Energy-saving ammonia desulfurization device

Abstract

The utility model relates to a kind of energy-saving ammonia desulfurization device, belong to chemical technology field, comprising: desulfurization tower;Oxidation mixed gas preheater, absorption liquid circulating pump, ammonium sulfate circulating tank, waste water circulating pump and lean liquid circulating pump connected with desulfurization tower respectively;The lean liquid circulating pump is connected with ammonium sulfate circulating tank;Waste water collecting tank connected with ammonium sulfate circulating tank and waste water circulating pump respectively;Solid delivery pump is connected with ammonium sulfate circulating tank.The utility model improves ammonium sulfate crystal quality and system operating efficiency by comprehensive utilization of flue gas energy and precise control of ammonium sulfate grain size, realizes the purpose of byproduct ammonium sulfate upgrading and efficiency increasing, ammonia desulfurization system efficient operation.

Description

Technical Field

[0001] This utility model belongs to the field of chemical technology, specifically relating to an energy-saving ammonia desulfurization device. Background Technology

[0002] Ammonium sulfate is a fast-acting fertilizer and a bio-fertilizer, and it is also a common method for utilizing SO2 through wet ammonia desulfurization in the steel and coal-fired power industries. The wet ammonia process has evolved from the earliest Walther ammonia process to the AMASOX, GE, NKK, and EADS processes, mainly consisting of SO2 absorption, ammonium sulfite oxidation, and treatment of the byproduct ammonium sulfate. Its development has primarily focused on simplifying the process and reducing energy and material consumption, manifested in changes such as the shift from multi-tower to single-tower tower configurations, the shift from external to internal crystallization locations, the shift from externally heated crystallization to waste heat crystallization from flue gas, and the shift from circulating water scrubbing to ammonium sulfate lean solution scrubbing. In recent years, the application of ammonia desulfurization technology has gradually transitioned from the coal chemical industry to the petrochemical industry.

[0003] Based on the above development history, Chinese patent CN103223292A discloses a method and device for treating acidic tail gas using ammonia. This is a highly efficient ammonia desulfurization technology commonly used in domestic coal chemical plants, integrating flue gas absorption, oxidation, concentration and crystallization, dust removal, and demisting. Based on this, Chinese patent CN103521060A discloses a method for treating sulfur recovery tail gas using ammonia desulfurization of boiler flue gas, mainly applied to scenarios involving mixed flue gas (sulfur recovery tail gas after combustion and boiler flue gas) using ammonia desulfurization. Chinese patent CN104941423A discloses a method and device for ammonia desulfurization, denitrification, and dust removal of catalytic cracking regenerated flue gas. This is an integrated technology for desulfurization, denitrification, and dust removal of catalytic cracking regenerated flue gas based on ammonia desulfurization and denitrification, extending its application to catalytic cracking processes. Chinese patent CN105126573A discloses an integrated ammonia-based desulfurization method for multiple acidic gases in oil refining units. This method simplifies the desulfurization process for FCC flue gas, incineration flue gas, and regenerated flue gas in oil refining units, reducing desulfurization costs and wastewater emissions. Currently, existing ammonia-based desulfurization processes still suffer from problems such as small (NH4)2SO4 crystals in ammonium sulfate and centrifuge blockage preventing separation during actual operation, thus reducing system operating efficiency. This is mainly attributed to the explosive nucleation of ammonium sulfate crystals when low-grade energy flue gas instantaneously contacts the lean ammonium sulfate solution. Furthermore, the ammonium sulfate spraying temperature in the evaporation and crystallization section is affected by season and solid content, the absorption and oxidation process is relatively long, and its absorption efficiency is affected by the matching of ammonium sulfate circulation volume with the energy level of the flue gas.

[0004] It is evident that developing an energy-saving ammonia desulfurization device that utilizes flue gas energy in stages and phases, rationally matches the ammonium sulfate circulation volume with flue gas energy, allows for appropriate growth of ammonium sulfate crystals, couples absorption and oxidation, and controls the temperature and solid content of the ammonium sulfate circulating spray. This not only facilitates the comprehensive utilization of flue gas energy and precise control of ammonium sulfate crystal size, but also improves absorption and oxidation efficiency, simplifies the process flow, and ultimately enhances the quality and efficiency of the byproduct ammonium sulfate and ensures the efficient operation of the ammonia desulfurization system. Ultimately, this promotes the comprehensive treatment of acidic gases and the resource utilization of sulfur in the fields of coal chemical and petrochemical industries, and has certain economic, environmental, and social benefits. Utility Model Content

[0005] To address the problems of small ammonium sulfate crystals, centrifuge blockage leading to separation failure, and low system operating efficiency in existing ammonia desulfurization processes, this invention provides an energy-saving ammonia desulfurization device.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] This utility model provides an energy-saving ammonia desulfurization device, comprising:

[0008] The desulfurization tower has, from top to bottom, a washing and demisting section, an absorption coupled oxidation section, a preliminary oxidation section, an evaporation and crystallization section, and an oxidation section; the evaporation and crystallization section is divided into an upper layer and a lower layer.

[0009] An oxidation mixed gas preheater connected to the oxidation section of the desulfurization tower;

[0010] Absorbent liquid circulation pumps are respectively connected to the oxidation section, the lower layer of the evaporation and crystallization section, and the washing and demisting section of the desulfurization tower;

[0011] An ammonium sulfate circulation tank connected to the lower layer of the evaporation and crystallization section of the desulfurization tower;

[0012] Wastewater circulation pump connected to the upper layer of the evaporation and crystallization section of the desulfurization tower;

[0013] Lean liquor circulation pumps are connected to the preliminary oxidation section of the desulfurization tower and the ammonium sulfate circulation tank, respectively;

[0014] Wastewater collection tanks are connected to the ammonium sulfate circulation tank and the wastewater circulation pump, respectively.

[0015] Furthermore, the ammonium sulfate circulation tank consists of an ammonium sulfate receiving tank, an ammonium sulfate pre-separation tank, and an ammonium sulfate conveying tank; the ammonium sulfate receiving tank is connected to the ammonium sulfate pre-separation tank and the ammonium sulfate conveying tank respectively; the ammonium sulfate receiving tank is connected to the lower layer of the evaporation and crystallization section of the desulfurization tower; the wastewater collection tank and the lean liquid circulation pump are respectively connected to the ammonium sulfate conveying tank.

[0016] Furthermore, the ammonium sulfate receiving tank is equipped with sparse tube arrays.

[0017] Furthermore, the ammonium sulfate receiving tank is connected to the bottom of the ammonium sulfate pre-separation tank to achieve pre-separation of ammonium sulfate solids.

[0018] Furthermore, the ammonium sulfate receiving tank is connected to the top of the ammonium sulfate conveying tank to convey the ammonium sulfate lean solution in an overflow manner.

[0019] Furthermore, the energy-saving ammonia desulfurization device of this utility model also includes a solid transfer pump connected to the ammonium sulfate pre-separation tank.

[0020] Furthermore, the washing and demisting section of the desulfurization tower is connected to an external liquid ammonia source.

[0021] Furthermore, the preliminary oxidation section of the desulfurization tower is connected to an external air source.

[0022] Furthermore, sulfur dioxide-containing flue gas is introduced into both the upper and lower layers of the evaporation and crystallization section of the desulfurization tower.

[0023] Furthermore, the preliminary oxidation section of the desulfurization tower is connected to the oxidation section.

[0024] The beneficial effects of this utility model are:

[0025] This invention provides an energy-saving ammonia-based desulfurization device that solves the problems of small ammonium sulfate crystals, centrifuge blockage leading to separation failure, and low system operating efficiency in existing ammonia-based desulfurization processes. This invention utilizes flue gas energy in a segmented and graded manner, and rationally matches the flue gas energy through ammonium sulfate circulation. Furthermore, it achieves the resource utilization of high-quality ammonium sulfate byproducts from SO2-containing flue gas through appropriate ammonium sulfate crystal growth and absorption-oxidation coupling processes. The ammonium sulfate circulation spray temperature and solid content are both adjustable.

[0026] This invention improves absorption and oxidation efficiency, ammonium sulfate crystal quality, and system operating efficiency by comprehensively utilizing flue gas energy and precisely controlling ammonium sulfate crystal size. It simplifies the process flow, achieves the goal of improving the quality and efficiency of by-product ammonium sulfate and ensuring the efficient operation of the ammonia desulfurization system, and promotes the comprehensive treatment of acidic gas and the resource utilization of sulfur in the fields of coal chemical and petrochemical industries. It has certain economic, environmental and social benefits. Attached Figure Description

[0027] Figure 1 A flowchart of an energy-saving ammonia desulfurization device provided by this utility model.

[0028] In the diagram, there are: 1. Oxidation mixed gas preheater; 2. Desulfurization tower; 3. Absorbent liquid circulation pump; 4. Solid transfer pump; 5. Ammonium sulfate circulation tank; 6. Wastewater circulation pump; 7. Lean liquid circulation pump; 8. Ammonium sulfate pre-separation tank; 9. Ammonium sulfate transfer tank; 10. Wastewater collection tank; and 11. Ammonium sulfate receiving tank. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings.

[0030] Firstly, this utility model provides an energy-saving ammonia desulfurization process that improves the quality and efficiency of ammonium sulfate.

[0031] This invention, combining the characteristics of the development history of wet ammonia desulfurization, creatively establishes an energy-saving ammonia desulfurization process that improves the quality and efficiency of ammonium sulfate. This invention comprehensively utilizes flue gas energy, precisely controls the ammonium sulfate crystal size, and adjusts the ammonium sulfate circulating spray temperature and solid content to achieve appropriate ammonium sulfate crystal growth. Simultaneously, this invention also achieves efficient conversion of sulfur dioxide through absorption coupled with initial oxidation. In this process, flue gas energy is comprehensively utilized in both the evaporation and crystallization and oxidation processes. During the evaporation and crystallization process, the flue gas comes into contact with centrifuge wastewater, high ammonia nitrogen wastewater, and ammonium sulfate lean solution in stages. During the oxidation process, steam assists in heating the mixture of flue gas and air. The wastewater pre-washing volume is precisely adjusted using wastewater circulation pump 6, while the ammonium sulfate lean solution circulation volume is precisely adjusted using lean solution circulation pump 7 to reasonably match the flue gas energy. The ammonium sulfate circulation tank 5 is designed with a circulating cooling system (ammonium sulfate receiving tank 11 and ammonium sulfate conveying tank 9) and an ammonium sulfate pre-separation tank 8. The bottom overflow layer of the absorption-coupled oxidation section of the desulfurization tower 2 is blew in dust removal and cooling sulfur-containing flue gas and supplemented with air to initially oxidize ammonium sulfite. Then, it comes into countercurrent contact with the absorbent liquid to achieve deep absorption of sulfur dioxide and deep oxidation of ammonium sulfite through the absorption-coupled oxidation process.

[0032] See Figure 1 The present invention provides an energy-saving ammonia desulfurization process for improving the quality and efficiency of ammonium sulfate, the specific implementation process of which is as follows:

[0033] Step S1: Segmented and graded utilization of flue gas energy;

[0034] Sulfur dioxide-containing flue gas from coal chemical and petrochemical plants is introduced into the oxidation section, the upper layer of the evaporation and crystallization section, and the lower layer of the evaporation and crystallization section of desulfurization tower 2 in stages; air is introduced into the preliminary oxidation section and oxidation section of desulfurization tower 2 in stages.

[0035] A portion of the sulfur dioxide-containing flue gas enters the upper and lower layers of the evaporation and crystallization section of desulfurization tower 2 in stages; the sulfur dioxide-containing flue gas in the upper layer of the evaporation and crystallization section of desulfurization tower 2 comes into countercurrent contact with the sprayed ammonium sulfate lean solution, and the sulfur dioxide-containing flue gas in the lower layer of the evaporation and crystallization section of desulfurization tower 2 comes into countercurrent contact with centrifuge wastewater and high ammonia nitrogen wastewater.

[0036] Another part of the flue gas containing sulfur dioxide is premixed with air and then heated by the oxidizing mixed gas preheater 1 before entering the oxidation section of the desulfurization tower 2. In the oxidation section of the desulfurization tower 2, dust removal and deep oxidation of ammonium sulfite are carried out. Finally, the gas phase of the desulfurization tower 2 passes through the oxidation section of the desulfurization tower 2 to the evaporation and crystallization section of the desulfurization tower 2.

[0037] Among them, the sulfur-containing flue gas after dust removal and cooling in the evaporation and crystallization section of desulfurization tower 2 is then subjected to absorption of sulfur dioxide by absorption liquid (liquid ammonia and dilute ammonium sulfate solution), and after washing and demisting, it is discharged in compliance with standards (to the atmosphere).

[0038] Step S2: Ammonium sulfate crystals grow at an appropriate rate;

[0039] S2.1: Centrifuge wastewater and high ammonia nitrogen wastewater are collected into wastewater collection tank 10. The centrifuge wastewater and high ammonia nitrogen wastewater sprayed by the wastewater circulation pump 6 are in countercurrent contact with the sulfur dioxide-containing flue gas in the lower layer of the evaporation and crystallization section of the desulfurization tower 2 to achieve online dust removal and cooling of flue gas.

[0040] S2.2: The ammonium sulfate lean solution, with its spray volume adjusted by the frequency conversion of the lean solution circulation pump 7, countercurrently contacts the sulfur dioxide-containing flue gas in the upper layer of the evaporation and crystallization section of the desulfurization tower 2 to achieve deep dust removal and step-by-step cooling of the flue gas;

[0041] S2.3: The ammonium sulfate rich solution in the lower layer of the evaporation and crystallization section of desulfurization tower 2 flows into the ammonium sulfate circulation tank 5. The ammonium sulfate circulation tank 5 consists of an ammonium sulfate receiving tank 11, an ammonium sulfate pre-separation tank 8, and an ammonium sulfate conveying tank 9. The ammonium sulfate receiving tank 11 is equipped with sparse tubes for temperature control. In addition, the stirring rate and connection method of the ammonium sulfate receiving tank 11, the ammonium sulfate pre-separation tank 8, and the ammonium sulfate conveying tank 9 are different: the bottom of the ammonium sulfate receiving tank 11 is connected to the bottom of the ammonium sulfate pre-separation tank 8 to achieve the pre-separation of ammonium sulfate solids and control the ammonium sulfate solid content in the ammonium sulfate lean solution. The tops of the ammonium sulfate receiving tank 11 and the ammonium sulfate conveying tank 9 are connected to convey the ammonium sulfate lean solution by overflow. The liquid level of the ammonium sulfate conveying tank 9 can be adjusted in time by replenishing the centrifuge wastewater and high ammonia nitrogen wastewater in the wastewater collection tank 10 and the dilute ammonium sulfate solution in the oxidation section of desulfurization tower 2. Among them, the ammonium sulfate solids in the ammonium sulfate pre-separation tank 8 are conveyed to the centrifuge for separation by the solid transfer pump 4 (to the centrifuge).

[0042] S2.4: The flow rate of ammonium sulfate lean solution is adjusted by frequency conversion of the lean solution circulation pump 7 to control the temperature of the upper spray layer of the evaporation and crystallization section of the desulfurization tower 2, thereby achieving appropriate growth of ammonium sulfate crystals.

[0043] Step S3: Absorption coupled with oxidation to improve absorption efficiency and oxidation depth;

[0044] Air is introduced into the absorbent receiving layer of the preliminary oxidation section of desulfurization tower 2 to initially oxidize ammonium sulfite. The liquid phase flows into the oxidation section of desulfurization tower 2, while the gas phase mixes with the dust-removed and cooled sulfur-containing flue gas and then flows countercurrently into the absorbent liquid (liquid ammonia and dilute ammonium sulfate solution) in the absorption-coupled oxidation section of desulfurization tower 2. This achieves deep absorption of sulfur dioxide and deep oxidation of ammonium sulfite, i.e., absorption-coupled oxidation process. This process promotes the oxidation of the absorption product ammonium sulfite, improves the absorption efficiency of sulfur dioxide, and reduces the oxidation load of the oxidation section. Finally, the process passes through the scrubbing and demisting section of desulfurization tower 2 to achieve the goals of sulfur dioxide emission compliance, ammonia escape, and effective control of aerosols.

[0045] In this process, a fixed amount of dilute ammonium sulfate solution is transported to the middle layer of the evaporation and crystallization section and the upper layer of the absorption-coupled oxidation section via the absorbent circulation pump 3. Based on the liquid level in the ammonium sulfate transport tank 9, a fixed amount of dilute ammonium sulfate solution is replenished and transported to the middle layer of the evaporation and crystallization section to ensure the normal operation of the lean solution circulation pump 7. Liquid ammonia is added to the dilute ammonium sulfate solution and sprayed onto the upper layer of the absorption-coupled oxidation section, which can efficiently regulate the pH of the absorption process and reduce the probability of ammonia escape.

[0046] The main process parameters involved in the energy-saving ammonia desulfurization process for improving the quality and efficiency of ammonium sulfate provided by this utility model are as follows:

[0047] The sulfur dioxide concentration in the flue gas entering desulfurization tower 2 is ≤50000 mg / Nm³. 3 ;

[0048] Gas velocity in the empty tower of desulfurization tower 2: 3m / s-6.5m / s;

[0049] Liquid-to-gas ratio in the evaporation and crystallization section of desulfurization tower 2: ≤15L / m 3 ;

[0050] Flue gas temperature in the evaporation and crystallization section of desulfurization tower 2: ≤190℃;

[0051] Temperature of the upper spray layer in the evaporation and crystallization section of desulfurization tower 2: ≤55℃;

[0052] Temperature of the lower spray layer in the evaporation and crystallization section of desulfurization tower 2: ≤90℃;

[0053] Temperature of sulfur-containing flue gas entering the absorption coupled oxidation section of desulfurization tower 2: ≤55℃;

[0054] Temperature of the spray layer in the absorption coupled oxidation section of desulfurization tower 2: ≤50℃;

[0055] Liquid-to-gas ratio in the absorption coupled oxidation section of desulfurization tower 2: 1 L / m³ 3 -25L / m 3 ;

[0056] pH of the absorption solution: 5-8;

[0057] Solid transfer pump 4 transports products with an ammonium sulfate solid content ≥15%;

[0058] The lean liquid circulation pump 7 delivers products with an ammonium sulfate solid content ≤10%;

[0059] Ammonium sulfate grains ≥100 mesh.

[0060] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0061] This embodiment provides an energy-saving ammonia desulfurization process for improving the quality and efficiency of ammonium sulfate, the specific implementation process of which is as follows:

[0062] Step S1: Segmented and graded utilization of flue gas energy;

[0063] The empty gas velocity of desulfurization tower 2 is 4.5 m / s, and the total sulfur dioxide content of the boiler flue gas is 51375 Nm³. 3 / h, the temperature of the flue gas containing sulfur dioxide is 170℃, and the sulfur dioxide concentration of the flue gas entering desulfurization tower 2 is 14400mg / Nm³. 3 The pressure is 4700Pa, and the flue gas containing sulfur dioxide is introduced into the oxidation section of desulfurization tower 2, the lower layer of the evaporation and crystallization section of desulfurization tower 2, and the upper layer of the evaporation and crystallization section of desulfurization tower 2 respectively in a volume ratio of 1:3:1.

[0064] Flue gas containing sulfur dioxide is divided into stages and enters the oxidation section, the upper layer of the evaporation and crystallization section, and the lower layer of the evaporation and crystallization section of desulfurization tower 2; air is divided into stages and enters the preliminary oxidation section and oxidation section of desulfurization tower 2.

[0065] A portion of the sulfur dioxide-containing flue gas enters the upper and lower layers of the evaporation and crystallization section of desulfurization tower 2 in stages. In the upper layer of the evaporation and crystallization section, the sulfur dioxide-containing flue gas comes into countercurrent contact with the sprayed ammonium sulfate lean solution, while in the lower layer, it comes into countercurrent contact with centrifuge wastewater and high-ammonia nitrogen wastewater. After passing through the evaporation and crystallization section of desulfurization tower 2, the dust-removed and cooled sulfur-containing flue gas is further treated by the absorption liquid (liquid ammonia and dilute ammonium sulfate solution) to absorb sulfur dioxide, and after washing and demisting, it meets emission standards (to the atmosphere).

[0066] Another part of the flue gas containing sulfur dioxide is premixed with air and then heated to 105°C by the oxidizing mixed gas preheater 1 before entering the oxidation section of the desulfurization tower 2 for dust removal and deep oxidation of ammonium sulfite. Finally, the gas phase of the gas enters the evaporation and crystallization section of the desulfurization tower 2.

[0067] Step S2: Ammonium sulfate crystals grow at an appropriate rate;

[0068] S2.1: Centrifuge wastewater and high-ammonia-nitrogen wastewater are collected in wastewater collection tank 10. The centrifuge wastewater and high-ammonia-nitrogen wastewater, with their spray volume adjusted by the wastewater circulation pump 6, flow counter-currently to contact the sulfur dioxide-containing flue gas in the lower layer of the evaporation and crystallization section of desulfurization tower 2, achieving online dust removal and cooling of the flue gas; wherein, the liquid-to-gas ratio in the lower layer of the evaporation and crystallization section of desulfurization tower 2 is 3L / m³. 3 The temperature of the lower spray layer in the evaporation and crystallization section of desulfurization tower 2 is ≤90℃;

[0069] S2.2: The ammonium sulfate lean solution, with its spray volume adjusted by the frequency converter of the lean solution circulation pump 7, countercurrently contacts the sulfur dioxide-containing flue gas in the upper layer of the evaporation and crystallization section of the desulfurization tower 2 to achieve deep dust removal and gradual cooling of the flue gas; wherein, the liquid-to-gas ratio in the upper layer of the evaporation and crystallization section of the desulfurization tower 2 is 10L / m³. 3 The temperature of the lower spray layer in the evaporation and crystallization section of desulfurization tower 2 is ≤55℃;

[0070] S2.3: The ammonium sulfate rich solution in the lower layer of the evaporation and crystallization section of desulfurization tower 2 flows into the ammonium sulfate receiving tank 11 in the ammonium sulfate circulation tank 5. The ammonium sulfate receiving tank 11 is used to control the temperature of the ammonium sulfate rich solution. Specifically, the ammonium sulfate receiving tank 11 receives the ammonium sulfate rich solution from the lower layer of the evaporation and crystallization section of desulfurization tower 2 at a stirring rate of 100 r / min. The ammonium sulfate pre-separation tank 8, at a stirring rate of 60 r / min and an ammonium sulfate solid content ≥15%, transports the ammonium sulfate solid to the centrifuge for separation via the solid transfer pump 4. The ammonium sulfate transfer tank 9, at a stirring rate of 80 r / min and an ammonium sulfate solid content ≤10%, transports the ammonium sulfate lean solution to the upper spray layer of the evaporation and crystallization section of desulfurization tower 2 via the lean solution circulation pump 7, so as to achieve the evaporation of solvent from the ammonium sulfate lean solution, the nucleation and growth of ammonium sulfate crystals to ammonium sulfate grains ≥120 mesh.

[0071] S2.4: The flow rate of ammonium sulfate lean solution is adjusted by frequency conversion of the lean solution circulation pump 7 to control the temperature of the upper spray layer of the evaporation and crystallization section of the desulfurization tower 2, thereby achieving appropriate growth of ammonium sulfate crystals.

[0072] Step S3: Absorption coupled with oxidation to improve absorption efficiency and oxidation depth;

[0073] Air is introduced into the absorbent receiving layer of the preliminary oxidation section of desulfurization tower 2 to initially oxidize ammonium sulfite. The liquid phase flows into the oxidation section of desulfurization tower 2, while the gas phase mixes with the dust-removing and cooling sulfur-containing flue gas and then flows countercurrently into the absorption coupled oxidation section of desulfurization tower 2, contacting the absorbent (liquid ammonia and dilute ammonium sulfate solution). The temperature of the dust-removing and cooling sulfur-containing flue gas is ≤55℃, and the liquid-to-gas ratio in the absorption coupled oxidation section of desulfurization tower 2 is 12L / m³. 3The spray layer temperature of the absorption coupled oxidation section of desulfurization tower 2 is ≤50℃, and the pH of the absorption liquid is 5~8, thereby realizing the deep absorption of sulfur dioxide and the deep oxidation of ammonium sulfite, i.e., the absorption coupled oxidation process. This process promotes the oxidation of the absorption product ammonium sulfite, improves the absorption efficiency of sulfur dioxide, and reduces the oxidation load of the oxidation section. Finally, the washing and demisting section of desulfurization tower 2 achieves the goal of achieving the emission standards for sulfur dioxide in the tail gas, ammonia escape, and effective control of aerosols.

[0074] Secondly, this utility model provides an energy-saving ammonia desulfurization device, which is mainly used to realize the energy-saving ammonia desulfurization process of ammonium sulfate upgrading and efficiency improvement provided in the first aspect of this utility model.

[0075] See Figure 1 As described above, this utility model provides an energy-saving ammonia desulfurization device, which specifically includes the following components:

[0076] The system includes: 1. Oxidation mixed gas preheater; 2. Desulfurization tower; 3. Absorbent liquid circulation pump; 4. Solid transfer pump; 5. Ammonium sulfate circulation tank; 6. Wastewater circulation pump; 7. Lean liquid circulation pump; 8. Ammonium sulfate pre-separation tank; 9. Ammonium sulfate transfer tank; 10. Wastewater collection tank; and 11. Ammonium sulfate receiving tank.

[0077] The oxidizing mixed gas preheater 1, absorbent circulation pump 3, ammonium sulfate circulation tank 5, wastewater circulation pump 6, and lean liquor circulation pump 7 are all connected to the desulfurization tower 2. The ammonium sulfate circulation tank 5 consists of an ammonium sulfate receiving tank 11, an ammonium sulfate pre-separation tank 8, and an ammonium sulfate conveying tank 9. The ammonium sulfate receiving tank 11 is connected to both the ammonium sulfate pre-separation tank 8 and the ammonium sulfate conveying tank 9. The ammonium sulfate receiving tank 11 is connected to the desulfurization tower 2. The wastewater collection tank 10 is connected to both the ammonium sulfate circulation tank 5 and the wastewater circulation pump 6. Specifically, the wastewater collection tank 10 is connected to the ammonium sulfate conveying tank 9. The lean liquor circulation pump 7 is connected to the ammonium sulfate circulation tank 5. Specifically, the lean liquor circulation pump 7 is connected to the ammonium sulfate conveying tank 9. The solids conveying pump 4 is connected to the ammonium sulfate circulation tank 5. Specifically, the solids conveying pump 4 is connected to the ammonium sulfate pre-separation tank 8.

[0078] In this embodiment, the desulfurization tower 2 is arranged from top to bottom as follows: a washing and demisting section, an absorption coupled oxidation section, a preliminary oxidation section, an evaporation and crystallization section, and an oxidation section. The evaporation and crystallization section is further divided into an upper layer and a lower layer.

[0079] Specifically, the washing and demisting section of desulfurization tower 2 is connected to an external liquid ammonia source and an absorbent circulation pump 3, which provides liquid ammonia and dilute ammonium sulfate solution as absorbent to the absorption-coupled oxidation section of desulfurization tower 2; the preliminary oxidation section of desulfurization tower 2 is connected to an external air source and a lean solution circulation pump 7, which is connected to an ammonium sulfate conveying tank 9, for introducing air into the preliminary oxidation section of desulfurization tower 2 and introducing lean ammonium sulfate solution into the evaporation and crystallization section of desulfurization tower 2; the preliminary oxidation section of desulfurization tower 2 is connected to the oxidation section of desulfurization tower 2, for conveying the pre-oxidized ammonium sulfate liquid to the oxidation section of desulfurization tower 2 for relay oxidation; sulfur dioxide-containing flue gas is introduced into both the upper and lower layers of the evaporation and crystallization section of desulfurization tower 2; at the same time, the upper layer of the evaporation and crystallization section of desulfurization tower 2 is connected to a wastewater circulation pump 6, which is connected to a wastewater collection tank 10, for introducing centrifuge wastewater and high ammonia nitrogen wastewater into the lower layer of the evaporation and crystallization section of desulfurization tower 2; waste Water collection tank 10 is connected to ammonium sulfate conveying tank 9, and is used to replenish centrifuge wastewater and high ammonia nitrogen wastewater to ammonium sulfate conveying tank 9 to adjust the liquid level of ammonium sulfate conveying tank 9; the lower layer of the evaporation and crystallization section of desulfurization tower 2 is connected to absorbent circulation pump 3 and ammonium sulfate receiving tank 11 respectively, and is used to introduce absorbent into the oxidation section of desulfurization tower 2, and to spray absorbent into the middle layer of evaporation and crystallization section in a metered manner to maintain the liquid level of ammonium sulfate conveying tank 9 and ensure the normal operation of lean liquid circulation pump 7; at the same time, rich ammonium sulfate solution is introduced into ammonium sulfate receiving tank 11; the oxidation section of desulfurization tower 2 is connected to the primary oxidation section of desulfurization tower 2, oxidation mixed gas preheater 1 and absorbent circulation pump 3 respectively, and is used to premix flue gas containing sulfur dioxide with air and enter the oxidation section of desulfurization tower 2 after auxiliary heating by oxidation mixed gas preheater 1, and to carry out dust removal and deep oxidation of ammonium sulfite in the oxidation section of desulfurization tower 2.

[0080] Specifically, the ammonium sulfate circulation tank 5 consists of an ammonium sulfate receiving tank 11, an ammonium sulfate pre-separation tank 8, and an ammonium sulfate conveying tank 9. The ammonium sulfate receiving tank 11 is connected to both the ammonium sulfate pre-separation tank 8 and the ammonium sulfate conveying tank 9. The ammonium sulfate receiving tank 11 is equipped with sparse tubes for temperature control. The bottom of the ammonium sulfate receiving tank 11 is connected to the bottom of the ammonium sulfate pre-separation tank 8 to achieve pre-separation of ammonium sulfate solids and control the ammonium sulfate solid content in the ammonium sulfate lean solution. The tops of the ammonium sulfate receiving tank 11 and the ammonium sulfate conveying tank 9 are connected to convey the ammonium sulfate lean solution by overflow.

[0081] Specifically, the solid transfer pump 4 is connected to the ammonium sulfate pre-separation tank 8 and is used to transport the ammonium sulfate solid in the ammonium sulfate pre-separation tank 8 to the centrifuge for separation (to the centrifuge).

[0082] This utility model discloses an energy-saving ammonia desulfurization device. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this utility model. The product of this utility model has been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the product described herein without departing from the content, spirit, and scope of this utility model to realize and apply the technology of this utility model.

Claims

1. An energy-saving ammonia-based desulfurization device, characterized in that, include: The desulfurization tower (2) has, from top to bottom, a washing and demisting section, an absorption coupled oxidation section, a preliminary oxidation section, an evaporation and crystallization section, and an oxidation section; the evaporation and crystallization section is divided into an upper layer and a lower layer. An oxidation mixed gas preheater (1) is connected to the oxidation section of the desulfurization tower (2); Absorbent circulation pumps (3) are respectively connected to the oxidation section, the lower layer of the evaporation crystallization section and the washing and demisting section of the desulfurization tower (2); Ammonium sulfate circulation tank (5) is connected to the lower layer of the evaporation and crystallization section of the desulfurization tower (2); Wastewater circulation pump (6) connected to the upper layer of the evaporation and crystallization section of the desulfurization tower (2); Lean liquor circulation pump (7) is connected to the preliminary oxidation section of the desulfurization tower (2) and the ammonium sulfate circulation tank (5), respectively; Wastewater collection tank (10) is connected to ammonium sulfate circulation tank (5) and wastewater circulation pump (6) respectively.

2. The energy-saving ammonia desulfurization device according to claim 1, characterized in that, The ammonium sulfate circulation tank (5) consists of an ammonium sulfate receiving tank (11), an ammonium sulfate pre-separation tank (8), and an ammonium sulfate conveying tank (9); the ammonium sulfate receiving tank (11) is connected to the ammonium sulfate pre-separation tank (8) and the ammonium sulfate conveying tank (9) respectively; the ammonium sulfate receiving tank (11) is connected to the lower layer of the evaporation and crystallization section of the desulfurization tower (2); the wastewater collection tank (10) and the lean liquid circulation pump (7) are connected to the ammonium sulfate conveying tank (9) respectively.

3. The energy-saving ammonia desulfurization device according to claim 2, characterized in that, The ammonium sulfate receiving tank (11) is equipped with sparse tubes inside.

4. The energy-saving ammonia desulfurization device according to claim 2, characterized in that, The ammonium sulfate receiving tank (11) is connected to the bottom of the ammonium sulfate pre-separation tank (8) to achieve the pre-separation of ammonium sulfate solids.

5. An energy-saving ammonia desulfurization device according to claim 2, characterized in that, The ammonium sulfate receiving tank (11) is connected to the top of the ammonium sulfate conveying tank (9) to convey the ammonium sulfate lean solution by overflow.

6. An energy-saving ammonia desulfurization device according to claim 2, characterized in that, It also includes a solids transfer pump (4) connected to the ammonium sulfate pre-separation tank (8).

7. The energy-saving ammonia desulfurization device according to claim 1, characterized in that, The washing and demisting section of the desulfurization tower (2) is connected to an external liquid ammonia source.

8. The energy-saving ammonia desulfurization device according to claim 1, characterized in that, The initial oxidation section of the desulfurization tower (2) is connected to an external air source.

9. The energy-saving ammonia desulfurization device according to claim 1, characterized in that, The upper and lower layers of the evaporation and crystallization section of the desulfurization tower (2) are both vented with flue gas containing sulfur dioxide.

10. An energy-saving ammonia desulfurization device according to claim 1, characterized in that, The preliminary oxidation section of the desulfurization tower (2) is connected to the oxidation section.

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