Abstract: An ionically conductive ceramic element includes a central unit (703). The central unit (703) is composed of a plurality of integrated manifold and tube modules (IMAT) (22) joined end to end along a central axis (A). Each IMAT module (22) has a tube support portion (804) and a plurality of tubes (802) extending from the first surface (803). The tubes (802) each have a closed end (805) and an open end. The second surface (807) is at least partially open to the atmosphere. The open ends of the tubes (802) are open to the atmosphere through the second surface (807). An interior space (830) is formed in the interior of the IMAT (22) for collecting a desired product gas. A collection tube (710) is operable joined with a first end (714) of the central unit (703) for transporting the desired product gas collected in the interior space (730) of the connected IMAT modules (22).