Design of an ion transport membrane reactor for gas turbine combustion application

Abstract

The use of ion transport membrane reactors to substitute the conventional gas turbine combustors is a promising technology for the applications of ZEPP. An ITM monolith structure reactor design is introduced in this study for substituting a conventional gas turbine combustor. Due to reactor symmetry, only 3D four quarters of four adjacent channels sharing one common edge are considered in all simulations using LSCF1991 membranes. Effect of feed and sweep flow rates have been considered and it was calculated in order to meet the power required for the reactor and keeping the reactor size as compact as possible. Effects of flow configurations, channel width and percentage of CH4 in the permeate side flow are introduced under constant inlet gas temperature of 1173K and fixed operating pressure of 1000000 Pa. The reactor geometry has been calculated based on the calculations of the minimum possible channel width. Counter-current flow configuration design resulted in improved oxygen permeation flux and improved heat transfer characteristics. However, this flow configuration resulted in unacceptable increase in the membrane temperature. It was found that any reduction in the channel width below 15mm results in large increase in the viscous pressure drop. Also, increasing the amount of CH4 in the permeate side over 5% was found to be non-applicable because of oxygen permeation flux limitation. The reactor length was fixed to 0.9m to be similar to that of real gas turbine combustors with 25,000 channels for each stream. The present reactor design resulted in a reactor height of 3.35m and overall volume and membrane surface area of 10m3 and 2700m2, respectively. The reactor is capable of delivering power ranging from 5 to 8MWe based on cycle first law efficiency.