Rankine cycle power plant with two turbine stages; second turbine stage of higher efficiency than first

Claim 2

A Rankine cycle power plant for generating power from a source fluid comprising at least one system having the following components: a preheater responsive to heat in the source fluid 5 for preheating liquid working fluid; a vaporizer responsive to heat in the source fluid for vaporizing preheated liquid working fluid produced by the preheater; a first turbine module having an input for receiving vaporized working fluid produced by the vaporizer and having an output shaft, the first module being 10 responsive to vaporized working fluid from the vaporizer for expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated; a second turbine module having an input and having an output shaft, the second module being responsive to vaporized working fluid for 15 expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated; an electric generator coupled to the output shafts of the turbine modules; and a condenser for condensing heat depleted working fluid produced by the second module into condensate; and means for 20 supplying the condensate to the preheater characterized in that the generator is located between the modules, the heat depleted working fluid produced by the first module is supplied to the inlet of the second module, and the turbine efficiency of the second turbine module is higher than the turbine efficiency of 2 5 the first module. 2.

Claim 3

A Rankine cycle power plant for generating power from a source fluid comprising at least one system having the following components: a preheater responsive to heat in the source fluid 5 for preheating liquid working fluid; a vaporizer responsive to heat in the source fluid for vaporizing preheated liquid working fluid produced by the preheater; a first turbine module having an input for receiving vaporized working fluid produced by the vaporizer and having an output shaft, the first module being 10 responsive to vaporized working fluid from the vaporizer for expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated; a second turbine module having an input and having an output shaft, the second module being responsive to vaporized working fluid for 15 expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated; an electric generator coupled to the output shafts of the turbine modules; and a condenser for condensing heat depleted working fluid produced by the second module into condensate; and means for 20 supplying the condensate to the preheater characterized in that the generator is located between the modules, the heat depleted working fluid produced by the first module is supplied to the inlet of the second module, and the turbine efficiency of the second turbine module is higher than the turbine efficiency of 2 5 the first module. 2.

Claim 4

A Rankine cycle power plant according to claim 1 characterized in that the second turbine module comprises at least one turbine stage whose last stage is effective to substantially isolate upstream stages of said second turbine 30 module from changes in back pressure on the second module. 3.

Claim 5

A Rankine cycle power plant according to claim 2 characterized in that the Mach number of the last stage in the second turbine module is around 1.2 for substantially isolating the upstream stages of said second turbine module from changes in 35 back pressure. 4.

Claim 6

A Rankine cycle power plant according to claim 1 - 14 - £ -T u S ^ ^ characterized in that the electric generator is positioned between the modules and permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed. characterized in that the relatively low speed is 1800 RPM.

Claim 7

A Rankine cycle power plant according to any of the preceding claims characterized in the provision of a second system having the same components as the at least one system, and 10 means for supplying the source fluid to all of the vaporizers of the systems in series to produce heat depleted source fluid; and means for supplying the heat depleted source fluid to all of the preheaters of the systems in parallel. 15 preceding claims characterized in that the working fluid is an organic fluid. 8. A Rankine cycle power plant according to any of the preceding claims characterized in that the source fluid is a medium or low temperature fluid. 20 9. A Rankine cycle power plant according to any of the preceding claims characterized in that the source fluid is a geothermal fluid. 10. A Rankine cycle power plant according to any of the preceding claims characterized in that the source fluid is 25 geothermal hot water. 11. A Rankine cycle power plant according to any of the preceding claims characterized in the provision of a mixer interposed between the modules of each system, the superheated, heat depleted working fluid from one of the modules being 30 transferred to the input of the other of the modules through the mixer; and means supplying for liquid working fluid to the mixer for desuperheating the working fluid supplied to the input of the other of the modules. 5 5. A Rankine cycle power plant according to claim 4

Claim 8

A Rankine cycle power plant according to any of the the Applicon1's^

Claim 9

A Rankine cycle power plant according to any of the the Applicon1's^