JP4699039B2 - Exhaust gas treatment method and treatment apparatus - Google Patents

Description

  The present invention relates to an exhaust gas processing method and a processing apparatus for removing sulfur oxides and carbon dioxide contained in burned exhaust gas.

  In recent years, thermal power generation facilities and boiler facilities use a large amount of coal, heavy oil or ultra-heavy oil as fuel. From the viewpoint of preventing air pollution and cleaning the global environment, sulfur oxides, mainly sulfur dioxide, There is a problem of quantitative and concentration suppression regarding the release of nitrogen oxides, carbon dioxide and the like. Among these, sulfur oxides cause acid rain and may cause damage to human bodies, animals and plants. For this reason, conventionally, dry or wet processing methods have been proposed. For example, in a conventional flue gas desulfurization apparatus, a wet lime gypsum method in which gypsum is by-produced using limestone as an absorbent has become mainstream. On the other hand, with regard to carbon dioxide, from the standpoint of preventing global warming together with CFC and methane gas, for example, the suppression of emissions through the application of the PSA (pressure swing) method, the membrane absorption method, the reaction absorption method using basic compounds, etc. is studied. Has been.

  Moreover, the technique which implements a desulfurization process and a decarbonation process in two steps is proposed as the following patent document 1, for example. The "method for removing carbon dioxide and sulfur oxide in combustion exhaust gas" described in Patent Document 1 is a method of treating sulfur in desulfurization treatment gas by treating combustion exhaust gas in a wet lime-gypsum flue gas desulfurization process. After desulfurizing the oxide concentration in the range of 5 to 10 ppm, this desulfurized gas is contacted with an alkanolamine aqueous solution in a decarbonation step to treat carbon dioxide, thereby reducing the carbon dioxide concentration in the decarbonized gas to 1 ppm or less. To be decarboxylated.

Japanese Patent No. 3305001

  In the above-mentioned conventional “method for removing carbon dioxide and sulfur oxide in combustion exhaust gas”, after desulfurizing the combustion exhaust gas in the wet lime-gypsum flue gas desulfurization process, the desulfurization gas is removed by the decarbonation process. Is decarboxylated. When the combustion exhaust gas is desulfurized in this way and then shifted to decarbonation treatment at a high temperature, the amount of amine compound in the absorbing liquid that is scattered and accompanied by the exhaust gas increases, and the amine compound is wasted and operating costs are increased. There is a problem that increases. In addition, if the combustion exhaust gas is desulfurized and then cooled with a coolant and then decarboxylated, a cooling treatment waste liquid that cools the combustion exhaust gas is generated, and the processing cost of this cooling treatment waste liquid is generated. There is a problem of end.

  The present invention solves the above-described problems, and suppresses an increase in operation cost by cooling the exhaust gas, and also suppresses an increase in processing cost by effectively using the treatment waste liquid used for cooling. It is an object of the present invention to provide an exhaust gas processing method and a processing apparatus.

In order to achieve the above object, the exhaust gas treatment method of the invention of claim 1 is characterized in that an exhaust gas containing sulfur oxides and carbon dioxide is brought into contact with an absorption liquid containing a basic calcium compound, A desulfurization step for removing sulfur oxide; and the exhaust gas treated in the desulfurization step is brought into contact with a basic absorbent to further remove sulfur oxide in the exhaust gas, and above the exhaust gas, An advanced desulfurization gas cooling step that removes and collects the coolant mist accompanying the exhaust gas after cooling in contact with the coolant, and a desulfurization gas that removes carbon dioxide in the exhaust gas treated in the advanced desulfurization gas cooling step. And a carbonic acid process, wherein a cooling treatment effluent generated by condensation of moisture in the exhaust gas in the advanced desulfurization gas cooling process is supplied as makeup water to the desulfurization process.

In the exhaust gas treatment method according to the second aspect of the present invention, in the advanced desulfurization gas cooling step, the exhaust gas treated in the desulfurization step is brought into contact with a basic absorbent, and the concentration of sulfur oxide in the exhaust gas is reduced. The sulfur oxide is removed so as to be 5 ppm or less, and cooling is performed so that the temperature of the exhaust gas is 50 ° C. or less.

The processing method of the exhaust gas of the invention of claim 3, wherein as the storage amount of the cooling liquid storing highly desulfurized gas cooling step is a predetermined amount, adjusting the supply amount of the makeup water supplied to the desulfurization step It is characterized by that.

The processing method of the exhaust gas of the invention of claim 4, together with the storage amount of the cooling liquid stored in the high desulfurizing gas cooling process becomes a certain amount, the supply amount of the makeup water supplied to the desulfurization step and a predetermined amount so that is characterized by adjusting the gas cooling efficiency in the highly desulfurized gas cooling step.
In the claims 5 processing method of the exhaust gas of the invention, in the highly desulfurized gas cooling step, the moisture in the exhaust gas is generated by mixing the cooled liquid reserved the condensed water obtained by condensing downward The cooling treatment effluent is supplied as makeup water to the desulfurization step.

The exhaust gas treatment apparatus of the invention of claim 6 is a desulfurization means for removing the sulfur oxide in the exhaust gas by bringing the exhaust gas containing sulfur oxide and carbon dioxide into contact with an absorbent containing a basic calcium compound. And an advanced desulfurization section for further removing sulfur oxides in the exhaust gas by bringing the exhaust gas treated by the desulfurization means into contact with a basic absorbing liquid, and contacting the exhaust gas with a cooling liquid thereabove. Advanced desulfurization gas cooling means having a cooling section for cooling and a demister for removing and recovering coolant mist accompanying the exhaust gas above the cooling section, and removing carbon dioxide in the exhaust gas treated by the advanced desulfurization gas cooling means And a replenishment water supply means for supplying the desulfurization means with a cooling treatment effluent generated by condensation of moisture in the exhaust gas by the advanced desulfurization gas cooling means. It is an feature.

In the exhaust gas treatment apparatus of the invention of claim 7, the advanced desulfurization gas cooling means brings the exhaust gas treated by the desulfurization means into contact with a basic absorbent so that the sulfur oxide concentration in the exhaust gas is reduced. The sulfur oxide is removed so as to be 5 ppm or less, and cooling is performed so that the temperature of the exhaust gas is 50 ° C. or less.

Wherein in the processing device for the exhaust gas of the invention of claim 8, the cooling liquid quantity measuring means for measuring the amount of stored cooling liquid stored in the highly desulfurized gas cooling means, based on the measurement result of the cooling liquid quantity measuring means Control means for adjusting the supply amount of the makeup water to the desulfurization means by controlling the makeup water supply means so that the storage amount of the coolant becomes a constant amount is provided.

Wherein the processing device for the exhaust gas of the invention of claim 9, the cooling liquid quantity measuring means for measuring the amount of stored cooling liquid stored in the highly desulfurized gas cooling means, based on the measurement result of the cooling liquid quantity measuring means supply amount of the makeup water supplied to the desulfurization unit with the storage amount of the cooling liquid becomes constant amount by controlling the high desulfurizing gas cooling means so that the predetermined amount is provided a control means for adjusting the gas cooling efficiency It is characterized by that.
In the processing apparatus of the exhaust gas of the invention of claim 10, wherein the highly desulfurized gas cooling means comprises a cooling liquid reservoir for storing a coolant downward, the condensed water moisture in the exhaust gas is obtained by condensing Is supplied to the desulfurization means as make-up water.

According to the exhaust gas treatment method of the first aspect of the present invention, the exhaust gas containing sulfur oxide and carbon dioxide is brought into contact with an absorbing solution containing a basic calcium compound to remove the sulfur oxide and subjected to desulfurization treatment. After the exhaust gas is brought into contact with the basic absorption liquid to further remove sulfur oxides and the exhaust gas is brought into contact with the cooling liquid at the upper side and cooled, the cooling liquid mist accompanying the exhaust gas is removed and recovered. While removing the carbon dioxide in the exhaust gas that has been cooled, advanced desulfurization and cooling process wastewater generated by condensation of moisture in the exhaust gas is supplied as makeup water to the desulfurization process. In addition, by cooling the exhaust gas and then decarboxylating it, waste of the absorbent for treating the carbon dioxide can be prevented and an increase in operating cost can be suppressed, and the treatment used for cooling the exhaust gas can be suppressed. Draining it is possible to suppress an increase in processing cost by effectively using the desulfurization treatment, in this case, it is possible to improve the desulfurization performance by basic absorbing liquid contained in the processing effluent.

According to the exhaust gas treatment method of the invention of claim 2 , in the advanced desulfurization gas cooling step, the concentration of sulfur oxide in the exhaust gas is set to 5 ppm or less, and the temperature of the exhaust gas is set to 50 ° C. or less. Accurate desulfurization and decarbonation are possible.

According to the exhaust gas processing method of the invention of claim 3, the supply amount of makeup water supplied to the desulfurization process is adjusted so that the storage amount of the coolant stored in the advanced desulfurization gas cooling process becomes a constant amount. Therefore, it is possible to reliably supply surplus process waste liquid as make-up water to the desulfurization process while maintaining high cooling efficiency in the advanced desulfurization gas cooling process.

According to the exhaust gas processing method of the fourth aspect of the invention, the storage amount of the coolant stored in the advanced desulfurization gas cooling step is a constant amount, and the supply amount of makeup water supplied to the desulfurization step is a predetermined amount. As described above, since the gas cooling efficiency in the advanced desulfurization gas cooling process is adjusted, the cooling efficiency in the advanced desulfurization gas cooling process can be maintained at a high efficiency, and moisture in the exhaust gas is condensed in the cooling process. Thus, the amount of the cooling treatment effluent generated and the amount of make-up water necessary for the desulfurization step are substantially the same, so that the excess treatment effluent can be eliminated.
According to the exhaust gas treatment method of the fifth aspect of the invention, in the advanced desulfurization gas cooling step, the condensed water obtained by condensing the moisture in the exhaust gas is mixed with the coolant stored below and generated. Since the cooling treatment effluent is supplied as makeup water to the desulfurization step, the treatment effluent used for cooling the exhaust gas can be effectively used for the desulfurization treatment.

According to the exhaust gas treatment apparatus of the invention of claim 6 , the desulfurization means for removing the sulfur oxide by bringing the exhaust gas containing sulfur oxide and carbon dioxide into contact with the absorbent containing the basic calcium compound, and desulfurization The treated exhaust gas is brought into contact with the basic absorption liquid to further remove sulfur oxides, and the upper desulfurization section above and the cooling section in which exhaust gas is brought into contact with the cooling liquid to cool, and the exhaust gas is accompanied therewith. Advanced desulfurization gas cooling means having a demister for removing and recovering the coolant mist, decarbonation means for removing carbon dioxide in exhaust gas that has been subjected to advanced desulfurization and cooling treatment, and water in the exhaust gas by cooling. Since the replenishing water supply means for supplying the cooling treatment effluent generated by condensation as replenishing water to the desulfurization means is provided, the exhaust gas is cooled and then decarbonated to absorb carbon dioxide. It is possible to prevent waste of liquid and suppress increase in operating cost, and it is possible to suppress increase in processing cost by effectively using treatment waste liquid used for cooling exhaust gas for desulfurization treatment. In this case, the desulfurization performance can be improved by containing the basic absorbent in the treatment waste liquid.

According to the exhaust gas treatment apparatus of the seventh aspect of the invention, the advanced desulfurization gas cooling means makes the sulfur oxide concentration in the exhaust gas 5 ppm or less and the temperature of the exhaust gas 50 ° C. or less. Desulfurization treatment and decarbonation treatment are possible.

According to the exhaust gas treatment apparatus of the eighth aspect of the present invention, the coolant amount measuring means for measuring the amount of coolant stored in the advanced desulfurization gas cooling means is provided, and the control means has a constant amount of coolant stored. since controls the replenishing water supplying means so that the amount to adjust the supply amount of the makeup water to the desulfurization unit, while maintaining cooling efficiency in high desulfurization gas cooling process with high efficiency, the process effluent a surplus It can be reliably supplied to the desulfurization process as makeup water.

According to the exhaust gas treatment apparatus of the ninth aspect of the present invention, there is provided the coolant amount measuring means for measuring the amount of coolant stored in the advanced desulfurization gas cooling means, and the control means has a constant coolant storage amount. The gas cooling efficiency is adjusted by controlling the advanced desulfurization gas cooling means so that the supply amount of makeup water supplied to the desulfurization means becomes a predetermined amount, so that the cooling efficiency in the advanced desulfurization gas cooling process is made highly efficient. In addition, the amount of cooling process waste liquid generated by condensation of moisture in the exhaust gas during the cooling process and the amount of make-up water required for the desulfurization process are almost the same amount, so that the excess process waste The liquid can be lost.
According to the exhaust gas treatment device of the invention of claim 10, as the advanced desulfurization gas cooling means, a cooling liquid storage part for storing the cooling liquid is provided below, and condensed water obtained by condensing moisture in the exhaust gas is provided. Since the cooling treatment effluent generated by mixing with the cooling liquid in the cooling liquid reservoir is supplied to the desulfurization means as make-up water, the treatment effluent used for cooling the exhaust gas can be effectively used for the desulfurization treatment. .

  Exemplary embodiments of a method and an apparatus for treating exhaust gas according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic configuration diagram illustrating an exhaust gas processing apparatus according to Embodiment 1 of the present invention, FIG. 2 is a schematic diagram illustrating a gas cooling processing apparatus in the exhaust gas processing apparatus of Embodiment 1, and FIG. 1 is a schematic diagram illustrating a decarbonation processing apparatus in an exhaust gas processing apparatus according to Embodiment 1. FIG.

  As shown in FIG. 1, the exhaust gas treatment apparatus of the first embodiment includes a desulfurization treatment device (desulfurization means) 12 that desulfurizes exhaust gas discharged from a boiler 11 that uses coal or the like as fuel, and a desulfurization treatment. A gas cooling processing device (gas cooling means) 13 that cools the exhaust gas processed by the apparatus 12 and a decarbonation processing device (carbon dioxide means) 14 that decarboxylates the exhaust gas processed by the gas cooling processing device 13. And a chimney 15 for discharging the purified exhaust gas.

  The exhaust gas exhausted from the boiler 11 contains sulfur oxides and carbon dioxide, and the desulfurization treatment device 12 makes the exhaust gas contact with the basic absorbent so that the sulfur oxides in the exhaust gas are brought into contact with each other. Is absorbed and removed (desulfurization process). In this case, the basic absorbing liquid is a basic calcium compound, and specifically, calcium carbonate, calcium hydroxide, and calcium oxide can be used. The basic absorption liquid may be one of these compounds or a mixture of two or more compounds, and is usually used as a suspension. In the desulfurization treatment device 12, the basic absorbent that has contacted the exhaust gas and absorbed the sulfur oxide is sent to the separation and recovery device 16, and the sulfur oxide absorbed in the basic absorbent is gypsum. Separated and recovered.

  The gas cooling treatment device 13 cools the exhaust gas desulfurized by the desulfurization treatment device 12 (gas cooling step). More specifically, in this gas cooling processing apparatus 13, as shown in FIG. 2, the gas cooling tower 21 is provided with a cooling liquid storage section 22 at the lower part, and the desulfurization processing apparatus 12 is above the cooling liquid storage section 22. A gas introduction line 23 for introducing the exhaust gas desulfurized in the above is connected, and a gas discharge line 24 for discharging the cooled exhaust gas is connected to the upper end of the gas cooling tower 21. And the gas cooling tower 21 is provided with the gas cooling part 25 and the gas cooling part demister 26 in order from the bottom. The gas cooling tower 21 is provided with a coolant circulation line 27 for supplying the coolant in the coolant reservoir 22 from above the gas cooler 25. The coolant circulation line 27 includes: A coolant pump 28 and a heat exchanger 29 are provided.

  Therefore, in the gas cooling processing device 13, the exhaust gas desulfurized by the desulfurization processing device 12 is introduced into the lower portion of the gas cooling tower 21 from the gas introduction line 23, while the coolant in the coolant storage unit 22 is cooled. The liquid pump 28 passes through the coolant circulation line 27, is cooled by the heat exchanger 29, and then is supplied from above the gas cooling unit 25. Then, in this gas cooling part 25, it cools because exhaust gas and a cooling liquid contact, and can make gas temperature 50 degrees C or less. The coolant mist accompanying the exhaust gas is removed and collected by the gas cooling unit demister 26 and stored in the coolant storage unit 22.

  The decarbonation treatment device 14 brings the exhaust gas cooled by the gas cooling treatment device 13 into contact with a decarboxylation absorbent containing a basic amine compound, thereby removing carbon dioxide and remaining sulfur oxide in the exhaust gas. It is to be removed (decarboxylation step). In this case, examples of the basic amine compound include monoethanolamine, alcoholic hydroxyl group-containing primary amines such as 2-amino-2-methyl-1-propanol, diethanolamine, 2-methylaminoethanol, and 2-ethylamino. Alcoholic hydroxyl group-containing secondary amines such as ethanol, triethanolamine, N-methyldiethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol and other alcoholic hydroxyl group-containing tertiary amines, ethylenediamine, triethylenediamine, diethylenetriamine, etc. Polyethylene polyamines, piperazines, piperidines, cyclic amines such as pyrrolidines, polyamines such as xylylenediamine, and amino acids such as methylamilycarponic acid can be used. .

  The decarboxylation absorbent may be one of these compounds or a mixture of two or more compounds, and the basic amine compound is usually used as an aqueous solution of 10 to 70% by weight. In addition, a carbon dioxide absorption accelerator and a corrosion inhibitor can be added to the decarboxylation absorbent, and methanol, polyethylene glycol, sulfolane, and the like can be added as other media.

  More specifically, as shown in FIG. 3, in the decarbonation processing apparatus 14, the absorption tower 31 is provided with an absorption liquid storage section 32 at the lower portion, and the cooling processing apparatus 13 cools the absorption liquid storage section 32 above the absorption liquid storage section 32. A gas introduction line 33 for introducing the treated exhaust gas is connected, and a gas discharge line 34 for discharging the treated exhaust gas decarboxylated is connected to the upper end portion of the absorption tower 31. And in the absorption tower 31, the carbon dioxide absorption part 35, the carbon dioxide absorption part demister 36, the water washing part 37, and the water washing part demister 38 are sequentially provided in the inside from the downward direction. On the other hand, the regeneration tower 39 is provided with an absorption liquid storage section 40 at the bottom, and a recovery section 41 and a concentration section 42 are provided in order from below.

  The absorption tower 31 is provided with an absorption liquid regeneration line 43 for supplying the decarboxylated absorption liquid in the absorption liquid storage section 32 between the recovery section 41 and the concentration section 42 in the regeneration tower 39, and this absorption liquid regeneration line. 43 is provided with a heat exchanger 44. Further, the absorption tower 31 is provided with a cleaning liquid supply line 45 that takes out the cleaning liquid from between the carbon dioxide absorption section demister 36 and the water washing section 37 and supplies it between the water washing section 37 and the water washing section demister 38. A heat exchanger 46 is provided at 45.

  On the other hand, in the regeneration tower 39, the decarboxylated absorbent in the absorbent reservoir 40 is regenerated by the reboiler 47, and the carbon dioxide absorber 35 and the carbon dioxide absorber demister 36 in the absorber 31 are passed through the heat exchangers 44 and 48. An absorption liquid supply line 49 is provided in between. The regeneration tower 39 has a circulation line 51 that sends the decarboxylated absorbent in the absorbent reservoir 40 to the reclaimer 50 and returns the decarboxylated absorbent after the reclaiming operation to the absorbent reservoir 40 with a basic sodium compound. Is provided. Further, a gas discharge line 53 is connected to the upper end of the regeneration tower 39 to discharge the decarbonized exhaust gas and send it to the carbon dioxide separator 52, and a condenser 54 is provided in the gas discharge line 53. Yes. The cleaning liquid supply line 45 is provided with a branch line 55 that branches in the middle and reaches the upper end of the regeneration tower 39. In the branch line 55, water separated by the carbon dioxide separator 52 is used as reflux water. A reflux water supply line 56 for supplying the absorption tower 31 or the regeneration tower 39 is connected.

  Therefore, in the decarbonation processing device 14, the exhaust gas cooled in the cooling processing device 13 is introduced from the gas introduction line 33 to the lower portion of the absorption tower 31, while the decarbonized absorption liquid is absorbed by the absorption liquid supply line 49. Supplied from above the carbon absorber 35. Then, in the carbon dioxide absorption part 35, the carbon dioxide and the remaining sulfur oxide in the exhaust gas can be removed by contacting the exhaust gas with the decarboxylation absorbent containing the basic amine compound. The mist of the decarboxylated absorbent accompanying the exhaust gas is removed and recovered by the carbon dioxide absorbent demister 36 and stored in the absorbent reservoir 32. Then, the decarbonized exhaust gas is washed with a water washing section 37, and mist is removed and collected by a water washing section demister 38, and then discharged from the absorption tower 31 through a gas discharge line 34, and the chimney 15 (see FIG. 1). Through the atmosphere. On the other hand, the decarboxylated absorbent (load absorbent) collected in the absorbent reservoir 32 is sent to the regeneration tower 39 through the absorbent regeneration line 43 and heated by steam in the reboiler 47 to dissipate carbon dioxide. Regenerated and supplied to the absorption tower 31 through the absorption liquid supply line 49.

  Further, the decarboxylated absorbent (load absorbent) in the absorbent reservoir 40 of the regeneration tower 39 has the absorbed sulfur oxide remaining as sulfate or sulfite, and is removed using the reclaimer 50. That is, in the reclaimer 50, after adding a basic sodium compound to the load absorbent remaining as sulfate or sulfite, the amine compound is distilled off by heating with steam and returned to the absorbent reservoir 40. On the other hand, the sulfate or sulfite separated from the amine compound is discharged from the reclaimer 50 as sludge which is sodium sulfate or a mixture of sodium sulfate and sodium sulfite.

  The carbon dioxide diffused by the recovery unit 41 of the regeneration tower 39 is washed by the concentrating unit 42, cooled by the condenser 54 through the gas discharge line 53, and then sent to the carbon dioxide separator 52, where Then, it is separated into high-purity carbon dioxide and water, and the water is returned to the absorption tower 31 or the regeneration tower 39.

  Thereafter, the exhaust gas from which the carbon dioxide and the remaining sulfur oxide have been removed by the decarboxylation device 14 is released or sent to the next necessary step.

  By the way, in the desulfurization processing apparatus 12 mentioned above, the sulfur oxide in this exhaust gas is absorbed and removed by making the exhaust gas from the boiler 11 contact a basic absorption liquid, but this desulfurization process. Sometimes, the moisture in the basic absorbent is evaporated by the heat of the exhaust gas. For this reason, since it is necessary to maintain the basic absorbing solution at a predetermined concentration, a predetermined amount of water needs to be replenished at all times. On the other hand, in the gas cooling processing device 13, while the cooling liquid is circulated by the cooling liquid circulation line 27, the cooling liquid is brought into contact with the exhaust gas in the gas cooling unit 25 to cool it. The moisture in the gas condenses and the coolant increases.

  Therefore, in the first embodiment, moisture (cooling waste liquid) generated during the exhaust gas cooling process in the gas cooling processing device 13 is used to remove the moisture that is insufficient during the exhaust gas desulfurization processing in the desulfurization processing device 12. A makeup water supply means for supplying the makeup water is provided.

  That is, as shown in FIG. 1 and FIG. 2, the coolant circulation line 27 in the gas cooling processor 13 is branched from the downstream side of the coolant pump 28, and a coolant discharge line 61 is provided. A flow rate adjustment valve 62 is provided in the coolant extraction line 61 and is connected to the desulfurization processing apparatus 12. The coolant pump 28 and the flow rate adjustment valve 62 can be driven and controlled by the control device 63. Further, the coolant storage unit 22 of the gas cooling processing device 13 is provided with a liquid level sensor (cooling fluid amount measuring means) 64 for measuring the storage amount of the coolant stored therein, and the measurement result is controlled by the control device. 63 is output.

  Therefore, the control device 63 receives the measurement result of the liquid level sensor 64 and always knows the liquid level height of the cooling liquid in the cooling liquid storage unit 22, that is, the amount of cooling liquid stored in the cooling liquid storage unit 22. Then, the drive torque of the coolant pump 28 and the opening degree of the flow rate adjustment valve 62 are controlled so that the amount of coolant stored becomes a constant amount, and the desulfurization processing device is passed from the gas cooling processing device 13 through the coolant extraction line 61. The supply amount of the replenishing water (cooling treatment waste liquid) supplied to the water 12 can be adjusted.

  That is, in the gas cooling processing device 13, when cooling is performed by bringing the coolant into contact with the exhaust gas, moisture in the exhaust gas is condensed and mixed into the coolant, so that the coolant stored in the coolant storage unit 22 The amount of storage increases and the liquid level rises. Then, the control device 63 confirms the rise in the coolant level in the coolant reservoir 22 from the fluid level sensor 64, and controls and increases the driving torque of the coolant pump 28 and the opening of the flow rate adjustment valve 62. Only the amount of the cooling liquid is supplied to the desulfurization treatment apparatus 12 as make-up water. In the desulfurization treatment device 12, the moisture in the basic absorption solution evaporates due to the heat of the exhaust gas during the desulfurization treatment in which the basic absorption solution is brought into contact with the exhaust gas to absorb sulfur oxide. The deficiency is replenished by the replenishing water supplied through the coolant discharge line 61.

  In this case, in the desulfurization processing device 12, the moisture in the basic absorbent is evaporated by heat of the exhaust gas and mixed into the exhaust gas, and the exhaust gas mixed with this moisture is sent to the gas cooling processing device 13, where By cooling in contact with the coolant, moisture in the exhaust gas is condensed and the coolant increases. Therefore, the evaporation amount (insufficient amount) of water in the basic absorption liquid in the desulfurization treatment device 12 and the moisture condensation amount (replenishment amount) in the gas cooling treatment device 13 are substantially the same, and the makeup water from the outside is It becomes unnecessary.

Here, the exhaust gas processing method and the processing conditions and results of the processing apparatus of Example 1 will be described.
Operating conditions:
Exhaust gas flow rate at the inlet of the desulfurization processing unit 12 ... 200 m ³ N / h
Exhaust gas temperature at the inlet of the desulfurization treatment unit 12 ... 98 ° C
Moisture content of exhaust gas at the inlet of the desulfurization treatment unit 12 8.3 vol%
Exhaust gas temperature at the outlet of the desulfurization processing unit 12 ... 49 ° C
Exhaust gas temperature at the outlet of the gas cooling processor 13 ... 40 ° C
Driving results:
Moisture condensation amount in gas cooling processing unit 13 ... 8.0 kg / h
Moisture deficiency in desulfurization processing unit 12 ............ 7.9kg / h
Accordingly, out of the water condensation amount of 8.0 kg / h in the gas cooling processing device 13, by supplying makeup water 7.9 kg / h to the desulfurization processing device 12, makeup water is supplied to the desulfurization processing device 12 from another line. There is no need to supply.

  Thus, in the exhaust gas treatment method and treatment apparatus of Example 1, the desulfurization treatment apparatus 12 that removes sulfur oxide by bringing the exhaust gas into contact with the basic absorbent, and the desulfurized exhaust gas Gas cooling treatment device 13 for cooling, decarbonation treatment device 14 for removing carbon dioxide in the cooled exhaust gas, and cooling treatment waste liquid generated by condensation of water in the exhaust gas by cooling. A coolant discharge line 61 is provided as a makeup water supply means for supplying the desulfurization treatment device 12 as makeup water.

  Therefore, by cooling the exhaust gas and then performing the decarbonation treatment, it is possible to prevent the waste of the absorbing liquid for treating the carbon dioxide in the decarbonation treatment apparatus and to suppress an increase in the operating cost. By supplying the cooling liquid, which has increased due to condensation of moisture in the exhaust gas in the cooling processing device 13, as depletion water to the desulfurization processing device 12, the shortage of moisture in the basic absorption liquid evaporated by the heat of the exhaust gas is reduced. Replenishment water from the outside can be made unnecessary, and an increase in processing cost can be suppressed by effectively using the cooling processing waste liquid.

  Further, a liquid level sensor 64 for measuring the amount of stored coolant is provided in the coolant storage unit 22 of the gas cooling processing device 13, and the control device 63 receives the measurement result of the liquid level sensor 64 and receives the coolant storage unit 22. The coolant level in the coolant, that is, the amount of coolant stored in the coolant reservoir 22, and the drive torque and flow rate adjustment of the coolant pump 28 so that the amount of coolant stored is constant. The opening amount of the valve 62 is controlled, and the supply amount of makeup water supplied from the gas cooling processing device 13 to the desulfurization processing device 12 is adjusted.

  Therefore, after ensuring the circulation amount of the cooling liquid in the gas cooling processing apparatus 13, the surplus cooling liquid is supplied to the desulfurization processing apparatus 12, while maintaining the cooling efficiency in the gas cooling processing apparatus 13 with high efficiency. The surplus processing waste liquid can be reliably supplied to the desulfurization processing apparatus 12 as make-up water.

  FIG. 4 is a schematic configuration diagram illustrating an exhaust gas processing apparatus according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, the exhaust gas treatment device of the second embodiment cools the exhaust gas treated by the desulfurization treatment device 12 and the desulfurization treatment device 12 that performs desulfurization treatment on the exhaust gas discharged from the boiler 11. Gas cooling treatment device 13, decarbonation treatment device 14 for decarboxylation treatment of the exhaust gas treated by gas cooling treatment device 13, and chimney 15 for discharging the purified exhaust gas. .

  In the second embodiment, as in the first embodiment, moisture (cooling wastewater) generated during the exhaust gas cooling process in the gas cooling processing apparatus 13 is removed from the exhaust gas by the desulfurization processing apparatus 12. A replenishing water supply means is provided for supplying replenishing water that is insufficient at the time of processing.

  That is, as shown in FIG. 1, the coolant circulation line 27 in the gas cooling processor 13 is branched from the downstream side of the coolant pump 28, and a coolant discharge line 61 is provided. A flow rate adjustment valve 62 is provided in the outlet line 61 and is connected to the desulfurization processing apparatus 12. The coolant pump 28 and the flow rate adjustment valve 62 can be driven and controlled by the control device 63. In addition, the gas cooling processing device 13 is provided with a liquid level sensor 64 for measuring the amount of coolant stored in the coolant storage unit 22 and a gas temperature sensor 65 for measuring the exhaust gas temperature after cooling. The measurement result is output to the control device 63. Further, the desulfurization treatment device 12 is provided with a moisture deficiency sensor 66 for measuring the deficiency of moisture in the basic absorbent evaporated by the heat of the exhaust gas, and outputs the measurement result to the control device 63. Yes.

  Therefore, the control device 63 receives the measurement result of the liquid level sensor 64 and always knows the liquid level height of the cooling liquid in the cooling liquid storage unit 22, that is, the amount of cooling liquid stored in the cooling liquid storage unit 22. Then, the drive torque of the coolant pump 28 and the opening degree of the flow rate adjustment valve 62 are controlled so that the amount of coolant stored becomes a constant amount, and the desulfurization processing device is passed from the gas cooling processing device 13 through the coolant extraction line 61. The supply amount of the replenishing water (cooling treatment waste liquid) supplied to the water 12 can be adjusted. Further, the control device 63 receives the measurement result of the moisture shortage sensor 66 and supplies the coolant circulation line 27 so that the amount of makeup water supplied from the gas cooling treatment device 13 to the desulfurization treatment device 12 becomes a predetermined amount corresponding to the shortage amount. The cooling efficiency of the heat exchanger 29 provided in (see FIG. 2) can be controlled.

  That is, in the gas cooling processing device 13, when cooling is performed by bringing the coolant into contact with the exhaust gas, moisture in the exhaust gas is condensed and mixed into the coolant, so that the coolant stored in the coolant storage unit 22 The amount of storage increases and the liquid level rises. On the other hand, in the desulfurization treatment device 12, when desulfurization is performed by bringing the desulfurization absorption liquid into contact with the exhaust gas, the moisture in the basic absorption liquid evaporates due to the heat of the exhaust gas and becomes insufficient. Then, the control device 63 receives the measurement results of the liquid level sensor 64 and the water shortage sensor 66, and increases the amount of cooling liquid generated in the gas cooling processing device 13 and the shortage of water shortage in the desulfurization processing device 12. Are controlled to control the cooling efficiency of the heat exchanger 29 in the gas cooling processing device 13.

  Specifically, when the amount of water condensation generated in the gas cooling treatment device 13 is small compared to the shortage of water shortage in the desulfurization treatment device 12, the supply amount of the cooling medium in the heat exchanger 29 is increased. By increasing the cooling efficiency, the amount of water to be condensed is increased. On the other hand, when there is a large increase in the amount of moisture condensed in the gas cooling treatment device 13 relative to the lack of moisture in the desulfurization treatment device 12, the cooling medium supply amount in the heat exchanger 29 is lowered to lower the cooling efficiency. By doing so, the amount of moisture that condenses is reduced. In this case, the control device 63 controls the cooling efficiency of the heat exchanger 29 so that the exhaust gas temperature after cooling measured by the gas temperature sensor 65 does not exceed a predetermined temperature (for example, 50 ° C.), and the cooling liquid By controlling the driving torque of the pump 28 and the opening degree of the flow rate adjusting valve 62, only the necessary replenishing water amount is replenished to the desulfurization processing device 12 from the gas cooling processing device 13 through the coolant discharge line 61.

Here, the exhaust gas processing method and the processing apparatus operating conditions and results of Example 2 will be described.
Operating conditions:
Exhaust gas flow rate at the inlet of the desulfurization processing unit 12 ... 200 m ³ N / h
Exhaust gas temperature at the inlet of the desulfurization treatment unit 12 ... 98 ° C
Moisture content of exhaust gas at the inlet of the desulfurization treatment unit 12 8.3 vol%
Exhaust gas temperature at the outlet of the desulfurization processing unit 12 ... 49 ° C
Exhaust gas temperature at the outlet of the gas cooling processor 13 ... 40.2 ° C
Driving results:
Moisture condensation amount in the gas cooling processing unit 13 ... 7.9 kg / h
Moisture deficiency in desulfurization processing unit 12 ............ 7.9kg / h
Accordingly, the amount of water condensation in the gas cooling processing device 13 is 7.9 kg / h and the amount of water shortage in the desulfurization processing device 12 is 7.9 kg / h, so that the cooling waste liquid or desulfurization processing device to be discarded. There is no need for makeup water to be replenished from another line.

  As described above, in the exhaust gas processing method and processing apparatus according to the second embodiment, the cooling treatment effluent generated by condensation of moisture in the exhaust gas in the gas cooling processing device 13 is supplied to the desulfurization processing device 12 as makeup water. A coolant extraction line 61 to be supplied is provided, and a liquid level sensor 64 that measures the amount of coolant stored in the coolant storage unit 22 of the gas cooling processor 13 and the desulfurization processor 12 evaporates due to the heat of the exhaust gas. A water shortage sensor 66 for measuring the water shortage in the basic absorbent is provided, and the controller 63 measures the liquid level height of the coolant measured by the liquid level sensor 64 and the water shortage sensor 66. The cooling efficiency of the heat exchanger 29 is controlled so that the shortage amount of makeup water is grasped and the amount of coolant stored is constant and the amount of makeup water is a predetermined amount.

  Therefore, by supplying the cooling liquid, which has increased due to condensation of moisture in the exhaust gas in the gas cooling processing device 13, as supplementary water to the desulfurization processing device 12, the moisture in the basic absorption liquid evaporated by the heat of the exhaust gas can be obtained. The shortage is replenished, and an increase in processing cost can be suppressed by effectively using the cooling processing waste liquid. In this case, the amount of coolant stored is constant, the amount of deficiency in the desulfurization treatment and the amount of make-up water are the same, so external make-up water can be made unnecessary and surplus Therefore, it is not necessary to discard the processing waste liquid, which can prevent an increase in operating cost and processing cost.

  FIG. 5 is a schematic configuration diagram illustrating an exhaust gas processing apparatus according to a third embodiment of the present invention, and FIG. 6 is a schematic diagram illustrating an advanced desulfurization gas cooling processing apparatus in the exhaust gas processing apparatus according to the third embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 5, the exhaust gas treatment apparatus of the third embodiment includes a desulfurization treatment device 12 that desulfurizes the exhaust gas discharged from the boiler 11, and the exhaust gas treated by the desulfurization treatment device 12 as a base. The advanced desulfurization gas cooling processing device 17 for further removing sulfur oxides in the exhaust gas by being brought into contact with the oxidizing absorbent and cooling the exhaust gas, and the exhaust gas treated by the advanced desulfurization gas cooling processing device 17 is removed. It comprises a decarbonation device 14 that performs a carbonic acid treatment, and a chimney 15 that discharges the exhaust gas that has been purified.

  The advanced desulfurization gas cooling treatment device 17 makes the sulfur oxide concentration 5 ppm or less, preferably 1 ppm or less by bringing the exhaust gas subjected to the desulfurization treatment into contact with the basic absorbent and further removing sulfur oxide in the exhaust gas. Is subjected to advanced desulfurization treatment. When the concentration of sulfur oxide in the exhaust gas exceeds 5 ppm, sulfur oxide accumulates in the decarboxylation absorbent used in the decarboxylation apparatus 14, and the frequency of reclaiming the decarboxylation absorbent (load absorbent) increases. End up.

  As the basic absorption liquid, for example, an absorption liquid containing one basic compound or a mixture of two or more compounds of calcium carbonate, calcium hydroxide, magnesium hydroxide, sodium hydroxide and the like can be used. . Among these, it is particularly preferable to use an absorbent containing a basic sodium compound such as sodium hydroxide or sodium carbonate from the viewpoint of desulfurization performance. Moreover, a basic compound is normally used as a 0.1-30 weight% aqueous solution.

  Further, the advanced desulfurization gas cooling treatment device 17 cools the exhaust gas subjected to the advanced desulfurization treatment to 50 ° C. or less, preferably 45 ° C. or less, more preferably 30 to 45 ° C. When the temperature of the exhaust gas exceeds 50 ° C., the amount of the amine compound in the decarbonation absorption liquid accompanying the exhaust gas increases in the decarbonation treatment device 14, and this amine compound is consumed wastefully, resulting in an operating cost and the like. It will increase. On the other hand, if it is less than 30 degreeC, cooling cost will increase.

  More specifically, in the advanced desulfurization gas cooling processing device 17, as shown in FIG. 6, the advanced desulfurization gas cooling tower 71 is provided with an absorbing liquid storage part 72 at the lower part, and desulfurization is provided above the cooling liquid storage part 72. A gas introduction line 73 for introducing the exhaust gas desulfurized by the processing apparatus 12 is connected to the upper end of the advanced desulfurization gas cooling tower 71, and a gas exhaust line 74 for exhausting the exhaust gas that has been highly desulfurized and cooled is connected. ing. In the advanced desulfurization gas cooling tower 71, an advanced desulfurization section 75, an advanced desulfurization section demister 76, a gas cooling section 77, and a gas cooling section demister 78 are provided in this order from below.

  The advanced desulfurization gas cooling tower 71 is provided with an absorption liquid circulation line 79 for supplying the basic absorption liquid in the absorption liquid storage part 72 from above the advanced desulfurization part 75. Is provided with an absorption liquid pump 80. The absorption liquid circulation line 79 is connected to a supply liquid addition line 81 for replenishing and adding a supply liquid containing a basic compound, and an absorption liquid extraction line 82 for extracting a part of the basic absorption liquid. Further, the advanced desulfurization gas cooling tower 71 is provided with a cooling liquid circulation line 83 for supplying a basic absorption liquid as a cooling liquid from the bottom to the top of the gas cooling section 77. Are provided with a heat exchanger 84 and a coolant circulation pump 85. A cooling liquid extraction line 86 for extracting a part of the basic absorption liquid from the cooling liquid circulation line 83 and supplying it to the absorption liquid circulation line 79 is provided. The cooling liquid extraction line 86 includes a cooling liquid pump 87. Is provided.

  Therefore, in this advanced desulfurization gas cooling treatment device 17, the exhaust gas desulfurized by the desulfurization treatment device 12 is introduced into the lower part of the advanced desulfurization gas cooling tower 71 from the gas introduction line 73, while being in the absorption liquid storage portion 72. The basic absorbent is supplied from above the advanced desulfurization unit 75 by the absorbent pump 80 through the absorbent circulation line 79. Then, in this advanced desulfurization part 75, exhaust gas and basic absorption liquid contact, sulfur oxide in exhaust gas is removed highly, and the sulfur oxide concentration in exhaust gas shall be 5 ppm or less. Can do. The basic absorption liquid mist accompanying the exhaust gas is removed and recovered by the advanced desulfurization section demister 76 and stored in the absorption liquid storage section 72. Since the concentration of the basic compound in the basic absorption liquid gradually decreases by repeating the advanced desulfurization treatment, a supply liquid containing a high concentration of the basic compound corresponding to the amount of sulfur oxide removed is supplied to the supply liquid addition line 81. To the absorbent circulation line 79.

  Further, the highly desulfurized exhaust gas is cooled by coming into contact with a cooling liquid (basic absorption liquid) circulating through the gas cooling unit 77, and the gas temperature can be reduced to 50 ° C. or lower. The coolant mist accompanying the exhaust gas is removed and collected by the gas cooling section demister 78. The amount of the recovered coolant increases the amount of moisture condensed from the exhaust gas as compared with the amount of the coolant to be contacted. Therefore, an amount corresponding to the increasing amount of the cooling liquid is supplied to the absorption liquid circulation line 79 via the cooling liquid extraction line 85.

  In the third embodiment, the moisture (cooling process waste liquid) generated during the exhaust gas cooling process in the advanced desulfurization gas cooling processing apparatus 17 is insufficient during the exhaust gas desulfurization process in the desulfurization processing apparatus 12. Supply water supply means for supplying water as supply water is provided.

  That is, as shown in FIG. 5 and FIG. 6, the absorption liquid circulation line 79 in the advanced desulfurization gas cooling treatment apparatus 17 is branched from the downstream side of the absorption liquid pump 80 and an absorption liquid extraction line 82 is provided. The flow rate adjusting valve 91 is provided in the absorption liquid extraction line 82 and is connected to the desulfurization processing apparatus 12. The absorption liquid pump 80 and the flow rate adjusting valve 91 can be driven and controlled by a control device 92. Further, the advanced desulfurization gas cooling processing device 17 is provided with a liquid level sensor 93 that measures the amount of basic absorbent stored in the absorbent storage section 72, and measures the exhaust gas temperature after advanced desulfurization cooling. A gas temperature sensor 94 is provided, and the measurement result is output to the control device 92. Further, the desulfurization treatment device 12 is provided with a moisture deficiency sensor 66 for measuring the deficiency of moisture in the basic absorption liquid evaporated by the heat of the exhaust gas, and outputs the measurement result to the control device 92. Yes.

  Accordingly, the control device 92 receives the measurement result of the liquid level sensor 93 and always knows the liquid level height of the absorption liquid in the absorption liquid storage part 72, that is, the amount of absorption liquid stored in the absorption liquid storage part 72. Then, the drive torque of the absorption liquid pump 80 and the opening degree of the flow rate adjusting valve 91 are controlled so that the storage amount of the absorption liquid becomes a constant amount, and desulfurization is performed from the advanced desulfurization gas cooling processing device 17 through the absorption liquid extraction line 82. It is possible to adjust the supply amount of makeup water (cooling treatment waste liquid) supplied to the processing device 12. Further, the control device 92 receives the measurement result of the water shortage sensor 66 and circulates the coolant so that the amount of makeup water supplied from the advanced desulfurization gas cooling treatment device 13 to the desulfurization treatment device 12 becomes a predetermined amount corresponding to the shortage amount. The cooling efficiency of the heat exchanger 84 provided in the line 83 (see FIG. 6) can be controlled.

  That is, in the advanced desulfurization gas cooling treatment device 17, when the basic absorption liquid is brought into contact with the exhaust gas and cooled by advanced desulfurization, moisture in the exhaust gas is condensed and mixed into the basic absorption liquid. The storage amount of the basic absorption liquid stored in the storage part 72 increases and the liquid level rises. On the other hand, in the desulfurization treatment device 12, when desulfurization is performed by bringing the desulfurization absorption liquid into contact with the exhaust gas, the moisture in the basic absorption liquid evaporates due to the heat of the exhaust gas and becomes insufficient. Then, the control device 92 receives the measurement results of the liquid level sensor 93 and the water shortage sensor 66, and increases the amount of basic absorbing liquid generated in the advanced desulfurization gas cooling treatment device 17 and the water shortage in the desulfurization treatment device 12. The cooling efficiency of the heat exchanger 84 in the advanced desulfurization gas cooling processing device 17 is controlled so that the deficiency amount becomes substantially the same.

  Specifically, when the increase amount of the moisture condensation amount generated in the advanced desulfurization gas cooling processing device 17 is small with respect to the shortage amount of moisture insufficient in the desulfurization processing device 12, the supply amount of the cooling medium in the heat exchanger 84 To increase the amount of moisture to be condensed. On the other hand, when the increased amount of moisture condensed in the advanced desulfurization gas cooling processing device 17 is larger than the insufficient amount of water shortage in the desulfurization processing device 12, the cooling medium supply amount in the heat exchanger 84 is lowered to reduce the cooling efficiency. By reducing, the increase in the amount of moisture to condense is reduced. In this case, the control device 92 controls the cooling efficiency of the heat exchanger 84 so that the exhaust gas temperature after cooling measured by the gas temperature sensor 94 does not exceed a predetermined temperature (for example, 50 ° C.), and the absorbing liquid By controlling the driving torque of the pump 80 and the opening degree of the flow rate adjusting valve 91, only the necessary make-up water amount is replenished to the desulfurization treatment device 12 from the advanced desulfurization gas cooling treatment device 17 through the absorption liquid extraction line 82. .

Here, the exhaust gas processing method and the operating conditions and results of the processing apparatus of Example 3 will be described.
Operating conditions:
Exhaust gas flow rate at the inlet of the desulfurization processing unit 12 ... 200 m ³ N / h
Exhaust gas temperature at the inlet of the desulfurization treatment unit 12 ... 98 ° C
Moisture content of exhaust gas at the inlet of the desulfurization treatment unit 12 8.3 vol%
Exhaust gas temperature at the outlet of the desulfurization processing unit 12 ... 49 ° C
Exhaust gas temperature at the outlet of the gas cooling processor 13 ... 40.2 ° C
Driving results:
Moisture condensation amount in the gas cooling processing unit 13 ... 7.9 kg / h
Moisture deficiency in desulfurization processing unit 12 ............ 7.9kg / h
Therefore, the amount of water condensation in the advanced desulfurization gas cooling treatment device 17 is 7.9 kg / h and the amount of water shortage in the desulfurization treatment device 12 is 7.9 kg / h. There is no need for replenishing water to replenish the processing device 12 from another line. Further, the makeup water supplied from the advanced desulfurization gas cooling treatment device 17 to the desulfurization treatment device 12 is a basic absorbent after the advanced desulfurization treatment, contains sodium salt, and is used as the desulfurization absorbent in the desulfurization treatment device 12. The sodium sulfate concentration in the calcium carbonate suspension becomes 0.1 mol / L, the calcium carbonate dissolution rate ratio becomes 1.4, and the desulfurization performance is improved.

  As described above, in the exhaust gas processing method and processing apparatus according to the third embodiment, the desulfurization processing apparatus 12 is replenished with the cooling processing wastewater generated by the condensation of moisture in the exhaust gas in the advanced desulfurization gas cooling processing apparatus 17. A cooling liquid extraction line 82 that supplies water is provided, and a liquid level sensor 93 that measures the amount of cooling liquid stored in the absorption liquid storage section 72 of the advanced desulfurization gas cooling processing device 17, and the exhaust gas by the desulfurization processing device 12. A water deficiency sensor 66 for measuring the deficiency of water in the basic absorption liquid evaporated by heat is provided, and the controller 92 detects the liquid level height of the absorption liquid measured by the liquid level sensor 93 and the water deficiency sensor. The cooling water efficiency of the heat exchanger 84 is controlled so that the amount of the replenishing water measured by 66 is grasped, and the amount of the reserving water stored is a constant amount and the amount of the replenishing water is a predetermined amount.

  Therefore, the basic absorption liquid evaporated by the heat of the exhaust gas is supplied to the desulfurization processing apparatus 12 by supplying the basic absorption liquid, which is increased by condensation of moisture in the exhaust gas, in the advanced desulfurization gas cooling processing apparatus 17. The shortage of moisture in the inside is replenished, and an increase in processing cost can be suppressed by effectively using the cooling processing waste liquid. In this case, the storage amount of the absorbing liquid becomes a constant amount, and the shortage amount in the desulfurization treatment and the amount of makeup water become the same amount, so that the makeup water from the outside can be made unnecessary and surplus Therefore, it is not necessary to discard the processing waste liquid, which can prevent an increase in operating cost and processing cost.

  Further, the makeup water supplied from the advanced desulfurization gas cooling treatment device 17 to the desulfurization treatment device 12 is a basic absorbent after the advanced desulfurization treatment and contains a sodium salt, and the desulfurization absorbent in the desulfurization treatment device 12. As a result, the concentration of sodium sulfate in the calcium carbonate suspension increases, and the desulfurization performance in the dewatering device 12 can be improved.

  In the third embodiment, the level of the absorbing liquid in the absorbing liquid storage unit 72 of the advanced desulfurizing gas cooling processing device 17 and the insufficient amount of makeup water in the desulfurizing processing device 12 are grasped, and the amount of absorbing liquid stored is ascertained. The cooling efficiency of the heat exchanger 84 is controlled so that the amount of water becomes a constant amount and the amount of makeup water becomes a predetermined amount, but the absorption liquid of the advanced desulfurization gas cooling processing device 17 is the same as in the first embodiment. The liquid level height of the absorbing liquid in the reservoir 72 may be a constant amount, and only the opening degree of the absorbing liquid pump 80 and the flow rate adjusting valve 92 may be controlled.

  The exhaust gas processing method and the processing apparatus according to the present invention supply cooling treatment effluent generated as a result of condensation of moisture in the exhaust gas by cooling as supply water to the desulfurization process. The present invention can be applied to an exhaust gas treatment method and apparatus.

1 is a schematic configuration diagram illustrating an exhaust gas treatment apparatus according to Embodiment 1 of the present invention. 1 is a schematic diagram illustrating a gas cooling processing apparatus in an exhaust gas processing apparatus according to Embodiment 1. FIG. 1 is a schematic diagram illustrating a decarbonation processing apparatus in an exhaust gas processing apparatus according to Embodiment 1. FIG. It is a schematic block diagram showing the exhaust gas processing apparatus which concerns on Example 2 of this invention. It is a schematic block diagram showing the exhaust gas processing apparatus which concerns on Example 3 of this invention. FIG. 6 is a schematic diagram showing an advanced desulfurization gas cooling treatment device in an exhaust gas treatment device of Example 3.

Explanation of symbols

11 Boiler 12 Desulfurization treatment equipment (desulfurization means)
13 Gas cooling treatment device (cooling means)
14 Decarboxylation device (Decarbonation means)
15 Chimney 17 Advanced desulfurization gas cooling treatment device (Advanced desulfurization gas cooling means)
28 Coolant pump (supply water supply means)
61 Coolant extraction line (supply water supply means)
62,91 Flow control valve (supply water supply means)
63, 92 Control device 64, 93 Liquid level sensor (cooling liquid amount measuring means)
65, 94 Gas temperature sensor 66 Moisture deficiency sensor 80 Absorption liquid pump (make-up water supply means)
82 Absorption liquid extraction line (Supplying water supply means)

Claims (10)

  A desulfurization step of removing the sulfur oxide in the exhaust gas by bringing the exhaust gas containing sulfur oxide and carbon dioxide into contact with an absorbing solution containing a basic calcium compound; and the exhaust gas treated in the desulfurization step. Contact with the basic absorption liquid to further remove sulfur oxides in the exhaust gas, and after cooling the exhaust gas in contact with the cooling liquid above it, the cooling liquid mist accompanying the exhaust gas is removed and recovered. An advanced desulfurization gas cooling step, and a decarbonation step of removing carbon dioxide in the exhaust gas treated in the advanced desulfurization gas cooling step, wherein moisture in the exhaust gas is removed in the advanced desulfurization gas cooling step. A method for treating exhaust gas, characterized in that a cooling treatment effluent generated by condensation is supplied as makeup water to the desulfurization step.   2. The exhaust gas treatment method according to claim 1, wherein, in the advanced desulfurization gas cooling step, the exhaust gas treated in the desulfurization step is brought into contact with a basic absorbent, and a concentration of sulfur oxide in the exhaust gas is increased. An exhaust gas treatment method, wherein the sulfur oxide is removed so as to be 5 ppm or less, and the exhaust gas is cooled so as to have a temperature of 50 ° C. or less. In the processing method of an exhaust gas according to claim 1, wherein as the storage amount of the cooling liquid storing highly desulfurized gas cooling step is a predetermined amount, adjusting the supply amount of the makeup water supplied to the desulfurization step A method for treating exhaust gas. 2. The exhaust gas processing method according to claim 1, wherein a storage amount of the coolant stored in the advanced desulfurization gas cooling step is a constant amount, and a supply amount of the makeup water supplied to the desulfurization step is a predetermined amount. so as, the processing method of the exhaust gas and adjusting the gas cooling efficiency in the highly desulfurized gas cooling step. 2. The exhaust gas processing method according to claim 1, wherein in the advanced desulfurization gas cooling step, condensed water obtained by condensing moisture in the exhaust gas is mixed with a coolant stored below and generated. A method for treating exhaust gas, comprising supplying cooling treatment effluent as makeup water to the desulfurization step.   Desulfurization means for removing the sulfur oxide in the exhaust gas by bringing the exhaust gas containing sulfur oxide and carbon dioxide into contact with an absorbent containing a basic calcium compound, and the exhaust gas treated by the desulfurization means An advanced desulfurization section for further removing sulfur oxides in the exhaust gas by contacting with the basic absorption liquid, and a cooling section for cooling the exhaust gas by contacting with the cooling liquid above the exhaust gas and accompanying the exhaust gas thereabove An advanced desulfurization gas cooling means having a demister for removing and recovering the coolant mist, a decarbonation means for removing carbon dioxide in the exhaust gas treated by the advanced desulfurization gas cooling means, and an advanced desulfurization gas cooling means. An exhaust gas processing apparatus, comprising: a replenishing water supply means for supplying cooling treatment waste liquid generated by condensation of moisture in the exhaust gas as make-up water to the desulfurization means.   7. The exhaust gas treatment apparatus according to claim 6, wherein the advanced desulfurization gas cooling means brings the exhaust gas treated by the desulfurization means into contact with a basic absorbent so that a sulfur oxide concentration in the exhaust gas is reduced. An exhaust gas treatment apparatus, wherein the sulfur oxide is removed so as to be 5 ppm or less, and the exhaust gas is cooled so that the temperature of the exhaust gas is 50 ° C. or less. The exhaust gas processing apparatus according to claim 6, wherein the coolant amount measuring means for measuring the amount of coolant stored in the advanced desulfurization gas cooling means, and the measurement result of the coolant amount measuring means, based on the measurement result of the coolant amount measuring means. The exhaust gas processing comprising: a control means for controlling the makeup water supply means so as to adjust a supply amount of the makeup water to the desulfurization means so that a storage amount of the coolant becomes a constant amount. apparatus. The exhaust gas processing apparatus according to claim 6, wherein the coolant amount measuring means for measuring the amount of coolant stored in the advanced desulfurization gas cooling means, and the measurement result of the coolant amount measuring means, based on the measurement result of the coolant amount measuring means. supply amount of the makeup water supplied to the desulfurization unit with the storage amount of the cooling liquid becomes constant amount by controlling the high desulfurizing gas cooling means so that the predetermined amount is provided a control means for adjusting the gas cooling efficiency An exhaust gas processing apparatus characterized by that. 7. The exhaust gas processing apparatus according to claim 6, wherein the advanced desulfurization gas cooling means has a cooling liquid storage section for storing a cooling liquid below, and is obtained by condensing water in the exhaust gas. The exhaust gas processing apparatus is characterized in that a cooling processing waste liquid generated by mixing the above with the cooling liquid in the cooling liquid storage section is supplied to the desulfurization means as makeup water.

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