TWI280152B - Exhaust gas treatment system and exhaust gas treatment method - Google Patents

Exhaust gas treatment system and exhaust gas treatment method Download PDF

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Publication number
TWI280152B
TWI280152B TW94137539A TW94137539A TWI280152B TW I280152 B TWI280152 B TW I280152B TW 94137539 A TW94137539 A TW 94137539A TW 94137539 A TW94137539 A TW 94137539A TW I280152 B TWI280152 B TW I280152B
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Taiwan
Prior art keywords
exhaust gas
desulfurization
air heater
gas treatment
dust collecting
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TW94137539A
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Chinese (zh)
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TW200637643A (en
Inventor
Hiromitsu Nagayasu
Yasutoshi Ueda
Morio Kagami
Toshihide Noguchi
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Mitsubishi Heavy Ind Ltd
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Publication of TW200637643A publication Critical patent/TW200637643A/en
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Publication of TWI280152B publication Critical patent/TWI280152B/en

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Abstract

An exhaust gas treatment system is provided that can sufficiently remove pollutants such as SO3 contained in combustion exhaust gas at low cost. In the exhaust gas treatment system for removing pollutants such as SO3 contained in combustion exhaust gas, there is provided dissolved salt aqueous solution sprays 35A, 35B, and 35C, that spray an Na2SO4 aqueous solution obtained from desulfurization effluent of a wet desulfurization system, into a flue though which the combustion exhaust gas flows.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treatment device and an exhaust gas treatment method for removing pollutants in combustion exhaust gas such as s〇3. [Prior Art] The combustion exhaust gas generated when burning fossil fuel or garbage in a combustion furnace contains sulfur trioxide (s〇3), hydrogen fluoride (HF), hydrogen chloride (HC1), silver chloride (HgCl), hydrogen sulfide. (HJ) Contaminants such as carbon monoxide (c〇s). The release of this type of pollutant into the atmosphere will adversely affect the environment. Therefore, according to law or self-discipline, seek a treatment below a certain concentration. Various exhaust gas treatment devices have been previously proposed to accomplish this. An example of S污染3 as a pollutant is described. S〇3 is mainly produced by oxidation of a part of s〇2 produced by combustion of a fuel containing sulfur (heavy oil or coal, etc.) in a high temperature environment. Therefore, the existence of s〇3 is only a few percent of S〇2. However, s〇3 is called the cause of air blockage, corrosion or flue corrosion, and if it is discharged from the self-cooling, it becomes the cause of the formation of violet smoke. Therefore, the manufacturer expects to discharge; The number Ρρ1Ή is below. It is known that an ammonia gas injection method in which ammonia gas is injected into a combustion exhaust gas is used as a method of removing S03. The ammonia injection method produces ammonium sulfate and dust as a product of combustion exhaust gas. Sulfuric acid can generally be recovered as a solid by a dry electrical dust collector, but heavy metals contained in fuels such as heavy oil are also recovered together with ammonium sulfate because I05794.doc 1280152 needs to be treated separately before being released into the surrounding environment. At this point, the ammonia injection method has disadvantages in terms of sighing costs and operating costs. In addition, an excessive amount of 筠々~ 虱虱 is injected for the production of waste rock and acid, so the desulfurization waste water of the wet desulfurization device installed on the downstream side is taken as #, 八虱瑕^. In this case, in order to comply with environmental standards, the desulfurization wastewater needs to be treated. In addition, due to the need to continuously supply ammonia gas, the large consumption of u-milk will hinder the cost of operation. On the other hand, in order to remove the dust generated by the ammonia injection and the dust in the combustion exhaust gas, there is a case where an electronic dust collecting device or a cleaning device (patent No. 3564366) is provided on the downstream side of the flue. The electronic dust collector or the dielectric gas cleaning device can also remove S〇3 while removing dust. (9) Even with the use of these devices, in the case of processing high concentrations of S〇3, economical treatment is used. The electronic dust collector or the dielectric gas cleaning device of the capacity is difficult to capture sufficient S03. [Invention] The present invention has been developed in the above-mentioned circumstances, and the object of the present invention is to provide a combustion exhaust gas. In order to solve the above problems, the exhaust gas treatment device and the exhaust gas treatment method according to the present invention employ the following method. That is, the exhaust gas treatment of the present invention is adopted. The apparatus is an exhaust gas treatment device for removing pollutants such as sulfur trioxide, hydrogen fluoride, hydrogen chloride, silver chloride, hydrogen sulfide, sulfurized carbon monoxide or the like contained in the exhaust gas, and has a spray mechanism that is sprayed in the flue through which the combustion exhaust gas flows a dissolved salt of a chloride, hydroxide, sulfate or carbonate containing any of Nas, κ, Mg, Ca, 105794.doc 1280152 An aqueous solution. In the flue through which the combustion exhaust gas flows, the spray contains Na, K, Mg,
An aqueous solution of a dissolved salt of a vapor, hydroxide, sulfate or carbonate of any of Ca. As a result of active discussion, the present inventors have found that if an aqueous solution containing a salt of a sulfate or a carbonate of any of Na, K, Mg, or Ca is used, the sulfur dioxide, hydrogen fluoride, hydrogen chloride, silver sulfide, and sulfur sulfide can be effectively removed. Contaminant such as hydrogen or sulphate "L-carbon monoxide". An aqueous solution containing a salt of a sulfate or a carbonate of any of Na, K, Mg, or Ca (for example, a reaction product which can be used as a treatment step) It is easy and inexpensive to obtain. Therefore, the exhaust gas treatment can be carried out simply and inexpensively without using a high-priced chemical liquid. As for the dissolved salt, NaCn, NaOH, Na2S04, Na2C03, KC1, KOH, K2S04, k2c〇3, KHC〇3 can be cited. , MgCl2, MGS〇4,
CaCl2 〇 • As for the sulfur oxide contained in the combustion exhaust gas, S〇2 may be cited in addition to SO3, but the present invention is preferably applied to the treatment of S〇3, and is not designed to remove S〇2. In addition, as for the pollutants, although a representative trioxide furnace is listed, it may be applied to other substances. For example, hydrogenated hydrogen (HF), chlorinated|nitrogen (HC1), silver chloride (HgC1), hydrogen sulfide (H2S), sulfurized-oxidized carbon (cos), and the like. As for the spray mechanism, a two-fluid nozzle is preferably used in order to make the spray droplets fine. Further, it is preferable that the exhaust gas treatment device includes a wet desulfurization device, and the aqueous solution is subjected to the above-described wet desulfurization to carry out desulfurization wastewater. When the wet desulfurization apparatus is subjected to the nano or magnesium hydroxide method, the desulfurization wastewater contains Na or Mg sulfate, i.e., 28〇4 or _〇4. By spraying the desulfurization wastewater, it is possible to avoid consuming new liquid and removing p substances such as S〇3. Thereby, extremely low and inexpensive exhaust gas treatment is possible. In the above-mentioned exhaust gas treatment device, the outlet temperature of the above-mentioned spray mechanism is kept at um, preferably 14 (rc or more. In order to spray the squid, the six masses in the self-propelling mechanism, it is necessary to evaporate the dissolved salt around. The water a LL effect removes the watery tomb of the coincident dyeing ditch, so the second must be in the ejected liquid to send the ancient text and the car father is to keep the ambient temperature in the steam and dip X, in order to improve the reaction Sex, it is better to keep the concentration of pollutants such as SO3 which reacts with dissolved salts, the surname of w, and the phoenix of the road. Therefore, the spray mechanism should be kept for 13 generations or more, preferably 14G. °C or more. Cry = the exhaust gas treatment device of the month is equipped with an air heater 'heating the heat obtained from the U exhaust gas, heating the air supplied to the combustion furnace, and the spray mechanism is disposed on the upstream side of the heater The raw furnace contains sulfur trioxide in the waste milk, and the sulfur trioxide is produced by the force:: 曰 叙 加热器 heater. In the present invention, by setting the spray mechanism to the upstream side, the trioxide is removed on the upstream side of the heater. Sulfur and other pollution to prevent heater rot The gas is obvious: the upstream side of the heating benefit is absorbed by the air heater to burn the waste == the second temperature is higher (for example, 300~35〇°c not yet). Therefore, the water evaporation of the commercial is used to improve the removal of pollutants. The exhaust gas treatment device of the present invention comprises: an air heater which heats the air supplied to the combustion furnace by the heat obtained by burning the exhaust gas, and an electronic dust collecting device which is disposed in the air heater a downstream side, and the spray mechanism is disposed between the air heater and the electronic dust collecting device
For example, if sulfur trioxide is contained in the combustion exhaust gas, the sulfuric acid sulfonate (four) sub-dust collection device produced by sulfur trioxide is used. In the present invention, the spray mechanism is disposed between the air heater and the electronic dust collecting device, and the pollutants are removed on the upstream side of the electronic dust collecting device to prevent corrosion of the electronic dust collecting device. Further, compared with the method of removing ammonia gas from the upstream side of the electronic dust collecting device, the product generated between the material and the pollutant in the combustion exhaust gas becomes simple. In the ammonia injection method, the process of treating heavy metal members contained in the sulfuric acid recorded as a product must be carried out separately. In the present invention, since a dissolved salt (e.g., Na2S〇4 or MgS〇4) containing any of Na, K, and a is used instead of ammonia gas, the step of treating sulfur is not required. X ’ does not use the ammonia injection method, so dust generation can be suppressed. Further, in the exhaust gas treatment device of the present invention, there is provided an air heater that heats air supplied to the combustion furnace by heat obtained by burning the exhaust gas; and an electronic dust collecting device disposed on a downstream side of the air heater And a wet desulfurization device disposed on a downstream side of the electronic dust collecting device, wherein the spraying mechanism is disposed between the electronic dust collecting device and the wet desulfurization device and located in the wet desulfurization device Recently. The product produced between the dissolved salt and the pollutants in the combustion exhaust gas is easily dissolved in the desulfurization wastewater of the wet desulfurization device. Further, since the spray mechanism of the spray 105794.doc -10- 1280152 is placed in the vicinity of the wet desulfurization apparatus, the product flows into the storage portion of the desulfurization waste water of the wet desulfurization apparatus. The product which has flowed into the storage portion of the desulfurization waste water is dissolved in the desulfurization waste water and is treated together with the desulfurization waste water. Therefore, it is not necessary to separately carry out the treatment step of the product, and the equipment can be simplified. For example, in the case of a wet desulfurization apparatus using a caustic soda method, it is possible to use Na2S〇4 as a dissolved salt, and the S〇3 in the combustion exhaust gas is used.
Na2S04+ S03+ 2H20 —2NaHS〇4.H2〇 The reaction formula is converted to NaHS〇4.H2〇, which is easily dissolved in desulfurization wastewater. Thus, there is an advantage that solid treatment such as the 4-gas injection method is not required. The external exhaust gas treatment device of the present invention includes: an air heater that heats and supplies the gas to the combustion chamber by the heat obtained by burning the exhaust gas: the electronic dust collector is disposed downstream of the air heater The second and wet desulfurization device are disposed on the downstream side of the electronic dust collecting device, and the mist mechanism can be disposed at any two of the following three places, that is, the upstream side of the air force <,, And between the air heater and the electronic dust collecting device, and between the electronic dust collecting device and the wet desulfurization device, and closest to the 5-wet wet desulfurization device. By setting the nozzle mist mechanism in two places, the concentration of pollutants can be greatly reduced. * The right side-side spray position is used as the upstream side of the air heater, and the combustion exhaust gas temperature on the upstream side of the work gas heater is maintained at a high temperature by this, so that the temperature of the combustion exhaust gas on the downstream side can be prevented from dropping by two; The recovery of pollutants at the downstream side of the sprayer is high. 105794.doc 1280152 The exhaust gas treatment device of the invention has a wet dielectric gas cleaning device. I can also use the wet electronic dust collector or the dielectric type, the main and the strong pollutants in the combustion exhaust gas, and the spray device for spraying the dissolved salt. <The clothing is compact. In particular, the electric gas cleaning device is excellent in removing so3, and is preferably suitable for the purpose of removing S03.
Further, the exhaust gas treatment method of the present invention is an exhaust gas treatment method for removing pollutants such as sulfur dioxide, hydrogen peroxide, hydrogen chloride, silver chloride, hydrogen sulfide, sulfurized-emulsified carbon, and the like, which are contained in the combustion exhaust gas. :: In the flue, an aqueous solution containing a dissolved salt of a chloride, a porphyrin, a sulfate or a carbonate of any of Na, K, Mg, or Ca is sprayed. 3 Water (4) having a dissolved salt of chloride, hydroxide, sulfate or carbonate of any of Na, K, Mg, Ca, (for example, a reaction product of a certain treatment step) can be relatively easy and inexpensive Obtained. So it can be simple and cheap
Exhaust gas treatment is carried out. As the dissolved salt, NaC NaOH, Na2S04, Na2C03, κα, KOH, K2S〇4, K2C03, KHC03, MgCl2, MgS04, CaCl2 can be cited. As for the oxide of sulfur contained in the combustion exhaust gas, S〇2 may be mentioned in addition to so3, but the present invention is preferably applied to the treatment of S03, and is not designed to remove s〇2. Further, as the pollutant, a representative sulfur trioxide can be cited, but it can also be applied to other substances. For example, hydrogen fluoride (HF), hydrogen chloride (HC1), vaporized silver (HgCl), hydrogen sulfide (HJ) sulfide carbon monoxide (c〇s), and the like. 105794.doc • 12· 1280152 By the present invention, the following effects can be achieved. The use of an aqueous solution containing a salt of a sulfate or a carbonate of any of Na, K, Mg, or Ca can remove pollutants such as s〇s, so that it is possible to carry out exhaust gas treatment without injecting a high-priced liquid. Further, when the aqueous solution is supplied by the desulfurization waste water, the exhaust gas treatment can be easily carried out at a low cost. [Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. [First Embodiment] Hereinafter, the present invention will be described with reference to Fig. 1! The embodiment will be described. In the present embodiment, an exhaust gas treatment device using a wet desulfurization device using a caustic soda method is applied. Fig. 1 shows an exhaust gas treatment device in the present embodiment. The exhaust gas treatment unit 1A is disposed in the flue 5 on the downstream side of the steel furnace (burning furnace) 3, and has: a de-sparing device 7, an air heater 9, a #-type electronic grinder η, a wet desulfurization device 13. Dielectric gas cleaning device 15 and cigarettes 17. The pin furnace 3 is used as a heavy oil burning furnace for burning heavy oil containing a large amount of sulfur. The de-sparing device 7 removes nitrogen oxides (Nox) contained in the combustion exhaust gas from the steel furnace 3. The air heater 9 is configured to exchange heat between the combustion exhaust gas and the combustion air supplied from the fan 1A. Thereby, the combustion air is heated by the sensible heat of the combustion exhaust gas, and is supplied to the boiler 3. The dust in the combustion exhaust gas is captured. The dry electronic dust collector 11 is electrostatically charged. 105794.doc 1280152 The wet desulfurization device 13 has: an absorbent sprayer 2〇 sprayed with a solution containing NaOH as an absorbent; a packed bed 22 disposed under the absorbent sprayer 20; a storage portion 24, It is disposed below the filling layer ^. The filling layer 22 is configured to be provided with, for example, a filler made of a resin. Between the absorbent atomizer 20 and the reservoir portion 24, an absorbent supply pump 26' is provided by the absorbent supply pump 26 to extract the absorption solution in the reservoir portion 24. In the storage crucible 24, the NaOH solution is supplied from the NaOH solution supply mechanism 24a, and the air is supplied from the air supply mechanism 24b. The absorbing solution ejected from the atomizer 20 absorbs S 〇 2 in the combustion exhaust gas from the absorbing liquid in the packed bed 22. The s〇2 absorbed by the absorption solution is converted into NaHS〇3, which is reacted with oxygen to form Ν^〇4. The desulfurized wastewater containing this is discharged to the outside through a drain pipe 28. Although the S〇3 does not chemically react with the absorbing solution in the wet desulfurization apparatus 丨3, a small amount is removed by colliding or aggregating with the particles of the absorbing solution. In the storage of π卩24, not only Na2S〇4 but also NaHs〇3 is dissolved, but it is sufficiently oxidized by the air supply mechanism 24b, preferably converted into Na2S04 〇'丨 electric gas cleaning device 15 will be sprayed Dielectric particles such as water enter the electric knife pole, and the charged dust or S03 is trapped in advance by the life force acting between the respective dielectric particles. Alternatively, a wet electronic dust collecting device may be used instead of the dielectric gas cleaning device 15. In the present invention, the desulfurized wastewater stored in the storage portion 24 of the wet desulfurization unit 13 is used to remove S〇3. In the desulfurization wastewater, the aqueous solution of Na2S04, the NaOH solution. , mainly containing dissolved salt, NaJO4 dissolved in water, and the other part is supplied by the NaOH solution supply mechanism 24a. The desulfurized waste water is pumped to the wet desulfurization apparatus by the suction pump 32 and the extraction pipe.
The upstream side of the set 13 is sprayed into the flue 5 by means of a dissolved salt sprayer (mouth mist mechanism) 35A, B, C. Desulfurization wastewater is preferably used to make liquid by pressurized air
The micronized two-fluid nozzle is carried out (4). The diameter of the desulfurized waste water to be sprayed is preferably about ΙΟμηι. The S03 in the combustion exhaust gas is removed by the following formula by using an aqueous solution of Na2S〇4 contained in the desulfurization waste water:
Na2S04 + S03 + 2H20-> 2NaHS04-H20 In turn, s〇2 in the exhaust gas is also removed by the aqueous solution of NaOH contained in the desulfurization wastewater. The position of the spray desulfurization waste water is selected from any of the following three: • The position between the denitration device 7 and the air heater 9 and the position between the air heater 9 and the dry electronic dust collector η B. Position C between the dry electronic dust collecting device u and the wet desulfurization device 13. Of course, it is also possible to select both the position a and the position B or the position A and the position C at the same time. The temperature at position A is about 300 to 35 (rc, the temperature at position B is about 160 to 200 ° C, and the temperature at position C is about 160 to 2 〇 (rc. The advantages of selecting each position A to C are as follows. When the spray position of the desulfurization waste water is selected on the upstream side of the air heater 9, that is, the position A, the upstream side of the air heater 9 can be removed. § 105794.doc -15· 1280152 Therefore, it is possible to prevent combustion due to exhaust gas. The sulfuric acid generated by the sulfur trioxide erodes the air heater 9. Further, the upstream side of the air heater 9 maintains a relatively high temperature (for example, 3 〇〇 to 35 前) before absorbing the sensible heat of the combustion exhaust gas by the air heater 9. 〇c). Therefore, it is possible to promote the evaporation of the water of the Na2S〇4 aqueous solution particles in the desulfurized wastewater which is ejected, and to remove the efficiency of the S〇3. The position B is located on the upstream side of the dry electronic dust collecting device. Therefore, by spraying the desulfurization waste water, it is possible to prevent the dry type electronic dust collecting device U from being corroded by the sulfuric acid generated by the sulfur trioxide in the combustion exhaust gas. Further, the s〇 is captured in comparison with the ammonia gas injection method previously used. The treatment of the product after 3 becomes simple, that is, the spray desulfurization waste In this case, the product is referred to as a water-soluble sulfate, and the treatment is extremely simple compared to the ammonia injection method in which a step of treating a solid product containing ammonium sulfate or a heavy metal is required. The treatment can be co-operated with the wet desulfurization device 13, which can reduce the equipment cost. Moreover, the ammonia gas injection method generates ammonium sulfate ash which is a complex product, and if the caustic soda method is used to spray the desulfurization wastewater, the product dust is generated. However, it is advantageous in that the treatment is simple. The position C is disposed in the vicinity of the wet desulfurization device, so that the product of 8〇3 flows to the downstream side together with the combustion exhaust gas, and flows into the storage portion 24. Therefore, The product produced from the desulfurization wastewater injected from the position C is collected by the desulfurization device 11, and then treated with the desulfurization wastewater, so that the desulfurization wastewater treatment equipment can be co-operated.
Further, if the position of the spray desulfurization waste water is selected as the position A and the position B, or the position A and the position C, the SO3 concentration can be greatly reduced. For example, only when position A 105794.doc -16-1280152 cannot remove so3 below the allowable concentration, the desulfurization waste water spray mechanism can be added at position β or position C. The spray position of the side of the air heater 9 as the upstream side of the air heater 9, that is, the temperature of the upstream side of the positional heat heater 9, can be maintained at a specific temperature by the ability of the boiler 3 on the upstream side thereof, so that the spray can be prevented as much as possible. The temperature of the combustion exhaust gas produced by the sulfur wastewater is lowered. Therefore, the position of the lower side of the air heater 9 and the temperature of the combustion exhaust gas in the position c are less lowered, so that the temperature can be maintained at the necessary temperature level for removing s〇3. The exhaust gas treatment device 1A of the above configuration is used in the following manner. In the following description, a case where the dissolved salt sprayer 35 is provided at the position A and the position B will be described as an example. After the heavy oil containing a large amount of sulfur components is burned in the boiler 3, the combustion exhaust gas containing s〇2 is discharged to the downstream flue 5 . S〇2 is oxidized in the high temperature portion of the boiler 3 or the denitration device, and is converted into S03. Most of the S?3 can be removed by the desulfurization waste water atomized by the dissolved salt sprayer 35A at position A. Here, the desulfurization wastewater contains NaJO4 as a main component,
The reaction of Na2S04 + S03 + 2H20-^2NaHS〇4-H20 recovered S03. In this way, the reaction product of s〇3 is highly soluble, so that it is discharged to the outside in the state of an aqueous solution. Furthermore, the position of the burnt gas is 300 to 350 ° C. The exhaust gas is removed, and the combustion exhaust gas is passed through the air heater 9, and a part of the sensible heat is transmitted to the combustion air supplied by the fan 10, and reaches the position B. At this time, the temperature of the combustion exhaust gas is lowered to 16 〇 2 (9). 105794.doc 1280152 In position B, the desulfurization waste water atomized by the dissolved salt sprayer 35] B is sprayed again, thereby removing S03. Most of the combustion exhaust gas of the S〇3 is removed at the position A and the position B, and after the dust is removed by the dry type electronic dust collecting device 11, the wet desulfurization device 丨3 is flown. In the wet desulfurization apparatus 13, S?2 is removed by the absorption solution sprayed through the absorbent atomizer 2. In the storage unit 24, NaOH reacts with S〇2 to generate NaJCU. The solubility of NaJO4 is high, and a part of it is discharged to the outside through a drain pipe 28 in the state of an aqueous solution of Na2S〇4. On the other hand, other aqueous solutions of Na2S〇4 are sucked up by the air pump 32 and transported to the respective dissolved salt sprayers 35A and B via the extraction pipe 3. The combustion exhaust gas of S〇2 is removed from the wet desulfurization apparatus 13, and introduced into the dielectric gas cleaning apparatus 15 where the remaining dust and s〇3 are removed, and then discharged from the chimney 17 to the outside. The following effects can be attained by using the method of the present invention. By dissolving the salt NaeCU aqueous solution to remove s〇3, it is only necessary to supply the Na2S〇4 aqueous solution by desulfurization wastewater, without injecting a new chemical solution. Therefore, it is extremely easy to construct and remove s〇3 at a low cost.
The reaction product between NaJO4 and SO3 has a high solubility, so that it can be treated in an aqueous solution state. Therefore, the treatment becomes extremely simple as compared with the ammonia injection method in which solid matter treatment is required. Since it is not necessary to use the ammonia gas injection method for removing S?3, the processing equipment for the product produced by the ammonia gas injection method is not required, thereby reducing the cost. In addition, the operating cost can be reduced because there is no need to continuously supply ammonia gas. In the two stages of position A and position B, the desulfurization waste is sprayed, so that the concentration of S〇3 can be greatly reduced by 05794.doc 1280152. Further, by using in combination with the dielectric gas cleaning device 15 capable of removing a specific amount of S03, the amount of S〇3 treatment using the desulfurization wastewater can be reduced, so that the self-extracting tube 30 to the dissolved salt sprayer 35A, B, C can be reduced. The equipment is compact. Further, in the present embodiment, desulfurization waste water should be used for obtaining Na2S〇4, but an aqueous solution of NkSO4 may be produced by other means to eject and remove S〇3 from positions A to c. Further, in the present embodiment, the wet desulfurization apparatus 13 using the caustic soda method will be described as an example, but the same applies to a wet desulfurization apparatus using a magnesium hydroxide method of Mg(0H)2. In this case, MgS04 contained in the desulfurization wastewater is used as a dissolved salt for removing S03. Further, as for the glutamine salt, NaJO4 or MgS〇4 is exemplified, but as long as it is a salt of a sulfate or a carbonate of any of Na, K, Mg, or Ca, it is possible to remove a pollutant such as S〇3. Further, SO3 is used as an example of the pollutant to be removed, but it is also possible to remove substances such as hydrogen sulfide (HF), hydrogen chloride (HC1), silver chloride (HgCl), and argon sulfide (COS). [Second Embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 2 . In the present embodiment, an exhaust gas treatment apparatus using a wet desulfurization apparatus of a lime gypsum method is applied. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Fig. 2 shows an exhaust gas treatment device in the present embodiment. 105794.doc • 19-1280152 The exhaust gas treatment device 1B removes sulfur oxide by using limestone (CaC〇3) supplied from the limestone supply mechanism 24c as an absorbent. The product produced by the lime gypsum method is a CaS〇4 which is difficult to be used, so it is difficult to be as good as the first! Embodiments Desulfurization wastewater is used to remove S〇3. Therefore, in the present embodiment, the second wet desulfurization apparatus is provided in the middle of the flue 5 in comparison with the wet desulfurization garment 13; the apparatus uses the caustic soda method. The second wet type desulfurization apparatus 38 includes a second storage unit 40 upstream of the wet desulfurization unit (4), and a ν & 〇η supply structure publication & and an air supply unit 4〇b are connected to the second storage unit 4〇 The WNa〇H solution and air are supplied to the second storage unit 4〇. The solution (10) supplied to the second storage unit 4 is dissolved in the absorption liquid, and is ejected from the second absorbent atomizer 44 into the second storage unit 40 in the smoke C by the second absorbent supply pump 42. The desulfurization waste containing the aqueous solution of NaJO4 is sent to the upstream side of the second absorbent atomizer 44 via the extraction pump 48 through the extraction pump 46, and by dissolving the salt sprayer (spray mechanism) 35A, B , c is sprayed into the flue 5 . In the case of Benbe's % grievance, the side of the wet desulfurization device 13 of the lime gypsum method is used. Further, a second wet desulfurization apparatus 38 using a caustic soda method is used to form a dissolved salt of Na2S〇4, and desulfurized waste water mainly containing the NhS〇4 is sprayed into the flue 5 on the upstream side. Thereby, NkS〇4 for removing s〇3 can be supplied without providing a device for mass-producing NkSO4. Further, the size of the second wet type desulfurization apparatus 38 is only required to obtain a NaJCU which is necessary for removing s〇3. The amount of s〇3 present in the combustion exhaust gas is only a few percent of S〇2, so that the size of the second wet desulfurization unit 38 is substantially smaller than that of the wet desulfurization apparatus 13. 105794.doc -20- 1280152 In addition to the second wet desulfurization device 38 of Fig. 2 installed in the middle of the flue 5, a small wet third method using the caustic soda method may be disposed outside the flue 5 Device 50. In this case, the branch pipe 52 is connected to the flue 5, and a part of the combustion exhaust gas is guided to the third wet desulfurization device 50. In the third wet type desulfurization apparatus 50, desulfurization similar to that of the second wet type desulfurization apparatus 38 is performed, and desulfurization waste water containing an aqueous solution of Na2S〇4 is produced in the third storage P54. The desulfurization waste water is sent to the dissolved salt sprayer (spray mechanism) 35A, B, and C through the suction pump 56 through the suction pump 56. In the present embodiment, the second wet type desulfurization device 38 is used. The third wet type desulfurization apparatus 50 uses a caustic soda method, but a magnesium hydroxide method can also be used. Further, as for the dissolved salt, not only NhJSO4 or MgS〇4 but also a salt of a sulfate or a carbonate of any of & K, Mg, and Ca may be used, and a pollutant such as S〇3 may be removed. Further, S〇3 is used as an example of the removed pollutant, but hydrogen fluoride (HF), vaporized hydrogen (HC1), vaporized silver (HgCl), hydrogen sulfide (H2S), sulfurized carbon monoxide (cos), or the like may be removed. Further, the second wet desulfurization device 38 and the third wet desulfurization device 5 may be used, and the NazSCU aqueous solution or the MgS〇4 aqueous solution may be directly supplied to each of the Α to 〇 positions. [Examples] The SO3 removal test will be described with reference to Figs. 4 to 6 . The test apparatus is schematically shown in Fig. 4 . The test apparatus 100 has an LPG furnace 1〇1, a cold arsenic tower 103 disposed downstream of the LPG furnace 〇1, and a wet electronic dust collecting device 105794.doc-21 - 1280152 105 〇LPG disposed downstream of the cooling tower 1〇3 Furnace 0 is a combustion furnace for burning liquefied petroleum gas (Uquefied), which directs the combustion exhaust gas of the liquefied petroleum gas to the cooling tower 103 on the downstream side. The cooling tower 103 has a flow passage at an angle of about 450 mm, downstream thereof. The side has a storage portion 109. The water stored in the storage portion 109 is pumped by the pump and is ejected by two water sprayers 113a, b. The upstream water sprayer 13 & supply φ 1.4 m3 / h The volumetric flow ratio (l/g) of water to the gas flowing through the flow channel is 〇·5. The water atomizer 113b on the downstream side is supplied with water of 2·8 m3/h, and the volume of the gas flowing through the flow channel The flow ratio (L/G) is 1.0. On the upstream side of the cooling tower 103, a dissolved salt sprayer 115 using a two-fluid nozzle is disposed. The self-dissolving salt sprayer 115 ejects a droplet having a diameter of about 2 〇 μηη & Between the LPG furnace 101 and the cooling tower 103, a male 3 supply mechanism 107' is provided to adjust the initial S03. Concentration: The inlet of the cooling tower 103, the upstream side of the water sprayers 113a, b, and the outlet of the cooling tower 103 are provided with a temperature sensor. Also, at the inlet of the cooling tower ι〇3, the outlet of the cooling tower 103 And an outlet of the electronic dust collecting device 1〇5, and an S03 concentration sensor is provided. The test in this embodiment is to set the inlet temperature of the cooling tower 103 to 185 ° C, the inlet SO of the cooling tower 103; The test was carried out under the conditions of 170 ppm. The middle ' indicates the test result using the above test apparatus. In Fig. 5, 'the horizontal axis is the dissolved salt solution supply concentration [wt%], and the vertical axis is the cooling & 丨105794. Doc -22- 1280152 SO3 concentration [ppm] at the outlet. In this example, an aqueous solution and caustic soda method are used to desulfurize wastewater, and the aqueous solution uses Na2S04, MgS04 and NaOH as dissolved salts. As shown in Fig. 5, it will be borrowed. When the initial 8〇3 concentration adjusted by the S〇3 supply mechanism ι7 is 170 ppm, SO3 can be removed to 60 ppm or less regardless of the dissolved salt solution used. Therefore, if s〇3 is provided on the downstream side. Electronic dust collector or dielectric with a removal rate of about 90% The gas purifying device can reduce the SO3 concentration to several ppm and prevent the generation of purple smoke. Fig. 6 shows the test results when the 5 wt% Na2S〇4 aqueous solution is changed to flow rate injection. In the same figure, The horizontal axis aNa2S〇4 aqueous solution spray flow rate [L/hr], the left axis is the s〇3 concentration [ppm] at the outlet of the cooling tower i 03, and the right axis is the spray outlet temperature [°C]. The graph shows that the spray outlet temperature decreases proportionally as the NajO4 aqueous solution spray rate rises. When the NajO4 aqueous solution spray flow rate is 5 〇 [L / hr], that is, at the spray outlet _ temperature is about n 〇 ° C, the s 〇 3 concentration is slightly more than 60 ppm; and the spray outlet temperature is 140 ° C when the SO3 The concentration dropped significantly to 4〇ppm. Therefore, the spray temperature is kept at not: or more, preferably at 14 (rc or more, and the removal rate of § 〇 3 can be improved. [Brief Description] Fig. 1 shows the exhaust gas in the first embodiment of the present invention. Fig. 2 is a schematic view showing an exhaust gas treatment device according to a second embodiment of the present invention. 105794.doc • 23 - 1280152 Fig. 3 is a schematic view showing a modification of Fig. 2. Fig. 4 is a view showing A schematic diagram of the test apparatus for performing the S03 removal test. Fig. 5 is a graph showing the test results of the removal of S Ο 3. Fig. 6 is a graph showing the test results of the S03 removal.
[Description of main component symbols] ΙΑ,1B 3 5 7 9 10 11 13 15 17 20 22 24 , 109 24a , 40a 24b , 40b 24c 26 28 30 , 46 , 56 Exhaust gas treatment unit boiler flue denitration unit air heater fan Dry electronic dust collector wet desulfurization device dielectric gas cleaning device chimney absorbent sprayer filling layer storage
NaOH solution supply mechanism Air supply mechanism Limestone supply mechanism Absorbent supply pump Drainage pipe Extraction pipe 105794.doc -24- 1280152
32, 48,58 Air pump 35A,: B, C, 115 Dissolved salt sprayer (spraying equipment) 38 Second wet desulfurization unit 40 Second storage unit 42 Second absorbent supply pump 44 Second absorbent sprayer 50 third wet desulfurization device 52 branch pipe 54 third storage portion 100 test device 101 LPG furnace 103 cooling tower 105 wet electronic dust collecting device 107 S03 supply mechanism 1 111 pump 113a, 113b water atomizer Tl-1, 2,3 temperature sensor SI, S2, S3 so3 concentration sensor I05794.doc -25

Claims (1)

1280152 X. Patent application scope: 1 · An exhaust gas treatment device for removing pollutants such as sulfur trioxide, hydrogen fluoride, hydrogen chloride, silver chloride, hydrogen sulfide, sulfurized carbon monoxide and the like contained in combustion exhaust gas, wherein a spray mechanism is provided And spraying an aqueous solution containing a dissolved salt of a vapor, a hydroxide, a sulfate or a carbonate of any one of Na, K, Mg, and Ca in the flue through which the combustion exhaust gas flows. 2. The exhaust gas treatment device according to claim 1, wherein the wet gas desulfurization device is provided, and the aqueous solution is used as the desulfurization wastewater of the wet desulfurization device. 3. The exhaust gas treatment device according to claim 1, wherein the outlet temperature of the spray means is 130 ° C or more, preferably 140 ° C or more. 4. The exhaust gas treatment device of claim 1, wherein the air heater has an air heater that heats air supplied to the combustion furnace by heat obtained from the combustion exhaust gas, and the spray mechanism is disposed on the air heater The upstream side.
5. The exhaust gas treatment device of claim 1, wherein: the air heater has an air heater that heats the air supplied to the combustion furnace by heat obtained from the combustion exhaust gas, and an electronic dust collecting device disposed on the air heater On the downstream side, the spray mechanism is disposed between the air heater fish σσ丹上途雷早尘尘装置. Item 6. The exhaust gas treatment device of claim 1, wherein: the air heater is provided by an electric dust collector, which is obtained by heating from the exhaust gas, and is supplied to the 105794.doc 1280152 electronic dust collecting device. a downstream side of the air heater, and a wet desulfurization device disposed on a downstream side of the electronic dust collecting device, wherein the spray mechanism is disposed on the electronic dust collecting device and the wet desulfurization device In the vicinity of the wet desulfurization device, the exhaust gas treatment device of claim 1, wherein: the two gas heaters heat the air supplied to the combustion furnace by the heat obtained from the exhaust gas, the electrons A dust collecting device is disposed on a downstream side of the air heater, and a wet desulfurization device is disposed on a downstream side of the electronic dust collecting device, wherein the spray mechanism can be disposed at any two of the following three places: An upstream side of the air-rolling heater; between the air heater and the electronic dust collecting device; and the electronic dust collecting device and the wet desulfurization device And nearest to the apparatus of a wet desulfurization.
8. The exhaust gas treatment device of the request, comprising a wet electronic dust collecting device or a dielectric gas cleaning device. Six a gas treatment method, which is a method for removing exhaust gas contained in three parts of the combustion exhaust gas: ratification of strontium, hydrogen chloride, silver chloride, hydrogen sulfide, and sulfurized-oxygen stone ruthenium, wherein the hemisphere contains Na, K, a sulfate or a carbonate is an aqueous solution of a chloride or a hydroxide dissolved salt of Mg Ca in the flue through which the combustion exhaust gas flows. 105794.doc
TW94137539A 2005-04-26 2005-10-26 Exhaust gas treatment system and exhaust gas treatment method TWI280152B (en)

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CA2768184A1 (en) * 2009-07-16 2011-01-20 Babcock & Wilcox Power Generation Group Inc. Redox method for capture of total gaseous mercury by wet fgd
CN102343213B (en) * 2011-10-13 2013-07-03 中冶赛迪工程技术股份有限公司 Process and system for treating strong brine with flue gas desulfurizing device
TWI507685B (en) * 2013-01-14 2015-11-11 Univ Fooyin Nitric oxide radiosonde
CN103861438B (en) * 2014-02-22 2016-03-09 浙江大学 The system and method for deep removal coal-fired flue-gas oxysulfide
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