JPH04148100A - Control device for compressor - Google Patents

Abstract

PURPOSE:To enhance the reliability of a compressor and to reduce the power of a drive unit by computing a pressure boost-up ratio of the compressor so as to obtain an opration signal for an adjusting velve with respect to a predetermined set value in accordance with the characteristic of the compressor, so that the compressor is prevented from falling into a choking range and the pressure is boosted up efficiently. CONSTITUTION:An inlet pressure and an outlet pressure of a compressor 1 are detected by first and second pressure detectors 22, 21, and are delivered to a subtracter 23 which accordingly computes a pressure boost-up ratio that is then delivered to an adjuster 25. Further, an inlet flow rate of the compressor 1 is detected by a flow rate detector 13 and is delivered to a function generator 24 which delivers a predetermined set value in accordance with the characteristic of the compressor 1 to the adjuster 25. The adjuster 25 receives the output from the function generator 24 as a set value signal and a pressure boost-up ratio as a control signal, and delivers an operation signal for an adjusting valve 20 so that the compressor 1 is prevented from falling into a choking range, and the pressure is efficiently boosted up in order to adjust the opening degree of the adjusting valve 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a compressor applied to gas pipelines, ammonia plants, and the like.

[Prior Art] The conventional technology will be explained using a compressor for a gas pipeline compressor station as an example.

Fig. 5 shows a plant flow diagram of a conventional gas pipeline compres- sion system.

The upstream compressor station 3 and the target compressor station 30 are connected by a pipeline 1o. The target compressor station 3° and the downstream compressor station 6 are connected by a pipeline 11.

When the compressor 1 of the target compressor stage 30 is stopped, the bypass line 12 from the upstream compressor stage 3 to the downstream compressor stage engine 6
Gas can flow through. Compressor l is drive machine 2
Driven by. As the drive machine 2, for example, a gas turbine, a steam turbine, etc. are used. When the compressor 1 is started, gas enters the compressor 1 through the piping 17 and the saxiland drum 5, and flows to the pipeline 711 through the extraction piping 18. A check valve 4 is installed in the bypass line 12, and when compression Ill is started, the pressure in the extraction pipe 18 becomes higher than the pressure in the inlet pipe 17, the check valve 4 is fully closed, and the bypass The flow rate through line 12 is zero.

In addition, gas can be circulated from the outlet of the compressor 1 to the satanyong drum 5 through the pipe 7, and the compressor 1
The flow rate controller 9 is set so that the inflow flow rate does not fall below a certain value.
Operate the control valve 8 with. This prevents the surging phenomenon of the compressor l.

Next, FIG. 6 shows the pressure distribution inside the pipeline. The broken line in the figure indicates the target compres- sion 3.
This is the pressure distribution when zero is stopped. At this time, the pressure in the inlet pipe 17 of the target compressor station 30 and the pressure in the outlet pipe 1B 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 as shown by the solid line in FIG. 6 is shown. Inlet piping 1 for target compressor station SOYON 30
7 to the pressure P2 of the outlet pipe 18.

Next, with reference to the seventh cabinet and FIG. 8, the behavior of the compressor l of the target compressor/7 suspension station 30 from before to after startup will be explained.

First, in FIG. 8, the horizontal axis shows time and the vertical axis shows state quantities (pressure, flow rate, etc.).

Up to point A, the compressor 1 is stopped 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. ing. When the compressor 1 is started from this state and the rotation speed is increased, the compressor flow rate gradually increases,
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 can no longer be held at the set value and begins to increase. After that, point B is when the rotational speed reaches the rated value. If you look at the performance curve of the compressor from point A to point B, it will look like Figure 7.

Since the capacity of the pipeline 10.11 is large, the outlet pressure continues to gradually increase even after the rotational 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. 7, the rotational 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 surging region operation.

Furthermore, contour lines (dashed lines) of compressor efficiency (η+1) are shown on FIG.

-i is the rated point) (point C) has the highest efficiency, and the further away from it, the lower it becomes. At point B, the rotational speed is at the rated speed, but the efficiency is only about 20 to 30%, which is low efficiency. It can be seen that the rate increases as the point approaches C. As shown in Figure 8, the power consumption at this time reaches its maximum value at the lowest efficiency point B at the rated rotation speed,
After that, it gradually decreased and reached the rated value (point C).

Problem to be solved by the invention C] Looking at the behavior of the power consumption in Fig. 8, it increases significantly after point B''' and reaches a peak value. At this time, the capacity (output) of the drive machine 2 exceeds 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 must 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.

Also, looking at the behavior of the compressor at startup in Figure 7,
Since the rotation speed enters the choking region before and after reaching the rated value, and the capacity of the pipeline 11 is large,
After the rotational speed reaches the rated number, the boost ratio increases only gradually, and as a result, there is a risk of damage to the compressor due to operation in the choking region for a long time.

[Means to solve the problem]

The present invention takes the following measures to solve the above problems.

That is, as a control device for a compressor, in the process of operating the compressor to increase the pressure of gas, a first pressure detector detects the population pressure of the compressor, and a second pressure detector detects the outlet pressure of the compressor. a pressure detector, a divider that inputs the output signal of the first pressure detector and the output signal of the second pressure detector, a flow rate detector that detects the suction flow rate to the compressor, and the same flow rate. A function generator that inputs the output signal of the detector 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 is installed at the inlet of the compressor. A control valve is provided to input the output signal of the pressure regulator.

[Effect]

With 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. Also, the inlet flow rate of the compressor is detected by a flow rate detector and sent to the 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 pressurizer does not enter the navigating region and boosts the pressure efficiently. The signal is then sent to the control valve.

The control valve adjusts the valve opening according to human power.

In this way, the compressor does not enter the choking region and
Regular road operation can now be achieved without a significant increase in power consumption.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is an overall configuration system diagram, and FIGS. 3 to 4 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. The output of the flow rate detector 13 is sent to a controller 25 via a function generator 24. Further, a control valve 20 is provided in the artificial pipe 17. Divider 23
The output is sent to the control valve 20 via the controller 25.

In the above configuration, the first and second pressure detectors 22
．． At 21, the inlet pressure and outlet pressure of the compressor 1 are detected and sent to the divider 23. A step-up ratio is calculated by the divider 23 and sent to the U@ moderator 25. Further, the inlet flow rate of the compressor 1 is detected by the flow rate detector 13 and sent to the function generator 24 . The function generator 24 compresses! l! A predetermined setting value corresponding to the characteristic of the controller 1 is output, and the signal is sent to the controller 25.

The controller 25 inputs the output from the function generator 24 as a set value signal, inputs the boost ratio from the divider 23 as a control signal,
A control signal for the control valve 20 is output so that the compressor 1 does not enter a choking region and the pressure is increased efficiently, and the signal is sent to the control valve 20. The control valve 20 adjusts the valve opening depending on the input.

FIG. 2 shows the evaluation function of the function generator 24.

The behavior of the compression Ill at startup will be explained with reference to FIGS. 3 and 4. In FIG. 4, 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 compression Ill is started from this state and the rotational speed is increased, the inlet flow rate of the compressor 1 gradually increases, and the pressure increase ratio also gradually increases. Point 6 is the point in time when the artificial 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 boost ratio becomes smaller than the set value which is the output of the function generator 24, the opening degree of the control valve 2o gradually becomes smaller by the controller 25, and the inlet pressure of the compressor 1 becomes smaller. Therefore, the pressure increase ratio increases along the pressure control setting number function (evaluation function) shown in FIG.

Point K is the point in time when the rotation 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 output of the compressor 1 gradually increases, and while the boost ratio is kept constant by the controller 25, the opening degree of the control valve 20 gradually increases. This is when the set value of the controller 25, which is the output signal of the regulator 24, and the boost ratio match. At this time, the control valve 20 is fully opened, and the pressure increase ratio of the compressor increases again.

FIG. 3 shows the performance curve of the compressor 1 from point A until reaching the rating.

From FIG. 3, it can be seen that the vehicle is operated while avoiding the choking region from point H to point H.

Furthermore, at this time, from Figure 4, the power consumption does not show a peak and is kept lower than before, and the efficiency is up to about 20%.
It's getting better.

As described above, the compressor 1 can reach its rated operation without entering the choking region and without significantly increasing power consumption.

〔Effect of the invention〕

As explained above, according to the present invention, the motor is operated without entering the choking region.

Furthermore, the amount of power consumption exceeding the rated value can be reduced to less than half of the conventional method.

Therefore, reliability of the compressor is improved. In addition, the power required for the driving 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 of the embodiment, and Fig. 3 is a diagram of the performance curve and operating trajectory of the compressor of the embodiment. , Fig. 4 is a diagram showing changes in pressure, flow rate, valve opening degree, etc. over time in the same example, Fig. 5 is an overall configuration system diagram of the conventional example, and Fig. 6 is the pressure distribution of the pipeline in the same conventional example. FIG. 7 is a diagram showing the performance curve and operating locus of the compressor of the conventional example, and FIG. 8 is a diagram showing temporal changes in pressure, flow rate, valve opening degree, etc. of the conventional example. 30...Target conbrella suspension silane, 1...Compressor, 2...Driver, 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 pipeline, 11... Downstream Side pipeline, ]2...
・Bypass line, 13...Flow rate detector, 17.
...Piping, 18...Piping, 20...Pressure control valve, 21...Second pressure detector, 22...First
pressure detector, 23... divider, 24...
Function generator, 25...controller. Agent: Patent Attorney Akigai Sakama (2 people) Figure 2 Figure 4

Claims (1)

[Claims] In the process of increasing the pressure of gas by operating a compressor, a first pressure detector detects the inlet pressure of the compressor, a second pressure detector detects the outlet pressure of the compressor, and the first pressure detector detects the inlet pressure of the compressor.
a divider that inputs the output signal of the pressure detector and the output signal of the second pressure detector; a flow rate detector that detects the suction flow rate to the compressor; and a divider that inputs the output signal of the second pressure detector; A function generator that 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 receives the output signal of the pressure regulator. A control device for a compressor, comprising: a control valve for input.