0001]The present invention, CO in the exhaust gas 2 in the process of recovery and removal of, CO 2 CO using exhaust gas treatment apparatus and it inhibited the degradation of the absorbent 2 relates collecting device.
BACKGROUND
[0002]Combustion equipment (e.g. a boiler, a gas turbine, etc.) CO in the flue gas in (hereinafter referred to as "exhaust gas") from 2 to remove, CO 2 drawn into the absorption tower, CO 2 is brought into contact with the absorption liquid, in the exhaust gas of CO 2 it has been proposed to absorb the liquid absorbent. The CO 2 CO absorbed 2 absorbing solution is fed to the absorption solution regenerator, heating by steam from the reboiler, CO 2 dissipates, high-purity CO 2 with is collected, CO 2 absorption liquid to regenerate the, CO 2 has the feed circulated recycled to the absorber.
[0003]
　Also, in the exhaust gas discharged from the combustion equipment, such as nitrogen dioxide (NO 2 if it contains), NO in the exhaust gas 2 caused component CO 2 there is a problem that accumulate in the absorbing liquid. Therefore, the accumulated components were removed CO 2 Frequency of reclaiming operation to play absorbing liquid is increased, since the operating costs are increased, CO 2 in the upstream of the recovery device, the removal of nitrogen oxides in the exhaust gas by installing a nitrogen oxide removal device, a process for removing nitrogen oxides has been proposed (Patent Document 1). Moreover, nitrogen oxides and sulfur oxides in the exhaust gas is removed by amine compounds, it has also been proposed a process for decomposing (Patent Document 2).
CITATION
Patent Document
[0004]
Patent Document 1: JP 2013-244454 Patent Publication
Patent Document 2: JP 2013-202523 JP
Summary of the Invention
Problems that the Invention is to Solve
[0005]
　However, in the case of proposals for removing nitrogen oxides using an amine compound as described in Patent Document 2, the absorption liquid which absorbed the nitrogen oxides in the nitrogen component removing tank, of the absorbing liquid with the amide acid There is a need to decompose the nitrate ion and nitrite ion, it is necessary to discard the absorption liquid, there is a problem that increase the amount of waste.
[0006]
　Furthermore, CO 2 or when the exhaust gas treatment apparatus nitrogen oxide removal equipment is not installed in the recovery unit prior to flow, the fluctuation of the operation state of the combustion apparatus such as a gas turbine, NO in the exhaust gas 2 increases the generation amount case, CO 2 NO by reclaiming process in the recovery unit 2 from the removal frequency of due storage component increases, there is a problem that operating costs are increased.
[0007]
　In view of the above problems, when the removal of nitrogen oxides in the exhaust gas, as well as reuse of nitrogen oxides absorption liquid, the exhaust gas treatment apparatus and it is possible to reduce the rate of residue at the time of reproduction process CO with 2 and to provide a collecting device.
Means for Solving the Problems
[0008]
　The first aspect of the present invention to solve the above problems, is discharged from the combustion apparatus, by introducing a gas containing at least nitrogen oxides and carbon dioxide, nitrogen oxides and nitrogen oxides absorbed in the flue gas connect the nitrogen oxide absorption unit for absorbing and removing by liquid, and an exhaust gas discharge line for discharging the treated exhaust gas to remove nitrogen oxides in the flue gas, and a bottom portion and a top portion of the nitrogen oxide absorption unit, the nitrogen oxide a nitrogen oxide absorption liquid circulation line for circulating objects absorbing solution, branches from the nitrogen oxide absorption liquid circulation line, and the nitrogen oxide absorbing solution withdrawing nitrogen oxide absorbing liquid draw-out line the circulating extraction It is heated regeneration process the nitrogen oxide absorbing solution, and discharged gas containing at least nitrogen monoxide and carbon dioxide, and nitrogen oxides absorption liquid heating reproducing portion for obtaining a nitrogen oxide absorbing solution regeneration liquid, the nitrogen Outgassing from the oxide absorbing solution heated regeneration unit, and the discharge gas line for introducing into the exhaust gas discharge line, the nitrogen oxide absorbing solution regeneration liquid from the nitrogen oxide absorbing solution heated regeneration unit, the nitrogen oxide absorption regeneration liquid discharge line for introducing the liquid circulation line, the exhaust gas treatment apparatus characterized by comprising a certain.
[0009]
　The second aspect, in the first aspect, in the exhaust gas treatment apparatus characterized by having an alkali supply unit for supplying an alkaline agent to the nitrogen oxide absorption solution heated regeneration unit.
[0010]
　The third invention is the invention of the first or second, the nitrogen oxide absorption liquid heating reproducing unit, a first reclaimer for indirect heating by steam the nitrogen oxide absorbing liquid was withdrawn, the first provided release steam line to release the release vapor from reclaimer, that comprises a first gas-liquid separator for gas-liquid separation and release gas and nitrogen oxide absorbing solution regeneration liquid from being discharged steam in exhaust gas treatment apparatus characterized.
[0011]
　The fourth invention is, in the invention of the first or 2, wherein the nitrogen oxide absorbing liquid thermal regeneration unit, nitrogen oxides absorbing solution regeneration with reboiler said withdrawn nitrogen oxide absorption liquid is indirectly heated by steam a tower, NO and CO from the top of said nitrogen oxide absorbing solution regeneration tower 2 provided release steam line to release the release vapor containing, from the released vapor and nitrogen oxide absorbing solution regeneration liquid and gas released the exhaust gas treatment apparatus characterized by comprising a second gas-liquid separator for gas-liquid separation is.
[0012]
　According to a fifth invention, in the fourth invention, the nitrogen oxide absorption regeneration liquid withdrawn from the bottom of the nitrogen oxide absorption regeneration tower was heated regeneration treatment, a discharge gas including at least nitrogen monoxide and carbon dioxide , in exhaust gas treatment apparatus characterized by comprising a second reclaimer obtaining the nitrogen oxide absorbing solution regeneration solution.
[0013]
　According to a sixth aspect, in any one invention of the first to fifth, wherein the nitrogen oxide absorbing liquid is in the exhaust gas treatment apparatus, characterized in that an amine solution or an alkaline solution containing a tertiary amine.
[0014]
　A seventh invention is an exhaust gas treatment apparatus of any one invention of the first to sixth, introduced by the exhaust gas discharge line, CO in the exhaust gas mixed with the discharge gas 2 and CO 2 is brought into contact with absorption liquid Te CO 2 CO removing 2 and absorption tower, CO 2 CO reproduces rich solution that has absorbed by the steam reboiler 2 and the absorbent regenerator, the CO 2 with withdrawing the rich solution from the absorber column, the CO 2 and the rich solution supply line to be introduced into the absorbent regenerator side, the CO 2 CO reproduced by the absorbent regenerator 2 lean solution is dissipated the CO 2 with withdrawing from the absorption liquid regenerator, the CO 2 introducing into the absorber, CO 2 to the lean-solution supply line to recycle as an absorbing solution, wherein the lean supply line withdrawn lean solution, a third reclaimer to play lean solution, characterized by comprising CO 2 in recovery device.
[0015]
　Advantageously, in the seventh invention, branched from the discharge gas line, a portion of the effluent gas the CO 2 and having a discharge gas branch line and introduced into the bottom of the absorbing solution regeneration tower CO 2 in recovery device.
[0016]
　A ninth aspect of the invention of the seventh or eighth, the withdrawn reclaimer effluent from the bottom of the third reclaimer, said reclaimer effluent is introduced into extraction liquid of the nitrogen oxide absorbing liquid reclaimer CO and having a discharge fluid introduction line 2 in recovery device.
[0017]
　A tenth invention is, in any one invention of the seventh to ninth, the CO 2 CO, wherein the absorption liquid, that at least one component of the absorbent component of the nitrogen oxide absorbing liquid common 2 is in the recovery system.
Effect of the invention
[0018]
　According to the present invention, the nitrogen oxides in the exhaust gas thereby removing nitrogen oxides absorption liquid, the nitrogen oxides NOx absorbent having absorbed heat to play, reuse nitrogen oxide absorbing liquid can. Further, when the thermal regeneration, the nitrite nitrogen oxides absorption liquid dissipates will release as nitric oxide (NO), it is possible to reduce the percentage of residues at the time of reproduction processing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
[1] Figure 1 is a schematic view of the exhaust gas processing apparatus according to the first embodiment.
FIG. 2 is a schematic view of the exhaust gas processing apparatus according to the second embodiment.
FIG. 3 is a schematic view of the exhaust gas processing apparatus according to a third embodiment.
[4] FIG. 4 is a schematic diagram of another air pollution control apparatus according to the third embodiment.
FIG. 5 is, CO according to Example 4 2 is a schematic diagram showing the structure of a recovery device.
FIG. 6 is another CO according to a fourth embodiment 2 is a schematic diagram showing the structure of a recovery device.
DESCRIPTION OF THE INVENTION
[0020]
　With reference to the accompanying drawings, illustrating preferred embodiments of the present invention in detail. It is not intended the invention be limited by this example, also, if the embodiment there are a plurality, i.e., an constitute a combination of each embodiment.
Example 1
[0021]
　Figure 1 is a schematic view of the exhaust gas processing apparatus according to the first embodiment. As shown in FIG. 1, the exhaust gas processing apparatus 10A according to the first embodiment is discharged from the combustion device (not shown), at least nitrogen oxides (NOx) and carbon dioxide (CO 2 introduced exhaust gas 11 containing) exhaust gas introduction line L to 1 have a nitrogen oxide absorbing unit 13 for absorbing and removing nitrogen oxides in the exhaust gas 11 of nitrogen oxides absorbing liquid (first absorbing liquid) 12 by the nitrogen oxides in the exhaust gas 11 exhaust gas discharge line L for discharging the exhaust gas 11A is removed 3 and connects the bottom portion 13a and the top portion 13b of the nitrogen oxide absorption unit 13, nitrogen oxide absorption liquid circulation line L circulating nitrogen oxide absorbing liquid 12 4 and , nitrogen oxide absorption liquid circulation line L 4 is branched from the nitrogen oxides absorption liquid draw-out line L extracting a portion 12a of the nitrogen oxide absorbing solution 12 circulating 5 and, withdrawn nitrogen oxides absorbing liquid by heating 12 And reproduction processing, at least nitrogen monoxide (NO) and carbon dioxide (CO 2 ) and discharge gas 21 containing nitrogen oxide absorbing solution regeneration liquid (first regenerant) 22 and nitrogen oxide absorption liquid heating reproducing portion for obtaining a 23, and nitrogen oxide absorbing solution heated regeneration unit 23 the exhaust gas discharge line L 3 connecting the, release gas 21 from the nitrogen oxides absorption liquid heating reproducing unit 23, the exhaust gas discharge line L 3 emitted gas line to be introduced into L 6When a nitrogen oxide absorbing solution heated regeneration unit 23 the nitrogen oxide absorption liquid circulation line L 4 connects the, the nitrogen oxide absorbing solution regeneration liquid 22 from the nitrogen oxides absorption liquid heating reproducing unit 23, the nitrogen oxides absorption liquid circulation line L 4 regenerant discharge line L is introduced into the 7 and comprises a.
[0022]
　In this embodiment, the exhaust gas introduction line L to introduce exhaust gas 11 to the nitrogen oxide absorption unit 13 1 in the middle of, and provided with a flue gas cooler 51 for cooling the exhaust gas 11, the top 51b from the bottom 51a of the exhaust gas cooling tower 51 connected circulation line L toward 2 to cool the exhaust gas 11 in advance by the cooling water 52 circulating. Here, in FIG. 1, reference numeral P 1 ~ P 3 is a liquid feed pump for feeding a solution.
[0023]
　The nitrogen oxide absorbing portion 13 a NOx using, CO 2 in nitrogen oxides in the exhaust gas 11 including the (NOx) recovering method, first, for example, containing NOx from combustion apparatus for a gas turbine or the like (not shown) exhaust gas 11 is fed to flue gas cooler 51 is cooled by cooling water 52 circulating here and sent to the nitrogen oxide absorption section 13.
[0024]
　In the nitrogen oxide absorption section 13, the exhaust gas 11 is contacted countercurrently with nitrogen oxide absorbing liquid 12, the nitrogen oxides in the exhaust gas 11 is absorbed by the nitrogen oxide absorbing liquid 12 by a chemical reaction. In this reaction, nitrogen oxides, nitrate (HNO 3 - ), nitrite (HNO 2 - a).
[0025]
　Exhaust gas 11A after nitrogen oxides have been removed in a nitrogen oxides absorbing portion 13, the exhaust gas discharge line L connected to the top portion 13b of the nitrogen oxide absorbing portion 13 3 is discharged out of the system by.
[0026]
　Further, the nitrogen oxide absorbing liquid 12, nitrogen oxide absorption liquid circulation line L 4 is circulated reused by, and absorbing and removing nitrogen oxides in the exhaust gas 11. Then, (if the ion concentration of, for example, nitrous acid exceeds a predetermined threshold) when the accumulation amount reaches a predetermined amount of nitrogen oxides NOx in the absorption liquid 12, nitrogen oxide absorption liquid circulation line L 4 from some 12a of the nitrogen oxide absorbing liquid 12 to circulate nitrogen oxide absorption liquid extraction line L 5 withdrawn from. This withdrawal is nitrogen oxide absorption liquid draw-out line L 5 valve V provided in the 1 performed by opening and closing the.
[0027]
　Nitrogen oxides absorption liquid 12 withdrawn is introduced into the nitrogen oxide absorption solution heated regeneration unit 23, where it is heated by the heat source, is then vapor-liquid separation treatment, and reproduced as nitrogen oxide absorbing solution 12 there.
[0028]
　As the nitrogen oxide absorption liquid heating reproducing unit 23, as long as it can be released by heating the nitrogen oxides stored in the nitrogen oxide absorbing liquid 12, is not particularly limited, for example, distillation mention may be made of the tower, reclaimer, the regeneration tower or the like having a reboiler.
[0029]
　Then, contained in the nitrogen oxide absorbing solution heated regeneration unit 23, in discharge gas 21 which is gas-liquid separated from the vapor released by heating treatment when it is played, at least nitrogen monoxide (NO) is . Incidentally, the nitrogen oxide absorbing liquid 12 CO 2 when having an absorbent capacity at the same time carbon dioxide in the released gas 21 (CO 2 ) are also included.
[0030]
　The discharge gas 21, tip exhaust gas discharge line L 3 emitted gas line L connecting to 6 via the nitrogen oxides at nitrogen oxide absorbing portion 13 is introduced into the exhaust gas 11A which is removed, out of the system It is discharged.
[0031]
　On the other hand, nitrogen oxide absorbing solution regeneration liquid 22 from the nitrogen oxides absorption liquid heating reproducing unit 23, the nitrogen oxide absorption liquid circulation line L 4 regenerant discharge line L is connected to 7 nitrogen oxides circulating through the is introduced into the absorption liquid 12 is reused as a nitrogen oxide absorbing liquid 12.
[0032]
　Residue 25 after the heat treatment of the nitrogen oxide absorption solution heated regeneration unit 23 the line L out residual渣排 8 discharged from, is separately processed. Incidentally, separately makeup water 26 is supplied to the nitrogen oxide absorption liquid heating reproducing unit 23, thereby suppressing the increase in the concentration of the solution in nitrogen oxide absorption liquid heating reproducing unit 23.
[0033]
　Wherein the nitrogen oxide absorbing liquid 12 to remove absorbed nitrogen oxides in the exhaust gas 11, as long as it removes absorb nitrogen oxides in the exhaust gas 11 is not particularly limited, the amine solution containing a tertiary amine or it is preferably an alkali solution. Here, to use a tertiary amine, when used a primary amine or secondary amine to produce a reaction by-product of nitrogen oxides, since the loss of the amine, is not preferable.
[0034]
　Here, as the tertiary amine, such as N- methyldiethanolamine, N- ethyldiethanolamine, N- butyl diethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, 2-di -n- butyl aminoethanol, N- ethyl - N- methyl ethanolamine, 3-dimethylamino-1-propanol, 2-dimethylamino-2-methyl-1-propanol, there may be mentioned 4-dimethylamino-1-butanol, the present invention is not limited thereto not shall.
[0035]
　Further, a tertiary amine, may be used together with a primary amine and secondary amine. In this case, the tertiary amine compound is the main component, the mixing ratio of the tertiary amine is preferably account for 55-95% by weight of the total amine. More preferably from in the range of 60 to 80 wt%.
[0036]
　In the case of using an alkali solution, the alkali concentration is from about 5 to 48% preferably with 10-25% aqueous sodium hydroxide, preferably to maintain pH6 below as pH value at the time of circulation. This is because when the pH of the circulating fluid is high, CO 2 increases excessively absorption of is because it is disadvantageous in terms of alkali consumption and energy efficiency.
[0037]
　Releasing gas line L to release emitted gas 21 from the nitrogen oxides absorption liquid heating reproducing unit 23 6 , the example provided compressor such as a vacuum pump, the interior of the nitrogen oxide absorption liquid heating reproducing unit 23 as a pressure reducing state , thereby suppressing the boiling point of the solution. In the case of boiling specified range may not be provided with the compressor.
[0038]
　Here, by the nitrogen oxide absorbing liquid 12 withdrawn in nitrogen oxide absorption liquid heating reproducing unit 23 is heated, nitrite nitrogen oxides absorbing fluid 12 is hardly dissolved in the absorbing liquid monoxide It dissipated during release steam as nitrogen (NO).
[0039]
　As described above, in the present embodiment a nitrogen oxides absorption liquid heating reproducing unit 23, nitrite nitrogen oxides absorbing liquid 12 is dissipated as nitric oxide (NO) by heating, nitrogen oxide absorbing liquid because never remain in the 12, nitrogen oxides accumulation in the nitrogen oxide absorbing liquid 12, no nitrogen oxide absorption solution heated regeneration step, degradation in device for decomposing the nitrogen oxide absorbing solution of the prior art for the case of processing, so that the emissions of residue 25 is reduced by about 0.7 times.
Example 2
[0040]
　Figure 2 is a schematic view of the exhaust gas processing apparatus according to the second embodiment. Note that the same members as in Example 1, a description thereof will be omitted given the same reference numerals. As shown in FIG. 2, the exhaust gas processing apparatus 10B according to this embodiment, the nitrogen oxide absorption liquid heating reproducing unit 23 in the exhaust gas treatment device 10A according to the first embodiment, the nitrogen oxide absorbing solution 12a which was withdrawn a first reclaimer 31A to indirect heating by steam 34, releasing steam line L to emit a first release vapors 32A from the first reclaimer 31A 9 provided in nitrogen oxides from in the first release vapors 32A a first gas-liquid separator 33A that separates the gas-liquid and absorbing solution regeneration liquid 22 and a discharge gas 21, but having a. Further, the first reclaimer 31A, a heating unit 35 for indirectly heating the inside by steam 34, and the alkaline agent supply unit 36 for supplying an alkaline agent 36a therein, a provided. In Figure 2, reference numeral 34a is a steam condensate after heat exchange.
[0041]
　In this embodiment, CO (not shown) 2 so that by introducing a reflux water from the recovery unit as makeup water 26, is diluted mixed nitrogen oxides absorbing fluid 12a and an alkali agent 36a that withdrawn. This, CO 2 recovery apparatus since a closed system, for dilution, since water balance The introduction of dilution water from the outside is bad.
[0042]
　Thus nitrogen oxide absorbing liquid (containing an amine nitrate.) 12, by adding an alkali agent (e.g. NaOH, KOH, etc.) while adjusting the 36a, and sodium or potassium sulfate, free amines from ionic state It has been in a state of such amines. Since amines resulted in this free has a vapor pressure, is included in the first release vapors 32A as vaporized material, are gas-liquid separation in the first gas-liquid separator 33A, it is recovered. The ion because no vapor pressure remains ionic state, not entrained in the first release vapors 32A.
[0043]
　Is fixed by the added alkaline agent 36a, coexisting materials without this vapor pressure, as the first reclaimer residue 37, the line L out residual渣排from the bottom of the first reclaimer 31A 8 is discharged via a separately processed that.
[0044]
　The first release vapors 32A from the first reclaimer 31A is introduced into the first gas-liquid separator 33A, the gas in the discharge gas 21 from the first release vapors 32A and nitrogen oxide absorbing solution regeneration solution 22 is liquid separation.
[0045]
　The separated release gas 21, tip exhaust gas discharge line L 3 emitted gas line L connecting to 6 via the nitrogen oxides is supplied to the exhaust gas 11A which is removed by the nitrogen oxide absorbing portion 13, It is discharged to the outside of the system.
[0046]
　Incidentally, emission gas line L to release emitted gas 21 from the first gas-liquid separator 33A 6 , the example provided compressor such as a vacuum pump, a vacuum state inside the first reclaimer 31A, the solution thereby suppressing the boiling point. In the case of boiling specified range may not be provided with the compressor.
[0047]
　On the other hand, nitrogen oxides was separated into gas and liquid absorbent solution regeneration liquid (first regenerant) 22, nitrogen oxide absorption liquid circulation line L 4 regenerant discharge line L tip is connected to 7 nitrogen circulating through the are mixed oxides absorption liquid 12 is reused as a nitrogen oxide absorbing liquid 12.
[0048]
　According to this embodiment, the first reclaimer 31A as nitrogen oxide absorption liquid heating reproducing unit 23, nitrite nitrogen oxides absorbing liquid 12 is dissipated as nitric oxide (NO) by indirect heating of the steam , since there is no stay in nitrogen oxides absorbing fluid 12, nitrogen oxides accumulation in the nitrogen oxide absorbing liquid 12, no nitrogen oxide absorption solution heated regeneration step, nitrogen oxides absorption liquid of the prior art for the case to decompose in the apparatus to decompose, so that the emissions of residue is reduced by about 0.7 times.
[0049]
　Further, nitrite nitrogen oxides reacts by absorbing the nitrogen oxide absorbing solution 12 (NO 2 - ) is, since it is removed as NO by stripping, the nitrogen oxide storage amount is reduced by that amount heating, waste of the first reclaimer residue 37 generated in the reclaiming by the addition of an alkaline agent 36a in the first reclaimer 31A is reduced.
Example 3
[0050]
　Figure 3 is a schematic view of the exhaust gas processing apparatus according to a third embodiment. Note that the same members as in Example 1 and 2, a description thereof will be omitted with the same reference numerals. As shown in FIG. 3, the exhaust gas treatment device 10C according to this embodiment, the nitrogen oxide absorption liquid heating reproducing unit 23 in the exhaust gas treatment device 10A according to the first embodiment, the nitrogen oxide absorbing solution 12a which was withdrawn a nitrogen oxide absorbent regenerator 41 that indirectly heated by steam reboiler 42, a is the gas-liquid separating discharge gas 21 from the in the second release vapors 32B emitted from the top 41a of the nitrogen oxide absorbent regenerator 41 and second gas-liquid separator 33B, those having a.
[0051]
　In this embodiment, the nitrogen oxides absorption liquid heating reproducing unit 23, the nitrogen oxide absorption liquid circulation line L 4 part 12a of the nitrogen oxide absorbing liquid 12 to be circulated from the nitrogen oxide absorbing liquid draw-out line L 5 from withdrawn, the nitrogen oxide absorption liquid draw-out line L 5 the tip of the is introduced into the inside from the top 41a of the nitrogen oxide absorbing solution regeneration tower 41, the indirect heating steam by reboiler 42, the nitrogen monoxide (NO) , carbon dioxide (CO 2 by releasing), and reproduction processing.
[0052]
　Further, the nitrogen oxide absorption liquid draw-out line L 5 and the nitrogen oxide absorbing solution regeneration liquid 22 withdrawn from the bottom portion 41b of the nitrogen oxide absorbent regenerator 41 nitrogen oxide absorption liquid circulation line L 4 is connected to the regeneration liquid discharge line L 7 at the intersection between the first heat exchanger 43 is interposed, by the nitrogen oxide absorbing solution regeneration liquid 22 to heat the nitrogen oxide absorption liquid 12a which withdrawn. This withdrawal is nitrogen oxide absorption liquid draw-out line L 5 valve V provided in the 1 performed by opening and closing the.
[0053]
　Further, in this embodiment, releasing steam line L to emit a second release vapors 32B 9 , the first cooler 45 is provided, to condense water vapor by cooling the second release steam 32B, then the It is introduced into 2 of the gas-liquid separation device 33B. Condensed condensate, as reflux water 46, reflux water line L 12 pump P to the top 41a of the nitrogen oxide absorbent regenerator 41 through 4 are sent back through.
[0054]
　According to this embodiment, in the nitrogen oxide absorbing solution regeneration tower 41 as the nitrogen oxide absorbing solution heated regeneration unit 23, in the nitrogen oxide absorbing liquid 12 flowing down in the column by indirect heating of the steam by reboiler 42 nitrous nitrate is dissipated as nitric oxide (nO), it does not remain in the nitrogen oxide absorbing liquid 12.
[0055]
　Figure 4 is a schematic diagram of another air pollution control apparatus according to the third embodiment. Note that the same members as in Example 1-3, and a description thereof will be omitted given the same reference numerals. As shown in FIG. 4, the exhaust gas treatment device 10D according to this embodiment, a portion 22a of the nitrogen oxide absorbing solution regeneration solution 22 regenerated regenerant draw-out line L 10 drawn by the second reclaimer to play processing 31B and is provided, contaminants accumulate in the nitrogen oxide absorbing solution regeneration liquid 22 is separated and removed. This withdrawal is regenerated liquid draw-out line L 10 valve V provided in the 2 performed by opening and closing the. Note that the second reclaimer 31B, and provided with a heating unit 35 for indirectly heating the inside by steam 34 and supplies the makeup water 26 and an alkali agent 36a therein.
[0056]
　In the second reclaimer 31B, coexisting substances such as amines with vapor pressure, because it is entrained in the third release vapors 32C, in a gaseous state, a third released into the bottom of the nitrogen oxide absorbent regenerator 41 vapor line L 11 are returned by the. The second reclaimer 31B, since the removal of nitrate nitrogen oxides absorbing solution regeneration liquid 22 can be continuously processed the absorption of nitrogen oxides.
[0057]
　The regeneration process of the second reclaimer 31B, when the concentration of nitrate nitrogen oxides absorbing solution regeneration liquid 22 becomes the prescribed threshold value, the valve V 2 is opened to one of the nitrogen oxide absorbing solution regeneration solution 22 withdrawn part 22a, it is sufficient to perform the reclaimer process.
[0058]
　Therefore, nitrite nitrogen oxides reacts by absorbing the nitrogen oxide absorbing liquid regeneration liquid 22 (NO 2 - ) is, since it is removed as NO by stripping, the nitrogen oxide storage amount reduced by that amount heating and, waste residue 37 generated in the reclaiming by the addition of an alkaline agent 36a in the second reclaimer 31B is reduced.
Example 4
[0059]
　5, CO according to Example 4 2 is a schematic diagram showing the structure of a recovery device. As shown in FIG. 5, CO according to Example 4 2 recovery apparatus 100A, combustion equipment such as boilers and gas turbines NOx discharged from the (not shown), SOx, CO 2 coolant exhaust gas 11 containing a flue gas cooler 51 for cooling by 52, nitrogen in the nitrogen oxide absorbing liquid that absorbs the exhaust gas 11 and nitrogen oxides by contacting the (first absorbing liquid) 12 exhaust gas 11 containing a cooled nitrogen oxides a nitrogen oxide absorbing unit 13 for absorbing an oxide, a portion of the nitrogen oxide absorption liquid 12a of nitrogen oxide absorbing solution 12 circulating withdrawn, and reproduction processing by heating, at least nitrogen monoxide (NO) and carbon dioxide (CO 2 and discharge gas 21 containing), a first reclaimer 31A is a nitrogen oxide absorbent liquid thermal regeneration section 23 to obtain nitrogen oxide absorbing solution regeneration liquid (first regenerant) 22, nitrogen oxides or things absorbing portion 13 Is discharged, the nitrogen oxides CO in the exhaust gas 11A which is absorbed and removed 2 CO removing 2 CO having a recovery section 110A 2 the absorption tower 111, CO 2 CO absorbed 2 absorbing solution (hereinafter, "rich solution 112A also referred to as ".) from 112 CO by the steam in the second reboiler 115 2 by releasing CO 2CO Play absorption liquid 2 has an absorbent solution regeneration tower 113. Then, the CO 2 in the collecting devices 100A, absorbent regenerator CO at 113 2 to remove the regeneration CO 2 absorbing solution (hereinafter, also referred to as "lean solvent 112B".) 112 CO 2 CO absorption tower 111 2 absorbing solution reused as.
[0060]
　The CO 2 recovery apparatus 100A CO using a 2 in the recovery process, first, NOx, CO 2 gas 11 from the combustion equipment of a gas turbine or the like containing, after being boosted by the exhaust gas blower (not shown), the exhaust gas It is sent to the cooling tower 51, where it is cooled by cooling water 52 is fed to the nitrogen oxide absorption section 13.
[0061]
　In the nitrogen oxide absorption section 13, the exhaust gas 11 is contacted countercurrently with nitrogen oxide absorbing liquid 12, the nitrogen oxides in the exhaust gas 11 is absorbed by the nitrogen oxide absorbing liquid 12 by a chemical reaction. In this reaction, nitrogen oxides, nitrate (NO 3 - ), nitrite (NO 2 - ) and it becomes.
[0062]
　Exhaust gas 11A after nitrogen oxides have been removed in a nitrogen oxides absorbing portion 13, the exhaust gas discharge line L connected to the top 13b of the nitrogen oxide absorbing portion 13 3 is discharged by.
[0063]
　Further, the nitrogen oxide absorbing liquid 12, nitrogen oxide absorption liquid circulation line L 4 is circulated reused by, and absorbing and removing nitrogen oxides in the exhaust gas 11. Then, when the accumulation amount of the nitrogen oxide absorbing liquid nitrogen oxides in 12 has reached a predetermined amount, the nitrogen oxide absorption liquid circulation line L 4 part 12a of nitrogen oxides of the nitrogen oxide absorbing liquid 12 to be circulated from absorption liquid discharge line L 5 withdrawn from.
[0064]
　Nitrogen oxides absorption liquid 12 withdrawn is heated regeneration process is introduced into the first reclaimer 31A, the first release vapors 32A and the gas-liquid separation process, nitrogen oxide absorbing solution regeneration liquid (first It is playing as a playback solution) 22.
[0065]
　Exhaust 11B to release gas 21 is mixed from the first gas-liquid separator 33A is then CO 2 is fed to the absorption tower 111. The CO 2 in the absorption tower 111, the exhaust gas 11B is CO is an amine absorbing solution 2 in contact countercurrent with the absorption liquid 112, CO in the exhaust gas 11B 2 are, CO by a chemical reaction 2 is absorbed in the absorption liquid 112. CO 2 CO in the recovery unit 110A 2 CO after was removed 2 flue gas. 11C, CO 2 CO supplied from the nozzle washing section 110B in the absorption tower 111 2 gas and washing water 119 circulating an absorbent solution and liquid contact, CO 2 CO accompanying the flue gas 11C 2 is absorbed fluid 112 is collected, then CO 2 purification exhaust gas 11D that has been removed is discharged out of the system.
[0066]
　Moreover, CO 2 CO was absorbed 2 rich solution 112A which is an absorption liquid 112 is pressurized by the rich solution pump (not shown), the rich solution supply line L 101 is interposed a rich lean solution heat exchanger 141 in, CO 2 CO reproduced by the absorbent regenerator 113 2 is heated by the lean solution 112B is the absorption liquid 112, CO 2 is supplied to the absorption liquid regenerator 113.
[0067]
　CO 2 rich solution 112A of upper emitted inside the tower from the absorbent regenerator 113, caused the endothermic reaction by the steam according to the second reboiler 115 which is supplied from the bottom, most of the CO 2 releasing. CO 2 CO some or most in absorbent regenerator within 113 2 CO were released 2 absorbing solution is called semi-lean solvent. The semi-lean solution, CO 2 by the time reaches the bottom of the absorbing solution regeneration tower 113, almost all of the CO 2 CO has been removed 2 becomes lean solution 112B of the absorption liquid 112. The lean solution 112B is indirectly heated by steam, a part occurs in the second reboiler 115, CO 2 is supplying steam to the interior absorbent regenerator 113.
[0068]
　On the other hand, CO 2 from the top of the absorbing solution regeneration tower 113, CO accompanied by water vapor released from the rich solution and the semi-lean solution in the tower 2 carrier gas 131 is derived, the water vapor is condensed by the condenser 132, separation drum 133 reflux water 134 is separated by, CO 2 gas 135 is discharged to the outside of the system, it is compressed by a separate compressor and recovered. The compressed and recovered CO 2 gas is separately enhanced oil recovery equipment (EOR: Enhanced Oil Recovery) or pressed into oil was used to stored in an aquifer, thereby achieving the warming.
[0069]
　CO accompanied by steam 2 and the upper portion of the absorbent regenerator 113 entrained reflux water 134 from the gas 131 is separated and refluxed with separation drum 133 at reflux water circulation pump (not shown), a third reclaimer 31C, CO 2 are respectively supplied to the wash water 119 side of the washing unit 110B of the absorption tower 111.　
[0070]
　CO played 2 lean solution 112B is an absorption liquid, the rich solution supply line L 101 and the lean-solution supply line L 102 in interposed at the intersection between been rich lean solution heat exchanger 141, the rich solution 112A is cooled by being boosted by subsequently lean solution pump (not shown), after being cooled in further lean solution cooler (not shown), CO 2 is fed into the absorption tower 111.
[0071]
　CO 2 absorbing solution regeneration tower 113 CO reproduced by 2 lean solution 112B of the absorption liquid is partially lean-solution supply line L 102 branch line L from 103 is branched by, it is introduced into the third reclaimer 31C. Then, in the third reclaimer 31C, CO was withdrawn by supplying steam 34 2 By indirectly heating the lean solution 112B of the absorption liquid, separating the coexisting materials coexisting. Recovery steam 112C heated by the third reclaimer. 31C recovery line L 104 through a, CO 2 is introduced into the bottom of the absorbing solution regeneration tower 113.
[0072]
　This withdrawal is branch line L 103 valve V provided 3 performed by opening and closing the. Note that the third reclaimer 31C, and provided with a heating unit 35 for indirectly heating the inside by steam 34 and supplies the reflux water 134 and an alkali agent 36a therein.
[0073]
　In this embodiment, CO according to the present embodiment 2 in the absorbent regenerator 113, withdrawing a portion of the lean solution 112B, reclaimer effluent 121 from the third reclaimer 31C for reproduction processing, nitrogen oxide absorption section 13 nitrogen oxides absorption liquid draw-out line L is introduced withdrawing a portion 12a of the nitrogen oxide absorbing solution 12 circulating through 5 reclaimer effluent supply line L connected to 21 are provided. Then, in the first reclaimer 31A, a portion 12a of the nitrogen oxide absorbing liquid (first absorbing liquid) 12, and heat regeneration process and reclaimer effluent 121 introduced.
[0074]
　This nitrogen oxide absorbing liquid (first absorbing liquid) 12 and CO 2 when using absorption liquid (second absorption liquid) 112 a tertiary amine of the common components, CO 2 CO absorption tower 111 2 has absorbed the rich solution 112A CO 2 during the regeneration process in the absorbing solution regeneration tower 113, CO 2 if discharging amine degradation product that accumulates in the absorption liquid 112 (contaminants) as a reclaimer effluent 121, while the reclaimer effluent 121 thong tertiary amine component is remained. Therefore, instead of discharging to the outside the tertiary amine component as the residue, is introduced into the first reclaimer 31A nitrogen oxides absorption liquid heating reproducing unit 23, recovered by vaporizing the tertiary amine component remaining here It is way. Thus, it is possible to reduce the emissions of the first reclaimer residue 37.
[0075]
　In this embodiment, nitrogen oxide absorbing liquid (first absorbing liquid) 12 and CO 2 that the absorption liquid of at least one common component as absorbent component of the (second absorption liquid) 112 (e.g., tertiary amine) preferable.
[0076]
　Further, emission gas line L from the first gas-liquid separator 33A 6 because during discharge gas 21 which is discharged through contains tertiary amine component vaporized, discharged gas line L 6 is installed in common absorber component return line L branched from the downstream side of the compressor (vacuum pump) 39 22 a provided to the tip CO 2 is connected to the vicinity of the bottom portion 113a of the absorbent regenerator 113.
[0077]
　As a result, gas of the tertiary amine component is reproduced CO 2 is introduced into the bottom portion 113a of the absorbent regenerator 113, wherein the CO with steam heating 2 is released, CO 2 absorbing liquid (second absorption liquid) It is reproduced as 112. Accordingly, CO 2 can reduce the absorption liquid new amount of supply from the outside of the (second absorption liquid) 112.
[0078]
　In this embodiment, by using the second exhaust gas treatment device 10B shown in FIG. 2, although regeneration processing, the third and fourth exhaust gas treatment device 10C shown in FIGS. 3 and 4, using a 10D exhaust gas the nitrogen oxides in 11 may be pretreated to remove.
[0079]
　6, other CO according to a fourth embodiment 2 is a schematic view of a recovery system. Note that the same members as in Example 1-3, and a description thereof will be omitted given the same reference numerals. As shown in FIG. 6, other CO according to Example 4 2 recovery device 100B, an exhaust gas introduction line L 1 has installed the gas introduction path switching unit 150 on the downstream side of the flue gas cooler 51. And this by switching the gas introduction path switching unit 150, the exhaust gas 11 is a bypass line L 31 from the exhaust gas cooling tower 51 through the CO 2 are to be introduced directly into the absorption tower 111.
[0080]
　The content of nitrogen oxides and carbon dioxide in the exhaust gas 11, while the content of nitrogen oxides is 1000ppm or less, the content of carbon dioxide several% to several tens% (for example 3-15% ) and it is enormous. Therefore, by measuring the nitrogen oxides in the exhaust gas 11, when the nitrogen oxides in the exhaust gas 11 is less than the threshold value, the nitrogen oxide absorbing portion 13 bypassing direct CO from the exhaust gas cooling tower 51 2 absorption tower We have introduced exhaust gas 11 to 111.
[0081]
　Specifically, in the case where a combustion apparatus boiler for low load operation, when the nitrogen oxides in the exhaust gas 11 is more and more the threshold introduces an exhaust gas 11 containing nitrogen oxides into nitrogen oxides absorbing portion 13. And nitrogen oxides removed by absorption with nitrogen oxide absorption section 13, the exhaust gas 11A removing the nitrogen oxides, CO 2 is introduced into the absorber 111, CO in the exhaust gas 11A 2 by absorbing and removing, cleaning gas so as to obtain the 11D.
[0082]
　On the other hand, when the boiler is less than the nitrogen oxides in the exhaust gas 11 is the threshold at normal operation, operates the gas introduction path switching unit 150, the exhaust gas 11 bypass line L 31 is introduced into, CO 2 only to the absorber 111 gas 11 introduces, CO in the exhaust gas 11 2 to be removed by absorption, may be obtained a purified gas 11D.
[0083]
　Thus, by operating the exhaust gas treatment apparatus only when the concentration of nitrogen oxides in the exhaust gas 11 high, it is possible to reduce the plant operating costs.
DESCRIPTION OF SYMBOLS
[0084]
　10A ~ 10D exhaust gas treatment apparatus
　11 flue gas
　12 of nitrogen oxides absorbing liquid (first absorbing
　liquid) 13 nitrogen oxide absorbing portion
　21 releasing gas
　22 of nitrogen oxides absorbing solution regeneration liquid (first
　regenerant) 23 nitrogen oxide absorption liquid heating reproducing section
　31A ~ 31C first to third reclaimer
　32A ~ 32C first to third discharge vapor
　33A ~ 33B first to second gas-liquid separator
　51 flue gas cooler
　100A ~ 100B CO 2 recovery apparatus
　112 CO 2 absorbing solution ( the second absorbing
　liquid) 111 CO 2 absorption tower
　113 CO 2 absorbing solution regeneration tower　

WE CLAIM

Discharged from the combustion device, and at least nitrogen oxides and carbon dioxide by introducing exhaust gas containing nitrogen oxides absorption unit for absorbing and removing nitrogen oxides in the flue gas by the nitrogen oxide absorbing liquid,
　nitrogen in the flue gas an exhaust gas discharge line for discharging the treated exhaust gas to remove oxides,
　connects the bottom and the top of said nitrogen oxide absorber, the nitrogen oxides absorption liquid circulation line for circulating said nitrogen oxide absorbing liquid,
　said nitrogen It is branched from the oxide absorption liquid circulation line, and the nitrogen oxide absorbing solution withdrawing nitrogen oxide absorbing liquid draw-out line the circulating
　heat regeneration process the nitrogen oxide absorbing liquid was withdrawn, at least monoxide a discharge gas containing nitrogen and carbon dioxide, and nitrogen oxides absorption liquid heating reproducing portion for obtaining a nitrogen oxide absorbing solution regeneration solution,
　the released gas from the nitrogen oxide absorbing solution heated regeneration unit, the waste gas A discharge gas line for introducing into the discharge line,
　comprising a nitrogen oxide absorbing solution regeneration liquid from the nitrogen oxide absorbing liquid thermal regeneration unit, and a regeneration liquid discharge line to be introduced into the nitrogen oxide absorption liquid circulation line exhaust gas treatment apparatus, characterized in that.
[Requested item 2]
　In claim 1,
　the exhaust gas processing device characterized by having an alkali supply unit for supplying an alkaline agent to the nitrogen oxide absorption solution heated regeneration unit.
[Requested item 3]
　According to claim 1 or 2,
　wherein the nitrogen oxide absorbing liquid heating reproducing unit,
　a first reclaimer for indirect heating by steam the nitrogen oxide absorbing liquid was withdrawn,
　the release steam from the first reclaimer provided release steam line that releases exhaust gas treatment apparatus characterized by comprising a first and a gas-liquid separator for gas-liquid separation and release gas and nitrogen oxide absorbing solution regeneration liquid from being released vapor.
[Requested item 4]
　According to claim 1 or 2,
　wherein the nitrogen oxide absorbing liquid heating reproducing unit,
　said withdrawn nitrogen oxides absorption liquid is nitrogen oxide absorbent regenerator having a reboiler for indirect heating by steam,
　the nitrogen oxides things absorbing liquid NO and CO from the top of the regenerator 2 is provided on the release steam line to release the release vapor containing, second to gas-liquid separation and release gas and nitrogen oxide absorbing solution regeneration liquid from the discharge vapor exhaust gas treatment apparatus characterized by comprising a gas-liquid separator.
[Requested item 5]
　In claim 4,
　the nitrogen oxide absorption regeneration liquid withdrawn from the bottom of the nitrogen oxide absorption regeneration tower was heated regeneration treatment, a discharge gas including at least nitrogen monoxide and carbon dioxide, nitrogen oxide absorbing solution regeneration exhaust gas treatment apparatus characterized by comprising a second reclaimer obtain a liquid.
[Requested item 6]
　In any one of claims 1 to 5,
　wherein the nitrogen oxide absorption liquid, an exhaust gas treatment apparatus, characterized in that an amine solution or an alkaline solution containing a tertiary amine.　
[Requested item 7]
　And one exhaust gas treatment device according to any one of claims 1 to 6,
　is introduced by the exhaust gas discharge line, said discharge gas mixed CO in the exhaust gas of 2 and CO 2 and absorbing liquid into contact CO and 2 to remove CO 2 and absorption tower,
　CO 2 rich solution that has absorbed CO regenerated by steam reboiler 2 and the absorbent regenerator,
　the CO 2 with withdrawing the rich solution from the absorber column, the CO 2 absorption liquid regenerator side a rich solution supply line to be introduced,
　the CO 2 CO reproduced by the absorbent regenerator 2 lean solution is dissipated the CO 2 with withdrawing from the absorption liquid regenerator, the CO 2 is introduced into the absorption tower, CO 2 and the lean-solution supply line to recycle as an absorbing solution,
　The withdrawn lean solution from the lean supply line, CO is characterized by comprising a third reclaimer to play lean solution, a 2 recovery apparatus.
[Requested item 8]
　According to claim 7,
　wherein the release branched from the gas line, a portion the CO of the discharge gas 2 CO and having a discharge gas branch line and introduced into the bottom of the absorbing solution regeneration tower 2 recovery apparatus.
[Requested item 9]
　According to claim 7 or 8,
　wherein the third with the bottom of the reclaimer withdrawn reclaimer effluent, the reclaimer effluent, having a reclaimer effluent inlet line for introducing the extraction liquid of the nitrogen oxide absorbing liquid CO and wherein the 2 recovery apparatus.
[Requested item 10]
　In any one of claims 7 to 9,
　the CO 2 and absorbing liquid, CO and at least one component is common absorbent component of the nitrogen oxide absorbing liquid 2 recovery apparatus.