(364v) Process Modeling and Techno-Economic Optimization for Producing Value-Added Products from Lignocellulosic Biomass

Research Interests: kinetic modeling, parameter estimation, techno economic optimization, Bayesian UQ, process systems engineering, sustainability

The gradual decline of fossil fuel reserves over the last few decades, coupled with an ever-increasing demand to reduce carbon footprint, has spurred a growing interest in exploring sustainable alternatives, the most common being lignocellulosic biomass. At present, biomass is being harnessed as a renewable resource of second-generation biofuels and chemicals – a greener alternative to traditional fossil fuel derivatives. My PhD research focuses on the effective and novel conversion processes for value-added products manufactured from biomass, such as monosaccharide platforms (C5 and C6 sugars) and lignin-soy protein isolate bio-adhesive.

In my work, the conventional kinetic models for biomass conversion reactions specifically, the depolymerization reactions have been improved by incorporating additional dependency terms accounting for the effect of catalyst concentrations on model yield, that sets it different from most state-of-the-art models. A detailed study on estimating the parameters of these kinetic models has been performed. The newly developed kinetic models and parameters has shown sufficient flexibility for predicting yields and performing simultaneous sensitivity analyses in a wide range of reaction conditions. For the technologies discussed in the later subsections, process models have been developed based on first-principles (FP) equations and those are validated against generated lab-scale data. Biomass conversion includes several reactions and different types of reactors have been designed by systematically addressing the challenges, leveraging available experimental data and software. In some cases, to enhance the overall productivity and sustainability of biomass conversion technologies effective separation methods have also been designed in the downstream of these reactors. Additionally, due to the lack of any commercial application of such processes, the development of rigorous techno-economic optimization approaches, along with scalability analyses and generation of economic measures (e.g., net present value, production revenue per annum etc.) have been conducted using the FP-based plant-wide models. Lignocellulosic biomass primarily comprises three polymeric components cellulose, hemicellulose, and lignin – however, their compositions vary significantly across plant species leading to potential inconsistencies in the outcomes of developed process models. Therefore, optimal operating conditions that maximize yields, are determined while considering the underlying uncertainty through the Bayesian Uncertainty Quantification (Bayesian UQ). It is crucial for ensuring adequate predictive accuracy and reliability of computational models used in lignocellulosic biomass conversion processes.

• Lignin-Soy Protein Isolate Bio-adhesive

Global wood-panel industry heavily depends on the formaldehyde-based adhesives (e.g., phenol-formaldehyde (PF), urea-formaldehyde (UF), etc.) that emit toxic volatile organic compounds (e.g., phenol, formaldehyde, etc.) and cause hazards to both human health and the environment. Soy protein crosslinked with kraft lignin partially degraded in presence of base catalyst, has enhanced adhesion properties. This lignin-soy protein bio-adhesive can be used as a potential formaldehyde-free substitute for adhesion industries. Given the variations in lignin compositions depending on their source, the Bayesian UQ approach has been employed in this process to improve the computational model yields.

• C5 C6 Sugar

Xylose (C5) and Glucose (C6) sugars are two of the most important platform intermedia generated through lignocellulose conversion. The polysaccharides (i.e., cellulose and hemicellulose) present in the lignocellulosic biomass can be depolymerized to produce C5 and C6 sugars through the concentrated acid-catalyzed hydrolysis (CAH) reaction preceded by a decrystallization process. A comprehensive techno-economic assessment including initial decrystallization followed by CAH has been conducted, which, to the best of our knowledge, has not been discussed in the existing literature.

Future Research Goals

Conversion of lignocellulosic biomass to value-added products contributes to renewable resource management, reduce dependence on finite fossil fuels and helps in mitigating climate changes as well. That is why, the research on process modeling and techno-economic optimization of various biomass conversion processes results in significant scientific and technological advancement towards sustainable development, energy security and economic growth. After completing my PhD, my research interests extend to various areas including multiscale modeling, clean energy technologies, renewables integration, life cycle assessment (LCA), hydrogen economy, carbon neutrality, and achieving net zero emissions. Drawing from my collaborative experiences with graduate students and post-doctoral scholars at WVU, I would also like to explore additional areas such as but not limited to , carbon capture-utilization-storage (CCUS), supply chain optimization, as well as machine learning applications. Through my PhD program, I have been fortunate to engage in a collaboration with USDA – National Institute of Food & Agricultural in the Mid-Atlantic Sustainable Biomass Consortium (MASBio) project. This collaboration has provided me with invaluable experience in working with external organizations, which I am certain will significantly benefit my future research endeavors. My current field of research and other areas mentioned above are actively pursued at present and have a high likelihood of receiving collaboration opportunities from agencies namely, NSF, EPA, USDA, DOE, and NETL among others.

References

1. Jiang, C. et al. Lignin oligomers from mild base-catalyzed depolymerization for potential application in aqueous soy adhesive as phenolic blends. Chem. Eng. 8, 2455–2465 (2023).
2. Zhou, Z., Liu, D. & Zhao, X. Conversion of lignocellulose to biofuels and chemicals via sugar platform: An updated review on chemistry and mechanisms of acid hydrolysis of lignocellulose. Renewable and Sustainable Energy Reviews 146 at https://doi.org/10.1016/j.rser.2021.111169 (2021).
3. Wolfaardt, F. J. et al. Recovery approaches for sulfuric acid from the concentrated acid hydrolysis of lignocellulosic feedstocks: A mini-review. Energy Convers. Manag. X 10, (2021).