RU2729566C1 - Device for underwater cooling of flow of hydrocarbon mixture and method of underwater cooling of flow of hydrocarbon mixture - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: disclosed are a method for underwater cooling of a stream of a hydrocarbon mixture and a device for its implementation, comprising a casing and a means of generating a stream of sea water, configured to direct a stream of sea water, wherein the casing comprises: sea water influx intensification pipes, lower belt, upper belt, middle belt with expansion, outlet hole of outlet pipeline; a supply pipeline, a discharge pipeline, a plurality of vertically arranged bundles of heat exchange tubes, wherein each of the plurality of heat exchange tube bundles comprises a plurality of first heat exchange sections, each of which contains plurality of second heat exchange sections, each of which contains plurality of heat exchange tubes; plurality of first upper headers and plurality of second upper headers; a plurality of first lower headers and a plurality of second lower headers; wherein plurality of bundles of heat exchange tubes, a plurality of manifolds, a supply pipeline and a discharge pipeline are configured to direct the hydrocarbon mixture flow in a direction opposite to the direction of the sea water flow, with provision of consistent uniform separation of said flow on heat exchange tubes after supply pipeline and connection of flow in front of discharge pipeline.

EFFECT: increase of heat flow through heat exchange surface due to provision of counterflow flow pattern of heat carriers, additional supply of colder flows of sea water through intermediate holes between inlet and outlet of housing with holes and providing uniform heat exchange on sections of cooler due to identical speeds of both flow of hydrocarbon mixture and flow of surrounding sea water.

6 cl, 8 dwg

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of heat and power engineering, namely to apparatus for underwater cooling of a hydrocarbon mixture, and can be used in oil production, gas production, oil refining, gas processing and other industries.

LEVEL OF TECHNOLOGY

A device related to an underwater heat exchanger and disclosed in WO 2010/002272 A1 (published 07.01.2010) is known from the prior art.

The heat exchanger known from the aforementioned document includes a convection heat exchange section in the form of a tube bundle, designed for heat exchange between the pumped fluid inside the tubes of the tube bundle and the surrounding water on the opposite side of the wall of the tubes of the tube bundle, as well as a convection heat exchange section with inlet and outlet for seawater, surrounded by a casing ... In addition, the known heat exchanger is provided with means for controlling the through-flow of the surrounding seawater from the seawater inlet to the seawater outlet in the form of a pump. By changing the speed of the pump drive or by controlling the throttle valve, the operator can control the rate of heat exchange between the fluid flowing through the convection heat exchange section and the seawater.

The disadvantages of this technical solution are: a significant decrease in heat transfer when the pump stops pumping seawater due to the lack of the required flow of seawater; ineffective use of the convective heat transfer process due to the presence of a shell with one inlet for seawater; non-use of the effect of increasing heat transfer due to counterflow between the flow of the hydrocarbon mixture and the coolant; uneven distribution of costs through heat exchange tubes; different flow rates in heat exchange tubes and inlet and outlet headers.

Also, from the document US 2012/0103621 A1 (published 03.05.2012) a subsea system with an subsea cooler and a method for cleaning the subsea cooler is known, which contains an subsea cooler and a compressor located in series in the flow line of the system. The known subsea system further comprises a recirculation line that is configured such that a portion of the compressor discharge line fluid is recirculated back to the subsea cooler feed line. The recirculation line is used to regulate the compressor capacity and clean the subsea cooler. The system provides several options for underwater coolers. In one embodiment, the cooler comprises a vertical pipeline connected to a supply pipeline. After the vertical pipeline, a distribution pipeline is installed, which divides the liquid flow in the vertical pipe into three branches. An intake manifold is connected to each branch of the distribution pipeline. Likewise, the subsea cooler includes a return line that is connected to an integrated manifold. Three exhaust manifolds are connected to the joint manifold and are preferably located at a lower position than the intake manifolds. Heat exchanger tubes run between the intake manifold and the exhaust manifold. The subsea chiller is configured so that the heat exchange tubes are exposed to the surrounding seawater. The heat exchange tubes are preferably installed vertically. The exhaust manifolds and intake manifolds are tilted relative to the horizontal plane. The nearly vertical configuration of the heat exchange tubes and the angled configuration of the outlet header and inlet header facilitate the removal of sand and deposits from the subsea cooler. The subsea chiller can have multiple cooling sections. The subsea chiller is equipped with valve devices that communicate with the control system to control and regulate flows. In another embodiment, the subsea cooler comprises eight cooling sections, each of which includes an intake manifold that has a rise and an outlet manifold. Heat exchange tubes are provided between the inlet manifold and the outlet manifold of each cooling section. The cooler works as follows. The liquid to be cooled flows through the riser pipe. In the upper part, the liquid stream is split and flows through four pipes to the distribution manifolds of the four cooling sections. Thereafter, the liquid flow is distributed to the cooling sections and flows down the heat exchange tubes, which are exposed to the surrounding seawater. The subsea chiller is equipped with one or more valve devices to control and regulate flows in each section. The disadvantages of the technical solutions known from the document US 2012/0103621 A1 are a significant decrease in heat transfer due to: the absence of forced movement of the flow of seawater; lack of directional flow with natural convection due to the absence of a casing; non-use of the counterflow effect between the flow of the hydrocarbon mixture and the coolant; different values of flow rates in heat exchange tubes, collectors and distribution pipelines; the formation of deposits and stagnant zones due to the presence of sharp changes in the direction of flow, when the horizontal supply pipeline turns into a vertical one.

Closest to the claimed invention is an underwater cooler known from document US 2010/0252227 A1 (published 07.10.2010).

Said subsea cooler has an inlet for a hot fluid flow, an outlet for chilled fluid, a cooling unit containing a plurality of heat exchange tube coils exposed to seawater to cool the hot fluid, and means for generating seawater flow through the coils. Said means for generating seawater flow through the coils consists of a propeller and a rotary actuator. The propeller is designed so that when it operates, it creates the desired flow of seawater through the coils located in the seawater. The cooling unit of a known cooler is enclosed in a jacket, or the coils of the cooling unit are located in the jacket. This configuration allows the flow of seawater to be directed through the coils of the heat exchange tubes. The disadvantages of this technical solution are: a significant decrease in heat transfer when the means for pumping sea water is stopped due to the lack of the required flow of sea water; ineffective use of the convective heat transfer process due to the presence of a shell with one inlet for seawater; non-use of the effect of increasing heat transfer due to counterflow between the flow of the hydrocarbon mixture and the coolant; uneven distribution of costs through heat exchange tubes; different flow rates in heat exchange tubes and inlet and outlet headers.

DISCLOSURE OF THE INVENTION

The technical problem to be solved by the claimed invention is the creation of a method for underwater cooling of a hydrocarbon mixture flow and a device for its implementation, the design features of which allow maximizing the cooling of the hydrocarbon mixture flow and increasing the efficiency of heat transfer between the pumped fluid as when a means of generating a flow of seawater is in operation, and when the seawater flow generating means is inoperative.

The mentioned technical problem is solved due to the fact that the claimed invention comprises a casing of a special design, which has an expansion and additional holes between the inlet and outlet of the casing with branch pipes, as well as vertical heat exchange sections, in which there is a uniform separation of costs while ensuring a close flow rate during all paths of the heat exchange bundle, while the fluid flow is directed through the heat exchange sections from top to bottom, and the generated flow of seawater - from bottom to top, thus providing a counterflow pattern of movement.

The technical result achieved by the implementation of the invention consists in increasing the heat flux through the heat exchange surface due to the provision of a countercurrent flow pattern of heat carriers, additional inflow of colder seawater flows through the openings with nozzles intermediate between the inlet and outlet of the casing, and ensuring uniform heat exchange along the sections of the cooler due to the same the velocities of both the flow of the hydrocarbon mixture and the flow of the surrounding seawater.

Also, through the claimed invention, an increase in the efficiency of heat exchange is achieved due to:

rectilinear configuration of the lower belt of the casing, which ensures flow stabilization for further rectilinear propagation along the heat exchange tubes,

an ascending orientation of the seawater supply pipes towards the casing, which ensures the movement of colder seawater masses inside the casing,

vertical arrangement of heat exchange tubes and casing, the presence of a forced flow of seawater, which minimizes the fouling of the device by marine organisms.

In addition, the vertical arrangement of the heat exchange tubes and the casing, as well as the location of the supply and discharge pipelines from diametrically opposite sides, allows for the possibility of a linear arrangement of the device relative to the associated equipment, which simplifies the layout at the station and ensures the optimization of the placement of the device at the station.

A leaky enclosure provides similar pressures inside and outside the enclosure, which minimizes enclosure wall thickness and simplifies manufacturing and installation.

The execution of the heat exchange sections in the form of identical modules ensures the unification of the coolers, while their mutual arrangement makes it possible to provide cavities for the vertical placement of supporting and bearing elements, which reduces the overall dimensions of the device.

In more detail, the specified problem and the claimed technical result are respectively solved and achieved due to the fact that the device for underwater cooling of the hydrocarbon mixture stream contains:

a casing and seawater flow generating means adapted to direct the seawater flow, wherein

the casing contains:

branch pipes for intensifying the inflow of sea water,

lower belt,

upper belt,

middle belt with extension,

hole for the outlet of the discharge pipeline;

supply pipeline,

outlet pipeline,

a lot of vertically arranged bundles of heat exchange tubes,

wherein each of the plurality of bundles of heat exchange tubes contains a plurality of first heat exchange sections, each of which contains a plurality of second heat exchange sections, each of which contains a plurality of heat exchange tubes;

a plurality of first top headers and a plurality of second top headers;

a plurality of first lower headers and a plurality of second lower headers;

in this case, a plurality of bundles of heat exchange tubes, a plurality of collectors, a supply pipeline and a discharge pipeline are configured to direct the flow of the hydrocarbon mixture in the direction opposite to the direction of the flow of seawater, ensuring successive uniform division of the specified flow along the heat exchange tubes after the supply pipeline and connecting the flow in front of the discharge pipeline ...

In addition, the specified problem and the claimed technical result are respectively solved and achieved due to the fact that the heat exchange tubes of each of the plurality of second heat exchange sections are located on the sides of the regular hexagon and in the center of this hexagon, the second heat exchange sections of each of the first heat exchange sections are located on the sides of the regular hexagon and in the center of this hexagon, the first heat exchange sections of each of the bundles of heat exchange tubes are located on the sides of the regular hexagon and in the center of this hexagon so as to form cavities adapted to accommodate supporting and bearing elements.

Also, the specified problem and the claimed technical result are respectively solved and achieved by means of a method for underwater cooling of a flow of a hydrocarbon mixture, containing the stages at which:

the flow of hydrocarbon mixture is supplied to the supply pipeline of the device for underwater cooling of the flow of the hydrocarbon mixture;

by means of the casing and the means for generating a stream of seawater of the device for underwater cooling of the stream of the hydrocarbon mixture, directing the stream of seawater;

sequentially direct the flow of the hydrocarbon mixture in the direction opposite to the direction of the flow of seawater through the supply pipeline, a plurality of first upper headers and a plurality of second upper headers of a device for underwater cooling of a hydrocarbon mixture stream, providing parallel separation of the hydrocarbon mixture flow for simultaneous passage through a plurality of heat exchange tubes of a plurality of second heat exchange sections of a plurality of first heat exchange sections of a plurality of bundles of heat exchange tubes of a device for underwater cooling of a hydrocarbon mixture stream;

sequentially directing a hydrocarbon mixture stream from a plurality of heat exchange tubes of a plurality of second heat exchange sections of a plurality of first heat exchange sections of a plurality of bundles of heat exchange tubes of a device for underwater cooling of a hydrocarbon mixture stream into a plurality of second lower headers and first lower headers to provide parallel connection of the hydrocarbon mixture stream;

the flow of the hydrocarbon mixture is directed after the parallel connection of the flow of the hydrocarbon mixture into the outlet pipeline of the device for underwater cooling of the flow of the hydrocarbon mixture.

Additionally, the specified problem and the claimed technical result are respectively solved and achieved due to the fact that the flow rates in the heat exchange tubes and each of the plurality of second upper and second lower manifolds of the device for underwater cooling of the hydrocarbon mixture stream are preferably equal.

Also, the specified problem and the claimed technical result are respectively solved and achieved due to the fact that the flow rates in each of the plurality of second upper and second lower headers and each of the plurality of first upper and first lower headers of the device for underwater cooling of the hydrocarbon mixture stream are predominantly equal.

BRIEF DESCRIPTION OF DRAWINGS

The above advantages of the invention will become more apparent from the following description of a preferred embodiment thereof, given with reference to the accompanying drawings, in which:

in fig. 1 shows a general view of a device for underwater cooling of a hydrocarbon mixture stream;

in fig. 2 shows a top view of a device for underwater cooling of a hydrocarbon mixture stream;

in fig. 3 shows heat exchange sections and a bundle of heat exchange tubes;

in fig. 4 shows a cross-section of a bundle of heat exchange tubes;

in fig. 5, 6 depict embodiments of the casing;

in fig. 7 shows means for generating a stream of seawater;

in fig. 8 illustrates a method for underwater cooling of a hydrocarbon mixture stream and a device for implementing said method.

CARRYING OUT THE INVENTION

An apparatus for underwater cooling of a hydrocarbon mixture stream and a method for underwater cooling of a hydrocarbon mixture stream in accordance with a preferred embodiment of the invention will now be described with reference to the accompanying drawings.

As shown in FIG. 1 and FIG. 2, a device for underwater cooling of a hydrocarbon mixture stream contains:

a plurality of bundles 1 of heat exchange tubes,

cover 2,

means 3 for generating a stream of seawater,

supply pipeline 4,

discharge line 5.

Additionally, the device for underwater cooling of the hydrocarbon mixture stream contains supporting and carrying elements (not shown in the figures).

FIG. 3, each of the plurality of heat exchange tube bundles 1 comprises a plurality of first heat exchange sections 6, each of which, in turn, comprises a plurality of second heat exchange sections 7. Each of the plurality of second heat exchange sections 7 contains a plurality of heat exchange tubes 8.

FIG. 4 is a cross-sectional view illustrating the relative position of the heat exchange tubes 8.

Heat exchange tubes 8 of each of the plurality of second heat exchange sections 7 are located on the sides of the regular hexagon and in the center of this hexagon, the second heat exchange sections 7 of each of the first heat exchange sections 6 are located on the sides of the regular hexagon and in the center of this hexagon, the first heat exchange sections 6 of each of the bundles 1 the heat exchange tubes are located on the sides of a regular hexagon and in the center of this hexagon.

Also in FIG. 4 shows the zone 10 of the location of the heat exchange tubes 8. With such a configuration of the inventive device for underwater cooling of the hydrocarbon mixture flow, the zones 9 provide for the location of the above-mentioned support and bearing elements, which are not conventionally shown.

The casing 2 is a diffuser and is shown schematically in FIG. 5 and FIG. 6.

Cover 2 contains:

branch pipes 11 for intensifying the inflow of sea water,

lower belt 12,

upper belt 13,

medium belt 14 with extension,

opening 15 for the outlet of the discharge pipeline from the heat exchange zone.

In a non-limiting embodiment of the invention, the cross-section of the flow section of the seawater stimulation pipes 11 may be circular. However, it will be obvious to a person skilled in the art that said cross-section can also have other shapes.

The branch pipe 11 for intensifying the inflow of seawater or part of it can be made in the form of a confuser 16, as shown in Fig. 6.

The seawater flow generating means 3 can be made in the form of a screw 17 with an electromechanical drive 18, as shown in FIG. 7.

The operation of a device for underwater cooling of a hydrocarbon mixture stream is schematically shown in FIG. 8.

To control the intensity of heat exchange between the stream 19 of the hydrocarbon mixture and the streams 20 and 21 of the surrounding seawater, means 3 for generating a stream of seawater are used, while increasing the heat flux, that is, maximizing the cooling of the stream 19 of the hydrocarbon mixture and, as a consequence, minimizing the surface area of the heat exchange tubes 8 use a counterflow pattern of movement, for which the heat exchange tubes 8 are placed vertically, that is, perpendicular to sea level, the flow 19 of the hydrocarbon mixture is directed from top to bottom, and to ensure the directed movement of flows 20 and 21 of sea water in the direction from bottom to top along heat exchange tubes 8, a casing 2 is used around a plurality of heat exchange tube bundles 1.

In this case, to ensure uniform distribution of the flow 19 of the hydrocarbon mixture through the heat exchange tubes 8 in order to maximize the cooling of the flow 19 of the hydrocarbon mixture by sequentially directing the flow 19 through the supply pipeline 4, a plurality of first upper headers 22, a plurality of second upper headers 23 sequentially divide the flow 19 of the hydrocarbon mixture for parallel passage through a plurality of heat exchange tubes 8 of a plurality of second heat transfer sections 7 of a plurality of first heat transfer sections 6 of a plurality of bundles 1 of heat transfer tubes.

Further, by means of a plurality of second lower headers 24, a plurality of first lower headers 25 perform parallel connection of the streams separated as described above in reverse order up to the discharge line 5.

The cross-sectional ratios of the heat exchange tubes 8, taking into account their number, with the cross-section of each of the plurality of second upper headers 23 and each of the plurality of second lower headers 24 are selected so as to ensure equal flow rates in the heat exchange tube 8 and headers 23 and 24.

The cross-sectional ratios of each of the plurality of second upper headers 23 and each of the plurality of second lower headers 24, taking into account the number of second heat exchange sections 7 with a cross-section of each of the plurality of first upper headers 22 and each of the plurality of first lower headers 25, is selected to provide equal values flow rates in headers 23 and 24 and headers 22 and 25.

This principle is followed for all heat exchange sections, inlet and outlet pipelines. The same flow rate 19 of the hydrocarbon mixture for all heat exchange tubes 8, including headers and supply and return pipelines, helps to maximize the cooling of the flow 19 of the hydrocarbon mixture by minimizing possible deposits on the walls on the inside of the tubes 8.

In order to maximize the cooling of the flow 19 of the hydrocarbon mixture, the casing 2 contains pipes 11 for intensifying the inflow of seawater. At the same time, in order to equalize the flow rate of seawater along the heat exchange tubes 8 in each cross-section of the casing 2 and provide an additional inflow of seawater with a lower temperature in order to maximize cooling of the flow 19 of the hydrocarbon mixture, the middle belt of the device containing the branch pipes 11 for intensifying the inflow of seawater is made with an expansion by such an amount that the additional inflow of sea water flow 21 does not cause changes in the speed of the total flow of sea water.

The use of a vertical arrangement of heat exchange tubes and the absence of a change in the direction of flow paths from horizontal or descending to ascending excludes the formation of stagnant zones and helps to remove condensate, hydrates and solid inclusions, which increases the efficiency of heat transfer.

The use of a vertical arrangement of heat exchange tubes in combination with a countercurrent flow pattern increases the efficiency of heat exchange when the seawater flow generating means 3 is operating.

The use of a vertical arrangement of heat exchange tubes in combination with a countercurrent flow pattern also provides a more efficient heat transfer under natural convection in the event of a non-working seawater flow generating means 3.

It should be understood that the preferred embodiment described above by way of example does not limit the scope of the present invention. After reading the present description, those skilled in the art can suggest many changes and additions to the described embodiments, all of which will fall within the scope of the invention as defined by the following claims.

Claims (25)

1. A device for underwater cooling of a hydrocarbon mixture stream, comprising: a casing and seawater flow generating means adapted to direct the seawater flow, wherein the casing contains: branch pipes for intensifying the inflow of sea water, lower belt, upper belt, middle belt with extension, hole for the outlet of the discharge pipeline; supply pipeline, outlet pipeline, a lot of vertically arranged bundles of heat exchange tubes, wherein each of the plurality of bundles of heat exchange tubes contains a plurality of first heat exchange sections, each of which contains a plurality of second heat exchange sections, each of which contains a plurality of heat exchange tubes; a plurality of first top headers and a plurality of second top headers; a plurality of first lower headers and a plurality of second lower headers; in this case, a plurality of bundles of heat exchange tubes, a plurality of collectors, a supply pipeline and a discharge pipeline are configured to direct the flow of the hydrocarbon mixture in the direction opposite to the direction of the flow of seawater, ensuring successive uniform division of the specified flow along the heat exchange tubes after the supply pipeline and connecting the flow in front of the discharge pipeline ... 2. The device according to claim. 1, characterized in that the heat exchange tubes of each of the plurality of second heat exchange sections are located on the sides of the regular hexagon and in the center of this hexagon, the second heat exchange sections of each of the first heat exchange sections are located on the sides of the regular hexagon and in the center of the given hexagon, the first heat exchange sections of each of the bundles of heat exchange tubes are located on the sides of the regular hexagon and in the center of this hexagon so as to form cavities made with the possibility of accommodating supporting and bearing elements. 3. The device according to claim 1, characterized in that the casing and the means for generating the flow of seawater are made with the possibility of directing the flow of seawater from bottom to top, and a plurality of bundles of heat exchange tubes, a plurality of collectors, a supply pipeline and a discharge pipeline are configured to direct the flow of hydrocarbon mix from top to bottom. 4. A method for underwater cooling of a hydrocarbon mixture stream, comprising: the flow of the hydrocarbon mixture is fed into the supply pipeline of the device for underwater cooling of the flow of the hydrocarbon mixture; by means of the casing and the means for generating a stream of seawater of the device for underwater cooling of the stream of the hydrocarbon mixture, directing the stream of seawater; sequentially direct the flow of the hydrocarbon mixture in the direction opposite to the direction of the flow of seawater through the supply pipeline, a plurality of first upper headers and a plurality of second upper headers of a device for underwater cooling of a hydrocarbon mixture stream, providing parallel separation of the hydrocarbon mixture flow for simultaneous passage through a plurality of heat exchange tubes of a plurality of second heat exchange sections of a plurality of first heat exchange sections of a plurality of bundles of heat exchange tubes of a device for underwater cooling of a hydrocarbon mixture stream; sequentially directing a stream of hydrocarbon mixture from a plurality of heat exchange tubes of a plurality of second heat exchange sections of a plurality of first heat exchange sections of a plurality of bundles of heat exchange tubes of a device for underwater cooling of a hydrocarbon mixture stream to a plurality of second lower headers and first lower headers to provide parallel connection of the hydrocarbon mixture stream; the flow of the hydrocarbon mixture is directed after the parallel connection of the flow of the hydrocarbon mixture into the outlet pipeline of the device for underwater cooling of the flow of the hydrocarbon mixture. 5. A method according to claim 3, characterized in that the flow rates in the heat exchange tubes and each of the plurality of second upper and second lower headers of the device for underwater cooling of the hydrocarbon mixture stream are advantageously equal. 6. The method of claim 3, wherein the flow rates in each of the plurality of second upper and second lower headers and each of the plurality of first upper and first lower headers of the apparatus for underwater cooling of the hydrocarbon mixture stream are advantageously equal.

Images