Recuperators for the HHT-Demonstration Plant

Recuperators of closed cycle gas turbine plants are characterized by large heat transfer areas accommodated in rather small volumes. Clean gas conditions, moderate operating temperatures and modest requirements with respect to tightness have resulted in generally good operational records. In the case of recuperators for direct cycle high temperature reactors, more stringent boundary conditions are being imposed than for conventional plants. In this paper studies and experiments performed for the recuperator of the HHT demonstration plant (670 MWe) are described. Five different design concepts are discussed and mutually compared. All designs use straight tubes. The main concept is a proposal with longitudinal flow on the shell side, but also the proven cross-counterflow concept has its merits. Special subjects are sensitivity to temperature streaks and optimum subdivision into modules.