JP2016514789A - Method and system for controlling a turbo compressor - Google Patents

Abstract

A method for adjusting the turbo compressor to prevent surge will be described. The method includes providing at least one surge limit line (SLL) of the turbo compressor 21; continuously determining an actual value of the correction speed (Nc) of the turbo compressor 21; Corresponding to the actual value, at least the maximum allowable pressure ratio (PRmax) on the surge limit line is continuously determined, the actual pressure ratio (PR) is continuously determined, and the actual pressure ratio is Activating an anti-surge configuration when greater than a maximum allowable pressure ratio. [Selection] Figure 5

Description

  The present disclosure relates to compressor systems, and more particularly to turbo compressor systems that include axial and / or centrifugal compressors for processing gas streams. The subject matter of this disclosure relates specifically to methods and systems for controlling compressor equipment to prevent phenomena outside the operating envelope, such as surges and other undesirable operating conditions.

  A turbo compressor is a working absorption turbomachine used to raise the pressure of a working gas stream. The pressure of the working fluid adds kinetic energy to the continuous flow of working fluid by rotation of the rotor supporting one or more impellers and / or one or more sets of blades arranged in an annulus. Increase by. In gas and oil applications, cooling systems, gas turbines, and other applications, turbo compressors are frequently used in pipeline transportation of natural gas, for example, to send gas from a production site to a consumer location.

  The fluid flow through the turbocompressor can be affected by various conditions, which results in unstable operation that can lead to serious damage to the turbomachine.

  A compressor surge occurs when the pressure of the working fluid flowing through the compressor becomes higher than the maximum allowable output pressure and / or when the flow rate drops below a minimum.

  In general, surge phenomena occur when the compressor is unable to apply sufficient energy to the working fluid to overcome system resistance, a situation that results in a system-wide drop, rapid flow and reduced discharge pressure. Surges can be accompanied by high vibrations, temperature increases and sudden changes in the axial thrust of the compressor bearing. These phenomena can severely damage the compressor and system components connected to the compressor, such as valves and piping.

  Other undesirable operating conditions can occur during operation of the turbo compressor. More specifically, choke (also called a stone wall) is a condition that causes a rapid decrease of the head, that is, a decrease in the compression ratio. Operation at very high flow rates can adversely affect compressor performance and cause compressor damage. In order to prevent the occurrence of surges and chokes, control systems have been developed and are currently used in turbo compressor installations.

  FIG. 1 schematically shows an exemplary embodiment of a system 1, which includes a main prime mover 5, such as a turbo compressor 3 that is rotationally driven by an electric motor, a gas or steam turbine, and the like. Reference numeral 7 denotes a suction line from which a working fluid is supplied to the suction side, that is, the inlet side of the turbo compressor 3. Reference numeral 9 denotes a discharge pipe through which compressed fluid is discharged from the discharge side of the compressor 3.

  FIG. 2 schematically shows a compressor performance map, typically a compressor performance map for an axial compressor. The performance map shows the pressure ratio on the vertical axis and the inlet volume flow on the horizontal axis. The inlet flow rate is indicated by the letter Q. A plurality of expected performance curves can be recorded in the performance map depending on the operating conditions of the compressor, such as the rotational speed (rpm). Each curve can correspond to a different compressor rotational speed. Thus, for a given compressor setting, a family of performance curves can be recorded on the performance map. Similar curve families can be drawn for various settings or operating conditions of the turbocompressor, for example for various positions of the variable stator vane (VSV) that can be provided to the turbocompressor. Each performance curve is limited by the surge point, i.e. the pressure ratio and the point at which the gas flow through the compressor reaches a certain value, beyond which the surge phenomenon occurs. Each performance curve is further limited by the choke point above which the choke phenomenon occurs. The line SLL is a so-called surge limit line and is formed by surge points of various performance curves recorded in the performance map. Line CLL is a choke limit line and is formed by choke points. The SLL and CLL lines define the envelope, or part of the performance map, within which the compressor's compressor is designed to ensure stable operating conditions and prevent both surge and choke conditions. The operating point must be maintained.

  Thus, SLL and CLL indicate the limits of turbo compressor operation, and in order to prevent the risk of surge and choke phenomena, do not operate the turbo compressor beyond that. Known compressor systems are equipped with a control device and configuration for controlling a turbo compressor and always operate within the stability region of the performance map, ie between the surge limit line SLL and the choke limit line CLL.

  In the schematic diagram of FIG. 1, the controller 11 surrounds the turbo compressor to determine the operating conditions of the turbomachine and to provide antisurge and antichoke control to prevent the occurrence of surge and choke phenomena. Connected to various means.

  More specifically, as shown in FIG. 1, the control unit 11 is connected to a flow rate measuring device also called a flow element 13, and the flow element 13 is designed to determine the inlet volume flow rate of the turbo compressor 3. It is configured. The inlet or suction side temperature sensor provides the temperature Ts, and the pressure sensor provides the discharge pressure value Pd and the suction pressure value Ps, or directly provides the compression ratio Pd / Ps.

  Based on the input data, the control unit 11 can determine the inlet volume flow rate and the pressure ratio at any time during the operation of the turbo compressor 3. These two parameters define the operating point on the compressor performance map of FIG. Since the compressor rotational speed N (rpm) can be provided as an additional parameter, an accurate operating curve can be selected to determine the actual position of the compressor operating point in the performance map. When the operating point moves and approaches the surge limit line SLL, the surge control system activates the anti-surge bypass valve 15. The valve 15 is disposed on a bypass line 17 that connects the discharge side and the suction side of the compressor 3. A part of the working fluid discharged from the turbo compressor 3 is recirculated through the antisurge valve 15 to prevent a surge phenomenon, if necessary. When the discharge pressure increases and the operating point approaches the surge limit line SLL, the anti-surge control device can open the anti-surge bypass valve 15 to increase the flow rate through the compressor and decrease the discharge pressure. .

  Prior to recirculation through the anti-surge valve 15, the working fluid can be cooled with a heat exchanger 19.

  In some embodiments, the surge control configuration can be provided with a bleed line along with an anti-surge valve positioned and designed to release process gas to the environment if the nature of the gas allows. The

  By closing the anti-choke control valve disposed along the suction line 7 or upstream or downstream of the discharge line of the turbo compressor 3, choke of the compressor can be prevented.

  The actual known solution requires a flow element 13 for determining the operating point of the compressor in order to prevent surge phenomena. In some applications, the flow element 13 is cumbersome and requires relatively long pipes upstream and downstream to provide an accurate measurement of inlet flow. Providing measuring elements or devices on the inlet side or the suction side of the turbocompressor can be difficult, especially with air turbocompressors.

US Patent Application Publication No. 2007/095063

  The subject matter disclosed herein relates to an improved method and apparatus for providing anti-surge control of a compression system that includes at least one compressor. In some embodiments, the method and apparatus provide compressor anti-surge and / or anti-choke control.

  In some embodiments, at least one operating envelope is defined and controlled so that the operating point of the compressor falls within the operating envelope. An operation is performed when the operating point is outside or at the boundary of the operating envelope, or when the operating point approaches the boundary of the envelope. The operating envelope is defined based on a performance map based on two compressor operating parameters, namely the compressor correction speed and pressure ratio. The pressure ratio is a ratio between the discharge pressure and the suction pressure of the compressor. The correction speed is defined as a function of the suction temperature of the gas being processed by the compressor and the rotational speed of the compressor. Therefore, the correction speed is proportional to the following ratio:

here,
Ts is the process fluid temperature at the compressor inlet,
N is the rotational speed of the compressor.

  If the gas composition is constant, the correction speed is defined by the ratio described above. Accordingly, the method disclosed herein is suitable for anti-surge / anti-choke control of a compressor that processes a gas having a known and constant composition, such as carbon dioxide.

  The operating envelope can be bounded by a suction limit line, a choke limit line, and a maximum allowable correction speed and a minimum allowable correction speed.

  When a movable inlet guide vane, that is, a variable vane is provided in the compressor, an operation envelope can be defined for each position of the variable vane. Thus, according to some, a plurality of motion envelopes are defined in a corrected speed versus compression ratio diagram or performance map. Depending on the actual position of the variable vane, a corresponding operating envelope is selected for anti-surge and / or anti-choke control. Since the position of the variable vane can typically vary continuously, according to some embodiments, a limited number of operating envelopes are determined, which are limited for different positions of the variable vane. It corresponds to the number. If the actual position of the variable vane is different from the one for which the envelope was determined and the corresponding data stored for control purposes, the new intermediate motion envelope is the two most available data. It is calculated by interpolating the data of the near motion envelope.

Thus, according to some embodiments, a method for adjusting a turbo compressor to prevent surges is provided, the method comprising:
Providing at least one surge limit line and / or at least one choke line for at least one operating condition of the turbo compressor;
Continuously determining the operating point of the compressor, measuring the process gas temperature at the compressor inlet, the rotational speed of the compressor, and the discharge pressure value and the suction pressure value;
ratio

Continuously determining the actual value of the turbo compressor correction speed, which is a correction speed proportional to
Continuously determining at least the maximum allowable pressure ratio on the surge limit line and / or at least the minimum allowable pressure ratio on the choke line, corresponding to the actual value of the correction speed;
Continuously determining an actual pressure ratio equal to the ratio of the discharge pressure and the suction pressure;
If the actual pressure ratio is above the maximum allowable pressure ratio or below the minimum allowable pressure ratio, activate the anti-surge configuration to recirculate some of the compressor's compressed gas through the suction line Steps.

  In the context of the present disclosure and the appended claims, the term “determining the parameters continuously” includes determining the parameters at constant or variable time intervals during the continuous operation of the compressor.

  In a preferred embodiment, the surge limit line defines an operating envelope along with the choke limit line and the maximum and minimum allowable correction speed lines, and the operating point of the compressor must be maintained within that range.

  When the operating point of the compressor is approaching the surge limit line, the anti-surge configuration can be activated. The anti-surge configuration can be any configuration known in the prior art. Surge is prevented by opening the anti-surge bypass valve. In certain embodiments, when the process gas is air, surge can be prevented by exhausting or bleeding a portion of the compressor discharge flow rate in the environment. In either case, the operating point of the compressor is shifted away from the surge limit line by increasing the discharge flow rate.

  The method can also include a preceding step of detecting the type or composition of gas entering the turbocompressor.

  Since the exact rate is related to the gas composition or type, gas detection or prediction allows on-line continuous setting of the method.

  In particular, if the working gas has a composition that is not constant over time, the method requires information about the gas operated by the turbocompressor. To obtain this information, any gas detector known in the art, such as a process gas chromatograph, can be used.

  The apparatus also includes a suitable database for storing operating envelopes associated with each gas.

  When the operating point of the compressor approaches the upper correction speed limit or the lower correction speed limit, the operation is performed to decrease or increase the rotation speed of the compressor, respectively.

  When the compressor operating point is approaching the choke limit line, the anti-choke arrangement can be activated. The configuration can be any configuration known in the art. For example, the anti-choke valve can be closed.

  In some embodiments, a variable vane or movable inlet guide vane can be provided on the suction side of the compressor. The variable vane can be used as a control means to prevent the operating point of the compressor from approaching or moving beyond the line that delimits the operating envelope. Choke can be prevented, for example, by reducing the inlet cross-sectional area and reducing the inlet flow rate of the compressed gas.

  The variable vane can also be actuated to prevent the compressor operating point from moving above the upper corrected speed limit or falling below the lower corrected speed limit.

  According to a further aspect, the subject matter disclosed herein relates to an apparatus for providing anti-surge and / or anti-choke control for a compression system that includes at least one compressor, said apparatus comprising: The above control method is executed. According to yet another aspect, the subject matter disclosed herein relates to a compression system that includes at least one compressor and the apparatus for anti-surge and / or anti-choke control.

According to a further aspect, the subject matter disclosed herein relates to a method for adjusting a turbo compressor, the method comprising:
At least one compressor operating envelope on a corrected speed to pressure ratio diagram or performance map, which can be bounded by a choke limit line, a surge limit line, a maximum allowable correction speed line, and a minimum allowable correction speed line Determining an operating envelope;
Continuously determining the operating point of the turbo compressor on the corrected speed to pressure ratio diagram;
Determining whether the operating point is included in the operating envelope;
Activating an operating system to change at least one operating parameter of the turbo compressor if the operating point of the turbo compressor is not within the operating envelope. The method is particularly suitable for polluted gases because it can prevent the diffusion of gases into the environment.

  The features and embodiments are disclosed below and are further described in the appended claims and form an integral part of the specification. The brief description above sets forth features of various embodiments of the invention so that the detailed description that follows may be better understood, and so that the contribution of the invention to the art may be better appreciated. doing. There are, of course, other features of the invention that will be described hereinafter and which will be set forth in the appended claims. In this regard, before describing some embodiments of the present invention in detail, the various embodiments of the present invention, in their application, will be described in detail in the following description or shown in the drawings with structural details and components. It should be understood that the present invention is not limited to this arrangement. The invention is capable of other embodiments and of being practiced and carried out in various ways. It should also be understood that the expressions and terms used herein are for purposes of illustration and should not be considered limiting.

  As such, one of ordinary skill in the art can readily utilize the concepts underlying this disclosure as a basis for designing other structures, methods, and / or systems to accomplish some objectives of the present invention. You will understand what you can do. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

  A more complete evaluation of the disclosed embodiments of the present invention and many of the attendant advantages of the present invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

It is a figure which shows the outline of the compressor system by a prior art. FIG. 3 shows a compressor performance map currently used in anti-surge and anti-choke control systems. 1 is a schematic diagram of a compressor system according to the present invention. FIG. 4 is a schematic view similar to FIG. 3 of a system including a turbo compressor having moveable variable vanes. FIG. 3 shows a compressor performance map according to the present invention showing one operating envelope. FIG. 6 is a compressor performance map showing two overlapping envelopes corresponding to two different positions of a movable inlet guide vane or variable vane of a turbo compressor. 6 is a flowchart summarizing a control algorithm according to the present disclosure.

  The following detailed description of exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Further, the drawings are not necessarily drawn to scale. Also, the following detailed description does not limit the invention. Rather, the scope of the invention is defined by the appended claims.

  Throughout the specification, references to “one embodiment” or “an embodiment” or “some embodiments” refer to at least a particular feature, structure, or characteristic disclosed in connection with the embodiment. It is meant to be included in one embodiment. Thus, the phrases “in one embodiment” or “in one embodiment” or “in some embodiments” appearing in various places throughout this specification are not necessarily referring to the same embodiment. . Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

  FIG. 3 schematically illustrates a compressor system 20 that embodies the subject matter disclosed herein. The compressor system 20 includes a turbo compressor 21, such as a centrifugal or axial flow turbo compressor. The turbo compressor 21 can be rotationally driven by a prime mover 23. In some embodiments, prime mover 23 may be an electric motor. In other embodiments, prime mover 23 may be a gas turbine, such as an aeroderivative gas turbine. In further embodiments, a different main prime mover, such as a steam turbine, may be used. The load coupling 26 connects the main prime mover 23 to the turbo compressor 21. A speed operating device (not shown), for example a gearbox, can be arranged between the main prime mover 23 and the turbo compressor 21.

  The working gas is supplied to the inlet side of the turbo compressor 21 through the suction line 25, that is, the suction side, and the compressed fluid is discharged from the discharge side of the compressor through the discharge line or pressure line 27. The check or check valves 29A, 29B can be arranged in the suction line and / or the pressure line 27.

  The heat exchanger 31 can be arranged on the pressure line 27 or along a bypass line 33 connecting the pressure line 27 to the suction line 25 as indicated by reference numeral 31x. The antisurge bypass valve 35 is disposed along the bypass line 33. Anti-surge valve 35 is controlled by an anti-surge control system 37 which will be described in more detail below.

  In certain embodiments, for example when the working fluid is a fluid that can be exhausted to the air or the environment, the working fluid is exhausted directly into the atmosphere even though some is recirculated through the suction line 25. The antisurge valve 35 can be arranged on the bleed line to be performed.

  In order to detect the working gas entering the turbocompressor, the system can comprise a configuration 50 for detecting the composition or type of gas. This configuration may be a specific type of gas chromatograph.

  The system 20 is further provided with a control unit 39. The control unit 39 is connected to the temperature sensor 41 on the inlet side of the turbo compressor 21, that is, the suction side, and the pressure sensor. The pressure sensor directly or indirectly provides a measurement of the pressure ratio between the discharge side and the suction side of the compressor. As an example, in the schematic diagram of FIG. 3, the discharge side pressure sensor 43 provides a discharge pressure value Pd on the discharge side of the turbo compressor 21. The pressure sensor 45 at the inlet of the turbo compressor 21 provides a measurement of the suction pressure Ps at the inlet of the turbo compressor 21. The pressure ratio can be calculated by the control unit 39 based on the two measured pressure values Pd and Ps. In another embodiment, the pressure ratio can be determined outside the control unit 39, and the pressure ratio value can be input directly to the control unit 39.

  The rotation speed sensor further provides the control unit 39 with a rotation speed N (for example, expressed in rpm).

  Based on the operation parameters described above, the control unit 39 can calculate a pressure ratio of the compressor and a so-called compressor correction speed defined as follows.

here,
C1 is a function of temperature, pressure and gas composition;
N is the rotational speed of the turbo compressor 21;
Ts is the absolute temperature of the suction of the turbo compressor 21.

  The coefficient C1 is a function of the gas composition and is assumed to be constant if the gas has a constant composition and T and P are in a limited range.

  For gases that are known and have a constant composition, the correction rate can be simplified as follows.

The corrected speed can be used to define the compressor performance map, the corrected speed is recorded in one of the coordinates, and the pressure ratio is recorded in the other coordinates.

  FIG. 5 schematically shows this type of performance map, with the correction speed recorded on the vertical axis and the pressure ratio Pd / Ps recorded on the horizontal axis. A surge limit line SLL can be drawn on this performance map. To prevent the surge phenomenon, the compressor 21 operates such that the operating point on the performance map of FIG. 5 stays on the left side of the surge control line, so that the compressor is on the surge limit line SLL or Don't work beyond that.

  On the same performance map of FIG. 5, a choke limit line CLL can also be drawn, indicating the limit at which the choke phenomenon may occur. In order to operate the compressor 21 so as not to cause choke, the operating point of the compressor is prevented from moving to the left beyond the choke limit line CLL.

  Two more lines are drawn on the performance map of FIG. 5, that is, the minimum allowable correction speed line (Nc) min and the maximum allowable correction speed line (Nc) max. The latter is a straight line parallel to the horizontal coordinate (horizontal axis), below which the minimum allowable correction speed at which the compressor should not operate and the maximum correction speed at which the turbo compressor should not operate above that, respectively. Represents.

  The four lines defined above form the operating envelope OE. The compressor control system controls the compressor so that the operating point stays inside the operating envelope OE. FIG. 5 shows an exemplary operating point labeled OP, which corresponds to the corrected speed value Nc and the pressure ratio PR = Pd / Ps.

  When the point OP moves to the right and reaches the surge limit line SLL, the operating condition of the turbo compressor 21 is changed and the control system is designed and arranged to return the operating point OP into the operating envelope OE. ing. This can be obtained, for example, by opening the antisurge valve 35. When the operating point OP moves to the left until it reaches the choke limit line CLL, the control system operates to change the flow conditions and return the operating point to the inside of the operating envelope OE. This can be done, for example, by actuating the anti-choke valve 47.

  When the operating point OP moves downward and reaches the minimum allowable correction speed value (Nc) min line, the rotational speed of the compressor 21 is increased to lower the minimum allowable correction speed value (Nc) min. It is prevented from moving. Movement of the operating point exceeding the maximum allowable correction speed value (Nc) max is prevented by decreasing the rotational speed of the turbo compressor 21 accordingly.

  In the simplified schematic diagram of FIG. 3, the turbocompressor 21 does not include a movable inlet guide vane or variable stator vane (VSV). These latter are usually provided in general turbo compressors in order to change the geometry of the inlet cross section according to the operating conditions of the system. FIG. 4 shows the same system as FIG. 3, but with the addition of a variable vane schematically shown at 51. The same reference numerals as in FIG. 3 denote the same or corresponding components or parts, which will not be described again. In the system of FIG. 4, the control unit 39 further receives information on the actual position of the variable stationary blade of the turbo compressor 21. The symbol VSV indicates information regarding the actual position of the variable stationary blade during operation of the turbo compressor 21. The position of VSV can be set by an appropriate actuator not shown. The actuator can be controlled by the same control unit 39.

  The anti-choke valve 47 is omitted from the schematic diagram of FIG. 4 because chokeing can be prevented by operating the VSV instead. To avoid compressor choking without necessarily using an anti-choke valve, the latter is closed to reduce the inlet volume flow of the turbo compressor.

  In practice, different performance maps and thus different motion envelopes can be drawn for each possible position of the movable variable vane 51. This is shown schematically in FIG. 6 and shows two different operating envelopes labeled OE1 and OE2. Each motion envelope is surrounded by four curves defined for both cases, similar to that described above in connection with FIG. Therefore, each operation envelope is surrounded by a surge limit line SLL, a choke limit line CLL, a maximum allowable correction speed line (Nc) max, and a minimum allowable correction speed line (Nc) min.

  In fact, an unspecified number of operating envelopes can be provided, one for each variable vane position. Data defining each operation envelope is stored in a memory that can be accessed by the control unit 39, and is schematically indicated by reference numeral 38 in FIGS. In a practical embodiment, a finite number of motion envelopes are calculated and stored in the form of a look-up table, for example. When there is an operation envelope corresponding to the actual position of the variable stationary blade during the operation of the turbo compressor 21, the control unit 39 uses such an envelope. If the actual position of the variable vane is different from the one in which the operating envelope is stored in the control system, the control unit may, for example, place the operating envelope in the two closest VSV positions available in the storage memory. The motion envelope is calculated by interpolating existing data using the corresponding data.

  The operation of the system described so far will become more apparent from the following description with reference to the above drawing and with reference to the flowchart of FIG. In the latter, the control process is shown as a series of steps. It will be appreciated that the series of method steps shown in FIG. 7 is repeated continuously and repeatedly during operation of the system to obtain continuous control of the operating conditions of the compressor 21.

  When the control process is started, the correction speed Nc is determined. This is performed by detecting the rotational speed N of the turbo compressor 21 and the temperature Ts on the suction side. As described with reference to FIG. 4, when the variable stator blade 51 is provided in the turbo compressor 21, the position of the VSV is determined. Based on the data regarding the actual position of the variable stator blade, for example, using the data stored in the storage memory 38, the operation envelope is calculated. As described above, the operating envelope data can be stored directly in the storage memory 38 for some of the variable vane positions. For other intermediate positions, for example, an operation envelope can be calculated by interpolating existing data.

  Once the operating envelope is determined, the maximum and minimum pressure ratios for the actual corrected speed Nc can be determined. The maximum ratio and the minimum ratio are indicated by PRmax and PRmin in FIG.

  Then, the actual operating point of the compressor includes the correction speed Nc calculated as described above, the actual pressure ratio determined by the pressure sensor that measures the discharge pressure Pd and the suction pressure Ps of the turbo compressor 21, and To be determined. The actual pressure ratio is indicated by PR in FIG.

  At this point, the control system has all the data necessary to operate the anti-surge and / or anti-choke arrangement to prevent system chokes and surges. In some embodiments, the surge and choke parameters can be calculated as follows. Surge parameters are defined as follows:

here,
PRmax is the maximum allowable pressure ratio,
PR is the actual pressure ratio.

  The choke parameters can be defined as follows:

here,
PRmin is the minimum allowable pressure ratio.

  The surge and choke parameters can be used to generate a control signal that activates an actuator that controls the anti-surge valve 35 and anti-choke valve 47 and / or VSV 51. If the surge parameter is equal to 1, that is, if the operating point of the compressor has moved onto the surge control line, the actuator of the anti-surge valve 35 will at least partially open the anti-surge valve 35 on the bypass line 33. Operates on. The working gas is recirculated from the discharge side of the compressor to the suction side to return the operating point OP into the operating envelope OE. When the choke parameter is equal to 1, the anti-choke valve 47 on the suction line 25 is partially closed to reduce the suction flow rate and return the compressor operating point to the inside of the operating envelope OE.

  The correction of the actual correction speed value Nc and the rotational speed N of the turbo compressor 21 known by the control system is caused by the correction speed decreasing below the minimum allowable value (Nc) min or the maximum allowable value (Nc) max. This can be done as needed to prevent further increase. In some embodiments, if the corrected speed value Nc falls below a minimum value or rises above a maximum allowable value, the turbo compressor is moved to a different operating point with a different operating envelope. In addition, the position of the VSV can be changed.

  Although disclosed embodiments of the subject matter described in this specification are illustrated in the drawings and have been fully described above with specific details in connection with certain exemplary embodiments, the novel teachings, It will be apparent to those skilled in the art that many modifications, variations, and omissions can be made without departing substantially from the principles and concepts described in the document and the advantages of the claimed subject matter. It will be clear. Accordingly, the proper scope of the disclosed invention should be determined only by the broadest interpretation of the appended claims, including all such modifications, changes and omissions. Further, the order or sequence of any process or method steps can be changed or reordered according to alternative embodiments.

1 System 3 Turbo Compressor 5 Main Motor 7 Suction Line 9 Discharge Pipe 11 Control Unit 13 Flow Element 15 Anti-Surge Bypass Valve 17 Bypass Line 19 Heat Exchanger 20 Compressor System 21 Turbo Compressor 23 Motor 25 Suction Line 26 Load Coupling 27 Pressure line 29A, 29B Check valve 31 Heat exchanger 33 Bypass line 35 Anti-surge bypass valve 37 Anti-surge control system 38 Storage memory 39 Control unit 41 Temperature sensor 43 Pressure sensor 45 Pressure sensor 47 Anti-choke valve 50 Configuration 51 Variable stationary blade (VSV)
CLL Choke limit line N Rotational speed Nc Correction speed OE Operating envelope OP Operating point PR Pressure ratio Pd Discharge pressure Ps Suction pressure SLL Surge limit line

Claims (15)

A method of adjusting a turbo compressor (21) to prevent surges, comprising:
Providing at least one surge limit line (SLL) and / or at least one choke line (CLL) of the turbo compressor (21);
The operating point of the compressor (21) for measuring the processing gas temperature (Ts) at the compressor inlet, the rotational speed (N) of the compressor (21), and the discharge pressure value and the suction pressure value (Pd, Ps). Continuously determining
ratio
Continuously determining the actual value of the correction speed (Nc) of the turbo compressor (21), which is a correction speed (Nc) proportional to
At least a maximum allowable pressure ratio (PRmax) on the surge limit line (SLL) and / or at least a minimum allowable pressure ratio (PRmin) on the choke line (CLL) corresponding to the actual value of the correction speed (Nc). ) Continuously determining,
Continuously determining an actual pressure ratio (PR) equal to the ratio of discharge pressure to suction pressure (Pd / Ps);
When the actual pressure ratio (PR) is equal to or greater than the maximum allowable pressure ratio (PRmax) or equal to or less than the minimum allowable pressure ratio (PRmin), the compressor (21) is passed through a suction line (25). Activating an anti-surge arrangement (35) to recirculate a portion of the compressed gas. Further comprising the step of calculating a surge parameter defined by:
here,
PRmax is the maximum allowable pressure ratio,
PR is the actual pressure ratio,
The method of claim 1, wherein the surge parameter is used to control the anti-surge configuration (35). Further comprising calculating a choke parameter defined by:
here,
PRmin is the minimum allowable pressure ratio,
PR is the actual pressure ratio,
The method of claim 1 or 2, wherein the choke parameter is used to control an anti-choke configuration. Providing at least one maximum allowable correction speed (Ncmax) and at least one minimum allowable correction speed (Ncmin) of the turbocompressor (21);
Decreasing the rotational speed (N) of the compressor (21) if the actual value of the correction speed (Nc) is higher than the maximum allowable correction speed (Ncmax);
Increasing the rotational speed (N) of the compressor (21) if the actual value of the correction speed (Nc) is lower than the minimum allowable correction speed (Ncmin). Item 4. The method according to any one of Items 1 to 3. Providing a variable stator vane (51) at the inlet of the turbo compressor (21);
Determining a parameter representing the position of the variable vane (VSV) (51);
Among a plurality of surge limit lines (SLL) and / or a plurality of choke lines (CLL), each corresponding to a respective position of the variable stator vane (51), the surge limit line (SLL) as a function of the parameter. And / or selecting the choke line (CLL). Setting a maximum allowable correction speed (Ncmax) and a minimum allowable correction speed (Ncmin) corresponding to the position of the variable vane (VSV) (51);
When the actual value of the correction speed (Nc) is higher than the maximum allowable correction speed (Ncmax), or when the actual value of the correction speed (Nc) is lower than the minimum allowable correction speed (Ncmin) Activating the variable stator vane (51). 6. The method according to any one of claims 1 to 5, further comprising:   The method according to any one of the preceding claims, further comprising the preceding step of detecting the type of gas entering the turbocompressor (21).   Apparatus for providing anti-surge control for a compression system comprising at least one compressor (21), arranged and configured to carry out the method according to any one of claims 1-7. apparatus. A device (37) for providing antisurge control for a compression system comprising at least one compressor (21), said device (37) comprising:
A data storage device (38) for storing data defining at least one surge limit line (SLL) and / or at least one choke line (CLL) of the turbo compressor (21);
A configuration for continuously determining the operating point of the compressor (21), a temperature sensor (41) for measuring a processing gas temperature (Ts) at the compressor inlet, and the compressor (21) A configuration including a rotation speed sensor for measuring the rotation speed (N) and a pressure sensor (43, 45) for measuring the discharge pressure value and the suction pressure value (Pd, Ps);
ratio
A configuration for continuously determining the actual value of the correction speed (Nc) of the turbo compressor (21), which is a correction speed (Nc) proportional to
At least a maximum allowable pressure ratio (PRmax) on the surge limit line (SLL) and / or at least a minimum allowable pressure ratio (PRmin) on the choke line (CLL) corresponding to the actual value of the correction speed (Nc). ) To determine continuously,
A configuration for continuously determining an actual pressure ratio (PR) equal to the ratio of discharge pressure to suction pressure (Pd / Ps);
An antisurge configuration (35) for recirculating a portion of the compressed gas of the compressor (21) through a suction line (25), wherein the actual pressure ratio (PR) is the maximum allowable pressure ratio ( An anti-surge configuration (35) that operates when greater than or equal to PRmax) or less than the minimum allowable pressure ratio (PRmin). Further comprising a device for calculating a surge parameter defined by
here,
PRmax is the maximum allowable pressure ratio,
The apparatus (37) of claim 9, wherein PR is the actual pressure ratio. Further comprising a device for calculating a choke parameter defined by:
here,
PRmin is the minimum allowable pressure ratio,
11. Apparatus (37) according to claim 9 or claim 10, wherein PR is the actual pressure ratio.   The storage device (38) stores data defining at least one maximum allowable correction speed (Ncmax) and at least one minimum allowable correction speed (Ncmin) of the compressor (21), and is provided with a speed control device. The speed control device reduces the rotational speed (N) of the compressor (21) when the actual value of the correction speed (Nc) is higher than the maximum allowable correction speed (Ncmax). When the actual value of the correction speed (Nc) is lower than the minimum allowable correction speed (Ncmin), the rotation of the compressor is increased so that the rotation speed (N) of the compressor (21) increases. Device (37) according to any one of claims 9 to 11, which controls the speed (N).   It further includes an actuating device for controlling the position of the variable stator blade (51) of the compressor (21), and the storage device (38) corresponds to a plurality of positions of the variable stator blade (51). Device (37) according to any one of claims 9 to 12, storing data defining a plurality of surge limit lines (SLL) and / or choke lines (CLL).   14. A device (37) according to one or more of claims 9 to 13, for a compression system comprising at least one compressor (21) and for anti-surge control of the compressor (21).   The compression system of claim 14, further comprising a configuration (50) for detecting the type of gas entering the turbocompressor (21).