CN111467942A

CN111467942A - Double-tower desulfurization and denitrification system and method with cooperation of ozone oxidation and multistage circulating spraying

Info

Publication number: CN111467942A
Application number: CN202010343532.0A
Authority: CN
Inventors: 钟璐; 杨颖欣; 胡静龄; 刘勇; 胡小吐; 杨森林
Original assignee: Guangdong Jiade Environmental Protection Technology Co Ltd
Current assignee: Guangdong Jiade Environmental Protection Technology Co Ltd
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2020-07-31

Abstract

The invention provides a double-tower desulfurization and denitrification system and method with ozone oxidation cooperated with multistage circulating spraying, wherein the double-tower desulfurization and denitrification system comprises a desulfurization device and a denitrification device connected with the top of the desulfurization device, and the bottom of the desulfurization device is communicated with the bottom of the denitrification device; an ozone generating device is connected to an inlet flue of the desulfurizing device; the inside circulation that divide into along the flue gas flow direction of desulphurization unit sprays district and at least one deck oxidation absorption district in proper order, the oxidation absorption district in be provided with ozone injection apparatus and be located the doctor solution spray set of ozone injection apparatus top. The strong oxidizing property of ozone is adopted to convert the nitric oxide in the flue gas into nitrogen dioxide for removalThe flue gas is subjected to multi-stage circulating spraying and ozone oxidation in coordination in the sulfur device, SO in the flue gas is gradually removed₂And the deep oxidation of the flue gas is realized, so that the concentration of the solution carried in the flue gas is very low, the white smoke phenomenon of a wet desulphurization system is relieved, and the corrosion of equipment is reduced.

Description

Double-tower desulfurization and denitrification system and method with cooperation of ozone oxidation and multistage circulating spraying

Technical Field

The invention belongs to the technical field of flue gas desulfurization and denitration, relates to a double-tower desulfurization and denitration system and method with synergy of ozone oxidation, and particularly relates to a double-tower desulfurization and denitration system and method with synergy of ozone oxidation and multistage circulating spraying.

Background

Nitrogen Oxides (NO)_x) Is one of the main pollution sources of the atmosphere and is also a difficult problem in the treatment of the atmospheric pollution at present. Known as Nitrogen Oxides (NO)_x) Comprising N₂O、NO、NO₂And N₂O₃Etc., wherein the atmosphere is contaminated primarily with NO and NO₂。

NO emitted by human activities_xAlbeit only naturally occurring NO_xAbout 1/10, but the emission concentration is high, so that the site is concentrated and the harm is great. NO_xThe harm to the natural environment and the production and life of human beings caused by the emission mainly comprises: NO_xHas toxic effect on human body; damaging effects on plants: NO_xIs the main reason for forming acid rain and acid mist; NO_xAnd the carbon dioxide and the hydrocarbon form chemical smog to cause secondary pollution. Therefore, the countries have formulated the content of NO_xExhaust emission index, for NO_xThe amount and concentration of the emissions are limited. With the increasing requirement of human on environmental protection, NO is added_xWill become increasingly stringent.

The existing mature denitration process comprises various processes such as a low-nitrogen combustion system, a Selective Catalytic Reduction (SCR) method, a selective non-catalytic reduction (SNCR) method, ozone denitration and the like. Each process has its own advantages and disadvantages and applicable conditions. The best technical means for large coal-fired boilers is the Selective Catalytic Reduction (SCR), and for waste incineration, cement kilns and circulating fluidized bed boilers (CFB), the selective non-catalytic reduction (SNCR) is a relatively economical process. Besides, many units are not suitable for SCR and SNCR, and the ozone oxidation denitration method is just suitable for the units.

Ozone (O)₃) Is a high-energy existing form of oxygen, is colorless, has special odor, is extremely unstable, has peculiar strong oxidizing property, can effectively remove nitrogen oxide, sulfur dioxide, chlorine fluorine organic matter and the like, and can simultaneously sterilize, decontaminate, bleach, deodorize and the like, and the ozone is reduced into (O) in the process of decomposing chemical substances₂) Or generate water (H)₂O), no secondary pollution is generated. In nature, it is mainly produced by lightning, and is a "natural purifying agent". Because of the purifying property of ozone, the adoption of an artificial ozone generator leads the ozone to be widely applied in the water treatment industry. Ozone has high and fast killing rate to bacteria, viruses and other microbes in water, and can eliminate organic compound and other pollutant completely without producing secondary pollution, so that drinking water sterilizing is the main department of ozone application, and tap water industry is the largest market for ozone.

Except for the application in the aspect of water treatment, the ozone can also effectively treat nitrogen oxide pollution, and the process is a circulating cleaning process without catalyst, reducing agent and zero emission. The removal of nitrogen oxides by ozone is widely applied to FCC (catalytic cracking of petrochemical industry), and is an advanced cleaning process with zero absorbent, zero catalyst and zero pollution.

The oxidation capacity of ozone is very strong, and the oxidation-reduction potential of ozone is second to fluorine and is higher than that of hydrogen peroxide, potassium permanganate and the like. In addition, the reaction product of ozone is oxygen, so it is a strong oxidizer that is highly efficient and clean. However, in the application of ozone oxidation denitration engineering, the problems of incomplete oxidation of NO in flue gas, complex byproduct components and the like exist, and the popularization and application of an ozone oxidation method are limited.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an ozone oxidation synergistic multi-stage circulationThe invention relates to a spraying double-tower desulfurization and denitrification system and a method, which firstly adopt the strong oxidizing property of ozone to convert nitric oxide in flue gas into nitrogen dioxide, and then carry out multi-stage circulating spraying and ozone oxidation on the flue gas in a desulfurization device to gradually remove SO in the flue gas₂And the deep oxidation of the flue gas is realized, so that the concentration of the solution carried in the flue gas is very low, the white smoke phenomenon of a wet desulphurization system is relieved, and the corrosion of equipment is reduced.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a double-tower desulfurization and denitrification system with ozone oxidation and multistage circulating spraying, the double-tower desulfurization and denitrification system comprises a desulfurization device and a denitrification device connected with a flue gas outlet of the desulfurization device, a liquid outlet at the bottom of the desulfurization device is connected with the denitrification device, and absorption liquid collected at the bottom of the desulfurization device is introduced into the denitrification device to be used as denitrification liquid.

And an ozone generating device is connected to an inlet flue of the desulfurizing device.

The inside circulation that divide into along the flue gas flow direction of desulphurization unit sprays district and at least one deck oxidation absorption district in proper order, the oxidation absorption district in be provided with ozone injection apparatus and be located the doctor solution spray set of ozone injection apparatus top.

The method firstly adopts the strong oxidizing property of ozone to convert nitric oxide in the flue gas into nitrogen dioxide, and then carries out multi-stage circulating spraying and ozone oxidation in coordination on the flue gas in a desulfurization device to gradually remove SO in the flue gas₂Deep oxidation of the flue gas is realized, so that the concentration of the solution carried in the flue gas is very low, the white smoke phenomenon of a wet desulphurization system is relieved, and equipment corrosion is reduced; adopt two tower structural design, separately go on desulfurization process and denitration process, reduced the competition reaction, the absorption liquid that produces after spraying in the desulphurization unit still can regard as the denitrifier of denitration device to use, and desulfurization efficiency and denitration efficiency can reach more than 95%.

As a preferable technical scheme of the invention, the ozone generating device is connected into an inlet flue of the desulphurization device through an ozone injection pipeline.

Preferably, the outlet end of the ozone injection pipeline faces the flue gas inlet direction, and the flue gas enters the inlet flue and then is in countercurrent contact with ozone.

Preferably, the outlet end of the ozone injection pipeline is provided with an ozone distributor.

Preferably, the ozone generating devices are also respectively and independently connected with the ozone spraying device.

Preferably, the spraying direction of the ozone spraying device is the same as the flow direction of the flue gas.

Preferably, the doctor solution spraying device comprises a doctor solution spraying main pipe and at least one atomizing nozzle uniformly distributed on the doctor solution spraying main pipe, the doctor solution spraying main pipe is respectively and independently connected with a doctor solution storage tank, and the doctor solution storage tank independently conveys the doctor solution to the doctor solution spraying main pipe.

Preferably, a defogging device is arranged between two adjacent oxidation absorption areas.

As a preferable technical scheme of the invention, the circulating spray area comprises a circulating spray tank and a circulating spray layer positioned above the circulating spray tank, and the desulfurizing liquid after being sprayed is collected at the bottom of the desulfurizing device to form the circulating spray tank.

Preferably, the circulating spraying layer comprises a circulating spraying main pipe and at least one atomizing nozzle uniformly distributed on the circulating spraying main pipe, and the circulating spraying pool is connected with the circulating spraying main pipe through a peripheral desulfurization solution circulating pipeline.

Preferably, the liquid outlet of the circulating spray pond is connected with the liquid inlet of the desulfurization liquid storage tank, the absorption liquid collected in the circulating spray pond is sent to the desulfurization liquid spray main pipe through the desulfurization liquid storage tank, and the absorption liquid sprayed by the desulfurization liquid spray main pipe falls into the circulating spray pond.

Preferably, a defogging device is arranged between the circulating spraying area and the adjacent oxidation absorption area above the circulating spraying area.

Preferably, a demisting device is arranged at a flue gas outlet at the top of the desulphurization device.

As a preferable technical scheme of the invention, the interior of the desulfurization device is sequentially divided into a circulating spray zone, a first oxidation absorption zone and a second oxidation absorption zone along the flow direction of flue gas.

Preferably, a first ozone spraying device and a first doctor solution spraying device located above the first ozone spraying device are arranged in the first oxidation absorption area, a second ozone spraying device and a second doctor solution spraying device located above the second ozone spraying device are arranged in the second oxidation absorption area, the ozone generating device is respectively and independently connected with the first ozone spraying device and the second ozone spraying device, and a liquid outlet of the doctor solution storage tank is respectively and independently connected with the first doctor solution spraying device and the second doctor solution spraying device.

Preferably, a first demisting device is arranged between the circulating spraying layer and the first ozone spraying device.

Preferably, a second demisting device is arranged between the first desulfurization solution spraying device and the second ozone spraying device.

Preferably, the flue gas outlet at the top of the desulfurization device is provided with a third demisting device.

As a preferred technical solution of the present invention, the inside of the denitration device includes a denitration liquid circulation tank and at least one denitration liquid spray layer located above the denitration liquid circulation tank, the denitration liquid circulation tank is formed by collecting the sprayed denitration liquid at the bottom of the denitration device, and the denitration liquid circulation tank is respectively and independently connected to the denitration liquid spray layers through an external denitration liquid circulation pipeline.

Preferably, the denitration liquid circulating tank is communicated with the desulfurization liquid circulating tank, and the absorption liquid collected in the desulfurization liquid circulating tank is introduced into the denitration liquid circulating tank to be used as the denitration liquid of the flue gas.

Preferably, the denitration liquid spraying layer comprises a denitration liquid spraying main pipe connected with the denitration liquid circulating pipeline and atomizing nozzles uniformly distributed on the denitration liquid spraying main pipe.

Preferably, a fourth demisting device is arranged at a flue gas outlet at the top of the denitration device.

Preferably, two denitration liquid spraying layers are arranged above the denitration liquid circulating pool.

In a second aspect, the invention provides a double-tower desulfurization and denitrification method with ozone oxidation cooperating with multistage circulating spraying, wherein the double-tower desulfurization and denitrification system of the first aspect is adopted to perform desulfurization and denitrification treatment on flue gas;

the double-tower desulfurization and denitrification method comprises the following steps:

the flue gas enters an inlet flue and then is in contact oxidation with ozone, the oxidized flue gas enters a desulfurization device and sequentially passes through a circulating spray area and each oxidation absorption area, and SO in the flue gas is removed after desulfurization liquid multi-stage spray absorption and ozone oxidation₂And further oxidize NO in the flue gas_x(ii) a The desulfurized flue gas enters a denitration device, and absorption liquid formed after the desulfurization liquid is sprayed flows into the denitration device from the bottom of the desulfurization device to serve as the denitration liquid to carry out circulating spraying denitration on the flue gas.

As a preferable technical scheme, the double-tower desulfurization and denitrification method specifically comprises the following steps:

the method comprises the following steps that (I) ozone is sprayed into an inlet flue by an ozone generating device, flue gas enters the inlet flue and then is in contact oxidation with the ozone, and the oxidized flue gas enters a desulfurization device;

(II) the flue gas sequentially passes through a circulating spraying area and each layer of oxidation absorption area from bottom to top after entering a desulfurization device, and in the circulating spraying area, the flue gas is in countercurrent contact with desulfurization liquid which is sprayed circularly to realize primary desulfurization; the ozone generating device independently introduces ozone to the ozone injection devices of the oxidation absorption areas of each layer, absorption liquid collected in the desulfurization liquid circulating pool is independently sent to the desulfurization liquid spraying device of the oxidation absorption areas through the desulfurization liquid storage tank, and the flue gas is contacted with the desulfurization liquid and the ozone in the oxidation absorption areas of each layer to realize the desulfurization and the oxidation of the flue gas;

(III) allowing the absorption liquid formed after the desulfurization liquid is sprayed to flow into a denitration liquid circulation tank at the bottom of the denitration device from a desulfurization liquid circulation tank at the bottom of the desulfurization device to be used as the denitration liquid, and allowing the desulfurized flue gas to enter the denitration device from the top of the desulfurization device to be in countercurrent contact with the denitration liquid sprayed circularly to be subjected to denitration.

As a preferred aspect of the present inventionIn the step (I), the flow rate of the flue gas is 5000-10000 Nm³H, for example, may be 5000Nm³/h、5500Nm³/h、6000Nm³/h、6500Nm³/h、7000Nm³/h、7500Nm³/h、8000Nm³/h、8500Nm³/h、9000Nm³/h、9500Nm³H or 10000Nm³And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.

Preferably, SO in said flue gas₂The concentration of (A) is 300-2000 mg/Nm³For example, it may be 300mg/Nm³、400mg/Nm³、500mg/Nm³、600mg/Nm³、700mg/Nm³、800mg/Nm³、900mg/Nm³、1000mg/Nm³、1100mg/Nm³、1200mg/Nm³、1300mg/Nm³、1400mg/Nm³、1500mg/Nm³、1600mg/Nm³、1700mg/Nm³、1800mg/Nm³、1900mg/Nm³Or 2000mg/Nm³However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.

Preferably, NO in said flue gas_xThe concentration of (A) is 200-500 mg/Nm³For example, it may be 200mg/Nm³、250mg/Nm³、300mg/Nm³、350mg/Nm³、400mg/Nm³、450mg/Nm³Or 500mg/Nm³However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.

Preferably, the mass flow rate of the ozone sprayed into the inlet flue by the ozone generating device is 2-10 kg/h, for example, 2kg/h, 3kg/h, 4kg/h, 5kg/h, 6kg/h, 7kg/h, 8kg/h, 9kg/h or 10kg/h, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the molar ratio of ozone to NO in the flue gas in the inlet flue is (0.5-0.8): 1, and may be, for example, 0.50:1, 0.52:1, 0.54:1, 0.56:1, 0.58:1, 0.60:1, 0.62:1, 0.64:1, 0.66:1, 0.68:1, 0.70:1, 0.72:1, 0.74:1, 0.76:1, 0.78:1 or 0.80:1, but is not limited to the recited values, and other values not recited in this range are equally applicable.

Preferably, the contact time of the ozone and the flue gas in the inlet flue is 0.5 to 1.5s, for example 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, 1.1s, 1.2s, 1.3s, 1.4s or 1.5s, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

As a preferable technical scheme of the invention, in the step (II), the desulfurization solution is NaOH solution, and the flue gas and the desulfurization solution sprayed circularly are in countercurrent contact reaction to generate Na₂SO₃。

Preferably, the mass flow of ozone introduced into each oxidation absorption zone by the ozone generating device is gradually reduced along the flow direction of the flue gas.

Preferably, the mass flow rate of ozone introduced into each oxidation absorption zone by the ozone generating device is gradually reduced from bottom to top according to a reduction ratio of 20-30%, for example, the mass flow rate is gradually reduced from bottom to top according to a reduction ratio of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, but the ozone generating device is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the flue gas enters the desulfurization device and then sequentially passes through the circulating spray zone, the first oxidation absorption zone and the second oxidation absorption zone from bottom to top.

Preferably, after entering the first oxidation absorption zone, the flue gas is in concurrent contact oxidation with the ozone sprayed by the first ozone spraying device and is simultaneously in countercurrent contact desulfurization with the absorption liquid sprayed by the second desulfurization liquid spraying device.

Preferably, the ozone generator feeds ozone to the first ozone injection device at a mass flow rate of 2-10 kg/h, such as 2kg/h, 3kg/h, 4kg/h, 5kg/h, 6kg/h, 7kg/h, 8kg/h, 9kg/h or 10kg/h, but not limited to the values listed, and other values not listed in the range of values are also applicable.

Preferably, the molar ratio of the ozone injected by the first ozone injecting device to the NO in the flue gas is (0.8-1): 1, and may be, for example, 0.80:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, 0.86:1, 0.87:1, 0.88:1, 0.89:1, 0.90:1, 0.91:1, 0.92:1, 0.93:1, 0.94:1, 0.95:1, 0.96:1, 0.97:1, 0.98:1, 0.99:1 or 1:1, but is not limited to the recited values, and other values in the range of values are also applicable.

Preferably, after entering the second oxidation absorption area, the flue gas is in concurrent contact oxidation with the ozone sprayed by the first ozone spraying device and is simultaneously in countercurrent contact desulfurization with the absorption liquid sprayed by the second desulfurization liquid spraying device.

Preferably, the ozone generator feeds ozone to the first ozone injection device at a mass flow rate of 1.5-5 kg/h, such as 1.5kg/h, 2kg/h, 2.5kg/h, 3kg/h, 3.5kg/h, 4kg/h, 4.5kg/h, or 5kg/h, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

Preferably, the molar ratio of the ozone injected by the second ozone injecting device to the NO in the flue gas is (0.5-0.8): 1, and may be, for example, 0.5:1, 0.52:1, 0.54:1, 0.56:1, 0.58:1, 0.60:1, 0.62:1, 0.64:1, 0.66:1, 0.68:1, 0.70:1, 0.72:1, 0.74:1, 0.76:1, 0.78:1 or 0.8:1, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

In a preferred embodiment of the present invention, in step (III), the absorbing solution formed after spraying the desulfurization solution contains Na produced by the reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium sulfate reaches more than 40 wt%, the absorption liquid is introduced into the denitration liquid circulation tank from the desulfuration liquid circulation tank to be used as the denitration liquid of the flue gas, and Na in the absorption liquid₂SO₃With NO in the flue gas₂Redox reactions occur, for example up to 40 wt.%, 41 wt.%, 42 wt.%, 43 wt.%, 44 wt.%, 45 wt.%, 46 wt.%, 47 wt.%, 48 wt.%, 49 wt.% or 50 wt.%, but not limited to the values recited, and other values not recited within this range are equally applicable.

Preferably, said Na₂SO₃And NO₂The molar ratio of (1 to 2):1 may be, for example, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1, but is not limited to the enumerated values, and other values not enumerated within the numerical range are also applicable.

Preferably, the liquid-gas ratio of the absorption liquid to the flue gas is (5-8): 1, and may be, for example, 5.0:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1, 6.0:1, 6.2:1, 6.4:1, 6.6:1, 6.8:1, 7.0:1, 7.2:1, 7.4:1, 7.6:1, 7.8:1 or 8.0:1, but is not limited to the enumerated values, and other non-enumerated values within the numerical range are also applicable.

The system refers to an equipment system, or a production equipment.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, firstly, the strong oxidizing property of ozone is adopted to convert nitric oxide in the flue gas into nitrogen dioxide, then the flue gas is subjected to multi-stage circulating spraying and ozone oxidation in cooperation in a desulfurization device, SO that SO2 in the flue gas is gradually removed, and the deep oxidation of the flue gas is realized, SO that the concentration of a solution carried in the flue gas is very low, the white smoke phenomenon of a wet desulfurization system is relieved, and the corrosion of equipment is reduced;

(2) the invention adopts the design of a double-tower structure, the desulfurization process and the denitration process are separately carried out, the competitive reaction is reduced, the absorption liquid generated after being sprayed in the desulfurization device can also be used as the denitration agent of the denitration device, and the desulfurization efficiency and the denitration efficiency can reach more than 95 percent.

Drawings

FIG. 1 is a schematic diagram showing the results of a two-stage cycle twin-tower SOx/NOx system provided in example 1 of the present invention;

fig. 2 is a schematic diagram of the results of the three-stage circulating double-tower desulfurization and denitrification system provided in embodiment 5 of the present invention.

Wherein, 1-inlet flue; 2-an ozone generating device; 3-a desulfurization unit; 4-circulating spraying area; 5-circulating a spray pond; 6-a desulfurization liquid circulating pipeline; 7-circulating a spraying layer; 8-a first oxidation absorption zone; 9-a first ozone injection device; 10-a first desulfurization liquid spray device; 11-a second oxidation absorption zone; 12-a second ozone injection device; 13-a second desulfurization liquid spraying device; 14-a doctor solution storage tank; 15-a first demisting device; 16-a second defogging device; 17-a third defogging device; 18-a denitrator; 19-a denitration liquid circulating tank; 20-a first denitration liquid spraying layer; 21-a second denitration liquid spraying layer; 22-a first denitration liquid circulation pipeline; 23-a second denitration liquid circulation pipeline; 24-a first circulation pump; 25-a second circulation pump; 26-fourth demisting device.

Detailed Description

It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

Example 1

This embodiment provides a two tower SOx/NOx control systems that ozone oxidation cooperates two-stage circulation to spray, two tower SOx/NOx control systems as shown in FIG. 1, including desulphurization unit 3 and with 3 flue gas exit linkage's of desulphurization unit denitrification facility 18, denitrification facility 18 is connected to 3 bottom liquid outlets of desulphurization unit, the absorption liquid that 3 bottoms of desulphurization unit were collected lets in denitrification facility 18 in use as the denitration liquid.

Connect ozone generating device 2 on desulphurization unit 3's the inlet flue 1, in ozone generating device 2 inserted desulphurization unit 3's the inlet flue 1 through the ozone injection pipeline, the outlet end of ozone injection pipeline was towards the flue gas direction of admitting air, and the flue gas gets into and contacts with ozone countercurrent after inlet flue 1, and the outlet end of ozone injection pipeline is provided with the ozone uniform distributor.

The inside of the desulphurization device 3 is divided into a circulating spray zone 4 and a first oxidation absorption zone 8 in sequence along the flow direction of the flue gas.

The circulating spray area 4 comprises a circulating spray pool 5 and a circulating spray layer 7 positioned above the circulating spray pool 5, and the tower bottom of the desulphurization device 3 collects sprayed desulphurization liquid to form the circulating spray pool 5. The circulating spraying layer 7 comprises a circulating spraying main pipe and at least one atomizing nozzle uniformly distributed on the circulating spraying main pipe, the circulating spraying pool 5 is connected with the circulating spraying main pipe through an external desulfurization liquid circulating pipeline 6, and a liquid outlet of the circulating spraying pool 5 is connected with a liquid inlet of a desulfurization liquid storage tank 14.

The first oxidation absorption area 8 is internally provided with a first ozone spraying device 9 and a first desulfurization liquid spraying device 10 positioned above the first ozone spraying device 9, the ozone generating device 2 is connected with the first ozone spraying device 9, the liquid outlet of the desulfurization liquid storage tank 14 is connected with the first desulfurization liquid spraying device 10, and the first desulfurization liquid spraying device 10 comprises a desulfurization liquid spraying main pipe connected with the desulfurization liquid storage tank 14 and at least one atomizing nozzle uniformly distributed on the desulfurization liquid spraying main pipe. The absorption liquid collected in the circulating spray tank 5 is sent into the main desulfurization liquid spray pipe through the desulfurization liquid storage tank 14, and the absorption liquid sprayed by the main desulfurization liquid spray pipe falls into the circulating spray tank 5.

A first demisting device 15 is arranged between the circulating spraying layer 7 and the first ozone injection device 9, and a third demisting device 17 is arranged at a flue gas outlet at the top of the desulfurizing device 3.

Denitration device 18 is inside including being located the denitration liquid circulation pond 19 at the bottom of the tower, and denitration liquid circulation pond 19 top has set gradually first denitration liquid along the flue gas flow direction and has sprayed layer 20 and second denitration liquid and spray layer 21. The denitration liquid circulating tank 19 is formed after the sprayed denitration liquid is collected at the bottom of the denitration device 18, and the denitration liquid circulating tank 19 is respectively and independently connected with a first denitration liquid spraying layer 20 and a second denitration liquid spraying layer 21 through a first denitration liquid circulating pipeline 22 and a second denitration liquid circulating pipeline 23 which are arranged outside. The first denitration liquid circulation pipeline 22 is provided with a first circulation pump 24, and the second denitration liquid circulation pipeline 23 is provided with a second circulation pump 25. The flue gas outlet at the top of the tower of the denitration device 18 is provided with a fourth demisting device 26.

The denitration liquid circulating tank 19 is communicated with the desulfurization liquid circulating tank, and the absorption liquid collected in the desulfurization liquid circulating tank is introduced into the denitration liquid circulating tank 19 to be used as the denitration liquid of the flue gas.

Example 2

In this embodiment, the desulfurization and denitrification system provided in embodiment 1 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂At a concentration of 320mg/Nm³NO in flue gas_xAt a concentration of 220mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 2kg/h of ozone into the inlet flue 1, and the flue gas is 5000Nm³After entering an inlet flue 1, the flow of the gas/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.5:1, the contact time is 1s, and the oxidized flue gas enters a desulfurization device 3;

(2) the flue gas enters a desulphurization device 3 and then enters a circulating spray area 4, and the flue gas and a desulphurization solution NaOH solution which is sprayed circularly in the circulating spray area 4 are in countercurrent contact reaction to generate Na₂SO₃Primary desulfurization is realized;

(3) the flue gas after the primary desulfurization continuously rises and enters a first oxidation absorption zone 8In the absorption zone 8, 2kg/h of ozone is introduced into the first ozone injection device 9 by the ozone generation device 2, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.8: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the first oxidation absorption area 8;

(4) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 40 wt%, introducing the absorption liquid from the desulfurization liquid circulating pool into the denitration liquid circulating pool 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 5: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration is 10.2mg/Nm³，NO_x(in terms of NO) concentration of 21mg/Nm³The desulfurization rate was calculated to be 96.8% and the denitration rate was calculated to be 90.5%.

Example 3

In this embodiment, the desulfurization and denitrification system provided in embodiment 1 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂Has a concentration of 560mg/Nm³NO in flue gas_xAt a concentration of 260mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 4kg/h of ozone into the inlet flue 1, and the smoke gas is 6000Nm³After entering an inlet flue 1, the flow of the ozone/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.55:1, the contact time is 0.7s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 4kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.82: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the first oxidation absorption area 8;

(4) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 43 wt%, introducing the absorption liquid from the desulfurization liquid circulating tank into the denitration liquid circulating tank 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1.2:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 6: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration is 15mg/Nm³，NO_x(in terms of NO) concentration of 24.5mg/Nm³The desulfurization rate was calculated to be 97.3% and the denitration rate was calculated to be 90.6%.

Example 4

In this embodiment, the desulfurization and denitrification system provided in embodiment 1 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂The concentration of (b) is 850mg/Nm³NO in flue gas_xAt a concentration of 310mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 5kg/h of ozone into the inlet flue 1, and the flue gas is 7000Nm³After entering an inlet flue 1, the flow of the ozone/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.6:1, the contact time is 0.5s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 5kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.84: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the first oxidation absorption area 8;

(4) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sulfur-containing waste water reaches 45 wt%, the absorption liquid is communicated with a desulfurization liquid circulating tankThe Na in the absorption liquid is used as the denitration liquid of the flue gas in a denitration liquid circulating pool 19₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1.7:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 7: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration is 11mg/Nm³，NO_x(in terms of NO) concentration 35mg/Nm³The desulfurization rate was calculated to be 98.7% and the denitration rate was calculated to be 88.7%.

Example 5

The inside of the desulphurization device 3 is divided into a circulating spray zone 4, a first oxidation absorption zone 8 and a second oxidation absorption zone 11 in sequence along the flow direction of the flue gas.

The circulating spray area 4 comprises a circulating spray pool 5 and a circulating spray layer 7 positioned above the circulating spray pool 5, and the tower bottom of the desulphurization device 3 collects sprayed desulphurization liquid to form the circulating spray pool 5. The circulating spraying layer 7 comprises a circulating spraying main pipe and at least one atomizing nozzle uniformly distributed on the circulating spraying main pipe, the circulating spraying pool 5 is connected with the circulating spraying main pipe through an external desulfurization liquid circulating pipeline 6, and a liquid outlet of the circulating spraying pool 5 is connected with a liquid outlet of a desulfurization liquid storage tank 14.

A first ozone injection device 9 and a first desulfurization liquid spray device 10 positioned above the first ozone injection device 9 are arranged in the first oxidation absorption area 8; the second oxidation absorption area 11 is internally provided with a second ozone injection device 12 and a second desulfurization liquid spray device 13 positioned above the second ozone injection device 12. The ozone generating device 2 is respectively and independently connected with a first ozone spraying device 9 and a second ozone spraying device 12, the liquid outlet of a desulfurization liquid storage tank 14 is respectively and independently connected with a first desulfurization liquid spraying device 10 and a second desulfurization liquid spraying device 13, absorption liquid collected in the circulating spray pond 5 is respectively sent into the first desulfurization liquid spraying device 10 and the second desulfurization liquid spraying device 13 through the desulfurization liquid storage tank 14, and the absorption liquid sprayed by the first desulfurization liquid spraying device 10 and the second desulfurization liquid spraying device 13 falls into the circulating spray pond 5.

A first demisting device 15 is arranged between the circulating spraying layer 7 and the first ozone injection device 9, a second demisting device 16 is arranged between the first desulfurization liquid spraying device 10 and the second ozone injection device 12, and a third demisting device 17 is arranged at a flue gas outlet at the top of the desulfurization device 3.

Example 6

In this embodiment, the desulfurization and denitrification system provided in embodiment 5 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂At a concentration of 500mg/Nm³In the flue gasNO_xAt a concentration of 230mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 2kg/h of ozone into the inlet flue 1, and the flue gas is 5000Nm³After entering an inlet flue 1, the flow of the ozone/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.5:1, the contact time is 1.5s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 2kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.8: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the primary desulfurization and oxidation of the flue gas are simultaneously realized in the first oxidation absorption zone 8;

(4) the flue gas continuously rises to enter a second oxidation absorption area 11, 1.6kg/h of ozone is introduced into a second ozone injection device 12 by an ozone generation device 2 in the second oxidation absorption area 11, the ozone injected by the second ozone injection device 12 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the second ozone injection device 12 to NO in the flue gas is 0.5: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the second desulfurization liquid spraying device 13, the desulfurization liquid is sprayed by the second desulfurization liquid spraying device 13 and is in countercurrent contact with the flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid fallsThe flue gas enters a desulfurization liquid circulation tank, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the second oxidation absorption zone 11;

(5) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 40 wt%, introducing the absorption liquid from the desulfurization liquid circulating pool into the denitration liquid circulating pool 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 5: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration was 13.5mg/Nm³，NO_x(in terms of NO) concentration of 24mg/Nm³The desulfurization rate was calculated to be 97.3%, and the denitration rate was calculated to be 89.5%.

Example 7

In this embodiment, the desulfurization and denitrification system provided in embodiment 5 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂At a concentration of 1000mg/Nm³NO in flue gas_xAt a concentration of 350mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 5kg/h of ozone into the inlet flue 1, and the smoke gas is 6000Nm³After entering an inlet flue 1, the flow of the ozone/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.6:1, the contact time is 1.3s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the primary desulfurization continuously rises and enters the first oxidation absorption zone 8, and is in the first oxidation absorption zone 8The ozone generating device 2 feeds 5kg/h of ozone into the first ozone spraying device 9, the ozone sprayed by the first ozone spraying device 9 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone sprayed by the first ozone spraying device 9 to NO in the flue gas is 0.84: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the primary desulfurization and oxidation of the flue gas are simultaneously realized in the first oxidation absorption zone 8;

(4) the flue gas continuously rises to enter a second oxidation absorption area 11, 3.5kg/h of ozone is introduced into a second ozone injection device 12 by an ozone generation device 2 in the second oxidation absorption area 11, the ozone injected by the second ozone injection device 12 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the second ozone injection device 12 to NO in the flue gas is 0.6: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the second desulfurization liquid spraying device 13, the desulfurization liquid is sprayed by the second desulfurization liquid spraying device 13 and is in countercurrent contact with the flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating tank, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the second oxidation absorption area 11;

(5) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 42 wt%, introducing the absorption liquid from the desulfurization liquid circulating pool into the denitration liquid circulating pool 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1.2:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 6: 1.

By desulfurization and denitrificationThe treated flue gas is discharged from the top of the denitration tower, and then is sampled and detected for SO₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration is 24mg/Nm³，NO_x(in terms of NO) concentration of 34mg/Nm³The desulfurization rate was calculated to be 97.6% and the denitration rate was calculated to be 90.3%.

Example 8

In this embodiment, the desulfurization and denitrification system provided in embodiment 5 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂Has a concentration of 1200mg/Nm³NO in flue gas_xAt a concentration of 380mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 7kg/h of ozone into the inlet flue 1, and the flue gas is 8000Nm³After entering an inlet flue 1, the flow of the ozone/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.7:1, the contact time is 1.2s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 7kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.86: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the primary desulfurization and oxidation of the flue gas are simultaneously realized in the first oxidation absorption zone 8;

(4) the smoke gas continuously rises and enters the second oxidation absorption area 11, and the smell is generated in the second oxidation absorption area 11The oxygen generating device 2 feeds 5.6kg/h of ozone into the second ozone injection device 12, the ozone injected by the second ozone injection device 12 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the second ozone injection device 12 to NO in the flue gas is 0.7: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the second desulfurization liquid spraying device 13, the desulfurization liquid is sprayed by the second desulfurization liquid spraying device 13 and is in countercurrent contact with the flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating tank, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the second oxidation absorption area 11;

(5) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 45 wt%, introducing the absorption liquid from the desulfurization liquid circulating pool into the denitration liquid circulating pool 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1.5:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 7: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration was 19mg/Nm³，NO_x(in terms of NO) concentration 33mg/Nm³The desulfurization rate was calculated to be 98.4% and the denitration rate was calculated to be 91.3%.

Example 9

In this embodiment, the desulfurization and denitrification system provided in embodiment 5 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂The concentration of (b) is 1560mg/Nm³NO in flue gas_xHas a concentration of 430mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 9kg/h of ozone into the inlet flue 1, and the flue gas is 9000Nm³Flow rate of/hAfter entering an inlet flue 1, the flue gas is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.75:1, the contact time is 1s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 9kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 0.88: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the primary desulfurization and oxidation of the flue gas are simultaneously realized in the first oxidation absorption zone 8;

(4) the flue gas continuously rises to enter a second oxidation absorption area 11, 7.2kg/h of ozone is introduced into a second ozone injection device 12 by an ozone generation device 2 in the second oxidation absorption area 11, the ozone injected by the second ozone injection device 12 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the second ozone injection device 12 to NO in the flue gas is 0.75: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the second desulfurization liquid spraying device 13, the desulfurization liquid is sprayed by the second desulfurization liquid spraying device 13 and is in countercurrent contact with the flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating tank, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the second oxidation absorption area 11;

(5) the flue gas is discharged from the top of the desulfurization device 3 and enters the denitration device 18, and the desulfurization liquid is sprayed to form absorptionThe liquid contains Na produced by the reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium aluminate reaches 48 wt%, the absorption liquid is introduced into a denitration liquid circulation tank 19 from a desulfurization liquid circulation tank to be used as the denitration liquid of the flue gas, and Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 1.8:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 7.5: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration was 14mg/Nm³，NO_x(in terms of NO) concentration 33mg/Nm³The desulfurization rate was calculated to be 99.1% and the denitration rate was calculated to be 92.3%.

Example 10

In this embodiment, the desulfurization and denitrification system provided in embodiment 5 is used to perform desulfurization and denitrification treatment on flue gas, SO in the flue gas₂At a concentration of 1980mg/Nm³NO in flue gas_xAt a concentration of 500mg/Nm³The processing method specifically comprises the following steps:

(1) the ozone generating device 2 sprays 10kg/h of ozone into the inlet flue 1, and the smoke gas is 10000Nm³After entering an inlet flue 1, the flow of the flow/h is in contact oxidation with ozone, the molar ratio of the ozone to NO in the flue gas is 0.8:1, the contact time is 0.8s, and the oxidized flue gas enters a desulfurization device 3;

(3) the flue gas after the preliminary desulfurization continuously rises and enters a first oxidation absorption area 8, 10kg/h of ozone is introduced into a first ozone injection device 9 by an ozone generation device 2 in the first oxidation absorption area 8, the ozone injected by the first ozone injection device 9 is in downstream contact with the flue gas to realize the oxidation of the flue gas, and the molar ratio of the ozone injected by the first ozone injection device 9 to NO in the flue gas is 1:1(ii) a The desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the first desulfurization liquid spraying device 10, the desulfurization liquid is sprayed by the first desulfurization liquid spraying device 10 and is in countercurrent contact with flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating groove, and the primary desulfurization and oxidation of the flue gas are simultaneously realized in the first oxidation absorption zone 8;

(4) the flue gas continuously rises to enter a second oxidation absorption area 11, in the second oxidation absorption area 11, ozone of 8kg/h is introduced into a second ozone injection device 12 by an ozone generation device 2, the ozone injected by the second ozone injection device 12 is in downstream contact with the flue gas to realize flue gas oxidation, and the molar ratio of the ozone injected by the second ozone injection device 12 to NO in the flue gas is 0.8: 1; the desulfurization liquid storage tank 14 conveys desulfurization liquid (NaOH solution) to the second desulfurization liquid spraying device 13, the desulfurization liquid is sprayed by the second desulfurization liquid spraying device 13 and is in countercurrent contact with the flue gas to realize desulfurization, and the desulfurization liquid and residual SO in the flue gas in the spraying process₂Further reaction to form Na₂SO₃The obtained absorption liquid falls into a desulfurization liquid circulating tank, and the desulfurization and the oxidation of the flue gas are simultaneously realized in the second oxidation absorption area 11;

(5) the flue gas is discharged from the top of the desulfurization device 3 and enters a denitration device 18, and absorption liquid formed after the desulfurization liquid is sprayed comprises Na generated by reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium hydroxide reaches 50 wt%, introducing the absorption liquid from the desulfurization liquid circulating pool into the denitration liquid circulating pool 19 to be used as the denitration liquid of the flue gas, wherein Na in the absorption liquid₂SO₃With NO in the flue gas₂Oxidation-reduction reaction takes place, Na₂SO₃And NO₂The molar ratio of the absorption liquid to the flue gas is 2:1, and the liquid-gas ratio of the absorption liquid to the flue gas is 8: 1.

The flue gas after desulfurization and denitrification treatment is discharged from the top of the denitrification tower, and then the SO in the flue gas is sampled and detected₂And NO_x(in terms of NO), sampling SO in flue gas₂The concentration is 26mg/Nm³，NO_x(in terms of NO) concentration of 44mg/Nm³CalculatingThe desulfurization rate was 98.7%, and the denitration rate was 91.2%.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims

1. A double-tower desulfurization and denitrification system with ozone oxidation cooperated with multistage circulating spraying is characterized by comprising a desulfurization device and a denitrification device connected with a flue gas outlet of the desulfurization device, wherein a liquid outlet at the bottom of the desulfurization device is connected with the denitrification device, and absorption liquid collected at the bottom of the desulfurization device is introduced into the denitrification device to be used as denitrification liquid;

an ozone generating device is connected to an inlet flue of the desulfurizing device;

2. The double-tower desulfurization and denitrification system according to claim 1, wherein the ozone generating device is connected into an inlet flue of the desulfurization device through an ozone injection pipeline;

preferably, the outlet end of the ozone injection pipeline faces the flue gas inlet direction, and the flue gas enters the inlet flue and then is in countercurrent contact with ozone;

preferably, the outlet end of the ozone injection pipeline is provided with an ozone distributor;

preferably, the ozone generating devices are also respectively and independently connected with the ozone spraying devices;

preferably, the spraying direction of the ozone spraying device is the same as the flow direction of the flue gas;

preferably, the doctor solution spraying device comprises a doctor solution spraying main pipe and at least one atomizing nozzle uniformly distributed on the doctor solution spraying main pipe, the doctor solution spraying main pipe is respectively and independently connected with a doctor solution storage tank, and the doctor solution storage tank independently conveys the doctor solution to the doctor solution spraying main pipe;

3. The double-tower desulfurization and denitrification system according to claim 1 or 2, wherein the circulating spray zone comprises a circulating spray tank and a circulating spray layer positioned above the circulating spray tank, and the desulfurization device collects and sprays desulfurization solution at the bottom of the tower to form the circulating spray tank;

preferably, the circulating spraying layer comprises a circulating spraying main pipe and at least one atomizing nozzle uniformly distributed on the circulating spraying main pipe, and the circulating spraying pool is connected with the circulating spraying main pipe through an external desulfurization solution circulating pipeline;

preferably, the liquid outlet of the circulating spray pond is connected with the liquid inlet of the desulfurization liquid storage tank, the absorption liquid collected in the circulating spray pond is sent to the desulfurization liquid spray main pipe through the desulfurization liquid storage tank, and the absorption liquid sprayed by the desulfurization liquid spray main pipe falls into the circulating spray pond;

preferably, a demisting device is arranged between the circulating spraying area and the adjacent oxidation absorption area above the circulating spraying area;

4. The double-tower desulfurization and denitrification system according to any one of claims 1-3, wherein the interior of the desulfurization device is divided into a circulating spray zone, a first oxidation absorption zone and a second oxidation absorption zone in sequence along the flow direction of flue gas;

preferably, a first ozone spraying device and a first doctor solution spraying device located above the first ozone spraying device are arranged in the first oxidation absorption area, a second ozone spraying device and a second doctor solution spraying device located above the second ozone spraying device are arranged in the second oxidation absorption area, the ozone generating device is respectively and independently connected with the first ozone spraying device and the second ozone spraying device, and a liquid outlet of the doctor solution storage tank is respectively and independently connected with the first doctor solution spraying device and the second doctor solution spraying device;

preferably, a first demisting device is arranged between the circulating spraying layer and the first ozone spraying device;

preferably, a second demisting device is arranged between the first desulfurization liquid spraying device and the second ozone spraying device;

5. The double-tower desulfurization and denitrification system according to any one of claims 1-4, wherein the denitrification device comprises a denitrification liquid circulation tank and at least one denitrification liquid spraying layer positioned above the denitrification liquid circulation tank, the denitrification liquid circulation tank is formed by collecting sprayed denitrification liquid at the bottom of the denitrification device, and the denitrification liquid circulation tank is respectively and independently connected with the denitrification liquid spraying layer through an external denitrification liquid circulation pipeline;

preferably, the denitration liquid circulating tank is communicated with the desulfurization liquid circulating tank, and the absorption liquid collected in the desulfurization liquid circulating tank is introduced into the denitration liquid circulating tank to be used as the denitration liquid of the flue gas;

preferably, the denitration liquid spraying layer comprises a denitration liquid spraying main pipe connected with the denitration liquid circulating pipeline and atomizing nozzles uniformly distributed on the denitration liquid spraying main pipe;

preferably, a fourth demisting device is arranged at a flue gas outlet at the top of the denitration device;

6. A double-tower desulfurization and denitrification method with ozone oxidation cooperated with multistage circulating spraying is characterized in that the double-tower desulfurization and denitrification system of any one of claims 1 to 5 is adopted to perform desulfurization and denitrification treatment on flue gas;

7. The double-tower desulfurization and denitrification method according to claim 6, wherein the double-tower desulfurization and denitrification method specifically comprises the following steps:

8. The double-tower desulfurization and denitrification method according to claim 7, wherein in the step (I), the flow rate of the flue gas is 5000-10000 Nm³/h；

Preferably, SO in said flue gas₂Is rich inThe degree of the reaction is 300 to 2000mg/Nm³；

Preferably, NO in said flue gas_xThe concentration of (A) is 200-500 mg/Nm³；

Preferably, the mass flow of the ozone sprayed into the inlet flue by the ozone generating device is 2-10 kg/h;

preferably, the molar ratio of the ozone in the inlet flue to NO in the flue gas is (0.5-0.8): 1;

preferably, the contact time of the ozone in the inlet flue and the flue gas is 0.5-1.5 s.

9. The double-tower desulfurization and denitrification method according to claim 7 or 8, wherein in the step (II), the desulfurization solution is NaOH solution, and the flue gas and the desulfurization solution sprayed in a circulating manner are subjected to countercurrent contact reaction to generate Na₂SO₃；

Preferably, the mass flow of ozone introduced into each oxidation absorption zone by the ozone generating device is gradually reduced along the flow direction of the flue gas;

preferably, the mass flow of ozone introduced into each oxidation absorption zone by the ozone generating device is gradually reduced from bottom to top according to a reduction ratio of 20-30%;

preferably, the flue gas enters the desulfurization device and then sequentially passes through the circulating spray zone, the first oxidation absorption zone and the second oxidation absorption zone from bottom to top;

preferably, after entering the first oxidation absorption zone, the flue gas is in concurrent contact with ozone sprayed by the first ozone spraying device for oxidation and is simultaneously in countercurrent contact with absorption liquid sprayed by the second desulfurization liquid spraying device for desulfurization;

preferably, the mass flow of the ozone introduced into the first ozone injection device by the ozone generation device is 2-10 kg/h;

preferably, the molar ratio of the ozone sprayed by the first ozone spraying device to NO in the flue gas is (0.8-1): 1;

preferably, after entering the second oxidation absorption area, the flue gas is in concurrent contact with and oxidation of ozone sprayed by the first ozone spraying device and is simultaneously in countercurrent contact with and desulfurization of absorption liquid sprayed by the second desulfurization liquid spraying device;

preferably, the mass flow rate of ozone introduced into the second ozone injection device by the ozone generation device is 1.5-8 kg/h;

preferably, the molar ratio of the ozone sprayed by the second ozone spraying device to NO in the flue gas is (0.5-0.8): 1.

10. The twin-tower desulfurization and denitrification method according to any one of claims 7 to 9, wherein in step (III), the absorption solution formed after spraying the desulfurization solution contains Na produced by the reaction₂SO₃And incompletely reacted NaOH, and Na in the absorption liquid formed after the desulfurization liquid is sprayed₂SO₃When the concentration of the sodium sulfate reaches more than 40 wt%, the absorption liquid is introduced into the denitration liquid circulation tank from the desulfuration liquid circulation tank to be used as the denitration liquid of the flue gas, and Na in the absorption liquid₂SO₃With NO in the flue gas₂Carrying out oxidation-reduction reaction;

preferably, said Na₂SO₃And NO₂The molar ratio of (1-2) to (1);

preferably, the liquid-gas ratio of the absorption liquid to the flue gas is (5-8): 1.