Carbon Dioxide Conversion and Utilization

Development and Characterization of Densified Biomass-plastic Blend for Entrained Flow Gasification

The main objective of the proposed work is to utilize the existing thermogravimetric analysis (TGA)-mass spectrometer (MS), 1.5” drop tube furnace, 1 ton per day (TPD) coal gasifier and high pressure extruder to develop and study a coal/biomass/plastic fuel with a surface area less than 10 m²/m³ that is suitable for oxygen-blown entrained flow gasification with slurry feed. Conventional biomass pretreatment has been limited in application to fluidized-type or moving bed-type gasifiers due to the high-water uptake by porous biomass containing hydroxyl groups during the conventional slurry preparation resulting in a highly viscous, unpumpable slurry. To address this issue, biomass will be processed with coal and plastic for densification and to remove or encapsulate the hydroxyl groups at the lab-scale using either a hydraulic press or by extrusion co-processing. Upon a preferable production process and operating parameters being identified, approximately 600 kg pine wood-plastic fuel will be prepared for lab-scale studies with/out coal on grindability; slurryability and stability while considering different gasification kinetics between plastic/biomass and coal. Lastly, testing will be conducted with an acceptable coal/biomass/plastic slurry in the 1 TPD opposed multi-burner entrained flow gasifier for investigation on burner atomization, carbon conversion, syngas composition, slag characterization, and practical operations. The lab-scale data and experience obtained from this project will further encourage the development of technologies and commercial approaches to enable a hydrogen-based energy economy while achieving net-negative CO₂ emissions through gasification of coal, biomass, and carbonaceous mixed wastes such as plastics.

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NH₄OH Looping with Membrane Absorber and Distributed Stripper for Enhanced Algae Growth

The University of Kentucky Institute for Decarbonization and Energy Advancement (UK IDEA) has successfully developed and demonstrated an integrated post-combustion CO₂ capture and utilization system for a fossil fuel power generation that reduces the cost of CO₂ capture and boosts algae production. This innovative process is built upon aqueous ammonia-based looping carbon capture technology with key attributes such as aqueous ammonia solvent applied as both capture reagent and algae nutrient, indirect contact of gas and liquid phase in membrane absorber and downward flow to ensure minimal NH₃ slip and long-term operation with no blockage of the membrane, solar-thermal energy powered solvent regenerators in terms of producing the instantaneous product stream with CO₂/NH₃ supply control strategy and utilized by the algae cultivation in 1100 L open raceway ponds. The integration of solvent regeneration and just-in-time CO₂ and NH₃ delivery to algae with optimized ratio can minimize chemical stress on algae. Additionally, the continuous and thermally compressed CO₂/NH₃ product stream can facilitate sparging into bioreactors for productivity enhancement by higher CO₂ utilization efficiency. These techniques intensify the capture process towards significantly lower capital and operating costs and provide a clear pathway to reduce capture capital and operating costs by 50% and boost algae production by 50%.

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