A method for adding limestone wet flue gas desulfurization additive

Abstract

The invention discloses a method for adding a limestone wet flue gas desulfurization additive, wherein an additive solution is transported to an absorber slurry circulation pump inlet pipe through an additive adding unit to be mixed with the absorber slurry and then transported to an absorber spray layer through an absorber slurry circulation pump; limestone slurry is transported to an absorber slurry circulation pump inlet pipe through a limestone adding unit to be mixed with the absorber slurry and then transported to an absorber spray layer through an absorber slurry circulation pump; and a mixed solution of the additive solution and the limestone slurry and the absorber slurry is atomized and sprayed to an absorber section / liquid surface / slurry pool through a spray layer. The invention enables the additive to be quickly mixed with the absorber slurry and evenly dispersed into the flue gas and the absorber section / liquid surface / slurry pool, thereby timely eliminating the desulfurization performance impact and resolving the hidden dangers of desulfurization safe operation.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and more particularly to a method for adding a limestone wet flue gas desulfurization additive. Background Art

[0002] In the limestone-gypsum wet flue gas desulfurization process, due to the low quality of limestone, poor quality of process water, high concentration of HF and HCl in the flue gas, the absorber slurry is poisoned, the limestone dissolution rate is low or insoluble, and the absorber slurry foams to produce false liquid levels, which affect the desulfurization performance or safe operation. One of the solutions is to add desulfurization enhancers (or catalysts, co-solvents), defoaming agents and other additives to the absorber from time to time.

[0003] At present, the common method of adding additives is to use the sump system in the absorber area, that is, to add additives to the sump in the absorber area, and directly send the additives to the absorber slurry pool through the sump pump. The main disadvantage of this adding method is that the additives can only be added to one point or a local area of ​​the absorber slurry pool, and the additives are diffused to the entire absorber slurry pool by the flow of the absorber slurry. It takes a long time, and it takes several hours to diffuse the additives to the entire absorber slurry pool, which cannot respond to the desulfurization performance requirements in a timely manner and solve the safety operation hazards in a timely manner. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes a system and method for adding additives to a limestone-gypsum wet flue gas desulfurization process, so that the additives can be quickly mixed with the absorber slurry and evenly dispersed into the flue gas and the absorber section / liquid surface / slurry pool, thereby promptly eliminating the impact on desulfurization performance and solving the hidden dangers of desulfurization safe operation.

[0005] One aspect of the present invention provides a limestone wet flue gas desulfurization additive adding system, comprising an absorption tower, an absorption tower slurry circulation unit, an additive adding unit and a limestone adding unit, wherein the absorption tower slurry circulation unit comprises an absorption tower slurry circulation pump and an absorption tower slurry circulation pump inlet pipe connected to the lower part of the absorption tower and an absorption tower slurry circulation pump outlet pipe connected to the spray layer at the upper part of the absorption tower.

[0006] Wherein, the additive adding unit and the limestone adding unit are respectively connected to the inlet pipeline of the absorption tower slurry circulation pump.

[0007] According to an embodiment of the limestone wet flue gas desulfurization additive addition system of the present invention, the additive addition unit includes an additive solution tank, an additive solution pump and an additive solution pump outlet pipe, and the additive solution tank is connected to the absorption tower slurry circulation pump inlet pipe through the additive solution pump and the additive solution pump outlet pipe.

[0008] According to an embodiment of the limestone wet flue gas desulfurization additive addition system of the present invention, the limestone addition unit includes a limestone slurry tank, a limestone slurry pump and a limestone slurry pump outlet pipe, and the limestone slurry tank is connected to the absorption tower slurry circulation pump inlet pipe through the limestone slurry pump and the limestone slurry pump outlet pipe.

[0009] According to an embodiment of the limestone wet flue gas desulfurization additive addition system of the present invention, the spray layer is provided with several layers of atomizing nozzles, a demister is also provided above the spray layer in the absorption tower, the lower part of the absorption tower is the absorption tower slurry pool, and the flue gas inlet of the absorption tower is located between the spray layer and the absorption tower slurry pool.

[0010] According to an embodiment of the limestone wet flue gas desulfurization additive addition system of the present invention, the additive is a synergist and / or a defoamer, the synergist is at least one of DBA, benzoic acid, acetic acid, formic acid, glutaric acid and succinic acid, and the defoamer is at least one of silicone, ethers, hydrocarbons, alcohols, phosphates and polyethers.

[0011] Another aspect of the present invention discloses a method for adding a limestone wet flue gas desulfurization additive, which uses the above-mentioned limestone wet flue gas desulfurization additive adding system to add the additive.

[0012] According to an embodiment of the limestone wet flue gas desulfurization additive adding method of the present invention, the additive solution is transported to the inlet pipe of the absorber slurry circulation pump through the additive adding unit, mixed with the absorber slurry, and then transported to the absorber spray layer through the absorber slurry circulation pump;

[0013] The limestone slurry is transported to the absorption tower through the limestone adding unit, and then mixed with the absorption tower slurry through the absorption tower slurry circulating pump to the absorption tower spray layer;

[0014] The mixed solution of the additive solution, limestone slurry and absorption tower slurry is then atomized and sprayed into the absorption tower section / liquid surface / slurry pool through the spray layer.

[0015] Another aspect of the present invention discloses a method for adding limestone wet flue gas desulfurization additives, wherein the additive solution and limestone slurry are mixed with the circulated absorber slurry and then returned to the absorber and atomized and sprayed onto the absorber section / liquid surface / slurry pool.

[0016] According to an embodiment of the method for adding additives to limestone wet flue gas desulfurization of the present invention, the additive is a synergist and / or a defoamer, the synergist is at least one of DBA, benzoic acid, acetic acid, formic acid, glutaric acid and succinic acid, and the defoamer is at least one of silicone, ethers, hydrocarbons, alcohols, phosphates and polyethers.

[0017] Compared with the prior art, the present invention can quickly and evenly deliver additives into the absorption tower section / liquid surface / slurry pool, timely solve and eliminate the absorption tower slurry poisoning, limestone dissolution difficulties, slurry foaming and other absorption tower desulfurization performance and unsafe operation hazards; and evenly deliver limestone into the absorption tower section, increase the pH value of the absorption tower spray slurry and improve the ability to absorb flue gas SO2, thereby enhancing the desulfurization efficiency of the absorption tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A structural schematic diagram of a limestone wet flue gas desulfurization additive addition system according to an exemplary embodiment of the present invention is shown.

[0019] Description of reference numerals:

[0020] 1-absorption tower, 11-absorption tower slurry pool, 12-spray layer, 13-demister, 2-absorption tower slurry circulation pump, 21-absorption tower slurry circulation pump inlet pipe, 22-absorption tower slurry circulation pump outlet pipe, 3-limestone slurry tank, 31-limestone slurry pump, 311-limestone slurry pump outlet pipe, 4-additive solution tank, 41-additive solution pump, 411-additive solution pump outlet pipe. DETAILED DESCRIPTION

[0021] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0022] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0023] Hereinafter, the limestone wet flue gas desulfurization additive adding system of the present invention will be described in detail.

[0024] Figure 1 A structural schematic diagram of a limestone wet flue gas desulfurization additive addition system according to an exemplary embodiment of the present invention is shown.

[0025] like Figure 1 As shown, according to an exemplary embodiment of the present invention, the limestone wet flue gas desulfurization additive adding system includes an absorption tower 1, an absorption tower slurry circulation unit, an additive adding unit and a limestone adding unit. The absorption tower 1 is a main component of the limestone-gypsum wet flue gas desulfurization, the absorption tower slurry circulation unit realizes the circulation of the absorption tower slurry, the additive adding unit realizes the addition of the additive solution, and the limestone adding unit realizes the addition of the limestone slurry.

[0026] The spray layer 12 in the absorption tower 1 is provided with several layers of atomizing nozzles to achieve atomization and uniform spraying of the liquid. A demister 13 is also provided above the spray layer 12 in the absorption tower 1 to remove droplets in the flue gas after desulfurization. The lower part of the absorption tower 1 is the absorption tower slurry pool 11, and the flue gas inlet of the absorption tower 1 is located between the spray layer 12 and the absorption tower slurry pool 11.

[0027] Specifically, the absorption tower slurry circulation unit includes an absorption tower slurry circulation pump 2, an absorption tower slurry circulation pump inlet pipe 21 connected to the lower part of the absorption tower 1, and an absorption tower slurry circulation pump outlet pipe 22 connected to the spray layer 12 at the upper part of the absorption tower 1. The absorption tower slurry circulation pump 2 sucks out the absorption tower slurry in the absorption tower slurry pool 11 at the lower part of the absorption tower 1 through the absorption tower slurry circulation pump inlet pipe 21 and returns it through the absorption tower slurry circulation pump outlet pipe 22.

[0028] The additive adding unit and limestone adding unit of the present invention are respectively connected to the inlet pipe 21 of the absorption tower slurry circulation pump, so that the additive solution and the limestone slurry are respectively sent to the inlet pipe 21 of the absorption tower circulation pump to mix with the absorption tower slurry, and the mixed solution is sent to the spray layer 12 of the absorption tower through the absorption tower slurry circulation pump 2, and the mixed solution is atomized into fine droplets through the nozzles arranged in the spray layer 12. On the one hand, the additive is uniformly sprayed into the cross section of the absorption tower and falls with the absorption tower slurry droplets, and is uniformly collected on the absorption tower liquid surface, so that the additive is quickly uniformly dispersed in the absorption tower slurry pool, accelerating the dissolution of limestone, enhancing the desulfurization performance, and eliminating the foam on the absorption tower liquid surface. On the other hand, the pH value of the absorption tower slurry can be increased after the fresh limestone slurry is uniformly sprayed in, and the absorption tower slurry is sent to the spray layer 12 of the absorption tower by the absorption tower slurry circulation pump 2, and is atomized into fine droplets and uniformly sprayed to the absorption tower cross section to contact with the flue gas, thereby improving the desulfurization efficiency.

[0029] Specifically, the additive adding unit of the present invention includes an additive solution tank 4, an additive solution pump 41 and an additive solution pump outlet pipe 411. The additive solution tank 4 is connected to the absorption tower slurry circulation pump inlet pipe 21 through the additive solution pump 41 and the additive solution pump outlet pipe 411. In addition, it can also include a control valve arranged on the additive solution pump outlet pipe 411.

[0030] Similarly, the limestone adding unit of the present invention includes a limestone slurry tank 3, a limestone slurry pump 31 and a limestone slurry pump outlet pipe 311. The limestone slurry tank 3 is connected to the absorption tower slurry circulation pump inlet pipe 21 through the limestone slurry pump 31 and the limestone slurry pump outlet pipe 311. In addition, it can also include a control valve arranged on the limestone slurry pump outlet pipe 311.

[0031] The additives used in the present invention are synergists and / or defoamers, and may also be catalysts, cosolvents, etc. The synergist is a chemical organic acid that reduces the surface tension of limestone slurry droplets, promotes limestone dissolution or / and promotes SO2 absorption, such as at least one of DBA, benzoic acid, acetic acid, formic acid, glutaric acid and succinic acid; the defoamer is an organic substance that eliminates or / and inhibits the foam on the liquid surface of the absorption tower, such as at least one of silicone, ethers, hydrocarbons, alcohols, phosphates and polyethers.

[0032] The method for adding limestone wet flue gas desulfurization additives provided by the present invention can use the above-mentioned limestone wet flue gas desulfurization additive adding system to add additives, and can also use adding systems with other structures but at the same time must meet the additive adding concept of the present invention, that is, the additive solution and limestone slurry are mixed with the circulated absorber slurry and then returned to the absorber and atomized and sprayed into the absorber section / liquid surface / slurry pool, so that the additive and limestone slurry are transported to the absorber spray layer and quickly dispersed into the absorber slurry or contacted and mixed with the flue gas.

[0033] When the adding system of the present invention is adopted, the additive solution is transported to the absorption tower slurry circulation pump inlet pipe 21 through the additive adding unit, mixed with the absorption tower slurry, and then transported to the absorption tower spray layer 12 through the absorption tower slurry circulation pump 2; the limestone slurry is transported to the absorption tower slurry circulation pump inlet pipe 21 through the limestone adding unit, mixed with the absorption tower slurry, and then transported to the absorption tower spray layer 12 through the absorption tower slurry circulation pump 2; and the mixed solution of the additive solution, the limestone slurry and the absorption tower slurry is atomized and sprayed into the absorption tower section / liquid surface / slurry pool through the spray layer 12.

[0034] Among them, similarly, the additive can be a synergist and / or a defoamer, and can also be a catalyst or a cosolvent. The synergist can be at least one of DBA, benzoic acid, acetic acid, formic acid, glutaric acid and succinic acid, and the defoamer can be at least one of silicone, ethers, hydrocarbons, alcohols, phosphates and polyethers.

[0035] The present invention will be further described below in conjunction with the embodiments.

[0036] Embodiment 1:

[0037] An additive solution tank 4 and an additive solution pump 41 are arranged in the absorption tower area. The inlet of the additive solution pump 41 is connected to the additive solution tank 4 , and the additive solution pump outlet pipe 411 is connected to the absorption tower slurry circulation pump inlet pipe 21 of the absorption tower slurry circulation pump 2 .

[0038] The absorption tower slurry circulation pump inlet pipe 21 is connected to the absorption tower slurry pool 11.

[0039] The additive solution is mixed with the absorber circulating slurry, and is sent to the spray layer 12 of the absorber 1 through the absorber slurry circulation pump 2 and the absorber slurry circulation pump outlet pipe 22, and is evenly atomized into the cross-section, slurry pool liquid surface and slurry pool of the absorber 1 through the nozzles on the spray layer 12, so as to promptly solve and eliminate the absorber slurry poisoning, limestone dissolution difficulties, slurry foaming and other impacts on the desulfurization performance of the absorber and the hidden dangers of unsafe operation.

[0040] The limestone slurry in the limestone slurry tank 3 is connected to the absorber slurry circulation pump inlet pipe 21 of the absorber slurry circulation pump 2 through the limestone slurry pump 31 and the limestone slurry pump outlet pipe 311. The limestone slurry is mixed with the absorber circulating slurry, and is sent to the spray layer 12 of the absorber 1 through the absorber slurry circulation pump 2 and the absorber slurry circulation pump outlet pipe 22. It is evenly atomized to the cross section, slurry pool liquid surface and slurry pool of the absorber 1 through the nozzles on the spray layer 12. The limestone slurry can increase the pH value of the absorber spray slurry and improve the ability to absorb flue gas SO2, enhance the desulfurization efficiency of the absorber, and the clean flue gas with flue gas SO2 removed passes through the demister 13 and is discharged from the top or side of the absorber.

[0041] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A method for adding a limestone wet flue gas desulfurization additive, characterized in that: A limestone wet flue gas desulfurization additive adding system is used to add the additive; The limestone wet flue gas desulfurization additive adding system comprises an absorption tower, an absorption tower slurry circulation unit, an additive adding unit and a limestone adding unit. The absorption tower slurry circulation unit comprises an absorption tower slurry circulation pump and an absorption tower slurry circulation pump inlet pipe connected to the lower part of the absorption tower and an absorption tower slurry circulation pump outlet pipe connected to the spray layer at the upper part of the absorption tower. Wherein, the additive adding unit and the limestone adding unit are respectively connected to the inlet pipe of the absorption tower slurry circulation pump; The additive adding unit comprises an additive solution tank, an additive solution pump and an additive solution pump outlet pipe, and the additive solution tank is connected to the absorption tower slurry circulation pump inlet pipe through the additive solution pump and the additive solution pump outlet pipe; The limestone adding unit comprises a limestone slurry tank, a limestone slurry pump and a limestone slurry pump outlet pipe, and the limestone slurry tank is connected to the absorption tower slurry circulation pump inlet pipe through the limestone slurry pump and the limestone slurry pump outlet pipe; The spray layer is provided with several layers of atomizing nozzles, a demister is also provided above the spray layer in the absorption tower, the lower part of the absorption tower is an absorption tower slurry pool, and the flue gas inlet of the absorption tower is located between the spray layer and the absorption tower slurry pool; The additive is a synergist and / or a defoamer, the synergist is at least one of DBA, benzoic acid, acetic acid, formic acid, glutaric acid and succinic acid, and the defoamer is at least one of silicone, ethers, hydrocarbons, alcohols, phosphates and polyethers; The method of adding limestone wet flue gas desulfurization additives is as follows: The additive solution is transported to the inlet pipe of the absorber slurry circulation pump through the additive adding unit, mixed with the absorber slurry, and then transported to the spray layer of the absorber through the absorber slurry circulation pump; The limestone slurry is transported to the absorption tower through the limestone adding unit, and then mixed with the absorption tower slurry through the absorption tower slurry circulating pump to the absorption tower spray layer; The mixed solution of the additive solution, limestone slurry and absorption tower slurry is then atomized and sprayed into the absorption tower section / liquid surface / slurry pool through the spray layer.

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