Pub Date : 2025-01-09DOI: 10.1016/j.joei.2025.101987
Nik Nor Aznizam Nik Norizam , Xin Yang , Nik Nor Azrizam Nik Norizam , Derek Ingham , Janos Szuhánszki , Lin Ma , Mohamed Pourkashanian
An improved predictive numerical index has been developed to predict the tendency of bed agglomeration in fluidized bed boilers. The index was developed based on the melt fraction resulting from the thermodynamic equilibrium model of fuel ash compositions together with SiO2 as the bed material at temperatures ranging from 700 to 900 °C. The partial least squares regression (PLSR) coupled with the cross-validation technique is utilized to establish the correlation for the bed agglomeration index, Ia. The improved index, Ia has been validated by experimental observations found in various literature sources. The results obtained using the improved index, Ia demonstrated a significantly higher success rate in predicting the bed agglomeration tendency of biomass fuel ash compared to the other four conventional bed agglomeration indices. In addition, K2O is the main element that accelerates the formation of bed agglomeration in the biomass firing while CaO was found to reduce the tendency of bed agglomeration in the fluidized bed combustion system.
{"title":"An improved numerical model for early detection of bed agglomeration in fluidized bed combustion","authors":"Nik Nor Aznizam Nik Norizam , Xin Yang , Nik Nor Azrizam Nik Norizam , Derek Ingham , Janos Szuhánszki , Lin Ma , Mohamed Pourkashanian","doi":"10.1016/j.joei.2025.101987","DOIUrl":"10.1016/j.joei.2025.101987","url":null,"abstract":"<div><div>An improved predictive numerical index has been developed to predict the tendency of bed agglomeration in fluidized bed boilers. The index was developed based on the melt fraction resulting from the thermodynamic equilibrium model of fuel ash compositions together with SiO<sub>2</sub> as the bed material at temperatures ranging from 700 to 900 °C. The partial least squares regression (PLSR) coupled with the cross-validation technique is utilized to establish the correlation for the bed agglomeration index, I<sub>a</sub>. The improved index, I<sub>a</sub> has been validated by experimental observations found in various literature sources. The results obtained using the improved index, I<sub>a</sub> demonstrated a significantly higher success rate in predicting the bed agglomeration tendency of biomass fuel ash compared to the other four conventional bed agglomeration indices. In addition, K<sub>2</sub>O is the main element that accelerates the formation of bed agglomeration in the biomass firing while CaO was found to reduce the tendency of bed agglomeration in the fluidized bed combustion system.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101987"},"PeriodicalIF":5.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spray flows are crucial in a variety of engineering applications across sectors such as energy and mobility, particularly in enhancing the performance of internal combustion engines, which are integral to the transition to net-zero emissions. However, accurately characterising these flows presents significant challenges due to the complex multiphysics and multiscale phenomena involved, especially when modelling reacting spray flows with turbulence-chemistry interactions. Machine learning (ML) algorithms present promising data-driven solutions that could enhance the accuracy and efficiency of computational fluid dydnamics (CFD) models, uncover underlying physical mechanisms, and optimise spray flow processes. This paper outlines the challenges and opportunities associated with integrating CFD and ML algorithms for spray flow modelling, with a particular focus on spray combustion to improve predictive capabilities. It provides a comprehensive review of existing literature on various CFD models and ML algorithms applied to key aspects of spray dynamics, such as atomisation, droplet transport, and combustion. Despite significant progress, ML applications in spray modelling continue to face challenges, primarily due to the complexity and variability of spray dynamics. These challenges include the need for high-quality, domain-specific data, which is often difficult and costly to obtain, as well as issues related to model generalisation. Furthermore, the wide range of scales inherent in spray flows along with the challenges in quantifying uncertainties present significant difficulties for ML models. The insights provided in this study can contribute to identifying research areas to improve the accuracy of spray modelling.
{"title":"Data-driven modelling of spray flows: Current status and future direction","authors":"Fatemeh Salehi , Amin Beheshti , Esmaeel Eftekharian , Longfei Chen , Yannis Hardalupas","doi":"10.1016/j.joei.2025.101991","DOIUrl":"10.1016/j.joei.2025.101991","url":null,"abstract":"<div><div>Spray flows are crucial in a variety of engineering applications across sectors such as energy and mobility, particularly in enhancing the performance of internal combustion engines, which are integral to the transition to net-zero emissions. However, accurately characterising these flows presents significant challenges due to the complex multiphysics and multiscale phenomena involved, especially when modelling reacting spray flows with turbulence-chemistry interactions. Machine learning (ML) algorithms present promising data-driven solutions that could enhance the accuracy and efficiency of computational fluid dydnamics (CFD) models, uncover underlying physical mechanisms, and optimise spray flow processes. This paper outlines the challenges and opportunities associated with integrating CFD and ML algorithms for spray flow modelling, with a particular focus on spray combustion to improve predictive capabilities. It provides a comprehensive review of existing literature on various CFD models and ML algorithms applied to key aspects of spray dynamics, such as atomisation, droplet transport, and combustion. Despite significant progress, ML applications in spray modelling continue to face challenges, primarily due to the complexity and variability of spray dynamics. These challenges include the need for high-quality, domain-specific data, which is often difficult and costly to obtain, as well as issues related to model generalisation. Furthermore, the wide range of scales inherent in spray flows along with the challenges in quantifying uncertainties present significant difficulties for ML models. The insights provided in this study can contribute to identifying research areas to improve the accuracy of spray modelling.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101991"},"PeriodicalIF":5.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.joei.2025.101993
Fatih Güleç , Jude A. Okolie
The kinetics of Chemical Looping Combustion (CLC) using Co3O4 as an oxygen carrier for low-volatile semi-anthracite coal were studied with the aim of integrating CO2 capture into the combustion process. The effectiveness of varying temperature regimes (800–950 °C) and oxygen carrier ratios (ϕ = 0.5–2.0) on the CLC process was evaluated. The findings indicate a distinct two-stage combustion sequence: initially, the combustion of volatiles with solid Co3O4 occurs between 460 and 650 °C, followed by the combustion of fixed carbon with gas-phase oxygen released from Co3O4 between 750 and 950 °C. Moreover, the activation energy for volatile combustion was found to be 82 kJ/mol, while for fixed carbon combustion during the non-isothermal stage, it ranged from 31 to 140 kJ/mol. During the isothermal stage, the activation energy for fixed carbon combustion was approximately 234 kJ/mol, with a reaction rate constant (k₀) of 3.7 × 108 s⁻1. The kinetics varied from diffusion-controlled reactions at lower temperatures to first-order or phase-boundary-controlled reactions, and then to Avrami-Erofeev modeled kinetics at higher temperatures, influenced by both temperature and oxygen carrier ratios. This pioneering study provides a comprehensive analysis of the multi-stage kinetics of solid fuel CLC, bridging gaps in current knowledge and laying the groundwork for improved design and efficiency of CLC systems for cleaner energy conversion.
{"title":"Chemical looping combustion of low-volatile semi-anthracite coal with Co-based metal oxide: Performances, kinetics, and mechanisms","authors":"Fatih Güleç , Jude A. Okolie","doi":"10.1016/j.joei.2025.101993","DOIUrl":"10.1016/j.joei.2025.101993","url":null,"abstract":"<div><div>The kinetics of Chemical Looping Combustion (CLC) using Co<sub>3</sub>O<sub>4</sub> as an oxygen carrier for low-volatile semi-anthracite coal were studied with the aim of integrating CO<sub>2</sub> capture into the combustion process. The effectiveness of varying temperature regimes (800–950 °C) and oxygen carrier ratios (ϕ = 0.5–2.0) on the CLC process was evaluated. The findings indicate a distinct two-stage combustion sequence: initially, the combustion of volatiles with solid Co<sub>3</sub>O<sub>4</sub> occurs between 460 and 650 °C, followed by the combustion of fixed carbon with gas-phase oxygen released from Co<sub>3</sub>O<sub>4</sub> between 750 and 950 °C. Moreover, the activation energy for volatile combustion was found to be 82 kJ/mol, while for fixed carbon combustion during the non-isothermal stage, it ranged from 31 to 140 kJ/mol. During the isothermal stage, the activation energy for fixed carbon combustion was approximately 234 kJ/mol, with a reaction rate constant (k₀) of 3.7 × 10<sup>8</sup> s⁻<sup>1</sup>. The kinetics varied from diffusion-controlled reactions at lower temperatures to first-order or phase-boundary-controlled reactions, and then to Avrami-Erofeev modeled kinetics at higher temperatures, influenced by both temperature and oxygen carrier ratios. This pioneering study provides a comprehensive analysis of the multi-stage kinetics of solid fuel CLC, bridging gaps in current knowledge and laying the groundwork for improved design and efficiency of CLC systems for cleaner energy conversion.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101993"},"PeriodicalIF":5.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.joei.2025.101995
Tianyu Lu , Dan Lin , Yusuf Makarfi Isa , Alexander Kozlov , Maxim Penzik , Xing Xie , Shihong Zhang , Haiping Yang , Bin Li
The effect of oxygen equivalence ratio (ER of 0–9.83 %, corresponding to O2 concentration of 0–3%) on biochar oxidation characteristics under oxidative pyrolysis conditions was investigated in a quartz-tube fluidized-bed reactor. The results showed that under lower ERs and 600 °C, there were two competing oxidation reactions between biochar and oxygen to respectively form CO and CO2, resulting in insignificant changes in biochar oxidation consumption when ER increasing in the range of 1.65–4.94 %. When ER was below 2.29 %, the contents of CO and CO2 both increased rapidly. With ER Further increasing, oxidation of biochar tended to produce more CO2, which was favorable for reducing the biochar oxidation consumption and releasing more heat during oxidative pyrolysis of biomass. When ER was of 4.94 %, the content of CO2 in the produced gas exceeded that of CO. Under low-oxygen concentration (low ER) conditions, the oxidation of biochar tended to consume the combustible C and H in biochar, whereas the O content in biochar was observed to increase. The oxidation etching of biochar also introduced more micropores on the char surface, and altered its surface chemical structures to form more oxygen-containing functional groups. The hydroxyl (-OH) group improved significantly, and the aromatization degree of biochar also increased. The results reported in the study show the prospect to directly obtain optimized structures of active biochar from oxidative pyrolysis of biomass by simply adjusting the oxygen concentration/equivalence ratio.
{"title":"Influence of oxygen equivalence ratio on biochar oxidation characteristics under biomass oxidative pyrolysis conditions in a fluidized-bed reactor","authors":"Tianyu Lu , Dan Lin , Yusuf Makarfi Isa , Alexander Kozlov , Maxim Penzik , Xing Xie , Shihong Zhang , Haiping Yang , Bin Li","doi":"10.1016/j.joei.2025.101995","DOIUrl":"10.1016/j.joei.2025.101995","url":null,"abstract":"<div><div>The effect of oxygen equivalence ratio (ER of 0–9.83 %, corresponding to O<sub>2</sub> concentration of 0–3%) on biochar oxidation characteristics under oxidative pyrolysis conditions was investigated in a quartz-tube fluidized-bed reactor. The results showed that under lower ERs and 600 °C, there were two competing oxidation reactions between biochar and oxygen to respectively form CO and CO<sub>2,</sub> resulting in insignificant changes in biochar oxidation consumption when ER increasing in the range of 1.65–4.94 %. When ER was below 2.29 %, the contents of CO and CO<sub>2</sub> both increased rapidly. With ER Further increasing, oxidation of biochar tended to produce more CO<sub>2</sub>, which was favorable for reducing the biochar oxidation consumption and releasing more heat during oxidative pyrolysis of biomass. When ER was of 4.94 %, the content of CO<sub>2</sub> in the produced gas exceeded that of CO. Under low-oxygen concentration (low ER) conditions, the oxidation of biochar tended to consume the combustible C and H in biochar, whereas the O content in biochar was observed to increase. The oxidation etching of biochar also introduced more micropores on the char surface, and altered its surface chemical structures to form more oxygen-containing functional groups. The hydroxyl (-OH) group improved significantly, and the aromatization degree of biochar also increased. The results reported in the study show the prospect to directly obtain optimized structures of active biochar from oxidative pyrolysis of biomass by simply adjusting the oxygen concentration/equivalence ratio.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101995"},"PeriodicalIF":5.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.joei.2025.101980
Yutong Yang , Bing Sun , Liru Wang , Xiaomei Zhu
With the growing energy demand and the continuous decline of high-quality crude oil resources, the efficient utilization of unconventional resources such as heavy oil has become increasingly important. This aids in improving the stability and sustainability of energy supply. Plasma technology demonstrates significant potential in heavy oil processing due to its unique non-equilibrium and high-energy-density properties, positioning it as an efficient heavy oil conversion approach. Many scholars have made significant efforts to improve the processing capacity of plasma and the yield of target products. This article reviews the recent research advances in the application of plasma technology for the processing of heavy oil and its model compounds. A systematic overview and comparison of different plasma devices and their experimental results is provided. The effects of different phase feedstocks, additives and catalysts on plasma processing performance were analyzed. Provide a research framework and direction for future research. Finally, factors and key challenges limiting its industrialization process are identified, with outlooks and recommendations for the future. The aim is to provide a reference for research in the field of heavy oil processing and promote the application and development of plasma technology in the energy industry.
{"title":"A review of applied plasma processing of heavy oil and its model compounds","authors":"Yutong Yang , Bing Sun , Liru Wang , Xiaomei Zhu","doi":"10.1016/j.joei.2025.101980","DOIUrl":"10.1016/j.joei.2025.101980","url":null,"abstract":"<div><div>With the growing energy demand and the continuous decline of high-quality crude oil resources, the efficient utilization of unconventional resources such as heavy oil has become increasingly important. This aids in improving the stability and sustainability of energy supply. Plasma technology demonstrates significant potential in heavy oil processing due to its unique non-equilibrium and high-energy-density properties, positioning it as an efficient heavy oil conversion approach. Many scholars have made significant efforts to improve the processing capacity of plasma and the yield of target products. This article reviews the recent research advances in the application of plasma technology for the processing of heavy oil and its model compounds. A systematic overview and comparison of different plasma devices and their experimental results is provided. The effects of different phase feedstocks, additives and catalysts on plasma processing performance were analyzed. Provide a research framework and direction for future research. Finally, factors and key challenges limiting its industrialization process are identified, with outlooks and recommendations for the future. The aim is to provide a reference for research in the field of heavy oil processing and promote the application and development of plasma technology in the energy industry.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101980"},"PeriodicalIF":5.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.joei.2025.101986
Ming Lei , Yiteng Zeng , Dikun Hong , Yujie Hu , Wei Liu , Qian Zhang , Lei Zhang
The emission characteristics of gaseous sulfur in the process of gasification is crucial for developing clean coal technology. To study the release behavior of gaseous sulfur during pressurized gasification, this study employed both experimental methods and molecular dynamics simulations. The experimental results indicate that increasing the gasification temperature accelerates the sulfur in coal converting to H2S and COS. And increasing the pressure reduces the release of gaseous sulfur by reducing H2 and CO production. With the rise in CO2 blending ratio, the emission of COS increases and the emission of H2S decreases. Furthermore, the benzothiophene is chosen to examine the release of gaseous sulfur by Reactive Force Field molecular dynamics (ReaxFF MD) method. The calculations exhibit that high temperature facilitates the removal of thiophene sulfur, while the elevated pressure diminishes the main gaseous sulfur emissions and raises the possibility of coal char sulfur formation. The increase of H2O blending ratio contributes to an increase in H and H2, while a decrease in OH and O. And the presence of steam can also provide active hydrogen directly, thereby promoting the migration paths of R-S/C1-4-S→HS→H2S, S→H2S, and weakens the migration paths of R-S→COS, HS→S→COS. The CO2 molecule extends the COS generation path, but the generation of COS remains dependent on the CO molecule to some extent.
{"title":"Investigation on the emission characteristics of gaseous sulfur during pressurized coal gasification by experiment and ReaxFF MD stimulation","authors":"Ming Lei , Yiteng Zeng , Dikun Hong , Yujie Hu , Wei Liu , Qian Zhang , Lei Zhang","doi":"10.1016/j.joei.2025.101986","DOIUrl":"10.1016/j.joei.2025.101986","url":null,"abstract":"<div><div>The emission characteristics of gaseous sulfur in the process of gasification is crucial for developing clean coal technology. To study the release behavior of gaseous sulfur during pressurized gasification, this study employed both experimental methods and molecular dynamics simulations. The experimental results indicate that increasing the gasification temperature accelerates the sulfur in coal converting to H<sub>2</sub>S and COS. And increasing the pressure reduces the release of gaseous sulfur by reducing H<sub>2</sub> and CO production. With the rise in CO<sub>2</sub> blending ratio, the emission of COS increases and the emission of H<sub>2</sub>S decreases. Furthermore, the benzothiophene is chosen to examine the release of gaseous sulfur by Reactive Force Field molecular dynamics (ReaxFF MD) method. The calculations exhibit that high temperature facilitates the removal of thiophene sulfur, while the elevated pressure diminishes the main gaseous sulfur emissions and raises the possibility of coal char sulfur formation. The increase of H<sub>2</sub>O blending ratio contributes to an increase in H and H<sub>2</sub>, while a decrease in OH and O. And the presence of steam can also provide active hydrogen directly, thereby promoting the migration paths of R-S/C<sub>1-4</sub>-S→HS→H<sub>2</sub>S, S→H<sub>2</sub>S, and weakens the migration paths of R-S→COS, HS→S→COS. The CO<sub>2</sub> molecule extends the COS generation path, but the generation of COS remains dependent on the CO molecule to some extent.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101986"},"PeriodicalIF":5.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-07DOI: 10.1016/j.joei.2025.101985
Ruina Li , Quan Hu , Dahai Yang , Feifan Liu , Qingcheng Liu , Hua Yue , Yang Meng
During the fuel injection stage, the temperature and pressure in the cylinder will exceed the fuel critical point and reach the supercritical environment, which has a great influence on the evolution of the interface layer during fuel evaporation. In this study, a molecular dynamics evaporation model was developed for diesel droplets in pure nitrogen and methanol nitrogen at high temperature and high pressure, the variation of molecular clusters in the interface layer of droplet during evaporation was analyzed, and the relationship between droplet evaporation and molecular clusters was revealed. The results show that the initial heating stage of droplets is accelerated and the quasi-static evaporation stage is slowed down by the atmosphere gas mixed with methanol. The concentration of nitrogen and methanol in the interface layer is about 55 % and 158 % respectively at 1100 K, which indicates that the interaction between diesel droplets and methanol is stronger. The change of the interface layer is strongly related to the supercritical transition of droplets. The change of the interface thickness indicates that the dominant mixing mode of droplets changes from evaporation to diffusion The number of molecular clusters increased by 37 %, but the total mass of molecular clusters was little affected by the addition of methanol in the atmosphere, a small number of small molecular clusters have little effect on the evaporation of droplets, while a large number of molecular clusters remain in the interface layer, the interaction between droplet molecules and clusters takes the dominant position after entering the interface layer, which slows down the diffusion of droplet molecules in the interface layer and slows down the evaporation process of fuel droplet.
{"title":"Study on the changes of molecular clusters at the interface layer of diesel droplets in methanol atmosphere under high temperature and high-pressure environment","authors":"Ruina Li , Quan Hu , Dahai Yang , Feifan Liu , Qingcheng Liu , Hua Yue , Yang Meng","doi":"10.1016/j.joei.2025.101985","DOIUrl":"10.1016/j.joei.2025.101985","url":null,"abstract":"<div><div>During the fuel injection stage, the temperature and pressure in the cylinder will exceed the fuel critical point and reach the supercritical environment, which has a great influence on the evolution of the interface layer during fuel evaporation. In this study, a molecular dynamics evaporation model was developed for diesel droplets in pure nitrogen and methanol nitrogen at high temperature and high pressure, the variation of molecular clusters in the interface layer of droplet during evaporation was analyzed, and the relationship between droplet evaporation and molecular clusters was revealed. The results show that the initial heating stage of droplets is accelerated and the quasi-static evaporation stage is slowed down by the atmosphere gas mixed with methanol. The concentration of nitrogen and methanol in the interface layer is about 55 % and 158 % respectively at 1100 K, which indicates that the interaction between diesel droplets and methanol is stronger. The change of the interface layer is strongly related to the supercritical transition of droplets. The change of the interface thickness indicates that the dominant mixing mode of droplets changes from evaporation to diffusion The number of molecular clusters increased by 37 %, but the total mass of molecular clusters was little affected by the addition of methanol in the atmosphere, a small number of small molecular clusters have little effect on the evaporation of droplets, while a large number of molecular clusters remain in the interface layer, the interaction between droplet molecules and clusters takes the dominant position after entering the interface layer, which slows down the diffusion of droplet molecules in the interface layer and slows down the evaporation process of fuel droplet.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101985"},"PeriodicalIF":5.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-04DOI: 10.1016/j.joei.2025.101974
Ümit Ecer , Adem Zengin , Tekin Şahan
Sodium borohydride (NaBH4) is considered one of the most promising materials for hydrogen (H2) production. For this, designing a high-performance and cost-effective catalyst is an important step in developing a sustainable hydrogen source. Here, firstly, cross-linked polymer brushes were grafted on the surface of pumice minerals (P4VP/PMC). Then, Pd nanoparticles were reduced on the surface using the NaBH4 reduction method (Pd-P4VP/PMC). The composition and structure of the catalyst were analyzed using diverse techniques. Response surface methodology (RSM) was used to optimize and model the impact of the main factor interactions during the hydrolysis process. According to the quadratic model obtained, catalyst concentration 2.192 mg/mL; temperature 57.3 °C; NaBH4 concentration 186.6 mM, and NaOH 5.435 wt% were determined to be optimum values using the matrix method. At these values, the maximum hydrogen generation rate (HGR) was 8732.85 mL H2/(gcat. min.) Also, reusability was tested and after five cycles the catalytic activity of Pd-P4VP/PMC was reduced by only ∼30 %. As a result, the synthesized catalyst exhibited relatively low activation energy (26.85 kj/mol) and high HGR (8732.85 mL H2/(gcat. min.)), clearly demonstrating the superiority of Pd-P4VP/PMC as a catalyst for hydrogen generation from hydrolysis of NaBH4.
{"title":"Synthesis and catalytic performance of Pd NPs-doped polymer brushes for optimization and modeling of NaBH4 hydrolysis","authors":"Ümit Ecer , Adem Zengin , Tekin Şahan","doi":"10.1016/j.joei.2025.101974","DOIUrl":"10.1016/j.joei.2025.101974","url":null,"abstract":"<div><div>Sodium borohydride (NaBH<sub>4</sub>) is considered one of the most promising materials for hydrogen (H<sub>2</sub>) production. For this, designing a high-performance and cost-effective catalyst is an important step in developing a sustainable hydrogen source. Here, firstly, cross-linked polymer brushes were grafted on the surface of pumice minerals (P4VP/PMC). Then, Pd nanoparticles were reduced on the surface using the NaBH<sub>4</sub> reduction method (Pd-P4VP/PMC). The composition and structure of the catalyst were analyzed using diverse techniques. Response surface methodology (RSM) was used to optimize and model the impact of the main factor interactions during the hydrolysis process. According to the quadratic model obtained, catalyst concentration 2.192 mg/mL; temperature 57.3 °C; NaBH<sub>4</sub> concentration 186.6 mM, and NaOH 5.435 wt% were determined to be optimum values using the matrix method. At these values, the maximum hydrogen generation rate (HGR) was 8732.85 mL H<sub>2</sub>/(g<sub>cat.</sub> min.) Also, reusability was tested and after five cycles the catalytic activity of Pd-P4VP/PMC was reduced by only ∼30 %. As a result, the synthesized catalyst exhibited relatively low activation energy (26.85 kj/mol) and high HGR (8732.85 mL H<sub>2</sub>/(g<sub>cat.</sub> min.)), clearly demonstrating the superiority of Pd-P4VP/PMC as a catalyst for hydrogen generation from hydrolysis of NaBH<sub>4</sub>.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101974"},"PeriodicalIF":5.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-04DOI: 10.1016/j.joei.2025.101977
Xiao Lin , Meirong Dong , Gangfu Rao , Wei Nie , Guangchi Zhou , Jidong Lu
Volatile combustion is a critical process in solid fuel combustion, requiring a deeper understanding of its carbon conversion mechanisms. This study investigates the synergistic effects of different volatile fraction components CH4, CO, C2H4, and H2 on carbon conversion using a McKenna flat-flame burner. The spatial distribution characteristics of excited-state radicals in flames, namely OH∗, CH∗, and C2∗, were qualitatively measured using image spectroscopy. Additionally, the final product H2O concentration and flame temperature were quantitatively determined through Tunable Diode Laser Absorption Spectroscopy (TDLAS). Combined with chemical kinetics simulations, the study reveals the volatile combustion reaction pathways and the synergistic effects of multi-component co-combustion on carbon conversion. The experimental and kinetic analysis results indicate that H2 promotes CH2 and CH formation, thereby facilitating the production of C2∗ and OH∗. C2H4 enhances C2H formation, which promotes the production of CH∗. Additionally, H2 increases H2O production and raises temperature in flame, while CO inhibits both. While maintaining consistent combustible carbon content in fuel, H2 primarily inhibits the carbon conversion from fuel to CO2 by reducing the pathway proportions involving the main chain reactions HCO and CO, as well as the branch reactions CH2∗ and CH2. In contrast, CO and C2H4 promote carbon conversion to CO2 by increasing the pathway proportions of the branch reactions CH2∗ and CH2. When multi-component co-combustion, the gain in pathway proportion is influenced by both individual component effects and complex synergistic effects, which may result in various outcomes such as synergistic promotion, synergistic inhibition, or a simple additive effect.
{"title":"Carbon conversion mechanism of volatile gas flame based on multi-spectral analysis methods","authors":"Xiao Lin , Meirong Dong , Gangfu Rao , Wei Nie , Guangchi Zhou , Jidong Lu","doi":"10.1016/j.joei.2025.101977","DOIUrl":"10.1016/j.joei.2025.101977","url":null,"abstract":"<div><div>Volatile combustion is a critical process in solid fuel combustion, requiring a deeper understanding of its carbon conversion mechanisms. This study investigates the synergistic effects of different volatile fraction components CH<sub>4</sub>, CO, C<sub>2</sub>H<sub>4</sub>, and H<sub>2</sub> on carbon conversion using a McKenna flat-flame burner. The spatial distribution characteristics of excited-state radicals in flames, namely OH∗, CH∗, and C<sub>2</sub>∗, were qualitatively measured using image spectroscopy. Additionally, the final product H<sub>2</sub>O concentration and flame temperature were quantitatively determined through Tunable Diode Laser Absorption Spectroscopy (TDLAS). Combined with chemical kinetics simulations, the study reveals the volatile combustion reaction pathways and the synergistic effects of multi-component co-combustion on carbon conversion. The experimental and kinetic analysis results indicate that H<sub>2</sub> promotes CH<sub>2</sub> and CH formation, thereby facilitating the production of C<sub>2</sub>∗ and OH∗. C<sub>2</sub>H<sub>4</sub> enhances C<sub>2</sub>H formation, which promotes the production of CH∗. Additionally, H<sub>2</sub> increases H<sub>2</sub>O production and raises temperature in flame, while CO inhibits both. While maintaining consistent combustible carbon content in fuel, H<sub>2</sub> primarily inhibits the carbon conversion from fuel to CO<sub>2</sub> by reducing the pathway proportions involving the main chain reactions HCO and CO, as well as the branch reactions CH<sub>2</sub>∗ and CH<sub>2</sub>. In contrast, CO and C<sub>2</sub>H<sub>4</sub> promote carbon conversion to CO<sub>2</sub> by increasing the pathway proportions of the branch reactions CH<sub>2</sub>∗ and CH<sub>2</sub>. When multi-component co-combustion, the gain in pathway proportion is influenced by both individual component effects and complex synergistic effects, which may result in various outcomes such as synergistic promotion, synergistic inhibition, or a simple additive effect.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101977"},"PeriodicalIF":5.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The conventional fossil fuels which primarily include coal, oil and natural gas are the major source of greenhouse gas emissions (such as methane, carbon dioxide and nitrous oxide) into the atmosphere causing severe health consequences to human population. Different types of renewable energy feedstocks including biomass wastes are being investigated across the world. Out of various techniques for utilizing biomass, the pyrolysis has wide product profiles which can be used in different applications. Likewise, omnipresence of plastic waste, and its tremendous generation and lack of appropriate waste management system is also another environmental issue. Hence, co-pyrolysis (a thermochemical conversion) of biomass and plastic waste, presents an effective solution for the underlined issues as it not only provides a clean source of energy, but is also cost-efficient, easy to use, helps deal with the issue of plastic waste management as well as mitigate the concerns caused by the pyrolysis of single feedstock i.e., biomass. The quality of co-pyrolysis derived bio-oil can further be enhanced by incorporating catalyst. Operating condition of a pyrolysis process depends on the nature of feedstock, requirement of product distribution etc. Thus, optimization of process parameters is essential for making this process successful. Machine learning models can be utilized in the co-pyrolysis process as a tool to overcome the preceding issues by optimizing the process and also helps in process control, yield prediction and real-time monitoring. However, no prior study has conducted an in-depth review of current research scenario related to the machine learning approach in co-pyrolysis process.
{"title":"Co-pyrolysis of biomass and plastic wastes and application of machine learning for modelling of the process: A comprehensive review","authors":"Deepak Bhushan , Sanjeevani Hooda , Prasenjit Mondal","doi":"10.1016/j.joei.2025.101973","DOIUrl":"10.1016/j.joei.2025.101973","url":null,"abstract":"<div><div>The conventional fossil fuels which primarily include coal, oil and natural gas are the major source of greenhouse gas emissions (such as methane, carbon dioxide and nitrous oxide) into the atmosphere causing severe health consequences to human population. Different types of renewable energy feedstocks including biomass wastes are being investigated across the world. Out of various techniques for utilizing biomass, the pyrolysis has wide product profiles which can be used in different applications. Likewise, omnipresence of plastic waste, and its tremendous generation and lack of appropriate waste management system is also another environmental issue. Hence, co-pyrolysis (a thermochemical conversion) of biomass and plastic waste, presents an effective solution for the underlined issues as it not only provides a clean source of energy, but is also cost-efficient, easy to use, helps deal with the issue of plastic waste management as well as mitigate the concerns caused by the pyrolysis of single feedstock i.e., biomass. The quality of co-pyrolysis derived bio-oil can further be enhanced by incorporating catalyst. Operating condition of a pyrolysis process depends on the nature of feedstock, requirement of product distribution etc. Thus, optimization of process parameters is essential for making this process successful. Machine learning models can be utilized in the co-pyrolysis process as a tool to overcome the preceding issues by optimizing the process and also helps in process control, yield prediction and real-time monitoring. However, no prior study has conducted an in-depth review of current research scenario related to the machine learning approach in co-pyrolysis process.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"119 ","pages":"Article 101973"},"PeriodicalIF":5.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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