Compressor for co2 cycle with at least two cascade compression stages for assuring supercritical conditions

Patent metadata

Field	Value
Publication number	US-2024011493-A1
Application number	US-202118253638-A
Country	US
Kind code	A1
Filing date	Nov 24, 2021
Priority date	Nov 27, 2020
Publication date	Jan 11, 2024
Grant date	—

Abstract

The compressor is used for processing a CO2 flow; a first compressor stage has a first row of blades with a first number of blades and a second compressor stage, downstream the first compressor stage, has a second row of blades with a second number of blades; the number of blades of the first compressor stage is less than the number of blades of the second compressor stage; there is an annular gap between the first row of blades and the second row of blades; the first compression stage ( 200 ) is designed so to assure that the CO2 flow is in supercritical condition, preferably close to CO2 critical point, at its outlet, and so that the second compressor stage process CO2 in supercritical condition.

First claim

1 . A compressor arranged to process a CO2 flow, comprising:
a first compressor stage comprising a first row of rotary blades with a first number of blades; a second compressor stage comprising a second row of rotary blades with a second number of blades, the second compressor stage being fluidly connected downstream said first compressor stage; wherein said first number of blades is less than said second number of blades, and wherein said first stage is arranged to provide at outlet a CO2 flow in supercritical condition; wherein said first row of blades is arranged to provide a CO2 flow directly to said second row of blades; wherein said second row of blades is axially spaced from said first row of blades so that an annular gap is located between said first row of blades and said second row of blades.

2 . The compressor of claim 1 , wherein pressure ratio of said first compressor stage is smaller than pressure ratio of said second compressor stage.

3 . The compressor of claim 1 , wherein pressure ratio of said first compressor stage is more than 1.0 and less than 1.2.

4 . The compressor of claim 1 , wherein the annular gap has an axial length between one and two times a trailing edge height of said first row of blades.

5 . The compressor of claim 1 , wherein a ratio between said second number of blades and said first number of blades is a number higher than 1 and lower than 2 or higher than 2 and lower than 3.

6 . The compressor of claim 1 , further comprising inlet guide vanes upstream said first row of blades.

7 . The compressor of claim 1 , wherein said first row of blades have mainly axial development.

8 . The compressor of claim 1 , comprising a first rotor and a second rotor, wherein said first row of blades is part of said first rotor and said second row of blades is part of said second rotor.

9 . The compressor of claim 1 , comprising a rotor, wherein said first row of blades and said second row of blades are parts of said rotor.

10 . A method for compressing a CO2 flow using a compressor, comprising:
a first compression step for compressing said CO2 flow to a supercritical condition through a first compressor stage so to generate a supercritical CO2 flow; a second compression step for compressing said supercritical CO2 flow through a second compressor stage; wherein said first compression step is such that, at the end of compression, CO2 is close to critical point (Pc, Tc); wherein between the first compression step and the second compression step there is an isoenthalpic step that maintains substantially constant both total pressure and static pressure.

11 . The method of claim 10 , wherein said first compression step is such that, at the end of compression, thermodynamic state point of CO2, on a T-s diagram, is located outside the saturation dome, approximately near CO2 critical point (Pc, Tc).

12 . The method of claim 11 , wherein at the end of said first compression step, the pressure is equal or higher than saturation pressure plus a predetermined pressure margin, said pressure margin being related to pressure drop inside the second rotary compressor stage.

13 . The method of claim 10 , wherein said first compression step is followed by one or more compressing steps of compressing CO2 flow.

14 . The method of claim 10 , wherein said first compression step has a pressure ratio smaller than said second compression step.

15 . An energy generation system based on a supercritical CO2 cycle comprising two heat exchangers, an expander and at least one compressor, said at least one compressor being a compressor according to claim 1 .

Assignees

• Nuovo Pignone Tecnologie Srl

Inventors

• Bellobuono Ernani Fulvio
• Toni Lorenzo
• Grimaldi Angelo
• Rizzo Emanuele
• Valente Roberto

Classifications

• F04D21/00

  Pump involving supersonic speed of pumped fluids · CPC title

• F04D17/12 Primary

  Multi-stage pumps · CPC title

• F04D17/02

  having non-centrifugal stages, e.g. centripetal · CPC title

• F04D25/16

  Combinations of two or more pumps {; Producing two or more separate gas flows} · CPC title

• F04D29/284

  for compressors · CPC title