Fixed-bed flue gas purification system and control method therefor

Abstract

A fixed-bed flue gas purification system and a control method therefor. The fixed-bed flue gas purification system comprises a heat exchange medium supply device and a plurality of purification devices, wherein each purification device comprises a shell, an adsorbent layer arranged inside the shell, and a heat exchanger arranged inside the shell and used for exchanging heat with the adsorbent layer. The purification device has a plurality of running modes, and the temperature of a heat exchange medium supplied to the purification device by the heat exchange medium supply device corresponds to the running mode of the purification device. The plurality of running modes include an adsorption mode, and in the adsorption mode, the heat exchange medium supply device continuously supplies the heat exchange medium having a temperature of -20°C to -10°C to the heat exchanger to cool the flue gas and the adsorbent layer during adsorption purification.

Description

Fixed bed flue gas purification system and control method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 2023114286304 and application date October 30, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present disclosure relates to the technical field of flue gas adsorption purification, and in particular to a fixed-bed flue gas purification system and a control method thereof. Background Art

[0004] Coal-fired power plant flue gas desulfurization and denitrification primarily utilize SCR denitrification and FGD desulfurization technologies. However, SCR denitrification can lead to problems such as ammonia escape and hazardous solid catalyst waste. FGD desulfurization uses limestone as a raw material, and the mining of large quantities of limestone can cause serious environmental damage to the mountain. Furthermore, the gypsum produced after desulfurization has become a difficult-to-dispose waste and cannot be effectively treated. Furthermore, the removal efficiency of other pollutants such as heavy metals, VOCs, and halides is low.

[0005] In the related art, activated coke desulfurization technology is used to treat sintering flue gas. However, the adsorption efficiency in the activated coke desulfurization process is low, and the amount of adsorbent used is large, resulting in a large adsorption tower. In addition, the adsorption is carried out at a high temperature of approximately 200°C.

[0006] Summary of the Invention

[0007] The present disclosure is based on the inventors' findings and understanding of the following facts and problems:

[0008] In related technologies, activated coke desulfurization processes operate at relatively high temperatures, typically around 100°C. This results in low adsorption capacity for the adsorbent, resulting in large adsorbent usage and bulky adsorption towers, poor adsorption purification results, and the inability to achieve near-zero emissions. Furthermore, the adsorption and removal process releases significant heat, further impacting the adsorbent's efficiency.

[0009] To this end, the present disclosure proposes a fixed-bed flue gas purification system, which can continuously purify flue gas and has the characteristics of high purification efficiency, small size, high safety, low energy consumption, and can achieve near-zero emissions.

[0010] The fixed bed flue gas purification system disclosed in the present invention includes: a heat exchange medium supply device and multiple purification devices, the purification device includes a shell, an adsorbent layer arranged in the shell and a heat exchanger arranged in the shell for exchanging heat with the adsorbent layer, the heat exchange medium supply device is used to supply heat exchange medium to the heat exchanger of the purification device, the purification device has multiple operating modes, the temperature of the heat exchange medium supplied by the heat exchange medium supply device to any purification device corresponds to the operating mode of the purification device, and the multiple operating modes include an adsorption mode, in which the heat exchange medium supply device continuously supplies heat exchange medium in a sub-zero temperature zone to the heat exchanger to cool the adsorbent layer in the shell and the flue gas passed into the shell, so that the adsorbent layer performs low-temperature adsorption purification on the flue gas in the sub-zero temperature zone, and the multiple purification devices are connected in parallel with each other, and within a predetermined time period, at least one of the purification devices operates in the adsorption mode.

[0011] In the fixed-bed flue gas purification system disclosed herein, when the purification device operates in adsorption mode, a heat exchange medium supply device introduces low-temperature air into the heat exchanger to simultaneously cool the flue gas and the adsorbent layer, maintaining the flue gas and adsorbent layer in a sub-zero temperature range. Pollutants in the flue gas are adsorbed in this sub-zero temperature range, increasing the adsorption capacity of the adsorbent. This reduces the amount of adsorbent loaded within the purification device, minimizing the size of the purification device and lowering initial construction costs. Furthermore, the continuous introduction of heat exchange medium promptly removes the heat released during the flue gas adsorption purification process, preventing the adsorbent layer from heating up and causing a decrease in adsorption efficiency.

[0012] In the fixed-bed flue gas purification system disclosed herein, at least one of the multiple purification devices always operates in adsorption mode, thereby ensuring the continuity of the flue gas purification process and improving the flue gas purification efficiency.

[0013] In some embodiments, a first support member and a second support member are provided in the shell, and the first support member and the second support member isolate the inner cavity of the shell into an air intake chamber, an adsorption chamber and an exhaust chamber arranged in sequence along the vertical direction. The adsorbent layer is provided in the adsorption chamber, the air intake chamber is connected to the flue gas inlet of the shell, and the exhaust chamber is connected to the flue gas outlet of the shell; the heat exchanger is a heat exchange tube provided in the adsorption chamber, and the heat exchange tube is serpentine, spiral or vortex-shaped.

[0014] In some embodiments, there is one heat exchange medium supply device, which is used to supply heat exchange medium of different temperatures to multiple purification devices, or there are multiple heat exchange medium supply devices and they correspond one-to-one to multiple purification devices.

[0015] In some embodiments, the plurality of operating modes further include a pre-cooling mode and a regeneration mode, the plurality of purification devices include a first purification device, a second purification device, and a third purification device, and the heat exchange medium supply device includes a first heat exchange medium supply device, a second heat exchange medium supply device, and a third heat exchange medium supply device, wherein:

[0016] The first heat exchange medium supply device is used to supply a heat exchange medium at a first temperature, a heat exchange medium at a second temperature, or a heat exchange medium at a third temperature to the first purification device, so that the first purification device operates in a precooling mode, an adsorption mode, or a regeneration mode;

[0017] The second heat exchange medium supply device is used to supply a heat exchange medium at a first temperature, a heat exchange medium at a second temperature, or a heat exchange medium at a third temperature to the second purification device so that the second purification device operates in a precooling mode, an adsorption mode, or a regeneration mode;

[0018] The third heat exchange medium supply device is used to supply the heat exchange medium at the first temperature, the heat exchange medium at the second temperature, or the heat exchange medium at the third temperature to the third purification device, so that the third purification device operates in the pre-cooling mode, the adsorption mode, or the regeneration mode.

[0019] The first temperature is 10°C to 30°C, the second temperature is -20°C to -10°C, and the third temperature is 200°C to 400°C.

[0020] In the fixed-bed flue gas purification system disclosed herein, when the purification device operates in regeneration mode, hot air is introduced into the heat exchanger to indirectly exchange heat with the adsorbent, thereby avoiding direct heating of the adsorbent that would cause combustion due to excessive temperature, thereby improving the safety of the device.

[0021] In the fixed-bed flue gas purification system disclosed herein, when the purification device operates in pre-cooling mode, ambient temperature air is introduced into the heat exchanger to pre-cool the regenerated adsorbent before proceeding to the subsequent adsorption mode. Compared to directly entering the adsorption mode after the regeneration mode, the addition of the pre-cooling mode between the two modes reduces the overall energy consumption of the purification device during the flue gas purification process.

[0022] In some embodiments, the first to third heat exchange medium supply devices also include a four-way valve, the four-way valve having a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port is connected to a first medium source for providing a heat exchange medium at a first temperature, the second valve port is connected to a second medium source for providing a heat exchange medium at a second temperature, the third valve port is connected to a third medium source for providing a heat exchange medium at a third temperature, and the fourth valve port is connected to the heat exchanger, the first medium source is room temperature air, the second medium source is low-temperature air cooled by a refrigerator, and the third medium source is hot air heated by a heater.

[0023] In some embodiments, the fixed-bed flue gas purification system further includes a regeneration gas treatment device, which is connected to the purification device and is used to treat the regeneration gas discharged from the purification device.

[0024] The present disclosure also provides a control method for a fixed-bed flue gas purification system.

[0025] According to the control method of the fixed-bed flue gas purification system disclosed herein, the fixed-bed flue gas purification system includes a plurality of purification devices, each of which includes a housing, an adsorbent layer disposed within the housing, and a heat exchanger disposed within the housing for exchanging heat with the adsorption layer. The purification device has a plurality of operating modes, including an adsorption mode. The control method includes:

[0026] Determine the operating mode of each purification unit;

[0027] supplying a heat exchange medium to a heat exchanger of each purification device according to the operation mode of the purification device, wherein the temperature of the heat exchange medium corresponds to the operation mode of the purification device;

[0028] During a predetermined time period, at least one of the purification devices operates in the adsorption mode. When any purification device is in the adsorption mode, a sub-zero temperature zone heat exchange medium is supplied to the heat exchanger of the purification device to cool the adsorbent layer in the shell and the flue gas entering the shell, so that the adsorbent layer performs low-temperature adsorption purification on the flue gas in the sub-zero temperature zone.

[0029] In some embodiments, the plurality of operating modes further include a pre-cooling mode and a regeneration mode, and the plurality of purification devices include a first purification device, a second purification device, and a third purification device, wherein:

[0030] When the first purification device operates in the pre-cooling mode, the second purification device operates in the adsorption mode and the third purification device operates in the regeneration mode;

[0031] When the first purification device operates in the adsorption mode, the second purification device operates in the regeneration mode, and the third purification device operates in the pre-cooling mode;

[0032] When the first purification device operates in the regeneration mode, the second purification device operates in the pre-cooling mode, and the third purification device operates in the adsorption mode.

[0033] In some embodiments, the first purification device is operated in the pre-cooling mode, the adsorption mode and the regeneration mode in sequence, while the second purification device is operated in the adsorption mode, the regeneration mode and the pre-cooling mode in sequence, and the third purification device is operated in the regeneration mode, the pre-cooling mode and the adsorption mode in sequence.

[0034] In some embodiments, when any one of the first to third purification devices operates in the pre-cooling mode, the adsorption mode, and the regeneration mode, a heat exchange medium at a first temperature, a heat exchange medium at a second temperature, and a heat exchange medium at a third temperature are respectively introduced into the heat exchanger of any one of the purification devices. The heat exchange medium at the first temperature is normal temperature air of 10°C to 30°C, the heat exchange medium at the second temperature is low-temperature air of -20°C to -10°C cooled by a refrigerator, and the heat exchange medium at the third temperature is hot air of 200°C to 400°C heated by a heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a schematic diagram of a fixed bed flue gas purification system according to an embodiment of the present disclosure.

[0036] FIG2 is a schematic diagram of a purification device and a heat exchange medium supply device of a fixed bed flue gas purification system according to an embodiment of the present disclosure.

[0037] FIG3 is a schematic diagram of an adsorption unit of a fixed bed flue gas purification system according to an embodiment of the present disclosure.

[0038] Reference numerals:

[0039] Purification device 1, first purification device 1A, second purification device 1B, second purification device 1C,

[0040] Shell 11, adsorbent layer 12, adsorption unit 121, breathable shell 1211, adsorbent particles 1212, heat exchanger 13, heat exchange tube 131, first support member 14, second support member 15, flue gas inlet 101, flue gas outlet 102,

[0041] Heat exchange medium supply device 2, first heat exchange medium supply device 2A, second heat exchange medium supply device 2B, third heat exchange medium supply device 2C,

[0042] Air pump 21, refrigerator 22, heater 23, four-way valve 24,

[0043] Regeneration gas treatment device 3, boiler 4, chimney 5. DETAILED DESCRIPTION

[0044] The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0045] The fixed bed flue gas purification system according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0046] As shown in FIG. 1 and FIG. 2 , the fixed bed flue gas purification system according to the embodiment of the present disclosure includes: a heat exchange medium supply device 2 and a plurality of purification devices 1 .

[0047] The purification device 1 includes a housing 11, an adsorbent layer 12, and a heat exchanger 13. The adsorbent layer 12 is disposed within the housing 11 and is used to purify the flue gas entering the housing 11 by low-temperature adsorption. The heat exchanger 13 is disposed within the housing 11 and is used to indirectly exchange heat with the adsorbent layer 12.

[0048] In the embodiment of the present disclosure, the adsorbent layer 12 is formed by stacking adsorbents, and the adsorbents can be filled in a breathable shell 1211 to form an adsorption unit 121. That is, as shown in FIG3 , the adsorption unit 121 includes a breathable shell 1211 and an adsorbent filled in the breathable shell 1211. The adsorbent can be a granular or powdered adsorbent, or an adsorbent body made of a powdered or granular adsorbent, such as a spherical body or a cylindrical body formed by a powdered or granular adsorbent with a binder. Of course, a protective shell can be further formed outside the adsorbent body, such as a breathable membrane covering the outside of the adsorbent body, to further improve the strength of the adsorbent body.

[0049] In some embodiments, the breathable housing 1211 has air holes through which smoke can enter the breathable housing 1211. The smoke can then pass through the gaps between adjacent adsorbents and / or the pores within the adsorbents themselves, thereby reducing direct collisions, friction, and wear between adsorbents, as well as the generation of dust. The breathable housing 1211 can be in the shape of a spherical, cylindrical, or other rotating body. In some embodiments, the adsorption unit 121 has a diameter of 10 mm to 100 mm, and the adsorbent particles 1212 have a diameter of 1 mm to 10 mm.

[0050] By placing the adsorbent in the breathable shell 1211 to form the adsorption unit 121, on the one hand, the dust generated by the collision between the adsorbents can be reduced; on the other hand, it is beneficial to increase the contact area between the flue gas and the adsorbent and improve the air permeability of the adsorbent, which is particularly beneficial for low-temperature adsorption.

[0051] The heat exchange medium supply device 2 is connected to the purification device 1 and is used to supply heat exchange medium to the heat exchanger 13 of the purification device 1. The purification device 1 has multiple operating modes, and the temperature of the heat exchange medium supplied by the heat exchange medium supply device 2 to the purification device 1 corresponds to the operating mode of the purification device 1.

[0052] In some embodiments, the multiple operating modes include an adsorption mode. When the purification device 1 operates in the adsorption mode, the heat exchange medium supply device 2 continuously supplies a sub-zero temperature heat exchange medium to the heat exchanger 13 of the purification device 1 to cool the adsorbent layer 12 within the housing 11 and the flue gas entering the housing 11, so that the adsorbent layer 12 performs low-temperature adsorption purification on the flue gas in the sub-zero temperature range.

[0053] It can be understood that the flue gas to be purified is transported from the boiler 4 (for example, in a power plant or steel plant) into the purification device 1, and at the same time, the heat exchange medium supply device 2 continuously transports the heat exchange medium of the temperature corresponding to the adsorption mode to the heat exchanger 13 of the purification device 1, so as to cool the flue gas and the adsorbent layer 12 to the sub-zero temperature zone and keep it in the sub-zero temperature zone at all times.

[0054] It should be understood that the inventors discovered through research that in the low-temperature environment of the sub-zero temperature zone, nitrogen oxides in the flue gas undergo low-temperature oxidation and adsorption on the surface of adsorbents such as activated carbon, oxidizing the difficult-to-adsorb nitric oxide gas into easily adsorbed nitrogen dioxide gas, achieving a hundreds-fold increase in adsorption capacity. In addition, the adsorption capacity of components such as sulfur dioxide, carbon dioxide and heavy metals also increases exponentially in low-temperature environments.

[0055] In some embodiments, the temperature of the low temperature environment is, for example, -80°C to -5°C.

[0056] In some embodiments, the low-temperature environment is between -20°C and -10°C. The inventors have discovered through research that the lower the flue gas temperature, the more beneficial it is for adsorption purification. However, too low a flue gas temperature complicates the structure of the flue gas cooling equipment and increases energy consumption. For example, it requires the purification device 1 and pipelines to be equipped with an insulation layer, requiring high sealing performance, which increases costs. Furthermore, excessively low temperatures can easily lead to condensation within the purification device 1, causing the adsorbent to stick and clog, affecting adsorption. Therefore, it is beneficial to cool the flue gas and adsorbent layer 12 to a temperature between -20°C and -10°C.

[0057] As a result, pollutants in the flue gas are adsorbed in the sub-zero temperature range, increasing the adsorption capacity of the adsorbent, thereby reducing the amount of adsorbent required within the purification device 1, reducing the volume of the purification device 1 and lowering the initial construction cost. Furthermore, the continuous flow of heat exchange medium promptly removes the heat released during the flue gas adsorption process, preventing the temperature of the adsorbent layer 12 from rising, which could lead to a decrease in the adsorption efficiency of the adsorbent.

[0058] In addition, there is always at least one purification device 1 among the multiple purification devices 1 running in adsorption mode to ensure that the fixed bed flue gas purification system of the embodiment of the present disclosure can continuously pass the flue gas to be purified, continuously carry out the flue gas purification process, and improve the flue gas purification efficiency.

[0059] In some embodiments, as shown in FIG2 , a first support member 14 and a second support member 15 are provided within the housing 11. The first support member 14 and the second support member 15 separate the interior of the housing 11 into an air intake chamber, an adsorption chamber, and an exhaust chamber. The adsorbent layer 12 is disposed within the adsorption chamber. The air intake chamber communicates with the flue gas inlet 101 of the housing 11, and the exhaust chamber communicates with the flue gas outlet 102 of the housing 11.

[0060] It can be understood that when the purification device 1 operates in adsorption mode, the flue gas to be purified enters the air inlet chamber through the flue gas inlet 101 of the shell 11, flows from the air inlet chamber to the adsorption chamber, and is adsorbed and purified in the adsorbent layer 12. The clean flue gas generated by purification flows from the adsorption chamber to the exhaust chamber and is discharged from the flue gas outlet 102 to the chimney 5.

[0061] In some embodiments, the shell 11 is arranged horizontally, and the first support member 14 and the second support member 15 are arranged vertically in the shell 11 to separate the inner cavity of the shell 11 horizontally into an air intake chamber, an adsorption chamber and an exhaust chamber that are connected in sequence. The smoke inlet 101 of the shell 11 is connected to the air intake chamber, and the smoke outlet 102 of the shell 11 is connected to the exhaust chamber.

[0062] In other embodiments, the shell 11 is vertically arranged, and the first support member 14 and the second support member 15 are arranged horizontally in the shell 11 to separate the inner cavity of the shell 11 into an air intake chamber, an adsorption chamber and an exhaust chamber that are connected in sequence along the vertical direction. The smoke inlet 101 of the shell 11 is connected to the air intake chamber, and the smoke outlet 102 of the shell 11 is connected to the exhaust chamber.

[0063] Specifically, as shown in Figure 2, the housing 11 is a vertical oblong container. Both the first support member 14 and the second support member 15 are partitions. The first support member 14 and the second support member 15 are arranged horizontally and in close contact with the inner wall of the housing 11. The first support member 14 and the second support member 15 are spaced apart vertically. The chamber defined between the first support member 14 and the second support member 15 is the adsorption chamber. Below the first support member 14 is the air intake chamber, and above the second support member 15 is the exhaust chamber. A smoke inlet 101 is located at the bottom of the housing 11 and communicates with the air intake chamber. A smoke outlet 102 is located at the top of the housing 11 and communicates with the exhaust chamber.

[0064] Furthermore, a plurality of smoke holes are respectively formed on the first support member 14 and the second support member 15 . The size of the smoke holes is smaller than the size of the adsorbent particles in the adsorption space to prevent the adsorbent from falling.

[0065] In some embodiments, heat exchanger 13 is a heat exchange tube 131 disposed within the adsorption chamber. Heat exchange tube 131 has a serpentine, spiral, or vortex shape. The inlet of heat exchange tube 131 communicates with the heat exchange medium outlet of heat exchange medium supply device 2, and the outlet of heat exchange tube 131 communicates with the heat exchange medium inlet of heat exchange medium supply device 2, thereby forming a heat exchange medium circulation loop.

[0066] In some embodiments, as shown in FIG2 , heat exchange tubes 131 are embedded within the adsorbent layer 12 and spirally ascend. One inlet end of the heat exchange tubes 131 penetrates the wall of the shell 11, such that the inlet of the heat exchange tubes 131 is located outside the shell 11. One outlet end of the heat exchange tubes 131 penetrates the wall of the shell 11, such that the outlet of the heat exchange tubes 131 is located outside the shell 11. Furthermore, the inlet of the heat exchange tubes 131 is adjacent to the bottom of the shell 11, and the outlet of the heat exchange tubes 131 is adjacent to the top of the shell 11.

[0067] In some embodiments, there is one heat exchange medium supply device 2, which is used to supply heat exchange medium of different temperatures to multiple purification devices 1. Alternatively, there are multiple heat exchange medium supply devices 2 and they correspond one to one with multiple purification devices 1.

[0068] In other words, the heat exchange medium outlet of the heat exchange medium supply device 2 is connected to the inlets of the heat exchangers 13 of the multiple purification devices 1 through multiple pipelines, and the outlets of the heat exchangers 13 of the multiple purification devices 1 are respectively connected to the heat exchange medium inlet of the heat exchange medium supply device 2 through pipelines. Alternatively, the heat exchange medium outlet of the heat exchange medium supply device 2 is connected to the inlets of the heat exchangers 13 of the corresponding purification devices 1 through pipelines, and the heat exchange medium inlet of the heat exchange medium supply device 2 is connected to the outlet of the heat exchanger 13 of the corresponding purification device 1 through pipelines.

[0069] In some embodiments, as shown in FIG1 , multiple purification devices 1 are connected in parallel, and any purification device 1 sequentially operates in multiple operating modes, and the operating modes of the multiple purification devices 1 are different from each other.

[0070] In some embodiments, the plurality of operating modes further include a pre-cooling mode and a regeneration mode. The plurality of purification devices 1 include a first purification device 1A, a second purification device 1B, and a third purification device 1C. The operating modes of the first purification device 1A, the second purification device 1B, and the third purification device 1C are different from each other, and any one of the first purification device 1A, the second purification device 1B, and the third purification device 1C operates in the pre-cooling mode, the adsorption mode, and the regeneration mode in sequence.

[0071] When the first purification device 1A is operating in the pre-cooling mode, the second purification device 1B is operating in the adsorption mode and the third purification device 1C is operating in the regeneration mode. When the first purification device 1A is operating in the adsorption mode, the second purification device 1B is operating in the regeneration mode and the third purification device 1C is operating in the pre-cooling mode. When the first purification device 1A is operating in the regeneration mode, the second purification device 1B is operating in the pre-cooling mode and the third purification device 1C is operating in the adsorption mode.

[0072] Therefore, the purification device 1 is a fixed bed adsorber, and the purification device 1 performs adsorption, regeneration and pre-cooling rotation operations in sequence, avoiding the problems of adsorbent movement wear, material blockage and poor air tightness caused by the moving bed adsorber.

[0073] It should be understood that in pre-cooling mode, the heat exchange medium supply device 2 supplies a heat exchange medium at a first temperature to the heat exchanger 13 of the purification device 1 to pre-cool the adsorbent layer 12. In adsorption mode, the heat exchange medium supply device 2 supplies a heat exchange medium at a second temperature to the heat exchanger 13 of the purification device 1 to cool the flue gas and the adsorbent layer 12 while purifying the flue gas through adsorption. In regeneration mode, the heat exchange medium supply device 2 supplies a heat exchange medium at a third temperature to the heat exchanger 13 of the purification device 1 to heat the adsorbent layer 12 to desorb and regenerate the adsorbent. The first temperature is greater than or equal to the second temperature, and the third temperature is greater than the first temperature.

[0074] During the flue gas purification process, purification device 1 operates in adsorption mode, purifying the incoming flue gas through adsorption. After the adsorbent is saturated with adsorption, purification device 1 operates in regeneration mode, desorbing and regenerating the saturated adsorbent. After the adsorbent is desorbed and regenerated, purification device 1 operates in precooling mode, precooling the adsorbent layer 121 heated during the regeneration process. This completes one cycle of operation of purification device 1.

[0075] When the purification device 1 operates in the regeneration mode, the flue gas is stopped from being introduced into the purification device 1, and the heat exchange medium of the third temperature is continuously supplied to the heat exchanger 13 of the purification device 1 through the heat exchange medium supply device 2 to indirectly heat the adsorbent layer 12 to the set temperature, so that the adsorbent is desorbed and regenerated, thereby avoiding the phenomenon of the adsorbent being burned due to excessive temperature during direct heating, thereby improving the safety of the purification device 1.

[0076] When the purification device 1 operates in the pre-cooling mode, after the desorption and regeneration of the adsorbent layer 12 is completed, the heat exchange medium of the first temperature is continuously supplied to the heat exchanger 13 of the purification device 1 through the heat exchange medium supply device 2 to perform preliminary indirect cooling of the adsorbent layer 12 and cool it to room temperature, so that the purification device 1 can subsequently operate in the adsorption mode.

[0077] It should be understood that compared to directly introducing a heat exchange medium at a second temperature after regeneration to operate in the adsorption mode, since the ambient temperature is higher than the temperature of the purification device 1 when operating in the adsorption mode, directly cooling the regenerated adsorbent layer 12 to the subzero temperature range with the heat exchange medium at the second temperature consumes more energy. Therefore, the adsorbent layer 12 is first pre-cooled to room temperature by introducing a heat exchange medium at the first temperature, and then cooled to the subzero temperature range with the heat exchange medium at the second temperature, thereby reducing overall energy consumption through a stepped cooling method.

[0078] For example, in regeneration mode, the temperature of the heat exchange medium supplied by the heat exchange medium supply device 2 to the heat exchanger 13 of the purifier 1 is 200°C to 400°C. In precooling mode, the temperature of the heat exchange medium supplied by the heat exchange medium supply device 2 to the heat exchanger 13 of the purifier 1 is 10°C to 30°C. In adsorption mode, the temperature of the heat exchange medium supplied by the heat exchange medium supply device 2 to the heat exchanger 13 of the purifier 1 is -20°C to -10°C. That is, the first temperature is 10°C to 30°C, the second temperature is -20°C to -10°C, and the third temperature is 200°C to 400°C.

[0079] In some embodiments, the heat exchange medium provided by the heat exchange medium supply device 2 is air, water or refrigerant.

[0080] For example, if the heat exchange medium is air. In adsorption mode, the heat exchange medium supply device 2 delivers low-temperature air of -20°C to -10°C to the heat exchanger 13 of the purification device 1. In regeneration mode, the heat exchange medium supply device 2 delivers hot air of 200°C to 400°C to the heat exchanger 13 of the purification device 1. In pre-cooling mode, the heat exchange medium supply device 2 delivers normal temperature air of 10°C to 30°C to the heat exchanger 13 of the purification device 1. Since the cost of air is relatively low, air can be directly captured from the atmosphere and is easily obtained. Therefore, the use of air as the heat exchange medium can improve the economy of the fixed bed flue gas purification system of the embodiment of the present disclosure.

[0081] In some embodiments, as shown in FIG2 , the heat exchange medium supply device 2 includes an air pump 21, a refrigerator 22, and a heater 23. The air pump 21, refrigerator 22, and heater 23 are respectively connected to the heat exchanger 13 of the purification device 1 to supply heat exchange medium of different temperatures to the heat exchanger 13 of the purification device 1.

[0082] In adsorption mode, air indirectly exchanges heat with the refrigerant in the refrigerator 22 to produce low-temperature air, which is then transported to the heat exchanger 13 of the purification device 1 to indirectly cool the flue gas and adsorbent layer 12 to a sub-zero temperature range. In regeneration mode, the heater 23 heats the air to generate hot air, which is then transported to the heat exchanger 13 of the purification device 1 to indirectly heat the adsorbent layer 12. In pre-cooling mode, the air pump 21 directly draws room-temperature air from the atmosphere and transports it to the heat exchanger 13 of the purification device 1 to pre-cool the regenerated adsorbent layer 12.

[0083] In some embodiments, as shown in FIG1 , there are multiple heat exchange medium supply devices 2 , and the multiple heat exchange medium supply devices 2 include a first heat exchange medium supply device 2A, a second heat exchange medium supply device 2B, and a third heat exchange medium supply device 2C.

[0084] The first heat exchange medium supply device 2A is used to supply the first purification device 1A with a heat exchange medium at a first temperature, a heat exchange medium at a second temperature, or a heat exchange medium at a third temperature, so that the first purification device 1A operates in a precooling mode, an adsorption mode, or a regeneration mode.

[0085] The second heat exchange medium supply device 2B is used to supply the heat exchange medium at the first temperature, the second temperature or the third temperature to the second purification device 1B, so that the second purification device 1B operates in the precooling mode, the adsorption mode or the regeneration mode.

[0086] The third heat exchange medium supply device 2C is used to supply the heat exchange medium at the first temperature, the second temperature or the third temperature to the third purification device 1C so that the third purification device 1C operates in the precooling mode, the adsorption mode or the regeneration mode.

[0087] In some embodiments, the first to third heat exchange medium supply devices 2C also include a four-way valve 24, the four-way valve 24 has a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port is connected to the first medium source (normal temperature air) for providing a heat exchange medium at a first temperature, the second valve port is connected to the second medium source (low-temperature air cooled by the refrigerator 22) for providing a heat exchange medium at a second temperature, the third valve port is connected to the third medium source (hot air heated by the heater 23) for providing a heat exchange medium at a third temperature, and the fourth valve port is connected to the heat exchanger 13 of the purification device 1.

[0088] It can be understood that by setting a four-way valve 24 between the air pump 21, the refrigerator 22, the heater 23 and the heat exchanger 13 of the purification device 1, heat exchange media of different temperatures can enter the heat exchanger 13 through one inlet, thereby reducing the number of inlets of the heat exchanger 13, reducing the layout of the pipelines, and reducing costs.

[0089] Specifically, the outlet of the air pump 21 is connected to the first valve port of the four-way valve 24 via a pipeline, the heat exchange medium outlet of the refrigerator 22 is connected to the second valve port of the four-way valve 24 via a pipeline, the heat exchange medium outlet of the heater 23 is connected to the third valve port of the four-way valve 24 via a pipeline, and the fourth valve port of the four-way valve 24 is connected to the inlet of the heat exchanger 13.

[0090] Furthermore, the outlet of the heat exchanger 13 is connected to the inlet of the air pump 21, the heat exchange medium inlet of the refrigerator 22, and the heat exchange medium inlet of the heater 23 via pipelines. Similarly, a four-way valve 24 can also be installed in the pipelines between the outlet of the heat exchanger 13 and the inlet of the air pump 21, the heat exchange medium inlet of the refrigerator 22, and the heat exchange medium inlet of the heater 23.

[0091] In some embodiments, as shown in FIG1 , the fixed bed flue gas purification system of the embodiment of the present disclosure further includes a regeneration gas treatment device 3 , which is connected to the purification device 1 and is used to treat the regeneration gas discharged from the purification device 1 .

[0092] It can be understood that when the purification device 1 operates in regeneration mode, the regeneration gas generated by desorption and regeneration of the adsorbent is discharged through the regeneration gas outlet of the shell 11 and transported to the regeneration gas treatment device 3 for reuse. The sulfur dioxide in the regeneration gas can be used to produce concentrated sulfuric acid and sodium metabisulfite, and the nitrogen oxides can be used to produce nitrogen fertilizer.

[0093] The following describes a control method for a fixed bed flue gas purification system according to an embodiment of the present disclosure.

[0094] According to the control method of the fixed bed flue gas purification system of the embodiment of the present disclosure, the fixed bed flue gas purification system includes a plurality of purification devices 1, the purification device 1 includes a shell 11, an adsorbent layer 12 arranged in the shell 11 and a heat exchanger 13 arranged in the shell 11 for exchanging heat with the adsorption layer, and the purification device 1 has a plurality of operating modes, including an adsorption mode.

[0095] The control method of the fixed bed flue gas purification system of the embodiment of the present disclosure includes:

[0096] The operating mode of each purification device 1 is determined.

[0097] According to the operation mode of each purification device 1 , a heat exchange medium is supplied to the heat exchanger 13 of the purification device 1 , and the temperature of the heat exchange medium corresponds to the operation mode of the purification device 1 .

[0098] In some embodiments, within a predetermined time period, at least one purification device 1 operates in adsorption mode. When any purification device 1 is in adsorption mode, a sub-zero temperature zone heat exchange medium is supplied to the heat exchanger 13 of the purification device 1 to cool the adsorbent layer 12 in the shell 11 and the flue gas entering the shell 11, so that the adsorbent layer 12 performs low-temperature adsorption purification on the flue gas in the sub-zero temperature zone.

[0099] The multiple operating modes also include a pre-cooling mode and a regeneration mode. When the purifier 1 is in the regeneration mode, a heat exchange medium is supplied to the heat exchanger 13 of the purifier 1 to desorb and regenerate the adsorbent layer 12. When the purifier 1 is in the pre-cooling mode, a heat exchange medium is supplied to the heat exchanger 13 of the purifier 1 to pre-cool the adsorbent layer 12 after heating and regeneration.

[0100] In some embodiments, any one of the plurality of purification devices 1 is operated in adsorption mode, regeneration mode, and pre-cooling mode in sequence, and the plurality of purification devices 1 are operated in different operation modes.

[0101] For example, the plurality of purification devices 1 include a first purification device 1A, a second purification device 1B, and a third purification device 1C.

[0102] in:

[0103] When the first purification device 1A operates in the pre-cooling mode, the second purification device 1B operates in the adsorption mode and the third purification device 1C operates in the regeneration mode.

[0104] When the first purification device 1A operates in the adsorption mode, the second purification device 1B operates in the regeneration mode, and the third purification device 1C operates in the pre-cooling mode.

[0105] When the first purification device 1A operates in the regeneration mode, the second purification device 1B operates in the pre-cooling mode, and the third purification device 1C operates in the adsorption mode.

[0106] Furthermore, the first purification device 1A operates in precooling mode, adsorption mode and regeneration mode in sequence, while the second purification device 1B operates in adsorption mode, regeneration mode and precooling mode in sequence, and the third purification device 1C operates in regeneration mode, precooling mode and adsorption mode in sequence.

[0107] In some embodiments, when any one of the first purification device 1A to the third purification device 1C operates in pre-cooling mode, adsorption mode and regeneration mode, a heat exchange medium at a first temperature, a heat exchange medium at a second temperature and a heat exchange medium at a third temperature are respectively introduced into the heat exchanger 13 of any one of the purification devices 1, wherein the first temperature is greater than or equal to the second temperature, and the third temperature is greater than the first temperature.

[0108] In some embodiments, the first temperature is 10°C to 30°C, the second temperature is -20°C to -10°C, and the third temperature is 200°C to 400°C.

[0109] For example, the heat exchange medium at the first temperature is room temperature air, the medium at the second temperature is low temperature air cooled by the refrigerator 22 , and the medium at the third temperature is hot air heated by the heater 23 .

[0110] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0112] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0113] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0114] In the present disclosure, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0115] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present disclosure.

Claims

1. A fixed bed flue gas purification system, comprising: A heat exchange medium supply device and a plurality of purification devices, the purification device comprising a shell, an adsorbent layer arranged in the shell and a heat exchanger arranged in the shell for exchanging heat with the adsorbent layer, the heat exchange medium supply device being used to supply heat exchange medium to the heat exchanger of the purification device, the purification device having a plurality of operation modes, the temperature of the heat exchange medium supplied by the heat exchange medium supply device to any purification device corresponding to the operation mode of the purification device, the plurality of operation modes comprising an adsorption mode, in the adsorption mode, the heat exchange medium supply device continuously supplies heat exchange medium in a sub-zero temperature zone to the heat exchanger to cool the adsorbent layer in the shell and the flue gas introduced into the shell, so that the adsorbent layer performs low-temperature adsorption purification on the flue gas in the sub-zero temperature zone, the plurality of purification devices being connected in parallel with each other, and within a predetermined time period, at least one of the purification devices operates in the adsorption mode.

2. The fixed bed type flue gas purification system according to claim 1, wherein a first support member and a second support member are provided in the shell, the first support member and the second support member separate the inner cavity of the shell into an air inlet cavity, an adsorption cavity and an exhaust cavity arranged in sequence along the vertical direction, the adsorbent layer is arranged in the adsorption cavity, the air inlet cavity is communicated with the flue gas inlet of the shell, and the exhaust cavity is communicated with the flue gas outlet of the shell; The heat exchanger is a heat exchange tube arranged in the adsorption chamber, and the heat exchange tube is serpentine, spiral or vortex shaped.

3. The fixed bed flue gas purification system according to claim 1 or 2, wherein the heat exchange medium supply device is one, and the one heat exchange medium supply device is used to supply heat exchange medium of different temperatures to multiple purification devices, or the heat exchange medium supply device is multiple and corresponds one-to-one to multiple purification devices.

4. The fixed bed flue gas purification system according to any one of claims 1 to 3, wherein the plurality of operation modes further include a precooling mode and a regeneration mode, the plurality of purification devices include a first purification device, a second purification device and a third purification device, the heat exchange medium supply device includes a first heat exchange medium supply device, a second heat exchange medium supply device and a third heat exchange medium supply device, The first heat exchange medium supply device is used to supply a heat exchange medium at a first temperature, a heat exchange medium at a second temperature, or a heat exchange medium at a third temperature to the first purification device, so that the first purification device operates in a precooling mode, an adsorption mode, or a regeneration mode. The second heat exchange medium supply device is used to supply the heat exchange medium at the first temperature, the heat exchange medium at the second temperature, or the heat exchange medium at the third temperature to the second purification device, so that the second purification device operates in a precooling mode, an adsorption mode, or a regeneration mode. The third heat exchange medium supply device is used to supply the heat exchange medium of the first temperature, the second temperature or a heat exchange medium at a third temperature so that the third purification device operates in a precooling mode, an adsorption mode or a regeneration mode, The first temperature is 10°C to 30°C, the second temperature is -20°C to -10°C, and the third temperature is 200°C to 400°C.

5. The fixed bed flue gas purification system according to claim 4, wherein the first to third heat exchange medium supply devices also include a four-way valve, the four-way valve having a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port is connected to a first medium source for providing a heat exchange medium at a first temperature, the second valve port is connected to a second medium source for providing a heat exchange medium at a second temperature, the third valve port is connected to a third medium source for providing a heat exchange medium at a third temperature, the fourth valve port is connected to the heat exchanger, the first medium source is room temperature air, the second medium source is low-temperature air cooled by a refrigerator, and the third medium source is hot air heated by a heater.

6. The fixed bed flue gas purification system according to any one of claims 1 to 5, further comprising a regeneration gas treatment device, wherein the regeneration gas treatment device is connected to the purification device and is used to treat the regeneration gas discharged from the purification device.

7. A control method for a fixed bed flue gas purification system, wherein the fixed bed flue gas purification system comprises a plurality of purification devices, the purification devices comprising a shell, an adsorbent layer disposed in the shell, and a heat exchanger disposed in the shell for exchanging heat with the adsorption layer, the purification devices having a plurality of operation modes, the plurality of operation modes including an adsorption mode, the control method comprising: Determine the operating mode of each purification unit; According to the operation mode of each purification device, supplying a heat exchange medium to the heat exchanger of the purification device, wherein the temperature of the heat exchange medium corresponds to the operation mode of the purification device; During a predetermined time period, at least one of the purification devices operates in the adsorption mode. When any purification device is in the adsorption mode, a heat exchange medium in the sub-zero temperature zone is supplied to the heat exchanger of the purification device to cool the adsorbent layer in the shell and the flue gas passing into the shell, so that the adsorbent layer performs low-temperature adsorption purification on the flue gas in the sub-zero temperature zone.

8. The control method of the fixed bed flue gas purification system according to claim 7, wherein the plurality of operation modes further include a precooling mode and a regeneration mode, and the plurality of purification devices include a first purification device, a second purification device and a third purification device, wherein: When the first purification device operates in the precooling mode, the second purification device operates in the adsorption mode and the third purification device operates in the regeneration mode; When the first purification device operates in the adsorption mode, the second purification device operates in the regeneration mode. The third purification device operates in the precooling mode; When the first purification device operates in the regeneration mode, the second purification device operates in the precooling mode, and the third purification device operates in the adsorption mode.

9. The control method of a fixed bed flue gas purification system according to claim 8, wherein the first purification device is operated in sequence in the precooling mode, the adsorption mode and the regeneration mode, while the second purification device is operated in sequence in the adsorption mode, the regeneration mode and the precooling mode, and the third purification device is operated in sequence in the regeneration mode, the precooling mode and the adsorption mode.

10. The control method of a fixed bed flue gas purification system according to claim 8, wherein when any one of the first to third purification devices operates the pre-cooling mode, the adsorption mode and the regeneration mode, a heat exchange medium at a first temperature, a heat exchange medium at a second temperature and a heat exchange medium at a third temperature are respectively introduced into the heat exchanger of any one of the purification devices, the heat exchange medium at the first temperature is normal temperature air of 10°C to 30°C, the heat exchange medium at the second temperature is low-temperature air of -20°C to -10°C cooled by a refrigerator, and the heat exchange medium at the third temperature is hot air of 200°C to 400°C heated by a heater.

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