Low-water-content absorbent for capturing low-concentration CO2 as well as preparation and application of low-water-content absorbent

Abstract

The invention relates to a low-water-content absorbent for capturing low-concentration CO2 as well as preparation and application of the low-water-content absorbent, and belongs to the technical field of waste gas treatment. The absorbent is prepared from the following components in percentage by mass: 10 to 20 percent of monoethanolamine, 10 to 20 percent of 2-amino-2-methyl-1-propanol, 40 to 60 percent of diethylene glycol monomethyl ether and 10 to 30 percent of water, wherein the total mass of the raw materials is 100 percent; the components of the raw materials are uniformly mixed to obtain a homogeneous solution, namely the absorbent. The absorbent is a novel decarburization low-water type absorbent, a high-boiling physical solvent diethylene glycol monomethyl ether is adopted to replace most fresh water, on one hand, latent heat of vaporization in the absorbent regeneration process is reduced, regeneration energy consumption is further reduced, on the other hand, consumption of fresh water is greatly reduced, and long-term stable operation of a carbon capture system is facilitated; meanwhile, through the efficient synergistic effect with components such as alkylol amine and the like, efficient and low-consumption trapping of carbon dioxide in ship tail gas in a low-concentration environment is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-water absorbent for low-concentration CO2 capture and its preparation and application, in particular to a low-water absorbent for low-concentration carbon dioxide capture of ship exhaust gas, belonging to the technical field of waste gas treatment. BACKGROUND

[0002] Carbon capture and storage technology (CCS) is an effective way to achieve carbon emission reduction in the shipping industry, and carbon capture absorbent, as its core material, plays an important role in it. At present, the disclosed carbon capture absorbent related patents mainly use alcohol amine aqueous solution and inorganic alkali aqueous solution, such as: the Chinese patent application with the application number CN201410621722.9 discloses a method and device for recycling carbon dioxide in ship diesel engine exhaust gas, wherein the carbon capture absorbent is ethanol amine solution; the patent application with the publication number CN118491261A discloses a composite absorbent for capturing low-concentration carbon dioxide in ship exhaust gas, which to some extent overcomes the problem of high energy consumption in the regeneration of ethanol amine absorbent. The above-mentioned carbon capture absorbents are prepared by using water, which consumes a large amount of fresh water. On the one hand, the vaporization of water in the absorbent regeneration process consumes a large amount of energy, causing energy waste, and on the other hand, the lack of fresh water on the ship is not conducive to the long-term stable operation of the carbon capture system. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a low-water absorbent for low-concentration CO2 capture and its preparation and application. The absorbent is a new type of decarbonization low-water absorbent, which is characterized by using a high-boiling physical solvent to replace most of the fresh water. On the one hand, it reduces the latent heat of vaporization in the absorbent regeneration process, further reducing the regeneration energy consumption, and on the other hand, it greatly reduces the consumption of fresh water, facilitating the long-term stable operation of the carbon capture system. At the same time, through the efficient synergistic effect with components such as alcohol amine, efficient and low-consumption capture of carbon dioxide in low-concentration environment, such as ship exhaust gas, is achieved. To achieve the purpose of the present application, the following technical solutions are provided.

[0004] A low-water absorbent for low-concentration CO2 capture, wherein the total mass of the raw materials is 100%, and the mass fraction of each component is as follows: Ethanol amine (MEA) 10% ~ 20%, 2 Amino 2 Methyl 1 Propyl alcohol (AMP) 10% ~ 20%, Diethylene glycol monomethyl ether (DEGME) 40% ~ 60%, Water (H2O) 10% ~ 30%.

[0005] Further, the absorbent further comprises a cyclic amine, the cyclic amine being piperazine (PZ) or morpholine (MA), preferably piperazine; Further, preferably, the absorbent, with the total mass of its raw materials being 100%, has a mass fraction of the cyclic amine of 2% ~ 5%.

[0006] Further, a low-water absorbent for low-concentration CO2 capture, the absorbent, with the total mass of its raw materials being 100%, has the following components and mass fractions: Monoethanolamine (MEA) 10% ~ 20%, 2 Amino 2 Methyl 1 Propanol (AMP) 10% ~ 20%, Cyclic amine 2% ~ 5%, Diethylene glycol monomethyl ether (DEGME) 40% ~ 60%, Water (H2O) 10% ~ 30%.

[0007] A preparation method of the low-water absorbent for low-concentration CO2 capture according to the present application, the method being: mixing the components of the raw materials uniformly to obtain a homogeneous solution, which is a low-water absorbent for low-concentration CO2 capture.

[0008] An application of the low-water absorbent for low-concentration CO2 capture according to the present application, the application being: the absorbent is used to capture CO2 in a CO2 capture device, and the absorbent is still a homogeneous solution after capturing CO2 and does not separate into phases or generate precipitates.

[0009] Further, the application is: the absorbent is countercurrently contacted with a CO2-containing gas to capture and absorb CO2, the formed absorption solution is transported to a regeneration tower for heating and regeneration, the obtained regenerated solution is transported to an absorption tower for absorption, and the cycle is used; Further, the CO2-containing gas is a ship exhaust gas; The absorption temperature of the absorption tower is usually 20 ℃ ~ 60 ℃; The regeneration temperature of the regeneration tower is 100 ℃ ~ 120 ℃.

[0010] Advantages (1) The present application provides a kind of low concentration CO2 capture of little water absorbent, the raw material component of the absorbent contains the mass fraction of 40% ~ 60% diethylene glycol monomethyl ether, it is a high boiling physical solvent, on the one hand, the heat consumption of vaporization in the absorbent regeneration process is reduced, and further reduce the regeneration energy consumption, on the other hand, the consumption of fresh water is greatly reduced, which is convenient for long-term stable operation of carbon capture system; (2) The present application provides a kind of low concentration CO2 capture of little water absorbent, the raw material component of the absorbent also contains the mass fraction of 10% ~ 20% monoethanolamine and the mass fraction of 10% ~ 20% 2 Amino 2 Methyl 1 Propyl alcohol, so that the intermediate produced after absorbing CO2 can exist stably in the system, and phase separation and precipitation are not generated; (3) The present application provides a kind of low concentration CO2 capture of little water absorbent, the raw material component of the absorbent also contains the mass fraction of 10% ~ 30% little water, the presence of water ensures the stability of the system, and phase separation and precipitation are not generated, while the viscosity of the absorbent system can be reduced; (4) The present application provides a kind of low concentration CO2 capture of little water absorbent, the raw material component of the absorbent can also further include cyclic amine piperazine or morpholine, which acts to produce a synergistic effect with the aforementioned alcohol amine molecules, and can improve the absorption effect of the absorbent on CO2; (5) The present application provides a kind of low concentration CO2 capture of little water absorbent, the raw material component of the absorbent preferably uses cyclic amine as piperazine, compared with morpholine, piperazine is solid in physical properties, not easy to volatilize and has lighter odor;Further, due to its relatively high price, the comprehensive cost and the stability of the absorbent system, the mass fraction is preferably 2% ~ 5%; (6) The present application provides a kind of low concentration CO2 capture of little water absorbent, compared with the traditional water-based MEA absorbent, the relative value of CO2 absorption efficiency is increased by more than 20%, and the relative value of regeneration energy consumption is reduced by 40%; compared with the composite amine absorbent disclosed in Chinese patent application No. CN118491261A, the CO2 absorption efficiency can be increased to more than 95%. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a schematic diagram of the continuous absorption and regeneration test device described in the examples and comparative examples. DETAILED DESCRIPTION

[0012] In order to enable a detailed understanding of the technical features and content of the present application, the preferred embodiments of the present application will be described in more detail below. Although the preferred embodiments of the present application are described in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0013] In the following examples: The performance testing device and method of the absorbent described in the examples and comparative examples are as follows: The absorbent is injected into a continuous absorption and regeneration testing device as shown in Figure 1 , and performance testing is carried out. The testing device is composed of a gas distribution system, an absorption tower, a CO2 infrared analyzer, a mass transfer pump, a regeneration tower, an electric heater, a wet flowmeter and a heat exchanger, etc. Among them, the gas distribution system is composed of a fan, a CO2 mass flowmeter and a gas mixing tank, etc. to simulate the configuration of ship exhaust gas with a CO2 volume fraction of 4% ~ 5%; the absorption of CO2 in the ship exhaust gas is completed in the absorption tower, the gas at the inlet / outlet of the absorption tower is connected with the CO2 infrared analyzer through a measuring line to measure the CO2 volume fraction φ in at the inlet of the absorption tower and the CO2 volume fraction φ out at the outlet of the absorption tower, which are used to calculate the absorption efficiency of CO2; the absorbed absorbent (i.e. rich liquid) is transported to the regeneration tower by a rich liquid pump, the electric heater is installed in the tower kettle of the regeneration tower to regenerate the rich liquid, the regenerated absorbent (i.e. lean liquid) is transported to the absorption tower by a lean liquid pump for absorption with the absorbent; the heating temperature / heating power (P) of the regeneration tower can be adjusted and measured by a pressure regulator and a high-precision electric meter respectively, the high-precision electric meter can accumulate the electric energy (E) consumed in the regeneration process, the volume (V) of the regenerated CO2 is measured by a wet flowmeter, which is used to calculate the regeneration energy consumption; the lean liquid and the rich liquid exchange heat through the heat exchanger. The specific parameters are shown in Table 1.

[0014] Table 1

[0015] Among them,

[0016] The viscosity testing method of the absorbent described in the examples and comparative examples is as follows: A NDJ-9S digital rotary viscometer from Shanghai Fangrui Instrument Co., Ltd. is used for measurement, the absorbent is loaded into the sample barrel, the start button is clicked for testing, and the viscosity value displayed on the instrument screen is read after the test is completed.

[0017] Example 1 A low-concentration CO2 capture absorbent with little water, the absorbent is 100% based on the total mass of 5 kg of its raw materials, wherein each component and its mass fraction are as follows: Monoethanolamine (MEA) 10%, 2 Amino 2 Methyl 1 Propanol (AMP) 20%, diethylene glycol monomethyl ether (DEGME) 40%, water (H2O) 30%; The various components of the raw materials are mixed uniformly to obtain a homogeneous solution, that is, a low-water absorbent for low-concentration carbon dioxide capture, referred to as No. 1 absorbent.

[0018] The No. 1 absorbent prepared in this embodiment is tested, and the test results are as follows: the viscosity is 8.4 cP (1) Viscosity The viscosity of the No. 1 absorbent is measured to be 10.4 cP by using a viscometer; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 The performance test is carried out by adding the No. 1 absorbent into the device, controlling the temperature of the No. 1 absorbent to be 40 ℃, and controlling the regeneration temperature of the regeneration tower to be 110 ℃. Through the collection of inlet and outlet CO2 concentration data, the CO2 absorption efficiency is calculated to be 80.7%, and the regeneration energy consumption is calculated to be 4.1 kJ / g CO2.

[0019] Example 2 A low-water absorbent for low-concentration CO2 capture, wherein the total mass of the raw materials is 100%, and the various components and their mass fractions are as follows: MEA 10%, AMP 20%, DEGME 50%, H2O 20%; The various components of the raw materials are mixed uniformly to obtain a homogeneous solution, that is, a low-water absorbent for low-concentration carbon dioxide capture, referred to as No. 2 absorbent.

[0020] The No. 2 absorbent prepared in this embodiment is tested as follows: (1) Viscosity The viscosity of the No. 2 absorbent is measured to be 12.1 cP by using a viscometer; (2) CO2 absorption efficiency and regeneration energy consumption The performance test is carried out by adding the No. 2 absorbent into the continuous absorption and regeneration test device as shown in Figure 1 The temperature of the No. 2 absorbent is controlled to be 40 ℃, and the regeneration temperature of the regeneration tower is controlled to be 110 ℃. Through the collection of inlet and outlet CO2 concentration data, the CO2 absorption efficiency is calculated to be 83.1%, and the regeneration energy consumption is calculated to be 4.0 kJ / g CO2.

[0021] Example 3 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials, wherein each component and its mass fraction are as follows: MEA 10%, AMP 20%, DEGME 60%, H2O 10%; Mixing each component of the raw materials uniformly to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration carbon dioxide capture, referred to as No. 3 absorbent.

[0022] The No. 3 absorbent prepared in this example is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 3 absorbent is measured to be 15.3 cP by using a viscometer; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the No. 3 absorbent is controlled to be 40 ℃, the regeneration temperature of the regeneration tower is 110 ℃, and the CO2 absorption efficiency is calculated to be 84.6% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is 3.9 kJ / g CO2.

[0023] Example 4 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials, wherein each component and its mass fraction are as follows: MEA 15%, AMP 15%, DEGME 50%, H2O 20%; Mixing each component of the raw materials uniformly to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration carbon dioxide capture, referred to as No. 4 absorbent.

[0024] The No. 4 absorbent prepared in this example is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 4 absorbent is measured to be 11.7 cP by using a viscometer; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the No. 4 absorbent is controlled to be 40 ℃, the regeneration temperature of the regeneration tower is 110 ℃, and the CO2 absorption efficiency is calculated to be 89.1% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is 3.7 kJ / g CO2.

[0025] Example 5 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials thereof, wherein each component and its mass fraction are as follows: MEA 20%, AMP 10%, DEGME 50%, H2O 20%; Each component of the raw materials is mixed uniformly to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration CO2 capture, referred to as No. 5 absorbent for short.

[0026] The No. 5 absorbent prepared in this embodiment is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 5 absorbent is measured by using a viscometer, and the viscosity is 12.2 cP; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the No. 5 absorbent is controlled to be 40 ℃, the regeneration temperature of the regeneration tower is controlled to be 110 ℃, and the CO2 absorption efficiency is calculated by collecting the inlet and outlet CO2 concentration data to be 88.4%, and the regeneration energy consumption is 3.8 kJ / g CO2.

[0027] Example 6 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials thereof, wherein each component and its mass fraction are as follows: MEA 15%, AMP 10%, piperazine (PZ) 5%, DEGME 50%, H2O 20%; Each component of the raw materials is mixed uniformly to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration CO2 capture, referred to as No. 6 absorbent for short.

[0028] The No. 6 absorbent prepared in this embodiment is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 6 absorbent is measured by using a viscometer, and the viscosity is 12.6 cP; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the No. 6 absorbent is controlled to be 40 ℃, the regeneration temperature of the regeneration tower is controlled to be 110 ℃, and the CO2 absorption efficiency is calculated by collecting the inlet and outlet CO2 concentration data to be 95.7%, and the regeneration energy consumption is 3.4 kJ / g CO2.

[0029] Example 7 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials thereof, wherein each component and its mass fraction are as follows: MEA 15%, AMP 13%, PZ 2%, DEGME 50%, H2O 20%; The raw materials are mixed to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration CO2 capture, referred to as No. 7 absorbent.

[0030] The No. 7 absorbent prepared in this embodiment is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 7 absorbent is measured by a viscometer to be 11.9 cP; (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform the performance test as follows: The temperature of the No. 7 absorbent is controlled to be 40 ℃, and the regeneration temperature of the regeneration tower is controlled to be 110 ℃, and the CO2 absorption efficiency is calculated to be 94.5% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is calculated to be 3.5 kJ / g CO2; The temperature of the No. 7 absorbent is controlled to be 20 ℃, and the regeneration temperature of the regeneration tower is controlled to be 110 ℃, and the CO2 absorption efficiency is calculated to be 95.3% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is calculated to be 3.4 kJ / g CO2; The temperature of the No. 7 absorbent is controlled to be 60 ℃, and the regeneration temperature of the regeneration tower is controlled to be 110 ℃, and the CO2 absorption efficiency is calculated to be 90.8% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is calculated to be 3.7 kJ / g CO2; The temperature of the No. 7 absorbent is controlled to be 40 ℃, and the regeneration temperature of the regeneration tower is controlled to be 100 ℃, and the CO2 absorption efficiency is calculated to be 86.6% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is calculated to be 3.2 kJ / g CO2; The temperature of the No. 7 absorbent is controlled to be 40 ℃, and the regeneration temperature of the regeneration tower is controlled to be 120 ℃, and the CO2 absorption efficiency is calculated to be 96.9% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is calculated to be 3.8 kJ / g CO2.

[0031] Example 8 A low-water absorbent for low-concentration CO2 capture, the absorbent being 100% based on the total mass of 5 kg of raw materials thereof, wherein each component and its mass fraction are as follows: MEA 15%, AMP 13%, PZ 2%, DEGME 50%, H2O 20%; The various components of the raw materials are mixed uniformly to obtain a homogeneous solution, i.e., a low-water absorbent for low-concentration carbon dioxide capture, referred to as No. 8 absorbent.

[0032] The No. 8 absorbent prepared in this example is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 8 absorbent is measured to be 12.2 cP using a viscometer. (2) CO2 absorption efficiency and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the No. 8 absorbent is controlled to be 40°C, the regeneration temperature of the regeneration tower is 110°C, and the CO2 absorption efficiency is calculated to be 93.4% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is 3.6 kJ / g CO2.

[0033] Comparative Example 1 An absorbent MEA solution, the absorbent is 100% based on the total mass of the raw materials thereof 5 kg, wherein the various components and their mass fractions are as follows: MEA 30%, H2O 70%; The various components of the raw materials are mixed uniformly to obtain an absorbent MEA.

[0034] The absorbent MEA prepared in this example is subjected to the following performance tests: (1) Viscosity The viscosity of the absorbent MEA solution is measured to be 3.9 cP using a viscometer. (2) CO2 absorption efficiency The continuous absorption and regeneration test device as shown in Figure 1 is added to perform performance tests, the temperature of the absorbent MEA is controlled to be 40°C, the regeneration temperature of the regeneration tower is 105°C, and the CO2 absorption efficiency is calculated to be 71.4% by collecting the inlet and outlet CO2 concentration data, and the regeneration energy consumption is 6.4 kJ / g CO2.

[0035] Comparative Example 2 An absorbent, the absorbent is 100% based on the total mass of the raw materials thereof 5 kg, wherein the various components and their mass fractions are as follows: MEA 10%, AMP 20%, H2O 70%; The various components of the raw materials are mixed uniformly to obtain an absorbent, referred to as No. 9 absorbent.

[0036] The No. 9 absorbent prepared in this example is subjected to the following performance tests: (1) Viscosity The viscosity of the No. 9 absorbent was measured to be 3.8 cP by a viscometer; (2) Absorption efficiency of CO2 and regeneration energy consumption The continuous absorption and regeneration test device as shown in Figure 1 was added to perform performance test, the temperature of the No. 9 absorbent was controlled to be 40 ℃, the regeneration temperature of the regeneration tower was 105 ℃, the absorption efficiency of CO2 was calculated to be 75.4% by collecting the CO2 concentration data at the inlet and outlet, and the regeneration energy consumption was 4.9 kJ / g CO2.

[0037] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A low-water absorbent for capturing low-concentration CO2, characterized in that: The absorbent is based on the total mass of its raw materials (100%), and the components and their mass fractions are as follows: Monoethanolamine 10% ~ 20%, 2 amino 2 methyl 1 Propanol 10% ~ 20%, Diethylene glycol monomethyl ether 40% ~ 60%, Water content: 10% to 30%.

2. The low-water absorbent for capturing low-concentration CO2 according to claim 1, characterized in that: The absorbent also includes piperazine or morpholine.

3. The low-water absorbent for capturing low-concentration CO2 according to claim 1, characterized in that: The absorbent also includes piperazine.

4. A low-water absorbent for capturing low-concentration CO2 according to claim 2 or 3, characterized in that: Based on the total mass of the absorbent raw material as 100%, the mass fraction of cyclic amines is 2% to 5%.

5. A method for preparing a low-water absorbent for capturing low-concentration CO2 as described in any one of claims 1 to 4, characterized in that: The various components of the raw materials are mixed evenly to obtain a homogeneous solution, which is a low-water absorbent for capturing low-concentration carbon dioxide.

6. The application of a low-water absorbent for capturing low-concentration CO2 as described in any one of claims 1 to 4, characterized in that: The absorbent is used in a carbon dioxide capture device to capture and absorb CO2.

7. The application of a low-water absorbent for capturing low-concentration CO2 according to claim 6, characterized in that: The absorbent comes into countercurrent contact with CO2-containing gas to capture and absorb CO2. The resulting absorbent solution is transported to a regeneration tower for heating and regeneration, and the resulting regenerated liquid is transported to an absorption tower for absorption and reuse.

8. The application of a low-water absorbent for capturing low-concentration CO2 according to claim 6 or 7, characterized in that: The gas containing CO2 is ship exhaust.

9. The application of a low-water absorbent for capturing low-concentration CO2 according to claim 7, characterized in that: The absorption temperature of the absorption tower is 20 ℃~60 ℃, and the regeneration temperature of the regeneration tower is 100 ℃~120 ℃.

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