CN110425924A - A staged heat exchange spraying packed tower and flue gas treatment method for flue gas waste heat recovery - Google Patents

Abstract

The present invention provides a staged heat exchange spraying packing tower for waste heat recovery of flue gas and a flue gas treatment method, comprising the outer shell of the spraying packing tower, and the inner cavity of the outer shell of the spraying packing tower is sequentially arranged from top to bottom Spray components and packing are arranged; the side wall of the outer casing of the spray packing tower is provided with a spray circulating water inlet, a flue gas inlet and a spray circulating water outlet in sequence from top to bottom, wherein the spray circulating water inlet It communicates with the spray assembly; the flue gas inlet is arranged under the packing; the spray circulating water outlet is arranged under the flue gas inlet; the top of the outer casing of the spray packing tower is provided with a flue gas outlet; The temperature drop in the process is relatively large. The flue gas temperature in the first stage is high and the heat transfer temperature difference is large. The flue gas temperature in the latter stage is low and the heat transfer temperature difference is small. The heat transfer characteristics of the two stages are different. Combined with the heat, the heat exchange process is divided into two stages for processing, which has the advantages of both the spray tower and the packed tower.

Description

A staged heat exchange spraying packed tower and flue gas treatment method for flue gas waste heat recovery

technical field

The invention belongs to the field of flue gas waste heat recovery, in particular to a stage-by-stage heat exchange spraying packing tower for flue gas waste heat recovery and a flue gas treatment method.

Background technique

At present, there are two main methods of direct heat exchange equipment used for flue gas waste heat recovery: empty tower spray heat exchange and packed tower heat exchange.

The empty tower spray heat exchange uses nozzles to atomize the circulating water into extremely small droplets, which greatly increases the gas-liquid two-phase contact area, completes heat transfer and mass transfer in an instant, and achieves the purpose of enhancing heat exchange. Stable contact heat exchange can be realized under very small temperature difference, spray cooling is adopted without packing, the running resistance is small, and the investment is small; the packed tower can eliminate the influence of the drift and eddy current of the flue gas flow in the spray heat exchange of the empty tower, and avoid the resulting The vibration of the tower body will increase the service life of the tower, enhance the safety and reliability of the tower, and improve the stability of gas-liquid heat exchange, but the investment cost of packing will also increase significantly.

Contents of the invention

The object of the present invention is to provide a stage-by-stage heat exchange spraying packing tower and a flue gas treatment method for recovery of waste heat from flue gas, which solves the shortcomings of the two existing methods of waste heat recovery from flue gas.

In order to achieve the above object, the technical scheme adopted in the present invention is:

The present invention provides a staged heat exchange spraying packing tower for waste heat recovery of flue gas, comprising a spraying packing tower shell, and spraying components are sequentially arranged in the inner cavity of the spraying packing tower shell from top to bottom and packing; the side wall of the outer casing of the spray packing tower is provided with a spray circulating water inlet, a flue gas inlet and a spray circulating water outlet in sequence from top to bottom, wherein the spray circulating water inlet communicates with the spray assembly The flue gas inlet is arranged under the filler; the spray circulating water outlet is arranged under the flue gas inlet; the top of the outer casing of the spray packed tower is provided with a flue gas outlet.

Preferably, a liquid distributor is also arranged in the inner cavity of the outer casing of the spray packed tower, and the liquid distributor is arranged above the packing.

Preferably, a spray heat exchange space is formed between the liquid distributor and the spray assembly.

Preferably, the packing is structured packing.

Preferably, the lower end of the filler is provided with a filler support plate.

Preferably, the packing support plate and the outer casing of the spray packed tower are integrally structured.

Preferably, a manhole is provided on the upper side wall of the outer shell of the spray packed tower, and the manhole is arranged above the spray assembly.

A method for treating flue gas using the staged heat exchange spraying packed tower for recovery of waste heat from flue gas, comprising the following steps:

The flue gas enters the cylinder from the flue gas inlet, passes through the packing and spray components in turn, and finally is discharged from the flue gas outlet;

The spray circulating water enters the cylinder body from the spray circulating water inlet, passes through the spray assembly and packing in turn, and finally discharges from the spray circulating water outlet;

The flue gas first exchanges heat with the spray circulating water on the packing for the first time, then enters the spray heat exchange space, and performs the second heat exchange with the spray circulating water.

Compared with prior art, the beneficial effect of the present invention is:

The present invention provides a stage-by-stage heat exchange spraying packing tower and flue gas treatment method for flue gas waste heat recovery. Due to the large temperature drop in the flue gas condensation process, the flue gas temperature in the first stage is high and the heat transfer temperature difference is large. In the first stage, the flue gas temperature is low, the heat transfer temperature difference is small, and the heat transfer characteristics of the two stages are different. The empty tower spray heat transfer and the packed tower heat transfer are combined, and the heat transfer process is divided into two stages for processing, which has both the spray tower and the packed tower. The advantages of the packed tower: In the first stage of flue gas condensation, the packed layer is used for heat exchange, which eliminates the influence of the drift and eddy flow of the flue gas flow in the empty tower spray heat exchange, and avoids the vibration of the tower body caused by it, thereby increasing the use of the tower life, enhance the safety and reliability of the tower, and improve the stability of gas-liquid heat exchange; spray heat exchange is used in the second stage of flue gas condensation, which greatly increases the contact area of the gas-liquid two-phase to achieve the purpose of strengthening heat exchange, making The flue gas and circulating water can realize stable contact heat exchange under a small temperature difference, and the running resistance is small, which reduces investment.

Further, the liquid distributor can evenly distribute the spray circulating water.

Description of drawings

Fig. 1 is a schematic structural view of the spray packed tower involved in the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 1, a staged heat exchange spraying packed tower for waste heat recovery of flue gas provided by the present invention includes a spraying packed tower shell 1, a spraying circulating water inlet 2, a liquid distributor 3, a spraying cycle Water outlet 4, flue gas inlet 7, packing 8, spray assembly 9, manhole 10, flue gas outlet 11, packing support plate 13 and spray heat exchange space 14, wherein, the shell of the spray packed tower includes A circular cylinder and an upper oval head, the upper oval head cover is mounted on the upper end of the circular cylinder; the inner cavity of the circular cylinder is arranged in sequence from top to bottom with a spray assembly 9, a liquid distribution 3 and filler 8; the side wall of the circular cylinder is provided with a spray circulating water inlet 2, a flue gas inlet 7 and a spray circulating water outlet 4 sequentially from top to bottom, wherein the spray circulating water inlet 2 It communicates with the spray assembly 9; the flue gas inlet 7 is arranged under the packing 8; the spray circulating water outlet 4 is arranged under the flue gas inlet 7.

A spray heat exchange space 14 is formed between the liquid distributor 3 and the spray assembly 9 .

The lower end of the filler 8 is provided with a filler support plate 13 .

The packing 8 is structured packing, and the structured packing includes grid packing, corrugated packing and pulse packing.

The packing support plate 13 and the outer casing 1 of the spray packing tower are of an integral structure. The packing 8 is placed on the packing support plate 13 .

A manhole 10 is also provided on the circular cylinder, and the manhole 10 is arranged above the spray assembly 9 to facilitate the installation, inspection and maintenance of the internal equipment components of the main body of the spray packed tower.

A flue gas outlet 11 is opened on the top of the upper oval head.

The working principle of the present invention is:

The flue gas enters the cylinder from the flue gas inlet 7 arranged at the bottom of the cylinder, passes through the filler 8, the liquid distributor 3, and the spray assembly 9 in sequence, and finally is discharged from the flue gas outlet 11 arranged on the upper oval head;

The spray circulating water enters the cylinder from the spray circulating water inlet 2 set on the upper part of the cylinder, passes through the spray assembly 9, the liquid distributor 3 and the packing 8 in sequence, and finally flows through the spray circulating water outlet 4 set at the bottom of the cylinder discharge;

The flue gas first exchanges heat with the spraying circulating water on the packing 8 for the first time, and then enters the spraying heat exchange space 14, and performs the second heat exchange with the spraying circulating water.

The liquid distributor 3 is used to realize the uniform distribution of the spray circulating water.

The present invention has the following advantages:

1. The staged heat exchange spraying packed tower for waste heat recovery of flue gas provided by the present invention, according to the characteristics of large heat exchange temperature difference in the previous stage of the flue gas condensation process and small heat exchange temperature difference in the latter stage, the empty tower is sprayed for heat exchange Combined with the heat exchange of the packed tower, the heat exchange process is divided into two stages for treatment, which has the advantages of both the spray tower and the packed tower.

2. The staged heat exchange spraying packing tower for flue gas waste heat recovery provided by the present invention adopts packing layer heat exchange in the first stage of flue gas condensation to eliminate the influence of drift and eddy flow of flue gas flow in empty tower spraying heat exchange , to avoid the resulting vibration of the tower body, thereby increasing the service life of the tower, enhancing the safety and reliability of the tower, and improving the stability of gas-liquid heat exchange.

3. The staged heat exchange spraying packing tower for waste heat recovery of flue gas provided by the present invention adopts spraying heat exchange in the second stage of flue gas condensation, which greatly increases the contact area of gas-liquid two-phase and achieves the purpose of strengthening heat exchange , so that the flue gas and circulating water can achieve stable contact heat exchange under a small temperature difference, the running resistance is small, and the investment is reduced.

Claims (8)

1. A staged heat exchange spraying packed tower for flue gas waste heat recovery, characterized in that it comprises a sprayed packed tower shell (1), and the inner cavity of the sprayed packed tower shell (1) is from top to bottom Spray components (9) and fillers (8) are arranged in sequence from bottom to bottom; the side wall of the outer shell (1) of the spray packed tower is provided with spray circulating water inlet (2), flue gas inlet (7) and spray circulating water outlet (4), wherein the spray circulating water inlet (2) communicates with the spray assembly (9); the flue gas inlet (7) is arranged below the filler (8); the spray The circulating water outlet (4) is arranged below the flue gas inlet (7); the top of the spray packed tower shell (1) is provided with a flue gas outlet (11). 2. A stage-by-stage heat exchange spraying packed tower for flue gas waste heat recovery according to claim 1, characterized in that a liquid distributor is also arranged in the inner cavity of the outer shell (1) of the sprayed packed tower (3), the liquid distributor (3) is arranged above the filler (8). 3. A staged heat exchange spraying packed tower for flue gas waste heat recovery according to claim 1, characterized in that a spray heat exchange is formed between the liquid distributor (3) and the spray assembly (9) space (14). 4. A staged heat exchange spraying packed tower for recovery of flue gas waste heat according to claim 1, characterized in that the packing (8) is structured packing. 5. A staged heat exchange spraying packed tower for waste heat recovery of flue gas according to claim 4, characterized in that a packing support plate (13) is provided at the lower end of the packing (8). 6. A staged heat exchange spraying packed tower for waste heat recovery of flue gas according to claim 5, characterized in that the packing support plate (13) and the outer casing (1) of the spraying packed tower are of an integrated structure. 7. A staged heat exchange spraying packed tower for waste heat recovery of flue gas according to claim 1, characterized in that, manholes ( 10), the manhole (10) is arranged above the spray assembly (9). 8. A method for treating flue gas in a staged heat exchange spraying packed tower utilizing the flue gas waste heat recovery described in any one of claims 1-7, characterized in that it comprises the following steps: The flue gas enters the barrel from the flue gas inlet (7), passes through the filler (8) and the spray assembly (9) in sequence, and finally is discharged from the flue gas outlet (11); The spray circulating water enters the cylinder from the spray circulating water inlet (2), passes through the spray assembly (9) and packing (8) in turn, and finally discharges from the spray circulating water outlet (4); The flue gas first exchanges heat with the spray circulating water on the packing (8) for the first time, and then enters the spray heat exchange space (14) to perform the second heat exchange with the spray circulating water.