Author: Cody Park

Publisher:

Published: 2022

Total Pages: 0

ISBN-13:

Chemical looping partial oxidation is a process technology with the potential to enable clean, sustainable, and cost-effective valorization of hydrocarbon feedstocks to an array of chemical products. In the process scheme, the partial oxidation reaction is partitioned into separate reduction and oxidation reactions facilitated by an oxygen carrying chemical intermediate, referred to here as an oxygen carrier. By utilizing lattice oxygen donation from a metal oxide oxygen carrier in lieu of molecular oxygen, the hydrocarbon fuel can be efficiently converted to high purity syngas. The benefits and impacts of improving the efficiency of syngas generation are propagated through to downstream fuel and chemical synthesis processes. In this study, the chemical looping partial oxidation process for the thermochemical conversion of methane to syngas is investigated at the sub-pilot scale. Performance of the process and identification of viable operating conditions based on thermodynamic criteria is explored through process simulation. The design, construction, commissioning, and operation of a 15 kWth sub-pilot is detailed. In the unit, methane conversion of 99.64% and syngas purity of 97.13% are obtained with a product H2/CO ratio of 1.96. Co-reforming of methane with steam and CO2 is demonstrated, where net CO2 utilization is exhibited and flexible product H2/CO ratio of between 1.19 to 2.50 with high syngas purity is achieved. Finally, considerations for the design of the reactors during scale-up is discussed. The partial oxidation of biomass feedstocks towards the production of liquid fuels is investigated. Gasification of woody biomass and corncob biomass is studied at the sub-pilot scale where 89% carbon conversion and H2/CO ratio between 0.87 to 1.88 is demonstrated. Steam is shown to assist in the conversion of char in the moving bed reducer and suggestions toward commercial design are given. Adiabatic process simulation of the integration of the biomass to syngas process with the Fischer-Tropsch synthesis is investigated and it is shown that the chemical looping process can lead to 13.9% feedstock reduction and 5.7% increase in the lower heating value thermal efficiency relative to a competing gasification process. Finally, application electrical capacitance volume tomography is developed as a measurement technique to monitor and study the multiphase flow dynamics of the chemical looping process: critical to its scale-up and commercialization. A sensitivity gradient-based velocity profiling method is developed and applied to a gas-solid fluidized bed. The velocity profiles are validated against the cross-correlation technique and expected fluidized bed phenomena and breakdown of the method when tracking large objects is revealed and discussed.