JP2016211469A - Compressor juxtaposition operation load decentralization system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor juxtaposition operation load decentralization system and method capable of optimizing the operation efficiency even respect with different performance compressors while load distribution control can be performed regardless of the system configuration.SOLUTION: A compressor juxtaposition operation load decentralization system comprises: compressors 12 and 22a/22b respectively connected to pipelines 11a/11b and 21a to 21c connected in parallel; and a control device that performs the parallel operation of the compressors 12 and 22a/22b as well as the load distribution. The control device includes: computing units 42 and 52a to 52c that obtain correlation values correlating to the substantial efficiencies of the compressors 12 and 22a/22b for each of the pipelines 11a/11b and 21a to 21c; a computing unit 32 that selects any one of a largest value, an average value, or a minimal value of a plurality of the obtained correlation values as a selected value; and LSCs 43 an 53 for controlling all the compressors 12 and 22a/22b on the basis of the selected value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a compressor parallel operation load distribution system and method when a plurality of compressors are connected in parallel.

  There is a compressed gas supply system in which a plurality of compressors are connected in parallel and these compressors are operated in parallel. In such a supply system, the plurality of compressors are controlled so that the load is distributed.

  In the supply system as described above, there are methods as described in Patent Documents 1 and 2 as load setting methods. For example, in Patent Document 1, by dividing the fuel flow rate of each compressor equally, the load is distributed so that the power consumption of each compressor becomes equal. In Patent Document 2, the load is distributed by averaging the relative distance from the surge control line to the operating point in each compressor. The surge control line is a line obtained by subtracting the safety limit from the surge limit line.

Japanese Patent Laid-Open No. 3-213697 JP-A-6-88597

  However, Patent Document 1 has a configuration in which two series of compressors are connected in parallel. When three or more series of compressors are connected in parallel, the above-described method cannot be applied, and the rated consumption of each compressor Even when the power is different, the above-described method cannot be applied. Also in Patent Document 2, when the performance of each compressor is different, even if the relative distances described above are averaged, high operating efficiency cannot always be realized.

  The present invention has been made in view of the above problems, and it is possible to perform load distribution control regardless of the system configuration, and to parallelize compressors that can optimize operation efficiency even when there are compressors having different performances. An object is to provide an operating load distribution system and method.

A parallel operation load distribution system for compressors according to a first invention for solving the above-described problems is as follows.
One or more compressors each connected to a plurality of pipes connected in parallel;
A controller for operating the plurality of compressors in parallel and distributing the load,
The controller is
For each pipe, a calculation unit for obtaining a correlation value that correlates with the real efficiency or the real efficiency of the compressor of the pipe;
A selection unit that selects, as a selection value, any one of a plurality of the obtained real efficiencies or a maximum value, an average value, or a minimum value of the correlation values;
And a control unit that controls all of the compressors based on the selection value.

A parallel operation load distribution system for compressors according to a second invention for solving the above-described problems is as follows.
In the parallel operation load distribution system of the compressor according to the first invention,
For each of the compressors, the calculation unit obtains an efficiency curve in advance by linearly interpolating a plurality of operating points with the highest operating efficiency from the performance curve of the compressor, and calculates the efficiency from the current operating point of the compressor. While calculating the relative distance to the curve, the efficiency distance obtained by converting the relative distance into an absolute value, and using the efficiency distance as the correlation value,
The control unit converts the selected value into the original relative distance and controls all the compressors so as to converge to the converted original relative distance.

A compressor parallel operation load distribution system according to a third aspect of the present invention for solving the above problems
In the parallel operation load distribution system of the compressor according to the second invention,
When a plurality of the compressors are connected in series to the pipe,
The arithmetic unit selects a plurality of maximum values of the efficiency distances for the plurality of compressors connected in series, and uses the selected maximum values as the correlation values.

A compressor parallel operation load distribution system according to a fourth aspect of the present invention for solving the above problems
In the parallel operation load distribution system of the compressor according to the second invention,
When a plurality of the compressors are connected in series to the pipe,
The calculation unit obtains a performance curve obtained by integrating performance curves of the plurality of compressors connected in series with respect to the plurality of compressors connected in series, and determines a plurality of operating points with the highest operating efficiency from the performance curve. An efficiency curve is obtained in advance by linear interpolation, and a relative distance from the current operating point of one of the compressors connected in series to the efficiency curve is calculated, and the relative distance An efficiency distance obtained by converting the absolute value into an absolute value is obtained, and the efficiency distance is used as the correlation value.

A compressor parallel operation load distribution system according to a fifth aspect of the present invention for solving the above problems
In the parallel operation load distribution system of the compressor according to the first invention,
The calculation unit obtains the substantial efficiency from the current operating point of the compressor of the pipe for each pipe,
The control unit controls all the compressors so as to converge to the substantial efficiency that is the selected value selected.

A compressor parallel operation load distribution system according to a sixth aspect of the present invention for solving the above problems
In the parallel operation load distribution system of the compressor according to the fifth aspect of the invention,
And a switching unit that switches between positive and negative signs of the selected value,
The switching unit obtains in advance the flow rate at the maximum efficiency point at which the efficiency is maximum from the compressor efficiency-flow rate curve for the pipe, and the flow rate at the current operating point of the compressor is the maximum flow rate. When the flow rate is higher than the efficiency point, the sign of the selection value is switched to negative, and when the flow rate is less than or equal to the maximum efficiency point, the sign of the selection value is switched to positive.

A compressor parallel operation load distribution method according to a seventh aspect of the present invention for solving the above-described problems is as follows.
For a compressor connected to one or more pipes connected in parallel with each other, in a parallel operation load distribution method for a compressor that performs load distribution while simultaneously operating the plurality of compressors,
For each pipe, a calculation step for obtaining a correlation value that correlates with the real efficiency or the real efficiency of the compressor of the pipe; and
A selection step of selecting, as a selection value, any one of a plurality of obtained real efficiencies or a maximum value, an average value, or a minimum value of the correlation values;
And a control step of controlling all the compressors based on the selected value.

A compressor parallel operation load distribution method according to an eighth aspect of the present invention for solving the above-described problems is as follows.
In the compressor parallel operation load distribution method according to the seventh aspect of the invention,
In the calculation step, for each of the compressors, an efficiency curve is obtained in advance by linearly interpolating a plurality of operating points with the highest operating efficiency from the performance curve of the compressor, and the efficiency is calculated from the current operating point of the compressor. While calculating the relative distance to the curve, the efficiency distance obtained by converting the relative distance into an absolute value, and using the efficiency distance as the correlation value,
The control step converts the selected value into the original relative distance and controls all the compressors so as to converge to the converted original relative distance.

A compressor parallel operation load distribution method according to a ninth aspect of the invention for solving the above-described problems is as follows.
In the compressor parallel operation load distribution method according to the eighth aspect of the invention,
When a plurality of the compressors are connected in series to the pipe,
The calculating step selects a plurality of maximum values of the efficiency distances for the plurality of compressors connected in series, and uses the selected maximum value as the correlation value.

A compressor parallel operation load distribution method according to a tenth aspect of the present invention that solves the above-described problem,
In the compressor parallel operation load distribution method according to the eighth aspect of the invention,
When a plurality of the compressors are connected in series to the pipe,
The calculation step obtains a performance curve obtained by integrating performance curves of the plurality of compressors connected in series with respect to the plurality of compressors connected in series, and determines a plurality of operating points with the highest operating efficiency from the performance curve. An efficiency curve is obtained in advance by linear interpolation, and a relative distance from the current operating point of one of the compressors connected in series to the efficiency curve is calculated, and the relative distance An efficiency distance obtained by converting the absolute value into an absolute value is obtained, and the efficiency distance is used as the correlation value.

A compressor parallel operation load distribution method according to an eleventh aspect of the present invention for solving the above-described problems is as follows.
In the compressor parallel operation load distribution method according to the seventh aspect of the invention,
The calculation step calculates the substantial efficiency from the current operating point of the compressor of the pipe for each pipe,
In the control step, all the compressors are controlled so as to converge to the substantial efficiency that is the selected value selected.

A compressor parallel operation load distribution method according to a twelfth aspect of the present invention for solving the above-mentioned problems is as follows.
In the compressor parallel operation load distribution method according to the eleventh aspect,
And a switching step of switching between positive and negative signs of the selected value,
In the switching step, the flow rate at the maximum efficiency point at which the efficiency is maximized is determined in advance from the efficiency-flow rate curve of the compressor for the piping, and the flow rate at the current operating point of the compressor is the maximum flow rate. When the flow rate is higher than the efficiency point, the sign of the selection value is switched to negative, and when the flow rate is less than or equal to the maximum efficiency point, the sign of the selection value is switched to positive.

  According to the present invention, load distribution control of a plurality of compressors can be performed regardless of the system configuration such as the number of compression stages and the number of trains, and operation efficiency is optimized even when there are compressors having different performances. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows an example (Example 1) of embodiment of the parallel operation load distribution system of the compressor which concerns on this invention. It is a performance curve figure explaining the parallel operation load distribution method in the parallel operation load distribution system of the compressor shown in FIG. It is a schematic block diagram which shows the modification of the system shown in FIG. 1 as another example (Example 2) of embodiment of the parallel operation load distribution system of the compressor which concerns on this invention. It is a schematic block diagram which shows another example (Example 3) of embodiment of the parallel operation load distribution system of the compressor which concerns on this invention. FIG. 6 is a diagram showing a modification of the system shown in FIG. 3 as another example (Example 4) of the embodiment of the parallel operation load distribution system for compressors according to the present invention, and FIG. It is a figure and (b) is the schematic block diagram.

  Hereinafter, embodiments of a parallel operation load distribution system and method for a compressor according to the present invention will be described with reference to FIGS.

[Example 1]
As shown in FIG. 1, the compressor parallel operation load distribution system in the present embodiment includes a plurality of trains T1 and T2 that connect the inlet header H1 and the outlet header H2 in parallel. The inlet header H1 is provided with a pressure measuring device 10 for control described later.

  The train T1 includes a pipe 11a connected to the inlet header H1, a pipe 11b connected to the outlet header H2, and one compressor 12 connected between the pipe 11a and the pipe 11b. The compressor 12 is driven by a driving machine 13 including a motor or a steam turbine.

  In this train T1, a check valve 14 is provided in the pipe 11b, and a recirculation pipe 15 is connected from the pipe 11b upstream of the check valve 14 to the pipe 11a. A surge valve (hereinafter referred to as ASV) 16 is provided. Further, a flow rate measuring device 17 is provided in the pipe 11 a downstream from the connection portion with the recirculation pipe 15.

  The train T2 is connected in series between the pipe 21a connected to the inlet header H1, the pipe 21b connected to the outlet header H2, and the pipe 21a and the pipe 21b via the pipe 21c. Compressors 22a and 22b. These compressors 22a and 22b are driven coaxially by a driving machine 23 comprising a motor or a steam turbine.

  In this train T2, a check valve 24 is provided in the pipe 21b, a recirculation pipe 25a is connected from the pipe 21c to the pipe 21a, and a recirculation pipe is connected from the pipe 21b upstream of the check valve 24 to the pipe 21c. 25b is connected, the recirculation pipe 25a is provided with an ASV 26a, and the recirculation pipe 25b is provided with an ASV 26b. Further, a flow rate measuring device 27a is provided in the pipe 21a downstream from the connection portion with the recirculation piping 25a, and a flow measurement device 27b is provided in the piping 21c downstream from the connection portion with the recirculation piping 25b. Yes.

  Thus, in the parallel operation load distribution system of the compressor in the present embodiment, the pipes 11a and 11b and the pipes 21a to 21c are connected in parallel, and the compressor 12 and the compressors 22a and 22b are connected in parallel. The compressor 22a and the compressor 22b are connected in series in two stages, and a plurality of such compressors 12, 22a, 22b are controlled and operated in parallel as described later, and the load is distributed.

  Here, as a minimum configuration example, two series of trains T1 and T2 are connected in parallel and two compressors 22a and 22b are connected in series. However, three or more series of trains are connected in parallel. You may connect and you may connect three or more compressors in series.

  Next, the configuration of the control device will be described. As a configuration of a control device that controls all the trains T1 and T2, a pressure controller (hereinafter referred to as a PC) 31, a calculator 32 (selection unit, selection process), and a calculator 33 are provided. Further, as a configuration of a control device that performs control on the train T1, an anti-surge controller (hereinafter referred to as UIC) 41, a calculator 42 (calculation unit, calculation process), and a load distribution controller (hereinafter referred to as LSC) 43 (control unit, Control step), a setting device 44, and a speed controller (hereinafter referred to as SC) 45. In addition, as a configuration of the control device that controls the train T2, the UIC 51a, the UIC 51b, the computing units 52a to 52c (calculating unit, computing process), the LSC 53 (control unit, controlling process), the setting unit 54, and SC55 And have.

  In the train T1, the UIC 41 controls the opening degree of the ASV 16 based on the flow rate x measured by the flow rate measuring device 17, and circulates the compressed gas discharged from the compressor 12 from the pipe 11b to the pipe 11a to prevent a surge. doing. Also in the train T2, the UIC 51a controls the opening degree of the ASV 26a based on the flow rate x measured by the flow rate measuring device 27a, and circulates the compressed gas discharged by the compressor 22a from the piping 21c to the piping 21a. The surge is prevented, and the UIC 51b controls the opening degree of the ASV 26b based on the flow rate x measured by the flow rate measuring device 27b, and circulates the compressed gas discharged from the compressor 22b from the pipe 21b to the pipe 21c. Prevents surge.

In the train T1, the computing unit 42 calculates the process variable LB _PV based on the flow rate x measured by the flow rate measuring device 17. Also in the train T2, the computing unit 52a calculates the process variable LB _PV based on the flow rate x measured by the flow rate measuring device 27a, and the computing unit 52b is based on the flow rate x measured by the flow rate measuring device 27b. The process variable LB _PV is calculated.

Here, a method for calculating the process variable LB _PV will be described with reference to FIG. FIG. 2 shows a performance curve of the compressor.

In the train T1, the performance curve of the compressor 12 is registered in the computing unit 42. A plurality of operating points with the highest operating efficiency are obtained in advance from the performance curve, and the obtained operating points are linearly interpolated. A curve obtained by linear interpolation is set as an efficiency line. When the flow rate (Flow rate) at the operating point of the compressor 12 is x and the head (Head) is y, the relative distance D from the current operating point (x, y) to the efficiency curve is calculated, and the calculated relative The distance D is converted into an absolute value to calculate the efficiency distance Δ, and the calculated efficiency distance Δ is used as the process variable LB _PV . This efficiency distance Δ is treated as a correlation value that correlates with a real efficiency η described later.

When the efficiency point on the efficiency curve relative to the current operating point (x, y) is (x ₂ , y), the relative distance D and the efficiency distance Δ are expressed by the following equations (1) and (2). . In FIG. 2, the surge limit point (x ₁ , y) on the surge limit curve relative to the current operating point (x, y) is also shown.

D = 1−x ₂ / x (1)
Δ = | D | (2)

Similarly, in the train T2, the performance curve of the compressor 22a is registered in the computing unit 52a, and the efficiency curve is set in advance. Based on the current operating point (x, y) of the compressor 22a, the relative value is calculated. The distance D and the efficiency distance Δ are calculated, and the calculated efficiency distance Δ is set as the process variable LB _PV . In addition, the performance curve of the compressor 22b is registered in the calculator 52b, and the efficiency curve is preset. The relative distance D and the efficiency distance Δ are calculated based on the current operating point (x, y) of the compressor 22b, and the calculated efficiency distance Δ is used as the process variable LB _PV .

In the train T1, the process variable LB _PV (efficiency distance Δ) calculated by the above-described method is output from the computing unit 42 to the LSC 43 and the computing unit 32. In the train T2, the compressors 22a and 22b are arranged in multiple stages. Since they are connected in series, the computing unit 52c selects the maximum value from the plurality of process variables LB _PV (efficiency distance Δ) calculated by the above-described method, and selects the selected value as a new process variable LB _PV ( The efficiency distance Δ) is output from the computing unit 52c to the LSC 53 and the computing unit 32. That is, the calculators 42 and 52c calculate the process variable LB _PV (efficiency distance Δ) for each of the trains T1 and T2 (the pipes 11a and 11b and the pipes 21a to 21c).

The computing unit 32 selects either the maximum value, the average value, or the minimum value of the plurality of process variables LB _PV (efficiency distance Δ) output from the computing units 42 and 52c, and selects the selected process variable LB _PV ( The efficiency distance Δ) is output to the computing unit 33 as the set point LB _SP (selected value). When there is another train, one of the maximum value, the average value, and the minimum value is selected including the process variable LB _PV (efficiency distance Δ) output from the train. Here, any of the maximum value, the average value, and the minimum value may be selected, but it is desirable to select the minimum value.

The computing unit 33 converts the set point LB _SP (efficiency distance Δ) output from the computing unit 32 into the original relative distance D, and uses the converted original relative distance D as the new set point LB _SP as LSC 43 and LSC 53. Output to. That is, the same relative distance D is given as a new set point LB _SP for the LSC 43 of the train T1 and the LSC 53 of the train T2. If there is another train, the same set point LB _SP (relative distance D) is also output to the LSC of that train.

In the train T1, the LSC 43 converts the current process variable LB _PV (efficiency distance Δ) output from the calculator 42 into the original relative distance D, and outputs the converted original relative distance D and the calculator 33. Based on the set point LB _SP (relative distance D) that is the set value, PI control is performed, and the control value CR _LB is output to the setter 44. Also in the train T2, the LSC 53 converts the current process variable LB _PV (efficiency distance Δ) output from the calculator 52c into the original relative distance D, and converts the converted original relative distance D and the calculator 33 from PI control is performed based on the set point LB _SP (relative distance D) that is the output set value, and the control value CR _LB is output to the setter 54. This control value CR _LB is for controlling the rotational speed of the driving machines 13 and 23 described later. Note that the calculator 42 and the calculator 52 c may convert the process variable LB _PV (efficiency distance Δ) into the original relative distance D before outputting to the LSC 43 and LSC 53.

  In this way, the LSCs 43 and 53 are controlled so that all the compressors 12, 22a and 22b converge to the selected relative distance D.

PC31, based on the pressure PV _P measured by the pressure meter 10 provided in the inlet header H1, and outputs the set control values CR _MC 44 and setter 54 for raising to a desired pressure. If there is another train outputs a control value CR _MC to setter the train. The pressure meter is provided 10 to the outlet header H2, on the basis of the pressure PV _P measured by the pressure meter 10 which is provided herein, setter 44 and setter the control value CR _MC for controlling the desired pressure You may output to 54. The control value CR _MC is for controlling the rotational speed of the drive motor 13 and 23 to be described later.

In the train T1, the setter 44 obtains the sum of the control value CR _LB output from the LSC 43 and the control value CR _MC output from the PC 31, and outputs the sum to the _SC 45 as the control value CR _SC . Also in the train T2, the setter 54 obtains the sum of the control value CR _LB output from the LSC 53 and the control value CR _MC output from the PC 31, and outputs the sum to the _SC 55 as the control value CR _SC .

Then, the train T1, SC45 is the rotational speed PV _S of the drive motor 13 is controlled so that the control value CR _SC outputted from the setting device 44. Also in train T2, SC55 is the rotational speed PV _S of the drive machine 23 is controlled such that the control value CR _SC output from the setter 54.

  As described above, since all the compressors 12, 22a, and 22b are controlled based on the selected efficiency distance Δ (relative distance D), even when the performances of the compressors 12, 22a, and 22b differ, the efficiency distance Δ It converges to the operation point where (relative distance D) becomes equal, and the operation efficiency can be optimized. As a result, load distribution control can be performed regardless of the system configuration such as the number of compression stages and the number of trains.

[Example 2]
The present embodiment is a modification of the first embodiment described above. Therefore, in FIG. 3, the changed part is illustrated, and the same code | symbol is attached | subjected to the equivalent structure.

  In Patent Document 2 and Example 1 described above, in the case of a multistage compression configuration (a configuration in which compressors are connected in series), a relative distance and an efficiency distance are calculated for each single stage to obtain a process variable. In the present embodiment, in the train T2, for the compressors 22a and 22b connected in series, the overall performance curve obtained by integrating them is used, thereby simplifying the configuration of the control device and reducing the process variable selection step. ing.

Specifically, as shown in FIG. 3, the basic configuration of the train T2 is the same as that of the train T2 shown in FIG. 1 of the first embodiment, but based on the flow rate x measured by the flow rate measuring device 27a. While the UIC 51a controls the opening degree of the ASV 26a and the computing unit 52 calculates the process variable LB _PV , the UIC 51b determines the opening degree of the ASV 26b based on the flow rate x measured by the flow rate measuring instrument 27b. It is only controlled and is not used to calculate the process variable LB _PV . Therefore, instead of the arithmetic units 52a, 52b, and 52c shown in FIG. 1, one arithmetic unit 52 (arithmetic unit, arithmetic step) is used in this embodiment.

Therefore, an overall performance curve obtained by integrating the compressors 22a and 22b is registered in the computing unit 52, and an efficiency curve is set in advance, and the current operating point of one compressor 22a among the compressors 22a and 22b ( Based on x, y), a relative distance D and an efficiency distance Δ are calculated (see FIG. 2 described above), and the calculated efficiency distance Δ is used as a process variable LB _PV . Since the subsequent control is the same as that in the first embodiment, description thereof is omitted here.

  In this way, the calculation process of the relative distance and efficiency distance for each single stage and the process variable selection process can be reduced, and the efficiency distance for each train can be directly used for the process variable. As a result, in addition to the effects of the first embodiment, there is no need to perform process design and equipment construction accompanying the increase in the number of stages of the compressor, and data input is simplified, leading to cost reduction.

[Example 3]
As shown in FIG. 3, the compressor parallel operation load distribution system according to the present embodiment includes a plurality of trains T1 and T2 that connect the inlet header H1 and the outlet header H2 in parallel. The inlet header H1 is provided with a pressure measuring device 60 for control described later.

  The train T1 includes a pipe 61a connected to the inlet header H1, a pipe 61b connected to the outlet header H2, and one compressor 62 connected between the pipe 61a and the pipe 61b. The compressor 62 is driven by a driving machine 63 made of a motor or a steam turbine.

  In this train T1, a check valve 64 is provided in the pipe 61b, and a recirculation pipe 65 is connected from the pipe 61b upstream of the check valve 64 to the pipe 61a. A surge valve (hereinafter referred to as ASV) 66 is provided. Further, a flow rate measuring device 67 is provided in the piping 61a downstream from the connection portion with the recirculation piping 65, and a flow measuring device 68 is provided in the piping 61a upstream from the connection portion.

  The train T2 is connected in series between the pipe 71a connected to the inlet header H1, the pipe 71b connected to the outlet header H2, and the pipe 71a and the pipe 71b via the pipe 71c. Compressors 72a and 72b. These compressors 72a and 72b are driven coaxially by a driving machine 73 including a motor or a steam turbine.

  In this train T2, a check valve 74 is provided in the pipe 71b, a recirculation pipe 75a is connected from the pipe 71c to the pipe 71a, and a recirculation pipe is connected from the pipe 71b upstream of the check valve 74 to the pipe 71c. 75b is connected, ASV76a is provided in the recirculation piping 75a, and ASV76b is provided in the recirculation piping 75b. Further, a flow rate measuring device 77a is provided in the pipe 71a downstream of the connection portion with the recirculation piping 75a, and a flow rate measuring device 78 is provided in the piping 71a upstream of the connection portion, and the recirculation piping 75b. A flow rate measuring device 77b is provided in the pipe 71c downstream of the connecting portion.

  Thus, in the compressor parallel operation load distribution system in the present embodiment, the pipes 61a and 61b and the pipes 71a to 71c are connected in parallel, and the compressor 62 and the compressors 72a and 72b are connected in parallel. The compressor 72a and the compressor 72b are connected in series in two stages, and the plurality of compressors 62, 72a, 72b are controlled and operated in parallel as described later, and the load is distributed.

  Here, as a minimum configuration example, two series of trains T1 and T2 are connected in parallel and two compressors 72a and 72b are connected in series. However, three or more series of trains are connected in parallel. You may connect and you may connect three or more compressors in series.

  Next, the configuration of the control device will be described. As a configuration of a control device that controls all the trains T1 and T2, a pressure controller (hereinafter referred to as a PC) 81 and a calculator 82 (selection unit, selection process) are provided. Further, as a configuration of a control device that performs control on the train T1, an antisurge controller (hereinafter referred to as UIC) 91, a calculator 92 (calculation unit, calculation process), and a load distribution controller (hereinafter referred to as LSC) 93 (control unit, Control step), a setting device 94, and a speed controller (hereinafter referred to as SC) 95. Further, as a configuration of a control device that performs control on the train T2, a UIC 101a, a UIC 101b, a computing unit 102 (calculating unit, computing process), an LSC 103 (control unit, controlling process), a setting device 104, and an SC 105 are provided. Have.

  In the train T1, the UIC 91 controls the opening degree of the ASV 66 based on the flow rate x measured by the flow rate measuring device 67 and circulates the compressed gas discharged from the compressor 62 from the pipe 61b to the pipe 61a to prevent surge. doing. Also in the train T2, the UIC 101a controls the opening degree of the ASV 76a based on the flow rate x measured by the flow rate measuring device 77a, and circulates the compressed gas discharged from the compressor 72a from the piping 71c to the piping 71a. The surge is prevented, and the UIC 101b controls the opening degree of the ASV 76b based on the flow rate x measured by the flow rate measuring device 77b, and circulates the compressed gas discharged from the compressor 72b from the piping 71b to the piping 71c. Prevents surge.

In the train T1, the computing unit 92 calculates the process variable LB _PV based on the flow rate x measured by the flow rate measuring unit 68. Also in the train T2, the computing unit 102 calculates the process variable LB _PV based on the flow rate x measured by the flow rate measuring device 78.

In the present embodiment, the following equation (3) is used to calculate the real efficiency η from the current operating point of the corresponding compressor 62, 72a, 72b for each of the trains T1 and T2 (the pipes 61a, 61b and the pipes 71a-71c). And the calculated real efficiency η is used as the process variable LB _PV .

  η = (inlet flow rate) × (lift) × g / (power consumption) (3)

  In the above formula (3), “inlet flow rate” is the flow rate at the inlet of each of the trains T1 and T2 measured by the flow rate measuring devices 68 and 78, and “consumed power” is the consumed power of the drive units 63 and 73. is there. When the driving machines 63 and 73 are motors, power consumption is calculated from their current values and voltage values, and when they are steam turbines, power consumption is calculated from their steam flow rates. In this embodiment, the inlet header H1 and the outlet header H2 are common to all the trains T1 and T2. Therefore, the “Head” is considered to be constant in each train T1 and T2. “G” is a gravitational acceleration.

Specifically, in the train T1, the computing unit 92 uses the flow rate x measured by the flow rate measuring unit 68 and the like to calculate the real efficiency η by the above equation (3), and uses the calculated real efficiency η as a process variable LB _PV. It is said. Also in the train T2, the computing unit 102 uses the flow rate x measured by the flow rate measuring device 78 and the like to calculate the real efficiency η by the above equation (3), and uses the calculated real efficiency η as the process variable LB _PV .

  Thus, unlike the calculators 42, 52a, and 52b shown in the first embodiment, the calculators 92 and 102 of the present embodiment do not need to register the performance curves of the compressors 62, 72a, and 72b.

In the train T1, the process variable LB _PV (actual efficiency η) calculated by the above-described method is output from the computing unit 92 to the LSC 93 and the computing unit 82. Also in the train T2, the process variable LB _PV (actual efficiency η) calculated by the above-described method is output from the computing unit 102 to the LSC 103 and the computing unit 82.

The calculator 82 selects either the maximum value, the average value, or the minimum value of the plurality of process variables LB _PV (actual efficiency η) output from the calculator 92 and the calculator 102, and selects the selected process variable LB _PV ( The actual efficiency η) is output to the LSC 93 and the LSC 103 as the set point LB _SP (selected value). If there is another train, one of the maximum value, the average value, and the minimum value is selected including the process variable LB _PV (actual efficiency η) output from the train.

That is, the calculator 82 gives the same substantial efficiency η as the set point LB _SP for the LSC 93 of the train T1 and the LSC 103 of the train T2. If there is another train, the same set point LB _SP (actual efficiency η) is output to the LSC of that train.

In the train T1, the LSC 93 is based on the current process variable LB _PV (actual efficiency η) output from the computing unit 92 and the set point LB _SP (actual efficiency η) that is the set value output from the computing unit 82. PI control is performed, and the control value CR _LB is output to the setting device 94. Also in the train T2, the LSC 103 sets the current process variable LB _PV (actual efficiency η) output from the computing unit 102 and the set point LB _SP (actual efficiency η) that is the set value output from the computing unit 82. Based on this, PI control is performed and the control value CR _LB is output to the setting device 104. The control value CR _LB is for controlling the rotational speed of the drive units 63 and 73 described later.

  In this way, the LSCs 93 and 103 are controlled so that all the compressors 62, 72a, 72b converge to the actual efficiency η selected.

PC81, based on the pressure PV _P measured by the pressure measuring device 60 provided in the inlet header H1, and outputs it to the setter 94 and set 104 a control value CR _MC for boosting to a desired pressure. If there is another train outputs a control value CR _MC to setter the train. The pressure measuring device is provided 60 to the outlet header H2, on the basis of the pressure PV _P measured by the pressure measuring device 60 provided herein, setter 94 and setter the control value CR _MC for controlling the desired pressure You may output to 104. The control value CR _MC is for controlling the rotational speed of the drive motor 63, 73 to be described later.

In the train T1, the setter 94 obtains the sum of the control value CR _LB output from the LSC 93 and the control value CR _MC output from the PC 81, and outputs the sum to the _SC 95 as the control value CR _SC . Also in the train T2, the setter 104 obtains the sum of the control value CR _LB output from the LSC 103 and the control value CR _MC output from the PC 81, and outputs the sum to the _SC 105 as the control value CR _SC .

Then, the train T1, SC95 is the rotational speed PV _S of the drive machine 63 is controlled such that the control value CR _SC output from the setter 94. Also in train T2, SC 105 is a rotational speed PV _S of the drive machine 73 is controlled such that the control value CR _SC output from the setter 104.

  As described above, since all the compressors 62, 72a, 72b are controlled based on the selected real efficiency η, even if the performance of the compressors 62, 72a, 72b is different, the operating point at which the real efficiency η is equal. And the operation efficiency can be optimized. As a result, load distribution control can be performed regardless of the system configuration such as the number of compression stages and the number of trains.

  Further, in the first embodiment, the efficiency distance Δ is used as an index of the operation efficiency, whereas in this embodiment, the actual efficiency η is directly handled as a process variable, so that the operation efficiency is clear. Further, it is not necessary to set performance curves of the compressors 62, 72a, 72b in advance.

[Example 4]
The present embodiment is a modification of the above-described third embodiment. Therefore, in FIG. 5B, the changed portion is illustrated, and the same components are denoted by the same reference numerals.

In the third embodiment, for example, when the operating point of the compressor 62 of the train T1 is located at the apex on the efficiency-flow rate curve shown in FIG. 5A, that is, on the flow rate side larger than the maximum efficiency point. In some cases, load distribution control does not function. This is because, as can be seen from FIG. 5A, the efficiency decreases as the flow rate increases on the flow rate side greater than the maximum efficiency point. On the flow rate side smaller than the maximum efficiency point, the efficiency increases as the flow rate increases. Therefore, if the rotation speed of the compressor 62 (drive device 63) is increased and the flow rate is increased, the efficiency increases. On the larger flow rate side, the efficiency decreases as the flow rate increases. Therefore, if the rotational speed of the compressor 62 (drive unit 63) is increased and the flow rate is increased, the efficiency is decreased (FIG. 5 ( see arrow a _b in a)).

Accordingly, in this embodiment, such as arrow A _b, in order to prevent the operation of lowering the efficiency, it is provided with a switch 96 for performing the switching step of switching the sign of the positive and negative control values CR _LB. The switch 96 is configured so that the current operating point of the compressor 62, that is, the current flow rate x measured by the flow rate measuring device 68 is on the flow side larger than the flow rate at the maximum efficiency point of the efficiency-flow curve, or and comparing whether the following flow side, when in the large flow rate side, a direction control flag LB _F for switching the control direction to output to LSC93. The flow rate at the maximum efficiency point may be obtained in advance based on an efficiency-flow rate curve as shown in FIG.

In the LSC 93, when the direction control flag LB _F is set, that is, when the flow rate is higher than the flow rate at the maximum efficiency point, the control direction by the LSC 93 is switched (specifically, the control value CR _LB In order to increase the efficiency, control is performed to reduce the rotational speed of the compressor 62 (drive unit 63) (see arrow Aa in FIG. _5A ). On the other hand, when the direction control flag LB _F is down, that is, when in the flow following the flow side of the maximum efficiency point, the way has (specifically not switch the control direction of LSC93, control value CR _In order to increase the efficiency, control is performed to increase the rotational speed of the compressor 62 (drive unit 63). Since the subsequent control is the same as that in the third embodiment, description thereof is omitted here.

  Thus, since the control direction of the rotation of the compressor 62 (drive unit 63) is switched so as to increase the efficiency according to the flow rate, the control direction of the LSC 93 is switched, in other words, the control direction of the rotation with respect to the efficiency. Therefore, in addition to the effects of the third embodiment, load distribution can be performed correctly at any flow rate.

  Although the train T1 is illustrated here, the present invention can also be applied to the train T2 in which the compressors 72a and 72b are connected in series.

  The present invention is suitable for parallel operation when a plurality of compressors are connected in parallel.

10 Pressure measuring instrument 11a, 11b, 21a, 21b, 21c Piping 12, 22a, 22b Compressor 13, 23 Driver 14, 24 Check valve 15, 25a, 25b Recirculation piping 16, 26a, 26b Anti-surge valve 17, 27a 27b Flow rate measuring device 31 Pressure controller 32, 33 Calculator 41, 51a, 51b Anti-surge controller 42, 52, 52a, 52b, 52c Calculator 43, 53 Load distribution controller 44, 54 Setter 45, 55 Speed controller 60 Pressure measuring instrument 61a, 61b, 71a, 71b, 71c Piping 62, 72a, 72b Compressor 63, 73 Driver 64, 74 Check valve 65, 75a, 75b Recirculation piping 66, 76a, 76b Anti-surge valve 67, 77a, 77b Flow meter 68, 78 Flow rate measuring device 81 Pressure controller 82 Calculator 91, 101a, 101b Anti-surge controller 92, 102 Calculator 93, 103 Load distribution controller 94, 104 Setter 95, 105 Speed controller 96 Switch H1 Inlet header H2 Outlet Header T1, T2 Tren

Claims (12)

One or more compressors each connected to a plurality of pipes connected in parallel;
A controller for operating the plurality of compressors in parallel and distributing the load,
The controller is
For each pipe, a calculation unit for obtaining a correlation value that correlates with the real efficiency or the real efficiency of the compressor of the pipe;
A selection unit that selects, as a selection value, any one of a plurality of the obtained real efficiencies or a maximum value, an average value, or a minimum value of the correlation values;
And a controller for controlling all of the compressors based on the selected value. In the compressor parallel operation load distribution system according to claim 1,
For each of the compressors, the calculation unit obtains an efficiency curve in advance by linearly interpolating a plurality of operating points with the highest operating efficiency from the performance curve of the compressor, and calculates the efficiency from the current operating point of the compressor. While calculating the relative distance to the curve, the efficiency distance obtained by converting the relative distance into an absolute value, and using the efficiency distance as the correlation value,
The control unit converts the selected value to the original relative distance, and controls all the compressors so as to converge to the converted original relative distance. system. In the compressor parallel operation load distribution system according to claim 2,
When a plurality of the compressors are connected in series to the pipe,
The operation unit selects a maximum value of a plurality of the efficiency distances for the plurality of compressors connected in series, and uses the selected maximum value as the correlation value. . In the compressor parallel operation load distribution system according to claim 2,
When a plurality of the compressors are connected in series to the pipe,
The calculation unit obtains a performance curve obtained by integrating performance curves of the plurality of compressors connected in series with respect to the plurality of compressors connected in series, and determines a plurality of operating points with the highest operating efficiency from the performance curve. An efficiency curve is obtained in advance by linear interpolation, and a relative distance from the current operating point of one of the compressors connected in series to the efficiency curve is calculated, and the relative distance An efficiency distance obtained by converting the absolute value into an absolute value and using the efficiency distance as the correlation value. In the compressor parallel operation load distribution system according to claim 1,
The calculation unit obtains the substantial efficiency from the current operating point of the compressor of the pipe for each pipe,
The controller is configured to control all the compressors so as to converge to the substantial efficiency at which the selected value is selected. In the parallel operation load distribution system of the compressor according to claim 5,
And a switching unit that switches between positive and negative signs of the selected value,
The switching unit obtains in advance the flow rate at the maximum efficiency point at which the efficiency is maximum from the compressor efficiency-flow rate curve for the pipe, and the flow rate at the current operating point of the compressor is the maximum flow rate. A parallel operation load distribution system for compressors, wherein the sign of the selected value is switched to negative when the flow rate is greater than the efficiency point flow rate, and the sign of the selection value is switched to positive when the flow rate is less than or equal to the maximum efficiency point flow rate. For a compressor connected to one or more pipes connected in parallel with each other, in a parallel operation load distribution method for a compressor that performs load distribution while simultaneously operating the plurality of compressors,
For each pipe, a calculation step for obtaining a correlation value that correlates with the real efficiency or the real efficiency of the compressor of the pipe; and
A selection step of selecting, as a selection value, any one of a plurality of obtained real efficiencies or a maximum value, an average value, or a minimum value of the correlation values;
And a control step of controlling all the compressors based on the selected value. The parallel operation load distribution method for compressors according to claim 7,
In the calculation step, for each of the compressors, an efficiency curve is obtained in advance by linearly interpolating a plurality of operating points with the highest operating efficiency from the performance curve of the compressor, and the efficiency is calculated from the current operating point of the compressor. While calculating the relative distance to the curve, the efficiency distance obtained by converting the relative distance into an absolute value, and using the efficiency distance as the correlation value,
The control step converts the selected value selected into the original relative distance, and controls all the compressors so as to converge to the converted original relative distance. Method. The parallel operation load distribution method for compressors according to claim 8,
When a plurality of the compressors are connected in series to the pipe,
The calculation step includes selecting a plurality of maximum values of the efficiency distances for the plurality of compressors connected in series, and using the selected maximum values as the correlation value. . The parallel operation load distribution method for compressors according to claim 8,
When a plurality of the compressors are connected in series to the pipe,
The calculation step obtains a performance curve obtained by integrating performance curves of the plurality of compressors connected in series with respect to the plurality of compressors connected in series, and determines a plurality of operating points with the highest operating efficiency from the performance curve. An efficiency curve is obtained in advance by linear interpolation, and a relative distance from the current operating point of one of the compressors connected in series to the efficiency curve is calculated, and the relative distance An efficiency distance obtained by converting the absolute value into an absolute value and using the efficiency distance as the correlation value. The parallel operation load distribution method for compressors according to claim 7,
The calculation step calculates the substantial efficiency from the current operating point of the compressor of the pipe for each pipe,
In the control step, all the compressors are controlled so as to converge to the substantial efficiency that is the selected value that has been selected. The parallel operation load distribution method for compressors according to claim 11,
And a switching step of switching between positive and negative signs of the selected value,
In the switching step, the flow rate at the maximum efficiency point at which the efficiency is maximized is determined in advance from the efficiency-flow rate curve of the compressor for the piping, and the flow rate at the current operating point of the compressor is the maximum flow rate. A method for distributing a parallel operation load of a compressor, wherein the sign of the selected value is switched to negative when the flow rate is greater than the efficiency point flow rate, and the sign of the selection value is switched to positive when the flow rate is less than or equal to the flow rate at the maximum efficiency point.

Images