AU2006252159A1

AU2006252159A1 - Method for recovering the energy of gas expansion and a recovery device for carrying out said method

Info

Publication number: AU2006252159A1
Application number: AU2006252159A
Authority: AU
Original assignee: TUZOVA ALLA PAVLOVNA
Current assignee: TUZOVA ALLA PAVLOVNA
Priority date: 2000-08-16
Filing date: 2006-12-20
Publication date: 2007-01-18

Description

Our Ref:20144941 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Alla Pavlovna Tuzova 196244, Sankt-Peterburg ul. Tipanova d.29, kv.657 Russian Federation Address for Service: Invention Title: DAVIES COLLISON CAVE Patent Trade Mark Attorneys 255 Elizabeth Street Sydney, New South Wales, Australia, 2000 Method for recovering the energy of gas expansion and a recovery device for carrying out said method The following statement is a full description of this invention, including the best method of performing it known to me:- 5951

IND

SMethod for recovering the energy of gas expansion and a recovery device for carrying out said method FIELD OF THE INVENTION cq The proposed method and the installation are intended for application in systems of reduction of natural gas from high e.g. in the borehole or in main pipelines down to the pressure value required for the tt consumer.

\O BACKGROUND OF THE INVENTION O The known methods of reduction of pressure of gas in boreholes 0io or in main pipelines are based on throttling and using special devices (pressure regulators, valves, cocks etc) for implementation of these methods. [Polytechnic Dictionary, Moscow, "Sovetskaya Entsiklopedia" Publishing House, 1977, pp. 153, 420] These methods and devices for implementation thereof do not utilize: energy of gas expansion and cold generated during this process.

The application of these methods and devices requires sophisticated equipment and consumption of additional power to prevent clogging of pressure regulators by moisture and ice generated during their operation.

A method of utilization of energy of natural gas when its pressure drops from the value in the main pipeline or in the borehole down to the required pressure by conversion of gas expansion energy to mechanical energy is known. [RU 2117173, C 1] This method is implemented in a utilization power installation the inlet of which is connected to the outlet of the high pressure gas borehole or the main pipeline and the outlet to the low pressure gas pipeline or to the gas consumer. This utilization power installation includes a gas expansion machine, e.g. an expansion turbine, and a mechanical energy converter connected cinematically with the gas expansion machine, e.g. an electric generator. Such method

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2 Sand the installation make it possible to utilize gas expansion energy Swhen its pressure drops.

O However this method and the installation do not provide the possibility of utilization of cold generated in the process of gas expansion. The efficiency of this method and the installation is low.

_There is a method of utilization of gas expansion energy when the t gas pressure drops from a high value to the required one by conversion IO of gas expansion energy to mechanical energy with simultaneous O utilization of the gas cooled down during pressure drop as a cooling 0io agent for generation of cold. [SU, Al, 844797] However this method provides a single-stage gas pressure drop and hence total efficiency thereof is reduced.

There is a power installation for utilization of gas expansion energy and the cold generated during this process. [RU 2013616, C 1] Is However efficiency of this installation is low as gas pressure reduction and utilization of cold are effected at a single stage.

DISCLOSURE OF THE INVENTION.

This invention is based on solving the problem of increasing the degree of utilization of cold generated during reduction of gas pressure, generation of greater amount of energy and cold, increase of general effic:iency of the method and the power recovery installation.

The problem set in the proposed method is solved by using the known method of utilization of gas energy during reduction of gas pressure from increased, e.g. in gas pipelines to the required pressure by throttling and/or by conversion of gas expansion energy to mechanical energy with simultaneous application of the gas cooled down in the process of reduction of pressure as a cooling agent in two or several

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3 r subsequent stages and using at least a part of the gas after the first and/or Seach subsequent stage of pressure reduction for obtaining and application of cold.

Due to stage-by-stage reduction of gas pressure and application of the whole amount of gas or a part thereof as a cooling agent after the first and/or each subsequent stage of reduction of gas pressure general efficiency of the method is increased.

I, The said problem is solved by using a power recovery installation the inlet of which is connected to a borehole or a high pressure gas pipeline and the outlet of which to the low pressure gas pipeline, that contains an expander, e.g. an expansion turbine and a converter of mechanical energy, e.g. an electric generator cinematically connected to the expander. The said installation comprises at least one heat exchanger the outlet branch pipe of which is connected to the outlet of the expander, e.g. to the outlet of the expansion turbine.

A new feature of the proposed power recovery installation is that the expander, e.g. the expansion turbine consists of two or several parts arranged in the direction of pressure reduction; the installation also comprises two or several heat exchangers- refrigerators the inlet branch pipe of the cooling agent of each heat exchanger- refrigerator being connected to the outlet of the relevant part of the expander and the number of heat exchangers- refrigerators being not less than the number of parts of the expander.

Such improvement of the power recovery installation makes it possible to increase the efficiency of the installation and the amount of generated cold.

In the power recovery installation the outlet of the preceding part of the expander can be connected simultaneously both to the inlet of the

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4 subsequent part of the expander and to the inlet of the relevant heat exchanger- refrigerator and the outlet of the same heat exchangerrefrigerator to the low pressure gas pipeline or to the gas consumer. In this case the flow of the working medium is taken off for utilization of cold. It improves thermodynamical working cycle of the installation.

Such improvement increases the efficiency of the installation. At ~the sa.me time it becomes possible to ensure optimal regulation of the INO expander when the operational mode changes.

In the power recovery installation the outlet of the preceding part i0 of the expander can be connected only to the inlet branch pipe of one or each heat exchanger- refrigerator located between two parts of the expander and the outlet branch pipe of the same heat exchangerrefrigerator located between two parts of the expander can be connected to the inlet of the working medium of the subsequent part of the expander. In this case the working medium (the gas) in one or in each heat exchanger- refrigerator is heated additionally which improves the thermodynamical cycle of the installation.

Such improvement increases additionally the efficiency of the installation due to utilization of the cold of the cooling agent heated by heat exchange in the heat exchanger refrigerator. At the same time it becomes possible to ensure optimal regulation of the operation of the expander when the operational mode changed by changing the amount and/or temperature of gaseous or liquid working medium or several working media heated in heat exchangers- refrigerators.

BRIEF DESCRIPTION OF DRAWINGS.

In FIG. 1 the diagram of a utilization power installation is shown.

The installation includes an expansion gas turbine that contains a high

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pressure component and a low pressure component, two heat a exchangers-refrigerators and an electric generator.

In FIG. 2 the diagram of a utilization power installation is shown.

The installation includes an expansion gas turbine that contains a high pressure component, a medium pressure component and a low pressure component, three heat exchangers-refrigerators and an electric tt- generator.

IDIn FIG. 3 the diagram of a utilization power installation is shown.

0, The installation includes expansion gas turbines that contain high pressure components, medium pressure components and low pressure components, three heat exchangers-refrigerators and three electric generators.

The invented method and the installation are illustrated by descriptions of the preferred embodiments thereof the embodiments of implementation of the utilization of gas expansion energy being described in the disclosure of operation of variants of the installation.

Variant 1. (FIG. 1) The power recovery installation contains an expansion gas turbine, which is composed of axially located high pressure part 1 (HPP 1) and low pressure part 2 (LPP The inlet of HPP 1 is connected to high pressure gas pipeline 3. This pipeline 3 can be a high or medium pressure natural gas pipeline, a pipeline of a gas distribution station, a thermal power station, a boiler house, a borehole at the place of natural gas production etc (these facilities are not shown in the drawings). HPP 1 and LPP 2 mounted on the same shaft are connected cinematically or directly to electric generator shaft 4 that supplies electric power to consumer 5. The outlet of HPP 1 is connected both to the inlet of LPP 2 and to the inlet of heat exchanger-refrigerator 6. The outlet branch pipe

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6 of the cooling agent of heat exchanger-refrigerator 6 is connected to low Spressure gas pipeline through which the gas is supplied to consumer 7.

At the outlet of the gas out of LPP 2 of the expansion gas turbine heat exchanger-refrigerator 6 is mounted, the inlet branch pipe of the cooling agent of which is connected to the outlet of the gas out of LPP 2 of the expansion gas turbine, and the outlet branch pipe of heat (,i t exchanger-refrigerator 6 to the low pressure gas pipeline through IND which the gas is supplied to consumer 7.

The power recovery installation operates in the following way.

0to The gas is fed from high pressure pipeline 3 into HPP 1, rotates the same, expanding and cooling down. A part of this gas flows into LPP 2 and another part to the inlet of heat exchanger-refrigerator 6. Partially cooled and under partially reduced pressure the gas flows through heat exchanger -refrigerator 6. Next the gas under required pressure is delivered to consumer 7.

Another part of the gas fed into LPP 2 of the expansion gas turbine performs additional work, decreases pressure and is cooled down. This gas flows out of LPP 2 into second heat exchangerrefrigerator 8, where the gas is heated and cold is taken off the gas. Then the gas under low pressure is delivered to consumer 9. The expansion gas turbine, that includes HPP 1 and LPP 2, rotates electric generator 4.

Electric power is supplied to power consumer Cold can be used for freezing chambers, ice rinks etc and for liquefying natural gas produced from boreholes. The useful work performed by the gas in the process of expansion can be also used for gas liquefying and power supply of a separate natural gas borehole.

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7 Variant 2. (FIG.2) SThe power recovery installation includes an expansion gas O turbine, that comprises high pressure part 10 (HPP 10), medium pressure part 11 (MPP 11) and low pressure part 12 (LPP 12) mounted on the same axle. The inlet of HPP 10 is connected to high pressure gas pipeline 13. The outlet of HPP 10 is connected both to the inlet of MPP t 1, and to the inlet of heat exchanger-refrigerator 16. The outlet of the gas O out of heat exchanger-refrigerator 16 is connected to consumer 17 of ,i low pressure gas. The outlet of MPP 11 is connected both to the inlet of io LPP 12, and to the inlet of heat exchanger-refrigerator 18. The outlet of the gas out of heat exchanger-refrigerator 18 is connected to consumer 19 of low pressure gas. The outlet of LPP 12 is connected to the inlet of heat exchanger-refrigerator 20. The outlet of the gas out of heat exchanger-refrigerator 20 is connected to consumer 21 of low pressure gas.

The power recovery installation operates in the following way.

The gas is fed from high pressure gas pipeline 13 into HPP 10, rotating the same, expanding and cooling down. A part of this gas flows into MPP 11, rotating the latter, expanding and cooling down, the other part is fed to the inlet of heat exchanger-refrigerator 16, and from there to consumer 17 of low pressure gas. Pressure, required by gas customer 17, can be higher than the pressure required by other gas consumers 19 and 21. Another part of the flow performs work in MPP 11, reduces pressure additionally and is cooled down. Next the gas flow is branched. One part of this flow is fed to the inlet of heat exchanger-refrigerator 18, from which the gas flows to consumer 19. The rest of the flow is delivered to the inlet of LPP 12, rotating the latter, expanding and cooling down.

Next the gas is fed into heat exchanger refrigerator 20, and from there-

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8 Sto consumer 21 of low pressure gas. The expansion gas turbine rotates electric generator 14, that generates electric power for consumer Cold can be used for freezing chambers, ice rinks etc and for liquefying natural gas produced from boreholes. The useful work performed by the gas in the process of expansion can be also used for gas liquefying and power supply of a separate natural gas borehole.

t Variant 3. (FIG.3) IND The power recovery installation includes high pressure expansion Sgas turbine 22 (HPT 22), the inlet of which is connected to high pressure gas pipeline 23. The shaft of HPT 22 is connected cinematically or directly to electric generator 24, which is connected electrically to electric power consumer 25. The outlet of HPT 22 is connected to the inlet of heat exchanger-refrigerator 26. The outlet of heat exchangerrefrigerator 26 is connected to the inlet of medium pressure expansion gas turbine 27 (MPT 27). The shaft of MPT 27 is connected cinematically or directly to electric generator 28, which is connected electrically to electric power consumer 29. The outlet of MPT 27 is connected to the inlet of heat exchanger-refrigerator 30. The outlet of heat exchanger-refrigerator 30 is connected to the inlet of low pressure gas expansion turbine 31 (LPT 31). The shaft of LPT 31 is connected cinematically or directly to electric generator 32, which is connected electrically to electric power consumer 33. The outlet of LPT 31 is connected to the inlet of heat exchanger-refrigerator 34. The outlet of heat exchanger-refrigerator 34 is connected to consumer 35 of low pressure gas.

The power recovery installation operates in the following way.

The gas is fed from high pressure pipeline 23, into HPT 22, rotating the latter, expanding and cooling down. The gas is fed from HPT 22 into heat exchanger-refrigerator 26, in which cold is utilized and the gas is heated and expanded. Next the gas is delivered to MPT 27, rotating the same, expanding and cooling down. Then the gas flows into heat exchanger -refrigerator 30, in which cold is utilized and the gas is heated and expanded. The heated and expanded gas is fed from heat exchangerrefrigerator 30 into LPT 31, rotating the latter, expanding and cooling down. The gas flows from LPT 31 into heat exchanger -refrigerator 34, in which cold is utilized and the gas is heated and expanded. Next the gas is delivered to consumer 35 of low pressure gas. HPT 22, MPT 27 l0 and LPT 31 rotate electric generators 24, 28 and 32 respectively, which supply electric power to consumers 25, 29, 33 respectively. Electric generators 24, 28 and 32 can be connected to a common electric network.

Due to stage-by-stage cooling of the gas in HPT 22, MPT 27 and LPT 31 and stage-by-stage heating in heat exchangers-refrigerators 26 and general efficiency of the power recovery installation is increased.

Due to stage-by-stage cooling down of gas in HPT 22, MPT 27 and LPT 31 and stage-by-stage heating of the same in heat exchangersrefrigerators 26 and 30 total efficiency of utilization power installation increases.

INDUSTRIAL APPLICABILITY.

The invention can be used for solving a wide scope of practical problems of generation of additional energy and non-expensive cold.

The invention can be used at the outlet of high pressure natural gas directly out of boreholes and for reduction of gas pressure at the outlet of main pipelines down to the pressure required by the consumer etc.

In all descriptions of preferred embodiments an expansion gas turbine is used as a gas expansion machine. However a gas expansion IND O C1 machine of any type can be used, e.g. piston or rotor type gas aU expansion machines, including those comprising high pressure and low Spressure components or high pressure, medium pressure and low pressure components.

Turbines, pumps, ventilators, winches or other converters of t_ mechanical energy can be used instead and/or simultaneously with the ~electric generator.

IND Utilization power installations described in preferred 0 embodiments of the invention utilization power installations can be located directly beside natural gas boreholes if natural gas pressure at the outlet of the borehole exceeds pressure required for the gas main pipeline. In this case cold can be used for liquefaction of natural gas produced. The useful work performed by gas in the process of expansion can be used for liquefaction of gas power supply of a remote natural gas borehole. The utilization power installations proposed are very efficient in places where gas main pipelines are connected to installations for natural gas supply to big consumers (electric power plants, domestic natural gas networks in settlements etc).

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Claims

1. A method of utilization of the natural gas expansion energy during the process of reduction of gas pressure from high gas pressure to a lower gas pressure by conversion of natural gas expansion energy to mechanical energy with the aid of the gas cooled down in the process of pressure reduction as a cooling agent for generation of cold, wherein natural t gas pressure is reduced in two or more successive stages simultaneously with conversion IDof natural gas expansion energy to mechanical energy at each stage, and wherein the total amount of natural gas or a part of natural gas being used as a cooling agent for generation (,i of cold after the first and/or relevant successive stage of natural gas pressure drop.

2. A method according to claim 1, wherein a part of natural gas after the first and/or relevant successive stage of natural gas pressure drop or the total amount of natural gas used as a cooling agent is used for the subsequent stage of conversion of natural gas expansion energy to mechanical energy.

3. A gas power installation including a gas expansion machine with an inlet, the inlet of which is connected to high pressure natural gas borehole or main pipeline, and a mechanical energy conversion device cinematically connected to the gas expansion machine, wherein the mechanical energy conversion device includes at least one electric generator and at least one heat-exchanger, the inlet branch pipe of which from the cooling agent side is connected to the outlet of the gas expansion machine and the outlet of each said heat exchanger is connected to the lower pressure gas main pipeline, and wherein the gas expansion machine have two or more components, arranged successively in the direction of the reduction gas pressure the number of heat exchangers being not less than the number of components of the gas expansion machine, and the inlet branch pipe from the cooling agent side of the relevant heat exchanger is connected to the outlet of the gas expansion machine component of the gas expansion machine.

4. A gas power installation according to claim 3, wherein the outlet of preceding component of the gas expansion machine is connected both to the inlet of next component of the gas expansion machine and to the inlet branch pipe from the cooling agent side of P.\WPDo CS\Xs\LN\206\scci\TO O ALLA PAVLOVNANI SCpI_776488D0cLdiws dc.2011210006 12, CD relevant heat exchanger, and wherein the outlet branch pipe from the cooling agent side of one or more heat exchanger is connected to respective said low pressure natural gas O C1 pipeline. t 5

5. A gas power installation according to claim 3, wherein the outlet of preceding CN component of the gas expansion machine is connected only to the inlet branch pipe from CN the cooling agent side of heat exchanger, and wherein the outlet branch pipe from the O cooling agent side of one or more heat exchangers is connected to the inlet of the working C, medium of next component of the gas expansion machine.

6. A method of utilization of the natural gas expansion energy in accordance with either claim 1 or claim 2 and substantially as herein described with reference to any one of the accompanying figures.

7. A gas power installation in accordance with any one of claims 3 to 5 substantially as herein described with reference to any one of the accompanying drawings.