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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Interactive effects of salinity, redox, and colloids on greenhouse gas production and carbon mobility in coastal wetland soils

Coastal wetlands, including freshwater systems near large lakes, rapidly bury carbon, but less is known about how they transport carbon either to marine and lake environments or to the atmosphere as greenhouse gases (GHGs) such as carbon dioxide and methane. This study examines how GHG production and organic matter (OM) mobility in coastal wetland soils vary with the availability of oxygen and other terminal electron acceptors. We also evaluated how OM and redox-sensitive species varied across different size fractions: particulates (0.45–1μm), fine colloids (0.1–0.45μm), and nano particulates plus truly soluble (<0.1μm; NP+S) during 21-day aerobic and anaerobic slurry incubations. Soils were collected from the center of a freshwater coastal wetland (FW-C) in Lake Erie, the upland-wetland edge of the same wetland (FW-E), and the center of a saline coastal wetland (SW-C) in the Pacific Northwest, USA. Anaerobic methane production for FW-E soils were 47 and 27,537 times greater than FW-C and SW-C soils, respectively. High Fe 2+ and dissolved sulfate concentrations in FW-C and SW-C soils suggest that iron and/or sulfate reduction inhibited methanogenesis. Aerobic CO 2 production was highest for both freshwater soils, which had a higher proportion of OM in the NP+S fraction (64±28% and 70±10% for FW-C and FW-E, respectively) and organic C:N ratios reflective of microbial detritus (5.3±5.3 and 5.3±7.0 for FW-E and FW-C, respectively) compared to SW-C, which had a higher fraction of particulate (58±9%) and fine colloidal (19±7%) OM and organic C:N ratios reflective of vegetation detritus (11.4 ± 1.7). The variability in GHG production and shifts in OM size fractionation and composition observed across freshwater and saline soils collected within individual and across different sites reinforce the high spatial variability in the processes controlling OM stability, mobility, and bioavailability in coastal wetland soils.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Review of Experimental Decontamination Factors (DF) of Iodine in the Pilot-Scale Law Melter Off-Gas Systems

The Low Activity Waste (LAW) melters at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will convert low-activity tank wastes containing high concentrations of sodium salts into glass for onsite disposal. Much of the airborne particulates during the calcination/fusion of the feed solids will be removed by condensation and scrubbing of the melter exhaust in the Submerged Bed Scrubber (SBS) and Wet Electrostatic Precipitator (WESP)of the primary off-gas treatment system. The gases exiting the WESP enter a secondary off-gas treatment system, which includes a High-Efficiency Particulate Air (HEPA) filter, an activated carbon absorber, a Thermal Catalytic Oxidizer (TCO), a Selective Catalytic Reduction (SCR) unit, a caustic scrubber, and an exhauster. Much of the volatile organics and NOx will be removed in the TCO and SCR, respectively. Under WTP Direct Feed LAW (DFLAW) configuration, the liquid effluents from the SBS and WESP will be collected and evaporated under vacuum with the evaporator concentrate recycled back to the LAW melter, while the evaporator condensate will be merged with the caustic scrubber solution and sent to the Effluent Treatment Facility (ETF).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

MIXv2: a long-term mosaic emission inventory for Asia (2010–2017)

The MIXv2 Asian emission inventory is developed under the framework of the Model Inter-Comparison Study for Asia (MICS-Asia) Phase IV and produced from a mosaic of up-to-date regional emission inventories. We estimated the emissions for anthropogenic and biomass burning sources covering 23 countries and regions in East, Southeast and South Asia and aggregated emissions to a uniform spatial and temporal resolution for seven sectors: power, industry, residential, transportation, agriculture, open biomass burning and shipping. Compared to MIXv1, we extended the dataset to 2010–2017, included emissions of open biomass burning and shipping, and provided model-ready emissions of SAPRC99, SAPRC07, and CB05. A series of unit-based point source information was incorporated covering power plants in China and India. A consistent speciation framework for non-methane volatile organic compounds (NMVOCs) was applied to develop emissions by three chemical mechanisms. The total Asian emissions for anthropogenic/open biomass sectors in 2017 are estimated as follows: 41.6/1.1 Tg NO x , 33.2/0.1 Tg SO 2 , 258.2/20.6 Tg CO, 61.8/8.2 Tg NMVOC, 28.3/0.3 Tg NH 3 , 24.0/2.6 Tg PM 10 , 16.7/2.0 Tg PM 2.5 , 2.7/0.1 Tg BC (black carbon), 5.3/0.9 Tg OC (organic carbon), and 18.0/0.4 Pg CO 2 . The contributions of India and Southeast Asia were emerging in Asia during 2010–2017, especially for SO 2 , NH 3 and particulate matter. Gridded emissions at a spatial resolution of 0.1° with monthly variations are now publicly available. This updated long-term emission mosaic inventory is ready to facilitate air quality and climate model simulations, as well as policymaking and associated analyses.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2010

Tidal Marsh Outwelling of Dissolved Organic Matter and Resulting Temporal Variability in Coastal Water Optical and Biogeochemical Properties

Coastal wetlands are highly dynamic environments at the land-ocean interface where human activities, short-term physical forcings and intense episodic events result in high biological and chemical variability. Long being recognized as among the most productive ecosystems in the world, tidally-influenced coastal marshes are hot spots of biogeochemical transformation and exchange. High temporal resolution observations that we performed in several marsh-estuarine systems of the Chesapeake Bay revealed significant variability in water optical and biogeochemical characteristics at hourly time scales, associated with tidally-driven hydrology. Water in the tidal creek draining each marsh was sampled every hour during several semi-diurnal tidal cycles using ISCO automated samplers. Measurements showed that water leaving the marsh during ebbing tide was consistently enriched in dissolved organic carbon (DOC), frequently by more than a factor of two, compared to water entering the marsh during flooding tide. Estimates of DOC fluxes showed a net DOC export from the marsh to the estuary during seasons of both low and high biomass of marsh vegetation. Chlorophyll amounts were typically lower in the water draining the marsh, compared to that entering the marsh during flooding tide, suggesting that marshes act as transformers of particulate to dissolved organic matter. Moreover, detailed optical and compositional analyses demonstrated that marshes are important sources of optically and chemically distinctive, relatively complex, high molecular weight, aromatic-rich and highly colored dissolved organic compounds. Compared to adjacent estuarine waters, marsh-exported colored dissolved organic matter (CDOM) was characterized by considerably stronger absorption (more than a factor of three in some cases), larger DOC-specific absorption, lower exponential spectral slope, larger fluorescence signal, lower fluorescence per unit absorbance, and higher fluorescence at visible wavelengths. Observed patterns in water optical and biogeochemical variables were very consistent among different marsh systems and throughout the year, despite continued tidal exchange, implying rapid transformation of marsh DOM in the estuary through both photochemical and microbial processes. These findings illustrate the importance of tidal marsh ecosystems as sources, sinks and/or transformers of biologically important nutrients, carbon and colored dissolved organic compounds, and their influence on short-term biological, optical and biogeochemical variability in coastal waters.

Tzortziou, Maria↗
DOE OSTI2020

Combined electrocoagulation-microfiltration-membrane distillation for treatment of hydraulic fracturing produced water

Hydraulic fracturing flowback and produced water is a highly impaired wastewater containing dissolved salts polar and non-polar organic compounds, oil and surfactants. Here a combined electrocoagulation - microfiltration – membrane distillation process has been used to treat this wastewater. Electrocoagulation followed by microfiltration was used to pretreat the wastewater prior membrane distillation. The initial total dissolved solids (TDS) concentration was extremely high being 245,300 mg L -1 . After electrocoagulation, the total organic carbon (TOC) was reduced from 120 mg L -1 to 64 mg L -1 . Tangential flow microfiltration using a 0.1 μm pore size polyethersulfone membrane was used to separate the particulate matter after electrocoagulation and to further reduce the TOC to 44 mg L -1 . Membrane distillation was used to desalinate the pretreated produced water resulting in a high quality treated water (TDS of 56 mg L -1 and TOC 1 mg L -1 ). Three membranes with very different surface morphology were used: commercially available polyvinylidene fluoride, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers and multiwalled carbon nanotube coated polytetrafluoroethylene. The TDS in the retentate increased to over 350,000 mg L -1 . During membrane distillation, the temperature of the feed tank was maintained at 36 °C while the feed entered the module at 60 °C in order to minimize scaling on the membrane. The surface properties of an ideal membrane that is resistant to wetting and provides high flux is likely to depend on the TDS and properties of the wastewater.

42 ENGINEERING↗
DOE OSTI2022

Formation of carbon and oxygen rich surface layer on high purity magnesium by atmospheric carbon dioxide plasma

Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO 2 atmospheric plasma (CO 2 -AP) process. The reactive CO 2 -AP interacts with the Mg surface and forms a unique layered structure with the top MgCO 3 /MgO-intermixed particulates pillars and the bottom dense layer. The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules, plasma-active CO 2 molecules, and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer. The resulting surfaces after CO 2 -AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion. For the hydrophobic surfaces of CO 2 -AP treated Mg, molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source. The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment, generation of by-product, and supply of raw material.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Well-to-Wheels Analysis of Zero-Emission Plug-In Battery Electric Vehicle Technology for Medium- and Heavy-Duty Trucks

Conventional diesel medium- and heavy-duty vehicles (MHDVs) create large amount of air emissions. With the advancement in technology and reduction in the cost of batteries, plug-in battery electric vehicles (BEVs) are increasingly attractive options for improving energy efficiency and reducing air emissions of MHDVs. In this paper, we compared the well-to-wheels (WTW) greenhouse gases (GHGs) and criteria air pollutant emissions of MHD BEVs with their conventional diesel counterparts across weight classes and vocations. We expanded the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET) model to conduct the WTW analysis of MHDVs. The fuel economy for a wide range of MHDV weight classes and vocations, over various driving cycles, was evaluated using a high-fidelity vehicle dynamic simulation software (Autonomie). The environmental impacts of MHD BEVs are sensitive to the source of electricity used to recharge their batteries. The WTW results show that MHD BEVs significantly improve environmental sustainability of MHDVs by providing deep reductions in WTW GHGs, nitrogen oxides, volatile organic compounds, and carbon monoxide emissions, compared to conventional diesel counterparts. Increasing shares of renewable and natural gas technologies in future national and regional electricity generation are expected to reduce WTW particulate matters and sulfur oxide emissions for further improvement of the environmental performance of MHD BEVs.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, and Potential Trajectories of Future Change

Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice-rich moraine, and organic-rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO 2 (25%) dominated. In watersheds affected by thaw-induced mass wasting, erosion of ice-rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw-induced wasting was, on average, equivalent to 6–16% of estimated net ecosystem exchange (NEE). Finally, in watersheds affected by thaw-induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Biochemical Conversion of Herbaceous Biomass to Renewable Diesel: Net Greenhouse Gas and Air Pollutant Trade-offs

This study examines greenhouse gas (GHG) and criteria air pollutant (CAP) emissions trade-offs for renewable diesel across 12 scenarios, involving different biochemical conversion designs, biorefinery scales, and feedstocks. A conventional design uses lignin for on-site heat and power, which exports excess power to the grid. An alternative design exports lignin pellets, offsetting other pellet production methods but requiring grid electricity to meet biorefinery power demands. Net emissions were quantified in Iowa and Georgia, selected considering feedstock availability, coproduct displacement, and regional power grids, assuming grid-exported power avoids coal or low-carbon electricity. Results for the conventional design remained consistent across the electricity displacement scenarios. When comparing lignin utilization strategies, pelletizing lignin reduces sulfur dioxide, carbon monoxide, nitrogen oxides, and volatile organic compounds (net emissions –0.66 mg MJ –1 , 25 mg MJ –1 , 25 mg MJ –1 , 7.8 mg MJ –1 , respectively). However, lignin pelletization increases net particulate matter (fine and coarse) and ammonia (net emissions of 4.7 mg MJ –1 , 13 mg MJ –1 , and 0.26 mg MJ –1 , respectively), alongside indirect GHG emissions due to grid electricity dependence. Additionally, processing 2000 tonnes corn stover daily minimizes emissions for both designs. Only lignin pelletization with renewable electricity and additional particulate matter and ammonia controls reduces all CAP and GHG emissions simultaneously.

09 BIOMASS FUELS↗
NASA NTRS2023

The Projected Future Degradation in Air Quality is Caused by More Abundant Natural Aerosols in a Warmer World

Previous studies suggest that greenhouse gas-induced warming can lead to increased fine particulate matter concentrations and degraded air quality. However, significant uncertainties remain regarding the sign and magnitude of the response to warming and the underlying mechanisms. Here, we show that thirteen models from the Coupled Model Intercomparison Project Phase 6 all project an increase in global average concentrations of fine particulate matter in response to rising carbon dioxide concentrations, but the range of increase across models is wide. The two main contributors to this increase are increased abundance of dust and secondary organic aerosols via intensified West African monsoon and enhanced emissions of biogenic volatile organic compounds, respectively. Much of the inter-model spread is related to different treatment of biogenic volatile organic compounds. Our results highlight the importance of natural aerosols in degrading air quality under current warming, while also emphasizing that improved understanding of biogenic volatile organic compounds emissions due to climate change is essential for numerically assessing future air quality.

Climate and Earth system modelling↗
DOE OSTI2022

Simulation of anoxic lenses as exporters of reactivity in alluvial aquifer sediments

Sedimentary interfaces between contrasting hydrogeological facies in alluvial aquifers drive the development of biogeochemical interfaces that influence subsurface and surface water quality. Here, we calibrate a reactive transport model on a series of dual-domain column experiments, where centimeter-scale, low-permeability, organic-rich anoxic lenses are embedded in coarser-grained aquifer material. Simulations explicitly account for C, Fe, and S cycling at the interface between the lenses and the aquifer in water-saturated conditions. Our results highlight the role of fine-grained, organic-rich inclusions not only as sources or sinks for redox-sensitive species, but also as exporters of nutrients that stimulate downgradient biogeochemical cycling. By releasing large amounts of organic carbon into the surrounding aquifer, such lenses drive the development of proximal secondary reduction zones ("halos"), characterized by high microbial activity (e.g., sulfate reduction) and accumulation of reduced reaction products (e.g., iron sulfide). If similar secondary reduction zones develop within the hydraulically conductive domain of an aquifer, they would be highly susceptible to changes in hydrologic conditions, for instance oxygen pulses associated with seasonal snowmelt. Furthermore, our results also emphasize the limitations of relying solely on aqueous species measurements to inform reactivity in systems where fast redox cycling and/or sizeable particulate transport may limit the signature of reactivity in the dissolved phase.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Particulate organic matter (POM) transport and transformation at the terrestrial-aquatic interface (Final Report)

This project investigates the input, transport, and degradation of particulate organic matter (POM) in near-surface riverbed sediments at the Hanford 300 Area of the Columbia River, a dynamic, regulated river system influenced by upstream dam operations. Riverbed sediments are biogeochemical hot spots where organic carbon inputs stimulate intense microbial activity, affecting nutrient cycling and redox transformations in the hyporheic zone (HZ). While dissolved organic matter (DOM) cycling has been studied extensively, little is known about the infiltration and transformation of POM—particularly under variable flow regimes common in large, regulated rivers.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2018

Li-ion 18650 Thermal Runaway Particulate Analysis

Three types of atmospheres were tested for their effects on the particulates generated in a lithium ion (Li-ion) battery thermal runaway. Normal laboratory air (Ambient), a mixture of 23.5% O2/76.5% N2 meant to simulate the atmosphere on the International Space Station (ISS), and Vacuum environments were tested. Samsung 26F 18650 cells were driven to thermal runaway using heater tape, and the resultant particulates were collected analyzed using SEM/EDX, FTIR, GCMS, as well as conductivity and magnetic probes. All three conditions generated dense black particulate films composed of very fine carbon and metal particles. These films, however, were not very conductive, though individual particulates would be, and the particles demonstrated weak paramagnetism. FTIR and GCMS identified a substantial amount of volatile components in the particulate films, both organic partial combustion products, but also electrolyte salt products.

Nemanick, E. Joseph↗
DOE OSTI2020

Environmental impact of national and subnational carbon policies in China based on a multi-regional dynamic CGE model

Carbon policies are important not only for mitigating global climate change, but also for controlling local and regional air pollution. The large regional disparities in economic development and air pollution across China calls for regionally differentiated policies. Previous studies have not systematically investigated the environmental impacts of regional carbon policies in China covering different spatial scales. This study constructs a multi-regional dynamic computable general quilibrium (CGE) model covering 30 provinces of China to assess the impacts of national and subnational carbon polices on CO2 emissions and co-emitted air pollutants from 2020 to 2050. We consider one national carbon policy which aims to achieve China’s 2030 national CO2 abatement target, as well as three regional policies with the same policy stringency as the national one but only applied to eastern China (EP), the Jiangsu-Shanghai-Zhejiang area (JSZP), and the Beijing-Tianjin-Hebei area (BTHP), respectively. We find that regional policies (EP, JSZP, and BTHP) are as effective in reducing CO2 emissions in their targeted regions as the national policy. However, they lead to an increase in CO2 emissions in untargeted regions (the so-called “emissions leakage”). The CO2 leakage rates, which depend on the policy spatial coverage, are 4%, 13%, and 65% for EP, JSZP, and BTHP, respectively, in 2050. Compared with CO2, changes in air pollutant emissions, including sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOC), and fine particulate matter (PM2.5), exhibit a similar pattern under all policy scenarios, but the magnitude of change is significantly smaller. Transportation, thermal power, and some energy intensive industries are the three largest contributors to CO2 and air pollutant emission reductions. Our results suggest that regional carbon policy is effective in reducing CO2 and air pollutant emissions in the targeted regions, and extending the spatial coverage or increasing policy stringency can largely inhibit emissions leakage.

Zhang, Wenwen↗
DOE OSTI2026

Soil Organic Matter Stabilization by Polyvalent Cations in a Buried Alkaline Soil

Buried paleosols can store large quantities of organic carbon (C), much of which persists for millennia due to isolation from surface processes that promote decomposition. Subsoil organic matter (SOM) persistence is often enhanced by mineral associations and ionic conditions—particularly high clay content and polyvalent cations—that limit microbial degradation and leaching. However, the vulnerability of these deep C stocks under erosion or environmental change remains poorly understood. This study investigates controls on SOM stabilization in the Brady paleosol and overlying modern soils across contrasting geomorphic settings in the Great Plains of Nebraska where Late Quaternary loess deposition and erosion created a sequence of buried and exposed paleosols. We sampled soils along burial and erosional toposequences and analyzed their physicochemical properties and radiocarbon‐based persistence of occluded particulate organic matter (oPOM) and mineral fractions (MF). Brady paleosol showed greater persistence (lower Fm) of oPOM and MF than modern soils, particularly under burial. This was linked to higher silt and clay content, elevated electrical conductivity, and increased exchangeable calcium and magnesium content, supporting roles for organo‐mineral interactions, flocculation, and carbonate cementation. In modern soils, SOM persistence and C content were more strongly tied to pH and cation exchange capacity. Erosional exposure reduced SOM stability and promoted geochemical convergence toward modern surface soils. These findings show that burial enhances SOM persistence via multiple stabilization mechanisms, while erosion increases subsoil C vulnerability. Our results underscore the importance of geomorphic and geochemical context in predicting soil C stability under environmental change.

Environmental sciences↗
NASA NTRS2014

Chemistry Characterization of Jet Aircraft Engine Particulate by XPS: Results from APEX III

This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear.

soot↗
DOE OSTI2020

Soil aggregate-mediated microbial responses to long-term warming

Soil microbial carbon use efficiency (CUE) is a combination of growth and respiration, which may respond differently to climate change depending on physical protection of soil carbon (C) and its availability to microbes. In a mid-latitude hardwood forest in central Massachusetts, 27 years of soil warming (+5 °C) has resulted in C loss and altered soil organic matter (SOM) quality, yet the underlying mechanisms remain unclear. In this work, we hypothesized that long-term warming reduces physical aggregate protection of SOM, microbial CUE, and its temperature sensitivity. Soil was separated into macroaggregate (250–2000 μm) and microaggregate (<250 μm) fractions, and CUE was measured with 18 O enriched water (H 2 18 O) in samples incubated at 15 and 25 °C for 24 h. We found that long-term warming reduced soil C and nitrogen concentrations and extracellular enzyme activity in macroaggregates, but did not affect physical protection of SOM. Long-term warming showed little effect on CUE or microbial biomass turnover time because it reduced both growth and respiration. However, CUE was less temperature sensitive in macroaggregates from the warmed compared to the control plots. Our findings suggest that microbial thermal responses to long-term warming occur mostly in soil compartments where SOM is less physically protected and thus more vulnerable to microbial degradation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Sustainable Biofuels for Low-Carbon Maritime Transportation

The marine shipping sector heavily depends on fossil fuels and is one of the largest petroleum fuel consumers [1,2]. The annual global marine fuel consumption was estimated to be around 400 million metric tons in 2019 (2.5 billion barrels). Moreover, ocean shipping is one of the most significant contributors to sulfur oxides, nitrogen oxides, and particulate matter emissions. Global shipping contributes 13% of human-caused sulfur emissions and 2.6% of anthropogenic carbon dioxide emissions. As a major source of pollutant emissions, the marine industry faces several challenges related to emission regulations. The International Maritime Organization (IMO) has established a framework for reducing the carbon intensity of shipping: 40% reduction relative to 2008 levels by 2030 and 70% reduction by 2050. As the aviation sector, the maritime shipping sector is difficult to decarbonize through electrification. Biofuels offer the best opportunities for decarbonizing marine shipping in the near and medium-term. Advanced biofuels such as pyrolysis bio-oil offer the low-cost potential for meeting carbon reduction goals. For instance, the pyrolysis bio-oil exhibited promising marginal CO2 abatement costs at less than $100/tonne CO2-equivalent at a heavy fuel oil price greater than $1.10/gal [1]. As a potential biofuel option for low-carbon maritime shipping, this presentation focuses on a comparative techno-economic analysis (TEA) of bio-oils produced via a fast pyrolysis-based conversion pathway. The pathway converts a 50/50 blend of forest residues and clean pine to bio-oil via three process options: fast pyrolysis without vapor upgrading, and fast pyrolysis with vapor phase upgrading over ZSM-5 zeolite catalyst and Pt/TiO2 catalyst. The process configuration and operation variation led to different capital and operating costs, as well as the resulting raw bio-oil’s yield and quality, e.g., the water content, total acid number, and carboxylic acid number. The study also determined the minimum upgrading of bio-oils required to enable blending with very low sulfur fuel oil (VLSFO), with the associated costs reflected in TEA. This study shows that bio-oil could be a cost-effective fuel option for decarbonizing maritime shipping. Further research is required with respect to biofuel blending properties, such as compatibility with existing fuel system infrastructure and suitable engine performance.

BIOMASS FUELS↗