Carbon dioxide search system and method

Abstract

The invention relates to a carbon dioxide searching system and method, and the system comprises a reactor which is provided with a flue gas input end, a gaseous substance output end, a return ash input end, a calcium-based absorbent input end, a heat input end, and a thermometer installation end; a flue gas input part; the gas recovery part comprises a dust remover and a gas recovery treatment assembly; the gas output end of the dust remover is connected with the gas recovery processing assembly, the gas input end of the dust remover is connected with the gaseous substance output end through a gas output pipeline assembly, and the returned ash output end of the dust remover is connected with the returned ash input end through a returned ash pipeline assembly; the jet device is provided with an output end, a first input end and a second input end; the first input end is used for being connected with a calcium-based absorbent supply device, the second input end is connected with the gas output pipeline assembly through the flow dividing pipeline assembly, and the device has the advantages that high-concentration carbon dioxide is obtained, capital investment during system construction is reduced, and the improvement cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a carbon dioxide capture system and method. Background Art

[0002] Coal-fired power plants are major emitters of carbon dioxide. Carbon dioxide capture, utilization and storage (CCUS) is one of the effective methods to reduce carbon dioxide on a large scale. At present, for coal-fired units, carbon dioxide capture technologies mainly include:

[0003] (1) Decarbonization before combustion: coal is converted into syngas using coal gasification technology, and then the carbon monoxide is converted into carbon dioxide for capture;

[0004] (2) Decarbonization during combustion, directly using high-concentration oxygen to participate in the combustion reaction to obtain high-concentration carbon dioxide for capture;

[0005] (3) Post-combustion decarbonization: separation and recovery of flue gas carbon dioxide in the tail gas of coal-fired units. The main post-combustion decarbonization methods are physical and chemical methods.

[0006] Calcium-based absorption and desorption capture of carbon dioxide belongs to the post-combustion chemical decarbonization technology. At present, the mainstream calcium-based capture of carbon dioxide technology mainly adopts a double-reaction double-cycle decarbonization process. Its main process includes: flue gas and CaO (calcium-based absorbent) remove carbon dioxide in the carbonation reactor (carbon dioxide absorption reactor), generate gas phase and discharge, solid phase (CaCO 3 ) enters the calcination reactor (carbon dioxide desorption reactor) to generate high-purity carbon dioxide gas for capture, and generates solid phase CaO which returns to the carbonation reactor (carbon dioxide absorption reactor) as an absorbent for reaction.

[0007] For this type of double-reaction double-cycle decarbonization process, in the absorption stage (carbonation reaction stage), the flue gas and CaO react at a carbonation temperature of about 650°C; in the desorption stage (calcination reaction stage), CaCO 3 The calcination temperature is about 950℃. High temperature materials CaO, CaCO 3 Transporting between two reactors is a difficult problem in the industry. In addition, the dual reactors require a large investment, occupy a large area, and have high operation and maintenance costs, which means that this technology has not yet been applied on a large scale. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a carbon dioxide capture system and method.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A carbon dioxide capture system, comprising:

[0011] The reactor has a flue gas input end, a gaseous material output end, a return ash input end, a calcium-based absorbent input end, a heat input end for connecting to an external heat source conveying device, and a thermometer installation end for inserting a thermometer;

[0012] A smoke input part connected to the smoke input end;

[0013] The gas recovery unit includes a dust collector and a gas recovery processing assembly; the gas output end of the dust collector is connected to the gas recovery processing assembly, the gas input end of the dust collector is connected to the gaseous material output end through a gas output pipeline assembly, and the return ash output end of the dust collector is connected to the return ash input end through a return ash pipeline assembly;

[0014] The ejector has an output end, a first input end and a second input end; the output end is connected to the calcium-based absorbent input end through a calcium-based absorbent delivery pipeline assembly; the first input end is used to be connected to a calcium-based absorbent supply device, and the second input end is connected to the gas output pipeline assembly through a diverter pipeline assembly, and delivers gas of a preset pressure to the ejector to deliver the calcium-based absorbent to the reactor.

[0015] Preferably, the gas output pipeline assembly comprises a first pipe, a compressor, a second pipe and a gas collecting valve;

[0016] The gas output end, the first pipe, the compressor, the second pipe and the gas input end of the dust collector are connected in sequence, and the gas collection valve is arranged on the second pipe;

[0017] The shunt pipeline assembly includes a shunt pipe and a circulating gas valve arranged on the shunt pipe. One end of the shunt pipe is connected to the output end of the compressor, and the other end is connected to the second input end.

[0018] Preferably, it further comprises a high temperature heat exchanger, wherein the high temperature heat exchanger is located upstream of the compressor;

[0019] and / or,

[0020] It also includes a low-temperature heat exchanger, which is located upstream of the dust collector and downstream of the circulating gas valve.

[0021] Preferably, it also includes:

[0022] A high-temperature heat exchanger having a first high-temperature heat exchange channel and a second high-temperature heat exchange channel, wherein the first high-temperature heat exchange channel is connected to a pipe section of the gas output pipeline assembly close to one end of the gaseous material output end, and the second high-temperature heat exchange channel is connected to the calcium-based absorbent delivery pipeline assembly;

[0023] and / or,

[0024] The low-temperature heat exchanger has a first low-temperature heat exchange channel and a second low-temperature heat exchange channel. The first low-temperature heat exchange channel is connected to the pipe section of the gas output pipeline assembly away from the gas output end, and the second low-temperature heat exchange channel is connected to the return ash pipeline assembly.

[0025] Preferably, the smoke input part includes an original smoke pipe, an original smoke valve and an original smoke analyzer;

[0026] The original smoke pipe is connected to the smoke input end, and the original smoke valve and the original smoke analyzer are both installed on the original smoke pipe;

[0027] The gas recovery and processing assembly includes a carbon dioxide collection pipe, a carbon dioxide collection control valve, a clean flue gas discharge pipe, a clean flue gas valve and a clean flue gas analyzer;

[0028] The carbon dioxide collection control valve is installed on the carbon dioxide collection pipe, and the clean smoke valve is installed on the clean smoke exhaust pipe;

[0029] The clean flue gas analyzer is installed upstream of the carbon dioxide collection control valve and the clean flue gas valve.

[0030] A carbon dioxide capture method based on the above carbon dioxide capture system comprises the following steps:

[0031] System startup preparation, including conveying raw flue gas into the reactor;

[0032] pressurizing the gas output from the reactor to a preset pressure and delivering the gas to the ejector, so as to deliver the calcium-based absorbent delivered to the ejector to the reactor;

[0033] transporting the return ash output from the gas recovery unit to the reactor;

[0034] Controlling the reactor to be in a carbonation reaction state;

[0035] The operation state of the reactor is controlled to switch from the carbonation reaction state to the calcination reaction state. When the carbon dioxide concentration in the clean flue gas discharged from the gas recovery unit after calcination reaches a preset collection concentration, the gas output from the reactor is collected.

[0036] Preferably, the method further includes the following steps: using a high-temperature heat exchanger to perform heat exchange between the calcium-based absorbent and the gas output from the reactor; and / or using a low-temperature heat exchanger to perform heat exchange between the return ash output from the dust collector and the gas output from the compressor.

[0037] Preferably, the system startup preparation step includes:

[0038] When the reactor is heated to a preset temperature, the original smoke valve, the collection gas valve, and the clean smoke valve are opened to allow the smoke of the entire system to flow in a balanced manner for a preset time;

[0039] When the compressor output gas pressure reaches the preset pressure, the circulating gas valve is opened.

[0040] Preferably, the controlling the operating state of the reactor to switch from the carbonation reaction state to the calcination reaction state specifically comprises the following steps:

[0041] After the carbonation reaction continues for a preset reaction time, the raw flue gas is stopped from being delivered to the reactor, and it is determined whether the carbon dioxide concentration of the gas output from the gas recovery unit is not greater than the standard switching concentration. If so, the state is switched, and if not, the carbon dioxide absorption state is maintained;

[0042] or,

[0043] After the carbonation reaction continues for a preset reaction time, the calcium-based absorbent is stopped from being delivered to the reactor, and the state is directly switched.

[0044] Preferably, the method further comprises the following steps:

[0045] Calculate the carbon dioxide removal efficiency based on the carbon dioxide concentration in the original flue gas and the carbon dioxide concentration in the clean flue gas discharged from the gas recovery unit;

[0046] Determine whether the carbon dioxide removal efficiency is lower than the removal efficiency set value. If so, replace the calcium-based absorbent in the reactor.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The above scheme provides a carbon dioxide capture system, which is provided with a flue gas input end, a gaseous material output end, a return ash input end, a calcium-based absorbent input end, a heat input end and a thermometer installation end through the reactor, which can not only realize the reuse of the return ash and the supplement of the calcium-based absorbent to meet the target requirements of collecting high-purity carbon dioxide; but also can regulate the temperature of the reactor so that the carbonation reaction and the calcination reaction can be completed in the same reactor, thereby effectively solving the problem of the difficulty and high cost of high-temperature material transportation caused by the carbonation reaction and the calcination reaction being carried out in different reactors in the prior art scheme, and can effectively reduce the capital investment in system construction and reduce the system transformation cost. In addition, the ejector directly uses the gas with a preset pressure in the system to transport the calcium-based absorbent to the reactor, which can reduce the supply of external kinetic energy, and further achieve the purpose of saving energy, reducing the cost of use and reducing the manufacturing cost. Correspondingly, the carbon dioxide capture method based on the above carbon dioxide capture system provided by the above scheme has the advantages of obtaining high-concentration carbon dioxide, reducing capital investment in system construction, and reducing system transformation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 A schematic diagram of the structure of one example of the system provided by the present invention.

[0051] Figure 2 for Figure 1 Schematic diagram of the system at the startup stage (gas balance flow state in the system).

[0052] Figure 3 for Figure 1 Schematic diagram of the system in the carbonation reaction state.

[0053] Figure 4 for Figure 1 Schematic diagram of the system in the calcination reaction state.

[0054] Description of reference numerals:

[0055] 100, gas output pipeline assembly; 101, first pipe; 102, compressor; 103, second pipe; 104, collecting gas valve; 200, return ash pipeline assembly; 201, return ash pipe; 202, return ash fan; 300, calcium-based absorbent delivery pipeline assembly; 400, shunt pipeline assembly; 401, shunt pipe; 402, circulating gas valve; 500, waste residue discharge pipeline assembly; 501, waste residue discharge pipe; 502, slag discharge valve; 600, calcium-based absorbent supply pipeline assembly; 601, calcium-based absorbent supply pipe; 602, calcium-based absorbent feeding valve; 1, reactor; 11, flue gas input end; 12, gaseous material output end; 13, return ash input end; 14, calcium-based absorbent input end ; 15. Heat input end; 16. Thermometer installation end; 17. Waste residue discharge end; 2. Flue gas input part; 21. Original flue gas pipe; 22. Original flue gas valve; 23. Original flue gas analyzer; 3. Gas recovery part; 31. Dust collector; 32. Gas recovery and processing component; 321. Carbon dioxide collection pipe; 322. Carbon dioxide collection control valve; 323. Clean flue gas discharge pipe; 324. Clean flue gas valve; 325. Clean flue gas analyzer; 4. Ejector; 40. Output end; 41. First input end; 42. Second input end; 5. High-temperature heat exchanger; 51. First high-temperature heat exchange channel; 52. Second high-temperature heat exchange channel; 6. Low-temperature heat exchanger; 61. First low-temperature heat exchange channel; 62. Second low-temperature heat exchange channel. DETAILED DESCRIPTION

[0056] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0058] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] See also Figures 1 to 4 An embodiment of the present invention provides a carbon dioxide capture system, including a reactor 1, a flue gas input part 2, a gas recovery part 3 and an ejector 4.

[0060] Specifically, the reactor 1 has a flue gas input end 11, a gaseous material output end 12, a return ash input end 13, a calcium-based absorbent input end 14, a heat input end 15 for connecting to an external heat source conveying device, and a thermometer mounting end 16 for inserting a thermometer. The flue gas input part 2 is connected to the flue gas input end 11 and is used to convey raw flue gas to the flue gas input end 11. The gas recovery section 3 includes a dust collector 31 and a gas recovery processing component 32; the gas output end of the dust collector 31 is connected to the gas recovery processing component 32, the gas input end of the dust collector 31 is connected to the gas output end 12 through the gas output pipeline component 100, and the return ash output end of the dust collector 31 is connected to the return ash input end 13 through the return ash pipeline component 200; it can be known that the gas output from the gas output end 12 of the reactor 1 is first dedusted by the dust collector 31 and then transported to the gas recovery processing component 32, and the return ash output from the dust collector 31 can be transported back to the reactor 1 through the return ash pipeline component 200 as a reaction raw material for the reactor 1. The ejector 4 has an output end 40, a first input end 41 and a second input end 42; the output end 40 is connected to the calcium-based absorbent input end 14 through a calcium-based absorbent delivery pipeline assembly 300; the first input end 41 is used to be connected to a supply device for the calcium-based absorbent, and the second input end 42 is connected to the gas output pipeline assembly 100 through a diverter pipeline assembly 400, and delivers gas of a preset pressure to the ejector 4 to deliver the calcium-based absorbent to the reactor 1.

[0061] Through the above scheme, the reactor 1 is provided with a flue gas input end 11, a gaseous material output end 12, a return ash input end 13, a calcium-based absorbent input end 14, a heat input end 15 and a thermometer installation end 16, which can not only realize the reuse of the return ash and the supplement of the calcium-based absorbent to meet the target requirement of collecting high-purity carbon dioxide; but also can regulate the temperature of the reactor 1 so that the carbonation reaction and the calcination reaction can be completed in the same reactor 1, thereby effectively solving the problem of the difficulty and high cost of high-temperature material transportation caused by the carbonation reaction and the calcination reaction being carried out in different reactors 1 in the prior art scheme, and can effectively reduce the capital investment in system construction and reduce the system transformation cost. In addition, the ejector 4 directly uses the gas with a preset pressure in the system to transport the calcium-based absorbent to the reactor 1, which can reduce the supply of external kinetic energy, and further achieve the purpose of saving energy, reducing the use cost and reducing the manufacturing cost.

[0062] It can be known that the temperature in the reactor 1 can be controlled by the external heat source delivery device connected to the heat input end 15 and the thermometer inserted into the thermometer installation end 16. When a carbonation reaction occurs in the reactor 1, the temperature in the reactor 1 can be controlled to be maintained at a first preset temperature (generally set to about 650°C); when a calcination reaction occurs in the reactor 1, the temperature in the reactor 1 can be controlled to be maintained at a second preset temperature (generally set to about 950°C).

[0063] Further, the gas output pipeline assembly 100 includes a first pipe 101, a compressor 102, a second pipe 103 and a collecting gas valve 104; the gas output end 12, the first pipe 101, the compressor 102, the second pipe 103 and the gas input end of the dust collector 31 are connected in sequence, and the collecting gas valve 104 is arranged on the second pipe 103; the shunt pipeline assembly 400 includes a shunt pipe 401 and a circulating gas valve 402 arranged on the shunt pipe 401, one end of the shunt pipe 401 is connected to the output end of the compressor 102, and the other end is connected to the second input end 42; through the cooperation of the collecting gas valve 104, the circulating gas valve 402 and the compressor 102, the gas at a preset pressure can be delivered to the ejector 4.

[0064] In order to ensure that the dust collector 31 and the compressor 102 operate stably within a safe temperature, in this embodiment, a high-temperature heat exchanger 5 and a low-temperature heat exchanger 6 are also included. The high-temperature heat exchanger 5 is located upstream of the compressor 102; the low-temperature heat exchanger 6 is located upstream of the dust collector 31 and downstream of the circulating gas valve 402, thereby ensuring that the circulating gas delivered to the ejector 4 has a certain temperature to preheat the calcium-based absorbent. Of course, in other embodiments, any one of the high-temperature heat exchanger 5 and the low-temperature heat exchanger 6 can also be set, and multiple heat exchangers can also be set.

[0065] Specifically, the high-temperature heat exchanger 5 has a first high-temperature heat exchange channel 51 and a second high-temperature heat exchange channel 52. The first high-temperature heat exchange channel 51 is connected to the pipe section of the gas output pipeline assembly 100 close to the gas output end 12, and the second high-temperature heat exchange channel 52 is connected to the calcium-based absorbent transport pipeline assembly 300.

[0066] Specifically, the low-temperature heat exchanger 6 has a first low-temperature heat exchange channel 61 and a second low-temperature heat exchange channel 62. The first low-temperature heat exchange channel 61 is connected to the pipe section of the gas output pipeline assembly 100 away from the gas output end 12, and the second low-temperature heat exchange channel 62 is connected to the return ash pipeline assembly 200. On the one hand, the step-by-step utilization of the heat of the exhaust gas in the reactor 1 can be achieved, and on the other hand, the calcium-based absorbent and return ash put into the reactor 1 can be preheated, so that the calcium-based absorbent and return ash put into the reactor 1 can be evenly heated to the preset reaction temperature.

[0067] In order to facilitate the monitoring of the carbon dioxide concentration of the original flue gas (the flue gas from the desulfurization outlet) and the clean flue gas (the flue gas after the dust removal by the dust collector 31), in this embodiment, the flue gas input part 2 includes an original flue gas pipe 21, an original flue gas valve 22 and an original flue gas analyzer 23; the original flue gas pipe 21 is connected to the flue gas input end 11, and the original flue gas valve 22 and the original flue gas analyzer 23 are both installed on the original flue gas pipe 21; the gas recovery and processing component 32 includes a carbon dioxide collection pipe 321, a carbon dioxide collection control valve 322, a clean flue gas exhaust pipe 323, a clean flue gas valve 324 and a clean flue gas analyzer 325; the carbon dioxide collection control valve 322 is installed on the carbon dioxide collection pipe 321, and the clean flue gas valve 324 is installed on the clean flue gas exhaust pipe 323; the clean flue gas analyzer 325 is installed upstream of the carbon dioxide collection control valve 322 and the clean flue gas valve 324.

[0068] It can be known that, in the process of carbonation reaction (i.e., reactor 1 is in the carbon dioxide absorption state), the clean flue gas carbon dioxide concentration can be monitored by the clean flue gas analyzer 325, and then the absorption degree of carbon dioxide in the original flue gas can be judged, and further the running state of whether the reactor 1 can be switched can be judged. In the process of calcination reaction (i.e., reactor 1 is in the carbon dioxide desorption state), the clean flue gas carbon dioxide concentration can be monitored by the clean flue gas analyzer 325, and then it can be judged when the clean flue gas is collected to obtain high-purity carbon dioxide. In addition, the concentration of the original flue gas can be measured by the original flue gas analyzer 23, and the clean flue gas analyzer 325 can measure the concentration of the clean flue gas, and then the removal efficiency of carbon dioxide can be calculated in the process of carbonation reaction (i.e., reactor 1 is in the carbon dioxide absorption state), and then the performance of the calcium-based absorbent in the reactor 1 can be judged.

[0069] Specifically, the removal efficiency of carbon dioxide can be calculated using the following formula:

[0070]

[0071] Where, η is the carbon dioxide removal efficiency, %; C i The inlet instrument displays the carbon dioxide concentration, ppm; C o The outlet instrument displays the carbon dioxide concentration in ppm. When the calculated carbon dioxide removal efficiency is lower than the removal efficiency setting value of the calcium-based absorbent, the calcium-based absorbent can be replaced.

[0072] In this embodiment, the reactor 1 further has a waste residue discharge end 17 , and the waste residue discharge end 17 is connected to a waste residue discharge pipeline assembly 500 . Specifically, the waste residue discharge pipeline assembly 500 includes a waste residue discharge pipe 501 and a residue discharge valve 502 .

[0073] In this embodiment, the return ash pipeline assembly 200 includes a return ash pipe 201 and a return ash fan 202 .

[0074] In this embodiment, the first input end 41 is connected to a calcium-based absorbent supply device through a calcium-based absorbent supply pipeline assembly 600 . The calcium-based absorbent supply pipeline assembly 600 includes a calcium-based absorbent supply pipe 601 and a calcium-based absorbent feeding valve 602 .

[0075] Based on the above carbon dioxide search and capture system, the working principle / process of the above system is as follows:

[0076] See also Figures 2 to 4 ,For the convenience of description, the “solid line pipeline” in the figure represents the running state, and the “dotted line pipeline” represents the shutdown state.

[0077] 1. Initial stage

[0078] All valves of the system (collecting gas valve 104, circulating gas valve 402, slag discharge valve 502, raw flue gas valve 22, carbon dioxide collection control valve 322, clean flue gas valve 324, calcium-based absorbent feeding valve 602) are in a closed state.

[0079] (II) Start-up phase

[0080] See also Figure 2 , turn on the dust collector 31 and the external heat source conveying device connected to the heat input end 15 to heat the reactor 1. When the reactor 1 reaches a certain temperature, turn on the compressor 102, the return ash fan 202, the original flue gas valve 22, the collection gas valve 104, and the clean flue gas valve 324 to ensure the balanced flow of gas in the system. At this time, the gas output pipeline assembly 100 and the return ash pipeline assembly 200 are in a conducting state.

[0081] See also Figure 3 When the output gas pressure of the compressor 102 reaches the preset pressure, the circulating gas valve 402 is opened, so that the gas with the preset pressure can be delivered to the ejector 4, so that the gas with the preset pressure can deliver the calcium-based absorbent delivered to the ejector 4 to the high-temperature heat exchanger 5 for heat exchange, and the preheated gas and calcium-based absorbent are then delivered to the reactor 1.

[0082] (III) Reactor 1 is in the carbonation reaction state

[0083] See also Figure 3, the reactor 1 is heated and maintained at a first preset temperature (generally about 650°C), and the flue gas input into the reactor 1 through the flue gas input part 2 reacts with the calcium-based absorbent to undergo a carbonation reaction. After the unreacted flue gas is pressurized by the compressor 102 of the gas output pipeline assembly 100, a portion is transported to the ejector 4, and the calcium-based absorbent transported to the ejector 4 is further transported to the high-temperature heat exchanger 5 for heat exchange, and the preheated gas and calcium-based absorbent are then transported to the reactor 1. The other portion is transported to the dust collector 31 for dust removal and then transported to the gas recovery and processing assembly 32, and is discharged through the clean flue gas discharge pipe 323 of the gas recovery and processing assembly 32 (the clean flue gas valve 324 is open, and the carbon dioxide collection control valve 322 is closed). At the same time, the return ash output from the dust collector 31 is transported to the reactor 1 through the return ash pipeline assembly as a raw material for the calcination reaction or carbonation reaction of the reactor 1.

[0084] (IV) Reactor 1 is switched from the carbonation reaction state to the calcination reaction state

[0085] In one of the examples, after the carbonation reaction continues for a preset reaction time (which can be set according to actual conditions, such as according to the content of high-purity carbon dioxide to be collected), the supply of raw flue gas to the reactor 1 is stopped (the specific operation is to close the raw flue gas valve 22), and the carbon dioxide concentration of the discharged clean flue gas is analyzed in real time by the clean flue gas analyzer 325 to determine whether the carbon dioxide concentration of the output gas (clean flue gas) of the gas recovery unit 3 is not greater than the standard switching concentration. If so, the reactor 1 is switched to the calcination reaction state stage, if not, the carbon dioxide absorption state is maintained.

[0086] In another example, after the carbonation reaction continues for a preset reaction time, the calcium-based absorbent is stopped from being delivered to the reactor 1 (specifically, the calcium-based absorbent feeding valve 602 is operated), and the state is directly switched. Of course, after the carbonation reaction continues for a preset reaction time, the calcium-based absorbent and flue gas are directly stopped from being delivered to the reactor 1 (specifically, the original flue gas valve 22 and the calcium-based absorbent feeding valve 602 are closed simultaneously).

[0087] (V) Reactor 1 is in the calcination reaction state

[0088] See also Figure 4 The reactor 1 is heated and maintained at a second preset temperature (generally about 950° C.), and carbon dioxide is generated by calcining the product of the carbonation reaction in the reactor 1. At the same time, the original flue gas valve 22, the circulating gas valve 402, and the calcium-based absorbent feed valve 602 are closed.

[0089] During the calcination reaction, the carbon dioxide concentration of the discharged clean flue gas is analyzed in real time by the clean flue gas analyzer 325. When the carbon dioxide concentration in the clean flue gas reaches the preset collection concentration, the clean flue gas valve 324 is closed and the carbon dioxide collection control valve 322 is opened to collect high-concentration carbon dioxide. At the same time, the return ash output by the dust collector 31 is transported to the reactor 1 through the return ash pipeline assembly as a raw material for the calcination reaction or carbonation reaction of the reactor 1.

[0090] In addition, it is worth noting that when the calculated carbon dioxide removal efficiency is lower than the removal efficiency setting value of the calcium-based absorbent, the slag discharge valve 502 can be opened to replace the calcium-based absorbent, which is not shown in the figure.

[0091] In addition, it is worth noting that when the reactor 1 is in the carbonation reaction state, the dust collector 31 can maintain the environmental protection emission requirements of the discharged clean flue gas, and the return ash collected by the dust collector 31 is heat-exchanged by the low-temperature heat exchanger 6 to form high-temperature return ash, and enters the reactor 1 to participate in the carbonation reaction. Correspondingly, when the reactor 1 is in the calcination reaction state, the high-temperature return ash formed by the dust collector 31 enters the reactor 1 to participate in the calcination reaction.

[0092] Based on the above carbon dioxide capture system, this embodiment further provides a carbon dioxide capture method, which specifically includes the following steps:

[0093] System startup preparation, including conveying raw flue gas to reactor 1;

[0094] The gas output from the reactor 1 is pressurized to a preset pressure and delivered to the ejector 4, so as to deliver the calcium-based absorbent delivered to the ejector 4 to the reactor 1;

[0095] The return ash outputted from the gas recovery unit 3 is transported to the reactor 1;

[0096] Controlling the reactor 1 to be in a carbonation reaction state;

[0097] The operating state of the reactor 1 is controlled to switch from the carbonation reaction state to the calcination reaction state. When the carbon dioxide concentration in the clean flue gas discharged from the gas recovery unit 3 after calcination reaches a preset collection concentration, the gas output from the reactor 1 is collected.

[0098] Specifically, the system startup preparation steps include:

[0099] When the reactor 1 is heated to a preset temperature, the original flue gas valve 22, the collection gas valve 104, and the clean flue gas valve 324 are opened to allow the flue gas of the entire system to flow in a balanced manner for a preset time;

[0100] When the pressure of the gas output by the compressor 102 reaches a preset pressure, the circulating gas valve 402 is opened.

[0101] Specifically, controlling the operating state of the reactor 1 to switch from the carbonation reaction state to the calcination reaction state specifically includes the following steps:

[0102] After the carbonation reaction continues for a preset reaction time, the supply of the original flue gas to the reactor 1 is stopped;

[0103] When judging whether the carbon dioxide concentration of the gas output from the gas recovery unit 3 is not greater than the standard switching concentration, if so, the state is switched, and if not, the carbon dioxide absorption state is maintained.

[0104] It can be known that, through this scheme, the flue gas delivered to the reactor 1 can react as completely as possible, thereby reducing the carbon dioxide concentration of the gas output from the gas recovery unit 3, and reducing carbon emissions to a certain extent. Of course, in other embodiments, it is also possible to directly stop delivering the calcium-based absorbent to the reactor 1 after the carbonation reaction continues for a preset reaction time, and directly switch the state to reduce the loss of the calcium-based absorbent. It is also possible to directly stop delivering the calcium-based absorbent and flue gas to the reactor 1 after the carbonation reaction continues for a preset reaction time.

[0105] Furthermore, the method also includes the following steps: using a high-temperature heat exchanger 5 to perform heat exchange between the calcium-based absorbent and the gas output from the reactor 1; using a low-temperature heat exchanger 6 to perform heat exchange between the return ash output from the dust collector 31 and the gas output from the compressor 102.

[0106] Furthermore, the method further comprises the following steps:

[0107] Calculate the carbon dioxide removal efficiency based on the carbon dioxide concentration in the original flue gas and the carbon dioxide concentration in the clean flue gas discharged from the gas recovery unit 3;

[0108] Determine whether the carbon dioxide removal efficiency is lower than the removal efficiency set value. If so, replace the calcium-based absorbent in the reactor.

[0109] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A carbon dioxide capture system, characterized in that: include: The reactor (1) has a flue gas input end (11), a gaseous material output end (12), a return ash input end (13), a calcium-based absorbent input end (14), a heat input end (15) for connecting to an external heat source transport device, and a thermometer mounting end (16) for inserting a thermometer; A smoke input part (2) connected to the smoke input end (11); The gas recovery section (3) comprises a dust collector (31) and a gas recovery processing assembly (32); the gas output end of the dust collector (31) is connected to the gas recovery processing assembly (32), the gas input end of the dust collector (31) is connected to the gaseous material output end (12) via a gas output pipeline assembly (100), and the return ash output end of the dust collector (31) is connected to the return ash input end (13) via a return ash pipeline assembly (200); An ejector (4) comprises an output end (40), a first input end (41) and a second input end (42); the output end (40) is connected to the calcium-based absorbent input end (14) via a calcium-based absorbent delivery pipeline assembly (300); the first input end (41) is used to be connected to a calcium-based absorbent supply device, and the second input end (42) is connected to the gas output pipeline assembly (100) via a branch pipeline assembly (400) and delivers gas of a preset pressure to the ejector (4) so ​​as to deliver the calcium-based absorbent to the reactor (1).

2. A carbon dioxide capture system according to claim 1, characterized in that: The gas output pipeline assembly (100) comprises a first pipe (101), a compressor (102), a second pipe (103) and a gas collecting valve (104); The gaseous material output end (12), the first pipe (101), the compressor (102), the second pipe (103) and the gas input end of the dust collector (31) are connected in sequence, and the gas collection valve (104) is arranged on the second pipe (103); The shunt pipe assembly (400) comprises a shunt pipe (401) and a circulating gas valve (402) arranged on the shunt pipe (401); one end of the shunt pipe (401) is connected to the output end of the compressor (102), and the other end is connected to the second input end (42).

3. A carbon dioxide capture system according to claim 2, characterized in that: It also includes a high-temperature heat exchanger (5), wherein the high-temperature heat exchanger (5) is located upstream of the compressor (102); and / or, It also includes a low-temperature heat exchanger (6), which is located upstream of the dust collector (31) and downstream of the circulating gas valve (402).

4. A carbon dioxide capture system according to any one of claims 1 to 3, characterized in that: Also includes: The high-temperature heat exchanger (5) comprises a first high-temperature heat exchange channel (51) and a second high-temperature heat exchange channel (52), wherein the first high-temperature heat exchange channel (51) is connected to a pipe section of the gas output pipeline assembly (100) close to the gaseous material output end (12), and the second high-temperature heat exchange channel (52) is connected to the calcium-based absorbent transport pipeline assembly (300); and / or, The low-temperature heat exchanger (6) comprises a first low-temperature heat exchange channel (61) and a second low-temperature heat exchange channel (62), wherein the first low-temperature heat exchange channel (61) is connected to a pipe section of the gas output pipeline assembly (100) away from the gaseous material output end (12), and the second low-temperature heat exchange channel (62) is connected to the return ash pipeline assembly (200).

5. A carbon dioxide capture system according to claim 1, characterized in that: The smoke input part (2) comprises an original smoke pipe (21), an original smoke valve (22) and an original smoke analyzer (23); The original smoke pipe (21) is connected to the smoke input end (11), and the original smoke valve (22) and the original smoke analyzer (23) are both installed on the original smoke pipe (21); The gas recovery and processing component (32) comprises a carbon dioxide collection pipe (321), a carbon dioxide collection control valve (322), a clean flue gas discharge pipe (323), a clean flue gas valve (324) and a clean flue gas analyzer (325); The carbon dioxide collection control valve (322) is installed on the carbon dioxide collection pipe (321), and the clean smoke valve (324) is installed on the clean smoke exhaust pipe (323); The clean flue gas analyzer (325) is installed upstream of the carbon dioxide collection control valve (322) and the clean flue gas valve (324).

6. A carbon dioxide capture method based on a carbon dioxide capture system according to any one of claims 1 to 5, characterized in that: The following steps are involved: System startup preparation, including conveying raw flue gas into the reactor (1); The gas output from the reactor (1) is pressurized to a preset pressure and delivered to the ejector (4), so as to deliver the calcium-based absorbent delivered to the ejector (4) to the reactor (1); transporting the return ash output from the gas recovery unit (3) to the reactor (1); Controlling the reactor (1) to be in a carbonation reaction state; The operating state of the reactor (1) is controlled to switch from the carbonation reaction state to the calcination reaction state, and when the carbon dioxide concentration in the clean flue gas discharged from the gas recovery part (3) after calcination reaches a preset collection concentration, the gas output from the reactor (1) is collected.

7. The carbon dioxide capture method according to claim 6, characterized in that: The method further comprises the following steps: using a high-temperature heat exchanger (5) to perform heat exchange between the calcium-based absorbent and the gas output from the reactor (1); and / or using a low-temperature heat exchanger (6) to perform heat exchange between the return ash output from the dust collector (31) and the gas output from the compressor (102).

8. The carbon dioxide capture method according to claim 6, characterized in that: The system startup preparation steps include: When the reactor (1) is heated to a preset temperature, the original smoke valve (22), the collection gas valve (104), and the clean smoke valve (324) are opened to allow the smoke of the entire system to flow in a balanced manner for a preset time; When the pressure of the gas output by the compressor (102) reaches a preset pressure, the circulating gas valve (402) is opened.

9. The carbon dioxide capture method according to claim 6, characterized in that: The control of the operating state of the reactor (1) is switched from the carbonation reaction state to the calcination reaction state, specifically comprising the following steps: After the carbonation reaction continues for a preset reaction time, the supply of the original flue gas to the reactor (1) is stopped, and it is determined whether the carbon dioxide concentration of the gas output from the gas recovery unit (3) is not greater than the standard switching concentration. If so, the state is switched; if not, the carbon dioxide absorption state is maintained; or, After the carbonation reaction continues for a preset reaction time, the supply of the calcium-based absorbent to the reactor (1) is stopped, and the state is directly switched.

10. The carbon dioxide capture method according to claim 6, characterized in that: The following steps are also included: Calculate the carbon dioxide removal efficiency based on the carbon dioxide concentration in the original flue gas and the carbon dioxide concentration in the clean flue gas discharged from the gas recovery unit (3); Determine whether the carbon dioxide removal efficiency is lower than the removal efficiency set value. If so, replace the calcium-based absorbent in the reactor.

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