Patent Application
20160281732
Compressors and systems including compressors have been developed and are utilized in a myriad of industrial processes (e.g., petroleum refineries, offshore oil production platforms, and subsea process control systems) to compress gas, typically by applying mechanical energy to the gas in a low pressure environment and transporting the gas and compressing the gas to a higher pressure environment. The compressed gas may be utilized to perform work or as an element in the operation of one or more downstream process components. As conventional compressors are increasingly used in offshore oil production facilities and other environments facing space constraints, there is an ever-increasing demand for smaller, lighter, and more compact compressors. In addition to the foregoing, it is desirable for commercial purposes that the compact compressors achieve higher compression ratios (e.g., 10:1 or greater) while optimizing efficiency and maintaining a compact arrangement.
In view of the foregoing, skilled artisans have proposed approaches to improve the efficiency of the compact compressors, many of which in the case of compact centrifugal compressors relate to the blading of one or more impellers operating therein. One such approach has included the use of splitter blades mounted to the impeller, such that each splitter blade is disposed equidistantly between adjacent full blades mounted to and extending from the hub of the impeller; however, such an approach has been determined to result in unequal mass flow in channels formed between the splitter blades and the adjacent full blades, thus resulting in efficiency losses.
What is needed, therefore, is an efficient compression system that provides increased compression ratios in a compact arrangement that is economically and commercially viable.
Embodiments of the disclosure may provide an impeller for a compressor. The impeller may include a hub mountable to a rotary shaft of the compressor and configured to rotate about a center axis. The hub may include a first meridional end portion and a second meridional end portion. The impeller may also include a plurality of main blades mounted to or integral with the hub. The plurality of main blades may be arranged equidistantly and circumferentially about the center axis. The impeller may further include a plurality of splitter blades mounted to or integral with the hub. The plurality of splitter blades may be arranged equidistantly and circumferentially about the center axis. Each splitter blade may include a leading edge meridionally spaced from the first meridional end portion and a trailing edge proximal the second meridional end portion. A splitter blade may be positioned between a first adjacent main blade and a second adjacent main blade and canted such that the leading edge of the splitter blade is displaced from a blade position equidistant the first adjacent main blade and the second adjacent main blade a first percentage amount of one half an angular distance between the first adjacent main blade and the second adjacent main blade. The trailing edge of the splitter blade may be displaced from the blade position equidistant the first adjacent main blade and the second adjacent main blade a second percentage amount of one half the angular distance between the first adjacent main blade and the second adjacent main blade. The second percentage amount may be greater or less than the first percentage amount.
Embodiments of the disclosure may further provide a compressor. The compressor may include a housing and an inlet coupled to or integral with the housing and defining an inlet passageway configured to receive and flow a process fluid. The compressor may also include a rotary shaft configured to be driven by a driver, and a centrifugal impeller coupled with the rotary shaft and fluidly coupled to the inlet passageway. The centrifugal impeller may be configured to rotate about a center axis and impart energy to the process fluid received via the inlet passageway. The centrifugal impeller may include a hub defining a borehole through which a coupling member or the rotary shaft of the supersonic compressor extends. The hub may include a first meridional end portion having an annular portion and a second meridional end portion forming a disc-shaped portion. The centrifugal impeller may also include a plurality of blades mounted to or integral with the hub. The plurality of blades may be arranged equidistantly and circumferentially about the center axis and include a splitter blade positioned between a first adjacent main blade and a second adjacent main blade and canted with respect to the first adjacent main blade and the second adjacent main blade. The compressor may further include a static diffuser circumferentially disposed about the centrifugal impeller and configured to receive the process fluid from the centrifugal impeller and convert the energy imparted to pressure energy. The compressor may also include a collector fluidly coupled to and configured to collect the process fluid exiting the static diffuser, such that the compressor is configured to provide a compression ratio of at least about 8:1.
Embodiments of the disclosure may further provide a compression system. The compression system may include a driver including a drive shaft. The driver may be configured to provide the drive shaft with rotational energy. The compression system may also include a supersonic compressor operatively coupled to the driver via a rotary shaft integral with or coupled with the drive shaft and configured to rotate about a center axis. The supersonic compressor may include a compressor chassis and an inlet defining an inlet passageway configured to flow a process fluid therethrough. The process fluid may have a first velocity and a first pressure energy. The supersonic compressor may further include a centrifugal impeller coupled with the rotary shaft and fluidly coupled to the inlet passageway. The centrifugal impeller may have a tip and may be configured to increase the first velocity and the first pressure energy of the process fluid received via the inlet passageway and discharge the process fluid from the tip in at least a partially radial direction having a second velocity and a second pressure energy. The second velocity may be a supersonic velocity having an absolute Mach number of about one or greater. The centrifugal impeller may include a hub defining a borehole through which a coupling member or the rotary shaft of the supersonic compressor extends. The hub may include a first meridional end portion having an annular portion and a second meridional end portion forming the tip. The centrifugal impeller may also include a plurality of blades mounted to or integral with the hub. The plurality of blades may be arranged equidistantly and circumferentially about the center axis and include a splitter blade positioned between a first adjacent main blade and a second adjacent main blade and canted with respect to the first adjacent main blade and the second adjacent main blade. The supersonic compressor may also include a static diffuser circumferentially disposed about the tip of the centrifugal impeller and defining an annular diffuser passageway configured to receive and reduce the second velocity of the process fluid to a third velocity and increase the second pressure energy to a third pressure energy, the third velocity being a subsonic velocity. The supersonic compressor may further include a discharge volute fluidly coupled to the annular diffuser passageway and configured to receive the process fluid flowing therefrom, such that the supersonic compressor is configured to provide a compression ratio of at least about 8:1.
The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Additionally, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein.
The compression system 100 may also include, amongst other components, a driver 104 operatively coupled to the compressor 102 via a drive shaft 106. The driver 104 may be configured to provide the drive shaft 106 with rotational energy. In an exemplary embodiment, the drive shaft 106 may be integral with or coupled with a rotary shaft 108 of the compressor 102, such that the rotational energy of the drive shaft 106 is imparted to the rotary shaft 108. The drive shaft 106 may be coupled with the rotary shaft 108 via a gearbox (not shown) including a plurality of gears configured to transmit the rotational energy of the drive shaft 106 to the rotary shaft 108 of the compressor 102, such that the drive shaft 106 and the rotary shaft 108 may spin at the same speed, substantially similar speeds, or differing speeds and rotational directions.
The driver 104 may be a motor and more specifically may be an electric motor, such as a permanent magnet motor, and may include a stator (not shown) and a rotor (not shown). It will be appreciated, however, that other embodiments may employ other types of electric motors including, but not limited to, synchronous motors, induction motors, and brushed DC motors. The driver 104 may also be a hydraulic motor, an internal combustion engine, a steam turbine, a gas turbine, or any other device capable of driving the rotary shaft 108 of the compressor 102 either directly or through a power train.
In an exemplary embodiment, the compressor 102 may be a direct-inlet centrifugal compressor. In other embodiments, the compressor 102 may be a back-to-back compressor. The direct-inlet centrifugal compressor may be, for example, a version of a Dresser-Rand Pipeline Direct Inlet (PDI) centrifugal compressor manufactured by the Dresser-Rand Company of Olean, New York. The compressor 102 may have a center-hung rotor configuration or an overhung rotor configuration, as illustrated in
The compressor 102 may include one or more stages (not shown). In at least one embodiment, the compressor 102 may be a single-stage compressor. In another embodiment, the compressor 102 may be a multi-stage centrifugal compressor. Each stage (not shown) of the compressor 102 may be a subsonic compressor stage or a supersonic compressor stage. In an exemplary embodiment, the compressor 102 may include a single supersonic compressor stage. In another embodiment, the compressor 102 may include a plurality of subsonic compressor stages. In yet another embodiment, the compressor 102 may include a subsonic compressor stage and a supersonic compressor stage. Any one or more stages of the compressor 102 may have a compression ratio greater than about 1:1. For example, any one or more stages of the compressor 102 may have a compression ratio of about 1.1:1, about 1.2:1, about 1.3:1, about 1.4:1, about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about 1.9:1, about 2:1, about 2.1:1, about 2.2:1, about 2.3:1, about 2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, about 3:1, about 3.1:1, about 3.2:1, about 3.3:1, about 3.4:1, about 3.5:1, about 3.6:1, about 3.7:1, about 3.8:1, about 3.9:1, about 4:1, about 4.1:1, about 4.2:1, about 4.3:1, about 4.4:1, about 4.5:1, about 4.6:1, about 4.7:1, about 4.8:1, about 4.9:1, about 5:1, about 5.1:1, about 5.2:1, about 5.3:1, about 5.4:1, about 5.5:1, about 5.6:1, about 5.7:1, about 5.8:1, about 5.9:1, about 6:1, about 6.1:1, about 6.2:1, about 6.3:1, about 6.4:1, about 6.5:1, about 6.6:1, about 6.7:1, about 6.8:1, about 6.9:1, about 7:1, about 7.1:1, about 7.2:1, about 7.3:1, about 7.4:1, about 7.5:1, about 7.6:1, about 7.7:1, about 7.8:1, about 7.9:1, about 8.0:1, about 8.1:1, about 8.2:1, about 8.3:1, about 8.4:1, about 8.5:1, about 8.6:1, about 8.7:1, about 8.8:1, about 8.9:1, about 9:1, about 9.1:1, about 9.2:1, about 9.3:1, about 9.4:1, about 9.5:1, about 9.6:1, about 9.7:1, about 9.8:1, about 9.9:1, about 10:1, about 10.1:1, about 10.2:1, about 10.3:1, about 10.4:1, about 10.5:1, about 10.6:1, about 10.7:1, about 10.8:1, about 10.9:1, about 11:1, about 11.1:1, about 11.2:1, about 11.3:1, about 11.4:1, about 11.5:1, 11 3.6:1, about 11.7:1, about 11.8:1, about 11.9:1, about 12:1, about 12.1:1, about 12.2:1, about 12.3:1, about 12.4:1, about 12.5:1, about 12.6:1, about 12.7:1, about 12.8:1, about 12.9:1, about 13:1, about 13.1:1, about 13.2:1, about 13.3:1, about 13.4:1, about 13.5:1, about 13.6:1, about 13.7:1, about 13.8:1, about 13.9:1, about 14:1, or greater. In an exemplary embodiment, the compressor 102 may include a plurality of compressor stages, where a first stage (not shown) of the plurality of compressor stages may have a compression ratio of about 1.75:1 and a second stage (not shown) of the plurality of compressor stages may have a compression ratio of about 6.0:1.
The drive shaft 106 of the driver 104 and the rotary shaft 108 of the compressor 102 may be supported, respectively, by one or more radial bearings 118, as shown in
As shown in
In one or more embodiments, the inlet guide vanes 122 may be moveably coupled to the housing 110 and disposed within the inlet passageway 114 as disclosed in U.S. Pat. No. 8,632,302, the subject matter of which is incorporated by reference herein to the extent consistent with the present disclosure. The inlet guide vanes 122 may be further coupled to an annular inlet guide vane actuation member (not shown), such that upon actuation of the annular inlet vane actuation member, each of the inlet guide vanes 122 coupled to the annular inlet guide vane actuation member may pivot about the respective coupling to the housing 110, thereby adjusting the flow incident on components of the compressor 102. As configured, the inlet guide vanes 122 may be adjusted without disassembling the housing 110 in order to adjust the performance of the compressor 102. Doing so without disassembly of the compressor 102 saves time and effort in optimizing the compressor 102 for a particular operating condition. Furthermore, the impact of alternate vane angles on overall flow range and/or peak efficiency may be assessed and optimized for increased performance, and a matrix of inlet guide vane angles may be produced on a relatively short cycle time relative to conventional compressors such that the data may be analyzed to determine the best combination of inlet guide vane angles for any given application.
The compressor 102 may include a centrifugal impeller 126 configured to rotate about a center axis 128 within the housing 110. In an exemplary embodiment, the centrifugal impeller 126 includes a hub 130 and is open or “unshrouded.” In another embodiment, the centrifugal impeller 126 may be a shrouded impeller. The hub 130 may include a first meridional end portion 132, generally referred to as the eye of the centrifugal impeller 126, and a second meridional end portion 134 having a disc shape, the outer perimeter of the second meridional end portion 134 generally referred to as the tip 136 of the centrifugal impeller 126. The disc-shaped, second meridional end portion 134 may taper inwardly to the first meridional end portion 132 having an annular shape. The hub 130 may define a bore 138 configured to receive a coupling member 140, such as a tiebolt, to couple the centrifugal impeller 126 to the rotary shaft 108. In another embodiment, the bore 138 may be configured to receive the rotary shaft 108 extending therethrough.
As shown in
The centrifugal impeller 126 may be operatively coupled to the rotary shaft 108 such that the rotary shaft 108, when acted upon by the driver 104 via the drive shaft 106, rotates, thereby causing the centrifugal impeller 126 to rotate such that process fluid flowing into the inlet passageway 114 is drawn into the centrifugal impeller 126 and accelerated to the tip 136, or periphery, of the centrifugal impeller 126, thereby increasing the velocity of the process fluid. In one or more embodiments, the process fluid at the tip 136 of the centrifugal impeller 126 may be subsonic and have an absolute Mach number less than one. For example, the process fluid at the tip 136 of the centrifugal impeller 126 may have an exit absolute Mach number less than one, less than 0.9, less than 0.8, less than 0.7, less than 0.6, or less than 0.5. Accordingly, in such embodiments, the compressor 102 discussed herein may be “subsonic,” as the centrifugal impeller 126 may be configured to rotate about the center axis 128 at a speed sufficient to provide the process fluid at the tip 136 thereof with an exit absolute Mach number of less than one.
In one or more embodiments, the process fluid at the tip 136 of the centrifugal impeller 126 may be supersonic and have an exit absolute Mach number of one or greater. For example, the process fluid at the tip 136 of the centrifugal impeller 126 may have an exit absolute Mach number of at least one, at least 1.1, at least 1.2, at least 1.3, at least 1.4, or at least 1.5. Accordingly, in such embodiments, the compressor 102 discussed herein may be “supersonic,” as the centrifugal impeller 126 may be configured to rotate about the center axis 128 at a speed sufficient to provide the process fluid at the tip 136 thereof with an exit absolute Mach number of one or greater or with a fluid velocity greater than the speed of sound. In a supersonic compressor or a stage thereof, the rotational or tip speed of the centrifugal impeller 126 may be about 500 meters per second (mis) or greater. For example, the tip speed of the centrifugal impeller 126 may be about 510 m/s, about 520 m/s, about 530 m/s, about 540 m/s, about 550 m/s, about 560 m/s, or greater.
Referring now to
The plurality of blades 144a,b may include main blades 144a spaced equidistantly apart and circumferentially about the center axis 128. Each main blade 144a may extend from a leading edge 150 disposed adjacent the first meridional end portion 132 of the centrifugal impeller 126 to a trailing edge 152 disposed adjacent the second meridional end portion 134 of the centrifugal impeller 126. Further, based on rotation of the centrifugal impeller 126, each main blade 144a may define a pressure surface on one side 154 of the main blade 144a and a suction surface on the opposing side 156 of the main blade 1144a. As shown in
The plurality of blades 144a,b may also include one or more splitter blades 144b configured to reduce aerodynamic choking conditions that may occur in the compressor 102 depending on the number of blades 144a,b employed with respect to the centrifugal impeller 126. The splitter blades 144b may be spaced equidistantly apart and circumferentially about the center axis 128. Each splitter blade 144b may extend from a leading edge 158, meridionally spaced and downstream from the first meridional end portion 132, to a trailing edge 160 disposed adjacent the second meridional end portion 134 of the centrifugal impeller 126. The leading edge 158 of each splitter blade 144b may be disposed meridionally outward from the leading edges 150 of the main blades 144a such that the respective leading edges 150, 158 of the main blades 144a and splitter blades 144b are staggered and not coplanar. Further, based on rotation of the centrifugal impeller 126, each splitter blade 144b may define a pressure surface on one side 162 of the splitter blade 144b and a suction surface on the opposing side 164 of the splitter blade 144b.
As most clearly illustrated in
The splitter blades 144b and main blades 144a may be arranged circumferentially about the center axis 128 in a pattern such that a splitter blade 144b is disposed between adjacent main blades 144a. As arranged, each splitter blade 144b may be disposed between the pressure surface side 154 of an adjacent main blade 144a and the suction surface side 156 of the other adjacent main blade 144a. Further, the splitter blades 144b may be “clocked” with respect to the main blades 144a, such that each splitter blade 144b is circumferentially offset or not equidistant from the respective adjacent main blades 144a and thus is not circumferentially centered between the adjacent main blades 144a. By clocking the splitter blades 144b, e.g., displacing the splitter blades 144b from a position equidistant from the adjacent main blades 144a, the operating characteristics of the centrifugal impeller 126 may be improved.
In one or more embodiments, the splitter blades 144b and main blades 144a may be arranged circumferentially about the center axis 128 in a pattern such that a plurality of splitter blades 144b may be disposed between adjacent main blades 144a. Accordingly, in one embodiment, at least two splitter blades 144b are disposed between adjacent main blades 144a. The leading edges 158 of the respective splitter blades 144b may be offset meridionally from one another such that the respective leading edges 158 of the splitter blades 144b are staggered and not coplanar.
As positioned between the adjacent main blades 144a, each splitter blade 144b may be oriented such that the splitter blade 144b is canted, such that the leading edge 158 of the splitter blade 144b is circumferentially offset from a position equidistant from the adjacent main blades 144a a different percentage amount than the trailing edge 160 of the splitter blade 144b. Accordingly, in an exemplary embodiment, the leading edge 158 of the splitter blade 144b may be displaced from a position equidistant from the adjacent main blades 144a by a distance of a first percentage amount of one half the angular distance θ between the adjacent main blades 144a. The trailing edge 160 of the splitter blade 144b may be displaced from the position equidistant the adjacent main blades 144a by a distance of a second percentage amount of one half the angular distance 8 between the adjacent main blades 144a.
In an exemplary embodiment, the first percentage amount may be greater than the second percentage amount. In another embodiment, the first percentage amount may be less than the second percentage amount. For example, the difference in displacement between the leading edge 158 and the trailing edge 160 from the position equidistant the adjacent main blades 144a may be a percentage amount of at least about one percent, about two percent, about three percent, about four percent, about five percent, about ten percent, about fifteen percent, or about twenty percent. In another example, the difference in displacement between the leading edge 158 and the trailing edge 160 from the position equidistant the adjacent main blades 144a may be a percentage amount of between about one percent and about two percent, about three percent and about five percent, about five percent and about ten percent, or about ten percent and about twenty percent. The differences in distance related to the percentage amounts, e.g., the amount the splitter blade 144b is canted, may be determined based, at least in part, on desired operating parameters.
As shown in
As will be appreciated by those of skill in the art, the desired displacement of the splitter blades 144b may depend on various factors, such as the shape of the blades 144a,b, the angle of incidence of the blades 144a,b, the size of the blades 144a,b and of the centrifugal impeller 126, the operating speed range, etc. However, the displacement necessary to equalize the mass flow through the first flow passage 146 and the second flow passage 148 may be determined for a given design of the centrifugal impeller 126 and corresponding blades 144a,b by measurement of the mass flow, such as by use of a mass flow meter.
As shown in
In an embodiment, illustrated most clearly in
The static diffuser 116 may be coupled with or integral with the housing 110 of the compressor 102 and may form an annular diffuser passageway 174 having an inlet end adjacent the tip 136 of the centrifugal impeller 126 and a radially outer outlet end. In an exemplary embodiment, the annular diffuser passageway 174 may be formed, at least in part, by portions of the housing 110, namely a shroud wall 180 and a hub wall 182, forming the confining sidewalls of the static diffuser 116. The shroud wall 180 and the hub wall 182 may each be a straight wall or a contoured wall, such that the annular diffuser passageway 174 may be formed from straight walls, contoured walls, or a combination thereof. In addition, the annular diffuser passageway 174 may have a reduced width as the shroud wall 180 and the hub wall 182 extend radially outward. Such a “pinched” diffuser may provide for lower choke and surge limits and, thus, improve the efficiency of the centrifugal impeller 126.
In another embodiment, the static diffuser 116 may be a vaned diffuser. Accordingly, the static diffuser 116 may have a plurality of diffuser vanes (not shown) arranged in a plurality of concentric rings (not shown) about the center axis 128 and extending from the shroud wall 180 and/or the hub wall 182 of the static diffuser 116. In an exemplary embodiment, the diffuser vanes are arranged in tandem, such that a first ring of diffuser vanes is disposed radially inward from a second ring of diffuser vanes. Respective leading edges of the diffuser vanes of the second ring may be displaced radially outward from trailing edges of the diffuser vanes of the first ring. The diffuser vanes of the first ring may have a lower solidity, or chord to pitch ratio, than the diffuser vanes of the second ring. In another embodiment, the static diffuser may include a third ring of diffuser vanes, wherein the diffuser vanes of the third ring may have a lower solidity than the diffuser vanes of the second ring. Each of the diffuser vanes may be airfoils or shaped substantially similar thereto.
A vaneless space (not shown) may be provided between the tip 136 of the centrifugal impeller 126 and the diameter formed by leading edges of the diffuser vanes of the first ring. Similarly, a vaneless space (not shown) may be provided between the diameter formed by the trailing edges of the diffuser vanes of the first ring and the leading edges of the diffuser vanes of the second ring. In one or more embodiments, the incidence of the diffuser vanes of the first ring may be determined for controlling the Mach number and reducing supersonic flow introduced at the inlet end of the static diffuser 116 to a subsonic flow at the trailing edges of the first ring. As configured, shock waves created by the leading edges of the first ring do not propagate to the diffuser vanes of the second ring; however, the leading edges of the first ring provide for a communication path from the downstream portion of the static diffuser 116 toward an upstream portion of the centrifugal impeller 126 to back pressure the centrifugal impeller 126, thereby obtaining a wider range. The incidence of the diffuser vanes of the second ring may be determined by placing the second ring in the “shadow” or flow path of the first ring. Accordingly, the diffuser vanes may be arranged such that two diffuser vanes of the second ring are provided in the wake of each diffuser vane of the first ring and are provided to alter the direction of the process fluid flow.
As discussed above, in one or more embodiments, the compressor 102 provided herein may be referred to as “supersonic” because the centrifugal impeller 126 may be designed to rotate about the center axis 128 at high speeds such that a moving process fluid encountering the inlet end 176 of the static diffuser 116 is said to have a fluid velocity which is above the speed of sound of the process fluid being compressed. Thus, in an exemplary embodiment, the moving process fluid encountering the inlet end 176 of the static diffuser 116 may have an exit absolute Mach number of about one or greater. However, to increase total energy of the fluid system, the moving process fluid encountering the inlet end 176 of the static diffuser 116 may have an exit absolute Mach number of at least about 1.1, at least about 1.2, at least about 1.3, at least about 1.4, or at least about 1.5. In another example, the process fluid at the tip 136 of the centrifugal impeller 126 may have an exit absolute Mach number from about 1.1 to about 1.5, or about 1.2 to about 1.4.
The process fluid flow leaving the outlet end of the static diffuser 116 may flow into the collector 117, as most clearly seen in
One or more exemplary operational aspects of the compression system 100 will now be discussed with continued reference to
The process fluid may be drawn into the rotating centrifugal impeller 126 and may contact the curved centrifugal impeller blades 144a,b, such that the process fluid may be accelerated in a tangential and radial direction by centrifugal force through the first flow passages 146 and the second flow passages 148 and may be discharged from the blade tips of the centrifugal impeller 126 (cumulatively, the tip 136 of the centrifugal impeller 126) in at least partially radial directions that extend 360 degrees around the rotating centrifugal impeller 126. The rotating centrifugal impeller 126 increases the velocity and static pressure of the process fluid, such that the velocity of the process fluid discharged from the blade tips (cumulatively, the tip 136 of the centrifugal impeller 126) may be supersonic in some embodiments and have an exit absolute Mach number of at least about one, at least about 1.1, at least about 1.2, at least about 1.3, at least about 1.4, or at least about 1.5.
The static diffuser 116 may be disposed circumferentially about the periphery, or tip 136, of the centrifugal impeller 126 and may be coupled with or integral with the housing 110 of the compressor 102. The radial process fluid flow discharged from the rotating centrifugal impeller 126 may be received by the static diffuser 116 such that the velocity of the flow of process fluid discharged from the tip 136 of the rotating centrifugal impeller 126 is substantially similar to the velocity of the process fluid entering the inlet end of the static diffuser 116. Accordingly, the process fluid may enter the inlet end of the static diffuser 116 with a supersonic velocity having, for example, an exit absolute Mach number of at least one, and correspondingly, may be referred to as supersonic process fluid.
The velocity of the supersonic process fluid flowing into the inlet end of the static diffuser 116 decreases with increasing radius of the annular diffuser passageway 174 as the process fluid flows from the inlet end to the radially outer outlet end of the static diffuser 116 as the velocity head is converted to static pressure. In some embodiments, the tangential velocity of the supersonic process fluid may decelerate from supersonic to subsonic velocities across the diffuser vanes of the first ring without shock losses. Accordingly, the static diffuser 116 may reduce the velocity and increase the pressure energy of the process fluid.
The process fluid exiting the static diffuser 116 may have a subsonic velocity and may be fed into the collector 117 or discharge volute. The collector 117 may increase the static pressure of the process fluid by converting the remaining kinetic energy of the process fluid to static pressure. The process fluid may then be routed to perform work or for operation of one or more downstream processes or components (not shown).
The process fluid pressurized, circulated, contained, or otherwise utilized in the compression system 100 may be a fluid in a liquid phase, a gas phase, a supercritical state, a subcritical state, or any combination thereof. The process fluid may be a mixture, or process fluid mixture. The process fluid may include one or more high molecular weight process fluids, one or more low molecular weight process fluids, or any mixture or combination thereof. As used herein, the term “high molecular weight process fluids” refers to process fluids having a molecular weight of about 30 grams per mole (g/mol) or greater. Illustrative high molecular weight process fluids may include, but are not limited to, hydrocarbons, such as ethane, propane, butanes, pentanes, and hexanes. Illustrative high molecular weight process fluids may also include, but are not limited to, carbon dioxide (CO2) or process fluid mixtures containing carbon dioxide. As used herein, the term “low molecular weight process fluids” refers to process fluids having a molecular weight less than about 30 g/mol. Illustrative low molecular weight process fluids may include, but are not limited to, air, hydrogen, methane, or any combination or mixtures thereof.
In an exemplary embodiment, the process fluid or the process fluid mixture may be or include carbon dioxide. The amount of carbon dioxide in the process fluid or the process fluid mixture may be at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or greater by volume. Utilizing carbon dioxide as the process fluid or as a component or part of the process fluid mixture in the compression system 100 may provide one or more advantages. For example, the high density and high heat capacity or volumetric heat capacity of carbon dioxide with respect to other process fluids may make carbon dioxide more “energy dense.” Accordingly, a relative size of the compression system 100 and/or the components thereof may be reduced without reducing the performance of the compression system 100.
The carbon dioxide may be of any particular type, source, purity, or grade. For example, industrial grade carbon dioxide may be utilized as the process fluid without departing from the scope of the disclosure. Further, as previously discussed, the process fluids may be a mixture, or process fluid mixture. The process fluid mixture may be selected for one or more desirable properties of the process fluid mixture within the compression system 100. For example, the process fluid mixture may include a mixture of a liquid absorbent and carbon dioxide (or a process fluid containing carbon dioxide) that may enable the process fluid mixture to be compressed to a relatively higher pressure with less energy input than compressing carbon dioxide (or a process fluid containing carbon dioxide) alone.
It should be appreciated that all numerical values and ranges disclosed herein are approximate valves and ranges, whether “about” is used in conjunction therewith. It should also be appreciated that the term “about,” as used herein, in conjunction with a numeral refers to a value that is +/−5% (inclusive) of that numeral, +/−10% (inclusive) of that numeral, or +/−15% (inclusive) of that numeral. It should further be appreciated that when a numerical range is disclosed herein, any numerical value falling within the range is also specifically disclosed.
Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and/or the combination of any two upper values are contemplated unless otherwise indicated.
The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.
This application claims the benefit of U.S. Provisional Patent Application having Ser. No. 62/139,032, which was filed Mar. 27, 2015. The aforementioned patent application is hereby incorporated by reference in its entirety into the present application to the extent consistent with the present application.
This invention was made with government support under Government Contract No. DOE-DE-FE0000493 awarded by the U.S. Department of Energy. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62139032 | Mar 2015 | US |
