An official website of the United States government
Alternative polymer feedstocks are highly desirable to address environmental, social, and security concerns associated with petrochemical-based materials. Lignocellulosic biomass (LCB) has emerged as one critical feedstock in this regard because it is an abundant and ubiquitous renewable resource. LCB can be deconstructed to generate valuable fuels, chemicals, and small molecules/oligomers that are amenable to modification and polymerization. However, the diversity of LCB complicates the evaluation of biorefinery concepts in areas including process scale-up, production outputs, plant economics, and life-cycle management. We discuss aspects of current LCB biorefinery research with a focus on the major process stages, including feedstock selection, fractionation/deconstruction, and characterization, along with product purification, functionalization, and polymerization to manufacture valuable macromolecular materials. We highlight opportunities to valorize underutilized and complex feedstocks, leverage advanced characterization techniques to predict and manage biorefinery outputs, and increase the fraction of biomass converted into valuable products.
more »
« less
Engineering Innovations, Challenges, and Opportunities for Lignocellulosic Biorefineries: Leveraging Biobased Polymer Production
Alternative polymer feedstocks are highly desirable to address environmental, social, and security concerns associated with petrochemical-based materials. Lignocellulosic biomass (LCB) has emerged as one critical feedstock in this regard because it is an abundant and ubiquitous renewable resource. LCB can be deconstructed to generate valuable fuels, chemicals, and small molecules/oligomers that are amenable to modification and polymerization. However, the diversity of LCB complicates the evaluation of biorefinery concepts in areas including process scale-up, production outputs, plant economics, and life-cycle management. We discuss aspects of current LCB biorefinery research with a focus on the major process stages, including feedstock selection, fractionation/deconstruction, and characterization, along with product purification, functionalization, and polymerization to manufacture valuable macromolecular materials. We highlight opportunities to valorize underutilized and complex feedstocks, leverage advanced characterization techniques to predict and manage biorefinery outputs, and increase the fraction of biomass converted into valuable products.
more »
« less
- Award ID(s):
- 1934887
- PAR ID:
- 10448725
- Date Published:
- Journal Name:
- Annual review of chemical and biomolecular engineering
- Volume:
- 14
- ISSN:
- 1947-5446
- Page Range / eLocation ID:
- 109-40
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract This study performs techno‐economic analysis and Monte Carlo simulations (MCS) to explore the effects that variations in biomass feedstock quality have on the economic feasibility of fast pyrolysis biorefineries using decentralized preprocessing sites (i.e., depots that produce pellets). Two biomass resources in the Southeastern United States, that is, pine residues and switchgrass, were examined as feedstocks. A scenario analysis was conducted for an array of different combinations, including different pellet ash control levels, feedstock blending ratios, different biorefinery capacities, and different biorefinery on‐stream capacities, followed by a comparison with the traditional centralized system. MCS results show that, with depot preprocessing, variations in the feedstock moisture and feedstock ash content can be significantly reduced compared with a traditional centralized system. For a biorefinery operating at 100% of its designed capacity, the minimum fuel selling price (MFSP) of the decentralized system is $3.97–$4.39 per gallon gasoline equivalent (GGE) based on the mean value across all scenarios, whereas the mean MFSP for the traditional centralized system was $3.79–$4.12/GGE. To understand the potential benefits of highly flowable pellets in decreasing biorefinery downtime due to feedstock handling and plugging problems, this study also compares the MFSP of the decentralized system at 90% of its designed capacity with a traditional system at 80%. The analysis illustrates that using low ash pellets mixed with switchgrass and pine residues generates a more competitive MFSP. Specifically, for a biorefinery designed for 2,000 oven dry metric ton per day, running a blended pellet made from 75% switchgrass and 25% pine residues with 2% ash level, and operating at 90% of designed capacity could make an MFSP between $4.49 and $4.71/GGE. In contrast, a traditional centralized biorefinery operating at 80% of designed capacity marks an MFSP between $4.72 and $5.28.more » « less
-
Many recent efforts towards sustainable polymer development use building blocks from renewable biomass feedstocks. However, issues arising from the processes used to extract starting materials from biomass are often overlooked despite the safety and environmental hazards associated with energy-intensive separation processes and solvent utilization. Here, we describe a holistic approach towards using green solvents and processes to synthesize polyester thermosets from birch bark, a waste product from the paper and pulp industry. Betulin, a diol with a pentacyclic ring structure, was extracted from the bark of silver birch trees via reflux boiling using green solvents available from biobased sources. Ethanol and 1:1 ethanol:ethyl acetate mixtures were effective solvents for extraction with additional selectivity achieved via antisolvent precipitation. Betulin-rich extracts containing 62.2-81.5 wt% betulin were produced and directly used to prepare polyester thermosets using one-pot, solventless polycondensations with 100% of the starting materials available from biomass feedstocks. The polymers prepared directly from extracts had comparable properties to those synthesized from pure betulin, suggesting that additional processing steps required to achieve higher purity betulin may not be warranted. Overall, we present an approach to polyester development from betulin-rich birch bark extracts which incorporate green chemistry and engineering principles from feedstock to product.more » « less
-
Thermal insulation materials reduce heat transfer and are typically made from materials like fiberglass, foam, or mineral wool, which are engineered to trap air and hinder heat conduction and convection. The traditional manufacturing processes of thermal insulation materials are often energy-intensive and result in significant greenhouse gas emissions. In the current global drive for sustainability, these energy-intensive manufacturing processes raise environmental concerns and need to be addressed. In this work, with the objective of addressing both material sustainability and manufacturing sustainability, we present an additive manufacturing strategy to fabricate biomass materials for thermal insulation applications. Firstly, we propose to use biomass materials, such as wheat straw, as the primary feedstock materials for manufacturing. Such biomass materials offer the unique capacity to sequester carbon dioxide during their growth, and when incorporated into thermal insulation structures, they effectively capture and store carbon inside the structure. Concurrently, our pursuit of manufacturing process sustainability is driven by using a cost-effective additive manufacturing technology to fabricate durable thermal insulation structures. In the presented work, we first demonstrate the formulation of a 3D-printable ink using chopped straw fibers. We conduct comprehensive rheological characterizations to reveal the shear-thinning properties and the printability of the straw fiber ink. Utilizing the direct ink writing (DIW) process, the straw fiber material is deposited into 3D structures. Following bulk material characterization tests, including microstructure, mechanical, and thermal tests. We unveil the low thermal conductivity and robust mechanical properties. This paper marks the first work of 3D printing of wheat straw fibers for thermal insulation structures. The discoveries in this pilot work demonstrate the potential to leverage additive manufacturing technologies and sustainable biomass materials to create both functional and value-added wheat straw parts tailored for thermal insulation applications.more » « less
-
null (Ed.)3D printing is an essential tool for rapid prototyping in a variety of sectors such as automotive and public health. The 3D printing market is booming, and it is projected that it will continue to thrive in the coming years. Unfortunately, this rapid growth has led to an alarming increase in the amount of 3D printed plastic waste. 3D printing processes such as stereolithography (SLA) and digital light projection (DLP) in particular generally produce petroleum-based thermosets that are further worsening the plastic pollution problem. To mitigate this 3D printed plastic waste, sustainable alternatives to current 3D printing materials must be developed. The present review provides a comprehensive overview of the sustainable advances in SLA/DLP 3D printing to date and offers a perspective on future directions to improve sustainability in this field. The entire life cycle of 3D printed parts has been assessed by considering the feedstock selection and the end-of-use of the material. The feedstock selection section details how renewable feedstocks (from lignocellulosic biomass, oils, and animal products) or waste feedstocks ( e.g. , waste cooking oil) have been used to develop SLA/DLP resins. The end-of-use section describes how materials can be reprocessed ( e.g. thermoplastic materials or covalent adaptable networks) or degraded (through enzymatic or acid/base hydrolysis of sensitive linkages) after end-of-use. In addition, studies that have employed green chemistry principles in their resin synthesis and/or have shown their sustainable 3D printed parts to have mechanical properties comparable to commercial materials have been highlighted. This review also investigates how aspects of sustainability such as recycling for feedstock/end-of-use or biodegradation of 3D printed parts in natural environments can be incorporated as future research directions in SLA/DLP.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
