US 4,996,846 A · Method of and apparatus for retrofitting geothermal power plants

Abstract

An existing geothermal power plant, utilizing geothermal steam from a production well in a geothermal field to drive a multi-stage steam turbine when the available steam pressure from the production well for rated mass for steam through the turbine is less than the design pressure of the turbine, is retrofitted by increasing the mass flow of steam from the production well by an incremental amount. Substantially all of the incremental amount of steam is diverted to an organic fluid Rankine cycle power plant for converting heat in the diverted steam to power and producing waste fluid in the form of steam condensate and non-condensable gases. The waste fluid is injected into a reinjection well in the geothermal field. Preferably, the non-diverted portion of steam is applied to the steam turbine and an intermediate stage of the turbine where the design pressure of the stage matches the steam pressure of the applied steam.

Claims34

Dependent claims

A method for retrofitting an existing geothermal power plant of the type utilizing geothermal steam from a production well in a geothermal field to drive a multi-stage steam turbine connected to a generator for generating electrical power, wherein the available steam pressure from the production well, has decreased over time therefore reducing the power output, said power plant utilizing a water cooled surface or spray condenser for receiving turbine exhaust steam, and an open cooling tower by which most of the condensate produced by the condenser used as make-up water for the cooling tower and therefore is vented to the atmosphere along with non-condensable gases in the condenser, said method comprising the steps of:

(a) increasing the mass flow of steam to the turbine thereby increasing the output of the turbine;
and
(b) applying the steam to an intermediate stage of the turbine where the design pressure matches the steam pressure whereby the increased efficiency of the turbine combined with the greater mass flow increases the power produced by the generator.

A power plant for use with geothermal steam from a production well in a geothermal field, said power plant comprising:

(a) a multi-stage steam turbine having a rated mass flow rate, and having a rated input steam pressure greater than the pressure of the geothermal steam, said steam turbine being connected to an electrical generator for generating electrical power;
(b) means for applying said geothermal steam at said rated flow rate to an intermediate pressure stage of said steam turbine where the design pressure of the stage is substantially the same as the pressure of said geothermal steam;
and
(c) condenser means responsive to steam exhausted from the turbine for condensing the exhaust steam.

1 more element

A power plant comprising:

(a) a production well in a geothermal field for producing geothermal steam;
(b) a multi-stage steam turbine having a rated mass flow rate and a rated input steam pressure, and connected to an electrical generator for generating electrical power;
(c) a first organic fluid Rankine cycle power plant having a vaporizer for producing vaporized organic working fluid, and an organic fluid turbine coupled to an electrical generator and responsive to vaporized working fluid for converting heat in the vaporized working fluid to power, and producing heat depleted working fluid, and an organic fluid condenser responsive to the heat depleted working fluid for producing condensate, and means for returning the condensate to the vaporizer, said vaporizer being constructed and arranged to produce first waste fluid comprising condensed steam and non-condensable gases in the geothermal steam during vaporization of the working fluid;
(d) means for applying geothermal steam in parallel to said steam turbine and to the vaporizer of said first organic fluid Rankine cycle power plant;
(e) condenser means for condensing steam exhausted from the turbine;
and
(f) means for injecting the first waste fluid into a rejection well in the field.

4 more elements

Dependencies are inferred from the claim text.

Method of and apparatus for retrofitting geothermal power plants

Life of this patent

Method of and apparatus for retrofitting geothermal power plants

Life of this patent

Abstract

Claims34