JPH09264500A - Operation control method for gas pipeline boosting facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent surge prevention control from being hindered by calculating a recycling start time, a necessary compressor speed and a recycling flowrate, using a flowrate change signal at a gas pipeline demand end, and then operating and controlling a boosting facility on the basis of the calculated values. SOLUTION: When a control device receives a gas flowrate change signal from a gas demand end, a recycle start time computation process 101 calculates a time t1 required for a compressor station to become capable of coping with a flowrate change. Furthermore, a compressor speed computation process 102 calculates a compressor speed N1 after the reduction of a gas flowrate and a compressor speed computation process 103 after the lapse of the time t1 finds a compressor speed N2 attainable with a compressor over a time from the beginning of speed reduction to the lapse of the time t1. Then, the larger value of N1 and N2 is selected for use as a set value N for a compressor control device and, then, a difference between a flowrate at an operation point corresponding to N and a flowrate after the reduction is used as a recycling flowrate Q1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas pipeline pressure-increasing equipment, and more particularly, to a recycle start time, a compressor rotation speed, and a recycle flow rate even when a rapid gas flow rate change occurs at a gas demand end. The present invention relates to a method of calculating and controlling the operation of booster equipment without impeding surge control.

[0002]

2. Description of the Related Art Consider a case where a rapid flow rate change occurs in a facility (hereinafter referred to as a demand end) which receives a gas supply from a natural gas pipeline. For example, in the case of a plant where the demand end uses natural gas as a fuel, if one of a plurality of gas consuming devices (for example, three gas turbines) in the plant undergoes an emergency stop, the gas flow rate will almost instantly become 2/3 Decrease.

In this case, at the compressor station, the rise in the outlet pressure due to the decrease in the flow rate is detected and the rotational speed of the compressor is lowered. When the flow rate is low and the surge occurs in the compressor, the surge prevention control device opens the station recycle valve or the recycle valve of the compressor to circulate the gas on the inlet side of the compressor to prevent surge while operating. Continue.

Regarding a control method for operating a compressor by using a surge control valve without entering a surge region, a method for controlling a compressor disclosed in Japanese Patent Laid-Open No. 6-58295, "Compressor control device" is disclosed. And there is an example of the device. In this example, the compressor inlet pressure,
It detects the inlet temperature, the suction flow rate, the rotation speed, and the outlet pressure, and adjusts the surge control valve based on the changing speeds thereof.

[0005]

When the compressor station is located near the demand end and the pipeline distance between the two is short, the pipeline does not function as a buffer against the gas flow reduction, and the demand end is reduced. The sharp and drastic decrease of the gas flow rate in the above will directly decrease the flow rate of the compressor of the booster equipment. In such a case, just monitoring the outlet pressure of the compressor station may prevent the control of the compressor drive and the recycle valve from following the rate of flow reduction, and surge prevention control may not function effectively. is there.

An object of the present invention is to provide a method for controlling the operation of booster equipment using a flow rate change signal at the demand end.

[0007]

As means for solving the above problems, the present invention uses a flow rate change signal at the demand end in order to cope with a sudden gas flow rate change at the demand end of the gas pipeline. A method for controlling the operation of a gas pipeline boosting facility is characterized in that the recycling start time, the required number of revolutions of the compressor, and the recycle flow rate are calculated, and the boosting facility is operated and controlled based on the calculated values.

According to the above-mentioned means, the flow rate change signal at the demand end of the gas pipeline is transmitted to the station control device of the boosting equipment, and the rotation speed of the compressor is preliminarily calculated based on this signal, and the compressor after the flow rate is reduced. If the operating point is in the surge area, calculate the recycle flow rate required for surge prevention in advance and control the rotation speed and recycle flow rate before the station outlet pressure detector detects pressure changes. It is the one to start.

[0009]

Embodiments of the present invention will be described.
FIG. 3 shows the configuration of a gas boosting facility including a compressor 4 connected by a pipeline 3 between a gas supply end 1 and a gas demand end 2 and a recycle valve 5 connected in parallel to the compressor 4.

At this time, consider a case where the flow rate sharply decreases at the gas demand end. The operation control process of the present invention at this time is shown in FIG. 1 and described below. 1) A controller (not shown) receives a gas flow rate change signal from the demand end.

2) Recycling start time calculation step 101
Divides the distance from the compressor station to the power plant by the speed of sound in the gas to calculate the time t1 until it is necessary for the compressor station to cope with the flow rate change.

3) Compressor speed calculation step 102
Is the position of the operating point of each compressor after the gas flow rate is reduced, and is predicted on the compressor performance curve shown in FIG.
A compressor rotation speed N1 is calculated when this gas flow rate is evenly distributed by the operating compressors.

4) The compressor rotation speed calculation step 103 after the time t1 is based on the characteristic peculiar to the compressor and the compressor drive machine (the maximum value of the compressor rotation speed lowering speed), The number of revolutions N2 that can be reached after the time t1 is determined.

5) Remove the normal load distribution control logic, and control the compressor drive machine speed and the recycle flow rate as follows.

6) In the case of N1 <N2, it means that the rotation of the compressor cannot be decelerated to the number of rotations corresponding to the reduced flow rate. Therefore, the operating point flow rate corresponding to N2 and the reduced flow rate are Is the recycle flow rate Q1.
The set value of the compressor drive machine controller is set to N2, and the value corresponding to the recycle flow rate Q1 is set to the set value of the recycle valve controller.

7) In the case of N1> N2, the difference between the flow rate at the operating point corresponding to N1 and the reduced flow rate is set as the recycle flow rate Q1. Set the setting value of the compressor drive controller to N
1. The value corresponding to the recycle flow rate Q1 is set as the set value of the recycle valve control device.

8) The maximum value selection process 104 includes N1, N2.
Of these, the larger one is selected and designated as N.

9) The recycle flow rate calculation step 105 calculates the recycle flow rate Q1 corresponding to the rotation speed N shown in FIG.

10) Compressor driver control step 106
Is the compressor drive 1 with the set value of the rotation speed being N.
The rotation speed of 08 is controlled.

11) The recycle valve control step 107 controls the recycle valve 5 with a value corresponding to the recycle flow rate Q1 as a set value.

As a result, the compressor station can respond to the decrease in the flow rate at the demand end without delay, and the trouble of the surge prevention control can be avoided.

Although the present invention shows the station recycle valve as the recycle valve 5 in FIG. 3, it can be applied to the recycle valve provided in each compressor of the compressor station, and the surge provided in each compressor. Similar control can be performed with the control valve.

[0023]

According to the present invention, surge prevention control is not affected by a sudden change in flow rate at the demand end,
The operation of the compressor for boosting pressure can be controlled.

[Brief description of drawings]

FIG. 1 is a diagram showing a step-up facility operation control process of the present invention.

FIG. 2 is a diagram showing a compressor performance curve.

FIG. 3 is a diagram showing an entire gas pipeline system including a gas supply end, a booster, and a demand end.

[Explanation of symbols]

 1 Gas Supply End 2 Gas Demand End 3 Pipeline 4 Compressor 5 Recycle Valve 101 Recycle Start Time Calculation Step 102 Compressor Rotation Speed Calculation Step 103 103 Compressor Rotation Speed Calculation Step after t1 104 Maximum Value Selection Step 105 Recycle Flow Rate Calculation Step 106 Compressor Drive Machine control process 107 Recycle valve control process 108 Compressor drive machine

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Ida 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Ritsuo Sato 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. In order to cope with a sudden change in gas flow rate at the demand end of the gas pipeline, the flow rate change signal at the demand end is used to determine the recycling start time, the required rotational speed of the compressor, and the recycle flow rate. A method for controlling the operation of a gas pipeline booster facility, which comprises calculating and controlling the booster facility according to the calculated value.