Assembly having two compressors, method for retrofitting

1. An arrangement comprising:

a first compressor train and a second compressor train for compressing a process fluid,

wherein the first compressor train comprises a first drive and a first compressor,

wherein the second compressor train comprises a second drive and a second compressor,

wherein the first compressor train is not mechanically coupled in torque-transmitting fashion to rotating parts of the second compressor train,

wherein the first compressor and the second compressor are directly connected in fluid-conducting fashion to one another by means of a connecting fluid line, in such a way that the first compressor is arranged upstream of the second compressor,

wherein the first compressor compresses with a pressure ratio between 1.1 and 1.6 before the process fluid is fed to the second compressor,

wherein the second compressor is in the form of a geared compressor comprising a gearing housing on the outside of which are mounted plural spiral housings of respective radial compressor stages, wherein the respective radial compressor stages are arranged sequentially with respect to compressed air flowing therethrough, and

wherein the second compressor is a constituent part of a gas turbine and supplies the compressed air to a turbine of the gas turbine.

2. The arrangement as claimed in claim 1 ,

wherein the second compressor compresses with a pressure ratio between 3 and 60 while the first compressor compresses with the pressure ratio between 1.1 and 1.6.

3. The arrangement as claimed in claim 1 ,

wherein the first drive is either a second gas turbine or a steam turbine or an electric motor.

4. The arrangement as claimed in claim 1 , wherein the second compressor compresses with a pressure ratio that is at least 3.8 times higher than the pressure ratio of the first compressor.

5. The arrangement as claimed in claim 1 ,

wherein the first compressor comprises a fan or a blower.

6. The arrangement as claimed in claim 1 ,

wherein the first compressor comprises at least one first compressor stage and second compressor stage, and

wherein the first drive is arranged between the at least one first compressor stage and the second compressor stage.

7. The arrangement as claimed in claim 1 ,

wherein the first compressor is in the form of an at least two-stage radial compressor comprising a first compressor stage and a second compressor stage,

wherein the first compressor stage and the second compressor stage each comprise an intake side and a wheel disk side, and

wherein a wheel disk side of the first compressor stage faces axially toward a wheel disk side of the second compressor stage, and

wherein intake of the first compressor stage and the second compressor stage occurs in axially opposite directions.

8. The arrangement as claimed in claim 7 ,

wherein the first drive is arranged axially between the wheel disk side of the first compressor stage and the wheel disk side of the second compressor stage.

9. The arrangement as claimed in claim 1 ,

wherein the first compressor train is arranged upstream of a filter and the process fluid is conducted into the second compressor only after passing through the filter.

10. The arrangement as claimed in claim 1 ,

wherein a filter is arranged upstream of the first compressor, and the process fluid is conducted directly from the first compressor into the second compressor without passing the filter.

11. The arrangement as claimed in claim 1 ,

wherein at least one surging protection device is provided between the first compressor and the second compressor,

wherein the at least one surging protection device comprises a closing device, and

wherein, in the event of surging, the closing device closes at least 80% of a flow cross section of the connecting fluid line between the first compressor and the second compressor.

12. The arrangement as claimed in claim 1 ,

wherein at least one surging protection device is provided between the first compressor and the second compressor, wherein the at least one surging protection device comprises a pressure relief device which, in the event of surging of the first compressor and/or of the second compressor, relieves the connecting fluid line between the first compressor and the second compressor, or at least a section of the connecting fluid line between the first compressor and the second compressor, of pressure and/or pressure shocks through an opening and into a pressure sink.

13. The arrangement as claimed in claim 11 ,

wherein the first compressor is an axial compressor.

14. The arrangement as claimed in claim 1 ,

wherein the first compressor is in the form of a radial compressor and no surging protection device is provided upstream of the second compressor.

15. The arrangement as claimed in claim 11 ,

wherein the closing device is designed such that, in the event of a backflow of the process fluid from the second compressor train to the first compressor train, the closing device, driven by the back-flowing process fluid, blocks the connecting fluid line over at least 80% of the flow cross section.

16. The arrangement as claimed in claim 11 ,

wherein the closing device is connected to a slide valve and a mechanical thrust arising from a reverse differential pressure across the closing device moves the slide valve into an opening position, such that the connecting fluid line between the first compressor train and the second compressor train is thereby connected to a pressure sink, such that a release of pressure from the connecting fluid line occurs.

17. A method for retrofitting and/or adding a first compressor train to a second compressor train of an existing installation, the method comprising: providing the first compressor train and the second compressor train for compressing a process fluid, wherein the first compressor train comprises a first drive and a first compressor, wherein the second compressor train comprises a second drive and a second compressor, wherein the first compressor train is not mechanically coupled in torque-transmitting fashion to rotating parts of the second compressor train, directly connecting the first compressor and the second compressor in fluid-conducting fashion to one another by means of a connecting fluid line, in such a way that the first compressor is arranged upstream of the second compressor, wherein the first compressor compresses with a pressure ratio between 1.1 and 1.6 before the process fluid is fed to the second compressor, wherein the second compressor is in the form of a geared compressor comprising a gearing housing on the outside of which are mounted plural spiral housings of respective radial compressor stages, wherein the respective radial compressor stages are arranged sequentially with respect to compressed air flowing therethrough, wherein the second compressor is a constituent part of a gas turbine and supplies the compressed air to a turbine of the gas turbine.

18. The method as claimed in claim 17 , wherein, in a step of the retrofitting, the second compressor is aerodynamically modified such that a pressure ratio of the second compressor is reduced in relation to a state before the retrofitting.