Preheating treatment carbon dioxide adsorption system and operation method thereof

Abstract

The invention discloses a preheating treatment carbon dioxide adsorption system and an operation method thereof, and belongs to the technical field of energy storage and chemical process equipment. The problems of high heat consumption, low heat conductivity and slow heating of the adsorbent in the prior art are solved. The technical key points are as follows: the temperature of the system is slowly increased at the initial stage of heating, part of carbon dioxide is desorbed, the carbon dioxide is heated by high-temperature heat exchange equipment and then flows back to the tower body of the adsorption tower, and the heating process can be completed in idle time except energy storage-energy release due to the fact that the compressed gas energy storage system implements discontinuous energy storage-energy release. Good adsorption and desorption effects can be realized in a relatively low temperature range, so that the energy demand in the heating and cooling process is reduced, the overall energy consumption of the system is reduced, the heat exchange pressure of the heating system is relieved, and the demand on the heat exchange power of heating equipment is relieved; the gas pressure in the adsorption tower body is slightly increased, so that continuous and stable release and supply of carbon dioxide of an adsorption system are guaranteed, and the method has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and chemical process equipment, and in particular to a preheating treatment carbon dioxide adsorption system and an operation method thereof. Background Art

[0002] Compressed gas energy storage technology can realize time-sharing storage and release of energy, and is considered to be a key supporting technology for expanding the scale of renewable energy utilization. Among them, carbon dioxide energy storage technology, as a new energy storage solution, has received attention at home and abroad because of its advantages such as simple process and high cycle efficiency. As a greenhouse gas, carbon dioxide needs to circulate in a closed system. Among the mainstream gaseous, liquid and adsorbed low-pressure storage methods, adsorbed storage has been widely studied due to its advantages such as low storage pressure (normal temperature and pressure) and small space occupation.

[0003] Carbon dioxide is usually stored in the adsorption system by two methods: temperature change and pressure change. The pressure change consumes a lot of electricity, making the energy storage system's electric-electric efficiency lower than expected. Fluctuations in parameters such as the pressure, flow rate and composition of the raw gas will have a significant impact on the adsorption effect, requiring the raw gas to be relatively stable. The strength and stability of the adsorbent are required to be high. Therefore, temperature swing adsorption has attracted widespread attention.

[0004] However, temperature swing adsorption still has many limitations. It requires frequent heating and cooling of the adsorption bed. The heating process consumes a lot of heat energy, and the cooling process requires additional cooling media and equipment, resulting in high overall energy consumption. The heating and cooling processes are relatively slow, the adsorption and desorption processes take a long time, the entire operation cycle is long, and the equipment processing capacity is relatively limited.

[0005] Therefore, it is urgent to propose a preheating treatment carbon dioxide adsorption system and an operation method thereof to solve the problems of large heat consumption, low thermal conductivity and slow heating of the adsorbent in the prior art. Summary of the invention

[0006] In view of the above facts, in order to solve the problems of large heat consumption, low thermal conductivity and slow heating of the adsorbent in the prior art, the present invention further designs a preheating treatment carbon dioxide adsorption system and an operation method thereof.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] Solution 1: A preheating treatment carbon dioxide adsorption system, including an adsorption tower body, an adsorbent, a flow pressure control device, an air pump, a high-temperature heat exchange device, and a flexible buffer air bag;

[0009] The turbine outlet pipeline is connected to the adsorption end of the adsorption tower body, and the desorption end of the adsorption tower body is connected to the air pump and the flexible buffer air bag in sequence through the compressor inlet pipeline;

[0010] The air pump and the flexible buffer airbag are connected to the input end of the return pipe, the output end of the return pipe is connected to the turbine outlet pipe, and a high-temperature heat exchange device is installed on the return pipe;

[0011] The adsorbent is placed in the adsorption tower body;

[0012] The flow pressure control device is installed between the adsorption tower body and the air pump.

[0013] Scheme 2: A method for operating a preheating carbon dioxide adsorption system, which is implemented based on a preheating carbon dioxide adsorption system described in Scheme 1, and the operation process is:

[0014] Step 1: Adsorption: Carbon dioxide enters the adsorption tower from the turbine outlet pipe, and the adsorbent adsorbs carbon dioxide;

[0015] Step 2: Preheating: In the early stage of preheating, the system temperature rises slowly, and the slow desorption of carbon dioxide cannot meet the flow demand of the compressor inlet. The operation of the air pump causes partial desorption of carbon dioxide, which is heated by the high-temperature heat exchange equipment and then flows back to the adsorption tower body. The heating process can be completed in the idle time outside the energy storage-release time.

[0016] Step 3: Desorption: After flow control, the desorbed carbon dioxide is supplied to the compressor at a stable mass flow rate through the flexible buffer airbag, completing the carbon dioxide energy storage process.

[0017] Furthermore: in the step 1, the internal environment of the adsorption tower is 25° C., 1 atm, and the carbon dioxide adsorption capacity of the adsorbent is 1 to 10 mmol / g.

[0018] Furthermore: in the step 1, carbon dioxide is injected into the adsorption tower body at a fixed flow rate or a variable flow rate of 0 to 1000 kg / s, the temperature is -50°C to 30°C, and the pressure is 0 to 2 MPa.

[0019] Furthermore: in the step 2, the air pump operating flow rate varies in the range of 0 to 300 kg / s.

[0020] Furthermore: in the step 2, the high temperature heat exchange equipment is electric heating or steam or molten salt heating, the temperature is 50°C to 600°C, and the temperature of the obtained high temperature carbon dioxide gas is 50°C to 300°C.

[0021] Further: In step 3, the volume of the flexible cushioning airbag is 10 to 1000 m 3 .

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention solves the heating delay problem caused by large heat consumption and low thermal conductivity of the adsorbent by preheating during the idle period of the system, which greatly alleviates the heat exchange pressure of the heating system and the demand for the heat exchange power of the heating equipment (reflected in the temperature and flow rate of the heat exchange medium).

[0024] 2. In the present invention, the temperature inside the adsorption tower increases, which slightly increases the gas pressure in the system, ensuring the continuous and stable release and supply of carbon dioxide in the adsorption system at a high flow rate, and has good prospects for industrial application.

[0025] 3. The present invention can accelerate the diffusion rate of adsorbate molecules on the adsorbent surface, allowing the adsorbate to combine with the active sites of the adsorbent more quickly, thereby shortening the time to reach adsorption equilibrium. More target substances can be adsorbed within the same adsorption time, thereby improving adsorption efficiency and enhancing adsorbent activity.

[0026] 4. The present invention can keep the adsorbent at a relatively high temperature before the secondary adsorption, and can better overcome the influence of the adsorption heat during the adsorption process, making the adsorption process closer to an ideal state.

[0027] 5. The present invention helps the system to reach a relatively stable operating state during the startup phase, reduces changes in system performance caused by factors such as temperature fluctuations, improves the reliability and stability of the system, and ensures the continuity of the adsorption process and the stability of product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the adsorption system in the present invention;

[0029] Figure 2 It is a schematic diagram of the points in the adsorption system (the adsorbent is placed within the dotted line);

[0030] Figure 3 The temperature change diagram of each area of ​​the adsorption system at different operating temperatures, including (a) the temperature change diagram of the adsorption system at 100°C; (b) the temperature change diagram of the adsorption system at 150°C; (c) the temperature change diagram of the adsorption system at 200°C;

[0031] Figure 4 Figure 3 is a graph showing changes in the carbon dioxide desorption efficiency in each region of the adsorption system, including (a) a graph showing changes in the carbon dioxide desorption efficiency in each region of the adsorption system at 100°C; (b) a graph showing changes in the carbon dioxide desorption efficiency in each region of the adsorption system at 150°C; (c) a graph showing changes in the carbon dioxide desorption efficiency in each region of the adsorption system at 200°C; and (d) a graph showing changes in the carbon dioxide desorption efficiency in each region of the adsorption system under preheating-desorption.

[0032] In the figure: 1-adsorption tower body, 2-adsorbent, 3-flow pressure control device, 4-air pump, 6-high temperature heat exchange equipment, 7-turbine outlet pipe, 8-flexible buffer air bag, 9-compressor inlet pipe. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] In the present application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "back", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0036] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0037] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Embodiment 1: A preheating treatment carbon dioxide adsorption system of this embodiment includes an adsorption tower body 1, an adsorbent 2, a flow pressure control device 3, an air pump 4, a high-temperature heat exchange device 6, and a flexible buffer air bag 8;

[0041] The turbine outlet pipe 7 is connected to the adsorption end of the adsorption tower body 1, and the desorption end of the adsorption tower body 1 is connected to the air pump 4 and the flexible buffer air bag 8 in sequence through the compressor inlet pipe 9;

[0042] The air pump 4 and the flexible buffer airbag 8 are connected to the input end of the return pipe, the output end of the return pipe is connected to the turbine outlet pipe 7, and a high-temperature heat exchange device 6 is installed on the return pipe;

[0043] The adsorbent 2 is placed in the adsorption tower body 1;

[0044] The flow pressure control device 3 is installed between the adsorption tower body 1 and the air pump 4 .

[0045] Embodiment 2: The operation method of a preheating treatment carbon dioxide adsorption system of this embodiment is realized by relying on the preheating treatment carbon dioxide adsorption system described in Embodiment 1, and the operation process is as follows:

[0046] Step 1: Adsorption: Carbon dioxide enters the adsorption tower body 1 from the turbine outlet pipe 7, and the adsorbent 2 adsorbs carbon dioxide;

[0047] Step 2: Preheating: In the early stage of preheating, the system temperature rises slowly, and the slow desorption of carbon dioxide cannot meet the flow demand of the compressor inlet. The operation of the air pump 4 causes partial desorption of carbon dioxide, which is heated by the high-temperature heat exchange device 6 and then flows back to the adsorption tower body 1. Since the compressed gas energy storage system implements discontinuous energy storage-release, the heating process can be completed in the idle time outside the energy storage-release;

[0048] Step 3: Desorption: After flow control, the desorbed carbon dioxide is supplied to the compressor at a stable mass flow rate through the flexible buffer airbag 8, completing the energy storage process of carbon dioxide.

[0049] More specifically: in the step 1, the adsorbent 2 includes one or a mixture of common adsorbents such as carbon-based adsorbents, zeolite molecular sieves, silica gel, etc.;

[0050] More specifically: in the step 1, the environment inside the adsorption tower body 1 is 25° C., 1 atm, and the carbon dioxide adsorption capacity in the adsorbent 2 is 1 to 10 mmol / g.

[0051] More specifically: in the step 1, carbon dioxide is injected into the adsorption tower body 1 at a fixed flow rate or a variable flow rate of 0 to 1000 kg / s, the temperature is -50°C to 30°C, and the pressure is 0 to 2 MPa.

[0052] More specifically: in the step 1, the adsorption tower is a single tower or a multi-tower arrangement.

[0053] More specifically: in the step 2, the adsorption system is heated to a predetermined temperature, and the pressure of carbon dioxide in the adsorption system increases, and the increase is affected by the preheating temperature.

[0054] More specifically: in step 2, the flow rate of the air pump 4 varies within a range of 0 to 300 kg / s.

[0055] More specifically: in the step 2, the high-temperature heat exchange equipment 6 is electrically heated or steam or molten salt heated at a temperature of 50°C to 600°C, and the temperature of the obtained high-temperature carbon dioxide gas is 50°C to 300°C, which is used to heat the adsorbent 2 in the adsorption tower body 1 to a predetermined temperature through gas-solid heat exchange.

[0056] More specifically: in step 3, the volume of the flexible cushioning airbag 8 is 10 to 1000 m 3 , ensuring the stable pressure and flow of carbon dioxide at the compressor inlet.

[0057] More specifically: The experimental equipment can be replaced by:

[0058] The adsorption tower body 1 can be coupled with a high-temperature heat exchange device 6, that is, heat is directly supplied inside the adsorption tower body 1 by means of electric heating, steam heating or molten salt heating;

[0059] The air pump 4 can be replaced by a vacuum pump, or the air pump 4 can be combined with a vacuum pump to improve the carbon dioxide desorption efficiency of the system;

[0060] The flexible buffer airbag 8 can be replaced with a gas storage unit such as a small adsorption tower to stabilize the output flow and output pressure of carbon dioxide.

[0061] Comparative Example 1: Step 1: Adsorption: Carbon dioxide at 25°C enters the adsorption tower body 1 from the turbine outlet pipe 7 at 0.3 kg / s, and the adsorbent 2 adsorbs the carbon dioxide;

[0062] Step 2: Desorption: The temperature of the heated carbon dioxide is 100°C, and it flows back into the adsorption tower body 1 at 0.3kg / s to induce desorption and emission of carbon dioxide in the adsorption tower body 1, and the outlet pressure is controlled at 1atm;

[0063] Since the temperature of the introduced carbon dioxide was 100°C, this operation method was named 100°C.

[0064] Comparative Example 2: Step 1: Adsorption: Carbon dioxide at 25°C enters the adsorption tower body 1 from the turbine outlet pipe 7 at 0.3 kg / s, and the adsorbent 2 adsorbs the carbon dioxide;

[0065] Step 2: Desorption: The temperature of the heated carbon dioxide is 150°C, and it flows back into the adsorption tower body 1 at a rate of 0.3 kg / s to induce desorption and emission of carbon dioxide in the adsorption tower body 1, and the outlet pressure is controlled at 1 atm;

[0066] Since the temperature of the introduced carbon dioxide is 150°C, this operation method is named 150°C.

[0067] Comparative Example 3: Step 1: Adsorption: Carbon dioxide at 25°C enters the adsorption tower body 1 from the turbine outlet pipe 7 at 0.3 kg / s, and the adsorbent 2 adsorbs the carbon dioxide;

[0068] Step 2: Desorption: The temperature of the heated carbon dioxide is 200°C, and it flows back into the adsorption tower body 1 at 0.3kg / s to induce desorption and emission of carbon dioxide in the adsorption tower body 1, and the outlet pressure is controlled at 1atm;

[0069] Since the temperature of the introduced carbon dioxide is 200°C, this operation method is named 200°C.

[0070] Comparative Example 4: Step 1: Adsorption: Carbon dioxide at 25°C enters the adsorption tower body 1 from the turbine outlet pipe 7 at 0.3 kg / s, and the adsorbent 2 adsorbs the carbon dioxide;

[0071] Step 2: Preheating: Use the air pump 4 to transport the carbon dioxide, and make the circulating carbon dioxide reach a temperature of 200° C. through the high-temperature heat exchange device 6, and heat the adsorbent in the adsorption tower body 1 to 200° C.;

[0072] Step 3: Desorption: Without the need for carbon dioxide to flow in, the carbon dioxide stored in the adsorption tower body 1 is desorbed and discharged at a pressure of 1 atm through a pressure reducing valve;

[0073] Due to the addition of a preheating step, this run method was named preheating-desorption.

[0074] By comparing the above methods with numerical simulation, it can be found that the desorption of carbon dioxide in adsorbent 2 is limited by the thermal conductivity of adsorbent 2 and the circulating carbon dioxide flow rate. Under the conditions of 25°C and 0.3kg / s of carbon dioxide, the system heating time reaches 450min (7.5h), and the energy storage time of the adsorption system is greatly limited. In addition, increasing the heating temperature does not significantly shorten the overall heating time of the system. Therefore, slow heating is an important bottleneck problem restricting the application of the adsorption system.

[0075] In contrast, in the desorption stage, since the desorption efficiency of carbon dioxide in adsorbent 2 is only affected by pressure and temperature, under normal pressure desorption conditions, the desorption efficiency of carbon dioxide is only affected by the desorption temperature;

[0076] In the desorption stage, the carbon dioxide desorption at various locations in Comparative Examples 1-3 is carried out step by step. At 100°C, 150°C and 200°C, the carbon dioxide desorption efficiencies are 60%, 72% and 82%, respectively; and the carbon dioxide desorption after preheating is global desorption. Under the action of high pressure (about 1.1MPa) after heating, if the flow rate is not controlled, the carbon dioxide in the system can be completely released within 80s (affected by the desorption endothermic effect, the temperature of the adsorption tower body 1 after desorption is reduced to 180°C, and the desorption efficiency is 80%). The carbon dioxide desorption rate is increased by more than 300 times, which can fully meet the demand of the energy storage system for carbon dioxide flow supply.

[0077] Since heating is only performed during idle time, during the preheating process of the adsorption system, the quality and temperature of the heating heat source and the flow rate of the air pump 4 are no longer stringent, and it has a high prospect for industrial application.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. As long as there is no structural conflict, the various features in the specific implementation methods disclosed in this application can be combined with each other in any way, and the essence of the corresponding technical solutions will not deviate from the scope of the technical solutions of the present invention.

[0079] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A preheating treatment carbon dioxide adsorption system, characterized in that: It comprises an adsorption tower body (1), an adsorbent (2), a flow pressure control device (3), an air pump (4), a high-temperature heat exchange device (6), and a flexible buffer air bag (8); The turbine outlet pipe (7) is connected to the adsorption end of the adsorption tower body (1), and the desorption end of the adsorption tower body (1) is connected to the air pump (4) and the flexible buffer air bag (8) in sequence through the compressor inlet pipe (9); The air pump (4) and the flexible buffer airbag (8) are connected to the input end of the return pipe, the output end of the return pipe is connected to the turbine outlet pipe (7), and a high-temperature heat exchange device (6) is installed on the return pipe; The adsorbent (2) is placed in the adsorption tower body (1); The flow rate and pressure control device (3) is installed between the adsorption tower body (1) and the air pump (4).

2. A method for operating a preheating treatment carbon dioxide adsorption system, which is implemented by relying on the preheating treatment carbon dioxide adsorption system according to claim 1, characterized in that: The operation process is: Step 1: Adsorption: Carbon dioxide enters the adsorption tower body (1) from the turbine outlet pipe (7), and the adsorbent (2) adsorbs the carbon dioxide; Step 2: Preheating: In the initial stage of preheating, the system temperature rises slowly, and the slow desorption of carbon dioxide cannot meet the flow demand of the compressor inlet. The operation of the air pump (4) causes partial desorption of carbon dioxide, which is heated by the high-temperature heat exchange device (6) and then flows back to the adsorption tower body (1). The heating process can be completed in the idle time outside the energy storage-release process. Step 3: Desorption: After flow control, the desorbed carbon dioxide is supplied to the compressor at a stable mass flow rate through the flexible buffer airbag (8), completing the carbon dioxide energy storage process.

3. The method for operating a preheat treatment carbon dioxide adsorption system according to claim 2, characterized in that: In the step 1, the internal environment of the adsorption tower body (1) is 25°C and 1 atm, and the carbon dioxide adsorption capacity of the adsorbent (2) is 1 to 10 mmol / g.

4. The method for operating a preheat treatment carbon dioxide adsorption system according to claim 2, characterized in that: In the step 1, carbon dioxide is injected into the adsorption tower body (1) at a fixed flow rate or a variable flow rate of 0 to 1000 kg / s, the temperature is -50°C to 30°C, and the pressure is 0 to 2 MPa.

5. The method for operating a preheat treatment carbon dioxide adsorption system according to claim 2, characterized in that: In step 2, the air pump (4) operates with a flow rate ranging from 0 to 300 kg / s.

6. The method for operating a preheat treatment carbon dioxide adsorption system according to claim 2, characterized in that: In the step 2, the high temperature heat exchange equipment (6) is electrically heated or heated by steam or molten salt, and the temperature is 50°C to 600°C, and the temperature of the obtained high temperature carbon dioxide gas is 50°C to 300°C.

7. The method for operating a preheat treatment carbon dioxide adsorption system according to claim 2, characterized in that: In step 3, the volume of the flexible cushioning airbag (8) is 10 to 1000 m 3 .

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