CN211651283U - A device for deep recovery of waste heat from boiler flue gas and air humidification - Google Patents

Abstract

The utility model provides a device for realizing deep recovery of boiler flue gas waste heat and air humidification, which reduces the temperature of boiler exhaust gas to below the water dew point, improves energy utilization efficiency, saves natural gas consumption, and the recovered waste heat can also be used as external The heat source of heat users has significant economic benefits; through air humidification and flue gas recirculation, the oxygen concentration of the combustion-supporting air entering the boiler is reduced, the combustion temperature is lowered, and the purpose of reducing the NOx emission concentration is achieved. In addition, flue gas recirculation can provide more heat for the combustion-supporting air humidification process and increase the air humidification capacity; because the temperature of the boiler exhaust flue gas is lowered to below the water dew point, most of the water vapor in the flue gas condenses, which can be recovered in the flue gas. The purpose of water vapor is to reduce water consumption and alleviate the visual pollution of white smoke plumes.

Description

A device for deep recovery of waste heat from boiler flue gas and air humidification

technical field

The utility model belongs to the field of energy saving and emission reduction of thermal power generation, in particular to a device for realizing deep recovery of waste heat of boiler flue gas and air humidification.

Background technique

Natural gas flue gas contains a large amount of water vapor, and the latent heat of vaporization of natural gas accounts for 10% to 11% of the low-level calorific value of natural gas. In addition, the water vapor in the flue gas is directly discharged into the atmosphere, which not only causes water loss, but also forms a white smoke plume phenomenon, causing landscape pollution. The deep recycling of flue gas waste heat, including the latent heat of condensation of water vapor, is of great significance for saving energy and reducing pollutant emissions. The deep utilization technology of flue gas waste heat is to add a condensing heat exchanger in the tail flue. The flue gas exchanges heat with the intermediate water efficiently in the heat exchanger. The flue gas is rapidly cooled and condensed. After removing most of the water vapor, it is sent to the chimney . The intermediate water that exchanges heat with the flue gas is heated and enters the absorption heat pump to release heat, which can realize the recovery and transfer of the low-temperature waste heat of the flue gas to the urban heat network and other heat users.

The NOx generation concentration of natural gas in the boiler combustion process is mainly affected by temperature, and the thermal NOx emission increases exponentially with the increase of temperature. After injecting water vapor or water into the combustion air of the boiler, the generation of thermal NOx during the combustion process can be reduced. In addition, the NOx generated by natural gas during the combustion process of the boiler can also be reduced by the flue gas recirculation technology. The flue gas recirculation technology is to extract part of the cooled flue gas, mix it with the combustion air entering the boiler and send it to the combustion system, which can reduce the The effect of oxygen concentration and combustion area temperature to achieve the purpose of reducing the amount of thermal NOx generation.

However, the conventional flue gas recirculation technology has the disadvantage that the effect of reducing the amount of thermal NOx generation is not satisfactory.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide a device for realizing deep recovery of boiler flue gas waste heat and air humidification, which solves the deficiencies in the prior art.

In order to achieve the above-mentioned purpose, the technical scheme that the utility model adopts is:

The utility model provides a device for realizing deep recovery of boiler flue gas waste heat and air humidification, comprising a boiler and a waste heat recovery tower, wherein the boiler is provided with a natural gas inlet, and the flue gas outlet on the boiler is respectively connected with the waste heat recovery tower. Upper tower and lower tower connection;

The upper tower of the waste heat recovery tower is provided with a smoke outlet;

A high temperature humidified flue gas outlet is arranged on the lower tower of the waste heat recovery tower, and the high temperature humidified flue gas outlet is connected with the inlet of the boiler.

Preferably, a first induced draft fan is arranged between the outlet of the boiler and the upper tower of the waste heat recovery tower.

Preferably, a second induced draft fan is arranged between the outlet of the boiler and the lower tower of the waste heat recovery tower.

Preferably, an upper tower mist eliminator, an upper tower cloth liquid layer, an upper tower packing layer and an upper tower liquid storage layer are sequentially arranged in the upper tower inner cavity of the waste heat recovery tower from top to bottom, wherein the waste heat recovery The smoke exhaust port on the upper tower of the tower is arranged above the mist eliminator of the upper tower; the upper tower cloth liquid layer is provided with an intermediate water inlet; the upper tower liquid storage layer is provided with an intermediate water outlet, and the intermediate water The water outlet is connected to the intermediate water inlet via the heat pump.

Preferably, the flue gas inlet on the upper tower of the waste heat recovery tower is arranged between the upper tower liquid storage layer and the upper tower packing layer.

Preferably, the upper tower of the waste heat recovery tower is further provided with a first overflow port, and the first overflow port is arranged above the liquid storage layer of the upper tower; the bottom of the liquid storage layer of the upper tower is provided with an intermediary A water outlet, the intermediate water outlet communicates with the lower tower of the waste heat recovery tower.

Preferably, a first valve and a first water pump are sequentially arranged between the intermediate water outlet on the liquid storage layer of the upper tower and the heat pump.

Preferably, the inner cavity of the lower tower of the waste heat recovery tower is sequentially arranged with a lower tower cloth layer, a lower tower packing layer and a lower tower liquid storage layer from top to bottom; The high-temperature humidification flue gas outlet of the lower tower is arranged above the lower tower cloth liquid layer; the lower tower cloth liquid layer is provided with an intermediate water inlet, and the intermediate water inlet is communicated with the upper tower of the waste heat recovery tower; the lower tower liquid storage layer An intermediate water outlet is provided, and the intermediate water outlet communicates with the upper tower of the waste heat recovery tower; the flue gas inlet and air inlet on the lower tower of the waste heat recovery tower are arranged between the lower tower liquid storage layer and the lower tower packing layer.

Preferably, the lower tower of the waste heat recovery tower is further provided with a second overflow port, and the second overflow port is arranged above the liquid storage layer of the lower tower.

Preferably, a second valve and a second water pump are sequentially arranged between the intermediate water outlet provided on the liquid storage layer of the lower tower and the upper tower of the waste heat recovery tower.

Compared with the prior art, the beneficial effects of the present utility model are:

The invention provides a device for realizing deep recovery of boiler flue gas waste heat and air humidification, which reduces the oxygen concentration of combustion-supporting air entering the boiler through air humidification and flue gas recirculation, reduces combustion temperature, and achieves the purpose of reducing NOx emission concentration; In addition, flue gas recirculation can provide more heat for the combustion-supporting air humidification process and increase the amount of air humidification; because the temperature of the boiler exhaust flue gas is lowered to below the water dew point, most of the water vapor in the flue gas condenses, which can be recovered in the flue gas. The purpose of water vapor is to reduce water consumption and alleviate the visual pollution of white smoke plumes. At the same time, it improves energy utilization efficiency and saves natural gas consumption. The recovered waste heat can also be used as a heat source for external heat users, which has significant economic benefits.

To sum up, the deep recovery process of flue gas waste heat is integrated with air humidification, flue gas recirculation, and flue gas exhaust processes in one device. The device has a compact structure and is easy to process, and makes full use of the height difference of the intermediate water to achieve gravity liquid distribution. Low energy consumption.

Description of drawings

FIG. 1 is a schematic diagram of the structure of the device involved in the present invention.

Detailed ways

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

As shown in Figure 1, the utility model provides a device for deep recovery of boiler flue gas waste heat and air humidification, including boiler 1, heat pump 2, waste heat recovery tower 3, upper tower packing layer 4, upper tower cloth liquid layer 5 , the upper tower mist eliminator 6, the chimney 7, the first valve 8, the first water pump 9, the first overflow port 10, the upper tower liquid storage tank 11, the lower tower packing layer 12, the lower tower cloth liquid layer 13, the second The valve 14, the second water pump 15, the second overflow port 16, the lower tower liquid storage tank 17, the air duct demister 18, the first induced draft fan 19, the second induced draft fan 20, the blower 21 and the damper 22, among which, the boiler 1 is provided with a natural gas inlet, and the flue gas outlet of the boiler 1 is connected to the first induced draft fan 19 and the second induced draft fan 20 respectively.

The outlet of the first induced draft fan 19 is connected to the upper tower of the waste heat recovery tower 3 . The top of the upper tower of the waste heat recovery tower 3 is provided with a smoke outlet, and the smoke outlet communicates with the chimney 7 .

The upper tower of the waste heat recovery tower 3 is provided with an intermediate water outlet, and the intermediate water outlet is sequentially connected to the heat pump 2 through the first valve 8 and the first water pump 9, and the intermediate water outlet of the heat pump 2 is connected to the upper part of the waste heat recovery tower 3. Intermediary water inlet connections for tower settings.

The outlet of the second induced draft fan 20 is connected to the lower tower of the waste heat recovery tower through the damper 22 .

The lower tower of the waste heat recovery tower 3 is provided with an air inlet; the high temperature humidified flue gas outlet arranged on the lower tower of the waste heat recovery tower 3 is connected to the inlet of the boiler 1 through the air duct demister 18 .

An intermediate water outlet is provided on the lower tower of the waste heat recovery tower 3 , and the intermediate water outlet is connected to the intermediate water inlet on the upper tower of the waste heat recovery tower 3 through the second valve 14 and the second water pump 15 in sequence.

The lower tower of the waste heat recovery tower is provided with an intermediate water inlet, and the intermediate water inlet is connected to the upper tower of the waste heat recovery tower 3 .

The upper tower inner cavity of the waste heat recovery tower is sequentially arranged with an upper tower mist eliminator 6, an upper tower cloth liquid layer 5, an upper tower packing layer and an upper tower liquid storage layer 11 from top to bottom.

The exhaust port on the upper tower of the waste heat recovery tower 3 is arranged above the mist eliminator 6 in the upper tower.

The intermediate water inlet on the upper tower of the waste heat recovery tower 3 is arranged on the upper tower cloth liquid layer 5 .

The intermediate water outlet on the upper tower of the waste heat recovery tower 3 is arranged on the liquid storage layer 11 of the upper tower.

The flue gas inlet on the upper tower of the waste heat recovery tower 3 is arranged between the upper tower liquid storage layer 11 and the upper tower packing layer 4 .

The upper tower of the waste heat recovery tower 3 is also provided with a first overflow port 10 , and the first overflow port 10 is arranged above the liquid storage layer 11 of the upper tower.

The bottom of the upper tower liquid storage layer 11 is provided with an intermediate water outlet, and the intermediate water outlet is communicated with the lower tower of the waste heat recovery tower 3 .

In the inner cavity of the lower tower of the waste heat recovery tower 3, the lower tower liquid layer 13, the lower tower packing layer 12 and the lower tower liquid storage layer 17 are sequentially arranged from top to bottom.

The high temperature humidified flue gas outlet on the lower tower of the waste heat recovery tower 3 is arranged above the lower tower cloth liquid layer.

The intermediate water inlet on the lower tower of the waste heat recovery tower 3 is arranged on the lower tower cloth liquid layer 13 ; the intermediate water outlet at the bottom of the upper tower liquid storage layer 11 communicates with the lower tower cloth liquid layer 13 .

The intermediate water outlet on the lower tower of the waste heat recovery tower 3 is arranged on the liquid storage layer 17 of the lower tower.

The flue gas inlet and the air inlet on the lower tower of the waste heat recovery tower 3 are both arranged between the lower tower liquid storage layer 17 and the lower tower packing layer 12 .

A second overflow port 16 is also provided on the lower tower of the waste heat recovery tower 3 , and the second overflow port 16 is arranged above the liquid storage layer 17 of the lower tower.

The workflow of the system is:

After the natural gas is combusted with the humidified air in the boiler 1 to release heat, the boiler flue gas formed is divided into two paths. The first path is sent to the upper tower of the waste heat recovery tower 3 by the first induced draft fan 19, and then passes through the upper tower packing layer 4 and the upper tower in turn. After the liquid distribution layer 5 and the upper tower mist eliminator 6, the direct contact heat and mass transfer process is carried out with the low-temperature intermediate water sprayed from the upper tower liquid layer 5. After the boiler flue gas is cooled and dehumidified, it is sent to the waste heat recovery device. The chimney 7 above the equipment is discharged into the atmosphere.

The low-temperature intermediate water is sprayed from the upper tower cloth liquid layer 5 to the upper tower packing layer 4, and undergoes a direct contact heat and mass transfer process with the boiler flue gas.

The intermediate water is drawn from the liquid storage tank 11 of the upper tower, and sent to the heat pump 2 after passing through the first valve 8 and the first water pump 9 .

A first overflow port 10 is arranged above the liquid storage tank 11 of the upper tower.

The second route of the boiler flue gas passes through the second induced draft fan 20 and the damper 22, and is sent to the lower tower of the waste heat recovery tower 3; the combustion-supporting air of the boiler 1 passes through the blower 21 and is sent to the lower tower of the waste heat recovery tower 3; In the lower tower of the waste heat recovery tower 3, the gas passes through the lower tower packing layer 12 and the lower tower cloth liquid layer 13 in turn, and conducts a direct contact heat and mass transfer process with the high-temperature intermediate water sprayed from the lower tower cloth liquid layer 13, and the combustion-supporting air After warming up and humidifying, it leaves the waste heat recovery tower 3 and goes down the tower, passes through the air duct mist eliminator 18, and is sent to the boiler 1.

The intermediate water flowing out from the upper tower liquid storage tank 11 of the waste heat recovery tower 3 is sprayed from the lower tower cloth liquid layer 13 to the lower tower packing layer 12, and conducts a direct contact heat and mass transfer process with combustion-supporting air and part of the boiler flue gas, The intermediate water falls into the lower tower liquid storage tank 17 after cooling down.

The intermediate water is drawn from the liquid storage tank 17 in the lower tower, passes through the second valve 14 and the second water pump 15, and is sent into the liquid layer 5 in the upper tower.

A second overflow port 16 is provided above the lower tower liquid storage tank 17 .

Claims (10)

1. a device that realizes deep recovery of boiler flue gas waste heat and air humidification, is characterized in that, comprises boiler (1) and waste heat recovery tower (3), wherein, boiler (1) is provided with natural gas inlet, and described boiler (1) 1) The upper flue gas outlet is respectively connected with the upper tower and the lower tower of the waste heat recovery tower (3); The upper tower of the waste heat recovery tower (3) is provided with a smoke exhaust port; A high temperature humidification flue gas outlet is provided on the lower tower of the waste heat recovery tower (3), and the high temperature humidification flue gas outlet is connected to the inlet of the boiler (1). 2. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 1, wherein a device is provided between the outlet of the boiler (1) and the upper tower of the waste heat recovery tower (3). The first induced draft fan (19). 3. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 1, wherein a device is provided between the outlet of the boiler (1) and the lower tower of the waste heat recovery tower (3). The second induced draft fan (20). 4. A device for realizing deep recovery of waste heat from boiler flue gas and air humidification according to claim 1, characterized in that, in the inner cavity of the upper tower of the waste heat recovery tower (3), the upper towers are sequentially arranged from top to bottom. The tower mist eliminator (6), the upper tower cloth liquid layer (5), the upper tower packing layer (4) and the upper tower liquid storage layer (11), wherein, the exhaust heat recovery tower (3) on the upper tower The smoke port is arranged above the upper tower mist eliminator (6); the upper tower cloth liquid layer (5) is provided with an intermediate water inlet; the upper tower liquid storage layer (11) is provided with an intermediate water outlet, so The intermediate water outlet is connected to the intermediate water inlet through the heat pump (2). 5. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 4, characterized in that, the flue gas inlet on the upper tower of the waste heat recovery tower (3) is arranged in the upper tower to store liquid between layer (11) and upper tower packing layer (4). 6. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 4, wherein the upper tower of the waste heat recovery tower (3) is also provided with a first overflow port (10). ), the first overflow port (10) is arranged above the upper tower liquid storage layer (11); the bottom of the upper tower liquid storage layer (11) is provided with an intermediate water outlet, and the intermediate water outlet and waste heat The lower tower of the recovery tower (3) is communicated. 7. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 4, characterized in that, between the intermediate water outlet on the upper tower liquid storage layer (11) and the heat pump (2) A first valve (8) and a first water pump (9) are arranged in sequence. 8. A device for realizing deep recovery and air humidification of boiler flue gas waste heat according to claim 1, characterized in that, the inner cavity of the lower tower of the waste heat recovery tower (3) is sequentially arranged from top to bottom with The lower tower cloth liquid layer (13), the lower tower packing layer (12) and the lower tower liquid storage layer (17); wherein, the high temperature humidification flue gas outlet on the lower tower of the waste heat recovery tower (3) is arranged in the lower tower cloth Above the liquid layer (13); the lower tower cloth liquid layer (13) is provided with an intermediate water inlet, and the intermediate water inlet is communicated with the upper tower of the waste heat recovery tower (3); the lower tower liquid storage layer (17) ) is provided with an intermediate water outlet, which is communicated with the upper tower of the waste heat recovery tower (3); the flue gas inlet and the air inlet on the lower tower of the waste heat recovery tower (3) are all arranged in the lower tower liquid storage layer (17) and the lower tower packing layer (12). 9. A device for realizing deep recovery and air humidification of boiler flue gas waste heat according to claim 8, wherein the lower tower of the waste heat recovery tower (3) is also provided with a second overflow port (16). ), the second overflow port (16) is arranged above the liquid storage layer (17) of the lower tower. 10. A device for realizing deep recovery of boiler flue gas waste heat and air humidification according to claim 8, characterized in that the intermediate water outlet and the waste heat recovery tower (3) provided on the lower tower liquid storage layer (17) A second valve (14) and a second water pump (15) are arranged between the upper towers of the ) in sequence.

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