Forced flow vapor generator plant

A forced flow vapor generator plant comprising

• treatment means for desalinating a flow of water to a conductivity of less than 0.2 microsiemens per centimeter and to a silicon content of less than 0.02 parts per million;
• a high pressure feed pump for pumping a flow of water from said treatment means;
• a vapor generator having a plurality of vertical tubes disposed in seal-tight relation to each other to define an evaporator about a combustion chamber, a plurality of vertical tubes disposed in seal-tight relation to each other and to said evaporator tubes to define a first superheater about a flue above said combustion chamber, an economiser within said flue connected to and between said feed pump and said evaporator to deliver a heated flow of water to said evaporator, and a final evaporator within said flue upstream of said economiser and connected to said evaporator to receive a mixture of water and vapor therefrom;
• and
• a water-separating means connected to said final evaporator to receive a mixture of water and vapor therefrom, said water-separating means having a return line communicating with a position between said treatment means and said evaporator for returning separated water thereto and a tube communicating with said first superheater to deliver vapor thereto whereby the plant is operable on a once-through flow through said evaporator in a load range above 50% of full load.