CN201578985U - Double-shaft collision flow smoke gas synchronous desulfuration and denitration device - Google Patents
Double-shaft collision flow smoke gas synchronous desulfuration and denitration device Download PDFInfo
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- CN201578985U CN201578985U CN201020104664XU CN201020104664U CN201578985U CN 201578985 U CN201578985 U CN 201578985U CN 201020104664X U CN201020104664X U CN 201020104664XU CN 201020104664 U CN201020104664 U CN 201020104664U CN 201578985 U CN201578985 U CN 201578985U
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Abstract
The utility model discloses a double-shaft collision flow smoke gas synchronous desulfuration and denitration device which consists of a heat exchanger, a double-shaft collision flow premixing tubes, a collision flow reactor body, an effective demister, an absorption liquid circulating pump, a sump, a valve, a centrifuge, a separating liquid pump, an ammonia pump, an ammonia liquid distribution tank, a urea liquid pump, a urea liquid distribution tank, an air compressor and a dirt catcher; the outlet of the dirt catcher is connected with the inlet of polluted smoke gas of the heat exchanger; the outlet of polluted smoke gas of the heat exchanger is respectively connected with the inlets of smoke gas of the double-shaft collision flow premixing tubes; the absorption liquid is stored in the sump and the sump is connected with the lower end of the collision flow reactor body; the double-shaft collision flow premixing tube is arranged on the collision flow reactor body and is arranged on the sump; the double-shaft collision flow premixing tube comprises two pairs of collision flow premixing tubes; each pair of collision flow premixing tubes comprises two premixing tubes which are oppositely arranged; absorption liquid atomizing nozzles are arranged in the premixing tubes; and the two pairs of collision flow premixing tubes mutually form a orthogonality relation in the same horizontal plane.
Description
Technical field
The invention belongs to the technical field of atmospheric environment protection.Relate to a kind of flue gas combined desulfurization and denitration device, particularly relate to a kind of twin shaft impinging stream flue gas and desulfurizing and denitrifying device that utilizes urea/ammoniacal liquor/additive solution.
Background technology
Sulfur dioxide and nitrogen oxide are the bigger gaseous contaminants of influence in the atmosphere pollution, human body, environment and the ecosystem are had very big harm, along with the increasingly stringent of environmental requirement, NO
xAnd SO
2The problem of discharging more and more receives publicity.Sulfur dioxide and nitrogen oxide mainly stem from the combustion process of fossil fuels such as coal, oil, and the fume emission of the roasting of ore, smelting process, wherein various burning boilers particularly power plant boiler smoke evacuation have characteristics such as concentration is low, exhaust gas volumn is big, floating dust is many and are difficult to improvement.In the conventional art, discharging sulfur dioxide in flue gas and purification of nitrogen oxides technology are normally separately carried out desulfurization and denitration, complicated huge, defectives such as initial outlay is big, operating cost height that this has caused the discharging flue gas purification system have seriously restricted the actual enforcement of discharging flue gas desulfurization and denitrification.Flue gas desulfurization technique is mainly based on limestone-gypsum wet method, rotating spraying semidry method, in-furnace calcium spraying afterbody humidification activation, sea water desulfuration, electron beam desulfurization, flue gas circulating fluidized bed desulfurization etc., wherein the wet type limestone-based process is the tail flue gas desulfur technology that is most widely used in the world now, its subject matter is that the solubility of absorbent (lime or lime stone) is little, utilization rate is low, and the waste residue amount is big; And SCR technology (SCR), SNCR technology (SNCR), electronic beam method, impulse electric corona method, complex compound absorption process and urea absorption process etc., comparatively ripe gas denitrifying technology at present in service mainly is SCR technology, SNCR technology and SNCR/SCR combination technique, but the SCR method exists the initial investment expense higher, operating temperature range is narrow, and exist ammonia to leak, can generate N
2O, and shortcoming such as the easy inactivation of catalyst; And the SNCR denitration efficiency is lower, and the ammonia leakage is many, causes secondary pollution.Countries in the world in recent years, especially industrially developed country has all carried out desulphurization denitration Study on Technology exploitation simultaneously in succession, and carried out certain commercial Application, electron beam irradiation method, impulse electric corona method, active carbon adsorption, NOxSO technology and Pahlman flue gas desulfurization and denitration technique etc. are abroad arranged at present, but China still lack at present this type of mature technology or because of energy consumption and cost too high and incompatible.Therefore, seek the flue gases purification of a kind of efficient, low-cost, low operating cost, non-secondary pollution, become the problem of China environmental protection researcher concern.
The ammonia type flue gas desulfurizing technology starts from the beginning of the seventies in last century, and ammonia desulfurizing process is at first studied by states such as Japan and Italy, and succeeds in succession.Because in the general coal-fired flue-gas, the oxidizability of nitrogen oxide is 5%-10%, and NH
4HSO
3To (NH
4)
2SO
3Absorption of N O
xInhibited, the denitration function of single ammoniacal liquor absorption process is very little, and there are problems such as the aerosol of ammonia and emission intensity in the single ammonia process of desulfurization.Therefore, reasonable coupling by urea and ammoniacal liquor, not only can reduce the single urea operating cost of desulfurizing and denitrifying process simultaneously greatly, also can effectively prevent problems such as the aerosol of the ammonia that single ammonia desulfurizing process exists and emission intensity, can also utilize ammonia to absorb the intermediate product (NH that sulfur dioxide produces simultaneously
4)
2SO
3Absorption of N O again
x, and the inhibit feature that utilizes urea that nitrous acid is decomposed reduces the probability that decomposes generation NO again of the intermediate product in the absorption reaction process.Experimental study is found: by the use of uniting of cheap ammoniacal liquor or industrial deposed ammonia and urea liquid, not only can greatly reduce the cost of absorbent, can guarantee the associating removal effect of higher oxysulfide and nitrogen oxide simultaneously.
Research and analyse discovery, SO in the flue gas
2Absorption in urea/ammonia spirit be in the liquid phase with the quick GAS ABSORPTION of irreversible chemical reaction, and NO in the flue gas
xAbsorption in urea/ammonia spirit is with the GAS ABSORPTION of chemical reaction at a slow speed in the liquid phase.In order to guarantee to remove efficiently simultaneously SO in the flue gas
2And NO
x, the haptoreaction of flue gas and absorbent solution must be controlled the regular hour.Yet the prolongation in reaction time certainly will cause the increase greatly of desulfurization and denitrification reaction device volume simultaneously, and this will increase the equipment investment expense greatly, is that reality institute is unacceptable.Obviously, NO
2Has characteristic soluble in water, easy absorption; Influence NO in the flue gas
XThe main factor of the GAS ABSORPTION of chemical reaction is NO extremely low solubility in water at a slow speed in urea/ammonia spirit, and NO accounts for NO in the coal-fired flue-gas
xMore than 90% of total amount.Therefore, how further to improve in the flue gas oxidizability of nitrogen oxide and (amount to NO
2Account for NO in the flue gas
xRatio) be to influence NO in the flue gas
xThe key problem in science of absorption reaction speed and efficient in absorption liquid.Discover, realize liquid phase catalytic oxidation NO, improve the oxidizability of nitrogen oxide in the flue gas, and promote the collaborative absorption of intermediate product, will greatly improve follow-up absorbent solution NO to pollutant in the flue gas by suitable additive
XAbsorption rate and efficient, be to solve NO
xMethod and approach that the essence that absorbs chemical reaction process at a slow speed in urea/ammonia spirit is effective and feasible.
In addition, it is the absorption tower that the height of flue gas and desulfurizing and denitrifying efficient has the main equipment of great related, traditional wet desulfurizing process with the stability of operation and absorption reactor thermally, and it has several forms such as plate column, packed tower and spray column.In the gas-liquid two-phase mass transfer of absorption tower, because effectively contact area is little, low by the volume transmission quality coefficient of the mass transport process of liquid film control in the unit volume, so this kind equipment is bulky, space availability ratio and device fabrication intensity is low, equipment investment is big.The impinging stream technology is especially one of the effective method of transmittance process of external diffusion control of strengthening transfer process, and carry-over factor is than high several times to tens of conventional method times.Discover: the impinging stream absorber compared with traditional tower bigger than phase contact area, mass tranfer coefficient is high, desulfurization off sulfide effect good, energy loss is low, volume is little, advantage of simple structure.In view of this, take all factors into consideration various factors such as investment, operation stability, energy consumption, structure, it is more efficient, reasonable, feasible to design absorption reactor thermally with twin shaft impinging stream technology, can realize improving gas cleaning efficient, reduces total system equipment investment and operating cost.
Chinese invention patent (application number: 91105599.1) proposed to carry out the while desulphurization denitration with ammoniacal liquor, sulphur ammonium or its acidic aqueous solution, urea and compound powder thereof or its aqueous solution different temperatures section in stove.Chinese invention patent (application number: 91105599.1) be used for the furnace high-temperature section, certainly will bring high energy loss, and problem such as stove internal corrosion.The present invention is that (mixed solution is united and removed sulfur dioxide and nitrogen oxide method and device thereof in my previous patent of invention that proposes, application number: on the basis 200710020999.6), introduce bromide ion or chlorion or ammonium persulfate etc. and make the absorbing catalyst of NOx, make the process of absorption reaction at a slow speed of NO be converted into the fast Absorption course of reaction; Adopt the impinging stream technology to strengthen mixing and mass transport process between the gas-liquid greatly simultaneously, promote to absorb chemical reaction, improve reactor, reduce reactor volume, and simplify structure of reactor, cut down the consumption of energy than phase contact area.At present, domestic only have a utility model patent (ZL 200820042363.1) to adopt the percussion flow technology to be applied to the alkali lye sweetening process, still do not have twin shaft impinging stream technology both at home and abroad and be applied to denitration and combined desulfurization and denitration process, and urea/ammonia spirit is cut off beyond example especially by liquid-phase catalysis and in conjunction with the efficient associating flue gas desulfurization and denitrification process that twin shaft impinging stream technology realizes.
Summary of the invention
The present invention be intended to provide a kind of simple in structure, overall efficiency is high, cost of investment is low, operating cost is little, the twin shaft impinging stream flue gas and desulfurizing and denitrifying device of non-secondary pollution, the present invention can improve denitrification efficiency, especially can improve denitration efficiency.
The present invention adopts following technical scheme:
A kind of twin shaft impinging stream flue gas and desulfurizing and denitrifying device, by heat exchanger, twin shaft impinging stream premix barrel, the impinging stream reactor body, efficient demister, the absorption liquid circulating pump, collecting tank, valve, centrifuge, separate liquid pump, aqua ammonia pump, the ammoniacal liquor Agitation Tank, urea solution pump, the urea liquid Agitation Tank, air compressor machine and deduster are formed, the outlet of deduster is connected with the import of the pollution flue gas of heat exchanger, the pollution exhanst gas outlet of heat exchanger is connected with the smoke inlet of twin shaft impinging stream premix barrel respectively, in described collecting tank, store absorbent solution and collecting tank and be connected in the lower end of impinging stream reactor body, described twin shaft impinging stream premix barrel is located on the impinging stream reactor body and is positioned at collecting tank, described twin shaft impinging stream premix barrel comprises 2 pairs of impinging stream premix barrel, every pair of impinging stream premix barrel comprises 2 premix barrel of arranging in opposite directions, in premix barrel, be provided with the absorption liquid atomizer, described 2 pairs of impinging stream premix barrel constitute same level face orthogonality relation mutually, described collecting tank is connected with the inlet of absorption liquid atomizer by the absorption liquid circulating pump, the liquid outlet of collecting tank is communicated with the import of centrifuge by valve, the outlet of centrifuge is communicated with collecting tank by separating liquid pump, described ammoniacal liquor Agitation Tank is communicated with collecting tank by aqua ammonia pump, described urea liquid Agitation Tank is communicated with collecting tank by urea solution pump, the outlet of described air compressor machine is communicated with collecting tank, described efficient demister is located at the upper end of impinging stream reactor body, and the outlet of efficient demister is connected with the purification smoke inlet of heat exchanger.
Compared with prior art, the present invention has following characteristic and advantage:
1. applied widely, this process and equipment can be used for all kinds of SO of containing
2And NO
xTail gas and the removing of flue gas, comprise boiler for domestic, Industrial Boiler, Industrial Stoves, station boiler, metallurgical tail gas, chemical industry tail gas; SO to high and low concentration
2And NO
xFlue gas all can effectively be removed.
2. adopt twin shaft impinging stream flue gas and desulfurizing and denitrifying device, its overall efficiency height, SO
2Total removal efficiency is 95%～98%, NO
xTotal removal efficiency is 75%～90% (single shaft impinging stream and twin shaft impinging stream combined desulfurization and denitration relatively see Table 1), and it removes performance and can compare favourably with at present popular desulfurization of wet type limestone-based process and SCR method denitration combination, has reclaimed byproduct of ammonium sulfate simultaneously.
The comparison of head-on collision of table 1 single shaft and twin shaft head-on collision combined desulfurization and denitration overall efficiency
3. twin shaft impinging stream flue gas and desulfurizing and denitrifying device, adopt the urea/ammoniacal liquor drop of flue gas and atomizing at first in premix barrel, to carry out premixed, improved the uniformity of gas-liquid mixed, and carried acceleration by flue gas, helped improving the penetration depth of drop in the later stage impinging stream at this stage drop.
4. the present invention adopts twin shaft gas-liquid mixed stream to clash into (the orthogonal thereto symmetrical same level face of twin shaft is arranged) in opposite directions in the impinging stream reactor, the twin shaft head-on collision makes gas-liquid not only vertically clash into outside the mixing consumingly on the head-on collision direction, and will inevitably be to laterally flowing at the back gas-liquid mixture that vertically clashes, because having adopted twin shaft quadrature symmetry same level face arranges, the gas-liquid mixture of lateral flow will inevitably be subjected to the percussion from another impinging stream on the orthogonal direction, the gas-liquid mixture of the lateral flow that impinging stream causes is pushed to the nucleus that clashes once more, this makes gas-liquid prolong in the time of staying of head-on collision core space, mixing is laterally strengthened, the gas-liquid turbulence is stronger, mix more even, to in the whole impinging stream reaction zone between gas-liquid the raising of mass transfer and chemical reaction rate more favourable, improved pollutant removing efficient and speed.But when adopting how right impinging stream to arrange, owing to can't realize same level face quadrature arrangement, phase mutual interference between impinging stream is bigger, pollutant removing efficient and speed improve not obvious, yet the head-on collision fluxion is many more, cost of equipment and energy consumption also can increase, and the whole synthesis cost performance descends, so the twin shaft head-on collision is more reasonable.Also can adopt downward-sloping head-on collision (this moment, inclination alpha was not more than 10 °) during the gas-liquid head-on collision downwards, this makes gas-liquid impingement retrodeviate in reactor liquid level direction motion (to go out flow path direction opposite with gas), prolonged the reaction time of gas-liquid in reactor, helped the pollutant removing sufficient reacting and finish.
5. the present invention is owing to adopt twin shaft impinging stream technology, ammonia and urea mixed solution the turbulence of absorption reactor thermally inner height with mix, greatly improved and absorbed the mass transfer rate of chemical reaction, thereby accelerated the absorption rate of NOx; Simultaneously, absorption liquid is carried accelerated motion by flue gas after being atomized into fine drop by atomizer in the twin shaft premix barrel, enter the impinging stream zone, the drop that is accelerated under effect of inertia in opposite directions the head-on collision another fluerics internal motion, owing to be subjected to the gas-flow resistance effect of impinging stream in opposite directions, liquid drop movement slows down gradually, afterwards counter motion under the effect of air-flow in opposite directions; And so forth, drop just forms damped oscillation back under the effect of jet in opposite directions like this, has prolonged the time of contact of drop and flue gas, makes the effective rate of utilization raising of absorption liquid.Therefore, not only help improving gas cleaning speed and efficient, also help the volume that reduces absorption reactor thermally.
6. in twin shaft impinging stream flue gas and desulfurizing and denitrifying device, its product is the solubility height in water, and no any inner member in the reactor, and less scaling, security of operation is stable, and is easy to maintenance, is easy to control; In addition, no inner member helps reducing SR in the reactor.
7. because the present invention adopts twin shaft impinging stream technology, the height turbulence makes that the alternate mixing of gas-liquid is very even between gas-liquid, has greatly improved absorption reaction speed and efficient, thereby has made liquid-gas ratio reduce (1.5～6l/m greatly
3), can reduce the energy consumption of absorption liquid circulating pump greatly.
8. the present invention adopts triethanolamine, ethylenediamine, KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate etc. as liquid-phase catalyst, has quickened absorbent solution to NO
xAbsorption reaction speed, make the process of absorption reaction at a slow speed of NO be converted into the fast Absorption course of reaction, reduced the volume of absorption reactor thermally; Triethanolamine, ethylenediamine etc. also have the absorption liquid of making trend alkalescent direction simultaneously, have prevented the corrosion of system equipment.
9. the present invention organically combines impinging stream technology and system for desulfuration and denitration, making the present invention compare with SCR method denitration combination with at present popular wet type limestone-based process desulfurization has obtained simplifying greatly, save system space, saved initial outlay cost and operating cost.
10. the utility model has been realized the inner closed circulation of absorption liquid, and no secondary discharging of waste liquid problem has realized that resource reclaims and the dual notion of environmental protection.
Description of drawings
Fig. 1 is that urea/ammonia spirit of the present invention adds the flue gas combined system flow chart that removes sulfur dioxide and nitrogen oxide of liquid phase catalysis twin shaft impinging stream, heat exchanger 1, twin shaft impinging stream premix barrel 2, absorption liquid atomizer 3, impinging stream reactor body 4, efficient demister 5, absorption liquid circulating pump 6, collecting tank 7, valve 8, centrifuge 9 is wherein arranged, separate liquid pump 10, aqua ammonia pump 11, ammoniacal liquor Agitation Tank 12, urea solution pump 13, urea liquid Agitation Tank 14, air compressor machine 15, deduster 16.
Fig. 2 is that twin shaft impinging stream horizontal plane of the present invention is arranged schematic diagram.
Fig. 3 is the twin shaft impinging stream of the present invention schematic diagram that is in tilted layout.
Fig. 4 is the premix barrel structural representation.
The specific embodiment
A kind of twin shaft impinging stream flue gas and desulfurizing and denitrifying device, by heat exchanger 1, twin shaft impinging stream premix barrel 2, impinging stream reactor body 4, efficient demister 5, absorption liquid circulating pump 6, collecting tank 7, valve 8, centrifuge 9, separate liquid pump 10, aqua ammonia pump 11, ammoniacal liquor Agitation Tank 12, urea solution pump 13, urea liquid Agitation Tank 14, air compressor machine 15 and deduster 16 are formed, the outlet of deduster 16 is connected with the import of the pollution flue gas of heat exchanger 1, the pollution exhanst gas outlet of heat exchanger 1 is connected with the smoke inlet of twin shaft impinging stream premix barrel 2 respectively, in described collecting tank 7, store absorbent solution and collecting tank 7 and be connected in the lower end of impinging stream reactor body 4, described twin shaft impinging stream premix barrel 2 is located on the impinging stream reactor body 4 and is positioned at collecting tank 7, described twin shaft impinging stream premix barrel 2 comprises 2 pairs of impinging stream premix barrel 2, every pair of impinging stream premix barrel comprises 2 premix barrel of arranging in opposite directions, in premix barrel, be provided with absorption liquid atomizer 3, described 2 pairs of impinging stream premix barrel constitute same level face orthogonality relation mutually, described collecting tank 7 is connected with the inlet of absorption liquid atomizer 3 by absorption liquid circulating pump 6, the liquid outlet of collecting tank 7 is communicated with the import of centrifuge 9 by valve 8, the outlet of centrifuge 9 is communicated with collecting tank 7 by separating liquid pump 10, described ammoniacal liquor Agitation Tank 12 is communicated with collecting tank 7 by aqua ammonia pump 11, described urea liquid Agitation Tank 14 is communicated with collecting tank 7 by urea solution pump 13, the outlet of described air compressor machine 15 is communicated with collecting tank 7, described efficient demister 5 is located at the upper end of impinging stream reactor body 4, and the outlet of efficient demister 5 is connected with the purification smoke inlet of heat exchanger 1.
Below the specific embodiment of the present invention is made more detailed explanation:
The present invention is the efficient associating flue gas desulfurization and denitration technique that a kind of wet method urea/ammoniacal liquor/additive mixed solution is realized by twin shaft impinging stream technology, this technology has overcome the shortcoming of conventional flue gas purifying technique function singleness, system complex, and its overall efficiency height, system is simple, cost of investment is low, operating cost is little, non-secondary pollution.It is characterized in that: adopt urea/ammonia spirit as while desulphurization denitration absorption liquid, with triethanolamine, ethylenediamine, KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate etc. as catalytic additive, flue gas carries out the gas-liquid height with absorption liquid and mixes in the impinging stream reactor, efficiently realize desulphurization denitration process simultaneously apace, absorption liquid makes byproduct of ammonium sulfate through oxidation again, waste liquid is realized the inner loop utilization, does not have any discharging of waste liquid.
Basic process is as follows:
Contain at first enter heat exchanger after pollution flue gas (the about 160 ℃) dedusting of sulfur dioxide and nitrogen oxide and be cooled to 100 ℃～110 ℃ after, (premix barrel also can be downward-sloping to enter twin shaft impinging stream premix barrel, be not more than 10 ° with the inclination angle a of horizontal plane), flue gas at first with blending have a catalytic action additive (wherein, the mass percent that triethanolamine or ethylenediamine add is 0.005%～0.025% of urea/ammonia spirit, and KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate etc. be urea/ammonia spirit quality 0.5%～10%) the urea that is atomized/ammoniacal liquor mixed solution (ammonia spirit concentration be 2%～10% and urea concentration be 2%～6%, the pH value of absorbent solution maintains 4.8～9, and the temperature of absorption liquid is controlled at 30 ℃～80 ℃) (liquid-gas ratio is 1.5～6L/m to carry out the gas-liquid premixed in mixing tube
3), the absorption liquid of atomizing drops in the twin shaft premix barrel and is quickened by flue gas, enters then in the impinging stream reactor absorption chamber, gas-liquid mixed stream in opposite directions clashes into twin shaft mutually at this, gas-liquid high turbulence, mixing make mixing between gas-liquid, mass transfer rate accelerate the SO in the flue gas
2And NO
xAt this by the while absorbing and removing; Drop owing to damped oscillation takes place in head-on collision, has prolonged the time of contact of atomized drop and flue gas, and then has improved the effective rate of utilization of absorption liquid in impingement region simultaneously.Big drop sedimentation under the gravity effect enters collecting tank in the gas-liquid after the twin shaft head-on collision, droplets entrained enters collecting tank in the flue gas after efficient demister separates, and flue gas after being purified (flue-gas temperature is 55 ℃～70 ℃) is warming up to 75 ℃～90 ℃ through heat exchanger again and enters atmosphere.Circulating absorption solution in the collecting tank is pumped into by the absorption liquid circulating pump and is atomized into trickle drop and the premixed of incoming flow flue gas in the absorption liquid atomizer; Ammonia spirit in the ammoniacal liquor liquid pool is pumped in the collecting tank by aqua ammonia pump; Solution in urea liquid and the additive Agitation Tank is pumped in the collecting tank by urea solution pump; Air carries out oxidation reaction in air compressor machine blasts twin shaft impinging stream reactor body; The ammonium sulfate of collecting tank inner bottom part crystallization enters centrifuge through valve, separates to obtain 98% ammonia sulfate crystal and remove to be dried to finished product, and the solution after centrifuge separates pumps in the collecting tank by separating liquid pump.SO in this method flue gas
2Total removal efficiency is 95%～98%, NO
xTotal removal efficiency is 75%～90%, obtains byproduct of ammonium sulfate, and realizes the absorption liquid inner loop, the discharging of non-secondary pollution thing.
Make liquid-phase catalyst with triethanolamine, ethylenediamine, KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate etc., the principle of urea liquid or urea and ammonia spirit while desulphurization denitration is as follows:
Urea is soluble in water, and its aqueous solution is extremely weak alkalescence, near neutral.Hydrolysis can take place and generate aminoquinoxaline in urea in water, be the endothermic reaction.Water at normal temperature is separated very slow, and the component of aminoquinoxaline is less in the solution; When solution temperature surpassed 70 ℃, hydrolysis was obviously accelerated.Urea is a kind of strong reducing agent, can faster nitrous acid be reduced to nitrogen under the condition of acidity.Pollutant NO in the coal-fired flue-gas
XAnd SO
2Following reaction (O in the flue gas may take place in urea liquid
2Content is 3～5%):
2NO+O
2→2NO
2 (1)
2HNO
2+(NH
2)
2CO→3H
2O+CO
2+2N
2 (9)
SO
2+(NH
2)
2CO+2H
2O→(NH
4)
2SO
3+CO
2 (10)
2(NH
4)
2SO
3+O
2→2(NH
4)
2SO
4 (11)
4(NH
4)
2SO
3+2NO
2→4(NH
4)
2SO
4+N
2 (12)
2(NH
4)
2SO
3+2NO→2(NH
4)
2SO
4+N
2 (13)
By reacting (8) HNO as can be seen
2Decomposition can cause the generation once more of NO, and urea meeting and HNO
2(9) generation N reacts
2And CO
2Thereby, the generation of inhibitory reaction (8), and quickened reaction (4), (5) and (6) positive reaction process.From the reaction (10) as can be seen, urea also will with SO
2Generate (NH
4)
2SO
3, and (NH
4)
2SO
3Also has certain NO that removes
2With the function of NO, see reaction (12) and (13).Therefore, the existence of flue gas desulfurization and denitrification process sulphur oxide has facilitation to removing of nitrogen oxide simultaneously.
Ammonia is a kind of good alkaline absorbent, analyzes from absorbing chemism, and the absorption of sulfur dioxide is acid-base neutralization reaction, and reaction rate is fast, react completely, and absorbent utilization rate height, byproduct are ammonium sulfate or ammonium sulfite.Pollutant NO in the coal-fired flue-gas
XAnd SO
2Contingent key reaction also has following reaction (O in the flue gas except that reaction (1)～(8) in ammonia spirit
2Content is 3～5%):
SO
2+2NH
3+H
2O→(NH
4)
2SO
3 (14)
(NH
4)
2SO
3+SO
2+H
2O→2NH
4HSO
3 (15)
NH
4HSO
3+NH
3→(NH
4)
2SO
3 (16)
2(NH
4)
2SO
3+O
2→2(NH
4)
2SO
4 (17)
4(NH
4)
2SO
3+2NO
2→4(NH
4)
2SO
4+N
2 (18)
4(NH
4)HSO
3+2NO
2→4(NH
4)HSO
4+N
2 (19)
2(NH
4)
2SO
3+2NO→2(NH
4)
2SO
4+N
2 (20)
(NH
4)OH+HNO
3→NH
4NO
3+H
2O (21)
(NH
4)OH+HNO
2→NH
4NO
2+H
2O (22)
NH
4NO
2→N
2+2H
2O (23)
In the ammoniacal liquor sweetening process, its main intermediate product is (NH
4)
2SO
3(NH
4) HSO
3, all have certain absorption NO
xAbility.Discover SO
2Absorption in ammonia spirit be in the liquid phase with the quick GAS ABSORPTION of irreversible chemical reaction, and NO in the flue gas
xAbsorption in ammonia spirit is with the GAS ABSORPTION of chemical reaction at a slow speed in the liquid phase.Because in the coal-fired flue-gas, the oxidizability of nitrogen oxide is generally 5%-10%, reaction (18), (19), (20) in the single ammoniacal liquor absorption process, (21) and (22) denitration efficiency are very little, but also the phenomenon (seeing reaction (8)) that exists nitrous acid to decompose again to generate NO.Thereby the actual denitration function of single ammoniacal liquor is very little.
From reaction (1)～(23) we as can be seen, final primary product (O in the flue gas under the condition that aerobic exists that urea liquid, ammonia spirit generate in the flue gas desulfurization and denitrification process simultaneously
2Content is 3～5%) be ammonium sulfate and ammonium nitrate, can carry out comprehensive reutilization by the method for condensing crystallizing.Therefore, the cheap advantage and the SO of comprehensive utilization ammoniacal liquor (useless ammonia)
2Absorption in ammonia spirit is with the quick gas absorption process of irreversible chemical reaction in the liquid phase, and in conjunction with the denitration function of the intermediate product that forms in ammoniacal liquor (useless ammonia) sweetening process, and the denitration function of urea generates the mechanism of NO by force with the decomposition again that can suppress the intermediate product in the denitrification process, reasonable coupling by urea and ammoniacal liquor, not only will reduce the operating cost of single urea desulfurizing and denitrifying process greatly, removal effect when can guarantee higher oxysulfide and nitrogen oxide simultaneously.In addition, the concentration that the existence of urea can corresponding reduction ammoniacal liquor, and aqueous solution of urea wants high than the volatilization temperature of ammonia spirit can play problems such as the aerosol of the ammonia that the single ammonia process of desulfurization of certain improvement exists and emission intensity.
Because in the coal-fired flue-gas, the oxidizability of nitrogen oxide is generally 5%-10%, the denitration efficiency of reaction (18), (19), (20), (21) and (22) is generally very little.Experimental study finds that under the catalytic action of introducing suitable additive, desulfurization, denitration efficiency are improved, and especially denitration efficiency improves very big.
Experimental study finds that urea liquid absorbing NOxes such as KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate have catalytic action preferably, and that can improve nitrogen oxide significantly removes speed and removal efficiency; And additives such as triethanolamine, ethylenediamine not only have catalysis in course of reaction, also have buffering effect.Catalytic action is meant accelerated reaction speed or suppresses side reaction control the Direction of Reaction and process take place; Buffering effect is meant regulates the absorption liquid pH value, makes absorption liquid trend alkalescent direction, prevents the corrosion of equipment.
System's connected mode
Flue gas after the dedusting is after pipeline enters heat exchanger 1 cooling, enter twin shaft impinging stream premix barrel 2 through pipeline, in twin shaft impinging stream premix barrel 2 flue gas with absorb drop from the atomizing of atomizer 3 and carry out premixed, drop is accelerated at this simultaneously, and the gas-liquid mixture behind the premix enters impinging stream reactor body 4 generation air-flow twin shafts and clashes into absorption reaction in opposite directions; Purification flue gas behind the twin shaft bump absorption reaction upwards enters efficient demister 5, enters heat exchanger 1 by pipeline again and heats up the back by in the pipeline feeding chimney; Circulating absorption solution is pumped into by absorption liquid circulating pump 6 through pipeline and forms trickle atomized drop and the premixed of incoming flow flue gas in the absorption liquid atomizer 3 in the collecting tank 7; Ammonia spirit in the ammoniacal liquor liquid pool 12 through pipeline pump into by aqua ammonia pump 11 with collecting tank 7 in; Urea liquid in urea liquid and the additive Agitation Tank 14 and additive are pumped in the collecting tank 7 by urea solution pump 13 through pipeline; Air carries out oxidation reaction through air compressor machine 15 in pipeline blasts impinging stream reactor body 4; The ammonium sulfate of collecting tank 7 inner bottom part crystallizations enters centrifuge 9 through valve 8 again through pipeline, separates to obtain 98% ammonia sulfate crystal and remove to be dried to finished product, and the solution after centrifuge 9 separates pumps in the collecting tank 7 by separating liquid pump 10 through pipeline.
Describe the most preferred embodiment that urea/ammonia spirit of the present invention adds liquid phase catalysis twin shaft impinging stream flue gas combined desulfurization and denitration method in detail with reference to Fig. 1.
Contain sulfur dioxide (400mg/Nm
3～6000mg/Nm
3) and nitrogen oxide (200mg/Nm
3～4000mg/Nm
3) flue gas (about 160 ℃) dedusting after, after pipeline enters heat exchanger 1 and is cooled to 100～110 ℃, enter twin shaft impinging stream premix barrel 2, flue gas at first in the twin shaft premix barrel with from the blending of atomizer 3 have the additive of catalytic action (additive can be any in triethanolamine, ethylenediamine, KBr, ammonium bromide, potassium chloride, ammonium chloride, the ammonium persulfate etc., also can be any combination in triethanolamine or ethylenediamine and KBr, ammonium bromide, potassium chloride, ammonium chloride, the ammonium persulfate etc.Wherein, the mass percent that triethanolamine or ethylenediamine add is 0.005%～0.025% of urea/ammonia spirit, and the mass percent of addings such as KBr, ammonium bromide, potassium chloride, ammonium chloride, ammonium persulfate is 0.5%～10%) the urea that is atomized/ammoniacal liquor mixed solution (ammonia spirit concentration be 2%～10% and urea concentration be 2%～6%, the pH value of absorbent solution maintains 4.8～9, temperature is controlled at 30 ℃～80 ℃), (liquid-gas ratio is 1.5～6L/m to carry out the gas-liquid premixed in premix barrel
3The twin shaft premix barrel can adopt downward-sloping, be not more than 10 ° with horizontal plane inclination angle a, see Fig. 3), the absorption liquid of atomizing drops in the premix barrel and is quickened by flue gas, enters then in the impinging stream reactor body 4, gas-liquid mixed stream in opposite directions carries out twin shaft at this and clashes into mutually, gas-liquid high turbulence, mixing make mixing between gas-liquid, mass transfer rate accelerate the SO in the flue gas
2And NO
xRemoved (when the twin shaft premix barrel adopts when downward-sloping, the gas-liquid deflection collecting tank 7 liquid level directions motion of bump back has prolonged the time of staying of gas-liquid in reactor, helps improving the removal efficiency of flue gas pollutant) by the while fast Absorption at this; Drop owing to violent damped oscillation takes place in the twin shaft head-on collision, has prolonged the time of contact of atomized drop and flue gas greatly, and then has improved the effective rate of utilization of absorption liquid in the head-on collision district simultaneously.The flue gas superficial linear velocity in a column is controlled at 2.5～4m/s in the twin shaft impinging stream reactor body 4.Big drop sedimentation under the gravity effect enters collecting tank 7 in the gas-liquid after the twin shaft head-on collision, droplets entrained enters collecting tank 7 in the flue gas after efficient demister 5 separates, and flue gas after being purified (flue-gas temperature is 55 ℃～70 ℃) is warming up to 75 ℃～90 ℃ through heat exchanger 1 again and enters atmosphere.Circulating absorption solution (pH value of absorbent solution maintains 4.8～9, and temperature is controlled at 30 ℃～80 ℃) in the collecting tank 7 is pumped into by absorption liquid circulating pump 6 and is atomized into trickle drop and the premixed of incoming flow flue gas in the absorption liquid atomizer 3; Ammonia spirit in the ammoniacal liquor liquid pool 12 (ammonia spirit concentration is 10%～15%) is pumped in the collecting tank 7 by aqua ammonia pump 11; Solution in the urea liquid Agitation Tank 14 (urea concentration is 10%～20%) is pumped in the collecting tank 7 by urea solution pump 13; Blasting compressed air will react the sulfite oxidation that generates and become ammonium sulfate in collecting tank 7, the ammonium sulfate of collecting tank 7 intercrystallines is deposited on the bottom, after reaching finite concentration, enter centrifuge 9 through valve 8 and carry out Separation of Solid and Liquid, obtain 98% ammonia sulfate crystal, the solution after the separation pumps in the collecting tank 7 through separating liquid pump 10.SO in this method flue gas
2Total removal efficiency is 95%～98%, NO
xTotal removal efficiency is 75%～90%, obtains byproduct of ammonium sulfate, and realizes the absorption liquid inner loop, the discharging of non-secondary pollution thing.
Claims (1)
1. twin shaft impinging stream flue gas and desulfurizing and denitrifying device, it is characterized in that, by heat exchanger (1), twin shaft impinging stream premix barrel (2), impinging stream reactor body (4), efficient demister (5), absorption liquid circulating pump (6), collecting tank (7), valve (8), centrifuge (9), separate liquid pump (10), aqua ammonia pump (11), ammoniacal liquor Agitation Tank (12), urea solution pump (13), urea liquid Agitation Tank (14), air compressor machine (15) and deduster (16) are formed, the outlet of deduster (16) is connected with the import of the pollution flue gas of heat exchanger (1), the pollution exhanst gas outlet of heat exchanger (1) is connected with the smoke inlet of twin shaft impinging stream premix barrel (2) respectively, in described collecting tank (7), store absorbent solution and collecting tank (7) and be connected in the lower end of impinging stream reactor body (4), described twin shaft impinging stream premix barrel (2) is located on the impinging stream reactor body (4) and is positioned at collecting tank (7), described twin shaft impinging stream premix barrel (2) comprises 2 pairs of impinging stream premix barrel (2), every pair of impinging stream premix barrel comprises 2 premix barrel of arranging in opposite directions, in premix barrel, be provided with absorption liquid atomizer (3), described 2 pairs of impinging stream premix barrel constitute same level face orthogonality relation mutually, described collecting tank (7) is connected with the inlet of absorption liquid atomizer (3) by absorption liquid circulating pump (6), the liquid outlet of collecting tank (7) is communicated with the import of centrifuge (9) by valve (8), the outlet of centrifuge (9) is communicated with collecting tank (7) by separating liquid pump (10), described ammoniacal liquor Agitation Tank (12) is communicated with collecting tank (7) by aqua ammonia pump (11), described urea liquid Agitation Tank (14) is communicated with collecting tank (7) by urea solution pump (13), the outlet of described air compressor machine (15) is communicated with collecting tank (7), described efficient demister (5) is located at the upper end of impinging stream reactor body (4), and the outlet of efficient demister (5) is connected with the purification smoke inlet of heat exchanger (1).
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|---|---|---|---|
| CN201020104664XU CN201578985U (en) | 2010-01-29 | 2010-01-29 | Double-shaft collision flow smoke gas synchronous desulfuration and denitration device |
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|---|---|---|---|
| CN201020104664XU CN201578985U (en) | 2010-01-29 | 2010-01-29 | Double-shaft collision flow smoke gas synchronous desulfuration and denitration device |
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| CN201578985U true CN201578985U (en) | 2010-09-15 |
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| CN111282423B (en) * | 2020-03-05 | 2020-11-10 | 上海汇舸环保科技有限公司 | Desulfurization and denitrification treatment method for industrial pollution emission waste gas |
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