阅读说明：本技术 一种脱硫脱硝除尘一体化工艺 (Desulfurization, denitrification and dust removal integrated process ) 是由 徐继红 陶俊 于 2021-06-24 设计创作，主要内容包括：一种脱硫脱硝除尘一体化工艺,一般工艺过程：烟气由引风机送入脱硫脱硝除尘一体化塔,烟气由下往上,喷淋液自上而下,在气液相穿越电催化反应层时,以选择电活性物质作为催化反应介质,在电场作用下在电活性物质表面区域发生电催化反应,以吸收循环液中氨或尿素为还原剂使NOx生成N2,同时发生脱硫作用,后烟气经穿透液膜洗涤层,达成除尘作用,后净化烟气送烟囱达标排放；本发明的有益效果是：(1)脱硫脱硝除尘相互协同,高效低成本地解决了烟气处理难题；(2)变高消耗高污染过程为有产品价值的生产过程；(3)脱硝不受温度限制；(4)解决湿法脱硫雾沫夹带和可溶性盐带出问题以及氨逃逸问题；(5)占地面积小,投资成本低。(A desulfurization, denitrification and dust removal integrated process comprises the following general process steps: the flue gas is sent into a desulfurization, denitrification and dedusting integrated tower by a draught fan, the flue gas is from bottom to top, the spraying liquid is from top to bottom, when a gas-liquid phase passes through an electro-catalytic reaction layer, an electro-catalytic reaction is carried out on the surface area of the electro-active substance under the action of an electric field by taking the electro-active substance as a catalytic reaction medium, NOx is generated into N2 by taking ammonia or urea in absorption circulating liquid as a reducing agent, the desulfurization effect is simultaneously carried out, the flue gas passes through a liquid film washing layer to achieve the dedusting effect, and the purified flue gas is sent to a chimney to reach the standard and is discharged; the invention has the beneficial effects that: (1) the desulfurization, denitrification and dust removal are mutually cooperated, so that the problem of flue gas treatment is solved with high efficiency and low cost; (2) the process of high consumption and high pollution is a production process with product value; (3) denitration is not limited by temperature; (4) the problems of entrainment of wet desulphurization mist, entrainment of soluble salt and ammonia escape are solved; (5) the occupied area is small, and the investment cost is low.)

1. A desulfurization, denitrification and dust removal integrated process is characterized in that a main device is a desulfurization, denitrification and dust removal integrated tower which is generally used by a single tower, multiple layers of spraying are arranged in the tower, 4 layers of absorbing spraying are conventionally arranged, 1 layer of washing spraying is conventionally arranged, and a rotational flow plate layer, a desulfurization absorbing layer, an electro-catalytic reaction layer (2 layers are conventionally arranged) and a penetrating liquid film layer are arranged from bottom to top; the single electrocatalytic reaction layer consists of a bracket, a flue gas channel, an electrode and an electroactive filler;

the general process comprises the following steps: the flue gas is sent into the desulfurization denitration dust removal integration tower by the draught fan, sets up the dual cycle, and from bottom to top in 1 st circulation flue gas, 3 layers spray absorption liquid top-down, and the gaseous phase obtains mixing when passing through the whirl sheet layer, and the bottom sprays the layer and obtains moistening, at desulfurization absorption layer SO₂Most of the absorbed nitrogen is absorbed, when the gas-liquid phase passes through the electro-catalytic reaction layer, an electro-active substance is selected as a catalytic reaction medium, an electro-catalytic reaction is carried out on the surface of the electro-active substance under the action of an electric field, and the absorption of ammonia or urea in the circulating liquid is taken as a reducing agent to enable NOx to generate N₂(ii) a In the 2 nd circulation, the purified flue gas is sent to a chimney for standard discharge after being washed by a liquid permeable membrane;

the electrocatalysis reaction is that direct current is introduced, the voltage is 1-60V, and the following selective catalysis reaction is carried out:

2CO(NH₂)₂+6NO=5N₂+2CO₂+4H₂O

or 4NH₃+6NO=5N₂+6H₂0

The desulfurization method comprises the following steps: a process for desulfurizing and co-producing gypsum whiskers by a limestone method, which has the following patent numbers: ZL 201210268591.1; the process adopts ammonium sulfate as a process absorbent, the absorption process is changed, the crystal form of the desulfurized gypsum is changed, the desulfurization efficiency benefit is greatly improved, a series of problems of desulfurization by the traditional lime gypsum method are overcome, and the desulfurization process is changed into a production process of whisker products;

the dust removal method relates to: a penetrating liquid film absorption device, patent no: ZL 201710176797.4; the device is provided with a conical wire mesh surface, liquid forms a liquid film along the conical wire mesh surface, gas permeates the liquid film on the conical wire mesh surface under the internal-external pressure difference of the conical surface, and the absorbed components and dust in the flue gas are absorbed by the liquid film.

Technical Field

The invention belongs to the field of boiler tail gas treatment. The invention relates to a desulfurization, denitrification and dust removal integrated process for removing SO in flue gas₂NOx and dust, more particularlyThe desulfurization, denitrification and dust removal are completed in a main absorption tower device, the occupied area is small, the equipment investment is small, the effect is good, the integrated system with complete functions is provided, and the flue gas after treatment reaches the ultra-clean emission standard.

Background

The most widely used desulfurization technique at present is a wet lime-gypsum method, which has the following problems: 1) the desulfurization pipeline is easy to block; 2) the utilization rate of the raw materials of the absorbent is low; 3) calcium sulfite is difficult to oxidize, and an oxidation fan has large power consumption; 4) the by-product calcium sulfate is viscous, difficult to filter and high in water content; 5) the quality of the calcium sulfate byproduct is low;

at present, the most widely applied denitration technology at home and abroad is medium-high temperature SCR denitration, and the application characteristic of the method is that a proper temperature zone is needed, but in sintering flue gas such as brick and tile industry, lime industry and steel industry, the method has no temperature zone needed by the medium-high temperature SCR denitration due to the characteristics of production technology, and has three problems in the treatment of the flue gas in the industries: 1) heating is needed, and huge energy is consumed; 2) heat exchange and other facilities are required to be arranged, so that the flow is prolonged, and the investment is enlarged; 3) the catalyst has large consumption and large loss.

The 'wet electricity' process is generally adopted in the transformation of ultra-low emission of dust removal, and three problems also exist: 1) the wet electricity effect is greatly influenced by a desulfurization system, and the demisting function of the wet electricity effect is gradually reduced; 2) the wet electric dust removal is additionally arranged, so that the investment and the operation cost are high; 3) wet electricity requires a high-voltage electric field, and the risk of combustion and explosion is high.

Disclosure of Invention

Aiming at the defects of various desulfurization, denitrification and dust removal processes, the application provides a desulfurization, denitrification and dust removal integrated process, which achieves the aims of desulfurization, denitrification and dust removal and achieves the effects of low system investment, low operation cost and stable and reliable operation.

A desulfurization, denitrification and dust removal integrated process is mainly characterized in that a desulfurization, denitrification and dust removal integrated tower is adopted as a main device, desulfurization relates to a limestone desulfurization and gypsum whisker co-production process, denitrification relates to an electrocatalytic denitrification method, and dust removal relates to a liquid film penetrating device; the general process comprises the following steps: the flue gas is sent into the integrated tower for desulfurization, denitrification and dust removal by a draught fan, and double circulation is arrangedIn the 1 st cycle, the flue gas flows from bottom to top, the spray liquid flows from top to bottom, when the gas-liquid phase passes through the electro-catalytic reaction layer, an electro-active substance is selected as a catalytic reaction medium, an electro-catalytic reaction is carried out on the surface area of the electro-active substance under the action of an electric field, and the absorption of ammonia or urea in the circulating liquid is taken as a reducing agent to enable NOx to generate N₂Simultaneously, the desulfurization effect is generated, the flue gas passes through the liquid film washing layer in the 2 nd cycle to achieve the dust removal effect, and then the purified flue gas is sent to a chimney to reach the standard and is discharged;

the desulfurization, denitrification and dust removal integrated tower is generally used in a single tower, wherein multiple layers of spraying are arranged in the tower, 4 layers of absorption spraying and 1 layer of washing spraying are conventionally arranged, and a rotational flow plate layer, a desulfurization absorption layer, an electrocatalytic reaction layer (2 layers are conventionally arranged) and a penetrating liquid film layer are arranged from bottom to top;

the desulfurization method involves: a process for desulfurizing and co-producing gypsum whiskers by a limestone method, which has the following patent numbers: ZL 201210268591.1; the process adopts ammonium sulfate as a process absorbent, the absorption process is changed, the crystal form of the desulfurized gypsum is changed, the desulfurization efficiency benefit is greatly improved, a series of problems of desulfurization by the traditional lime gypsum method are overcome, and the desulfurization process is changed into a production process of whisker products;

it is characterized in that:

1) homogeneous absorption, reduced power of the absorption circulating pump and energy conservation;

2) homogeneous absorption, the desulfurization pipeline can not be blocked;

3) the utilization rate of the raw materials of the absorbent is high, and the quality of the desulfurized slag is good;

4) the generated gypsum whisker is easy to filter, the water content of the desulfurized gypsum is low, the desulfurized gypsum is easy to dry, and the value of the byproduct is high.

The denitration relates to an electrocatalytic denitration method, wherein a single electrocatalytic reaction layer consists of a bracket, a flue gas channel, an electrode and an electroactive filler;

the electrocatalysis reaction is that direct current is introduced, the voltage is 1-60V, and the following selective catalysis reaction is carried out:

2CO(NH₂)₂+6NO=5N₂+2CO₂+4H₂O

or 4NH₃+6NO=5N₂+6H₂0。

It is characterized in that:

(1) the main device is an electrocatalysis reaction tower, and multiple layers of spraying are arranged in the electrocatalysis reaction tower, so that the electrocatalysis reaction tower is flexible in arrangement and strong in adaptability;

(2) the single electrocatalytic reaction layer consists of a bracket, a flue gas channel, an electrode and an electroactive filler; the single reactor has large smoke treatment amount, and the resistance of the electroactive packing layer is small;

(3) the sulfur-containing flue gas has a promoting effect on the wet electrocatalysis denitration process, and has no adverse effect;

(4) the process is simple, the investment cost is low, the installation is convenient and fast, the operation is easy, and the adaptability is strong.

The dust removal method involves: a penetrating liquid film absorption device, patent no: ZL 201710176797.4; the device is provided with a conical wire mesh surface, liquid forms a liquid film along the conical wire mesh surface, gas permeates the liquid film on the conical wire mesh surface under the internal and external pressure difference of the conical surface, and the absorbed components and dust in the flue gas are absorbed by the liquid film;

it solves the absorption and dust removal defogging problem of big gas capacity, and its characteristics are:

1) the gas-liquid contact is sufficient, the absorption efficiency is high, and the dust removal and demisting effects are good;

2) the conical wire mesh surface is a main absorption area, the liquid layer is thin, the gas resistance is small, the area of the liquid film is large, and the treatment gas amount is large;

3) the absorption and dust removal are integrated, the equipment structure is simple, the production and the installation are simple and convenient, the investment cost of the flue gas purification is low, and the operation and maintenance cost is low.

The invention is embodied in the following points:

(1) the integrated process for desulfurization, denitrification and dust removal is an integral technical system, and the desulfurization, denitrification and dust removal are mutually cooperated, so that the problem of flue gas treatment is solved with high efficiency and low cost;

(2) the desulfurization adopts a limestone desulfurization and gypsum whisker co-production process, overcomes the defect of lime-gypsum desulfurization, and takes a high-consumption and high-pollution process as a production process with product value;

(3) the denitration is wet electrocatalysis, normal-temperature denitration is not limited by temperature, and is generally used in a single tower, and multiple electrocatalysis layers are arranged in the electrocatalysis reaction tower, so that the denitration device is flexible in arrangement and strong in adaptability;

(4) the dust removal adopts a penetrating liquid film absorption device, solves the problems of absorption of large smoke volume, dust removal and demisting, and solves the problems of entrainment of wet desulphurization mist, entrainment of soluble salt and ammonia escape;

(5) small occupied area, low investment cost, easy operation and strong adaptability.

The specific implementation process of the invention is as follows:

a desulfurization, denitrification and dust removal integrated process is characterized in that a main device is a desulfurization, denitrification and dust removal integrated tower which is generally used by a single tower, multiple layers of spraying are arranged in the tower, 4 layers of absorbing spraying are conventionally arranged, 1 layer of washing spraying is conventionally arranged, and a rotational flow plate layer, a desulfurization absorbing layer, an electro-catalytic reaction layer (2 layers are conventionally arranged) and a penetrating liquid film layer are arranged from bottom to top; the single electrocatalytic reaction layer consists of a bracket, a flue gas channel, an electrode and an electroactive filler;

the general process comprises the following steps: the flue gas is sent into the desulfurization denitration dust removal integration tower by the draught fan, sets up the dual cycle, and from bottom to top in 1 st circulation flue gas, 3 layers spray absorption liquid top-down, and the gaseous phase obtains mixing when passing through the whirl sheet layer, and the bottom sprays the layer and obtains moistening, at desulfurization absorption layer SO₂Most of the absorbed nitrogen is absorbed, when the gas-liquid phase passes through the electro-catalytic reaction layer, an electro-active substance is selected as a catalytic reaction medium, an electro-catalytic reaction is carried out on the surface of the electro-active substance under the action of an electric field, and the absorption of ammonia or urea in the circulating liquid is taken as a reducing agent to enable NOx to generate N₂(ii) a In the 2 nd circulation, the purified flue gas is sent to a chimney for standard discharge after being washed by a liquid permeable membrane;

the electrocatalysis reaction is that direct current is introduced, and the voltage is 1-60V.

Drawings

FIG. 1 is a schematic process flow diagram of inventive example 1;

FIG. 2 is a schematic process flow diagram of inventive example 2;

FIG. 3 is a schematic process flow diagram of inventive example 3.

Detailed Description

Example 1

Example 1 is an example of an integrated process for desulfurization, denitrification and dedusting of low sulfur flue gas.

In fig. 1, a desulfurization, denitrification and dust removal integrated tower 1, a cyclone plate 2, an electro-catalytic layer 3, a penetrating liquid film layer 4, a demisting layer 5, a chimney 6, a washing and spraying layer 7, an absorption and spraying layer 8, an absorption and circulation pump 9, a washing and circulation pump 10, a filter pump 11 and a filter 12 are shown; flue gas A, purified flue gas B, ammonia water C, washing process water D and solid residues E.

The desulfurization, denitrification and dust removal integrated tower 1 is provided with double circulation, and is provided with a cyclone plate 2, 3 electro-catalytic layers 3, a penetrating liquid film layer 4 and a demisting layer 5 from bottom to top, and 4 absorption spraying layers 8 and 1 washing spraying layer 7; the electrocatalytic reaction layer consists of a bracket, an electrode and an electroactive filler, and the electrocatalytic layer is connected with an external direct-current power supply; the bottom of the integrated tower 1 is provided with a slurry area a, a reflux area b and a clear water area c;

the process comprises the following steps: the flue gas A enters the middle part of a desulfurization, denitrification and dust removal integrated tower 1 and is in countercurrent contact with absorption liquid sprayed from the upper part, the absorption liquid containing ammonia in the tower flows through an electrocatalytic layer 3 in the tower, and normal-temperature catalytic reaction is carried out on the surface area of an electroactive substance to enable NOx to generate N₂Meanwhile, sulfur dioxide is absorbed, absorption spray liquid falls into a tower bottom slurry pool a, and the 1 st circulation is realized in a backflow pool by an absorption circulating pump 9; the flue gas after desulfurization and denitrification enters the upper space of the integrated tower 1 through gas holes on the separation layer, the gas phase is washed away from carried soluble salts through the liquid penetration film layer 4, and then is discharged through a demister through a chimney on the top of the tower to reach the standard; spraying liquid penetrating through the liquid film layer 4 at the upper part of the integrated tower 1 is sprayed by the washing spraying layer 7, the spraying liquid falls into the bottom of the separation layer, then reflows to a clean water tank at the bottom of the separation layer through a pipeline, and then realizes the 2 nd circulation through the washing circulating pump 10; and a filtering pump 11 is additionally arranged in a slurry tank at the bottom of the integrated tower, slurry is pumped to a filtering machine 12, filtrate flows back to a backflow tank c, and solid residues E are mainly ammonium sulfate crystallization and dust mixture.

The electrolysis takes graphite as an electrode, and direct current is introduced, and the voltage is 20V.

The implementation effect is as follows: the desulfurization rate is more than or equal to 90 percent, the denitration rate is more than or equal to 90 percent, and the dust removal rate is more than or equal to 90 percent.

Example 2

Embodiment 2 is an example of a desulfurization, denitrification and dedusting integrated process with integrated tower and tank.

In FIG. 2, a desulfurization, denitrification and dust removal integrated tower 1, a chimney 2, a slurry tank 3, a gypsum whisker preparation tank 4, a clean water tank 5, an absorption circulating pump 6, a washing circulating pump 7, an automatic lime dosing device 8, a filter pump 9 and a filter 10 are arranged; flue gas A, purified flue gas B, lime C, washing process water D, ammonia water E and gypsum whisker F.

The desulfurization, denitrification and dust removal integrated tower 1 is provided with a dual cycle and a connected chimney 2, and the connected water tank is divided into a slurry tank 3, a gypsum whisker preparation tank 4 and a clean water tank 5;

the process comprises the following steps: the flue gas A enters the bottom of a desulfurization, denitrification and dust removal integrated tower 1 and is in countercurrent contact with absorption liquid sprayed from the upper part, the absorption liquid containing ammonia in the tower flows through an electro-catalytic layer in the tower, and normal-temperature catalytic reaction occurs in the surface area of an electro-active substance to enable NOx to generate N₂Meanwhile, sulfur dioxide is absorbed, absorption spray liquid falls into a slurry pool 3 of a connected water pool of the integrated tower 1, a chemical agent ammonia water E is supplemented, and the 1 st cycle is realized by an absorption circulating pump 6; the flue gas after desulfurization and denitrification enters the upper space of the integrated tower 1 through gas holes on the separation layer, the gas phase is washed away from carried soluble salts through the liquid penetration film layer, and then is discharged through a demister after reaching the standard through a tower top chimney 2; spraying liquid penetrating through the liquid film layer at the upper part of the integrated tower 1 from the washing spraying layer, wherein the spraying liquid falls into the bottom of the separation layer, then reflows to a clean water tank 5 at the bottom of the separation layer through a pipeline, and then realizes the 2 nd circulation through a washing circulating pump 10; and (3) feeding part of the slurry in the slurry tank at the bottom of the integrated tower into a gypsum whisker preparation tank 4, preparing the gypsum whisker under the action of a formula agent and stirring to obtain the gypsum whisker, arranging a filter pump 9, pumping the gypsum whisker slurry to a filter 10, and refluxing the filtrate into the slurry tank 3, wherein the gypsum whisker F has a product value.

The electrolysis takes graphite as an electrode, and direct current is introduced, and the voltage is 20V.

The implementation effect is as follows: the desulfurization rate is more than or equal to 90 percent, the denitration rate is more than or equal to 90 percent, and the dust removal rate is more than or equal to 90 percent.

Example 3

Example 3 is an example of a desulfurization, denitrification, and dedusting integrated process with split towers.

In FIG. 3, a desulfurization, denitrification and dust removal integrated tower 1, a slurry tank 2, a transition slurry tank 3, a gypsum whisker preparation tank 4, a clear water tank 5, a reflux tank 6, an absorption circulating pump 6, an automatic lime feeding device 7, a vacuum belt filter 8, a gas-liquid separator 9, a vacuum pump 10, a filter 11, an absorption circulating pump 12 and a washing circulating pump 13 are arranged; communication gaps a1, a2, a3, a4 and a5 between the pools, a tower bottom drainage port b1 and a washing water drainage port b 2; flue gas A, purified flue gas B, lime C, washing process water D, ammonia water E, gypsum whisker F and suction filtration tail gas G.

The desulfurization, denitrification and dust removal integrated tower 1 is provided with double circulation and a connected chimney, and the split water tank is divided into a slurry tank 2, a transition slurry tank 3, a gypsum whisker preparation tank 4, a clean water tank 5 and a reflux tank 6; a1, a2, a3, a4 and a5 are communicated gaps among pools, a bottom water outlet b1 and a washing water outlet b 2;

the process comprises the following steps: the flue gas A enters the bottom of a desulfurization, denitrification and dust removal integrated tower 1 and is in countercurrent contact with absorption liquid sprayed from the upper part, the absorption liquid containing ammonia in the tower flows through an electro-catalytic layer in the tower, and normal-temperature catalytic reaction occurs in the surface area of an electro-active substance to enable NOx to generate N₂Meanwhile, sulfur dioxide is absorbed, absorption spray liquid falls into a slurry pool 2 of a water pool beside the integrated tower 1 from a water outlet b1 at the bottom of the tower and is divided into two streams of fluid, one stream of supplemented chemical agent ammonia water E flows back to a backflow pool 6, the other stream overflows into a gypsum whisker preparation pool 4 through a slurry transition pool 3, lime is added, under the action of a formula agent and stirring, gypsum whiskers are prepared, a filter pump 11 is arranged, the gypsum whisker slurry is pumped to a vacuum belt filter 8 to obtain gypsum whiskers F, filtrate is separated and flows back to the backflow pool 6 through a gas-liquid separator 9, vacuum filtration is carried out under the pressure difference provided by a vacuum pump 10, and the vacuum pump pumps and filters tail gas G which is sent to the integrated tower 1 for desulfurization, denitrification and dust removal; adding washing process water D into the clean water tank 5, overflowing part of the clean water to the reflux tank 6, and realizing the 1 st cycle of the collected reflux liquid by an absorption and circulation pump 12; the flue gas after desulfurization and denitrification enters the upper space of the integrated tower 1 through the gas holes on the separation layer, the gas phase is washed away from carried soluble salts through the liquid penetration film layer, and then the gas phase is discharged and purified by a demister through a tower top chimney to reach the standard; spraying liquid penetrating through the liquid film layer at the upper part of the integrated tower 1 from the washing spraying layer, wherein the spraying liquid falls into the bottom of the separation layer, then reflows to a washing water outlet b2 on a clean water tank 5 at the bottom of the tower through a pipeline, and then realizes the 2 nd circulation through a washing circulating pump 13;

the electrolysis takes graphite as an electrode, and direct current is introduced, and the voltage is 20V.

The implementation effect is as follows: the desulfurization rate is more than or equal to 90 percent, the denitration rate is more than or equal to 90 percent, and the dust removal rate is more than or equal to 90 percent.

The invention has the beneficial effects that: (1) the integrated process for desulfurization, denitrification and dust removal is an integral technical system, and the desulfurization, denitrification and dust removal are mutually cooperated, so that the problem of flue gas treatment is solved with high efficiency and low cost; (2) the desulfurization adopts a limestone desulfurization and gypsum whisker co-production process, overcomes the defect of lime-gypsum desulfurization, and takes a high-consumption and high-pollution process as a production process with product value; (3) denitration is wet electrocatalysis, normal-temperature denitration is not limited by temperature; (4) a penetrating liquid film absorption device is adopted for dust removal, so that the problems of entrainment of wet desulphurization mist, entrainment of soluble salt and ammonia escape are solved; (5) small occupied area, low investment cost, easy operation and strong adaptability.