Data-driven optimization of biomass conversion pathways: integrating thermochemical processes

Environmental life cycle assessment of biomass conversion using hydrothermal technology: A review

Techno-economic and life cycle analysis of biofuel production via hydrothermal liquefaction of microalgae in a methanol-water system and catalytic hydrotreatment using hydrochar as a catalyst support

Microwave-assisted pyrolysis in biomass and waste valorisation: Insights into the life-cycle assessment (LCA) and techno-economic analysis (TEA)

A promising route to transition wastewater treatment facilities (WWTFs) from energy-consuming to net energy-positive is to retrofit existing facilities with process modifications, residual biosolid upcycling, and effluent thermal energy recovery. This study assesses the economics and life cycle environmental impacts of three proposed retrofits of WWTFs that consider thermochemical conversion technologies, namely, hydrothermal liquefaction, slow pyrolysis, and fast pyrolysis, along with advanced bioreactors. The results are in turn compared to the reference design, showing the retrofitting design with hydrothermal liquefaction, and an up-flow anaerobic sludge blanket has the highest net present value (NPV) of $177.36MM over a 20-year plant lifetime despite 15% higher annual production costs than the reference design. According to the ReCiPe method, chlorination is identified as the major contributor for most impact categories in all cases. There are several uncertainties embedded in the techno-economic analysis and life cycle assessment, including the discount rate, capital investment, sewer rate, and prices of main products; among which, the price of biochar presents the widest variation from $50 to $1900/t. Sensitivity analyses reveal that the variation of discount rates causes the most significant changes in NPVs. The impact of the biochar price is more pronounced in the slow pyrolysis-based pathway compared to the fast pyrolysis since biochar is the main product of slow pyrolysis.

Life Cycle Assessment (LCA) has been introduced to Thai industries in 1997 as one of the ISO 14000 series. The concept of LCA is being gradually accepted. However, there are few formal LCA studies in Thailand so far due to a limited number of LCA experts and a lack of sufficient databases relevant to domestic conditions. The LCA activities in Thailand can be divided into 3 areas, which are (1) Workshops and seminars (2) Use of LCA studies in Ecolabelling and (3) Life Cycle Inventory (LCI) and LCA studies. The first LCI study was to develop LCI data for Thailand Electricity Grid Mixes. There are a few LCA thesis studies in some universities, but these studies used databases from commercial software programs. The study and use of LCA may increase in the future only if domestic background database will be provided by research institutes and the government, and if industry understands LCA methodology through periodical workshops and seminars. INTRODUCTION Life Cycle Assessment has been introduced to Thai industries in 1997 as one of the ISO 14000 series. The concept of LCA is being gradually accepted. However, there are few formal LCA studies in Thailand so far due to a limited number of LCA experts and a lack of sufficient databases relevant to domestic conditions. ACTIVITIES The LCA activities in Thailand can be divided into 3 areas including (1) Workshops and seminars (2) Use of LCA studies in Ecolabelling and (3) Life Cycle Inventory (LCI) and LCA studies. 1. Workshop and Seminar To introduce the LCA concept to Thai Industries, the Thailand Environment Institute (TEI), in cooperation with many organizations, organized LCA seminars/workshops in Thailand annually between 1997-2002. All seminars successfully gained attention from Thai industry and educational institutes. The Thailand LCA Forum (http://doi.eng.cmu.ac.th/Thailca) has been launched by TEI in January of 2002. 2. Use of LCA studies in Ecolabelling The Green Label project was initiated in October 1993 by the Thailand Business Council for Sustainable Development (TBCSD) in association with the Ministry of Industry. This project is supported by the Secretariat, which is formed by a partnership between the Thai Industrial Standards Institute (TISI) and TEI. The objectives of the project are to establish the product criteria and award certification to specific products that are shown to have less impact on the environment, when compared with other products serving the same function (not including foods, drinks, and pharmaceuticals). The project came about from the idea that the green label can stimulate market choice thus encouraging producers to improve the environmental quality of their products and services in response to consumer demand. Award of the Thai Green label is based on the product criteria developed by a technical subcommittee. The subcommittee consists of representatives from the scientific, business and environmental groups and others if appropriate and available. A new subcommittee is established for each selected product category. At present, there are 29 product categories that are eligible for the Thai Green Label, and up to the end of November 2001, 227 individual products have received the Green Label award. Being aware of the high cost involved and time consumed in developing product criteria through format LCA, the Thai Green Label scheme has decided that a full quantitative LCA is not applicable for setting criteria for all products, especially in developing countries. The development of award criteria for the scheme has followed different methodologies. It will take into account not only significant environmental impact during the life cycle of the products (Life Cycle Consideration: LCC), but also capability to meet proposed criteria with reasonable process modification and/or improvement. The availability of testing institutes and the ability to perform tests are considered carefully, while setting the criteria. Results from existing LCA studies have been used as a scientific tool in the Thai Green Label Scheme for the development of environmental criteria for a few product categories. 3. Life Cycle Inventory (LCI) and LCA Studies

Hydrothermal liquefaction of biomass for bio-crude production: A review on feedstocks, chemical compositions, operating parameters, reaction kinetics, techno-economic study, and life cycle assessment

The pursuit of sustainable energy production through the conversion of agricultural waste into different bioenergy resources is of paramount importance given its potential to mitigate environmental impact while meeting energy demands. In this review, a comprehensive overview of the technologies for the biochemical and thermochemical conversion of agricultural waste into bioenergy is provided. A summary of the process of its conversion into different bioenergy products such as biogas, bio-oil, and biofuel is provided, in addition to the potential advantages and challenges faced using different biomass conversion technologies. The review highlights the potential of agricultural waste valorization to address the current energy demand while at the same time contributing to environmental benefits and greenhouse gas emission reductions. Moreover, this review highlights some significant gaps for improvement. These include the challenges in the pretreatment of agricultural waste biomass in optimizing the conversion rates and lowering the required energy consumption throughout the process while enhancing both the quantity and quality of the output. Some recommendations are proposed to address the identified challenges. These include the need for further studies for a thorough assessment to evaluate the efficacity and sustainability of agricultural waste valorization technologies. Assessment methods such as life cycle assessment (LCA), life cycle analysis (LCA), net energy ratio (NER) calculations, life cycle costing (LCC), as well as techno-economic assessment (TEA), are recommended, together with collaboration among governments, farmers, and researchers, as well as the integration of cutting-edge technologies to enhance various aspects of agricultural waste, optimizing the conversion process, cost efficiency, time management, and labor requirements, consequently boosting the conversion efficiency and product quality.

Integration of techno-economic analysis and life cycle assessment for sustainable process design – A review

Circular utilization of urban tree waste contributes to the mitigation of climate change and eutrophication

Life cycle assessment of bio-jet fuel from hydrothermal liquefaction of microalgae

Feeding a growing, increasingly affluent population while limiting environmental pressures of food production is a central challenge for society. Understanding the location and magnitude of food production is key to addressing this challenge because pressures vary substantially across food production types. Applying data and models from life cycle assessment with the methodologies for mapping cumulative environmental impacts of human activities (hereafter cumulative impact mapping) provides a powerful approach to spatially map the cumulative environmental pressure of food production in a way that is consistent and comprehensive across food types. However, these methodologies have yet to be combined. By synthesizing life cycle assessment and cumulative impact mapping methodologies, we provide guidance for comprehensively and cumulatively mapping the environmental pressures (e.g., greenhouse gas emissions, spatial occupancy, and freshwater use) associated with food production systems. This spatial approach enables quantification of current and potential future environmental pressures, which is needed for decision makers to create more sustainable food policies and practices.

PurposeLife cycle thinking (LCT) and life cycle assessment (LCA) are increasingly considered pivotal concept and method for supporting sustainable transitions. LCA plays a relevant role in decision support, for the ambition of a holistic coverage of environmental dimensions and for the identification of hotspots, possible trade-offs, and burden shifting among life cycle stages or impact categories. These features are also relevant when the decision support is needed in policy domain. With a focus on EU policies, the present study explores the evolution and implementation of life cycle concepts and approaches over three decades.MethodsAdopting an historical perspective, a review of current European Union (EU) legal acts and communications explicitly mentioning LCT, LCA, life cycle costing (LCC), and environmental footprint (the European Product and Organisation Environmental Footprint PEF/OEF) is performed, considering the timeframe from 1990 to 2020. The documents are categorised by year and according to their types (e.g. regulations, directives, communications) and based on the covered sectors (e.g. waste, energy, buildings). Documents for which life cycle concepts and approaches had a crucial role are identified, and a shortlist of these legal acts and communications is derived.Results and discussionOver the years, LCT and life cycle approaches have been increasingly mentioned in policy. From the Ecolabel Regulation of 1992, to the Green Deal in 2019, life cycle considerations are of particular interest in the EU. The present work analysed a total of 159 policies and 167 communications. While in some sectors (e.g. products, vehicles, and waste) life cycle concepts and approaches have been adopted with higher levels of prescriptiveness, implementation in other sectors (e.g. food and agriculture) is only at a preliminary stage. Moreover, life cycle (especially LCT) is frequently addressed and cited only as a general concept and in a rather generic manner. Additionally, more stringent and rigorous methods (LCA, PEF/OEF) are commonly cited only in view of future policy developments, even if a more mature interest in lifecycle is evident in recent policies.ConclusionThe EU has been a frontrunner in the implementation of LCT/LCA in policies. However, despite a growing trend in this implementation, the development of new stringent and mandatory requirements related to life cycle is still relatively limited. In fact, there are still issues to be solved in the interface between science and policy making (such as verification and market surveillance) to ensure a wider implementation of LCT and LCA.

The body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statisticalmore » sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.« less

Biomass conversion technologies employ many diverse research and development activities involved in the basic techniques focused on the breakdown and conversion of the biomass. The development and design of disruptive biomass conversion processes is a crucial concern as the environmental and economic sustainability for this process after scale-up is not usually ensured. Technology readiness levels (TRLs) at the early stages are usually used by researchers to follow the stages of research, development, and deployment (RD&D) activities. These, however, lack detailed analysis of the feasibility of project success and sometimes lead to information that triggers expensive decisions. Hence, as a practice, techno-economic analysis (TEA) and life-cycle analysis (LCA) of novel processes and technologies are essential to ensure sustainable decisions across the phases of a project and to prevent unnecessary expenditure losses. In this chapter, we highlight the importance of performing TEA and LCA and review key developments. TEAs offer useful technical and financial data for addressing project bottlenecks and enhancing scale-up possibilities. The LCA studies have mostly been done using the cradle-to-gate system scope and have focused on quantifying climate change impacts. Most results have reported reduction in climate change impact as compared to fossil fuels. However, indirect land use change has been identified as a controversial aspect, requiring attention. Water requirement has also been reported to be high, typically more than 250 l/l of ethanol. Finally, the limited data availability, particularly for developing countries such as India, needs to be addressed to improve the reliability.

Algae, a renewable energy source, has an added advantage of consuming nutrients from wastewater and consequently aiding in wastewater treatment. The algae thus produced can be processed using alternative paths for conversion to fuels. However, due to high moisture content of algae, wet algae processing methods are being encouraged to avoid the dewatering cost and energy. Hydrothermal liquefaction is one such technology that converts the algae into high heating value bio-oil under high temperature and pressure. This bio-oil can be further upgraded to renewable diesel (RD) which can be used in diesel powered vehicles without any modifications. The objective of this study is to evaluate the economic viability and to estimate the energy use and greenhouse gas (GHG) emissions during life cycle of RD production from algae grown in wastewater using hydrothermal liquefaction. Economic analysis of RD production on commercial scale was performed using engineering process model of RD production plant with processing capacity of 60 Mgal wastewater/day, simulated in SuperPro designer. RD yields for algae were estimated as 10.18 MML/year with unit price of production as $1.75/RD. The GHG emissions during life cycle of RD production were found to be 6.2 times less than those produced for conventional diesel. Sensitivity analysis indicated a potential to reduce ethanol production cost either by using high lipid algae or increasing the plant size. The integrated economic and ecological assessment analyses are helpful in determining long-term sustainability of a product and can be used to drive energy policies in an environmentally sustainable direction.