Cascade organic Rankine cycle plant

An Organic Rankine cycle plant (10, 110, 210) with cascade cycles comprising a first organic Rankine cycle (20, 120, 220) which is configured to operate at high temperature, in which a first organic working fluid carries out a heat exchange with a hot source fluid and at least a second organic Rankine cycle (30, 130, 230, 250) which is configured to operate at a temperature lower than the temperature of the first organic Rankine cycle (20, 120, 220) and in which a second organic working fluid carries out a heat exchange with the same hot source fluid, each organic Rankine cycle (20, 120, 220, 30, 130, 230, 250) comprising:

• at least a feed pump (24, 124, 224, 34, 134, 234, 254) configured to feed the organic working fluid in the liquid phase,
• at least a first preheater (25, 125, 225, 35, 135, 235, 255) configured to preheat the organic working fluid,
• at least an evaporator (21, 121, 221, 31, 131, 231, 251) configured to vaporize the organic working fluid,
• at least an expansion turbine (22, 122, 222, 32, 132, 232, 252) configured to expand the vapor of the organic working fluid,
• at least a condenser (23, 123, 223, 33, 133, 233, 253) configured to bring the organic working fluid back into the liquid phase,
• wherein the evaporator (21, 121, 221) of the first organic Rankine cycle (20, 120, 220) is configured to be fed by the full flow rate (40, 140, 240) of the hot source fluid, while the evaporator (31, 131, 231) and the preheater (35, 135, 235) of said at least one second organic Rankine cycle (30, 130, 230) are configured to be fed only by a first partial flow (43,143, 243) of the hot source fluid, the preheater (25, 125, 225) of said first organic Rankine cycle being configured to be fed only by a remaining second partial flow (42, 142, 242) of the hot source fluid.