Method for retrofitting a gas turbine power plant

Abstract

A method for retrofitting an already existing gas turbine power plant is provided. The method features at least the following steps: fluidically connecting a gas turbine to a flue gas duct which is suitable for conducting flue gas which is produced by the gas turbine; connecting the flue gas duct to a steam generating unit which is fluidically connected to a water-steam cycle, and via which water-steam cycle a power generating facility can be operated; fluidically connecting a CO2 separation apparatus to the flue gas duct for separating the CO2 from the flue gas in the flue gas duct; and electrically connecting the power generating facility to the CO2 separation apparatus, preferably for the essentially energy-autonomous operation of the CO2 separation apparatus.

Claims

1. A method for retrofitting an already existing gas turbine power plant, wherein the method comprises at least the following: fluidically connecting a field run, simple cycle gas turbine to a flue gas duct suitable for conducting flue gas produced by the gas turbine; connecting the flue gas duct to a steam generating unit which is fluidically connected to a water-steam cycle of a power generating facility; fluidically connecting a CO2 separation apparatus to the flue gas duct for separating CO2 from the flue gas in the flue gas duct, and; electrically connecting the power generating facility to the CO2 separation apparatus, wherein electrical power generated by the water-steam cycle of the power generation facility alone powers the CO2 separation apparatus.

2. The method for retrofitting as claimed in claim 1, wherein the step of electrically connecting the power generating facility to the CO2 separation apparatus comprises electrically connecting the power generating facility to at least one pump of the CO2 separation apparatus.

3. The method for retrofitting as claimed in claim 1, wherein the CO2 separation apparatus includes at least one absorber section and at least one desorber section that is fluidically interconnected with the at least one absorber section.

4. The method for retrofitting as claimed in claim 3, wherein the step of fluidically connecting the CO2 separation apparatus to the flue gas duct comprises fluidically connecting to the at least one absorber section of the CO2 separation apparatus.

5. The method for retrofitting as claimed in claim 1, further comprising thermally connecting the water-steam cycle to the CO2 separation apparatus.

6. The method for retrofitting as claimed in claim 5, wherein the water-steam cycle is thermally connected to a desorber section of the CO2 separation apparatus.

7. The method for retrofitting as claimed in claim 1, further comprising fluidically connecting the CO2 separation apparatus to a CO2 supply network.

8. The method for retrofitting as claimed in claim 7, wherein a desorber section of the CO2 separation apparatus is fluidically connected to the CO2 supply network.

9. The method for retrofitting as claimed in claim 1, further comprising fluidically connecting a cooling circuit to the water-steam cycle, electrically connecting electric energy-consuming components of the cooling circuit to the power generating facility, and transferring thermal energy from water in the water-steam cycle to the CO2 separation apparatus.

10. The method for retrofitting as claimed in claim 1, further comprising fluidically connecting a refrigerating machine downstream to the CO2 separation apparatus, the refrigeration machine designed for condensing water out of a gas flow issuing from the CO2 separation apparatus during operation.

11. The method for retrofitting as claimed in claim 1, further comprising connecting a heat exchanger to the flue gas duct, the heat exchanger designed for transferring heat from the flue gas in the flue gas duct to a gas flow issuing from the CO2 separation apparatus.

12. The method for retrofitting as claimed in claim 1, further comprising connecting to the flue gas duct a cooling device that performs a refrigeration process, the cooling device designed for extracting heat from the flue gas and using the heat for energetically supplying the refrigeration process.

13. The method for retrofitting as claimed in claim 12, wherein the cooling device is connected to the flue gas duct between the steam generating unit and the CO2 separation apparatus.

14. The method for retrofitting as claimed in claim 1, wherein the power generating facility comprises a back-pressure turbine which is connected to a generator.

15. The method for retrofitting as claimed in claim 1, wherein the gas turbine is not modified with regard to its electric power output when being retrofitted.

16. The method for retrofitting as claimed in claim 1, wherein the operating parameters of the gas turbine are not adjusted with regard to the retrofit.

17. The method for retrofitting as claimed in claim 16, wherein the operating parameters of the gas turbine are not adjusted with regard to the operation of the steam generating unit and to the operation of the CO2 separation apparatus.

18. The method for retrofitting as claimed in claim 1, further comprising treating all of the flue gas in the flue gas duct.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In this case, in the drawing:

(2) FIG. 1 shows a first embodiment of the system which is created by means of the inventive method for retrofitting an already existing gas turbine power plant.

(3) FIG. 2 shows a flow diagram for representing the sequence of individual steps according to an embodiment of the method according to the invention.

DETAILED DESCRIPTION OF INVENTION

(4) FIG. 1 shows a first embodiment of a system, having gas turbine 5 and CO.sub.2 separation apparatus, which is created by means of the method according to the invention for retrofitting an already existing gas turbine power plant 1. To this end, a flue gas duct 2 has been connected to a gas turbine 5 and is suitable for discharging the flue gas which issues from the gas turbine 5. The flue gas is directed by means of the flue gas duct 2 to a steam generating unit 10 which by means of thermal contact extracts thermal energy from the flue gas and transfers this thermal energy to a water-steam cycle 11. The fluid flow in the water-steam cycle 11 is maintained by a pump (not provided with a designation in the present case) and after passing through the steam generating unit 10 is fed to a back-pressure turbine 13. By expansion in the back-pressure turbine 13 and also by release of thermal energy for providing mechanical energy in the back-pressure turbine 13, a generator 14, connected to said back-pressure turbine 13, is driven. The electric energy which is generated during operation of the generator 14 is fed via a suitable electrical connection to a separation apparatus 20. The water-steam cycle 11, moreover, has a cooling circuit 15 which is designed for drawing heat from the water-steam cycle 11 and feeding this to the separation apparatus 20. The CO.sub.2 separation apparatus 20 can use this heat for heating suitable parts, especially for heating suitable parts in a desorber section 25. At the same time, the cooling circuit 15 within the water-steam cycle 11 constitutes a suitable heat sink.

(5) After release of thermal energy by means of the flue gas to the steam generating unit 10, the flue gas in the flue gas duct 2 comes into thermal contact with a cooling device 60 and makes this heat capacity available for producing refrigeration capacity. The cooling device 60 is especially constructed as an adsorption or absorption refrigerating machine.

(6) Fluidically downstream, thermal energy is also extracted from the flue gas in the flue gas duct 2 by means of a heat exchanger 50, wherein the heat which is extracted in this way is transferred to the gas flow issuing from the CO.sub.2 separation apparatus 20. The heat is especially transferred to a gas flow issuing from a refrigerating machine 40, which refrigerating machine 40 is fluidically connected downstream to the CO.sub.2 separation apparatus 20.

(7) If, as a result of the previously described thermal conditioning steps, the flue gas in the flue gas duct should still not have been sufficiently cooled for operation of the CO.sub.2 separation apparatus 20, it is also possible to provide additional components which are connected to the flue gas duct 2 and can extract heat from the flue gas flowing therein.

(8) The flue gas which is thermally conditioned in this way is fed to the CO.sub.2 separation apparatus 20. The flue gas is especially fed to an absorber section 24 which is fluidically connected to a desorber section 25. In the absorber section 24, the inflowing flue gas is suitably treated with a scrubbing agent so that the CO.sub.2 is separated from the flue gas. After separation has been carried out, the compound consisting of scrubbing agent and CO.sub.2 is fed to the desorber section 25 by means of a suitable pump 21, wherein the desorber section 25 thermally treats the compound of scrubbing agent and CO.sub.2 in such a way that both substances are separated. This is carried out at temperatures of approximately 100 C. or above. After separation of both substances has been carried out, the CO.sub.2 can be transferred via a suitable discharge line from the CO.sub.2 separation apparatus 20 into a CO.sub.2 supply network 30. The regenerated scrubbing agent is fed in turn from the desorber section to the absorber section 24 in order to again absorb, i.e. wash out, CO.sub.2 there.

(9) The gas flow issuing from the CO.sub.2 separation apparatus 20 is fed according to the embodiment to a refrigerating machine 40 which again extracts thermal energy from the gas flow to such an extent that the water present in the gas flow condenses out. Consequently, the dew point for water of the gas flow issuing from the CO.sub.2 separation apparatus 20 is fallen short of.

(10) The condensed water can be extracted via a suitable drain line. The drain line can also feed the water for intermediate storage to a storage tank, which is not additionally shown, from which a desired quantity of water can also be extracted when the refrigerating machine 40 is not in a position to deliver the demanded quantities at short notice. So, the quantity of liquid water which is produced by the refrigerating machine 40, for example, can also depend upon the ambient temperature. If, for example, water is required to an increasing extent in the event of relatively high ambient temperature, such as during the daytime with full exposure to sunlight, it is advisable to collect water at a time of day at which the ambient temperatures are lower and consequently the provision of liquid water by means of the refrigerating machine 40 can be carried out more efficiently. This is the case during the night-time hours, for example. The water which is collected in this way can especially be fed back again into the CO.sub.2 separation apparatus 20 during a daytime operation with full exposure to sunlight in order to compensate liquid losses there.

(11) For operation of the refrigerating machine 40, electric energy can be supplied to this via a suitable supply line. This electric energy can be provided especially by means of the generator 14 which interacts with the back-pressure turbine 13 for power generation.

(12) The gas issuing from the refrigerating machine 40 is again thermally conditioned in the heat exchanger 50 so that its temperature level is increased. During this, heat from the flue gas which is provided for feeding to the CO.sub.2 separation apparatus 20 is transferred to the gas flow issuing from the refrigerating machine 40. A transfer of heat is necessary since the gas issuing from the refrigerating machine 40 does not have sufficient heat in order to be able to be discharged via a chimney, for example.

(13) FIG. 2 shows a flow diagram for explaining a first embodiment of the method according to the invention for retrofitting an already existing gas turbine power plant 1. According to a first step, a gas turbine 5 is connected to a flue gas duct 2. This connection enables the directed discharging and conducting of the flue gas issuing from the gas turbine 5. According to a second step, the flue gas duct 2 is connected to a steam generating unit 10 which is fluidically connected to a water-steam cycle 11 and is provided for operating a power generating facility 12. Consequently, thermal heat can be extracted from the flue gas in the flue gas duct 2 and can be transferred to the water in the water-steam cycle 11. This thermal heat is converted in a thermal water-steam process into electric energy by means of the power generating facility 12. According to a third step, the flue gas duct is fluidically connected to a CO.sub.2 separation apparatus 20, wherein the CO.sub.2 separation apparatus 20 is preferably suitable for removing CO.sub.2 from the flue gas. The removal enables the directed collection and also the directed discharge of the CO.sub.2 which is produced in this way. According to a further subsequent step of the method according to the embodiment, the power generating facility 12 is electrically connected to the CO.sub.2 separation apparatus 20. Consequently, the electrical components which are comprised by the CO.sub.2 separation apparatus can be supplied and operated by means of the electric current from the power generating facility 12. This in turn increases the efficiency of the overall power plant process since no electric energy has to be supplied from outside for operating the electrical components of the CO.sub.2 separation apparatus 20. Rather, the energy for operating the CO.sub.2 separation apparatus 20 originates from the flue gas of the gas turbine 5, which would anyway be fed in an unused state to the environment. This especially relates to gas turbines 5 which are operated in the sense of a single-cycle arrangement.

(14) Further embodiments are gathered from the dependent claims.