The distribution of pyrolysis products from aromatic model compounds in coal catalyzed by Ca(OH)2 was investigated at the molecular level. The composition and relative abundance of the pyrolysis products from coal were analyzed using Py-GC/MS. The rapid pyrolysis products of coal at 600 °C consisted of phenols (15.94 %), non-phenolic oxygenated compounds (25.31 %), aliphatics (49.03 %), aromatic compounds (21.74 %), and other compounds (0.03 %). Six representative aromatic model compounds (2-methoxy-4-methylphenol, p-cresol, 2,4-dimethylphenol, o-cresol, guaiacol, and catechol) were selected. The pyrolysis process of model compounds was primarily the cleavage of C-O and C-C bonds, which resulted in the formation of methoxy and methyl radicals. The results revealed that Ca(OH)2 undergoes acid-base reactions with -OH, thereby increasing the stability of the model compounds. Notably, the impact of Ca(OH)2 on the composition and distribution of pyrolysis products was significantly more pronounced in aromatic compounds containing both -OCH3 and -OH compared to those containing solely -OH. The formation pathways of pyrolysis products involving guaiacol and Ca(OH)2 were elucidated through density functional theory (DFT) calculations, demonstrating that Ca(OH)2 could facilitate more free radicals release and the conversion of model compounds. This study contributes to the understanding of the transformation of aromatic compounds during coal pyrolysis at the molecular level.
{"title":"Exploring the catalytic conversion of aromatic model compounds of coal pyrolysis over Ca(OH)2","authors":"Xiaoguo Zhang, Yun Yang, Wei Lu, Danni Ren, Shenfu Yuan","doi":"10.1016/j.joei.2024.101850","DOIUrl":"10.1016/j.joei.2024.101850","url":null,"abstract":"<div><div>The distribution of pyrolysis products from aromatic model compounds in coal catalyzed by Ca(OH)<sub>2</sub> was investigated at the molecular level. The composition and relative abundance of the pyrolysis products from coal were analyzed using Py-GC/MS. The rapid pyrolysis products of coal at 600 °C consisted of phenols (15.94 %), non-phenolic oxygenated compounds (25.31 %), aliphatics (49.03 %), aromatic compounds (21.74 %), and other compounds (0.03 %). Six representative aromatic model compounds (2-methoxy-4-methylphenol, p-cresol, 2,4-dimethylphenol, o-cresol, guaiacol, and catechol) were selected. The pyrolysis process of model compounds was primarily the cleavage of C-O and C-C bonds, which resulted in the formation of methoxy and methyl radicals. The results revealed that Ca(OH)<sub>2</sub> undergoes acid-base reactions with -OH, thereby increasing the stability of the model compounds. Notably, the impact of Ca(OH)<sub>2</sub> on the composition and distribution of pyrolysis products was significantly more pronounced in aromatic compounds containing both -OCH<sub>3</sub> and -OH compared to those containing solely -OH. The formation pathways of pyrolysis products involving guaiacol and Ca(OH)<sub>2</sub> were elucidated through density functional theory (DFT) calculations, demonstrating that Ca(OH)<sub>2</sub> could facilitate more free radicals release and the conversion of model compounds. This study contributes to the understanding of the transformation of aromatic compounds during coal pyrolysis at the molecular level.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101850"},"PeriodicalIF":5.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422255","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}
Existing online monitoring system for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), technically named Thermal Desorption-Gas Chromatography-Tunable Laser Ionization-Time of Flight Mass Spectrometry (TD-GC-TLI-TOFMS), has been applied in several incinerators in China. TD-GC-TLI-TOFMS can realize rapid detection of PCDD/Fs emissions from incineration sources. However, the long-term measurement of unclean flue gas will pollute the instruments in TD-GC-TLI-TOFMS, and interfere with the peak output of the target 1,2,4-trichlorobenzene (1,2,4-TrCBz). In this study, Deans switch (DS) was utilized for the first time in an online monitoring system for PCDD/Fs to separate 1,2,4-TrCBz signal from impurity signals, which improved the anti-interference capability of the system. Laboratory standard gas experiments showed that after adding a DS device between GC and TLI pulse valve, when the pressure set in DS was 4 psi and switched before or near the peak output of 1,2,4-TrCBz, the change of 1,2,4-TrCBz signal intensity was minimal. The impurities near the target peak were removed, and TLI-TOFMS was highly stable during continuous measurement. Moreover, the maximum intensity peak time of 1,2,4-TrCBz was stable after using DS in different switching time intervals. When connecting DS to TD-GC-TLI-TOFMS for field validation on the tail flue gas of a municipal solid waste incinerator (MSWI), results showed that a better 1,2,4-TrCBz signal could be obtained with a 69.52 % reduction of impurity peaks at the moments closer to the target peak. Furthermore, DS improved the sensitivity of the system to low concentration variations of 1,2,4-TrCBz in the flue gas. The robust system developed in this study can be better applied to incineration factories with poor combustion or suboptimal purification technology, facilitating online PCDD/Fs monitoring.
{"title":"Robust online monitoring system for PCDD/Fs in a full-scale MSWI by Deans switch: Efficiently separation and purification","authors":"Lulu Dong , Wenqian Jiang , Minghui Tang , Kaicheng Wu , Shijian Xiong , Shengyong Lu , Fanjie Shang","doi":"10.1016/j.joei.2024.101852","DOIUrl":"10.1016/j.joei.2024.101852","url":null,"abstract":"<div><div>Existing online monitoring system for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), technically named Thermal Desorption-Gas Chromatography-Tunable Laser Ionization-Time of Flight Mass Spectrometry (TD-GC-TLI-TOFMS), has been applied in several incinerators in China. TD-GC-TLI-TOFMS can realize rapid detection of PCDD/Fs emissions from incineration sources. However, the long-term measurement of unclean flue gas will pollute the instruments in TD-GC-TLI-TOFMS, and interfere with the peak output of the target 1,2,4-trichlorobenzene (1,2,4-TrCBz). In this study, Deans switch (DS) was utilized for the first time in an online monitoring system for PCDD/Fs to separate 1,2,4-TrCBz signal from impurity signals, which improved the anti-interference capability of the system. Laboratory standard gas experiments showed that after adding a DS device between GC and TLI pulse valve, when the pressure set in DS was 4 psi and switched before or near the peak output of 1,2,4-TrCBz, the change of 1,2,4-TrCBz signal intensity was minimal. The impurities near the target peak were removed, and TLI-TOFMS was highly stable during continuous measurement. Moreover, the maximum intensity peak time of 1,2,4-TrCBz was stable after using DS in different switching time intervals. When connecting DS to TD-GC-TLI-TOFMS for field validation on the tail flue gas of a municipal solid waste incinerator (MSWI), results showed that a better 1,2,4-TrCBz signal could be obtained with a 69.52 % reduction of impurity peaks at the moments closer to the target peak. Furthermore, DS improved the sensitivity of the system to low concentration variations of 1,2,4-TrCBz in the flue gas. The robust system developed in this study can be better applied to incineration factories with poor combustion or suboptimal purification technology, facilitating online PCDD/Fs monitoring.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101852"},"PeriodicalIF":5.6,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422256","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 : 2024-10-03DOI: 10.1016/j.joei.2024.101854
Yijie Zeng , Hyun-Yeong Jo , Seung-Mo Kim , Byoung-Hwa Lee , Chung-Hwan Jeon
Ammonia co-firing is increasingly regarded as an effective strategy to reduce CO2 emissions in coal-fired boilers. In this study, we introduce and evaluate two innovative fuel blending methods for ammonia-coal co-firing in a commercial 500 MW utility boiler: burner blending and in-boiler blending. Using computational fluid dynamics simulations, we investigated the effects of 20 % ammonia co-firing on heat transfer efficiency, fuel burnout rate, and pollutant emissions. The results show that while ammonia co-firing effectively reduces CO2 emissions, it also leads to decreases in the furnace and furnace exit-gas temperatures due to the lower flame temperature and increased moisture production. Specifically, the total heat absorption by the water walls and heat exchangers decreased by 4.58 % in the burner blending method and 2.27 % in the in-boiler blending method compared to that with pure coal combustion. Although ammonia co-firing suppresses the generation of thermal NO, overall NO emissions increase significantly due to the substantial release of fuel NO. However, the in-boiler blending method demonstrated superior NO reduction, reducing NO emissions by 13.48 ppm compared to the burner blending method. In addition, the in-boiler blending method showed better combustion stability, achieving faster ignition and reducing the amount of unburned carbon in fly ash by 0.97 %, compared to that with the burner blending method. This is likely due to the higher concentration of combustible gases near the burner in the in-boiler blending system. These findings indicate that the in-boiler blending method is more effective than the burner blending method for ammonia-coal co-firing in a 500 MW utility boiler. This provides valuable insights into the implementation of ammonia co-firing in commercial boilers as part of efforts to achieve carbon neutrality.
{"title":"NH3 co-firing strategy in 500 MW tangential utility boiler: Impact of blending methods","authors":"Yijie Zeng , Hyun-Yeong Jo , Seung-Mo Kim , Byoung-Hwa Lee , Chung-Hwan Jeon","doi":"10.1016/j.joei.2024.101854","DOIUrl":"10.1016/j.joei.2024.101854","url":null,"abstract":"<div><div>Ammonia co-firing is increasingly regarded as an effective strategy to reduce CO<sub>2</sub> emissions in coal-fired boilers. In this study, we introduce and evaluate two innovative fuel blending methods for ammonia-coal co-firing in a commercial 500 MW utility boiler: burner blending and in-boiler blending. Using computational fluid dynamics simulations, we investigated the effects of 20 % ammonia co-firing on heat transfer efficiency, fuel burnout rate, and pollutant emissions. The results show that while ammonia co-firing effectively reduces CO<sub>2</sub> emissions, it also leads to decreases in the furnace and furnace exit-gas temperatures due to the lower flame temperature and increased moisture production. Specifically, the total heat absorption by the water walls and heat exchangers decreased by 4.58 % in the burner blending method and 2.27 % in the in-boiler blending method compared to that with pure coal combustion. Although ammonia co-firing suppresses the generation of thermal NO, overall NO emissions increase significantly due to the substantial release of fuel NO. However, the in-boiler blending method demonstrated superior NO reduction, reducing NO emissions by 13.48 ppm compared to the burner blending method. In addition, the in-boiler blending method showed better combustion stability, achieving faster ignition and reducing the amount of unburned carbon in fly ash by 0.97 %, compared to that with the burner blending method. This is likely due to the higher concentration of combustible gases near the burner in the in-boiler blending system. These findings indicate that the in-boiler blending method is more effective than the burner blending method for ammonia-coal co-firing in a 500 MW utility boiler. This provides valuable insights into the implementation of ammonia co-firing in commercial boilers as part of efforts to achieve carbon neutrality.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101854"},"PeriodicalIF":5.6,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422259","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 : 2024-10-03DOI: 10.1016/j.joei.2024.101853
Subhashini, Tarak Mondal
Plastic waste management has become a vitally important environmental and economic concern for researchers and technologists worldwide. Currently, catalytic pyrolysis of plastic waste emerged as a promising plastic waste management technique, further aiding the full-scale development of an alternate innovation to convert plastic waste into fuel (liquid oil) energy. Lately, zeolites have been one of the most suitable and versatile catalysts in converting plastic waste into fuel grade hydrocarbons via catalytic pyrolysis. The present work exhibits an attempt to synthesize and study the performance of a hierarchical ZSM-5 in a fixed bed reactor to convert the real-world (LDPE, HDPE, PP and PS) plastic wastes into higher quality fuel grade liquid oil. The hierarchical ZSM-5 catalyst having both mesopores and micropores (dual porosity) in its framework is synthesized by using a single organic template i.e., 10 % tetra propylammonium hydroxide (TPAOH). The catalyst performance study displays remarkable selectivity and increase in the yield of the aromatic component in the liquid oil obtained from different plastic wastes. The results indicate that presence of hierarchical catalyst has exceptionally lowered the reaction temperature in the range of 400–430 °C and increased the liquid oil yield in comparison with that of the thermal pyrolysis. Also, the obtained liquid oils have comparable fuel properties with that of kerosene and diesel.
{"title":"Probing the influence of synthesized hierarchical ZSM-5 catalyst in ex-situ catalytic conversion of real-world plastic waste into aromatic rich liquid oil","authors":"Subhashini, Tarak Mondal","doi":"10.1016/j.joei.2024.101853","DOIUrl":"10.1016/j.joei.2024.101853","url":null,"abstract":"<div><div>Plastic waste management has become a vitally important environmental and economic concern for researchers and technologists worldwide. Currently, catalytic pyrolysis of plastic waste emerged as a promising plastic waste management technique, further aiding the full-scale development of an alternate innovation to convert plastic waste into fuel (liquid oil) energy. Lately, zeolites have been one of the most suitable and versatile catalysts in converting plastic waste into fuel grade hydrocarbons via catalytic pyrolysis. The present work exhibits an attempt to synthesize and study the performance of a hierarchical ZSM-5 in a fixed bed reactor to convert the real-world (LDPE, HDPE, PP and PS) plastic wastes into higher quality fuel grade liquid oil. The hierarchical ZSM-5 catalyst having both mesopores and micropores (dual porosity) in its framework is synthesized by using a single organic template i.e., 10 % tetra propylammonium hydroxide (TPAOH). The catalyst performance study displays remarkable selectivity and increase in the yield of the aromatic component in the liquid oil obtained from different plastic wastes. The results indicate that presence of hierarchical catalyst has exceptionally lowered the reaction temperature in the range of 400–430 °C and increased the liquid oil yield in comparison with that of the thermal pyrolysis. Also, the obtained liquid oils have comparable fuel properties with that of kerosene and diesel.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101853"},"PeriodicalIF":5.6,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422262","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}
Hydrothermal liquefaction (HTL) possesses an outstanding biomass thermal conversion technology for producing biocrude oil (BO). Here, cassava rhizome (CR) was converted into BO via catalytic HTL using 1.0–10.0 wt% of K2CO3 and Na2CO3 with water-soluble product (WSP) recirculation at 275 °C for 15 min. The catalysts and WSP recirculation could enhance the BO fuel properties. The dominant BO yield of 38.00 and 34.80 wt% and HHV of 25.42 and 25.92 Mj/kg were derived using 4.0 wt% of K2CO3 and Na2CO3, respectively. Chemical compositions of the BO were principally phenols and hydrocarbons, which can be further upgraded and fractionated into alternative biofuels. On the other hand, the mass yield and HHV of the hydrochar (HC) co-product were reduced by the alkaline catalysts, while being maintained by WSP recirculation. The HC fuel characterization elucidated that the HC can be used as an alternative to coal. Furthermore, WSP characterization determined that organic acids were the major composition of the WSP. Thus, WSP recirculation can enhance CR decomposition according to the proposed reaction mechanism. These results indicate that the alkaline application and WSP recirculation constitute a dominant method for enhancing biofuel production via HTL.
{"title":"Enhancing biofuel production in hydrothermal liquefaction of cassava rhizome through alkaline catalyst application and water-soluble product recirculation","authors":"Parinvadee Chukaew , Sanchai Kuboon , Wasawat Kraithong , Bunyarit Panyapinyopol , Vorapot Kanokkantapong , Jakkapon Phanthuwongpakdee , Kamonwat Nakason","doi":"10.1016/j.joei.2024.101848","DOIUrl":"10.1016/j.joei.2024.101848","url":null,"abstract":"<div><div>Hydrothermal liquefaction (HTL) possesses an outstanding biomass thermal conversion technology for producing biocrude oil (BO). Here, cassava rhizome (CR) was converted into BO via catalytic HTL using 1.0–10.0 wt% of K<sub>2</sub>CO<sub>3</sub> and Na<sub>2</sub>CO<sub>3</sub> with water-soluble product (WSP) recirculation at 275 °C for 15 min. The catalysts and WSP recirculation could enhance the BO fuel properties. The dominant BO yield of 38.00 and 34.80 wt% and HHV of 25.42 and 25.92 Mj/kg were derived using 4.0 wt% of K<sub>2</sub>CO<sub>3</sub> and Na<sub>2</sub>CO<sub>3</sub>, respectively. Chemical compositions of the BO were principally phenols and hydrocarbons, which can be further upgraded and fractionated into alternative biofuels. On the other hand, the mass yield and HHV of the hydrochar (HC) co-product were reduced by the alkaline catalysts, while being maintained by WSP recirculation. The HC fuel characterization elucidated that the HC can be used as an alternative to coal. Furthermore, WSP characterization determined that organic acids were the major composition of the WSP. Thus, WSP recirculation can enhance CR decomposition according to the proposed reaction mechanism. These results indicate that the alkaline application and WSP recirculation constitute a dominant method for enhancing biofuel production via HTL.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101848"},"PeriodicalIF":5.6,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422260","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 hydrothermal gradient extraction process based on the hemicellulose constituent units is important for obtaining high quality hemicellulose products. The hydrothermal extraction of sawdust hemicellulose was performed under both non-isothermal and isothermal operations using a flow-through reactor for investigating the extraction patterns. The results show that there were significant differences in the major forms of hemicellulose units at different extraction stages. For glucose, xylose, and galactose units, the selectivity of oligomeric form decreased gradually with increasing temperature, whereas it decreased and then increased under thermostatic operation. The selectivity of the mannose oligomeric form decreased and then increased in both operation modes, reaching a trough at 170 °C (96.81 %) and 60 min (55.21 %), respectively. The molecular weight of extracted hemicelluloses were mainly distributed below 70,000 Da, and gradually decreased with temperature, but increased with time. The results contribute to the quantitative and qualitative understanding of the hemicellulose gradient extraction process.
基于半纤维素组成单元的水热梯度萃取工艺对于获得高质量的半纤维素产品非常重要。为研究萃取模式，使用流动反应器在非等温和等温操作下对锯末半纤维素进行了水热萃取。结果表明，在不同提取阶段，半纤维素单元的主要形式存在显著差异。对于葡萄糖、木糖和半乳糖单元，低聚物形式的选择性随着温度的升高而逐渐降低，而在恒温操作下，低聚物形式的选择性先降低后升高。在两种操作模式下，甘露糖低聚物的选择性先降低后升高，分别在 170 °C 时（96.81%）和 60 分钟时（55.21%）达到低谷。提取的半纤维素分子量主要分布在 70,000 Da 以下，随温度的升高而逐渐降低，但随时间的延长而逐渐升高。这些结果有助于对半纤维素梯度萃取过程的定量和定性认识。
{"title":"Study on the hydrothermal gradient extraction of hemicellulose by a flow-through reactor","authors":"Jing-Xian Wang , Da-Meng Wang , Wen-Long Xu , Xuan-Jie Zou , Pei-Jie Zong , Hao-Zhe Zhang , Yan-Chao Shang , Jia-Lin Zhao , Yi-Fan Wu , Ying-Yun Qiao , Yuan-Yu Tian","doi":"10.1016/j.joei.2024.101855","DOIUrl":"10.1016/j.joei.2024.101855","url":null,"abstract":"<div><div>The hydrothermal gradient extraction process based on the hemicellulose constituent units is important for obtaining high quality hemicellulose products. The hydrothermal extraction of sawdust hemicellulose was performed under both non-isothermal and isothermal operations using a flow-through reactor for investigating the extraction patterns. The results show that there were significant differences in the major forms of hemicellulose units at different extraction stages. For glucose, xylose, and galactose units, the selectivity of oligomeric form decreased gradually with increasing temperature, whereas it decreased and then increased under thermostatic operation. The selectivity of the mannose oligomeric form decreased and then increased in both operation modes, reaching a trough at 170 °C (96.81 %) and 60 min (55.21 %), respectively. The molecular weight of extracted hemicelluloses were mainly distributed below 70,000 Da, and gradually decreased with temperature, but increased with time. The results contribute to the quantitative and qualitative understanding of the hemicellulose gradient extraction process.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101855"},"PeriodicalIF":5.6,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422257","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 : 2024-09-28DOI: 10.1016/j.joei.2024.101845
Shuqiang Liu , Jie Zhang , Jingyu Xue , Mingliang Chen , Leyang Dai , Zibin Yin , Yaoqi Kang
Due to the increasingly stringent emission regulations and the rising call for energy saving and emission reduction, efficient and clean combustion in internal combustion engines have become a research priority. However, the in-cylinder spray combustion process is complex and variable due to a variety of factors. Spray combustion, as a key segment of combustion in internal combustion engines, plays a key role in the efficient and clean combustion of internal combustion engines. The optical test device can truly observe the spray combustion in the cylinder of an internal combustion engine by equipping with an optical window. This paper focuses on the study of internal combustion engine optics, and reviews the current major optical test devices, optical detection methods, and spray combustion characteristics of three different alternative fuels. Firstly, the paper reviews three commonly used optical test devices, namely, CVCB, RCM and optical engine, and their studies on laminar flame, ignition delay and flash spray. Subsequently, the paper summarizes the spray combustion characteristic parameters and nine commonly used optical test methods that are well suited to determine spray morphology, concentration field, velocity field, combustion characteristics and intermediate composition. Finally, the paper summarizes the spray combustion characteristics of three alternative fuels.
{"title":"Optical test devices and methods for internal combustion engines and optical studies on spray combustion characteristics for three different alternative fuels: A review","authors":"Shuqiang Liu , Jie Zhang , Jingyu Xue , Mingliang Chen , Leyang Dai , Zibin Yin , Yaoqi Kang","doi":"10.1016/j.joei.2024.101845","DOIUrl":"10.1016/j.joei.2024.101845","url":null,"abstract":"<div><div>Due to the increasingly stringent emission regulations and the rising call for energy saving and emission reduction, efficient and clean combustion in internal combustion engines have become a research priority. However, the in-cylinder spray combustion process is complex and variable due to a variety of factors. Spray combustion, as a key segment of combustion in internal combustion engines, plays a key role in the efficient and clean combustion of internal combustion engines. The optical test device can truly observe the spray combustion in the cylinder of an internal combustion engine by equipping with an optical window. This paper focuses on the study of internal combustion engine optics, and reviews the current major optical test devices, optical detection methods, and spray combustion characteristics of three different alternative fuels. Firstly, the paper reviews three commonly used optical test devices, namely, CVCB, RCM and optical engine, and their studies on laminar flame, ignition delay and flash spray. Subsequently, the paper summarizes the spray combustion characteristic parameters and nine commonly used optical test methods that are well suited to determine spray morphology, concentration field, velocity field, combustion characteristics and intermediate composition. Finally, the paper summarizes the spray combustion characteristics of three alternative fuels.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101845"},"PeriodicalIF":5.6,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357004","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 : 2024-09-27DOI: 10.1016/j.joei.2024.101847
Rui Jiang, Zhenwu Miao, Laihong Shen
Integrated carbon capture and in-situ methane dry reforming (ICCU-DRM) is a promising technology for chemical looping transformation, this process involves the sequential switching of feedstocks within a single reactor, allowing CO2 capture to occur before methane dry reforming without direct CO2-CH4 contact. However, a significant challenge in the ICCU-DRM process is the disparity between the optimal temperatures required for carbon capture and dry reforming, with the latter necessitating considerably higher temperatures. This could lead to substantial CO2 losses when the reaction temperature is elevated to the optimal level for dry reforming. To address this issue and improve CO2 conversion efficiency, this study explores K doping in synthesizing a dual-functional material, NiCa1.6K0.4@Al2O3, through extrusion-spheronization. The synthesized material exhibits a stable pore structure and a large internal surface area, crucial for enhancing CO2 capture. The optimum temperature for DRM is around 800 °C. Notably, the formation of K2Ca(CO3)2 during the calcination of NiCa1.6K0.4@Al2O3, with a thermal decomposition temperature of approximately 800 °C, plays a crucial role in minimizing CO2 release during the heating process, thereby significantly improving the CO2 conversion. To evaluate the impact of K doping on the material, the samples were subjected to carbon capture at 650 °C and dry reforming of methane at 750 °C. The results showed that the CO2 conversion rate of NiCa1.6K0.4@Al2O3 reached 52.8 %, compared to only 18.9 % for NiCa2@Al2O3 under the same conditions. Moreover, this study also investigates the impact of carbon capture temperature, dry reforming temperature, and catalytic metal loading on the performance of the ICCU-DRM process.
集成碳捕集与原位甲烷干重整（ICCU-DRM）是一种很有前景的化学循环转化技术，该工艺涉及在单个反应器内按顺序切换原料，允许在甲烷干重整之前进行二氧化碳捕集，而不直接接触二氧化碳和甲烷。然而，ICCU-DRM 工艺面临的一个重大挑战是碳捕集和干重整所需的最佳温度之间存在差异，后者需要更高的温度。当反应温度升高到干重整的最佳温度时，可能会导致大量二氧化碳损失。为解决这一问题并提高二氧化碳转化效率，本研究探讨了通过挤压-球化掺杂 K 合成双功能材料 NiCa1.6K0.4@Al2O3。合成的材料具有稳定的孔隙结构和较大的内表面积，这对提高二氧化碳捕集率至关重要。DRM 的最佳温度约为 800 ℃。值得注意的是，NiCa1.6K0.4@Al2O3 的煅烧过程中会形成 K2Ca(CO3)2，其热分解温度约为 800 °C，这对最大限度地减少加热过程中的二氧化碳释放起到了关键作用，从而显著提高了二氧化碳转化率。为了评估 K 掺杂对材料的影响，对样品进行了 650 °C 的碳捕集和 750 °C 的甲烷干转化试验。结果表明，在相同条件下，NiCa1.6K0.4@Al2O3 的二氧化碳转化率达到 52.8%，而 NiCa2@Al2O3 的转化率仅为 18.9%。此外，本研究还探讨了碳捕集温度、干重整温度和催化金属负载对 ICCU-DRM 工艺性能的影响。
{"title":"Study on K-modified Ca-based dual-functional materials for carbon capture and in-situ methane dry reforming","authors":"Rui Jiang, Zhenwu Miao, Laihong Shen","doi":"10.1016/j.joei.2024.101847","DOIUrl":"10.1016/j.joei.2024.101847","url":null,"abstract":"<div><div>Integrated carbon capture and in-situ methane dry reforming (ICCU-DRM) is a promising technology for chemical looping transformation, this process involves the sequential switching of feedstocks within a single reactor, allowing CO<sub>2</sub> capture to occur before methane dry reforming without direct CO<sub>2</sub>-CH<sub>4</sub> contact. However, a significant challenge in the ICCU-DRM process is the disparity between the optimal temperatures required for carbon capture and dry reforming, with the latter necessitating considerably higher temperatures. This could lead to substantial CO<sub>2</sub> losses when the reaction temperature is elevated to the optimal level for dry reforming. To address this issue and improve CO<sub>2</sub> conversion efficiency, this study explores K doping in synthesizing a dual-functional material, NiCa<sub>1.6</sub>K<sub>0.4</sub>@Al<sub>2</sub>O<sub>3</sub>, through extrusion-spheronization. The synthesized material exhibits a stable pore structure and a large internal surface area, crucial for enhancing CO<sub>2</sub> capture. The optimum temperature for DRM is around 800 °C. Notably, the formation of K<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub> during the calcination of NiCa<sub>1.6</sub>K<sub>0.4</sub>@Al<sub>2</sub>O<sub>3</sub>, with a thermal decomposition temperature of approximately 800 °C, plays a crucial role in minimizing CO<sub>2</sub> release during the heating process, thereby significantly improving the CO<sub>2</sub> conversion. To evaluate the impact of K doping on the material, the samples were subjected to carbon capture at 650 °C and dry reforming of methane at 750 °C. The results showed that the CO<sub>2</sub> conversion rate of NiCa<sub>1.6</sub>K<sub>0.4</sub>@Al<sub>2</sub>O<sub>3</sub> reached 52.8 %, compared to only 18.9 % for NiCa<sub>2</sub>@Al<sub>2</sub>O<sub>3</sub> under the same conditions. Moreover, this study also investigates the impact of carbon capture temperature, dry reforming temperature, and catalytic metal loading on the performance of the ICCU-DRM process.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101847"},"PeriodicalIF":5.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535937","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 : 2024-09-27DOI: 10.1016/j.joei.2024.101843
Mengfan Yuan , Wenkun Zhu , Hongliang Qi , Xingyi Wang , Lei Zhang , Yupeng Li , Rui Sun
A transient ignition model employing a reduced chemical mechanism was developed to investigate the ignition characteristics and the gas-phase flame evolution of pulverized coal particles. The chemical percolation devolatilization (CPD) model was chosen to simulate the devolatilization process, and its accuracy was validated using a high-temperature entrained-flow reactor. Additionally, a novel method was introduced to cross-validate the single-particle simulation results with real-time OH-PLIF experimental measurements of particle streams, particularly at a large particle spacing ratio. The ignition mode was determined using the ignition delay time and volatile burnout time. Results show that as the oxygen volume fraction increases from 5% to 50% at a temperature of 1800 K, the ignition mode transitions from homogeneous ignition (GI) to heterogeneous ignition (HI). Notably, the same ignition mode was observed regardless of whether GI was defined using gas-phase temperature or OH levels. In the homo-heterogeneous ignition mode, the gas-phase flame intensity, characterized by OH levels, increases rapidly, then decreases, and re-increases slightly. The sequence of gas-phase reactions initiates with volatile combustion, followed by the co-combustion of residual volatiles and newly generated CO, and culminates in the combustion of CO itself. Online experimental findings confirmed that CO originates from char oxidation. Throughout this process, the gas-phase flame front extends outward until the volatiles are consumed.
为了研究煤粉颗粒的着火特性和气相火焰演化，开发了一种采用还原化学机制的瞬态着火模型。选择化学渗滤脱碳（CPD）模型来模拟脱碳过程，并使用高温内流反应器验证了其准确性。此外，还引入了一种新方法，将单颗粒模拟结果与颗粒流的实时 OH-PLIF 实验测量结果进行交叉验证，尤其是在颗粒间距比较大的情况下。利用点火延迟时间和挥发燃烧时间确定了点火模式。结果表明，在温度为 1800 K 时，当氧气体积分数从 5% 增加到 50% 时，点火模式从均质点火 (GI) 过渡到异质点火 (HI)。值得注意的是，无论使用气相温度还是羟基水平来定义 GI，都能观察到相同的点火模式。在同质异相点火模式下，气相火焰强度（以羟基水平为特征）会迅速增加，然后减弱，最后再略微增加。气相反应的顺序由挥发物燃烧开始，然后是残余挥发物和新生成的 CO 共同燃烧，最后是 CO 本身的燃烧。在线实验结果证实，CO 源自炭氧化。在整个过程中，气相火焰前沿一直向外延伸，直到挥发物消耗殆尽。
{"title":"Numerical analysis of the ignition and gas-phase flame evolution of pulverized coal based on online experimental diagnostics","authors":"Mengfan Yuan , Wenkun Zhu , Hongliang Qi , Xingyi Wang , Lei Zhang , Yupeng Li , Rui Sun","doi":"10.1016/j.joei.2024.101843","DOIUrl":"10.1016/j.joei.2024.101843","url":null,"abstract":"<div><div>A transient ignition model employing a reduced chemical mechanism was developed to investigate the ignition characteristics and the gas-phase flame evolution of pulverized coal particles. The chemical percolation devolatilization (CPD) model was chosen to simulate the devolatilization process, and its accuracy was validated using a high-temperature entrained-flow reactor. Additionally, a novel method was introduced to cross-validate the single-particle simulation results with real-time OH-PLIF experimental measurements of particle streams, particularly at a large particle spacing ratio. The ignition mode was determined using the ignition delay time and volatile burnout time. Results show that as the oxygen volume fraction increases from 5% to 50% at a temperature of 1800 K, the ignition mode transitions from homogeneous ignition (GI) to heterogeneous ignition (HI). Notably, the same ignition mode was observed regardless of whether GI was defined using gas-phase temperature or OH levels. In the homo-heterogeneous ignition mode, the gas-phase flame intensity, characterized by OH levels, increases rapidly, then decreases, and re-increases slightly. The sequence of gas-phase reactions initiates with volatile combustion, followed by the co-combustion of residual volatiles and newly generated CO, and culminates in the combustion of CO itself. Online experimental findings confirmed that CO originates from char oxidation. Throughout this process, the gas-phase flame front extends outward until the volatiles are consumed.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101843"},"PeriodicalIF":5.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422258","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 : 2024-09-27DOI: 10.1016/j.joei.2024.101846
Liu Leilei , Niu Zhenze , Feng Hongqing , Han Xinlu , Zhang Shuo , Wang Changhui
When both isopropanol and n-propanol are incorporated, the utilization of propanol as a fuel substitute (or a gasoline additive) presents promising potential for enhancing the combustion efficiency and thermal performance in compact, turbocharged, direct-injection gasoline engines upon blending. However, the complexity of the laminar combustion behavior of propanol-blended gasoline has yet to be fully investigated, as current coupling mechanisms are insufficiently sophisticated to precisely mirror the complex experimental conditions.
This study establishes a testbed specifically designed for measuring laminar burning velocity (LBV) using the heat flux method. This setup is employed to measure the LBV of pure n-heptane and isooctane, as well as the LBV of the gasoline surrogate fuel TRF with two distinct blend ratios. Additionally, it measures the LBV of propanol and its blends with TRF. The research findings reveal that isooctane demonstrates a heightened sensitivity to fuel preheating temperature, whereas the toluene proportion in TRF fuels exerts the most pronounced influence on combustion behavior. At an equivalence ratio of 1.1, the LBV of n-propanol differs from that of its isomer, isopropanol, by 4.65 cm/s. Notably, the LBV exhibits a discernible upward trend, corresponding to the increasing proportion of toluene in the blended fuel. Furthermore, there is a pronounced distinction in LBV among the propanol isomers, with blended TRF occupying an intermediate position between pure propanol and TRF. After the enhancement of the mechanism based on experimental benchmarks of LBV, a rigorous validation process demonstrated a substantial improvement in the alignment between simulated outcomes and empirical LBV measurements.
{"title":"Study on laminar combustion characteristics and the optimization of the coupling mechanism in a mixture of propanol and gasoline","authors":"Liu Leilei , Niu Zhenze , Feng Hongqing , Han Xinlu , Zhang Shuo , Wang Changhui","doi":"10.1016/j.joei.2024.101846","DOIUrl":"10.1016/j.joei.2024.101846","url":null,"abstract":"<div><div>When both isopropanol and n-propanol are incorporated, the utilization of propanol as a fuel substitute (or a gasoline additive) presents promising potential for enhancing the combustion efficiency and thermal performance in compact, turbocharged, direct-injection gasoline engines upon blending. However, the complexity of the laminar combustion behavior of propanol-blended gasoline has yet to be fully investigated, as current coupling mechanisms are insufficiently sophisticated to precisely mirror the complex experimental conditions.</div><div>This study establishes a testbed specifically designed for measuring laminar burning velocity (LBV) using the heat flux method. This setup is employed to measure the LBV of pure n-heptane and isooctane, as well as the LBV of the gasoline surrogate fuel TRF with two distinct blend ratios. Additionally, it measures the LBV of propanol and its blends with TRF. The research findings reveal that isooctane demonstrates a heightened sensitivity to fuel preheating temperature, whereas the toluene proportion in TRF fuels exerts the most pronounced influence on combustion behavior. At an equivalence ratio of 1.1, the LBV of n-propanol differs from that of its isomer, isopropanol, by 4.65 cm/s. Notably, the LBV exhibits a discernible upward trend, corresponding to the increasing proportion of toluene in the blended fuel. Furthermore, there is a pronounced distinction in LBV among the propanol isomers, with blended TRF occupying an intermediate position between pure propanol and TRF. After the enhancement of the mechanism based on experimental benchmarks of LBV, a rigorous validation process demonstrated a substantial improvement in the alignment between simulated outcomes and empirical LBV measurements.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101846"},"PeriodicalIF":5.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422263","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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