Design of a multi-can carbon-free gas turbine combustor utilizing multiple shell-and-tube OTRs for ZEPP applications

Based on 3-D numerical simulations, the present study presents a design of a multi-can carbon-free gas turbine combustor utilizing multiple oxygen transport reactors (OTRs) of the shell and tube type for zero emission power plant (ZEPP) applications. The design of the gas turbine combustor is calculated based on optimizations of flow configuration (co and counter current), shell side and tube side (feed and sweep) flow rates, inlet fuel concentration in the sweep flow (CH₄ plus CO₂), and membrane tube diameter, pitch (spacing) and length. High-temperature mixed conducting perovskite-type BSCF (Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ) ceramic membrane tubes are used considering square arrangement of the tubes. A mesh was developed and used by the ANSYS Fluent software. A modified oxygen permeation equation was utilized accounting for reacting flow and sub-step membrane surface reactions. Series of user defined functions (UDFs) written in C++ code are compiled and hooked to the software to account for oxygen permeation across the membrane. A modified two-step oxy-combustion reaction kinetics mechanism for methane is applied. The results showed that co-current flow configuration can fit better the application of OTR in gas turbine combustion applications. Based on required power output in the range from 10 to 15 MWe, the final design of the gas turbine combustor is calculated to have 16 cans (OTRs) with 3000 membrane tubes per can and volume of 5.2272 m³ per can.