The maritime industry is responsible for the emission of∼940 million tonnes of CO_(2) on an annual basis,accounting for roughly 2.9%of the total global anthropogenic greenhouse gas emissions.Achieving the decarboniza...The maritime industry is responsible for the emission of∼940 million tonnes of CO_(2) on an annual basis,accounting for roughly 2.9%of the total global anthropogenic greenhouse gas emissions.Achieving the decarbonization objectives set forth by the International Maritime Organization for the years 2030 and 2050 requires an expedited transition towards low-carbon marine fuel alternatives.This review presents a concentrated and quantitative assessment of biodiesel and biodiesel-alcohol blends as viable near-drop-in substitutes for marine gas oil.Non-edible feedstocks,including Jatropha curcas,Pongamia pinnata,used cooking oil,and microalgae,produce biodiesel with heating values ranging from 37 to 42 MJ kg^(−1) and cetane numbers between 47 and 58,thereby conforming to ISO 8217 specifications.The incorporation of alcohols,most notably n-butanol,in concentrations of 10-20%enhances atomization and ignition properties,resulting in a reduction of CO and hydrocarbon emissions by 50-60%and particulate matter by as much as 70%,accompanied by a modest increase in NOx emissions of 8-15%.A comprehensive meta-analysis of 18 studies representative of marine conditions has corroborated that blends containing 20%biodiesel and 10%-butanol-20%biodiesel maintain brake thermal efficiency(g=−0.03,P>0.05)while simultaneously decreasing CO,hydrocarbon,and particulate matter emissions by 16-21%.Lifecycle assessments reveal savings of greenhouse gas emissions ranging from 65 to 85%contingent upon the type of feedstock utilized.At the same time,techno-economic evaluations demonstrate that production costs are competitive with those of marine diesel,particularly when factoring in carbon credits.This review distinctively amalgamates statistical synthesis,insights from lifecycle and techno-economic assessments,and a strategic policy roadmap that aligns with the directives of the International Maritime Organization,the European Union Emissions Trading System,and various Asian maritime frameworks,thereby providing stakeholders with practical guidance for the large-scale implementation and adherence to the objectives of International Maritime Organization Tier III and carbon intensity indicator.展开更多
文摘The maritime industry is responsible for the emission of∼940 million tonnes of CO_(2) on an annual basis,accounting for roughly 2.9%of the total global anthropogenic greenhouse gas emissions.Achieving the decarbonization objectives set forth by the International Maritime Organization for the years 2030 and 2050 requires an expedited transition towards low-carbon marine fuel alternatives.This review presents a concentrated and quantitative assessment of biodiesel and biodiesel-alcohol blends as viable near-drop-in substitutes for marine gas oil.Non-edible feedstocks,including Jatropha curcas,Pongamia pinnata,used cooking oil,and microalgae,produce biodiesel with heating values ranging from 37 to 42 MJ kg^(−1) and cetane numbers between 47 and 58,thereby conforming to ISO 8217 specifications.The incorporation of alcohols,most notably n-butanol,in concentrations of 10-20%enhances atomization and ignition properties,resulting in a reduction of CO and hydrocarbon emissions by 50-60%and particulate matter by as much as 70%,accompanied by a modest increase in NOx emissions of 8-15%.A comprehensive meta-analysis of 18 studies representative of marine conditions has corroborated that blends containing 20%biodiesel and 10%-butanol-20%biodiesel maintain brake thermal efficiency(g=−0.03,P>0.05)while simultaneously decreasing CO,hydrocarbon,and particulate matter emissions by 16-21%.Lifecycle assessments reveal savings of greenhouse gas emissions ranging from 65 to 85%contingent upon the type of feedstock utilized.At the same time,techno-economic evaluations demonstrate that production costs are competitive with those of marine diesel,particularly when factoring in carbon credits.This review distinctively amalgamates statistical synthesis,insights from lifecycle and techno-economic assessments,and a strategic policy roadmap that aligns with the directives of the International Maritime Organization,the European Union Emissions Trading System,and various Asian maritime frameworks,thereby providing stakeholders with practical guidance for the large-scale implementation and adherence to the objectives of International Maritime Organization Tier III and carbon intensity indicator.
