Pub Date : 2025-08-18DOI: 10.1016/j.fuproc.2025.108303
D. König, J. Ströhle, B. Epple
In this paper, the influence of oxy-fuel operation with flue gas recirculation on the occurrence of minority species in a semi-industrial combustion chamber is analyzed. The change of classical air combustion to an oxidizer mixture of O2 and flue gas in oxy-fuel combustion shows different changes in the formation of minority species like and SO2. This is due to the present of high levels of CO2 and a back feeding of this gaseous pollutant components into the combustion chamber through flue gas recirculation. In total, the changing formation mechanisms due to the presence of higher CO2 concentrations in the combustion chamber, leading to increased amounts of nitrogen, sulfur and chlorine based species. During oxy-fuel combustion, the formation of CS2 in the center of the flame is significantly higher, due to the availability of CO2. When comparing different oxygen concentrations in oxy-fuel flames, it is evident that the lowest oxygen concentration most closely resembles the air combustion case. This suggests that the overall formation of nitrogen, sulfur, and chlorine species and the burnout of those in the flame is highly dependent on the flame temperature. Therefore, a reduction in flame temperature leads to a corresponding decrease in the formation of these species in both air and oxy-fuel combustion scenarios.
{"title":"Investigation on the formation of nitrogen, sulfur and chlorine species in air and oxy-fuel combustion of biomass in a semi-industrial combustion chamber","authors":"D. König, J. Ströhle, B. Epple","doi":"10.1016/j.fuproc.2025.108303","DOIUrl":"10.1016/j.fuproc.2025.108303","url":null,"abstract":"<div><div>In this paper, the influence of oxy-fuel operation with flue gas recirculation on the occurrence of minority species in a semi-industrial combustion chamber is analyzed. The change of classical air combustion to an oxidizer mixture of O<sub>2</sub> and flue gas in oxy-fuel combustion shows different changes in the formation of minority species like <figure><img></figure> and SO<sub>2</sub>. This is due to the present of high levels of CO<sub>2</sub> and a back feeding of this gaseous pollutant components into the combustion chamber through flue gas recirculation. In total, the changing formation mechanisms due to the presence of higher CO<sub>2</sub> concentrations in the combustion chamber, leading to increased amounts of nitrogen, sulfur and chlorine based species. During oxy-fuel combustion, the formation of CS<sub>2</sub> in the center of the flame is significantly higher, due to the availability of CO<sub>2</sub>. When comparing different oxygen concentrations in oxy-fuel flames, it is evident that the lowest oxygen concentration most closely resembles the air combustion case. This suggests that the overall formation of nitrogen, sulfur, and chlorine species and the burnout of those in the flame is highly dependent on the flame temperature. Therefore, a reduction in flame temperature leads to a corresponding decrease in the formation of these species in both air and oxy-fuel combustion scenarios.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108303"},"PeriodicalIF":7.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860887","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 : 2025-08-18DOI: 10.1016/j.fuproc.2025.108307
M. Yavuz , I.T. Yilmaz
The present study aims to analyse the combustion-related parameters in a reactivity-controlled compression ignition (RCCI) engine with a dual-fuel approach for diesel and biogas fuels. The objective is to investigate how varying biogas energy share ratios (50 %, 60 %, 70 %, and 80 %) affect combustion behaviour at different engine loads (40, 60, and 80 Nm). All tests were conducted at a constant engine speed of 1750 rpm. Results from dual-fuel operation were compared to baseline diesel combustion. The findings indicated that an increase in the biogas addition generally resulted in the deterioration of combustion stability, as evidenced by elevated ignition delays and COVIMEP values. However, this negative impact was mitigated at higher engine loads and increased diesel pilot ratios. As the quantity of biogas increased, a rise in cylinder pressures, pressure rise rates, ignition delays and ringing intensities was observed. Conversely, combustion stabilities, peak heat release rates and combustion durations all decreased. This research contributes to advancing sustainable practices in engine technology by promoting alternative fuel adoption in internal combustion engines, aligning with efforts to enhance energy efficiency and sustainability in the transportation sector.
{"title":"Influence of pilot diesel ratio and engine load on combustion behaviour in a biogas-fueled RCCI engine","authors":"M. Yavuz , I.T. Yilmaz","doi":"10.1016/j.fuproc.2025.108307","DOIUrl":"10.1016/j.fuproc.2025.108307","url":null,"abstract":"<div><div>The present study aims to analyse the combustion-related parameters in a reactivity-controlled compression ignition (RCCI) engine with a dual-fuel approach for diesel and biogas fuels. The objective is to investigate how varying biogas energy share ratios (50 %, 60 %, 70 %, and 80 %) affect combustion behaviour at different engine loads (40, 60, and 80 Nm). All tests were conducted at a constant engine speed of 1750 rpm. Results from dual-fuel operation were compared to baseline diesel combustion. The findings indicated that an increase in the biogas addition generally resulted in the deterioration of combustion stability, as evidenced by elevated ignition delays and COV<sub>IMEP</sub> values. However, this negative impact was mitigated at higher engine loads and increased diesel pilot ratios. As the quantity of biogas increased, a rise in cylinder pressures, pressure rise rates, ignition delays and ringing intensities was observed. Conversely, combustion stabilities, peak heat release rates and combustion durations all decreased. This research contributes to advancing sustainable practices in engine technology by promoting alternative fuel adoption in internal combustion engines, aligning with efforts to enhance energy efficiency and sustainability in the transportation sector.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108307"},"PeriodicalIF":7.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860888","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 : 2025-08-14DOI: 10.1016/j.fuproc.2025.108310
Akram Ali Nasser Mansoor Al-Haimi , Fatma Yehia , Fen Liu , Xiang Zhen , Shunni Zhu , Zhongming Wang
This study explores, for the first time, the catalytic application of two previously developed methanesulfonic acid-based deep eutectic solvents (MSA-based DESs), namely MSA/choline chloride (MSA/ChCl) and MSA/tetraoctylammonium bromide (MSA/TOAB), for the transesterification of triglyceride-based oils into biodiesel. The aim was to develop recyclable acid catalysts and integrated processing strategies for biodiesel production, leveraging the thermal stability and recovery potential of MSA-based DESs. While these DESs have exhibited efficiency in esterification, their performance in transesterification remains unexamined. Both DESs were assessed under atmospheric and pressurized conditions to evaluate catalytic activity, methanol retention, and process efficiency. Fatty acid methyl ester (FAME) yields were quantified by gas chromatography, revealing that under mild conditions, the methanol retention system enabled slow but sustained conversion, with MSA/ChCl reaching 45.34 % yield after 30 d. Transitioning to a pressurized reactor significantly enhanced reaction kinetics, with MSA/ChCl reaching a FAME yield of 97 % within 3 h under optimized conditions (120 °C, 2 wt% catalyst, 60 wt% methanol). Further increases in DES concentration enabled yields exceeding 99 %. Key parameters, including methanol dosage, reaction time, temperature, and DES concentration, were optimized, and catalyst reusability was validated over five cycles, with yields remaining above 83 %. A closed-loop process was proposed for DES and methanol recovery to enhance scalability and minimize waste. This work extends the application of MSA-based DESs to transesterification, demonstrating a recyclable, high-activity Brønsted acid catalyst capable of achieving high biodiesel yields at low dosage, thereby addressing key limitations of conventional acid systems and supporting the development of sustainable industrial biodiesel processes.
{"title":"Recyclable methanesulfonic acid-based deep eutectic solvents for efficient biodiesel production via transesterification","authors":"Akram Ali Nasser Mansoor Al-Haimi , Fatma Yehia , Fen Liu , Xiang Zhen , Shunni Zhu , Zhongming Wang","doi":"10.1016/j.fuproc.2025.108310","DOIUrl":"10.1016/j.fuproc.2025.108310","url":null,"abstract":"<div><div>This study explores, for the first time, the catalytic application of two previously developed methanesulfonic acid-based deep eutectic solvents (MSA-based DESs), namely MSA/choline chloride (MSA/ChCl) and MSA/tetraoctylammonium bromide (MSA/TOAB), for the transesterification of triglyceride-based oils into biodiesel. The aim was to develop recyclable acid catalysts and integrated processing strategies for biodiesel production, leveraging the thermal stability and recovery potential of MSA-based DESs. While these DESs have exhibited efficiency in esterification, their performance in transesterification remains unexamined. Both DESs were assessed under atmospheric and pressurized conditions to evaluate catalytic activity, methanol retention, and process efficiency. Fatty acid methyl ester (FAME) yields were quantified by gas chromatography, revealing that under mild conditions, the methanol retention system enabled slow but sustained conversion, with MSA/ChCl reaching 45.34 % yield after 30 d. Transitioning to a pressurized reactor significantly enhanced reaction kinetics, with MSA/ChCl reaching a FAME yield of 97 % within 3 h under optimized conditions (120 °C, 2 wt% catalyst, 60 wt% methanol). Further increases in DES concentration enabled yields exceeding 99 %. Key parameters, including methanol dosage, reaction time, temperature, and DES concentration, were optimized, and catalyst reusability was validated over five cycles, with yields remaining above 83 %. A closed-loop process was proposed for DES and methanol recovery to enhance scalability and minimize waste. This work extends the application of MSA-based DESs to transesterification, demonstrating a recyclable, high-activity Brønsted acid catalyst capable of achieving high biodiesel yields at low dosage, thereby addressing key limitations of conventional acid systems and supporting the development of sustainable industrial biodiesel processes.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108310"},"PeriodicalIF":7.7,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831030","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 : 2025-08-14DOI: 10.1016/j.fuproc.2025.108308
Julian Türck , Sebastian Riess , Lukas Strauß , Fabian Schmitt , Ralf Türck , Wolfgang Ruck , Michael Wensing , Jürgen Krahl
The defossilization of diesel fuels presents a multitude of new opportunities and challenges. Due to the increase in complexity and interactions between the components, it is necessary to examine the drop-in capability of new fuel components. One aspect of this is the influence on spray formation of the fuel. This work addresses the spray behavior of isopropylideneglycerine (solketal) and its influence on a multicomponent diesel blend (Diesel R33: 33 % renewable share). In general, it represents the first spray study of solketal. It enables value to be added from glycerin and, according to initial combustion tests, has a promising emissions profile due to its higher molecular oxygen density. The mass flow rate, penetration depth and cone angle were examined by using high-temperature and -pressure injection chamber equipped by optical diagnostics (Mie scattering setup and schlieren imaging system). These parameters are examined under varying fuel temperatures, injection pressures and ambient conditions. Solketal as a pure compound exhibits the expected behavior i.e. it is drop-in compatible even with varying parameters. The influence of solketal on Diesel R33 reveals that, in comparison to solketal-free blends, larger maximum mass flows are generated. It also shows that the penetration depths decrease (up to 34 %). In addition, there is more fuel in the gas phase, which may be a result of the comparatively low boiling point. In general, the influence of solketal suggests that fuel-induced soot reduction could be possible in existing fleets.
{"title":"Investigation of the spray formation of solketal under diesel engine conditions and the influence on Diesel R33.","authors":"Julian Türck , Sebastian Riess , Lukas Strauß , Fabian Schmitt , Ralf Türck , Wolfgang Ruck , Michael Wensing , Jürgen Krahl","doi":"10.1016/j.fuproc.2025.108308","DOIUrl":"10.1016/j.fuproc.2025.108308","url":null,"abstract":"<div><div>The defossilization of diesel fuels presents a multitude of new opportunities and challenges. Due to the increase in complexity and interactions between the components, it is necessary to examine the drop-in capability of new fuel components. One aspect of this is the influence on spray formation of the fuel. This work addresses the spray behavior of isopropylideneglycerine (solketal) and its influence on a multicomponent diesel blend (Diesel R33: 33 % renewable share). In general, it represents the first spray study of solketal. It enables value to be added from glycerin and, according to initial combustion tests, has a promising emissions profile due to its higher molecular oxygen density. The mass flow rate, penetration depth and cone angle were examined by using high-temperature and -pressure injection chamber equipped by optical diagnostics (Mie scattering setup and schlieren imaging system). These parameters are examined under varying fuel temperatures, injection pressures and ambient conditions. Solketal as a pure compound exhibits the expected behavior i.e. it is drop-in compatible even with varying parameters. The influence of solketal on Diesel R33 reveals that, in comparison to solketal-free blends, larger maximum mass flows are generated. It also shows that the penetration depths decrease (up to 34 %). In addition, there is more fuel in the gas phase, which may be a result of the comparatively low boiling point. In general, the influence of solketal suggests that fuel-induced soot reduction could be possible in existing fleets.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108308"},"PeriodicalIF":7.7,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841555","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 : 2025-08-03DOI: 10.1016/j.fuproc.2025.108301
Shikai Xing , Yunge Zhao , Jianbing Gao , Junfeng Huang , Xiaochen Wang , Sunchu Wu , Xianglong Li
As a zero‑carbon fuel, ammonia is characterized by a high ignition temperature and slow laminar flame speed. Ammonia/diesel dual-fuel (ADDF) mode effectively improves ammonia combustion characteristics. This study employs a three-dimensional computational fluid dynamics model to systematically investigate the effects of diesel injection strategies on the combustion and emission characteristics of ADDF engine at low ammonia energy ratios (ammonia energy ratios below 30 %). The findings reveal that the pre-injection strategy markedly enhances the combustion efficiency and reduces emissions compared to the single-injection strategy. When the start of diesel pre-injection (SODI-pre) and the diesel split ratio (DSR) are −47.2 °CA and 20 %, the indicated thermal efficiency of the engine reaches 47.04 %, with an improvement of 1.47 % over the single-injection strategy. Meanwhile, greenhouse gas emissions are reduced by 16.92 %. The combustion of the diesel pre-injection generates a high-temperature environment at the SODI-pre of −17.2 °CA. This promotes the evaporation and combustion of the main-injected diesel, thereby increasing the peak in-cylinder pressure. However, regarding the cases of the SODI-pre of −27.2 °CA and − 37.2 °CA, the combustion phase advances significantly. The extended interval between the onset of combustion and the main-injection suppresses the combustion of the main-injected diesel, leading to a reduction in peak in-cylinder pressure. The in-cylinder combustion is improved when the SODI-pre is advanced to −47.2 °CA. In the combustion process, a notable increase in combustion zones at the center of the combustion chamber is observed. Meanwhile, a significant reduction in low-temperature combustion regions contributes to a substantial decrease of N2O emissions. Additionally, the increase of DSR enhances the in-cylinder mixture uniformity, allowing more of the combustible mixture to burn, resulting in an increase of peak in-cylinder pressure.
{"title":"Investigation of diesel pre-injection effects on combustion and emission characteristics in a small-displacement ammonia/diesel dual-fuel engine","authors":"Shikai Xing , Yunge Zhao , Jianbing Gao , Junfeng Huang , Xiaochen Wang , Sunchu Wu , Xianglong Li","doi":"10.1016/j.fuproc.2025.108301","DOIUrl":"10.1016/j.fuproc.2025.108301","url":null,"abstract":"<div><div>As a zero‑carbon fuel, ammonia is characterized by a high ignition temperature and slow laminar flame speed. Ammonia/diesel dual-fuel (ADDF) mode effectively improves ammonia combustion characteristics. This study employs a three-dimensional computational fluid dynamics model to systematically investigate the effects of diesel injection strategies on the combustion and emission characteristics of ADDF engine at low ammonia energy ratios (ammonia energy ratios below 30 %). The findings reveal that the pre-injection strategy markedly enhances the combustion efficiency and reduces emissions compared to the single-injection strategy. When the start of diesel pre-injection (SODI-pre) and the diesel split ratio (DSR) are −47.2 °CA and 20 %, the indicated thermal efficiency of the engine reaches 47.04 %, with an improvement of 1.47 % over the single-injection strategy. Meanwhile, greenhouse gas emissions are reduced by 16.92 %. The combustion of the diesel pre-injection generates a high-temperature environment at the SODI-pre of −17.2 °CA. This promotes the evaporation and combustion of the main-injected diesel, thereby increasing the peak in-cylinder pressure. However, regarding the cases of the SODI-pre of −27.2 °CA and − 37.2 °CA, the combustion phase advances significantly. The extended interval between the onset of combustion and the main-injection suppresses the combustion of the main-injected diesel, leading to a reduction in peak in-cylinder pressure. The in-cylinder combustion is improved when the SODI-pre is advanced to −47.2 °CA. In the combustion process, a notable increase in combustion zones at the center of the combustion chamber is observed. Meanwhile, a significant reduction in low-temperature combustion regions contributes to a substantial decrease of N<sub>2</sub>O emissions. Additionally, the increase of DSR enhances the in-cylinder mixture uniformity, allowing more of the combustible mixture to burn, resulting in an increase of peak in-cylinder pressure.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108301"},"PeriodicalIF":7.7,"publicationDate":"2025-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767006","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 : 2025-07-31DOI: 10.1016/j.fuproc.2025.108297
Sepideh Izaddoust , Idoia Hita , Timo Kekäläinen , José Valecillos , Janne Jänis , Pedro Castaño , Eva Epelde
The transformation of 1-butene into valuable fuels using HZSM-5 zeolite catalysts is significantly hindered by deactivation caused by deposited species and coke formation. This work delves into the entrapment, formation, and growth of these species during 1-butene oligomerization at 275–325 °C, 1.5–40 bar, and space-times of 2–6 gcat h molC−1. We have employed an extensive characterization of the used catalysts, integrating conventional techniques with high-resolution mass spectrometry (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, FT-ICR MS). This advanced technique provides a detailed molecular-level analysis of these species. Our findings reveal that higher pressures promote oligomerization, resulting in an increased accumulation of trapped oligomer species. Conversely, higher temperatures facilitate the cracking of these oligomers into lighter fractions or their further conversion into coke molecules through condensation reactions. This dual behavior underscores the complex interplay between temperature and pressure in influencing the deactivation pathways. By understanding the overall reaction mechanism and the formation and growth patterns of trapped and deactivating species, we can develop strategies to mitigate catalyst deactivation, ultimately leading to more efficient industrial applications.
利用HZSM-5沸石催化剂将1-丁烯转化为有价值的燃料，由于沉积物和焦炭的形成而导致失活。这项工作深入研究了在275-325°C， 1.5-40 bar和2-6 gcat h molC−1的空间时间下，这些物种在1-丁烯寡聚过程中的捕获，形成和生长。我们对所用催化剂进行了广泛的表征，将传统技术与高分辨率质谱法（傅里叶变换离子回旋共振质谱法，FT-ICR MS）相结合。这项先进的技术为这些物种提供了详细的分子水平分析。我们的研究结果表明，较高的压力促进了低聚，导致被困低聚物种类的积累增加。相反，较高的温度有利于这些低聚物裂解成较轻的馏分或通过缩合反应进一步转化为焦炭分子。这种双重行为强调了影响失活途径的温度和压力之间的复杂相互作用。通过了解整个反应机制以及捕获和失活物种的形成和生长模式，我们可以制定减轻催化剂失活的策略，最终实现更有效的工业应用。
{"title":"Profiling the trapped and deactivating species on HZSM-5 zeolite during 1-butene oligomerization","authors":"Sepideh Izaddoust , Idoia Hita , Timo Kekäläinen , José Valecillos , Janne Jänis , Pedro Castaño , Eva Epelde","doi":"10.1016/j.fuproc.2025.108297","DOIUrl":"10.1016/j.fuproc.2025.108297","url":null,"abstract":"<div><div>The transformation of 1-butene into valuable fuels using HZSM-5 zeolite catalysts is significantly hindered by deactivation caused by deposited species and coke formation. This work delves into the entrapment, formation, and growth of these species during 1-butene oligomerization at 275–325 °C, 1.5–40 bar, and space-times of 2–6 g<sub>cat</sub> h mol<sub>C</sub><sup>−1</sup>. We have employed an extensive characterization of the used catalysts, integrating conventional techniques with high-resolution mass spectrometry (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, FT-ICR MS). This advanced technique provides a detailed molecular-level analysis of these species. Our findings reveal that higher pressures promote oligomerization, resulting in an increased accumulation of trapped oligomer species. Conversely, higher temperatures facilitate the cracking of these oligomers into lighter fractions or their further conversion into coke molecules through condensation reactions. This dual behavior underscores the complex interplay between temperature and pressure in influencing the deactivation pathways. By understanding the overall reaction mechanism and the formation and growth patterns of trapped and deactivating species, we can develop strategies to mitigate catalyst deactivation, ultimately leading to more efficient industrial applications.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108297"},"PeriodicalIF":7.7,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739102","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 : 2025-07-31DOI: 10.1016/j.fuproc.2025.108300
Liu Huixin , Wang Chunbo , Sun Cen , Yu Xuewu , Zhang Xiaotian
Ammonia co-firing with biomass is a vital strategy for decarbonizing power generation, yet optimizing its efficiency and emissions necessitates accurate flame temperature monitoring. Reliable diagnosis, however, is impeded by strong, phase-dependent non-gray radiation from biomass (volatile vs. char) and the critically unquantified impact of NH3 on essential spectral radiative properties. This work systematically investigates the influence of NH3 concentration on the spectral emissivity ε(λ) of burning rice husk particles within the visible spectrum (400–700 nm) during distinct volatile and char combustion phases, utilizing simultaneous spectroscopy and RGB pyrometry. The investigation revealed that NH3 significantly lowers ε(λ) for both volatile combustion, where ελ decreases with wavelength (ε(λ) < 0.16), and char combustion, where ελ increases with wavelength (ε(λ) ≈ 0.35–0.75). Consequently, the key emissivity ratio εg/εr (at 530/600 nm) required for RGB pyrometry exhibited opposite behaviors: for volatile combustion, εg/εr > 1 and increased with NH3 concentration, whereas for char combustion, εg/εr < 1 and decreased with NH3 concentration. Building upon these quantitative findings, the developed and validated spectrally-guided RGB pyrometry methodology successfully corrects the substantial temperature overestimation inherent in the gray-body assumption, an error particularly pronounced at higher NH3 concentrations. This work yields both fundamental quantitative data on ammonia's impact on biomass non-gray radiation and a robust spectrally-guided diagnostic method, providing essential data and techniques for enabling accurate modeling, optimization, and control of biomass-ammonia co-firing processes.
{"title":"Elucidating ammonia's impact on non-gray radiation and thermometry during biomass co-firing via spectral guidance","authors":"Liu Huixin , Wang Chunbo , Sun Cen , Yu Xuewu , Zhang Xiaotian","doi":"10.1016/j.fuproc.2025.108300","DOIUrl":"10.1016/j.fuproc.2025.108300","url":null,"abstract":"<div><div>Ammonia co-firing with biomass is a vital strategy for decarbonizing power generation, yet optimizing its efficiency and emissions necessitates accurate flame temperature monitoring. Reliable diagnosis, however, is impeded by strong, phase-dependent non-gray radiation from biomass (volatile vs. char) and the critically unquantified impact of NH<sub>3</sub> on essential spectral radiative properties. This work systematically investigates the influence of NH<sub>3</sub> concentration on the spectral emissivity <em>ε(λ)</em> of burning rice husk particles within the visible spectrum (400–700 nm) during distinct volatile and char combustion phases, utilizing simultaneous spectroscopy and RGB pyrometry. The investigation revealed that NH<sub>3</sub> significantly lowers <em>ε(λ)</em> for both volatile combustion, where <em>ε</em><sub><em>λ</em></sub> decreases with wavelength (<em>ε(λ)</em> < 0.16), and char combustion, where <em>ε</em><sub><em>λ</em></sub> increases with wavelength (<em>ε(λ)</em> ≈ 0.35–0.75). Consequently, the key emissivity ratio <em>ε</em><sub><em>g</em></sub><em>/ε</em><sub><em>r</em></sub> (at 530/600 nm) required for RGB pyrometry exhibited opposite behaviors: for volatile combustion, <em>ε</em><sub><em>g</em></sub><em>/ε</em><sub><em>r</em></sub> > 1 and increased with NH<sub>3</sub> concentration, whereas for char combustion, <em>ε</em><sub><em>g</em></sub><em>/ε</em><sub><em>r</em></sub> < 1 and decreased with NH<sub>3</sub> concentration. Building upon these quantitative findings, the developed and validated spectrally-guided RGB pyrometry methodology successfully corrects the substantial temperature overestimation inherent in the gray-body assumption, an error particularly pronounced at higher NH<sub>3</sub> concentrations. This work yields both fundamental quantitative data on ammonia's impact on biomass non-gray radiation and a robust spectrally-guided diagnostic method, providing essential data and techniques for enabling accurate modeling, optimization, and control of biomass-ammonia co-firing processes.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108300"},"PeriodicalIF":7.7,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739101","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 : 2025-07-30DOI: 10.1016/j.fuproc.2025.108298
Zhiyuan Zhang , Yanyan Xu , Guixia Fan , Yingrui Jin , Daoguang Teng , Guosheng Li , Peng Li , Yijun Cao
Germanium, a critical metal used in many strategy fields, is widely acknowledged as organic affinity. Germanium is main occurred in the humus of lignite, but its exact occurrence state remains unclear. In this work, various methods were employed to leach germanium from lignite to reveal the germanium occurrence state. Germanium tends to accumulate in specific germanium-endowed structures, but most germanium is bound to and encapsulated in enwrapping structures such as humic acid. It could be extracted either by co-extraction with humic acid (e.g. ammonoxidation, alkaline leaching) or by dissociating the germanium-endowed structure (e.g. thionyl chloride leaching, acid demineralization, and hydrochloric acid leaching). In germanium-rich lignite, germanium was directly connected to oxygen and chelated by the phenolic hydroxyl in the ortho- in the form of a five-membered ring. Furthermore, germanium existed in the germanium-endowed structure in the form of a six-coordinated, deformed octahedron, externally encapsulated by interfering substances. Therefore, this study provides a theoretical basis for targeted extraction of germanium from germanium-rich lignite.
{"title":"Leaching behavior of germanium from germanium-rich lignite: A further comprehension of its occurrence state","authors":"Zhiyuan Zhang , Yanyan Xu , Guixia Fan , Yingrui Jin , Daoguang Teng , Guosheng Li , Peng Li , Yijun Cao","doi":"10.1016/j.fuproc.2025.108298","DOIUrl":"10.1016/j.fuproc.2025.108298","url":null,"abstract":"<div><div>Germanium, a critical metal used in many strategy fields, is widely acknowledged as organic affinity. Germanium is main occurred in the humus of lignite, but its exact occurrence state remains unclear. In this work, various methods were employed to leach germanium from lignite to reveal the germanium occurrence state. Germanium tends to accumulate in specific germanium-endowed structures, but most germanium is bound to and encapsulated in enwrapping structures such as humic acid. It could be extracted either by co-extraction with humic acid (<em>e.g.</em> ammonoxidation, alkaline leaching) or by dissociating the germanium-endowed structure (<em>e.g.</em> thionyl chloride leaching, acid demineralization, and hydrochloric acid leaching). In germanium-rich lignite, germanium was directly connected to oxygen and chelated by the phenolic hydroxyl in the ortho- in the form of a five-membered ring. Furthermore, germanium existed in the germanium-endowed structure in the form of a six-coordinated, deformed octahedron, externally encapsulated by interfering substances. Therefore, this study provides a theoretical basis for targeted extraction of germanium from germanium-rich lignite.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108298"},"PeriodicalIF":7.7,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739103","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 : 2025-07-29DOI: 10.1016/j.fuproc.2025.108292
Shanzhi Liu , Jiabao Lv , Zhikai Lang , Xingqi Li , Jianhua Yan , Xiaodong Li , Yaqi Peng , Yunchao Li , Dingkun Yuan , Jian Wu , Angjian Wu
Renewable-driven non-thermal plasma (NTP) technology provides a potentially sustainable alternative for ammonia (NH3) production. Nonetheless, energy efficiency remains a critical bottleneck in NTP reactors. Herein, we propose a multi-hollow dielectric barrier discharge (MDBD) plasma reactor to realize nitrogen hydrogenation towards ambient NH3 synthesis, with the physicochemical characteristics systematically explored for the first time. Transient discharge dynamics were captured by electrical characterization, meanwhile the active intermediate species and the low-temperature properties of MDBD were unveiled by optical spectrum diagnosis. Effects of feed gas, flow rate and specific energy input (SEI) on reaction activity were investigated in terms of energy efficiency (EE) and energy consumption (EC). Notably, remarkable reaction efficacy was realized under low driving powers. For a fully-developed 'steady' discharge, an EE of 1.32 g/kWh and an EC of 46.44 MJ/mol could be attained at 3.20 W. Under a pulse-like fluctuating 'flicker' mode at merely 1.15 W, the EE and EC were improved to 1.78 g/kWh and 34.35 MJ/mol, respectively, further highlighting the energy-effectiveness of MDBD. This work provides a novel approach for energy-efficient, environmental-friendly and distributed NH3 production.
{"title":"Multi-hollow dielectric barrier discharge plasma: An energy-efficient strategy towards mild ammonia synthesis","authors":"Shanzhi Liu , Jiabao Lv , Zhikai Lang , Xingqi Li , Jianhua Yan , Xiaodong Li , Yaqi Peng , Yunchao Li , Dingkun Yuan , Jian Wu , Angjian Wu","doi":"10.1016/j.fuproc.2025.108292","DOIUrl":"10.1016/j.fuproc.2025.108292","url":null,"abstract":"<div><div>Renewable-driven non-thermal plasma (NTP) technology provides a potentially sustainable alternative for ammonia (NH<sub>3</sub>) production. Nonetheless, energy efficiency remains a critical bottleneck in NTP reactors. Herein, we propose a multi-hollow dielectric barrier discharge (MDBD) plasma reactor to realize nitrogen hydrogenation towards ambient NH<sub>3</sub> synthesis, with the physicochemical characteristics systematically explored for the first time. Transient discharge dynamics were captured by electrical characterization, meanwhile the active intermediate species and the low-temperature properties of MDBD were unveiled by optical spectrum diagnosis. Effects of feed gas, flow rate and specific energy input (SEI) on reaction activity were investigated in terms of energy efficiency (EE) and energy consumption (EC). Notably, remarkable reaction efficacy was realized under low driving powers. For a fully-developed 'steady' discharge, an EE of 1.32 g/kWh and an EC of 46.44 MJ/mol could be attained at 3.20 W. Under a pulse-like fluctuating 'flicker' mode at merely 1.15 W, the EE and EC were improved to 1.78 g/kWh and 34.35 MJ/mol, respectively, further highlighting the energy-effectiveness of MDBD. This work provides a novel approach for energy-efficient, environmental-friendly and distributed NH<sub>3</sub> production.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"277 ","pages":"Article 108292"},"PeriodicalIF":7.7,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722792","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 : 2025-07-28DOI: 10.1016/j.fuproc.2025.108290
Yi Zhang , Jacques Monnier , Philip Bulsink , Moataz Abdrabou , Jian Li , Xin Pang , Nafiseh Zaker , Rafal Gieleciak
Diesel production from lignocellulosic biomass-derived fast pyrolysis bio-oil (FPBO) and catalytic pyrolysis bio-oil (CPBO) was investigated with an upgrading approach using unsupported MoS2 catalysts generated in situ. Hydrodeoxygenation of FPBO and CPBO was evaluated in a continuous-flow reactor system using feed blends containing 18 wt% bio-oil in fuel oil. For FPBO, 92.9 % deoxygenation was achieved with 0.51 wt% O in oil products, resulting in low acidity (0.32 mg KOH/g), while 74.8 % deoxygenation was obtained for CPBO with 1.24 wt% O and 0.48 mg KOH/g acidity in oil products. The lower deoxygenation of CPBO suggests that oxygenates in CPBO are less reactive than those in FPBO. In both cases, low solid yields were observed from 1.2 to 2.0 g/100 g bio-oil. XRD and HRTEM detected few-layer stacked structure for the in-situ formed MoS2 catalysts. The oil product from CPBO retained more biogenic carbon than from FPBO, with the diesel fraction from CPBO exhibiting a higher biogenic carbon content and yield. Both diesel cuts meet almost all ASTM D975 specifications, except for S content, resulting from the high S/Mo feed ratio used in the tests. Evaluation results demonstrated great potential for producing specifications-conforming diesel fractions from FPBO and CPBO upgrading using unsupported MoS2 catalyst.
{"title":"Evaluation of diesel fuel production from bio-oils hydrodeoxygenation using unsupported MoS2 catalysts","authors":"Yi Zhang , Jacques Monnier , Philip Bulsink , Moataz Abdrabou , Jian Li , Xin Pang , Nafiseh Zaker , Rafal Gieleciak","doi":"10.1016/j.fuproc.2025.108290","DOIUrl":"10.1016/j.fuproc.2025.108290","url":null,"abstract":"<div><div>Diesel production from lignocellulosic biomass-derived fast pyrolysis bio-oil (FPBO) and catalytic pyrolysis bio-oil (CPBO) was investigated with an upgrading approach using unsupported MoS<sub>2</sub> catalysts generated in situ. Hydrodeoxygenation of FPBO and CPBO was evaluated in a continuous-flow reactor system using feed blends containing 18 wt% bio-oil in fuel oil. For FPBO, 92.9 % deoxygenation was achieved with 0.51 wt% O in oil products, resulting in low acidity (0.32 mg KOH/g), while 74.8 % deoxygenation was obtained for CPBO with 1.24 wt% O and 0.48 mg KOH/g acidity in oil products. The lower deoxygenation of CPBO suggests that oxygenates in CPBO are less reactive than those in FPBO. In both cases, low solid yields were observed from 1.2 to 2.0 g/100 g bio-oil. XRD and HRTEM detected few-layer stacked structure for the in-situ formed MoS<sub>2</sub> catalysts. The oil product from CPBO retained more biogenic carbon than from FPBO, with the diesel fraction from CPBO exhibiting a higher biogenic carbon content and yield. Both diesel cuts meet almost all ASTM D975 specifications, except for S content, resulting from the high S/Mo feed ratio used in the tests. Evaluation results demonstrated great potential for producing specifications-conforming diesel fractions from FPBO and CPBO upgrading using unsupported MoS<sub>2</sub> catalyst.</div></div>","PeriodicalId":326,"journal":{"name":"Fuel Processing Technology","volume":"276 ","pages":"Article 108290"},"PeriodicalIF":7.2,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713174","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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