A flue gas desulfurization system

Abstract

The application specifically relates to a flue gas desulfurization system, belonging to the field of gas purification, which comprises: at least two reactors for regenerating adsorbents in the reactors or adsorbing and desulfurizing flue gas; a pretreatment device in communication with the reactors through a flue gas inlet pipe, wherein the flue gas inlet pipe is provided with a flue gas control valve; a regeneration device for introducing a regeneration gas into the reactors, in communication with the reactors through a regeneration gas inlet pipe and provided with a regeneration gas control valve; and a sweeping device for introducing a sweeping gas into the reactors and in communication with a gas outlet of the regeneration device. The flue gas desulfurization adsorbent taking metal oxide as an active center can effectively remove sulfur in flue gas, at least two reactors are arranged, one is used for regeneration and the other is used for desulfurization, the reactors are switched when the sulfur content in the purified flue gas approaches a standard, the flue gas desulfurization process can be continuously carried out, and thus the flue gas desulfurization device can meet the emission standard.

Description

Technical Field

[0001] This application relates to the field of gas purification, and more particularly to a flue gas desulfurization system. Background Technology

[0002] Sulfide emission standards are becoming increasingly stringent, and sulfur recovery units in natural gas purification plants face requirements for tail gas emission reduction. Refinery sulfur recovery units have even stricter requirements, and conventional processes are no longer sufficient to meet the standards. Currently, flue gas desulfurization mainly includes alkaline scrubbing, ammonia methods, solvent absorption, and complexed iron methods. Domestically, sulfur recovery or flue gas purification in sulfur recovery units primarily uses alkaline solutions or solvents to absorb sulfur dioxide. However, these two processes generate saline wastewater. Although the flow rate of saline wastewater is not high, its concentration is very high, making it difficult to treat even after entering a wastewater treatment plant. It is generally treated through dilution, but these two processes also have certain limitations. Summary of the Invention

[0003] This application provides a flue gas desulfurization system to solve the technical problem that existing flue gas desulfurization devices cannot meet emission standards.

[0004] This application provides a flue gas desulfurization system, comprising:

[0005] At least two reactors are used to regenerate the adsorbent in the reactors or to adsorb and desulfurize the flue gas.

[0006] A pretreatment device is connected to the reactor via a flue gas inlet pipe, and the flue gas inlet pipe is equipped with a flue gas control valve;

[0007] A regeneration device for introducing regeneration gas into the reactor, the regeneration device being connected to the reactor via a regeneration gas inlet pipe, the regeneration gas inlet pipe being equipped with a regeneration gas control valve;

[0008] A purging device is used to introduce purging gas into the reactor, and the purging device is connected to the gas outlet of the regeneration device.

[0009] Optionally, the regeneration device includes:

[0010] A hydrogenation reactor is used to reduce sulfur dioxide and sulfur in the regeneration tail gas produced by the reactor to hydrogen sulfide. The hydrogenation reactor is connected to the reactor through the regeneration tail gas outlet pipe.

[0011] The tail gas absorption tower is used to absorb hydrogen sulfide. The tail gas absorption tower is provided with a lean liquid inlet, a rich liquid outlet, a tail gas inlet, and a purified tail gas outlet. The tail gas inlet of the tail gas absorption tower is connected to the hydrogenation reactor. The tail gas absorption tower is connected to the pretreatment device through the purified tail gas outlet and a regeneration gas inlet pipe.

[0012] Optionally, the regeneration device further includes a pressurization device, the air inlet of which is connected to the purified exhaust gas outlet of the exhaust gas absorption tower, and the air outlet of which is connected to the reactor.

[0013] Optionally, the pretreatment device includes:

[0014] An incinerator, wherein the incinerator is provided with an air inlet, a fuel gas inlet, and a feed gas inlet;

[0015] A cooling device is used to adjust the temperature of the flue gas at the outlet of the incinerator. The incinerator is connected to the cooling device, and the cooling device is connected to the reactor through a flue gas inlet pipe.

[0016] Optionally, the cooling device is a steam heat exchanger.

[0017] Optionally, the system further includes a purified flue gas heat exchanger, which is connected to the reactor.

[0018] Optionally, the pretreatment device includes:

[0019] A sulfur recovery unit heat exchanger is used to heat the flue gas, and the sulfur recovery unit heat exchanger is connected to the reactor through a flue gas inlet pipe;

[0020] A temperature control pipeline is used to regulate the flue gas temperature at the outlet of the heat exchanger of the sulfur recovery device. One end of the temperature control pipeline is connected to the inlet of the heat exchanger of the sulfur recovery device, and the other end of the temperature control pipeline is connected to the outlet of the heat exchanger of the sulfur recovery device. The temperature control pipeline is equipped with a temperature control valve.

[0021] Optionally, the system further includes:

[0022] A preheating device is used to preheat the flue gas, and the preheating device is connected to the heat exchanger of the sulfur recovery device.

[0023] Optionally, the reactor is connected to the preheating device, which is used to recover heat from the purified exhaust gas and use the heat to preheat the flue gas.

[0024] Optionally, the system further includes a heating device, the air inlet of which is connected to the regeneration device and the purging device, and the air outlet of which is connected to the reactor.

[0025] The technical solutions provided in this application have the following advantages compared with the prior art:

[0026] This application embodiment uses metal oxide as the active center of the flue gas desulfurization adsorbent, which can effectively remove sulfur from the flue gas. At the same time, at least two reactors are set up, one for regeneration and one for desulfurization, so that the flue gas desulfurization process can be carried out continuously. When the sulfur content in the purified flue gas is close to the standard, the reactor is switched so that the flue gas desulfurization device can meet the emission standards. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a flue gas desulfurization system provided in Embodiment 1 of this application;

[0030] Figure 2 This is a schematic diagram of a flue gas desulfurization system provided in Embodiment 2 of this application;

[0031] Figure 3 This is a schematic diagram of a flue gas desulfurization system provided in Embodiment 3 of this application.

[0032] Figure label:

[0033] 1-First reactor, 2-Second reactor;

[0034] 3-Pretreatment device, 31-Flue gas inlet pipe, 32-First flue gas control valve, 33-Second flue gas control valve, 34-Incinerator, 35-Cooling device, 36-Incinerator blower, 37-Sulfur recovery device heat exchanger, 38-Temperature control pipeline, 381-Temperature control valve, 382-Temperature sensor.

[0035] 4-Regeneration device, 41-Regeneration gas inlet pipe, 411 First regeneration gas control valve, 412-Second regeneration gas control valve, 42-Regeneration tail gas outlet pipe, 421 First regeneration tail gas control valve, 422-Second regeneration tail gas control valve, 43-Hydrogenation reactor, 44-Quick cooler tower, 441-Quick cooler water pump, 442-Quick cooler water filter, 443-Quick cooler water cooler, 45-Tail gas absorption tower, 46-Pressure booster device;

[0036] 5-Heating device, 6-Purge device, 7-Purified flue gas heat exchanger, 71-Purified flue gas outlet pipe, 72-First purified flue gas control valve, 73-Second purified flue gas control valve, 8-Chimney, 9-Preheating device. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Example 1

[0039] like Figure 1 As shown, a flue gas desulfurization system includes two reactors, a pretreatment device 3, a regeneration device 4, a heating device 5, a purging device 6, a purified flue gas heat exchanger 7, and a chimney 8. One reactor is used to regenerate the adsorbent, and the other is used for adsorption desulfurization of the flue gas. The pretreatment device 3 is used to introduce flue gas into the reactor for adsorption desulfurization. After adsorption, the purified flue gas recovers heat through the purified flue gas heat exchanger 7 and is discharged through the chimney 8. The regeneration device 4 is used to introduce regeneration gas heated by the heating device 5 into the reactor that needs to be regenerated and to treat the regeneration tail gas generated during reactor regeneration.

[0040] The reactor contains an adsorbent. In this embodiment, the reactor is an adsorption / desorption tower. In this application embodiment, the reactor is a vertical reactor, but it can also be a horizontal reactor. The adsorbent is a metal oxide, and it includes a first reactor 1 and a second reactor 2. The following reaction occurs in the first reactor 1 for adsorption desulfurization:

[0041] MxO + SO2 + 1 / 2O2 → MxSO4;

[0042] The following reaction occurs in the second reactor 2 for adsorbent regeneration:

[0043] MxSO4 + H2 → MxO + SO2 + H2O.

[0044] The pretreatment device 3 is connected to the reactor through a flue gas inlet pipe 31. The flue gas inlet pipe 31 is equipped with a flue gas control valve. In this embodiment, there are two flue gas control valves, namely a first flue gas control valve 32 and a second flue gas control valve 33, which correspond to the first reactor 1 and the second reactor 2, respectively. In this embodiment, the flue gas control valve controls the opening and closing of the flue gas inlet pipe 31, i.e., the flue gas control valve is a switching valve. It can be understood that the flue gas control valve described in this embodiment can also be other types of valves with switching functions, such as flow valves.

[0045] The pretreatment device 3 includes:

[0046] The incinerator 34 is used to mix fuel gas and feed gas, so that the flue gas can be fully burned in the incinerator 34, and the sulfur in the feed gas is oxidized into sulfur dioxide so that the reactor can absorb it fully. The incinerator 34 is provided with an air inlet, a fuel gas inlet and a feed gas inlet. In this embodiment, the feed gas inlet of the incinerator 34 is connected to the purified tail gas outlet of the tail gas absorption tower 45 to burn the residual hydrogen sulfide and other sulfides in the purified tail gas into sulfur dioxide.

[0047] Cooling device 35 is used to adjust the temperature of the flue gas at the outlet of the incinerator 34 and maintain the temperature at 200℃-600℃. The incinerator 34 is connected to the cooling device 35, and the cooling device 35 is connected to the reactor through the flue gas inlet pipe 31. In this embodiment, the cooling device 35 is a steam heat exchanger.

[0048] The incinerator blower 36 is connected to the air inlet of the incinerator 34.

[0049] The flue gas comes from the regeneration device 4 of the reactor, mixes and burns with the fuel gas in the incinerator 34, and is supplied with oxygen by the incinerator blower 36 to make the combustion more complete. The flue gas after combustion enters the cooling device 35, which maintains the temperature of the flue gas at 200℃-600℃. In this embodiment, the flue gas then enters the first reactor 1 for adsorption and desulfurization.

[0050] The regeneration device 4 is used to regenerate the regeneration tail gas produced by the reactor, converting the regeneration tail gas into regeneration gas, and then reintroducing the regeneration gas into the reactor. The regeneration device 4 is connected to the reactor through a regeneration gas inlet pipe 41 to introduce regeneration gas into the reactor. The regeneration gas inlet pipe 41 is equipped with regeneration gas control valves. In this embodiment, there are two regeneration gas control valves: a first regeneration gas control valve 411 and a second regeneration gas control valve 412, corresponding to the first reactor 1 and the second reactor 2, respectively. The reactor is connected to the regeneration device 4 through a regeneration tail gas outlet pipe 42 to introduce regeneration tail gas into the regeneration device 4. The regeneration tail gas outlet pipe 42 is equipped with regeneration tail gas control valves. In this embodiment, there are two regeneration tail gas control valves: a first regeneration tail gas control valve 421 and a second regeneration tail gas control valve 422, corresponding to the first reactor 1 and the second reactor 2, respectively.

[0051] Specifically, the regeneration device 4 includes:

[0052] Hydrogenation reactor 43 is used to reduce sulfur dioxide in the regeneration tail gas produced by the reactor to hydrogen sulfide. The hydrogenation reactor 43 is connected to the reactor through the regeneration tail gas outlet pipe.

[0053] A quench tower 44 is used to cool the outlet gas of the hydrogenation reactor 43 so that it can be absorbed by the lean liquid in the tail gas absorption tower 45. The outlet of the quench tower 44 is sequentially equipped with a quench water pump 441, a quench water filter 442, and a quench water cooler 443. The outlet of the quench water cooler 443 is connected to the inlet of the quench tower 44. In this embodiment, the quench tower 44 uses quench water to spray and cool the reduced tail gas. The quench water enters the quench water filter 442 through the quench water pump 441, is cooled by the quench water cooler 443 after filtration, and then enters the quench tower 44 for recycling. Part of the quench water is discharged from the outlet of the quench water filter 442.

[0054] A tail gas absorption tower 45 is used to absorb residual hydrogen sulfide in the tail gas. The tail gas absorption tower 45 is provided with a lean liquid inlet, a rich liquid outlet, a tail gas inlet, and a purified tail gas outlet. In this embodiment, a hydrogen sulfide lean liquid is introduced into the tail gas absorption tower 45. After absorbing hydrogen sulfide gas in the tail gas absorption tower 45, it is converted into a hydrogen sulfide-containing rich liquid and discharged from the rich liquid outlet. The tail gas absorption tower 45 is connected to the hydrogenation reactor through the tail gas inlet and to the pretreatment device through the purified tail gas outlet.

[0055] The pressurization device 46 has its air inlet connected to the purified exhaust gas outlet of the exhaust gas absorption tower, and its air outlet connected to the reactor through the regenerated gas inlet pipe 41.

[0056] The regeneration tail gas from the second reactor 2 enters the hydrogenation reactor 43. In the hydrogenation reactor 43, sulfur dioxide is reduced to hydrogen sulfide gas, which then enters the quench tower 44. Because the outlet gas temperature of the hydrogenation reactor 43 is high, and high-temperature hydrogen sulfide gas is detrimental to lean solution absorption, the quench tower 44 is installed. Hydrogen sulfide, other sulfides, and reducing gases are cooled by the quench tower 44 and then enter the tail gas absorption tower 45 from the tail gas inlet. A hydrogen sulfide lean solution is then introduced into the tail gas absorption tower 45, where it absorbs the hydrogen sulfide gas and transforms into a hydrogen sulfide-rich solution. The rich liquid is discharged from the outlet, and the gas exits from the purified tail gas outlet of the tail gas absorption tower 45. At this time, the gas contains hydrogen sulfide that has not been completely absorbed, other sulfides, and reducing gases. The gas is then divided into two streams. One stream is used as reducing gas, which is pressurized by the pressurizing device 46, heated by the heating device 5, and enters the second reactor 2 to regenerate the adsorbent therein. The other stream is used as feed gas and enters the incinerator 34 for combustion, which burns the hydrogen sulfide that has not been completely absorbed by the tail gas absorption tower and other sulfides that cannot be absorbed into sulfur dioxide. Then, it enters the first reactor 1 and is absorbed by the adsorbent in the first reactor 1.

[0057] The purging device 6 is used to introduce purging gas into the reactor, and the purging device 6 is connected to the gas outlet of the regeneration device 4.

[0058] In this embodiment, the purging device 6 is a nitrogen pipeline network, which is used to purge the bed in the second reactor 2 with nitrogen gas heated by the heating device 5 before regenerating the second reactor 2. The purged gas is discharged to the chimney 8 through the second reactor 2. After purging for a certain period of time and detecting that the oxygen content in the purging gas is less than 0.5%, the regeneration device 4 is turned on to introduce regeneration gas into the second reactor 2.

[0059] In some embodiments, the purified flue gas heat exchanger 7 is connected to the reactor via a purified flue gas outlet pipe 71 to collect the purified flue gas generated after adsorption by the reactor and to introduce it into the chimney 8. The purified flue gas outlet pipe 71 is equipped with a purified flue gas control valve. In this embodiment, the purified flue gas control valve includes a first purified flue gas control valve 72 and a second purified flue gas control valve 73, which correspond to the first reactor 1 and the second reactor 2, respectively.

[0060] In this embodiment, the first reactor 1 and the second reactor 2 are an adsorption tower and a desorption tower, respectively. The first flue gas control valve 32 and the first purified flue gas control valve 72 are open, and the first regeneration gas control valve 411 and the first regeneration tail gas control valve 421 are closed, so that the first reactor 1 is in an adsorption state. The second flue gas control valve 33 and the second purified flue gas control valve 73 are closed, and the second regeneration gas control valve 412 and the second regeneration tail gas control valve 422 are open, so that the second reactor 2 is in a desorption state. Flue gas enters the first reactor 1 through flue gas inlet pipe 31. In the first reactor 1, sulfur dioxide is oxidized and combines with metal oxides to form metal sulfates. The purified flue gas recovers its heat through the purified flue gas heat exchanger 7 before being discharged through the chimney 8. Regeneration gas enters the second reactor 2 through regeneration gas inlet pipe 41. In the second reactor 2, metal sulfates are reduced to sulfur dioxide and metal oxides. Sulfur dioxide, as regeneration tail gas, enters the regeneration unit 4 through the regeneration tail gas outlet pipe and mixes with hydrogen in the hydrogenation reactor 43. Sulfur dioxide is reduced to hydrogen sulfide. After being cooled by the quench tower 44, most of the hydrogen sulfide is removed by the tail gas absorption tower 45. Unreacted hydrogen sulfide, other sulfides, hydrogen, and purging nitrogen are then used as regeneration gas and reintroduced into the second reactor 2. When the SO2 concentration in the purified flue gas at the outlet of the first reactor 1 approaches 50 mg / Nm³... 3 Or 100mg / Nm 3 (Based on dry basis, 3% O2) When the first flue gas control valve 32 and the first purified flue gas control valve 72 are closed, the first regeneration gas control valve 411 and the first regeneration tail gas control valve 421 are opened, so that the first reactor 1 enters the desorption state; when the concentration of SO2 in the regeneration tail gas at the outlet of the second reactor 2 drops to 10 mg / Nm³ 3 When the second regeneration gas control valve 412 and the second purified flue gas control valve 73 are closed, the second flue gas control valve 33 and the second regeneration tail gas control valve 422 are opened, and the second reactor 2 enters the adsorption state.

[0061] Using metal oxides as the active center of the flue gas desulfurization adsorbent can effectively remove sulfur from the flue gas. At least two reactors are set up, one for regeneration and one for desulfurization, so that the flue gas desulfurization process can be carried out continuously. When the sulfur content in the purified flue gas is close to the standard, the reactor is switched so that the flue gas desulfurization device can meet the emission standards.

[0062] Example 2

[0063] like Figure 2As shown, a flue gas desulfurization system includes two reactors, a pretreatment device 3, a regeneration device 4, a heating device 5, a purging device 6, a purified flue gas heat exchanger 7, and a chimney 8. One reactor is used to regenerate the adsorbent, and the other is used to perform adsorption desulfurization on the flue gas. The pretreatment device 3 is used to introduce flue gas into the reactor for adsorption desulfurization. After adsorption, the purified flue gas recovers heat through the purified flue gas heat exchanger 7 and is then discharged through the chimney 8. The regeneration device 4 is used to introduce regeneration gas heated by the heating device 5 into the reactor that needs to be regenerated.

[0064] The reactor contains an adsorbent. In this embodiment, the reactor is an adsorption / desorption tower, specifically, it can be a vertical reactor or a horizontal reactor, including a first reactor 1 and a second reactor 2. The following reaction occurs in the first reactor 1 for adsorption desulfurization:

[0065] MxO + SO2 + 1 / 2O2 → MxSO4;

[0066] The following reaction occurs in the second reactor 2 for adsorbent regeneration:

[0067] MxSO4 + H2 → MxO + SO2 + H2O.

[0068] The pretreatment device 3 is connected to the reactor through a flue gas inlet pipe 31. The flue gas inlet pipe 31 is equipped with a flue gas control valve. In this embodiment, there are two flue gas control valves, namely a first flue gas control valve 32 and a second flue gas control valve 33, which correspond to the first reactor 1 and the second reactor 2, respectively. In this embodiment, the flue gas control valve controls the opening and closing of the flue gas inlet pipe 31, i.e., the flue gas control valve is a switching valve. It can be understood that the flue gas control valve described in this embodiment can also be other types of valves with switching functions, such as flow valves.

[0069] The pretreatment device 3 includes:

[0070] The incinerator 34 is used to mix fuel gas and feed gas, so that the flue gas is fully combusted in the incinerator 34, and the sulfur in the feed gas is oxidized into sulfur dioxide so that the reactor can absorb it fully. The incinerator 34 is provided with an air inlet, a fuel gas inlet and a feed gas inlet.

[0071] Cooling device 35 is used to adjust the temperature of the flue gas at the outlet of the incinerator 34 and maintain the temperature at 200℃-600℃. The incinerator 34 is connected to the cooling device 35, and the cooling device 35 is connected to the reactor through the flue gas inlet pipe 31. In this embodiment, the cooling device 35 is a steam heat exchanger.

[0072] The incinerator blower 36 is connected to the air inlet of the incinerator 34.

[0073] The feed gas comes from the tail gas absorption tower, mixes and burns with the fuel gas in the incinerator 34, and is supplied with oxygen by the incinerator blower 36 to make the combustion more complete. The flue gas after combustion enters the cooling device 35, which maintains the temperature of the flue gas at 200℃-600℃. In this embodiment, the flue gas then enters the first reactor 1 for adsorption and desulfurization.

[0074] The regeneration device 4 is used to introduce regeneration gas into the reactor. The regeneration device 4 is connected to the reactor via a regeneration gas inlet pipe 41, which is equipped with regeneration gas control valves. In this embodiment, there are two regeneration gas control valves: a first regeneration gas control valve 411 and a second regeneration gas control valve 412, corresponding to the first reactor 1 and the second reactor 2, respectively. The regeneration device 4 includes a hydrogen pipeline network, which is connected to the inlet end of the heating device 5. The outlet end of the heating device 5 is connected to the regeneration gas control valves. The reactor is connected to other processes via a regeneration tail gas outlet pipe 42 for collecting regeneration tail gas. The regeneration tail gas outlet pipe 42 is equipped with a regeneration tail gas control valve. In this embodiment, there are two regeneration tail gas control valves: a first regeneration tail gas control valve 421 and a second regeneration tail gas control valve 422, corresponding to the first reactor 1 and the second reactor 2, respectively.

[0075] The purging device 6 is used to introduce purging gas into the reactor and dilute the hydrogen concentration. The purging device 6 is connected to the gas inlet of the heating device 5.

[0076] In this embodiment, instead of using alkaline washing or other techniques to recover sulfur dioxide from the flue gas, hydrogen-containing gas is used directly as the regeneration gas to regenerate the reactor. The regenerated tail gas can be sent to the sulfur production furnace for recycling.

[0077] In some embodiments, the purified flue gas heat exchanger 7 is connected to the reactor via a purified flue gas outlet pipe 71 to collect the purified flue gas generated after adsorption by the reactor and to introduce it into the chimney 8. The purified flue gas outlet pipe 71 is equipped with a purified flue gas control valve. In this embodiment, the purified flue gas control valve includes a first purified flue gas control valve 72 and a second purified flue gas control valve 73, which correspond to the first reactor 1 and the second reactor 2, respectively.

[0078] Example 3

[0079] like Figure 3As shown, a flue gas desulfurization system includes two reactors, a pretreatment device 3, a regeneration device 4, a heating device 5, a purging device 6, a preheating device 9, and a chimney 8. One reactor is used to regenerate the adsorbent, and the other is used to perform adsorption desulfurization on the flue gas. The pretreatment device 3 is used to introduce flue gas into the reactor for adsorption desulfurization. The purified flue gas after adsorption recovers heat through the preheating device 9 and is discharged through the chimney 8. The regeneration device 4 is used to introduce regeneration gas heated by the heating device 5 into the reactor that needs to be regenerated.

[0080] The reactor contains an adsorbent. In this embodiment, the reactor is an adsorption / desorption tower, specifically, it can be a vertical reactor or a horizontal reactor, including a first reactor 1 and a second reactor 2. The following reaction occurs in the first reactor 1 for adsorption desulfurization:

[0081] MxO + SO2 + 1 / 2O2 → MxSO4;

[0082] The following reaction occurs in the second reactor 2 for adsorbent regeneration:

[0083] MxSO4 + H2 → MxO + SO2 + H2O.

[0084] The pretreatment device 3 is connected to the reactor via a flue gas inlet pipe 31. The flue gas inlet pipe 31 is equipped with a flue gas control valve. In this embodiment, there are two flue gas control valves: a first flue gas control valve 32 and a second flue gas control valve 33, which correspond to the first reactor 1 and the second reactor 2, respectively. A temperature sensor 382 is provided in front of the flue gas control valve. In this embodiment, the flue gas control valve controls the opening and closing of the flue gas inlet pipe 31, i.e., the flue gas control valve is a switching valve. It can be understood that the flue gas control valve described in this embodiment can also be other types of valves with switching functions, such as flow valves.

[0085] The pretreatment device 3 includes:

[0086] The sulfur recovery device heat exchanger 37 is used to heat the flue gas. The sulfur recovery device heat exchanger 37 is connected to the reactor through the flue gas inlet pipe 31. In this embodiment, the preheating device 9 is connected to the sulfur recovery device heat exchanger 37 to preheat the flue gas.

[0087] Temperature control pipeline 38 is used to regulate the flue gas temperature at the outlet of the heat exchanger 37 of the sulfur recovery device. One end of the temperature control pipeline 38 is connected to the inlet of the heat exchanger 37 of the sulfur recovery device, and the other end of the temperature control pipeline 38 is connected to the outlet of the heat exchanger 37 of the sulfur recovery device. The temperature control pipeline is equipped with a temperature control valve 381.

[0088] The regeneration device 4 is used to introduce regeneration gas into the reactor. The regeneration device 4 is connected to the reactor via a regeneration gas inlet pipe 41, which is equipped with regeneration gas control valves. In this embodiment, there are two regeneration gas control valves: a first regeneration gas control valve 411 and a second regeneration gas control valve 412, corresponding to the first reactor 1 and the second reactor 2, respectively. The regeneration device 4 includes a hydrogen pipeline network, which is connected to the inlet end of the heating device 5. The outlet end of the heating device 5 is connected to the regeneration gas control valves. The reactor is connected to other processes via a regeneration tail gas outlet pipe 42 for collecting regeneration tail gas. The regeneration tail gas outlet pipe 42 is equipped with a regeneration tail gas control valve. In this embodiment, there are two regeneration tail gas control valves: a first regeneration tail gas control valve 421 and a second regeneration tail gas control valve 422, corresponding to the first reactor 1 and the second reactor 2, respectively.

[0089] The purging device 6 is used to introduce purging gas into the reactor, and the purging device 6 is connected to the air inlet of the heating device 5.

[0090] In this embodiment, the flue gas first passes through the preheating device 9, which recovers and preheats the flue gas by purifying it. Then, a portion of the flue gas enters the sulfur recovery device heat exchanger 37 for further heat exchange, raising its temperature to the reaction temperature and becoming high-temperature flue gas. The other portion enters the temperature control pipeline 38 to mix with the high-temperature flue gas as low-temperature flue gas. The temperature of the mixed flue gas is measured by the temperature sensor 382 as it enters the first reactor 1. When the temperature of the flue gas entering the reactor is high, the temperature sensor 382 sends a signal to the temperature control valve 381, which controls the low-temperature flue gas in the temperature control pipeline 38. The flow rate of warm flue gas is increased to stabilize the flue gas entering the reactor at 200℃-600℃. When the temperature of the flue gas entering the reactor is low, the temperature sensor 382 sends a signal to the temperature control valve 381. The temperature control valve 381 controls the flow rate of low-temperature flue gas in the temperature control pipeline 38 to reduce the temperature of the flue gas entering the reactor at 200℃-600℃. After the flue gas is desulfurized in the first reactor 1, it is discharged into the chimney 8 after the heat is recovered by the preheating device 9. The regeneration gas comes from the hydrogen pipeline and is mixed with nitrogen to enter the second reactor 2. After the desorption process occurs in the second reactor 2, the regeneration tail gas is recycled to the furnace in front of the device for recycling.

[0091] Flue gas desulfurization adsorbents using metal oxides as active components can effectively remove sulfur from flue gas. At least two reactors are set up, one for regeneration and one for desulfurization, so that the flue gas desulfurization process can be carried out continuously. When the sulfur content in the purified flue gas approaches the standard, the reactor is switched so that the flue gas desulfurization device can meet the emission standards.

[0092] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0093] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A flue gas desulfurization system, characterized in that, include: At least two reactors are used to regenerate the adsorbent in the reactors or to adsorb and desulfurize the flue gas. A pretreatment device is connected to the reactor via a flue gas inlet pipe, and the flue gas inlet pipe is equipped with a flue gas control valve; A regeneration device for introducing regeneration gas into the reactor, the regeneration device being connected to the reactor via a regeneration gas inlet pipe, the regeneration gas inlet pipe being equipped with a regeneration gas control valve; A purging device is used to introduce purging gas into the reactor, and the purging device is connected to the gas outlet of the regeneration device; The regeneration device includes: A hydrogenation reactor is used to reduce sulfur dioxide and sulfur in the regeneration tail gas produced by the reactor to hydrogen sulfide. The hydrogenation reactor is connected to the reactor through a regeneration tail gas outlet pipe. A tail gas absorption tower is used to absorb hydrogen sulfide. The tail gas absorption tower is provided with a lean liquid inlet, a rich liquid outlet, a tail gas inlet, and a purified tail gas outlet. The tail gas inlet of the tail gas absorption tower is connected to the hydrogenation reactor, and the tail gas absorption tower is connected to the pretreatment device through the purified tail gas outlet. The regeneration device also includes a pressurization device, the air inlet of which is connected to the purified exhaust gas outlet of the exhaust gas absorption tower, and the air outlet of which is connected to the reactor through a regeneration gas inlet pipe. The pretreatment device includes: An incinerator, wherein the incinerator is provided with an air inlet, a fuel gas inlet, and a feed gas inlet; A cooling device is used to adjust the temperature of the flue gas at the outlet of the incinerator. The incinerator is connected to the cooling device, and the cooling device is connected to the reactor through a flue gas inlet pipe.

2. The flue gas desulfurization system according to claim 1, characterized in that, The system also includes a flue gas heat exchanger, which is connected to the reactor.

3. The flue gas desulfurization system according to claim 1, characterized in that, The pretreatment device includes: A sulfur recovery unit heat exchanger is used to heat the flue gas, and the sulfur recovery unit heat exchanger is connected to the reactor through a flue gas inlet pipe; A temperature control pipeline is used to regulate the flue gas temperature at the outlet of the heat exchanger of the sulfur recovery device. One end of the temperature control pipeline is connected to the inlet of the heat exchanger of the sulfur recovery device, and the other end of the temperature control pipeline is connected to the outlet of the heat exchanger of the sulfur recovery device. The temperature control pipeline is equipped with a temperature control valve.

4. The flue gas desulfurization system according to claim 1, characterized in that, The system also includes: A preheating device is used to preheat the flue gas, and the preheating device is connected to the heat exchanger of the sulfur recovery device; The reactor is connected to the preheating device, which is used to recover heat from the purified exhaust gas and use the heat to preheat the flue gas.

5. The flue gas desulfurization system according to claim 1, characterized in that, The system also includes a heating device, the air inlet of which is connected to the regeneration device and the purging device, and the air outlet of which is connected to the reactor.

6. The flue gas desulfurization system according to claim 1, characterized in that, The cooling device is a steam heat exchanger.

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