RO128317A2 - Heat exchanger - Google Patents

Abstract

The invention relates to a heat exchanger for the transfer of heat to a working liquid, such as water, intended to convert at least partially the liquid water into saturated or superheated steam. According to the invention, the heat exchanger comprises some left and right walls (), a top portion () and a pair of vertical steam/water separators () particularly suited to handle large transient swings in heat input to the heat exchanger () which may, in turn, cause large variations in water levels within the steam/water separators (), the side walls () comprising panels of tubes having a welded membrane between adjacent tubes, and, when the heat exchanger () is used to provide merely saturated steam, the side walls () and the roof portion () comprise evaporative or boiler heating surface while, when the heat exchanger () is used to provide superheated steam, some of the heating surface will have to be evaporative surface and other portions will have to be superheater surface, the side walls () being evaporative or boiler surface, which may be provided with inlet headers () and outlet headers (), the steam-water mixture generated in tubes forming the side walls () being collected in the outlet headers () which also serve as a mixing point to even out temperature unbalances which may exist in the steam-water mixture, some stubs () on the outlet headers () being interconnected by the risers to some stubs () on the upper portions of each of the vertical steam/water separators ().

Description

HEAT EXCHANGER

FIELD AND BACKGROUND OF THE INVENTION The present invention relates generally to the field of heat exchangers and, in particular, to a heat exchanger with an integral support structure and a structural framework for supporting it.

The present invention utilizes US Patent No. 6,336,429 to Wiener et al. a., the text of which is included here as a reference, as set out here.

To the extent that explanations regarding certain terminologies or principles in the field of heat exchangers, boilers and / or steam generators may be necessary to understand the present invention, the reader may refer to the chapter "Steam / generation and use", 40th edition, Stultz and Kitto, Eds., Copyright © 1992, The Babcock & Wilcox Company, and "Steam / Generation and Use", 41st edition, Kitto and Stultz, Eds., Copyright © 2005, Babcock & Wilcox Company, the texts of which are incorporated herein by reference, as set forth herein.

SUMMARY OF THE INVENTION One of the aspects of the present invention relates to a heat exchanger for the transfer of heat energy into a working liquid, such as water. The heat exchanger is used to convert at least part of the liquid phase water into saturated or overheated steam.

The vertical steam / water separation devices presented in the aforementioned US Patent No. 6,336,429 to Wiener et al. a., are used to separate the steam from the steam-water mixture. A pair of such vertical steam / water separators, structurally interconnected and arranged as described herein, provides a complete support structure for the heat exchanger.

The heat exchanger according to the present invention is advantageously composed of a set of heat transfer surfaces and pipes for the transport of fluids, specially arranged to transfer the desired amount of thermal energy to water. The heat transfer surfaces are advantageously made from pipes arranged in panels and are provided with inlet and outlet connections as needed. As is known to those skilled in the art, heat transfer surfaces carrying steam-water mixtures are generally referred to as evaporation or boiling surfaces; steam-transfer heat transfer surfaces are commonly referred to generally as overheating (or reheating, depending on the configuration of the associated steam turbine). Regardless of the type of heating surface, (Κ-2 0 1 0 - 0 0 ^ 07'1 4 -01- 2009 the dimensions of the pipes, the material, the diameter, the wall thickness, their number and arrangement are based on the operating temperature and pressure, in accordance with applicable boiler design codes, such as the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section I, (Code of Boilers and Pressure Vessels of the American Society of Mechanical Engineers (ASME), or other equivalent codes required by law The mandatory characteristics of heat transfer, pressure loss, circulation ratios, on-site absorption rates, mass flow rates of working fluid inside pipes, etc. are also important parameters to be taken depending on the geographic location where the heat exchanger is to be installed, the applicable seismic loads and the Design are also considered.

The heat exchanger is supported at the bottom of a base which is part of an assembly of interconnected rigid elements surrounding the heat exchanger and forms a structural support framework which, together with the abovementioned integral support structure, not only does it provide structural support and rigidity for the heat exchanger, but it is also a means by which the heat exchanger can be taken and lifted for placement in a desired location, if the heat exchanger is used as a solar thermal energy receiver, The structural support frame allows the entire assembly of the heat exchanger and frame to be assembled to the ground and then lifted and placed on a tower during installation. The structural support frame remains with the heat exchanger, thus facilitating (if necessary) the removal of the heat exchanger from the tower should this be desired.

According to the present invention, there is provided a heat exchanger comprising a set of heat transfer surfaces and a pair of vertical steam / water separators, structurally interconnected between them and providing a complete support structure for at least a portion of the heat transfer surfaces of the heat exchanger. Structural interconnection includes upper and lower structural elements made of thick-walled pipes that extend between vertical steam / water separators. Each of the thick-walled pipes includes a pair of transverse interior partitions to form a central part in which a collector is defined. The fully supported part of the heat transfer surfaces extends between the collectors of the upper and lower structural elements and is connected fluidly to them.

Each of the vertical steam / water separators includes four coplanar pedestal feet positioned at the lower end of the steam / water separator, and disposed at equal distances to the outer edge of the steam / water separator.

The heat exchanger includes a structural support frame in the form of a rectangular parallelipiped having an upper side, a lower side and the opposite longitudinal sides surrounding the heat exchanger to support it at the bottom.

- 1 4 -Or ZJOSl The lower part of the supporting structural frame is made up of four lateral and longitudinal bars spaced parallel to the horizontal extension and which intersect between them center to form a grid-like structure that includes a grid network. obliquely arranged elements of the network positioned between the longitudinal and lateral intersecting beams.

Two pairs of lateral tie rods intersect the two inner beams between the four longitudinal beams at the bottom of the structural support frame, to form the support bases for vertical steam / water separators. The base legs of the steam / water separator are securely fastened to the respective support base.

Each of the opposite longitudinal sides of the supporting structural frame has two pairs of parallel spaced vertical beams at the opposite ends of the structural frame and a pair of parallel spaced longitudinal beams that intersect the vertical beams and are located at the top end of each the opposite sides. A grid of oblique grid elements is positioned between each pair of vertical beams and the pair of longitudinal beams.

The top of the supporting structural frame is made up of two lateral beams that intersect the upper beam from the pair of parallel spaced beams that extend along each longitudinal side. The two side beams are located above the heat exchanger and provide a means by which the heat exchanger and the supporting structural frame can be raised to fit in a desired location.

Another aspect of the present invention relates to a combination of a heat exchanger and the structural framework used to support it. The combination comprises a set of heat transfer surfaces and a pair of vertical steam / water separators that are structurally linked to each other and offer a complete support structure for at least a portion of the heat transfer surfaces. The structural connection between the surfaces of the heat exchanger and the pair of vertical steam / water separators is composed of the upper and lower pipes with thick walls, each pipe having partitions defining a central manifold. The fully supported part of the heat transfer surfaces extends between the top and bottom pipes with thick walls and is fluidly connected to them. Each of the steam / water separators includes a plurality of pedestal feet positioned at the bottom end of the steam / water separator.

The structural frame part of the combination has an upper side, a lower side and the opposite longitudinal sides surrounding the heat exchanger to support it at the bottom. The lower part of the structural frame consists of four lateral and longitudinal beams spaced parallel to the horizontal extension and which intersect each other to form a grid-like structure and include a network of obliquely arranged elements of the network positioned between the intersecting beams. longitudinally and laterally. Two pairs of lateral tie rods arranged in parallel intersect the two inner beams between the four longitudinal beams at the bottom of the frame

CV 2 C 'D - ο O ^' o 7 - 1 4 -01- 2009 structurally, to form the support bases for the vertical steam / water separators whose support legs are securely fastened to the respective support bases. Each of the opposite longitudinal sides of the structural frame has two pairs of parallel spaced vertical beams at the opposite ends of the structural frame and a pair of parallel spaced longitudinal beams that intersect the vertical beams and are located at the top end of each of the opposite sides. A grid of oblique grid elements is positioned between each pair of vertical beams and the pair of longitudinal beams. The upper part of the structural frame consists of two lateral beams which intersect the upper beam from the pair of parallel beams mentioned. The two side beams are located above the heat exchanger and provide a means by which the heat exchanger and support frame can be lifted for placement in a desired location. These and other features of the present invention will be better understood and the advantages will be more readily appreciated from the following description, especially if read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the heat exchanger, which is presented, for reasons of clarity, without the structural support framework according to the present invention;

FIG. 2 is an exploded perspective view of the heat exchanger illustrated in Fig. 1; FIG. 3 is a perspective view of the pair of vertical steam / water separators structurally linked to each other to provide an integral support structure, in accordance with the present invention, and FIG. 4 is a perspective view of the fully supported structure of the heat exchanger in FIG. 3, together with the structural framework used to support the structure of the heat exchanger according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION In the following, reference will be made to the accompanying drawings in which the identical figures define identical or functionally similar elements in the various drawings.

Referring to Figures 1-3, a heat exchanger 10 is represented according to the present invention. The heat exchanger 10 has left and right walls 12, an upper portion 14 and a vertical steam / water separator pair 16 of the type described in US Patent No. 6,336,429 to Wiener et al. a., mentioned above. The vertical steam / water separators 16 of this type are specially adapted to withstand the large transient oscillations of the amount of heat entering (\ -2 Ο 10 - Ο Ο 7 - - Ip 1 h -01-2009 ¹ in the heat exchanger 10, which in turn can cause large variations in the water levels inside the steam / water separators 16. The side walls 12 are made of pipe panels with a membrane welded between the adjacent pipes. known to those skilled in the art and will not, therefore, be described in detail here; for further details, the reader will consult the abovementioned "Steam" texts. The roof part 14 is also composed of membrane panels welded to pipes. . while pipe wall panels are usually used in conventional industrial furnace walls and utilities to make an impervious construction. gas-tight, the provision of membranes between the pipes adjacent to this application also ensures the structural rigidity of the panels and this is why the sidewall panels 12 and the roof portion 14 have a membrane wall construction.

If the heat exchanger 10 is used to supply only saturated steam, the side walls 12 and the roof portion 14 comprise the evaporation surface or the heating surface of the boiler. If the heat exchanger 10 is used to provide superheated steam, and as will be appreciated by those skilled in the art, part of the heating surface will have to be an evaporating surface, and other portions will have to be a superheating surface. . In the embodiment of FIG. 1, the side walls 12 constitute an evaporation surface or boiler surface, and may be provided with the inlet connections 18 and the outlet connections 20. The steam mixture generated in the pipes forming the side walls 12 is collected in the outlet manifolds 20, which serve, also as a mixing point to smooth the temperature imbalances that may exist in the steam-water mix. The sockets 22 on the outlet manifolds 20 are interconnected via the ascending ducts (not shown) to the sockets 26 of the upper portions of each of the vertical steam / water separators 16. The vertical steam / water separators 16 operate in the known manner (see US Patent No. 6,336,429 to Wiener et al.), Separating the steam from the steam-water mixture. If the heat exchanger 10 is designed for the production of saturated steam, the steam outlet connections (not shown) from the upper portions of each of the separators 16 transmit the steam to its downstream location for use. If the heat exchanger 10 is designed to produce superheated steam, the steam is transmitted from the separators 16 to the additional surfaces of the superheater for heating and finally for collection and transport to its downstream location and for use. Depending on the initial temperature and pressure of the steam, as well as the desired outlet temperature of the superheated steam, the superheater could be designed as a multi-stage superheater to provide adequate rates of mass flow through the pipes of the superheater and the heater. Concepts are within the scope of the present invention. Two-pass, four-pass or additional pass-through models may be required, taking into account not only the temperatures η-2 0 1 Ο - Ο Ο j60 7 - 1 4 -01-2009 for the superheater pipes but also for the temperature of the superheat pipes. an adjacent structure, to answer the concerns regarding the differences of thermal expansion. In both cases, the water separated from the steam / water mixture is transmitted to a lower portion of each of the separators 16, mixed with feed water and transmitted to the evaporation surface at to start the process from the beginning. In order to facilitate the circulation of water and the mixture of water-steam through the heat exchanger 10, circulation pumps 28 may be advantageously provided at the bottom of each of the separators 16, for pumping water back to the surface of evaporation through feeds ( are not represented).

Referring to FIG. 2 is an exploded perspective view of the heat exchanger illustrated in FIG. 1. This view better illustrates the relationship between the side walls 12 and the integral support structure, generally positioned 30, composed of the pair of vertical steam / water separators 16, structurally interconnected with each other through the upper and lower structural elements 32.

Referring to FIG. 3, a perspective view of the pair of vertical steam / water separators 16 structurally interconnected according to the present invention is provided, which provides the integral support structure 30 for the heat exchanger 10. The upper and lower structural elements 32 are advantageously formed. , from pipes with thick walls, rather than a construction of normal I profiles or with wide soles, for reasons that will become obvious. One of the ends of each element 32 is connected to one of the vertical steam / water separators, such as by welding. The structural elements 32 do not, by themselves, produce any direct fluid interconnection between the separators 16. The thick-walled pipe constituting each of the structural elements 32 is provided with interior partitions 34, forming a central part comprising a manifold 36 which meets a fluid collection / transport function, in addition to providing an integral support structure for the heat exchanger 10, the collectors 36 which are part of the upper and lower structural elements 32 are connected together by a heating surface assembly 38 which extends between the upper and lower manifolds 36 and is fluidly connected thereto. Typically, the heating surface 38 is an upstream flow evaporation surface composed of pipes. Pipe bushings 40 constitute the connections for the ascending pipes (not shown), which transports the steam mixer to the pipe bushings 26 to the separators 16, as described above.

It is mentioned that the heating surface 38 extends between the collectors 36 of the upper and lower structural elements 32, while leaving a gap or space 42 between the distal edges of the heating surface 38 and the outer wall of the steam / water separators.

16. The side walls 12 extend into this space 42, with the distal edges of the heating surface 38 extended adjacent and located in close proximity to the inner portions of the side walls 12. With

(Κ2 Ο 1 Ο - ο Ο ίο 7 - 1 4 -01- 2009 however, to allow differential thermal expansion, the heating surface 38 is not rigidly connected to the side walls 12. The side walls 12 would be supported at the bottom on a base, in a manner similar to the description below with respect to the integral support structure 30. The side walls 12 may also be provided with supporting posts, which are not represented, and which are well known to those skilled in the art as providing rigidity and support for the construction of the membrane wall of pipes.

Referring to FIG. 4 is a perspective view of a part of the heat exchanger 10 according to the present invention, similar to that illustrated in FIG. 1, together with a structural frame 50 which supports the heat exchanger 10. For clarity, only the integral support structure composed of 30 pairs of vertical steam / water separators 16, structurally linked by means of the upper and lower structural elements 32, is represented. .

The three-dimensional structural frame 50 generally has a rectangular parallelepiped form and is defined by the upper sides 51, the upper sides 52, and the longitudinal sides 55, and includes three sets of beams in I which extend in the three reciprocal directions. perpendicular, eight longitudinal beams 58, six lateral beams 56 and eight vertical beams 54.

The lower part 52 of the structural frame 50 consists of four longitudinally spaced parallel longitudinal beams 58 and four spaced parallel lateral beams 56 which intersect each other to form a grid-like structure. A grid of oblique array members 60 is positioned between the longitudinally and laterally intersected beams 58 and 56 to structurally reinforce the grid-shaped construction forming the lower portion 52 and to strengthen or add rigidity to the structural frame 50.

The lower part 52 of the structural frame 50 includes a pair of support bases 53, each consisting of respective pairs of parallel spaced side ties 57, intersecting with the inner pair of longitudinal beams 58. Each of the steam / water separators 16 includes four pedestal feet 59 located in or near the lower part of the steam / water separator. The pedestal legs 59 extend outward from the wall of the steam / water separator, essentially, at a right angle, and are coplanar and disposed at equal distances on the outer edge of the steam / water separator 16. The pedestal feet 59 are each provided with a casing consolidation 61 and support base 53 are set.

Each of the longitudinal sides 55 of the structural frame 50 consists of two pairs of spaced parallel vertical beams 54 located at the opposite ends of the structural frame 50, as well as a pair of spaced longitudinal parallel beams 58 located at the top end of the sides 55 and which intersect in connection with the vertical beams 54. A grid of oblique array members 60 is positioned between each pair of vertical beams 54 and longitudinal beams 58, to structurally strengthen the sides 55 and to strengthen the structural frame 50.

CX-2 0 1 0 - 0 00071 4 -01- 2009 The upper part 51 of the structural frame 50 is composed of two lateral beams 56 which intersect and are connected to the upper beam of each of the pairs of longitudinal beams 58 located at the upper end of the longitudinal sides 55. In addition to the strengthening of the upper part 51 and the stiffening of the structural frame 50, the upper lateral beams 56 are generally located above the heat exchanger 10 and provide a means by which the heat exchanger 10 and the structural frame support 50 can be picked up and raised to be placed at a desired location.

Although the present invention has been described above, with reference to certain means, materials and embodiments, it is understandable that this invention may be modified in several ways once again to depart from its spirit and scope and, by that is, it is not limited to these particularities disclosed, but extends instead to all equivalents in the scope of the following claims.

Claims (30)

claims 1. A heat exchanger comprising an assembly of heat transfer surfaces and a pair of vertical steam / water separators structurally connected to each other and providing an integral support structure for at least a portion of the heat transfer surfaces of the exchanger of heat. The heat exchanger according to claim 1, wherein the structural links include the upper and lower structural elements extending between the vertical steam / water separators. The heat exchanger according to claim 2, wherein the upper and lower structural elements are formed of thick-walled pipes. The heat exchanger according to claim 3, including a pair of spaced apart walls arranged transversely in the thick wall pipe to form a central portion therein. The heat exchanger according to claim 4, wherein the central portion is a manifold. The heat exchanger according to claim 5, wherein said portion of the heat transfer surfaces extends between the collectors of the upper and lower structural elements and is fluidly linked thereto. The heat exchanger according to claim 1, including a support frame having an upper side, a lower side and opposite longitudinal sides surrounding the heat exchanger to support it at the bottom. The heat exchanger according to claim 7, wherein the structural frame is in the form of a rectangular parallelipiped. The heat exchanger according to claim 7, wherein the bottom of the structural frame is composed of horizontal beams extending laterally and longitudinally. The heat exchanger according to claim 9, wherein the side and longitudinal beams intersect with each other to form a grid-like structure. Oc2 Ο 1 Ο - Ο Ο 7 '1 4 -01- 2009 The heat exchanger according to claim 10, including a grid of grid elements positioned obliquely between the beams intersecting longitudinally and laterally. The heat exchanger according to claim 9, wherein the lower part of the structural frame includes four longitudinally spaced parallel longitudinal beams. The heat exchanger according to claim 12, including two pairs of spaced parallel lateral tie rods intersecting the two inner beams between the four longitudinal beams mentioned, to form the support bases for the steam / water separators. The heat exchanger according to claim 13, wherein each of the vertical steam / water separators includes a plurality of pedestal feet positioned at the bottom end of the separator and secured to said support bases. The heat exchanger according to claim 7, wherein each of the opposite longitudinal sides of the structural frame has two pairs of spaced parallel vertical beams at the opposite ends of the structural frame and a pair of spaced longitudinal parallel beams which intersect the vertical beams and are located at the upper end of each of the opposite sides. The heat exchanger according to claim 15, including a grid of obliquely arranged network elements positioned between each pair of vertical beams and the pair of longitudinal beams. The heat exchanger according to claim 7, wherein the upper part of the structural frame is made up of two lateral beams which intersect the upper beam of said pair of spaced parallel beams. The heat exchanger according to claim 17, wherein the two side beams are located above the heat exchanger and provide the means by which the heat exchanger and the structural frame can be raised to be placed in a desired location. 19. In combination, a heat exchanger and the structural framework for supporting it, a combination comprising an assembly of heat transfer surfaces and a pair of vertical steam / water separators structurally connected to each other and providing an integral support structure L \ - 2 Ο 1 Ο - Ο Ο Η 7 - 1 4 -01-2009 for at least ο a portion of the heat transfer surfaces, the structural frame having an upper side, a lower side and opposite longitudinal sides surrounding the heat exchanger for a-1 support from the bottom. The combination according to claim 19, wherein the structural interconnection is composed of upper and lower pipes with thick walls, each pipe having interior partitions defining a central manifold. The combination according to claim 20, wherein said portion of the heat transfer surfaces extends between the manifolds in the upper and lower pipes and is fluidly connected thereto. The combination of claim 19, wherein the lower part of the structural frame is composed of horizontal and longitudinal beams which extend horizontally and intersect with each other to form a grid-like structure. The combination according to claim 22, including a grid of obliquely arranged network elements positioned between the longitudinal and lateral beams that intersect. The combination according to claim 22, wherein the lower part of the structural frame includes four spaced parallel longitudinal beams. The combination according to claim 24, including two pairs of spaced parallel lateral tie rods intersecting the two inner beams between said four longitudinal beams, to form the support bases for the steam / water separators. The combination according to claim 25, wherein each of the vertical steam / water separators includes a plurality of pedestal feet positioned at the bottom end of the separator and secured to the respective support bases. The combination according to claim 19, wherein each of the opposite longitudinal sides of the structural frame has two pairs of spaced parallel vertical beams at the opposite ends of the structural frame and a pair of spaced longitudinal parallel beams which intersect the vertical beams and are located at the top end of each of the opposite sides. The combination according to claim 27, including a grid of obliquely arranged network elements positioned between each pair of vertical beams and the pair of longitudinal beams. The combination according to claim 19, wherein the upper part of the structural frame is composed of two lateral beams intersecting the upper beam of said pair of spaced parallel beams. The combination according to claim 29, wherein the two side beams are located above the heat exchanger and provide the means by which the heat exchanger and the structural frame can be raised to be placed in a desired location.