Showing papers by "Sudip Kumar Rakshit published in 2021"

A Techno-economic Analysis for Integrating an Electrochemical Reactor into a Lignocellulosic Biorefinery for Production of Industrial Chemicals and Hydrogen

Abstract: In this study, we present a techno-economic analysis for integrating an electrochemical reactor into a lignocellulosic biorefinery for the purpose of converting biorefinery lignin to higher-value industrial chemicals with co-generation of hydrogen. We consider how the electrochemical reactor impacts the manufacturing costs for producing biofuel and determine a break-even value for the lignin oxidation product stream, which is the minimum lignin conversion product stream value that renders the cost to produce biofuel the same as in the typical biorefinery concept. We conclude that at low extents of lignin conversion, the break-even product stream value is likely too high for the process to be feasible. However, at higher extents of lignin conversion, the break-even product stream value may be between $1.00 and $2.00/kg, depending on capital cost and other manufacturing costs like depreciation. Potential markets for the biomass conversion products include resin manufacturing, where the products would compete with petroleum-derived resin precursors.

Plastics: Toward a Circular Bioeconomy

Abstract: Plastics are synthetic polymers that are lightweight and exhibit a high tensile strength, durability, and chemical inertness, leading to a host of applications. However, these same properties make their degradation difficult and have resulted in significant accumulation in the environment. Plastic characteristics include hydrophobicity, degree of crystallinity, molecular size of the constituent polymer, etc. Each character plays a crucial role in plastic biodegradability. The low degradation rates and the subsequent effect on ecology is a major environmental concern. Considerable ongoing research is focusing on the biodegradation of plastics and bioplastics by various microorganisms and their constituent enzymes. These biocatalysts are specific to the constituent functional groups, degree of polymerization, etc. The breakdown rates and composition of the final products depend on several factors including physical and chemical pretreatments. Unlike recycling and composting, these studies aim to break down the plastics to monomeric or short-chain polymers that can be reused. The obtention of reusable “end-of-life” monomers or oligomers and re-introduction into the production cycle will help to complete the loop and the use of plastics from a linear to a circular bioeconomy. Such processes will reduce the original resource input with each complete cycle making the process much more sustainable. With this knowledge, the development of new plastics will move toward the products that can be broken down into reusable compounds after its end-use. This chapter will review the degradability potential of plastics and bioplastics to reusable materials that can be adapted by the plastic industry for a cascading circular bioeconomy.