CA2785763A1 - Control of subsea compressors - Google Patents
Control of subsea compressors Download PDFInfo
- Publication number
- CA2785763A1 CA2785763A1 CA2785763A CA2785763A CA2785763A1 CA 2785763 A1 CA2785763 A1 CA 2785763A1 CA 2785763 A CA2785763 A CA 2785763A CA 2785763 A CA2785763 A CA 2785763A CA 2785763 A1 CA2785763 A1 CA 2785763A1
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- Canada
- Prior art keywords
- liquid
- compressor
- atomiser
- sensor means
- scrubber
- 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.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D31/00—Pumping liquids and elastic fluids at the same time
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means, e.g. by light scattering, diffraction, holography or imaging
- G01N15/0227—Investigating particle size or size distribution by optical means, e.g. by light scattering, diffraction, holography or imaging using imaging, e.g. a projected image of suspension; using holography
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D13/00—Pumping installations or systems
- F04D13/02—Units comprising pumps and their driving means
- F04D13/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D13/08—Units comprising pumps and their driving means the pump being electrically driven for submerged use
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0686—Units comprising pumps and their driving means the pump being electrically driven specially adapted for submerged use
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/009—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by bleeding, by passing or recycling fluid
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/70—Suction grids; Strainers; Dust separation; Cleaning
- F04D29/701—Suction grids; Strainers; Dust separation; Cleaning especially adapted for elastic fluid pumps
- F04D29/705—Adding liquids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/02—Surge control
- F04D27/0207—Surge control by bleeding, bypassing or recycling fluids
- F04D27/0223—Control schemes therefor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/02—Surge control
- F04D27/0292—Stop safety or alarm devices, e.g. stop-and-go control; Disposition of check-valves
Abstract
System for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary. The control system comprises a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means operatively connected to the sensor means for operation of the control means based on input from the sensor means. Method for control of a subsea located compressor.
Description
CONTROL OF SUBSEA COMPRESSORS
Field of the invention The present invention relates to compressors. More specifically, the present invention relates to a subsea located compressor that can operate in order to compress gas provided a liquid contents in the gas inlet flow is below a maximum limit.
Background of the invention and prior art Compressors are well known technology having numerous applications. It is also known that compressors will be damaged if the compressor blades, rotating at high speed, are hit by heavy objects. Such heavy objects include excessive quantities of oil drops and water drops. Accordingly, a compressor can only operate reliably if the liquid contents of the gas to be compressed is within a maximum acceptable limit.
For compressors operating on dry sites, such as industrial sites, the liquid contents can be separated out from the inlet gas. The separated liquid can be used for any convenient purpose or be discharged after being cleaned if required.
For a compressor located subsea, neither of separation, use and discharge of the liquid is straightforward. The actual location of the compressor can be tens or hundreds of kilometers away from land or surface installations and the depth can be hundreds of meters. Use of the separated liquid, typically oil and possibly water, requires huge investments in equipment and pipes. Discharge of the oil will violate regulations. The equipment for subsea separation and cleaning is very expensive. Currently, collection of sample bottles with an ROV
(remotely operated vehicle) and nuclear density gauges are the techniques for determination of liquid in gas volume fraction. The above mentioned high cost and limited availability of technology are disadvantages of the prior art subsea compression technology.
Field of the invention The present invention relates to compressors. More specifically, the present invention relates to a subsea located compressor that can operate in order to compress gas provided a liquid contents in the gas inlet flow is below a maximum limit.
Background of the invention and prior art Compressors are well known technology having numerous applications. It is also known that compressors will be damaged if the compressor blades, rotating at high speed, are hit by heavy objects. Such heavy objects include excessive quantities of oil drops and water drops. Accordingly, a compressor can only operate reliably if the liquid contents of the gas to be compressed is within a maximum acceptable limit.
For compressors operating on dry sites, such as industrial sites, the liquid contents can be separated out from the inlet gas. The separated liquid can be used for any convenient purpose or be discharged after being cleaned if required.
For a compressor located subsea, neither of separation, use and discharge of the liquid is straightforward. The actual location of the compressor can be tens or hundreds of kilometers away from land or surface installations and the depth can be hundreds of meters. Use of the separated liquid, typically oil and possibly water, requires huge investments in equipment and pipes. Discharge of the oil will violate regulations. The equipment for subsea separation and cleaning is very expensive. Currently, collection of sample bottles with an ROV
(remotely operated vehicle) and nuclear density gauges are the techniques for determination of liquid in gas volume fraction. The above mentioned high cost and limited availability of technology are disadvantages of the prior art subsea compression technology.
There is a demand for both a system and a method for control of a subsea located compressor, providing improvements with respect to the disadvantages mentioned above.
Summary of the invention The demand is met with the present invention.
More specifically, the invention -provides a system for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary. The control system comprises a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means operatively connected to the sensor means for operation of the control means based on input from the sensor means.
In a preferable embodiment the system comprises:
a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means for control of the inlet flow, operatively arranged to the inlet line upstream of the sensor means, said control means is operatively connected to the sensor means for operation of the control means based on input from the sensor means.
The sensor means is preferably an optical sensor using dark-field illumination with objective and camera arranged between a multitude of light sources, arranged outside of or including a window to be arranged in the pipe wall. The sensor is the subject matter of parallel patent application NO 2009 3598 to which it is referred for further information. Alternatively, the sensor is according to the teaching of EP 1159599.
Summary of the invention The demand is met with the present invention.
More specifically, the invention -provides a system for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary. The control system comprises a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means operatively connected to the sensor means for operation of the control means based on input from the sensor means.
In a preferable embodiment the system comprises:
a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means for control of the inlet flow, operatively arranged to the inlet line upstream of the sensor means, said control means is operatively connected to the sensor means for operation of the control means based on input from the sensor means.
The sensor means is preferably an optical sensor using dark-field illumination with objective and camera arranged between a multitude of light sources, arranged outside of or including a window to be arranged in the pipe wall. The sensor is the subject matter of parallel patent application NO 2009 3598 to which it is referred for further information. Alternatively, the sensor is according to the teaching of EP 1159599.
The control means preferably comprises at least one of an atomiser or injection mixer or ejector; a gas scrubber or separator further upstream separating and retaining liquid contents from the inlet flow, and a line arranged for injecting and mixing retained liquid back into the inlet flow, via the atomiser or injection mixer or ejector, as small droplets of size distribution and liquid volume fraction within a maximum acceptable limit, a switch or speed control operatively connected to the subsea compressor. Accordingly, the control means can stop or reduce the speed of the compressor, or the control means can affect the droplet size distribution and liquid volume fraction of the inlet line to the compressor.
Preferably, the atomiser or injection mixer uses the venturi effect in order to draw in liquid. The injection mixer can be a ProPure injection mixer.
Preferably a line with high pressure gas from the outlet side of the compressor is fed back to the injection mixer or atomiser in order to draw in liquid and achieve a good mixing or atomisation. An injection pump and a control valve are preferably arranged in the line for liquid from the scrubber or separator.
Preferably a scrubber is arranged in the inlet line, a liquid level sensor is arranged in the scrubber, a gas outlet from the scrubber includes an atomiser or injection mixer upstream of a sensor means in the inlet line to the compressor, the atomiser or injection mixer is operatively connected to a control device and the atomiser or injection mixer is fluidly connected to the outlet side of the compressor and to a liquid outlet from the scrubber.
Preferably, the atomiser or injection mixer is arranged immediately upstream of the compressor, for example within a distance of two inlet pipe diameters, with only the sensor in between the compressor and atomiser or injection mixer.
This is preferable in order to avoid coalescence or similar effect by the droplets and avoid precipitation of droplets on surfaces before reaching the compressor.
Preferably, the gas inlet line includes a flow rate and/or flow velocity meter, which makes it easier to relate the droplet size distribution and the liquid volume fraction to the impact effect of the liquid contents on the compressor, and improves the quality of the calculations. Preferably, the flow meter is integrated as a venturi flow meter as a part of the injection mixer or atomiser. A
separate measurement of flow rate, combined with the measurements of the optical darkfield sensor of droplet size and thereby droplet size distribution and liquid volume fraction or droplet density, facilitates the processing of the measured data in order to calculate the impact effect of the liquid contents, in order to ensure that the liquid contents is below the acceptable limit. Alternatively, the parameters are calculated only based on data from the darkfield sensor, for example by taking many representative droplet pictures, thereby finding liquid volume fraction, and determining droplet movement as a function of time, thereby finding flow rate and velocity.
The invention also provides a method for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary. The method comprises measuring and/or determining the liquid droplet size distribution and liquid volume fraction by using a sensor means operatively arranged to the inlet line, and operating the subsea compressor or control means or equipment upstream of the compressor based on input of the sensor means.
The method preferably comprises the step:
operating a control means arranged to the inlet line upstream of the sensor means, based on input form the sensor means, so as to ensure that the liquid contents of the inlet flow is within a maximum acceptable limit.
The amount of liquid that a compressor can operate with depends on the droplet size. As large droplets have higher momentum than small droplets, they cause more damage. Field tests have shown that a compressor can operate with several percent of liquid content indefinitely as long as the droplet size is very small. This is indicated principally in figure 1. As the momentum of each droplet also depends on the gas velocity, this also needs to be taken into account. If the gas velocity is not available, a default value is used instead in the calculations.
Preferably, the atomiser or injection mixer uses the venturi effect in order to draw in liquid. The injection mixer can be a ProPure injection mixer.
Preferably a line with high pressure gas from the outlet side of the compressor is fed back to the injection mixer or atomiser in order to draw in liquid and achieve a good mixing or atomisation. An injection pump and a control valve are preferably arranged in the line for liquid from the scrubber or separator.
Preferably a scrubber is arranged in the inlet line, a liquid level sensor is arranged in the scrubber, a gas outlet from the scrubber includes an atomiser or injection mixer upstream of a sensor means in the inlet line to the compressor, the atomiser or injection mixer is operatively connected to a control device and the atomiser or injection mixer is fluidly connected to the outlet side of the compressor and to a liquid outlet from the scrubber.
Preferably, the atomiser or injection mixer is arranged immediately upstream of the compressor, for example within a distance of two inlet pipe diameters, with only the sensor in between the compressor and atomiser or injection mixer.
This is preferable in order to avoid coalescence or similar effect by the droplets and avoid precipitation of droplets on surfaces before reaching the compressor.
Preferably, the gas inlet line includes a flow rate and/or flow velocity meter, which makes it easier to relate the droplet size distribution and the liquid volume fraction to the impact effect of the liquid contents on the compressor, and improves the quality of the calculations. Preferably, the flow meter is integrated as a venturi flow meter as a part of the injection mixer or atomiser. A
separate measurement of flow rate, combined with the measurements of the optical darkfield sensor of droplet size and thereby droplet size distribution and liquid volume fraction or droplet density, facilitates the processing of the measured data in order to calculate the impact effect of the liquid contents, in order to ensure that the liquid contents is below the acceptable limit. Alternatively, the parameters are calculated only based on data from the darkfield sensor, for example by taking many representative droplet pictures, thereby finding liquid volume fraction, and determining droplet movement as a function of time, thereby finding flow rate and velocity.
The invention also provides a method for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary. The method comprises measuring and/or determining the liquid droplet size distribution and liquid volume fraction by using a sensor means operatively arranged to the inlet line, and operating the subsea compressor or control means or equipment upstream of the compressor based on input of the sensor means.
The method preferably comprises the step:
operating a control means arranged to the inlet line upstream of the sensor means, based on input form the sensor means, so as to ensure that the liquid contents of the inlet flow is within a maximum acceptable limit.
The amount of liquid that a compressor can operate with depends on the droplet size. As large droplets have higher momentum than small droplets, they cause more damage. Field tests have shown that a compressor can operate with several percent of liquid content indefinitely as long as the droplet size is very small. This is indicated principally in figure 1. As the momentum of each droplet also depends on the gas velocity, this also needs to be taken into account. If the gas velocity is not available, a default value is used instead in the calculations.
Normally there will be a range of droplet sizes present. From the sensor signals, droplet size statistics are collected for a number of droplets. The statistics are divided into size groups. The statistics are then further converted into momentum using the gas velocity, and for each group it is verified that the concentration does not exceed the allowed maximum limit from Fig 1. The distributed droplet size fractions are preferably summarized to 1 or below, whereby 1 denotes the maximum allowable amount for a specific droplet size.
Preferably, liquid is retained in a scrubber upstream of the sensor means, at excessive liquid level in the scrubber liquid is injected into the inlet line via an atomiser or injection mixer between the scrubber and sensor means, the liquid is drawn into the atomiser or injection mixer by the venturi effect.
Preferably high pressure gas from the outlet side of the compressor, as delivered through a line from the compressor outlet line to the atomiser or injection mixer, preferably with a control valve in the line, is used to facilitate drawing in liquid.
Pumping is preferably an additional, supplementary or replacing way of injecting liquid into the inlet flow to the compressor.
The'invention also provides use of an optical dark field sensor for measuring and determining the liquid droplet size distribution and liquid volume fraction upstream of a subsea compressor. Preferably, the measurement results are used for control of the subsea compressor or control means or equipment upstream of the compressor.
Figures The invention is illustrated by two figures, of which Fig. 1 illustrates the maximum allowable liquid contents, and Fig. 2 illustrates an embodiment of the system of the invention.
Detailed description Reference is made to Fig. 1, illustrating how the compressor can tolerate a liquid content for an average droplet size; the maximum limit is represented by a dotted line. For average droplet size below 20 micron, 10 % liquid content can be tolerated, for larger average droplet sizes the maximum tolerable limit drops as a straight line. However, the droplets will typically have a distribution, but if the distribution and type of liquid is consistent, the model based on average droplet size is useful. Further, the velocity and flow rate in the inlet line to the compressor will also affect the maximum limit, but the speed of the compressor blades or rotors is very high compared to the velocity of the droplets, the directions of movement being perpendicular initially, which limits the effect of the velocity in the inlet pipe. Both droplet velocity and droplet size distribution are factors that should be paid particular attention if they vary outside appropriate limits, that is, if they vary so much that the operation is significantly affected.
Further reference is made to Fig. 2, illustrating a system of the present invention. More specifically, a system 6 for control of a subsea located compressor 5 fluidly connected to receive an inlet flow of gas through an inlet line 7 is illustrated, said flow may include liquid in an amount that may vary. The system comprises a sensor means 2 for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means 3,4 for control of the inlet flow, operatively arranged to the inlet line upstream of the sensor means, said control means is operatively connected to the sensor means for operation of the control means based on input from the sensor means. The illustrated control means comprises an atomiser 3, arranged in the inlet line 7, and an injection pump and/or control valve 4, and associated control units. The control element 4 may also be an ejector or eductor type device, with modulating control via a control valve in the gas line. Also a scrubber 8 with a level sensor 1 is illustrated. A liquid outlet line is arranged from a bottom level of the scrubber to the injection pump 4 and/
or control valve 4. A line for supply of high pressure gas is arranged from the outlet side of the compressor to the control valve 4. The liquid from the bottom of the scrubber and the high pressure gas from the outlet side of the compressor are transferred independently but in parallel lines from the control means 4 to the atomiser 3, where said liquid is broken up to droplets of microns sizes, aided by the turbulence generated with the high pressure gas. The injection rate of liquid and the feedback flow of high pressure gas are regulated by injection pump 4 and control valve 4, respectively, which units are illustrated as one unit on Fig.
2. The line transferring liquid may in addition to or as a replacement to the injection pump include a injection control valve. However, a PID level controller LC, taking input from level senor 1 at the scrubber, has a fixed level setpoint. If the level exceeds this setpoint, an output signal increases, which increase results in energising the injection pump 4 for transfer of accumulated liquid back into the gas inlet line via the atomiser 3. Accordingly, the accumulated liquid is reinjected into the inlet flow, the mixing and dispersion into droplets of micron sizes are facilitated by the reflux or feedback flow of high pressure gas from the outlet side of the compressor. However, the sensor 2 measures the average droplet size, the droplet size distribution and the liquid volume fraction. A
CALC
element determines, based on input from the sensor, whether the compressor operates safely or beyond the maximum acceptable limit of liquid contents. If the operation is beyond the limit, based on input from the CALC element, a HILIM element will reduce the reinjection of liquid by reducing the signal to the control means 4. Alternatively no high pressure gas is fed back to the injection mixer or atomiser, in which case only an injection pump may be sufficient in the liquid reinjection line, in addition to associated control units.
The system of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention. The method of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention. The use of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention.
Preferably, liquid is retained in a scrubber upstream of the sensor means, at excessive liquid level in the scrubber liquid is injected into the inlet line via an atomiser or injection mixer between the scrubber and sensor means, the liquid is drawn into the atomiser or injection mixer by the venturi effect.
Preferably high pressure gas from the outlet side of the compressor, as delivered through a line from the compressor outlet line to the atomiser or injection mixer, preferably with a control valve in the line, is used to facilitate drawing in liquid.
Pumping is preferably an additional, supplementary or replacing way of injecting liquid into the inlet flow to the compressor.
The'invention also provides use of an optical dark field sensor for measuring and determining the liquid droplet size distribution and liquid volume fraction upstream of a subsea compressor. Preferably, the measurement results are used for control of the subsea compressor or control means or equipment upstream of the compressor.
Figures The invention is illustrated by two figures, of which Fig. 1 illustrates the maximum allowable liquid contents, and Fig. 2 illustrates an embodiment of the system of the invention.
Detailed description Reference is made to Fig. 1, illustrating how the compressor can tolerate a liquid content for an average droplet size; the maximum limit is represented by a dotted line. For average droplet size below 20 micron, 10 % liquid content can be tolerated, for larger average droplet sizes the maximum tolerable limit drops as a straight line. However, the droplets will typically have a distribution, but if the distribution and type of liquid is consistent, the model based on average droplet size is useful. Further, the velocity and flow rate in the inlet line to the compressor will also affect the maximum limit, but the speed of the compressor blades or rotors is very high compared to the velocity of the droplets, the directions of movement being perpendicular initially, which limits the effect of the velocity in the inlet pipe. Both droplet velocity and droplet size distribution are factors that should be paid particular attention if they vary outside appropriate limits, that is, if they vary so much that the operation is significantly affected.
Further reference is made to Fig. 2, illustrating a system of the present invention. More specifically, a system 6 for control of a subsea located compressor 5 fluidly connected to receive an inlet flow of gas through an inlet line 7 is illustrated, said flow may include liquid in an amount that may vary. The system comprises a sensor means 2 for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means 3,4 for control of the inlet flow, operatively arranged to the inlet line upstream of the sensor means, said control means is operatively connected to the sensor means for operation of the control means based on input from the sensor means. The illustrated control means comprises an atomiser 3, arranged in the inlet line 7, and an injection pump and/or control valve 4, and associated control units. The control element 4 may also be an ejector or eductor type device, with modulating control via a control valve in the gas line. Also a scrubber 8 with a level sensor 1 is illustrated. A liquid outlet line is arranged from a bottom level of the scrubber to the injection pump 4 and/
or control valve 4. A line for supply of high pressure gas is arranged from the outlet side of the compressor to the control valve 4. The liquid from the bottom of the scrubber and the high pressure gas from the outlet side of the compressor are transferred independently but in parallel lines from the control means 4 to the atomiser 3, where said liquid is broken up to droplets of microns sizes, aided by the turbulence generated with the high pressure gas. The injection rate of liquid and the feedback flow of high pressure gas are regulated by injection pump 4 and control valve 4, respectively, which units are illustrated as one unit on Fig.
2. The line transferring liquid may in addition to or as a replacement to the injection pump include a injection control valve. However, a PID level controller LC, taking input from level senor 1 at the scrubber, has a fixed level setpoint. If the level exceeds this setpoint, an output signal increases, which increase results in energising the injection pump 4 for transfer of accumulated liquid back into the gas inlet line via the atomiser 3. Accordingly, the accumulated liquid is reinjected into the inlet flow, the mixing and dispersion into droplets of micron sizes are facilitated by the reflux or feedback flow of high pressure gas from the outlet side of the compressor. However, the sensor 2 measures the average droplet size, the droplet size distribution and the liquid volume fraction. A
CALC
element determines, based on input from the sensor, whether the compressor operates safely or beyond the maximum acceptable limit of liquid contents. If the operation is beyond the limit, based on input from the CALC element, a HILIM element will reduce the reinjection of liquid by reducing the signal to the control means 4. Alternatively no high pressure gas is fed back to the injection mixer or atomiser, in which case only an injection pump may be sufficient in the liquid reinjection line, in addition to associated control units.
The system of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention. The method of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention. The use of the invention can be combined with features as described or illustrated in this document in any operative combination, which combinations are embodiments of the present invention.
Claims (9)
1.
System for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary, characterised in that it comprises a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means operatively connected to the sensor means for operation of the control means based on input from the sensor means.
System for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary, characterised in that it comprises a sensor means for measuring and determining the liquid droplet size distribution and liquid volume fraction, operatively arranged to the inlet line, and a control means operatively connected to the sensor means for operation of the control means based on input from the sensor means.
2.
System according to claim 1, characterised in that the sensor means is an optical sensor using dark-field illumination with objective and camera arranged between a multitude of light sources, arranged outside of or including a window to be arranged in the pipe wall.
System according to claim 1, characterised in that the sensor means is an optical sensor using dark-field illumination with objective and camera arranged between a multitude of light sources, arranged outside of or including a window to be arranged in the pipe wall.
3.
System according to claim 1, characterised in that the control means comprises at least one of an atomiser or injection mixer, a gas scrubber or separator further upstream separating and retaining liquid contents from the inlet flow, and a line arranged for injecting and mixing retained liquid back into the inlet flow, via the atomiser or injection mixer, as small droplets of size distribution and liquid volume fraction within a maximum acceptable limit.
System according to claim 1, characterised in that the control means comprises at least one of an atomiser or injection mixer, a gas scrubber or separator further upstream separating and retaining liquid contents from the inlet flow, and a line arranged for injecting and mixing retained liquid back into the inlet flow, via the atomiser or injection mixer, as small droplets of size distribution and liquid volume fraction within a maximum acceptable limit.
4.
System according to claim 1, characterised in that a scrubber is arranged in the inlet line, a liquid level sensor is arranged in the scrubber, a gas outlet from the scrubber includes an atomiser or injection mixer upstream of a sensor means in the inlet line to the compressor, the atomiser or injection mixer is operatively connected to a control device and the atomiser or injection mixer is fluidly connected to the outlet side of the compressor and to a liquid outlet from the scrubber.
System according to claim 1, characterised in that a scrubber is arranged in the inlet line, a liquid level sensor is arranged in the scrubber, a gas outlet from the scrubber includes an atomiser or injection mixer upstream of a sensor means in the inlet line to the compressor, the atomiser or injection mixer is operatively connected to a control device and the atomiser or injection mixer is fluidly connected to the outlet side of the compressor and to a liquid outlet from the scrubber.
5.
Method for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary, characterised in that it comprises measuring and determining the liquid droplet size distribution and liquid volume fraction by using a sensor means operatively arranged to the inlet line, and operating the subsea compressor or control means or equipment upstream of the compressor based on input of the sensor means.
Method for control of a subsea located compressor fluidly connected to receive an inlet flow of gas through an inlet line, said flow may include liquid in an amount that may vary, characterised in that it comprises measuring and determining the liquid droplet size distribution and liquid volume fraction by using a sensor means operatively arranged to the inlet line, and operating the subsea compressor or control means or equipment upstream of the compressor based on input of the sensor means.
6.
Method according to claim 5, characterised in that the distributed droplet size fractions are summarized to 1 or below, whereby 1 denotes the maximum allowable amount for a specific droplet size.
Method according to claim 5, characterised in that the distributed droplet size fractions are summarized to 1 or below, whereby 1 denotes the maximum allowable amount for a specific droplet size.
7.
Method according to claim 5, characterised in that liquid is retained in a scrubber upstream of the sensor means, at excessive liquid level in the scrubber liquid is injected into the inlet line via an atomiser or injection mixer between the scrubber and sensor means, the liquid is drawn into the atomiser or injection mixer by the venturi effect.
Method according to claim 5, characterised in that liquid is retained in a scrubber upstream of the sensor means, at excessive liquid level in the scrubber liquid is injected into the inlet line via an atomiser or injection mixer between the scrubber and sensor means, the liquid is drawn into the atomiser or injection mixer by the venturi effect.
8.
Method according to claim 7, characterised in that high pressure gas from the outlet side of the compressor, as delivered through a line from the compressor outlet line to the atomiser or injection mixer, is used to facilitate drawing in liquid.
Method according to claim 7, characterised in that high pressure gas from the outlet side of the compressor, as delivered through a line from the compressor outlet line to the atomiser or injection mixer, is used to facilitate drawing in liquid.
9.
Use of an optical dark field sensor for measuring and determining the liquid droplet size distribution and liquid volume fraction upstream of a subsea compressor.
Use of an optical dark field sensor for measuring and determining the liquid droplet size distribution and liquid volume fraction upstream of a subsea compressor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20093599 | 2009-12-29 | ||
| NO20093599A NO331264B1 (en) | 2009-12-29 | 2009-12-29 | System and method for controlling a submarine located compressor, and using an optical sensor thereto |
| PCT/NO2010/000477 WO2011081528A1 (en) | 2009-12-29 | 2010-12-20 | Control of subsea compressors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2785763A1 true CA2785763A1 (en) | 2011-07-07 |
Family
ID=44226673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2785763A Abandoned CA2785763A1 (en) | 2009-12-29 | 2010-12-20 | Control of subsea compressors |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US9382921B2 (en) |
| AU (1) | AU2010337436B2 (en) |
| BR (1) | BR112012016046A2 (en) |
| CA (1) | CA2785763A1 (en) |
| GB (1) | GB2488300B (en) |
| MY (1) | MY183644A (en) |
| NO (1) | NO331264B1 (en) |
| RU (1) | RU2556955C2 (en) |
| WO (1) | WO2011081528A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9382920B2 (en) * | 2011-11-14 | 2016-07-05 | General Electric Company | Wet gas compression systems with a thermoacoustic resonator |
| CN103047190A (en) * | 2012-04-17 | 2013-04-17 | 溧阳德维透平机械有限公司 | Centrifugal compressor |
| ITFI20120125A1 (en) * | 2012-06-19 | 2013-12-20 | Nuovo Pignone Srl | "WET GAS COMPRESSOR AND METHOD" |
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| US5347467A (en) * | 1992-06-22 | 1994-09-13 | Compressor Controls Corporation | Load sharing method and apparatus for controlling a main gas parameter of a compressor station with multiple dynamic compressors |
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| US5815264A (en) * | 1994-09-21 | 1998-09-29 | Laser Sensor Technology, Inc | System for acquiring an image of a multi-phase fluid by measuring backscattered light |
| US5490562A (en) * | 1995-02-07 | 1996-02-13 | Paragon Engineering Services Incorporated | Subsea flow enhancer |
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| US6039116A (en) * | 1998-05-05 | 2000-03-21 | Atlantic Richfield Company | Oil and gas production with periodic gas injection |
| US6153873A (en) * | 1998-05-20 | 2000-11-28 | E. I. Dupont De Numours And Company | Optical probe having an imaging apparatus |
| GB9902549D0 (en) | 1999-02-05 | 1999-03-24 | Jorin Limited | Apparatus for and method of monitoring particulate material in a fluid |
| EP1242745A1 (en) * | 1999-12-31 | 2002-09-25 | Shell Internationale Researchmaatschappij B.V. | Method and system for optimizing the performance of a rotodynamic multi-phase flow booster |
| US6296060B1 (en) * | 2000-01-10 | 2001-10-02 | Kerr-Mcgee Corporation | Methods and systems for producing off-shore deep-water wells |
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| GB2371858B (en) * | 2001-02-05 | 2004-10-13 | Abb Offshore Systems Ltd | Monitoring particles in a fluid flow |
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| NO325930B1 (en) * | 2006-07-07 | 2008-08-18 | Shell Int Research | Process for processing and separating a multi-phase well flow mixture |
| NO326079B1 (en) * | 2006-07-07 | 2008-09-15 | Shell Int Research | Process for treating and separating a multi-phase well flow mixture. |
| NO327253B1 (en) * | 2006-10-10 | 2009-05-25 | Aker Subsea As | Method and system for controlling fluid level in a tank |
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| EP2233745A1 (en) * | 2009-03-10 | 2010-09-29 | Siemens Aktiengesellschaft | Drain liquid relief system for a subsea compressor and a method for draining the subsea compressor |
| NO20093598A1 (en) | 2009-12-29 | 2011-06-30 | Aker Subsea As | Optical particle templates |
-
2009
- 2009-12-29 NO NO20093599A patent/NO331264B1/en unknown
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- 2010-12-20 BR BR112012016046A patent/BR112012016046A2/en not_active IP Right Cessation
- 2010-12-20 RU RU2012132021/06A patent/RU2556955C2/en not_active IP Right Cessation
- 2010-12-20 AU AU2010337436A patent/AU2010337436B2/en not_active Ceased
- 2010-12-20 CA CA2785763A patent/CA2785763A1/en not_active Abandoned
- 2010-12-20 WO PCT/NO2010/000477 patent/WO2011081528A1/en active Application Filing
- 2010-12-20 MY MYPI2012002783A patent/MY183644A/en unknown
- 2010-12-20 GB GB1210725.6A patent/GB2488300B/en not_active Expired - Fee Related
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| RU2556955C2 (en) | 2015-07-20 |
| GB201210725D0 (en) | 2012-08-01 |
| GB2488300A (en) | 2012-08-22 |
| MY183644A (en) | 2021-03-04 |
| BR112012016046A2 (en) | 2016-08-16 |
| US20120257990A1 (en) | 2012-10-11 |
| WO2011081528A1 (en) | 2011-07-07 |
| NO331264B1 (en) | 2011-11-14 |
| AU2010337436A1 (en) | 2012-07-05 |
| NO20093599A1 (en) | 2011-06-30 |
| GB2488300B (en) | 2014-07-09 |
| US9382921B2 (en) | 2016-07-05 |
| RU2012132021A (en) | 2014-02-10 |
| AU2010337436B2 (en) | 2014-09-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |
Effective date: 20151116 |
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| FZDE | Discontinued |
Effective date: 20180704 |