KR20150134397A - Methods and systems for controlling turbocompressors - Google Patents

Abstract

A method of controlling a turbo compressor to prevent surge is 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; Continuously determining at least the usable maximum pressure ratio PRmax on the surge limit line, corresponding to the actual value of the correction speed; Continuously determining an actual pressure ratio PR; And operating the surge protector if the actual pressure ratio is greater than an allowable maximum pressure ratio.

Description

[0001] METHODS AND SYSTEMS FOR CONTROLLING TURBOCOMPRESSORS [0002]

The present disclosure relates to a compressor system, and more particularly to a turbocompressor including an axial compressor and / or a centrifugal compressor for treating a gas flow. BACKGROUND OF THE INVENTION The subject matter of this disclosure is specifically directed to a method and system for controlling a compressor device to prevent a phenomenon deviating from a operating envelope, such as surge and other undesirable operating conditions.

Turbo compressors are one-piece turbomachinery used to boost pressure in a gas-phase working flow. The pressure of the working fluid is increased by adding kinetic energy to the continuous flow of the working fluid through rotation of the rotor supporting one or more impellers and / or one or more sets of blades in a circular array. Turbo compressors are often used to transport natural gas pipelines, for example, to move gas from a production site to consumer locations in gas and oil applications, refrigeration systems, gas turbines, and other applications.

The flow of fluid through the turbocompressor can be affected by various conditions that result in unstable operation that can cause serious damage to the turbomachine.

The compressor surge occurs when the pressure of the working fluid flowing through the compressor increases beyond an acceptable maximum output pressure and / or when the flow rate falls below a minimum limit.

Generally, a compressor occurs when it can not add enough energy to the working fluid to overcome the system resistance, i.e., head drop across the system, resulting in rapid flow and reduced discharge pressure. The surge can be accompanied by high vibrations, temperature increases and rapid changes in the axial thrust on the bearings of the compressor shaft. This phenomenon can also severely damage the compressor and components of the system connected to the compressor, such as valves and piping.

Other undesirable operating conditions may occur during operation of the turbocompressor. More specifically, chokes (sometimes referred to as stonewalls) are conditions in which increased flow results in a rapid decrease in the head and compression ratio of the flow increases. Operation at high flow rates adversely affects compressor performance and may cause compressor damage.

To prevent surge and choke phenomena, control systems have been developed and are now being used in turbo compressor installations.

1 schematically shows an exemplary embodiment of a system 1 consisting of a prime mover 5, for example a turbo compressor 3 driven to rotate by an electric motor, gas or steam turbine or the like. Reference numeral 7 denotes a suction line from which the working fluid is supplied to the suction side or the inflow side of the turbo compressor 3. [ Reference numeral 9 designates a conveying pipe through which the compressed fluid is conveyed from the discharge side of the compressor 3.

Figure 2 schematically illustrates a compressor performance map, typically a compressor performance map of an axial compressor. The compressor performance map shows the pressure ratio along the vertical axis and the inlet volumetric flow recorded on the horizontal axis. The influent flow is represented by the letter Q. Depending on the operating conditions of the compressor, for example the rotational speed (rpm), a plurality of expected performance curves can be recorded in the compressor performance map. Each curve may correspond to a different compressor rotational speed. Thus, for a given compressor set-up, a group of performance curves can be recorded in the compressor performance map. Similar curves can be obtained for different setups or operating conditions of the turbocompressor, e.g., for various positions of a Variable Stator Vane (VSV). Each performance curve will be limited by the bimodal point, ie, the pressure ratio through the compressor and the point at which the gas flow attains the desired value, and the surge will occur when it crosses the surge point. In each case, the performance curve is further limited by the choke point, and a choke phenomenon occurs when the choke point is exceeded. The line SLL is a so-called Surge Limit Line formed by the surge points of the various performance curves recorded on the compressor performance map. The line CLL is the choke limit line formed by the choke point. The lines SLL and CLL form part of the performance map, which must be maintained at the operating point of the compressor in order to guarantee a limit, i.e., a stable operating condition of the turbo compressor and to prevent surge and choking conditions.

Accordingly, SLL and CLL represent the operating limits of the turbo compressor, and beyond this operating limit, the turbocompressor will not work to prevent the risk of surges and choke phenomena. The known compressor system consists of a control device and a device for controlling the turbo compressor so that the turbo compressor continuously operates within the stabilization zone of the performance map, i.e. between the surge limit line SLL and the choke limit line CLL.

In the diagram of Figure 1, the control unit 11 is connected to various devices surrounding the turbo compressor to determine the operating conditions of the turbomachine and to provide surge and choke control to prevent surge and choke phenomena from occurring to provide.

1, the control unit 11 is connected to a flow rate measuring device, also referred to as a flow rate element 13, which is designed and configured to determine the inlet volumetric flow rate of the turbocompressor 3. The temperature sensor on the inlet side or the suction side provides the temperature value Ts and the pressure sensor provides the delivery pressure value Pd and the suction pressure value Ps or directly the compressor Pd / Ps.

Based on the input data, the control unit 11 can determine the inlet volumetric flow rate and the pressure ratio at each and every moment of the operation of the turbo compressor 3. These two parameters form the operating point on the compressor performance map of FIG. As another parameter, the rotational speed N (rpm) of the compressor can be provided, so that the correct operating curve can be selected to determine the actual position of the compressor operating point in the performance map. When the operating point moves close to the surge limit line SLL, the surge control system activates the surge protection bypass valve. The surge prevention bypass valve 15 is disposed on the bypass line 17 connecting the delivery side and the suction side of the compressor 3. The working fluid portion delivered by the turbo compressor 3 can be recycled through the surge protection valve 15 to prevent surge if necessary. When the transfer pressure increases so that the operating point approaches the surge limit line SLL, the surge suppression control device opens the surge protection bypass valve 15 so that the flow rate through the compressor can be increased and the transfer pressure can be reduced.

The working fluid can be cooled in the heat exchanger 19 before it is recirculated through the surge protection valve 15.

In some embodiments, the surge control device may provide a bleeding line, along which a surge protection valve is disposed which, if the nature of the gas permits, allows the process gas to be discharged to the ambient environment .

The choking of the compressor can be prevented by closing the choke control valve disposed along the suction line 7 or along the discharge line upstream or downstream of the turbo compressor 3. [

The actual known solution requires a flow element 13 to determine the operating point of the compressor for the purpose of preventing surging. In some applications, the flow element 13 may be difficult to handle and may require a relatively long pipe upstream or downstream to accurately measure the incoming flow rate. It may be difficult to provide a measuring element or device on the inlet or suction side of a turbo compressor, in particular an air turbo compressor.

SUMMARY OF THE INVENTION The subject matter disclosed herein relates to an improved method and apparatus for providing surge protection control of a compression system comprising at least one compressor. In some embodiments, the method and apparatus provide surge protection and / or choke prevention of the compressor.

In some embodiments, at least one operating limit is established and the compressor is controlled such that its operating point lies within the operating limit. An action is taken when the operating point belongs to or outside the operating limit boundary, or when the operating point is close to the boundary of the limiting point. Operating limits include two operating parameters of the compressor; Based on a performance map based on the correction speed and the pressure ratio of the compressor. The pressure ratio is the ratio between the delivery pressure of the compressor and the suction pressure. The correction speed is defined according to the suction temperature processed by the compressor and the rotation speed of the compressor. The correction rate is thus calculated according to the following equation,

Lt; RTI ID = 0.0 >

Ts is the processing fluid temperature at the inlet of the compressor,

N is the rotational speed of the compressor.

The correction rate is defined by the ratio when the gas component is constant. Thus, the method disclosed herein is suitable for the surge / choke prevention of compressors that process gases having known constant components, such as carbon dioxide.

The operating limits can be delimited by the suction limit line, the choke limit line as well as the allowable maximum correction speed and the allowable minimum correction speed.

When the compressor is provided with a movable inlet guide vane, that is, a variable stator vane, the operating limit point can be defined for each position of the variable stator vane. Accordingly, some of the plurality of operating limit points are formed in the correction speed versus compression ratio diagram or performance map. Depending on the actual position of the variable stator vane, corresponding operating limits for surge and / or choke prevention control are selected. Because the position of the variable stator vanes typically varies in a continuous manner, according to some embodiments, a limited number of operating limits corresponding to the different positions of the variable stator vanes are determined. If the actual position of the variable stator vane is changed by interpolating, for example, two nearest operating limit points-the data is available for it-when the limit point is determined and the associated data is different from the location stored for control purposes An intermediate operating limit point is calculated.

According to some embodiments there is thus provided a method of controlling a turbo compressor to prevent surge,

Providing at least one surge limit line and / or at least one choke line for at least one operating condition of the turbocompressor;

Continuously measuring the operating point of the compressor by measuring the process gas temperature at the compressor inlet, the rotational speed of the compressor, and the transfer and suction pressure values;

에 비례하는 터보압축기의 보정 속도의 실제값을 연속적으로 결정하는 단계,ratio

Continuously determining an actual value of the correction speed of the turbo compressor proportional to the actual speed of the turbo compressor,

Continuously determining at least an allowable maximum pressure ratio on the surge limit line and / or at least an allowable minimum pressure ratio on the choke limit line, corresponding to the actual value of the correction rate,

Continuously determining an actual pressure ratio equal to the ratio of the transfer pressure to the suction pressure; And

Operating the surge protection device to recycle a portion of the compressed gas in the compressor through the suction line when the actual pressure ratio is above the allowable maximum pressure ratio or below the allowable minimum pressure ratio

.

In the context of this disclosure and the appended claims, the term "continuously determining" a parameter also includes determining the parameter at constant time intervals or at variable time intervals during continuous operation of the compressor.

In a preferred embodiment, the surge limit line forms the operating point of the operating limit point compressor with the choke limit line and the allowable maximum and minimum correction lines being maintained within this operating limit point.

If the operating point of the compressor is close to the surge limit line, the surge suppression device may be affected. The surge suppression device may be any device known from the art. The surge is prevented by opening the surge protection bypass valve. In certain embodiments, when the process gas is air, the surge can be prevented by venting or delivering a portion of the compressor moving flow to the ambient environment. In both cases, the transfer flow is increased, thereby displacing the operating point of the compressor away from the surge limit line.

The method may further comprise a preceding step of detecting the type of gas or gas component entering the turbo compressor.

Since the correction rate is related to the gas component or type, gas detection and prediction can allow on-line continuation setting of the method.

In particular, when the working gas has a component that is not constant over time, the method requires information about the gas being processed by the turbocompressor. To obtain this information, any gas detector known in the art, such as process gas chromatography may be used.

The apparatus may also include an appropriate database containing operating limits associated with each gas.

When the operating point of the compressor approaches the upper limit of the correction speed or the lower limit of the correction speed, it is possible to take action to reduce or increase the rotation speed of the compressor, respectively.

When the operating point of the compressor approaches the choke limit line, the choke prevention device can be actuated. The device may be any device known in the art. For example, the choke prevention valve may be closed.

In some embodiments, a variable stator vane, i.e., a movable inlet guide vane, may be provided on the suction side of the compressor. The variable stator vane can be used as a control means to prevent the operating point of the compressor from approaching or moving past the line forming the boundary of the operating limit. The choke can be prevented, for example, by reducing the inflow cross-sectional area and hence the inflow flow of compressed gas.

The variable stator vane can be operated to prevent the operating point of the compressor from moving above the correction speed upper limit or falling below the correction speed lower limit.

According to another aspect, the subject matter disclosed herein is directed to an apparatus for providing surge protection and / or choke prevention control for a compression system comprising at least one compressor, the apparatus performing the control method described above. According to a further aspect, the object to be protected as disclosed herein relates to a compression system consisting of at least one compressor and to the device for surge and / or choke prevention control.

According to another aspect, the subject of protection disclosed herein is a method of conditioning a turbocompressor,

Determining at least one compressor operating limit point for the corrected speed versus compressor diagram or performance map by the choke limit line, the surge limit line, the allowable maximum speed line, and the allowable minimum speed line;

Continuously determining an operating point of the turbo compressor for the correction rate versus compression ratio diagram;

Determining whether an operating point is within an operating limit; And

Operating the activation system to modify at least one operating parameter of the turbo compressor if the operating point of the turbo compressor does not fall within the operating limit < RTI ID = 0.0 >

And a control method of the turbo compressor.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, features and embodiments are disclosed, and these features and embodiments are further described in the appended claims, which form an integral part of the description. The foregoing brief description describes features of various embodiments of the present invention in order to provide a better understanding of the following detailed description and to better appreciate the contribution of the present invention to the art. It is to be understood that there are other features of the invention which will be described hereinafter and described in the appended claims. Before describing in detail several embodiments of the invention in this aspect, it is to be understood that the various embodiments of the invention are not limited to the details of construction in the application and to the arrangement of the components described in the following description or illustrated in the drawings I understand. The invention is capable of other embodiments and of being practiced and of being practiced in various ways. Moreover, the jargon and terminology used herein is for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the concepts based on this disclosure may be readily utilized as a basis for constructing other structures, methods, and / or systems to accomplish the various objects of the present invention. It is important, therefore, that the claims be considered to include such equivalent constructions unless they depart from the spirit and scope of the invention.

The foregoing embodiments and advantages will be more fully understood when the disclosed embodiments of the present invention and the various attendant advantages of the present invention are better understood by referring to the detailed drawings considered together with the accompanying drawings.
1 is a schematic diagram of a compressor system according to the prior art,
2 is a diagram illustrating a compressor performance map currently used in a surge prevention and choke prevention control system,
3 is a schematic diagram of a compressor system according to the present disclosure,
Figure 4 is a schematic view similar to that of Figure 3 in a system comprising a turbo compressor with movable variable stator vanes,
5 is a diagram illustrating a compressor performance map according to the present disclosure showing one operating limit point,
6 is a diagram illustrating a compressor performance map showing two overlapping operating points corresponding to two different positions of a movable inflow guide vane or variable stator vane of a turbocompressor,
7 is a flow chart summarizing the control algorithm according to the present disclosure;

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

Reference throughout this specification to "one embodiment" or "an embodiment" or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment . Accordingly, the appearances of the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout this specification are not necessarily referring to the same embodiment (s). Furthermore, a particular feature, structure, or characteristic may be combined in any suitable manner in one or more embodiments.

Figure 3 schematically illustrates a compressor system 20 implementing the protected object described herein. The compressor system 20 includes a turbo compressor 21, such as a centrifugal or axial turbo compressor. The turbo compressor 21 is driven to rotate by the actuator 23. In some embodiments, the mover 23 may be an electric motor. In another embodiment, the mover 23 may be a gas turbine, such as an aero derivative gas turbine. In another embodiment, different prime movers, such as steam turbines, may be used. The load coupling 25 connects the prime mover 23 with the turbo compressor 21. A speed manipulation device (not shown), such as a gearbox, may be disposed between the prime mover and the turbo compressor 21.

The working gas is supplied through the suction line 25 to the inlet side or the suction side of the turbo compressor 21 and the compressed fluid is transferred from the transfer side of the compressor through the transfer line or pressure line 27. A safety or check valve 29A, 29B may be arranged in the suction line and / or the pressure line 27.

A heat exchanger 31 may be arranged along the bypass line 33 connecting the pressure line 27 to the suction line 25 as shown on the compression line 27 or as dashed at 31x . A surge prevention bypass valve 35 is disposed along the bypass line 33. The anti-surge valve 35 is controlled by a surge protection 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 vented to the air or to the external environment, the surge protection valve 35 is configured to allow the working fluid to be discharged directly into the atmosphere, even if some are recirculated through the suction line 25 May be disposed on the delivery line.

To detect the working gas entering the turbo compressor, the system may be equipped with an apparatus 50 for detecting the component or type of gas. Such a device may be a particular type of gas chromatograph.

A control unit 39 is also provided in the system 20. The control unit 39 also interfaces with the pressure sensor as well as the temperature sensor 41 on the inlet or suction side of the turbo compressor 21. [ The pressure sensor provides a direct or indirect measure of pressure ratio between the transfer side and the suction side of the compressor. For example, in the schematic diagram of Fig. 3, the feed-side pressure sensor 43 provides the feed 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 measure of the suction process Ps at the inlet of the turbo compressor 21. Based on these two measured pressure values Pd, Ps, the pressure ratio can be calculated by the control unit 39. In another embodiment, the pressure ratio can be determined outside the control unit 39, and the pressure ratio value can be directly input to the control unit 39. [

The rotational speed sensor further provides the control unit 39 with a rotational speed value N (expressed in rpm).

On the basis of the above-mentioned operating parameters, the control unit 39 can thus calculate not only the pressure ratio of the compressor, but also the so-called correction speed of the compressor as defined below:

Where C1 is a function of temperature, pressure and gas composition,

N is the rotational speed of the turbo compressor 21,

And Ts is the absolute temperature at the suction portion of the turbo compressor 21. [

The argument C1 is a function of the gas component and is considered constant if the gas has an invariant component and T and P are within a limited range.

If the gas has a constant component of the base, the correction rate can be simplified as:

The correction rate can be used to form a compressor performance map, in which case the correction rate is written to one of the coordinate axes and the pressure ratio is recorded in the remaining coordinate axes.

Figure 5 schematically shows a performance map of the type described above in which the correction rate is recorded on the vertical axis and the pressure ratio Pd / Ps is recorded on the horizontal axis. On this performance map, surge limit line SLL can be shown. In order to prevent the surging phenomenon, the turbo compressor 21 can be operated such that its operating point on the performance map of Fig. 5 is maintained on the surge control line or on its left hand side, Or it will not work past the SLL.

On the same performance map of FIG. 5, a choke limit line CLL may also be shown, and CLL represents a limit beyond which the choking phenomenon may occur. In order to operate the compressor 21 without choking, the operating point of the compressor will not move past the CLL in the left hand side of the choke limit line.

The performance map of Figure 5 shows two different lines, the allowable minimum correction speed line Nc mim and the maximum allowable correction speed line Nc max. The latter being a straight line parallel to the horizontal coordinate axis (abscissa), below which an allowable minimum correction rate at which the compressor does not operate; And the maximum correction rate over which the turbo compressor operates.

The four lines defined above form the operating limit OE. The compressor control system will control the compressor such that the operating point of the compressor is maintained within the operating limit OE. In Fig. 5, an exemplary operating point labeled OP, corresponding to a correction speed value Nc and a pressure ratio PR = Pd / Ps, is shown.

The control system is designed and constructed such that the operating condition of the turbo compressor 21 when the operating point OP moves to the right to reach the surge limit line SLL is modified to bring the operating point OP back into the operating limit OE. This can be done, for example, by opening the surge protection valve 35. When the operating point OP moves to the left until it reaches the choke limit line CLL, the control system will operate to modify the flow conditions to bring the operating point back into the operating limit OE. This can be implemented, for example, by operating the choke prevention valve 47.

Moving below the allowable minimum correction speed value (Nc) min when the operating point OP is moved down (Nc) to the min line is prevented by increasing the rotational speed of the turbo compressor (21). Moving the operating point to exceed the allowable maximum speed value (Nc) Max is thereby prevented by reducing the rotational speed of the turbo compressor (21).

In the simplified schematic of Figure 3, the turbo compressor 21 is not provided with a movable inlet guide vane or variable stator vane (VSV). The latter is typically provided in a common compressor to modify the shape of the inlet section according to the operating conditions of the system. Figure 4 shows the same system of Figure 3 with a variable stator vane schematically shown at 51 added. The same reference numerals as in Fig. 3 denote the same or corresponding components or parts, and will not be described again. In the system of Fig. 4, the control unit 35 further receives information on the actual position of the variable stator vane of the turbo compressor 21. Reference numeral VSV denotes information on the actual position of the variable stator vane during operation of the turbo compressor 21. [ The VSV position can be set by an appropriate actuator not shown. The actuators can be controlled by the same control unit 37.

In the schematic diagram of Fig. 4, the choke prevention valve 47 is omitted, because choking can be prevented by actuating the VSV as an alternative. The latter is closed to reduce the inlet volumetric flow rate of the turbo compressor to prevent choking of the compressor without the need to use a choke valve.

In fact, different performance maps and thus different operating limits can be obtained for each possible position of the movable variable stator vane 51. [ This is schematically shown in FIG. 6, where two different operating limits labeled OE1 and OE2 are shown in FIG. Each operating limit is delimited by four curves defined in two cases in the same manner as described above in conjunction with FIG. Thus, each operating limit is delimited by the surge limit line SLL, the choke limit line CLL, the allowable maximum correction speed line Nc max and the allowable minimum correction speed line Nc min.

In fact, an infinite number of operating limits for each position of each variable stator vane can be provided. The data defining each operating limit point is accessible by the control unit and may be stored in the memory schematically shown at 38 in Figs. 3 and 4. In a practical embodiment, only a finite number of operating limits will be calculated and stored in the form of, for example, a lookup table. During operation of the turbo compressor 21, the control unit 37 will use an operating limit point corresponding to the actual position of the variable stator vane if such an operating limit exists. If the actual position of the variable stator vane differs from the position of the variable stator vane stored in the control system, the control unit may be able to determine, for example, two nearest positions-an operating limit for these positions available in the storage memory- Using the corresponding data, we will calculate the operating limit by interpolation of the existing data.

The operation of the system described so far will become more apparent from the following description with reference to the flow chart of Fig. 7 as well as the above figures. In the latter, the control process appears as a series of steps. It should be understood that in order to obtain continuous control of the operating conditions of the compressor 21, the sequence of the method steps shown in FIG. 7 during the operation of the system will be repeated continuously or repeatedly.

At the start of the control process, the correction speed Nc is determined. This is done by detecting the rotation speed N and the temperature Ts on the suction side of the turbo compressor 21. [ When the variable stator vane 51 as described in connection with FIG. 4 is provided in the turbo compressor 21, the VSV position is determined. Based on the data relating to the actual position of the variable stator vane, the operating limit point is calculated, for example, using the data stored in the storage memory 38. As discussed above, operating limit point data may be stored directly in storage memory 38 for some variable stator vane locations. In other intermediate positions, the operating limit point may be calculated, for example, by interpolating existing data.

Once the operating limit point has been determined, the maximum and minimum pressure ratios for the actual correction rate Nc can be determined. These maximum and minimum pressure ratios are denoted by PRmax and PRmin in Fig.

The actual operating point of the compressor is then determined on the basis of the actual pressure ratio determined by the correction speed Nc calculated as described above and the suction pressure Ps measured by the pressure sensor-the transfer pressure Pd of the turbo compressor 21 . The actual pressure ratio is represented by PR in Fig.

At this time, the control system has all the data required to operate the surge protection and / or choke prevention device to prevent choking or surging of the system. In some embodiments, the surge parameter and the choke parameter are calculated as follows. The surge parameters are defined as follows:

In this formula,

PRmax is the allowable maximum pressure ratio;

PR is the actual pressure ratio.

The choke parameter can be defined as:

In this formula,

PRmin is the allowable minimum pressure ratio.

The surge parameter and the choke parameter can be used to generate a control signal to actuate the actuator, which controls the surge protection valve 35 and choke prevention valve 47 and / or the VSV 51. When the surge parameter becomes 1, that is, when the operating point moves onto the surge control line, the actuator of the surge protection valve 35 is operated to at least partially open the surge protection valve 35 on the bypass line 33 will be. In order to move the operating point OP back to the operating limit OE, the working gas is recirculated from the delivery side to the suction side of the turbo compressor. When the choke parameter is equal to 1, the choke valve 47 on the suction line 25 will be partially closed to reduce the suction flow and to move the operating point of the turbo compressor back into the operating limit OE.

The actual correction speed value Nc is known by the control system and may be adjusted by the turbo compressor 21 if necessary to prevent the correction speed from falling below the allowable minimum value Nc min or from exceeding the allowable maximum value Nc max ) Can also be performed. In some embodiments, if the correction rate value Nc falls below the allowable minimum value or exceeds the allowable maximum value, the position of the VSV may be modified to move the turbo compressor to a different operating point of a different operating limit point.

Although the disclosed embodiments of the subject matter disclosed herein have been shown and described in detail and in sufficient detail in connection with a number of several embodiments, it will be appreciated that the novel teachings, principles and concepts described herein, It will be apparent to those skilled in the art that various modifications, variations, and omissions without departing from the scope of the appended claims are possible. Accordingly, the appropriate scope of the innovation disclosed should be determined only by broadly construing the appended claims to cover all such modifications, variations and omissions. Also, the order or order of any process or method steps may be changed or redefined according to a variant.

Claims (15)

A method for controlling a turbo compressor to prevent surge,
Providing at least one surge limit line (SLL) and / or at least one choke limit line (CLL) of the turbocompressor;
Continuously determining the operating point of the turbo compressor by measuring the process gas temperature Ts at the compressor inlet, the rotational speed N of the turbo compressor, the feed pressure value Pd, and the suction pressure value Ps;
ratio

Continuously determining an actual value of a correction speed Nc of the turbo compressor proportional to the actual speed Nc of the turbo compressor;
At least an allowable maximum pressure ratio PRmax on the surge limit line SLL and / or at least an allowable minimum pressure ratio PRmin on the choke limit line CLL, corresponding to the actual value of the correction speed Nc, Determining;
Continuously determining an actual pressure ratio (PR) equal to the ratio of the transfer pressure to the suction pressure (Pd / Ps); And
Operating the surge protection device to recycle a portion of the compressed gas of the turbocompressor through the suction line when the actual pressure ratio PR is greater than or equal to the allowable maximum pressure ratio PRmax or less than the allowable minimum pressure ratio PRmin
/ RTI > The method according to claim 1,

Calculating a surge parameter defined as a surge parameter; And
Using the surge parameter to control the surge protection device
Further comprising:
PRmax is the allowable maximum pressure ratio,
Wherein PR is an actual pressure ratio. 3. The method according to claim 1 or 2,

Calculating a choke parameter defined as a choke parameter; And
Using the choke parameter to control the choke prevention device
Further comprising:
PRmin is the allowable minimum pressure ratio.
Wherein PR is an actual pressure ratio. 4. The method according to any one of claims 1 to 3,
Providing at least one permissible maximum correction rate (Nc) max and at least one permissible minimum correction rate (Nc) min of the turbo compressor;
If the actual value of the correction speed Nc is greater than the allowable maximum correction speed Nc max, reducing the rotational speed N of the turbo compressor; And
If the actual value of the correction speed Nc is smaller than the allowable minimum correction speed Nc min, the step of increasing the rotation speed N of the turbo compressor
Further comprising the steps of: 5. The method according to any one of claims 1 to 4,
Providing a variable stator vane (51) at an inlet of the turbo compressor (21);
Determining a parameter indicative of a position of a variable stator vane (VSV); And
(SLL) and a choke limit line (CLL) according to the parameter among a plurality of surge limit lines (SLL) and / or a plurality of choke limit lines (CLL) corresponding to respective positions of the variable stator vanes Step to Select
Further comprising the steps of: 6. The method according to any one of claims 1 to 5,
Setting an allowable maximum correcting speed (Nc) max and an allowable minimum correcting speed (Nc) min corresponding to the position of the variable stator vane (VSV); And
When the actual value of the correction speed Nc is larger than the allowable maximum correction speed Nc max or the actual value of the correction speed Nc is smaller than the allowable minimum correction speed Nc min, Steps to activate
Further comprising the steps of: The method of any one of claims 1 to 6, further comprising a preceding step of detecting the type of gas entering the turbocompressor. A surge suppression control device for providing a surge protection control for a compression system comprising at least one compressor, the surge protection control device being arranged and configured to perform the method according to any one of claims 1 to 7. . An anti-surge control device (37) for providing a surge protection control for a compression system comprising at least one compressor (21)
A data storage device (38) comprising data forming at least one surge limit line (SLL) and / or at least one choke limit line (CLL) of the compressor;
An apparatus for continuously determining an operating point of a compressor, comprising: A temperature sensor 41 for measuring the process gas temperature Ts at the compressor inlet, a rotational speed sensor for measuring the rotational speed N of the compressor, and a pressure sensor for measuring the feed pressure value Pd and the suction pressure value Ps (43, 45);
ratio

An apparatus for continuously determining an actual value of a correction speed Nc of a turbo compressor,
At least an allowable maximum pressure ratio PRmax on the surge limit line SLL and / or at least an allowable minimum pressure ratio PRmin on the choke limit line CLL, corresponding to the actual value of the correction speed Nc, A device for determining;
An apparatus for continuously determining an actual pressure ratio PR equal to the ratio of the feed pressure to the suction pressure (Pd / Ps); And
A surge protection device 35 operated to recycle a portion of the compressed gas in the compressor 21 through the suction line 25 when the actual pressure ratio PR is equal to or greater than the allowable maximum pressure ratio or below the allowable minimum pressure ratio,
And a surge suppression control unit. 10. The method of claim 9,

Further comprising a device for calculating a surge parameter defined as < RTI ID = 0.0 >
PRmax is the allowable maximum pressure ratio,
And PR is an actual pressure ratio. 11. The method according to claim 9 or 10,

Further comprising a device for calculating a choke parameter defined as < RTI ID = 0.0 >
PRmin is an allowable minimum pressure ratio,
And PR is an actual pressure ratio. 12. A method as claimed in any one of the claims 9 to 11, characterized in that the storage device (38) comprises at least one permissible maximum correction rate (Nc) max of the compressor (21) ) < / RTI > min,
If the actual value of the correction speed Nc is larger than the allowable maximum correction speed Nc max, the rotation speed N of the compressor 21 is decreased and the actual value of the correction speed Nc becomes the allowable minimum correction speed Nc. min, a speed control device is provided to control the rotation speed (N) of the compressor so as to increase the rotation speed (N) of the compressor (21). 13. The method according to any one of claims 9 to 12,
Further comprising an activation device for controlling the position of the variable stator vane (51) of the compressor (21)
The storage device (38) comprises data forming a plurality of surge limit lines (SLL) and / or choke limit lines (CLL), corresponding to a plurality of respective positions of the variable stator vanes (51) Prevention control device. A compression system comprising at least one compressor (21) and an apparatus according to one or more of claims 9 to 13 for anti-surge control of the compressor. 15. The system of claim 14, further comprising an apparatus (50) for detecting the type of gas entering the turbo compressor.

Images