Flue gas low-temperature adsorption purification system

Abstract

The application discloses a flue gas low-temperature adsorption purification system, liquid phase fractions are discharged from a liquid outlet of a rectifying tower and enter the rectifying tower from a second cooling liquid inlet to rectify regenerated rich gas, so that the liquid phase fractions partially or wholly replace the cooling liquid to rectify the regenerated rich gas, thereby reducing the usage of the cooling liquid. When the liquid phase fractions partially or wholly replace the cooling liquid to rectify the regenerated rich gas, part of nitrogen oxides in the liquid phase fractions is released in the form of gas, that is, by partially or wholly replacing the cooling liquid with the liquid phase fractions to rectify the regenerated rich gas, the liquid phase fractions are continuously purified, thereby gradually reducing the content of nitrogen oxides in the liquid phase fractions and gradually increasing the purity of sulfur dioxide in the liquid phase fractions. The continuous purification of the liquid phase fractions in the rectifying tower can improve the utilization rate of the rectifying tower, so that the rectifying of the regenerated rich gas can be realized by a small number of rectifying towers, thereby reducing the number of the rectifying towers.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption purification, and in particular to a flue gas low-temperature adsorption purification system. Background Art

[0002] Pollutants such as sulfur dioxide and nitrogen oxides in coal-fired flue gas are very harmful to the human body. Before being discharged into the atmosphere, the coal-fired flue gas needs to be purified, and after purification, the sulfur resources need to be recycled. In the process of sulfur recycling, it is first necessary to separate the sulfur dioxide and nitrogen oxides in the flue gas from each other, and distillation is generally used. Distillation is a separation process that separates the components in a mixture by utilizing the different volatilities of the components. Distillation is usually carried out in a distillation tower, and the gas and liquid phases are contacted by countercurrent to carry out interphase heat and mass transfer. In the related technology, multiple distillation towers are set up to carry out multiple distillations to ensure the separation of sulfur dioxide and nitrogen oxides and the separation purity.

[0003] However, the method of separating sulfur dioxide and nitrogen oxides in the related art has a low utilization rate of the distillation tower, requires a large number of distillation towers, and consumes a large amount of coolant, which wastes resources. Summary of the Invention

[0004] The present invention aims to at least partially address one of the technical problems in the related art. To this end, embodiments of the present invention provide a flue gas low-temperature adsorption purification system that improves distillation tower utilization, thereby reducing the number of distillation towers, and reduces coolant consumption, thereby avoiding waste of resources.

[0005] The flue gas low-temperature adsorption purification system of an embodiment of the present invention includes a cooling tower, an adsorption tower and a regeneration tower connected in sequence. The cooling tower is used to cool the flue gas to low-temperature flue gas below zero degrees and supply it to the adsorption tower. The adsorbent layer in the adsorption tower is used to adsorb and purify the low-temperature flue gas into clean flue gas. The adsorption-saturated adsorbent in the adsorption tower can be supplied to the regeneration tower for regeneration to produce regenerated adsorbent and regenerated rich gas. The regenerated adsorbent can be supplied to the adsorption tower. The regeneration tower has a regenerated rich gas outlet for discharging the regenerated rich gas. The flue gas low-temperature adsorption purification system also includes a distillation tower and a condenser liquefier. The distillation tower has a first cooling liquid inlet, a second cooling liquid inlet, a liquid outlet and a third cooling liquid inlet, the first cooling liquid inlet is used to supply cooling liquid into the distillation tower, the distillation tower is connected with the regeneration rich gas outlet, so that the regeneration rich gas discharged from the regeneration rich gas outlet enters the distillation tower through the regeneration rich gas inlet and exchanges heat with the cooling liquid for distillation to produce a gas phase fraction and a liquid phase fraction, the liquid outlet is connected with the second cooling liquid inlet, so that the liquid phase fraction flows out of the distillation tower through the liquid outlet and flows into the distillation tower through the second cooling liquid inlet to distill the gas phase fraction. The regenerated rich gas in the distillation tower is distilled and a portion of the nitrogen oxides in the liquid fraction is released; the condenser-liquefier has a gaseous fraction inlet and a condensate outlet, the gaseous fraction inlet is connected to the distillation tower, so that the gaseous fraction flowing out of the distillation tower enters the condenser-liquefier through the gaseous fraction inlet for condensation and produces non-condensable gas and condensate, and the condensate outlet is connected to the third inlet of the coolant, so that the condensate discharged from the condensate outlet flows into the distillation tower through the third inlet of the coolant to utilize the condensate to perform low-temperature distillation on the regenerated rich gas.

[0006] In the flue gas low-temperature adsorption purification system according to an embodiment of the present invention, the liquid phase fraction is discharged from the distillation tower through the liquid outlet and enters the distillation tower through the second coolant inlet to distill the regenerated rich gas, replacing the coolant in distilling the regenerated rich gas, thereby reducing the amount of coolant used. When the liquid phase fraction produced in the distillation tower reaches a preset amount, the liquid phase fraction can completely replace the coolant in distilling the regenerated rich gas. During the subsequent operation of the flue gas low-temperature adsorption purification system according to an embodiment of the present invention, there is no need to add additional coolant to the distillation tower, thereby greatly reducing the amount of coolant used. When the liquid phase fraction partially or completely replaces the coolant in distilling the regenerated rich gas, some nitrogen oxides in the liquid phase fraction are released in the form of gas, thereby reducing the content of nitrogen oxides in the liquid phase fraction and increasing the purity of sulfur dioxide in the liquid phase fraction. That is to say, by partially or completely replacing the coolant with the liquid fraction to distill the regenerated rich gas, it is equivalent to continuously purifying the liquid fraction, thereby gradually reducing the content of nitrogen oxides in the liquid fraction, and then gradually increasing the purity of sulfur dioxide in the liquid fraction. The continuous purification of the liquid fraction in the distillation tower can improve the utilization rate of the distillation tower, so that the distillation of the regenerated rich gas can be achieved through a small number of distillation towers, thereby reducing the number of distillation towers.

[0007] In some embodiments, the flue gas low-temperature adsorption purification system also includes a low-temperature condenser, which has a cooling inlet and a cooling outlet. The cooling inlet is connected to the liquid outlet so that the liquid phase fraction enters the low-temperature condenser through the cooling inlet and is cooled by the low-temperature condenser, and the cooling outlet is connected to the second cooling liquid inlet so that the cooled liquid phase fraction enters the distillation tower through the second cooling liquid inlet.

[0008] In some embodiments, the low-temperature condenser has a first inlet for introducing a first heat exchange medium and a first outlet for discharging the first heat exchange medium, and the first heat exchange medium exchanges heat with the liquid fraction to cool the liquid fraction; and / or, the condenser-liquefier has a second inlet for introducing a second heat exchange medium and a second outlet for discharging the second heat exchange medium, and the second heat exchange medium in the condenser-liquefier exchanges heat with the gaseous fraction to condense the gaseous fraction.

[0009] In some embodiments, the flue gas low-temperature adsorption purification system also includes a supply pipeline and a delivery pipeline, the supply pipeline is connected to the first inlet and the second inlet to supply heat exchange medium to the low-temperature condenser and the condenser-liquefier, respectively, and the delivery pipeline is connected to the first outlet and the second outlet to transport the heat exchange medium discharged from the low-temperature condenser and the condenser-liquefier.

[0010] In some embodiments, the flue gas low-temperature adsorption purification system also includes a liquid collecting tank, which is connected to the condensate outlet to store the condensate discharged from the condenser-liquefier, and the liquid collecting tank is connected to the third coolant inlet so that the liquid collecting tank supplies condensate to the distillation tower.

[0011] In some embodiments, the regeneration tower further includes an upper carrier gas inlet, which is located at the upper part of the regeneration tower. The upper carrier gas inlet is connected to the flue gas outlet of the cooling tower, so that a portion of the low-temperature flue gas is passed through the upper carrier gas inlet as a carrier gas into the top space of the regeneration tower, so as to reduce the temperature of the top space of the regeneration tower and carry the regeneration gas generated in the regeneration tower to be discharged from the regeneration gas outlet. Alternatively, the upper carrier gas inlet is connected to the flue gas outlet of the adsorption tower, so that a portion of the adsorbed flue gas is passed through the upper carrier gas inlet as a carrier gas into the top space of the regeneration tower, so as to reduce the temperature of the top space of the regeneration tower and carry the regeneration gas generated in the regeneration tower to be discharged from the regeneration gas outlet.

[0012] In some embodiments, the regeneration tower further includes a carrier gas inlet, which is arranged at the lower part of the regeneration tower and is connected to the flue gas outlet of the adsorption tower, wherein a portion of the adsorbed flue gas discharged from the adsorption tower is passed into the bottom space of the regeneration tower through the carrier gas inlet as carrier gas, so as to reduce the temperature of the bottom space of the regeneration tower, and the regeneration gas generated in the regeneration tower is carried together with the upper carrier gas and discharged from the regeneration gas outlet.

[0013] In some embodiments, the flue gas low-temperature adsorption purification system also includes a boiler, which is connected to the cooling tower. The flue gas discharged from the boiler is supplied to the cooling tower for cooling. The condenser-liquefier also has a non-condensable gas outlet. The non-condensable gas flows out of the condenser-liquefier through the non-condensable gas outlet. The non-condensable gas outlet is connected to the boiler so that the non-condensable gas discharged from the non-condensable gas outlet can be passed into the boiler for re-reaction.

[0014] In some embodiments, the flue gas low-temperature adsorption purification system also includes a heat exchange device, which includes a first inlet, a first outlet, a flue gas inlet and a heat exchange outlet. The flue gas inlet is used to connect with the boiler so that the flue gas discharged from the boiler enters the heat exchange device, the first inlet is connected with the non-condensable gas outlet so that the non-condensable gas discharged from the non-condensable gas outlet enters the heat exchange device and cools the flue gas, the first outlet is connected with the boiler so that the non-condensable gas after heat exchange enters the boiler, and the heat exchange outlet is connected with the cooling tower so that the flue gas after heat exchange enters the cooling tower.

[0015] In some embodiments, the flue gas cryogenic adsorption purification system further comprises an air preheater communication between the non-condensable gas outlet and the boiler, so that the non-condensable gas discharged from the non-condensable gas outlet enters the boiler again after passing through the air preheater. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of a regenerative gas treatment system according to an embodiment of the present application.

[0017] REFERENCE NUMERALS

[0018] 100, flue gas cryogenic adsorption purification system; 1, rectifying column; 2, condensing liquefier; 3, low-temperature condenser; 4, liquid collection tank; 5, supply pipeline; 6, conveying pipeline; 7, cooling tower; 8, adsorption tower; 9, regeneration tower; 10, boiler;

[0019] 11, regenerative gas inlet; 12, gas phase fraction outlet; 13, cooling liquid first inlet; 14, cooling liquid third inlet; 15, liquid outlet; 16, cooling liquid second inlet;

[0020] 21, gas phase fraction inlet; 22, non-condensable gas outlet; 23, condensate outlet; 24, second inlet; 25, second outlet;

[0021] 31, cooling inlet; 32, cooling outlet; 33, first inlet; 34, first outlet;

[0022] 41, liquid inlet; 42, first liquid outlet; 43, second liquid outlet;

[0023] 71, flue gas outlet;

[0024] 81, adsorbent layer;

[0025] 91, regenerative gas outlet; 92, upper carrier gas inlet; 93, lower carrier gas inlet. DETAILED DESCRIPTION

[0026] Embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0027] A flue gas cryogenic adsorption purification system 100 according to an embodiment of the present application is described below in conjunction with the accompanying drawings.

[0028] As Figure 1As shown, the flue gas low-temperature adsorption purification system 100 of an embodiment of the present invention includes a cooling tower 7, an adsorption tower 8 and a regeneration tower 9 connected in sequence. The cooling tower 7 is used to cool the flue gas to low-temperature flue gas below zero degrees and supply it to the adsorption tower 8. The adsorbent layer 81 in the adsorption tower 8 is used to adsorb and purify the low-temperature flue gas into clean flue gas. The adsorption-saturated adsorbent in the adsorption tower 8 can be supplied to the regeneration tower 9 for regeneration to produce regenerated adsorbent and regenerated rich gas. The regenerated adsorbent can be supplied to the adsorption tower 8. The regeneration tower 9 has a regenerated rich gas outlet for discharging the regenerated rich gas.

[0029] The high-temperature flue gas is cooled to low-temperature flue gas in cooling tower 7. After exiting cooling tower 7, the low-temperature flue gas enters adsorption tower 8. Adsorbent layer 81 within adsorption tower 8 absorbs and purifies the low-temperature flue gas, converting it into clean flue gas. This clean flue gas meets emission standards and can be discharged directly or at a designated location. The saturated adsorbent layer 81 in adsorption tower 8 is fed to regeneration tower 9 for regeneration, producing regenerated adsorbent and regenerated rich gas. After regeneration, the adsorbent in adsorbent layer 81 is fed back to adsorption tower 8 for further adsorption regeneration of the low-temperature flue gas.

[0030] The adsorption tower 8 adsorbs the low-temperature flue gas to remove nitrogen oxides, sulfur dioxide, and other harmful components in the low-temperature flue gas, thereby producing clean flue gas that meets emission standards, thereby achieving purification of the low-temperature flue gas. The adsorbent layer 81 that is saturated with adsorption enters the regeneration tower 9 for regeneration, so that the adsorbent layer 81 can continue to adsorb the low-temperature flue gas, thereby achieving recycling of the adsorbent layer 81, thereby reducing the cost of purifying the flue gas. Moreover, the adsorption saturated adsorbent layer 81 entering the regeneration tower 9 can release nitrogen oxides, sulfur dioxide, and other harmful components in the adsorbent layer 81 to form regenerated rich gas, which is convenient for treating nitrogen oxides, sulfur dioxide, and other harmful components.

[0031] The flue gas low-temperature adsorption purification system 100 also includes a distillation tower 1 and a condenser-liquefier 2. The distillation tower 1 has a first coolant inlet 13, a second coolant inlet 16, a liquid outlet 15, and a third coolant inlet 14. The first coolant inlet 13 is used to supply coolant into the distillation tower 1. The distillation tower 1 is connected to the regeneration rich gas outlet, so that the regeneration rich gas discharged from the regeneration rich gas outlet enters the distillation tower 1 through the regeneration rich gas inlet, exchanges heat with the coolant, and undergoes distillation to produce a gaseous fraction and a liquid fraction. The liquid outlet 15 is connected to the second coolant inlet 16, so that the liquid fraction flows out of the distillation tower 1 through the liquid outlet 15 and flows into the distillation tower 1 through the second coolant inlet 16, thereby distilling the regeneration rich gas in the distillation tower 1 and releasing a portion of the nitrogen oxides in the liquid fraction.

[0032] The condenser-liquefier 2 has a gaseous fraction inlet 21 and a condensate outlet 23. The gaseous fraction inlet 21 is connected to the distillation tower 1 so that the gaseous fraction flowing out of the distillation tower 1 enters the condenser-liquefier 2 through the gaseous fraction inlet 21 to be condensed and produce non-condensable gas and condensate. The condensate outlet 23 is connected to the third coolant inlet 14 so that the condensate discharged from the condensate outlet 23 flows into the distillation tower 1 through the third coolant inlet 14 to utilize the condensate to perform low-temperature distillation on the regenerated rich gas.

[0033] It should be noted that the cooling liquid may be water or other solutions suitable for distillation and regeneration of rich gas.

[0034] The regenerated rich gas enters the distillation tower 1 for distillation to produce a gaseous fraction and a liquid fraction, so as to separate the nitrogen oxides and sulfur dioxide in the regenerated rich gas. Among them, the sulfur dioxide in the regenerated rich gas is mainly present in the liquid fraction, and the nitrogen oxides in the regenerated rich gas are mainly present in the gaseous fraction.

[0035] The liquid fraction exits the distillation tower 1 through the liquid outlet 15 and enters the distillation tower 1 through the second coolant inlet 16 to rectify the regenerated rich gas, replacing the coolant in rectifying the regenerated rich gas, thereby reducing the amount of coolant used. When the liquid fraction produced in the distillation tower 1 reaches a predetermined amount, the liquid fraction can completely replace the coolant in rectifying the regenerated rich gas. During the subsequent operation of the flue gas low-temperature adsorption purification system 100 according to the embodiment of the present invention, there is no need to add additional coolant to the distillation tower 1, thereby greatly reducing the amount of coolant used.

[0036] When the liquid fraction partially or completely replaces the coolant to rectify the regenerated rich gas, some of the nitrogen oxides in the liquid fraction are released as gas, thereby reducing the nitrogen oxide content in the liquid fraction and increasing the purity of sulfur dioxide in the liquid fraction. In other words, rectifying the regenerated rich gas by partially or completely replacing the coolant with the liquid fraction is equivalent to continuously purifying the liquid fraction, thereby gradually reducing the nitrogen oxide content in the liquid fraction and gradually increasing the purity of sulfur dioxide in the liquid fraction. Continuous purification of the liquid fraction within the rectifying tower 1 can improve the utilization rate of the rectifying tower 1, thereby enabling rectification of the regenerated rich gas to be achieved with fewer rectifying towers 1. For example, a single rectifying tower can be used to rectify the regenerated rich gas, thereby reducing the number of rectifying towers 1.

[0037] When the purity of sulfur dioxide in the liquid fraction in the distillation tower 1 meets the requirements, the liquid fraction can be discharged so as to further process the sulfur dioxide in the liquid fraction.

[0038] The gaseous fraction is condensed in the condenser-liquefier 2. The sulfur dioxide in the gaseous fraction is condensed and liquefied and present in the condensate, thereby separating the nitrogen oxides and sulfur dioxide in the gaseous fraction. The condensate flows into the distillation column 1 through the third coolant inlet 14 to distill the regenerated rich gas, further reducing the amount of coolant used.

[0039] When the condensate is distilling the regenerated rich gas, part of the nitrogen oxides in the condensate are released in the form of gas, thereby increasing the purity of sulfur dioxide in the condensate, and then maintaining a high level of sulfur dioxide purity in the liquid fraction after the condensate is merged into the liquid fraction.

[0040] like Figure 1 As shown, optionally, the gaseous fraction outlet 12 is communicated with the gaseous fraction inlet 21 , so that the gaseous fraction can leave the distillation tower 1 through the gaseous fraction outlet 12 and enter the condenser liquefier 2 through the gaseous fraction inlet 21 .

[0041] like Figure 1 As shown, in some embodiments, the flue gas low-temperature adsorption purification system 100 further includes a low-temperature condenser 3, which has a cooling inlet 31 and a cooling outlet 32. The cooling inlet 31 is connected to the liquid outlet 15 so that the liquid phase fraction enters the low-temperature condenser 3 through the cooling inlet 31 and is cooled by the low-temperature condenser 3. The cooling outlet 32 ​​is connected to the second cooling liquid inlet 16 so that the cooled liquid phase fraction enters the distillation tower 1 through the second cooling liquid inlet 16.

[0042] The liquid fraction discharged from the liquid outlet 15 is cooled by the low-temperature condenser 3 so as to improve the distillation effect of the liquid fraction entering the distillation tower 1 .

[0043] like Figure 1 As shown, in some embodiments, the low-temperature condenser 3 has a first inlet 33 for introducing a first heat exchange medium and a first outlet 34 for discharging the first heat exchange medium. The first heat exchange medium exchanges heat with the liquid fraction to cool the liquid fraction, so that the first heat exchange medium can enter the low-temperature condenser 3 through the first inlet 33 and exchange heat with the liquid fraction. The first heat exchange medium after heat exchange leaves the low-temperature condenser 3 through the first outlet 34.

[0044] Optionally, the first heat exchange medium is calcium chloride solution or ethylene glycol solution.

[0045] Optionally, the temperature of the first heat exchange medium is less than or equal to 0 degrees Celsius to increase the heat exchange effect between the first heat exchange medium and the liquid fraction.

[0046] Preferably, the temperature of the first heat exchange medium is less than or equal to 0 degrees Celsius and greater than or equal to -13 degrees Celsius to avoid the first heat exchange medium from solidifying at low temperature.

[0047] like Figure 1 As shown, in some embodiments, the condenser-liquefier 2 has a second inlet 24 for introducing a second heat exchange medium and a second outlet 25 for discharging the second heat exchange medium. The second heat exchange medium in the condenser-liquefier 2 exchanges heat with the gaseous fraction to condense the gaseous fraction, so that the second heat exchange medium can enter the condenser-liquefier 2 through the second inlet 24 to exchange heat with the gaseous fraction. The second heat exchange medium after heat exchange leaves the low-temperature condenser through the second outlet 25.

[0048] Optionally, the second heat exchange medium is a calcium chloride solution or an ethylene glycol solution.

[0049] Optionally, the temperature of the second heat exchange medium is less than or equal to 0 degrees Celsius to increase the heat exchange effect between the second heat exchange medium and the liquid fraction.

[0050] Preferably, the temperature of the second heat exchange medium is less than or equal to 0 degrees Celsius and greater than or equal to -13 degrees Celsius to prevent the second heat exchange medium from solidifying at low temperature.

[0051] Optionally, the first heat exchange medium and the second heat exchange medium may be the same or different.

[0052] like Figure 1 As shown, in some embodiments, the flue gas low-temperature adsorption purification system 100 further includes a supply pipeline 5 and a delivery pipeline 6, the supply pipeline 5 is connected to the first inlet 33 and the second inlet 24 to supply heat exchange medium to the low-temperature condenser 3 and the condenser-liquefier 2 respectively, and the delivery pipeline 6 is connected to the first outlet 34 and the second outlet 25 to transport the heat exchange medium discharged from the low-temperature condenser 3 and the condenser-liquefier 2.

[0053] The supply pipeline 5 can continuously supply the first heat exchange medium to the low-temperature condenser 3 to improve the condensation effect of the low-temperature condenser 3. The delivery pipeline 6 can deliver the first heat exchange medium after heat exchange to avoid the first heat exchange medium after heat exchange from being retained in the low-temperature condenser 3, thereby avoiding the first heat exchange medium after heat exchange from reducing the condensation effect of the low-temperature condenser 3, so as to further improve the condensation effect of the low-temperature condenser 3.

[0054] The supply pipeline 5 can continuously supply the second heat exchange medium to the condenser-liquefier 2 to improve the condensation and liquefaction effect of the condenser-liquefier 2. The delivery pipeline 6 can deliver the second heat exchange medium after heat exchange to avoid the second heat exchange medium after heat exchange from being retained in the condenser-liquefier 2, thereby avoiding the second heat exchange medium after heat exchange from reducing the condensation and liquefaction effect of the condenser-liquefier 2, so as to further improve the condensation and liquefaction effect of the condenser-liquefier 2.

[0055] Optionally, multiple supply pipelines 5 are provided, with some supplying the first heat exchange medium to the low-temperature condenser 3, and others supplying the second heat exchange medium to the condenser-liquefier 2. Multiple delivery pipelines 6 are provided, with some delivering the first heat exchange medium from the low-temperature condenser 3, and others delivering the second heat exchange medium from the condenser-liquefier 2. This allows the first heat exchange medium to be supplied to the low-temperature condenser 3 and the second heat exchange medium to be supplied to the condenser-liquefier 2 via the supply pipelines 5, and allows the first heat exchange medium to be delivered from the low-temperature condenser 3 and the second heat exchange medium to be delivered from the condenser-liquefier 2 via the delivery pipelines 6.

[0056] like Figure 1 As shown, preferably, the first heat exchange medium and the second heat exchange medium are the same, the supply pipeline 5 supplies the first heat exchange medium (the second heat exchange medium) to the low-temperature condenser 3 and the condenser-liquefier 2, and the delivery pipeline 6 delivers the first heat exchange medium (the second heat exchange medium) from the low-temperature condenser 3. By supplying the first heat exchange medium (the second heat exchange medium) to the low-temperature condenser 3 and the condenser-liquefier 2 through fewer supply pipelines 5 and delivering the first heat exchange medium (the second heat exchange medium) from the low-temperature condenser 3 and the condenser-liquefier 2 through fewer delivery pipelines 6, the number of components in the low-temperature flue gas adsorption purification system 100 according to the embodiment of the present invention can be reduced, and the complexity of the low-temperature flue gas adsorption purification system 100 according to the embodiment of the present invention can be reduced.

[0057] like Figure 1 As shown, in some embodiments, the flue gas low-temperature adsorption purification system 100 further includes a liquid collecting tank 4, which is connected to the condensate outlet 23 to store the condensate discharged from the condenser liquefier 2, and the liquid collecting tank 4 is connected to the third coolant inlet 14 so that the liquid collecting tank 4 supplies the condensate to the distillation tower 1.

[0058] The condensate is stored in the liquid collecting tank 4 so that the condensate can be supplied to the distillation tower 1 according to the demand of the distillation tower 1 .

[0059] like Figure 1 As shown, optionally, the liquid inlet 41 of the liquid collecting tank 4 is connected to the condensate outlet 23, so that the condensate can enter the liquid collecting tank 4 through the liquid inlet. The first liquid outlet 42 of the liquid collecting tank 4 is connected to the third coolant inlet 14 so that the liquid collecting tank 4 supplies the condensate to the distillation column 1 through the first liquid outlet 42.

[0060] like Figure 1 As shown, further, the liquid collecting tank 4 is provided with a second liquid outlet 43 so as to directly discharge the condensate stored in the liquid collecting tank 4 .

[0061] In the related art, during the desorption and regeneration process of the adsorbent in the regeneration tower, a large amount of nitrogen needs to be introduced into the regeneration tower to carry the regenerated rich gas out of the regeneration tower. Since nitrogen needs to be introduced as a carrier gas, the investment and operation costs are high.

[0062] For this reason, Figure 1 As shown, in some embodiments, the regeneration tower 9 also includes an upper carrier gas inlet 92, which is arranged at the upper part of the regeneration tower 9. The upper carrier gas inlet 92 is connected to the flue gas outlet 71 of the cooling tower 7, so that a part of the low-temperature flue gas is passed into the top space of the regeneration tower 9 through the upper carrier gas inlet 92 as a carrier gas, so as to reduce the temperature of the top space of the regeneration tower 9 and carry the regeneration gas generated in the regeneration tower 9 to be discharged from the regeneration gas outlet 91, or, the upper carrier gas inlet 92 is connected to the flue gas outlet of the adsorption tower 8, so that a part of the adsorbed flue gas is passed into the top space of the regeneration tower 9 through the upper carrier gas inlet 92 as a carrier gas, so as to reduce the temperature of the top space of the regeneration tower 9 and carry the regeneration gas generated in the regeneration tower 9 to be discharged from the regeneration gas outlet 91.

[0063] In an embodiment of the present invention, a portion of low-temperature flue gas is introduced into the top space of the regeneration tower 9 as an upper carrier gas. On the one hand, the temperature of the top of the regeneration tower 9 can be conveniently controlled to avoid the generation of water vapor and condensed water at the top of the regeneration tower 9 due to the temperature increase of the preheating section and the regeneration section of the regeneration tower 9. It can also solve the problems of blockage of the material drop at the top of the regeneration tower 9, blockage of the adsorbent channel, and false alarm of the material level at the top of the regeneration tower 9 caused by the mixing of condensed water and adsorbent dust.

[0064] On the other hand, the low-temperature flue gas plays the same role as an inert gas such as nitrogen, so nitrogen can be omitted as a carrier gas or at least the amount of nitrogen used can be reduced. The regenerated rich gas can be quickly discharged from the regeneration tower 9, and the water vapor generated by heating the adsorbent in the regeneration tower 9 can be discharged at the same time. The oxygen concentration in the regeneration tower 9 can also be reduced, thereby reducing the risk of combustion of the adsorbent in the regeneration tower 9.

[0065] On the other hand, since a large amount of water vapor and condensed water is avoided from being generated in the regeneration tower and a small amount of water vapor and condensed water can be quickly taken out of the regeneration tower, corrosion of the regeneration tower is avoided or at least alleviated.

[0066] like Figure 1 As shown, optionally, the regeneration gas inlet 11 is connected to the regeneration gas outlet 91 , so that the regeneration rich gas can leave the regeneration tower 9 through the regeneration gas outlet 91 and enter the distillation tower 1 through the regeneration gas inlet 11 .

[0067] In some embodiments, the regeneration tower 9 further includes a downgas inlet 93, which is located at the lower portion of the regeneration tower 9 and is connected to the flue gas outlet of the adsorption tower 8. A portion of the adsorbed flue gas discharged from the adsorption tower 8 is passed into the bottom space of the regeneration tower 9 through the downgas inlet 93 as downgas, to reduce the temperature of the bottom space of the regeneration tower 9, and is carried together with the upper carrier gas to carry the regenerated gas generated in the regeneration tower 9 and discharged from the regeneration gas outlet 91.

[0068] In the embodiment of the present invention, upper and lower carrier gases are introduced through the upper and lower carrier gas inlets of the regeneration tower 9, respectively, to ensure that the regenerated rich gas in the regeneration tower 9 is completely discharged. Introducing the lower carrier gas to the bottom of the regeneration tower 9 further improves the cooling effect of the cooling section of the regeneration tower.

[0069] Moreover, by using a portion of the clean flue gas discharged from the adsorption tower 8 as the carrier gas, the clean flue gas is reused to reduce costs. Moreover, the use of clean flue gas will not pollute the adsorbent in the cooling section of the regeneration tower 9.

[0070] It should be noted that since the adsorbent reaching the cooling section of the regeneration tower 9 is the desorbed adsorbent, passing clean flue gas into the cooling section can prevent the adsorbent from being contaminated. However, the low-temperature flue gas after spray cooling has not been adsorbed and purified by the adsorption tower 8, so the low-temperature flue gas discharged from the cooling tower 7 cannot be passed into the cooling section.

[0071] In some embodiments, the downgas inlet 93 is provided on the side wall of the lower portion of the regeneration tower 9 , the adsorbent outlet of the regeneration tower 9 is connected to the adsorbent feed port of the adsorption tower 8 , and the adsorbent outlet is located on the bottom wall of the regeneration tower 9 .

[0072] like Figure 1 As shown, in some embodiments, the flue gas low-temperature adsorption purification system 100 also includes a boiler 10, which is connected to a cooling tower 7. The flue gas discharged from the boiler 10 is supplied to the cooling tower 7 for cooling. The condenser-liquefier 2 also has a non-condensable gas outlet, and the non-condensable gas flows out of the condenser-liquefier 2 through the non-condensable gas outlet. The non-condensable gas outlet 22 is connected to the boiler 10 so that the non-condensable gas discharged from the non-condensable gas outlet is passed into the boiler 10 for a re-melting reaction to achieve the treatment of the non-condensable gas.

[0073] In some embodiments, the flue gas low-temperature adsorption purification system 100 also includes a heat exchange device, which includes a first inlet, a first outlet, a flue gas inlet and a heat exchange outlet. The flue gas inlet is used to connect with the boiler 10 so that the flue gas discharged from the boiler 10 enters the heat exchange device. The first inlet is connected with the non-condensable gas outlet so that the non-condensable gas discharged from the non-condensable gas outlet enters the heat exchange device and cools the flue gas. The first outlet is connected with the boiler 10 so that the non-condensable gas after heat exchange enters the boiler 10. The heat exchange outlet is connected with the cooling tower 7 so that the flue gas after heat exchange enters the cooling tower 7.

[0074] Since the temperature of the non-condensable gas is relatively low, the heat exchange device is used to exchange heat between the non-condensable gas and the high-temperature flue gas, thereby lowering the temperature of the high-temperature flue gas and reducing the cooling capacity loss of the cooling tower 7 in cooling the high-temperature flue gas.

[0075] The heat exchange device allows the non-condensable gas and the high-temperature flue gas to exchange heat, thereby increasing the temperature of the non-condensable gas, thereby reducing the heat loss of the boiler 10 after the non-condensable gas enters the boiler 10 .

[0076] In some embodiments, the flue gas low-temperature adsorption purification system 100 further includes an air preheater connected to the non-condensable gas outlet and the boiler 10 so that the non-condensable gas discharged from the non-condensable gas outlet passes through the air preheater and then enters the boiler 10.

[0077] The non-condensable gas is preheated by the air preheater, thereby further reducing the heat loss of the boiler 10 after the non-condensable gas enters the boiler 10 .

[0078] In the description of the present invention, 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 to 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 invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0079] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0080] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0081] In the present invention, 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 that the first and second features are in indirect contact through an intermediary. 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.

[0082] In the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," 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 invention. In this specification, the schematic representations 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 appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0083] 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 invention. 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 invention.

Claims

1. A flue gas low-temperature adsorption purification system, characterized in that: The system comprises a cooling tower, an adsorption tower and a regeneration tower connected in sequence. The cooling tower is used to cool the flue gas to low-temperature flue gas below zero degrees and supply it to the adsorption tower. The adsorbent layer in the adsorption tower is used to adsorb and purify the low-temperature flue gas into clean flue gas. The adsorption saturated adsorbent in the adsorption tower can be supplied to the regeneration tower to regenerate and produce regenerated adsorbent and regenerated rich gas. The regenerated adsorbent can be supplied to the adsorption tower. The regeneration tower has a regeneration rich gas outlet for discharging the regenerated rich gas. The flue gas low-temperature adsorption purification system also includes: a distillation tower having a first cooling liquid inlet, a second cooling liquid inlet, a liquid outlet, and a third cooling liquid inlet, wherein the first cooling liquid inlet is used to supply cooling liquid into the distillation tower, the distillation tower is communicated with the regeneration rich gas outlet, so that the regeneration rich gas discharged from the regeneration rich gas outlet enters the distillation tower through the regeneration rich gas inlet and exchanges heat with the cooling liquid for distillation to produce a gaseous fraction and a liquid fraction, and the liquid outlet is communicated with the second cooling liquid inlet, so that the liquid fraction flows out of the distillation tower through the liquid outlet and flows into the distillation tower through the second cooling liquid inlet, thereby rectifying the regeneration rich gas in the distillation tower and releasing a portion of nitrogen oxides in the liquid fraction; A condenser-liquefier having a gaseous fraction inlet and a condensate outlet, wherein the gaseous fraction inlet is connected to the distillation tower so that the gaseous fraction flowing out of the distillation tower enters the condenser-liquefier through the gaseous fraction inlet for condensation and produces non-condensable gas and condensate, and the condensate outlet is connected to the third coolant inlet so that the condensate discharged from the condensate outlet flows into the distillation tower through the third coolant inlet to utilize the condensate to perform low-temperature distillation on the regenerated rich gas.

2. The flue gas low-temperature adsorption purification system according to claim 1, characterized in that: It also includes a low-temperature condenser, which has a cooling inlet and a cooling outlet. The cooling inlet is connected to the liquid outlet so that the liquid fraction enters the low-temperature condenser through the cooling inlet and is cooled by the low-temperature condenser. The cooling outlet is connected to the second cooling liquid inlet so that the cooled liquid fraction enters the distillation tower through the second cooling liquid inlet.

3. The flue gas low-temperature adsorption purification system according to claim 2, characterized in that: The low-temperature condenser has a first inlet for introducing a first heat exchange medium and a first outlet for discharging the first heat exchange medium, wherein the first heat exchange medium exchanges heat with the liquid fraction to cool the liquid fraction; and / or, The condenser-liquefier has a second inlet for introducing a second heat exchange medium and a second outlet for discharging the second heat exchange medium. The second heat exchange medium in the condenser-liquefier exchanges heat with the gas phase fraction to condense the gas phase fraction.

4. The flue gas low-temperature adsorption purification system according to claim 3, characterized in that: It also includes a supply pipeline and a delivery pipeline, the supply pipeline is connected to the first inlet and the second inlet to supply heat exchange medium to the low-temperature condenser and the condenser-liquefier respectively, and the delivery pipeline is connected to the first outlet and the second outlet to deliver the heat exchange medium discharged from the low-temperature condenser and the condenser-liquefier.

5. The flue gas low-temperature adsorption purification system according to claim 1, characterized in that: The device further comprises a liquid collecting tank, which is in communication with the condensate outlet to store the condensate discharged from the condenser-liquefier, and is in communication with the third coolant inlet so that the liquid collecting tank supplies the condensate to the distillation column.

6. The flue gas low-temperature adsorption purification system according to claim 1, characterized in that: The regeneration tower further includes an upper carrier gas inlet, which is provided at the upper portion of the regeneration tower and is communicated with the flue gas outlet of the cooling tower, so that a portion of the low-temperature flue gas is passed through the upper carrier gas inlet as an upper carrier gas into the top space of the regeneration tower to reduce the temperature of the top space of the regeneration tower and carry the regeneration rich gas generated in the regeneration tower to be discharged from the regeneration rich gas outlet, or, The upper carrier gas inlet is connected to the flue gas outlet of the adsorption tower, so that a portion of the adsorbed flue gas is passed into the top space of the regeneration tower through the upper carrier gas inlet as the upper carrier gas, so as to reduce the temperature of the top space of the regeneration tower and carry the regeneration rich gas generated in the regeneration tower to be discharged from the regeneration rich gas outlet.

7. The flue gas low-temperature adsorption purification system according to claim 6, characterized in that: The regeneration tower also includes a carrier gas inlet, which is arranged at the lower part of the regeneration tower and is connected to the flue gas outlet of the adsorption tower, wherein a portion of the adsorbed flue gas discharged from the adsorption tower is passed into the bottom space of the regeneration tower through the carrier gas inlet as carrier gas, so as to reduce the temperature of the bottom space of the regeneration tower, and the regeneration rich gas generated in the regeneration tower is carried together with the upper carrier gas and discharged from the regeneration rich gas outlet.

8. The flue gas low-temperature adsorption purification system according to any one of claims 1 to 6, characterized in that: It also includes a boiler, which is connected to the cooling tower. The flue gas discharged from the boiler is supplied to the cooling tower for cooling. The condenser-liquefier also has a non-condensable gas outlet. The non-condensable gas flows out of the condenser-liquefier through the non-condensable gas outlet. The non-condensable gas outlet is connected to the boiler so that the non-condensable gas discharged from the non-condensable gas outlet can be passed into the boiler for re-melting reaction.

9. The flue gas low-temperature adsorption purification system according to claim 8, characterized in that: It also includes a heat exchange device, which includes a first inlet, a first outlet, a flue gas inlet and a heat exchange outlet. The flue gas inlet is used to be connected to the boiler so that the flue gas discharged from the boiler enters the heat exchange device. The first inlet is connected to the non-condensable gas outlet so that the non-condensable gas discharged from the non-condensable gas outlet enters the heat exchange device and cools the flue gas. The first outlet is connected to the boiler so that the non-condensable gas after heat exchange enters the boiler. The heat exchange outlet is connected to the cooling tower so that the flue gas after heat exchange enters the cooling tower.

10. The flue gas low-temperature adsorption purification system according to claim 8, characterized in that: It also includes an air preheater, which is connected to the non-condensable gas outlet and the boiler, so that the non-condensable gas discharged from the non-condensable gas outlet passes through the air preheater and then enters the boiler.

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