EP0105593A1 - Dispersing liquid slugs in gas pipelines - Google Patents

Dispersing liquid slugs in gas pipelines Download PDF

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Publication number
EP0105593A1
EP0105593A1 EP83304911A EP83304911A EP0105593A1 EP 0105593 A1 EP0105593 A1 EP 0105593A1 EP 83304911 A EP83304911 A EP 83304911A EP 83304911 A EP83304911 A EP 83304911A EP 0105593 A1 EP0105593 A1 EP 0105593A1
Authority
EP
European Patent Office
Prior art keywords
gas
pipeline
emitting device
liquid
slugs
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83304911A
Other languages
German (de)
French (fr)
Inventor
Murray K. Nicholson
John R. Nickerson
Khalid Aziz
Garry A. Gregory
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atomic Energy of Canada Ltd AECL
Original Assignee
Atomic Energy of Canada Ltd AECL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atomic Energy of Canada Ltd AECL filed Critical Atomic Energy of Canada Ltd AECL
Publication of EP0105593A1 publication Critical patent/EP0105593A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
    • F17D3/00—Arrangements for supervising or controlling working operations
    • F17D3/12—Arrangements for supervising or controlling working operations for injecting a composition into the line
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
    • B01F23/232—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
    • F17D3/00—Arrangements for supervising or controlling working operations
    • F17D3/14—Arrangements for supervising or controlling working operations for eliminating water

Definitions

  • This invention relates to dispersing liquid slugs in gas pipelines in order to reduce the destructive effect on components in the pipeline.
  • condensed gas and water form a liquid fraction which can, under certain conditions, form slugs that are carried along by the gas at the velocity of the gas.
  • the impact of such slugs can damage components in the pipeline, such as separators or valves as found at a compressor station.
  • the present invention provides an apparatus for dispersing liquid slugs in a gas pipeline comprising a gas emitting device communicating with said pipeline, said device having a plurality of outlets for emitting gas, and means for connecting said chamber with a source of gas.
  • the invention further provides a method of dispersing liquid slugs in a gas pipeline comprising introducing a gas into the liquid to form a gas-liquid mixture.
  • a typical compressor station for a gas pipeline 1 includes a turbo-compressor 2, a separator 3 and a valve 4.
  • a gas emitting device 5 is positioned upstream of the components to be protected, namely the valve 4 and separator 3. As shown, gas is supplied to the gas emitting device 5 from the turbo-compressor outlet by means of a suitable conduit 6.
  • Figure 2 shows the gas emitting device 5 and the effect on liquid slugs in the pipeline 1.
  • One slug 10 is shown approaching the gas emitting device 5 while another slug is being dispersed in region 11.
  • the gas emitting device 5 comprises a porous chamber defining a plurality of outlets 7. Each outlet or pore 7 provides a nucleation site for a bubble in the liquid. The emitted bubbles break up the incompressible liquid slug to form a compressible gas-liquid mixture.
  • the bubbles After formation, the bubbles begin to coalesce into large bubbles and flow will subsequently revert to separated gas and liquid, and again be suseptible to slugging.
  • the pores In order to prolong the duration of compressible gas-liquid mixture mode of flow, the pores should be as small and numerous as practical.
  • the outlet diameter should be less than 1% of the pipeline diameter.
  • the distance the gas emitting device can be placed upstream of the components to be protected is limited. It appears that protection against slugging can be provided for a distance up to 60 pipeline diameters, but preferably the emitting device should be placed within 30 diameters of the component or components to be protected.
  • the gas emitting device and outlets may take various forms.
  • the emitting device may be formed of woven stainless steel wire mesh or grid, or sintered stainless steel. With such construction, the outlet or pore size can be made less than 50 pm.
  • Figure 3 shows an alternate embodiment for the gas emitting device, in the form of a sparger.tube 15 provided with outlets 17 and supplied with gas through inlet 16.
  • FIGS 4 and 5 illustrate another embodiment of the gas emitting device.
  • Gas is introduced into the pipeline 20 through outlets 27 of a perforated section 25 of the pipeline.
  • the perforated section 25 is enclosed by manifold 28 to which gas is supplied through inlet 26.
  • gas may be supplied to the emitting device 5 on a continuous basis, for example, when the incidence of slugging is high, or only when a slug is approaching.
  • a slug detector 12 is provided a suitable distance upstream.
  • the detector 12 may take various forms such as a conductance probe, acoustic sensor or radio-frequency densitometer.
  • the gas emitting device should have a length of at least five pipeline diameters.

Abstract

Liquid slugs in gas pipelines (1) are dispersed by injecting gas into the liquid, producing a compressible gas-liquid mixture. Placed upstream of a compressor station (2), the present invention can be used to protect valves (4) and separators (3) from the destructive effect of liquid slugs.

Description

  • This invention relates to dispersing liquid slugs in gas pipelines in order to reduce the destructive effect on components in the pipeline.
  • In gas pipelines, condensed gas and water form a liquid fraction which can, under certain conditions, form slugs that are carried along by the gas at the velocity of the gas. The impact of such slugs can damage components in the pipeline, such as separators or valves as found at a compressor station.
  • It is an object of the present invention to enable liquid slugs to be dispersed and thereby reduce the destructive effect thereof.
  • The present invention provides an apparatus for dispersing liquid slugs in a gas pipeline comprising a gas emitting device communicating with said pipeline, said device having a plurality of outlets for emitting gas, and means for connecting said chamber with a source of gas.
  • The invention further provides a method of dispersing liquid slugs in a gas pipeline comprising introducing a gas into the liquid to form a gas-liquid mixture.
  • It has been found that, by injecting gas into a gas pipeline upstream of a component or components to be protected, liquid slugs in the pipeline can be dispersed. The gas introduction generates bubbles and breaks up the slugged flow to form a compressible gas-liquid mixture, substantially reducing the potential for damaging components in the pipeline.
  • By way of example, embodiments of the invention will be described with reference to the accompanying drawings, in which:
    • Figure 1 is a schematic diagram illustrating a compressor station incorporating the present invention.
    • Figure 2 is an enlarged cross-sectional view showing details of one form of gas emitting device mounted in a gas pipeline.
    • Figure 3 is a cross-sectional view of another form of gas emitting device mounted in a gas pipeline.
    • Figure 4 is a partly sectional view of another form of the gas emitting device associated with a gas pipeline.
    • Figure 5 is a sectional view taken at 5-5 of Figure 4.
  • Referring to Figure 1, a typical compressor station for a gas pipeline 1 includes a turbo-compressor 2, a separator 3 and a valve 4. A gas emitting device 5 is positioned upstream of the components to be protected, namely the valve 4 and separator 3. As shown, gas is supplied to the gas emitting device 5 from the turbo-compressor outlet by means of a suitable conduit 6.
  • Figure 2 shows the gas emitting device 5 and the effect on liquid slugs in the pipeline 1. One slug 10 is shown approaching the gas emitting device 5 while another slug is being dispersed in region 11. The gas emitting device 5 comprises a porous chamber defining a plurality of outlets 7. Each outlet or pore 7 provides a nucleation site for a bubble in the liquid. The emitted bubbles break up the incompressible liquid slug to form a compressible gas-liquid mixture.
  • After formation, the bubbles begin to coalesce into large bubbles and flow will subsequently revert to separated gas and liquid, and again be suseptible to slugging. In order to prolong the duration of compressible gas-liquid mixture mode of flow, the pores should be as small and numerous as practical. The outlet diameter should be less than 1% of the pipeline diameter.
  • Since flow will eventually revert to the slugging mode, the distance the gas emitting device can be placed upstream of the components to be protected is limited. It appears that protection against slugging can be provided for a distance up to 60 pipeline diameters, but preferably the emitting device should be placed within 30 diameters of the component or components to be protected.
  • The gas emitting device and outlets may take various forms. In the embodiment of figure 2, the emitting device may be formed of woven stainless steel wire mesh or grid, or sintered stainless steel. With such construction, the outlet or pore size can be made less than 50 pm.
  • Figure 3 shows an alternate embodiment for the gas emitting device, in the form of a sparger.tube 15 provided with outlets 17 and supplied with gas through inlet 16.
  • Figures 4 and 5 illustrate another embodiment of the gas emitting device. Gas is introduced into the pipeline 20 through outlets 27 of a perforated section 25 of the pipeline. The perforated section 25 is enclosed by manifold 28 to which gas is supplied through inlet 26.
  • With reference to figure 1, gas may be supplied to the emitting device 5 on a continuous basis, for example, when the incidence of slugging is high, or only when a slug is approaching. For the latter, a slug detector 12 is provided a suitable distance upstream. An actuator 14, in response to a signal from the detector 12, opens the normally closed valve 13 when a slug is detected. The detector 12 may take various forms such as a conductance probe, acoustic sensor or radio-frequency densitometer.
  • Although even small amounts of gas introduced by the gas emitting device provides some attenuation of the distructive effects of slugs, it appears that at least 5X of the gas flow rate is required to provide a significant degree of protection. On the other hand, it appears impractical to exceed 25X of the gas flow rate, since little additional protection against slugs is provided, and because additional gas introduced increases pressure losses that reduce the overall efficiency of the compressor station. The optimum amount of gas introduction appears to be in the range of 15 to 25X of the gas flow rate. The actual amount of gas introduced in a particular application will depend on various factors such as the degree of protection desired, or whether the system will operate in a continuous mode, or on an intermittent basis with a slug detector as described above.
  • In order to be able to introduce a sufficient amount of gas into the pipeline, it appears that the gas emitting device should have a length of at least five pipeline diameters.

Claims (12)

1. An apparatus for dispersing liquid slugs in a gas pipeline comprising a gas emitting device communicating with said pipeline, said device having a plurality of outlets for emitting gas, and means for connecting said chamber with a source of gas.
2. The apparatus of claim 1 wherein the outlets'of the gas emitting device have diameters less than 1% of the pipeline diameter.
3. The apparatus of claim 1 wherein the outlets have a diameter less than 50 µm.
4. The apparatus of claim 1 wherein said gas emitting device comprises a porous chamber defining the outlets for the gas.
5. The apparatus of claim 1 wherein said gas emitting device is disposed within 60 pipeline diameters of a component to be protected.
6. The apparatus of claim 1 wherein said gas emitting device is disposed within 30 pipeline diameters of a component to be protected.
7. The apparatus of claim 1 wherein the length of the gas emitting device is not less than 5 times the diameter of the pipeline.
8. A method of dispersing liquid slugs in a gas pipeline comprising introducing a gas into the liquid to form a gas-liquid mixture.
9. The method of claim 8 wherein the gas is introduced within 60 pipeline diameters of a component to be protected.
10. The method of claim 8 wherein the gas is introduced within 30 pipeline diameters of a component to be protected.
11. The method of claim 8 wherein gas is introduced at a rate of from 5 to 25X of the gas flow rate in the pipeline.
12. The method of claim 8 wherein gas is introduced at a rate of from 15 to 25X of the gas flow rate in the pipeline.
EP83304911A 1982-09-03 1983-08-25 Dispersing liquid slugs in gas pipelines Withdrawn EP0105593A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA410730 1982-09-03
CA410730 1982-09-03

Publications (1)

Publication Number Publication Date
EP0105593A1 true EP0105593A1 (en) 1984-04-18

Family

ID=4123525

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83304911A Withdrawn EP0105593A1 (en) 1982-09-03 1983-08-25 Dispersing liquid slugs in gas pipelines

Country Status (2)

Country Link
EP (1) EP0105593A1 (en)
NO (1) NO833013L (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0464797A1 (en) * 1990-07-05 1992-01-08 Linde Aktiengesellschaft Methode and device for introducing gas in a fluid
US8047292B2 (en) * 2004-12-06 2011-11-01 Baker Hughes Incorporated Method and apparatus for preventing slug flow in pipelines
GB2500873A (en) * 2012-03-22 2013-10-09 Corac Energy Technologies Ltd Pipeline compression system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2979389A (en) * 1957-04-18 1961-04-11 Socony Mobil Oil Co Inc Apparatus for treating high pressure gas systems
US3644107A (en) * 1970-03-09 1972-02-22 Phillips Petroleum Co Method for preventing the formation of hydrates and ice
FR2196446A1 (en) * 1972-08-18 1974-03-15 Erdoelchemie Gmbh
GB2090642A (en) * 1980-12-09 1982-07-14 British Gas Corp Removal of Condensed Gas from the Walls of Gas Pipelines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2979389A (en) * 1957-04-18 1961-04-11 Socony Mobil Oil Co Inc Apparatus for treating high pressure gas systems
US3644107A (en) * 1970-03-09 1972-02-22 Phillips Petroleum Co Method for preventing the formation of hydrates and ice
FR2196446A1 (en) * 1972-08-18 1974-03-15 Erdoelchemie Gmbh
GB2090642A (en) * 1980-12-09 1982-07-14 British Gas Corp Removal of Condensed Gas from the Walls of Gas Pipelines

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0464797A1 (en) * 1990-07-05 1992-01-08 Linde Aktiengesellschaft Methode and device for introducing gas in a fluid
US8047292B2 (en) * 2004-12-06 2011-11-01 Baker Hughes Incorporated Method and apparatus for preventing slug flow in pipelines
GB2500873A (en) * 2012-03-22 2013-10-09 Corac Energy Technologies Ltd Pipeline compression system

Also Published As

Publication number Publication date
NO833013L (en) 1984-03-05

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19840622

STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19851008

RIN1 Information on inventor provided before grant (corrected)

Inventor name: GREGORY, GARRY A.

Inventor name: NICHOLSON, MURRAY K.

Inventor name: AZIZ, KHALID

Inventor name: NICKERSON, JOHN R.