A double-pipe pass smoke cooler

Abstract

The utility model belongs to the technical field of industrial boiler, concretely relates to a double pipe pass's smoke cooler, specifically includes two adjacent heat exchange components, each heat exchange component includes the double pipe pass heat exchange tube bundle in heat exchanger casing and the water inlet header and water outlet header outside heat exchanger casing, is connected through the communicating tube between adjacent heat exchange components, and the heat exchange tube bundle is sealed and welded with heat exchanger casing side wall when passing through heat exchanger casing side wall, and the heat exchange tube bundle is arranged in the serpentine in heat exchanger casing, and the both ends of heat exchange tube bundle are connected with water inlet header, water outlet header respectively and are welded, the double pipe pass heat exchange tube bundle includes the first heat exchange tube and second heat exchange tube of the arrangement of first heat exchange tube and second heat exchange tube of the order of tube bundle, and the outer periphery of adjacent order arrangement first heat exchange tube and second heat exchange tube is uniformly arranged with multiple pairs of longitudinal symmetry H type fin, and heat exchanger casing is also connected with multiple soot blowers, the utility model discloses a smoke cooler, has the advantages of high heat exchange efficiency, small flow resistance, low dust wear and convenient ash removal.

Description

Technical Field

[0001] This utility model belongs to the field of industrial boiler technology, specifically relating to a dual-pass flue gas cooler. Background Technology

[0002] A flue gas cooler (also known as a flue gas chiller or flue gas desalination unit) is a heat exchange device used for industrial flue gas treatment. Its main function is to cool high-temperature flue gas, recover waste heat, and reduce the flue gas temperature to meet the process requirements of subsequent environmental protection treatments (such as desulfurization and dust removal), while simultaneously improving energy efficiency. In industrial boiler systems, flue gas coolers are specialized energy-saving devices used for waste heat recovery. Their main functions are to reduce exhaust gas temperature, recover sensible and latent heat from the flue gas, and improve boiler thermal efficiency.

[0003] This equipment cools high-temperature flue gas to below its dew point using a low-temperature medium, causing water vapor to condense, releasing latent heat and recovering thermal energy. It typically employs high-efficiency heat exchange elements such as spiral finned tubes and steel-aluminum composite finned tubes, combined with a split-type installation design for flexible deployment. The core structure includes the shell, heat exchange tubes, baffles, and cooling water circulation system. Some models enhance corrosion resistance through modular design, enamel coating, or copper-nickel brazing, and are equipped with an automatic control system to monitor operating parameters in real time. After application, it can reduce the exhaust gas temperature from approximately 200℃ to 40-70℃, improving the thermal efficiency of natural gas boilers by 8%-10%. Its technical solutions cover various modes, including direct mixing spray, counter-current heat exchange, and refrigerant circulation.

[0004] Existing patent CN219607139U discloses a flue gas cooler tube box. Fixed pipes are fixedly connected to the middle of both ends of the box. The interior of the box contains multiple equally spaced serpentine heat-conducting tubes. Heat-conducting plates are installed on both sides of the heat-conducting tubes, with slots and heat-conducting fins on the heat-conducting plates to allow flue gas to pass through. Compared to traditional bare tube arrays, the serpentine structure of the heat-conducting tubes can achieve higher heat exchange efficiency in a smaller space. By installing heat-conducting plates on the outside of the heat-conducting tubes, the contact area between the heat-conducting tubes and the flue gas is increased, thereby improving the heat exchange efficiency of the heat-conducting tubes and thus the overall heat exchange efficiency of the device. However, because this device reduces the area for flue gas flow, problems arise such as increased flue gas-side resistance, system negative pressure imbalance, decreased kiln / boiler output, increased air leakage, structural deformation, and even safety valve activation. Utility Model Content

[0005] To address the aforementioned problems, this invention provides a dual-tube flue gas cooler that offers high heat exchange efficiency and stable operation. The specific technical solution is as follows:

[0006] A dual-pass flue gas cooler includes a flue inlet and a flue outlet that are hermetically connected to a heat exchanger shell. The flue gas to be cooled enters the heat exchanger shell vertically downwards. The heat exchanger shell has a lower heat exchange assembly and an upper heat exchange assembly arranged from bottom to top. Each of the lower and upper heat exchange assemblies includes a heat exchange tube bundle located inside the heat exchanger shell and an inlet water header and an outlet water header located outside the heat exchanger shell. The lower and upper heat exchange assemblies are connected by a connecting pipe. The heat exchange tube bundle is sealed and welded to the side wall of the heat exchanger shell when it passes through it. The heat exchange tube bundle is arranged in a serpentine pattern inside the heat exchanger shell. The two ends of the heat exchange tube bundle are welded to the inlet water header and the outlet water header, respectively.

[0007] Each heat exchange assembly includes a heat exchange tube bundle comprising a first heat exchange tube and a second heat exchange tube arranged adjacent to each other, with multiple first heat exchange tubes arranged in a row along the horizontal direction and multiple second heat exchange tubes arranged in a row along the horizontal plane. Multiple H-shaped fins coplanar with the radial plane of the heat exchange tubes are evenly arranged on the outer periphery of the first and second heat exchange tubes.

[0008] The cooling medium in the heat exchange tube bundle flows in the opposite direction to the flue gas flow, and the heat exchanger shell is also connected to multiple soot blowers.

[0009] Furthermore, the first heat exchange tube / second heat exchange tube bends in a serpentine shape between the inlet and outlet water headers, including multiple rows of horizontal heat exchange tube bundles. Adjacent rows of the first heat exchange tube / second heat exchange tubes are arranged in parallel at equal intervals, thus forming a layered, multi-row, parallel tube bundle structure.

[0010] Furthermore, in the middle of the horizontal section of the heat exchange tube bundle, tube sheets are evenly arranged at intervals. The tube sheets are provided with an array of through holes arranged concentrically with the heat exchange tube bundle, allowing the first heat exchange tube / second heat exchange tube to pass through vertically. The array of through holes is clearance-fitted with the first heat exchange tube / second heat exchange tube. A short tube sleeve is also provided between the array of through holes and the first heat exchange tube / second heat exchange tube, and the short tube sleeve is fitted on the outer wall of the heat exchange tube.

[0011] Furthermore, the tube sheet is positioned near the side wall of the heat exchanger shell, and the horizontal sections of the adjacent layers or rows of the heat exchange tube bundles of the first heat exchange tubes / second heat exchange tubes pass vertically through the array through holes on the tube sheet and are connected by elbows.

[0012] Furthermore, the H-shaped fin includes two parallel and symmetrical fin plates. Each fin plate has two identical semi-circular arc-shaped grooves on one straight edge. The semi-circular arc-shaped grooves match the outer diameter of the heat exchange tube, so that the semi-circular arc-shaped grooves of the pair of H-shaped fins are tightly fitted into the outer walls of the first and second heat exchange tubes. The fin plates radiate outward along the radial direction of the heat exchange tubes and are symmetrically distributed along the axial direction of the first and second heat exchange tubes.

[0013] Furthermore, for the first and second heat exchange tubes that are adjacent to each other and arranged in sequence, the longitudinal symmetry planes of all H-shaped fins are coplanar.

[0014] Furthermore, the outlet water header of the lower heat exchange component and the inlet water header of the upper heat exchange component are located on the same side outside the heat exchanger shell, and the outlet water header of the lower heat exchange component and the inlet water header of the upper heat exchange component are connected by a connecting pipe.

[0015] Furthermore, the soot blower is connected to the heat exchanger shell by a flange or welding, and its acoustic waveguide extends into the heat exchanger shell for cleaning; along the flue gas flow direction, the first soot blower is located on the upper heat exchange assembly, and the second soot blower is located in the heat exchanger shell between the lower heat exchange assembly and the upper heat exchange assembly.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] 1. The dual-pass flue gas cooler of this utility model achieves the diversion of a large flow rate of cooling medium by setting two parallel first heat exchange tubes and second heat exchange tubes, i.e. dual-path diversion, so as to achieve the purpose of stabilizing the flow rate, while reducing the overall vibration of the equipment. Through flow field optimization, the system resistance is reduced by 20-30%.

[0018] 2. A tube sheet, constructed from a carbon steel frame and sandwiched in the middle, supports the heat exchange tubes. Elbows of varying sizes on both sides arrange the two tube passes into a square tube bundle layout, enabling simultaneous heat exchange in both passes. The heat then flows to the outlet manifold of the lower heat exchange assembly, and from there, through connecting pipes, reaches the upper heat exchange assembly for a second round of heat exchange. This device achieves the same heat exchange effect with a smaller volume. Heat exchange efficiency is increased by approximately 32% for the same volume.

[0019] 3. The dual-pass flue gas cooler of this utility model has an online ash cleaning function, reducing the annual maintenance time to less than 50 hours.

[0020] 4. Therefore, by adopting the dual-pass flue gas cooler of this utility model, the service life of the equipment is extended to more than 5 years, and the maintenance cost is greatly reduced. Attached Figure Description

[0021] Figure 1 This is a side view of the overall structure of a two-tube flue gas cooler.

[0022] Figure 2 This is a partial structural schematic diagram of a two-tube flue gas cooler viewed from the side.

[0023] Figure 3 This is a schematic diagram of the H-type fins in a two-pass flue gas cooler.

[0024] Figure 4This is a schematic diagram of the tube sheet structure of a two-pass flue gas cooler;

[0025] Wherein, 1-heat exchanger shell, 2-lower / upper heat exchange assembly, 3-H-shaped fins, 31-fin plate, 32-semi-circular groove, 4-first heat exchange tube, 5-second heat exchange tube, 6-inlet water header, 7-outlet water header, 8-connecting pipe, 9-tube sleeve, 10-tube sheet, 11-array through holes, 12-soot blower. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] The present invention proposes a high-efficiency heat exchange dual-tube flue gas cooler, such as... Figure 1 As shown, a two-tube flue gas cooler includes a flue inlet and a flue outlet that are hermetically connected to the heat exchanger shell 1. Figure 1 (Not shown in the drawing), the flue gas to be cooled enters vertically downward into the heat exchanger shell 1. The heat exchanger shell 1 contains a lower heat exchange assembly 2 and an upper heat exchange assembly 2 arranged from bottom to top. Both the lower and upper heat exchange assemblies 2 include a double-pass heat exchange tube bundle and an inlet water header 6 and an outlet water header 7 located outside the heat exchanger shell 1. The inlet end of the heat exchange tube bundle is welded to the inlet water header 6, and the other outlet end is welded to the outlet water header 7. When the heat exchange tube bundle passes through the side wall of the heat exchanger shell 1, it is sealed and welded to the side wall of the heat exchanger shell 1 to prevent air leakage. The cooling medium inside the heat exchange tube bundle flows in the opposite direction to the flue gas flow.

[0028] Each heat exchange assembly 2 has a double-pass heat exchange tube bundle including a first heat exchange tube 4 and a second heat exchange tube 5 arranged vertically adjacent to each other. The inner and outer diameters of the first heat exchange tube 4 and the second heat exchange tube 5 are the same. Multiple first heat exchange tubes 4 are arranged in a row in the horizontal direction to form a first group of heat exchange tubes. Multiple second heat exchange tubes 5 are arranged in a row in the horizontal direction to form a second group of heat exchange tubes. Each first heat exchange tube 4 and second heat exchange tube 5 bends in a serpentine shape between the inlet header 6 and the outlet header 7, including multiple rows of horizontal sections of heat exchange tube bundles. Adjacent rows of first heat exchange tubes 4 and second heat exchange tubes 5 are arranged in parallel with equal spacing. The horizontal sections of adjacent layers or connected rows of heat exchange tube bundles of first heat exchange tubes 4 and second heat exchange tubes 5 are connected by elbows, so that each first heat exchange tube 4 and second heat exchange tube 5 is arranged in a meandering manner from bottom to top. The horizontal sections of adjacent rows or columns of heat exchange tube bundles are arranged in parallel at equal intervals along the flue gas flow direction, forming a square layout within the heat exchanger shell 1, thus forming a layered, multi-row, parallel tube bundle structure.

[0029] like Figure 3 As shown, the outer periphery of the first heat exchange tube 4 and the second heat exchange tube 5 arranged adjacent to each other is provided with symmetrical H-shaped fins 3. The H-shaped fin 3 includes two parallel and symmetrical fin plates 31. Each fin plate 31 also has two identical semi-circular arc-shaped grooves 32 on one straight edge. The semi-circular arc-shaped grooves 32 match the outer diameter of the heat exchange tube, so that the semi-circular arc-shaped grooves 32 of a pair of H-shaped fins 3 are tightly engaged with the outer wall of the first heat exchange tube 4 and the second heat exchange tube 5. The fin plates 31 radiate outward along the radial direction of the pipe and are symmetrically distributed along the axial direction of the first heat exchange tube 4 and the second heat exchange tube 5. Multiple H-shaped fins 3 are evenly distributed along the outer periphery of the first heat exchange tube 4 and the second heat exchange tube 5 in the same horizontal plane. Specifically, the H-shaped fins 3 are distributed on the outer periphery of the horizontal section of the first heat exchange tube 4 and the second heat exchange tube 5. For the first heat exchange tube 4 and the second heat exchange tube 5 that are adjacent to each other, the longitudinal symmetry planes of all H-shaped fins 3 are coplanar, that is, the fin symmetry axes of the two tubes are in the same plane perpendicular to the airflow direction, forming a continuous fin array. This can enhance the heat exchange efficiency and reduce the dead corners of ash accumulation.

[0030] like Figure 1 and Figure 4 As shown, tube sheets 10 are evenly spaced apart in the middle of the horizontal heat exchanger tube bundle. The tube sheets 10 have an array of through holes 11 arranged concentrically with the heat exchanger tube bundle, allowing the first heat exchanger tube 4 / second heat exchanger tube 5 to pass through vertically. The array of through holes 11 is clearance-fitted with the first heat exchanger tube 4 / second heat exchanger tube 5. A short tube sleeve 9 is also provided between the array of through holes 11 and the first heat exchanger tube 4 / second heat exchanger tube 5. The short tube sleeve 9 fits over the outer wall of the heat exchanger tube, providing a radial fulcrum for the heat exchanger tube, so that the first heat exchanger tube 4 / second heat exchanger tube 5 is stably fixed within the array of through holes 11 on the tube sheet 10 through the tube sleeve 9. In this embodiment, preferably, one tube sheet 10 is provided near the heat exchanger shell. If the heat exchanger tube bundle is too long, one or more evenly arranged tube sheets 10 can be added to the longer tube bundle.

[0031] The lower and upper heat exchange components 2 are connected by a connecting pipe 8. Specifically, the outlet water header 7 of the lower heat exchange component 2 and the inlet water header 6 of the upper heat exchange component 2 are located on the same side outside the heat exchanger shell 1, and the outlet water header 7 of the lower heat exchange component 2 and the inlet water header 6 of the upper heat exchange component 2 are connected by a connecting pipe 8.

[0032] Multiple soot blowers 12 are installed outside the heat exchanger shell 1. Each soot blower 12 is connected to the heat exchanger shell 1 by a flange or welding, and its acoustic waveguide extends into the heat exchanger shell 1 for cleaning. Along the flue gas flow direction, the first soot blower 12 is located on the upper heat exchange component 2, and the second soot blower 12 is located inside the shell between the lower heat exchange component 2 and the upper heat exchange component 2. The soot blowers 12 are acoustic soot blowers, which are non-contact cleaning devices that use high-intensity sound waves to remove ash accumulated in the heat exchanger and other equipment. They use compressed air or steam to drive a sound wave generator to generate sound waves of a specific frequency, causing the ash particles to vibrate, fatigue, and fall off, and then be carried away by the flue gas or settled and discharged.

[0033] Preferably, in the heat exchange components at the top of the device, the easily corroded areas are made of corrosion-resistant materials. When adjusting the temperature of the cooling medium in the heat exchange tubes, the temperature range of the flue gas acid dew point corrosion is avoided, so that it always operates above the dew point temperature, thus preventing corrosion and leakage problems in the heat exchange pipeline.

[0034] The implementation process of this embodiment of a highly stable and efficient heat exchange dual-tube flue gas cooler is as follows:

[0035] Cooling water enters from the inlet header of the lower heat exchange assembly and flows through two parallel heat exchange tubes, i.e., a dual-path flow distribution, to divert the large flow of cooling medium, thereby stabilizing the flow rate and reducing overall equipment vibration. A tube sheet, made of carbon steel and sandwiched in the middle, supports the heat exchange tubes. Large and small elbows on both sides arrange the two tube passes into a square tube bundle layout, enabling simultaneous heat exchange in both passes. The water then converges at the outlet header of the lower heat exchange assembly and, through connecting pipes, reaches the upper heat exchange assembly for a second round of heat exchange.

[0036] The advantage of this device is that the two tube passes are arranged alternately and operate simultaneously, and the tube holes adopt a square layout to maximize the use of the internal space of the flue gas cooler, arrange the most finned heat exchange tubes, and achieve the highest heat exchange efficiency at the lowest cost.

[0037] In common single-tube flue gas coolers, the abrupt change in cross-sectional area from the tube header to the heat exchange tubes leads to significant changes in flow velocity, which can easily cause equipment vibration, damage, reduced service life, and increased maintenance costs.

[0038] Using this device, the same heat exchange effect can be achieved with a smaller volume. Heat exchange efficiency is increased by approximately 32% for the same volume, and tube-side fluid resistance is reduced by 20-30%. This dual-tube flue gas cooler can be used for waste heat recovery from flue gas in boilers, blast furnaces, heating furnaces, RTO furnaces, and kilns.

[0039] Furthermore, if the embodiments involve descriptions such as "first," "second," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relation to the specification. The significance or implied number of the indicated technical features is not specified. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

Claims

1. A double-pass flue gas cooler, comprising a flue inlet and a flue outlet hermetically connected to a heat exchanger shell (1), wherein the flue gas to be cooled enters vertically downward into the heat exchanger shell (1), characterized in that, The heat exchanger housing (1) is provided with a lower heat exchange assembly (2) and an upper heat exchange assembly (2) from bottom to top. The lower / upper heat exchange assembly (2) includes a heat exchange tube bundle located inside the heat exchanger housing (1) and an inlet water header (6) and an outlet water header (7) located outside the heat exchanger housing (1). The lower / upper heat exchange assembly (2) is connected to each other by a connecting pipe (8). When the heat exchange tube bundle passes through the side wall of the heat exchanger housing (1), it is sealed and welded to the side wall of the heat exchanger housing (1). The heat exchange tube bundle is arranged in a serpentine pattern inside the heat exchanger housing (1). The two ends of the heat exchange tube bundle are welded to the inlet water header (6) and the outlet water header (7) respectively. Each heat exchange assembly (2) includes a heat exchange tube bundle comprising a first heat exchange tube (4) and a second heat exchange tube (5) arranged adjacent to each other, and multiple first heat exchange tubes (4) are arranged in a row along the horizontal direction, and multiple second heat exchange tubes (5) are arranged in a row along the horizontal plane. Multiple H-shaped fins (3) coplanar with the radial plane of the heat exchange tubes are evenly arranged on the outer periphery of the first heat exchange tubes (4) and the second heat exchange tubes (5). The cooling medium in the heat exchange tube bundle flows in the opposite direction to the flue gas flow, and the heat exchanger shell (1) is also connected to a plurality of soot blowers (12).

2. A dual-pass flue gas cooler according to claim 1, characterized in that, The first heat exchange tube (4) / second heat exchange tube (5) bends in a serpentine shape between the inlet header (6) and the outlet header (7), including multiple rows of horizontal heat exchange tube bundles. The adjacent rows of first heat exchange tubes (4) / second heat exchange tubes (5) are arranged in parallel at equal intervals, thus forming a layered, multi-row, parallel tube bundle structure.

3. A dual-pass flue gas cooler according to claim 1, characterized in that, Located in the middle of the horizontal section of the heat exchange tube bundle, there are tube sheets (10) spaced apart from each other. The tube sheets (10) are provided with array through holes (11) arranged concentrically with the heat exchange tube bundle, which allow the first heat exchange tube (4) / second heat exchange tube (5) to pass through vertically. The array through holes (11) are clearance-fitted with the first heat exchange tube (4) / second heat exchange tube (5). A short tube sleeve (9) is also provided between the array through holes (11) and the first heat exchange tube (4) / second heat exchange tube (5), and the short tube sleeve (9) is fitted on the outer wall of the heat exchange tube.

4. A dual-pass flue gas cooler according to claim 3, characterized in that, The tube sheet (10) is located near the side wall of the heat exchanger shell (1). The horizontal sections of the adjacent layers or adjacent rows of heat exchange tube bundles of the first heat exchange tube (4) / second heat exchange tube (5) pass vertically through the array through holes (11) on the tube sheet (10) and are connected by elbows (13).

5. A dual-pass flue gas cooler according to claim 1, characterized in that, The H-shaped fin (3) includes two parallel and symmetrical fin plates (31). Each fin plate (31) has two identical semi-circular grooves (32) on one straight edge. The semi-circular grooves (32) match the outer diameter of the heat exchange tube, so that the semi-circular grooves (32) of a pair of H-shaped fins (3) are tightly fitted into the outer wall of the first heat exchange tube (4) and the second heat exchange tube (5). The fin plates (31) radiate outward along the radial direction of the heat exchange tube and are symmetrically distributed along the axial direction of the first heat exchange tube (4) and the second heat exchange tube (5).

6. A dual-pass flue gas cooler according to claim 5, characterized in that, For the first heat exchange tube (4) and the second heat exchange tube (5) that are arranged vertically and sequentially, the longitudinal symmetry planes of all H-shaped fins (3) are coplanar.

7. A dual-pass flue gas cooler according to claim 1, characterized in that, The outlet water header (7) of the lower heat exchange component (2) and the inlet water header (6) of the upper heat exchange component (2) are located on the same side outside the heat exchanger shell (1). The outlet water header (7) of the lower heat exchange component (2) and the inlet water header (6) of the upper heat exchange component (2) are connected by a connecting pipe (8).

8. A dual-pass flue gas cooler according to claim 1, characterized in that, The soot blower (12) is connected to the heat exchanger shell (1) by flange or welding, and its acoustic waveguide extends into the heat exchanger shell (1) for cleaning. Along the flue gas flow direction, the first soot blower (12) is located above the upper heat exchange assembly (2), and the second soot blower (12) is located in the heat exchanger shell between the lower heat exchange assembly (2) and the upper heat exchange assembly (2).

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