Operating cost and water economy of mixed air steam turbines

In this work an economic evaluation of the operating cost and the water economy of the various commercial MAST (mixed air steam turbines) technologies is carried out. For the water requirements the analysis takes into account either the use of a reverse osmosis desalination plant or the use of a water recovery condenser. The two simulation tools used are the IPP (independent power producers) optimization algorithm and the CAROC (computer aided reverse osmosis calculations) optimization algorithm. Both software tools take into account the capital cost, the fuel cost and the operation and maintenance (O&M) requirements of each candidate scheme (MAST plant or RO desalination plant accordingly) and calculate the least cost configuration. The results indicate that when natural gas is used as a fuel it is more cost effective than gasoil. Also, by the integration of water recovery condenser the operating cost is slightly less than in the case of the use of a reverse osmosis desalination plant. Lastly, the least cost MAST technology is the LOTHECO cycle (LOw Temperature HEat COmbined cycle) with natural gas.