CN116159413A - Desulfurization system, desulfurization method and application of desulfurization byproducts - Google Patents

Abstract

The present application relates to a desulfurization system comprising: the desulfurizing tower comprises an upper section spraying area, a middle section spraying area, a first slurry collecting area, a lower section spraying area and a second slurry collecting area from top to bottom in sequence, wherein a flue gas inlet is arranged at the lower part of the lower section spraying area, and a flue gas outlet is arranged at the top of the desulfurizing tower; the calcium-based slurry pool is communicated with the upper spray zone through a first pumping mechanism; the red mud liquid pool is communicated with the middle section spraying area through a second pumping mechanism; the circulating pool is communicated with the first slurry collecting area, the circulating pool is also communicated with the upper spraying area through a third pumping mechanism, the circulating pool is also communicated with the middle spraying area through a fourth pumping mechanism, and the circulating pool is also communicated with the lower spraying area through a fifth pumping mechanism; and the sedimentation tank is communicated with the second slurry collecting area. The desulfurization system provided by the application has the effects of low field requirement, low cost and simple process steps.

Description

Desulfurization system, desulfurization method and application of desulfurization byproducts

Technical Field

The application relates to the field of aluminum industry, in particular to comprehensive utilization of red mud.

Background

Red mud is a solid residue discharged in the process of producing alumina by taking bauxite as a raw material in the aluminum industry. 1 to 1.5t of red mud is produced per 1t of alumina produced. At present, the comprehensive utilization rate of the red mud is less than 5%, and the recycling and reduction of the red mud are still difficult and heavy. The main difficulty in influencing the utilization of red mud at present is high alkalinity, the red mud contains a large amount of alkaline chemical substances, the pH value can reach more than 10, the red mud is strong in alkalinity, and the red mud has potential for flue gas desulfurization. The flue gas desulfurization technology which is mature at present comprises three technologies of wet desulfurization, semi-dry desulfurization and dry desulfurization. Among them, the wet desulfurization technology using calcium-based desulfurizing agent as main material has wide application and high technical maturity. The red mud and the flue gas desulfurization are combined, so that the purification treatment problem of the flue gas sulfur dioxide can be solved, the alkalinity of the red mud is further reduced, and a beneficial condition is provided for subsequent reuse.

The application of red mud in flue gas desulfurization at present is often to add a red mud desulfurization step on the basis of the existing wet desulfurization process based on a calcium-based desulfurizing agent, and extra equipment and process steps are often required to be added, so that the cost is high, the site requirement is high, and the implementation is difficult.

Disclosure of Invention

The embodiment of the application provides a desulfurization system, a desulfurization method and application of desulfurization byproducts, so as to solve the technical problems of higher cost and higher field requirement in the application of red mud in flue gas desulfurization.

In a first aspect, embodiments of the present application provide a desulfurization system, the desulfurization system comprising:

the desulfurization tower comprises an upper section spraying area, a middle section spraying area, a first slurry collecting area, a lower section spraying area and a second slurry collecting area from top to bottom in sequence, wherein the liquid in the upper section spraying area and the liquid in the middle section spraying area are converged into the first slurry collecting area, the liquid in the lower section spraying area is converged into the second slurry collecting area, a flue gas inlet is arranged below the lower section spraying area at the lower part of the desulfurization tower, and a flue gas outlet is arranged at the top of the desulfurization tower;

the calcium-based slurry pool is communicated with the upper spray zone through a first pumping mechanism;

the red mud liquid pool is communicated with the middle section spraying area through a second pumping mechanism;

the circulating pool is communicated with the first slurry collecting area, is also communicated with the upper spraying area through a third pumping mechanism, is also communicated with the middle spraying area through a fourth pumping mechanism, and is also communicated with the lower spraying area through a fifth pumping mechanism;

The sedimentation tank is communicated with the second slurry collecting area, and the second slurry collecting area is also communicated with the lower-stage spraying area through a sixth pumping mechanism.

In some embodiments of the present application, the desulfurization system further comprises a solid-liquid separation system in communication with the bottom of the sedimentation tank, the solid-liquid separation system further in communication with the calcium-based slurry tank and the red mud slurry tank.

In some embodiments of the present application, the desulfurization system further comprises an evaporative crystallization system in communication with the solid-liquid separation system, the evaporative crystallization system further in communication with the calcium-based slurry pond and the red mud slurry pond.

In a second aspect, embodiments of the present application provide a desulfurization method, including the steps of:

providing the desulfurization system of any embodiment of the first aspect, introducing sulfur-containing flue gas into the desulfurization system from the flue gas inlet;

introducing the calcium-based slurry in the calcium-based slurry tank into the upper spray zone through the first pumping mechanism;

the red mud slurry in the red mud slurry pond is guided into the middle section spraying area through the second pumping mechanism;

Introducing circulating washing liquid in the circulating pool into the upper-stage spraying area, the middle-stage spraying area and the lower-stage spraying area through the third pumping mechanism, the fourth pumping mechanism and the fifth pumping mechanism respectively;

introducing the slurry in the second slurry collection zone into the settling tank.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

feeding the slurry from the second slurry collection zone into the lower spray zone;

when the pH of the slurry in the second slurry collection zone is below 4.0 or the solid content is greater than 10%, the slurry is introduced into the sedimentation tank until the pH is above 5.3.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

carrying out solid-liquid separation on the slurry in the sedimentation tank to obtain clear liquid and desulfurization byproducts;

preparing the calcium-based slurry in the calcium-based slurry pond by taking a calcium-based desulfurizing agent and the clear liquid as raw materials;

red mud and the clear liquid are used as raw materials to prepare the red mud slurry in the red mud slurry pond.

In some embodiments of the present application, when the sodium sulfate in the supernatant of the sedimentation tank reaches a predetermined concentration, the desulfurization method further comprises the steps of:

Carrying out solid-liquid separation on the slurry in the sedimentation tank to obtain clear liquid and desulfurization byproducts;

evaporating and concentrating the clear liquid to obtain sodium-removing water and crystalline salt;

preparing the calcium-based slurry in the calcium-based slurry pool by taking a calcium-based desulfurizing agent and the sodium removing water as raw materials;

red mud and the sodium removing water are used as raw materials to prepare the red mud slurry in the red mud liquid pool,

wherein the predetermined concentration is 100-220g/L.

In some embodiments of the present application, the calcium-based slurry has a solids content of 4.2% to 14.5%; and/or the number of the groups of groups,

the liquid-solid ratio of the red mud slurry is 30:1-3:1, and the pH value is 7.3-9.8.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

according to the mass of sulfur dioxide in the imported flue gas, adding a desulfurization alkali-reducing accelerator into the circulating pool,

wherein the mass ratio of the desulfurization alkali-reducing accelerant to the sulfur dioxide is 0.05-0.1:1, the desulfurization alkali-reducing accelerant comprises ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon.

In a third aspect, embodiments of the present application provide an application of the desulfurization byproduct, where the desulfurization byproduct is the desulfurization byproduct in the second aspect, and the application of the desulfurization byproduct includes:

10-30 parts of red mud, 10-30 parts of desulfurization byproducts, 2-9 parts of organic biomass, 1-5 parts of farmyard manure, 2-7 parts of ash and 0.5-1 part of microbial fertilizer are mixed by weight and then paved on a red mud storage yard for ecological restoration.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

according to the desulfurization system provided by the embodiment of the application, the sulfur-containing flue gas is leached in the same desulfurization tower by utilizing the calcium-based slurry and the red mud slurry, and the calcium-based slurry and the red mud slurry are used as a circulating pool, so that additional equipment is not needed, the requirements on the site are low, the cost is low, and the process steps are simple and easy to implement.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic structural diagram of a desulfurization system according to an embodiment of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

Unless specifically stated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Thus, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the present specification will control.

Unless specifically indicated otherwise, the various raw materials, reagents, instruments, equipment, and the like used in this application are commercially available or may be prepared by existing methods.

The application of the red mud in flue gas desulfurization at present has the technical problems of higher cost and higher field requirements.

The technical scheme provided by the embodiment of the application aims to solve the technical problems, and the overall thought is as follows:

in a first aspect, embodiments of the present application provide a desulfurization system, the desulfurization system comprising:

the desulfurization tower 1 comprises an upper spray zone 11, a middle spray zone 12, a first slurry collecting zone 13, a lower spray zone 14 and a second slurry collecting zone 15 from top to bottom in sequence, wherein the liquids in the upper spray zone 11 and the middle spray zone 12 are converged into the first slurry collecting zone 13, the liquid in the lower spray zone 14 is converged into the second slurry collecting zone 15, a flue gas inlet 16 is formed in the lower part of the desulfurization tower 1 below the lower spray zone 14, and a flue gas outlet 17 is formed in the top of the desulfurization tower 1;

a calcium-based slurry pool 2 which is communicated with the upper spraying zone 11 through a first pumping mechanism 61;

the red mud liquid pool 3 is communicated with the middle section spraying area 12 through a second pumping mechanism 62;

a circulation tank 4 is communicated with the first slurry collecting area 13, the circulation tank 4 is also communicated with the upper spraying area 11 through a third pumping mechanism 63, the circulation tank 4 is also communicated with the middle spraying area 12 through a fourth pumping mechanism 64, and the circulation tank 4 is also communicated with the lower spraying area 14 through a fifth pumping mechanism 65;

The sedimentation tank 5 is communicated with the second slurry collecting zone 15, and the second slurry collecting zone 15 is also communicated with the lower-stage spraying zone 14 through a sixth pumping mechanism 66.

It will be appreciated by those skilled in the art that the desulfurizing tower 1 is a conventional facility in the art. In this application, the desulfurizing tower 1 has the following working principle: the sulfur-containing flue gas enters the desulfurizing tower 1 from the flue gas inlet 16, continuously moves upwards and is led out from the flue gas outlet 17, in the process, the sulfur-containing flue gas firstly passes through the lower spraying zone 14, and the fifth pumping mechanism 65 pumps the liquid in the circulating pool 4 into the lower spraying zone 14 to rinse the sulfur-containing flue gas; the flue gas then continues to move upwards and passes through the middle spraying zone 12, and the leacheate in the middle spraying zone 12 is pumped from the red mud liquid pool 3 and the circulating pool 4 by the second pumping mechanism 62 and the fourth pumping mechanism 64 respectively; the leacheate from the upper spray zone 11 is pumped from the calcium-based slurry tank 2 and the circulation tank 4 by the first pumping mechanism 61 and the third pumping mechanism 63, respectively.

The pumping mechanism described herein is a mechanism conventional in the art for pumping a liquid, and may be, for example, a mud pump.

It will be appreciated by those skilled in the art that the spray zone described herein is specifically a zone in which a plurality of spray heads are provided and through which liquid is sprayed.

The application first thick liquid collection zone 13, specifically be provided with the region of inclined plane and funnel, upper segment sprays the district 11 and the middle section sprays the district 12 and sprays out liquid entering funnel after the inclined plane drainage, plays the effect of collecting the thick liquid.

The second slurry collecting area 15 is located at the lower part of the desulfurizing tower 1, and the liquid sprayed out from the lower spraying area 14 is naturally accumulated in the second slurry collecting area 15 under the action of gravity.

The calcium-based slurry tank 2 described herein is used to formulate a calcium-based slurry. The calcium-based slurry is formulated with a calcium-based desulfurizing agent and water. The water used to formulate the calcium-based slurry may be industrial tap water or an aqueous solution produced in industrial production that has dissolved solutes that do not affect desulfurization. Among them, the calcium-based desulfurizing agent is a conventional desulfurizing agent in the art, and generally includes at least one of calcium oxide, calcium hydroxide, and calcium carbonate.

The red mud slurry pond 3 is used for preparing red mud slurry. The red mud slurry is prepared by red mud and water. The water used to formulate the red mud slurry may be industrial tap water or an aqueous solution produced in industrial production that has dissolved solutes that do not affect desulfurization.

The slurry collected in the first slurry collecting area 13 is led into the circulating pool 4 for recycling. The liquid in the circulating pool 4 still returns to the circulating pool 4 after being led into the upper spraying zone 11 and the middle spraying zone 12; but the calcium-based slurry and the red mud slurry which are newly introduced into the desulfurizing tower 1 enter the circulating tank 4 after being led into the lower spraying area 14 and enter the second slurry collecting area 15 to be separated from the circulating tank 4, and the flue gas is leached to be supplemented. In this way, the circulation tank 4 continuously discharges old slurry and introduces new slurry, which to a certain extent ensures the absorption capacity of the slurry in the circulation tank 4 for sulfides.

The slurry from the second slurry collection zone 15 is directed to a settling tank 5 for settling, after which it may be further processed.

The sixth pumping mechanism 66 may pump the slurry from the second slurry collection zone 15 to the lower spray zone 14 for spraying. The second slurry collection zone 15 has lower alkalinity, but can still carry out primary leaching on sulfur-containing flue gas, and the alkalinity is further reduced after the primary leaching, which is also beneficial to solid-liquid separation and the utilization of desulfurization byproducts.

According to the method, the sulfur-containing flue gas is leached in the same desulfurizing tower 1 by utilizing the calcium-based slurry and the red mud slurry simultaneously, and the calcium-based slurry and the red mud slurry are used as the circulating pool 4, so that additional equipment is not needed, the requirements on the site are low, the cost is low, the process steps are simple, and the method is easy to implement. Meanwhile, the purpose of dealkalizing the red mud is realized, and the recycling of the red mud is facilitated.

In some embodiments of the present application, the desulfurization system further comprises a solid-liquid separation system 7, the solid-liquid separation system 7 is communicated with the bottom of the sedimentation tank 5, and the solid-liquid separation system 7 is also communicated with the calcium-based slurry tank 2 and the red mud slurry tank 3.

The solid-liquid separation system 7 can separate out slurry with high solid content at the bottom of the sedimentation tank 5, and the main solutes in the slurry are low alkaline substances such as calcium sulfate, calcium sulfite, calcium silicate and the like. The solid-liquid separation system 7 is communicated with the calcium-based slurry pool 2 and the red mud slurry pool 3, and can send the separated aqueous solution to the calcium-based slurry pool 2 and the red mud slurry pool 3 for preparing the calcium-based slurry and the red mud slurry.

In some embodiments of the present application, the desulfurization system further comprises an evaporative crystallization system 8, the evaporative crystallization system 8 is in communication with the solid-liquid separation system 7, and the evaporative crystallization system 8 is also in communication with the calcium-based slurry tank 2 and the red mud slurry tank 3.

The solid-liquid separation system 7 can guide the separated aqueous solution into the evaporative crystallization system 8, the evaporative crystallization system 8 obtains crystals and sodium-removed water which take sodium sulfate as main components after the evaporative crystallization treatment, and then the sodium-removed water is sent to the calcium-based slurry pool 2 and the red mud slurry pool 3 for preparing calcium-based slurry and red mud slurry. A small amount of sodium sulfate does not affect sulfur absorption, but too much sodium sulfate causes deterioration in solubility and dispersibility of the calcium-based desulfurizing agent and red mud, and eventually decreases desulfurization efficiency. Therefore, when the concentration of sodium sulfate is low, the aqueous solution separated by the solid-liquid separation system 7 can be directly sent to the calcium-based slurry pool 2 and the red mud slurry pool 3; when the concentration of sodium sulfate is too high, the aqueous solution of the solid-liquid separation system 7 is treated by the evaporation and crystallization system 8 to form sodium-removed water, and then the sodium-removed water can be sent to the calcium-based slurry pool 2 and the red mud slurry pool 3.

In a second aspect, embodiments of the present application provide a desulfurization method, including the steps of:

providing a desulfurization system according to any one of the embodiments of the first aspect, introducing sulfur-containing flue gas from the flue gas inlet 16 into the desulfurization system;

introducing the calcium-based slurry in the calcium-based slurry tank 2 into the upper stage spray zone 11 through the first pumping mechanism 61;

introducing the red mud slurry in the red mud slurry pond 3 into the middle section spraying area 12 through the second pumping mechanism 62;

introducing the circulating wash liquid in the circulating tank 4 into the upper stage spray zone 11, the middle stage spray zone 12 and the lower stage spray zone 14 through the third pumping mechanism 63, the fourth pumping mechanism 64 and the fifth pumping mechanism 65, respectively;

the slurry in the second slurry collection zone 15 is directed to the sedimentation tank 5.

The upper spray zone 11 and the middle spray zone 12 are areas with higher pH value of leacheate, and the red mud slurry, the calcium-based slurry and the mixed slurry thereof are utilized to continuously react with the sulfur-containing flue gas after preliminary desulfurization, so that the red mud slurry and the calcium-based slurry are fully mixed in the desulfurization process, sodium ions are promoted to be transferred from the red mud solid phase to the desulfurization liquid phase, the alkalinity of the red mud is reduced, and near zero emission of sulfur dioxide in the flue gas is realized.

In some embodiments of the present application, the pH of the circulation tank 4 is controlled to be 5.5-6.5.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

feeding the slurry from the second slurry collection zone 15 to the lower shower zone 14;

the slurry in the second slurry collection zone 15 is directed to the sedimentation tank 5 until the pH is above 5.3 when the slurry pH is below 4.0 or the solids content is above 10%.

The lower spraying zone 14 is a low pH value slurry circulation desulfurization zone, the contact reaction is carried out by utilizing the raw flue gas containing high concentration sulfur dioxide and the low pH value slurry, the slurry circulates for many times under the low pH value condition, so that the preliminary desulfurization of sulfur dioxide is realized, the deep dealkalization of red mud is realized, byproducts such as calcium sulfate, calcium silicate and the like are generated, and meanwhile, sodium sulfate is enriched in the solution.

It should be noted that, the alkalinity of the slurry in the second slurry collecting area 15 may be increased by guiding the slurry in the second slurry collecting area 15 to the sedimentation tank 5, because the circulating washing liquid in the circulating tank 4 is guided into the lower spraying area 14 through the fifth pumping mechanism 65 and then is collected into the second slurry collecting area 15 after being sprayed, and the alkalinity of the circulating washing liquid in the circulating tank 4 is higher, so that the slurry in the second slurry collecting area 15 may be raised after being guided out to the sedimentation tank 5.

The feeding of the slurry from the second slurry collection zone 15 to the lower spray zone 14 may be performed by the sixth pumping mechanism 66.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

carrying out solid-liquid separation on the slurry in the sedimentation tank 5 to obtain clear liquid and desulfurization byproducts;

preparing the calcium-based slurry in the calcium-based slurry pond 2 by taking a calcium-based desulfurizing agent and the clear liquid as raw materials;

red mud and the clear liquid are used as raw materials to prepare the red mud slurry in the red mud liquid pool 3.

The solid-liquid separation may be performed by the solid-liquid separation system 7.

In some embodiments of the present application, when the sodium sulfate in the supernatant of the sedimentation tank 5 reaches a predetermined concentration, the desulfurization method further includes the steps of:

carrying out solid-liquid separation on the slurry in the sedimentation tank 5 to obtain clear liquid and desulfurization byproducts;

evaporating and concentrating the clear liquid to obtain sodium-removing water and crystalline salt;

preparing the calcium-based slurry in the calcium-based slurry pool 2 by taking a calcium-based desulfurizing agent and the sodium removing water as raw materials;

preparing the red mud slurry in the red mud slurry pool 3 by taking red mud and the sodium removing water as raw materials,

Wherein the predetermined concentration is 100-220g/L.

The evaporative concentration may be performed by the evaporative crystallisation system 8.

In some embodiments of the present application, the calcium-based slurry has a solids content of 4.2% to 14.5%; and/or the number of the groups of groups,

the liquid-solid ratio of the red mud slurry is 30:1-3:1, and the pH value is 7.3-9.8.

In some embodiments of the present application, the desulfurization method further comprises the steps of:

according to the mass of sulfur dioxide in the introduced flue gas, adding a desulfurization alkali-reducing accelerator into the circulating pool 4,

wherein the mass ratio of the desulfurization alkali-reducing accelerant to the sulfur dioxide is 0.05-0.1:1, the desulfurization alkali-reducing accelerant comprises ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon.

After the desulfurization accelerator is added into the red mud and the calcium-based desulfurizing agent for multiple times of cyclic desulfurization under the chemical environment condition of the circulating pool 4, the desulfurization efficiency is obviously improved, the dealkalization capability of the red mud is obviously enhanced, and the components such as potassium, magnesium, organic matters, activated carbon and the like contained in the accelerator further strengthen the functional effect of desulfurization byproducts as ecological restoration of the red mud storage yard, thereby being beneficial to realizing ecological restoration work of the red mud storage yard.

In a third aspect, embodiments of the present application provide an application of the desulfurization byproduct, where the desulfurization byproduct is the desulfurization byproduct in the second aspect, and the application of the desulfurization byproduct includes:

10-30 parts of red mud, 10-30 parts of desulfurization byproducts, 2-9 parts of organic biomass, 1-5 parts of farmyard manure, 2-7 parts of ash and 0.5-1 part of microbial fertilizer are mixed by weight and then paved on a red mud storage yard for ecological restoration.

It can be appreciated by those skilled in the art that the desulfurization system using red mud at present can continuously consume a large amount of fresh red mud, but a large amount of desulfurization byproducts are generated, and the desulfurization byproducts are difficult to utilize and cannot be absorbed by the market, and still face the problem of accumulation.

The desulfurization byproducts obtained by the method contain sodium alkali less than 0.1 percent and have the characteristics of looseness and porosity. After the desulfurization byproducts, the raw red mud, the carbonaceous matters, the farmyard manure, the ash and the microbial fertilizer are blended, the mixture is evenly spread on the red mud storage yard, so that the plant growth requirements are completely met, the soil is saved, the cultivated land resources are protected, the ecological restoration of the red mud storage yard is realized, and the utilization problems of small consumption of the desulfurization byproducts and high ecological restoration cost of the red mud storage yard are solved.

In some embodiments of the present application, the organic biomass comprises one of peanut hulls, walnut hulls, straw, sawdust, rice hulls, and corn cobs.

In some embodiments of the present application, the farmyard manure comprises one of chicken manure, duck manure, pig manure, cow manure.

The present application is further illustrated below in conjunction with specific embodiments. It should be understood that these examples are illustrative only of the present application and are not intended to limit the scope of the present application. The experimental procedures, which are not specified in the following examples, are generally determined according to national standards. If the corresponding national standard does not exist, the method is carried out according to the general international standard, the conventional condition or the condition recommended by the manufacturer.

Example 1

The present embodiment provides a desulfurization system including:

the desulfurization tower 1 comprises an upper spray zone 11, a middle spray zone 12, a first slurry collecting zone 13, a lower spray zone 14 and a second slurry collecting zone 15 from top to bottom in sequence, wherein the liquids in the upper spray zone 11 and the middle spray zone 12 are converged into the first slurry collecting zone 13, the liquid in the lower spray zone 14 is converged into the second slurry collecting zone 15, a flue gas inlet 16 is formed in the lower part of the desulfurization tower 1 below the lower spray zone 14, and a flue gas outlet 17 is formed in the top of the desulfurization tower 1;

a calcium-based slurry pool 2 which is communicated with the upper spraying zone 11 through a first pumping mechanism 61;

The red mud liquid pool 3 is communicated with the middle section spraying area 12 through a second pumping mechanism 62;

a circulation tank 4 is communicated with the first slurry collecting area 13, the circulation tank 4 is also communicated with the upper spraying area 11 through a third pumping mechanism 63, the circulation tank 4 is also communicated with the middle spraying area 12 through a fourth pumping mechanism 64, and the circulation tank 4 is also communicated with the lower spraying area 14 through a fifth pumping mechanism 65;

a sedimentation tank 5 which is communicated with the second slurry collecting zone 15, wherein the second slurry collecting zone 15 is also communicated with the lower-stage spraying zone 14 through a sixth pumping mechanism 66;

the solid-liquid separation system 7 is communicated with the bottom of the sedimentation tank 5, and the solid-liquid separation system 7 is also communicated with the calcium-based slurry tank 2 and the red mud slurry tank 3;

the evaporation crystallization system 8 is communicated with the solid-liquid separation system 7, and the evaporation crystallization system 8 is also communicated with the calcium-based slurry pool 2 and the red mud slurry pool 3.

Example 2

The present embodiment provides the desulfurization system of embodiment 1, and provides a desulfurization method based on the desulfurization system, including:

sulfur dioxide concentration of about 5500mg/m ³ And (3) introducing the flue gas into the desulfurization tower 1, preparing calcium-based slurry with the solid content of 10.5%, and conveying the calcium-based slurry to the upper spraying zone 11, wherein the calcium-based slurry is specifically calcium carbonate slurry. Preparing red mud slurry with the liquid-solid ratio of 9:1, conveying the red mud slurry to a middle-section spraying area 12, collecting the slurry in a first slurry collecting area 13, and conveying the slurry to a circulating tank 4 for circulatingAdding 2.3kg of desulfurization and alkali-reducing accelerant into the annular pool 4, and conveying the slurry in the circulating pool 4 to the upper spraying zone 11 and the middle spraying zone 12 by utilizing a third pumping mechanism 63 and a fourth pumping mechanism 64 for circulating desulfurization, wherein the desulfurization and alkali-reducing accelerant is formed by mixing ascorbic acid, glucose, potassium chloride, magnesium chloride and activated carbon in a mass ratio of 0.5:0.2:1:1:3; the slurry in the circulating pool 4 is conveyed to the lower spraying area 14 by a fifth pumping mechanism 65, is collected in the second slurry collecting area 15 after desulfurization in the lower spraying area 14, and the slurry in the bottom slurry pool is pumped into the lower spraying area 14 by a sixth pumping mechanism 66 for circulating desulfurization. The liquid-gas ratio of the desulfurizing tower 1 is kept at 6.5, and the pH value of the circulating pool 4 is kept at 6.5.

When the second slurry collection zone 15 is detected to have a pH of less than 4.5 or a solids content of greater than 12%, the slurry is fed to the sedimentation tank 5 while the circulation tank 4 is replenished with slurry to the second slurry collection zone 15 until the pH of the slurry therein reaches 5.3.

After the slurry in the sedimentation tank 5 is sedimentated, the slurry at the bottom of the sedimentation tank is conveyed to a solid-liquid separation system 7, the solid separated by the solid-liquid separation system 7 is used as a desulfurization byproduct, and the separated liquid is conveyed to a calcium-based slurry tank 2 and a red mud slurry tank 3 for preparing the calcium-based slurry and the red mud slurry.

When the concentration of sodium sulfate in supernatant liquid in the sedimentation tank 5 is detected to be more than 150g/L, liquid separated by the solid-liquid separation system 7 is conveyed to the evaporation crystallization system 8, salt is produced by the evaporation crystallization system 8, and sodium-removed water obtained after desalination is conveyed to the calcium-based slurry tank 2 and the red mud slurry tank 3 for preparing calcium-based slurry and red mud slurry.

The concentration of sulfur dioxide in the flue gas at the outlet of the final desulfurizing tower 1 is less than 1mg/m ³ Realizing near zero emission.

Example 3

The present embodiment provides the desulfurization system of embodiment 1, and provides a desulfurization method based on the desulfurization system, including:

the sulfur dioxide concentration is about 6200mg/m ³ And (3) introducing the flue gas into the desulfurization tower 1, preparing calcium-based slurry with the solid content of 8.0 percent, and conveying the calcium-based slurry to the upper spraying zone 11, wherein the calcium-based slurry is specifically calcium oxide slurry. PreparingThe red mud slurry with the liquid-solid ratio of 13:1 is conveyed to the middle-stage spraying area 12, the slurry is collected by the first slurry collecting area 13 and then conveyed to the circulating pool 4, 3.5kg of desulfurization and alkali-reduction promoter is added into the circulating pool 4, and the slurry in the circulating pool 4 is conveyed to the upper-stage spraying area 11 and the middle-stage spraying area 12 by utilizing the third pumping mechanism 63 and the fourth pumping mechanism 64 to carry out circulating desulfurization, wherein the desulfurization and alkali-reduction promoter is formed by mixing ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon in the mass ratio of 0.5:0.2:1:1:3; the slurry in the circulating pool 4 is conveyed to the lower spraying area 14 by a fifth pumping mechanism 65, is collected in the second slurry collecting area 15 after desulfurization in the lower spraying area 14, and the slurry in the bottom slurry pool is pumped into the lower spraying area 14 by a sixth pumping mechanism 66 for circulating desulfurization. The liquid-gas ratio of the desulfurizing tower 1 is kept at 5.0, and the pH value of the circulating pool 4 is kept at 5.7.

When the second slurry collection zone 15 is detected to have a pH of less than 4.5 or a solids content of greater than 12%, the slurry is fed to the sedimentation tank 5 while the circulation tank 4 is replenished with slurry to the second slurry collection zone 15 until the pH of the slurry therein reaches 5.3.

After the slurry in the sedimentation tank 5 is sedimentated, the slurry at the bottom of the sedimentation tank is conveyed to a solid-liquid separation system 7, the solid separated by the solid-liquid separation system 7 is used as a desulfurization byproduct, and the separated liquid is conveyed to a calcium-based slurry tank 2 and a red mud slurry tank 3 for preparing the calcium-based slurry and the red mud slurry.

When the concentration of sodium sulfate in supernatant liquid in the sedimentation tank 5 is detected to be more than 150g/L, liquid separated by the solid-liquid separation system 7 is conveyed to the evaporation crystallization system 8, salt is produced by the evaporation crystallization system 8, and sodium-removed water obtained after desalination is conveyed to the calcium-based slurry tank 2 and the red mud slurry tank 3 for preparing calcium-based slurry and red mud slurry.

The concentration of sulfur dioxide in the flue gas at the outlet of the final desulfurizing tower 1 is less than 1mg/m ³ Realizing near zero emission.

Example 4

The present embodiment provides the desulfurization system of embodiment 1, and provides a desulfurization method based on the desulfurization system, including:

the sulfur dioxide concentration was about 3700mg/m ³ Is introduced into the desulfurization A tower 1 prepares a calcium-based slurry with a solid content of 5.8% and delivers the slurry to an upper spray zone 11, wherein the calcium-based slurry is specifically a calcium oxide slurry. Preparing red mud slurry with a liquid-solid ratio of 17:1, conveying the red mud slurry to a middle-stage spraying area 12, collecting the slurry by a first slurry collecting area 13, conveying the slurry to a circulating pond 4, adding 1.5kg of desulfurization and alkali-reduction promoter into the circulating pond 4, and conveying the slurry in the circulating pond 4 to an upper-stage spraying area 11 and the middle-stage spraying area 12 by using a third pumping mechanism 63 and a fourth pumping mechanism 64 for circulating desulfurization, wherein the desulfurization and alkali-reduction promoter is formed by mixing ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon in a mass ratio of 0.5:0.2:1:1:3; the slurry in the circulating pool 4 is conveyed to the lower spraying area 14 by a fifth pumping mechanism 65, is collected in the second slurry collecting area 15 after desulfurization in the lower spraying area 14, and the slurry in the bottom slurry pool is pumped into the lower spraying area 14 by a sixth pumping mechanism 66 for circulating desulfurization. The liquid-gas ratio of the desulfurizing tower 1 is kept at 5.0, and the pH value of the circulating pool 4 is kept at 5.8.

When the second slurry collection zone 15 is detected to have a pH of less than 4.5 or a solids content of greater than 12%, the slurry is fed to the sedimentation tank 5 while the circulation tank 4 is replenished with slurry to the second slurry collection zone 15 until the pH of the slurry therein reaches 5.3.

After the slurry in the sedimentation tank 5 is sedimentated, the slurry at the bottom of the sedimentation tank is conveyed to a solid-liquid separation system 7, the solid separated by the solid-liquid separation system 7 is used as a desulfurization byproduct, and the separated liquid is conveyed to a calcium-based slurry tank 2 and a red mud slurry tank 3 for preparing the calcium-based slurry and the red mud slurry.

When the concentration of sodium sulfate in supernatant liquid in the sedimentation tank 5 is detected to be more than 150g/L, liquid separated by the solid-liquid separation system 7 is conveyed to the evaporation crystallization system 8, salt is produced by the evaporation crystallization system 8, and sodium-removed water obtained after desalination is conveyed to the calcium-based slurry tank 2 and the red mud slurry tank 3 for preparing calcium-based slurry and red mud slurry.

The concentration of sulfur dioxide in the flue gas at the outlet of the final desulfurizing tower 1 is less than 1mg/m ³ Realizing near zero emission.

Example 5

The present embodiment provides the desulfurization system of embodiment 1, and provides a desulfurization method based on the desulfurization system, including:

the sulfur dioxide concentration is about 1600mg/m ³ And (3) introducing the flue gas into the desulfurization tower 1, preparing calcium-based slurry with the solid content of 5.5%, and conveying the calcium-based slurry to the upper spraying zone 11, wherein the calcium-based slurry is specifically calcium oxide slurry. Preparing red mud slurry with a liquid-solid ratio of 25:1, conveying the red mud slurry to a middle-stage spraying area 12, collecting the slurry by a first slurry collecting area 13, conveying the slurry to a circulating pond 4, adding 1.0kg of desulfurization and alkali-reduction promoter into the circulating pond 4, and conveying the slurry in the circulating pond 4 to an upper-stage spraying area 11 and the middle-stage spraying area 12 by using a third pumping mechanism 63 and a fourth pumping mechanism 64 for circulating desulfurization, wherein the desulfurization and alkali-reduction promoter is formed by mixing ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon in a mass ratio of 0.5:0.2:1:1:3; the slurry in the circulating pool 4 is conveyed to the lower spraying area 14 by a fifth pumping mechanism 65, is collected in the second slurry collecting area 15 after desulfurization in the lower spraying area 14, and the slurry in the bottom slurry pool is pumped into the lower spraying area 14 by a sixth pumping mechanism 66 for circulating desulfurization. The liquid-gas ratio of the desulfurizing tower 1 is kept at 4.5, and the pH value of the circulating pool 4 is kept at 5.5.

When the second slurry collection zone 15 is detected to have a pH of less than 4.5 or a solids content of greater than 12%, the slurry is fed to the sedimentation tank 5 while the circulation tank 4 is replenished with slurry to the second slurry collection zone 15 until the pH of the slurry therein reaches 5.3.

After the slurry in the sedimentation tank 5 is sedimentated, the slurry at the bottom of the sedimentation tank is conveyed to a solid-liquid separation system 7, the solid separated by the solid-liquid separation system 7 is used as a desulfurization byproduct, and the separated liquid is conveyed to a calcium-based slurry tank 2 and a red mud slurry tank 3 for preparing the calcium-based slurry and the red mud slurry.

When the concentration of sodium sulfate in supernatant liquid in the sedimentation tank 5 is detected to be more than 150g/L, liquid separated by the solid-liquid separation system 7 is conveyed to the evaporation crystallization system 8, salt is produced by the evaporation crystallization system 8, and sodium-removed water obtained after desalination is conveyed to the calcium-based slurry tank 2 and the red mud slurry tank 3 for preparing calcium-based slurry and red mud slurry.

The concentration of sulfur dioxide in the flue gas at the outlet of the final desulfurizing tower 1 is less than 1mg/m ³ Realizing near zero emission.

Example 6

The present embodiment provides the desulfurization system of embodiment 1, and provides a desulfurization method based on the desulfurization system, including:

the sulfur dioxide concentration is about 7200mg/m ³ And (3) introducing the flue gas into the desulfurization tower 1, preparing calcium-based slurry with the solid content of 10.0%, and conveying the calcium-based slurry to the upper spraying zone 11, wherein the calcium-based slurry is specifically calcium hydroxide slurry. Preparing red mud slurry with a liquid-solid ratio of 5:1, conveying the red mud slurry to a middle-stage spraying area 12, collecting the slurry by a first slurry collecting area 13, conveying the slurry to a circulating pond 4, adding 5.0kg of desulfurization and alkali-reduction promoter into the circulating pond 4, and conveying the slurry in the circulating pond 4 to an upper-stage spraying area 11 and the middle-stage spraying area 12 by using a third pumping mechanism 63 and a fourth pumping mechanism 64 for circulating desulfurization, wherein the desulfurization and alkali-reduction promoter is formed by mixing ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon in a mass ratio of 0.5:0.2:1:1:3; the slurry in the circulating pool 4 is conveyed to the lower spraying area 14 by a fifth pumping mechanism 65, is collected in the second slurry collecting area 15 after desulfurization in the lower spraying area 14, and the slurry in the bottom slurry pool is pumped into the lower spraying area 14 by a sixth pumping mechanism 66 for circulating desulfurization. The liquid-gas ratio of the desulfurizing tower 1 is kept at 6.0, and the pH value of the circulating pool 4 is kept at 6.5.

When the second slurry collection zone 15 is detected to have a pH of less than 4.5 or a solids content of greater than 12%, the slurry is fed to the sedimentation tank 5 while the circulation tank 4 is replenished with slurry to the second slurry collection zone 15 until the pH of the slurry therein reaches 5.3.

After the slurry in the sedimentation tank 5 is sedimentated, the slurry at the bottom of the sedimentation tank is conveyed to a solid-liquid separation system 7, the solid separated by the solid-liquid separation system 7 is used as a desulfurization byproduct, and the separated liquid is conveyed to a calcium-based slurry tank 2 and a red mud slurry tank 3 for preparing the calcium-based slurry and the red mud slurry.

When the concentration of sodium sulfate in supernatant liquid in the sedimentation tank 5 is detected to be more than 150g/L, liquid separated by the solid-liquid separation system 7 is conveyed to the evaporation crystallization system 8, salt is produced by the evaporation crystallization system 8, and sodium-removed water obtained after desalination is conveyed to the calcium-based slurry tank 2 and the red mud slurry tank 3 for preparing calcium-based slurry and red mud slurry.

Final desulfurizationThe concentration of sulfur dioxide in the flue gas at the outlet of the tower 1 is less than 1mg/m ³ Realizing near zero emission.

Example 7

The desulfurization byproducts obtained in examples 2 to 5 were mixed at the same mass to obtain a mixed desulfurization byproduct.

15 parts of red mud, 15 parts of mixed desulfurization byproducts, 7 parts of organic biomass, 3 parts of farmyard manure, 5 parts of ash slag and 1 part of microbial fertilizer are mixed and paved on a red mud yard for ecological restoration, after planting saline-alkali-resistant and drought-resistant plant grass seeds, the germination rate reaches about 70% after 10 days, the germination rate reaches more than 78% after 15 days, the vegetation coverage rate reaches more than 88% after 100 days, and the natural re-greening area of vegetation exceeds more than 75% after one year.

Comparative example 1

This comparative example differs from example 6 only in that: no desulfurization and alkali reduction promoter is added.

The result shows that the concentration of sulfur dioxide in the flue gas at the outlet of the desulfurizing tower is 10-35 mg/m ³ And the desulfurization effect shows a tendency to decrease.

Comparative example 2

The desulfurization by-product obtained in comparative example 1 was provided.

15 parts of red mud, 15 parts of desulfurization byproducts obtained in comparative example 1, 7 parts of organic biomass, 3 parts of farmyard manure, 5 parts of ash residues and 1 part of microbial fertilizer are mixed and laid on a red mud storage yard for ecological restoration, and after planting saline-alkali-resistant and drought-resistant plant seeds, the germination rate reaches about 70% after 10 days, the germination rate reaches more than 75% after 15 days, the vegetation coverage rate reaches about 80% after 100 days, the natural re-greening area of vegetation is about 70% after one year, and the vegetation has the phenomena of plant diseases and insect pests, yellow leaves and wilting more.

Comparative example 3

This comparative example differs from example 6 only in that: the calcium-based slurry with the solid content of 10.0% is replaced by the red mud slurry with the solid content of 10.0%.

The result shows that the sulfur dioxide concentration of the flue gas at the outlet of the desulfurizing tower is 85mg/m ³ The desulfurization effect is obviously poor.

Comparative example 4

This comparative example differs from example 6 only in that: when the concentration of sodium sulfate in the supernatant in the sedimentation tank 5 exceeds 150g/L, the evaporative crystallization system 8 is not started.

The result shows that as the concentration of sodium sulfate in the supernatant liquid is gradually enriched and increased, the desulfurization efficiency is gradually reduced, and when the concentration of sodium sulfate exceeds 1000g/L, the concentration of sulfur dioxide in flue gas at the outlet of the desulfurization tower exceeds 100mg/m ³ The desulfurization effect is obviously poor.

Various embodiments of the present application may exist in a range format; it should be understood that the description in a range format is merely for convenience and brevity and should not be interpreted as a rigid limitation on the scope of the application. It is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.

In this application, unless otherwise indicated, terms of orientation such as "upper" and "lower" are used specifically to refer to the orientation of the drawing in the figures. In addition, in the description of the present application, the terms "include", "comprise", "comprising" and the like mean "including but not limited to". Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element. Relational terms such as "first" and "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Herein, "and/or" describing an association relationship of an association object means that there may be three relationships, for example, a and/or B, may mean: a alone, a and B together, and B alone. For the association relation of more than three association objects described by the "and/or", it means that any one of the three association objects may exist alone or any at least two of the three association objects exist simultaneously, for example, for a, and/or B, and/or C, any one of the A, B, C items may exist alone or any two of the A, B, C items exist simultaneously or three of the three items exist simultaneously. Herein, "at least one" means one or more, and "a plurality" means two or more. "at least one", "at least one" or the like refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.

The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A desulfurization system, characterized in that the desulfurization system comprises:

the desulfurization tower comprises an upper section spraying area, a middle section spraying area, a first slurry collecting area, a lower section spraying area and a second slurry collecting area from top to bottom in sequence, wherein the liquid in the upper section spraying area and the liquid in the middle section spraying area are converged into the first slurry collecting area, the liquid in the lower section spraying area is converged into the second slurry collecting area, a flue gas inlet is arranged below the lower section spraying area at the lower part of the desulfurization tower, and a flue gas outlet is arranged at the top of the desulfurization tower;

the calcium-based slurry pool is communicated with the upper spray zone through a first pumping mechanism;

The red mud liquid pool is communicated with the middle section spraying area through a second pumping mechanism;

the circulating pool is communicated with the first slurry collecting area, is also communicated with the upper spraying area through a third pumping mechanism, is also communicated with the middle spraying area through a fourth pumping mechanism, and is also communicated with the lower spraying area through a fifth pumping mechanism;

the sedimentation tank is communicated with the second slurry collecting area, and the second slurry collecting area is also communicated with the lower-stage spraying area through a sixth pumping mechanism.

2. The desulfurization system of claim 1, further comprising a solid-liquid separation system in communication with the bottom of the sedimentation tank, the solid-liquid separation system further in communication with the calcium-based slurry tank and the red mud slurry tank.

3. The desulfurization system of claim 3, further comprising an evaporative crystallization system in communication with the solid-liquid separation system, the evaporative crystallization system further in communication with the calcium-based slurry pond and the red mud slurry pond.

4. A desulfurization method, characterized in that the desulfurization method comprises the steps of:

providing a desulfurization system as claimed in any one of claims 1-4, introducing sulfur-containing flue gas from said flue gas inlet into said desulfurization system;

introducing the calcium-based slurry in the calcium-based slurry tank into the upper spray zone through the first pumping mechanism;

the red mud slurry in the red mud slurry pond is guided into the middle section spraying area through the second pumping mechanism;

introducing circulating washing liquid in the circulating pool into the upper-stage spraying area, the middle-stage spraying area and the lower-stage spraying area through the third pumping mechanism, the fourth pumping mechanism and the fifth pumping mechanism respectively;

introducing the slurry in the second slurry collection zone into the settling tank.

5. The desulfurization method according to claim 4, characterized by further comprising the steps of:

feeding the slurry from the second slurry collection zone into the lower spray zone;

when the pH of the slurry in the second slurry collection zone is below 4.0 or the solid content is greater than 10%, the slurry is introduced into the sedimentation tank until the pH is above 5.3.

6. The desulfurization method according to claim 5, characterized by further comprising the steps of:

Carrying out solid-liquid separation on the slurry in the sedimentation tank to obtain clear liquid and desulfurization byproducts;

preparing the calcium-based slurry in the calcium-based slurry pond by taking a calcium-based desulfurizing agent and the clear liquid as raw materials;

red mud and the clear liquid are used as raw materials to prepare the red mud slurry in the red mud slurry pond.

7. The desulfurization method according to claim 5, characterized in that when sodium sulfate in the supernatant of the sedimentation tank reaches a predetermined concentration, the desulfurization method further comprises the steps of:

carrying out solid-liquid separation on the slurry in the sedimentation tank to obtain clear liquid and desulfurization byproducts;

evaporating and concentrating the clear liquid to obtain sodium-removing water and crystalline salt;

preparing the calcium-based slurry in the calcium-based slurry pool by taking a calcium-based desulfurizing agent and the sodium removing water as raw materials;

red mud and the sodium removing water are used as raw materials to prepare the red mud slurry in the red mud liquid pool,

wherein the predetermined concentration is 100-220g/L.

8. The desulfurization method according to claim 4, wherein the calcium-based slurry has a solid content of 4.2% to 14.5%; and/or the number of the groups of groups,

the liquid-solid ratio of the red mud slurry is 30:1-3:1, and the pH value is 7.3-9.8.

9. The desulfurization method according to claim 4, characterized by further comprising the steps of:

According to the mass of sulfur dioxide in the imported flue gas, adding a desulfurization alkali-reducing accelerator into the circulating pool,

wherein the mass ratio of the desulfurization alkali-reducing accelerant to the sulfur dioxide is 0.05-0.1:1, the desulfurization alkali-reducing accelerant comprises ascorbic acid, glucose, potassium chloride, magnesium chloride and active carbon.

10. Use of a desulfurization by-product according to any one of claims 4-9, comprising:

10-30 parts of red mud, 10-30 parts of desulfurization byproducts, 2-9 parts of organic biomass, 1-5 parts of farmyard manure, 2-7 parts of ash and 0.5-1 part of microbial fertilizer are mixed by weight and then paved on a red mud storage yard for ecological restoration.

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