CN111720848A - A system for reducing flue gas temperature at the outlet of wet desulfurization absorption tower - Google Patents

Abstract

The invention relates to the technical field of industrial flue gas pollution control, in particular to a system for reducing the flue gas temperature at the outlet of a wet desulfurization absorption tower. The system of the invention includes a cooling water tower arranged outside the desulfurization tower cylinder, and several cooling modules arranged inside the desulfurization tower cylinder and connected with the cooling water tower; the cooling modules are arranged in the uppermost spray layer in the desulfurization tower and inside the tower Between the mist eliminators and below the other spray layers; the cooling module includes a number of cooling water pipes, and the cooling water pipes are connected with the cylinder of the desulfurization tower through flanges; one end of the cooling water pipe passes through the cooling module inlet pipe and the cooling water tower. The water outlet of the cooling module is connected to the water outlet, and the other end is connected to the water inlet of the cooling water tower through the water outlet pipe of the cooling module. The invention can not only effectively reduce the flue gas temperature after the absorption tower, but also reduce the droplet carrying amount of the flue gas at the outlet of the desulfurization tower, and has the advantages of small transformation engineering quantity, simple system, low investment cost and large adaptability.

Description

A system for reducing flue gas temperature at the outlet of wet desulfurization absorption tower

technical field

The invention relates to the technical field of industrial flue gas pollution control, in particular to a system for reducing the flue gas temperature at the outlet of a wet desulfurization absorption tower.

Background technique

As we all know, wet desulfurization technology occupies a dominant position in the flue gas desulfurization technology of domestic industrial coal-fired boilers. However, in industrial coal-fired boilers using wet desulfurization technology, the wet saturated flue gas at the outlet of the absorption tower is cooled during the process of being discharged through the chimney, resulting in supersaturated condensation and white plumes. In this regard, due to various factors, it is necessary to control the temperature and moisture content of the flue gas at the outlet of the absorption tower of the industrial coal-fired boiler, and strictly control the emission value to achieve whitening of the plume.

In order to achieve the control of white plume at the chimney outlet, the current mainstream technology is to first condense and cool the flue gas at the outlet of the absorption tower, and then heat it up, and finally achieve whitening. Condensation and cooling is a very necessary link in the process of plume control. On the one hand, it achieves the reduction of the moisture content of the flue gas and achieves the purpose of "whitening"; The droplets can absorb a small amount of dust, SO ₂ , SO ₃ and other pollutant particles to further remove pollutants. At present, the commonly used flue gas condensation technologies are the gas-liquid condensation tube heat exchanger after the absorption tower and the liquid-liquid slurry plate heat exchanger set in the slurry circulation pipeline outside the absorption tower. The former has a lot of performance, but the amount of reconstruction work is very large, and it has high requirements for the space between the absorption tower and the chimney, because it is usually arranged on the clean flue between the absorption tower and the chimney, and the gas-liquid condenser The flow rate in the heat exchanger is much lower than that of the flue gas in the clean flue. The location of the gas-liquid condensing tube heat exchanger often requires a larger flue cross-section; and in order to prevent the flue gas from affecting the condensate To produce secondary carryover, it is often necessary to add a flue demister after the gas-liquid condenser tube heat exchanger, which increases the complexity and water consumption of the desulfurization system. The latter has less operating performance, and the liquid-liquid slurry plate heat exchanger operates in poor operating conditions, which is easy to cause blockage and wear of the heat exchanger body, and once the heat exchanger body fails, its corresponding slurry circulation needs to be shut down. The pump is overhauled, which puts great pressure on the operation of the desulfurization system.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides a system for reducing the flue gas temperature at the outlet of the wet desulfurization absorption tower, which can not only effectively reduce the flue gas temperature after the absorption tower, reduce the moisture content of the flue gas, and prevent the condensate from being absorbed by the flue gas The absorption tower is taken out, and it has the function of a certain mist eliminator, which can reduce the droplet carrying amount of the flue gas at the outlet of the desulfurization tower; the system has a small amount of renovation work, a simple system, low investment cost, and large adaptability.

The present invention is achieved through the following technical solutions:

A system for reducing flue gas temperature at the outlet of a wet desulfurization absorption tower, comprising a cooling water tower arranged outside the desulfurization tower cylinder, and several cooling modules arranged inside the desulfurization tower and connected to the cooling water tower; the cooling modules are arranged in the Between the uppermost spray layer in the desulfurization tower and the mist eliminator in the tower, and below the other spray layers.

Preferably, the cooling module includes a plurality of cooling water pipes, and the cooling water pipes are connected with the shell of the desulfurization tower through flanges; one end of the cooling water pipe is connected with the water outlet of the cooling water tower through the cooling module inlet pipe, and the other end is connected through the cooling module outlet pipe. Connect with the water inlet of the cooling water tower.

Further, the diameter of the cooling water pipe ranges from φ20mm to φ500mm.

Further, the cooling water pipe is made of duplex stainless steel.

Further, the water inlet pipes of each cooling water pipe are respectively provided with valves.

Further, the cooling water pipes are arranged in one layer and adopt a straight tube bundle type or a serpentine tube bundle type.

Further, the plurality of cooling water pipes are arranged in upper and lower layers, and the plurality of cooling water pipes in each layer are of straight tube bundle type, and the upper and lower layers are laid in a staggered manner.

Preferably, the water inlet pipeline of the cooling module is connected with a plurality of cooling modules through a plurality of connecting branch pipes; the connecting branch pipes are all provided with water inlet control valves of the cooling module.

Preferably, pressure and temperature test elements are provided on the cooling module water inlet pipe and the cooling module water outlet pipe.

Preferably, a cooling water circulating pump is installed on the water inlet pipe of the cooling module; and a slurry circulating pump is respectively installed on the connecting pipes of the slurry pool and the spray layer.

Compared with the prior art, the present invention has the following beneficial technical effects:

In the present invention, a cooling module is arranged between the uppermost spray layer in the desulfurization tower and the mist eliminator in the tower and under each spray layer, so that the cooling module directly contacts the flue gas in the tower for heat exchange, so as to realize the cooling effect in the tower. The flue gas is cooled, the saturated wet flue gas is condensed, and when the condensate passes through the demister in the tower together with the flue gas, it is directly intercepted and enters the absorption tower, thereby reducing the desulfurization slurry temperature and the flue gas temperature in the desulfurization tower during the desulfurization operation. Then reduce the flue gas temperature and slurry temperature of the desulfurization tower; in the process of flue gas cooling in the desulfurization tower, soluble salts, sulfuric acid mist, organic matter and other substances in the flue gas are precipitated with the condensation of water vapor in the flue gas, which can effectively alleviate the The colored plume at the chimney outlet is discharged, and the generation of gypsum rain from the chimney is avoided; at the same time, the low-temperature slurry can reduce the amount of flue gas in the tower, improve the liquid-gas ratio of the desulfurization device, and improve the desulfurization efficiency and synergistic dust removal effect. Compared with the existing flue The condensing heat exchanger has small new power consumption, small amount of renovation work, small investment, reliable operation, simple maintenance and repair; moreover, it can be flexibly controlled by controlling the cooling water volume of the slurry cooling module according to the different ambient temperature and the temperature of the cooling water in the season. Adjust the temperature of the desulfurization slurry.

Further, the cooling water pipes in the cooling module are made of duplex stainless steel and above, so as to ensure that the cooling water pipes are resistant to corrosion, erosion and wear, have good mechanical properties, and have high strength.

Further, the method of setting valves for independent control at the inlet pipe of each cooling water pipe is adopted to ensure that the cooling water pipe can be de-coupled separately without affecting the normal operation of the entire cooling device in the event of failure or damage.

Further, by disposing pressure and temperature test elements respectively on the water inlet pipe of the cooling module and the water outlet pipe of the cooling module, the operating pressure and temperature of the cooling water pipe can be effectively monitored.

Description of drawings

FIG. 1 is a schematic structural diagram of the system of the present invention.

FIG. 2 is a schematic structural diagram of the cooling module according to Embodiment 1 of the present invention.

FIG. 3 is a schematic structural diagram of the cooling module according to Embodiment 2 of the present invention.

FIG. 4 is a schematic structural diagram of the cooling module according to Embodiment 3 of the present invention.

In the picture: 1- cooling water tower, 2- flue gas inlet of desulfurization tower, 3- slurry pool, 41- cooling water circulation pump, 42- slurry circulation pump, 5- cooling module, 51- cooling water pipe, 6- desulfurization tower flue gas outlet , 7- cooling module inlet pipe, 8- spray layer, 9- cooling module inlet control valve, 10- cooling module outlet pipe, 11- desulfurization tower cylinder, 12- demister.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings, which are to explain rather than limit the present invention.

Example 1

A system for reducing the flue gas temperature at the outlet of the wet desulfurization absorption tower of the present invention, as shown in FIG. 1 , includes a desulfurization tower cylinder 11, a mist eliminator 12, a desulfurization tower flue gas inlet 2, a desulfurization tower flue gas outlet 6, and a slurry pool. 3. Spray layer 8, slurry circulation pump 42, cooling module 5, cooling water pipe 51, cooling water tower 1, cooling water circulation pump 41, cooling module inlet pipe 7, cooling module inlet control valve 9, cooling module outlet pipe 10;

The desulfurization slurry in the desulfurization tower cylinder 11 enters the multi-layer spray layer 8 through the slurry circulation pump 42 and then falls from top to bottom, and the flue gas enters the desulfurization tower cylinder 11 from bottom to top from the flue gas inlet 2 of the desulfurization tower. It is cooled by countercurrent contact with the spray slurry, and further heat exchange and cooling are carried out through several cooling water pipes 51 in the multi-layer cooling module 5. During this process, the wet saturated flue gas becomes supersaturated wet flue gas, and the water in the flue gas Substances such as steam, soluble salt, sulfuric acid mist, and organic matter are condensed and precipitated from the flue gas, which relieves the generation of colored plumes and gypsum rain at the chimney outlet, and the treated flue gas is discharged from the desulfurization tower flue gas outlet 6 through the demister 12;

The high-temperature cooling water after heat exchange enters the cooling water tower 1 through the cooling module outlet pipe 10 for cooling, and the cooled low-temperature cooling water enters the cooling module 5 through the cooling module water inlet pipe 7 and the cooling water circulation pump 41 to exchange heat with the desulfurization slurry and flue gas;

Among them, the cooling water pipe 51 in the cooling module 5 adopts a straight tube bundle type, as shown in FIG. 2 , which is simple to process and easy to maintain.

According to the different cooling water sources of different power plants, the cooling water source of the present invention may adopt circulating water, river water or sea water in the cooling water tower 1 .

Example 2

The present invention is a system for reducing the flue gas temperature at the outlet of the wet desulfurization absorption tower. As shown in FIG. 3 , the cooling water pipe 51 in the cooling module 5 adopts a serpentine tube bundle type, which increases the working area of the cooling water pipe 51 and improves the cooling efficiency. The rest of the structure is the same as described in Example 1.

Example 3

The present invention is a system for reducing the flue gas temperature at the outlet of the wet desulfurization absorption tower. If the flue gas temperature at the outlet is high, the cooling module 5 as shown in FIG. 4 can be used. The cooling water pipes 51 in the cooling module 5 in FIG. 4 are staggered up and down. The laid straight tube bundle type, the rest of the structure is the same as described in Example 1.

The above-mentioned embodiments 1-3 are the preferred embodiments of the cooling module 5 of the present invention, and are not intended to limit the present invention. The type of the cooling module 5 can be modified, improved or equivalently replaced within the principles of the present invention.

Claims (10)

1. A system for reducing the smoke temperature at the outlet of a wet desulphurization absorption tower is characterized by comprising a cooling tower (1) arranged outside a desulphurization tower cylinder (11) and a plurality of cooling modules (5) arranged in the desulphurization tower cylinder (11) and connected with the cooling tower (1); the cooling module (5) is arranged between the uppermost layer spraying layer (8) in the desulfurizing tower and the demister (12) in the tower, and the rest layers are arranged below the spraying layer (8).

2. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 1, wherein the cooling module (5) comprises a plurality of cooling water pipes (51), and the cooling water pipes (51) are connected with the desulphurization tower cylinder (11) through flanges; one end of the cooling water pipe (51) is connected with the water outlet of the cooling water tower (1) through a cooling module water inlet pipeline (7), and the other end of the cooling water pipe is connected with the water inlet of the cooling water tower (1) through a cooling module water outlet pipeline (10).

3. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 2, wherein the cooling water pipe (51) has a pipe diameter ranging from phi 20mm to phi 500 mm.

4. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 2, wherein the cooling water pipe (51) is made of duplex stainless steel.

5. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 2, wherein the inlet pipeline of each cooling water pipe (51) is provided with a valve.

6. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 2, wherein the cooling water pipes (51) are arranged in a layer and adopt a straight pipe bundle type or a serpentine pipe bundle type.

7. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 2, wherein the plurality of cooling water pipes (51) are arranged in an upper layer and a lower layer, the plurality of cooling water pipes (51) in each layer are in a straight pipe bundle type, and the upper layer and the lower layer are alternately laid.

8. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 1, wherein the cooling module water inlet pipeline (7) is connected with a plurality of cooling modules (5) through a plurality of connecting branch pipes; and the connecting branch pipes are provided with cooling module water inlet control valves (9).

9. The system for reducing the outlet smoke temperature of the wet desulphurization absorption tower according to claim 1, wherein the inlet pipeline (7) of the cooling module and the outlet pipeline (10) of the cooling module are provided with pressure and temperature test elements.

10. The system for reducing the smoke temperature at the outlet of the wet desulphurization absorption tower according to claim 1, wherein a cooling water circulating pump (41) is installed on the cooling module water inlet pipeline (7); and a slurry circulating pump (42) is respectively arranged on the connecting pipeline of the slurry pool (3) and the spraying layer (8).

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