JP2011050808A - Filler, desulfurizer and system of recovering carbon dioxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system of recovering carbon dioxide from a combustion exhaust gas, having a desulfurizer preventing degradation in carbon dioxide absorption liquid. <P>SOLUTION: By forming a packed bed comprising a plurality of fillers 1 having a water retention gel film 3 in which an epoxy resin 4 containing activated carbon is arranged between gels having a carboxyl group or a hydroxyl group and which is formed on the outer peripheral surface of a cylindrical member 2, and supplying water or seawater to the packed bed as absorption liquid, a sulfurous acid gas is removed from the combustion exhaust gas and then the combustion exhaust gas is introduced to a carbon dioxide absorption tower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a filler, a desulfurizer, and a carbon dioxide recovery system.

  The exhaust gas emitted from the thermal power plant includes carbon dioxide gas and sulfurous acid gas. As an apparatus for recovering carbon dioxide in exhaust gas, an absorption tower that absorbs carbon dioxide in exhaust gas using an organic amine-based alkaline absorption liquid, and a regeneration tower that regenerates the absorption liquid by releasing carbon dioxide from the absorption liquid Has been proposed (see, for example, Patent Document 1).

  However, there has been a problem that sulfurous acid gas in the exhaust gas reacts with the absorbing solution that is alkaline, thereby reducing the carbon dioxide absorption performance of the absorbing solution. Further, there has been a problem that sulfurous acid gas corrodes the material of the recovery device. Therefore, a desulfurizer for removing sulfurous acid gas from the exhaust gas is provided at the front stage of the recovery device or at the bottom of the absorption tower.

  A desulfurizer using a wet flue gas desulfurization tower method in which exhaust gas is spray washed with an alkaline solution such as slaked lime or caustic soda is known. When calcium hydroxide is used for the spray liquid, the spray liquid reacts with sulfurous acid gas to become calcium sulfate, and calcium sulfate can be transferred to the absorbing liquid by entrainment of droplets from the desulfurizer by exhaust gas. The calcium sulfate transferred to the absorbing solution may adhere to the regeneration tower heat transfer surface or heat exchanger. Therefore, the wet flue gas desulfurization tower method using calcium hydroxide is not preferable.

  Sulfurous acid gas tends to be sulfite hydrate in an aqueous solution, changes to hydrogen sulfite ions, and becomes sulfate ions by oxygen. Therefore, exhaust gas cleaning using water or seawater is also performed.

  In such gas cleaning, pressure loss of gas tends to occur when exhaust gas is discharged, and scrubber water flooding occurs. When flooding occurs, there is a problem that the water droplets capturing the sulfurous acid gas migrate to the carbon dioxide recovery device and cause deterioration of the absorbing solution.

JP 2004-323339 A

  The present invention relates to a desulfurizer that removes sulfurous acid gas from combustion exhaust gas and prevents deterioration of an absorbent circulating in a carbon dioxide recovery system, a filler filled in the desulfurizer, and carbon dioxide recovery provided with the desulfurizer. The purpose is to provide a system.

  A filler according to an aspect of the present invention is a filler filled in a desulfurizer, and includes a cylindrical member and a film-like gel that is formed on the outer peripheral surface of the cylindrical member and can retain water. It is.

  A desulfurizer according to one aspect of the present invention is provided with a plurality of the fillers and supplied with an exhaust gas containing sulfurous acid gas, and is provided in an upper portion of the filling tank, and supplies water or seawater to the filling tank. And a water supply unit.

  The carbon dioxide recovery system according to an aspect of the present invention includes the desulfurizer, an absorption tower that absorbs carbon dioxide contained in the exhaust gas that has passed through the filling tank, and discharges the absorbent containing carbon dioxide, The absorption liquid discharged from the absorption tower is supplied, the carbon dioxide gas containing vapor is removed from the absorption liquid, and the absorption liquid is regenerated and discharged, and between the absorption tower and the regeneration tower A regenerative heat exchanger that heats the absorption liquid discharged from the absorption tower and supplied to the regeneration tower, using the absorption liquid discharged from the regeneration tower and supplied to the absorption tower as a heat source. It is to be prepared.

  ADVANTAGE OF THE INVENTION According to this invention, deterioration of the absorption liquid which removes sulfurous acid gas from combustion exhaust gas and circulates in the carbon dioxide recovery system can be prevented.

It is a schematic block diagram of the filler which concerns on embodiment of this invention. It is a figure explaining the water retention state by a water retention gel film. It is a schematic block diagram of the desulfurizer concerning the embodiment. It is a graph which shows the pressure loss of the desulfurizer of a water scrubber system, and the desulfurizer concerning this embodiment. It is a schematic block diagram of the carbon dioxide collection system concerning the embodiment. It is a schematic block diagram of the absorption tower by a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A shows a schematic configuration of the filler 1 filled in the desulfurizer according to the embodiment of the present invention. The filler 1 includes a cylindrical member 2 and a water-retaining gel film 3 formed on the outer peripheral surface and the inner peripheral surface of the cylindrical member 2. The cylindrical member 2 is made of hard plastic or metal having corrosion resistance and heat resistance of about 100 ° C., and has, for example, a Raschig ring shape.

  The water retention gel film 3 is a film formed from a water retention gel. The water-retaining gel is composed of, for example, polyacrylic acid or polyvinyl alcohol, and has a carboxyl group or a hydroxyl group as a functional group.

  As shown in FIG. 2, when the water-retaining gel film 3 has a carboxyl group as a functional group, water molecules 23 are held between the polymer molecular chains 22 crosslinked by the crosslinking agent 21 by hydrogen bonding with water. . The water retention gel film 3 retains about 300 times the volume of the water retention gel film 3. Even when sulfuric acid is mixed in water, the water retention gel film 3 retains about 70 times as much water as the water retention gel film 3.

  As shown in FIG. 1B, the filler may be configured to further include an epoxy resin 4 in which powdered activated carbon is blended between the cylindrical member 2 and the water retention gel film 3. By adding powdered activated carbon, the sulfurous acid gas capture performance is improved. Moreover, since the epoxy resin 4 has strong adhesive strength between the cylindrical member 2 and the water-retaining gel film 3, the water-retaining gel film 3 is peeled off rather than directly forming the water-retaining gel film 3 on the cylindrical member 1. It becomes difficult.

A method for producing such a filler will be described. First, sodium persulfate (Na ₂ SO ₃ ) or sodium sulfite (H ₂ S ₂ O ₅ ) is added to acrylic acid as a polymerization initiator, and the mixture is heated and stirred at 40 to 57 ° C. for about 3 hours. Thereafter, drying and washing are performed, and glutaramide or EDGE (Ethylene Glycol Diglycidyl ether) is added as a cross-linking agent to prepare a water-retaining gel.

  An epoxy resin blended with powdered activated carbon is applied to the cylindrical member. And a water retention gel is coat | covered on an epoxy resin, and a water retention gel is formed into a film by making it dry at 110-125 degreeC. Thereby, a filler as shown in FIG.1 (b) can be manufactured. In the case where the cylindrical member is long at the production start stage of the filler, the epoxy resin may be applied after cutting into a Raschig ring shape, or may be cut after forming the water-retaining gel.

  In addition, what is necessary is just to skip the application | coating process of an epoxy resin, when manufacturing a filler as shown to Fig.1 (a).

  In FIG. 3, an example of a structure of the desulfurizer with which such a filler 1 is filled is shown. 3A is an external perspective view, and FIG. 3B is a cross-sectional view.

  The desulfurizer 30 includes a cylindrical filling tank 31 filled with the filler 1, an exhaust gas dome 32 provided on the outer periphery of the filling tank 31, a water supply dome 33 provided on the filling tank 31, and a bottom of the filling tank 31. The recovery dome 34 provided in the is provided.

  Water (or seawater) is supplied to the water supply dome 33 through the pipe 35. The water in the water supply dome 33 is poured into the filling tank 31 through the dispersion plate 36. In addition, illustration of the dispersion plate 36 is abbreviate | omitted in Fig.1 (a). The water poured into the filling tank 31 is held by the water-retaining gel film 3 of the filler 1.

  A pipe 37 for supplying exhaust gas is provided at the center of the filling tank 31. The exhaust gas supplied from the pipe 37 passes through the filling tank 31 filled with the plurality of fillers 1 and reaches the exhaust gas dome 32. Sulfurous acid gas contained in the exhaust gas is absorbed as sulfite ions in the water retained in the water-retaining gel film 3 of the filler 1. Therefore, the exhaust gas in the exhaust gas dome 32 is obtained by removing the sulfurous acid gas. The exhaust gas collected in the exhaust gas dome 32 is sent out from the pipe 38. The arrows in FIG. 3 indicate the flow of exhaust gas.

  In the desulfurizer 30, the exhaust gas moves from the center portion of the cylindrical filling tank 31 toward the outer peripheral portion. In the filling tank 31, the concentration of sulfurous acid gas in the exhaust gas decreases as it goes to the outer periphery, but the contact area between the exhaust gas and the filler 1 increases, so that the sulfurous acid gas in the exhaust gas can be captured efficiently.

  Excess water and water (sulfite water) of the water-retaining gel film 3 that has absorbed sulfite gas from the exhaust gas are temporarily stored in the collection dome 34 and then discharged from the pipe 39 and collected.

FIG. 4 shows an example of the relationship between the gas flow rate and the gas-side pressure loss of such a desulfurizer 30 and a general water scrubber type desulfurizer. Since the desulfurizer 30 gives the filler 1 a water retention function, flooding does not occur, and the pressure loss is smaller than that of the water scrubber type desulfurizer. Therefore, the exhaust gas flow rate which can be processed from a water scrubber type desulfurizer is large. Moreover, the desulfurizer 30 can be reduced in size.

  FIG. 5 shows a schematic configuration of a carbon dioxide recovery system including such a desulfurizer 30. Water or seawater is stored in the water storage tank 41 and supplied to the packed bed 31 of the desulfurizer 30 through the pipe 35. The supplied water or seawater is held in the water retention gel film 3 of the filler 1.

  Exhaust gas is supplied to the desulfurizer 30 from a thermal power plant boiler via a pipe 37. As described above, the sulfurous acid gas is removed from the exhaust gas supplied to the desulfurizer 30 by the filler 1. Excess water in the desulfurizer 30 and water (sulfurous acid water) in the water retention gel film 3 that has absorbed the sulfurous acid gas from the exhaust gas are discharged from the pipe 39 and collected in the collection tank 42.

  The exhaust gas 102 a from which the sulfurous acid gas has been removed by the desulfurizer 30 is supplied to the lower part of the absorption tower 103 via the pipe 38. In the absorption tower 103, carbon dioxide in the exhaust gas 102a is absorbed by the absorption liquid. The exhaust gas 102b from which carbon dioxide has been removed is discharged from the top of the absorption tower 103. As the absorbing solution capable of absorbing carbon dioxide, for example, an amine compound aqueous solution in which an amine compound is dissolved in water is used.

  The absorption liquid (rich liquid) 104 a that has absorbed carbon dioxide in the absorption tower 103 is supplied to the regeneration tower 105. The regeneration tower 105 heats the rich liquid 104a, releases carbon dioxide gas containing steam from the absorbing liquid, discharges the exhaust gas 102c containing carbon dioxide gas and steam, and regenerates the absorbing liquid.

  The reboiler 106 heats a part of the lean liquid 104 b stored in the regeneration tower 105 to raise its temperature to generate steam, and supplies the steam to the regeneration tower 105. When heating the lean solution 104b in the reboiler 106, a small amount of carbon dioxide gas is released from the lean solution 104b and supplied to the regeneration tower 105 together with the vapor. Then, the rich liquid 104a is heated in the regeneration tower 105 by this steam, and carbon dioxide gas is released.

  Regenerative heat exchange is performed between the absorption tower 103 and the regeneration tower 105 by using the lean liquid 104b supplied from the regeneration tower 105 to the absorption tower 103 as a heat source and heating the rich liquid 104a supplied from the absorption tower 103 to the regeneration tower 105. A container 107 is provided and configured to recover the heat of the lean liquid 104b. The lean liquid 104 b from the regenerative heat exchanger 107 is cooled by the cooler 114 and supplied to the upper part of the absorption tower 103.

  The lean liquid 104 b supplied to the upper part of the absorption tower 103 descends from the upper part in the absorption tower 103. On the other hand, the flue gas 102 a supplied to the absorption tower 103 rises from the lower part toward the top in the absorption tower 103. Therefore, the combustion exhaust gas 102a containing carbon dioxide and the lean liquid 104e come into countercurrent contact (direct contact), and carbon dioxide is removed from the combustion exhaust gas 102a and absorbed by the lean liquid 104e, thereby generating the rich liquid 104a. The combustion exhaust gas 102 b from which carbon dioxide has been removed is discharged from the top of the absorption tower 103.

  The condenser 117 condenses (cools) the exhaust gas 102c containing the carbon dioxide gas and steam discharged from the regeneration tower 105, and separates the carbon dioxide gas and the generated condensate. The carbon dioxide gas 102d discharged from the condenser 117 is stored in a storage facility (not shown).

  The gas cooler 116 cools the exhaust gas 102c discharged from the regeneration tower 105 using cooling water (cooling medium). The condensate from the condenser 117 is supplied to the upper part of the regeneration tower 105.

  Sulfurous acid gas has been removed from the exhaust gas 102 a supplied to the absorption tower 103 by the desulfurizer 30. Therefore, it is possible to prevent the absorption liquid circulating in the carbon dioxide recovery system from reacting with sulfurous acid gas, and to suppress deterioration of the absorption liquid.

Thus, by providing a desulfurizer filled with a filler having a water retention function, it is possible to remove the sulfurous acid gas from the combustion exhaust gas and prevent deterioration of the absorption liquid circulating in the carbon dioxide recovery system.
In the above embodiment, as shown in FIG. 5, the desulfurizer 30 is provided in the front stage of the absorption tower 103. However, as shown in FIG. 6, the desulfurizer including the filler 1 is provided in the absorption tower 103 ′. It may be. Water or seawater is supplied from the pipe 51 and held on the water-retaining gel film 3 of the filler 1. As the exhaust gas supplied from the pipe 52 passes through the filler 1, sulfurous acid gas in the exhaust gas is removed. The exhaust gas from which the sulfurous acid gas has been removed comes into contact with the absorption liquid (lean liquid) in the absorption tower 103 ′, and carbon dioxide is absorbed. The absorption liquid (rich liquid) that has absorbed carbon dioxide is sent to the regeneration tower 105 of FIG. The water (sulfite water) of the water-retaining gel film 3 that has absorbed the sulfurous acid gas from the exhaust gas is collected from the pipe 53.

  In the above embodiment, the powdered activated carbon may contain iron hydroxide. Thereby, the oxidation of sulfurous acid gas is promoted, and sulfate ions are absorbed by the water retained in the filler.

  In the above embodiment, the filler 1 may be a pole ring coated with a water-retaining gel film.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Filling material 2 Cylindrical member 3 Water retention gel film 4 Epoxy resin

Claims (5)

A filler filled in the desulfurizer,
A cylindrical member;
A film-like gel that is formed on the outer peripheral surface of the cylindrical member and can retain water;
A filler comprising:   The filler according to claim 1, further comprising an epoxy resin containing activated carbon between an outer peripheral surface of the cylindrical member and the gel.   The filler according to claim 1 or 2, wherein the gel has a carboxyl group or a hydroxyl group. A filling tank filled with a plurality of the fillers according to any one of claims 1 to 3 and supplied with exhaust gas containing sulfurous acid gas;
A water supply unit provided at an upper portion of the filling tank, and supplying water or seawater to the filling tank;
A desulfurizer comprising. A desulfurizer according to claim 4;
An absorption tower for absorbing carbon dioxide contained in the exhaust gas that has passed through the filling tank into an absorption liquid, and discharging the absorption liquid containing carbon dioxide;
An absorption liquid discharged from the absorption tower is supplied, a carbon dioxide gas containing steam is removed from the absorption liquid, and a regeneration tower that regenerates and discharges the absorption liquid;
Absorbing liquid provided between the absorption tower and the regeneration tower, discharged from the regeneration tower and supplied to the absorption tower as a heat source, and discharged from the absorption tower and supplied to the regeneration tower A regenerative heat exchanger that heats,
A carbon dioxide recovery system.

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