CN218544490U - Flue gas waste heat recovery device of coupling carbon entrapment - Google Patents

Abstract

The utility model provides a flue gas waste heat recovery device of coupling carbon entrapment, including desulfurizing tower, flash tank, absorption tower and desorption tower, wherein, the flue gas outlet that sets up on the desulfurizing tower is connected the flue gas entry that sets up on the absorption tower; a slurry outlet arranged on the desulfurizing tower is connected with a slurry inlet arranged on the flash tank; a rich liquid outlet arranged on the absorption tower is connected with a rich liquid inlet arranged on the desorption tower; a barren liquor outlet arranged on the desorption tower is connected with a barren liquor inlet arranged on the absorption tower; a slurry outlet arranged on the flash tank is connected with a slurry inlet arranged on the desulfurizing tower; a flue gas outlet is formed in the absorption tower; the utility model discloses can effectively reduce the consumption to the steam of power plant among the MEA regeneration process to reduce regeneration energy consumption, and can effectively reduce desulfurizing tower exhaust flue gas temperature.

Description

A flue gas waste heat recovery device coupled with carbon capture

technical field

The utility model belongs to the field of environment, in particular to a flue gas waste heat recovery device coupled with carbon capture.

Background technique

The MEA monoethanolamine method is a common method for capturing CO2. The regeneration cycle is realized through the absorption and desorption of MEA. However, the regeneration process requires the use of high-temperature heat sources. Generally, steam turbines in power plants are used to extract steam, resulting in high overall energy consumption of the technology. At the same time, the flue gas temperature at the outlet of the wet desulfurization tower of a coal-fired power plant is relatively high, which is higher than the requirements of the MEA process for flue gas temperature, and the _CO2 absorption rate is low.

For combined heat and power units, recovering waste heat from the system is one of the best ways to increase heating capacity without increasing the size of the unit. At present, power plants usually use water spraying method to reduce the flue gas to 50~60°C before discharging, and the heat in it is not recovered, resulting in a waste of energy.

CN 109454620 A discloses a coupling device for carbon capture and waste heat recovery, which utilizes an absorption tower and a desorption tower to capture and store CO ₂ in high-temperature flue gas discharged from industry, and perform certain waste heat recovery. However, in this scheme, the utilization of waste heat of flue gas is relatively rough, and the temperature of flue gas in the absorption tower is high, and the _CO2 absorption rate is low.

Contents of the invention

The purpose of this utility model is to provide a flue gas waste heat recovery device coupled with carbon capture, which solves the problem that although the existing technology can achieve a certain purpose of recovering waste heat, the heat recovery rate is low. At the same time, the absorption tower in the prior art The problem of high inlet flue gas temperature and low _CO2 absorption rate.

In order to achieve the above object, the technical scheme that the utility model adopts is:

The utility model provides a flue gas waste heat recovery device coupled with carbon capture, which includes a desulfurization tower, a flash tank, an absorption tower and a desorption tower, wherein the flue gas outlet set on the desulfurization tower is connected to the flue gas outlet set on the absorption tower flue gas inlet; the slurry outlet provided on the desulfurization tower is connected to the slurry inlet provided on the flash tank;

The rich liquid outlet provided on the absorption tower is connected to the rich liquid inlet provided on the desorption tower;

The lean liquid outlet provided on the desorption tower is connected to the lean liquid inlet provided on the absorption tower;

The slurry outlet provided on the flash tank is connected to the slurry inlet provided on the desulfurization tower;

A flue gas outlet is arranged on the absorption tower.

Preferably, a heat exchange unit is arranged between the absorption tower and the desorption tower.

Preferably, the steam outlet provided on the flash tank is connected to the steam inlet provided on the heat exchange unit.

Preferably, the connection unit includes a lean-rich liquid heat exchanger and an absorption heat pump, wherein the rich liquid outlet on the absorption tower is connected to the rich liquid outlet on the desorption tower through the lean-rich liquid heat exchanger and the absorption heat pump in sequence. liquid inlet.

Preferably, the connecting unit further includes a lean liquid cooler, wherein the lean liquid outlet on the desorption tower is connected to the lean liquid inlet on the absorption tower through a lean-rich liquid heat exchanger and a lean liquid cooler in sequence.

Preferably, the absorption heat pump is provided with a driving steam inlet and a first condensed water outlet, and the first condensed water outlet is connected to a clean water tank.

Preferably, the absorption heat pump is provided with a second condensed water outlet.

Preferably, the carbon dioxide outlet provided on the desorption tower is connected to the gas inlet on the condenser; the condenser is provided with a gas outlet and a liquid outlet, and the liquid outlet is connected to the liquid inlet provided on the desorption tower.

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

The utility model provides a flue gas waste heat recovery device coupled with carbon capture, which reduces the temperature of the desulfurization slurry by flashing the desulfurization slurry, thereby reducing the temperature of the flue gas discharged from the desulfurization tower to about 40°C, which is the best for MEA to absorb CO ₂ temperature to increase the absorption rate; through the desulfurization slurry flash evaporation, the heat of the flue gas is actually recovered, and this part of the heat is used to heat the MEA rich liquid after being upgraded by the absorption heat pump, which can effectively reduce the impact on the power plant steam during the MEA regeneration process. Consumption, thereby reducing regeneration energy consumption.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

The utility model provides a flue gas waste heat recovery device coupled with carbon capture, including a desulfurization tower 1, a flash tank 4, an absorption tower 2 and a desorption tower 3, wherein the flue gas outlet provided on the desulfurization tower 1 is connected to The flue gas inlet provided on the absorption tower 2; the slurry outlet provided on the desulfurization tower 1 is connected to the slurry inlet provided on the flash tank 4;

The rich liquid outlet provided on the absorption tower 2 is connected to the rich liquid inlet provided on the desorption tower 3;

The lean liquid outlet provided on the desorption tower 3 is connected to the lean liquid inlet provided on the absorption tower 2;

The slurry outlet provided on the flash tank 4 is connected to the slurry inlet provided on the desulfurization tower 1;

The absorption tower 2 is provided with a flue gas outlet.

The utility model provides a flue gas waste heat recovery method coupled with carbon capture, comprising the following steps:

The flue gas 9 enters the desulfurization tower 1 to exchange heat with the low-temperature desulfurization slurry 12 sprayed from the top of the tower and is purified, and the flue gas is cooled and humidified;

The high-temperature desulfurization slurry 10 at the bottom of the desulfurization tower 1 enters the flash tank 4 to generate flash steam 13 and low-temperature desulfurization slurry 12, and heat is transferred from the desulfurization slurry to the flash steam;

The saturated wet flue gas 11 purified from the desulfurization tower 1 enters the absorption tower 2 and contacts the MEA poor liquid sprayed from the top of the tower in countercurrent, the CO ₂ in the flue gas is absorbed, and the flue gas 18 after the CO ₂ is absorbed is absorbed Discharge from the top of the tower;

The rich MEA liquid 17 is discharged from the bottom of the absorption tower 2 and enters the desorption tower 3 for desorption; the desorbed MEA poor liquid 20 enters the absorption tower 2 for circulation.

As shown in Figure 1, a flue gas waste heat recovery device coupled with carbon capture provided by the utility model includes a desulfurization tower 1, an absorption tower 2, a desorption tower 3, a flash tank 4, an absorption heat pump 5, a lean-rich Liquid heat exchanger 6, lean liquid cooler 7, condenser 8, flue gas 9, high temperature desulfurization slurry 10, saturated wet flue gas 11, low temperature desulfurization slurry 12, flash steam 13, condensed water 14, driving steam 15, condensation Water 16, MEA rich liquid 17, flue gas 18, high temperature rich liquid 19, MEA lean liquid 20, CO ₂ rich gas 21 and high-purity CO ₂ 22, wherein, the desulfurization tower 1 is provided with flue gas inlet and flue gas outlet, the flue gas inlet provided on the flue gas outlet absorption tower 2; the slurry outlet provided on the desulfurization tower 1 is connected to the slurry inlet provided on the flash tank 4; the slurry outlet provided on the flash tank 4 is connected to The slurry inlet opened on the desulfurization tower 1.

The steam outlet opened on the flash tank 4 is connected to the steam inlet on the absorption heat pump 5 .

The absorption heat pump 5 is provided with a driving steam inlet and a first condensed water outlet, and the first condensed water outlet is connected to a clean water tank.

The absorption heat pump 5 is provided with a second condensed water outlet.

The MEA rich liquid outlet on the absorption tower 2 is connected to the MEA rich liquid inlet on the desorption tower 3 through the lean-rich liquid heat exchanger 6 and the absorption heat pump 5 in sequence.

The MEA lean liquid outlet on the desorption tower 3 passes through the lean-rich liquid heat exchanger 6 and the lean liquid cooler 7 sequentially to connect to the MEA lean liquid inlet provided on the absorption tower 2 .

The absorption tower 2 is provided with a flue gas outlet.

The carbon dioxide outlet provided on the desorption tower 3 is connected to the gas inlet provided on the condenser 8 .

The liquid outlet provided on the condenser 8 is connected to the liquid inlet provided on the desorption column 3 .

The condenser 8 is provided with a gas outlet.

Working principle of the utility model:

The flue gas 9 enters the desulfurization tower 1 to exchange heat with the low-temperature desulfurization slurry 12 sprayed from the top of the tower and is purified, and the flue gas is cooled and humidified. The high-temperature desulfurization slurry 10 at the bottom of the desulfurization tower enters the flash tank 4, and flashes in a vacuum environment to generate flash steam 13 and low-temperature desulfurization slurry 12, and heat is transferred from the desulfurization slurry to the flash steam.

The flash steam 13 enters the absorption heat pump 5, and the driving steam 15 is used to upgrade the quality and heat the MEA rich liquid.

The driving steam is condensed in the heat pump to form condensed water 16 and returned to the clean water tank, and the flash steam 13 is condensed to be condensed water 14 for desulfurization replenishment.

The purified saturated wet flue gas 11 enters the absorption tower 2 and contacts the MEA lean liquid sprayed from the top of the tower in countercurrent, the CO ₂ in the flue gas is absorbed, and the flue gas 18 after the CO ₂ is absorbed is discharged from the top of the absorption tower.

The MEA rich liquid 17 is discharged from the bottom of the absorption tower, and after being heated by the lean-rich liquid heat exchanger 6, it enters the heat pump 5 to further heat up into a high-temperature rich liquid 19, and then enters the desorption tower 3 for desorption.

The desorbed MEA lean liquid 20 is cooled by the lean-rich liquid heat exchanger and the lean liquid cooler 7, and then enters the absorption tower for circulation. The desorbed CO ₂ rich gas 21 is discharged from the top of the tower into a condenser for gas-liquid separation, and further compressed to obtain high-purity CO ₂ 22.

The utility model reduces the temperature of the desulfurization slurry by flashing the desulfurization slurry, thereby reducing the temperature of the flue gas discharged from the desulfurization tower to about 40°C, reaching the optimum temperature for the MEA to absorb CO2, and improving the absorption rate. Flash evaporation of desulfurization slurry actually recovers the heat of the flue gas. This part of the heat is upgraded by the absorption heat pump and used to heat the MEA rich liquid, which can effectively reduce the consumption of power plant steam during the MEA regeneration process, thereby reducing the regeneration energy. consumption.

Claims (8)

1. A flue gas waste heat recovery device coupled with carbon capture, characterized in that it comprises a desulfurization tower (1), a flash tank (4), an absorption tower (2) and a desorption tower (3), wherein the desulfurization The flue gas outlet provided on the tower (1) is connected to the flue gas inlet provided on the absorption tower (2); the slurry outlet provided on the desulfurization tower (1) is connected to the slurry inlet provided on the flash tank (4); The rich liquid outlet provided on the absorption tower (2) is connected to the rich liquid inlet provided on the desorption tower (3); The lean liquid outlet provided on the desorption tower (3) connects the lean liquid inlet provided on the absorption tower (2); The slurry outlet provided on the flash tank (4) is connected to the slurry inlet provided on the desulfurization tower (1); The absorption tower (2) is provided with a flue gas outlet. 2. A flue gas waste heat recovery device coupled with carbon capture according to claim 1, characterized in that a heat exchange unit is arranged between the absorption tower (2) and the desorption tower (3). 3. A flue gas waste heat recovery device coupled with carbon capture according to claim 2, characterized in that the steam outlet provided on the flash tank (4) is connected to the steam inlet provided on the heat exchange unit. 4. A flue gas waste heat recovery device coupled with carbon capture according to claim 2, characterized in that the heat exchange unit comprises a lean-rich liquid heat exchanger (6) and an absorption heat pump (5), Wherein, the rich liquid outlet on the absorption tower (2) is sequentially connected to the rich liquid inlet on the desorption tower (3) through a lean-rich liquid heat exchanger (6) and an absorption heat pump (5). 5. A flue gas waste heat recovery device coupled with carbon capture according to claim 4, characterized in that the heat exchange unit further comprises a lean liquid cooler (7), wherein the desorption tower (3) The lean liquid outlet on the upper part is connected to the lean liquid inlet on the absorption tower (2) through the lean-rich liquid heat exchanger (6) and the lean liquid cooler (7) in sequence. 6. A flue gas waste heat recovery device coupled with carbon capture according to claim 4, characterized in that the absorption heat pump (5) is provided with a drive steam inlet and a first condensed water outlet, and the second A condensed water outlet is connected to the clean water tank. 7. The flue gas waste heat recovery device coupled with carbon capture according to claim 4, characterized in that, the absorption heat pump (5) is provided with a second condensed water outlet. 8. A flue gas waste heat recovery device coupled with carbon capture according to claim 4, characterized in that the carbon dioxide outlet provided on the desorption tower (3) is connected to the gas inlet on the condenser (8); The condenser (8) is provided with a gas outlet and a liquid outlet, and the liquid outlet is connected to the liquid inlet provided on the desorption column (3).

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