CN111744330A - Desulfurization and denitrification cooperative absorption integrated equipment and method - Google Patents

Abstract

The invention relates to an integrated process and equipment for desulfurization and denitrification synergistic absorption. The processes involved relate to the concentration and specific proportions of nitrogen oxides and sulphur dioxide in the exhaust gas, absorbents, etc.; the related equipment comprises a feeding device, an auxiliary reaction device, an absorption device and a gas-liquid separation device; the feeding device is communicated with the reaction device and the absorption device, and the absorption device is communicated with the gas-liquid separation device; the reaction device is mainly used for generating nitrogen dioxide, including but not limited to generating nitrogen dioxide by arc discharge, and generating nitrogen dioxide by oxidizing nitrogen monoxide in the waste gas; the absorption device is an absorption tower or a microreactor, preferably a microreactor, and more preferably a microdispersion reactor; in the reaction device, the waste gas of specific process conditions is mixed with absorbent to react and be absorbed and removed. The process and the equipment for synergistic absorption of the nitrogen oxides and the sulfides have the advantages of simple process, high absorption efficiency, no need of introducing other substances such as catalysts into a reaction system, realization of resource utilization of waste gas and the like.

Description

Desulfurization and denitrification cooperative absorption integrated equipment and method

Technical Field

The invention belongs to the technical field of flue gas treatment, and relates to integrated equipment and a method for desulfurization and denitrification synergistic absorption.

Background

In recent years, with the increasing pollution caused by the emission of nitrogen oxides and sulfides, the environmental protection requirements of the national environmental protection department on the emission of industrial flue gas are higher and higher. The national Standard for the discharge of pollutants for coking chemical industry stipulates: (iii) implementation of NO in Coke oven flue gas by existing and newly built enterprises in general region from 1 month to 1 day of 2015_x≤500mg/m³、SO₂≤50mg/m³. The coal-fired coke oven project of the key control area executes the special emission limit value of the atmospheric pollutants, namely the NO in the flue waste gas of the coke oven_x≤150mg/m³、SO₂≤30mg/m³(ii) a The partial channel city begins to implement the ultra-low emission standard and requires NO_x≤100mg/m³。

The main flue gas desulfurization technologies at present comprise a limestone-gypsum wet flue gas desulfurization technology, a seawater flue gas desulfurization technology, a magnesium oxide flue gas desulfurization technology and the like, and although the technologies have higher desulfurization efficiency, the technologies have the defects of difficult treatment of desulfurization byproducts, high investment cost and the like; high-efficiency SO removal by ammonia flue gas desulfurization technology₂Meanwhile, the recycling of sulfur element can be realized, but the intermediate product ammonium sulfite in the absorption process is unstable, and the problem of how to economically and efficiently oxidize the ammonium sulfite into a stable ammonium sulfate product still exists.

The flue gas denitration technology mainly comprises a dry method and a wet method. The dry process refers to the conversion of NOx in flue gas to harmless N using a reducing agent₂And H₂O, the SCR method is most widely applied, the denitration efficiency can reach more than 90 percent, but the catalyst is expensive and difficult to treat after inactivation, so that the investment and operation cost is higher; the wet process is to oxidize NO to NO using an oxidizing agent₂Then absorbing with water or alkaline solution to solve the problem of adding extra catalyst in dry method, but adopting ammonia water, alkali solution and other absorbentsThe absorption efficiency is low, the flue gas cannot reach the standard of qualified emission after treatment, and although the absorption efficiency is high, the treatment cost is expensive by adopting absorbents such as sulfurous acid press, sodium sulfite and the like.

The simultaneous desulfurization and denitrification technology for flue gas can be divided into a combined desulfurization and denitrification technology and a simultaneous desulfurization and denitrification technology according to a removal mechanism. The combined desulfurization and denitrification technology is an integrated technology formed by integrating a single desulfurization technology and a single denitrification technology, for example, the traditional combined selective catalytic reduction denitrification (SCR) + limestone/gypsum Wet Flue Gas Desulfurization (WFGD) process has high desulfurization and denitrification efficiency, but the system is complex, the occupied area is large, the investment and operation cost are high, and sulfur and nitrogen elements are not recycled; the simultaneous desulfurization and denitrification technology refers to that SO in the flue gas is treated by using a reaction reagent in one process₂And NOx is eliminated simultaneously, the technology has the characteristics of compact structure, low operating cost and the like, but the treated flue gas is difficult to reach the standard and is discharged due to equipment limitation.

CN110201512A discloses a method for simultaneously desulfurizing and denitrating red mud, which comprises the steps of mixing flue gas to be treated with slurry obtained by mixing part of red mud with water to perform first desulfurization and denitration, then performing sedimentation treatment on the slurry, mixing the obtained supernatant with the rest of red mud, and then performing second desulfurization and denitration treatment on the mixture with the flue gas subjected to ozone oxidation, wherein the total desulfurization efficiency is higher than 95%, and the total denitration efficiency reaches 60-80%.

CN110052139A provides a flue gas desulfurization and denitration device and method, the flue gas desulfurization and denitration device comprises an ozone generation unit, a desulfurization and denitration unit, a flue gas post-treatment unit and SO which are connected in sequence₂The removal rate of the catalyst is as high as 99.2 percent, and NO_xThe removal rate of the catalyst is as high as 93.9 percent; but the desulfurization and denitrification unit of the device comprises 2-4 desulfurization and denitrification towers which are connected in series, each desulfurization and denitrification tower comprises 2-6 spraying layers, and each spraying layer is controlled by an independent circulating pump to spray liquid flowThe process is complex, the floor area of the equipment is large, meanwhile, the spraying liquid consists of water, absorbent and absorption aid, the treated product contains various substances, and the post-treatment is difficult.

Liufang (Xiangtan university Master thesis 2013) performs alkali liquor absorption research of desulfurization and denitrification in small-sized sieve-plate tower mainly by matching NO₂Regulating NO_xThe degree of oxidation, but the process of controlling the ratio of nitrogen oxides and sulfur dioxide is less studied.

Domestic equipment patents or applied patents related to desulfurization and denitrification integration are very large in number, and the mainly adopted absorption equipment is mainly an improved absorption tower, so that the occupied area of the equipment is large comprehensively. In a common incinerator, the temperature is low, and the main pollutant in the flue gas is SO₂Derived from the sulfur in the coal. In the treatment of the flue gas, the flue gas is mainly absorbed by lye. Alkali liquor to SO₂The absorption reaction of (2) is very fast, sulfite is generated in the absorption liquid, but the reaction rate of further oxidizing sulfite into sulfate is low, and a catalyst and an auxiliary oxidation device are needed. In the coke generation, the temperature of the incinerator is high, and S in the flue gas except the fuel is converted into SO₂Besides, N in the air is also converted into N₂By oxidation to NO_x. This portion of the tail gas needs to be desulfurized and denitrified. In the existing denitrification process, NO is not easy to absorb, and needs to be further oxidized into NO₂Or N_xO_y(ii) a But even after oxidation, alkaline absorbents such as ammonia and caustic soda solutions of different concentrations are used for N_xO_yThe absorption is not ideal, which is the main reason that the current absorption tower is relatively high and the equipment is complicated. In the prior art, it has been found that NO₂And SO₂The absorption of alkali liquor is mutually promoted, but the research on the process is little.

On the other hand, the existing desulfurization and denitrification devices are built according to the current environmental protection requirements, and with the upgrading of the environmental protection requirements, particularly the implementation of ultra-low emission standards, part of the existing devices and processes cannot meet new environmental protection regulations. How to upgrade the technology rather than push it over is a very worthwhile problem to study.

Aiming at the defects of the prior art, the flue gas desulfurization and denitrification device which is economical, efficient, simple in process and small in equipment floor area and the method for realizing resource utilization of nitrogen and sulfur elements while performing desulfurization and denitrification by using the device have important significance.

Disclosure of Invention

The invention aims to provide a desulfurization and denitrification integrated synergistic absorption process and equipment. The technical scheme for specifically realizing the aim of the invention is as follows: discloses a wet absorption process for main pollutants in flue gas, namely nitric oxide or sulfide or both nitric oxide and sulfur dioxide, which realizes that NO is absorbed by using alkali liquor as an absorbent by regulating the concentration and the proportion of nitric oxide and sulfur dioxide₂And SO₂And the synergistic absorption is realized, and the exhaust emission standard is reached.

Further, the flue gas includes, but is not limited to, flue gas of a coke-oven plant, or tail gas after combustion of a boiler using coal as a main fuel in other plants; the main pollutants of the flue gas of the coke-oven plant mainly comprise nitrogen oxides and a small amount of sulfur dioxide; the main pollutants of the flue gas of other factories are mainly sulfur dioxide;

further, the wet alkaline absorbent includes, but is not limited to, ammonia water, NaOH solution, etc. with different concentrations;

further, the control nitrogen oxides mainly comprise and are not limited to NO and NO₂、N₂O₃、N₂O₄The ratio of nitrogen oxide to sulfur dioxide mainly refers to the conversion of NO by oxidation and other processes₂Or with NO₂The equivalent ratio of nitrogen oxides to sulfur dioxide is carried out. The oxidation process includes, but is not limited to, oxidizing nitric oxide with hydrogen peroxide or ozone to produce nitrogen dioxide or high-priced nitrogen oxides;

further, the ratio of nitrogen oxide to sulfur dioxide is, when NO_xConcentration x is 100<x<＝930mg/m³Control of SO₂Concentration y (mg/m)³) At y>1.7x + 209; or when NO is present_xConcentration x is 930<x<2500mg/m³Control of SO₂Concentration y (mg/m)³) At y>＝4.17x-2234；NO₂Can be absorbed by the absorbent to absorb NO in the tail gas_xTo achieve<100mg/m³A standard of (2); more preferably, when NO₂Concentration x is 100<x<＝930mg/m³Control of SO₂Concentration y (mg/m)³) At y>1.7x + 359; or when NO is present₂Concentration x is 930<x<2500mg/m³Control of SO₂Concentration y (mg/m)³) At y>＝4.17x-1934；NO₂Can be absorbed by the absorbent to absorb NO in the tail gas_xTo achieve<100mg/m³A standard of (2);

further, the ratio of nitrogen oxide to sulfur dioxide is, when NO_xConcentration x, at 50<x<2500mg/m³Control of SO₂Concentration y (mg/m)³) At y>3.78 x-229; NO in tail gas after absorption_xTo achieve<50mg/m³A standard of (2); more preferably, SO is controlled₂Concentration y (mg/m)³) At y>3.78x-129；NO₂Can be absorbed by the absorbent to absorb NO in the tail gas_xTo achieve<50mg/m³A standard of (2);

further, the ratio of the nitrogen oxide to the sulfur dioxide is determined as SO in the flue gas₂Has a concentration of y (mg/m)³) Control of NO in flue gas_xConcentration x (mg/m) of³) Having y of<4.37x-107, or x>SO in the flue gas at 0.229y + 24%₂Absorbed by the lye and totally oxidized into sulfate radicals. More preferably, NO in the flue gas is controlled₂Concentration x (mg/m) of³)，x>0.229y +44, SO in flue gas₂Absorbed by the lye and totally oxidized into sulfate radicals.

Further, the techniques for controlling the concentration ratio of nitrogen oxides or sulfur dioxide include, but are not limited to: SO-containing products obtained by combustion of sulfur pastes₂Regulating NO by flue gas, by compounding flue gases of different factories₂With SO₂Or by means of high-voltage arc discharge or the like₂To adjust the ratio between the two.

Further, under the process conditions, sulfur dioxide promotes the absorption of nitrogen dioxide and is converted into nitrate radicals; meanwhile, the absorption of the nitrogen oxide improves the oxidation rate of sulfite in the absorbent, so that sulfur dioxide can be converted into sulfate from sulfite at the initial absorption stage, and the requirement that auxiliary oxidation equipment and procedures are needed for further oxidizing the sulfite in the follow-up process is met.

According to the invention to realize NO₂-SO₂The integrated equipment for cooperative absorption is characterized by comprising a feeding device, an absorption device and a gas-liquid separation device, wherein the feeding device is communicated with the absorption device, and the absorption device is communicated with the gas-liquid separation device; in the absorption device, NO₂-SO₂Mixed with absorbent to react and be absorbed and removed.

Further, it is characterized in that: the absorption device is an absorption tower or a micro-reactor.

Further, the absorption means is preferably a microreactor; more preferably a microdispersion reactor; the micro-dispersion reactor comprises a dispersed phase module, a continuous phase module and a dispersion medium;

further, it is characterized in that: the feeding device comprises a gas feeding device and a liquid feeding device.

Further, the microreactor is free of NO₂-SO₂The gas is a dispersed phase, and NO is added into the dispersion medium in the microreactor₂-SO₂The gas is dispersed as tiny droplets of 10-200 microns and dispersed in the absorbent in the continuous phase. Compared with the traditional absorption tower absorption method, the micro-reactor has smaller dispersed liquid drops, improved surface area and capability of rapidly absorbing NO₂-SO₂The gas is dispersed in the absorbent and removed by means of reaction, thereby improving the absorption efficiency.

Further, the dispersion medium employed in the microdispersion-type reactor includes, but is not limited to, a flat plate-like, tubular-type dispersion medium; further, the dispersion medium is characterized in that: the dispersion medium is positioned between the dispersed phase module and the continuous phase module and is a microporous membrane, a microfiltration membrane or a micro-sieve pore membrane and the like. The pore size of the dispersion medium is 0.2 to 100um, preferably 0.2 to 20um, more preferably 0.1 to 5 um.

Compared with the prior art, the integrated process and equipment for synergistic absorption of desulfurization and denitrification provided by the invention have the following advantages: absorption efficiency is high, and equipment is simple, and the input cost is low, can realize nitrogen sulfur element resource utilization when reducing the pollution, specifically as follows:

firstly, the component proportion of nitrogen oxide and sulfur dioxide in the flue gas is controlled, so that the nitrogen dioxide and the sulfur dioxide are absorbed cooperatively, the absorption rate of the nitrogen oxide is improved, necessary oxidation procedures in the traditional desulfurization equipment are reduced, and the resource utilization of high-efficiency nitrogen elements and sulfur elements is realized; secondly, the dispersion phase (NO) is brought about by means of an efficient absorption device, in particular a preferred microdispersion reactor₂-SO₂) The micro-bubble is mixed with the continuous phase in the micro-reactor in the form of micron-sized bubbles, so that the mass transfer surface area is increased, the mass transfer efficiency is improved, the reaction can be carried out under the condition of almost NO mass transfer limitation, the reaction efficiency is improved, and NO is increased₂-SO₂Gas absorption rate; thirdly, the optimized micro-reactor equipment is used, the size is small, gas-liquid mixing is realized by taking the pressure difference of two phases as a driving force, the equipment is simple, and the investment cost of the whole absorption device is reduced; fourthly, when ammonia water is used as an absorbent, SO is absorbed₂Meanwhile, an ammonium sulfite solution can be generated, and the ammonium sulfite solution can efficiently absorb NO₂Meanwhile, unstable ammonium sulfite is oxidized into ammonium sulfate, thereby further promoting SO of the absorbent ammonia water₂The absorption of the ammonium sulfate and the ammonium nitrate is promoted by mutual protection, the absorption product is a mixed byproduct of the ammonium sulfate and the ammonium nitrate, the nitrogen content of the mixed byproduct is higher than that of the pure ammonium sulfate, and the mixed byproduct can be used as a chemical fertilizer to realize resource utilization of nitrogen and sulfur elements. Fifthly, for the traditional coking plant, the content of NO in the flue gas is high, and SO is high₂Low in content, and can be oxidized into NO by hydrogen peroxide process or ozone oxidation process₂SO is obtained by burning the sulfur paste which is the by-product inside the coke-oven plant₂And the two components are absorbed cooperatively, so that the resource treatment of the solid sulfur paste which is difficult to treat and the NOx in the flue gas is realized. Sixth, existing equipment can be modified appropriately to meet increasingly stringent emission standards, such as ultra-low emission standards, in accordance with the process of the present invention. The existing desulfurization and denitrification operation equipment is based on the early-stage emission standard, such as NO_xDischarge 200mg/m³Up to, or 150mg/m³Designing in the interior; however, with the increasing environmental requirements, partial area of NO_xThe emission needs to meet ultra-low emission standards: NO_xThe emission is 100mg/m³May even be required to be within 80mg/m³Or even 50mg/m³Within. The existing process can not meet the requirements of the desulfurization and denitrification device any more; according to the process requirements of the invention, the proportion of the fed nitrogen oxide and the sulfur dioxide is properly adjusted, and the existing desulfurization and denitrification device is combined to meet higher emission standards; this greatly reduces the cost of the replicated construction.

Drawings

FIG. 1 is a schematic diagram of an integrated equipment system for desulfurization and denitrification in coordination with absorption.

FIG. 2 is a graph of the fit of examples 1-4.

Detailed Description

In the drawings, the components represented by the respective reference numerals are listed below:

FIG. 1 is a schematic diagram of a desulfurization and denitrification synergistic absorption integrated equipment system, wherein the components represented by the reference numerals are as follows: 1. the system comprises a feeding device, 4, a first mass flow meter, 5, a second mass flow meter, 6, a third mass flow meter, 7, a first gas supply device, 8, a second gas supply device, 9, an air compressor, 10, a advection pump, 11 and an absorbent storage tank; 2. the device comprises an absorption device, a 12 micro-reactor, a 3 gas-liquid separation device and a 13 gas-liquid separation tank.

In order that those skilled in the art will better understand the present invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings and its implementation method.

The present invention is described in further detail below with reference to examples, which should be construed as merely illustrative and not a limitation of the scope of the present invention. Furthermore, it should be understood that various changes or modifications of the present invention and further its application to the synthesis of similar other sulfonate compounds may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents are intended to fall within the scope of the appended claims.

The invention provides integrated equipment for desulfurization and denitrification synergistic absorption, which is used for treating waste gas, wherein the waste gas comprises flue gas of a coke-oven plant or tail gas after combustion of a boiler using coal as a main fuel in other plants; the main pollutants of the flue gas of the coke-oven plant mainly comprise nitrogen oxides and a small amount of sulfur dioxide; the main pollutants of the flue gas of other factories are sulfur dioxide.

Wherein the nitrogen oxides mainly comprise and are not limited to NO and NO₂、N₂O₃、N₂O₄The ratio of nitrogen oxide to sulfur dioxide mainly refers to the conversion of NO by oxidation and other processes₂Or with NO₂The equivalent ratio of nitrogen oxides to sulfur dioxide is carried out. The oxidation process includes, but is not limited to, oxidation of nitric oxide with hydrogen peroxide or ozone to produce nitrogen dioxide or higher nitrogen oxides.

The equipment comprises a feeding device 1, an absorption device 2 and a gas-liquid separation device 3, wherein the feeding device 1 is communicated with the absorption device 2, and the absorption device 2 is communicated with the gas-liquid separation device 3.

Wherein the feeding device comprises a first gas supply device 7 and a second gas supply device 8 for supplying SO₂、NO₂The device comprises a gas, an air compressor 9 for providing compressed waste gas, an absorbent providing device 11 for providing absorbent, a constant flow pump 10 for conveying the absorbent, and a first mass flow meter 4, a second mass flow meter 5 and a third mass flow meter 6 which are arranged on a pipeline and are respectively used for controlling SO₂、NO₂The amount of gas and exhaust gas provided.

The absorption device 2 comprises a first-stage microreactor comprising a first inlet communicating with the first gas supply means 7, the second gas supply means 8 and the air compressor 9 via conduits and a second inlet communicating with the absorbent supply means 11 via conduits. SO provided by the first gas supply device 7, the second gas supply device 8 and the air compressor 9₂、NO₂The gas and the exhaust gas are mixed with the absorbent supplied from the absorbent supply means 11 in the absorption means 2 to form a reaction liquid. The outlet of the absorption device 2 is separated from gas and liquidThe separation tank 13 is communicated, and after the reaction liquid is subjected to gas-liquid separation in the gas-liquid separation tank 13, the gas is discharged through a gas outlet of the gas-liquid separation tank 10.

Wherein, the absorbent is an alkaline absorbent, and comprises ammonia water with different concentrations, NaOH solution and the like.

In one aspect, the first gas providing device is a gas storage tank; the second gas supply device is a gas storage tank or a high-voltage arc discharge device or a combination thereof.

In one aspect, the first gas providing device and the second gas providing device respectively provide one of the gases SO2 and NO2, or the first gas providing device and the second gas providing device both provide flue gas containing different contents of SO2 and NO 2.

In one embodiment, the absorption device 2 is an absorption tower or a microreactor. And, preferably, said absorption means is a microreactor; more preferably a microdispersion reactor; the micro-dispersion reactor comprises a dispersed phase module, a continuous phase module and a dispersion medium;

preferably, the microreactor is free of NO₂-SO₂The gas is a dispersed phase, and NO is added into the dispersion medium in the microreactor₂-SO₂The gas is dispersed as tiny droplets of 10-200 microns and dispersed in the absorbent in the continuous phase. Compared with the traditional absorption tower absorption method, the micro-reactor has smaller dispersed liquid drops, improved surface area and capability of rapidly absorbing NO₂-SO₂The gas is dispersed in the absorbent and removed by means of reaction, thereby improving the absorption efficiency.

Further, the dispersion medium employed in the microdispersion-type reactor includes, but is not limited to, a flat plate-like, tubular-type dispersion medium; further, the dispersion medium is characterized in that: the dispersion medium is positioned between the dispersed phase module and the continuous phase module and is a microporous membrane, a microfiltration membrane or a micro-sieve pore membrane and the like. The pore size of the dispersion medium is 0.2 to 100um, preferably 0.2 to 20um, more preferably 0.1 to 5 um.

Nitrogen dioxide and sulfur dioxide are absorbed cooperatively by controlling the component proportion of nitrogen oxide and sulfur dioxide in the flue gas, the sulfur dioxide is converted into sulfite after being absorbed, the existence of the sulfite improves the absorption rate of the nitrogen oxide, and the nitrogen oxide is converted into nitrate radical; meanwhile, the absorption of the nitrogen oxide improves the oxidation rate of sulfite in the absorbent, sulfur dioxide can be converted into sulfate from sulfite at the initial stage of absorption, necessary oxidation procedures in the traditional desulfurization equipment are reduced, and the resource utilization of nitrogen and sulfur elements is realized efficiently.

The invention also provides a desulfurization and denitrification synergistic absorption method, which is realized by the equipment and comprises the following steps:

the waste gas and sulfur dioxide SO₂Nitrogen dioxide NO₂The absorbent is introduced into the absorption device 2;

detection of nitrogen oxides NO in an absorption device_xAnd sulfur dioxide SO₂The content of (A);

according to nitrogen oxides NO in the absorption device_xAnd sulfur dioxide SO₂At least one of the first flowmeter 4, the second flowmeter 5 and the third flowmeter 6 is controlled to further adjust the sulfur dioxide SO₂Nitrogen dioxide NO₂The supply of waste gas to make the absorption device 2 sulfur dioxide SO₂With nitrogen oxides NO_xThe content of (b) satisfies a certain relationship.

In one embodiment, the content of nitrogen oxide and sulfur dioxide is related to that of nitrogen oxide NO_xConcentration x, at 50<x<2500mg/m³Control of SO₂Concentration y (mg/m)³) At y>3.78 x-229; the scheme is adopted to absorb NO in the tail gas_xTo achieve<50mg/m³A standard of (2); more preferably, SO is controlled₂Concentration y (mg/m)³) At y>3.78x-129；NO₂Can be absorbed by the absorbent to absorb the nitrogen oxide NO in the tail gas_xTo achieve<50mg/m³The standard of (2).

In one embodiment, the nitrogen oxide and sulfur dioxide content relationship is when nitrogen oxide NO_xConcentration x is 100<x<＝930mg/m³Control of sulfur dioxide SO₂Concentration y (mg/m)³) At y>1.7x + 209; or when being nitridedSubstance NO_xConcentration x is 930<x<2500mg/m³Control of sulfur dioxide SO₂Concentration y (mg/m)³) At y>＝4.17x-2234；NO₂Can be absorbed by the absorbent to absorb the nitrogen oxide NO in the tail gas_xTo achieve<100mg/m³A standard of (2); more preferably, when nitrogen oxides NO_xConcentration x is 100<x<＝930mg/m³Control of sulfur dioxide SO₂Concentration y (mg/m)³) At y>1.7x + 359; or when the concentration x of nitrogen oxides NOx is 930<x<2500mg/m³Control of sulfur dioxide SO₂Concentration y (mg/m)³) At y>4.17 x-1934; nitrogen oxides NO_xCan be absorbed by the absorbent to absorb the nitrogen oxide NO in the tail gas_xTo achieve<100mg/m³A standard of (2);

in one scheme, when sulfur dioxide SO is in the flue gas₂Has a concentration of y (mg/m)³) Control of nitrogen oxides NO in flue gas_xConcentration x (mg/m) of³) So that y is<4.37x-107, or x>0.229y + 24. By adopting the scheme, SO in the flue gas₂Absorbed by alkali liquor and oxidized into sulfate radical. More preferably, NO in the flue gas is controlled₂Concentration x (mg/m) of³) Is x>0.229y + 44. At this time, SO in the flue gas₂Absorbed by the lye and totally oxidized into sulfate radicals.

In an alternative, the ratio between NO2 and SO2 may be adjusted by using a flue gas compound ratio of NO2 and SO2 content, i.e. the first gas providing device 7 and the second gas providing device provide flue gas containing NO2 and SO2 content, respectively.

In another alternative, a high voltage arc discharge device is provided to generate NO by electrical discharge or the like₂To adjust the ratio between the two. In one aspect, a high voltage arc discharge device is combined with the gas supply device.

In one embodiment, the method further comprises the step of predetermining the ratio of nitrogen oxides to sulfur dioxide, wherein the step is implemented by using the above equipment, and the step comprises the following steps:

the waste gas and sulfur dioxide SO₂Nitrogen dioxide NO₂All the absorbent is throughEntering an absorption device 2;

real-time detection of nitrogen oxide NO in mixed gas at outlet of absorption device 2_xAnd sulfur dioxide SO₂The content of (A);

adding NO₂And SO₂Is fixed to a predetermined value, and NO is adjusted by adjusting the first mass flow meter 4 or the second mass flow meter 5₂And SO₂The value of the content of the other.

When detecting the nitrogen oxide NO in the mixed gas at the outlet of the absorption device 2_xAnd sulfur dioxide SO₂When the content of (D) is less than a predetermined value, recording NO₂And SO₂The value of the content of the other;

repeating the above process for multiple times, and recording multiple groups of NO₂And SO₂A predetermined value of one of and NO₂And SO₂The other one is then plotted to obtain a curve of the relationship between the two.

The procedure for predetermining the ratio of nitrogen oxides to sulfur dioxide according to the invention is described below in connection with specific examples 1 to 4.

Example 1

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, mixed gas with different proportions and contents is obtained by adjusting mass flow meters in respective gas circuits, the mixed gas is introduced into a dispersed phase inlet of the microreactor, the total flow is 1.0L/min, and NO in the mixed gas at the outlet of the microreactor is measured by a smoke meter₂、SO₂、O₂After the content is reached, 5 percent NaOH solution is introduced into a continuous phase inlet of the microreactor, the flow rate is 10ml/min, and SO is respectively added₂At 550-7000mg/m³(200ppm-2500ppm) fixed at one point and then gradually increasing NO₂Content, gas absorption at room temperature, recorded to meet NOx < 100mg/m³，NO₂At maximum content, NO₂And SO₂The contents are respectively corresponding to the data and are recorded as (NO)₂,SO₂) A series of points were obtained which met the conditions, the data are shown in Table 1, plotted in FIG. 2, and labeled "NOx over-regulation 100r data" and "NOx over-regulation 100r2 data".

When NO is present_xInitial concentration 250<x<＝930mg/m³Fitting to obtain SO₂Concentration y (mg/m)³)：y＝1.70x+209,R²0.978, labeled "NOx-100 curve 1 b" in fig. 2; when NO is present_xInitial concentration x>930mg/m³Fitting to obtain SO₂Concentration y (mg/m)³)：y＝4.17x-2234,R²0.983, as in fig. 2, with "NOx-100 curve 1 a", i.e. for NO_xInitial concentration x, when SO in the system₂When the concentration is higher than the upper value of the curve 1, the NOx emission concentration after absorption meets 100mg/m³And (4) requiring.

Example 2

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, mixed gas with different proportions and contents is obtained by adjusting mass flow meters in respective gas circuits, the mixed gas is introduced into a dispersed phase inlet of the microreactor, the total flow is 1.0L/min, and NO in the mixed gas at the outlet of the microreactor is measured by a smoke meter₂、SO₂、O₂After the content is reached, 5 percent NaOH solution is introduced into a continuous phase inlet of the microreactor, the flow rate is 10ml/min, and SO is respectively added₂At 550-7000mg/m³(200ppm-2500ppm) fixed at one point and then gradually increasing NO₂Content, gas absorption at room temperature, recorded to satisfy NO_x＜50mg/m³，NO₂At maximum content, NO₂And SO₂The contents are respectively corresponding to the data and are recorded as (NO)₂,SO₂) A series of points were obtained which met the conditions, the data is shown in Table 1, plotted in FIG. 2, and labeled "NOx over-Standard 50 data".

When initial concentration x of NOx>200mg/m³Time fitting to obtain SO₂Concentration y (mg/m)³):y＝3.783x-229,R²0.992, labeled "NOx-50 curve 2" in fig. 2; that is to NO_xInitial concentration x, when SO in the system₂NO after absorption at concentrations above the upper value of curve 2_xThe discharge concentration meets 50mg/m³And (4) requiring.

Example 3

The air compressor is turned on and respectivelyWill contain a certain concentration of NO₂、SO₂The standard gas cylinder is opened, mixed gas with different proportions and contents is obtained by adjusting mass flow meters in respective gas circuits, the mixed gas is introduced into a dispersed phase inlet of the microreactor, the total flow is 1.0L/min, and NO in the mixed gas at the outlet of the microreactor is measured by a smoke meter₂、SO₂、O₂After the content is reached, 5 percent NaOH solution is introduced into a continuous phase inlet of the microreactor, the flow rate is 10ml/min, and NO is respectively added₂At 250 ℃ 2260mg/m³(120ppm-1100ppm) and then gradually increasing SO₂Content, gas absorption at room temperature, recorded to satisfy NO_x＝0mg/m³，SO₂At the smallest content, NO₂And SO₂The contents are respectively corresponding to the data and are recorded as (NO)₂,SO₂) A series of points were obtained which satisfied the conditions, the data are shown in table 1, plotted in figure 2, and labeled "NOx complete absorption data".

When NO is present_xInitial concentration x>200mg/m³Fitting to obtain SO₂Concentration y (mg/m)³) When y is 4.28x-178, R²0.993, labeled "NOx complete absorption curve 3" as in fig. 2.

That is when SO is present₂SO at concentrations above curve 3₂,NO₂Are absorbed by the absorption liquid.

Example 4 the air compressor was turned on and the respective solutions were mixed to contain a certain concentration of NO₂、SO₂The standard gas cylinder is opened, mixed gas with different proportions and contents is obtained by adjusting mass flow meters in respective gas circuits, the mixed gas is introduced into a dispersed phase inlet of the microreactor, the total flow is 1.0L/min, and NO in the mixed gas at the outlet of the microreactor is measured by a smoke meter₂、SO₂、O₂After the content is reached, 5 percent NaOH solution is introduced into a continuous phase inlet of the microreactor, the flow rate is 10ml/min, and NO is respectively added₂At 250 ℃ 2260mg/m³(120ppm-1100ppm) and then gradually increasing SO₂Content, gas absorption at room temperature, recorded to meet SO₃ ^2-Is 0, SO₂At maximum content, NO₂And SO₂Data corresponding to the contents recorded as(NO₂,SO₂) A series of points satisfying the conditions were obtained, the data are shown in Table 1, plotted in FIG. 2, and labeled "SO 32-occurrence data".

When SO₂Concentration y (mg/m)³) Fitting to obtain NO_xInitial concentration x (mg/m)³) When y is 4.37x-107, or x is 0.229y +24, R is²Fig. 2 with 0.996 indicates "SO 32" appearance curve 4 ", i.e. when NO_xWhen the concentration is higher than the curve 4, the sulfite in the absorption liquid is completely converted into sulfate. By means of NO₂Synergistic absorption to solve SO₂The problem of further oxidation after absorption, direct addition of SO₃ ^2-By oxidation to SO₄ ^2-。

Table 1 example data

Example 5

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂Has a content of 900mg/m³，SO₂The content of (b) is 1750mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 1mg/m³，NO_xThe content is 87mg/m³Satisfying NOx < 100mg/m³The emission standard of (1). (in accordance with the range of NO_xInitial concentration 900, i.e. 250<x<＝930mg/m³When actually inputting SO₂Concentration y 1-1750 (mg/m)³): curve a1, y 1.70x +209 1739 (mg/m) meeting the 100 emission requirement line³)。y1>y, the operating point is located in the upper left space of the curve a1, thus meeting the emission standard of 100. )

Example 6

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂Has a content of 960mg/m³，SO₂Has a content of 3520mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 0mg/m³，NO_xThe content is 23mg/m³Satisfying NOx less than 50mg/m³The emission standard of (1). (NO)_xInitial concentration x 960mg/m³Then, actual SO₂Concentration y1 ═ 3520mg/m³: curve 2 is defined according to 50 emission standards, y 3.783x-229 3403; y1>y. The operating point is located in the upper left space of curve 2 and therefore meets the emission standard of 50. )

Example 7

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂Has a content of 1350mg/m³，SO₂Has a content of 5650mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 0mg/m³，NO_xThe content is 1mg/m³At this time, NO is contained in the gas₂、SO₂Are all absorbed by the absorption liquid. (NO)_xInitial concentration x 1350mg/m³Then, actual SO₂Concentration 5650mg/m³Complete absorption curve 3, y is 4.28x-178 is 5600; y1>y. The operating point is located in the upper left space of curve 3 and therefore the full absorption condition is met. )

Example 8

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂The content of (B) is 1571mg/m³，SO₂The content of (A) is 6650mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 0mg/m³，NO_xThe content is 3mg/m³At this time, NO is contained in the gas₂、SO₂Are all absorbed by the absorption liquid, and simultaneously, the components of the absorption liquid are titrated and analyzed, and the absorption liquid does not contain SO₃ ^2-By oxidation to SO₄ ^2-I.e. all SO₃ ^2-Are all oxidized into SO₄ ^2-。(NO_xInitial concentration x 1571mg/m³Then, actual SO₂Concentration 6650mg/m³Complete absorption curve and limit curve for appearance of sulfite 4: y-4.37 x-107-6758, y1<y. The operating point is located in the lower right space of curve 4, so that the complete absorption conditions are met and no sulphite is present. )

Example 9

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂Has a content of 960mg/m³，SO₂Is 3120mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 0mg/m³，NO_xThe content is 65mg/m³Data points between curve 2 and curve 1a fail to satisfy NOx < 50mg/m³The emission standard of (c); but satisfies NOx < 100mg/m³The emission standard of (1).

Comparative example 1 (NOx < 100mg/m³Emission standard of (2)

The air compressor is turned on and will contain one respectivelyConstant concentration of NO₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.0L/min₂Has a content of 900mg/m³，SO₂The content of (A) is 1400mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 1mg/m³，NO_xThe content is 125mg/m³Data points below curves 1a and 1b fail to satisfy NOx < 100mg/m³The emission standard of (1).

Comparative example 2

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂、SO₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.3L/min₂Has a content of 225mg/m³，SO₂Is 0mg/m³Introducing 5% NaOH solution into the continuous phase inlet of the microreactor at the flow rate of 10ml/min, performing gas absorption at room temperature, and measuring SO in the absorbed gas₂Is 10mg/m³，NO_xThe content is 160mg/m³Data points outside curves 1a and 1b fail to satisfy NOx < 100mg/m³The emission standard of (1).

Comparative example 3

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂The standard gas cylinder is opened, and NO is sprayed by using a spray tower through adjusting mass flowmeters in respective gas paths₂Absorbing with 10% NaOH as spraying liquid and NO as raw material gas inlet₂The content of (B) is 250mg/m³，SO₂Is 10mg/m³The oxygen content is 10 percent, the gas flow is 1L/min, 10 percent NaOH solution with the flow of 10ml/min is absorbed at room temperature, and the SO in the absorbed gas is measured₂Is 1mg/m³，NO_xThe content is 170mg/m³Data points outside curves 1a and 1b fail to satisfy NOx < 100mg/m³The emission standard of (1).

Comparative example 4

The air compressor is turned on, and the gas respectively contains NO with a certain concentration₂The standard gas cylinder is opened, and the mass flow meters in respective gas circuits are adjusted to ensure that the total flow of NO in the mixed gas introduced into the dispersed phase inlet of the microreactor is 1.3L/min₂Has a content of 225mg/m³Oxygen content 10% in 50mL of 6% Na₂SO₃And (3) introducing the solution into a continuous phase inlet of the microreactor, wherein the flow is 10ml/min, circulating the continuous phase, and performing gas absorption at room temperature until NOx at an outlet exceeds the standard. Measuring NO in the absorbed gas after 80min_xThe content is 150mg/m³Cannot satisfy NOx < 150mg/m³The emission standard of (1). Na used during reaching the emission standard₂SO₃The number of moles being NO₂50 times of the theoretical molar ratio of the reaction, i.e. the actual amount is 25 times the theoretical amount, is 2: 1. The main reason is that sulfite is unstable, and part of sulfite is used as a reactant for absorbing NOx and reacts with oxygen in the flue gas, so that a large amount of sulfite is consumed. Comparison of SO of the invention₂With NO₂Synergistic absorption, under the condition of complete absorption, the molar ratio of the two is about 3:1, which is 1.5 times of the theoretical dosage; if NOx is satisfied<150mg/m³In the case of (3), SO₂The amount used was lower, about 1 to 1.4 times the theoretical amount (cf. comparative example 1). The process of the present invention has significant advantages over the use of sulfite oxidation absorption.

As can be seen from the above examples and comparative examples, the NO in intake air is adjusted by the law obtained by the present invention₂、SO₂The content of (a) can meet the requirement that the outlet NOx is less than 50mg/m³、100mg/m³、150mg/m³And all SO in the absorption liquid₃ ^2-Are all oxidized into SO₄ ^2-And the like.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims (10)

1. The utility model provides a desulfurization denitrogenation is absorbed integration equipment in coordination which characterized in that: the equipment comprises a feeding device, an absorption device and a gas-liquid separation device, wherein the feeding device is communicated with the absorption device, the absorption device is communicated with the gas-liquid separation device, and the feeding device comprises a first gas supply device and a second gas supply device and is used for supplying SO₂、NO₂The device also comprises a first mass flow meter, a second mass flow meter and a third mass flow meter which are arranged on the pipeline and are respectively used for controlling SO₂、NO₂Gas and exhaust gas.

2. The integrated equipment for desulfurization, denitrification and cooperative absorption according to claim 1, wherein: the first gas supply device is a gas storage tank; the second gas supply device is a gas storage tank or a high-voltage arc discharge device or a combination thereof.

3. The integrated equipment for desulfurization, denitrification and cooperative absorption according to claim 1, wherein: the first gas supply device and the second gas supply device respectively supply SO₂、NO₂One kind of gas species, or

The first gas supply device and the second gas supply device both supply SO containing different contents₂、NO₂The flue gas of (1).

4. The integrated equipment for desulfurization, denitrification and cooperative absorption according to claim 1, wherein: the absorption device comprises a first-stage microreactor which comprises a first inlet and a second inlet, wherein the first inlet is communicated with a first gas supply device, a second gas supply device and an air compressor through pipelines, and the second inlet is communicated with the first gas supply device, the second gas supply device and the air compressor through pipelinesThe pipeline is communicated with an absorbent providing device, the first gas providing device, the second gas providing device and SO provided by the air compressor₂、NO₂The gas and the waste gas are mixed with the absorbent provided by the absorbent providing device in the absorption device to form reaction liquid, an outlet of the absorption device is communicated with the gas-liquid separation device, and the gas is discharged through the exhaust port after the reaction liquid is subjected to gas-liquid separation in the gas-liquid separation device.

5. The integrated equipment for desulfurization, denitrification and cooperative absorption according to claim 1, wherein: the absorption device is an absorption tower or a micro-reactor.

6. A desulfurization and denitrification synergistic absorption method is characterized by comprising the following steps: the method is implemented by the apparatus of any one of claims 1-5, the method comprising:

the waste gas and sulfur dioxide SO₂Nitrogen dioxide NO₂The absorbent is introduced into the absorption device;

detection of nitrogen oxides NO in an absorption device_xAnd sulfur dioxide SO₂The content of (A);

according to nitrogen oxides NO in the absorption device_xAnd sulfur dioxide SO₂At least one of the first flow meter, the second flow meter and the third flow meter is controlled to further adjust the sulfur dioxide SO₂Nitrogen dioxide NO₂The supply of waste gas to make the absorption device sulfur dioxide SO₂With nitrogen oxides NO_xThe content of (b) satisfies a certain relationship.

7. The desulfurization and denitrification synergistic absorption method according to claim 6, wherein: the method comprises the following steps: when nitrogen oxide NO_xConcentration x, at 50<x<2500mg/m³Control of SO₂Concentration y (mg/m)³) At y>3.78 x-229; NO in tail gas after absorption_xTo achieve<50mg/m³A standard of (2); .

8. According to the rightThe method for synergistic absorption of desulfurization and denitrification according to claim 7, characterized in that: controlling SO₂Concentration y (mg/m)³) At y>3.78x-129, NO in tail gas after absorption_xTo achieve<50mg/m³The standard of (2).

9. The desulfurization and denitrification synergistic absorption method according to claim 6, wherein: the content of nitrogen oxide and sulfur dioxide is related when NO is_xConcentration x is 100<x<＝930mg/m³Control of SO₂Concentration y (mg/m)³) At y>1.7x + 209; or the content of nitrogen oxide and sulfur dioxide is related when NO is_xConcentration x at x>930mg/m³Control of SO₂Concentration y (mg/m)³) At y>4.17 x-2234; NO in tail gas after absorption_xTo achieve<100mg/m³The standard of (2).

10. The desulfurization and denitrification synergistic absorption method according to claim 6, wherein: the content relationship of the nitrogen oxide and the sulfur dioxide is that when the concentration of the sulfur dioxide is y (mg/m)³) Controlling the concentration x (mg/m) of nitrogen oxides³) So that y is<4.37x-107, or x>0.229y + 24; . SO in flue gas₂Absorbed by the lye and totally oxidized into sulfate radicals.

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