size 125–212μm). In this paper the test facility and our latest results and progress on CO mineral carbonation are summarised. Also, the possible integration of the iron as a feedstock for iron and steel production will be briefly addressed. An interesting side-effect of this carbon dioxide capture and storage (CCS) route is that significant amounts of iron are obtained from the serpentinite rock material. This is released during the Mg(OH) production and can be of great interest to the iron- and steel producing sector, which at the same time is Finland’s largest CO producer.

关键词: carbonation reaction     reactor     producer     large-scale     process    

Operando modeling and measurements: Powerful tools for revealing the mechanism of alkali carbonate-based sorbents for CO capture in real conditions

《能源前沿(英文)》 2023年 第17卷 第3期   页码 380-389 doi: 10.1007/s11708-023-0872-x

摘要: Alkali carbonate-based sorbents (ACSs), including Na2CO3- and K2CO3-based sorbents, are promising for CO2 capture. However, the complex sorbent components and operation conditions lead to the versatile kinetics of CO2 sorption on these sorbents. This paper proposed that operando modeling and measurements are powerful tools to understand the mechanism of sorbents in real operating conditions, facilitating the sorbent development, reactor design, and operation parameter optimization. It reviewed the theoretical simulation achievements during the development of ACSs. It elucidated the findings obtained by utilizing density functional theory (DFT) calculations, ab initio molecular dynamics (AIMD) simulations, and classical molecular dynamics (CMD) simulations as well. The hygroscopicity of sorbent and the humidity of gas flow are crucial to shifting the carbonation reaction from the gas−solid mode to the gas−liquid mode, boosting the kinetics. Moreover, it briefly introduced a machine learning (ML) approach as a promising method to aid sorbent design. Furthermore, it demonstrated a conceptual compact operando measurement system in order to understand the behavior of ACSs in the real operation process. The proposed measurement system includes a micro fluidized-bed (MFB) reactor for kinetic analysis, a multi-camera sub-system for 3D particle movement tracking, and a combined Raman and IR sub-system for solid/gas components and temperature monitoring. It is believed that this system is useful to evaluate the real-time sorbent performance, validating the theoretical prediction and promoting the industrial scale-up of ACSs for CO2 capture.

关键词: CO2 capture     carbonation     theoretical modeling     operando techniques     reaction visualization    

A combination process of mineral carbonation with SO2 disposal for simulated flue gas by magnesia-added

Yingying Zhao, Mengfan Wu, Zhiyong Ji, Yuanyuan Wang, Jiale Li, Jianlu Liu, Junsheng Yuan

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 832-844 doi: 10.1007/s11705-019-1871-7

摘要: The desulfurization by seawater and mineral carbonation have been paid more and more attention. In this study, the feasibility of magnesia and seawater for the integrated disposal of SO and CO in the simulated flue gas was investigated. The process was conducted by adding MgO in seawater to reinforce the absorption of SO and facilitate the mineralization of CO by calcium ions. The influences of various factors, including digestion time of magnesia, reaction temperature, and salinity were also investigated. The results show that the reaction temperature can effectively improve the carbonation reaction. After combing SO removal process with mineral carbonation, Ca removal rate has a certain degree of decrease. The best carbonation condition is to use 1.5 times artificial seawater (the concentrations of reagents are 1.5 times of seawater) at 80°C and without digestion of magnesia. The desulfurization rate is close to 100% under any condition investigated, indicating that the seawater has a sufficient desulfurization capacity with adding magnesia. This work has demonstrated that a combination of the absorption of SO with the absorption and mineralization of CO is feasible.

关键词: mineral carbonation     wet SO2 disposal     seawater     desulfurization    

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 150-161 doi: 10.1007/s11709-016-0341-2

摘要: Enhancing service life of reinforced concrete (RC) structures located in marine environments is an issue of great interest for design engineers. The present research addresses the effect of surface coatings on service life of onshore RC structures. Long-term performance of concrete samples up to 88 months of exposure at natural marine environment was investigated. Two onshore exposure conditions, including soil and atmosphere and different types of concrete coatings were studied. Carbonation rates of up to 0.5 and 1.5 mm/year were observed at the first 88 months of exposure for soil and atmospheric samples, respectively. Surface chloride ion build-up and variation in chloride ion diffusion were monitored with respect to time, and service life was estimated. Based on the obtained results it is proposed to use the aliphatic acrylic and polyurethane coatings for enhancing the service life of concrete structures in the investigated exposure conditions.

关键词: carbonation     chloride ion     corrosion     service life     surface coating    

comparison of different regression techniques and nature-inspired optimization algorithms to predict carbonation

《结构与土木工程前沿(英文)》 2023年 第18卷 第1期   页码 30-50 doi: 10.1007/s11709-024-1041-y

摘要: The utilization of recycled aggregates (RA) for concrete production has the potential to offer substantial environmental and economic advantages. However, RA concrete is plagued with considerable durability concerns, particularly carbonation. To advance the application of RA concrete, the establishment of a reliable model for predicting the carbonation is needed. On the one hand, concrete carbonation is a long and slow process and thus consumes a lot of time and energy to monitor. On the other hand, carbonation is influenced by many factors and is hard to predict. Regarding this, this paper proposes the use of machine learning techniques to establish accurate prediction models for the carbonation depth (CD) of RA concrete. Three types of regression techniques and meta-heuristic algorithms were employed to provide more alternative predictive tools. It was found that the best prediction performance was obtained from extreme gradient boosting-multi-universe optimizer (XGB-MVO) with R2 value of 0.9949 and 0.9398 for training and testing sets, respectively. XGB-MVO was used for evaluating physical laws of carbonation and it was found that the developed XGB-MVO model could provide reasonable predictions when new data were investigated. It also showed better generalization capabilities when compared with different models in the literature. Overall, this paper emphasizes the need for sustainable solutions in the construction industry to reduce its environmental impact and contribute to sustainable and low-carbon economies.

关键词: recycled aggregate concrete     carbonation depth     nature-inspired optimization algorithms     extreme gradient boosting technique     parametric analysis    

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 473-486 doi: 10.1007/s11709-020-0608-5

摘要: Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted. However, these previous studies did not consider the effects of climate change, such as acceleration in the deterioration of durability, on mixture design. This study presents a procedure for the optimal mixture design of ternary blended concrete considering climate change and durability. First, the costs of CO emissions and material are calculated based on the concrete mixture and unit prices. Total cost is equal to the sum of material cost and CO emissions cost, and is set as the objective function of the optimization. Second, strength, slump, carbonation, and chloride ingress models are used to evaluate concrete properties. The effect of different climate change scenarios on carbonation and chloride ingress is considered. A genetic algorithm is used to find the optimal mixture considering various constraints. Third, illustrative examples are shown for mixture design of ternary blended concrete. The analysis results show that for ternary blended concrete exposed to an atmospheric environment, a rich mix is necessary to meet the challenge of climate change, and for ternary blended concrete exposed to a marine environment, the impact of climate change on mixture design is marginal.

关键词: ternary blended concrete     climate change     optimal mixture design     carbonation     chloride ingress    

A novel sequence batch membrane carbonation photobioreactor developed for microalgae cultivation

Caiyun Hou, Sen Qiao, Yue Yang, Jiti Zhou

《环境科学与工程前沿(英文)》 2019年 第13卷 第6期 doi: 10.1007/s11783-019-1176-6

摘要: • A novel SBM-C-PBR was constructed for microalgae cultivation. • Membrane fouling was greatly mitigated by membrane carbonation. • NH4+ and P removal rates were around 80% in SBM-C-PBR. • Biomass was completely retained by membrane. In this study, a novel sequence batch membrane carbonation photobioreactor was developed for microalgae cultivation. Herein, membrane module was endowed functions as microalgae retention and CO2 carbonation. The results in the batch experiments expressed that the relatively optimal pore size of membranes was 30 nm, photosynthetically active radiation was 36 W/m2 and the CO2 concentration was 10% (v/v). In long-term cultivation, the microalgal concentration separately accumulated up to 1179.0 mg/L and 1296.4 mg/L in two periods. The concentrations of chlorophyll a, chlorophyll b and carotenoids were increased about 23.2, 14.9 and 6.3 mg/L respectively in period I; meanwhile, the accumulation was about 25.0, 14.5, 6.6 mg/L respectively in the period II. Furthermore, the pH was kept about 5.5–7.5 due to intermittent carbonation mode, which was suitable for the growth of microalgae. Transmembrane pressure (TMP) was only increased by 0.19 and 0.16 bar in the end of periods I and II, respectively. The pure flux recovered to 75%–80% of the original value by only hydraulic cleaning. Scanning electron microscope images also illustrated that carbonation through membrane module could mitigate fouling levels greatly.

关键词: Membrane carbonation     SBM-C-PBR     Cultivate microalgae     Membrane fouling    

Simulation on thermodynamic state of ammonia carbonation at low temperature and low pressure

Jingcai ZHAO, Xingfu SONG, Ze SUN, Jianguo YU

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 447-455 doi: 10.1007/s11705-013-1370-1

摘要: This study on thermodynamic property of NH -CO -H O system provided the basic data for ammonia carbonation. Simulations on vapor-liquid equilibrium (VLE) of ammonia carbonation with different physical properties were discussed in NH -H O and NH -CO -H O systems, respectively. The results indicated that at low temperature (303.15 K–363.15 K) and pressure (0.1–0.4 MPa), the PR (Peng-Robinson) equation was suitable for the description of the thermodynamic state in NH -H O system. NRTL (Non-Random-Two-Liquid) series models were selected for NH -CO -H O mixed electrolyte solution system. VLE data regression results showed that NRTL series models were suitable for describing thermodynamic properties of NH -CO -H O system, because average relative error fitting with each model was about 1%. As an asymmetric electrolytes model in NRTL model, E–NRTLRK (Electrolyte NRTL Redlich Kwong) could most accurately fit VLE data of NH -CO -H O system, with fitting error less than 1%. In the extent temperature range of 273.15 K–363.15 K, the prediction of product component using E-NRTLRK model for ammonia carbonation agreed well with the data reported in literature.

关键词: vapor-liquid equilibrium     activity coefficient     carbon dioxide     ammonia     NRTL    

Prediction on CO

Kaiwen HUANG, Ao LI, Bing XIA, Tao DING

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 746-759 doi: 10.1007/s11709-020-0635-2

摘要: Carbonation of concrete is a process which absorbs carbon dioxide (CO ). Recycled aggregate concrete (RAC) may own greater potential in CO uptake due to the faster carbonation rate than natural aggregate concrete (NAC). A quantitative model was employed to predict the CO uptake of RAC in this study. The carbonation of RAC and the specific surface area of recycled coarse aggregates (RCAs) were tested to verify accuracy of the quantitative model. Based on the verified model, results show that the CO uptake capacity increases with the increase of RCA replacement percentage. The CO uptake amount of 1 m C30 RAC within 50 years is 10.6, 13.8, 17.2, and 22.4 kg when the RCA replacement percentage is 30%, 50%, 70%, and 100%, respectively. The CO uptake by RCAs is remarkable and reaches 35.8%–64.3% of the total CO uptake by RAC when the RCA storage time being 30 days. Considering the fact that the amount of old hardened cement paste in RCAs is limited, there is an upper limit for the CO uptake of RCAs.

关键词: RAC     CO2 uptake     carbonation     specific surface area     RCA    

Service life prediction of fly ash concrete using an artificial neural network

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 793-805 doi: 10.1007/s11709-021-0717-9

摘要: Carbonation is one of the most aggressive phenomena affecting reinforced concrete structures and causing their degradation over time. Once reinforcement is altered by carbonation, the structure will no longer fulfill service requirements. For this purpose, the present work estimates the lifetime of fly ash concrete by developing a carbonation depth prediction model that uses an artificial neural network technique. A collection of 300 data points was made from experimental results available in the published literature. Backpropagation training of a three-layer perceptron was selected for the calculation of weights and biases of the network to reach the desired performance. Six parameters affecting carbonation were used as input neurons: binder content, fly ash substitution rate, water/binder ratio, CO2 concentration, relative humidity, and concrete age. Moreover, experimental validation carried out for the developed model shows that the artificial neural network has strong potential as a feasible tool to accurately predict the carbonation depth of fly ash concrete. Finally, a mathematical formula is proposed that can be used to successfully estimate the service life of fly ash concrete.

关键词: concrete     fly ash     carbonation     neural networks     experimental validation     service life    

In-situ condition monitoring of reinforced concrete structures

Sanjeev Kumar VERMA,Sudhir Singh BHADAURIA,Saleem AKHTAR

《结构与土木工程前沿(英文)》 2016年 第10卷 第4期   页码 420-437 doi: 10.1007/s11709-016-0336-z

摘要: Performance of concrete structures is significantly influenced and governed by its durability and resistance to environmental or exposure conditions, apart from its physical strength. It can be monitored, evaluated and predicted through modeling of physical deterioration mechanisms, performance characteristics and parameters and condition monitoring of in situ concrete structures. One such study has been conducted using Non-destructive testing equipment in the city of Bhopal and around located in India. Some selected parameters influencing durability of reinforced concrete (RC) structures such as concrete cover, carbonation depth, chloride concentration, half cell potential and compressive strength have been measured, for establishing correlation among various parameters and age of structures. Effects of concrete cover and compressive strength over the variation of chloride content with time are also investigated.

关键词: concrete     carbonation     chloride     corrosion     monitoring     models    

Advances in catalysts and reaction systems for electro/photocatalytic ammonia production

《化学科学与工程前沿(英文)》 doi: 10.1007/s11705-024-2463-8

摘要: Ammonia is a vital component in the fertilizer and chemical industries, as well as serving as a significant carrier of renewable hydrogen energy. Compared with the industry’s principal technique, the Haber-Bosch method, for ammonia synthesis, electro/photocatalytic ammonia synthesis is increasingly recognized as a viable and eco-friendly alternative. This method enables distributed small-scale deployment and can be powered by sustainable renewable energy sources. However, the efficiency of electro/photocatalytic nitrogen reduction reaction is hindered by the challenges in activating the N≡N bond and nitrogen’s low solubility, thereby limiting its large-scale industrial applications. In this review, recent advancements in electro/photocatalytic nitrogen reduction are summarized, encompassing the complex reaction mechanisms, as well as the effective strategies for developing electro/photocatalytic catalysts and advanced reaction systems. Furthermore, the energy efficiency and economic analysis of electro/photocatalytic nitrogen fixation are deeply discussed. Finally, some unsolved challenges and potential opportunities are discussed for the future development of electro/photocatalytic ammonia synthesis.

关键词: ammonia synthesis     electro/photocatalysis     nitrogen fixation     reaction system     economic and efficiency analysis    

Long-term effects of electrochemical realkalization on carbonated concrete

Peng ZHU, Ji ZHANG, Wenjun QU

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 127-137 doi: 10.1007/s11709-019-0583-x

摘要: The long-term effects of electrochemical realkalization on carbonated reinforced concrete with a / ratio of 0.65 were studied. Fourteen out of 16 carbonated specimens had been subjected to realkalization seven years ago, and the alkalinity of the concrete, the electrochemical characters (corrosion current density and potential) of the specimens and the corrosion conditions of the steel bars were examined. Results of different specimens and also at different time (4, 10, 13 months and 7 years after realkalization) were compared. According to the phenolphthalein and pH meter test, the alkalinity of the concrete had disappeared after seven years. Based on the potentiodynamic polarization test, various corrosion conditions had developed on the steel bars, which was verified by visual observation. All bars were in the depassivated state, and their corrosion current densities increased significantly after seven years. Cracks developed in some of the specimens, and the diverse compactness of concrete and excessive current of realkalization were considered to be possible causes. The effects of the realkalization treatment vanished after seven years.

关键词: realkalization     concrete     carbonation     polarization curve     corrosion    

Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1700-1712 doi: 10.1007/s11705-022-2207-6

摘要: The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins from a thermodynamic point of view.

关键词: naphtha     catalytic pyrolysis     reaction pathway     equilibrium yield    

标题 作者 时间 类型 操作

High-efficiency CO sequestration through direct aqueous carbonation of carbide slag: determination ofcarbonation reaction and optimization of operation parameters

期刊论文

A stepwise process for carbon dioxide sequestration using magnesium silicates

Johan FAGERLUND, Experience NDUAGU, Ron ZEVENHOVEN, Inês ROMÃO,

期刊论文

Operando modeling and measurements: Powerful tools for revealing the mechanism of alkali carbonate-based sorbents for CO capture in real conditions

期刊论文

A combination process of mineral carbonation with SO2 disposal for simulated flue gas by magnesia-added

Yingying Zhao, Mengfan Wu, Zhiyong Ji, Yuanyuan Wang, Jiale Li, Jianlu Liu, Junsheng Yuan

期刊论文

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

期刊论文

comparison of different regression techniques and nature-inspired optimization algorithms to predict carbonation

期刊论文

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

期刊论文

A novel sequence batch membrane carbonation photobioreactor developed for microalgae cultivation

Caiyun Hou, Sen Qiao, Yue Yang, Jiti Zhou

期刊论文

Simulation on thermodynamic state of ammonia carbonation at low temperature and low pressure

Jingcai ZHAO, Xingfu SONG, Ze SUN, Jianguo YU

期刊论文

Prediction on CO

Kaiwen HUANG, Ao LI, Bing XIA, Tao DING

期刊论文

Service life prediction of fly ash concrete using an artificial neural network

期刊论文

In-situ condition monitoring of reinforced concrete structures

Sanjeev Kumar VERMA,Sudhir Singh BHADAURIA,Saleem AKHTAR

期刊论文

Advances in catalysts and reaction systems for electro/photocatalytic ammonia production

期刊论文

Long-term effects of electrochemical realkalization on carbonated concrete

Peng ZHU, Ji ZHANG, Wenjun QU

期刊论文

Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

期刊论文