A series of Ni-Mo/ZSM-23 catalysts with a different atomic Mo/(Ni + Mo) ratio was prepared by incipient wetness impregnation with a co-solution of salts of Ni and Mo precursors. The formation of NiMoO4 in the case of oxide catalysts was shown by XRD and Raman spectroscopy. An increase in the molybdenum content in the catalyst composition leads to a decrease in the amount of the NiO phase and an increase in the NiMoO4 phase. This correlates with changes in the activity of the reduced catalysts during the hydrotreating of a mixture of fatty acids (C16-C18) in a flow reactor at 300 °C, PH2 = 2.5 MPa, H2/FAs = 2200 m3/m3 and WHSV = 8.4 h−1. Thus, the highest conversion and iso-alkanes yield were observed in the case of NiMo-0.1 and NiMo-0.25 catalysts. With an increase in the ratio of hydrogen to raw materials to 3150 m3/m3, the highest yield of iso-alkanes is observed on the NiMo-0.4 catalyst.
{"title":"NiMo/ZSM-23 catalysts for deoxygenation and isomerization of C16-C18 fatty acids to sustainable diesel and jet fuel components","authors":"K.S. Kovalevskaya, R.G. Kukushkin, O.O. Zaikina, O.A. Bulavchenko, T.V. Larina, I.S. Golubev, V.A. Yakovlev","doi":"10.1016/j.fuel.2024.133588","DOIUrl":"10.1016/j.fuel.2024.133588","url":null,"abstract":"<div><div>A series of Ni-Mo/ZSM-23 catalysts with a different atomic Mo/(Ni + Mo) ratio was prepared by incipient wetness impregnation with a co-solution of salts of Ni and Mo precursors. The formation of NiMoO<sub>4</sub> in the case of oxide catalysts was shown by XRD and Raman spectroscopy. An increase in the molybdenum content in the catalyst composition leads to a decrease in the amount of the NiO phase and an increase in the NiMoO<sub>4</sub> phase. This correlates with changes in the activity of the reduced catalysts during the hydrotreating of a mixture of fatty acids (C<sub>16</sub>-C<sub>18</sub>) in a flow reactor at 300 °C, P<sub>H2</sub> = 2.5 <!--> <!-->MPa, H<sub>2</sub>/FAs = 2200 <!--> <!-->m<sup>3</sup>/m<sup>3</sup> and WHSV = 8.4 <!--> <!-->h<sup>−1</sup>. Thus, the highest conversion and <em>iso</em>-alkanes yield were observed in the case of NiMo-0.1 and NiMo-0.25 catalysts. With an increase in the ratio of hydrogen to raw materials to 3150 <!--> <!-->m<sup>3</sup>/m<sup>3</sup>, the highest yield of <em>iso</em>-alkanes is observed on the NiMo-0.4 catalyst.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133588"},"PeriodicalIF":6.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-26DOI: 10.1016/j.fuel.2024.133789
Manikandaraja Gurusamy, Balaji Subramanian
This study investigates the effects of hydrogen addition on a compression-ignition (CI) engine that operates on cottonseed oil methyl ester (CSOME). Hydrogen was introduced into the engine inlet manifold at flow rates ranging from 5 Liters per minute (LPM) to 20 LPM, with intervals of 5 LPM (designated as C100H5, C100H10, C100H15, and C100H20). The engine was operated on 100 % Cottonseed Oil Methyl Ester (C100) at various load conditions in a constant speed engine. It was observed that under all load situations, the temperature of the exhaust gas increased as the hydrogen flow rate increased. Maximum of 16.66 % increment in exhaust gas temperature was noted with C100H20 than neat diesel operation. Similarly, as hydrogen induction rates increased, the cut-off ratio, effective compression ratio, and volumetric efficiency all dropped. On the other hand, both brake thermal efficiency and second law efficiency were increased by 16.11 and 13.41 % than neat diesel while operating with C100H20 at 100 % load condition. The peak values for in-cylinder pressure and heat release rate were found to be 4.18 %, and 21.85 % higher than neat diesel for C100H20 with maximum load applied. Nitrogen monoxide emissions increased as a result of the increase in hydrogen induction flow rate by maximum of 40.51 % and then diesel. However, emissions of oxides of carbon (CO and CO2), hydrocarbons, and soot decreased significantly with the introduction of hydrogen. The results indicate that use of hydrogen in CI engine along with cotton seed oil shows positive sign in terms of performance and emission with trends in NO emission which can further be reduced by adopting EGR or After gas treatment.
{"title":"A comprehensive analysis of a dual fuel engine operating on cottonseed oil methyl ester and hydrogen","authors":"Manikandaraja Gurusamy, Balaji Subramanian","doi":"10.1016/j.fuel.2024.133789","DOIUrl":"10.1016/j.fuel.2024.133789","url":null,"abstract":"<div><div>This study investigates the effects of hydrogen addition on a compression-ignition (CI) engine that operates on cottonseed oil methyl ester (CSOME). Hydrogen was introduced into the engine inlet manifold at flow rates ranging from 5 Liters per minute (LPM) to 20 LPM, with intervals of 5 LPM (designated as C100H5, C100H10, C100H15, and C100H20). The engine was operated on 100 % Cottonseed Oil Methyl Ester (C100) at various load conditions in a constant speed engine. It was observed that under all load situations, the temperature of the exhaust gas increased as the hydrogen flow rate increased. Maximum of 16.66 % increment in exhaust gas temperature was noted with C100H20 than neat diesel operation. Similarly, as hydrogen induction rates increased, the cut-off ratio, effective compression ratio, and volumetric efficiency all dropped. On the other hand, both brake thermal efficiency and second law efficiency were increased by 16.11 and 13.41 % than neat diesel while operating with C100H20 at 100 % load condition. The peak values for in-cylinder pressure and heat release rate were found to be 4.18 %, and 21.85 % higher than neat diesel for C100H20 with maximum load applied. Nitrogen monoxide emissions increased as a result of the increase in hydrogen induction flow rate by maximum of 40.51 % and then diesel. However, emissions of oxides of carbon (CO and CO<sub>2</sub>), hydrocarbons, and soot decreased significantly with the introduction of hydrogen. The results indicate that use of hydrogen in CI engine along with cotton seed oil shows positive sign in terms of performance and emission with trends in NO emission which can further be reduced by adopting EGR or After gas treatment.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133789"},"PeriodicalIF":6.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present study, the influences of the carbon quantum dots nanoparticle addition to diesel- microwave-assisted corn oil biodiesel-dimethyl carbonate fuel mixtures on combustion, performance and emissions were experimentally researched in a DI diesel engine at 4.12, 9.61, 15.10 and 20.60 Nm. Lower in-cylinder pressure was measured using fuel mixtures according to diesel. The rise of carbon quantum dot fraction in the fuel mixtures lead to decrease ID. It was also found that SFC declined with the addition of carbon quantum dot nanoparticle in the fuel blends. ITE increased by 6.66 % using CF QD120 ppm according to CF at 15.10 Nm. CD was shortened with fuel mixtures compared to diesel. Test results also showed that clear increase on MPRR and RI has been realized with fuel mixtures. Higher CO was measured using fuel mixtues. Nevertheless, the addition of carbon quantum dot to CF decreased CO emissions. CO declined by about 14.12 % with CF QD120 ppm according to CF at 20.60 Nm. Significant decrease was measured using carbon quantum dot addition on soot emissions whereas NOx emissions increased. Soot emissions reduced by 19 % with CF QD120 ppm compared to CF at 20.6 Nm.
{"title":"Influences of carbon quantum dots nanoparticle addition to diesel- microwave-assisted corn oil biodiesel-dimethyl carbonate fuel blends on combustion, performance and emissions","authors":"Ahmet Uyumaz , Fatih Aksoy , Hamit Solmaz , Alper Calam , Tolga Kocakulak , Yaşar Önder Özgören , Emre Koçer , Laçine Aksoy","doi":"10.1016/j.fuel.2024.133855","DOIUrl":"10.1016/j.fuel.2024.133855","url":null,"abstract":"<div><div>In the present study, the influences of the carbon quantum dots nanoparticle addition to diesel- microwave-assisted corn oil biodiesel-dimethyl carbonate fuel mixtures on combustion, performance and emissions were experimentally researched in a DI diesel engine at 4.12, 9.61, 15.10 and 20.60 Nm. Lower in-cylinder pressure was measured using fuel mixtures according to diesel. The rise of carbon quantum dot fraction in the fuel mixtures lead to decrease ID. It was also found that SFC declined with the addition of carbon quantum dot nanoparticle in the fuel blends. ITE increased by 6.66 % using CF QD120 ppm according to CF at 15.10 Nm. CD was shortened with fuel mixtures compared to diesel. Test results also showed that clear increase on MPRR and RI has been realized with fuel mixtures. Higher CO was measured using fuel mixtues. Nevertheless, the addition of carbon quantum dot to CF decreased CO emissions. CO declined by about 14.12 % with CF QD120 ppm according to CF at 20.60 Nm. Significant decrease was measured using carbon quantum dot addition on soot emissions whereas NO<sub>x</sub> emissions increased. Soot emissions reduced by 19 % with CF QD120 ppm compared to CF at 20.6 Nm.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133855"},"PeriodicalIF":6.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-26DOI: 10.1016/j.fuel.2024.133774
Shuo Yin , Yifang Ren , Jiangping Tian , Zechuan Cui , Xiaolei Zhang , Ping Yan , Keiya Nishida
Ammonia is one of the important fuels that can promote the achievement of carbon neutrality, but its combustion characteristics are not conducive to its application in engines. Injecting hydrogen in the pre-chamber to form a flame jet to ignite the ammonia/air mixture is a method to improve the combustion of ammonia. This ignition method was investigated with the constant volume combustion chamber, high-speed video camera observation and the main-chamber pressure analysis. The flame behavior and combustion characteristics were compared with those ignited by the ammonia flame jet. Hydrogen flame jet significantly enhanced the combustion of the mixture and extended the lean flammability limit. Under conditions of hydrogen injection, the pressure rise delay and combustion duration became shorter, the average heat release rate became higher, and the combustion process was more stable. The hydrogen flame jet rapidly penetrated the main-chamber and impinged on the lower surface, generating intense turbulence. As a result, the combustion pressure took less time to rise from 10% to 50% than it did to go from 50% to 90%. This was different from the situation without hydrogen injection, where time required for both was similar. The hydrogen flame jet was shuttle-shaped when touching the lower surface owing to the rapid combustion speed of hydrogen, while the ammonia flame jet was spindle-shaped with the flame kernel in the center. The combustion process of the flame jet igniting the mixture exhibited two peaks in the heat release rate, reflecting two combustion stages dominated by the flame jet and flame propagation.
{"title":"Combustion characteristics of Ammonia/Air mixture ignited by flame jet with and without hydrogen injection in Pre-Chamber","authors":"Shuo Yin , Yifang Ren , Jiangping Tian , Zechuan Cui , Xiaolei Zhang , Ping Yan , Keiya Nishida","doi":"10.1016/j.fuel.2024.133774","DOIUrl":"10.1016/j.fuel.2024.133774","url":null,"abstract":"<div><div>Ammonia is one of the important fuels that can promote the achievement of carbon neutrality, but its combustion characteristics are not conducive to its application in engines. Injecting hydrogen in the pre-chamber to form a flame jet to ignite the ammonia/air mixture is a method to improve the combustion of ammonia. This ignition method was investigated with the constant volume combustion chamber, high-speed video camera observation and the main-chamber pressure analysis. The flame behavior and combustion characteristics were compared with those ignited by the ammonia flame jet. Hydrogen flame jet significantly enhanced the combustion of the mixture and extended the lean flammability limit. Under conditions of hydrogen injection, the pressure rise delay and combustion duration became shorter, the average heat release rate became higher, and the combustion process was more stable. The hydrogen flame jet rapidly penetrated the main-chamber and impinged on the lower surface, generating intense turbulence. As a result, the combustion pressure took less time to rise from 10% to 50% than it did to go from 50% to 90%. This was different from the situation without hydrogen injection, where time required for both was similar. The hydrogen flame jet was shuttle-shaped when touching the lower surface owing to the rapid combustion speed of hydrogen, while the ammonia flame jet was spindle-shaped with the flame kernel in the center. The combustion process of the flame jet igniting the mixture exhibited two peaks in the heat release rate, reflecting two combustion stages dominated by the flame jet and flame propagation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133774"},"PeriodicalIF":6.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-25DOI: 10.1016/j.fuel.2024.133862
Lanyi Wang , Mengxia You , Xinyu Chen , Shengran Zhou , Dong Li , Di Yu , Chunlei Zhang , Siyu Gao , Xuehua Yu , Bing Liu , Xiaoqiang Fan , Chengyang Yin , Zhen Zhao
n%MnOx/Cu-SSZ-13 catalysts with raspberry-like shapes were synthesized using the steam-assisted method and incipient impregnation methods. The catalytic activities of as-prepared catalysts were also tested for the simultaneous removal of soot and nitrogen oxides (NOx), and the 40 %MnOx/Cu-SSZ-13 catalyst exhibited the best catalytic performance with the lowest Tm temperature (455 °C) for soot combustion, the widest temperature window (144–417 °C) for NO conversion (>90 %), and the highest N2 selectivity (96 %). The obtained catalyst achieves the efficient elimination of NOx and soot in the temperature range of diesel vehicle exhaust emissions because of its rich active oxygen species, sufficient acidic sites, excellent redox properties, high proportion of surface Mn4+, and unique raspberry-like structure. Moreover, the active sites involved in the removal of soot and NOx and reaction mechanism were also elucidated according to the results of density functional theory (DFT) calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs). The results shows that Mn2O3 is the active phase for soot oxidation, while Cu-SSZ-13 is the best choice of active phase for NH3 selective catalytic reduction (NH3-SCR). And the existence of Mn2O3 promotes the reduction of NO on Cu-SSZ-13. Additionally, the 40 %MnOx/Cu-SSZ-13 catalyst followed the E-R mechanism in NH3-SCR at low temperatures as well as NO2-assisted mechanism and the active oxygen mechanism in soot combustion at high temperatures.
{"title":"Raspberry-like shape MnOx/Cu-SSZ-13 catalysts: Facile preparation, catalytic performance and reaction mechanism for the simultaneous removal of soot and NOx","authors":"Lanyi Wang , Mengxia You , Xinyu Chen , Shengran Zhou , Dong Li , Di Yu , Chunlei Zhang , Siyu Gao , Xuehua Yu , Bing Liu , Xiaoqiang Fan , Chengyang Yin , Zhen Zhao","doi":"10.1016/j.fuel.2024.133862","DOIUrl":"10.1016/j.fuel.2024.133862","url":null,"abstract":"<div><div>n%MnOx/Cu-SSZ-13 catalysts with raspberry-like shapes were synthesized using the steam-assisted method and incipient impregnation methods. The catalytic activities of as-prepared catalysts were also tested for the simultaneous removal of soot and nitrogen oxides (NOx), and the 40 %MnOx/Cu-SSZ-13 catalyst exhibited the best catalytic performance with the lowest T<sub>m</sub> temperature (455 °C) for soot combustion, the widest temperature window (144–417 °C) for NO conversion (>90 %), and the highest N<sub>2</sub> selectivity (96 %). The obtained catalyst achieves the efficient elimination of NOx and soot in the temperature range of diesel vehicle exhaust emissions because of its rich active oxygen species, sufficient acidic sites, excellent redox properties, high proportion of surface Mn<sup>4+</sup>, and unique raspberry-like structure. Moreover, the active sites involved in the removal of soot and NOx and reaction mechanism were also elucidated according to the results of density functional theory (DFT) calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs). The results shows that Mn<sub>2</sub>O<sub>3</sub> is the active phase for soot oxidation, while Cu-SSZ-13 is the best choice of active phase for NH<sub>3</sub> selective catalytic reduction (NH<sub>3</sub>-SCR). And the existence of Mn<sub>2</sub>O<sub>3</sub> promotes the reduction of NO on Cu-SSZ-13. Additionally, the 40 %MnOx/Cu-SSZ-13 catalyst followed the E-R mechanism in NH<sub>3</sub>-SCR at low temperatures as well as NO<sub>2</sub>-assisted mechanism and the active oxygen mechanism in soot combustion at high temperatures.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"382 ","pages":"Article 133862"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-25DOI: 10.1016/j.fuel.2024.133655
Eimund Smestad
In this study, kinetic theory was used to derive an equation of state for an exothermic decomposition surface caused by an external gas. The new model is physical, and its quantities have been physically interpreted. A new concept of interaction probability was used to describe the co-volume. This concept describes the interaction between the decomposition surface and the external gas to derive an expression for the linear reaction rate based on kinetic theory. The interaction probability is associated with the particle density of the gases provided by the Lennard-Jones potential and temperature. The Maxwell–Boltzmann distribution was used to establish the initial decomposition conditions based on the concepts of autoignition and activation energy.
The aim of this study was to investigate when burning is a decomposition reaction in which the decomposing molecule contains oxygen and can be used as input to designing fuel cells, rocket motors, and propellants. Therefore, HMX and PETN were used as empirical data, and the new linear reaction rate model provided a good approximation and predicted the burn rate data. The model was compared with Vieille’s law for the normal pressure range. However, the model goes beyond the law and provides good predictions of burn rates with high pressures found in diamond anvil experiments.
{"title":"A theoretical reaction rate model of a chemical exothermic decomposition surface from an external gas","authors":"Eimund Smestad","doi":"10.1016/j.fuel.2024.133655","DOIUrl":"10.1016/j.fuel.2024.133655","url":null,"abstract":"<div><div>In this study, kinetic theory was used to derive an equation of state for an exothermic decomposition surface caused by an external gas. The new model is physical, and its quantities have been physically interpreted. A new concept of interaction probability was used to describe the co-volume. This concept describes the interaction between the decomposition surface and the external gas to derive an expression for the linear reaction rate based on kinetic theory. The interaction probability is associated with the particle density of the gases provided by the Lennard-Jones potential and temperature. The Maxwell–Boltzmann distribution was used to establish the initial decomposition conditions based on the concepts of autoignition and activation energy.</div><div>The aim of this study was to investigate when burning is a decomposition reaction in which the decomposing molecule contains oxygen and can be used as input to designing fuel cells, rocket motors, and propellants. Therefore, HMX and PETN were used as empirical data, and the new linear reaction rate model provided a good approximation and predicted the burn rate data. The model was compared with Vieille’s law <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mi>b</mi></mrow></msub><mo>=</mo><mi>a</mi><mspace></mspace><msup><mrow><mi>P</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></math></span> for the normal pressure range. However, the model goes beyond the law and provides good predictions of burn rates with high pressures found in diamond anvil experiments.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133655"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-25DOI: 10.1016/j.fuel.2024.133618
Rongkun Pan , Hedi Shen , Pengyu Wang , Hailin Jia , Jiangkun Chao
In this study, to address the problems of the weak inhibition effect and short action time of a single inhibitor on coal oxidation, a novel composite inhibitor of Luteolin/Tea polyphenol/Urea (LTU) was proposed. The inhibition effects and mechanisms of LTU and other traditional inhibitors (NaHCO3 and VC) on coal sample oxidation were compared and analyzed using a C600 high-precision calorimeter, a temperature-programmed oxidation device and Fourier transform infrared spectroscopy. The experimental results showed that LTU had an obvious synergistic effect on the inhibition of coal spontaneous combustion (CSC): 1) LTU could increase the initial exothermic temperature point, prolong the endothermic stage, and reduce the exothermic intensity of coal-oxygen reaction; 2) The coal sample treated with LTU showed a significant decrease in the concentration of carbon oxygen and alkane gases released, and an increase in the gas production temperature point, which was better than the inhibition effect of NaHCO3 and VC under the same conditions. 3) The physical components of LTU could encapsulate the coal, insulate the oxygen, absorb heat and decrease the temperature; moreover, its chemical components could consume (–OH), (RO-), (ROO-) in the chain reaction, inert the free radicals in the chain reaction, inhibit oxidization and block CSC. This study provides an efficient and economical chemical inhibitor for safe production in the coal industry and important theoretical support for a deeper understanding of the CSC inhibition mechanism.
{"title":"Study on the inhibition of coal oxidation characteristics and thermal effect of Luteolin/Tea polyphenols/Urea","authors":"Rongkun Pan , Hedi Shen , Pengyu Wang , Hailin Jia , Jiangkun Chao","doi":"10.1016/j.fuel.2024.133618","DOIUrl":"10.1016/j.fuel.2024.133618","url":null,"abstract":"<div><div>In this study, to address the problems of the weak inhibition effect and short action time of a single inhibitor on coal oxidation, a novel composite inhibitor of Luteolin/Tea polyphenol/Urea (LTU) was proposed. The inhibition effects and mechanisms of LTU and other traditional inhibitors (NaHCO<sub>3</sub> and VC) on coal sample oxidation were compared and analyzed using a C600 high-precision calorimeter, a temperature-programmed oxidation device and Fourier transform infrared spectroscopy. The experimental results showed that LTU had an obvious synergistic effect on the inhibition of coal spontaneous combustion (CSC): 1) LTU could increase the initial exothermic temperature point, prolong the endothermic stage, and reduce the exothermic intensity of coal-oxygen reaction; 2) The coal sample treated with LTU showed a significant decrease in the concentration of carbon oxygen and alkane gases released, and an increase in the gas production temperature point, which was better than the inhibition effect of NaHCO<sub>3</sub> and VC under the same conditions. 3) The physical components of LTU could encapsulate the coal, insulate the oxygen, absorb heat and decrease the temperature; moreover, its chemical components could consume (–OH), (RO-), (ROO-) in the chain reaction, inert the free radicals in the chain reaction, inhibit oxidization and block CSC. This study provides an efficient and economical chemical inhibitor for safe production in the coal industry and important theoretical support for a deeper understanding of the CSC inhibition mechanism.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"382 ","pages":"Article 133618"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report hydrogen production from waste through waste gasification and the water–gas shift reaction using highly stable Co/CeO2 catalysts. Here, careful control of the KOH:K2CO3 precipitant ratio during CeO2 support synthesis yielded highly active and stable Co/CeO2 catalysts. Crucially, the precipitant ratio affects the Co dispersion, oxygen vacancies, crystallinity, and Co-CeO2 interactions, and the Co dispersion increases with increase in KOH content. Further, the oxygen storage capacity improves at the optimal KOH:K2CO3 ratio. In addition, the Co-CeO2 interaction is enhanced when catalysts are synthesized using CeO2 with a large amount of K2CO3. All prepared Co/CeO2 catalysts show high CO conversion, even at extremely high gas hourly space velocities: the Co/CeO2 (λ = 2:1 and 1:1.5) catalysts exhibit stable performance because of robust Co-CeO2 interactions, high oxygen storage capacities, and effective Co dispersions. These findings aid hydrogen production from waste and CeO2 support design for various catalytic reactions.
{"title":"Highly stable Co/CeO2 catalyst for high-temperature water–gas shift reaction using a CeO2 support with an optimized precipitant ratio","authors":"Beom-Su Cheon , Hak-Min Kim , Jae-Hoon Hwang , Dae-Woon Jeong","doi":"10.1016/j.fuel.2024.133777","DOIUrl":"10.1016/j.fuel.2024.133777","url":null,"abstract":"<div><div>We report hydrogen production from waste through waste gasification and the water–gas shift reaction using highly stable Co/CeO<sub>2</sub> catalysts. Here, careful control of the KOH:K<sub>2</sub>CO<sub>3</sub> precipitant ratio during CeO<sub>2</sub> support synthesis yielded highly active and stable Co/CeO<sub>2</sub> catalysts. Crucially, the precipitant ratio affects the Co dispersion, oxygen vacancies, crystallinity, and Co-CeO<sub>2</sub> interactions, and the Co dispersion increases with increase in KOH content. Further, the oxygen storage capacity improves at the optimal KOH:K<sub>2</sub>CO<sub>3</sub> ratio. In addition, the Co-CeO<sub>2</sub> interaction is enhanced when catalysts are synthesized using CeO<sub>2</sub> with a large amount of K<sub>2</sub>CO<sub>3</sub>. All prepared Co/CeO<sub>2</sub> catalysts show high CO conversion, even at extremely high gas hourly space velocities: the Co/CeO<sub>2</sub> (λ = 2:1 and 1:1.5) catalysts exhibit stable performance because of robust Co-CeO<sub>2</sub> interactions, high oxygen storage capacities, and effective Co dispersions. These findings aid hydrogen production from waste and CeO<sub>2</sub> support design for various catalytic reactions.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"383 ","pages":"Article 133777"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-25DOI: 10.1016/j.fuel.2024.133820
Yinglong Zhang, Zhennan He, Pei Zhao, Gongming Xin, Ning Qin
A significant amount of natural gas is stored in a form of hydrate. Yet commercial exploitation of natural gas hydrate remains quite challenging due to limited comprehension of internal heat and mass transfer processes. In this work, a numerical model is developed to describe heat and mass transfer during methane hydrate decomposition and to provide sufficient data for neural network modeling. Based on the numerical model, the temporal and spatial evolution patterns of several decomposition characteristics, including multiphase saturation, temperature, gas pressure, and gas velocity, are elucidated. More importantly, the effects of 19 types of variables related to various boundary conditions, physical properties, and initial conditions are comprehensively investigated. A comprehensive correlation map between these variables and four key heat and mass transfer parameters reveals 41 positive and 35 negative correlations. Driven by abundant simulation data, an artificial neural network model is then developed to predict the heat and mass transfer parameters. As validated, the neural network model shows satisfactory efficiency and accuracy, achieving relative errors below 2% in the prediction of various heat and mass transfer parameters. This study provides a comprehensive theoretical guide and a useful method for understanding, regulating, and optimizing the natural gas hydrate exploitation.
{"title":"Comprehensive correlation analysis enabled neural network prediction of heat and mass transfer during gas hydrate decomposition","authors":"Yinglong Zhang, Zhennan He, Pei Zhao, Gongming Xin, Ning Qin","doi":"10.1016/j.fuel.2024.133820","DOIUrl":"10.1016/j.fuel.2024.133820","url":null,"abstract":"<div><div>A significant amount of natural gas is stored in a form of hydrate. Yet commercial exploitation of natural gas hydrate remains quite challenging due to limited comprehension of internal heat and mass transfer processes. In this work, a numerical model is developed to describe heat and mass transfer during methane hydrate decomposition and to provide sufficient data for neural network modeling. Based on the numerical model, the temporal and spatial evolution patterns of several decomposition characteristics, including multiphase saturation, temperature, gas pressure, and gas velocity, are elucidated. More importantly, the effects of 19 types of variables related to various boundary conditions, physical properties, and initial conditions are comprehensively investigated. A comprehensive correlation map between these variables and four key heat and mass transfer parameters reveals 41 positive and 35 negative correlations. Driven by abundant simulation data, an artificial neural network model is then developed to predict the heat and mass transfer parameters. As validated, the neural network model shows satisfactory efficiency and accuracy, achieving relative errors below 2% in the prediction of various heat and mass transfer parameters. This study provides a comprehensive theoretical guide and a useful method for understanding, regulating, and optimizing the natural gas hydrate exploitation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"382 ","pages":"Article 133820"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-25DOI: 10.1016/j.fuel.2024.133646
Xiao-Dong Zhou , Xue-Long Yin , Lang Liu , Xue-Li Huang , Jing-Mei Liu , Ting Liu , He Lin , Feng-Yun Ma
Understanding hydrogen activation is crucial for improving the performance of direct coal liquefaction (DCL) which is essential for the clean, efficient conversion of coal to fuel oils and aromatic chemicals. Three hydrogen sources are involved in DCL: solvent hydrogen (SH), dissolved hydrogen that reacts directly (DHD), and dissolved hydrogen that reacts through a solvent (DHS). Quantitatively studying DHS is challenging because it is generated through the dehydrogenation of hydrogen-donor solvents produced via the hydrogenation of gas-phase H2 and solvents. This research establishes for the first time a quantitative method for determining DHS consumption (DHSC) based on protium- and deuterium-nuclear-magnetic-resonance results for solvents after isotope-tracer reactions. Comparative experiments and quantum-chemical calculations were performed to confirm the method’s reliability. The isotope-tracer method showed that DHSC accounts for < 7 % of the total hydrogen consumption under catalysis with ferric stearate, nickel stearate, or molybdenum 2-ethylhexanoate, while DHD consumption accounts for > 50 %. Thus, DHD, rather than DHS, is the primary hydrogen source for catalytic activation. Furthermore, the comparative experiments also showed that hydrogen consumption is greater for one hydrogen source than for the coexistence of the three hydrogen sources, indicating competition among the three sources. The quantum-chemical calculations showed that the competitiveness among the three sources follows the order of DHS < SH < DHD, this agrees with the order of hydrogen consumption in the isotope-tracer experiments. This study quantitatively reveals the mechanism responsible for hydrogen activation by catalysts and provides a scientific basis for optimization and mutual matching of solvents and catalysts.
{"title":"Using isotope-tracer method with deuterium for quantitative study of hydrogen activation mechanism in direct coal liquefaction","authors":"Xiao-Dong Zhou , Xue-Long Yin , Lang Liu , Xue-Li Huang , Jing-Mei Liu , Ting Liu , He Lin , Feng-Yun Ma","doi":"10.1016/j.fuel.2024.133646","DOIUrl":"10.1016/j.fuel.2024.133646","url":null,"abstract":"<div><div>Understanding hydrogen activation is crucial for improving the performance of direct coal liquefaction (DCL) which is essential for the clean, efficient conversion of coal to fuel oils and aromatic chemicals. Three hydrogen sources are involved in DCL: solvent hydrogen (SH), dissolved hydrogen that reacts directly (DHD), and dissolved hydrogen that reacts through a solvent (DHS). Quantitatively studying DHS is challenging because it is generated through the dehydrogenation of hydrogen-donor solvents produced via the hydrogenation of gas-phase H<sub>2</sub> and solvents. This research establishes for the first time a quantitative method for determining DHS consumption (DHSC) based on protium- and deuterium-nuclear-magnetic-resonance results for solvents after isotope-tracer reactions. Comparative experiments and quantum-chemical calculations were performed to confirm the method’s reliability. The isotope-tracer method showed that DHSC accounts for < 7 % of the total hydrogen consumption under catalysis with ferric stearate, nickel stearate, or molybdenum 2-ethylhexanoate, while DHD consumption accounts for > 50 %. Thus, DHD, rather than DHS, is the primary hydrogen source for catalytic activation. Furthermore, the comparative experiments also showed that hydrogen consumption is greater for one hydrogen source than for the coexistence of the three hydrogen sources, indicating competition among the three sources. The quantum-chemical calculations showed that the competitiveness among the three sources follows the order of DHS < SH < DHD, this agrees with the order of hydrogen consumption in the isotope-tracer experiments. This study quantitatively reveals the mechanism responsible for hydrogen activation by catalysts and provides a scientific basis for optimization and mutual matching of solvents and catalysts.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"382 ","pages":"Article 133646"},"PeriodicalIF":6.7,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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