JPH04370397A - Control device for compressor - Google Patents

Abstract

PURPOSE:To operate a compressor without entering a choking region by generating compression ratio, calculating an inlet/outlet pressure of the compressor by a divider, to serve as a control signal in a pressure adjusting meter, and controlling an adjusting valve set up in an inlet side with an output, in accordance with characteristic of the compressor in a function generator from a rotational speed, as a preset value signal. CONSTITUTION:At the time of starting a compressor 1, when a rotational speed is increased, an inlet flow of the compressor 1 is gradually increased, and an output of a divider 23, that is, step-up ratio is also gradually increased. When the inlet flow is increased to a preset value, an adjusting valve 8 is throttled and held to the preset value in a flow adjusting meter 9, but when an opening of the adjusting valve 8 is decreased to zero, the flow can not be held to the preset value to start again to increase, and the step-up ratio is decreased to be smaller than the preset value of an output of a function generator 24 to decrease an input pressure of the compressor 1 by gradually decreasing an opening of an adjusting valve 20 by a pressure adjusting meter 25. Consequently, the step-up ratio is increased along a step-up ratio control preset value function. After the above, when the rotational speed is held to a rated value, an output pressure is gradually increased to fixedly hold the step-up ratio by the pressure adjusting meter 25.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor control device applied to gas pipelines, ammonia plants, etc.

0002

2. Description of the Related Art Conventional technology will be explained using a compressor in a compressor station of a gas pipeline as an example. FIG. 6 shows a plant flow diagram of a conventional gas pipeline compressor station.

[0003] The upstream compressor station 3 and the target compressor station 30 are connected by a pipeline 10. The target compressor station 30 and the downstream compressor station 6 are connected to the pipeline 11
connected with.

When the compressor 1 of the target compressor station 30 is stopped, gas can flow through the bypass line 12 from the upstream compressor station 3 to the downstream compressor station 6. The compressor 1 is driven by a drive machine 2. As the drive machine 2,
For example, gas turbines, steam turbines, etc. are used. When the compressor 1 is started, gas enters the compressor 1 through the pipe 17 and the suction drum 5, and flows into the pipeline 11 through the extraction pipe 18. A check valve 4 is installed in the bypass line 12, and when the compressor 1 is started, the pressure in the extraction pipe 18 becomes higher than the pressure in the inlet pipe 17, and the check valve 4 is fully closed. Bypass line 1
The flow rate through 2 becomes zero.

Further, gas can be circulated from the outlet of the compressor 1 to the suction drum 5 through a pipe 7, and a flow rate controller 9 is used to control a control valve 8 so that the inflow flow rate of the compressor 1 does not fall below a certain value. operate. This prevents the surging phenomenon of the compressor 1.

Next, FIG. 7 shows the pressure distribution inside the pipeline. The broken line in the figure is the pressure distribution when the target compressor station 30 is stopped. At this time, the pressure in the inlet pipe 17 and the pressure in the outlet pipe 18 of the target compressor station 30 are almost the same, the check valve 4 is fully open, and gas is flowing through the bypass line 12. After the compressor 1 is started, a pressure distribution like the solid line in FIG. 7 is shown. At the target compressor station 30, the pressure P1 of the inlet pipe 17 to the pressure P2 of the outlet pipe 18
has been boosted to.

Next, the behavior of the compressor 1 of the target compressor station 30 from before to after startup will be explained with reference to FIGS. 8 and 9.

First, in FIG. 9, the horizontal axis represents time, and the vertical axis represents the state quantity (
pressure, flow rate, etc.). The compressor 1 is stopped up to point A, and the outlet pressure and inlet pressure are equal. At this time, the compressor flow rate is zero and is smaller than the set value of the flow rate controller 9, so the opening degree of the control valve 8 is fully open. When the compressor 1 is started from this state and the rotational speed is increased, the compressor flow rate gradually increases and the ratio of the outlet pressure to the inlet pressure (pressure increase ratio) also gradually increases. Point B' is the point at which the compressor flow rate becomes the same as the set value of the flow rate controller 9, and the flow rate controller 9 gradually reduces the opening degree of the control valve 8 to maintain the flow rate at the set value. When reaching point B'', the opening degree of the control valve 8 becomes zero, the flow rate cannot be maintained at the set value, and the flow rate begins to increase.Then, the point when the rotation speed reaches the rated value is point B. .If you look at the performance curve of the compressor from point A to point B, it will look like Figure 8.

[0009] Since the capacities of the pipelines 10 and 11 are large, the outlet pressure continues to gradually increase even after the rotation speed reaches the rated value, and conversely, the inlet pressure continues to gradually decrease and eventually approaches the rated value. . At this time, as shown in FIG. 8, the rotation speed is constant at the rated value and the boost ratio gradually increases, so the flow rate gradually decreases and approaches the rated point C. The period between point B''' and point D is in the choking region operation.

[0010] Furthermore, the compressor efficiency (ηH
) shows the contour lines (dashed lines). Generally, the efficiency is highest near the rated point (point C), and the further away from it, the lower it becomes. At point B, the rotation speed is rated, but the efficiency is 20-3
It is only about 0%, which is low efficiency. It can be seen that the efficiency increases as the point approaches C. As shown in FIG. 9, the power consumption at this time shows a maximum value at the lowest efficiency point B at the rated rotation speed, and then gradually decreases to reach the rated value (point C).

[0011]

[Problems to be Solved by the Invention] Looking at the behavior of power consumption in FIG. 9, it shows a large increase after point B''' and reaches a peak value at point B. At this time, the capacity (output) of the drive device 2 needs to be greater than this peak value. In the conventional method, this peak value is considerably larger than the rated power consumption, and the capacity of the drive machine needs to be large enough to match this peak value. If the peak value of power consumption can be reduced by some method, the capacity of the drive machine can be reduced, resulting in cost reduction.

[0012] Furthermore, looking at the behavior of the compressor at startup in Fig. 8, it is found that the rotation speed enters the choking region before and after reaching the rated value, and since the capacity of the pipeline 11 is large, the rotation speed does not reach the rated value. After reaching this point, the boost ratio increases only gradually, and as a result, the compressor may be damaged by operating in the choking region for a long time.

[0013]

[Means for Solving the Problems] In order to solve the above problems, the present invention has a first pressure detector that detects the inlet pressure of the compressor in the process of operating the compressor to boost the pressure of gas. a second pressure detector that detects the outlet pressure of the compressor; a divider that inputs the output signal of the first pressure detector and the output signal of the second pressure detector; a rotation speed detector that detects the rotation speed of the engine; a function generator that inputs the output signal of the rotation speed detector and outputs a predetermined set value; and a function generator that receives the output signal of the function generator and the output signal of the divider. The compressor is characterized by comprising a pressure regulator for input, and a control valve installed at the inlet of the compressor for inputting the output signal of the pressure regulator.

[0014]

According to the above means, the inlet pressure and outlet pressure of the compressor are detected by the first and second pressure detectors and sent to the divider. The boost ratio is calculated by the divider and sent to the controller. In addition, the rotation speed of the compressor is detected by a rotation speed detector.
Sent to function generator. The function generator outputs a predetermined set value according to the characteristics of the compressor, and the signal is sent to the controller. The controller uses the output from the function generator as a set value signal, inputs the boost ratio from the divider as a control signal, and outputs a control valve operation signal so that the compressor does not enter the choking region and increases the pressure efficiently. , the signal is sent to the control valve. The control valve adjusts the valve opening depending on the input. In this way, the compressor is able to reach rated operation without entering the choking region and without significantly increasing power consumption.

[0015]

[Embodiment] An embodiment of the present invention will be explained with reference to FIGS. 1 to 5. FIG. 1 is an overall configuration system diagram, and FIGS. 2 to 5 are action explanatory diagrams. Note that the parts explained in the conventional example are given the same numbers and the explanation thereof is omitted, and the explanation will mainly be given to the parts related to the present invention.

In FIG. 1, a first pressure detector 22 is provided at the inlet to detect the inlet pressure of the compressor 1, and its output is sent to a divider 23. Further, a second pressure detector 21 is provided in the extraction pipe 18 to detect the outlet pressure, and its output is sent to the divider 23. Further, the output of the rotation speed detector 14 is sent to a controller 25 via a function generator 24. Further, the inlet pipe 17 is provided with a control valve 20 . The output of the divider 23 is sent to the control valve 20 via a controller 25.

In the above configuration, the inlet pressure and outlet pressure of the compressor 1 are detected by the first and second pressure detectors 22 and 21 and sent to the divider 23. The boost ratio is calculated by the divider 23 and sent to the controller 25. Further, the rotation speed of the compressor 1 is detected by the rotation speed detector 14, and the rotation speed of the compressor 1 is detected by the function generator 24.
sent to. The function generator 24 outputs a predetermined set value according to the characteristics of the compressor 1, and the signal is sent to the controller 25. The controller 25 uses the output from the function generator 24 as a set value signal, inputs the boost ratio from the divider 23 as a control signal, and adjusts the control valve 20 so that the compressor 1 does not enter the choking region and increases the pressure efficiently. An operation signal is output, and the signal is sent to the control valve 20. The control valve 20 adjusts the valve opening depending on the input.

FIGS. 2 and 3 show evaluation functions of the function generator 24. The behavior of the compressor 1 at startup will be explained with reference to FIGS. 4 and 5. In FIG. 5, the compressor 1 is stopped at point A, and the inlet pressure and outlet pressure of the compressor 1 are equal. Since the inlet flow rate of the compressor 1 is zero, the control valve 8 is fully open. Furthermore, since the pressure increase ratio is 1.0, the control valve 20 is also fully open.

When the compressor 1 is started from this state and the rotational speed is increased, the flow rate at the inlet of the compressor 1 gradually increases, and the pressure increase ratio also gradually increases. Point G is the point in time when the inlet flow rate of the compressor 1 becomes the same as the set value, and the opening degree of the control valve 8 is gradually reduced by the flow rate controller 9 to maintain the flow rate at the set value. When the point G' is reached, the opening degree of the control valve 8 becomes zero, the flow rate cannot be maintained at the set value, and the flow rate starts to increase again. At point H, the pressure increase ratio becomes smaller than the set value which is the output of the function generator 24, the opening degree of the control valve 20 is gradually reduced by the controller 25, and the inlet pressure of the compressor 1 is reduced. Therefore, the boost ratio increases along the boost ratio control set value function (evaluation function) shown in FIGS. 2 and 3. K
The point is when the rotational speed of the compressor 1 reaches the rated value. After this, the rotational speed is maintained at the rated rotational speed. At this time,
The outlet pressure of the compressor 1 gradually increases, and while the pressure increase ratio is kept constant by the regulator 25, the pressure at the outlet of the regulator 2 increases.
The opening degree at 0 gradually increases. The L point is when the set value of the controller 25, which is the output signal of the function generator 24, and the boost ratio match. At this time, the control valve 20 is fully opened, and the pressure increase ratio of the compressor begins to increase again. A
FIG. 4 shows the performance curve of the compressor 1 from the point until reaching the rating.

From FIG. 4, it can be seen that the vehicle is operated while avoiding the choking region from point H to point K. Furthermore, at this time, from FIG. 5, the power consumption does not show a peak and is kept lower than before, and the efficiency is improved by about 20% at maximum. As described above, the compressor 1 can reach the rated operation without entering the choking region and without significantly increasing power consumption.

[0021]

As explained above, according to the present invention, the motor can be operated without entering the choking region. Also,
Power consumption can also be reduced to less than half that of conventional methods. Therefore, the reliability of the compressor is improved. In addition, the power required for the drive machine is small, and equipment costs and operating costs are significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is an evaluation function diagram of the function generator according to the flow rate of the same embodiment.

FIG. 3 is an evaluation function diagram of the function generator according to the rotation speed of the same embodiment.

FIG. 4 is a diagram showing a performance curve and an operating trajectory of the compressor of the same example.

FIG. 5 is a diagram showing temporal changes in pressure, flow rate, valve opening degree, etc. in the same example.

FIG. 6 is an overall configuration system diagram of a conventional example.

FIG. 7 is a diagram showing the pressure distribution of the pipeline of the same conventional example.

FIG. 8 is a diagram showing a performance curve and an operating trajectory of the conventional compressor.

FIG. 9 is a diagram showing temporal changes in pressure, flow rate, valve opening degree, etc. of the conventional example.

[Explanation of symbols]

30 target compressor station, 1 compressor, 2 drive machine, 3 upstream compressor station, 4 check valve, 5 suction tank, 6 downstream compressor station, 7 piping, 8 flow rate control valve, 9 flow rate controller, 10 upstream side pipeline, 11 downstream pipeline, 12 bypass line, 13 flow rate detector, 14 rotation speed detector, 17 piping, 18 piping, 20 pressure control valve, 21 second pressure detector, 22 first pressure detector , 23 divider, 24 function generator, 25 controller.

Claims (1)

[Claims] Claim 1: In the process of operating a compressor to increase the pressure of gas, a first pressure detector detects the inlet pressure of the compressor, a second pressure detector detects the outlet pressure of the compressor; , a divider that inputs the output signal of the first pressure detector and the output signal of the second pressure detector, a rotation speed detector that detects the rotation speed of the compressor, and a rotation speed detector that detects the rotation speed of the compressor. a function generator that inputs an output signal and outputs a predetermined set value; a pressure regulator that inputs the output signal of the function generator and the output signal of the divider; and a pressure regulator that is installed at the inlet of the compressor and that adjusts the pressure. 1. A control device for a compressor, comprising: a control valve for inputting an output signal from a meter.