CO2 phase change absorption system and preparation method and application thereof

Abstract

The invention discloses a CO2 phase change absorption system and a preparation method and application thereof, and belongs to the technical field of flue gas purification. The system comprises a main agent and an additive, wherein the main agent comprises a base solution, a phase splitting agent and an activating agent; the additive comprises a volatilization inhibiting agent, an antioxidant and oxide nanoparticles; the base solution is prepared from hydroxyethyl ethylenediamine, diethylaminoethanol and water; glycine is introduced into the CO2 phase change absorption system as a volatile inhibiting agent, so that the volatility of the whole system can be reduced; sodium potassium tartrate tetrahydrate or antimony potassium tartrate tetrahydrate is introduced as an antioxidant, so that the oxidation resistance of the whole system is improved, the precipitation of ammonium salt is reduced, and the corrosion and oxidation of the whole system to equipment are reduced; and the CO2 desorption capability of the system is improved by introducing the oxide nanoparticles.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas purification, and in particular relates to a CO2 phase change absorption system and a preparation method and application thereof. Background Art

[0002] CCUS (Carbon Capture, Utilization and Storage) technology is a new development trend of CCS (Carbon Capture and Storage) technology. It refers to the capture and purification of CO2 (carbon dioxide) from industrial emission sources (such as large power plants, steel mills, chemical plants, etc.) or the air, and then its use or storage to reduce the concentration of greenhouse gases in the atmosphere and mitigate the impact of climate change. Compared with CCS, CCUS, in addition to capture and storage, also includes the use of captured CO2 as a resource to convert it into valuable products, such as carbon utilization in chemical production, fuel synthesis, and building materials. Therefore, in practical applications, CCUS is regarded as a more comprehensive and integrated carbon emission reduction solution.

[0003] Since the combustion of coal is one of the main sources of CO2 emissions, the transformation of the energy structure is continuously promoted in this field, the proportion of coal is reduced, and the use of clean energy is increased to reduce CO2 emissions. Therefore, CCUS, as an emerging technology that can achieve large-scale reductions in greenhouse gas emissions, is highly valued. Among them, CO2 capture technology is the most critical link in CCUS that determines the purity and cost of CO2 resource utilization, but its process energy consumption accounts for more than 60% of the total energy consumption of CCUS projects. Therefore, it is crucial to develop new high-load, low-energy regenerable CO2 absorbents to reduce energy consumption, and it is also a key technical bottleneck problem for the large-scale promotion of CCUS.

[0004] Methods for capturing CO2 from low-partial-pressure flue gas include chemical absorption, solid adsorption, membrane separation, and cryogenic separation. Among them, chemical absorption is the most commonly chosen flue gas CO2 capture method for CCUS projects due to its technical maturity and application prospects.

[0005] The chemical absorption method is a method of separating CO2 from other gases by selectively reacting the absorbent with CO2 in the mixed flue gas, and CO2 can be regenerated by the reverse reaction of the reaction, releasing high-purity CO2 for enrichment. Among them, the chemical solvent absorption method in the chemical absorption method is the only technology that has entered industrial-scale trials. It eliminates the need to transform existing combustion technology and related facilities, and can directly use liquid solvents to capture and separate CO2. Since the 1930s, chemical absorbents used in CO2 capture technology have been continuously innovated. In research, phase change absorbents (two-phase absorbents), low-water absorbents and ionic liquids have been introduced instead of single or multi-composite amine absorbents. Because ionic liquids have too high viscosity, high energy consumption, and high cost, they are temporarily difficult to industrialize. Therefore, phase change absorbents and low-water absorbents have become research hotspots.

[0006] Phase change absorbents are divided into two categories: one is an absorption system that undergoes stratification after absorption (first-type phase change absorption system), and the other is an absorption system that undergoes stratification after desorption (second-type phase change absorption system). Regeneration energy consumption is reduced by reducing the amount of regeneration liquid. However, existing phase change absorbents are prone to oxidation and corrosion of equipment, which increases overall energy consumption. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a CO2 phase change absorption system and its preparation method and application, so as to solve the problem that the phase change absorbent in the prior art is easy to oxidize and corrode equipment, consumes high energy, and makes the CO2 capture cost high.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions: A CO2 phase change absorption system, comprising a main agent and an additive; the main agent comprises a base liquid, a phase separation agent and an activator; the additive comprises a volatility suppressant, an antioxidant and oxide nanoparticles; The base liquid consists of hydroxyethylethylenediamine, diethylaminoethanol and water; The volatility suppressant is glycine; The antioxidant contains at least sodium potassium tartrate or potassium antimony tartrate.

[0009] A further improvement of the present invention is: Preferably, the antioxidant further contains any one or both of ethylenediaminetetraacetic acid or sodium sulfite.

[0010] Preferably, the phase separation agent is n-butanol.

[0011] Preferably, the activator is 2-amino-2-methyl-1-propanol.

[0012] Preferably, the mass of the volatility suppressant is 0.2% to 0.85% of the mass of the main agent, the mass of the antioxidant is 0.15% to 0.5% of the mass of the main agent, and the mass of the oxide nanoparticles is 1% to 3% of the mass of the main agent.

[0013] Preferably, in the main agent, the mass fraction of the base liquid is 82% to 85%, the mass fraction of the phase separation agent is 12% to 15%, and the mass fraction of the activator is 1% to 3%.

[0014] Preferably, the sum of the mass fractions of hydroxyethylethylenediamine and diethylaminoethanol in the base liquid is 54% to 58%, and the remainder is water.

[0015] Preferably, the oxide nanoparticles are any one of CuO, Fe3O4, ZnO, SiO2 or Al2O3 in terms of mass fraction.

[0016] A preparation method of the above-mentioned CO2 phase change absorption system is to mix hydroxyethylethylenediamine, diethylaminoethanol, water, a phase separation agent, a volatility suppressant, an activator, an antioxidant and oxide nanoparticles according to a set mass ratio to obtain the CO2 phase change absorption system.

[0017] An application of the above-mentioned CO2 phase change absorption system is used to absorb CO2 in the flue gas of a coal-fired boiler.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a CO2 phase change absorption system, including a base liquid, a phase separation agent, a volatility suppressant, an activator and an antioxidant; wherein the base liquid is composed of hydroxyethylethylenediamine, diethylaminoethanol and water, the volatility suppressant is glycine, and the antioxidant is provided with potassium sodium tartrate or potassium antimony tartrate. The low-water phase change absorbent (water content <50%) of the present invention can achieve liquid phase separation, and thus there is no need to regenerate the entire absorbent solution, and only the rich phase needs to be regenerated. Thereby reducing the regeneration energy consumption and increasing the regeneration rate, having the characteristics of high absorption and desorption rates and low regeneration energy consumption, and can effectively reduce the CO2 capture energy consumption and reduce the CO2 capture cost.

[0019] Based on this composition, the phase change absorbent of the present invention has the following advantages: (1) The base liquid contains hydroxyethylethylenediamine and diethylaminoethanol. The presence of these two substances can make the CO2 phase change absorption system transform into two distinct phases after absorbing CO2. Among them, hydroxyethylethylenediamine, as the main substance absorbing CO2, can form a rich phase as the lower phase, and diethylaminoethanol absorbs CO2 as the upper phase, which is a lean phase. After separating the two, during desorption, only the rich phase needs to be heated, so the amount of heated solution can be effectively reduced, reducing the regeneration energy consumption. At the same time, due to the low thermal melting point of the low-water phase change absorbent, the regeneration energy consumption can be further reduced on the basis of the phase change absorbent.

[0020] (2) The volatility suppressant of the present invention is glycine, which is a salt compound. When it is dissolved in a solvent (such as water), it will increase the boiling point of the solution. This phenomenon is attributed to the fact that the presence of glycine molecules in the solution interferes with the normal interaction between the solvent (water) molecules, resulting in an increase in the energy required for the water molecules to change from liquid to gas (i.e., evaporate). Therefore, the boiling point of the solution will increase compared to the pure solvent, and its volatility will decrease accordingly. According to the principle of Raoult's law, the presence of the solute (here glycine) will reduce the vapor pressure of the solution. Specifically, the glycine molecules will occupy part of the space originally occupied by the solvent molecules (water molecules), thereby reducing the number of solvent molecules on the surface of the solution. Since the vapor pressure is mainly generated by the evaporation of the solvent molecules on the surface of the solution, the reduction in the number of solvent molecules directly leads to a decrease in the vapor pressure, thereby reducing the volatility of the solution. Therefore, after glycine is dissolved in water, it interferes with the interaction between the solvent molecules and increases the energy required for evaporation, as well as reducing the vapor pressure of the solution, which together lead to an increase in the boiling point of the solution and a decrease in volatility. Glycine can also form complexes with amines (hydroxyethylethylenediamine and diethylaminoethanol) in the system and form hydrogen bonds with water, thereby preventing the main substances in the system from being oxidized and degraded, protecting organic amine substances, reducing the loss of substances, and increasing the content of effective ingredients in the entire system, that is, improving the antioxidant degradation ability of the entire system, which is beneficial to the long-term operation of the entire system.

[0021] (3) The antioxidant of the present invention contains at least potassium sodium tartrate or potassium antimony tartrate. Potassium sodium tartrate or potassium antimony tartrate is a weak acid salt, which can dissociate into tartrate ions in water, and can form complexes with hydroxyethylethylenediamine and diethylaminoethanol in the system, and form hydrogen bonds with water, thereby reducing the attack of oxygen free radicals, further reducing the oxidative electrolysis phenomenon, and improving the antioxidant degradation ability of the main substances in the whole system.

[0022] (4) For organic amines, if oxidative degradation occurs, organic salts are easily converted into ammonium salts, which accelerates the corrosion of equipment. Therefore, through the combined action of glycine and antioxidants, the volatilization of the entire system solution and the oxidative degradation of amines can be avoided, thereby reducing the corrosion of the entire system to the equipment.

[0023] (5) The addition of oxide nanoparticles can promote CO2 desorption and increase the amount of CO2 desorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an energy-saving process flow chart of the present invention which uses a CO2 phase change absorption system and is suitable for low partial pressure CO2 capture and purification.

[0025] Among them: 1. Absorption tower; 2. Delivery pump; 3. Two-phase separator; 4. Heater; 5. Heat exchanger; 6. Desorption tower; 7. Flash evaporator; 8. Compressor; 9. Cooler. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0027] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0029] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0030] The first aspect of the present invention discloses a CO2 phase change absorption system, which is particularly suitable for a low-concentration CO2 phase change absorption system in coal-fired boiler flue gas, and includes a main agent and an additive; the main agent includes a base liquid, a phase separation agent, and an activator.

[0031] The base liquid is composed of hydroxyethylethylenediamine, diethylaminoethanol and water. The base liquid is the basic absorption liquid, which is used to ensure the loading capacity and high absorption rate of the CO2 phase change absorption system. Alcoholamine molecules such as hydroxyethylethylenediamine and diethylaminoethanol, as alkaline substances, can promote the reaction of CO2 and water to generate bicarbonate ions. This promotion effect helps to increase the absorption rate of CO2.

[0032] The additives include a volatility suppressant, an antioxidant and oxide nanoparticles, wherein the volatility suppressant is glycine, and the antioxidant contains at least potassium sodium tartrate or antimony potassium tartrate.

[0033] The present invention introduces glycine into the entire phase change absorption system as a volatility suppressant to reduce the volatilization of the absorbent, thereby reducing the absorption cost and protecting the environment. The selected glycine is a salt compound, which increases the boiling point of the solution when it is dissolved in a solvent. This is because the presence of glycine molecules interferes with the interaction between water molecules, making the evaporation of water molecules require more energy. Therefore, the boiling point of the solution increases and the volatility decreases. According to Raoult's law, the presence of solutes reduces the vapor pressure of the solution. Glycine molecules occupy some spaces that originally belonged to solvent molecules, reducing the number of solvent molecules on the surface of the solution, thereby reducing the vapor pressure and reducing volatilization.

[0034] Potassium sodium tartrate or potassium antimony tartrate is a weak acid salt. When dissolved in water, it can partially dissociate to produce tartrate ions, which then form complexes with amine substances (including hydroxyethylethylenediamine and diethylaminoethanol) and form hydrogen bonds with water to avoid oxidative degradation of amine substances.

[0035] After the oxide nanoparticles are introduced into the whole system, the present invention can promote the desorption of CO2, and based on the activation energy effect, thermal conductivity enhancement and surface effect, the mass transfer and heat transfer mechanism in the desorption process are affected. First, since the liquid molecules adhere to the nanoparticles with high kinetic energy, the collision between the liquid molecules and the particles increases, so that when the nanoparticles are present, the average activation energy of the particles in the solution increases, thereby promoting the desorption of CO2. Secondly, the nanoparticles can improve the thermal conductivity of the solution. The addition of nanoparticles changes the average thermal conductivity and heat distribution of the initial solution, affecting the heat transfer enhancement mechanism. Further, due to the addition of nanoparticles with high thermal conductivity, the temperature of the solution can be increased faster than that without addition. Therefore, due to the rapid dispersion of energy and the rapid increase in temperature, the presence of nanoparticles makes the CO2 desorption rate in the solution faster. For the surface effect, the surface effect will cause the characteristics of the boiling liquid surface to change, such as the density of nucleation sites, the heat transfer area and the roughness. Due to the high temperature in the desorption tower 6 (regeneration section), the deposition of nanoparticles on the inner surface of the tower is intensified, forming a porous layer with higher wettability and roughness. The present invention can form nanoparticle clusters by adding a larger amount of oxide nanoparticles. If the size of the nanoparticle clusters is larger than the initial roughness of the inner surface of the tower, the density of nucleation sites on the surface will increase due to the generation of more cavities, scratches and pits, thereby generating more bubbles and higher fluid turbulence, further improving the ability of CO2 desorption.

[0036] In some embodiments of the present invention, the oxide nanoparticles are any one of CuO, Fe3O4, ZnO, SiO2 or Al2O3. For example, when Fe3O4 is used as the oxide nanoparticles, the desorption capacity is improved best.

[0037] In some embodiments of the present invention, the antioxidant further includes any one or more of ethylenediaminetetraacetic acid or sodium sulfite. Whether ethylenediaminetetraacetic acid and sodium sulfite are added can be adjusted according to actual conditions to reduce the thermal degradation and oxidative degradation of the effective components of the CO2 phase change absorption system and ensure the stability of the CO2 phase change absorption system.

[0038] In some embodiments of the present invention, a phase separation agent is used to achieve stratification after the absorption system regenerates CO2, realizes autonomous self-extraction of the organic phase, ensures the stratification ratio, and thus reduces energy consumption. The phase separation agent is n-butanol to achieve physical stratification.

[0039] In some embodiments of the present invention, the activator is 2-amino-2-methyl-1-propanol. The activator is used to increase the reaction rate of the absorption system to absorb CO2 and the reaction rate of desorbing CO2. 2-amino-2-methyl-1-propanol, hydroxyethylethylenediamine and diethylaminoethanol are all alcohol amine molecules. As alkaline substances, they can promote the reaction of CO2 and water to generate bicarbonate ions, which helps to increase the absorption rate of CO2.

[0040] In some embodiments of the present invention, in the CO2 phase change absorption system, based on the mass of the main agent as 100%, the amount of the volatility inhibitor added in the additive is 0.2% to 0.85% of the mass of the main agent, the amount of the antioxidant added is 0.15% to 0.5% of the mass of the main agent, and the amount of the oxide nanoparticles added is 1% to 3% of the mass of the main agent.

[0041] The overall mass fraction of the main agent is 100%, of which the mass fraction of the base liquid is 82%~85%, the mass fraction of the phase separation agent is 12%~15%, and the mass fraction of the activator is 1%~3%.

[0042] In some embodiments of the present invention, the base liquid is composed of hydroxyethylethylenediamine, diethylaminoethanol and water, wherein a mixture of hydroxyethylethylenediamine and diethylaminoethanol is used as a basic absorbent with a mass fraction of 54% to 58%, and the remainder is water.

[0043] Furthermore, in the mixture of hydroxyethylethylenediamine and diethylaminoethanol, the mass fraction of hydroxyethylethylenediamine is 28% to 29%, and the remainder is diethylaminoethanol.

[0044] As a preferred scheme, in the CO2 phase change absorption system, the mass fraction of the base liquid is 83%, the mass fraction of the phase separation agent is 15%, the mass fraction of the activator is 2%, the mass fraction of the volatility suppressant is 0.2% to 0.85% of the mass of the main agent, and the mass fraction of the antioxidant is 0.15% to 0.5% of the mass of the main agent.

[0045] More preferably, the base liquid contains 28% hydroxyethylethylenediamine, 30% diethylaminoethanol and 25% water.

[0046] The second aspect of the present invention discloses a method for preparing a CO2 phase change absorption system, the process of the preparation method is: the base liquid, phase separation agent, volatility inhibitor, activator, antioxidant and oxide nanoparticles are mixed uniformly according to a set mass ratio to obtain the CO2 phase change absorption system.

[0047] The third aspect of the present invention discloses an application of a CO2 phase change absorption system, which is particularly suitable for adsorbing low partial pressure CO2 in coal-fired boiler flue gas. Specifically, it can adsorb CO2 partial pressure of 10 KPa to 15 KPa in coal-fired boiler flue gas.

[0048] The present invention is further described below in conjunction with the examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. It should be noted that the following examples are all at 1000Nm 3 / d CO2 capture continuous test was completed on an experimental device.

[0049] Experimental setup Figure 1 As shown, it includes an absorption tower 1, a delivery pump 2, a two-phase separator 3, a heater 4, a heat exchanger 5, a desorption tower 6, a flash evaporator 7, a compressor 8 and a cooler 9.

[0050] The liquid outlet of the absorption tower 1 is connected to the delivery pump 2, the outlet of the delivery pump 2 is connected to the liquid inlet of the two-phase separator 3, the lean liquid outlet of the two-phase separator 3 is connected to the inlet of the cooler 9, the rich liquid outlet of the two-phase separator 3 is connected to the inlet of the heater 4, the outlet of the heater 4 is connected to the cold side inlet of the heat exchanger 5, and the cold side outlet of the heat exchanger 5 is connected to the rich liquid inlet of the desorption tower 6.

[0051] The regeneration lean liquid outlet of the desorption tower 6 is connected to the hot side inlet of the heat exchanger 5 , the hot side outlet of the heat exchanger 5 is connected to the inlet of the cooler 9 , and the outlet of the cooler 9 is connected to the lean liquid inlet of the absorption tower 1 .

[0052] The lean liquid steam outlet of the desorption tower 6 is connected to the inlet of the flash evaporator 7, the outlet of the flash evaporator 7 is connected to the inlet of the compressor 8, and the outlet of the compressor 8 is connected to the steam inlet of the desorption tower 6; further, in order to ensure that the lean liquid steam temperature at the outlet of the compressor 8 meets the requirements, a heating device is provided between the outlet of the compressor 8 and the steam inlet of the desorption tower 6.

[0053] The process of absorbing CO2 through the above system is as follows: the flue gas enters the absorption tower 1 from bottom to top, and the lean liquid in the absorption tower 1 absorbs the flue gas CO2 from top to bottom, and the two are in countercurrent contact to carry out a decarbonization reaction; the liquid after absorbing the CO2 in the flue gas reaches the two-phase separator 3 through the delivery pump 2, and the liquid is divided into lean liquid and rich liquid in the two-phase separator 3, and the lean liquid absorbent discharged from the two-phase separator 3 is sprayed from top to bottom into the absorption tower 1, and the temperature of the lean liquid absorbent discharged from the two-phase separator 3 and entering the absorption tower 1 is controlled at 35°C~45°C.

[0054] The process of desorbing CO2 by the above system is as follows: the liquid that absorbs CO2 is discharged from the bottom of the two-phase separator 3, and after being heated by the heater 4 and the heat exchanger 5, the temperature is controlled at 95°C~105°C, and after being heated, it enters the desorption tower 6 for desorption; the regenerated gas desorbed from the rich liquid enters the flash evaporator 7 from the lean liquid steam outlet at the bottom of the desorption tower 6 and is heated to become steam, and then compressed by the compressor 8 to form high-temperature lean liquid steam. The high-temperature lean liquid steam reacts with the rich liquid entering the desorption tower 6 to generate gaseous CO2 and regenerated lean liquid. The regenerated lean liquid flows out from the regeneration lean liquid outlet at the bottom of the desorption tower 6, passes through the cooler 9 and re-enters the absorption tower 1 to start a new absorption process.

[0055] Preferably, the high-temperature lean liquid steam output from the compressor 8 has a temperature range of 100° C. to 150° C. and a pressure range of 30 KPa to 100 KPa.

[0056] In the above process, the lean liquid and rich liquid in the entire system circulation process are the CO2 phase change absorption system of the present invention, which are divided into lean liquid and rich liquid according to the different CO2 contents.

[0057] Test process: A mixed gas containing CO2, O2 and N2 (simulating flue gas components) at a temperature of 40°C and a gas phase CO2 partial pressure of 0.1 MPa was input into a 1000Nm 3 / d CO2 capture continuous test experimental device. The diameter of absorption tower 1 is 150dm, the height is 15m, and the packing layer height is 10m; the diameter of desorption tower is 150dm, the height is 12m, and the packing layer height is 8m; the solution circulation volume is 500L / h, and the air intake volume is 42Nm 3 / h, the absorption temperature of the CO2 phase change absorption system for capturing CO2 in the exhaust gas is 40°C, and the desorption temperature is controlled by the heater at the bottom of the desorption tower 6. Sampling ports are provided at the bottom of the absorption tower 1 and the desorption tower 6. After the experiment started, sampling and analysis were conducted every day, and sampling and analysis were conducted at the bottom of the absorption tower 1 and the desorption tower 6 to determine the CO2 content in the solution. After one week of continuous operation, sampling was conducted at the bottom of the desorption tower, and the solution components were analyzed by GC-MS gas chromatography-mass spectrometry to determine the degradation rate. The device was shut down after one week of continuous operation.

[0058] The following is a further description with reference to specific comparative examples and embodiments.

[0059] Comparative Example 1 The composition of the water-poor CO2 phase change absorption system is hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol and 2-amino-2-methyl-1-propanol, and the corresponding mass fractions are 28%, 30%, 25%, 15% and 2%, respectively.

[0060] Relevant test data are shown in Table 1.

[0061] Table 1 Comparative Example Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas

[0062] Example 1 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol and glycine, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2% and 0.2%.

[0063] The relevant test data are shown in Table 2.

[0064] Table 2 Absorption and desorption test results of the CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 1

[0065] Example 2 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol and glycine, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2% and 0.4%.

[0066] The relevant test data are shown in Table 3.

[0067] Table 3 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 2

[0068] Example 3 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol and glycine, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2% and 0.65%.

[0069] Relevant test data are shown in Table 4.

[0070] Table 4 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 3

[0071] Example 4 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol and glycine, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2% and 0.85%.

[0072] The relevant test data are shown in Table 5.

[0073] Table 5 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 4

[0074] It can be seen from the above-mentioned Examples 1 to 4 that, with the gradual addition of glycine, the degradation amount of the system shows a trend of first decreasing and then remaining constant, and finally the degradation amount stabilizes at 1.7 kg / t of CO2.

[0075] Example 5 The composition of the water-reduced CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and potassium sodium tartrate, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 0.15%.

[0076] The relevant test data are shown in Table 6.

[0077] Table 6 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 5

[0078] Example 6 The composition of the water-reduced CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and potassium sodium tartrate, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 0.5%.

[0079] Relevant test data are shown in Table 7.

[0080] Table 7 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 6

[0081] Example 7 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and potassium antimony tartrate, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 0.15%, respectively.

[0082] Relevant test data are shown in Table 8.

[0083] Table 8 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 7

[0084] Example 8 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and potassium antimony tartrate, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 0.5%.

[0085] Relevant test data are shown in Table 9.

[0086] Table 9 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 8

[0087] Example 9 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and composite antioxidant (the mass ratio of ethylenediaminetetraacetic acid, potassium antimony tartrate and sodium sulfite is 1:1:1), and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 0.15%, respectively.

[0088] Relevant test data are shown in Table 10.

[0089] Table 10 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 9

[0090] Example 10 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and composite antioxidant (ethylenediaminetetraacetic acid, potassium antimony tartrate, sodium sulfite = 1:1:1), and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4%, and 0.5%.

[0091] Relevant test data are shown in Table 11.

[0092] Table 11 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 10

[0093] It can be seen from Examples 5 to 10 that with the addition of volatility suppressants and antioxidants, the desorption amount of the system shows a trend of first increasing and then decreasing, and can form a highest desorption point of 50LCO2 / L solution. Due to the influence of increased viscosity after absorption, the desorption amount shows a decreasing trend.

[0094] Embodiment 11 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and CuO, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4% and 2%.

[0095] Relevant test data are shown in Table 12.

[0096] Table 12 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 11

[0097] Example 12 The composition of the water-poor CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and Fe3O4, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.85% and 1%.

[0098] Relevant test data are shown in Table 13.

[0099] Table 13 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 12

[0100] Embodiment 13 The composition of the water-reduced CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine and Fe3O4, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.85% and 3%.

[0101] Relevant test data are shown in Table 14.

[0102] Table 14 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 13

[0103] Embodiment 14 The composition of the water-less CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium antimony tartrate and ZnO, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4%, 0.15% and 2%.

[0104] Relevant test data are shown in Table 15.

[0105] Table 15 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 14

[0106] Embodiment 15 The composition of the water-less CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium antimony tartrate and ZnO, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4%, 0.15% and 1%.

[0107] Relevant test data are shown in Table 16.

[0108] Table 16 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 15

[0109] Example 16 The composition of the water-reduced CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium sodium tartrate and SiO2, and the corresponding mass fractions are: 28%, 30%, 25%, 15%, 2%, 0.4%, 0.4% and 2%.

[0110] Relevant test data are shown in Table 17.

[0111] Table 17 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 16

[0112] Embodiment 17 The composition of the water-reduced CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium sodium tartrate and SiO2, and the corresponding mass fractions are: 28%, 29%, 25%, 15%, 3%, 0.4%, 0.5% and 3%.

[0113] Relevant test data are shown in Table 18.

[0114] Table 18 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 17

[0115] Embodiment 18 The composition of the water-less CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium sodium tartrate and Al2O3, and the corresponding mass fractions are: 29%, 31%, 25%, 14%, 1%, 0.4%, 0.5% and 1%.

[0116] Relevant test data are shown in Table 19.

[0117] Table 19 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 18

[0118] Embodiment 19 The composition of the water-less CO2 phase change absorption system suitable for low partial pressure CO2 capture and purification is: hydroxyethylethylenediamine, diethylaminoethanol, water, n-butanol, 2-amino-2-methyl-1-propanol, glycine, potassium sodium tartrate and Al2O3, and the corresponding mass fractions are: 29%, 31%, 25%, 12%, 3%, 0.4%, 0.5% and 3%.

[0119] Relevant test data are shown in Table 20.

[0120] Table 20 Absorption and desorption test results of CO2 phase change absorption system for capturing CO2 in exhaust gas in Example 19

[0121] By comparing the above embodiments, it can be found that the CO2 content in the CO2 phase change absorption system with the addition of oxide nanoparticles after desorption can be reduced by 20% to 30% compared with the CO2 phase change absorption system without the addition of oxide nanoparticles, indicating that oxide nanoparticles are helpful for the desorption process.

[0122] The present invention is suitable for a low-water phase change absorption system for capturing and purifying low-fraction CO2. The low-water phase change absorption system in the regeneration process can reduce the regeneration energy consumption and the regeneration temperature, and improve the regeneration rate. It has the advantages of large CO2 absorption capacity, high CO2 capture rate, slow equipment corrosion rate, good self-stability, low regeneration temperature, low regeneration energy consumption, and good degradation effect.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A CO2 phase change absorption system, characterized in that: It comprises a main agent and additives; the main agent comprises a base liquid, a phase separation agent and an activator; the additives comprise a volatility suppressant, an antioxidant and oxide nanoparticles; The base liquid consists of hydroxyethylethylenediamine, diethylaminoethanol and water; The volatility suppressant is glycine; The antioxidant contains at least sodium potassium tartrate or potassium antimony tartrate; The mass of oxide nanoparticles is 1% to 3% of the mass of the main agent; The sum of the mass fractions of hydroxyethylethylenediamine and diethylaminoethanol in the base liquid is 54% to 58%, and the balance is water; In terms of mass fraction, the oxide nanoparticles are any one of CuO, Fe3O4, ZnO, SiO2 or Al2O3; The oxide nanoparticles are used in the desorption tower (6) to promote CO2 desorption.

2. A CO2 phase change absorption system according to claim 1, characterized in that: The antioxidant further contains any one or both of ethylenediaminetetraacetic acid and sodium sulfite.

3. A CO2 phase change absorption system according to claim 1, characterized in that: The phase separation agent is n-butanol.

4. A CO2 phase change absorption system according to claim 1, characterized in that: The activating agent is 2-amino-2-methyl-1-propanol.

5. A CO2 phase change absorption system according to claim 1, characterized in that: The mass of the volatility suppressant is 0.2% to 0.85% of the mass of the main agent, and the mass of the antioxidant is 0.15% to 0.5% of the mass of the main agent.

6. A CO2 phase change absorption system according to claim 1, characterized in that: In the main agent, the mass fraction of the base liquid is 82% to 85%, the mass fraction of the phase separation agent is 12% to 15%, and the mass fraction of the activator is 1% to 3%.

7. A method for preparing the CO2 phase change absorption system according to claim 1, characterized in that: The CO2 phase change absorption system is obtained by mixing hydroxyethylethylenediamine, diethylaminoethanol, water, a phase separation agent, a volatility suppressant, an activator, an antioxidant and oxide nanoparticles according to a set mass ratio.

8. An application of the CO2 phase change absorption system according to claim 1, characterized in that: Used to absorb CO2 in flue gas from coal-fired boilers.

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