Novel combined low-temperature economizer

Abstract

The utility model belongs to the technical field of flue gas recovery, and particularly relates to a novel combined low-temperature economizer which comprises an inlet flue and an outlet flue, and an inlet radial heat pipe heat exchange pipe set, a dividing wall type heat exchange pipe set and an outlet radial heat pipe heat exchange pipe set are sequentially arranged between the inlet flue and the outlet flue in the flue gas direction. A first inlet water collecting tank is arranged at the outlet radial heat pipe heat exchange pipe set, a second inlet water collecting tank is arranged between the dividing wall type heat exchange pipe set and the outlet radial heat pipe heat exchange pipe set, and an outlet water collecting tank is arranged at the inlet radial heat pipe heat exchange pipe set. The radial heat pipes are arranged in the front row of the windward side of the coal economizer, so that a certain heat exchange effect can be provided for the coal economizer, meanwhile, the anti-abrasion effect can be achieved, and the layout is more compact. Meanwhile, the radial heat pipe sets are arranged in a staggered mode, when smoke passes through each row of radial heat pipes, the flow direction of the smoke can be greatly changed, disturbance of the smoke is enhanced, and the heat transfer coefficient of the low-temperature economizer is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas recovery, in particular to a novel combined low-temperature economizer. Background Art

[0002] As a good heat exchange equipment, low-temperature economizer is widely used in the boiler field. After the low-temperature economizer has been running for a long time, the dust particles in the flue gas have a strong scouring effect on the front heat exchange tubes. After a long time of operation, the front heat exchange tubes are prone to wear, resulting in leakage or bursting of the heat exchange tubes. At the same time, for flue gas containing high sulfuric acid vapor, as the flue gas passes through the low-temperature economizer, its flue gas temperature gradually decreases. When the flue gas temperature at the rear heat exchange tube is lower than the dew point of sulfuric acid vapor, the vapor containing sulfuric acid will condense on the rear heat exchange tube into liquid containing sulfuric acid, causing serious corrosion to the heating surface.

[0003] Patent CN202220910219.5 discloses a flue gas heat exchanger. The patent provides a combined flue gas heat exchanger without false tubes, which combines conventional partition wall heat exchangers with heat pipe heat exchangers. The heat pipe heat exchanger is arranged in the wear-prone area, and the anti-wear false tube setting is cancelled. In this way, even if the wear-prone heat exchange tube bundle is worn or even leaks, the leaked working fluid is only a few kilograms, which evaporates quickly in the flue, will not cause dust accumulation and blockage of the heat exchanger, nor will it cause the withdrawal of the entire module of the heat exchanger, and the heat exchange effect is very small. The heat exchange tube bundle in the non-key wear area adopts conventional flue gas-tube wall-water direct heat exchange, which has high heat exchange efficiency. This patent solves the problem that the front row of heat exchange tubes of the flue gas heat exchanger are easy to wear and cause leakage of heat exchange medium, but because its heat pipe heat exchanger must occupy a part of the space outside the flue as a condensation section, it has high requirements for the installation site of the heat exchanger. At the same time, the patent does not consider how to avoid low-temperature corrosion of the rear row of heat exchange tubes. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a novel combined low-temperature economizer, which solves the problems of anti-wear and anti-low-temperature corrosion requirements of the low-temperature economizer without sacrificing heat exchange efficiency.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a novel combined low-temperature economizer, comprising an inlet flue and an outlet flue, wherein an inlet radial heat pipe heat exchange tube group, a partition wall heat exchange tube group and an outlet radial heat pipe heat exchange tube group are sequentially arranged along the flue gas direction between the inlet flue and the outlet flue, and the inlet radial heat pipe heat exchange tube group, the partition wall heat exchange tube group and the outlet radial heat pipe heat exchange tube group are all arranged in multiple rows and columns;

[0006] A first inlet water collecting box is provided at the last row of heat exchange tubes of the outlet radial heat pipe heat exchange tube group along the flue gas direction, a second inlet water collecting box is provided between the partition wall heat exchange tube group and the outlet radial heat pipe heat exchange tube group, and an outlet water collecting box is provided at the first row of heat exchange tubes of the inlet radial heat pipe heat exchange tube group.

[0007] Furthermore, the heat exchange tubes of the partition-type heat exchange tube group and the outlet radial heat pipe heat exchange tube group are arranged in series, and the heat exchange tubes of the inlet radial heat pipe heat exchange tube group are arranged in staggered rows.

[0008] Furthermore, the radial heat pipes used in the inlet radial heat pipe heat exchange tube group and the outlet radial heat pipe heat exchange tube group include four parts: a sleeve, a heat exchange tube, a heat transfer medium and a fin. The sleeve is arranged outside the heat exchange tube to form a closed annular space in the middle. The heat transfer medium flows in the annular space, and the fin is arranged outside the sleeve.

[0009] Furthermore, the heat transfer medium is desalted water.

[0010] Compared with the prior art, the utility model provides a new type of combined low-temperature economizer, which has the following beneficial effects:

[0011] 1. The utility model arranges radial heat pipes in the front row of the windward side of the economizer. The radial heat pipes can not only provide a certain heat exchange effect for the economizer, but also play an anti-wear role. Compared with the traditional low-temperature economizer that requires additional anti-wear false pipes, the combined low-temperature economizer has a compact layout. At the same time, because the radial heat pipe group is arranged in a staggered manner, the flue gas flow direction will change significantly when the flue gas passes through each row of radial heat pipes, which enhances the disturbance of the flue gas and improves the heat transfer coefficient of the low-temperature economizer;

[0012] 2. The utility model sets two cooling water inlet headers. When the flue gas outlet temperature is lower than the dew point of sulfuric acid vapor, the cooling water volume of the tail inlet header can be reduced to reduce the heat exchange of the outlet radial heat pipe heat exchange tube group. This increases the tube wall temperature of the outlet radial heat pipe heat exchange tube group and prevents sulfuric acid vapor from condensing on the tube wall and causing low-temperature corrosion.

[0013] 3. The low-temperature economizer of the utility model adopts radial heat pipe heat exchange tube groups at both the inlet and outlet. Even if the inlet radial heat pipe heat exchange tube group is worn or the outlet radial heat pipe heat exchange tube group is low-temperature corroded, it will only cause the heat transfer medium in the casing to leak, and the cooling water will not leak into the flue, ensuring the safe operation of the low-temperature economizer;

[0014] 4. Compared with the traditional heat pipe low-temperature economizer, the combined low-temperature economizer of the utility model occupies less space, especially there is no need to set up an additional condensation section outside the flue, which is more friendly to site requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structural arrangement of the utility model;

[0016] Figure 2 It is a side view structural schematic diagram of the utility model;

[0017] Figure 3 It is a schematic diagram of the structure of the radial heat pipe of the utility model.

[0018] In the figure: 1-inlet flue, 2-inlet radial heat pipe heat exchange tube group, 3-partition wall heat exchange tube group, 4-first inlet water collecting tank, 5-second inlet water collecting tank, 6-outlet radial heat pipe heat exchange tube group, 7-outlet flue, 8-outlet water collecting tank, 9-casing, 10-heat exchange tube, 11-heat transfer medium, 12-fin. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] See also Figure 1-3 In this embodiment: a novel combined low-temperature economizer includes an inlet flue 1 and an outlet flue 7. Between the inlet flue 1 and the outlet flue 7 is a heat exchange area, where heat exchange tubes are arranged. Along the flue gas direction, there are inlet radial heat pipe heat exchange tube group 2, partition wall heat exchange tube group 3 and outlet radial heat pipe heat exchange tube group 6. The inlet radial heat pipe heat exchange tube group 2, partition wall heat exchange tube group 3 and outlet radial heat pipe heat exchange tube group 6 are all arranged in multiple rows and columns. The inlet radial heat pipe heat exchange tube group 2 and the outlet radial heat pipe heat exchange tube group 6 not only have heat exchange function, but also play an anti-wear role.

[0021] Further Figure 2 As shown, the heat exchange tubes of the partition-type heat exchange tube group 3 and the outlet radial heat exchange tube group 6 are arranged in series, and the heat exchange tubes of the inlet radial heat exchange tube group 2 are arranged in staggered rows. When the flue gas passes through the inlet radial heat exchange tube group, since the tube group is arranged in staggered rows, the direction of the flue gas will change significantly when the flue gas passes through each row of radial heat pipes, which enhances the disturbance of the flue gas and improves the heat transfer coefficient.

[0022] Further Figure 1As shown, the low-temperature economizer of the utility model has two water inlet headers, including a first inlet header 4 and a second inlet header 5. The first inlet header 4 is located at the last row of heat exchange tubes of the outlet radial heat pipe heat exchange tube group 6 along the flue gas direction, and the second inlet header 5 is located between the partition wall heat exchange tube group 3 and the outlet radial heat pipe heat exchange tube group 6. At the same time, an outlet header 8 is provided at the first row of heat exchange tubes of the inlet radial heat pipe heat exchange tube group 2. Cooling water flows in from the first inlet header 4 and the second inlet header 5, and flows out from the outlet header 8 after passing through the inlet radial heat pipe heat exchange tube group 2, the partition wall heat exchange tube group 3 and the outlet radial heat pipe heat exchange tube group 6, and its flow direction is opposite to the flue gas direction.

[0023] When the flue gas outlet temperature is lower than the dew point of sulfuric acid vapor, the cooling water volume of the first inlet water collecting tank 4 can be reduced to reduce the heat exchange capacity of the outlet radial heat pipe heat exchange tube group, thereby increasing the tube wall temperature of the outlet radial heat pipe heat exchange tube group to avoid condensation of sulfuric acid vapor on the tube wall and causing low-temperature corrosion.

[0024] Further Figure 3 As shown, the radial heat pipes used in the inlet radial heat pipe heat exchange tube group 2 and the outlet radial heat pipe heat exchange tube group 6 include four parts: a sleeve 9, a heat exchange tube 10, a heat transfer medium 11 and a fin 12. The sleeve 9 is sleeved outside the heat exchange tube 10 to form a closed annular space in the middle. The heat transfer medium 11 flows in the annular space, and the fin 12 is arranged outside the sleeve 9. In this embodiment, the heat transfer medium 11 is deionized water. When the inlet radial heat pipe heat exchange tube group 2 is worn, or the outlet radial heat pipe heat exchange tube group 6 is low-temperature corroded, it will only cause the heat transfer medium 11 in the annular space between the sleeve 9 and the heat exchange tube 10 to leak. After the heat transfer medium 11 leaks, it will evaporate due to heat and be discharged with the flue gas. In this way, the cooling water in the heat exchange tube will not leak into the flue, avoiding the blockage of the economizer by ash accumulation, and ensuring the safe operation of the low-temperature economizer.

[0025] The working principle of the utility model is:

[0026] After the low-temperature economizer is installed, the flue gas enters the low-temperature economizer from the inlet flue 1, and exchanges heat with the inlet radial heat pipe heat exchange tube group 2, the partition wall heat exchange tube group 3 and the outlet radial heat pipe heat exchange tube group 6 in turn. The flue gas after heat exchange leaves the low-temperature economizer from the outlet flue 7.

[0027] The cooling water used as the heat exchange medium adopts reverse flow to enhance heat exchange. The cooling water enters the low-temperature economizer from the first inlet header 4 and the second inlet header 5, and flows through the outlet radial heat pipe heat exchange tube group 6, the partition wall heat exchange tube group 3 and the inlet radial heat pipe heat exchange tube group 2 in turn for heat exchange. The cooling water after heat exchange leaves the low-temperature economizer from the outlet header 8. When the flue gas outlet temperature is lower than the dew point of sulfuric acid vapor, the amount of cooling water entering the heat exchanger through the first inlet header 4 is reduced, and the heat exchange amount of the outlet radial heat pipe heat exchange tube group 6 is reduced, thereby increasing the tube wall temperature of the outlet radial heat pipe heat exchange tube group 6, and preventing sulfuric acid vapor from condensing on the tube wall and causing low-temperature corrosion.

[0028] The inlet and outlet radial heat pipe heat exchange tube groups and partition-type heat exchange tube groups can use different fin types. The heat exchange area is increased by adding fins on the flue gas side of the radial heat pipe used in the inlet and outlet radial heat pipe heat exchange tube groups, while the water side uses a base tube outer casing to perform condensation side heat exchange. When the radial heat pipe exchanges heat, the heat of the flue gas is transferred to the heat transfer medium 11 in the casing through the fins 12 and the casing 9. The heat transfer medium 11 boils and becomes steam to fill the casing. When the cooling water flows from the heat exchange tube 10, the steam of the heat transfer medium 11 recondenses into liquid outside the heat exchange tube 10 and releases heat to heat the cooling water, thereby completing the circulation of the heat transfer medium 11.

[0029] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A new type of combined low-temperature economizer, characterized by: It includes an inlet flue and an outlet flue, wherein an inlet radial heat pipe heat exchange tube group, a partition wall heat exchange tube group and an outlet radial heat pipe heat exchange tube group are sequentially arranged between the inlet flue and the outlet flue along the flue gas direction, and the inlet radial heat pipe heat exchange tube group, the partition wall heat exchange tube group and the outlet radial heat pipe heat exchange tube group are all arranged in multiple rows and columns; A first inlet water collecting box is provided at the last row of heat exchange tubes of the outlet radial heat pipe heat exchange tube group along the flue gas direction, a second inlet water collecting box is provided between the partition wall heat exchange tube group and the outlet radial heat pipe heat exchange tube group, and an outlet water collecting box is provided at the first row of heat exchange tubes of the inlet radial heat pipe heat exchange tube group.

2. A novel combined low-temperature economizer according to claim 1, characterized in that: The heat exchange tubes of the partition-type heat exchange tube group and the outlet radial heat pipe heat exchange tube group are arranged in series, and the heat exchange tubes of the inlet radial heat pipe heat exchange tube group are arranged in staggered rows.

3. A novel combined low-temperature economizer according to claim 1, characterized in that: The radial heat pipes used in the inlet radial heat pipe heat exchange tube group and the outlet radial heat pipe heat exchange tube group include four parts: a sleeve, a heat exchange tube, a heat transfer medium and a fin. The sleeve is arranged outside the heat exchange tube to form a closed annular space in the middle. The heat transfer medium flows in the annular space, and the fin is arranged outside the sleeve.

4. A novel combined low-temperature economizer according to claim 3, characterized in that: The heat transfer medium is desalted water.

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