(534a) Thermodynamic Simulations and Techno-Economic Analysis on the Utilization of CO2 and a Novel Modularization Strategy for Chemical Looping Based Gtl Processes

Authors: 
Kathe, M., The Ohio State University
Fan, L. S., The Ohio State University
Sandvik, P., The Ohio State University
Fryer, C., the Ohio State University
Kong, F., The Ohio State University
Empfiled, A., The Ohio State University
The utilization of carbon dioxide (CO2)as a feedstock in a chemical looping process that converts methane to syngas and a variety of downstream products has the ability to be impactful in the field of carbon capture, utilization, and sequestration (CCUS). The Ohio State University Chemical Looping methane to syngas (MTS) process’ novelty comes from the coupling of carbon capture and utilization strategy, which captures and utilizes CO2 to create a synergy atypical to many processes that are designed to deal with the challenges of carbon constraints. CO2 utilization allows for increased flexibility of H2:CO molar ratios that may be required for variations in the downstream processing while producing a comparable quantity of syngas with reduced natural gas input. In this study, thermodynamic models for chemical looping reactor systems are examined using ASPEN Plus. The chemical looping reducer reactor considered employs steam, natural gas and CO2 as feedstock along with metal oxide oxygen carriers. This presentation will initially present system optimization based on thermodynamic Gibbs free energy minimization for the desired syngas composition required for downstream gas to liquid (GTL) processes. With CO2 co-injection in the MTS process, the thermodynamic optimization indicates a natural gas savings of more than 20% over that of the baseline partial oxidation processes for GTL applications. Experimental verification using Thermo-gravimetric analyzer and bench-scale moving bed reactor that compared well with the thermodynamic model simulations will also be presented. A comprehensive techno-economic analysis on an energy, balanced (water balance, steam balance, heat and electricity balance) thermodynamic performance model of the MTS process with and without CO2 utilization & modularization strategy was developed. The use of techno-economic analysis model for studying sensitivities associated with parameters including capital charge factor, first year versus leveled costs of fuel, crude oil equivalent prices and cost of chemical looping reactors will be presented. The comprehensive techno-economic analysis findings exemplify the importance of a CO2 utilization and modularization strategy in chemical looping GTL processes and encourage further optimization in natural gas to commodity chemical conversion processes including gas to methanol, gas to ammonia, and gas to ethanol, amongst others.