(206a) Plant-Wide Modeling and Techno-Economic Analysis of Microwave-Assisted Gasification Process for H2 Generation Using a Mixed Feedstock of Biomass and Plastics

Projected future consumption of H₂ is anticipated to reach 2.3 Gt/yr across industries including synthetic chemistry, transportation, heating, and power generation [1]. Hydrogen holds the potential to decarbonize approximately 18% of energy-related sectors and playing a crucial role in transitioning towards a fully renewable energy society [2]. Currently, over 98% of H₂ is derived from fossil fuels, predominantly through processes like steam reforming (76%), and coal gasification (22%) [3]. To mitigate rising energy demands, environmental concerns, depletion of resources, and volatile fossil fuel prices have spurred interest in producing H₂ from sustainable energy sources such as biomass, waste plastics, and municipal solid waste. To generate H₂ from solid feedstock (biomass and mixed plastics), gasification, a thermochemical conversion process, is a preferred method. However, gasification process is energy intensive, requires high temperature up to 1100ËšC, making the process infeasible. In recent times, there has been growing interest in microwave assisted heating process within chemical reaction systems due to their low energy requirements compared to conventional methods [4]. As microwave directly interacts with the material, temperature increases rapidly due to selective heating, enhancing overall energy efficiency and reducing operational costs. Furthermore, nonthermal effect of microwave helps to limit the side reactions and can improve the yield of desired products. This study focuses on developing a plant-wide model for producing H₂ from a mixed feedstock of biomass and mixed plastics. Initially, a lab-scale air-assisted microwave gasifier model is developed by applying data reconciliation technique to minimize errors with experimental results. This lab-scale model is then scaled up to a commercial level and integrated into the plant-wide model. The plant wide model consists of several sections including gasification, gas cleaning, cooling, scrubbing, compression, sulfur removal, steam reforming, shift conversion, and H₂ purification using pressure swing adsorption (PSA) [5]. Economic analysis of the plant-wide model shows a reduction in capital expenditure (CAPEX) and operating expenditure (OPEX) by 10% - 15%, specifically 35% reduction in energy requirements and a 20% improvement in net present value (NPV) compared to conventional process. Sensitivity studies are performed for variation in feed mix and its composition.

References:

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