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Catalytic hydrothermolysis (CH) is a sustainable aviation fuel (SAF) pathway that has been recently approved for use in aircraft fuel production. In alignment with broader sustainable aviation goals, SAF production through CH requires a quantitative assessment of carbon intensity (CI) impacts. In this study, a current‐day life‐cycle analysis (LCA) was performed on SAF produced via CH to determine the CI. Various oily feedstocks were considered, including vegetable oils (soybean, carinata, camelina and canola) and low‐burden oils and greases (corn oil, yellow grease and brown grease). Life‐cycle inventory data were collected on all processes within the CH LCA boundary: feedstock cultivation and/or collection, preprocessing, hydrothermal cleanup and CH, biocrude refining, fuel transportation and end use through combustion. Baseline results show that the CH‐produced SAF can be generated with CI reductions ranging from 48 to 82% compared with conventional jet fuel. Modest improvements to CI can be achieved through incremental changes to the brown grease CH process, such as relaxing the dewatering specification and implementing renewable natural gas and electricity, which could decrease the CI from 22.9 to 7.9 g CO2e/MJ. Total CH fuel production potential was also assessed on the basis of current or near‐future feedstock availability and CI. The total biofuel production potential of CH (SAF and renewable fuel co‐products) in the US sums to approximately 3487 million gallons per year, with 97% of these volumes having a CI below 50% of that for petroleum jet fuel. The study shows that from an LCA perspective, CH offers a viable SAF pathway that is comparable with existing SAF pathways like hydroprocessed esters and fatty acids. [ABSTRACT FROM AUTHOR]

This study evaluates how low‐carbon production technologies applicable to ethanol plants may reduce the life‐cycle greenhouse gas emission (GHG) intensities of corn ethanol production in the USA. Results indicate that options focusing on incremental energy efficiency (e.g., combined heat and power) and yield improvements have a limited impact on GHG reductions. To achieve deep decarbonization (>50% GHG reduction compared to current corn ethanol production), a fuel switch from natural gas (NG) to alternative low‐carbon fuels is needed. Replacing 50% of NG demand at ethanol plants with syngas from biomass through gasification or renewable natural gas from animal waste could achieve significant GHG reductions (11.7–23.5 g CO2e/MJ ethanol). Adding multiple technologies, including carbon capture and storage, to existing ethanol plants may further reduce GHG emissions to −18.4 g CO2e MJ−1 ethanol (including land‐use change emissions), which is 120% lower than the carbon intensity of pure gasoline. These results could inform how the ethanol industry could move toward net‐zero ethanol production. © 2022 UChicago Argonne, LLC, Operation of Argonne National Laboratory. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

meso‐Carboxyl‐BODIPY responds to small electronic changes resulting from acyl substitution reactions with a marked change in fluorescence. Herein, the minute changes that accompany the thioester to amide conversion encountered in native chemical ligation (NCL) are exploited in the construction of fluorescent "turn‐on" probes. Two fluorogenic probes, 1 a and 4, derived from a meso‐thioester‐BODIPY scaffold, were designed for the selective detection of cysteine (1 a) and aminopeptidase N (4), respectively. The aromatic (1 a) and aliphatic (4) thioesters of meso‐carboxyl‐BODIPY are nonfluorescent. However, specific analyte‐induced conversion to the meso‐amide derivative caused significant spectral changes and a dramatic fluorescence enhancement. Probe 1 a exhibited a large fluorescence "turn‐on" response with high selectivity toward cysteine via a tandem NCL reaction. Probe 4 was successfully applied to the monitoring and imaging of endogenous aminopeptidase N in live cancer cells. [ABSTRACT FROM AUTHOR]

Since 2000, corn ethanol production in the USA has increased significantly – from 1.6 to 15 billion gallons (6.1 to 57 billion liters) – due to supportive biofuel policies. In this study, we conduct a retrospective analysis of the changes in US corn ethanol greenhouse gas emission intensity, sometimes known as carbon intensity (CI), over the 15 years from 2005 to 2019. Our analysis shows a significant decrease in CI: from 58 to 45 gCO2e/MJ of corn ethanol (a 23% reduction). This is due to several factors. Corn grain yield has increased continuously, reaching 168 bushels/acre (10.5 metric tons/ha, a 15% increase) while fertilizer inputs per acre have remained constant, resulting in decreased intensities of fertilizer inputs (e.g., 7% and 18% reduction in nitrogen and potash use per bushel of corn grain harvested, respectively). A 6.5% increase in ethanol yield, from 2.70 to 2.86 gal/bushel corn (0.402 to 0.427 L kg−1 corn), and a 24% reduction in ethanol plant energy use, from 32 000 to 25 000 Btu/gal ethanol (9.0 to 6.9 MJ L−1 ethanol) also helped reduce the CI. The total GHG emission reduction benefits through the reduction in the CI and increased ethanol production volume are estimated at 140 million metric tons (MMT) from 2005 to 2019 in the ethanol industry. Displacement of petroleum gasoline by corn ethanol in the transportation fuel market resulted in a total GHG emission reduction benefit of 544 MMT CO2e during the period 2005 to 2019. © 2021 Argonne National Laboratory. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

The emission spectrum of BODIPY in PMMA is reasonably reproduced by the progression of the single mode with the vibrational energy of 0.11 eV (Figure 1(b)). (c) The emission spectrum of BODIPY nanowire is decomposed into the progression of single mode (green). In summary, the optical properties of BODIPY are investigated in the nanowire shapes of aggregates, where the quantum yield is enhanced by the aggregation-induced emission. In this Communication, we report the optical properties of BODIPY nanostructures, where the aggregation-induced emission enhances the quantum yield. [Extracted from the article]

Corn ethanol plants generate high‐purity carbon dioxide (CO2) while producing ethanol. If that CO2 could be converted into ethanol by carbon capture and utilization technologies it would be possible to increase ethanol production more than 37% without additional corn grain inputs. Gas fermentation processes use microbes to convert carbon‐containing gases into ethanol and so have the potential to be used with the CO2 from biorefineries for this purpose. However, as CO2 utilization technologies for converting thermodynamically stable CO2 are typically energy intensive, it is necessary to evaluate the related life‐cycle greenhouse gas (GHG) emissions (carbon intensities or CIs) to see whether there are actual emission reduction benefits. In this study, we evaluate the CIs of ethanol produced from high‐purity CO2 in corn ethanol plants by gas fermentation plus electrochemical reduction. Our analysis shows that the sources of electricity and hydrogen are key drivers of CO2‐based ethanol's GHG emissions. With wind electricity, the design cases show the potential of near‐zero CI ethanol (1.1 g CO2e/MJ), but that can increase to up to 331–531 g CO2e/MJ when today's U.S. Midwest electricity mix is used. To avoid the renewable electricity intermittency issue, we considered a power purchase agreement option using wind electricity 40% of the time and using the regional mix for the rest, which provides a 42% GHG emission reduction from the CI of gasoline. © 2020 The Authors and UChicago Argonne, LLC, Operator of Argonne National Laboratory. Biofuels, Bioproducts and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The analyte‐directed formation of emissive J‐aggregates of a meso‐ester BODIPY dye is explored in the design of fluorescence "light‐up" probes. The heparin‐specific pyridinium‐functionalized meso‐ester BODIPY dye C10‐Py+ self‐assembles in aqueous buffer into spherical aggregated nanostructures with spectroscopic features indistinguishable from the monomeric dye (signal off). In the presence of heparin, the aggregated assemblies rearrange and associate with heparin through charge‐pairing interactions, triggering the spontaneous formation of emissive J‐type aggregates (signal on). The heparin‐induced J‐aggregate formation of C10‐Py+ provides an excellent "turn‐on" signal with large spectral shifts. The response is highly selective for heparin over other closely related glycosaminoglycan (GAG) analogues, sensitive, fast, and operationally simple. Assays for heparin in human serum, and for the adulterant OSCS in heparin are demonstrated, confirming the reliability and robustness of the J‐aggregation approach using meso‐ester BODIPY dyes in the design of aggregation‐induced emission (AIE)‐based fluorogenic probes. [ABSTRACT FROM AUTHOR]

Abstract Energy production typically consumes a large amount of fresh water, which is a critical resource for both human and ecosystem needs. Robust water impact analysis is prudent prior to deploying new energy systems at scale. While there are many water indices representing relative water availability (or scarcity), they are not suitable for analyzing the impact of consumptive water in the context of life-cycle analysis (LCA). The available water remaining (AWARE) concept, developed by the Water Use in LCA Group, enables global water impact analysis (AWARE-Global). However, while AWARE-Global enables consistent comparison internationally, it lacks the high spatial resolution and fidelity needed for decision-making at the local level regarding energy system deployment within the United States (U.S.). In this study, we developed an AWARE system for applications in the contiguous U.S. (AWARE-US) by incorporating measured runoff and human water use data at U.S. county-level resolution. Results of AWARE-US quantify the water stress and the impacts of increase in water consumption in various regions within the U.S. To demonstrate the potential use of AWARE-US, we evaluated the impacts of a potential hydrogen fuel cell electric vehicle deployment scenario on the regional water stress in various regions within the U.S. Graphical abstract Unlabelled Image Highlights • A water scarcity index is developed by using measured high-spatial-resolution data. • AWARE-US can be used to analyze impact of regional water use of new energy systems. • Water impact and water footprint differ in energy sustainability assessments. • Water scarcity footprint can help guide regional deployment of new energy systems. [ABSTRACT FROM AUTHOR]

Sewage sludge from wastewater treatment facilities needs to be treated before it can be disposed of. While it is typically processed through an anaerobic digestion process, sludge can also be a good feedstock for alternative fuel production. High-temperature steam gasification is a process that decomposes organic materials into synthesis gas (syngas) with a high hydrogen concentration. In this study, a lab-scale steam gasification system which converts sewage sludge into valuable syngas was developed and experimentally evaluated. This study specifically focuses on investigating the chemical kinetics of syngas generation and feedstock decomposition in a batch process. The syngas generation rates and concentrations of syngas constituents were measured, and changes in carbon balance during gasification were tracked with respect to time, which shows how reaction rates vary over time. It was found that variations in steam flow rates modified the gasification reactions both thermodynamically and hydrodynamically. The gasification processes were fitted into logistics curves to understand the effects of different steam flow rates. The results indicate that the chemical reaction velocity can be controlled to achieve optimum operating conditions, which potentially can reduce both processing time and steam consumption while maximizing the syngas yield. This study would contribute more to the complete understanding of the sewage sludge gasification processes and the kinetics of the gasification chemical reactions. [ABSTRACT FROM AUTHOR]

Various waste-to-energy (WTE) conversion technologies can generate energy products from municipal solid waste (MSW). Accurately evaluating landfill gas (LFG, mainly methane) emissions from base case landfills is critical to conducting a WTE life-cycle analysis (LCA) of their greenhouse gas (GHG) emissions. To reduce uncertainties in estimating LFG, this study investigated key parameters for its generation, based on updated experimental results. These results showed that the updated parameters changed the calculated GHG emissions from landfills significantly depending on waste stream; they resulted in a 65% reduction for wood (from 2412 to 848 t CO 2 e/dry t) to a 4% increase for food waste (from 2603 to 2708 t CO 2 e/dry t). Landfill GHG emissions also vary significantly based on LFG management practices and climate. In LCAs of WTE conversion, generating electricity from LFG helps reduce GHG emissions indirectly by displacing regional electricity. When both active LFG collection and power generation are considered, GHG emissions are 44% less for food waste (from 2708 to 1524 t CO 2 e/dry t), relative to conventional MSW landfilling. The method developed and data collected in this study can help improve the assessment of GHG impacts from landfills, which supports transparent decision-making regarding the sustainable treatment, management, and utilization of MSW. [ABSTRACT FROM AUTHOR]

Non-recyclable municipal solid waste (MSW) can be used as feedstock for liquid fuel production via gasification followed by Fischer-Tropsch (FT) processes. Given the heterogeneity of MSW material composition and variation in material properties, its convertibility to liquid hydrocarbon fuels could vary widely, affecting the sustainability of utilizing non-recyclable MSW for fuel production. This study evaluates the life cycle greenhouse gas (GHG) emissions (carbon intensities [CIs]) of FT fuels from non-recyclable MSW. Key issues that could greatly affect the CIs were examined, including fossil carbon content of the MSW, emission implications of diverting non-recyclable MSW from landfills to fuel production, and conversion efficiency. Results show that the CIs of fuels produced from various waste streams range 80–105 gCO 2 e/MJ, which may exceed the CI of petroleum fuels. Higher fossil carbon content in the MSW feedstock tends to incur higher GHG emissions as biogenic carbon emissions are considered carbon neutral. Meanwhile, diverting different fractions of non-recyclable MSW, such as food waste and low-quality paper, from landfills may result in GHG emissions that may include the potential avoidance of methane emissions and potential sequestration of biogenic carbon that is foregone. To reduce GHG emissions, a carbon capture and sequestration option in the fuel production stage is considered, which could reduce the CI by 53–64 gCO 2 e/MJ. Carbon fates of different non-recyclable MSW in landfills are further evaluated to determine how they vary and impact the CIs of MSW-derived fuels. • Evaluated carbon intensities of liquid fuels produced from municipal solid waste. • Considered the impact of avoided business-as-usual (BAU) landfill cases. • Waste-derived fuels may not present emission reduction compared to fossil fuels. • Fossil carbon emissions and avoided BAU contribute to the carbon intensities. • Carbon capture and sequestration reduces the carbon intensity of MSW-derived fuels. [ABSTRACT FROM AUTHOR]

A steam gasification processes is an energy conversion pathway through which organic materials are converted to useful energy. In spite of the high energy content in organic waste materials, they have been mostly disposed of in landfills, which causes harmful environmental issues such as methane emissions and ground water pollution and contaminations. In this sense, organic solid waste materials are regarded as alternative resources for conversion to useful energy in the steam gasification process. In this study, three types of waste materials - municipal solid waste (MSW), used tires and sewage sludge - were used to generate syngas through the gasification process in a 1000 °C steam atmosphere. The syngas generation rates and its chemical compositions were measured and evaluated over time to determine the characteristics and dynamics of the gasification process. Also, carbon conversion, and mass and energy balances are presented which demonstrates the feasibility of steam gasification as a waste conversion pathway. The results show that the syngas contains high concentrations of H2, around 41-55% by volume. The syngas generation rate was found to depend on the carbon content in the feedstock regardless of the types of input materials. Comparing to the hydrogen production from water splitting that requires extremely high temperatures at around 1500 °C, hydrogen production by steam gasification of organic materials can be regarded as equally effective but requires lower system temperatures. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the characteristics of woody biomass conversion to syngas using a steam allothermal gasification process. The entering steam maintained at 877 °C and 1000 °C, respectively was used as the gasifying agent. A lab scale apparatus was built to perform the gasification experiment and the produced syngas was accurately analyzed using gas chromatography. The results clearly indicate that the syngas from steam gasification contains relatively higher H 2 concentrations, and the heating values of the syngas reach 9–10 MJ/m 3 . A thermodynamic equilibrium thermochemical model that accounts for the deposition of solid carbon as a function of the entering steam temperature and the steam to biomass molar ratio was developed. The model was successfully verified by experimental results. Based on the results of model, an optimal range of the steam to biomass molar ratio is recommended. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the feasibility study of a sound scientific, engineering, and technological solution for converting lignocellulosic biomass to electrical power using a trailer-scale downdraft biomass gasification system coupled with a spark-ignited IC engine/electric generator set for portable power applications on agricultural farms and in rural areas. The main objective of this study is to investigate the coupling and integration between the gasification unit and the power generation unit. Also it is intended to emphasize on the effectiveness of distributed power generation systems and demonstrate the feasibility of such integrated systems in real world scenarios, where the lignocellulosic biomass resources are widely available and distributed across the board. Four feedstock materials, pine, red oak, horse manure and cardboard that represent a wide spectrum of lignocellulosic biomass resources were chosen for the study. The efficiencies for individual components and the overall integrated system efficiencies were evaluated using experimental data and a thermal–chemical model for all four feedstocks. [Copyright &y& Elsevier]

The aviation sector has grown at a significant pace in recent years, and despite improvements in aircraft efficiency, the sector's impact on climate change is a growing concern. To address this concern, the International Civil Aviation Organization (ICAO) established the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) to help reduce aviation greenhouse gas (GHG) emissions. This paper presents a methodology agreed by the 193 ICAO member states to evaluate the life-cycle GHG emissions of sustainable aviation fuels (SAFs), in the CORSIA system. The core life-cycle assessment and induced land use change values of SAFs are presented to determine the GHG savings of certified pathways. The paper aims to present that a number of SAFs can yield significant life-cycle emission reductions compared to petroleum-derived jet fuel. This implies the potentially major role of SAFs in reducing aviation's carbon footprint. • The goal of the CORSIA is to reduce GHG emissions from international aviation. • Internationally agreed LCA methodologies for GHG saving potentials are presented. • Sustainable aviation fuels can reduce GHG emissions up to 90%. • SAFs GHG saving can exceed 100% when land use change is included. • Further challenges for reducing the GHG emissions from aviation are discussed. [ABSTRACT FROM AUTHOR]

Producing fuels and chemicals from waste is considered economically favorable, due to low feedstock cost, and environmentally favorable, due to avoided emissions from conventional waste management practices. In this study, we evaluate the life cycle greenhouse gas (GHG) emission reduction benefits of renewable natural gas (RNG) and lactic acid (LA) production from four types of wet waste feedstocks (wastewater sludge, food waste, swine manure, and fats, oil, and grease [FOG]) via anaerobic digestion (AD) and LA fermentation, respectively. RNG can be used as an alternative to fossil natural gas, while LA from waste feedstocks can displace conventional LA production pathways (mainly from corn via fermentation). Providing comprehensive life cycle GHG emissions of the combinations of waste feedstocks and products through different routes helps identify the GHG hotspots and show where emissions savings come from. The results show that the carbon intensities (CIs) of waste-derived RNG and LA are much lower than those of their counterparts. We estimated the life cycle GHG emissions for RNG to be between −146 and 27 g carbon dioxide equivalent (CO 2 e)/MJ, much lower than the CI of fossil fuels. Waste-derived LA pathways also show substantially lower CIs, ranging from −4.2 to −1.4 kgCO 2 e/kg LA, compared to the CIs of LA from corn and corn stover (1.2 and 0.3 kgCO 2 e/kg LA, respectively). We will also discuss that the low CIs of waste-derived products can come from low yields leading to high emission credits. Thus, life cycle analysis results presented per weight of treated waste can be used to support decisions about which waste feedstocks and products are to be used for sustainable waste valorization. In addition, we found that monetary emission reduction credits can play an important role in driving waste valorization. The Images of Waste, Trash Can, Flame, Beaker, and Sewer in the Graphical Abstract Are Public Domain, Courtesy of the Noun Project. [Display omitted] • Renewable natural gas and lactic acid can be produced from organic waste materials. • Conducted LCA to quantify the environmental benefits of waste-derived products. • Producing fuels/chemicals from waste can reduce GHG emissions. • Quantified potential economic benefits led by GHG emission reductions. • Economic benefits by GHG emission reductions can drive waste valorization. [ABSTRACT FROM AUTHOR]

Bioplastics recently have become an attractive, viable, and popular alternative to conventional petroleum-based plastics, with the hope that replacing fossil-derived plastics with renewable alternatives will reduce greenhouse gas (GHG) emissions and fossil energy consumption (FEC). The bioplastic industry is encouraging creative designs and enhanced properties such as biodegradability, which is considered a sustainable solution for waste plastic management. However, biodegradability also means that carbon in the product is emitted to the atmosphere as GHG emissions. In this paper, a life cycle analysis (LCA) of biodegradable polylactic acid (PLA) and bio-polyethylene (bio-PE) plastics was conducted to understand the environmental effects of these bioplastics from feedstock production to product end-of-life (EOL). In particular, emissions from biodegradability (EOL emissions) are accounted for. The results were compared to those of conventional fossil-based plastics such as high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Results showed that the lowest GHG emissions (−1.0 and 1.7 kg CO 2 e per kg for bio-PE and PLA with no biodegradation, respectively) and FEC (29 and 46 MJ per kg of bio-PE and PLA, respectively) were achieved with bio-derived plastics, particularly bio-PE plastic. However, despite the benefits of biogenic carbon uptake, when landfill and composting emissions were considered for the PLA pathway, the life cycle emissions of PLA increase significantly, from 16% to 163% depending on the biodegradation condition, compared to the case where there is no degradation in the landfill. This study also contributed to understand the effects on the GHG emissions of biodegradability in landfill and composting scenarios, regional electricity mix, and plastics manufacturing technologies. • Bioderived PE can offer lower GHG emissions and FEC than the fossil-based counterparts. • Biodegradability can greatly influence GHG emissions of bioplastics designed to degrade in landfills or composting. • Landfill and composting conditions of PLA determine biodegradability rates. • Renewable electricity will improve GHG emissions of PLA production. • Less energy-intensive processing methods will benefit the GHG emissions of the plastic pathways. [ABSTRACT FROM AUTHOR]

Most thermoelectric power plants in the United States (U.S.) rely on fresh water for cooling, resulting in significant water consumption. An understanding of the regional and seasonal water stress impact of such water consumption is needed. In this study, we used a U.S. county-level water stress index, Available Water Remaining for the United States (AWARE-US), with facility-level thermoelectric power generation water consumption data, to quantify the regional and seasonal water stress impact of U.S. thermoelectric power plants. Water stress impact was evaluated as water-scarcity footprint (WSF) using monthly AWARE-US data. Results show that most thermoelectric power plants in the United States that use fresh water are in water-abundant regions. Our findings also show that a small fraction of the U.S. thermoelectric generation facilities (13% by power) located in water stressed regions contribute the most water stress impact (88% of the total WSF) caused by thermoelectric power generation in the U.S. Even if fresh water is abundant on an annual basis, many power plants are in counties with seasonal water shortages. Of the 401 counties with thermoelectric power plants using fresh water for cooling, 80 counties in February and 160 counties in August had fresh water withdrawal requirements that exceeded the sustainable fresh water available (availability minus demand or AMD) in that region. This means that 27% and 46% of power generation facilities have difficulty securing sustainable fresh water in February and August, respectively. This study is intended to support water consumption management in existing power plants and guide the deployment of future power plants to mitigate water stress impact. • Regional/seasonal water stress impact of US thermoelectricity was evaluated. • Most thermal power plants in the US using fresh water are in water-abundant regions. • A few facilities in water-stressed regions contribute to most water stress impacts. • Plants can have seasonal water shortages even if water is abundant on an annual basis. [ABSTRACT FROM AUTHOR]

Advanced recycling enables the application of post-use plastics (PUP) to produce valuable industrial chemicals and develop markets for recycled feedstocks. Pyrolysis is one of the most common advanced recycling technologies undergoing industrial-scale implementation for converting PUP. This paper presents a life cycle analysis (LCA) to assess greenhouse gas (GHG) emissions, fossil energy, water consumption, and solid waste impacts of converting PUP into new plastics such as high-density and low-density polyethylene (HDPE and LDPE, respectively). Data was collected from eight plastic pyrolysis companies. This study addresses the impacts of pyrolysis plant size and maturity; two substitution rate (SR) cases of pyrolysis oil with fossil-derived feedstocks in steam crackers (5% and a 20% of pyrolysis oil SR); and potentially avoided emissions from traditional end-of-life (EOL) management. Because the conventional feedstock slate of steam crackers in the Unites States is comprised of 94% gases (a mix of ethane, propane, and butane) and 6% naphtha, the 5% SR case looked at polyethylene (PE) derived from 5% pyrolysis oil, 1% naphtha, and 94% gases; while the 20% SR looked at PE derived from 20% pyrolysis oil and 80% gases. Moreover, the results are presented from two perspectives: 1) steam crackers' and 2) plastic recyclers'. In the recyclers' perspective, the results for the 5% SR showed for each kg of PUP used there was a 23% and 18% decrease in GHG emissions for HDPE and LDPE respectively, while the 20% SR showed a 4% and 3% reduction in GHG emissions for HDPE and LDPE respectively compared to virgin plastic. The 20% SR has lower GHG emissions reductions because there is an added step of hydrotreating the pyrolysis oil to remove chlorine concentrations that is not included in the 5% SR scenario. Furthermore, the 5% SR removes most of the naphtha, a more carbon intense feedstock, and replaces it with PUP-based pyrolysis oil, a less carbon intense feedstock. GHG emissions for PUP pyrolysis could be further reduced by 50% and 131% in the United States and European Union respectively if the GHG emissions of current PUP incineration practices were considered as emission reductions credits. [Display omitted] • Plastic from pyrolysis N th -plants reduces impacts compared to virgin production. • Mass balance approach was used to develop results for two different perspectives. • Adding hydrotreatment to pyrolysis oil increase the carbon intensity. • Emissions reduction is sensitive to the conventional feedstock composition. • Counterfactual scenario results are sensitive to geographical location. [ABSTRACT FROM AUTHOR]

A mathematical model that describes a trailer scale biomass steam gasification system coupled with a solar collector heat source and a micro gas turbine is reported in this paper. This combined heat and power system is set to a prescribed output of 20 kW e and several system conditions have been optimized in a parametric study to minimize resource consumption rates. Biomass feeding rates under optimal conditions were found to range between 23 and 63 kg/h depending on the types of feedstock and other parameters. Water consumption is reduced through a condensation and recirculation process that is part of a heat recovery unit. Also, solar energy requirements have been reduced by means of a recuperator that extracts heat out of the combustion products. The overall system performance has been evaluated by a utilization factor which was found to range between 30% and 43%. The system has been compared to a baseline case of an air breathing gasification system of a similar scale. It was found that steam gasification produces the syngas with heating values over twice as high as those obtained by air gasification. Steam gasification also led to a 25% and 50% reduction in emission rates of contaminants like CO 2 and nitrogen oxides respectively relative to the baseline case. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) supply is an important consideration for algae production systems, and using high-purity CO 2 eliminates the need for purification processes. This study assessed the challenges and opportunities inherent in using waste high-purity CO 2 to produce algae in the United States. The United States' upper Midwest region is rich in high-purity CO 2 from corn ethanol production. However, its climate is not as favorable for algae production as that on the Gulf Coast. This study assessed the tradeoffs between these factors by comparing algae biofuel production with and without high-purity CO 2 across these two regions. Monthly algae cultivation was modeled in open ponds co-located with high-purity CO 2 sources in the Midwest and along the Gulf Coast, where many steam methane reforming and ammonia production facilities are located. This revealed that, by avoiding the energy-intensive carbon-capture process, an algae site that sources carbon from a high-purity CO 2 source would achieve a 9–39% reduction in life-cycle greenhouse gas (GHG) emissions and a 9–37% reduction in life-cycle fossil energy use compared to a similar site using dilute CO 2 for algae cultivation. The results also suggest that during warm months an algae pond in the Midwest would achieve results that are comparable to GHG emissions from a pond on the Gulf Coast. Furthermore, several Midwest algae ponds investigated in this study create less local water stress than those located along the Gulf Coast. The abundant high-purity CO 2 from corn ethanol plants thus creates a potential opportunity for algae cultivation in the Midwest. This study illustrated the interplay between algae productivity, CO 2 delivery, GHG emissions, and water stress in siting algae ponds. • Abundant high-purity CO 2 in the U.S. Midwest opens opportunities for algae growth. • The Interplay among CO 2 delivery, algal productivity, GHG, and water is considered. • Environmental benefits of using high-purity CO 2 for algae growth are evaluated. • The potential of utilizing high-purity CO 2 for algae growth in U.S is discussed. [ABSTRACT FROM AUTHOR]