U. M. A. Devaraja, Chamini Lakshika Wickramarathna Dissanayake, D. Gunarathne, Wei-hsin Chen
Torrefaction is a vital pretreatment technology for thermochemical biorefinery applications like pyrolysis, gasification, and liquefaction. Oxidative torrefaction, an economical version of torrefaction, has recently gained much attention in the renewable energy field. Recent literature on inert and oxidative torrefaction was critically reviewed in this work to provide necessary guidance for future research and commercial implementations. The critical performance parameters of torrefaction for thermochemical biorefinery applications, such as solid yield, energy yield, carbon enhancement, higher heating value (HHV) enhancement, and energy-mass co-benefit index (EMCI), were also analyzed. Agricultural waste, woody biomass, and microalgae were considered. The analysis reveals that woody biomass could equally benefit from oxidative or inert torrefaction. In contrast, inert torrefaction was found more suitable for agricultural wastes and microalgae. Using flue gas as the oxidative torrefaction medium and waste biomass as the feedstock could achieve a circular economy, improving the sustainability of oxidative torrefaction for thermochemical biorefineries. The significant challenges in oxidative torrefaction include high ash content in torrefied agricultural waste, the oxidative thermal runaway of fibrous biomass during torrefaction, temperature control, and scale-up in reactors. Some proposed solutions to address these challenges are combined washing and torrefaction pretreatment, balancing oxygen content, temperature, and residence time, depending on the biomass type, and recirculating torrefaction gases.
{"title":"Oxidative torrefaction and torrefaction-based biorefining of biomass: a critical review","authors":"U. M. A. Devaraja, Chamini Lakshika Wickramarathna Dissanayake, D. Gunarathne, Wei-hsin Chen","doi":"10.18331/brj2022.9.3.4","DOIUrl":"https://doi.org/10.18331/brj2022.9.3.4","url":null,"abstract":"Torrefaction is a vital pretreatment technology for thermochemical biorefinery applications like pyrolysis, gasification, and liquefaction. Oxidative torrefaction, an economical version of torrefaction, has recently gained much attention in the renewable energy field. Recent literature on inert and oxidative torrefaction was critically reviewed in this work to provide necessary guidance for future research and commercial implementations. The critical performance parameters of torrefaction for thermochemical biorefinery applications, such as solid yield, energy yield, carbon enhancement, higher heating value (HHV) enhancement, and energy-mass co-benefit index (EMCI), were also analyzed. Agricultural waste, woody biomass, and microalgae were considered. The analysis reveals that woody biomass could equally benefit from oxidative or inert torrefaction. In contrast, inert torrefaction was found more suitable for agricultural wastes and microalgae. Using flue gas as the oxidative torrefaction medium and waste biomass as the feedstock could achieve a circular economy, improving the sustainability of oxidative torrefaction for thermochemical biorefineries. The significant challenges in oxidative torrefaction include high ash content in torrefied agricultural waste, the oxidative thermal runaway of fibrous biomass during torrefaction, temperature control, and scale-up in reactors. Some proposed solutions to address these challenges are combined washing and torrefaction pretreatment, balancing oxygen content, temperature, and residence time, depending on the biomass type, and recirculating torrefaction gases.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46020382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biofuel systems may represent a promising strategy to combat climate change by replacing fossil fuels in electricity generation and transportation. First-generation biofuels from sugar and starch crops for ethanol (a gasoline substitute) and from oilseed crops for biodiesel (a petroleum diesel substitute) have come under increasing levels of scrutiny due to the uncertainty associated with the estimation of climate change impacts of biofuels, such as due to indirect effects on land use. This analysis estimates the magnitude of some uncertainty sources: i) crop/feedstock, ii) life cycle assessment (LCA) modelling approach, iii) land-use change (LUC), and iv) greenhouse gas (GHG) metrics. The metrics used for characterising the different GHGs (global warming potential-GWP and global temperature change potential-GTP at different time horizons) appeared not to play a significant role in explaining the variance in the carbon footprint of biofuels, as opposed to the crop/feedstock used, the inclusion/exclusion of LUC considerations, and the LCA modelling approach (p<0.001). The estimated climate footprint of biofuels is dependent on the latter three parameters and, thus, is context-specific. It is recommended that these parameters be dealt with in a manner consistent with the goal and scope of the study. In particular, it is essential to interpret the results of the carbon footprint of biofuel systems in light of the choices made in each of these sources of uncertainty, and sensitivity analysis is recommended to overcome their influence on the result.
{"title":"On quantifying sources of uncertainty in the carbon footprint of biofuels: crop/feedstock, LCA modelling approach, land-use change, and GHG metrics","authors":"M. Brandão, R. Heijungs, A. Cowie","doi":"10.18331/brj2022.9.2.2","DOIUrl":"https://doi.org/10.18331/brj2022.9.2.2","url":null,"abstract":"Biofuel systems may represent a promising strategy to combat climate change by replacing fossil fuels in electricity generation and transportation. First-generation biofuels from sugar and starch crops for ethanol (a gasoline substitute) and from oilseed crops for biodiesel (a petroleum diesel substitute) have come under increasing levels of scrutiny due to the uncertainty associated with the estimation of climate change impacts of biofuels, such as due to indirect effects on land use. This analysis estimates the magnitude of some uncertainty sources: i) crop/feedstock, ii) life cycle assessment (LCA) modelling approach, iii) land-use change (LUC), and iv) greenhouse gas (GHG) metrics. The metrics used for characterising the different GHGs (global warming potential-GWP and global temperature change potential-GTP at different time horizons) appeared not to play a significant role in explaining the variance in the carbon footprint of biofuels, as opposed to the crop/feedstock used, the inclusion/exclusion of LUC considerations, and the LCA modelling approach (p<0.001). The estimated climate footprint of biofuels is dependent on the latter three parameters and, thus, is context-specific. It is recommended that these parameters be dealt with in a manner consistent with the goal and scope of the study. In particular, it is essential to interpret the results of the carbon footprint of biofuel systems in light of the choices made in each of these sources of uncertainty, and sensitivity analysis is recommended to overcome their influence on the result.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48809986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biodiesel is viewed as the alternative to petroleum diesel, but its poor low-temperature performance constrains its utilization. Cloud point (CP), the onset temperature of thermal crystallization, appropriately shows the low-temperature performance. The effective way to reduce CP is to remove saturated fatty acid methyl esters (FAMEs). Compared to current methods, this work describes an extraordinary approach to fractionating FAMEs by forming solid urea inclusion compounds (UICs). Urea inclusion fractionation reduces the CPs by removing high melting-point linear saturated FAME components. Urea inclusion fractionation in this study was performed under various processing conditions: mass ratios of urea to FAMEs and solvents to FAMEs, various solvents, FAMEs from various feedstocks, and processing temperatures. Supersaturation of urea in the solution is the driving force, and it significantly affects yield, composition, CP, separation efficiency, and selectivity. Through a single urea inclusion fractionation process, FAMEs, except palm oil FAMEs, resulted in CP reduction ranging from 20 to 42 oC with a yield of 77–80% depending on the compositions. CP of palm oil FAMEs could reach as low as -17 oC with a yield of 46% after twice urea inclusion fractionation. According to the model prediction, the cetane number after urea inclusion fractionation decreased about 0.7–2 but was still higher than the minimum biodiesel requirement. Oxidation stability after urea inclusion decreased according to the proposed model, but this can be mitigated by adding antioxidants. Emission evaluation after urea inclusion fractionation indicated decreased hydrocarbons, carbon monoxide, and particulate matter. However, it resulted in the increasing emission of nitrogen oxides.
{"title":"Fractionation of fatty acid methyl esters via urea inclusion and its application to improve the low-temperature performance of biodiesel","authors":"Junli Liu, B. Tao","doi":"10.18331/brj2022.9.2.3","DOIUrl":"https://doi.org/10.18331/brj2022.9.2.3","url":null,"abstract":"Biodiesel is viewed as the alternative to petroleum diesel, but its poor low-temperature performance constrains its utilization. Cloud point (CP), the onset temperature of thermal crystallization, appropriately shows the low-temperature performance. The effective way to reduce CP is to remove saturated fatty acid methyl esters (FAMEs). Compared to current methods, this work describes an extraordinary approach to fractionating FAMEs by forming solid urea inclusion compounds (UICs). Urea inclusion fractionation reduces the CPs by removing high melting-point linear saturated FAME components. Urea inclusion fractionation in this study was performed under various processing conditions: mass ratios of urea to FAMEs and solvents to FAMEs, various solvents, FAMEs from various feedstocks, and processing temperatures. Supersaturation of urea in the solution is the driving force, and it significantly affects yield, composition, CP, separation efficiency, and selectivity. Through a single urea inclusion fractionation process, FAMEs, except palm oil FAMEs, resulted in CP reduction ranging from 20 to 42 oC with a yield of 77–80% depending on the compositions. CP of palm oil FAMEs could reach as low as -17 oC with a yield of 46% after twice urea inclusion fractionation. According to the model prediction, the cetane number after urea inclusion fractionation decreased about 0.7–2 but was still higher than the minimum biodiesel requirement. Oxidation stability after urea inclusion decreased according to the proposed model, but this can be mitigated by adding antioxidants. Emission evaluation after urea inclusion fractionation indicated decreased hydrocarbons, carbon monoxide, and particulate matter. However, it resulted in the increasing emission of nitrogen oxides.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45729749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Gea, I. Irvan, K. Wijaya, A. Nadia, A. Pulungan, J. Sihombing, Rahayu Rahayu
Bio-oil includes significant levels of oxygenate molecules, which might induce component instability and reduce its physicochemical qualities. To counteract this, the component must undergo a hydrodeoxygenation (HDO) reaction. Due to the presence of acidic active sites, zeolites have been shown to have high hydrogenation and deoxygenation capabilities. However, natural zeolite has a large number of impurities and low acidity density. Consequently, before being employed as an HDO catalyst, pretreatments such as preparation and activation are required. In this study, the catalyst used was an active natural zeolite whose acidity level varied depending on the Si/Al ratio after dealumination with 3, 5, and 7 M hydrochloric acid, proceeded by calcination with nitrogen gas flow (designated as Z3, Z5, and Z7, respectively). The results showed that dealumination and calcination of zeolite generally caused changes in its physical characteristics and components. The Z5 catalyst showed the best catalytic performance in the HDO process of bio-oil. The higher heating value (HHV) of bio-oil increased from 12 to 18 MJ/kg, the viscosity value doubled, the degree of deoxygenation increased to 77%, and the water content reduced dramatically to about one-third of that of raw bio-oil. Moreover, control compounds, such as carboxylic acids, decreased slightly, but the amount of phenol increased to about twice the content in raw bio-oil.
{"title":"Bio-oil hydrodeoxygenation over acid activated-zeolite with different Si/Al ratio","authors":"S. Gea, I. Irvan, K. Wijaya, A. Nadia, A. Pulungan, J. Sihombing, Rahayu Rahayu","doi":"10.18331/brj2022.9.2.4","DOIUrl":"https://doi.org/10.18331/brj2022.9.2.4","url":null,"abstract":"Bio-oil includes significant levels of oxygenate molecules, which might induce component instability and reduce its physicochemical qualities. To counteract this, the component must undergo a hydrodeoxygenation (HDO) reaction. Due to the presence of acidic active sites, zeolites have been shown to have high hydrogenation and deoxygenation capabilities. However, natural zeolite has a large number of impurities and low acidity density. Consequently, before being employed as an HDO catalyst, pretreatments such as preparation and activation are required. In this study, the catalyst used was an active natural zeolite whose acidity level varied depending on the Si/Al ratio after dealumination with 3, 5, and 7 M hydrochloric acid, proceeded by calcination with nitrogen gas flow (designated as Z3, Z5, and Z7, respectively). The results showed that dealumination and calcination of zeolite generally caused changes in its physical characteristics and components. The Z5 catalyst showed the best catalytic performance in the HDO process of bio-oil. The higher heating value (HHV) of bio-oil increased from 12 to 18 MJ/kg, the viscosity value doubled, the degree of deoxygenation increased to 77%, and the water content reduced dramatically to about one-third of that of raw bio-oil. Moreover, control compounds, such as carboxylic acids, decreased slightly, but the amount of phenol increased to about twice the content in raw bio-oil.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48237638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zahra Shams Esfandabadi, Meisam Ranjbari, S. Scagnelli
The Ukraine war has immensely affected both food and energy systems due to the significant role of Russia in supplying natural gas and fertilizers globally and the extensive contribution of both Russia and Ukraine in exporting grains and oilseeds to the international markets. Hence, the Ukraine-Russia conflict has resulted in a shortage of crops and grains in the food market, especially in Europe, causing speculations if these resources should still be used for biofuel production (1st Generation). However, the International Energy Agency has warned that lowering biofuel mandates could result in rising petroleum demand and supply concerns. In light of these unfolding events, a systems thinking approach is required to monitor and analyze the implications of this crisis for food and biofuel markets as a whole to alleviate the concerns faced and plan sustainably. In this vein, based on the trade-offs between food system elements and the biofuel supply chain, as well as the potential effects of the war on the food and energy systems worldwide, a causal loop diagram is developed in the present work. According to the insights provided, the key to preventing food insecurity and keeping biofuel mandates on an increasing trend simultaneously amid the Ukraine war is to switch from the 1st Generation biofuels to higher generations. This transition would reduce not only the pressure on the food market to move toward zero hunger (SDG 2) but also pave the way to move towards a circular economy and clean and affordable energy (SDG 7) during the post-war era.
{"title":"The imbalance of food and biofuel markets amid Ukraine-Russia crisis: A systems thinking perspective","authors":"Zahra Shams Esfandabadi, Meisam Ranjbari, S. Scagnelli","doi":"10.18331/brj2022.9.2.5","DOIUrl":"https://doi.org/10.18331/brj2022.9.2.5","url":null,"abstract":"The Ukraine war has immensely affected both food and energy systems due to the significant role of Russia in supplying natural gas and fertilizers globally and the extensive contribution of both Russia and Ukraine in exporting grains and oilseeds to the international markets. Hence, the Ukraine-Russia conflict has resulted in a shortage of crops and grains in the food market, especially in Europe, causing speculations if these resources should still be used for biofuel production (1st Generation). However, the International Energy Agency has warned that lowering biofuel mandates could result in rising petroleum demand and supply concerns. In light of these unfolding events, a systems thinking approach is required to monitor and analyze the implications of this crisis for food and biofuel markets as a whole to alleviate the concerns faced and plan sustainably. In this vein, based on the trade-offs between food system elements and the biofuel supply chain, as well as the potential effects of the war on the food and energy systems worldwide, a causal loop diagram is developed in the present work. According to the insights provided, the key to preventing food insecurity and keeping biofuel mandates on an increasing trend simultaneously amid the Ukraine war is to switch from the 1st Generation biofuels to higher generations. This transition would reduce not only the pressure on the food market to move toward zero hunger (SDG 2) but also pave the way to move towards a circular economy and clean and affordable energy (SDG 7) during the post-war era.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47302261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Shahbeig, Alireza Shafizadeh, M. Rosen, B. Sels
Biomass gasification technology is a promising process to produce a stable gas with a wide range of applications, from direct use to the synthesis of value-added biochemicals and biofuels. Due to the high capital/operating costs of the technology and the necessity for prudent management of thermal energy exchanges in the biomass gasification process, it is important to use advanced sustainability metrics to ensure that environmental and other sustainability factors are addressed beneficially. Consequently, various engineering techniques are being used to make decisions on endogenous and exogenous parameters of biomass gasification processes to find the most efficient, viable, and sustainable operations and conditions. Among available approaches, exergy methods have attracted much attention due to their scientific rigor in accounting for the performance, cost, and environmental impact of biomass gasification systems. Therefore, this review is devoted to critically reviewing and numerically scrutinizing the use of exergy methods in analyzing biomass gasification systems. First, a bibliometric analysis is conducted to systematically identify research themes and trends in exergy-based sustainability assessments of biomass gasification systems. Then, the effects of biomass composition, reactor type, gasifying agent, and operating parameters on the exergy efficiency of the process are thoroughly investigated and mechanistically discussed. Unlike oxygen, nitrogen, and ash contents of biomass, the exergy efficiency of the gasification process is positively correlated with the carbon and hydrogen contents of biomass. A mixed gasifying medium (CO2 and steam) provides higher exergy efficiency values. The downdraft fixed-bed gasifier exhibits the highest exergy efficiency among biomass gasification systems. Finally, opportunities and limitations of exergy methods for analyzing sustainability aspects of biomass gasification systems are outlined to guide future research in this domain.
{"title":"Exergy sustainability analysis of biomass gasification: a critical review","authors":"H. Shahbeig, Alireza Shafizadeh, M. Rosen, B. Sels","doi":"10.18331/brj2022.9.1.5","DOIUrl":"https://doi.org/10.18331/brj2022.9.1.5","url":null,"abstract":"Biomass gasification technology is a promising process to produce a stable gas with a wide range of applications, from direct use to the synthesis of value-added biochemicals and biofuels. Due to the high capital/operating costs of the technology and the necessity for prudent management of thermal energy exchanges in the biomass gasification process, it is important to use advanced sustainability metrics to ensure that environmental and other sustainability factors are addressed beneficially. Consequently, various engineering techniques are being used to make decisions on endogenous and exogenous parameters of biomass gasification processes to find the most efficient, viable, and sustainable operations and conditions. Among available approaches, exergy methods have attracted much attention due to their scientific rigor in accounting for the performance, cost, and environmental impact of biomass gasification systems. Therefore, this review is devoted to critically reviewing and numerically scrutinizing the use of exergy methods in analyzing biomass gasification systems. First, a bibliometric analysis is conducted to systematically identify research themes and trends in exergy-based sustainability assessments of biomass gasification systems. Then, the effects of biomass composition, reactor type, gasifying agent, and operating parameters on the exergy efficiency of the process are thoroughly investigated and mechanistically discussed. Unlike oxygen, nitrogen, and ash contents of biomass, the exergy efficiency of the gasification process is positively correlated with the carbon and hydrogen contents of biomass. A mixed gasifying medium (CO2 and steam) provides higher exergy efficiency values. The downdraft fixed-bed gasifier exhibits the highest exergy efficiency among biomass gasification systems. Finally, opportunities and limitations of exergy methods for analyzing sustainability aspects of biomass gasification systems are outlined to guide future research in this domain.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47903029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hande Ermis, Ünzile Güven-Gülhan, Tunahan Çakır, M. Altınbaş
Economizing microalgal cultivation is a considerable milestone targeted by efforts put into microalgal biorefineries. In light of that, the present study was aimed to explore the potential of using anaerobic liquid digestate (ALD) as culture media to grow microalgae and compared it with three different synthetic media (i.e., N8, BBM, and M8) in terms of biomass yield, fatty acid composition, and nutrient utilization/recovery. Moreover, a mixed culture of wild-type microalgae was employed in this study owing to the ability of mixed cultures to survive extreme conditions, eliminating the risk of losing the culture easily, as it mostly happens with pure cultures. The highest nutrient yield coefficients were achieved when the mixed microalgae culture was cultivated in ALD, where the yield coefficient for nitrogen (YN) and yield coefficient for phosphorus (YP) were 10.7 mg biomass mg-1 N and 98 mg biomass mg-1 P, respectively. The highest lipid content (34%) and the highest concentrations of C16:0 (114 mg L-1) and C18:0 (60.9 mg L-1) were also recorded when the mixed microalgae culture was cultivated in ALD. Furthermore, the polyunsaturated fatty acids (PUFA) content also increased significantly in ALD, a beneficial phenomenon as PUFAs in microalgae allow them to adapt more effectively to extreme conditions. Based on the microbial community analysis performed using the multi-marker metabarcoding approach, Diphylleia rotans, Synechocystis PCC-6803, Cyanobium gracile PCC 6307, and Chlorella sorokiniana were identified as the most abundant species in the ALD growth. Overall, based on the findings of the present study, ALD could be used as a promising cultivation medium for microalgae, offering a process integration approach to combine anaerobic digestion and algae cultivation as an effective way to simultaneously treat the high-strength dark-colored ALD and valorize it into profitable byproducts.
{"title":"Microalgae growth and diversity in anaerobic digestate compared to synthetic media","authors":"Hande Ermis, Ünzile Güven-Gülhan, Tunahan Çakır, M. Altınbaş","doi":"10.18331/brj2022.9.1.2","DOIUrl":"https://doi.org/10.18331/brj2022.9.1.2","url":null,"abstract":"Economizing microalgal cultivation is a considerable milestone targeted by efforts put into microalgal biorefineries. In light of that, the present study was aimed to explore the potential of using anaerobic liquid digestate (ALD) as culture media to grow microalgae and compared it with three different synthetic media (i.e., N8, BBM, and M8) in terms of biomass yield, fatty acid composition, and nutrient utilization/recovery. Moreover, a mixed culture of wild-type microalgae was employed in this study owing to the ability of mixed cultures to survive extreme conditions, eliminating the risk of losing the culture easily, as it mostly happens with pure cultures. The highest nutrient yield coefficients were achieved when the mixed microalgae culture was cultivated in ALD, where the yield coefficient for nitrogen (YN) and yield coefficient for phosphorus (YP) were 10.7 mg biomass mg-1 N and 98 mg biomass mg-1 P, respectively. The highest lipid content (34%) and the highest concentrations of C16:0 (114 mg L-1) and C18:0 (60.9 mg L-1) were also recorded when the mixed microalgae culture was cultivated in ALD. Furthermore, the polyunsaturated fatty acids (PUFA) content also increased significantly in ALD, a beneficial phenomenon as PUFAs in microalgae allow them to adapt more effectively to extreme conditions. Based on the microbial community analysis performed using the multi-marker metabarcoding approach, Diphylleia rotans, Synechocystis PCC-6803, Cyanobium gracile PCC 6307, and Chlorella sorokiniana were identified as the most abundant species in the ALD growth. Overall, based on the findings of the present study, ALD could be used as a promising cultivation medium for microalgae, offering a process integration approach to combine anaerobic digestion and algae cultivation as an effective way to simultaneously treat the high-strength dark-colored ALD and valorize it into profitable byproducts.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46041425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Rosyadi, S. Suyitno, Albert Xaverio Ilyas, Afif Faishal, Andres Budiono, Mirza Yusuf
Co-gasification contributes significantly to the generation of hydrogen-rich syngas since it not only addresses the issue of feedstock variation but also has synergistic benefits. In this article, recent research on hydrogen concentration and yield, tar content, gasification efficiency, and carbon conversion efficiency is explored systematically. In feedstocks with high water content, steam gasification and supercritical hydrothermal gasification technologies are ideal for producing hydrogen at a concentration of 57%, which can be increased to 82.9% using purification technology. Carbonized coals, chars, and cokes have high microwave absorption when used as feedstocks. Moreover, coconut activated carbon contains elements that provide a high tan δ value and are worthy of further development as feedstocks, adsorbents or catalysts. Meanwhile, the FeSO4 catalyst has the greatest capacity for storing microwave energy and producing dielectric losses; therefore, it can serve as both a catalyst and microwave absorber. Although microwave heating is preferable to conventional heating, the amount of hydrogen it generates remains modest, at 60% and 32.75% in single-feeding and co-feeding modes, respectively. The heating value of syngas produced using microwaves is 17.44 MJ/m³, much more than that produced via conventional heating. Thus, despite a lack of research on hydrogen-rich syngas generation based on co-gasification and microwave heating, such techniques have the potential to be developed at both laboratory and industrial scales. In addition, the dielectric characteristics of feedstocks, beds, adsorbents, and catalysts must be further investigated to optimize the performance of microwave heating processes.
{"title":"Producing hydrogen-rich syngas via microwave heating and co-gasification: a systematic review","authors":"I. Rosyadi, S. Suyitno, Albert Xaverio Ilyas, Afif Faishal, Andres Budiono, Mirza Yusuf","doi":"10.18331/brj2022.9.1.4","DOIUrl":"https://doi.org/10.18331/brj2022.9.1.4","url":null,"abstract":"Co-gasification contributes significantly to the generation of hydrogen-rich syngas since it not only addresses the issue of feedstock variation but also has synergistic benefits. In this article, recent research on hydrogen concentration and yield, tar content, gasification efficiency, and carbon conversion efficiency is explored systematically. In feedstocks with high water content, steam gasification and supercritical hydrothermal gasification technologies are ideal for producing hydrogen at a concentration of 57%, which can be increased to 82.9% using purification technology. Carbonized coals, chars, and cokes have high microwave absorption when used as feedstocks. Moreover, coconut activated carbon contains elements that provide a high tan δ value and are worthy of further development as feedstocks, adsorbents or catalysts. Meanwhile, the FeSO4 catalyst has the greatest capacity for storing microwave energy and producing dielectric losses; therefore, it can serve as both a catalyst and microwave absorber. Although microwave heating is preferable to conventional heating, the amount of hydrogen it generates remains modest, at 60% and 32.75% in single-feeding and co-feeding modes, respectively. The heating value of syngas produced using microwaves is 17.44 MJ/m³, much more than that produced via conventional heating. Thus, despite a lack of research on hydrogen-rich syngas generation based on co-gasification and microwave heating, such techniques have the potential to be developed at both laboratory and industrial scales. In addition, the dielectric characteristics of feedstocks, beds, adsorbents, and catalysts must be further investigated to optimize the performance of microwave heating processes.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46410040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Patrícia Carvalho, Carlos E. Costa, Sara L. Baptista, L. Domingues
Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review.
{"title":"Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy","authors":"Patrícia Carvalho, Carlos E. Costa, Sara L. Baptista, L. Domingues","doi":"10.18331/brj2021.8.4.4","DOIUrl":"https://doi.org/10.18331/brj2021.8.4.4","url":null,"abstract":"Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41923536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ethanol can be used as an alternative fuel for spark-ignition (SI) engines to increase the octane number and oxygen content of ethanol/gasoline blends, thereby reducing dependence on fossil fuels and the exhaust emissions of incomplete combustion products. Although it is widely agreed that ethanol can reduce CO and HC exhaust emissions, the literature on ethanol and NOX emissions is far from conclusive; hence there is a need for an in-depth, updated review of ethanol/gasoline blends in SI engines and the relative production of NOX emissions. In light of that, the present work aims to provide a comprehensive literature review on the current state of ethanol combustion in SI engines to shed definitive light on the potential changes in NOX emissions under various operating conditions. The first part of this paper discusses the feasibility of ethanol as an alternative transportation fuel, including world production and ethanol production processes. The physicochemical properties of ethanol and gasoline are then compared to analyze their effects on combustion efficiency and exhaust emissions. Then, the pathways of NOX formation inside the cylinder of SI engines are discussed in depth. Finally, we review and critically discuss the effects of ethanol concentration in blends and different engine parameters on NOX formation.
{"title":"A review on the effects of ethanol/gasoline fuel blends on NOX emissions in spark-ignition engines","authors":"P. Iodice, A. Amoresano, Giuseppe Langella","doi":"10.18331/brj2021.8.4.2","DOIUrl":"https://doi.org/10.18331/brj2021.8.4.2","url":null,"abstract":"Ethanol can be used as an alternative fuel for spark-ignition (SI) engines to increase the octane number and oxygen content of ethanol/gasoline blends, thereby reducing dependence on fossil fuels and the exhaust emissions of incomplete combustion products. Although it is widely agreed that ethanol can reduce CO and HC exhaust emissions, the literature on ethanol and NOX emissions is far from conclusive; hence there is a need for an in-depth, updated review of ethanol/gasoline blends in SI engines and the relative production of NOX emissions. In light of that, the present work aims to provide a comprehensive literature review on the current state of ethanol combustion in SI engines to shed definitive light on the potential changes in NOX emissions under various operating conditions. The first part of this paper discusses the feasibility of ethanol as an alternative transportation fuel, including world production and ethanol production processes. The physicochemical properties of ethanol and gasoline are then compared to analyze their effects on combustion efficiency and exhaust emissions. Then, the pathways of NOX formation inside the cylinder of SI engines are discussed in depth. Finally, we review and critically discuss the effects of ethanol concentration in blends and different engine parameters on NOX formation.","PeriodicalId":46938,"journal":{"name":"Biofuel Research Journal-BRJ","volume":null,"pages":null},"PeriodicalIF":13.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43061814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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