RU2620624C1 - Expander-generator set - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in the composition of the gas distribution stations (GDS) and gas control points (GCP) for gas flow energy utilisation. An expander-generator set with a control system, including an electric generator, a drive-operated regulating device, a signal amplifier and a comparison unit, characterized in that a volumetric air motor is additionally installed in the reduction line between the safety shut-off valve and the pressure regulator. The output of the volumetric air motor is connected to its input via a control valve, the pressure difference sensor on the volumetric air motor is connected to the comparison element, the signal amplifier and the actuator connected to the control valve.

EFFECT: possibility of an expander-generator set operation with relatively low pressures and costs, regardless of the unevenness of gas withdrawal by consumers and changes in the moment of resistance, as well as an increase in the utilized energy.

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Description

The invention relates to the field of gas supply and can be used as part of gas distribution stations (GDS) and gas control points (HF) to utilize the energy of the gas stream.

A known installation for utilizing the energy of expansion of natural gas (RF patent No. 2206838, publ. 06/20/2003). The invention provides the generation of large amounts of energy and cold by connecting to a well or main gas pipeline a waste power plant containing an expander with a kinematically coupled electric generator and two or more heat exchangers.

The disadvantage is the need for its effective operation of high inlet pressure and gas flow, which limits the range of objects for its application.

There is a method of sustainable gas supply to a gas distribution station with an energy-refrigerating complex that uses natural gas overpressure energy and a system to implement the method for generating electric energy and cold (RF patent No. 2346205, published on 02/10/2009). The group of inventions simultaneously generates electric energy and cold using an energy refrigeration unit connected in parallel with the GDS, containing expander-generator units with heat exchangers and an automatic synchronization system for opening / closing reduction lines with stopping / turning on the expander-generator units.

The disadvantage is a variable gas supply to consumers, in addition, for stable operation, high pressure and gas flow are necessary.

Known pneumatic expander-generator unit (RF patent No. 2525027, publ. 08/10/2014), capable of operating at low inlet pressure and volumetric gas flow by using a gear air motor as an expansion machine.

The disadvantage is the lack of a regulatory system that is necessary to operate with variable gas flow rates due to uneven gas sampling by consumers.

A device for regulating a turboexpander (RF patent No. 2579301, publ. 04/10/2016), adopted as a prototype installed in parallel with a gas distribution station and containing a turboexpander, generator, stop valve, two regulating bodies with actuators, a bypass valve, an operating mode switch, an adder , three elements of comparison, pressure and load sensors of an external electric network, a frequency converter, a filter and a rectifier. This device allows you to adjust the operation of the turbo-expander depending on the load of the external electrical network, to reduce fluctuations in gas pressure in the low-pressure line, and also to increase the reliability of the turbo-expander.

The disadvantages of this device are the possibility of efficient operation of the expander-generator set as a whole only at stable relatively high pressures and gas flows, as well as the excessive complexity of the system with high losses of gas flow energy.

The technical result is the ability to operate the expander-generator set with relatively low pressures and costs, regardless of the uneven selection of gas by consumers and changes in the moment of resistance, as well as an increase in the share of utilized energy.

The technical result is achieved by the fact that on the reduction line between the safety shut-off valve and the pressure regulator, a volume air motor is additionally installed, while the output of the volume air motor is connected to its input via a control valve, the differential pressure sensor on the volume air motor is connected to the comparison element, signal amplifier and actuator associated with the control valve.

The device is illustrated by the following figure:

FIG. 1 is a schematic diagram of an expander-generator unit with a control system for it as an example of a reduction line of a gas control station, where:

1 - expander-generator unit with a system for its regulation;

2 - gas pressure reduction line;

3 - shut-off valve;

4 - filter;

5 - safety shutoff valve;

6 - gas pressure regulator;

7 - safety relief valve;

8 - volume air motor;

9 - electric generator;

10 - control valve;

11 - differential pressure sensor on a volumetric air motor;

12 - element of comparison;

13 - signal amplifier;

14 - actuator.

An expander-generator unit with its control system 1 (Fig. 1) located on the reduction line 2 between the safety shut-off valve 5 and the gas pressure regulator 6 includes: a volume air motor 8 located directly on the reduction line 2 and kinematically connected with the electric generator 9, the output of the air motor 8 is connected to its input through a control valve 10, which is driven by an actuator 14 through a signal amplifier 13, a comparison element 12 and a differential pressure sensor on the volumetric nevmodvigatele 11.

On the reduction line 2 are sequentially located: shut-off valve 3, filter 4, safety shut-off valve 5, expander-generator unit with its control system 1, pressure regulator 6, shut-off valve 3, safety relief valve 7.

The device operates as follows. During gas sampling by consumers, gas passes through a shut-off valve 3, a filter 4 and a safety shut-off valve 5, a volume air motor 8, a control valve 10, a gas pressure regulator 6, a shut-off valve 3.

After the safety shut-off valve 5, the flow is divided depending on the degree of opening of the control valve 10. The part passes through a volumetric air motor 8, where, losing energy, it performs work that is converted into mechanical, and then, using an electric generator 9, into electrical energy. The other part passes through a parallel line that connects the output of the volumetric air motor 8 with its input and contains a control valve 10.

The angular velocity of the rotor of the electric generator depends on the moment on its shaft, which is determined by the electric load and the pressure drop across the volume air motor. The pressure difference corresponding to the nominal angular velocity is determined by calculation and is the set point for the control system.

To regulate the volumetric air motor 8, the sensor 11 generates a signal proportional to the pressure differential, which is compared on the comparison element 12 with the setpoint signal, after which a control signal is generated, which is transmitted through the signal amplifier 13 to the actuator 14 connected to the control valve 10.

With a decrease in gas sampling by consumers, the pressure after the volumetric air motor increases, and the differential on it decreases accordingly below the setpoint, which is revealed by the comparison element 12. To maintain it using the signal amplifier 13 and actuator 14, the control valve 10 closes, thereby increasing the gas flow, passing through the volumetric air motor until the pressure differential across the air motor is equal to the setpoint.

With an increase in gas sampling by consumers, the device operates in the reverse order.

Claims (1)

An expander-generator unit with its regulation system, including an electric generator, a regulating body with a drive, a signal amplifier and a comparison unit, characterized in that an additional air motor is additionally installed on the reduction line between the safety shut-off valve and the pressure regulator, while the output of the air motor is connected to it the entrance through the control valve, the differential pressure sensor on the volumetric air motor is connected to the comparison element, the signal amplifier and actuator Twomey, associated with the control valve.

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