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CN-122029345-A - Method for operating a turbomachine and corresponding system

CN122029345ACN 122029345 ACN122029345 ACN 122029345ACN-122029345-A

Abstract

The invention relates to a method for operating a turbine (102), wherein the turbine comprises an expander side (110) having an expander inlet (112), an expander outlet (114) and an expander impeller (116), and a compressor side having a compressor inlet (122), a compressor outlet (124) and a compressor impeller (126), wherein the turbine further comprises a shaft (130) and a bearing (140, 142), wherein the expander impeller and the compressor impeller are arranged on the shaft and are connected to each other via the shaft, and wherein the shaft is supported by the bearing, wherein compressor process gas (b) is provided to the compressor inlet for compression and expander process gas (a) is provided to the expander inlet for expansion, wherein sealing gas is provided as a sealing gas stream (c) to the bearing (140, 142) for sealing the bearing, wherein gas after having been used or treated in the turbine is used as a heating gas stream (e) for heating the sealing gas stream. The invention also relates to a corresponding system (100).

Inventors

  • T. Dawal

Assignees

  • 克里奥斯塔股份有限公司

Dates

Publication Date
20260512
Application Date
20241015
Priority Date
20231024

Claims (13)

  1. 1. A method for operating a turbine (102), wherein the turbine comprises an expander side (110) having an expander inlet (112), an expander outlet (114) and an expander impeller (116), and a compressor side (120) having a compressor inlet (122), a compressor outlet (124) and a compressor impeller (126), Wherein the turbine further comprises a shaft (130) and a bearing (140, 142), wherein the expander impeller and the compressor impeller are arranged on the shaft and connected to each other via the shaft, and wherein the shaft is supported by the bearing, Wherein a compressor process gas (b) is provided to the compressor inlet for compression and an expander process gas (a) is provided to the expander inlet for expansion, Wherein a sealing gas is supplied as a sealing gas flow (c) to the bearings (140, 142) to seal the bearings, Wherein the gas after having been used or treated in the turbine is used as a heating gas stream (e) to heat the sealing gas stream, And wherein a portion of the compressor process gas (b) is branched off at the compressor outlet (124) to serve as at least a portion of the heating gas stream (e).
  2. 2. The method of claim 1, wherein a cooling gas (d) is provided to the bearing to cool the bearing, and Wherein at least a portion of the cooling gas (d) is used as at least a portion of the heating gas flow (e) after the bearing has been cooled.
  3. 3. The method according to claim 2, wherein a portion of the compressor process gas (b) is branched off at the compressor outlet (124) for use as the cooling gas (d).
  4. 4. The method according to any of the preceding claims, wherein the heated gas stream (e) is provided to the compressor inlet (122) after having been used to heat the sealing gas stream.
  5. 5. The method according to any of the preceding claims, wherein a portion of the expander process gas (a) is branched off for use as at least a portion of the seal gas stream (c) before providing the expander process gas to the expander inlet (112).
  6. 6. The method according to any one of the preceding claims, wherein the heating gas stream is directed through a heat exchanger (160) to heat the sealing gas stream (c).
  7. 7. A method according to any one of the preceding claims, wherein for start-up and/or shut-down of the turbine: -providing a warm sealing gas as the sealing gas flow to the bearing, or -Heating the sealing gas flow using an external heater, or -Heating the bearing.
  8. 8. A method according to any one of the preceding claims, wherein the bearing is a magnetic bearing, preferably an active magnetic bearing.
  9. 9. A system (100, 200, 300, 400) comprising a turbine (102), wherein the turbine comprises an expander side (110) having a compressor inlet (112), an expander outlet (114) and an expander impeller (116), and a compressor side (120) having a compressor inlet (122), a compressor outlet (124) and a compressor impeller (126), Wherein the turbine further comprises a shaft and a bearing, wherein the expander impeller and the compressor impeller are arranged on the shaft and are connected to each other via the shaft, and wherein the shaft is supported by the bearing, Wherein the system is configured to provide a compressor process gas at the compressor inlet for compression and an expander process gas at the expander inlet for expansion, Wherein the system is configured to provide sealing gas as a flow of sealing gas to the bearing to seal the bearing, and Wherein the system is further configured to use the gas after having been used or treated in the turbine as a heating gas stream, to heat a first sealing gas stream, And is further configured to branch a portion of the compressor process gas at the compressor outlet for use as at least a portion of the heated gas stream.
  10. 10. The system of claim 9, further configured to provide a cooling gas to the bearing to cool the bearing, and to use at least a portion of the cooling gas as at least a portion of the flow of heating gas after the bearing has been cooled, Wherein, preferably, the system is further configured to branch off a portion of the compressor process gas at the compressor outlet for use as the cooling gas.
  11. 11. The system of any of claims 9 or 10, further comprising a heat exchanger, wherein the system is configured to direct the flow of heated gas through the heat exchanger to heat the flow of sealing gas.
  12. 12. The system of any of claims 9 to 11, the system being further configured to, for start-up of the turbine: -providing a warm sealing gas as the sealing gas flow to the bearing, or -Heating the sealing gas flow using an external heater of the system, or -Heating the bearing.
  13. 13. The system of any one of claims 9 to 12, further configured to perform the method of any one of claims 1 to 8.

Description

Method for operating a turbomachine and corresponding system The present invention relates to a method for operating a turbine comprising an expander side and a compressor side, and to a corresponding system. Background Turbines may be used in different applications. For example, in low temperature applications, i.e. applications where the process gas is at a low temperature, such as in facilities for air separation and the like, low temperature turbines, such as turbo-expanders and/or compressors, are often used. Such turbines typically include an expander impeller and/or a compressor impeller fixed to a shaft. Such turbines also typically comprise an inlet or inlet channel at the expansion side configured to direct a working fluid (e.g. a gas like the mentioned process gas) to such an impeller, and an outlet or outlet channel configured to direct said working fluid, e.g. after expansion, from the impeller, e.g. to the outside. Similarly, such turbines may include an inlet or inlet passage and an outlet or outlet passage on the compression side. Bearings (e.g., magnetic bearings) of such turbines are typically supplied with a sealing gas to seal the bearings during operation, which is necessary to prevent the bearings from overcooling during operation if cold or cryogenic process fluids are used. This may require high energy. Furthermore, a part of the mentioned process gas on the expander side can be used at least partly as sealing gas. In this case the sealing gas is usually quite cold and must be heated before being supplied to the bearing. This may also require high energy. A known sealing system is described, for example, in CN113899096 a, which uses an external heat source to regulate the temperature of the sealing gas. Another example of a seal gas heating system is shown in CN 219492612U. It is therefore an object of the present invention to provide a method of improving the energy efficiency of a turbine. Disclosure of Invention This object is achieved by providing a method for operating a turbine and a corresponding system having the features of the independent claims. Embodiments of the invention are subject of the dependent claims and the following description. The present invention relates to a turbine, in particular a cryogenic turbine, wherein the turbine comprises an expander side and a compressor side, the expander side having a compressor inlet, an expander outlet and an expander impeller, the compressor side having a compressor inlet, a compressor outlet and a compressor impeller. Further, such turbines comprise a shaft and a bearing, wherein the expander impeller and the compressor impeller are arranged on the shaft and connected to each other via the shaft, and wherein the shaft is supported by the bearing. Typically, the turbine also includes a housing or housing component, preferably including an expander housing, a compressor housing, and a bearing housing. The working or process gas is provided to the compressor inlet for compression via the compressor wheel (hereinafter also referred to as compressor process gas) and the working or process gas is provided to the expander inlet for expansion by the expander wheel (hereinafter also referred to as expander process gas). The compressed gas is then provided at the compressor outlet and the expanded gas is provided at the expander outlet. It should be noted that the two process gases may be the same or different types of gases. Types of turbines are, for example, centrifugal turbines and radial turbines. For example, cryogenic turbines use working fluids such as gases or process gases (or fluids or process fluids) at cryogenic temperatures, i.e., very low temperatures, e.g., below-100 ℃ or even as low as-230 ℃ or-250 ℃ at the expander outlet or at the compressor inlet. Further, a sealing gas is provided as a sealing gas flow to the bearing to seal the bearing. Preferably, a portion of the expander process gas is branched off to serve as at least a portion of the seal gas stream prior to providing the expander process gas to the expander inlet. For example, such sealing gas may be taken from the expander inlet to be injected into the labyrinth behind the expander impeller. Typically in these applications, the gas is quite cold and needs to be heated above its dew point to avoid condensation and injection of liquid into the labyrinth seal. For this purpose, an electric sealing gas heater may be used, the consumption of which may vary in power from a few kilowatts to hundreds of kilowatts and which may be regulated, for example, with a thyristor control panel. Further, in embodiments, a cooling gas is provided to the bearing to cool the bearing. A portion of the compressor process gas is branched off at the compressor outlet to be used as cooling gas. Typically, such cooling gas is taken from the compressor outlet and used to cool the bearings, and then re-injected into the compressor inlet. It has now been demonstrated that the sealing ga