Solid amine adsorbent pressure swing desorption method, device and application

Abstract

The present invention belongs to the technical field of solid amine adsorption and desorption, and specifically relates to a solid amine adsorbent pressure swing desorption method, device and application. The desorption method comprises the following steps: in a coupled external field, desorbing the solid amine adsorbent at a desorption temperature; wherein the solid amine adsorbent adsorbs carbon dioxide, and the desorption temperature differs from the adsorption temperature of the solid amine adsorbent by 0°C to 5°C. By applying a coupled external field to the solid amine adsorbent adsorbing carbon dioxide, the temperature of the solid amine adsorbent during the desorption stage is maintained at about the temperature during the adsorption stage, and while preventing the solid amine adsorbent from chemical degradation, that is, maintaining its activity, carbon dioxide can be completely desorbed from it at low temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of solid amine adsorption and desorption, and in particular relates to a solid amine adsorbent pressure swing desorption method, device and application. Background Art

[0002] Solid amine adsorbents have strong separation performance and high adsorption capacity. 2 It has been widely used in the capture field. Solid amine adsorbent is a chemical adsorption. The adsorption heat is very large during adsorption, which causes the temperature of the adsorption bed to rise; while during desorption, heat is absorbed, causing the temperature of the adsorption bed to decrease. The reduced temperature in turn affects the desorption rate of the solid amine adsorbent. Therefore, when the solid amine adsorbent is desorbed, it is often heated to a high temperature to increase its desorption rate. However, at high temperatures of adsorption exothermicity or in an environment of high-temperature heating for desorption, the solid amine adsorbent will chemically degrade, resulting in a shortened life and reduced adsorption performance. Therefore, solid amine is used to capture CO 2 The temperature needs to be strictly controlled during both the adsorption and desorption stages.

[0003] For existing solid amine adsorption of CO 2 Processes, one of which is to make the adsorbent only partially desorb at a lower desorption temperature, that is, to sacrifice part of the adsorption capacity of the adsorbent to extend its cycle life; however, this process indirectly reduces the adsorption capacity of the solid amine adsorbent, losing its use advantage. Another process is to increase the desorption temperature to make the solid amine adsorbent completely desorb, but since the solid amine adsorbent will decompose and become inactivated at high temperatures, the adsorbent needs to be replaced frequently, which in turn increases industrial costs.

[0004] In summary, solid amine adsorbents are accompanied by a large temperature difference problem between the adsorption stage and the desorption stage, which is the difficulty that makes it difficult to reasonably and effectively utilize solid amine adsorbents. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a solid amine adsorbent pressure swing desorption method, device and application. The desorption method is to apply a coupled external field to the solid amine adsorbent adsorbing carbon dioxide, so that the temperature of the solid amine adsorbent in the desorption stage is maintained at about the temperature during the adsorption stage, and the solid amine adsorbent is prevented from chemical degradation, that is, the activity is maintained, and carbon dioxide can be completely desorbed from it at low temperature.

[0006] The present invention is achieved through the following technical solutions:

[0007] One of the purposes of the present invention is to provide a solid amine adsorbent pressure swing desorption method, comprising the following steps:

[0008] In a coupled external field, the solid amine adsorbent is desorbed at a desorption temperature;

[0009] The solid amine adsorbent adsorbs carbon dioxide, and the desorption temperature differs from the adsorption temperature of the solid amine adsorbent by 0°C to 5°C.

[0010] The solid amine adsorbent pressure swing desorption method provided by the present invention is to apply a coupled external field to the solid amine adsorbent that has adsorbed carbon dioxide in the desorption stage of the adsorbent under the conditions of a pressure swing adsorption process, so that the temperature of the solid amine adsorbent in the desorption stage varies around the adsorption temperature, and the carbon dioxide can be completely desorbed therefrom in a low temperature environment while maintaining the activity of the solid amine adsorbent.

[0011] In some possible implementations, the adsorption temperature is 50°C to 105°C; preferably 50°C to 80°C.

[0012] In some possible implementations, the coupled external field includes at least one of microwaves, magnetic fields, and electric fields.

[0013] In some possible implementations, the frequency of the microwave is 0 MHz to 1500 MHz, preferably 915 MHz.

[0014] In some possible implementations, the power of the microwave is 0 kW to 3.0 kW, preferably 1.8 kW.

[0015] In some possible implementations, the duty cycle of the microwaves is 0% to 50%, preferably 20%.

[0016] In some possible implementations, the intensity of the magnetic field is 0 mT to 1000 mT, preferably 800 mT.

[0017] In some possible implementations, the intensity of the electric field is 0 kV / m to 100 kV / m, preferably 60 kV / m.

[0018] In some possible implementations, the relative humidity of the environment in which the solid amine adsorbent is desorbed is 0% to 50%.

[0019] In some possible implementations, the solid amine adsorbent is desorbed under vacuum, and the vacuum degree is 10 kPa to 95 kPa.

[0020] A second object of the present invention is to provide a device suitable for the solid amine adsorbent pressure swing desorption method provided in this application.

[0021] The device provided in the embodiment of the present invention is applied to the solid amine adsorbent pressure swing desorption method provided in the present application, on the premise that it is suitable for the adsorbent pressure swing adsorption and desorption process.

[0022] In some possible implementations, the solid amine adsorbent structure in the device is a fixed bed or a rotating wheel.

[0023] A third object of the present invention is to provide an application of the solid amine adsorbent pressure swing desorption method provided by the present invention in the field of carbon capture technology. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application clearer, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application without the description of these details.

[0026] The following examples serve to illustrate the present application. In the examples, unless otherwise indicated, parts are by weight, percentages are by weight, and temperatures are in degrees Celsius. The relationship between parts by weight and parts by volume is the same as the relationship between grams and cubic centimeters.

[0027] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0028] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0029] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0030] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0031] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0032] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0033] At present, solid amine adsorbents are mainly used in temperature swing adsorption process and pressure swing adsorption process.

[0034] The following technical problems exist in the application of temperature swing adsorption (TSA) process: (1) Thermal stability problem: The TSA process requires a large amount of heat to be provided during the adsorption and desorption stages of the adsorbent. In particular, during the desorption stage, the adsorbent surface needs to be quickly heated to a high temperature to promote the target gas (such as CO 2 ) desorption, while solid amine adsorbents will degrade and become inactivated under high temperature conditions. Frequent temperature cycles (heating for desorption and cooling for adsorption) will accelerate the degradation and inactivation of the adsorbent and shorten the service life of the adsorbent; (2) Difficulty in heat management: The TSA process requires the removal of a large amount of heat in the adsorption stage, and a large amount of heat needs to be provided in the desorption stage. Solid amine adsorbents have a large heat capacity, and there are energy losses or heat uniformity problems during the heat transfer process. In the adsorption bed, if the adsorbent is heated unevenly, it is easy to cause local overheating or cooling, affecting the life of the adsorbent. In other words, solid amine adsorbents have problems with thermal stability and heat management difficulties in the temperature swing adsorption process.

[0035] In the pressure swing adsorption process, providing medium temperature and high pressure conditions during the adsorption process of solid amine adsorbent can enable solid amine to successfully adsorb CO 2 , adsorption process of solid amine and CO2 The adsorption heat is very large, which will greatly increase the temperature of the entire adsorbent. However, since desorption requires the adsorption of a large amount of heat, the adsorption heat during adsorption alone cannot provide the energy required for the desorption of the solid amine adsorbent. Therefore, the temperature of the adsorbent drops rapidly during desorption. Even if the adsorbent is heated to provide heat, it cannot provide sufficient desorption energy in a process such as pressure swing adsorption that needs to be switched in a short time.

[0036] In order to maintain the desorption and regeneration performance of the solid amine adsorbent, an embodiment of the present invention proposes a pressure swing desorption method for a solid amine adsorbent. The method is based on a pressure swing adsorption process. In the desorption stage, a coupled external field is applied to the solid amine adsorbent to keep the desorption temperature of the solid amine adsorbent at the temperature during the adsorption stage. While maintaining the activity of the solid amine adsorbent, carbon dioxide can be completely desorbed therefrom in a low temperature environment.

[0037] For the convenience of description, the following embodiments of the present invention are described by taking the solid amine adsorbent pressure swing desorption method, device and application as an example.

[0038] A first aspect of an embodiment of the present invention provides a solid amine adsorbent pressure swing desorption method, comprising the following steps:

[0039] In a coupled external field, the solid amine adsorbent is desorbed at a desorption temperature;

[0040] The solid amine adsorbent adsorbs carbon dioxide, and the desorption temperature differs from the adsorption temperature of the solid amine adsorbent by 0°C to 5°C.

[0041] The solid amine adsorbent pressure swing desorption method provided in an embodiment of the present invention is to apply a coupled external field to the solid amine adsorbent that has adsorbed carbon dioxide in the adsorbent desorption stage under a pressure swing adsorption process, so that the desorption temperature of the solid amine adsorbent is maintained at the temperature during the adsorption stage. While maintaining the activity of the solid amine adsorbent, carbon dioxide can be completely desorbed therefrom in a low temperature environment.

[0042] In the embodiment, the difference between the desorption temperature and the adsorption temperature of the solid amine adsorbent can be 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, etc., which are typical but non-limiting temperature differences, or a range between any two temperature differences.

[0043] In some embodiments, the coupled external field includes at least one of microwaves, magnetic fields, and electric fields. In this case, ① for microwaves: microwaves can accelerate the polarization and depolarization processes of the molecules of the substance, and can increase the reaction rate even under low temperature conditions. This non-thermal effect is different from the simple thermal energy effect and may change the reaction mechanism and rate. Microwave radiation can increase the energy on the surface of the solid amine material, increase the active sites, and thus promote the desorption reaction. The molecular motion and polarization effect caused by microwaves can promote molecular diffusion, increase the mass transfer rate between reactants and products, and further accelerate the desorption process. ② For magnetic field: the magnetic field will change the magnetization state of solid amine materials, affect the physical and chemical environment inside them, thereby changing the energy state distribution on the adsorbent surface, reducing the adsorption energy of gas molecules and promoting the desorption process. Secondly, the magnetic field can increase the kinetic energy and momentum of gas molecules, which helps to overcome the adsorption energy barrier and make it easier for gas molecules to desorb from the adsorbent surface. ③ For electric field: under the action of the electric field, the adsorbent and adsorbed molecules will be polarized. Polarization changes the electric potential energy of the adsorbed molecules and weakens their interaction with the adsorbent surface, thereby reducing the desorption energy barrier and making it easier for the adsorbed molecules to desorb. The electric field applied to the adsorbent can increase the energy inside the adsorbed molecules and the adsorbent, making the molecular movement more active. This enhanced molecular movement helps to overcome the adsorption potential energy and make it easier for the molecules to detach from the adsorbent surface. The local electric field effect generated by the electric field on the adsorbent surface will change the charge distribution on the surface. This change can weaken the electrostatic interaction force between the adsorbed molecules and the adsorbent surface, thereby promoting the desorption of molecules. The electric field can change the state of the surface active sites, making it more unfavorable for the stable binding of the adsorbed molecules, thereby promoting desorption. For CO 2 For such polar gas molecules, the applied electric field can be a directional force (electrokinetic effect), pushing these molecules away from the adsorbent surface, thereby accelerating the desorption process.

[0044] In some embodiments, the frequency of the microwaves is 0 MHz to 1500 MHz. In exemplary embodiments, the frequency may be 0 MHz, 100 MHz, 300 MHz, 500 MHz, 690 MHz, 780 MHz, 915 MHz, 1220 MHz, 1500 MHz, or other typical but non-limiting frequencies or a range between any two frequencies.

[0045] In other embodiments, the frequency of the microwave is 500 MHz to 1500 MHz, and in the exemplary examples, it can be 500 MHz, 690 MHz, 780 MHz, 915 MHz, 1220 MHz, 1500 MHz, or any range between two frequencies. In this case, the solid amine material has the best absorption effect on microwaves, effectively stimulating energy transfer and chemical bonds between molecules of the solid amine adsorbent, promoting the reaction rate, and thus accelerating the desorption process of the solid amine adsorbent.

[0046] In some embodiments, the power of the microwave is 0 kW to 3.0 kW. In exemplary embodiments, the power may be 0 kW, 0.6 kW, 1.2 kW, 2.0 kW, 2.8 kW, 3.0 kW, or other typical but non-limiting powers or a range between any two powers.

[0047] In other embodiments, the power of the microwave is 0.6 kW to 3.0 kW, and in the exemplary embodiment, it can be 0.6 kW, 1.2 kW, 2.0 kW, 2.8 kW, 3.0 kW, etc., which are typical but non-limiting powers, or a range between any two powers. In this case, the power range can improve the desorption efficiency, allowing more carbon dioxide to be desorbed in a shorter time.

[0048] In some embodiments, the duty cycle of the microwaves is 0% to 50%. In exemplary embodiments, the duty cycle may be 0%, 10%, 20%, 30%, 40%, 50%, or other typical but non-limiting duty cycles or a range between any two duty cycles.

[0049] In other embodiments, the duty cycle of the microwave is 10% to 50%. In the exemplary embodiment, the duty cycle may be 10%, 20%, 30%, 40%, 50%, etc., which are typical but non-limiting duty cycles, or a range between any two duty cycles. In this case, the microwave can effectively supply sufficient energy for the desorption of the solid amine.

[0050] Duty cycle refers to the ratio of the microwave on time in a cycle to the total cycle time. Assuming an industrial microwave heating process, the total microwave cycle time is 10 seconds, and the duty cycle is 50%: the microwave is on for 5 seconds and off for 5 seconds.

[0051] In some embodiments, the strength of the magnetic field is 0 mT to 1000 mT. In exemplary embodiments, it can be 0 mT, 200 mT, 400 mT, 500 mT, 600 mT, 700 mT, 800 mT, 900 mT, 1000 mT or other typical but non-limiting strengths or a range between any two strengths.

[0052] In other embodiments, the strength of the magnetic field is 500mT to 1000mT. In the exemplary embodiment, it can be 500mT, 600mT, 700mT, 800mT, 900mT, 1000mT, etc., which are typical but non-limiting strengths, or a range between any two strengths. In this case, the magnetic field can change the magnetization state of the solid amine adsorbent, affect the physical and chemical environment inside it, thereby changing the energy state distribution on the adsorbent surface, reducing the adsorption energy of gas molecules, and promoting the desorption process; and the magnetic field can increase the kinetic energy and momentum of the gas molecules, which helps the solid amine adsorbent overcome the adsorption energy barrier and makes it easier for the gas molecules to desorb from the adsorbent surface.

[0053] In some embodiments, the intensity of the electric field is 0 kV / m to 100 kV / m. In exemplary embodiments, it can be 0 kV / m, 10 kV / m, 20 kV / m, 30 kV / m, 40 kV / m, 50 kV / m, 60 kV / m, 70 kV / m, 80 kV / m, 90 kV / m, 100 kV / m, or other typical but non-limiting intensities, or a range between any two intensities.

[0054] In other embodiments, the intensity of the electric field is 10 kV / m to 100 kV / m. In exemplary embodiments, the electric field may be 10 kV / m, 20 kV / m, 30 kV / m, 40 kV / m, 50 kV / m, 60 kV / m, 70 kV / m, 80 kV / m, 90 kV / m, 100 kV / m, or other typical but non-limiting intensities or a range between any two intensities. In this case, the carbon dioxide in the adsorbent is polarized, which changes the electric potential energy of the carbon dioxide and weakens the interaction force between the carbon dioxide and the adsorbent, thereby reducing the desorption energy barrier and making it easier for the carbon dioxide to desorb. Moreover, the electric field can increase the energy inside the carbon dioxide and the adsorbent, making the movement of carbon dioxide molecules more active, thereby overcoming the adsorption potential and making it easier to detach from the adsorbent surface; furthermore, the local electric field effect generated by the electric field on the adsorbent surface changes the charge distribution on the adsorbent surface, thereby weakening the electrostatic interaction between carbon dioxide and the adsorbent and promoting the desorption of carbon dioxide; the electric field can also change the state of the active sites on the adsorbent surface, reducing the stability of its binding with carbon dioxide, thereby promoting the desorption of carbon dioxide. Finally, for CO 2 This polar gas molecule can exert a directional force (electrokinetic effect) to push these CO 2 The molecules leave the adsorbent surface, accelerating the desorption process.

[0055] In some embodiments, the adsorption temperature is 50°C to 105°C. In exemplary embodiments, it can be a typical but non-limiting temperature such as 50°C, 70°C, 90°C, 100°C, 105°C, or a range between any two temperatures. In this case, since the desorption temperature is only 0°C to 5°C different from the adsorption temperature, a lower desorption temperature can prevent the solid amine adsorbent from chemical degradation and maintain activity, while completely desorbing carbon dioxide from the adsorbent at low temperatures.

[0056] In some embodiments, the solid amine adsorbent is desorbed under vacuum, and the vacuum degree is 10kPa to 95kPa. In the exemplary embodiment, it can be a typical but non-limiting vacuum degree such as 10kPa, 20kPa, 40kPa, 60kPa, 80kPa, 90kPa, 95kPa, or a range between any two vacuum degrees. Under vacuum conditions, the gas partial pressure in the desorption system is significantly reduced. This low-pressure environment reduces the possibility of gas re-adsorption onto the solid amine, thereby promoting easier desorption of the already adsorbed gas; in a vacuum environment, the mean free path of gas molecules becomes longer and the diffusion rate increases, which makes it easier for the adsorbed gas molecules to escape from the adsorbent surface and improve the desorption efficiency; under vacuum conditions, the physical and chemical potential energy of the gas is reduced, and the interaction between carbon dioxide and the adsorbent surface is weakened, making it easier for carbon dioxide to overcome the adsorption energy barrier and desorb. In addition, under vacuum conditions, carbon dioxide gas is quickly removed, avoiding gas accumulation and promoting carbon dioxide desorption.

[0057] In some embodiments, the material of the organic amine in the solid amine adsorbent includes: monoethanolamine, diethanolamine, polyethyleneimine (PEI), amide, tetraethylenepentamine, diethylenetriamine, or more. The adsorption temperature of these solid amines is between 50 and 105°C. At this adsorption temperature, the active sites of the solid amine adsorbent will be fully activated, thereby increasing the adsorption capacity. The adsorbent with a suitable adsorption temperature can also reduce the competitive adsorption of other gases or chemicals on the target molecules, thereby increasing the adsorption of the adsorbent on CO. 2 adsorption selectivity.

[0058] In some specific embodiments, a solid amine adsorbent pressure swing adsorption desorption method is provided, comprising the following steps:

[0059] S1. The high-temperature flue gas is cooled after dust removal, denitrification and desulfurization, and the waste heat of the high-temperature flue gas is collected during the cooling process.

[0060] S2. Remove moisture from the cooled flue gas and obtain dry flue gas at the tail.

[0061] S3. At a temperature of 80°C and a pressure of 0.5 MPa, a solid amine adsorbent is used to adsorb carbon dioxide in the dry flue gas.

[0062] S4. Under a vacuum degree of 90 kPa, a microwave frequency of 500 MHz to 1500 MHz, a microwave power of 0.6 KW to 3.0 KW, a microwave duty cycle of 10% to 50%, a magnetic field strength of 500 mT to 1000 mT, and an electric field strength of 10 kV / m to 100 kV / m is applied. Under the coupling external field, the desorption temperature of the solid amine is 80 ° C. At this temperature, the solid amine adsorbent is desorbed to obtain a high concentration of CO 2 De-inhale.

[0063] In some specific embodiments, a solid amine adsorbent pressure swing adsorption desorption method is provided, comprising the following steps:

[0064] S11. After dust removal, denitrification and desulfurization, the high-temperature flue gas is cooled, and the waste heat of the high-temperature flue gas is collected during the cooling process.

[0065] S21. The moisture in the flue gas after cooling is removed to obtain dry flue gas at the tail.

[0066] S31. At a temperature of 80°C and a pressure of 0.5MPa, a solid amine adsorbent is used to adsorb carbon dioxide in the dry flue gas.

[0067] S41. Under a vacuum degree of 90 kPa, a microwave frequency of 500 MHz to 1500 MHz, a microwave power of 0.6 KW to 3.0 KW, a microwave duty cycle of 10% to 50%, a magnetic field strength of 500 mT to 1000 mT, and an electric field strength of 10 kV / m to 100 kV / m is applied. Under the coupling external field, the desorption temperature of the solid amine is 80 ° C. At this temperature, the solid amine adsorbent is desorbed to obtain a high concentration of CO 2 De-inhale.

[0068] S51. The flue gas waste heat collected in S11 is used as heat for desorption of water and heat for desorption of solid amine adsorbent respectively.

[0069] In some specific embodiments, in the above step S1 or S11, the dust removal step includes: the flue gas from the upstream section first passes through a dust removal device, and the dust removal method can adopt an electrostatic precipitator (ESP) or a bag dust removal (bag filter) process to remove the particulate matter in the flue gas, and the tail gas particulate matter concentration is less than 10mg / Nm 3 , CO 2 The concentration of dust does not change much during the whole dust removal process. Dust removal can prevent excessive dust from entering the subsequent pipelines and equipment, especially CO 2 Adsorption equipment causes pipeline blockage and mechanical wear of equipment and pipelines.

[0070] In some specific embodiments, in the above step S1 or S11, the denitration step includes: the flue gas after dust removal enters the denitration device, and the denitration method includes a selective catalytic reduction method (SCR) to reduce NO in the flue gas. x Remove the tail gas NO x Concentration less than 50mg / Nm 3 , CO 2 The concentration of NO does not change much during the whole denitrification process. Denitrification can avoid the subsequent cooling of NO xIt generates acidic substances with water, which corrode pipes and equipment.

[0071] In some specific embodiments, in the above step S1 or S11, the desulfurization step includes: the flue gas after denitration enters the desulfurization device, and the desulfurization method can adopt a semi-dry process or a wet process to remove SO in the flue gas. 2 Remove the tail gas SO 2 Concentration less than 50mg / Nm 3 , CO 2 The concentration of SO does not change much during the whole desulfurization process. Desulfurization can avoid the subsequent cooling. 2 It can also generate acidic substances with water to corrode pipes and equipment, and can also prevent solid amine adsorbents from reacting with SO 2 The performance of the solid amine adsorbent is reduced due to the reaction of sulfur-containing substances such as sulfur.

[0072] In some specific embodiments, in the above-mentioned step S1 or S11, the high-temperature flue gas is cooled, and the step of collecting the waste heat of the high-temperature flue gas during the cooling includes: the desulfurized flue gas enters the heat exchanger through a blower to cool down, and the temperature drops to 50°C to 105°C, ensuring that the flue gas does not condense in the heat exchanger pipe, and at the same time collecting the waste heat in the flue gas; the heat exchanger is a gas-gas or gas-liquid plate or shell and tube heat exchanger, and the heat exchanger has an anti-corrosion function.

[0073] In some specific embodiments, in the above step S2 or S21, the step of removing moisture from the flue gas after cooling includes: the dehydration process is vacuum pressure swing adsorption, temperature swing adsorption or vacuum temperature swing adsorption process; the dehydration tower is in the form of axial flow or radial flow fixed bed, and the tower is filled with silica gel, zeolite, and alumina as the main mixed adsorbent, and the CO in the flue gas is 2 The concentration remains basically unchanged during the entire dehydration process; after the dehydration tower is saturated with adsorption, it is switched and the flue gas enters another dehydration tower for dehydration; at the same time, the dehydration tower that has been saturated with adsorption is regenerated, and the regeneration method is negative pressure at room temperature, direct heating of the adsorbent by hot air, or negative pressure and indirect heating of the adsorbent at the same time, the negative pressure is -80kPa~-40kPa, and the heating temperature is 120℃~300℃. The water vapor obtained by desorption after adsorption in the dehydration tower is directly discharged. The temperature of the flue gas entering the dehydration tower is 50℃~105℃, and the adsorbent used is a mixed adsorbent of silica gel, zeolite and alumina. The volume ratio of silica gel, zeolite and alumina satisfies (1~20):(1~20):(1~40), and the H of the mixed adsorbent is 100%. 2 The saturated adsorption capacity of O is 4mmol / g~60mmol / g, CO 2The saturated adsorption capacity is <0.1μmol / g. The relative humidity and dew point of the system are monitored in real time using humidity sensors and dew point instruments to ensure that the dew point of the flue gas after drying is -30℃~0℃. The flue gas temperature will not change significantly during the dehydration process, and the temperature of the flue gas after dehydration is still 50℃~105℃.

[0074] In some specific embodiments, in the above step S3 or S31, the adsorption step includes: the flue gas is pressurized to 0.15MPa-1.5MPa (i.e., adsorption pressure) by a blower, while maintaining the flue gas temperature at 50°C-105°C (i.e., adsorption temperature), and CO 2 After being adsorbed into the bed, part of the flue gas after decarbonization is discharged into the atmosphere, and part is used to cool the adsorption device. The constant pressure is ensured to be 0.15MPa~1.5MPa, which can promote CO 2 Mass transfer allows the active sites inside the adsorbent to better interact with CO 2 reaction, ensuring that the internal active sites are fully utilized; the constant temperature of 50℃~105℃ is to give the reaction sufficient activation energy, that is, to activate all the adsorption sites to meet the requirements of CO 2 The reaction conditions, and at this temperature can ensure that the solid amine and CO 2 There will not be too many side reactions to produce products such as urea.

[0075] In some specific embodiments, in the above step S4 or 41, the desorption step includes: using the heat in step S1 or S11 to maintain the desorption temperature at 50°C to 105°C, the microwave frequency at 500MHz to 1500MHz; maintaining the microwave power at 0.6KW to 3.0KW; maintaining the microwave duty cycle at 10% to 50%; the desorption vacuum degree at 10kPa to 95kPa; maintaining the magnetic field strength at 500mT to 1000mT; maintaining the electric field strength at 10kV / m to 100kV / m; during the desorption process, CO 2 It can be desorbed from solid amine adsorbents even at low temperatures.

[0076] The following describes the invention in conjunction with specific embodiments.

[0077] Example 1

[0078] Example 1 provides a solid amine adsorbent pressure swing desorption method, comprising the following steps:

[0079] In three coupling external fields, namely magnetic field, electric field and microwave field, tetraethylenepentamine solid amine adsorbent is desorbed at the desorption temperature.

[0080] During desorption, the vacuum degree was maintained at 90 kPa. In the coupled external field, the microwave frequency was 915 MHz, the power was 1.8 kW, the duty cycle was 20%, the electric field strength was 60 kV / m, and the magnetic field strength was 800 mT. After application, the desorption temperature of the solid amine was 80°C.

[0081] Example 2

[0082] Example 2 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the frequency of the microwave is 500 MHz.

[0083] Example 3

[0084] Example 3 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the frequency of the microwave is 1500 MHz.

[0085] Example 4

[0086] Example 4 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the power of the microwave is 0.6 kW.

[0087] Example 5

[0088] Example 5 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the power of the microwave is 3.0 kW.

[0089] Example 6

[0090] Example 6 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the duty cycle of the microwave is 10%.

[0091] Example 7

[0092] Example 7 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the duty cycle of the microwave is 50%.

[0093] Example 8

[0094] Example 8 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the intensity of the electric field is 10 kV / m.

[0095] Example 9

[0096] Example 9 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the intensity of the electric field is 100 kV / m.

[0097] Example 10

[0098] Example 10 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the intensity of the magnetic field is 500mT.

[0099] Embodiment 11

[0100] Example 11 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that: in the coupled external field, the intensity of the magnetic field is 1000mT.

[0101] Example 12

[0102] Example 12 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that the coupling external field is a magnetic field and an electric field.

[0103] Example 13

[0104] Example 13 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that the coupling external field is a magnetic field and a microwave field.

[0105] Embodiment 14

[0106] Example 14 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those in Example 1, except that the coupling external field is an electric field and a microwave field.

[0107] Embodiment 15

[0108] This comparative example 1 proposes a solid amine adsorbent pressure swing desorption method, and the steps are basically the same as those of Example 1, except that: no coupling external field is applied.

[0109] Comparative Example 1

[0110] This comparative example 1 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the frequency of the microwave is 1600 MHz.

[0111] Comparative Example 2

[0112] This comparative example 2 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the power of the microwave is 3.5 kW.

[0113] Comparative Example 3

[0114] This comparative example 3 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the duty cycle of the microwave is 65%.

[0115] Comparative Example 4

[0116] This comparative example 4 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the intensity of the electric field is 120 kV / m.

[0117] Comparative Example 5

[0118] This comparative example 5 proposes a solid amine adsorbent pressure swing desorption method, the steps are basically the same as those of Example 1, except that: in the coupled external field, the intensity of the magnetic field is 1200 mT.

[0119] In order to verify the progressiveness of the embodiments of the present application, the desorption temperature of the solid amine adsorbent, the desorption amount of carbon dioxide and the deactivation rate of the solid amine adsorbent in the solid amine adsorbent pressure swing desorption method of the above-mentioned embodiments 1 to 15 and comparative examples 1 to 5 (the data of each external field are summarized as shown in Table 1 below) are experimentally summarized, and the results are shown in Table 2 below.

[0120] Table 1

[0121]

[0122] Note: In Table 1, “×” indicates that no external field is applied, and “-” indicates that the data is the same as that in Example 1.

[0123] Table 2

[0124]

[0125] From Table 2 above, at least the following conclusions can be drawn:

[0126] (1) It can be seen from Examples 1 to 15 that for the recovery rate and enriched gas concentration of carbon dioxide, the data of uncoupled microwaves are lower than those of uncoupled electric fields or uncoupled magnetic fields, that is, microwaves have the greatest promoting effect on the desorption stage of solid amines, and magnetic fields have the least promoting effect on the desorption stage of solid amines. This should be because microwaves can directly act on solid amines and carbon dioxide molecules in the adsorbent, and achieve energy state changes through vibration and rotation to promote the desorption process. The electric field affects the internal structure and electronic movement of the solid amine adsorbent through mechanisms such as polarization and electromigration, but solid amines cannot move freely in the electric field, so the effect of the electric field is limited. Finally, the magnetic field can only affect the movement of charged ions or magnetic particles. It can change the magnetic state of molecules in the adsorbent or induce a magnetic reaction of the adsorbent. This method has a low impact on the adsorbent, resulting in its minimal promoting effect.

[0127] (2) It can be seen from Example 1 and Comparative Example 1 that the frequency of microwaves determines the penetration depth of microwaves. An appropriate microwave frequency will allow the energy to penetrate better into the adsorbent and promote the desorption of the adsorbent. However, if the frequency is too high, the adsorbent will produce a thermal effect, which will cause uneven heat distribution of the adsorbent and deactivate a large amount of solid amine adsorbent, thereby affecting the desorption effect of the adsorbent and reducing the performance of the adsorbent.

[0128] (3) It can be seen from Examples 1, 4, 5 and Comparative Example 2 that microwave power directly affects the energy transfer rate inside the adsorbent. Applying appropriate power can quickly transfer microwave energy to the adsorbent, accelerating the desorption process. However, too high power will cause the adsorbent temperature to rise, and then the solid amine adsorbent will be deactivated in large quantities due to decomposition, ultimately making the recovery rate of carbon dioxide unchanged, but the concentration of the enriched gas decreases due to the inclusion of a large amount of gas after the decomposition of the solid amine.

[0129] (4) By comparing Examples 1, 6, 7 and Comparative Example 3, it can be seen that a suitable duty cycle makes the continuous working time of microwaves appropriate, the energy transmission is large, and the desorption rate is high; while an excessively high duty cycle makes the continuous working time of microwaves too long, resulting in excessive energy transmission, causing the adsorbent to begin to produce a thermal effect, thereby causing a large amount of solid amine adsorbent to be deactivated, resulting in degradation (decomposition) of the adsorbent, thereby reducing the enriched gas concentration due to the inclusion of a large amount of gas after the decomposition of the solid amine.

[0130] (5) By comparing Examples 1, 8, 9 and Comparative Example 4, it can be seen that applying an electric field can increase the surface charge density, weaken the binding force of the adsorbate on the adsorbent surface, and thus facilitate desorption; furthermore, applying an electric field will change the chemical activity of the adsorbent surface, change the active sites on the adsorbent surface, and promote the desorption of the adsorbate. However, applying a higher electric field strength will cause the local temperature of the material to rise sharply, triggering an overheating effect, causing changes in the structure of the solid amine molecules, such as the breaking of intramolecular or intermolecular bonds, resulting in a large amount of inactivation of the solid amine adsorbent, and this effect is irreversible.

[0131] (6) It can be seen from Examples 1, 10, 11 and Comparative Example 5 that the application of a magnetic field can promote the diffusion of carbon dioxide gas molecules, which will indirectly affect the desorption process; furthermore, the application of a magnetic field causes a chemical reaction of electron spins, increases the reactivity of the adsorbent surface, and promotes desorption. However, the application of a magnetic field of too high intensity will cause local heating of the material due to hysteresis loss or the generation of induced current, thereby increasing the temperature of the material, and further causing the solid amine adsorbent to decompose and deactivate in large quantities, thereby reducing the performance of the solid amine adsorbent and the concentration of the enriched gas after desorption.

[0132] (7) As can be seen from Example 15, when only vacuum desorption is used in the embodiment of the present invention, a good recovery rate and a high enriched gas concentration are achieved. Compared with the traditional thermal regeneration method, the vacuum desorption method can basically achieve the regeneration of solid amine at a lower temperature. This pure vacuum desorption method is simple to operate and is conducive to industrial application and promotion.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A solid amine adsorbent pressure swing desorption method, characterized in that: The method comprises the following steps: In a coupled external field, the solid amine adsorbent is desorbed at a desorption temperature; wherein the solid amine adsorbent adsorbs carbon dioxide, and the desorption temperature differs from the adsorption temperature of the solid amine adsorbent by 0°C to 5°C; The coupled external field is microwave, magnetic field and electric field; The solid amine adsorbent is desorbed under vacuum, and the vacuum degree is 10kPa~95kPa; The adsorption temperature is 50°C to 105°C; The intensity of the magnetic field is 500mT~1000mT; The frequency of the microwave is 500MHz~1500MHz; The power of the microwave is 0.6 kW ~ 3.0 kW; The duty cycle of the microwave is 10% to 50%; The intensity of the electric field is 10 kV / m~100 kV / m.

2. The solid amine adsorbent pressure swing desorption method according to claim 1, characterized in that: The relative humidity of the environment in which the solid amine adsorbent is desorbed is 0% to 50%.

3. Application of the solid amine adsorbent pressure swing desorption method as claimed in claim 1 or 2 in the field of carbon capture technology.

Images