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CN-122006440-A - Ammonia desulfurization system and method based on partition control

CN122006440ACN 122006440 ACN122006440 ACN 122006440ACN-122006440-A

Abstract

The invention discloses an ammonia desulfurization system and method based on partition control, comprising a desulfurization tower, an absorption circulation tank, an ammonia water tank, a water washing tank and a process water tank. The desulfurizing tower is sequentially provided with a flue gas outlet, a demisting section, a second section of absorption layer, a first section of absorption layer and a concentrating section from top to bottom. A partition plate is arranged in the absorption circulation tank to divide the absorption circulation tank into an upper oxidation tank and a lower absorption circulation section. The lower part is communicated with the inlet of the first section of absorption layer, the upper oxidation tank is internally provided with an aeration pipe and is connected with the spraying liquid inlet of the second section of absorption layer through a pipeline, and the concentration section at the lower part of the desulfurizing tower is connected with the oxidation tank through a transfusion pipeline. The water washing tank supplies water to the demisting section and the absorption circulating tank, the ammonia water tank supplements ammonia water to the oxidation tank, the first-stage absorption layer and the lower absorption circulating section respectively, and the demisting section recovery liquid is connected back to the water washing tank through a pipeline. The invention eliminates coupling interference of absorption and oxidation by the same groove partition, and effectively controls ammonia escape while ensuring high-efficiency removal of sulfur dioxide by matching with two-stage absorption and demisting recovery.

Inventors

  • ZENG ZIPING
  • LI BINGBING
  • ZHOU XIFEI
  • ZENG YIJUN

Assignees

  • 亚太环保股份有限公司

Dates

Publication Date
20260512
Application Date
20260401

Claims (10)

  1. 1. The ammonia desulfurization system based on zone control comprises a desulfurization tower (1-2), an absorption circulation tank (1-10), an ammonia water tank (1-12), a water washing tank (1-13) and a process water tank (1-14), wherein the desulfurization tower (1-2) is sequentially provided with a flue gas outlet (1-7), a demisting section (1-6), a two-section absorption section (1-5), a one-section absorption section (1-4) and a concentration section (1-3) from top to bottom, the concentration section (1-3) is provided with a flue gas inlet (1-1), and the process water tank (1-14) is used for providing flushing desalted water (1-8) for the demisting section (1-6), and is characterized in that: A baffle plate is arranged in the absorption circulation tank (1-10), and the upper part of the absorption circulation tank (1-10) is divided into an oxidation tank (1-9); An aeration pipe (1-11) is arranged in the oxidation tank (1-9); the oxidation tank (1-9) is connected with a spraying liquid inlet of the two-stage absorption tank (1-5) through a pipeline; the lower concentration section of the desulfurizing tower (1-2) is connected with the oxidation tank (1-9) through a transfusion pipeline; the water washing tank (1-13) is used for respectively providing flushing desalted water for the demisting sections (1-6) and supplementing water for the absorption circulation tank (1-10); The ammonia water tank (1-12) is used for respectively supplying ammonia water to the lower parts of the oxidation tank (1-9), the first-stage absorption tank (1-4) and the absorption circulation tank (1-10); the recovery liquid of the demisting section (1-6) is connected with the water washing tank (1-13) through a pipeline; the recovery liquid of the first section of absorption (1-4) is connected with the lower part of the absorption circulation tank (1-10) through a pipeline; the recovery liquid of the two-stage absorption (1-5) is connected with the oxidation tank (1-9) through a pipeline.
  2. 2. The ammonia desulfurization system based on zone control according to claim 1, wherein the ammonia water tank (1-12) is provided with a two-stage absorption ammonia adding regulating valve (2-5) on a liquid supply pipeline from the ammonia water tank (1-12) to the oxidation tank (1-9).
  3. 3. The ammonia desulfurization system based on zone control according to claim 1 or 2, wherein the ammonia water tank (1-12) is provided with a micro-control ammonia adding regulating valve (2-4) on a liquid supply pipeline of one section of absorption (1-4).
  4. 4. The ammonia desulfurization system based on zone control according to claim 1 or 2, wherein a main regulating and controlling ammonia adding regulating valve (2-3) is arranged on a liquid supply pipeline from the ammonia water tank (1-12) to the absorption circulation tank (1-10).
  5. 5. The ammonia desulfurization system based on zone control according to claim 1 or 2, wherein a pH meter (2-7) is arranged on a connecting pipeline of the oxidation tank (1-9) and the two-stage absorption tank (1-5).
  6. 6. The ammonia desulfurization system based on zone control according to claim 1 or 2, wherein an ammonia adding flowmeter (2-6) is arranged at the liquid outlet of the ammonia water tank (1-12).
  7. 7. The ammonia desulfurization system based on zone control according to claim 1 or 2, wherein a flue gas inlet CEMS (2-1) is arranged at the flue gas inlet (1-1), and a flue gas outlet CEMS (2-2) is arranged at the flue gas outlet (1-7).
  8. 8. The ammonia desulfurization system based on zone control of claim 1 is characterized in that the first-stage absorption (1-4) is provided with two-five spraying layers, one spraying layer can be combined with a high specific area filler layer, the second-stage absorption (1-5) is provided with 1-3 spraying layers, and the single-layer coverage rate of each spraying layer is more than or equal to 300%.
  9. 9. The ammonia desulfurization system based on zone control according to claim 1, wherein the lower absorption circulation tank (1-10) is provided with a pH monitoring and controlling unit for controlling the pH value of the absorption liquid to 5.5-7.0, and the upper oxidation tank (1-9) is provided with an independent pH monitoring and controlling unit for controlling the pH value of the oxidation liquid to 3.5-5.5.
  10. 10. An ammonia desulfurization method based on zone control, which is characterized by adopting the system as claimed in any one of claims 1-9, and comprises the following steps: The sulfur-containing flue gas enters a desulfurizing tower (1-2) through a flue gas inlet, and the sulfur dioxide in the flue gas is fully absorbed through a first-stage absorption (1-4) and a second-stage absorption (1-5) in sequence, so that a desulfurizing effect is achieved; The method comprises the steps of mixing one section of absorption (1-4) after absorbing SO 2 , leading the mixture to flow into the bottom of an absorption circulation tank (1-10), pressurizing one section of absorption liquid by an absorption pump, then sending the absorption liquid into one section of absorption section of a desulfurizing tower (1-2), continuously circulating, spraying and countercurrent absorbing SO 2 , and overflowing the other section of absorption liquid into an oxidation tank (1-9) under the action of pressure difference, wherein along with the progress of the absorption process, (NH 4 ) 2 SO 3 absorbs SO 2 to form NH 4 HSO 3 , and an absorbent which is constantly supplemented with NH 3 , SO that NH 4 HSO 3 is converted into (NH 4 ) 2 SO 3 ; Taking liquid from the oxidation tank in the second-stage absorption (1-5), deeply absorbing residual SO 2 in the flue gas by using ammonium sulfite which is not oxidized in the liquid in the oxidation tank, converting NH 4 HSO 3 into (NH 4 ) 2 SO, increasing absorption rate and oxidation rate and reducing ammonia escape) by using residual free ammonia or adding ammonia water in the second-stage absorption reflux, and returning the absorption liquid to the oxidation tank (1-9) to be close to the upper part of the aeration pipe (1-11) for oxidation treatment; The oxidation tank (1-9) ensures that the subtaline is fully oxidized by controlling the reasonable residence time, aeration intensity, aeration height and pH value to 3.5-5.5, the pH value of an absorption area is controlled to 5.5-7.0, the absorption circulation tank (1-10) and a tank partition board are partitioned, the bottom is an absorption area, the upper part is an oxidation area, the absorption and oxidation processes are not interfered with each other, the absorption liquid absorbed by one section (1-4) is not oxidized, the absorption efficiency is improved, and the ammonia escape is reduced; the flue gas after two sections of absorption is discharged after ammonia removal treatment through a combined demisting section (1-6).

Description

Ammonia desulfurization system and method based on partition control Technical Field The invention relates to the technical field of flue gas treatment, in particular to an ammonia desulfurization system and method based on partition control. Background The ammonia desulfurization technology is used as a typical recycling flue gas purification technology, and is widely applied to flue gas treatment in the fields of coal-fired boilers, industrial kilns and the like due to the advantages of high desulfurization efficiency, recycling of byproduct ammonium sulfate and the like. The conventional ammonia desulfurization process mostly adopts the configuration of separating an absorption tower from an oxidation tank, or is arranged in the same container but has an undefined functional partition. This design results in a high degree of mixing of the absorption and oxidation fluids within the system, which contradicts the optimal process environment required for the two critical reaction stages, the absorption process requires a weakly alkaline environment to maintain the high absorption activity of ammonium sulfite, and the oxidation process requires an acidic environment to promote efficient oxidation of ammonium bisulfate. In the traditional process, due to the lack of effective physical isolation or flow field control, oxidized air easily enters an absorption zone prematurely, and ammonium sulfite serving as a key absorption medium is partially oxidized, so that the effective concentration and absorption capacity of the ammonium sulfite are reduced, otherwise, if a large amount of alkaline substances in the absorption zone enter an oxidation zone, the oxidation reaction rate is inhibited, so that ammonium bisulfate is accumulated, and the incomplete oxidation is caused. The mutual restriction and interference of the absorption and oxidation environment makes it difficult for the system to simultaneously maintain high desulfurization efficiency and high oxidation rate, and becomes a key factor for restricting the improvement of the performance of the traditional ammonia desulfurization process. In terms of emission control, the prior art faces serious challenges in ammonia slip and aerosol problems. In a local area in the absorption tower, particularly when the pH control is poor or the mixing is uneven, gas-gas reaction of gas-phase ammonia and SO 2 easily occurs to generate ammonium sulfite/ammonium sulfate aerosol. Such submicron aerosols are difficult to effectively capture by conventional mist eliminators (e.g., baffles, wire mesh mist eliminators). Although the demister structure is improved in some patents, the demister structure has low pertinence to aerosol of chemical origin, so that the ammonia escape concentration often exceeds 5mg/Nm3, blue smoke visual pollution is easy to form, and the existing ultra-low ammonia escape control requirement cannot be met. Meanwhile, in order to achieve stricter particulate matter emission standard, the system resistance is obviously increased by simply depending on increasing the density or the stage number of the demister, so that the operation energy consumption is increased Therefore, how to overcome the coupling interference of the absorption and oxidation processes, realize the separate optimization of the reaction environment, and the insufficient control effects of ammonia escape and aerosol, and hardly meet the ultra-low SO 2, particulate matters and ammonia escape limit value at the same time, and the energy consumption, the operation stability and the self-adaptive control capability of the system are to be improved, which is a technical problem to be solved in the technical field of the current ammonia desulfurization. Disclosure of Invention The invention aims to provide an ammonia desulfurization system and an ammonia desulfurization method based on partition control. In order to solve the technical problems, the technical scheme of the invention is as follows: The ammonia desulfurization system based on zone control comprises a desulfurization tower, an absorption circulation tank, an ammonia water tank, a washing tank and a process water tank, wherein the desulfurization tower is sequentially provided with a flue gas outlet, a demisting section, a two-section absorption section, a one-section absorption section and a concentration section from top to bottom, and a flue gas inlet is arranged at the concentration section; A baffle plate is arranged in the absorption circulation tank to divide the upper part of the absorption circulation tank into an oxidation tank; an aerator pipe is arranged in the oxidation tank; the oxidation tank is connected with a spraying liquid inlet of the two-stage absorption through a pipeline; The lower concentration section of the desulfurizing tower is connected with the oxidation tank through a transfusion pipeline; The washing tank is used for respectively providing washing desalted water for the demisting sections and su