JP2009007949A - Compression device and its starting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression device capable of starting in a short time without entering an unstable operating state. <P>SOLUTION: When the compression device is started, which has a pressure regulator 9 for adjusting the opening of an inlet guide vane 2 to set the discharge pressure of a turbo compressor 1 closer to its target value and a flow regulator 12 for adjusting the opening of a relief valve 3 to set the discharge flow rate of the turbo compressor 1 closer to its target value, the target value of the discharge flow rate on the flow regulator 12 is set to a value greater than that for regulator operation and the pressure regulator 9 and the flow regulator 12 are operated at the same time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a compression apparatus, and more particularly to a method for starting a compression apparatus using a turbo compressor.

  FIG. 5 shows a configuration of a conventional compression apparatus. A conventional compressor using the turbo compressor 101 includes an inlet guide vane (IGV) 102 that restricts an intake flow path of the turbo compressor 101 and an air discharge valve that discharges compressed gas discharged from the turbo compressor 101 to the outside. (BOV) 103, and includes a pressure transmitter 104 for detecting the pressure in the discharge flow path and a pressure transmitter 105 for detecting the discharge flow rate.

  In this compressor, the opening degree of the inlet guide vane 102 is adjusted so that the discharge pressure of the turbo compressor 101 becomes a set value, the discharge flow rate is monitored, and a surge is caused when the demand for compressed gas decreases. The air discharge valve 103 is opened so that the gas flow rate in the turbo compressor 101 is secured. In the control of the discharge valve 103, the target value of the discharge flow rate changes in proportion to the discharge pressure.

  FIG. 6 shows the starting procedure of the conventional compressor, and FIG. 7 shows the transition of the pressure and flow rate of the discharge gas at the time of starting. The conventional compression apparatus is started from a state in which the inlet guide vane 102 is fully closed and the air discharge valve 103 is fully opened. First, in step S101, the main motor of the turbo compressor 101 is activated, and in step S102, the process waits for the predetermined standby time to elapse and the rotation of the turbo compressor 101 to become stable (point A). In step S103, when the inlet guide vane 102 is opened to a predetermined opening degree, the discharge flow rate increases along the entire amount discharge curve (point A → point B). Further, when the discharge valve 103 is fully closed in step S104, the discharge flow rate is decreased and the discharge pressure is increased (point B → point C). In this state, when the opening degree adjustment of the inlet guide vane 102 is switched to automatic control based on the discharge pressure in step S105, the discharge flow rate changes according to the load (demand) while keeping the discharge pressure constant (point C−). Between points D).

  According to the conventional starting procedure of the compression apparatus as described above, since the time until the inlet guide vane 102 is automatically controlled after the fully closing operation of the discharge valve 103 is relatively long, the time has elapsed. Until this occurs (until the compressor is started), necessary and sufficient compressed gas cannot be supplied to the demand side, and wasteful power will be consumed by venting.

Further, if the air discharge valve 103 is rapidly closed, the discharge pressure rises from the point B to the point C and the discharge flow rate decreases suddenly, which may overshoot the surge region. There is a problem that the start-up time of the compression device becomes long (see the timing chart of FIG. 8).
JP-A-6-346894

  In view of the above-described problems, an object of the present invention is to provide a compression device and a method for starting the compression device that can be started in a short time without the operating state becoming unstable.

  In order to solve the above-described problems, a compression apparatus according to the present invention includes a pressure controller that adjusts an opening degree of an inlet guide vane so that a discharge pressure of a turbo compressor approaches a target value, and a target discharge flow rate of the turbo compressor. It has a flow controller that adjusts the opening degree of the air release valve so as to approach the value, and has a function of simultaneously operating the pressure controller and the flow controller at the time of activation.

  According to this configuration, the air release valve is closed while opening the inlet guide vane, so that the time until the steady operation is reached is short.

  In the compression device of the present invention, the target value of the discharge flow rate may be set to a larger value as the discharge pressure increases.

  According to this configuration, surge can be effectively prevented.

  In the compression device of the present invention, the target value of the discharge flow rate may be set to a larger value at the time of startup than during steady operation.

  According to this configuration, during steady operation, the operating range is set wide in a range that can prevent surges, and at startup, the margin for surges is increased to increase the coefficient of control and start up in a short time. Can be.

  In the compression apparatus of the present invention, the target value at the start of the discharge flow rate may be set to a value obtained by adding a constant value to the target value at the time of steady operation.

  According to this configuration, the target value can be easily switched.

  In addition, according to the present invention, the pressure controller for adjusting the opening of the inlet guide vane so that the discharge pressure of the turbo compressor approaches the target value, and the air discharge so that the discharge flow rate of the turbo compressor approaches the target value. The starting method of the compression apparatus having the flow rate controller for adjusting the opening degree of the valve is a method in which the pressure controller and the flow rate controller are simultaneously operated at the time of starting.

  According to this method, since the air discharge valve is closed while opening the inlet guide vane, the time required to reach steady operation is short.

  Moreover, in the starting method of the compression apparatus of the present invention, the target value of the discharge flow rate may be set to a larger value at the time of starting than at the time of steady operation.

  According to this method, during steady operation, the operable range is set wide within a range where surge can be prevented, and during startup, the margin for surge is increased, so that the control coefficient can be increased and startup can be performed in a short time.

  According to the present invention, the compression device can be started in a short time by operating the pressure controller and the flow controller simultaneously.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a compression apparatus according to one embodiment of the present invention. The compression apparatus of this embodiment compresses gas with the turbo compressor 1.

  This compression device has an inlet guide vane (IGV) 2 that restricts the suction flow path of the turbo compressor 1 and an air discharge valve (BOV) 3 that discharges gas from the discharge flow path to the outside of the system. The turbo compressor 1 is driven by a main motor 4 and includes a current transmitter 5 that measures the drive current of the main motor 1. Further, a pressure transmitter 6 for detecting the discharge pressure of the turbo compressor 1 and a flow rate transmitter 7 for detecting the discharge flow rate of the turbo compressor 1 are provided in the discharge flow path of the compression device.

  The opening degree of the inlet guide vane 2 includes the control output of the current regulator 8 that uses the output of the current transmitter 5 as a control input, and the control output of the first pressure regulator 9 that uses the output of the pressure transmitter 6 as a control input. Is selected according to the control output with the lower value selected by the row selector 10.

  The opening degree of the discharge valve 3 is determined by the control output of the second pressure regulator 11 using the output of the pressure transmitter 6 as a control input, and the control output of the flow controller 12 using the output of the flow transmitter 7 as a control input. Of these, the value is determined according to the control output with the lower value selected by the low selector 13, but the air release valve 3 operates in reverse to the input control output.

The current regulator 8 outputs a control output obtained by negatively feeding back the deviation of the current value of the main motor 4 from the target value, and serves as a limiter to prevent the main motor 4 from being overloaded. The first pressure controller 9 outputs a control output obtained by negatively feeding back a deviation of the discharge pressure of the turbo compressor 1 from a predetermined target value _PS1 . Under normal operating conditions, the control output of the first pressure regulator 9 is lower than the control output of the current regulator 8, and the control output of the first pressure regulator 9 is input to the inlet guide vane 2 by the low selector 10. The Then, by adjusting the opening degree of the inlet guide vane 2, the discharge pressure of the turbo compressor ₁ is brought close to the target value _PS1 . As a result, the discharge pressure of the turbo compressor ₁ is maintained at the target value _PS1 .

The second pressure controller 11 outputs a control output obtained by negatively feeding back a deviation of the discharge pressure of the turbo compressor ₁ from a target value P _S2 higher than a predetermined target value P _S1 . Since the target value P _S2 of the second pressure regulator 11 is higher than the target value P _S1 , the output of the second pressure regulator 11 rises after the start of the compressor, and maintains 100% if there is no abnormality.

  The flow rate controller 12 outputs a control output obtained by positively feeding back the deviation of the discharge flow rate of the turbo compressor 1 from the target value. The target value of the discharge flow rate of the turbo compressor 1 is a value slightly larger than the surge limit flow rate during steady operation of the compressor, and is a value on the surge control target line that increases or decreases in proportion to the discharge pressure of the turbo compressor 1. Is defined as However, at the start of the compressor, the target value of the discharge flow rate of the turbo compressor 1 is constant to the value indicated by the start control target line translated from the surge control target line to the large flow rate side, that is, the target value during steady operation. Is set to the value obtained by adding the values of.

  Under normal operating conditions with no abnormalities, the control output of the flow rate controller 12 is lower than the control output of the second pressure controller 11 which is 100% output. In that case, the control output of the flow rate controller 12 is input to the discharge valve 3 by the low selector 13. Then, the discharge flow rate of the turbo compressor 1 is brought close to the target value by adjusting the opening degree of the discharge valve 3.

  FIG. 2 shows the startup procedure of the compression apparatus of the present embodiment, and FIG. 3 shows the transition of the pressure and flow rate of the discharge gas at startup. The compressor is started from a state in which the inlet guide vane 2 is fully closed and the air release valve 3 is fully opened.

  First, in step S1, the main motor 4 is started, and in step S2, the system waits for a predetermined standby time to elapse in order to stabilize the rotational speed of the turbo compressor 1. When the rotation speed of the turbo compressor 1 is stabilized, the discharge pressure amount and the discharge flow rate of the turbo compressor 1 become point A in FIG.

  Then, in step S3, the opening adjustment of the inlet guide vane 2 by the current controller 8 or the first pressure controller 9 is started, and in step S4, the activation control target line is applied to the flow controller 12, and in step S5 Then, the opening adjustment of the discharge valve 3 by the second pressure controller 11 or the flow controller 12 is started. As described above, if there is no abnormality in the compressor, the low selector 10 inputs the control output of the first pressure regulator 9 to the inlet guide vane 2, and the low selector 13 controls the control output of the flow regulator 12. Is input to the air discharge valve 3.

  When the inlet guide vane 2 is automatically controlled by the first pressure controller 9 and the air release valve 3 is automatically controlled by the flow rate controller 12, the inlet guide vane 2 is opened and the air is released as shown in FIG. The valve 3 is closed and the discharge flow rate and discharge pressure of the turbo compressor 1 are increased. In this embodiment, since the responsiveness of the flow rate controller 12 is superior to the responsiveness of the first pressure controller 9, the discharge flow rate and the discharge pressure of the turbo compressor 1 in FIG. To rise.

In the case of large air volume than the rated state start target line, the discharge flow rate and discharge pressure of the turbo compressor 1, 3, after reaching to the D ₀ point of the activation control target lines, D ₁ point Move to. On the other hand, when the rated state is smaller than the activation target line, the target value of the discharge flow rate of the turbo compressor 1 is activated after the discharge pressure of the turbo compressor 1 reaches P _s1. is switched from the target line to the surge control target line, the discharge flow rate of the turbo compressor 1 is to follow to move to the surge control target line side, it moves to the _two points D. When the discharge flow rate and the discharge pressure reach the rated values, the discharge valve 3 is fully closed, but the inlet guide vane 2 is not fully opened, leaving a control margin.

  In the compressor of the present embodiment, in step S6, the exhaust valve 3 is fully closed, the discharge pressure of the turbo compressor 1 satisfies the rated value, and the current value of the main motor satisfies the rated value (actually) If any of them reaches, for example, 97% in consideration of the control tolerance, it is assumed that the rated operation state has been entered, and in step S7, the target value of the discharge flow rate of the turbo compressor 1 is set. Switch from the start control target line to the surge control target line. However, if the target value is changed suddenly, the control becomes unstable, so the target value is gradually decreased (the control line is translated) over a predetermined time.

  In step S8, the compressor determines that the pressure increase (startup) has been completed when the discharge flow rate and discharge pressure of the turbo compressor 1 reach the surge control target line. The compressor then performs steady operation.

  Further, in the compressor of the present embodiment, when the determination condition of step S6 is not satisfied, in step S9, the target value of the discharge flow rate of the turbo compressor 1 is determined from the start control target line after waiting for a predetermined time to elapse. Switch to the surge control target line.

  Further, in the present embodiment, when applying the activation control target line, the control parameter (PID coefficient or the like) of the flow rate controller 12 may be changed to a value that emphasizes responsiveness in steady operation. That is, since the margin for the surge limit of the start control target line is large, no surge will occur even if the flow rate overshoots to the low flow rate side, and the flow controller 12 is set to over control, that is, the air release valve 3 can be set to a fast closing speed to shorten the startup time.

  If importance is attached to the stability of steady operation, the flow controller 12 cannot cope with a rapid decrease in demand. Therefore, a flow rate drop detection line is provided, and when the discharge flow rate of the turbo compressor 1 becomes equal to or lower than the flow rate drop detection line (see FIG. 3), the discharge valve 3 is forcibly fully opened to generate a surge. It is good to prevent. Also in this case, it is possible to return to the steady operation by performing the control in which the start control target line is applied to the flow rate controller 12 after Step S3 and Step S4 in FIG.

  Further, the activation control target line may be applied to the flow rate controller 12 also when the compression device of the present embodiment is stopped. In this case, when the inlet guide vane 2 reaches a certain opening, the air release valve 3 maintains (opening) control along the start control target line, and then the air release valve 3 is fully opened, Thereafter, the inlet guide vane 2 is fully closed. Thereby, generation | occurrence | production of the surge in the closing operation | movement of the inlet guide vane 2 can be prevented.

The compression apparatus of embodiment of this invention. The flowchart which shows the starting procedure of the compression apparatus of FIG. The load curve which shows the state change at the time of starting of the compression apparatus of FIG. The time chart which shows the state change at the time of starting of the compression apparatus of FIG. The compression apparatus of conventional embodiment. 6 is a flowchart showing a starting procedure of the compression apparatus of FIG. The load curve which shows the state change at the time of starting of the compression apparatus of FIG. The time chart which shows the state change at the time of starting of the compression apparatus of FIG.

Explanation of symbols

1 Turbo compressor 2 Inlet guide vane (IGV)
3 Air release valve (BOV)
4 Main Motor 5 Current Transmitter 6 Pressure Transmitter 7 Flow Transmitter 8 Flow Controller 9 First Pressure Controller 10 Low Selector 11 Second Pressure Controller 12 Flow Controller 13 Low Selector

Claims (6)

A pressure controller that adjusts the opening of the inlet guide vane so that the discharge pressure of the turbo compressor approaches the target value;
A flow rate controller that adjusts the opening of the discharge valve so that the discharge flow rate of the turbo compressor approaches the target value;
A compression apparatus having a function of simultaneously operating the pressure controller and the flow controller at startup.   The compression apparatus according to claim 1, wherein the target value of the discharge flow rate is set to a larger value as the discharge pressure increases.   The compression apparatus according to claim 2, wherein the target value of the discharge flow rate is set to a larger value at the time of startup than at the time of steady operation.   The compression apparatus according to claim 3, wherein the target value at the start of the discharge flow rate is set to a value obtained by adding a constant value to the target value at the time of steady operation. A pressure controller that adjusts the opening of the inlet guide vane so that the discharge pressure of the turbo compressor approaches the target value;
A method of starting a compressor having a flow rate controller for adjusting an opening degree of an air release valve so that a discharge flow rate of a turbo compressor approaches a target value,
A method of starting a compression device, wherein the pressure controller and the flow controller are operated simultaneously at the time of startup.   6. The method of starting a compression apparatus according to claim 5, wherein at the time of startup, the target value of the discharge flow rate is set to a value larger than that during steady operation.

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