A Perspective on the Process and Turbomachinery Design of Compressed Air Energy Storage Systems
Gianfranco Maffulli, Angelo Grimaldi, Andrew Mc Gillis, Lorenzo Succi, Przemyslaw Przybytko, Nicola Maceli, David Brown, Graham Brook, Scott EarleAbstract
The paper describes Baker Hughes experience in the developing turbomachinery for Hydrostor?s Advanced Compressed Air Energy Storage system.
CAES plants include an air compressing system, followed by an air expander used to recover the stored energy. The expander is obtained from the architecture of Baker Hughes steam turbines, adapted to match the specific process needs. The criticalities that were addressed and solved to derive the expanders from the original steam turbine are presented: the optimization of the inlet and exhaust sections of each segment, the development of the blades for high atmospheric volume flow, and the impacts that thermal transients have on the machine.
Inlet and exhaust sections were arranged according to the layout constraints, to mitigate the effects of the thermal stresses and to reduce the weight of the unit. A single-body configuration was selected to optimize capital expenditures and reduce leakage to atmosphere.
For the new stages the optimization strategy adopted to include the mechanical constraints is discussed and 3D full Navier Stokes Computational fluid dynamics analysis results are reported in nominal and off-design.
Paper includes life analysis of main components, accounting for expected thermal transients driven by fast start-up requirements.
Compressor train is characterized by a multiple body configuration. The optimization of inlet/exhaust nozzles performed to improve the efficiency and the availability of the low-pressure axial compressor is discussed