Spraying heat exchange system capable of achieving flue gas water balance

Abstract

The utility model discloses a spraying heat exchange system capable of achieving smoke water balance, and belongs to the technical field of energy conservation and environmental protection. The flue gas waste heat recovery device solves the problem that a water treatment system needs to be additionally arranged independently to discharge water because the liquid level in a spray tower is unbalanced due to the fact that flue gas waste heat is recovered through spray heat exchange in the prior art. Comprising a spraying tower, a dividing wall type heat exchanger and a vacuum phase change heat exchanger, a flue gas inlet is formed in the lower portion of the spraying tower, the spraying tower is of a single-layer single-section spraying type structure or a multi-layer segmented spraying type structure, and when the spraying tower is of the single-layer single-section spraying type structure, a heat release side outlet of the dividing wall type heat exchanger is communicated with a spraying water inlet of the spraying tower; a mixed water outlet in the bottom of the spray tower is communicated with a water inlet of the vacuum phase change heat exchanger; and a water outlet of the vacuum phase change heat exchanger is communicated with a heat release side inlet of the dividing wall type heat exchanger. By utilizing a flash heat exchange principle, condensed water can be dynamically flashed out of spray liquid, the stability of the liquid level is kept, water balance in the spray tower is realized, and water resources are saved while heat exchange is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of spray heat exchange systems that can realize flue gas water balance, belong to energy-saving and environment-protecting technical field. BACKGROUND

[0002] At present stage, low-temperature flue gas waste heat recovery is more directly heat exchanged using spray heat exchange, and the circulation heat exchange of spray water in spray tower is realized through partition wall heat exchanger, that is, the combination of spray tower+partition wall heat exchanger realizes the function of spray heat exchange by reducing spray water temperature through partition wall heat exchanger as heat transfer tool.In the process of flue gas waste heat recovery, flue gas is continuously cooled by spray water spraying in spray tower, and the spray water after heat absorption accumulates in tower pool, and then enters partition wall heat exchanger to release heat, and the spray water after heat release continues to circulate into spray tower.In the process of cooling flue gas, the water vapor saturation pressure is also continuously reduced, that is, with the reduction of flue gas temperature, a large amount of water vapor will condense, and the condensed water will accumulate in the tower pool of spray tower with time, which will cause the spray water level in the tower pool of spray tower to increase continuously, resulting in unbalanced spray water level in spray tower and even shutdown.

[0003] In order to maintain the balance of spray water level in spray tower, the water in tower pool needs to be properly discharged, but because it is water condensed from flue gas, the condensed water is dirty and cannot be directly discharged, so a water treatment system needs to be added to treat the water before use or discharge, which seriously increases the cost of equipment and operation. INVENTION CONTENTS

[0004] The utility model discloses to solve the problem of unbalanced liquid level in spray tower caused by the existing spray heat exchange to recover flue gas waste heat, and to provide a spray heat exchange system capable of realizing flue gas water balance.

[0005] The utility model discloses the technical scheme adopted to solve the above technical problems is:

[0006] A spray heat exchange system capable of realizing flue gas water balance, comprising a spray tower, a partition wall heat exchanger and a vacuum phase change heat exchanger, a flue gas inlet is arranged at the lower part of the spray tower, wherein the spray tower is a single-layer single-section spray structure or a multi-layer segmented spray structure,

[0007] When the spray tower is a single-layer single-section spray structure, the heat release side outlet of the partition wall heat exchanger is communicated with the spray water inlet of the spray tower, the mixed water outlet at the bottom of the spray tower is communicated with the water inlet of the vacuum phase change heat exchanger, and the water outlet of the vacuum phase change heat exchanger is communicated with the heat release side inlet of the partition wall heat exchanger.

[0008] When the spray tower is a multi-layer segmented spray structure, N spray chambers are arranged in the spray tower from bottom to top, each adjacent two spray chambers are communicated by a liquid discharge pipe, a smoke discharge channel is arranged between each adjacent two spray chambers, the bottom spray chamber is connected with a vacuum phase change heat exchanger, each other spray chamber is connected with a partition wall heat exchanger, the mixed water outlet at the bottom of the bottom spray chamber is communicated with the water inlet of the vacuum phase change heat exchanger, the water outlet of the vacuum phase change heat exchanger is communicated with the spray water inlet at the upper part of the bottom spray chamber, the heat release side outlet of each partition wall heat exchanger is communicated with the spray water inlet of the corresponding spray chamber, and the mixed water outlet of each spray chamber is communicated with the heat release side inlet of the corresponding partition wall heat exchanger.

[0009] Further, when the spray tower is a single-layer single-segment spray structure, an alkali adding tank is arranged between the mixed water outlet at the bottom of the spray tower and the water inlet of the vacuum phase change heat exchanger.

[0010] Further, when the spray tower is a multi-layer segmented spray structure, an alkali adding tank is arranged between the mixed water outlet at the bottom of the bottom spray chamber and the water inlet of the vacuum phase change heat exchanger, and an alkali adding tank is arranged between the mixed water outlet at the bottom of each other spray chamber and the heat release side inlet of the corresponding partition wall heat exchanger.

[0011] Further, a liquid discharge valve is arranged on each liquid discharge pipe.

[0012] Further, when the spray tower is a single-layer single-segment spray structure, a first conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the spray tower and the water inlet of the vacuum phase change heat exchanger, and a second conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger and the heat release side inlet of the partition wall heat exchanger.

[0013] Further, the first conveying pump is arranged between the alkali adding tank and the partition wall heat exchanger.

[0014] Further, when the spray tower is a multi-layer segmented spray structure, a third conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the bottom spray chamber and the water inlet of the vacuum phase change heat exchanger, a fourth conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of each other spray chamber and the heat release side inlet of the corresponding partition wall heat exchanger, and a fifth conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger and the spray water inlet at the upper part of the bottom spray chamber.

[0015] Further, the third conveying pump is arranged between the alkali adding tank and the vacuum phase change heat exchanger on the connecting pipeline, and the fourth conveying pump is arranged between the alkali adding tank and the partition wall heat exchanger on the connecting pipeline.

[0016] Compared with the prior art, the utility model has the following effects:

[0017] By setting up vacuum phase change heat exchanger, using flash heat exchange principle, condensate water can be dynamically flashed out to spray liquid, liquid level is kept stable, balance of water in spray tower is realized, dirty condensate water is replaced by distilled water, heat exchange can be realized while water resource can be saved.

[0018] But because the cost of the partition wall type heat exchanger is lower, the economy is better, and the cost of the vacuum phase change heat exchanger is higher, so the cost is higher, therefore, if the vacuum phase change heat exchanger is used to completely replace the partition wall type heat exchanger, the cost of the whole flue gas waste heat exchange system will be too high, so it is not suitable for popularization and use, for this, in the utility model, one vacuum phase change heat exchanger is used in cooperation with one or more partition wall type heat exchangers to extract the waste heat of low temperature flue gas, the vacuum phase change heat exchanger is used to maintain the balance of liquid level in the spray tower, in the actual construction process, only the flash evaporation rate required is calculated according to the condensate water speed of the spray tower, then the vacuum phase change heat exchanger with appropriate size is selected, the vacuum phase change heat exchanger can realize heat exchange to a certain extent while maintaining the balance of liquid level in the spray tower, the partition wall type heat exchanger is used to bear the heat exchange purpose of the whole flue gas waste heat exchange system, so the cost is effectively reduced.

[0019] After the operation of the flue gas waste heat exchange system, the spray water liquid surface balance in the spray tower can be maintained while the waste heat is extracted, so the water treatment system does not need to be additionally arranged.

[0020] After the heat exchange system is implemented, the flue gas exhaust temperature of the power plant can be reduced to 30-15 DEG C at the lowest. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 It is a system composition schematic view of the spray heat exchange system capable of realizing flue gas balance (when the spray tower is single layer single section spray type structure) of the utility model;

[0022] Fig. 2 It is a system composition schematic view of the spray heat exchange system capable of realizing flue gas balance (when the spray tower is multi-layer section spray type structure) of the utility model.

[0023] In the drawing:

[0024] 1, spray tower, 2, partition wall type heat exchanger, 3, vacuum phase change heat exchanger, 4, flue gas inlet, 5, sprayer, 6, liquid discharge pipe, 7, flue gas discharge channel, 8, flue gas discharge port, 9, first alkali adding box, 10, second alkali adding box. DETAILED DESCRIPTION

[0025] Specific implementation one: combined with Figs. 1-2The embodiments are used for clearly and completely describing the technical scheme in the utility model, obviously, the described embodiments are only part of the utility model, rather than all the embodiments, based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the protection scope of the utility model.

[0026] It should be noted that the descriptions of the utility model about "front", "back", "left", "right", "inner", "outer", "left side", "right side", "upper part", "lower part", "top", "bottom" and the like are defined based on the position or relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and are not intended to indicate or imply that the described structure must be constructed and operated in a particular position, therefore, it cannot be understood as a limitation on the utility model. In the description of the utility model, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0027] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For the person skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0028] A spray heat exchange system capable of realizing flue gas balance, comprising a spray tower 1, a partition wall heat exchanger 2 and a vacuum phase change heat exchanger 3, a flue gas inlet 4 is arranged at the lower part of the spray tower 1, wherein the spray tower 1 is a single-layer single-segment spray structure or a multi-layer segmented spray structure,

[0029] When the spray tower 1 is a single-layer single-segment spray structure, the heat release side outlet of the partition wall heat exchanger 2 is in communication with the spray water inlet of the spray tower 1, the mixed water outlet at the bottom of the spray tower 1 is in communication with the water inlet of the vacuum phase change heat exchanger 3, and the water outlet of the vacuum phase change heat exchanger 3 is in communication with the heat release side inlet of the partition wall heat exchanger 2;

[0030] When the spray tower 1 is a multi-layer segmented spray structure, N layers of spray chambers are arranged in the spray tower 1 from bottom to top, the lower parts of each adjacent two spray chambers are communicated through the liquid discharge pipes 6, the smoke discharge channels 7 are arranged in communication between each adjacent two spray chambers, the bottom layer of spray chambers is connected and arranged with a vacuum phase change heat exchanger 3, each layer of spray chambers is connected and arranged with an inter-wall heat exchanger 2, the mixed water outlet at the bottom of the bottom layer of spray chambers is communicated with the water inlet of the vacuum phase change heat exchanger 3, the water outlet of the vacuum phase change heat exchanger 3 is communicated with the spray water inlet at the upper part of the bottom layer of spray chambers, the heat release side outlet of each inter-wall heat exchanger 2 is communicated with the spray water inlet of the corresponding spray chamber, the mixed water outlet of each layer of spray chambers is communicated with the heat release side inlet of the corresponding inter-wall heat exchanger 2, and a smoke discharge port 8 is arranged at the top of the top layer of spray chambers.

[0031] The spray tower 1 is provided with the sprayers 5 to realize spraying. The bottom of the vacuum phase change heat exchanger 3 is provided with a condensate water discharge port.

[0032] The vacuum phase change heat exchanger 3 and the heat absorption side of the inter-wall heat exchanger 2 are respectively connected with heated water.

[0033] When the spray tower 1 is a multi-layer segmented spray structure, N layers of spray chambers are arranged in the spray tower 1 from bottom to top, the lower parts of each adjacent two spray chambers are communicated through the liquid discharge pipes 6, the smoke discharge channels 7 are arranged in communication between each adjacent two spray chambers, that is, the N layers of spray chambers are connected in series. When the upper layer of spray water increases, a part of the upper layer of spray water is discharged to the lower layer of spray chambers through the liquid discharge pipes 6, and finally discharged to the bottom layer of spray chambers, and then treated by the vacuum phase change heat exchanger 3. The original flue gas enters from the bottom layer of spray chambers, is cooled by the spray water in the layer, and then enters the upper layer of spray chambers through the smoke discharge channel 7 for heat exchange, and finally discharged from the smoke discharge port 8 at the top of the top layer of spray chambers.

[0034] By arranging the vacuum phase change heat exchanger 3, the condensate water can be dynamically flashed out of the spray liquid by using the flash heat exchange principle, the liquid level is kept stable, the water balance in the spray tower 1 is realized, the dirty condensate water is replaced by distilled water, and the heat exchange can be realized while saving water resources.

[0035] But because the partition wall type heat exchanger 2 is low in cost, good in economy, and the vacuum phase change heat exchanger 3 is high in cost, so that the cost is high, therefore, if the vacuum phase change heat exchanger 3 is used to completely replace the partition wall type heat exchanger 2, the cost of the whole flue gas waste heat exchange system will be too high, and it is not suitable for popularization and use. Therefore, in the utility model, one vacuum phase change heat exchanger 3 and one or more partition wall type heat exchangers 2 are used to cooperate to extract the waste heat of low-temperature flue gas, the vacuum phase change heat exchanger 3 is used to maintain the liquid level balance in the spray tower 1, in the actual construction process, only the flash evaporation rate required is calculated according to the condensate water speed of the spray tower 1, then the vacuum phase change heat exchanger 3 with a proper size is selected, the vacuum phase change heat exchanger 3 can realize heat exchange to a certain extent while maintaining the liquid level balance in the spray tower 1, the partition wall type heat exchanger 2 is arranged to bear the heat exchange purpose of the whole flue gas waste heat exchange system, and the cost is effectively reduced.

[0036] After the flue gas waste heat exchange system is operated, the spray water liquid level in the spray tower 1 can be maintained while the waste heat is extracted, and a water treatment system does not need to be additionally arranged.

[0037] After the heat exchange system is implemented, the flue gas exhaust temperature of the power plant can be reduced to 30-15 DEG C at the lowest.

[0038] Water balance and design, operation control logic:

[0039] 1. Water balance calculation method:

[0040] The measured data in operation are:

[0041] Flue gas flow Q under standard state 烟气，干 , tower inlet flue gas moisture content d 入口 , tower outlet flue gas moisture content d 出口 , inlet flue gas enthalpy h 入口 , outlet flue gas enthalpy h 出口 ,

[0042] a tower condensate water speed = Q 烟气，干 × (d 入口 -d 出口) ;

[0043] b tower heat exchange power = Q 烟气，干 × (h 入口 -h 出口) ;

[0044] c flash evaporation rate = (tower heat exchange power-partition wall type heat exchanger heat exchange power) / latent heat of vaporization under flash evaporation temperature.

[0045] 2. Operation control strategy:

[0046] In the operation of the water balance calculation method, the flash evaporation rate is controlled in real time = the condensate water rate of the tower, so that the water balance in the tower can be controlled, that is, the liquid level of the water in the tower is dynamically maintained unchanged.

[0047] When the spray tower 1 is a single-layer single-segment spray structure, an alkali adding tank is arranged between the mixed water outlet at the bottom of the spray tower 1 and the water inlet of the vacuum phase change heat exchanger 3, and the alkali adding tank is a first alkali adding tank 9.

[0048] When the spray tower 1 is a multi-layer segmented spray structure, an alkali adding tank is arranged between the mixed water outlet at the bottom of the bottommost spray chamber and the water inlet of the vacuum phase change heat exchanger 3, and an alkali adding tank is arranged between the mixed water outlet at the bottom of each of the remaining spray chambers and the heat release side inlet of the corresponding partition type heat exchanger 2, and the alkali adding tank is a second alkali adding tank 10.

[0049] Each drain pipe 6 is provided with a drain valve. In this way, by arranging the drain pipe 6 and the drain valve, the mixed water in the high-position spray chamber can be conveniently drained into the spray chamber below.

[0050] When the spray tower 1 is a single-layer single-segment spray structure, a first conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the spray tower 1 and the water inlet of the vacuum phase change heat exchanger 3, and a second conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger 3 and the heat release side inlet of the partition type heat exchanger.

[0051] The first conveying pump is arranged between the alkali adding tank and the partition type heat exchanger 2.

[0052] When the spray tower 1 is a multi-layer segmented spray structure, a third conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the bottommost spray chamber and the water inlet of the vacuum phase change heat exchanger 3, a fourth conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of each of the remaining spray chambers and the heat release side inlet of the corresponding partition type heat exchanger 2, and a fifth conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger 3 and the spray water inlet at the upper part of the bottommost spray chamber.

[0053] The third conveying pump is arranged between the alkali adding tank and the vacuum phase change heat exchanger 3 on the connecting pipeline thereof, and the fourth conveying pump is arranged between the alkali adding tank and the partition type heat exchanger 2 on the connecting pipeline thereof.

[0054] The main process is as follows:

[0055] 1. Flue gas system process: When the spray tower 1 is a single-layer single-segment spray structure, the low-temperature flue gas enters the tower from the bottom of the spray tower 1, is cooled by the spray water sprayed from the upper part of the tower, and is then discharged from the spray tower 1.

[0056] When the spray tower 1 is a multi-layer segmented spray structure, the low-temperature flue gas enters the tower from the bottom spray chamber of the spray tower 1, and is sequentially heat-exchanged and cooled by the spray water in the N-layer spray chambers, and then is discharged from the spray tower 1;

[0057] 2. The spray water system: when the spray tower 1 is a single-layer single-segment spray structure, the spray water, after being cooled by the inter-wall heat exchanger 2, enters the upper part of the spray tower 1, and is countercurrently sprayed and heat-exchanged with the flue gas in the spray tower 1, so that the water temperature is increased after absorbing the heat release of the flue gas, and the condensed water in the flue gas is contained, and then the spray water enters the vacuum phase-change heat exchanger 3 through a conveying pump, is cooled by the vacuum phase change, and the condensed water in the flue gas is flashed into steam, the flash steam amount is controlled to be in balance with the condensation of the flue gas, that is, the liquid level balance of the spray water in the tower is achieved. The cooled spray water enters the inter-wall heat exchanger 2, and then enters the spray tower 1 after being cooled by two stages, and so on, so as to realize circulation.

[0058] When the spray tower 1 is a multi-layer segmented spray structure,

[0059] 3. The heated water system flow: the heated water is mainly divided into two gradients, and enters the heat absorption side of the vacuum phase-change heat exchanger and the heat absorption side of the inter-wall heat exchanger 2, respectively, to extract the heat of the spray tower 1.

[0060] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A spray heat exchange system capable of achieving flue gas balance, characterized in that: The device comprises a spray tower (1), a partition wall heat exchanger (2) and a vacuum phase change heat exchanger (3), a flue gas inlet (4) is arranged at the lower part of the spray tower (1), wherein the spray tower (1) is a single-layer single-section spray structure or a multi-layer section spray structure, When the spray tower (1) is a single-layer single-section spray structure, the heat release side outlet of the partition wall heat exchanger (2) is communicated with the spray water inlet of the spray tower (1), the mixed water outlet at the bottom of the spray tower (1) is communicated with the water inlet of the vacuum phase change heat exchanger (3), and the water outlet of the vacuum phase change heat exchanger (3) is communicated with the heat release side inlet of the partition wall heat exchanger (2). When the spray tower (1) is a multi-layer section spray structure, N layers of spray chambers are arranged in the spray tower (1) from bottom to top, the lower part between every two adjacent spray chambers is communicated through a liquid discharge pipe (6), a flue gas discharge channel (7) is arranged between every two adjacent spray chambers, one vacuum phase change heat exchanger (3) is arranged in the bottom spray chamber, one partition wall heat exchanger (2) is arranged in each of the remaining spray chambers, the mixed water outlet at the bottom of the bottom spray chamber is communicated with the water inlet of the vacuum phase change heat exchanger (3), the water outlet of the vacuum phase change heat exchanger (3) is communicated with the spray water inlet at the upper part of the bottom spray chamber, the heat release side outlet of each partition wall heat exchanger (2) is communicated with the spray water inlet of the corresponding spray chamber, the mixed water outlet of each spray chamber is communicated with the heat release side inlet of the corresponding partition wall heat exchanger (2), and a flue gas discharge port (8) is arranged at the top of the top spray chamber.

2. The spray heat exchange system capable of realizing flue gas balance according to claim 1, characterized in that: When the spray tower (1) is a single-layer single-section spray structure, an alkali adding box is arranged between the mixed water outlet at the bottom of the spray tower (1) and the water inlet of the vacuum phase change heat exchanger (3).

3. The spray heat exchange system capable of realizing flue gas balance according to claim 1, characterized in that: When the spray tower (1) is a multi-layer section spray structure, an alkali adding box is arranged between the mixed water outlet at the bottom of the bottom spray chamber and the water inlet of the vacuum phase change heat exchanger (3), and an alkali adding box is arranged between the mixed water outlet at the bottom of each of the remaining spray chambers and the heat release side inlet of the corresponding partition wall heat exchanger (2).

4. The spray heat exchange system capable of realizing flue gas balance according to claim 1, characterized in that: A liquid discharge valve is arranged on each liquid discharge pipe (6).

5. The spray heat exchange system capable of achieving flue gas balance according to claim 2, characterized in that: When the spray tower (1) is a single-layer single-section spray structure, a first conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the spray tower (1) and the water inlet of the vacuum phase change heat exchanger (3), and a second conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger (3) and the heat release side inlet of the partition wall heat exchanger.

6. The spray heat exchange system capable of achieving flue gas balance according to claim 5, characterized in that: The first conveying pump is arranged between the alkali adding box and the partition wall heat exchanger (2).

7. The spray heat exchange system capable of achieving flue gas balance according to claim 3, characterized in that: When the spray tower (1) is a multi-layer section spray structure, a third conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of the bottom spray chamber and the water inlet of the vacuum phase change heat exchanger (3), a fourth conveying pump is arranged on the connecting pipeline between the mixed water outlet at the bottom of each of the remaining spray chambers and the heat release side inlet of the corresponding partition wall heat exchanger (2), and a fifth conveying pump is arranged on the connecting pipeline between the water outlet of the vacuum phase change heat exchanger (3) and the spray water inlet at the upper part of the bottom spray chamber.

8. The spray heat exchange system capable of achieving flue gas balance according to claim 7, characterized in that: The third transfer pump is arranged between the alkali adding tank and the vacuum phase change heat exchanger (3) on the connecting pipeline where the third transfer pump is arranged, and the fourth transfer pump is arranged between the alkali adding tank and the partition wall type heat exchanger (2) on the connecting pipeline where the fourth transfer pump is arranged.

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