阅读说明：本技术 分离回收高炉煤气中二氧化碳的吸收剂及方法 (Absorbent and method for separating and recovering carbon dioxide in blast furnace gas ) 是由 黄显著 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种高炉煤气分离回收二氧化碳的吸收剂及方法,包括：煤气洗涤降温,煤气增压,将增压后的煤气自吸收塔的下部通入吸收塔至塔内的压力达到0.3MPa～10MPa,再继续通入煤气,同时将吸收剂经吸收塔上部的喷嘴喷洒于塔中,使煤气与吸收剂充分接触以除去煤气中的二氧化碳。本发明能够有效地脱除煤气中的二氧化碳气体,煤气中二氧化碳浓度降至0.75%以下。吸收剂能够再生,再生效率达到97%以上。(The invention discloses an absorbent and a method for separating and recovering carbon dioxide from blast furnace gas, comprising the following steps: and (2) washing and cooling the coal gas, pressurizing the coal gas, introducing the pressurized coal gas into the absorption tower from the lower part of the absorption tower until the pressure in the tower reaches 0.3-10 MPa, continuously introducing the coal gas, and spraying an absorbent into the tower through a nozzle at the upper part of the absorption tower to fully contact the coal gas with the absorbent so as to remove carbon dioxide in the coal gas. The invention can effectively remove the carbon dioxide gas in the coal gas, and the concentration of the carbon dioxide in the coal gas is reduced to be below 0.75 percent. The absorbent can be regenerated, and the regeneration efficiency reaches more than 97%.)

1. The absorbent for separating and recovering the carbon dioxide in the blast furnace gas is characterized by comprising 5-90% by mass of at least one of choline eutectic solvents or imidazole ionic liquids, 0.01-0.1% by mass of graphene oxide and the balance of water.

2. The absorbent for separating and recovering carbon dioxide from blast furnace gas according to claim 1, wherein the specific surface area of graphene oxide in the absorbent is not less than 500m²/g。

3. The absorbent for separating and recovering carbon dioxide from blast furnace gas according to claim 1, wherein the mass concentration of graphene oxide in the absorbent is 0.01% to 0.05%.

4. The absorbent for separating and recovering carbon dioxide from blast furnace gas according to claim 1, wherein the absorbent comprises 20 to 50 mass percent of choline eutectic solvent or imidazole ionic liquid, 0.01 to 0.1 mass percent of graphene oxide, and the balance of water.

5. The absorbent for separating and recovering carbon dioxide from blast furnace gas according to claim 1 or 4, characterized in that the imidazole-based ionic liquid is in the form of [ C ]_nmim][X]Cn represents straight chain alkane, n is 1, 2 and 3, X is fluorine, chlorine, bromine, iodine, tetrafluoroborate and hexafluorophosphateOne of a root and a bistrifluoromethylsuccinimide root; the choline eutectic solvent is one of choline chloride, choline proline, choline glycine, choline alanine and choline lysine.

6. A method for separating and recovering carbon dioxide from blast furnace gas by using the absorbent according to any one of claims 1 to 5, characterized by comprising the steps of:

(1) the blast furnace gas is dedusted and cooled by a washing cooling tower to be cooled to below 60 ℃;

(2) pressurizing the coal gas to 0.3-10 MPa;

(3) and introducing the pressurized coal gas into the absorption tower from the lower part of the absorption tower until the pressure in the absorption tower reaches 0.3-10 MPa, continuously introducing the coal gas, and spraying an absorbent into the tower through a nozzle at the upper part of the absorption tower to fully contact the coal gas with the absorbent so as to remove carbon dioxide in the coal gas.

7. The method according to claim 6, wherein the pressure in the absorption tower is 0.3MPa to 10MPa, and the ratio of the mass flow of the absorbent to the volume flow of the gas is 5 to 200: 1, the mass flow unit of the absorbent is as follows: kg/h, the volume flow of coal gas is as follows: nm³/h。

8. The method according to claim 6, wherein the absorbent absorbing carbon dioxide in the step (3) enters a flash tank for regeneration treatment, wherein the pressure in the flash tank is 0.1-0.6 MPa, and the temperature is 15-30 ℃; and conveying the flash evaporated absorbent to an absorption tower through an absorption liquid conveying pump for heat treatment, wherein the heat treatment is carried out at normal pressure and at the temperature of 60-80 ℃ so as to further analyze carbon dioxide in the absorbent, the analyzed liquid enters an absorption liquid storage tank for cooling, and the cooled absorption liquid is conveyed to the absorption tower through a booster pump for recycling.

9. The method according to claim 6, wherein in the step (3), the temperature in the absorption column is 30 ℃-40 ℃ of temperature; the pressure in the absorption tower is 0.8MPa to 3 MPa; the ratio of the mass flow of the absorbent to the volume flow of the coal gas is 10-50: 1, the mass flow unit of the absorbent is as follows: kg/h, the volume flow of coal gas is as follows: nm³/h。

10. The method for separating and recovering carbon dioxide from blast furnace gas according to claim 6, wherein the absorption device comprises: the device comprises a washing cooling tower, a pressurization system, an absorption tower, a gas-liquid separation tank, a flash tank, an absorption liquid booster pump, a desorption tower, an absorbent circulating pump and an absorption liquid storage tank; the blast furnace gas is connected with an inlet of a washing and cooling tower, a wire mesh defoaming device and a filler for drying are arranged at the upper part of the washing and cooling tower, an outlet at the upper part of the washing and cooling tower is connected with an inlet of an absorption tower through a pressurization system, at least one layer of nozzles is arranged at the upper part of the absorption tower, and an air outlet at the top of the absorption tower is connected with a gas-liquid separation tank; the liquid outlet at the bottom of the absorption tower is connected with the absorbent inlet of the flash tank, the liquid outlet at the bottom of the flash tank is connected with the inlet of an absorption liquid booster pump, the outlet of the booster pump is connected with the inlet at the upper part of the desorption tower, the top of the desorption tower is provided with an exhaust port, and the liquid outlet at the bottom of the desorption tower is connected with an absorption liquid storage tank; the absorbent storage tank is connected with a nozzle of the absorption tower through an absorbent circulating pump.

Technical Field

The invention relates to an absorbent and a method for separating and recovering carbon dioxide from blast furnace gas in the utilization process of the blast furnace gas, belonging to the technical fields of gas purification, environmental protection, energy conservation and consumption reduction.

Background

With the increasing prominence of global warming problem, CO is reduced₂Emissions become a challenge for all mankind. The iron and steel industry is based on carbon metallurgy, and CO is generated in the production process₂Emission of CO in the world₂5 to 6 percent of total emission, blast furnace ironmaking CO₂The emission amount of CO accounts for the whole steel production₂70% of the emission, thereby reducing CO in the ironmaking process₂The discharge is trueThe key way of carbon reduction in the steel industry is available.

Currently, the technologies for capturing carbon dioxide industrially mainly include: absorption, adsorption, condensation, membrane separation, and the like. The absorption method has the advantages of low energy consumption, strong operability, large handling capacity and the like, and is widely concerned and industrially applied.

Chinese patent CN 102341509B discloses a method for separating and recovering carbon dioxide from blast furnace gas in the process of blast furnace gas utilization, which mainly comprises the following steps: the device comprises a dust collector, a first Venturi scrubber, a second Venturi scrubber, a dry dust collector, an absorption tower, an auxiliary absorption tower, a regeneration tower, a blast furnace gas compressor and the like. The method adopts a chemical absorption method to capture carbon dioxide, and utilizes the heat of gas combustion to heat the absorbent to realize the recycling of the absorption liquid. The method does not select proper absorbent, has long operation flow and large equipment investment after industrial amplification.

Chinese patent CN 106540660B discloses a method for absorbing CO₂An ionic liquid adsorbing material for gas and a preparation method thereof. The method comprises the steps of mixing mesitylene, ammonium fluoride and a silicon source compound, and calcining to obtain a carrier; and then putting the carrier into an ethanol solution of the ionic liquid, and then mixing and drying the carrier and the ethanol solution to obtain the ionic liquid adsorbing material. The method is suitable for the operation working condition with low treatment capacity, is difficult to realize industrial amplification and has low repeatability.

Disclosure of Invention

The invention aims to provide a solvent and a method for separating carbon dioxide from blast furnace gas, aiming at the defects of long flow, high cost, difficult repetition of an absorbent and low absorption amount of a blast furnace gas carbon dioxide removing device in the prior art. The method can improve the absorption effect, reduce the process flow and reduce the regeneration energy consumption of the absorbent, thereby reducing the preparation cost of separating the carbon dioxide from the blast furnace gas.

The purpose of the invention is realized by the following technical scheme: the absorbent for separating and recovering the carbon dioxide in the blast furnace gas comprises at least one of choline eutectic solvents or imidazole ionic liquids with the mass fraction of 5-90%, graphene oxide with the mass fraction of 0.01-0.1% and the balance of water.

Generally, in the absorbent, the specific surface area of the graphene oxide is not less than 500m²/g。

In the absorbent, the mass concentration of the graphene oxide is 0.01-0.05%.

The absorbent comprises 20-50% of choline eutectic solvent or imidazole ionic liquid, 0.01-0.1% of graphene oxide and the balance of water.

The imidazole ionic liquid is in the form of [ C_nmim][X]Cn represents straight-chain alkane, n is 1, 2 and 3, and X is one of fluorine, chlorine, bromine, iodine, tetrafluoroborate, hexafluorophosphate and bistrifluoromethylsuccinimide; the choline eutectic solvent is one of choline chloride, choline proline, choline glycine, choline alanine and choline lysine.

The invention also provides a method for separating and recovering carbon dioxide in blast furnace gas by using the absorbent, which mainly comprises the following steps:

(1) the blast furnace gas is dedusted and cooled by a washing cooling tower to be cooled to below 60 ℃;

(2) pressurizing the coal gas to 0.3-10 MPa;

(3) and introducing the pressurized coal gas into the absorption tower from the lower part of the absorption tower until the pressure in the absorption tower reaches 0.3-10 MPa, continuously introducing the coal gas, and spraying an absorbent into the tower through a nozzle at the upper part of the absorption tower to fully contact the coal gas with the absorbent so as to remove carbon dioxide in the coal gas.

Preferably, the pressure in the absorption tower is 0.3-10 MPa, and the ratio of the mass flow of the absorbent to the volume flow of the coal gas is 5-200: 1, the mass flow unit of the absorbent is as follows: kg/h, the volume flow of coal gas is as follows: nm³/h。

The absorbent absorbing the carbon dioxide in the step (3) enters a flash tank for regeneration treatment, wherein the pressure in the flash tank is 0.1-0.6 MPa, and the temperature is 15-30 ℃; and conveying the flash evaporated absorbent to an absorption tower through an absorption liquid conveying pump for heat treatment, wherein the heat treatment is carried out at normal pressure and at the temperature of 60-80 ℃ so as to further analyze carbon dioxide in the absorbent, the analyzed liquid enters an absorption liquid storage tank for cooling, and the cooled absorption liquid is conveyed to the absorption tower through a booster pump for recycling.

In the step (3), the temperature in the absorption tower is 30-40 ℃; the pressure in the absorption tower is 0.8MPa to 3 MPa; the ratio of the mass flow of the absorbent to the volume flow of the coal gas is 10-50: 1, the mass flow unit of the absorbent is as follows: kg/h, the volume flow of coal gas is as follows: nm³/h。

The absorption device in the method for separating and recovering the carbon dioxide in the blast furnace gas mainly comprises: the device comprises a washing cooling tower, a pressurization system, an absorption tower, a gas-liquid separation tank, a flash tank, an absorption liquid booster pump, a desorption tower, an absorbent circulating pump and an absorption liquid storage tank; the blast furnace gas is connected with an inlet of a washing and cooling tower, a wire mesh defoaming device and a filler for drying are arranged at the upper part of the washing and cooling tower, an outlet at the upper part of the washing and cooling tower is connected with an inlet of an absorption tower through a pressurization system, at least one layer of nozzles is arranged at the upper part of the absorption tower, and an air outlet at the top of the absorption tower is connected with a gas-liquid separation tank; the liquid outlet at the bottom of the absorption tower is connected with the absorbent inlet of the flash tank, the liquid outlet at the bottom of the flash tank is connected with the inlet of an absorption liquid booster pump, the outlet of the booster pump is connected with the inlet at the upper part of the desorption tower, the top of the desorption tower is provided with an exhaust port, and the liquid outlet at the bottom of the desorption tower is connected with an absorption liquid storage tank; the absorbent storage tank is connected with a nozzle of the absorption tower through an absorbent circulating pump.

In the invention, blast furnace gas (more than 0.2 MPa) enters a washing cooling tower to be cooled to 60 ℃, and dust in the gas is removed to prevent polluting absorption liquid. Washing wastewater is sent to a plant area sedimentation tank, and upper layer clear water can be recycled; pressurizing the washed and cooled coal gas to 0.3-10 MPa by a compressor, introducing the pressurized coal gas into an absorption tower from the lower part of the absorption tower until the pressure in the absorption tower reaches 0.3-10 MPa, continuously introducing the coal gas, spraying an absorbent into the tower through a nozzle at the upper part of the absorption tower, fully contacting the coal gas with the absorbent to remove carbon dioxide in the coal gas, and separating the gas from which the carbon dioxide is removed by a gas-liquid separator to obtain the purified coal gas.

In the invention, the absorbent rich in carbon dioxide enters a flash tank for regeneration treatment, the pressure in the flash tank is 0.1-0.6 MPa, and the temperature is normal temperature (15-30 ℃); and conveying the flash evaporated absorbent to a desorption tower through an absorption liquid conveying pump for heat treatment (at the temperature of 60-80 ℃) so as to further desorb the carbon dioxide in the absorbent. And the desorbed liquid enters an absorption liquid storage tank for cooling, and the cooled absorption liquid is conveyed to the absorption tower through a booster pump for cyclic utilization.

In the implementation process of the invention, the operation pressure of the separation process, the content of ionic liquid in the absorbent, the content of graphene oxide and the requirement of separation indexes all influence the implementation effect of the invention.

The invention has the technical effects that: according to the invention, by constructing a method for separating and recovering carbon dioxide from blast furnace gas, the ionic liquid (choline eutectic solvent and imidazole ionic liquid) and the graphene oxide aqueous solution are used as absorbents, the ionic liquid has good stability, the graphene oxide mixed with the ionic liquid has great solubility to gas, carbon dioxide in the blast furnace gas can be effectively removed, and the concentration of carbon dioxide in the obtained purified gas is reduced to below 0.75%. The absorbent can be regenerated, and the regeneration efficiency reaches more than 97%. The absorbent has low regeneration energy consumption, convenient equipment operation and lower investment.

Drawings

FIG. 1 is a schematic view of a process flow for separating absorbed carbon dioxide from blast furnace gas according to an embodiment of the present invention.

FIG. 1: 1-a washing cooling tower, 2-a gas compressor, 3-an absorption tower, 4-a gas-liquid separator, 5-a flash tank, 6-an absorption liquid delivery pump, 7-a desorption tower, 8-an absorption liquid storage tank and 9-a booster pump.

Detailed Description

The present invention will be described in detail below with reference to examples and the accompanying drawings.

The invention can be changed according to the actual working condition and the field requirement in the implementation process. The examples given in this invention are only used as references to provide the selection of the concentration of each component of the absorbent under different conditions, but the application of the invention is not limited to the operation conditions given in the examples.

The absorption scheme in the following examples refers to FIG. 1.

Example 1

Blast furnace gas (33% by volume, the same below) (carbon dioxide, 41% carbon monoxide, 9.5% hydrogen, 0.3% methane, 10% nitrogen and 6% water) is dedusted and cooled in a washing cooling tower 01, the cooled gas (50 ℃) is pressurized to 1.2MPa by a compressor 02 (33.8% carbon dioxide, 41.99% carbon monoxide, 9.73% hydrogen, 0.31% methane, 10.24% nitrogen and 3.88% water), and the pressurized gas is pressurized to 8000Nm³The flow velocity of/h is introduced into the absorption tower 03 from the lower part of the absorption tower 03 until the pressure in the tower reaches 1.2MPa, then the gas is continuously introduced at the same flow velocity, and simultaneously the absorbent (the mass fraction of the [ Cnim ] is 10 percent)][PF₆]Specific surface area of 600m²0.01 percent of graphene oxide in terms of mass concentration/g and 89.99 percent of water in terms of mass fraction) is conveyed to an absorption tower 03 at a flow rate of 16000kg/h, and is sprayed into the tower from a nozzle at the upper part in the tower. In the process, the pressure in the tower is maintained at 1.2MPa and the temperature is 35 ℃, so that the coal gas is fully contacted with the absorbent to remove carbon dioxide in the coal gas, and the content of the carbon dioxide in the coal gas is detected and analyzed to be 0.86 percent (volume fraction) after the coal gas is separated by the gas-liquid separation tank 04.

The absorbent coming out from the bottom of the absorption tower 03 is flashed by a flash tank 05 (with the pressure of 0.2MPa and the temperature of 30 ℃), and the separated carbon dioxide is sent to the next working procedure for later use. The liquid at the bottom of the tank is pressurized by a booster pump 06 and then is conveyed to a desorption tower 07 (at the temperature of 70 ℃, under normal pressure) for heat treatment and regeneration, and carbon dioxide in the liquid is further desorbed. The tower bottom liquid is sent to an absorption liquid storage tank 08 for cooling and recycling. The regeneration efficiency of the absorbent is more than 97 percent.

Example 2

Blast furnace gas (volume fraction, the same below) (33% carbon dioxide, 41% carbon monoxide, 9.5% hydrogen, 0.3% methane, 10% nitrogen and 6% water) is dedusted and cooled in a washing cooling tower 01, and the cooled gas (temperature 50 deg.C) (33.8% carbon dioxide)41.99 percent of carbon monoxide, 9.73 percent of hydrogen, 0.31 percent of methane, 10.24 percent of nitrogen and 3.88 percent of water) are pressurized to 1.2MPa by a compressor 02, and the pressurized coal gas is 8000Nm³The flow velocity is introduced into the absorption tower 03 from the lower part of the absorption tower 03 until the pressure in the tower reaches 1.2MPa, then the gas is continuously introduced at the same flow velocity, and meanwhile, the absorbent regenerated in the example 1 is conveyed to the absorption tower 03 at the flow velocity of 16000kg/h, and is sprayed into the tower from a nozzle at the upper part in the tower. In the process, the pressure in the tower is maintained at 1.2MPa and the temperature is 35 ℃, so that the coal gas is fully contacted with the absorbent to remove carbon dioxide in the coal gas, and the content of the carbon dioxide in the coal gas is detected and analyzed to be 0.87 percent (volume fraction) after the coal gas is separated by the gas-liquid separation tank 04.

Examples 3 to 7

Blast furnace gas (volume fraction, the same below) (carbon dioxide 33%, carbon monoxide 41%, hydrogen 9.5%, methane 0.3%, nitrogen 10%, water 6%) is dedusted and cooled in a washing cooling tower 01, the cooled gas (temperature 50 ℃) (carbon dioxide 33.8%, carbon monoxide 41.99%, hydrogen 9.73%, methane 0.31%, nitrogen 10.24%, water 3.88%) is pressurized to (0.8 MPa, 1.0MPa, 1.2MPa, 1.4MPa, 1.6 MPa) by a compressor 02, and the pressurized gas is 8000Nm³The flow velocity is introduced into the absorption tower 03 from the lower part of the absorption tower 03 until the pressure in the tower reaches (0.8 MPa, 1.0MPa, 1.2MPa, 1.4MPa and 1.6 MPa), then the coal gas is continuously introduced at the same flow velocity, and simultaneously the absorbent (choline chloride with the mass fraction of 15 percent and the specific surface area of 600 m) is introduced²0.01 percent of graphene oxide in terms of mass concentration/g and 84.99 percent of water in terms of mass fraction) is conveyed to an absorption tower 03 at a flow rate of 16000kg/h, and is sprayed into the tower from a nozzle at the upper part in the tower. In the process, the pressure in the tower is maintained at (0.8 MPa, 1.0MPa, 1.2MPa, 1.4MPa, 1.6 MPa) and the temperature is kept at 35 ℃, so that the coal gas is fully contacted with the absorbent to remove the carbon dioxide in the coal gas.

The absorbent coming out from the bottom of the absorption tower 03 is flashed by a flash tank 05 (with the pressure of 0.2MPa and the temperature of 30 ℃), and the separated carbon dioxide is sent to the next working procedure for later use. The liquid at the bottom of the tank is pressurized by a booster pump 06 and then is conveyed to a desorption tower 07 (at the temperature of 70 ℃, under normal pressure) for heat treatment and regeneration, and carbon dioxide in the liquid is further desorbed. The tower bottom liquid is sent to an absorption liquid storage tank 08 for cooling and recycling.

The content of each main component in the gas at the outlet of the absorption tower is detected and analyzed under different absorption pressure conditions as shown in the following table (volume fraction).

As can be seen from the table, the absorption effect is promoted by the pressure in the absorption column, and the higher the pressure is, the better the absorption effect is.

Examples 8 to 13

Blast furnace gas (33% by volume, the same below) (carbon dioxide, 41% carbon monoxide, 9.5% hydrogen, 0.3% methane, 10% nitrogen and 6% water) is dedusted and cooled in a washing cooling tower 01, the cooled gas (50 ℃) is pressurized to 1.2MPa by a compressor 02 (33.8% carbon dioxide, 41.99% carbon monoxide, 9.73% hydrogen, 0.31% methane, 10.24% nitrogen and 3.88% water), and the pressurized gas is pressurized to 8000Nm³Introducing the gas into the absorption tower 03 from the lower part of the absorption tower 03 at a flow velocity until the pressure in the absorption tower 03 reaches 1.2MPa, continuing introducing the gas at the same flow velocity, and simultaneously introducing the choline chloride of the absorbent (the mass fraction of the choline chloride is 5%, 15%, 25%, 35%, 50%, 90%) with a specific surface area of 600m²0.01% graphene oxide mass concentration/g, water mass fraction (94.99%, 84.99%, 74.99%, 64.99%, 49.99%, 9.99%)) was fed to the absorption column 03 at a flow rate of 16000kg/h, and sprayed into the column from a nozzle at the upper portion of the column. In the process, the pressure in the tower is maintained at 1.2MPa and the temperature is kept at 35 ℃, so that the coal gas is fully contacted with the absorbent to remove carbon dioxide in the coal gas.

The absorbent coming out from the bottom of the absorption tower 03 is flashed by a flash tank 05 (with the pressure of 0.2MPa and the temperature of 30 ℃), and the separated carbon dioxide is sent to the next working procedure for later use. The liquid at the bottom of the tank is pressurized by a booster pump 06 and then is conveyed to a desorption tower 07 (at the temperature of 70 ℃, under normal pressure) for heat treatment and regeneration, and carbon dioxide in the liquid is further desorbed. The tower bottom liquid is sent to an absorption liquid storage tank 08 for cooling and recycling.

The content of each main component in the gas at the outlet of the detection and analysis absorption tower is shown in the following table (volume fraction) under different absorbent compositions.

The mass concentration of ionic liquid in the absorbent has a significant influence on the absorption effect, but the absorption effect tends to increase and then decrease under a certain pressure. The ionic liquid with the concentration of 20-50% is more economical, and the absorption effect is better.

Examples 14 to 18

Blast furnace gas (33% by volume, the same below) (carbon dioxide, 41% carbon monoxide, 9.5% hydrogen, 0.3% methane, 10% nitrogen and 6% water) is dedusted and cooled in a washing cooling tower 01, the cooled gas (50 ℃) is pressurized to 1.2MPa by a compressor 02 (33.8% carbon dioxide, 41.99% carbon monoxide, 9.73% hydrogen, 0.31% methane, 10.24% nitrogen and 3.88% water), and the pressurized gas is pressurized to 8000Nm³The flow velocity is introduced into the absorption tower 03 from the lower part of the absorption tower 03 until the pressure in the tower reaches 1.2MPa, then the coal gas is continuously introduced at the same flow velocity, and simultaneously an absorbent (choline chloride with the mass fraction of 15 percent and the specific surface area of 600 m) is introduced²The graphene oxide mass concentration per g (0.01%, 0.03%, 0.05%, 0.1%), the water mass fraction (84.99%, 84.97%, 84.95%, 84.90%) was fed to the absorption column 03 at a flow rate of 16000kg/h, and sprayed into the column from a nozzle at the upper part inside the column. In the process, the pressure in the tower is maintained at 1.2MPa and the temperature is kept at 35 ℃, so that the coal gas is fully contacted with the absorbent to remove carbon dioxide in the coal gas.

The absorbent coming out from the bottom of the absorption tower 03 is flashed by a flash tank 05 (with the pressure of 0.2MPa and the temperature of 30 ℃), and the separated carbon dioxide is sent to the next working procedure for later use. The liquid at the bottom of the tank is pressurized by a booster pump 06 and then is conveyed to a desorption tower 07 (at the temperature of 70 ℃, under normal pressure) for heat treatment and regeneration, and carbon dioxide in the liquid is further desorbed. The tower bottom liquid is sent to an absorption liquid storage tank 08 for cooling and recycling.

The content of each main component in the gas at the outlet of the detection and analysis absorption tower is shown in the following table (volume fraction) under different absorbent compositions.

The concentration of graphene oxide in the absorbent may also have an effect on the absorption effect. Under the same other conditions, the absorbent with the graphene oxide concentration of 0.01-0.05% can remove carbon dioxide in the coal gas more economically and effectively.

Examples 18 to 22

Blast furnace gas (33% by volume, the same below) (carbon dioxide, 41% carbon monoxide, 9.5% hydrogen, 0.3% methane, 10% nitrogen and 6% water) is dedusted and cooled in a washing cooling tower 01, the cooled gas (50 ℃) is pressurized to 1.2MPa by a compressor 02 (33.8% carbon dioxide, 41.99% carbon monoxide, 9.73% hydrogen, 0.31% methane, 10.24% nitrogen and 3.88% water), and the pressurized gas is pressurized to 8000Nm³The flow velocity is introduced into the absorption tower 03 from the lower part of the absorption tower 03 until the pressure in the tower reaches 1.2MPa, then the coal gas is continuously introduced at the same flow velocity, and simultaneously an absorbent (choline chloride with the mass fraction of 15 percent and the specific surface area of 600 m) is introduced²The graphene oxide mass concentration of 0.01% per g and the water mass fraction of 84.99%) are delivered to the absorption tower 03 at a flow rate of (5000 kg/h, 10000kg/h, 20000kg/h, 50000kg/h, 100000 kg/h) and sprayed into the tower from a nozzle at the upper part in the tower. In the process, the pressure in the tower is maintained at 1.2MPa and the temperature is kept at 35 ℃, so that the coal gas is fully contacted with the absorbent to remove carbon dioxide in the coal gas.

The absorbent coming out from the bottom of the absorption tower 03 is flashed by a flash tank 05 (with the pressure of 0.2MPa and the temperature of 30 ℃), and the separated carbon dioxide is sent to the next working procedure for later use. The liquid at the bottom of the tank is pressurized by a booster pump 06 and then is conveyed to a desorption tower 07 (at the temperature of 70 ℃, under normal pressure) for heat treatment and regeneration, and carbon dioxide in the liquid is further desorbed. The tower bottom liquid is sent to an absorption liquid storage tank 08 for cooling and recycling.

The content of each main component in the outlet gas of the absorption tower is detected and analyzed under the condition of different mass flow rates of the absorbent, and the content (volume fraction) of each main component is shown in the following table.

Under the condition of constant gas flow and pressure in the absorption tower, the mass fraction of choline chloride is 15 percent, and the specific surface area is 600m²The absorbent with 0.01 percent of graphene oxide mass fraction per gram is used for separating carbon dioxide in blast furnace gas.