scholarly journals Evaluating the Impacts of ACP Management on the Energy Performance of Hydrothermal Liquefaction via Nutrient Recovery

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 729 ◽  
Author(s):  
Sarah Bauer ◽  
Fangwei Cheng ◽  
Lisa Colosi
Keyword(s):  
Life Cycle ◽  
Energy Performance ◽  
Hydrothermal Liquefaction ◽  
Liquid Fuels ◽  
Precipitation Process ◽  
Net Energy ◽  
Modeling Framework ◽  
Energy Return On Investment ◽  
Theoretical Yield ◽  
Struvite Precipitation

Hydrothermal liquefaction (HTL) is of interest in producing liquid fuels from organic waste, but the process also creates appreciable quantities of aqueous co-product (ACP) containing high concentrations of regulated wastewater pollutants (e.g., organic carbon, nitrogen (N), and phosphorus (P)). Previous literature has not emphasized characterization, management, or possible valorization of ACP wastewaters. This study aims to evaluate one possible approach to ACP management via recovery of valuable scarce materials. Equilibrium modeling was performed to estimate theoretical yields of struvite (MgNH4PO4·6H2O) from ACP samples arising from HTL processing of selected waste feedstocks. Experimental analyses were conducted to evaluate the accuracy of theoretical yield estimates. Adjusted yields were then incorporated into a life-cycle energy modeling framework to compute energy return on investment (EROI) for the struvite precipitation process as part of the overall HTL life-cycle. Observed struvite yields and residual P concentrations were consistent with theoretical modeling results; however, residual N concentrations were lower than model estimates because of the volatilization of ammonia gas. EROI calculations reveal that struvite recovery is a net-energy producing process, but that this benefit offers little to no improvement in EROI performance for the overall HTL life-cycle. In contrast, corresponding economic analysis suggests that struvite precipitation may be economically appealing.

Algaculture as a Feedstock Source for Biodiesel Fuel: A Life Cycle Analysis

2009 ◽  
Author(s):  
Peter S. Curtiss ◽  
Jan F. Kreider
Keyword(s):  
Life Cycle ◽  
Life Cycle Analysis ◽  
Economic Security ◽  
Liquid Fuels ◽  
Biodiesel Fuel ◽  
Energy Return On Investment ◽  
Light Vehicle ◽  
Alternative Sources ◽  
Biodiesel Fuels ◽  
Land Water

This research investigates algae as a feedstock for producing liquid fuels for the light vehicle sector. It is in the interest of national economic security to investigate alternative sources of transportation energy before the extraction of existing supplies becomes prohibitively expensive. Biofuels are one such alternative liquid fuel supply. The research used the Life Cycle Analysis (LCA) approach for evaluating the production of biodiesel fuel from algae as a feedstock, including processes for growing algae in conventional and accelerated processes in bioreactors. An energy return on investment and comparison with conventional fuels (gasoline, diesel fuel) on an LCA basis and on a resource consumption basis (e.g., land, water, feedstock) is also presented. The results are reported for required land use, water use, input-to-output energy ratio, and carbon emissions for algacultural biodiesel fuel. From the present study it appears that algae-derived biodiesel fuel requires significantly less land, water and energy than do all other biodiesel fuels. It would appear prudent for the US to vigorously pursue this option since a significant fraction of US light vehicle fuel needs can be addressed.

scholarly journals Morphogenesis and evolution mechanisms of bacterially-induced struvite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tian-Lei Zhao ◽  
Han Li ◽  
Hao-Fan Jiang ◽  
Qi-Zhi Yao ◽  
Ying Huang ◽  
...  
Keyword(s):  
Time Course ◽  
Carboxyl Groups ◽  
Precipitation Process ◽  
Phosphate Content ◽  
Biomimetic Mineralization ◽  
Struvite Precipitation ◽  
Growth Habits ◽  
Two Stages ◽  
Relevant Work ◽  
Insight Into

AbstractBacteria are able to induce struvite precipitation, and modify struvite morphology, leading to the mineral with various growth habits. However, the relevant work involving the morphogenesis is limited, thereby obstructing our understanding of bacterially mediated struvite mineralization. Here, an actinomycete Microbacterium marinum sp. nov. H207 was chosen to study its effect on struvite morphology. A combination of bacterial mineralization and biomimetic mineralization techniques was adopted. The bacterial mineralization results showed that strain H207 could induce the formation of struvite with grouping structure (i.e., a small coffin-like crystal grown on a large trapezoid-like substrate crystal), and the overgrowth structure gradually disappeared, while the substrate crystal further evolved into coffin-like, and quadrangular tabular morphology with time. The biomimetic experiments with different organic components confirmed that the soluble macromolecules rich in electronegative carboxyl groups secreted by strain H207 dominate the formation of the struvite grouping. The time-course biomimetic experiments with supernatant testified that the increase in pH and NH4+ content promoted the evolution of crystal habits. Moreover, the evolution process of substrate crystal can be divided into two stages. At the first stage, the crystal grew along the crystallographic b axis. At the later stage, coupled dissolution–precipitation process occurred, and the crystals grew along the corners (i.e., [110] and [1-10] directions). In the case of dissolution, it was also found that the (00-1) face of substrate crystal preferentially dissolved, which results from the low initial phosphate content and high PO43− density on this face. As a result, present work can provide a deeper insight into bio-struvite mineralization.

scholarly journals Life Cycle GHG Emissions of Residential Buildings in Humid Subtropical and Tropical Climates: Systematic Review and Analysis

Buildings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 6
Author(s):  
Daniel Satola ◽  
Martin Röck ◽  
Aoife Houlihan-Wiberg ◽  
Arild Gustavsen
Keyword(s):  
Systematic Review ◽  
Life Cycle ◽  
Residential Buildings ◽  
Construction Materials ◽  
Ghg Emissions ◽  
Energy Performance ◽  
Cycle Performance ◽  
Tropical Climates ◽  
Building Life Cycle ◽  
Total Life

Improving the environmental life cycle performance of buildings by focusing on the reduction of greenhouse gas (GHG) emissions along the building life cycle is considered a crucial step in achieving global climate targets. This paper provides a systematic review and analysis of 75 residential case studies in humid subtropical and tropical climates. The study investigates GHG emissions across the building life cycle, i.e., it analyses both embodied and operational GHG emissions. Furthermore, the influence of various parameters, such as building location, typology, construction materials and energy performance, as well as methodological aspects are investigated. Through comparative analysis, the study identifies promising design strategies for reducing life cycle-related GHG emissions of buildings operating in subtropical and tropical climate zones. The results show that life cycle GHG emissions in the analysed studies are mostly dominated by operational emissions and are the highest for energy-intensive multi-family buildings. Buildings following low or net-zero energy performance targets show potential reductions of 50–80% for total life cycle GHG emissions, compared to buildings with conventional energy performance. Implementation of on-site photovoltaic (PV) systems provides the highest reduction potential for both operational and total life cycle GHG emissions, with potential reductions of 92% to 100% and 48% to 66%, respectively. Strategies related to increased use of timber and other bio-based materials present the highest potential for reduction of embodied GHG emissions, with reductions of 9% to 73%.

scholarly journals Conversion of biomass to biofuels and life cycle assessment: a review

2021 ◽  
Author(s):  
Ahmed I. Osman ◽  
Neha Mehta ◽  
Ahmed M. Elgarahy ◽  
Amer Al-Hinai ◽  
Ala’a H. Al-Muhtaseb ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Biomass Conversion ◽  
Biofuel Production ◽  
Process Efficiency ◽  
Liquid Fuels ◽  
Thermochemical Processes ◽  
Lower Temperature

AbstractThe global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.

scholarly journals Strategies to Improve the Energy Performance of Buildings: A Review of Their Life Cycle Impact

Buildings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 105 ◽  
Author(s):  
Nadia MIRABELLA ◽  
Martin RÖCK ◽  
Marcella Ruschi Mendes SAADE ◽  
Carolin SPIRINCKX ◽  
Marc BOSMANS ◽  
...  
Keyword(s):  
Life Cycle ◽  
Case Studies ◽  
Environmental Impacts ◽  
Energy Use ◽  
Ghg Emissions ◽  
Energy Performance ◽  
Environmental Benefits ◽  
Embodied Energy ◽  
Trade Offs ◽  
Operational Energy

Globally, the building sector is responsible for more than 40% of energy use and it contributes approximately 30% of the global Greenhouse Gas (GHG) emissions. This high contribution stimulates research and policies to reduce the operational energy use and related GHG emissions of buildings. However, the environmental impacts of buildings can extend wide beyond the operational phase, and the portion of impacts related to the embodied energy of the building becomes relatively more important in low energy buildings. Therefore, the goal of the research is gaining insights into the environmental impacts of various building strategies for energy efficiency requirements compared to the life cycle environmental impacts of the whole building. The goal is to detect and investigate existing trade-offs in current approaches and solutions proposed by the research community. A literature review is driven by six fundamental and specific research questions (RQs), and performed based on two main tasks: (i) selection of literature studies, and (ii) critical analysis of the selected studies in line with the RQs. A final sample of 59 papers and 178 case studies has been collected, and key criteria are systematically analysed in a matrix. The study reveals that the high heterogeneity of the case studies makes it difficult to compare these in a straightforward way, but it allows to provide an overview of current methodological challenges and research gaps. Furthermore, the most complete studies provide valuable insights in the environmental benefits of the identified energy performance strategies over the building life cycle, but also shows the risk of burden shifting if only operational energy use is focused on, or when a limited number of environmental impact categories are assessed.

scholarly journals A Comparison of Life Cycle Energy and Carbon Impacts for Passive Detached Accessory Dwelling Units and Their Design Implications

2021 ◽  
Author(s):  
Deva Siva Veylan
Keyword(s):  
Life Cycle ◽  
Energy Use ◽  
Performance Metrics ◽  
Ghg Emissions ◽  
Energy Performance ◽  
Design Standards ◽  
Passive House ◽  
Accessory Dwelling Units ◽  
Passive Design ◽  
House Size

Detached accessory dwelling units are a building typology that, when built to passive design standards, can help reduce GHG emissions while addressing the socioeconomic pressures facing many housing markets. Energy performance metrics like those used in passive design standards are based on per unit of floor area and lead to a size-bias against smaller housing typologies. A life cycle assessment of cost-optimal passive house sizes ranging from 230 m² (2,500 ft²) to 30 m² (300 ft²) is performed to understand their total life cycle energy use and GHG emissions implications. Additionally, an analysis using BEopt examines operational energy use for 10 cost-optimal passive house sizes ranging from 230 m² (2,500 ft²) to 30 m² (300 ft²) across all 17 climate zones and examines how cost-optimal passive design changes with house size. The results show that per-occupant energy use and GHG emissions are similar or better for small house sizes and that cost-optimal passive design does not change significantly with house size.

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