Rotor for power generation turbine, turbine comprising said rotor and thermodynamic circuit using said turbine

Abstract

The invention discloses a rotor comprising a plurality of rotor discs stacked and connected to each other by a plurality of tie rods. The tie rod includes at least a first tie rod arrangement and a second tie rod arrangement. The first tie rod arrangement includes a plurality of first tie rods parallel to the axis of rotation of the rotor at a first distance from the axis of rotation of the rotor. The second tie rod arrangement may include a set of tie rods arranged parallel to the axis of rotation of the rotor and at a second distance from the axis of rotation of the rotor, the second distance being less than the first distance. Alternatively or in combination, the second tie rod arrangement includes a central tie rod coaxial with the axis of rotation.

Description

[0001] manual Technical Field

[0002] This disclosure relates to gas expanders particularly suitable for oxygen-fueled power cycles (e.g., CO2 cycles, such as the Allam cycle, also known as the NET power cycle) operated under high pressure with process gases. More generally, this disclosure relates to rotors for turbines and turbines including said rotors. Background Technology

[0003] Fossil fuels are the primary source of chemical energy used to generate mechanical power. Fossil fuels are mixed with air and burned to produce high-pressure, high-temperature combustion gases, which expand in a turbine or expander. The expander converts the enthalpy of the combustion gases into mechanical power that can be obtained on the expander's output shaft and used to drive loads, such as compressors or compressor units, or to rotate generators and convert mechanical power into electricity.

[0004] One of the main concerns regarding the combustion of fossil fuels involves the production of carbon dioxide, a greenhouse gas that is considered one of the main causes of global warming and climate change.

[0005] To reduce the environmental impact of power generation through the combustion of fossil fuels, post-combustion carbon dioxide (CO2) capture options have been investigated. CO2 capture facilities have been developed to treat flue gas from gas turbines and remove CO2 from it before it is released into the environment. However, CO2 capture facilities are costly in terms of both CAPEX and the energy required to operate them, which reduces the overall thermodynamic efficiency of the system. The percentage of CO2 in the flue gas is also low. This necessitates processing large volumes of flue gas through CO2 capture facilities, making the capture process particularly inefficient.

[0006] In recent years, the oxy-fuel cycle (also known as the oxy-fuel cycle) has been developed, in which fuel (such as natural gas or another fossil fuel) is blended under high pressure into a mixture of oxidant consisting primarily of oxygen (O2) and carbon dioxide (CO2). The blend of fuel, oxygen, and carbon dioxide is burned in the burner of an expander, producing pressurized flue gas consisting only or almost entirely of carbon dioxide and water.

[0007] The flue gas expands in the expander to generate mechanical power. The exhaust gas discharged from the expander's emission side is cooled in a regenerative heat exchanger and further refrigerated into condensate, which can then be removed from the cooled flue gas. The low-temperature flue gas, mainly or solely composed of carbon dioxide, is pressurized and recirculated through the regenerative heat exchanger toward the expander's burner.

[0008] The oxygen supplied to the expander's burner can be obtained by separating nitrogen from ambient air, resulting in a working fluid primarily composed of oxygen and carbon dioxide, excluding nitrogen. The generated flue gas consists mainly of water and carbon dioxide. Water is removed from the flue gas through condensation, and the portion of anhydrous flue gas that is not recirculated back to the burner can be effectively treated in a carbon dioxide capture unit.

[0009] The oxygen-fuel cycle described above is a semi-closed cycle because only a portion of the flue gas leaves the cycle after water has been removed from it.

[0010] Oxygen-fueled or oxygen-combustion cycles (such as those described above) are of particular interest in terms of efficiency and reduction of harmful emissions. However, oxygen-fueled or oxygen-combustion cycles operate under supercritical CO2 conditions at the expander inlet and are characterized by a high pressure drop across the expander and a high torque applied to the expander rotor. These factors become critical as the expander's rated power increases, posing significant challenges to expander rotor design and potentially limiting the expander's maximum power ratio.

[0011] Novel rotor and turbine designs suitable for achieving higher power ratios, for example, in an oxygen fuel cycle, will be welcomed in the field. Summary of the Invention

[0012] According to one aspect, this document discloses a rotor for a power generation turbine, such as, particularly, a rotor for an expander or a turbine expander. In some embodiments, the expander is an oxy-fuel combustion expander, which is adapted to process supercritical carbon dioxide, for example, at the expander inlet.

[0013] In the embodiments disclosed herein, the rotor includes a plurality of rotor disks stacked together and connected to each other by a plurality of tie rods. Each disk includes a plurality of rotor blades arranged in an annular row around the rotor's axis of rotation. When the rotor is arranged in a turbine, the rotor blades form part of the expansion flow path of the power generation turbine. The tie rods include at least a first tie rod arrangement and a second tie rod arrangement. The first tie rod arrangement includes a plurality of first tie rods parallel to the rotor's axis of rotation at a first distance from the rotor's axis of rotation. The second tie rod arrangement may include a set of tie rods arranged parallel to the rotor's axis of rotation and at a second distance from the rotor's axis of rotation, the second distance being smaller than the first distance. Alternatively or in combination, the second tie rod arrangement includes a central tie rod coaxial with the axis of rotation.

[0014] The twin-strut arrangement provides strong axial restraint between the rotor components. This axial restraint is well-suited to resist the high torque and high pressure typically found in supercritical CO2 power generation turbines, such as expanders for oxy-fuel or oxy-combustion cycles. Similar twin-strut arrangements can be used in other situations where torque and / or pressure conditions are critical.

[0015] The rotor also includes a front shaft section and a rear shaft section; wherein a set of rotor discs is arranged between the front shaft section and the rear shaft section. Each tie rod of the first tie rod arrangement extends from the front shaft section to the rear shaft section and engages the front shaft section and the rear shaft section.

[0016] Further embodiments and features of the rotor are set forth in the appended claims and described below.

[0017] According to another aspect, this document discloses a power generation turbine comprising a rotor as outlined above. In the embodiments disclosed herein, the turbine is an expander, and may be a supercritical CO2 expander, i.e., an expander wherein carbon dioxide is under supercritical conditions at the inlet of the expansion flow path, and / or an expander for an oxygen-fuel combustion cycle (such as the Allam cycle).

[0018] According to another aspect, this document discloses a thermodynamic circuit using a turbine in the form of an expander as outlined above, and is described in more detail in the following description of an exemplary embodiment. Attached Figure Description

[0019] Now, please briefly refer to the attached diagram, in which:

[0020] Figure 1 This is a schematic diagram of an oxygen-fuel power circuit;

[0021] Figure 2 This is a cross-sectional view of the expander according to the present disclosure in the first embodiment;

[0022] Figure 3 It is used in the implementation plan Figure 2 A cross-sectional view of the rotor of the expander;

[0023] Figure 4 This is a cross-sectional view of a rotor for an expander according to another embodiment of the present disclosure;

[0024] Figure 5 This is yet another embodiment of the rotor for an expander according to the present disclosure. Figure 7 A cross-sectional view of line VV;

[0025] Figure 6 It is based on Figure 7 The cross-sectional view of line VI-VI; and

[0026] Figure 7 It is based on Figure 5 and Figure 6 A cross-sectional view of line VII-VII. Detailed Implementation

[0027] Figure 1 The schematic diagram illustrates a simplified supercritical carbon dioxide cycle (sCO2 cycle for short), such as the Allam cycle or similar oxygen-fuel combustion cycles, in which the use of an expander including a rotor according to this disclosure may be particularly advantageous. Generally, as understood herein, a supercritical carbon dioxide cycle is a cycle in which carbon dioxide is under supercritical conditions, at least at the inlet of the expansion flow path in the expander.

[0028] Figure 1 The power system 1 shown includes an expander (also known as a turbine expander) 3, which includes an expansion section 5 and a burner 7. The burner 7 may be, for example, an annular burner, a canister burner, a canister-annular burner, etc. In the currently preferred embodiment, the burner is a canister burner, which includes multiple combustion chambers arranged around the rotation axis of the expander 3, such as... Figure 2 This is shown in more detail below. In some implementations, such as... Figure 2 As schematically shown, the combustion chamber is housed within the high-pressure casing of the expander, as will be described in more detail below. In some embodiments, each combustion chamber is housed in a corresponding support formed within the high-pressure casing of the expander, as will be described in more detail below.

[0029] Figure 2 Reference numeral 7.1 in the figures indicates a single combustion chamber of a canister burner or a canister annular burner. In other embodiments not shown, the burner may be an annular burner, as mentioned.

[0030] The burner 7 is supplied with an oxidant stream from an oxidant source. The oxidant can be oxygen (O2) or a mixture comprising oxygen and carbon dioxide (CO2) or primarily oxygen and carbon dioxide. The oxidant stream can be generated by an air separation unit 9 having an oxidant source. The air separation unit 9 can remove nitrogen or nitrogen and carbon dioxide from ambient air to generate the desired oxidant stream, which is supplied to the burner 7 of the expander 3 via an oxidant line 11. In some embodiments, for easier handling of the oxidant stream, the oxidant stream may comprise approximately 20% by volume oxygen and 80% by volume carbon dioxide. The percentages of CO2 and O2 described above are exemplary. Carbon dioxide can be added to the oxygen via a recirculation line 12, as explained in more detail below.

[0031] Reference numeral 13 indicates a fuel supply line, for example adapted to supply natural gas (such as methane) to burner 7, particularly to each combustion chamber 7.1. Oxidant and fuel are supplied to burner 7 at high pressure at the inlet side of expander 3. The upper limit pressure of the thermodynamic cycle can be, for example, 50 barA or more, preferably 100 barA or more, for example about 200 barA or more, preferably about 250 barA or more, or higher, for example equal to or greater than 300 barA. Generally, the pressure can be below 800 barA or below 650 barA. In some embodiments, the upper limit pressure of the thermodynamic cycle, i.e., the pressure in the burner and at the first expansion stage, can be 100 barA, 150 barA, 200 barA, 250 barA, 300 barA, or 350 barA.

[0032] The oxidizer-fuel blend is combusted in burner 7. The pressurized hot combustion gases produced by combustion expand in expansion section 5 of expander 3. The temperature at the outlet side of the fixed nozzle downstream of the burner can be, for example, between 800°C and 1500°C.

[0033] The exhaust gas expands at the exhaust side of the expander 3 and is then discharged into the exhaust line 15. The exhaust gas in the exhaust line 15 may be at a temperature between about 400°C and about 700°C, for example, at about 600°C, and at a pressure in the range of about 10 barA to about 100 barA, preferably between about 20 barA and about 60 barA.

[0034] The circuit also includes a regenerative heat exchanger 17, through which hot flue gas flowing through the hot side 17.1 is cooled in heat exchange with cooled flue gas flowing through the cold side 17.2 of the regenerative heat exchanger 17. Flue gas exiting from the hot side 17.1 of the regenerative heat exchanger 17 is further cooled in a cooling heat exchanger 19 to a temperature that condenses the vapors contained in the exiting flue gas. Condensate is removed from the exiting flue gas in a water / gas separator 21.

[0035] The dehydrated and refrigerated flue gas, mainly or solely composed of carbon dioxide, is compressed in the flue gas compressor 23 to the pressure at the inlet side of the expander 3. Although in Figure 1 In the schematic diagram, flue gas compressor 23 is illustrated as a single compressor, but in some embodiments, multiple compressors may be used. For example, flue gas compressor 23 may be a multi-stage compressor or a compressor unit. In some embodiments, the compressor may be an intercooled compressor. In some embodiments, the main compressor may be connected in series with two sequentially arranged pumps.

[0036] Compressed flue gas delivered by flue gas compressor 23 is partially removed from the circulation via discharge line 25. If compressor 23 is characterized by multiple compressor turbines arranged in series, discharge line 25 may be connected between two sequentially arranged turbines and / or at the discharge side of the most downstream compressor turbine.

[0037] The remaining compressed flue gas is conveyed through the cold side 17.2 of the regenerative heat exchanger 17 and heated by exchanging heat with the hot flue gas flowing through the hot side 17.1 of the regenerative heat exchanger 17, and then recirculated to the expander 3 via the recirculation line 25. The flue gas recirculated via the recirculation line 25 is mixed with the combustion gases generated in the burner 7, or with the oxidant stream from the oxidant line 11.

[0038] The side flow of cooled flue gas is delivered to the components of the expander 3 that require cooling via cooling line 27, which bypasses the regenerative heat exchanger 17.

[0039] The expander 3 may include an output shaft end 31, which may be integral with the central portion of the rotor, or assembled with the central portion of the rotor via bolted connection, welding, Hirth or spline connection, or a combination thereof. The mechanical power generated by the expansion of the combustion gas in the expansion section 5 of the expander 3 can be used on the output shaft end 31 for mechanical drive or power generation purposes. Figure 1 In an exemplary embodiment, the output shaft end 31 is directly or driveably connected to the generator 33 via a gearbox, connector, or a combination thereof. The flange connection between the output shaft end 31 and the generator 33 is... Figure 2 As shown in Figure 49. Generator 33 is then electrically connected to power distribution network 35. Figure 1 and Figure 2 In the diagram, the output shaft end 31 is shown as being located at the rear of the expander 3. In other embodiments not shown, the output shaft end 31 may be located at the front of the expander. In yet another embodiment not shown, two output shaft ends may be provided, one at the front of the expander and one at the rear.

[0040] As used herein, "front" and "rear" refer to the flow direction of the process gas through the expander 3. Therefore, "front" indicates the position on the burner 7 side, and "rear" indicates the position on the side opposite to the burner 7, i.e., the discharge side of the expander 3.

[0041] The high pressure drop across expander 3, the high absolute pressure in burner 7 and the expander's cooling ducts, and the high torque applied to the expander shaft pose significant challenges to the design of expander 3, particularly for high rated power, such as equal to or about 150 MW or more, such as between 100 MW and 2000 MW. Expanders (particularly the rotor designs disclosed herein) can be used to achieve high power ratios, preferably above 50 MW, such as about 100 MW or higher, such as 150 MW or higher, such as 200 MW or higher, or 300 MW or higher. In embodiments, the rated power can be below 2000 MW, preferably below 1500 MW, such as below 1000 MW, or below 800 MW. For example, the rated power can include between 200 MW and 650 MW. Intermediate values ​​for the upper and lower limits of each of the above ranges are also explicitly disclosed herein.

[0042] Continue to refer to Figure 1 , Figure 2 A cross-sectional view of the expander 3 in one embodiment is shown. As an example, Figure 2 Expanders include those based on Figure 4 The rotor. In other embodiments, Figure 2 The expander may include according to Figure 3 or Figure 5 , Figure 6 and Figure 7 The rotor, as disclosed in more detail below.

[0043] In some embodiments, the expander 3 includes an outer housing 41 that houses the burner 7. In some embodiments, the outer housing 41 includes a body 41.1 (referred to herein as the high-pressure housing) and a closure 41.2 (referred herein as the low-pressure exhaust housing). The high-pressure housing 41.1 may include a body, which may be integral, i.e., may consist of a single piece manufactured, for example, by forging, machining, casting, or a combination thereof. In some embodiments, the high-pressure housing 41.1 may be manufactured by welding multiple components together, preferably mating along a plane orthogonal to the axis of rotation.

[0044] The low-pressure exhaust housing 41.2 can be positioned on the exhaust side (i.e., the rear side) of the expander 3, that is, on the side opposite to the burner 7. The low-pressure exhaust housing 41.2 can be integral, that is, it can consist of a single piece manufactured, for example, by forging, machining, casting, or a combination thereof. In some embodiments, the low-pressure exhaust housing 41.2 can be manufactured in two or more parts, which can be irreversibly connected to each other, for example, by welding, or these parts can be reversibly connected to each other, for example, by means of bolts. For example, the low-pressure exhaust housing 41.2 can be divided into two parts along a plane containing the axis of rotation of the expander.

[0045] The high-pressure housing 41.1 and the low-pressure exhaust housing 41.2 can be connected to each other along a plane P, which is orthogonal to the axis of rotation AA of the rotor 43 supported for rotation in the outer housing 41.

[0046] In some embodiments, the low-pressure exhaust housing 41.2 forms an exhaust volute or exhaust chamber 41.3 through which the exhaust gas is discharged from the expander 3.

[0047] Reference numerals 45 and 47 indicate bearing arrangements that rotatably support the rotor 43. For example, bearing arrangement 45 on the side opposite the burner 7 (i.e., the rear side) may include an axial or thrust bearing combined with a radial bearing, or a bearing with axial-radial bearing capability. Bearing arrangement 47 on the burner side (i.e., the front side) may include a radial bearing. A reverse arrangement is also possible, in which a bearing with axial load capability is arranged on the burner side. Bearing arrangements 45 and 47 may be accommodated in bearing housings, not shown in detail.

[0048] In some embodiments, the rotor 43 is surrounded by one or more inner housings 51, which are fixedly housed within an outer housing 41. Each inner housing 51 may be divided into two parts along a plane parallel to the axis of rotation AA of the rotor 43 (e.g., a plane containing the axis of rotation AA). This arrangement of the inner housings 51 and the outer housing 41 is particularly advantageous when the combustion gases reach high pressures (approximately 200 barA to 300 barA or higher). The integral high-pressure housing 41.1 can withstand the loads generated by the high pressure inside the outer housing, while the inner housing 51 facilitates the installation of fixed guide vanes or fixed blades as described below.

[0049] The pressure drop across expander 3 can be about 150 bar or higher, preferably about 200 bar or higher, for example between 250 bar and 400 bar. To expand the combustion gases generated in burner 7, a large number of expansion stages are preferred. Figures 2 to 7 In one exemplary embodiment, the expander 3 includes eight stages. In other embodiments, different numbers of expansion stages are foreseeable, preferably equal to or greater than four, more preferably equal to or greater than five. In some embodiments, the number of expansion stages may be greater than eight, for example nine, ten, eleven or more, and preferably less than fifteen. The expansion stages form axial expansion flow paths for the process gas expanded in the expander 3.

[0050] Each expansion stage includes a ring of fixed guide vanes or fixed blades 53 fixedly arranged in the outer casing 41. Figure 2In an exemplary embodiment, the fixed blades of the annular row are housed within the inner housing 51. Each expansion stage also includes rotor blades 55 of a corresponding annular row arranged downstream of the fixed blades of the corresponding annular row along an expansion flow path extending in the longitudinal direction from the burner 7 through the expansion section 5 to the exhaust chamber 41.3.

[0051] In some embodiments, the fixed blades 53.1 of the first annular row may be arranged at the exhaust end of the burner 7 and form a nozzle array that guides hot, high-pressure gas from the combustion chamber of the burner to the rotor blades of the first row. The rotor blades of the first annular row, designated 55.1, may be arranged adjacent to the burner 7 directly downstream of the fixed blades 53.1 of the first annular row. The fixed blades 53.8 of the last annular row may be positioned near the exhaust chamber 41.3, upstream of the rotor blades of the last annular row shown at 55.8. Reference numeral 55 generally refers to the rotor blades of any annular row or to such rotor blades.

[0052] Rotor blades 55 form part of rotor 43, i.e., are connected to the rotor to rotate with the rotor shaft. In embodiments, rotor blades 55 in each annular row (i.e., each row 55.i, where i = 1 to 8) are connected to a corresponding rotor disk. Rotor disks are designated by 57.i, where i = 1 to 8. Reference numeral 57 indicates a generic rotor disk. The structure of rotor 43 in different embodiments is as follows: Figures 2 to 7 As shown.

[0053] More specifically, Figure 4 It shows Figure 2 The enlarged view of the rotor shown is as follows, Figure 3 An alternative embodiment of a rotor with a similar structure is shown. Figures 5 to 7 The modified rotor, which will be described in more detail later, is shown in the image. Figures 5 to 7 For clarity, rotor blade 55 has been omitted.

[0054] The rotor blades of each stage may be manufactured separately from the corresponding rotor disk 57 and mechanically mounted on the rotor disk. In other embodiments, the rotor blades and rotor disk of each stage may be manufactured as an integral body, for example, by additive manufacturing. In other embodiments, two design options may be combined. One or more stages may include corresponding integrally manufactured components (including rotor blades and disks), and one or more stages may include a rotor disk and separately manufactured rotor blades mechanically coupled to the rotor disk.

[0055] The rotor discs 57 are connected to each other by tie rods. Figures 2 to 4 In an exemplary embodiment, the tie rod includes a first tie rod arrangement and a second tie rod arrangement, the first tie rod arrangement including a plurality of tie rods 61 and the second tie rod arrangement including a single tie rod 63.

[0056] More specifically, the first tie rod arrangement has tie rods 61 arranged around the rotation axis AA of the rotor 43 at a certain distance from the rotation axis AA. Preferably, all tie rods 61 are positioned at the same distance d1 from the rotation axis AA of the rotor 43. Preferably, the tie rods 61 are distributed around the rotation axis AA of the rotor 43 with a constant angular spacing.

[0057] In these embodiments, the single central tie rod 63 of the second tie rod arrangement is coaxial with the rotor 43.

[0058] In some embodiments, rotor 43 further includes a front axle portion 65 and a rear axle portion 67. Each of the front axle portion 65 and the rear axle portion 67 may include one or more sections connected to each other, for example, by a tie rod.

[0059] In some implementation schemes, see Figure 2 The burner 7 extends around the front axle portion 65. In some embodiments, the exhaust chamber 41.3 extends around the rear axle portion 67.

[0060] In some embodiments, the front axle portion 65 and the rear axle portion 67 are connected to the rotor disk 57 in a stacked configuration via the aforementioned tie rod arrangement.

[0061] More specifically, in Figure 2 and Figure 4 In one embodiment, a first tie rod 61 of the first tie rod arrangement extends through a corresponding through-hole in the rotor disk 57 and includes a first end 61.1 connected to the front shaft portion 65 and a second end 61.2 connected to the rear shaft portion 67. The first end 61.1 and the second end 61.2 of each tie rod 61 are threaded to engage with corresponding nuts 62.1 and 62.2.

[0062] In some embodiments, each rotor disk 57 includes front teeth on each side for torsional engagement with corresponding front teeth of adjacent rotor disks, front shaft portion 65, and / or rear shaft portion 67. The front teeth form Hirth joints between rotor disks 57, between the first rotor disk 57.1 and the front shaft portion 65, and between the last rotor disk 57.8 and the rear shaft portion 67.

[0063] In some embodiments, corresponding sealing discs 68 (also referred to as spacer discs) are positioned between each pair of consecutive (i.e., adjacent) rotor discs 57. If the sealing discs 68 are distributed between the pairs of rotor discs 57, front teeth are provided on the opposite sides of each sealing disc 68, and the consecutively arranged rotor discs 57 are torsionally connected to each other by the inserted sealing discs 68, forming a Hirth joint between the opposite sides of each rotor disc 57 and the corresponding sealing disc 68. As used herein, "torsionally connected" means a connection suitable for transmitting torque between torsionally connected components such that the torsionally connected components rotate as a single body about the rotation axis AA of the rotor.

[0064] Providing a front tooth can facilitate increased torque transmission from the front shaft portion 65 to the first rotor disc 57.1, from the last rotor disc 57.8 to the rear shaft portion 67, and between each rotor disc 57 and adjacent rotor discs or sealing discs 68. In some embodiments, the front tooth may be positioned only in sections of the rotor where the highest torque to be transmitted is desired, i.e., for example, in the most downstream section of rotor 43. The area where the highest torque should be transmitted depends on where the load is applied, i.e., whether it is on the rear side of expander 3 (opposite to burner 7) or on the front side of expander 3 (on one side of burner 7). Output shafts on both sides (rear and front) are also foreseeable.

[0065] Although Figure 2 , Figure 3 and Figure 4 In this embodiment, the sealing disc or spacer 68 extends radially inward between adjacent rotor discs 57. However, in other embodiments, the rotor discs 57 may be stacked in direct contact with each other and may be provided with corresponding Hirth joint front teeth that transmit torque directly from one rotor disc 57 to the adjacent rotor disc 57. In this case, an annular sealing flow channel may be provided between adjacent rotor discs.

[0066] In both cases, the sealing channel or sealing disc 68 provides a seal against the stationary blades to prevent gas leakage to the outside of the expansion flow path defined by the distributed row of stationary blades and rotor blades.

[0067] exist Figure 2 and Figure 4In one exemplary embodiment, the center tie rod 63 has a first threaded end 63.1 that extends through a center hole 65.1 in the front axle portion 65. The center tie rod 63 extends through the disc 57 and has a second threaded end 63.2 that threadedly engages in a threaded blind hole 67.2 in the rear axle portion 67. A nut 71.1 is threadedly engaged on the first threaded end 63.1 of the center tie rod 63 to axially tighten the front axle portion 65, the rear axle portion 67, the eight rotor discs 57.1 to 57.8, and the sealing disc 68 (if present) to each other. In other embodiments not shown, the rear axle portion 67 may have a through hole, and the second threaded end 63.2 of the center tie rod 63 may be engaged by a nut similar to nut 71.1.

[0068] The above-described tie rod arrangement enables enhanced axial connections between the components of rotor 43, which allows the rotor to withstand high axial thrust generated by the pressure drop across expander 3 during operation.

[0069] The enhanced connection achieved through the double tie rod arrangement is also beneficial because it increases the torque that can be transmitted from the rotor to the driven shaft.

[0070] The twin-link arrangement has further beneficial effects on rotor cooling. Cooling is achieved by supplying pressurized cooling fluid to rotor 43. Specifically, in some embodiments, compressed and cooled carbon dioxide can be delivered to the cooling chamber 66 inside rotor 43. For example, it can be supplied by the flue gas compressor 23 through cooling line 27. Figure 1 The pressurized carbon dioxide supplied can be fed into the cooling chamber 66 and can flow through radial holes (not shown) in the rotor 43 to buffer and cool the space 58 between adjacent discs 57. The twin-bar arrangement can withstand the load generated by the high-pressure cooling carbon dioxide supplied to the inside of the rotor 43.

[0071] In some embodiments, the expander 3 includes a balancing drum that is drivenly coupled to the rotor 43. Figure 2 and Figure 4 In one implementation scheme, the balance drum 75 is located at the front end of the rotor 43, between the first expander stage and the front bearing arrangement 47.

[0072] In some implementations, the balance drum 75 is integrally formed with the front axle portion 65.

[0073] In some implementation schemes, such as Figure 2 and Figure 4 As shown, the front axle portion 65 includes two sections 65A and 65B. The two sections 65A and 65B of the front axle portion 65 can be connected to each other by a tie rod. Preferably, as shown... Figure 2 , Figure 2As shown in Figure A, the two sections 65A and 65B are connected to each other by a plurality of tie rods 77 arranged around the rotation axis AA of the rotor 43. The tie rods 77 extend through holes provided in two flanges 75.1 and 75.2 of the two sections 65A and 65B of the front axle portion 65, wherein the flanges 75.1 and 75.2 together form a balance drum 75.

[0074] It is convenient to manufacture the balance drum by dividing it into balance drum parts 75.1, 75.2, for example by forging, and it provides the possibility of assembling and tightening the center tie rod 63.

[0075] Continue to refer to Figure 2 and Figure 4 ,exist Figure 3 Another embodiment of the rotor 43 of the expander 3 is shown in the figure. Figure 2 , Figure 4 and Figure 3 The same reference numerals in the figures are used to denote the same or equivalent parts, components or elements of rotor 43, which will not be described again.

[0076] Figure 3 Rotor 43 and Figure 2 and Figure 4 The main difference in the rotor is that the second threaded end 63.2 of the central tie rod 63 engages in the through hole 64.1 of the inner flange 64 integrally formed with the disc 57.6. The nut 71.2 is screwed onto the threaded end 63.2 of the central tie rod 63.

[0077] In this implementation, the central tie rod 63 helps to distribute the axial force connecting only some of the rotor disks to each other. Specifically, in Figure 3 In the illustrated embodiment, the central tie rod 63 connects rotor discs 57.1 to 57.6, the corresponding sealing discs 68, and the front shaft portion 65 of rotor 43. This block is mechanically connected to the remaining discs 57.7 and 57.8 via tie rods 61 arranged in the first tie rod configuration, and to the rear shaft portion 67.

[0078] While in the above embodiment the second tie rod arrangement includes a single central tie rod 63 coaxial with the rotor 43, in other embodiments the second tie rod arrangement may include multiple second tie rods as an alternative to or in combination with the central tie rod. The second tie rods are arranged about the rotation axis AA of the rotor 43 and extend parallel to the rotation axis in exactly the same manner as the tie rod 61 of the first tie rod arrangement.

[0079] Figure 5 , Figure 6 and Figure 7 An embodiment of a second tie rod arrangement including multiple tie rods is shown, wherein Figure 7It is a cross-section of the rotor based on a plane orthogonal to the rotation axis AA of rotor 43. Figure 5 , Figure 6 and Figure 7 The same reference numerals are used to indicate that they have been combined. Figure 2 , Figure 3 and Figure 4 Similar or corresponding parts, components, or parts will be described. These parts will not be described again.

[0080] Figure 5 , Figure 6 and Figure 7 The second tie rod arrangement shown is positioned at a distance d2 from the rotation axis AA of rotor 43. Distance d2 is less than distance d1. Figure 5 , Figure 6 and Figure 7 In one embodiment, the tie rod 63 extends axially from the front axle portion 65 to the rear axle portion 67 and engages both the front and rear axle portions. In other embodiments not shown, the tie rod 63 may have a shorter axial length and be compatible with... Figure 3 It engages with the inner flange of one of the rotor disks (e.g., the sixth rotor disk 57.6) in exactly the same manner as shown.

[0081] Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. Those skilled in the art will understand that various changes, omissions, and additions may be made to the specific disclosure herein without departing from the scope of the invention as defined in the following claims.

[0082] For example, while in the embodiments disclosed herein the burner is housed within the expander, in other embodiments the burner may be arranged outside the expander.

[0083] In some other embodiments, the expander disclosed herein can be used in closed-loop thermodynamic cycles, such as supercritical carbon dioxide cycles, in which heat is introduced into the thermodynamic cycle via a heat exchanger rather than a burner.

[0084] Furthermore, although in the illustrated embodiment the rear axle portion 67 is manufactured as a single, integral body, in other embodiments the rear axle portion 67 may be divided into two or more sections in exactly the same manner as the front axle portion 65. These two sections can be connected to each other by the same tie rod 63. Alternatively, an additional rod, similar to rod 77, can connect the two sections of the rear axle portion 67 to each other.

Claims

1. A rotor for a power generation turbine, the rotor comprising: A set of rotor disks; wherein each rotor disk comprises rotor blades in a corresponding annular row of rotor blades in the expansion flow path of the power generation turbine; The rotor blades of each annular row are arranged around the axis of rotation of the rotor; and A front axle section and a rear axle section; wherein a set of rotor disks is arranged between the front axle section and the rear axle section; The front axle portion, the rear axle portion, and the rotor disk are stacked and connected to each other by a plurality of tie rods, the plurality of tie rods comprising at least: A first tie rod arrangement, comprising a plurality of first tie rods, wherein the plurality of first tie rods are parallel to the rotation axis of the rotor at a first distance from the rotation axis of the rotor; and A second tie rod arrangement; wherein the second tie rod arrangement includes: (i) A set of tie rods arranged parallel to the rotation axis of the rotor and at a second distance from the rotation axis of the rotor, the second distance being less than the first distance; or (ii) A central tie rod, said central tie rod being coaxial with the rotation axis of the rotor; or (iii) A set of tie rods and a central tie rod, the set of tie rods being arranged parallel to the rotation axis of the rotor and at a second distance from the rotation axis of the rotor, the second distance being less than the first distance, and the central tie rod being coaxial with the rotation axis of the rotor; And each of the first pull rods extends from the front axle portion to the rear axle portion and engages the front axle portion and the rear axle portion.

2. The rotor according to claim 1, wherein the central tie rod has a first end engaging the front axle portion and a second end engaging the rear axle portion.

3. The rotor of claim 1, wherein the central tie rod has a first end that engages one of the front shaft portion and the rear shaft portion; and wherein the central tie rod has a second end that engages one of the rotor disks located between the front shaft portion and the rear shaft portion.

4. The rotor of claim 3, wherein the first end of the central tie rod engages the front axle portion.

5. The rotor of claim 1, wherein each of the second tie rods extends from the front axle portion to the rear axle portion and engages the front axle portion and the rear axle portion.

6. The rotor according to one or more of the preceding claims, wherein the rotor further comprises a sealing disc inserted between adjacent rotor discs and torsionally connected to the adjacent rotor discs.

7. The rotor according to one or more of the preceding claims, wherein at least one of the rotor disks includes front teeth adapted to rotatably connect the rotor disk to at least one of: an adjacent rotor disk, a front shaft portion, a rear shaft portion and an adjacent sealing disk, or any combination thereof.

8. The rotor according to one or more of the preceding claims, wherein the rotor further comprises a balancing drum.

9. The rotor according to claim 8, wherein the balance drum is formed on one of the front shaft portion and the rear shaft portion, preferably on the front shaft portion.

10. The rotor of claim 9, wherein the balancing drum comprises a first balancing drum portion and a second balancing drum portion, the first balancing drum portion and the second balancing drum portion being connected to each other by at least one tie rod and preferably by a plurality of tie rods arranged peripherally around the rotation axis of the rotor.

11. The rotor according to one or more of the preceding claims, wherein the rotor comprises at least four expander stages, preferably at least five expander stages.

12. The rotor according to one or more of the preceding claims, wherein the rotor includes an axial cooling chamber adapted to receive cooling fluid and radially fluidly connected to an annular spacer between adjacent discs of the rotor.

13. A power generation turbine, the power generation turbine comprising: External casing; Multiple annular rows of fixed blades are arranged in the housing; and The rotor according to any one of the preceding claims is housed and rotates within the housing; The rotor blades of each annular row and the fixed blades of the corresponding annular row upstream therefrom form the expansion stage of the expansion flow path.

14. The turbine of claim 13, wherein the turbine is a power generation turbine, particularly a gas turbine or expander.

15. The turbine according to claim 13 or 14, wherein the outer casing comprises a high-pressure casing and a low-pressure exhaust casing; wherein the high-pressure casing and the low-pressure exhaust casing are connected along a plane orthogonal to the axis of rotation of the rotor.

16. The turbine of claim 15, wherein the high-pressure housing comprises an integral barrel.

17. The turbine of claim 15 or 16, wherein the low-pressure exhaust casing is constructed as an integral body.

18. The turbine according to any one of claims 13 to 17, the turbine further comprising at least one burner housed in the outer casing.

19. The turbine of claim 18, when subordinate to claim 16, wherein the at least one burner is housed in a support formed in the high-pressure housing.

20. The turbine of claim 19, wherein the low-pressure exhaust casing is disposed on the low-pressure side of the expander, opposite to the combustor; and wherein the low-pressure exhaust casing forms an exhaust chamber.

21. The turbine according to any one of claims 13 to 20, the turbine further comprising at least one inner housing, and preferably comprising a plurality of inner housings, the at least one inner housing being fixedly housed in the outer housing and surrounding the rotor; wherein each inner housing is divided into a first housing portion and a second housing portion along a plane parallel to the axis of rotation of the rotor; and wherein the inner housing comprises a fixed blade in an annular row.

22. The turbine according to any one of claims 13 to 21, wherein the rotor is adapted to receive process gas with a temperature T between 800°C and 1500°C.

23. The turbine according to any one of claims 13 to 22, wherein the rotor is adapted to receive process gas with a pressure higher than 50 barA, preferably higher than 100 barA, more preferably equal to or higher than 200 barA, and preferably lower than 800 barA, more preferably lower than 650 barA.

24. The turbine according to any one of claims 13 to 23, wherein the turbine is adapted to generate power of more than 50 MW, preferably equal to or greater than 100 MW, preferably less than 2000 MW, and more preferably less than 1500 MW.

25. A supercritical carbon dioxide thermodynamic circuit, the supercritical carbon dioxide thermodynamic circuit comprising: Oxidizing agent source; An expander having an inlet side and an outlet side, wherein the inlet side is fluidly connected to the oxidant source; A flue gas recirculation line, the flue gas recirculation line being adapted to recirculate flue gas from the exhaust side of the expander to the burner of the expander; A cooler, located in the flue gas recirculation line, is adapted to cool the flue gas from the exhaust side of the expander and condense water contained in the flue gas. A regenerative heat exchanger in which the flue gas from the expander exchanges heat with the quenched flue gas from the cooler; The expander thereon is an expander according to any one of claims 13 to 24.

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