CN101053748A - Simultaneously removing various pollutant wet ammonia flue gas cleaning technology and system thereof - Google Patents

Abstract

A wet ammonium flue gas cleaning process for depriving multipollutant and a system thereof are disclosed. The process firstly oxidates NO in the flue gas to be NO2, makes SO2 and NO2 in the flue gas react with ammonium to product ammonium sulfite, ammonium nitrate and ammonium nitrite, then oxidates ammonium sulfite and ammonium nitrite therein to product the byproduct that is ammiaonia sulfate and ammonium nitrate, performs an electrodedust treatment to deprive SO3 and ammonium aerosol in the flue gas to obtain clear flue gas. The system comprises a dust pre-collector, a hydrogen peroxide or ozone sprayer, and a reaction absorber, which are connected in turns, wherein ammonia replenishment system and an air feeding device are mounted at the bottom of the reaction absorber, sprinkling layer which can cycle sprinkle is mounted at the middle, and an electrostatic precipitator is mounted at the upper. The invention can effectively raise the efficiency of dust separation, desulfurization and denitration, and also capture SO3 and NH3 aerosol escaping. At the same time, the invention has a simple process, a simplified system, a low investment and operation cost.

Description

Remove the wet ammonia flue gas cleaning technology and the system thereof of multiple pollutant simultaneously

Technical field

The present invention relates to purification treatment technology, refer to a kind of wet ammonia flue gas cleaning technology and system thereof that removes multiple pollutant simultaneously particularly flue gas that coal fired power plant discharges.

Background technology

Acid rain problem is one of global environmental problem of face of mankind nowadays, the coal-fired oxysulfide SO that produces _xWith nitrogen oxide NO _xPollution is the main protozoa of China's acid rain.Because the energy resource structure of China is based on coal, in China's power industry, thermoelectricity accounts for about 70% of gross generation always, and coal-fired power plant is the first pollution sources of China's atmosphere pollution.Power-plant flue gas polluted to control be the requirement that realizes economic, society, harmonious development, also be performance coal in China reserves advantage, realize the requirement of coal-burning power plant self sustainable development.

At present, be used for the flue gases purification of coal fired power plant,, form independently technical equipment and technological process separately as the still exploitation separately of great majority such as flue gas desulfurization, denitration and dedusting technology.The oxysulfide SO in the flue gas removes in order to reach the environment protection emission requirement in the coal-burning power plant both at home and abroad _x, nitrogen oxide NO _xAnd dust, the coal-burning power plant needs to adopt independently desulfurization more than two covers, denitration and dust pelletizing system at least.

For gas denitrifying technology, traditional method mainly contains selective catalytic reduction (SCR) and SNCR method (SNCR), though the SCR method can realize very high denitration efficiency, satisfy strict standard limit of smog release, but its technology and device systems complexity, and need special catalyst, the whole system investment is higher with operating cost.Though SNCR method technology and device systems are simple, investment and operating cost are lower, and its denitration efficiency is not high, is difficult to reach the requirement of discharging standards sometimes.

For flue gas desulfurization technique, traditional method mainly contains lime stone-gypsum method, sea water desulfuration method, recirculating fluidized bed dry type flue gas desulfurizing method and wet ammonia method for flue gas desulfurizing method or the like.Lime stone-gypsum method and sea water desulfuration method exist that floor space is big, system complex, energy consumption and the high defective of operating cost.Though recirculating fluidized bed dry type flue gas desulfurizing method system is simple, floor space is little, operating cost is low, its quality requirement to desulfurizing agent is higher, and the desulfuration byproduct calcium sulfite is difficult to comprehensive utilization.The desulfurizing tower that the wet ammonia method for flue gas desulfurizing method is adopted mainly contain packed tower, liquid column tower and spray column several, though have that floor space is little, an investment and operating cost is low, desulfuration byproduct is the advantage of valuable chemical raw material and crops chemical fertilizer, its denitration efficiency is very low.

In order to address the above problem, notification number is that the Chinese utility model patent specification of CN2712446Y and CN2746971Y has proposed a kind of " flue gas desulfurization and denitrification device " and " Desulfurization and Denitration Integrated Flue Gas Purification Tower " respectively, but its desulphurization denitration equipment is the filler device of volume bulkiness, and directly adopts ammonia spirit to absorb nitrogen oxide NO in the flue gas _x, the resistance of whole desulphurization denitration equipment is significantly increased, nor can remove the NO in the flue gas effectively _xThis is because NO _xBe nitric oxide NO more than 90% in the component, and NO is very difficult water-soluble, adopts simple washing method to be difficult to NO is absorbed.

In traditional wet ammonia method for flue gas desulfurizing method, spray column also is the desulfurizing tower of using always.Above spray column or the rear operated by rotary motion demister of deflection plate or eddy flow plate structure is arranged, but the demister of this structure just removes the drop in the flue gas, can not effectively remove in the flue gas remaining nano level SO ₃And NH ₃Aerosol.Introduced a kind of novel " demister of ammonia process of desulfurization tower " though notification number is the Chinese utility model patent specification of CN2746973Y, what this demister still adopted is filling-material structure, and its packing layer has not only strengthened the flow resistance of flue gas, and to SO ₃And NH ₃The removal effect of particulate is very little.

This shows, adopt independently desulfurization and not only flue gas purifying equipment complexity, floor space big, construction and operating cost height of denitrating system more than two covers, and these independently desulfurization, denitration and dust pelletizing system reasonable combination are got up to realize that comprehensive high-efficiency moves also many difficulties.

Summary of the invention

Purpose of the present invention is exactly that a kind of wet ammonia flue gas cleaning technology and system thereof that removes multiple pollutant simultaneously will be provided.Adopt this technology and system thereof can effectively improve dedusting, desulfurization and the denitration efficiency of flue gas, and can effectively catch the SO of escape ₃And NH ₃Aerosol.Its technological process simultaneously is simple, system architecture simplification, investment and operating cost are cheap, but to handle byproduct be the ammonium sulfate and the ammonium nitrate fertilizer of recycling to flue gas.

For achieving the above object, removing the wet ammonia flue gas cleaning technology of multiple pollutant when the present invention is designed, is after the flue gas that needs desulfurization is carried out pre-dust removal process, to handle by following processing step again:

1) adopts oxydol H ₂O ₂Or ozone O ₃As oxidant,, as atomizing medium it evenly is ejected into through in the flue gas of pre-dust removal process with air, make in the flue gas nitric oxide NO both with hydrogen peroxide or ozone generation chemical reaction, also with airborne oxygen generation chemical reaction, generate nitrogen dioxide NO ₂Gas.The equation of its chemical reaction is as follows:

NO+H ₂O ₂=NO ₂+ H ₂O or NO+O ₃=NO ₂+ O ₂

2NO+O ₂＝2NO ₂

So just the nitric oxide NO with the overwhelming majority in the flue gas is oxidized into nitrogen dioxide NO ₂, for the denitration efficiency that improves flue gas is laid a solid foundation.But simultaneously also can be with part sulfur dioxide SO ₂Be oxidized into sulfur trioxide SO ₃, the sulfur trioxide SO that is generated ₃Can in follow-up dust collecting process, eliminate.The equation of its chemical reaction is as follows:

SO ₂+ H ₂O ₂=SO ₃+ H ₂O or SO ₂+ O ₃=SO ₃+ O ₂

2SO ₂+O ₂＝2SO ₃

2) adopt ammoniacal liquor NH ₃As desulfurization denitrification agent, it is ejected into through in the flue gas of oxidation processes, make sulfur in smoke SO ₂With nitrogen dioxide NO ₂With ammoniacal liquor generation chemical reaction, generate ammonium sulfite (NH respectively ₄) ₂SO ₃, ammonium nitrate NH ₄NO ₃With ammonium nilrite NH ₄NO ₂Mixture.Can adopt mass percentage concentration is 25～30% ammoniacal liquor and sulfur dioxide SO ₂With nitrogen dioxide NO ₂Carry out the gas-liquid two-phase reaction.The equation of its chemical reaction is as follows:

2NH ₃+SO ₂+H ₂O＝(NH ₄) ₂SO ₃

2NH ₃+2NO ₂+H ₂O＝NH ₄NO ₂+NH ₄NO ₃

3) adopt air as oxidant, it is ejected into the ammonium sulfite (NH that desulfurization and denitrification reaction generates ₄) ₂SO ₃, ammonium nitrate NH ₄NO ₃With ammonium nilrite NH ₄NO ₂In the mixture, make wherein ammonium sulfite and ammonium nilrite and airborne oxygen that sufficient oxidation reaction take place, generate byproduct of ammonium sulfate (NH ₄) ₂SO ₄With ammonium nitrate NH ₄NO ₃The equation of its chemical reaction is as follows:

2(NH ₄) ₂SO ₃+O ₂＝2(NH ₄) ₂SO ₄

2NH ₄NO ₂+O ₂＝2NH ₄NO ₃

4) flue gas through desulfurization and denitrification reaction is carried out one electric precipitation again and handle, remove sulfur trioxide SO entrained in the flue gas ₃The NH of acid mist and escape ₃The ammoniacal liquor aerosol.In this process, the nanoscale sulfur trioxide SO that rises with flue gas ₃With ammoniacal liquor NH ₃Aerosol is by electric-field charge, and charged particle separates with flue gas under the effect of electric field force, and moves to and be accumulated into particle on the pole plate, can obtain to remove simultaneously the clean flue gas of multiple pollutant thus.

In above-mentioned steps 1) in, the reaction temperature of nitric oxide and hydrogen peroxide or ozone preferably is controlled in 110～130 ℃ the scope, is preferably 115～125 ℃.Like this, hydrogen peroxide or ozone can be under suitable temperature with flue gas in nitric oxide reaction fully completely takes place, the nitric oxide of the overwhelming majority is converted into nitrogen dioxide, thereby improves the denitration efficiency of whole technology.

Above-mentioned steps 1) in, the emitted dose of oxidant hydrogen peroxide or ozone is determined in following ratio: the nitric oxide production mol ratio in hydrogen peroxide or ozone and the flue gas is 1.0～1.2.Above-mentioned steps 2) in, the increment of desulfurization denitrification agent ammoniacal liquor is determined in following ratio: the ammoniacal liquor that desulfurization is required and the mol ratio of sulfur dioxide in flue gas are 2.1～2.3, and the mol ratio of nitrogen dioxide is 1.1～1.3 in ammoniacal liquor that denitration is required and the flue gas.Angle from requirement has guaranteed desulfurization denitrification agent ammoniacal liquor and nitrogen oxide type NO like this, on the one hand _xReact cmpletely with sulfur dioxide, also avoided on the other hand dropping into too much desulfurization denitrification agent and the new pollution and the wasting of resources of producing.

For realizing the custom-designed wet ammonia flue gas cleaning system that removes multiple pollutant simultaneously of above-mentioned technology, comprise pre-dedusting device and reaction absorption tower.Flue between described pre-dedusting device and the reaction absorption tower is provided with hydrogen peroxide or ozone injection apparatus, enters after flue gas process hydrogen peroxide or the ozone treatment in the reaction absorption tower.Described reaction absorption tower is provided with stock tank district, bottom, flue gas input area, bottom, middle part flue gas water conservancy diversion and absorbent spray district and upper smoke pneumoelectric dedusting area from bottom to top successively.Wherein: the stock tank district, bottom on reaction absorption tower is connected with ammoniacal liquor device for supplying and air apparatus for feeding, the flue gas input area, bottom on reaction absorption tower is provided with gas approach, the middle part flue gas water conservancy diversion on reaction absorption tower and absorbent spray district interlaced arrangement have multiple tracks flue gas guide ring and a plurality of ammonia spray floor, the upper smoke pneumoelectric dedusting area on reaction absorption tower is furnished with electric cleaner, links to each other by external slurry circulating pump between stock tank district, bottom and the ammonia spray floor on reaction absorption tower.

Further, the bottom plasma discharge mouth on above-mentioned reaction absorption tower links to each other with the import of cyclone separator by slurry pump, and the underflow head piece of cyclone separator links to each other with the import of dehydrator, and the solid outlet of dehydrator links to each other with drier.Simultaneously, the last overfall of cyclone separator and the liquid outlet of dehydrator are all linked to each other with the import of intermediate box, the outlet of intermediate box links to each other with the stock tank district, bottom on reaction absorption tower by reclaiming circulating pump.Thus, can realize that the comprehensive process of byproduct of ammonium sulfate that desulphurization denitration is generated and ammonium nitrate slurries handles, after its separation, dehydration, drying, but directly become stock's ammonium sulfate and ammonium nitrate fertilizer, simultaneously the raffinate of separating is sent back to the desulphurization denitration tower and continue circulation, realize the innoxious and recycling of desulphurization denitration product.

Compared with prior art, the invention has the advantages that:

At first, the present invention will remove the process of multiple pollutant in the flue gas and the system that adopted organically is combined into a complete process system, both simplify technological process, reduce occupation area of equipment, significantly reduce the investment and the operating cost of equipment again.

Secondly, the present invention at first becomes nitrogen dioxide with content in the flue gas at the oxidation of nitric oxide more than 90% by hydrogen peroxide or ozone, adopts ammoniacal liquor to remove sulfur in smoke and nitrogen dioxide simultaneously as absorbent again.Because nitrogen dioxide is easier is absorbed by ammoniacal liquor, so the present invention effectively overcome the low defective of denitration efficiency in the traditional wet ammonia type flue gas desulfurizing denitration technology, and its denitration efficiency can reach more than 90%.

Once more, the present invention is by the flue gas guide ring of interlaced arrangement and the synergy of ammonia spray layer, flue gas is assembled to reaction axis place, absorption tower in the spraying layer of flowing through, force flue gas that turbulent flow takes place on the one hand, dead angle on the other hand removes smoke, make flue gas in the reaction absorption tower, both realize even flow field optimization by different level, continually strengthen the mass transfer between flue gas and the desulfurization denitrification agent slurries again, effectively prevented of the influence of desulfurization denitrification agent slurries spray blind area, reaction edge, absorption tower to absorption efficiency, thereby make gas-liquid mass transfer efficient can improve 20～30%, its desulfuration efficiency can be increased to more than 95%, and smoke evacuation meets sulfur dioxide SO fully ₂The national standard of discharging.

At last, the present invention collects sulfur trioxide in smoke gas SO by the electric cleaner that is arranged on reaction top, absorption tower ₃With ammoniacal liquor NH ₃Aerosol, and can further remove micronic dust in the flue gas.Particularly collect ammoniacal liquor NH ₃Aerosol can effectively solve the escaping of ammonia problem in the ammonia process of desulfurization denitrating technique.By above processing, sulfur trioxide SO ₃Aerocolloidal arresting efficiency can reach more than 90%, ammoniacal liquor NH in the clean flue gas after the processing ₃Concentration is less than 1mg/m ³, satisfy the control requirement of country fully, for a big obstacle has been cleared away in the popularization of wet ammonia flue gas treatment process to foul gas.

Description of drawings

Accompanying drawing is a kind of structural representation that removes the wet ammonia flue gas cleaning system of multiple pollutant simultaneously.

The specific embodiment

Below at a coal-fired power station boiler unit, the present invention is described in further detail in conjunction with the accompanying drawings:

Remove the wet ammonia flue gas cleaning system of multiple pollutant in the time of shown in the figure, comprise the pre-dedusting device 4 that is arranged on coal-burning boiler unit 1 exhaust pass, and the reaction absorption tower 14 that is used for flue gas desulfurization and denitrification.Pre-dedusting device 4 adopts the electrostatic precipitator of the board-like level Four electric field structure of line, can collect the grit more than 99.5% in the flue gas, its outlet conduit is divided into two-way, gas baffle 5, the air-introduced machine 6 of leading up on its flue directly link to each other with chimney 7, and another road links to each other with the cooling side-entrance of heat exchanger 9 by gas baffle 5, the booster fan 8 on its flue.Flue between the import on the cooling side outlet of heat exchanger 9 and reaction absorption tower 14 is provided with hydrogen peroxide or ozone injection apparatus 10, hydrogen peroxide or ozone injection apparatus 10 adopt the spray nozzle that has barrier, can some female pipes and arm specifically be set according to the flue cross-sectional sizes, and the quantity of atomizer on the arm, flue gas enters in the reaction absorption tower 14 after through hydrogen peroxide or ozone treatment.

Reaction absorption tower 14 is a tubular construction, is provided with stock tank district, bottom, flue gas input area, bottom, middle part flue gas water conservancy diversion and absorbent spray district and upper smoke pneumoelectric dedusting area from bottom to top successively.Wherein: the stock tank district, bottom on reaction absorption tower 14 is connected with ammoniacal liquor device for supplying 23 and air apparatus for feeding 15.The gas approach of the flue gas input area, bottom on reaction absorption tower 14 links to each other with the outlet of hydrogen peroxide or ozone injection apparatus 10.The middle part flue gas water conservancy diversion on reaction absorption tower 14 and absorbent spray district interlaced arrangement have multiple tracks flue gas guide ring 13 and a plurality of ammonia spray floor 12, the number of combinations of flue gas guide ring 13 and ammonia spray layer 12 depends primarily on parameters such as institute's exhaust gas volumn to be processed, 3～5 groups of flue gas guide rings 13 and ammonia spray layer 12 are complementary, and can realize good gas-liquid mass transfer.More specifically, the preferred triangular structure in ring cross section of flue gas guide ring 12, its outstanding angle β=80～120 °, projecting height h=0.1～0.15D with respect to reaction absorption tower 14 endless inner wall, above-mentioned D is the internal diameter or the equivalent internal diameter on reaction absorption tower 14, is expressed as with mathematical formulae: $D=\sqrt{(4*A)/\mathrm{\π}},$ Wherein A is the cross-sectional area on reaction absorption tower 14, and π is a pi.Multiple tracks flue gas guide ring 13 and ammonia spray layer 12 be interlaced arrangement successively from bottom to top, can force flue gas to converge to the center on reaction absorption tower 14, has both eliminated the spray dead angle of edge, flue gas flow field is more evenly optimized, thereby significantly improved gas-liquid mass transfer.

The upper smoke pneumoelectric dedusting area on reaction absorption tower 14 is furnished with electric cleaner 11, in order to collect remaining SO in the flue gas ₃The NH of acid mist and escape ₃Aerosol.Electric cleaner 11 preferably adopts the wet cottrell with inner flush clean nozzle, so at first makes the SO by electric field ₃And NH ₃Particulate is charged, and charged particulate is moved to pole plate and is accumulated into graininess in the effect of electric field force, utilizes the souring of its gravity and water spray again, makes SO ₃And NH ₃Particle drops to the absorbent spray district of electric cleaner 11 belows, participates in reaction once more, finally eliminates the protozoa SO of acid rain ₃With foul gas NH ₃, significantly improve the smoke evacuation quality.

Link to each other by external slurry circulating pump 16 between stock tank district, bottom and the ammonia spray floor 12 on reaction absorption tower 14, uninterruptedly circulate to guarantee the ammoniacal liquor absorbent.The bottom plasma discharge mouth on reaction absorption tower 14 links to each other with the import of cyclone separator 19 by slurry pump 17, the underflow head piece of cyclone separator 19 links to each other with the import of dehydrator 20, the solid outlet of dehydrator 20 links to each other with drier 22, the last overfall of cyclone separator 19 all links to each other with the import of intermediate box 21 with the liquid outlet of dehydrator 20, the outlet of intermediate box 21 links to each other with the stock tank district, bottom on reaction absorption tower 14 by reclaiming circulating pump 18, constitutes desulphurization denitration accessory substance treatment system thus.Slurry pump 17 will react slurries pump drainage in the stock tank district, 14 bottom, absorption tower to desulphurization denitration accessory substance treatment system, through separate, dehydration obtains ammonium sulfate and ammonium nitrate crystals, drying obtains desulfurizing byproduct ammonium sulfate and ammonium nitrate fertilizer again.And the waste liquid that is separated pumps into the stock tank district, bottom of reacting absorption tower 14 by reclaiming circulating pump 18, circulates again.

The top exhanst gas outlet on reaction absorption tower 14 links to each other with the intensification side-entrance of heat exchanger 9, and the intensification side outlet of heat exchanger 9 links to each other with chimney 7 by gas baffle 5, air-introduced machine 6 on its flue successively.

The wet ammonia flue gas cleaning technology that removes multiple pollutant simultaneously of the present invention is such:

At first, after the flue gas that coal-burning boiler unit 1 produces passes through economizer 2, air preheater 3, enter in the pre-dedusting device 4, can remove the flying dust more than 99.5% in the flue gas.Whether flue gas is discharged from pre-dedusting device 4 outlet, be arranged on gas baffle 5 on its flue and control flue gas automatically according to the operation conditions on reaction absorption tower 14 and enter and react absorption tower 14.If flue gas does not enter reaction absorption tower 14, then directly send into chimney 7 by air-introduced machine 6.If flue gas enters reaction absorption tower 14,,, flue gas is reduced to is suitable in the temperature range of desulfurization and denitrification reaction cooling in the flue gas elder generation suction heat exchanger 9 then by the mobile power resources that provide of booster fan 8 for flue gas.

Then, flue gas through cooling enters in hydrogen peroxide or the ozone injection apparatus 10, the emitted dose of hydrogen peroxide or ozone is determined in following ratio: the nitric oxide production mol ratio in hydrogen peroxide or ozone and the flue gas is 1.0～1.2, the reaction temperature of nitric oxide and hydrogen peroxide or ozone is controlled in 110～130 ℃ the scope, be preferably 115～125 ℃, so that sufficient oxidation reaction takes place entrained hydrogen peroxide or the ozone of nitric oxide NO in the flue gas and atomizing air, generate nitrogen dioxide NO ₂In this process, also have part sulfur dioxide SO ₂Be oxidized to sulfur trioxide SO ₃

Secondly, flue gas through oxidation processes reacts the absorption tower 14 from the gas approach input, be upward through flue gas guide ring 13 and the ammonia spray layer 12 of interlaced arrangement in reaction absorption tower 14 central region, flue gas guide ring 13 can force the flue gas of each level to assemble, eliminate the spray dead angle, flue gas flow field is further evenly distributed to place, reaction 14 axle center, absorption tower.Meanwhile, ammoniacal liquor device for supplying 23 constantly is 25～30% ammoniacal liquor to reaction absorbent stock tank district, 14 bottom, absorption tower implantation quality percent concentration, and by slurry circulating pump 16 it is delivered to ammonia spray layer 12 and sprays circulation.Flue gas contacts with the ammoniacal liquor drop is reverse, and the gas-liquid two-phase reaction takes place, and removes sulfur in smoke SO ₂With nitrogen dioxide NO ₂, generate ammonium sulfite, ammonium nitrate and ammonium nilrite mixture simultaneously.Wherein: the increment of desulfurization denitrification agent ammoniacal liquor is determined in following ratio: the ammoniacal liquor that desulfurization is required and the mol ratio of sulfur dioxide in flue gas are 2.1～2.3, fully react to guarantee sulfur in smoke and desulfurization absorbent, and its desulfuration efficiency is more than 95%; The mol ratio of nitrogen dioxide is 1.1～1.3 in ammoniacal liquor that denitration is required and the flue gas, with the denitration efficiency that guarantees flue gas more than 90%.

Once more, the ammonium sulfite that is generated, ammonium nitrate and ammonium nilrite mix slurry fall into the stock tank district, bottom on reaction absorption tower 14, air generation oxidation reaction with feeding from air apparatus for feeding 15 makes ammonium sulfite and ammonium nilrite be converted into ammonium sulfate and ammonium nitrate slurries.Ammonium sulfate and ammonium nitrate slurries from the plasma discharge mouth output on reaction absorption tower 14, are delivered to cyclone separator 19 by slurry pump 17 again, carry out slurries and separate in cyclone separator 19, and intermediate box 21 is returned in overflow on it, and underflow stream enters dehydrator 20.Enter the drier 22 from the ammonium sulfate and the ammonium nitrate crystals of the output of dehydrator 20 solid outlets, drying is sent into the warehouse or is squeezed into cake after handling, and obtains byproduct of ammonium sulfate and ammonium nitrate fertilizer again.Also flow into intermediate box 21 from the waste liquid of dehydrator 20 liquid outlets output, the waste liquid in the intermediate box 21 enters reaction absorption tower 14 by reclaiming circulating pump 18 again, realizes recycling.

At last, arrive in the electric cleaner 11 on reaction 14 tops, absorption tower entrained SO in the flue gas through the flue gas of desulfurization and denitrification reaction ₃The NH of acid mist and escape ₃Aerosol and residual a spot of grit are charged in electric field, and become trapped on the dust collecting pole plate SO ₃The NH of acid mist and escape ₃Aerosol is accumulated into big particle, and under the water souring and self gravitation effect of electric cleaner 11 inner washer jets, these particles drop in the ammonia spray layer 12 of electric cleaner 11 belows, participates in reaction once more, thereby makes SO ₃The NH of acid mist and escape ₃Aerocolloidal arresting efficiency is brought up to more than 90%, the NH in the flue gas after the processing ₃Concentration is less than 1mg/m ³, satisfy the control requirement of country to foul gas.The clean flue gas that removes multiple pollutant enters in the smoke re-heater 9 from the exhanst gas outlet output on reaction absorption tower 14, and the temperature of flue gas is elevated to about 80 ℃, enters chimney 7 by gas baffle 5, air-introduced machine 6 successively again.The temperature that suitably promotes flue gas can effectively prevent flue gas corrosion flue and chimney.

Claims (10)

1, a kind of wet ammonia flue gas cleaning technology that removes multiple pollutant simultaneously comprises that the flue gas to needing desulfurization carries out pre-dust removal process, and it is characterized in that: this technology also comprises the steps:

1) adopt hydrogen peroxide or ozone as oxidant,, as atomizing medium it evenly is ejected into through in the flue gas of pre-dust removal process with air, make in the flue gas nitric oxide both with hydrogen peroxide or ozone generation chemical reaction, also, generate nitrogen dioxide gas with airborne oxygen generation chemical reaction;

2) adopt ammoniacal liquor as desulfurization denitrification agent, it be ejected into through in the flue gas of oxidation processes, make sulfur in smoke and nitrogen dioxide respectively with ammoniacal liquor generation chemical reaction, generate ammonium sulfite, ammonium nitrate and ammonium nilrite mixture;

3) adopt air as oxidant, it is ejected in ammonium sulfite, ammonium nitrate and the ammonium nilrite mixture of desulfurization and denitrification reaction generation, make wherein ammonium sulfite and ammonium nilrite and airborne oxygen that sufficient oxidation reaction take place, generate byproduct of ammonium sulfate and ammonium nitrate;

4) flue gas through desulfurization and denitrification reaction is carried out one electric precipitation again and handle, remove the sulfur trioxide acid mist entrained in the flue gas and the ammoniacal liquor aerosol of escape, can obtain to remove simultaneously the clean flue gas of multiple pollutant.

2, the wet ammonia flue gas cleaning technology that removes multiple pollutant simultaneously according to claim 1 is characterized in that: in the said step 1), the reaction temperature of nitric oxide and hydrogen peroxide or ozone is controlled in 110～130 ℃ the scope.

3, the wet ammonia flue gas cleaning technology that removes multiple pollutant simultaneously according to claim 1, it is characterized in that: in the said step 1), the emitted dose of oxidant hydrogen peroxide or ozone is determined in following ratio: the nitric oxide production mol ratio in hydrogen peroxide or ozone and the flue gas is 1.0～1.2.

4, the wet ammonia flue gas cleaning technology that removes multiple pollutant simultaneously according to claim 1, it is characterized in that: said step 2), the increment of desulfurization denitrification agent ammoniacal liquor is determined in following ratio: the ammoniacal liquor that desulfurization is required and the mol ratio of sulfur dioxide in flue gas are 2.1～2.3, and the mol ratio of nitrogen dioxide is 1.1～1.3 in ammoniacal liquor that denitration is required and the flue gas.

5, a kind ofly adopt the described technology of claim 1 and the custom-designed wet ammonia flue gas cleaning system that removes multiple pollutant simultaneously, comprise pre-dedusting device (4) and reaction absorption tower (14), it is characterized in that: the flue between described pre-dedusting device (4) and the reaction absorption tower (14) is provided with hydrogen peroxide or ozone injection apparatus (10), enters in the reaction absorption tower (14) after flue gas process hydrogen peroxide or the ozone treatment; Described reaction absorption tower (14) is provided with stock tank district, bottom from bottom to top successively, flue gas input area, bottom, middle part flue gas water conservancy diversion and absorbent spray district, and upper smoke pneumoelectric dedusting area, wherein: the stock tank district, bottom on reaction absorption tower (14) is connected with ammoniacal liquor device for supplying (23) and air apparatus for feeding (15), the flue gas input area, bottom on reaction absorption tower (14) is provided with gas approach, the middle part flue gas water conservancy diversion on reaction absorption tower (14) and absorbent spray district interlaced arrangement have multiple tracks flue gas guide ring (13) and a plurality of ammonia spray floor (12), the upper smoke pneumoelectric dedusting area on reaction absorption tower (14) is furnished with electric cleaner (11), links to each other by external slurry circulating pump (16) between stock tank district, bottom and the ammonia spray floor (12) on reaction absorption tower (14).

6, the wet ammonia flue gas cleaning system that removes multiple pollutant simultaneously according to claim 5, it is characterized in that: the bottom plasma discharge mouth on said reaction absorption tower (14) links to each other with the import of cyclone separator (19) by slurry pump (17), the underflow head piece of cyclone separator (19) links to each other with the import of dehydrator (20), and the solid outlet of dehydrator (20) links to each other with drier (22).

7, the wet ammonia flue gas cleaning system that removes multiple pollutant simultaneously according to claim 6, it is characterized in that: the liquid outlet of the last overfall of said cyclone separator (19) and dehydrator (20) all links to each other with the import of intermediate box (21), and the outlet of intermediate box (21) links to each other with the stock tank district, bottom on reaction absorption tower (14) by reclaiming circulating pump (18).

8, according to claim 5 or the 6 or 7 described wet ammonia flue gas cleaning systems that remove multiple pollutant simultaneously, it is characterized in that: the ring cross section structure triangular in shape of said flue gas guide ring (13), its outstanding angle β=80～120 ° with respect to reaction absorption tower (14) endless inner wall, projecting height h=0.1～0.15D, wherein D is the internal diameter or the equivalent internal diameter on reaction absorption tower (14).

9, according to claim 5 or the 6 or 7 described wet ammonia flue gas cleaning systems that remove multiple pollutant simultaneously, it is characterized in that: said flue gas guide ring (13) is provided with 3～5 roads, and corresponding ammonia spray layer (12) is provided with 3～5.

10, according to claim 5 or the 6 or 7 described wet ammonia flue gas cleaning systems that remove multiple pollutant simultaneously, it is characterized in that: said electric cleaner (11) is for having the wet cottrell of inner flush clean nozzle.