Flue gas purification and resource recycling system and method based on low-temperature flue gas adsorption and regeneration

Abstract

A flue gas purification and resource recycling system and method having low-temperature flue gas adsorption and regeneration. The flue gas purification and resource recycling system comprises a low-temperature flue gas adsorption and regeneration system (1), an oxidation tower (2), a reactor (3), and a purification system (4). The low-temperature flue gas adsorption and regeneration system (1) comprises a cooling apparatus (11), an adsorption apparatus (12), and a regeneration apparatus (13) which are arranged in sequence, so as to generate regeneration gas containing nitrogen and sulfur. The oxidation tower (2) is internally provided with a water spraying apparatus (26) so that the regeneration gas containing nitrogen and sulfur discharged from the regeneration apparatus (13) is oxidized by ozone in the oxidation tower (2) and then sprayed by the water spraying apparatus (26) to obtain an acid solution. The reactor (3) is provided with an ammonia water inlet (31), and the reactor (3) is connected to an acid solution outlet (23) and a residual gas outlet (24) of the oxidation tower (2) so as to enable reaction to obtain an ammonia sulfate nitrate solution. The purification system (4) is used for purifying the ammonia sulfate nitrate solution discharged from the reactor (3) to obtain an ammonia sulfate nitrate product. The flue gas purification and resource recycling system has the advantages of simplified process steps and low production costs.

Description

Flue gas purification resource recycling system and method based on low-temperature flue gas adsorption regeneration

[0001] Cross-reference to Related Applications

[0002] The present disclosure is based on and claims priority to Chinese Patent Application No. 202410855786.9, filed on June 28, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the field of flue gas purification, in particular to a flue gas purification resource recycling system and a flue gas purification resource recycling method based on low-temperature flue gas adsorption regeneration. BACKGROUND

[0004] The COAP technology is a comprehensive flue gas pollutant treatment technology. Based on the principle of low-temperature flue gas adsorption, the flue gas to be purified is cooled to a low temperature in the subzero temperature zone, and then enters a low-temperature adsorption tower for adsorption and purification by an adsorbent. The NOx, SOx, Hg and other pollutants in the flue gas can be deeply adsorbed and removed at low temperature. x The saturated adsorbent generates a large amount of nitrogen and sulfur-containing regeneration gas after regeneration. In related technologies, in order to recycle and utilize resources, the nitrogen and sulfur-containing regeneration gas is first separated into sulfur-containing gas and nitrogen-containing gas, and then the two types of gas are respectively prepared into corresponding products through related processes. In related technologies, the separation of sulfur and nitrogen gas and the preparation of corresponding products through multiple processes are required, which has the problems of high cost and complex process. SUMMARY

[0005] The present disclosure aims to at least partially solve one of the technical problems in the related art. To this end, the present disclosure proposes a flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration. The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration has the advantages of simplified process steps and low production cost.

[0006] The present disclosure also proposes a flue gas purification resource recycling method based on low-temperature flue gas adsorption regeneration.

[0007] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the present disclosure comprises a low-temperature flue gas adsorption regeneration system, an oxidation tower, a reactor and a purification system.

[0008] The low-temperature flue gas adsorption regeneration system comprises a cooling device, an adsorption device and a regeneration device, the cooling device is used for cooling the flue gas into low-temperature flue gas with zero temperature, the adsorption device is used for adsorbing and purifying the low-temperature flue gas into clean flue gas by an adsorbent, and the regeneration device is used for regenerating the adsorbent saturated with adsorption and generating nitrogen-sulfur-containing regeneration gas; the oxidation tower is provided with a water spraying device, the oxidation tower has a nitrogen-sulfur-containing regeneration gas inlet, an ozone inlet for supplying ozone into the oxidation tower, an acid liquid outlet for discharging acid liquid in the oxidation tower and a residual gas outlet for discharging residual gas in the oxidation tower, the nitrogen-sulfur-containing regeneration gas inlet of the oxidation tower is communicated with the nitrogen-sulfur-containing regeneration gas outlet of the regeneration device, the nitrogen-sulfur-containing regeneration gas discharged from the regeneration device is ozone-oxidized regeneration gas after being oxidized by ozone in the oxidation tower, and the ozone-oxidized regeneration gas is sprayed by the water spraying device to obtain acid liquid; the reactor has an ammonia water inlet for supplying ammonia water into the reactor, the reactor is connected with the acid liquid outlet and the residual gas outlet of the oxidation tower, the acid liquid and the residual gas discharged from the oxidation tower enter the reactor and react with the ammonia water supplied into the reactor through the ammonia water inlet to obtain nitrosulfur ammonia solution in the reactor; the purification system is connected with the reactor and is used for purifying the nitrosulfur ammonia solution discharged from the reactor to obtain nitrosulfur ammonia product.

[0009] Optionally, the oxidation tower further comprises an acid liquid concentration pipeline, the oxidation tower further has an acid liquid circulation inlet arranged at an upper portion thereof, the acid liquid outlet is arranged at a bottom portion of the oxidation tower, one end of the acid liquid concentration pipeline is communicated with the acid liquid outlet, the other end of the acid liquid concentration pipeline is communicated with the acid liquid circulation inlet, and the acid liquid concentration pipeline is switchably communicated with the reactor.

[0010] Optionally, the flue gas purification and resource recycling system based on low-temperature flue gas adsorption regeneration further comprises an ozone destroyer arranged between the residual gas outlet of the oxidation tower and the reactor and used for removing ozone in the residual gas discharged from the oxidation tower.

[0011] Optionally, the residual gas outlet is arranged at a top portion of the oxidation tower.

[0012] Optionally, the flue gas purification and resource recycling system based on low-temperature flue gas adsorption regeneration further comprises a gas distributor arranged in the oxidation tower and used for uniformly dispersing the regeneration gas in the oxidation tower.

[0013] Optionally, the flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration further comprises an ammonium nitrate concentration pipeline, the reactor further has an ammonium nitrate liquid outlet and an ammonium nitrate liquid circulation port, the ammonium nitrate concentration pipeline is connected to the ammonium nitrate liquid outlet and the ammonium nitrate liquid circulation port, and the ammonium nitrate liquid outlet is switchably connected to the purification system and the ammonium nitrate liquid circulation port.

[0014] Optionally, the purification system comprises a flash separator, a neutralization washing tower, a stirring mixing device, a flash tank and an evaporator, a gas phase outlet of the flash separator is connected to a gas phase inlet of the neutralization washing tower through a pipeline, a liquid phase outlet of the flash separator is connected to a liquid phase inlet of the stirring mixing device through a pipeline, a gas phase outlet of the neutralization washing tower is connected to a gas phase inlet of the stirring mixing device through a pipeline, a discharge port of the stirring mixing device is connected to a feed port of the flash tank through a pipeline, a discharge port of the flash tank is connected to a feed port of the evaporator through a pipeline, a steam outlet of the neutralization washing tower is connected to a steam inlet of the evaporator through a pipeline, and a discharge port of the evaporator is connected to a filter pressing device.

[0015] Optionally, the nitrogen-containing sulfur regeneration gas comprises the following components by volume: SO2 28-30%, NO x 4.8-5.2%, N2 42-44%, CO2 4-6%, H2O 19-21%;

[0016] Optionally, the ozone oxidation regeneration gas comprises the following components by volume: SO2 30-32%, N2 43-45%, CO2 3-4%, H2O 19-21%.

[0017] The flue gas purification resource recycling method based on low-temperature flue gas adsorption regeneration provided by the present disclosure comprises the following steps:

[0018] Cooling the flue gas by a cooling device to obtain low-temperature flue gas at subzero temperature;

[0019] Passing the low-temperature flue gas into an adsorption device to obtain purified flue gas and saturated adsorbent;

[0020] Regenerating the saturated adsorbent to obtain regenerated adsorbent and nitrogen-containing sulfur regeneration gas;

[0021] Ozone-oxidizing the nitrogen-containing sulfur regeneration gas in an oxidation tower and spraying water to obtain acid liquid;

[0022] Passing ammonia water, the acid liquid in the oxidation tower and residual gas into a reactor to react with the ammonia water to obtain a nitrosulfur ammonia solution;

[0023] Sequentially performing solid-liquid separation and drying on the nitrosulfur ammonia solution to obtain a nitrosulfur ammonia product.

[0024] Optionally, the nitrogen-sulfur-containing regeneration gas comprises the following components by volume: SO2 28-30%, NO x 4.8-5.2%, N2 42-44%, CO2 4-6%, H2O 19-21%.

[0025] Optionally, the ozone oxidation regeneration gas comprises the following components by volume: SO2 30-32%, N2 43-45%, CO2 3-4%, H2O 19-21%.

[0026] The beneficial effects of the present disclosure are:

[0027] (1) The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the present disclosure can simultaneously pretreat the nitrogen-containing gas and sulfur-containing gas in the nitrogen-sulfur-containing regeneration gas by sequentially passing the nitrogen-sulfur-containing regeneration gas produced by the low-temperature flue gas adsorption regeneration system through the oxidation tower, the reactor, and the purification system to obtain the nitro-sulfur-ammonium product. For example, NO x The generated NO2 can react with water to generate an acid solution, and SO2 is also converted into SO3, which is dissolved in water to generate an acid solution. NO x and SO2 do not need to be separated and then treated separately, i.e., sulfur and nitrogen gas separation is not required. Furthermore, the acid solution is reacted with the lye (ammonia water) in the reactor to enable the reaction with the ammonia water, and the nitro-sulfur-ammonium product is generated through the purification system, which can produce nitro-sulfur-ammonium fertilizer. Not only is resource recycling achieved, but the process steps are also simplified, and the cost of the entire process is further reduced. In addition, the nitrogen-sulfur-containing regeneration gas is converted into a gas with as little pollution as possible in the entire process, and there is no secondary gas pollution in the production of the nitro-sulfur-ammonium product.

[0028] Therefore, the flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the present disclosure has the advantages of simplified process steps and low production cost.

[0029] (2) By providing an acid solution concentration pipeline, the obtained acid solution can be concentrated, and the obtained acid solution can be recycled multiple times according to the yield of the nitrogen-sulfur-containing regeneration gas to obtain high-concentration acid solution, which is conducive to reducing the cost of drying in the purification system. Therefore, it has the advantage of further reducing production costs.

[0030] (3) A gas distributor is provided in the oxidation tower to uniformly disperse the regeneration gas in the oxidation tower. Therefore, it helps to uniformly classify the remaining gas and ozone introduced into the oxidation tower, improving the contact effectiveness between the ozone and the remaining gas. Therefore, it has the advantage of high treatment efficiency of the nitrogen-sulfur-containing regeneration gas.

[0031] (4) The obtained nitrosulfuramino solution can be concentrated through the set ammonium nitrate concentration pipeline. The obtained nitrosulfuramino solution can be recycled multiple times according to the concentration of the nitrosulfuramino solution, so as to obtain a high-concentration nitrosulfuramino solution, thereby facilitating reduction of the cost of drying in the purification system. Thus, the production cost is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 is a structural schematic diagram of a flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration according to an embodiment of the present disclosure.

[0033] Fig. 2 is a flowchart of a process of a flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration according to an embodiment of the present disclosure.

[0034] Reference signs: low-temperature flue gas adsorption regeneration system 1; cooling device 11; adsorption device 12; regeneration device 13; oxidation tower 2; ozone inlet 21; nitrogen-sulfur-containing regeneration gas inlet 22; acid liquid outlet 23; excess gas outlet 24; acid liquid concentration pipeline 25; water spraying device 26; reactor 3; ammonia water inlet 31; ammonium nitrate liquid outlet 32; ammonium nitrate liquid circulation port 33; ammonium nitrate concentration pipeline 34; purification system 4; flash separator 41; neutralization washing tower 42; stirring and mixing device 43; flash tank 44; evaporator 45; ozone destroyer 5. DETAILED DESCRIPTION

[0035] The embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present disclosure, and cannot be understood as a limitation of the present disclosure.

[0036] The flue gas purification resource recycling system and method based on low-temperature flue gas adsorption regeneration according to an embodiment of the present disclosure are described below with reference to Figs. 1-2.

[0037] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration according to an embodiment of the present disclosure comprises a low-temperature flue gas adsorption regeneration system 1, an oxidation tower 2, a reactor 3, and a purification system 4.

[0038] The low-temperature flue gas adsorption regeneration system 1 comprises a cooling device 11, an adsorption device 12, and a regeneration device 13. The cooling device 11 is used to cool the flue gas into low-temperature flue gas at zero temperature. The adsorption device 12 is used to purify the low-temperature flue gas into clean flue gas by adsorption. The regeneration device 13 is used to regenerate the adsorbent saturated with adsorption and generate nitrogen-sulfur-containing regeneration gas.

[0039] The oxidation tower 2 is provided with a water spraying device 26, and the oxidation tower 2 has a nitrogen-sulfur-containing regenerated gas inlet 22, an ozone inlet 21 for supplying ozone into the oxidation tower 2, an acid liquid outlet 23 for discharging acid liquid in the oxidation tower 2, and a residual gas outlet 24 for discharging residual gas in the oxidation tower 2. The nitrogen-sulfur-containing regenerated gas inlet 22 of the oxidation tower 2 is communicated with the nitrogen-sulfur-containing regenerated gas outlet of the regeneration device 13. The nitrogen-sulfur-containing regenerated gas discharged from the regeneration device 13 is oxidized by ozone in the oxidation tower 2 to become ozone-oxidized regenerated gas, and the ozone-oxidized regenerated gas is sprayed by the water spraying device 26 to obtain the acid liquid.

[0040] The reactor 3 has an aqueous ammonia inlet 31 for supplying aqueous ammonia into the reactor 3. The reactor 3 is connected with the acid liquid outlet 23 and the residual gas outlet 24 of the oxidation tower 2. The acid liquid and the residual gas discharged from the oxidation tower 2 enter the reactor 3, and react with the aqueous ammonia supplied into the reactor 3 through the aqueous ammonia inlet 31 in the reactor 3 to obtain a nitrosulfurammonia solution.

[0041] The purification system 4 is connected with the reactor 3, and is used for purifying the nitrosulfurammonia solution discharged from the reactor 3 to obtain a nitrosulfurammonia product.

[0042] The low-temperature flue gas adsorption regeneration-based flue gas purification resource recycling system of the embodiment of the present disclosure can obtain the nitrosulfurammonia product by sequentially passing the nitrogen-sulfur-containing regenerated gas produced by the low-temperature flue gas adsorption regeneration system 1 through the oxidation tower 2, the reactor 3 and the purification system 4, and can simultaneously pretreat the nitrogen-containing gas and the sulfur-containing gas in the nitrogen-sulfur-containing regenerated gas. For example, NO x generates NO2, and dissolves in water to generate acid liquid. SO2 is also converted into SO3 accordingly, and dissolves in water to generate acid liquid. The NO x x and SO2 do not need to be separated and then treated separately, that is, the nitrogen and sulfur gases do not need to be separated. Furthermore, the acid liquid is reacted with the alkaline solution (aqueous ammonia) in the reactor 3, and the acid liquid and the aqueous ammonia are reacted to pass through the purification system 4 to generate the nitrosulfurammonia product, so that the nitrosulfurammonia fertilizer can be prepared. Not only is the resource recycled, but also the process steps are simplified, and the cost of the whole process is further reduced. In addition, the nitrogen-sulfur-containing regenerated gas is converted into a gas with no pollution as much as possible in the whole process, and there is no secondary pollution of gas in the production of the nitrosulfurammonia product.

[0043] Therefore, the low-temperature flue gas adsorption regeneration-based flue gas purification resource recycling system has the advantages of simplifying the process steps and low production cost.

[0044] As shown in FIG. 1, the nitrogen-sulfur-containing regenerated gas inlet 22 and the ozone inlet 21 are arranged at the bottom of the oxidation tower 2. The nitrogen-sulfur-containing regenerated gas and the ozone are fed from the bottom of the oxidation tower 2, and the water is sprayed from the top of the oxidation tower 2.

[0045] Further, the material of the oxidation tower 2 is glass steel, stainless steel or titanium steel.

[0046] Optionally, the water spraying device 26 can be communicated with the process water, so as to continuously and stably provide the spraying water.

[0047] As shown in FIG. 1, the oxidation tower 2 further comprises an acid liquid concentration pipeline 25, the oxidation tower 2 further has an acid liquid circulating inlet arranged at the upper portion thereof, the acid liquid outlet 23 is arranged at the bottom of the oxidation tower 2, one end of the acid liquid concentration pipeline 25 is communicated with the acid liquid outlet 23, the other end of the acid liquid concentration pipeline 25 is communicated with the acid liquid circulating inlet, and the acid liquid concentration pipeline 25 is switchably communicated with the reactor 3.

[0048] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure, by arranging the acid liquid concentration pipeline 25, the obtained acid liquid can be concentrated, and the obtained acid liquid can be circulated multiple times according to the yield of the nitrogen-sulfur-containing regenerated gas, so as to obtain high-concentration acid liquid, thereby facilitating the reduction of the cost of drying in the purification system 4. Thus, the production cost is further reduced.

[0049] As shown in FIGS. 1 and 2, the flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration further comprises an ozone destroyer 5, the ozone destroyer 5 is arranged between the excess gas outlet 24 of the oxidation tower 2 and the reactor 3, and is used for removing the ozone in the excess gas discharged from the oxidation tower 2.

[0050] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure, by arranging the ozone destroyer 5 between the excess gas outlet 24 of the oxidation tower 2 and the reactor 3. Further, the emission of the excess gas can be reduced (according to the reducibility of the gas in the nitrogen-sulfur-containing regenerated gas, the excess ozone and SO2 are in the excess gas), the excess ozone can be further reduced or removed by passing in SO2, and the problem of corrosion caused by the ozone entering the downstream reactor 3 and the purification system 4 can be prevented. Thus, the ozone destroyer 5 arranged can improve the service life of the downstream equipment. In addition, space can be provided for the reaction of SO2 and ozone in the excess gas, thereby facilitating the improvement of the purity of ammonium nitrate sulfate fertilizer.

[0051] Optionally, the excess gas outlet 24 is arranged at the top of the oxidation tower 2. Thus, the excess gas therein can be easily discharged.

[0052] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration further comprises a gas distributor, the gas distributor is arranged in the oxidation tower 2, and is used for uniformly dispersing the regenerated gas in the oxidation tower 2. Thus, the classification of the excess gas and ozone passing into the oxidation tower 2 is uniform, and the contact effectiveness between the ozone and the excess gas is improved. Thus, the nitrogen-sulfur-containing regenerated gas treatment efficiency is high.

[0053] As shown in FIG. 1 and FIG. 2, the flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure further comprises an ammonium nitrate concentration pipeline 34, the reactor 3 further has an ammonium nitrate liquid outlet 32 and an ammonium nitrate liquid circulation port 33, the ammonium nitrate concentration pipeline 34 is connected to the ammonium nitrate liquid outlet 32 and the ammonium nitrate liquid circulation port 33, and the ammonium nitrate liquid outlet 32 is switchably connected to the purification system 4 and the ammonium nitrate liquid circulation port 33.

[0054] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure can concentrate the obtained nitrosulfur ammonia solution through the set ammonium nitrate concentration pipeline 34, can cycle the obtained nitrosulfur ammonia solution multiple times according to the concentration of the nitrosulfur ammonia solution, so as to obtain nitrosulfur ammonia solution with a suitable concentration, and thus is conducive to reducing the cost of drying in the purification system 4. Therefore, the production cost is further reduced.

[0055] As shown in FIG. 1 and FIG. 2, the purification system 4 comprises a flash separator 41, a neutralization washing tower 42, a stirring mixing device 43, a flash tank 44 and an evaporator 45, the gas phase outlet of the flash separator 41 is connected to the gas phase inlet of the neutralization washing tower 42 through a pipeline, the liquid phase outlet of the flash separator 41 is connected to the liquid phase inlet of the stirring mixing device 43 through a pipeline, the gas phase outlet of the neutralization washing tower 42 is connected to the gas phase inlet of the stirring mixing device 43 through a pipeline, the discharge port of the stirring mixing device 43 is connected to the feed port of the flash tank 44 through a pipeline, the discharge port of the flash tank 44 is connected to the feed port of the evaporator 45 through a pipeline, the steam outlet of the neutralization washing tower 42 is connected to the steam inlet of the evaporator 45 through a pipeline, and the discharge port of the evaporator 45 is connected to a filter pressing device (not shown).

[0056] The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure divides the purification system 4 into the flash separator 41, the neutralization washing tower 42, the stirring mixing device 43, the flash tank 44 and the evaporator 45,

[0057] Specifically, one end of a reflux pipe is connected to the pipeline between the gas phase outlet of the neutralization washing tower 42 and the gas phase inlet of the stirring mixing device 43 through a three-way pipe fitting, and the other end of the reflux pipe is connected to the reflux inlet of the neutralization washing tower 42. The dilute ammonium nitrate solution discharged from the neutralization washing tower 42 is used as an absorption liquid and is transported back to the neutralization washing tower 42 to repeatedly wash the ammonia-containing steam; and the liquid level at the bottom of the tower can also be maintained. The steam outlet of the neutralization washing tower 42 is connected to the steam inlet of the evaporator 45 through a pipeline. After the ammonia in the ammonia-containing steam is removed in the neutralization washing tower 42, process steam is obtained and is introduced into the evaporator 45 to be used as a heat source for evaporating dry materials.

[0058] Further, a first pump body is connected between the liquid phase outlet of the oxidation tower 2 and the liquid phase inlet of the reactor 3, a second pump body is connected between the liquid phase outlet of the flash separator 41 and the liquid phase inlet of the stirring and mixing device 43, and a third pump body is connected between the discharge port of the stirring and mixing device 43 and the feed port of the flash tank 44.

[0059] The nitrogen and sulfur-containing regenerated gas includes the following components by volume: SO2 28-30%, NO x 4.8-5.2%, N2 42-44%, CO2 4-6%, H2O 19-21%. The flue gas purification resource recycling system based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure is advantageous to improve the sufficiency of resource utilization by controlling the proportion of the components of the nitrogen and sulfur-containing regenerated gas. The nitrosulfurammonia product produced by the gas proportion can be directly used as nitrosulfurammonia fertilizer without treatment, and further treatment is no longer needed. Thus, the application efficiency of the nitrosulfurammonia product is improved.

[0060] The ozone-oxidized regenerated gas includes the following components by volume: SO2 30-32%, N2 43-45%, CO2 3-4%, H2O 19-21%.

[0061] The flue gas purification resource recycling method based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure is carried out by using the flue gas purification resource recycling system. The flue gas purification resource recycling method includes the following steps:

[0062] The flue gas is cooled by the cooling device 11 to obtain low-temperature flue gas at subzero temperature;

[0063] The low-temperature flue gas is introduced into the adsorption device 12 to obtain clean flue gas and saturated adsorbent;

[0064] The saturated adsorbent is regenerated to obtain regenerated adsorbent and nitrogen and sulfur-containing regenerated gas;

[0065] The nitrogen and sulfur-containing regenerated gas is ozone-oxidized in the oxidation tower 2 and water is sprayed to obtain acid liquor;

[0066] The ammonia water, the acid liquor in the oxidation tower 2, and the residual gas and the ammonia water are introduced into the reactor 3 to react to obtain a nitrosulfurammonia solution;

[0067] The nitrosulfurammonia solution is sequentially subjected to solid-liquid separation and drying to obtain a nitrosulfurammonia product.

[0068] Thus, the flue gas purification resource recycling method based on low-temperature flue gas adsorption regeneration of the embodiment of the present disclosure has the advantages of simplifying the process steps and reducing the production cost.

[0069] Specifically, the flue gas purification resource recycling method includes the following steps:

[0070] S1, cooling the flue gas by the cooling device 11 to obtain low-temperature flue gas at subzero temperature; introducing the low-temperature flue gas into the adsorption device 12 to obtain clean flue gas and saturated adsorbent; regenerating the adsorption-saturated adsorbent to obtain regenerated adsorbent and nitrogen-containing and sulfur-containing regenerated gas;

[0071] S2, introducing the regenerated gas generated after the flue gas from the plant is desulfurized and denitrified into the oxidation tower 2 for oxidation, while spraying process water (circulating water in the plant, for example, water obtained through solid-liquid separation) from top to bottom, and the gas-liquid phases are countercurrently mass-contacted in the oxidation tower 2, and the process water reacts with the oxidized acid gas to generate acid liquid;

[0072] S3, introducing the acid liquid in S2 into the reactor 3, and introducing the gas discharged from the top of the oxidation tower 2 into the reactor 3 after being treated by the ozone destroyer 5, and introducing ammonia water into the reactor 3 to react with the acid liquid in S2 and the gas treated by the ozone destroyer 5 to generate a gas-liquid mixture, and introducing the gas-liquid mixture into the flash separator 41;

[0073] S4, introducing the ammonia-containing steam after the flash into the neutralization washing tower 42 for washing to obtain dilute ammonium nitrate solution, and introducing the dilute ammonium nitrate solution into the stirring and mixing device 43; at the same time, introducing the liquid after the flash into the stirring and mixing device 43 for reaction to generate a supersaturated solution of ammonium nitrate sulfate and ammonium nitrate sulfate crystalline salt.

[0074] The liquid in the stirring and mixing device 43 is a mixed solution of ammonium nitrate and ammonium sulfate. The reaction equations involved are: 2NH3·H2O + H2SO4 = (NH4)2SO4 + 2H2O, NH3·H2O + HNO3 = NH4NO3 + H2O.

[0075] S5, introducing the supersaturated solution of ammonium nitrate sulfate and the ammonium nitrate sulfate crystalline salt into the flash tank 44, converting the supersaturated solution of ammonium nitrate sulfate into the ammonium nitrate sulfate crystalline salt, discharging water vapor, then introducing the ammonium nitrate sulfate crystalline salt after the discharge of water vapor into the evaporator 45 to remove water to obtain solid ammonium nitrate sulfate crystalline salt, and finally conveying the solid ammonium nitrate sulfate crystalline salt to the filter press for pressure filtration to form ammonium nitrate sulfate filter cake, drying the ammonium nitrate sulfate filter cake to obtain ammonium nitrate sulfate product, i.e., ammonium nitrate sulfate fertilizer.

[0076] It should be noted that, as shown in FIG. 2, the low-temperature flue gas adsorption regeneration system 1 (COAP system) in the embodiment of the present disclosure includes the cooling device 11, the adsorption device 12, and the regeneration device 13. The flue gas from the plant is formed into cooled flue gas after being sprayed into the spray cooling tower, introduced into the adsorption regeneration system, discharged as regenerated gas, and then introduced into the oxidation tower 2.

[0077] Further, the ozone is prepared by an ozone generator.

[0078] Further, in step S2, the temperature in the reactor 3 is 160-180℃, the pressure is 2.5-3.5MPa, and the concentration of the ammonia water added is 22-27%. Alternatively, the concentration of the ammonia water is 25%.

[0079] Further, in step S3, the operating temperature of the flash separator 41 is 110-130℃.

[0080] Further, in step S3, the reaction temperature in the stirring mixing device 43 is 70-90℃, the reaction time is 30-100min, and the pressure is 1.5MPa. The stirring mixing device 43 is provided with a stirring paddle, and the stirring speed is 40-90rpm.

[0081] Further, in the reactor 3, the ratio of pure ammonia in the ammonia water to pure nitric acid and pure sulfuric acid is 3-4:2:1.

[0082] Further, in the reactor 3, the residence time of the gas in the reactor 3, i.e. the reaction time, is 5-20min.

[0083] Further, in step S3, the washing liquid of the neutralization washing tower 42 is nitric acid. The gas coming out of the flash separator 41 is ammonia-containing steam, which is introduced into the neutralization washing tower 42 to wash the ammonia in the steam. The ammonia water reacts with the nitric acid to generate a low-concentration ammonium nitrate solution, which falls to the bottom of the neutralization washing tower 42. Since there is more nitric acid, the overall solution is acidic. Therefore, it helps to improve the purity of the nitrosulfur ammonia product.

[0084] The acid liquid can be introduced into the reactor 3 when the pH of the acid liquid is 4-5.

[0085] Further, in step S1, the acid liquid generated is dilute nitric acid, nitrous acid, dilute sulfurous acid, and dilute sulfuric acid.

[0086] Further, the gas pressure in the flash tank 44 is 0.1-0.3MPa, and the temperature is 120-140℃. Alternatively, the gas pressure in the flash tank 44 is 0.2MPa, and the temperature is 130℃.

[0087] Alternatively, the adsorbent device 12 uses an adsorbent to adsorb the flue gas at low temperature. The adsorbent can be a granular or powdery adsorbent, or an adsorbent body made of a powdery or granular adsorbent, such as a spherical body or a cylindrical body formed by the powdery or granular adsorbent through a binder, etc. Of course, a protective shell can be further formed on the outside of the adsorbent body, such as a gas-permeable membrane covering the outside of the adsorbent body, to improve the strength of the adsorbent body. The adsorbent can be in the form of an adsorption unit, which includes a gas-permeable shell and an adsorbent filled in the gas-permeable shell. The diameter of the adsorbent particles is 1mm-10mm, and the diameter of the adsorbent is 10mm-100mm.

[0088] It should be noted that the basic principle of the low-temperature flue gas adsorbent is to remove the pollutant components from the low-temperature flue gas by adsorption. In a low-temperature environment, usually below room temperature, optionally below zero degrees Celsius, more optionally, the low temperature is-20℃ to-5℃, the nitrogen oxides in the flue gas undergo low-temperature oxidation adsorption on the surface of the adsorbent such as activated carbon, and the difficult-to-adsorb nitric oxide gas is oxidized into the easy-to-adsorb nitrogen dioxide gas, which can achieve a growth of hundreds of times in adsorption capacity. In addition, the adsorption capacity of sulfur dioxide, carbon dioxide and heavy metals is also multiplied in a low-temperature environment.

[0089] The inventor found through research that the lower the flue gas temperature, the more beneficial to adsorption purification, but too low flue gas temperature leads to complex equipment structure and increased energy consumption, for example, the cooling device, the adsorption device and the pipeline require insulation layers, and the sealing requirement is high, thereby increasing the cost, in addition, too low temperature conditions lead to easy condensate water in the adsorption device, causing the adsorbent to stick and block, affecting adsorption. Therefore, the low-temperature flue gas temperature is-20℃ to-5℃. In the description of the present disclosure, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure.

[0090] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0091] In the present disclosure, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected or in communication with each other; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0092] In the present disclosure, unless specifically stated and limited otherwise, a first feature "on" or "under" a second feature can be directly contacting the first and second features, or indirectly contacting the first and second features through an intermediate medium. Also, the first feature "over", "above" and "on top of" the second feature can be directly above or obliquely above the second feature, or simply means that the first feature is higher in horizontal level than the second feature. The first feature "under", "below" and "underneath" the second feature can be directly below or obliquely below the second feature, or simply means that the first feature is lower in horizontal level than the second feature.

[0093] In the present disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material or characteristic is included in at least one embodiment or example of the present disclosure. In the specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the described specific features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples. In addition, different embodiments or examples described in the specification and features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0094] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present disclosure, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present disclosure.

Claims

1. A flue gas purification and resource reuse system based on low-temperature flue gas adsorption and regeneration, comprising: A low-temperature flue gas adsorption and regeneration system includes a cooling device, an adsorption device, and a regeneration device. The cooling device is used to cool the flue gas to a low-temperature flue gas temperature below zero. The adsorption device is used to adsorb and purify the low-temperature flue gas into clean flue gas using an adsorbent. The regeneration device is used to regenerate the adsorbent that has been saturated with adsorption and generate nitrogen- and sulfur-containing regeneration gas. An oxidation tower is provided, which is equipped with a water spraying device. The oxidation tower has a nitrogen-sulfur regeneration gas inlet, an ozone inlet for supplying ozone into the oxidation tower, an acid outlet for discharging acid from the oxidation tower, and a residual gas outlet for discharging residual gas from the oxidation tower. The nitrogen-sulfur regeneration gas inlet of the oxidation tower is connected to the nitrogen-sulfur regeneration gas outlet of the regeneration device. The nitrogen-sulfur regeneration gas discharged from the regeneration device is oxidized by ozone in the oxidation tower to become ozone-oxidized regeneration gas. The ozone-oxidized regeneration gas is sprayed by the water spraying device to obtain acid. A reactor having an ammonia inlet for supplying ammonia water into the reactor, the reactor being connected to the acid outlet and residual gas outlet of the oxidation tower, wherein acid water and residual gas discharged from the oxidation tower enter the reactor and react with the ammonia water supplied to the reactor through the ammonia inlet in the reactor to obtain a nitrate-sulfur-ammonia solution. A purification system, connected to the reactor, is used to purify the ammonium nitrate solution discharged from the reactor to obtain the ammonium nitrate product.

2. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption and regeneration according to claim 1, wherein the oxidation tower further includes an acid concentration pipeline, the oxidation tower also has an acid circulation inlet located at its upper part, the acid outlet is located at the bottom of the oxidation tower, one end of the acid concentration pipeline is connected to the acid outlet, the other end of the acid concentration pipeline is connected to the acid circulation inlet, and the acid concentration pipeline is switchably connected to the reactor.

3. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption and regeneration according to claim 1 or 2 further includes an ozone destroyer, which is disposed between the residual gas outlet of the oxidation tower and the reactor, for removing ozone from the residual gas discharged from the oxidation tower.

4. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption and regeneration according to any one of claims 1-3, wherein the residual gas outlet is located at the top of the oxidation tower.

5. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption regeneration according to any one of claims 1-4 further includes a gas distributor, which is disposed in the oxidation tower for uniformly dispersing the regeneration gas in the oxidation tower.

6. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption regeneration according to any one of claims 1-5 further includes an ammonium nitrate concentration pipeline, the reactor further having an ammonium nitrate liquid outlet and an ammonium nitrate liquid circulation port, the ammonium nitrate concentration pipeline connecting the ammonium nitrate liquid outlet and the ammonium nitrate liquid circulation port, and the ammonium nitrate liquid outlet being switchably connected to the purification system and the ammonium nitrate liquid circulation port.

7. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption regeneration according to any one of claims 1-6, wherein the purification system comprises a flash separator, a neutralization and washing tower, a stirring and mixing device, a flash tank, and an evaporator; the gas phase outlet of the flash separator is connected to the gas phase inlet of the neutralization and washing tower via a pipeline; the liquid phase outlet of the flash separator is connected to the liquid phase inlet of the stirring and mixing device via a pipeline; the gas phase outlet of the neutralization and washing tower is connected to the gas phase inlet of the stirring and mixing device via a pipeline; the discharge port of the stirring and mixing device is connected to the feed port of the flash tank via a pipeline; the discharge port of the flash tank is connected to the feed port of the evaporator via a pipeline; the steam outlet of the neutralization and washing tower is connected to the steam inlet of the evaporator via a pipeline; and the discharge port of the evaporator is connected to a filter press.

8. The flue gas purification and resource reuse system based on low-temperature flue gas adsorption regeneration according to any one of claims 1-7, wherein the nitrogen- and sulfur-containing regeneration gas comprises, by volume, the following components: SO2 28-30%, NO x 4.8-5.2%, N242-44%, CO24-6%, H2O 19-21%; And / or, the ozone oxidation regeneration gas comprises, by volume, the following components: SO2: 30-32%, N2: 43-45%, CO2: 3-4%, H2O: 19-21%.

9. A method for resource reuse of flue gas purification based on low-temperature flue gas adsorption and regeneration, comprising the following steps: The flue gas is cooled by a cooling device to obtain low-temperature flue gas with a temperature below zero. Low-temperature flue gas is passed into an adsorption device to obtain clean flue gas and saturated adsorbent. The adsorbent that has become saturated with adsorption is regenerated to obtain a regenerated adsorbent and a nitrogen- and sulfur-containing regenerated gas. The nitrogen- and sulfur-containing regenerated gas is oxidized by ozone in an oxidation tower and then sprayed with water to obtain an acid solution. Ammonia water, acid solution and residual gas in the oxidation tower are introduced into the reactor to react with ammonia water to obtain a nitrate-sulfur-ammonia solution. The ammonium nitrate solution is subjected to solid-liquid separation and drying in sequence to obtain the ammonium nitrate product.

10. The flue gas purification and resource reuse method based on low-temperature flue gas adsorption regeneration according to claim 9, wherein the nitrogen- and sulfur-containing regeneration gas comprises, by volume, the following components: SO2 28-30%, NO... x 4.8-5.2%, N242-44%, CO24-6%, H2O 19-21%; And / or, the ozone oxidation regeneration gas comprises, by volume, the following components: SO2: 30-32%, N2: 43-45%, CO2: 3-4%, H2O: 19-21%.

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