Oxidation-inhibited wet desulfurization synergist and wet flue gas desulfurization system

Abstract

The invention discloses an oxidation-inhibited wet desulfurization synergist and a wet flue gas desulfurization system, the oxidation-inhibited wet desulfurization synergist comprises a pH buffer agent and an oxidation inhibitor, the dosage of the synergist is small, and the desulfurization efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of wet flue gas desulfurization, and relates to an oxidation-inhibiting wet desulfurization synergist and a wet flue gas desulfurization system. Background Art

[0002] To alleviate SO x To prevent air pollution caused by flue gas, flue gas needs to be desulfurized before emission. Wet flue gas desulfurization technology is the most widely used due to its high operating stability, high efficiency and rich experience. Limestone / lime is widely used in wet flue gas desulfurization (FGD) process due to its relatively low price. However, with the increasingly stringent environmental standards and the gradual decline of coal quality, coal gas desulfurization devices are facing more and more challenges.

[0003] One solution is to add a synergist to the desulfurized lime slurry to increase the desulfurization efficiency by increasing the liquid phase and gas-liquid mass transfer coefficients and improving the pH buffering capacity of the slurry. Wet desulfurization synergist is an additive used to improve the efficiency and effect of wet limestone flue gas desulfurization systems. It improves desulfurization efficiency by increasing the limestone dissolution rate and SO2 absorption rate, as well as catalytic oxidation, to increase the oxidation rate of calcium sulfite, thereby improving the wet desulfurization efficiency. Energy saving and consumption reduction: Increase the gas-liquid mass transfer rate of sulfur dioxide, reduce gas phase resistance, and promote SO2 absorption. Reduce the liquid-gas ratio required by the system and reduce the power consumption rate of the desulfurization system.

[0004] Studies have shown that synergists can improve the reactivity of limestone, reduce its dissolution resistance, improve the dissolution and diffusion of SO2, and make the pH value of the desulfurization slurry more stable. Desulfurization synergists can be divided into organic synergists or inorganic synergists according to their different mechanisms. Organic synergists mainly include acids such as benzoic acid, adipic acid, formic acid, acetic acid and citric acid, which have a pH buffering effect, while inorganic additives are mainly sodium salts, ammonium salts and magnesium compounds. Due to the ability of organic additives to buffer pH and improve the crystal growth of gypsum, they are widely used in power plants and significantly improve the desulfurization efficiency.

[0005] However, organic synergists are generally highly volatile and are easily discharged into the flue gas during the spraying and washing process in the absorption tower. Inorganic synergists react quickly and can quickly improve the desulfurization efficiency, but the duration is short and they are consumable additives. In addition, these synergists may co-precipitate during the precipitation of CaSO3 / CaSO4 and be entrained in the desulfurization solid product. On the one hand, it will cause the loss of synergists and increase the operating costs. On the other hand, it may affect the quality of the finished gypsum. If it is landfilled, it may further pollute the water and soil. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an oxidation-inhibited wet desulfurization synergist and a wet flue gas desulfurization system, wherein the dosage of the synergist is small and the desulfurization efficiency is high.

[0007] To achieve the above object, the present invention discloses an oxidation-inhibited wet desulfurization synergist, comprising a pH buffer and an oxidation inhibitor.

[0008] The further improvement of the oxidation-inhibited wet desulfurization synergist of the present invention is:

[0009] Furthermore, the pH buffer includes but is not limited to formates, benzoates and adipates.

[0010] Furthermore, the oxidation inhibitor is thiosulfate.

[0011] Furthermore, a solubilizing agent is also included.

[0012] Furthermore, the solubilizing agent includes but is not limited to: magnesium salt, sodium salt and ammonium salt.

[0013] Furthermore, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is (10-100):(10-200):(10-1000).

[0014] The invention discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein slurry in a slurry pool in the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0015] The further improvement of the wet flue gas desulfurization system of the present invention is:

[0016] Furthermore, the oxidation-inhibiting wet desulfurization synergist also includes a solubilizing agent.

[0017] Furthermore, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is (10-100):(10-200):(10-1000).

[0018] Further, the pH buffer includes but is not limited to: formates, benzoates and adipates;

[0019] The oxidation inhibitor is thiosulfate.

[0020] The present invention has the following beneficial effects:

[0021] The oxidation-inhibited wet desulfurization synergist and wet flue gas desulfurization system of the present invention are used to add oxidation inhibitors during specific operation to reduce SO3 2-The oxidation ratio of ions is reduced, thereby reducing the possibility of CaSO4·2H2O precipitation and crystallization during the desulfurization tower spraying process, fundamentally solving the scaling problem in the flue of the desulfurization tower, with less usage and higher desulfurization efficiency.

[0022] Furthermore, it also includes a solubilizer, which is used to increase the SO3 2- and SO4 2- Ion concentration additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 Structural diagram of the wet flue gas desulfurization system of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0029] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0030] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0033] The oxidation-inhibited wet desulfurization synergist of the present invention comprises a pH buffer and an oxidation inhibitor.

[0034] As an embodiment of the present invention, the pH buffer includes but is not limited to: formates, benzoates and adipates.

[0035] As an embodiment of the present invention, the oxidation inhibitor is thiosulfate, or a substance added to the system that can form thiosulfate, for example, elemental sulfur.

[0036] As an embodiment of the present invention, the oxidation-inhibited wet desulfurization synergist further includes a solubilizing agent.

[0037] As an embodiment of the present invention, the solubilizing agent is to increase the SO3 2- and SO4 2- The additives for increasing ion concentration are mainly inorganic additives, and the solubilizers include but are not limited to: magnesium salts, sodium salts and ammonium salts.

[0038] As an embodiment of the present invention, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is (10-100): (10-200): (10-1000).

[0039] Correspondingly, the present invention discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0040] Confirmatory trials

[0041] The oxidation-inhibited wet desulfurization synergist described in this test includes a pH buffer, a solubilizing agent and an oxidation inhibitor, wherein the pH buffer is sodium formate HCOONa, the solubilizing agent is magnesium oxide MgO, and the oxidation inhibitor is sodium thiosulfate Na2S2O3, and the formula thereof is shown in Table 1.

[0042] Table 1

[0043]

[0044]

[0045] use Figure 1 The device shown tests the effect of desulfurization synergist, simulating a flue gas flow of 5m 3 / h, the flue gas composition is shown in Table 2, containing 5000ppm SO2. The limestone concentration in the lime slurry is 5g / L, the pH is about 5-6, and the configured desulfurization synergist is added. After the test starts, the flue gas enters the desulfurization tower from the bottom, and the desulfurized lime slurry is pumped into the desulfurization tower through the slurry pump, sprayed down from the top, and contacted with the flue gas in reverse. The desulfurized flue gas leaves the desulfurization tower from the top, and the lime slurry is recovered back to the slurry pool.

[0046] Table 2

[0047] Smoke composition <![CDATA[SO2]]> <![CDATA[O2]]> <![CDATA[CO2]]> <![CDATA[N2]]> Content (vol%) 0.5 6 14 Balance gas

[0048] 60 minutes after the test started, the SO2 concentration at the flue gas outlet was recorded to determine the desulfurization efficiency. The water sample in the slurry pool was taken, and the liquid and solid phase components were determined after solid-liquid separation. The test results are shown in Table 3.

[0049] Table 3

[0050]

[0051] From the test results in Table 3, it can be seen that the desulfurization efficiency of Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 has been significantly improved. Comparative Example 1 is the case where no desulfurization synergist is added, and the desulfurization efficiency is the lowest. In Comparative Example 2, only sodium formate is added. Although the desulfurization efficiency is improved, the HCOO in the liquid phase after 60 minutes of testing is - The concentration dropped a lot, which is due to the Ca 2+ Higher concentrations result in the loss of calcium formate HCOOCa by co-precipitation with CaSO4.

[0052] In Example 1, sodium formate and sodium thiosulfate were added, and thiosulfate S2O3 2- Can limit SO3 2- To SO4 2- The oxidation process reduces the possibility of CaSO4 precipitation and reduces the loss of formate to 1 / 4. In Example 2, adding the solubilizing agent MgO can increase SO4 2- and SO3 2- The solubility of Ca 2- In Example 3, three desulfurization synergistic ingredients, sodium formate, oxidase and sodium thiosulfate, were added simultaneously, and the desulfurization efficiency was the highest.

[0053] It should be noted that the present invention has the following characteristics:

[0054] The present invention adds an oxidation inhibitor to make SO3 2- The oxidation ratio of ions is reduced, thereby reducing the possibility of CaSO4·2H2O precipitation and crystallization during the desulfurization tower spraying process, fundamentally solving the scaling problem in the desulfurization tower flue.

[0055] The present invention reduces the possibility of co-precipitation of other components (pH regulator, surfactant, catalyst, etc.) in the synergist with CaSO4, reduces the loss of the synergist during the desulfurization process, and thus reduces the operating cost of wet desulfurization.

[0056] Embodiment 4

[0057] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a pH buffer and an oxidation inhibitor.

[0058] The pH buffers described in this embodiment include formates, benzoates and adipates.

[0059] The oxidation inhibitor in this embodiment is thiosulfate.

[0060] Accordingly, this embodiment discloses a wet flue gas desulfurization system, including an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0061] Embodiment 5

[0062] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a pH buffer and an oxidation inhibitor.

[0063] The pH buffers described in this embodiment include benzoate and adipate.

[0064] The oxidation inhibitor in this embodiment is thiosulfate.

[0065] Accordingly, this embodiment discloses a wet flue gas desulfurization system, including an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0066] Embodiment 6

[0067] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a pH buffer and an oxidation inhibitor.

[0068] The pH buffer described in this embodiment includes formate.

[0069] The oxidation inhibitor in this embodiment is thiosulfate.

[0070] Accordingly, this embodiment discloses a wet flue gas desulfurization system, including an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0071] Embodiment 7

[0072] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a pH buffer and an oxidation inhibitor.

[0073] The pH buffer described in this embodiment includes benzoate.

[0074] The oxidation inhibitor in this embodiment is thiosulfate.

[0075] Accordingly, this embodiment discloses a wet flue gas desulfurization system, including an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0076] Embodiment 8

[0077] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a pH buffer and an oxidation inhibitor.

[0078] The pH buffer described in this embodiment includes adipate.

[0079] The oxidation inhibitor in this embodiment is thiosulfate.

[0080] Accordingly, this embodiment discloses a wet flue gas desulfurization system, including an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with an oxidation-inhibiting wet desulfurization synergist.

[0081] Embodiment 9

[0082] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0083] In this embodiment, the pH buffer includes formate, benzoate and adipate.

[0084] In this embodiment, the oxidation inhibitor is thiosulfate.

[0085] In this embodiment, the solubilizing agent includes magnesium salt, sodium salt and ammonium salt.

[0086] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 10:10:10.

[0087] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0088] Embodiment 10

[0089] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0090] In this embodiment, the pH buffer includes benzoate and adipate.

[0091] In this embodiment, the oxidation inhibitor is thiosulfate.

[0092] In this embodiment, the solubilizing agent includes sodium salt and ammonium salt.

[0093] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 100:200:1000.

[0094] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0095] Embodiment 11

[0096] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0097] In this embodiment, the pH buffer comprises formate.

[0098] In this embodiment, the oxidation inhibitor is thiosulfate.

[0099] In this embodiment, the solubilizing agent includes magnesium salt.

[0100] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 10:200:10.

[0101] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0102] Embodiment 12

[0103] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0104] In this embodiment, the pH buffer comprises benzoate.

[0105] In this embodiment, the oxidation inhibitor is thiosulfate.

[0106] In this embodiment, the solubilizing agent includes sodium salt.

[0107] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 100:10:1000.

[0108] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0109] Embodiment 13

[0110] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0111] In this embodiment, the pH buffer comprises adipate.

[0112] In this embodiment, the oxidation inhibitor is thiosulfate.

[0113] In this embodiment, the solubilizing agent includes ammonium salt.

[0114] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 50:100:100.

[0115] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0116] Embodiment 14

[0117] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0118] In this embodiment, the pH buffer includes formate, benzoate and adipate.

[0119] In this embodiment, the oxidation inhibitor is thiosulfate.

[0120] In this embodiment, the solubilizing agent includes magnesium salt, sodium salt and ammonium salt.

[0121] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 80:110:200.

[0122] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0123] Embodiment 15

[0124] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0125] In this embodiment, the pH buffer includes formate, benzoate and adipate.

[0126] In this embodiment, the oxidation inhibitor is thiosulfate.

[0127] In this embodiment, the solubilizing agent includes magnesium salt, sodium salt and ammonium salt.

[0128] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 20:50:800.

[0129] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0130] Embodiment 16

[0131] This embodiment discloses an oxidation-inhibited wet desulfurization synergist, which includes a solubilizing agent, a pH buffer and an oxidation inhibitor.

[0132] In this embodiment, the pH buffer includes formate, benzoate and adipate.

[0133] In this embodiment, the oxidation inhibitor is thiosulfate.

[0134] In this embodiment, the solubilizing agent includes magnesium salt, sodium salt and ammonium salt.

[0135] In this embodiment, the molar ratio of the pH buffer, the oxidation inhibitor and the solubilizer is 50:150:900.

[0136] This embodiment discloses a wet flue gas desulfurization system, comprising an absorption tower, wherein a wet desulfurization synergist with oxidation inhibition is added to the slurry in the slurry pool of the absorption tower.

[0137] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0138] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0139] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An oxidation-inhibited wet desulfurization synergist, characterized in that: Includes pH buffers and oxidation inhibitors.

2. The oxidation-inhibited wet desulfurization synergist according to claim 1, characterized in that: The pH buffer includes, but is not limited to, formates, benzoates, and adipates.

3. The oxidation-inhibited wet desulfurization synergist according to claim 1, characterized in that: The oxidation inhibitor is thiosulfate.

4. The oxidation-inhibited wet desulfurization synergist according to claim 1, characterized in that: Also included are solubilizing agents.

5. The oxidation-inhibited wet desulfurization synergist according to claim 4, characterized in that: The solubilizing agent includes, but is not limited to, magnesium salt, sodium salt and ammonium salt.

6. The oxidation-inhibited wet desulfurization synergist according to claim 4, characterized in that: The molar ratio of pH buffer, oxidation inhibitor and solubilizer is (10-100):(10-200):(10-1000).

7. A wet flue gas desulfurization system, characterized in that: The invention comprises an absorption tower, wherein the slurry in the slurry pool of the absorption tower is added with the oxidation-inhibiting wet desulfurization synergist according to claim 1.

8. The wet flue gas desulfurization system according to claim 7, characterized in that: The oxidation-inhibiting wet desulfurization synergist also includes a solubilizing agent.

9. The wet flue gas desulfurization system according to claim 7, characterized in that: The molar ratio of pH buffer, oxidation inhibitor and solubilizer is (10-100):(10-200):(10-1000).

10. The wet flue gas desulfurization system according to claim 7, characterized in that: The pH buffering agent includes but is not limited to: formates, benzoates and adipates; The oxidation inhibitor is thiosulfate.

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