SU808702A1 - System for protection of compressor unit - Google Patents

Description

one

The invention relates to the control of compressor plants and installations, in particular, natural gas superchargers of gas pumping units of compressor stations of main gas pipelines.

A known anti-surge protection system for a compressor unit, comprising gas flow sensors through a compressor and pressure differential across a compressor with a protective grid, is connected via an adder to smooth and relay gas bypass controllers, the outputs of which are connected to the gas bypass actuators as well as the automatic gas flow control unit controlling the frequency of rotation of the compressor drive associated with the executive mechanism for supplying fuel to the combustion chamber and the emergency stop valve va llj drive.

A disadvantage of the known system is that it does not take into account the characteristic technical features of the compressor units, namely:

for a compressor unit driven by a gas turbine engine, the operating mode may vary

Both automatically and by operator changing the rotation frequency of the compressor rotor. In this case, a deep decrease in the rotation frequency may lead to unstable operation of the compressor. The known system does not provide for limiting the frequency of the turnaround from the point of view of the occurrence of surge compressor oscillations;

A number of compressor installations, for safety reasons with regard to the impeller blades of the compressor, provide for the installation of a protective grid at the compressor inlet. The screen periodically becomes clogged, and this is associated with loss of stable operation by the compressor. A known system in this case protects the compressor from surging.

The purpose of the invention is to increase the reliability of the protection of the compressor against. surging.

The goal is achieved

5 in that the system contains a differential pressure sensor on the protective grid, a compressor rotor speed sensor, a calculator and a memory device associated with the rotation frequency and differential pressure sensors on the compressor, the calculator inputs connected to flow and rotation frequency sensors, the logic device inputs associated with the outputs of the differential pressure sensor on the protective grid, the calculator and the storage device, and the outputs of the logic device to the inputs of the automatic frequency control unit drive of the compressor and crane of emergency stop.

The drawing shows a block diagram of the system.

The system contains sensors 1 and 2 of gas flow through the compressor and pressure drop across the compressor, adder 3, gas flow controllers 4 and 5, a logical device b, actuator 7 and 8 gas bypass, a drive rotation frequency control unit 9 10 of the compressor, the actuator 11 for supplying fuel to the combustion chamber 12, the valve 13 for the emergency stop of the drive, the differential pressure sensor 14 on the protective grid, the sensor 15 for the rotational speed of the compressor rotor, the calculator

16 and a storage device 17. The drawing shows the compressor

18 (supercharger) with safety net

19 at the inlet and with a gas turbine actuator 10 consisting of an air compressor 20, a gas turbine 21, and a power turbine 22.

The system works as follows.

After the system has entered the mode, the device 17 stores the values of the output signals of the sensors 2 and 15. When the operation mode of the compressor 18 changes, the memory device

17 sends to the logical device a signal about the reason for changing the mode.

When the compressor's operating mode changes, due to a change in load caused, for example, by a decrease in gas consumption by the consumer, the signals from sensors 1 and 2 are compared in adder 3, after which the error signals go to the inputs of regulators 4 and 5. When there is a signal from the memory control device 17 The tori 4 and 5 use the logic device 6 to control the actuators 7 and 8. Opening the actuators 7 and 8 allows the gas to be bypassed from the output to the input of the compressor. It contributes to the establishment of the steady state of operation. In this case, if the loading (disturbance) changes slowly, the signal of the adder 3 switches on the smooth gas bypass circuit consisting of the regulator 4 and the actuator 7, With discontinuous load disturbances by the signal of the adder 3 the relay bypass circuit turns on gas consisting of a regulator 5 and an executive mechanism 8.

When the mode of operation of the compressor caused by a deep decrease in the rotation frequency changes, the calculator 16, according to the sensor signals 1 and 15 and in the presence of a signal from the storage device 17, introduces, via a logic device b, a correction signal to the rotation frequency control unit 9 controlling the actuator 11. The actuator 11 changes the dosage of the amount of fuel supplied to the combustion chamber 12 of the drive 10, the compressor 18, and thereby limits the further reduction of the rotation frequency of the compressor rotor.

When the protective grid 19 becomes clogged, when the retention of the compressor in the stable operating area by either gas bypass or speed variation is inefficient, the signal of the differential pressure sensor 14 on the protective grid 19 enters the logic device b, blocking the control channels of the actuators 7, 8 and 11 and controls a valve 13 stopping the supply of fuel to the combustion chamber 12. There is an emergency stop installation.

Thus, the completeness of the use in the proposed system of information about the state of the compressor unit, the ability to recognize the reasons for its mode of operation and the formation of the most appropriate installation control command allows increasing the reliability of the compressor protection against surge.

Claims (1)

1. USSR author's certificate No. 408056, cl. F O D 27/02, 1975.