WO2016096164A1

WO2016096164A1 - Heated crude oil pipeline

Info

Publication number: WO2016096164A1
Application number: PCT/EP2015/062435
Authority: WO
Inventors: Chan KI
Original assignee: Quantum Technology Group (Singapore) Pte. Ltd.
Priority date: 2014-12-15
Filing date: 2015-06-03
Publication date: 2016-06-23

Abstract

A pipeline system with a heat transfer assembly for heating a fluid flowing via a pipeline segment (100) is particularly efficient if the heat transfer assembly comprises at least a first stack of at least two plates (106, 106', 108, 108'), each plate having a row of openings (120) and a number of rod shaped heat sources being arranged in a row, wherein each heat source extends via at least two openings (120) of different plates of said stack (106, 106', 108, 108').

Description

Heated Crude Oil Pipeline

The present application claims priority of PCT/EP2014/077809 filed on 15 December 2014, the specification of which is hereby incorporated by reference in their entirety for all purposes. Field of the invention

This invention relates to a system and method for heating goods being transported in a pipeline segment. Specifically, this invention refers to a system and method configured for effectively transferring and maintaining heat in a pipeline transport system. Description of the related art

Pipeline transportations are usually used in industries that require transportation of goods (typically fluids) from one location to another. Industrial applications that uses pipeline transportation systems includes crude oil and natural gas extraction, oil extraction, food preparation such as milk pasteurisation, beer brew- ing, alcohol distillation, making of candies and confectionaries.

Pipeline transportation may be used for applications that are confined to a short distance within an indoor environment such as a factory of facility for confectionary preparation, or over a long distance in an outdoor environment, from several feet between two districts to several miles for instance between coun- tries, for crude oil extraction pipeline.

(A) USE IN CRUDE OIL EXTRACTION

Speed of the fluid travelling along a pipeline depends on the temperature of the fluid. For example, when transporting crude oil in a pipeline transport system, the higher the fluid temperature, the faster is the speed of the fluid flowing along the pipeline. As such, viscosity of the fluid being transported is dependent on the fluid temperature. A high fluid temperature lowers the fluid's viscosity which results in faster flow velocity and less energy required to pump the crude oil. Besides, the need for an efficient method for transferring heat and maintaining a high fluid temperature during crude oil extraction is crucial in cold weather conditions. Existing problems caused by low temperature, high viscosity crude oil during extraction include:

(1) increased energy consumption to pump crude oil, which may lead to installation of additional pumps to increase flow of crude oil from underground; (2) blockage of pipelines;

(3) leakage of crude oil into surrounding environment due to high pressure in pipelines caused by blockage of pipelines; and

(4) ultimately cause downtime, where operations are seized, in order to fix pipeline failures. Such problems are usually associated with operational costs, low throughput and lower profits. Apart from spillage of crude oil, safety of repairing pipelines located outdoors may post a danger. In addition, the average lifespan of a crude oil pipeline setup is 10 years. Replacement is costly since crude oil pipelines can run between countries. US 20100101663 Al discloses a system and method for pipeline heating, for use in crude oil extraction. US 20100101663 Al attempts to solve some of the problems discussed above by heating the pipeline, such that the fluid being transported inside the pipeline is indirectly heated during the process. This is achieved by connecting transformers to the pipeline, to create an electrically conductive pipe. However, the apparatus of US 20100101663 Al has design limitations if used under cold weather conditions. Typical pipelines are made of steel. As such, during cold weather, more energy may be required to heat up the pipeline, in order to maintain the desired temperature. Additionally, repairing the pipeline during breakdown may be inconvenient and unsafe since pipelines for crude oil transportation can be located in secluded outdoor environment. (B) USE IN CHEMICAL INDUSTRY

Heat transfer is also widely used in the chemical industry. Chemical processes require varying temperatures at different stages. Generally industrial chemical processes require a lot of heating and/or cooling at a specific temperature at different stages of the process. Typical manufacturing process for chemical and petroleum products requires extremely high energy consumption, for heating, cooling, vaporizing, re-boiling, condensing, etc, which has negative impact on the environment.

EP 1251 951 Bl discloses a chemical reactor with a heat exchanger for temperature control that is capable of indirectly controlling temperature within the reac- tor, by using a printed circuit heat exchanger (PCHE). However, PCHE are relatively expensive, and blockages can easily occur due to very fine channels within the structure of a PCHE. When blockage occurs, chemical cleaning is required. Galvanic compatibility with pipeline material may also be challenging. Use of PCHE in the chemical industry may be impractical to implement in certain chemi- cal processes.

(C) USE IN FOOD PREPARATION

An alternative use of heat transfer is during industrial food preparation, for instance, chocolates. Typically, molten chocolate are high in fat content (cocoa butter). Problems arise when the temperature of the molten chocolate starts to cool down when travelling along the pipeline transport system and cocoa butter crystallizes. This crystallization produces specks of white spots in the end pro- duct, that looks like mould. As such, there is a need to maintain low fluid temperature to avoid crystallization of fats, to reduce product waste.

Another example is the extraction of edible plant-based oil, where heat transfer is used to maintain a low fluid temperature so as to cool down and liquefy oil vapours during solvent extraction process. A method for maintaining low temperature for edible oil extraction as disclosed in US 5,408,924 teaches the use of heat transfer in a solvent extraction process for producing edible vegetable oil using low temperature, low energy consumption method. However, the teachings of US 5,408,924 has limited function, namely, the pipeline transportation is not applicable for high temperature, low energy consumption, e.g. in a crude oil extraction application.

(D) USE IN A MARINE VESSEL OR OFFSHORE

Ships, cruises and oil tankers usually have an engine room to power up the marine vessel. The engine room requires pumping, filtering, purifying and heating of fluids, which can be performed using pipeline systems. Typically, a vessel will have several pipelines, each performing a different function. Main applications includes conveying fuel oil to the main propulsion engine and power generators, supplying lubricating oil to rotary machines within vessel, and cooling the engine. As such, heating demand is very high to ensure efficiency of the vessel. Apart from high energy consumption, failure of marine vessel pipelines are also associated with oil and chemical spillage, which will pollute oceans and endanger marine life.

Pipelines are also installed for offshore applications, such as transportation of natural oil and gas under seabed. US 6,049,657 discloses a method of heating an offshore pipeline by applying alternating current directly to the pipeline. An insulating coating is used on the pipeline to thermally heat up the pipeline. However, it is known to the person skilled in the art that pipelines are subject to daily us- age to maximise throughput. As such, given that the lifespan of a pipeline system is approximately ten years, this method does not solve the problem of cost efficiency and reducing operational costs. Further installations of offshore pipelines are time consuming and affect downtime. Summary of the invention

The objective of this invention is to provide a system and method for heating a fluid flowing through a pipeline transport system that addresses the problems discussed above, in particular a system and method that is low in operational costs, achieve zero downtime, with flexible design that improves safety during repair work, environmental-friendly (less energy consumption, zero pollutants), and at the same time, provide temperature control flexibility for different thermal transfer applications, to serve different industries.

A solution of the problem is provided by a heat transfer assembly for a pipeline segment as described in claim 1 and by a pipeline segment with the heat transfer assembly. The dependent claims relate to further improvements of the invention.

The heat transfer assembly enables efficiently heating a fluid flowing through a pipeline segment. The heat transfer assembly comprises at least a first stack of at least two plates. Preferably, the plates are spaced from each other, for example equally or evenly spaced. Each plate has a row of openings. The openings may be evenly spaced from each other. A number of rod shaped heat sources is arranged in a row, wherein each heat source extends via at least two openings of different plates of said stack. For example the stack may comprise three or more plates and each heat sources extends through aligned openings in the respective num- ber of plates. In a preferred example, the openings are oval. Preferably, the rod shaped heat sources are thermally connected to the plates of the stack, at least to said first and second plates. Thereby, the heat transfer surface and thus the heat transfer is enhanced. In addition, the heat sources and the plates may be mechanically connected to each other to thereby provide a self- supporting heat transfer assembly.

Preferably, the plates have a good thermal conductivity; for example the thermal conductivity κ of the material may be bigger equal to 0,25Wcm ^K¹ (0,25 Wcm ^-1K^" ¹≤ K). For example iron has a thermal conductivity of K_FE of about 0,8 Wcm ^_1K ¹ and the thermal conductivity of aluminum κ_Αι is about 2,38 Wcm ^_1K ¹ (Source: Ashcroft/Mermin, Solid State Physics, Table 1.6). In particular for heating liquid foodstuffs, like milk, beer or water stainless steel is preferred, but has a lower thermal conductivity (typically 0.35 to 0.45 Wcm ^_1K ^_1 ) than other metals like aluminum or copper. To resolve this problem, the plates may comprise a core of a first metal having a higher thermal conductivity than stainless steel being en- closed by a layer of stainless steel.

The plates of the stack may each have a longitudinal axis and which is at least essentially (±5°) parallel to the longitudinal axis of the other plates of said stack. Thereby, the flow resistance of the heat transfer assembly is kept low.

The rod shaped heat sources may as well have longitudinal axes which are pref- erably each parallel to the longitudinal axes of the other heat sources of said stack, to thereby provide a homogenous heat transfer and maintain a low flow resistance.

Particularly preferred, the heat sources' longitudinal axes are inclined to the plates' longitudinal axes by 15° to 35°, preferably by 20° to 30°, or even better by 25° (±2.5°). Thereby, the heat transfer is further enhanced and the fluid is efficiently mixed to provide a homogenous fluid temperature. For example each heat source may comprises (or essentially consist) of a heat pipe and a heater cartridge, the latter being inserted in said heat pipe. The heater cartridge may be an electrically powered heater cartridge.

A heated pipeline segment can be obtained easily by simply inserting at least one heat transfer assembly into a conduit being enclosed by a tubular shell. As usual the tubular shell has an inlet and an outlet and is configured for guiding a fluid flow from the inlet along a longitudinal axis of the tubular shell to the outlet. Thereby the fluid contacts the heat transfer assembly, in particular said stacked plates and the heat sources connecting them. Heat provided by the heat sources may be transferred directly from the heat sources to the fluid passing through the heat transfer assembly and indirectly via the plates from the heat sources to the fluid.

Preferably, the plates' longitudinal axes are at least essentially parallel (±5°) to the pipeline segment's longitudinal axis to keep the flow resistance low. Particularly preferred, at least two heat transfer systems (e.g. three, four or five or more heat transfer systems) are positioned inside the tubular shell. The plates' longitudinal axes of the different stacks are at least essentially parallel (±5°) to each other to keep the flow resistance low. The heat transfer systems may be aligned and may be positioned one besides of the other. The heat trans- fer systems provide a heat transfer assembly.

Preferably, the longitudinal axes of the heat sources of a first of said at least two heat transfer systems are aligned in a first direction and the longitudinal axes of the heat sources of the a second of said at least two heat transfer systems are aligned in a second direction to thereby enhance mixing of the fluid. The plates' longitudinal edges of neighbored heat transfer systems may overlap, i.e. the plates of a first heat transfer system may engage into the spaces provided between the plates of a neighbored heat transfer system to thereby enhance the heat source density and thus the heat transfer in the pipeline segment. If not enhancing the heat source density, i.e. the number of rows of heat sources, said overlapping provides an augmented heat exchange surface and thus a better heat transfer. However, the flow resistance is increased as well. In an embodiment with reduced flow resistance, the opposed longitudinal edges of neighbored heat transfer systems do not overlap. For example the opposed edges of two adjacent heat transfer systems (i.e. of the respective plates) may each define a plane. The corresponding planes may be parallel and spaced from each other, wherein the distance between said planes defines the distance between the two adjacent heat transfer systems. In a particularly preferred embodiment the distance is zero (or at least almost zero), i.e. the two planes are identical. Said embodiment showed a particular efficient tradeoff between flow resistance and heat transfer. Preferably, the plates of at least one of said heat transfer systems are at least approximately parallel (±5°) and preferably evenly spaced (±10%). In case of two adjacent heat transfer systems with at least approximately parallel (±5°) and preferably evenly spaced (±10%) plates, the plates of a first of said two adjacent heat transfer systems may be parallel to the plates of the second of said two ad- jacent heat transfer systems. (This can be extended of course to any number of heat transfer systems.) Further, the plates of the first heat transfer system are preferably not aligned with the plates of the second heat transfer system. For example, there may be an offset perpendicular to the planes' surfaces, which is preferably about 0.5 (±10%) the distance between two neighbored plates of the same heat transfer system.

A guide plate may be positioned to the left and/or to the right of at least one heat transfer system. Left and right refer to the longitudinal edges of the plates which are preferably aligned to the intended flow direction. The guide plates ensure that the entire flow passes through the spaces provided between the plates. In addition a guide plate may enhance the structural stiffness, if attached to at least two plates of a heat transfer system. Preferably guide plates are positioned only at both sides of the heat transfer assembly. The heat sources may preferably protrude through openings in the tubular shell and may have connectors for connecting the heat sources to an energy supply. Said connectors are preferably outside the conduit.

The holes may have an e.g. cylindrical inner surface and the (e.g. cylinder) axis of each hole may be inclined with respect to the respect to the respective plate's normal. The angle a may be for example between 15° to 35° (15°≤ a≤35°), preferably between 20° to 30° (20°≤ a≤30°), or even better about 25° (±2.5°). The axes of a row of openings are preferably parallel and preferably each axis coincides with the axis being defined by an opening in another plate of said stack. The inner surface of the openings should be adapted to the cross section of the heat sources extending through the openings. Thus, the cylinder surface named above is only a preferred example.

A control box may be connected via wires with said connectors to thereby provide the heat sources with electricity and to control their proper functioning.

A number of heat transfer systems may be mounted to a support, to ease as- sembly and maintenance. Free ends of the heat sources may extend through said support.

The tubular shell may have a longitudinal opening for inserting the heat transfer systems being mounted on the support into the conduit. The opening may be thereby closed by said support, which so to speak extends the tubular shell. The opening and the support may thus be complementary. One may thus refer to the support as a preferably detachable shell. The free ends of the heat sources are thus outside the pipeline's fluid duct and may thus be connected to at least one cable easily.

Said detachable shell may have a support plate to which the heat transfer systems are attached as explained above. For example the heat sources may extend through said support. Optional guide plates may be attached to the support plate as well. The support may be a plate, preferably a curved plate, e.g. segment of a hollow cylinder, completing the duct. All these measures enhance the structural stiffness and the fluid flow through the pipeline.

At least one, preferably at least two preferably parallel webs are attached to the outside of the support plate (with respect to the pipeline duct), thereby enhancing the structural stiffness of the support and thus the pipeline. Further, the space between the webs provides a cable duct for cables connecting the heat sources with an electrical energy source and/or for cables connecting probes (at least one) with control means. All cables may be provided to a control box. Only to avoid ambiguities, the term parallel is clarified: In a two dimensional system two lines are parallel in case they do not intersect, but here the system is three dimensional. Thus, two straights are parallel in case they have the same orientation. This is equivalent to the condition that the distance of any point of a first straight to a second straight is a constant, wherein the distance is the length of the shortest line segment connecting said point of the first straight with the second straight.

Description of Drawings

In the following the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with refer- ence to the drawings.

FIG. 1A shows a top view of the preferred embodiment. FIG. IB shows a cross-section view of the preferred embodiment.

FIG. 1C shows the magnified view of the heat pipes used in the present invention, inclining at an angle.

FIG. ID shows a magnified view of section A - A of the pipeline system view from the side perspective.

FIG. IE shows a slightly different pipeline in a section like Fig. ID.

FIG. 2A - 2B show a part of the top view and cross-section view of the preferred embodiments of the present invention in a partially enclosed pipeline transport system. FIG. 3A illustrates a first layer of the heat conductive plate and FIG. 3B illustrates a second layer of the heat conductive plate, respectively.

FIG. 4 shows a tabulated calculation of the heat exchange area applicable to the subject invention.

FIG. 1A shows the top view of a pipeline system 100. A control box 102 (see Fig. 2a, 2b) may be mounted on an outer shell 104 of the pipeline system 100. The control box may supply energy to power up the pipeline system 100. Alternatively the control box may be positioned in a control room or a power supply room. The pipeline system is configured for maintaining the temperature of the fluid being transported by the pipeline system. Fluids may enter an inlet end E of the pipeline system 100 and flows out via an outlet end E' of the pipeline system 100. Depending on application, each pipeline system 100 may be connected to another identical pipeline system 100, thus creating several segments of a larger pipeline transport system that runs across several feet or miles. Alternatively, non-heated pipeline segments may be con- nected to the inlet E and/or the outlet E'. For clarity, the term "system" referred to herein, shall be understood to encompass an individual pipeline segment 100, as well as segments 100 configured to construct a larger or full pipeline transport system.

A plate or a plank 106, 106', 108, 108'with heat exchange properties is config- ured to heat up fluid passing through top and bottom of the plate. Heat exchange properties are to be understood as reasonable thermal conductivity. The plates or planks 106, 106', 108 108' may be e.g. of a metal or another material or compound having a similar thermal conductivity. The choice of the material is a tradeoff between price, durability, process ability and thermal conductivity. Multiple heat conductive plates 106, 106', 108, 108' may be piled one on top of the other, to form multiple stacks of heat conductive plates 106, 108, as shown in FIG. 1A. Each stack may comprise at least two parallel

plates 106, 106', 108, 108' being spaced from each other with a distance d.

Preferably, each plate 106, 106', 108, 108' has a plurality of rows (at least one row) of e.g. elliptical openings 120, gaps, holes or apertures aligned along the length, i.e. parallel to the longitudinal direction of the pipeline system 100 , as shown in detail in Fig. 3B. The term "row" used herein, refers to a series of objects being positioned along a virtual or real line and preferably evenly spaced from each other. As can be seen in Fig. IB, heat sources may protrude or extend through the openings 120 and are thermally connected to the respective plates 106, 106',108, 108'. The plates 106, 106', 108, 108' are thus so to speak a heat sink connected to said heat source. The heat source may be an elongate body, e.g. a heat pipe 112, 114 and/or an electrical heater cartridge 118, or as explained below in more detail a heat pipe 112, 114 with an integrated heater cartridge 118. Beyond the heat sources 112, 114 may as well be mechanically connected to the plates to thereby provide a self-supporting heat transfer system. The mechanical connection may be provided in almost any known manner adapted to the intended application, e.g. welding, soldering, gluing, press fitting etc.

FIG. IB shows a plurality of heat pipes 112, 114 (as example for said heat sources) aligned in rows. These heat pipes 112, 114 may for example comprise an electrical heater cartridge 118 as suggested in US 09/928,883 filed on 13 August 2001 and/or PCT/EP2012/066909 filed on 30 August 2012, which are incorporated herein as if fully disclosed. The housing of the heat source may have a fin surface, a smooth surface, or a combination of both.

FIG. 1C illustrates heat pipes 112, 114 inclining at an angle, between 20.0^° to 30.0^°, more preferably about 25.0^°, relative to the longitudinal axis 101 of the pipeline segment 100. Each heat pipe 112, 114 has a first end and a second end, with at least one electrical heat cartridge 118 attached to one end of the heat pipe. A first heat pipe 112, 114 may be placed parallel to a second heat pipe 112, 114, e.g. at a distance approximately 20mm apart. The aforesaid ar- rangement is repeated using a plurality of heat pipes 112, 114, thereby forming a row of heat pipes 112, 114. Each row of heat pipes 112, 114 may be inserted into a detachable and/or isolating shell 110 of the pipeline system 100, at said inclining angle. Multiple rows of slots, holes or apertures larger than the circumference of the plurality of heat pipes 112, 114 may be supplied by the detachable and/or isolating shell 110, configured to engage and disengage each of the heat pipes 112, 114 from the detachable or isolating shell 110. The detachable and/or isolating shell 110 may provide a cable duct for power lines connected to the heat sources. Preferably the heat sources comprise a temperature probe which may be connected via a cable with the control box 102 as explained with respect to Fig. 2A and Fig. 2B.

FIG. ID shows a magnified view of section A - A' (as indicated in Fig. 1A) of the heat exchange assembly within pipeline system 100, from a side perspective. Preferably, there is (for example) at least approximately 20mm distance between each end of the heat pipe 112, 114 and the inner wall 103 of pipeline system 100.

Each heat pipe 112, 114 is inserted through the elliptical openings 120 of the stacks of heat conductive plates 106, 106', 108, 108' to form heat exchange systems within the pipeline system. A first heat conductive

plate 106, 106', 108, 108' is piled on top of a second heat conductive

plate 106, 106', 108, 108', at a distance d of for example approximately 20mm. Each of the elliptical openings 120 on the first heat conductive

plate 106, 106', 108, 108' is parallel to each of the elliptical openings 120 on the second heat conductive plate 106, 106', 108, 108'. Parallel refers here to the openings axis. In case the opening is drilled, the bore axis defines the axis. The aforesaid arrangement is repeated using a plurality of heat conductive plates 106, 106', 108, 108', thereby forming a stack of heat conducting plates 106, 106', 108, 108'. A heat transfer assembly is configured by inserting the rows of heat pipes 112, 114 through the elliptical openings 120 of the stack of heat conductive plates 106, 106', 108, 108', forming a heat exchange assembly.

Preferably, there is a guide plate 111 in the pipeline on each side of heat ex- change assembly, as shown in FIG. ID or for a slightly different embodiment in Fig. IE. The guide plates 111 guide the flow of the fluids traveling within the pipeline transport system 100. The guide plates 111 also function to cordon off the sides of the pipeline 100, to ensure efficient heating within a specific heat exchange area. In a preferred embodiment, the outer rows of heat pipes 112, 114 nearest to the inner walls 103 of the pipeline 100 are extending in a first direction, and the inner rows of heat pipes 112, 114 are configured to extend in a second direction. In an alternative embodiment, alternating rows of heat pipes 112, 114 are facing in a different direction. The heat pipes 112, 114 may have a smooth surface, a fin surface or combination of both, and the entire heat exchange assembly is configured inside the pipeline system 100, to optimize heat transfer, without influ- ence from external environment.

Each heat pipe 112, 114 may be spaced approximately 20 mm (as example) apart from the next heat pipe 112, 114. In this example, the setup of the heat exchange assembly divides the fluids into 20mm by 20mm of matrixes, surrounding the matrixes with heat pipes 112, 114 and heat conductive

plates 106, 106', 108, 108'. Heat exchange process is optimized as such. By choosing a different distance between the heat pipes 112, 114, the size of the matrixes can be adjusted. The configuration of the heat pipes optimizes flow velocity, thereby creating vortex at each intersection. The entire heat assembly configuration can be extended depending on requirements of pipeline specifica- tion. Ideally, the heat assembly has a heat transfer area of up to 80 - 90 square meters, which is efficiently heated by the heat pipes 112, 114 with its heater cartridges 118.

In the examples shown of Fig. 1A to Fig. ID and Fig. IE, the plates of the heat transfer systems are at least approximately parallel (±5°) with respect to the plates of the same and the other heat transfer systems. Beyond, the plates are preferably evenly spaced (±10%) perpendicular to the respective plates' extension. In the example of Fig. 1A to Fig. ID, the plates' longitudinal edges of neighbored, i.e. adjacent heat transfer systems overlap. The plates 106, 106' of a first heat transfer system may engage into the spaces provided between the plates 108, 108' of a neighbored heat transfer system. This enables to enhance the heat source density and thus the heat transfer in the pipeline segment. In addition the said overlapping provides an augmented heat exchange surface and thus a better heat transfer. The example shown in Fig. ID differs from the exam- pie shown in Fig. 1A- Fig. IE only in that the opposed longitudinal edges of neighbored heat transfer systems do not overlap. In particular the opposed edges of two adjacent heat transfer systems each define a plane. The corresponding planes are for example essentially parallel (±5°). The distance between said planes may be small (e.g. 0-5mm). Beyond the description of Fig. 1A to Fig. ID applies as well to Fig. IE.

As can be seen best in Fig. IE (but as realized as well in Fig. 1A), the heat transfer systems may be mounted one besides of the other to a support 115, thereby providing a heat exchange assembly. Free ends of the heat sources 112,114 may extend through said support. The tubular shell may provide a longitudinal opening via which the heat transfer systems can be inserted and which is closed by the support 115. As can be seen, the support preferably extends pipeline's shell, i.e. the inner wall 103. For maintenance the support can be released and the heat transfer systems may be removed from the pipeline. One may thus refer to the support as a preferably detachable shell. The free ends of the heat sources are outside the pipeline's fluid duct and may thus be connected to at least one cable (without reference numeral).

As shown, the support 115 may be a plate, preferably a curved plate, e.g. segment of a hollow cylinder, completing the inner wall 103. Webs 106 are attached to the support 115 to the left and to the right of the free ends of the heat sources 112, 114 extending through the support plate. The webs 116 enhance the structural stiffness of the support 115 and thus of the pipeline segment 100. Further, the space between the webs 106 provides a cable duct for said cables connecting e.g. heat sources with an electrical energy source and/or for cables connecting probes (at least one) with control means. All or some cables may be provided to a control box 102. FIG. 2A - 2B show a part of the top and cross section view of a preferred embodiment enclosed in a pipeline transport system 100. The pipeline transport system 100 has a tube design with the inlet end E and the outlet end E' flanged outwards. Part of the circumference of the tubular pipeline transport system may have an open surface. A detachable or isolating shell 110 may cover said opening, thereby creating a duct, channel or conduit within the pipeline system 100. The detachable or isolating shell 110 may comprise rows of wire slots and/or heat pipe receiving units. Each of the second end of the heat pipes may be configured to engage and disengage with the wire slots or heat pipe receiving units. In operation, the control box 102 may receive input from an operator to supply power to the pipeline transport system 100. The control box 102 is able to receive feedback from the wire slots, thus allowing the operator to monitor performance of each heat pipe 112, 114, and thereby enabling to replace electrical heater cartridges 118 of individual heat pipes 112, 114, in case of failure. Since each electrical heater cartridge 118 is configured to engage and disengage with each wire slots, repair and cleaning work can be safely and easily carried out by shutting down the power of the pipeline system 100 and replacing possibly defective electrical heat cartridges 118 individually. Flexibility of replacing individual electrical heat cartridge 118 also ensures downtime is minimal. FIG. 3A - 3C each shows a heat conductive plate 106, which may be used e.g. in one of the preferred embodiments. The thickness may be selected according to the needs, e.g. between 1.5mm to 2.5mm. The dimension of each conductive plate may be e.g. 183.5mm by 650mm. It will be known to the person skilled in the art that other dimensions are applicable, based on thermal conductivity the- ory. The heat conductive plates 106', 108 and 108' may be identical or similar to the heat conductive plate 106 as shown, to thereby ease manufacturing. Specifically, FIG. 3A - 3B illustrate a first layer of heat conductive plate 106 and a second layer of heat conductive plate 106, respectively. The openings 120 for receiv- ing an end of the heat pipes 112, 114 are illustrated by the four rows of elliptical openings 120.

Due to the vortices created by the liquid flow surrounding the heat pipes, fluid being transported is constantly circulating between the heat transfer assembly and this fluid motion enables parts of the fluid having a higher temperature to interact with other parts of the fluid having a lower temperature. The fluid is thus efficiently and steadily mixed to thereby provide a homogeneous temperature distribution in the pipeline 100. Beyond, this interaction of higher and lower temperature fluid parts of the flow amongst the layers of heat conductive plates and quantum heat pipes maximises heat exchange and allows uniform heat transfer, thereby maintaining fluid temperature at a desired level. This provides functional temperature control, allowing the subject invention to be applied to different thermal transfer applications that requires both high temperature and low temperature. No pollutants are released into the environment. This is espe- daily applicable to crude oil extraction, where the ability to maintain high temperature, low viscosity of the crude oil throughout the application is crucial to prevent blockage and possibility of leakage of crude oil into the surrounding environment.

It will however be understood by a person skilled in the art that the present in- vention is not limited to specific forms, arrangements or structures of the embodiments described above. It will be apparent to a person skilled in the art in view of this disclosure that numerous changes and/or modifications can be made. List of reference numerals

100 pipeline / pipeline system

101 longitudinal axis

102 control box

103 inner wall

104 outer shell

106 plate / plank

106' plate / plank

108 plate / plank

108' plate / plank

109 longitudinal axis of a plank

110 detachable/isolating shell

111 guide plate

112 heat source / heat pipe

114 heat source / heat pipe

115 support

116 web

120 opening / elliptical opening

E inlet of a pipeline segment 100 E' outlet of a pipeline segment 100

Claims

1. A heat transfer system for a pipeline segment (100) for heating a fluid flowing via said pipeline segment,

characterized in that

the heat transfer system comprises at least a first stack of at least two plates (106, 106', 108, 108'), each plate (106, 106', 108, 108') having a row of openings (120) and a number of rod shaped heat sources (112, 114) being arranged in a row, wherein each heat source extends via at least two openings (120) of different plates (106, 106', 108, 108') of said stack.

2. The heat transfer system of claim 1

characterized in that

the rod shaped heat sources (112, 114) are thermally connected to at least said first and second plates (106, 106', 108, 108').

3. The heat transfer system of claim 1 or 2

characterized in that

the rod shaped heat sources (112, 114) have a longitudinal axis and the plates(106, 106', 108, 108') each have a longitudinal axis and in that the plate's longitudinal axes are parallel (±5°) to each other and/or in that the heat source's longitudinal axes are parallel (±5°) to each other.

4. The heat transfer system of claim 3

characterized in that

the heat sources longitudinal axes are inclined to the plate's longitudinal axes by 15° to 35°.

5. The heat transfer system of one of claims 1 to 4

characterized in that each heat source (112, 114) comprises a heat pipe (112,114) and a heater cartridge (118) being inserted in said heat pipe (112, 114)

The heat transfer system of one of claims 1 to 5

characterized in that

the openings (120) in the plates (106, 106', 108, 108') are oval.

A pipeline segment (100) with a conduit being enclosed by a tubular shell (110) with an inlet (E), an outlet (Ε') for guiding a fluid flow from the inlet (E) along a longitudinal axis (101) of the tubular shell (110) to the outlet (Ε'),

characterized in that

at least one heat transfer system of one of claims 1 to 6 is positioned inside the tubular shell (110).

The pipeline segment (100) of claim 7,

characterized in that

the plate's longitudinal axes are at least essentially parallel (±5°) to the pipeline segment's longitudinal axis (101).

The pipeline segment (100) of claim 7 or 8,

characterized in that

at least two heat transfer systems are positioned inside the tubular shell (110), wherein the plate's longitudinal axes are at least essentially parallel (±5°) to each other .

The pipeline segment (100) of claim 9

characterized in that

the longitudinal axes of the heat sources of a first of said at least two heat transfer systems are aligned in a first direction and the longitudinal axes of the heat sources of the a second of said at least two heat transfer systems are aligned in a second direction.

11. The pipeline segment (100) of claim 9 or 10

characterized in that

the plates (106, 106', 108, 108') longitudinal edges of neighbored heat transfer system overlap.

12. The pipeline segment (100) of one of claims 7 to 11,

characterized in that

at least one guide plate (111) is positioned to the left and/or to the right with respect of at least one heat transfer system or besides of a heat transfer system formed by at least two heat transfer systems.

13. The pipeline segment (100) of one of claims 7 to 12,

characterized in that

the heat sources (112, 114) protrude through openings in the tubu- lar shell (100) and have connectors for connecting the heat sources to an energy supply and in that connectors are arranged outside the tubular shell (110).

14. The pipeline segment (100) of claim 13,

characterized in that

a control box 102 is connected via wires with said connectors.