In a direct comparison of OTSG vs Drum-type HRSGs for Cogen applications, here is a typical result:
The capital cost for an OTSG is typically lower than a traditional drum-style HRSG when evaluated on an installed basis. An even greater benefit which is often overlooked is the reduction in life cycle costs. The OSTG has significantly reduced maintenance requirements, no blow-down systems, no exhaust gas bypass stack or diverter system, faster start-ups, and many more important operational efficiencies. The inherent flexibility of the OTSG allows plant owners to minimize the cost of each MW they produce.