Efficient and stable carbon dioxide absorbent and application

Abstract

The invention belongs to the field of carbon dioxide capture, and particularly relates to an efficient and stable carbon dioxide absorbent which comprises the following components in percentage by mass: 80-99% of a main absorbent; the mass percentage of the auxiliary absorbent is 1-15%; the mass percent of the antioxidant is 0.01-0.5%; the mass percent of the corrosion inhibitor is 0.01-0.5%; the mass percent of the defoaming agent is 0.01%-0.1%; when the absorbent disclosed by the invention is used under normal pressure, the temperature for absorbing carbon dioxide is-25 DEG C to 75 DEG C, and the desorption temperature of the carbon dioxide is 80 DEG C to 115 DEG C; during field use, the absorbent and water are mixed according to the mass ratio of 1: (2-4); the regeneration energy consumption of the carbon capture agent is reduced, the solution loss is reduced, the carbon capture efficiency is high, the stable absorption-desorption cycle is achieved, and the method can be applied to the field of carbon capture of blast furnace flue gas in the industries such as iron and steel smelting.

Description

Technical Field

[0001] The invention relates to a highly efficient and stable carbon dioxide absorbent. Background Art

[0002] As an important part of carbon capture, utilization and storage (CCUS) technology, it has received extensive attention and research.

[0003] Traditional carbon dioxide absorbents mainly include physical absorbents and chemical absorbents. Physical absorbents mainly use solvents to capture the solubility of carbon dioxide, but they usually have problems such as limited absorption capacity, low selectivity, and high regeneration energy consumption. Chemical absorbents, especially amine-based absorbents, show good absorption effects due to their high reactivity with carbon dioxide. However, this type of absorbent also faces challenges such as high energy consumption, equipment corrosion, and absorbent degradation during the regeneration process. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a highly efficient and stable carbon dioxide absorbent in view of the shortcomings of the above-mentioned prior art, which has the advantages of low regeneration energy consumption, small solution loss, high absorption efficiency, etc., and is suitable for capturing carbon dioxide from blast furnace flue gas such as steel smelting.

[0005] The technical solution of the present invention to solve the above technical problems is: a highly efficient and stable carbon dioxide absorbent, which comprises the following components by mass percentage: Main absorbent: 80-99%; Auxiliary absorbent: 1-15%; Antioxidant: 0.01~0.5%; Corrosion inhibitor: 0.01~0.5%; Defoaming agent: 0.01%~0.1%; Surfactant: 0-0.1%; The sum of the mass percentages of the above components is 100%.

[0006] The technical solution further defined in the present invention is: Preferably, the main absorbent includes one or more of monoethanolamine, diethanolamine, triethanolamine, hydroxyethylethylenediamine, N-methyldiethanolamine, methylethanolamine, diisopropanolamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, wherein the content of any one component cannot be less than 10% when multiple components are present.

[0007] Preferably, the auxiliary absorbent includes compounds such as piperazine, imidazoline, amino acid salts, and ionic liquids that can synergistically improve the carbon dioxide absorption capacity.

[0008] Preferably, the antioxidant is one or more of sodium sulfite, potassium sulfite, ammonium sulfite or ammonium nitrite.

[0009] Preferably, the corrosion inhibitor is an oxidizing corrosion inhibitor or a surface adsorption corrosion inhibitor.

[0010] Preferably, the oxidizing corrosion inhibitor is molybdate or tungstate; and the surface adsorption corrosion inhibitor is dodecylamine or octadecylamine.

[0011] Preferably, the defoaming agent is polyethylene glycol or dimethyl silicone oil.

[0012] Preferably, the surfactant is sodium dodecylbenzene sulfonate or sodium dodecyl sulfate.

[0013] Preferably, in the application of the highly efficient and stable carbon dioxide absorbent, when the absorbent is used under normal pressure, the carbon dioxide absorption temperature is -25°C to 75°C, and the carbon dioxide desorption temperature is 80°C to 115°C.

[0014] Preferably, in the application of the highly efficient and stable carbon dioxide absorbent, when the absorbent is used on site, it is mixed with water in a mass ratio of 1:2-4.

[0015] The absorbent of the present invention is a transparent or translucent liquid, which may gradually turn red due to the catalytic effect of metal ions as the storage time increases.

[0016] The beneficial effects of the present invention are: When the absorbent of the present invention is used under normal pressure, the temperature for absorbing carbon dioxide is -25°C to 75°C, and the temperature for desorbing carbon dioxide is 80°C to 115°C; when used on site, the absorbent and water are mixed at a mass ratio of 1:2-4; the present invention can reduce the regeneration energy consumption of the carbon capture agent and reduce the solution loss, has high carbon capture efficiency and a stable absorption-desorption cycle, and can be applied to the field of carbon capture of blast furnace flue gas in industries such as steel smelting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the carbon dioxide cyclone absorption device in Example 1. DETAILED DESCRIPTION Example

[0018] This embodiment provides a highly efficient and stable carbon dioxide absorbent, which comprises the following components by mass percentage: Main absorbent: monoethanolamine 60%, N-methyldiethanolamine 38.97%; Auxiliary absorbent: piperazine 1%; Antioxidant: sodium sulfite 0.01%; Corrosion inhibitor: sodium vanadate 0.01%; Defoaming agent: polyethylene glycol 0.01%; The sum of the mass percentages of the above components is 100%.

[0019] Embodiment 2: The total mass of a highly efficient and stable carbon dioxide absorbent is 100%, and the components and their mass percentages are as follows: Main absorbent: monoethanolamine 60%, N-methyldiethanolamine 22.8%; Auxiliary absorbent: piperazine 15% Antioxidant: sodium sulfite 0.5%; Corrosion inhibitor: sodium vanadate 0.5%; Defoaming agent: dimethyl silicone oil 0.1%; Surfactant: sodium dodecylbenzene sulfonate 0.1%; The sum of the mass percentages of the above components is 100%.

[0020] Embodiment 3: The total mass of a highly efficient and stable carbon dioxide absorbent is 100%, and the components and their mass percentages are as follows: Main absorbent: N-methyldiethanolamine 60%, monoethanolamine 20%; Auxiliary absorbent: piperazine 10%; Antioxidant: potassium sulfite 0.5%; Corrosion inhibitor: sodium vanadate 0.5%; Defoaming agent: polyethylene glycol 0.1%.

[0021] Surfactant: sodium dodecyl sulfate 0.1%; The sum of the mass percentages of the above components is 100%.

[0022] Embodiment 4: Monoethanolamine and the carbon dioxide absorbents prepared in Examples 1 to 3 were mixed with water at a mass ratio of 1:2-4, respectively, to prepare samples 1#2, 1#3, 1#4; 2#2, 2#3, 2#4; 3#2, 3#3, 3#4. The working conditions were: gas-liquid ratio of 200, absorption temperature of 25°C, regeneration temperature of 110°C, and the carbon dioxide capture performance of the samples was tested using a cyclone absorption regeneration process device. At the same time, the corrosion rate of the absorbent mixed solution on the carbon dioxide absorption regeneration device, the energy consumption of regeneration, and the solution loss of the samples were tested.

[0023] The above carbon dioxide cyclone absorption device, such as Figure 1 As shown, it includes a cyclone absorber 3, a cyclone absorption tower 4, a rich liquid pump 5; a plate heat exchanger 6, a water cooler 7, a lean liquid pump 8, a cyclone regenerator 9, a cyclone regeneration tower 10, a reboiler 11, a regeneration circulation pump 12 and a condensing device 13; The cyclone absorber 3 and the cyclone regenerator 9 are respectively arranged inside the cyclone absorber 4 and the cyclone regeneration tower 10; the cyclone absorber 3 is respectively installed with the above-mentioned sample absorbent to be tested in sequence, and a flue gas pipeline is arranged on one side of the top of the cyclone absorber 4, and the outlet of one side of the bottom end of the cyclone absorber 4 is connected to the inlet end of the rich liquid pump 5, and the outlet end of the rich liquid pump 5 is connected to the inlet end of the top end of the cyclone regeneration tower 10 through the plate heat exchanger 6, and the bottom end of the cyclone regeneration tower 10 is connected to the water cooler 7 through the plate heat exchanger 6, and the water cooler 7 is connected to the cyclone absorber 4 through the lean liquid pump; The bottom side of the cyclone regeneration tower 10 is connected to a reboiler 11, and the reboiler is connected to the upper end of the cyclone regeneration tower 10 through a regeneration circulation pump. The top of the cyclone regeneration tower 10 is connected to a reflux tank through a condensing device 13, and the reflux tank 15 is connected to the upper end of the cyclone regeneration tower 10 through a reflux pump.

[0024] Flue gas with a carbon dioxide volume fraction of 18% is introduced from the upper end of the cyclone absorption tower 4 through the flue gas duct 2. The absorbent in the cyclone absorption tower 4 performs cyclone absorption on the carbon dioxide in the flue gas at normal pressure and 25°C. The solution after absorbing the carbon dioxide is a rich liquid. It enters the cyclone regeneration tower 10 through the heat exchanger 6, is heated by the reboiler 11, and is regenerated at normal pressure and 110°C. The solution after desorbing the carbon dioxide is a lean liquid. The desorbed carbon dioxide is discharged from the top of the cyclone regeneration tower 10. The lean liquid then enters the absorption tower 4 through the heat exchanger 6, and cyclically absorbs the carbon dioxide in the flue gas.

[0025] The carbon dioxide absorption device is in continuous operation. The infrared carbon dioxide concentration analyzer is used to detect the carbon dioxide concentration in the flue gas 1 at the upper end of the cyclone collection tower 4 and the gas discharged from the top of the cyclone regeneration tower 10, and the carbon capture efficiency of the sample is calculated. The calculation formula is: Absorption efficiency = (inlet CO2 concentration - outlet CO2 concentration) / inlet CO2 concentration.

[0026] At the top outlet of the cyclone regeneration tower 10, the CO2 production is detected, and the flow rate and temperature of the steam are read by a flow meter and a thermometer at the bottom of the regeneration tower 10, so that the steam consumption per unit CO2 production can be obtained.

[0027] The hanging sheet method is adopted in the pipeline through which the rich liquid flows, and a steel sheet made of the same material as the equipment is hung. The weight loss of the steel sheet is tested regularly to obtain the corrosion rate of the sample, which is expressed in mm / year.

[0028] The loss of the sample was measured based on the amount of solution consumed per unit CO2 production, that is, a fixed volume of solution was added every day to maintain the solution equivalent concentration unchanged, and then the total CO2 production was recorded each day. The loss of solution was obtained by dividing the amount of added solution by the total CO2 production.

[0029] The performance of each sample was tested, and the test results are shown in Table 1.

[0030] Table 1 Flue gas decarbonization performance In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A highly efficient and stable carbon dioxide absorbent, characterized in that: The following components are included by mass percentage: Main absorbent: 80-99%; Auxiliary absorbent: 1-15%; Antioxidant: 0.01~0.5%; Corrosion inhibitor: 0.01~0.5%; Defoaming agent: 0.01%~0.1%; Surfactant: 0-0.1%; The sum of the mass percentages of the above components is 100%.

2. A highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The main absorbent includes one or more of monoethanolamine, diethanolamine, triethanolamine, hydroxyethylethylenediamine, N-methyldiethanolamine, methylethanolamine (MMEA), diisopropanolamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, wherein any one component cannot be less than 10% when multiple components are present.

3. The highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The auxiliary absorbent includes compounds such as piperazine, imidazoline, amino acid salt, ionic liquid, etc., which can synergistically improve the carbon dioxide absorption capacity.

4. The highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The antioxidant includes sodium sulfite, potassium sulfite, ammonium sulfite or ammonium nitrite.

5. The highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The corrosion inhibitor is an oxidizing corrosion inhibitor or a surface adsorption corrosion inhibitor.

6. A highly efficient and stable carbon dioxide absorbent according to claim 57, characterized in that: The oxidizing corrosion inhibitor is molybdate or tungstate; the surface adsorption corrosion inhibitor is dodecylamine or octadecylamine.

7. The highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The defoaming agent is polyethylene glycol or dimethyl silicone oil.

8. The highly efficient and stable carbon dioxide absorbent according to claim 1, characterized in that: The surfactant is sodium dodecylbenzene sulfonate or sodium dodecyl sulfate.

9. Use of a highly efficient and stable carbon dioxide absorbent according to any one of claims 1 to 8, characterized in that: When the absorbent is used under normal pressure, the temperature for absorbing carbon dioxide is -25°C to 75°C, and the temperature for desorbing carbon dioxide is 80°C to 115°C.

10. Use of a highly efficient and stable carbon dioxide absorbent according to any one of claims 1 to 8, characterized in that: When the absorbent is used on site, it is mixed in a mass ratio of absorbent to water of 1:2-4.

Images