WO2003082445A1

WO2003082445A1 - Method of decontaminating waste gas and apparatus therefor

Info

Publication number: WO2003082445A1
Application number: PCT/JP2003/002424
Authority: WO
Inventors: Masanori Tashiro
Original assignee: Masanori Tashiro
Priority date: 2002-03-29
Filing date: 2003-03-03
Publication date: 2003-10-09
Also published as: AU2003211446A1; JP2003284919A; JP3901559B2

Abstract

Electrolysis of sea water is performed so as to form an alkali solution and an acid solution. Waste gas to be treated is subjected to gas-liquid contact with the acid solution, and then to gas-liquid contact with the alkali solution. Waste gas decontamination apparatus includes at least one gas-liquid contact means (1) for effecting gas-liquid contact between waste gas to be treated and a treatment solution and an elecrolyzer (16) capable of electrolyzing a salt water into an alkali solution and an acid solution. The at least one gas-liquid contact means (1) is provided with an inlet for waste gas to be treated (5) at an upstream side thereof and provided with an outlet for treated waste gas (6) at a downstream side thereof. At least one gas-liquid contact zone (3A, 3B) arranged thereinside is provided with acid solution spraying means (4A) for spraying the above acid solution or alkali solution spraying means (4B) for spraying the above alkali solution.

Description

Technical Field Exhaust gas purification method and its device

The present invention relates to an exhaust gas purification method and an apparatus therefor, and more particularly to an exhaust gas purification method for purifying exhaust gas from boilers and other combustion equipment of a power plant disposed near the coast using seawater and an internal combustion engine of a ship operating in the ocean. It concerns the device.

Background art

In general, fossil fuels are used in internal combustion engines, burners, and other combustion equipment, and NO x, SO x, CO x, dust particles, etc., contained in exhaust gas and smoke emitted by the combustion emit environmental pollution and global warming. It is one of the causes of the change. In order to solve this problem, various proposals have been made, such as fuel treatment, combustion improvement, and exhaust gas treatment using a catalyst. Exhaust gas from land vehicles has been improved to some extent.

However, if these measures are applied to marine engines, boilers, and heating equipment in boilers and heating furnaces that use light oil or heavy oil as fuel, the amount of emissions and fuel consumption is overwhelmingly larger than that of land vehicles. Therefore, there is a problem that the production cost / operating cost increases significantly, and it is not practical from an economic viewpoint. For this reason, in this type of internal combustion engine and combustion equipment, it is recommended to use a fuel with low sulfur content instead of the inexpensive ultra-low-quality oil with high sulfur content and residual carbon content. Is the current situation.

However, although the emission regulations for NO x and SO x specified in ships in January 2000 have not yet come into effect, the use of low-sulfur fuel alone cannot achieve the emission standards, and However, the low-sulfur fuel is not only expensive than ultra-low-quality oil, but also is not a drastic solution. In the case of an internal combustion engine such as a diesel engine, the low-sulfur fuel is located between the piston ring and the cylinder liner. A new problem has been identified that the engine is severely damaged by friction and wear.

On the other hand, a method of using seawater as S 0 ₂ absorbent have been proposed as an exhaust gas purification method (TOKERUDE A. "Seawater used as S02 removal agent" Modern Power system s, pp-21, 23, 25, 1989 and NYMAN GBG "Seawater scrubbing removes S02 from refinery flue gases" Oil & Gas Journal vol. 89, No. 26, pp52-54, 1991). These methods, and the portion of the seawater is introduced into scrubber contacting gas and liquid from the condenser to absorb the S 0 ₂ present in the flue gas, and mixing the resulting acidic seawater with seawater from the condenser after, which was oxidized s 0 ₂ converts the sulfate I O emissions is a natural component of sea water by Eareshiyon, after saturation of oxygen in the liquid, is intended to discharge into the sea. The method of this has the advantage that it most removed so ₂ in the flue gas, other sulfur compounds H ₂ S contained in the flue gas, COS, CS ₂ and other components, NOx, COx, and dust particles There is a problem that cannot be dealt with.

As a means to solve this problem, the present inventor has developed a marine flue gas desulfurization and denitration system in collaboration with Osamu Nishida and others (Osamu Nishida, Yoshinori Azu, Masanori Tashiro et al. Development of Denitration System ”, Kansai Chapter, 76th Annual Meeting, Lecture Paper No. 014-1, 14-9-14_10, published by The Kansai Chapter of the Japan Society of Mechanical Engineers). This marine flue gas desulfurization and denitration system has a scrubber with an exhaust gas inlet at the top and an exhaust port at the bottom of the side wall, and a seawater electrolyzer that electrolyzes seawater to produce an alkaline solution and an acidic solution. A spray nozzle is disposed inside the scrubber, and an alkaline solution or an acid solution generated by the seawater electrolysis apparatus is sprayed onto the exhaust gas to be treated, which falls from the top of the scrubber, through the spray nozzle. A flue gas desulfurization and denitration system for marine flue gas that has been brought into liquid contact has been developed. This equipment pumps seawater with a pump, filters it, then electrolyzes it to produce an alkaline solution and an acidic solution, and sprays the generated alkaline solution into a scrubber to neutralize sulfur oxides. it is obtained by an acidic solution generated in positive electrode chamber to be sprayed into the scrubber to oxidize NO to N0 ₂ by treatment of nitrogen oxides.

In this apparatus, the pH value of the Al force Li solution can almost 100% reduction of S0 ₂ if around 10, also up to 75% CO and NO X are each, although effects are obtained can be reduced 95%, As a whole, C 0 X and N 0 X achieved a reduction effect of less than half, and it was necessary to further increase the processing capacity.

In order to solve this problem, the present inventor has used the electrolysis tank itself as an exhaust gas treatment tank in cooperation with Shuji Nishida and the like, and configured the electrolysis tank integrally with a scrubber. The exhaust gas to be treated is introduced into the scrubber, and seawater is sprayed into gas-liquid contact with the scrubber. The exhaust gas to be treated by the scrubber is mixed with the alkaline liquid generation chamber partitioned by the diaphragm of the electrolysis tank and the acidic liquid generation. Developed an exhaust gas treatment system that was to be introduced sequentially into the laboratory (Yoshinori Anzu, Osamu Nishida, Masanori Tashiro, et al., "Effluent gas treatment effect by thin-film reaction of seawater electrolyzed water", Marine Engineering Science, Fall 2001) Lecture). The apparatus comprises: a scrubber for spraying seawater into a processing chamber in which an exhaust gas to be processed flows to make gas-liquid contact with the processing chamber; and an electrolytic apparatus integrally formed with the scrubber to generate an alkaline liquid and an acidic liquid. The electrolysis apparatus has two processing chambers which are separated from each other by a diaphragm and have exhaust gas outlets to be treated at the bottom, respectively, and the exhaust gas exhaust port of the scrubber is connected to the outlet at the bottom of one of the processing chambers. In addition, the exhaust gas outlet of the processing chamber is connected to the bottom of the other processing chamber.

However, in this apparatus, since the electrolysis tank and the scrubber are integrated, the occupied volume of the apparatus is inevitably increased, and there are many restrictions on installation on a ship, and the exhaust gas to be treated is placed at the bottom of the processing chamber. Due to the structure of pressurizing into fine bubbles, excess power is required due to large pressure loss. Moreover, in this apparatus, since the solid matter collected by the scrubber is discharged by a belt conveyor, the conveyor drive mechanism is corroded by the acidic liquid used as the cleaning liquid. It became clear that there were problems such as an increase.

Accordingly, the present invention not only the S 0 ₂ can be almost 1 0 Reduction 0%, NO x, it is possible to further reduce the CO x and dust particles, and inexpensive small mold enough to be installed in a ship An object of the present invention is to obtain an exhaust gas treatment method and an apparatus therefor. Disclosure of the invention

According to the present invention, as a means for solving the above problems, basically, seawater is electrolyzed to generate an alkaline solution and an acidic solution, and the exhaust gas to be treated is brought into gas-liquid contact with the acidic solution. After that, it is brought into gas-liquid contact with the alkaline liquid.

In a preferred embodiment of the method of the present invention, at least one scrubber is used as a gas-liquid contact means for bringing a gas and a liquid into contact with each other, and a stream of exhaust gas to be treated flowing from a lower portion to an upper portion of the scrubber is formed. Gas-liquid contact is performed by spraying the acidic liquid and / or the alkaline liquid. [0302] When one scrubber is used as the gas-liquid contact means, at least two stages of gas-liquid contact portions are provided inside the scrubber along the flow direction of the exhaust gas to be treated, and the acid-liquid contact portion is provided on the upstream gas-liquid contact portion. It is preferable that the liquid is sprayed to make gas-liquid contact with the exhaust gas to be treated, and then the alkali liquid is sprayed to a gas-liquid contact portion on the downstream side to make gas-liquid contact with the exhaust gas to be treated.

If there is room in the installation space, two scrubbers were used, which were connected in series along the flow direction of the exhaust gas to be treated, and the acid solution and the exhaust gas treated there were brought into gas-liquid contact in the scrubber on the upstream side. Thereafter, the downstream liquid may be brought into gas-liquid contact with the exhaust gas to be processed by a downstream scrubber. In this case, the gas-liquid contact part of the scrubber does not necessarily have to be one stage, and it goes without saying that two or more stages may be provided.

As the electrolyte to be supplied to the electrolysis apparatus, seawater, artificial seawater, wastewater of seawater used as engine cooling water, condenser condensate, and the like may be used. The acidic liquid supplied to the gas-liquid contact portion of the scrubber is usually set to pH 6 or lower, preferably to pH 2 to 4. The alkaline liquid supplied to the gas-liquid contact portion is usually set to pH 8 or higher, preferably pH 8 to 11, and most preferably ρΗ9.5 to 10.5.

It is preferable that at least the positive electrode chamber and the negative electrode chamber of the electrolysis apparatus are separated by a partition. This is because seawater has a conductivity of 4.5 S / m, which is significantly higher than that of fresh water (0.01 to 0.05 S / m), so if the distance between the electrodes is set to a close distance, for example, lm Then, an electrical short circuit occurs and the electrolytic treatment cannot be continued. Therefore, it is intended to prevent the short circuit by giving the partition walls a certain electric resistance. As the material of the partition walls, it is preferable to use a hydrophilic porous membrane made of a fluorine-based resin such as polytetrafluoroethylene (for example, Teflon (registered trademark)) or a PB0 fiber cloth.

In a preferred embodiment, the gas (H ₂ , Cl ₂ and O ₂ ) generated on one electrode side of the electrolysis apparatus is led to the counter electrode side to reduce the power consumption on the counter electrode side. In addition, hydrogen gas is generated when an alkaline solution is generated. By using this hydrogen gas as fuel for a fuel cell, about half of the power required for electrolysis is recovered. be able to.

In the method of the present invention, first, seawater is electrolyzed to form an alkaline solution and an acidic solution, and the exhaust gas to be treated is brought into gas-liquid contact with the acidic solution. Components with strong oxidizing power (specifically, hypohalite ions (C 10—, Br O—, I 0 ″), reactive oxygen species (0 H radical), and oxidizing gas (Cl) _2, 0 ₂₎₎ is oxidized by reaction with, stable and harmless substances in nature ocean such as (N 0 ₃ -. be converted) into -, S 0 _4.

Then, when is an acidic solution to be treated exhaust gas treated with alkaline solution and gas-liquid contacting, C 0 ₂ to be treated in the exhaust gas hydration generates promoted HCO ions by Al force Li solution, absorption in an alkali solution Is done. Thus, to reduce the emissions concentration in an alkaline solution C 0 ₂ in the atmosphere, then, it is used for neutralization of acidic wastewater.

The method of the present invention includes: at least one gas-liquid contacting unit for bringing the exhaust gas to be treated into contact with the treatment liquid in a gas-liquid manner; and an electrolytic device for electrolyzing salt water to produce an alkaline solution and an acidic solution, The at least one gas-liquid contact means has an inlet for an exhaust gas to be treated on the upstream side, and an exhaust port for the exhaust gas to be treated on the downstream side, and has at least one gas-liquid contact portion disposed therein. It is preferable to carry out the process using an exhaust gas purifying device, which is provided with an acidic liquid spraying means for spraying an acidic liquid or an alkaline liquid spraying means for spraying the alkaline liquid.

As the gas-liquid contacting means, known means such as an absorption tower and a scrubber can be used.The scrubber includes, for example, a spray washing tower, a water jet scrubber, a cyclone scrubber, a venturi scrubber, and the like. Or, they can be used in combination.

In another embodiment of the method of the present invention, the gas-liquid contact means is constituted by a scrubber, the scrubber has at least two gas-liquid contact portions therein, and is upstream in the flow direction of the exhaust gas to be treated. Liquid spraying means for spraying the acidic liquid generated by the electrolytic device on the gas-liquid contact portion on the side, and an Al force for spraying the alkaline liquid generated by the electrolytic device on the gas-liquid contact portion on the downstream side thereof It is preferable to provide a re-liquid spraying means. In another embodiment of the method of the present invention, the gas-liquid contact section of each stage of the scrubber has a liquid storage section for holding the liquid sprayed from the acidic liquid spraying means or the alkaline liquid spraying means. The liquid in the liquid storage section is configured to flow down along the wall surface forming the gas-liquid contact section.

In another embodiment of the method of the present invention, a pretreatment tank is provided between the source of the exhaust gas to be treated and the gas-liquid contact means, and the pretreatment tank is connected to the source of the exhaust gas to be treated at the upper part thereof. The treated exhaust gas inlet is provided with a treated exhaust gas inlet communicating with the lower part of the gas-liquid contact means at the lower part thereof, and the flow direction of the treated exhaust gas from the treated exhaust gas generation source is provided therein. It is preferable to provide a liquid spraying means for spraying the liquid to the surface.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic explanatory view showing an embodiment of an exhaust gas treatment apparatus according to the present invention. FIG. 2 is a schematic explanatory view showing another embodiment of the exhaust gas treatment apparatus according to the present invention. FIG. 3 is a schematic explanatory view showing another embodiment of the exhaust gas treatment apparatus according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

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

As shown in FIG. 1, the exhaust gas treatment device according to the present invention includes a gas-liquid contact device 1 for bringing the exhaust gas to be treated into contact with the treatment liquid in a gas-liquid manner, and an electrolysis device 16. The gas-liquid contact device 1 includes a cylindrical tower main body 2 having two upper and lower gas-liquid contact portions 3Α and 3 内部 inside, and an acid liquid or an alkaline liquid in each of the gas-liquid contact portions 3Α and 3Β. It consists of a scrubber consisting of spray nozzles, 4 mm and 4 mm, for spraying fluid. The tower body 2 has a treated exhaust gas inlet 5 at its lower part and a treated exhaust gas outlet 6 at its upper part.

The treated exhaust gas inlet 5 of the tower body 2 communicates with an upper part of a waste liquid treatment tank 液 disposed therebelow, and the waste liquid treatment tank 7 is connected to a diesel engine or other engine through a treated exhaust gas line 8. It is connected to an exhaust gas source (not shown). A blower 9 is disposed on the treated exhaust gas line 8. Further, the waste liquid in the waste liquid treatment tank 7 is discharged to the ocean via the waste liquid detoxification device 10.

The gas-liquid contact portions 3Α and 3Β of the scrubber are disposed coaxially with the spray nozzles 4Α and 4Β for spraying an acidic solution or an alkaline solution as a treatment solution, and the tower body 2 of the scrubber. Spillover wall 11 1 A, 11 1 た, and the overflow walls 11 A, 11 B The storage sections 12A and 12B for temporarily storing a part of the processing liquid sprayed from the spray nozzles 4A and 4B are formed, and the processing liquid overflowing from the storage section 12 is formed. A gas-liquid contact surface is formed to flow down along the wall surface and make gas-liquid contact. The storage section 12 of the lower gas-liquid contact section 3 is connected to the waste liquid treatment tank 7 through an acidic liquid waste liquid line 13, and a valve 1 disposed in the acidic liquid waste liquid line 13. By controlling 4 A and 14 B, the overflow rate flowing down from the storage section 12 along the overflow wall 11 is maintained substantially constant.

Similarly, the storage section 12B of the upper gas-liquid contact section 3 is discharged to the ocean via an alkaline liquid waste line 15 and a valve provided in the alkaline liquid waste line 15 By controlling 14 B, the overflow rate flowing down from the storage section 12 B along the overflow wall 11 B is maintained substantially constant.

The electrolytic device 16 includes an electrolytic cell 17, a partition 18 that partitions the inside of the electrolytic cell 17 into a positive electrode chamber and a negative electrode chamber, a positive electrode 19 disposed in the positive electrode chamber, and And a seawater supply means 21 for supplying seawater to the positive electrode chamber and the negative electrode chamber, respectively. The positive electrode chamber and the negative electrode chamber are connected to spray nozzles 4 for the gas-liquid contact parts 3A and 3B via an alkaline liquid supply line 22 and an acidic liquid supply line 23 each equipped with a pump. ing.

The partition wall 18 is made of a hydrophilic porous Teflon (registered trademark) film. By interposing the electric resistance of the hydrophilic porous film between the positive and negative electrodes, a short circuit between the electrodes can be prevented and at the same time, the positive and negative electrodes can be prevented. The distance between the two electrodes is shortened so that the device can be downsized.

DC (including pulsating flow) is applied between the positive and negative electrodes, but any source of DC power can be used. Not only fuel cells and storage batteries that generate pure DC, but also DC generators Or an AC generator. When an AC generator is used as a DC power supply, it is needless to say that AC is half-wave rectified or full-wave rectified and then applied between positive and negative electrodes with or without smoothing.

In use, first, seawater is supplied to the electrolysis device 16 and a DC voltage is applied between the electrodes in the electrolysis device 16, and the seawater is electrolyzed and an alkaline liquid (pH 8 to l 1), but acid solution of PH 2 ~ 4 is generated on the positive electrode side Positive electrode side

2 Η ₂ 0 → 0 ₂ + 4 Η + + 4e '

NaCl → Na ⁺ + Cl 2 CV → Cl ₂ + 2 e

CI "+ 2 OH" → CIO- + H ₂ 0 + 2 e "

Cl ₂ + H ₂ 0 + → HCIO + CI "+ H ⁺

HCIO + 2 H ₂₀ → C10 _3- + 5H + + 5e "

Negative electrode side

2 H ₂ 0 + 2e → H ₂ + 2 OH "

The acidic solution is sprayed from the electrolysis device 16 through the acidic solution supply line 23 from the spray nozzle 4 to the lower gas-liquid contact portion of the scrubber, and the alkaline solution is sprayed from the spray nozzle 4 through the alkaline solution supply line 22 through the spray nozzle 4. Is sprayed on the upper gas-liquid contact part.

On the other hand, the exhaust gas to be treated introduced into the waste liquid storage tank via the treated exhaust gas line 8 is first sprayed on the surface of the waste liquid in the waste liquid storage tank, and the dust particles are captured in the liquid. Then, flows into the scrubber, the upstream side, i.e., nitrous oxide contained in contact with the acid liquid in the lower part of the gas-liquid contact portion 3 A to be processed in the exhaust gas (NO, N ₂ 0, SO have CO, etc.) Components with strong oxidizing power (specifically, hypohalite ions (C10 ·, BrO \ 10 "), reactive oxygen species (0H radical), and oxidizing gas (C1 0 ₂ )) it is oxidized by the reaction, and stable in nature harmless substances (.nu.0 ₃ · marine etc., S_〇 ₄ -. dissolution reaction of) is converted to various suboxides are as follows.

i) N0

NO + CIO '→ N0 _2- + 1/2 (Cl ₂ )

NO + l / 20 ₂ → N0 ₂

2 N0 ₂ → N ₂ 0 ₄ ,

_{_{HN0 2 + NaOH → NaN0 2 +}} H 2 0

ii) SOx

S0 ₂ + H ₂ 0 → H ₂ S0 ₃ H ₂ S 0 ₃ + 1/20 ₂ → H ₂ S0 ₄

_{_{H 2 S 0 3 + NaOH →}} Na 2 S0 3 + 2 H 2 0

H ₂ S〇 ₄ + 2 NaOH → Na ₂ S0 ₄ + 2 H ₂ 0

Treated exhaust gas treated with the acid solution, then, downstream of the gas-liquid contact tank 3 enters B, where C 0 ₂ is Al Al force re liquid and gas-liquid contact with the treated flue gas to be sprayed Carbonic acid ions are generated by the reaction with the solution and absorbed and removed by the solution.

C0 ₂ + 2 OH "→ H ₂ C0 ₃ + 1/20 ₂

_{_{H 2 C0 3 + NaOH → NaHC0}} 3 + H 2 0 (pH = 7~8) NaHC0 3 + NaOH → Na 2 C0 3 + H 2 0 (p H = 10~ 13) removing nitrous oxide in this way Exhaust gas is discharged into the atmosphere from the top of the scrubber ^ <o

On the other hand, the acid liquid sprayed on the lower gas-liquid contact part 3 A is collected in the storage part 12, and the acid liquid overflowing from the upper edge thereof flows down along the overflow wall 11, and comes into contact with the gas-liquid part. After being collected in the waste liquid storage tank from the lower end of the overflow wall, it is sent to the waste liquid detoxification device 10 to separate solids and then is disposed of in the ocean. The alkaline liquid sprayed on the upper gas-liquid contact section 3B is collected in the storage section 12, and the alkaline liquid overflowing from the upper edge thereof flows down along the overflow wall 11 while contacting the gas-liquid section. From the lower end of the overflow wall and into the lower gas-liquid contact area 3 A, where the acidic liquid is partially neutralized and collected in the waste liquid storage tank. After C 0 ₂ Ritsuchi liquid collected in reservoir 12 in the upper gas-liquid contact portion 3 B it is mixed with the acidic waste liquid from the waste liquid harmless device 1 0 to neutralize acidic waste liquid is discarded to the ocean. In the above embodiment, the alkali solution and the acid solution are sprayed as they are in the electrolyzer onto each gas-liquid contact portion. However, each solution is provided with a neutralizing buffer such as seawater, It may be sprayed by adding salt water with neutralizing buffer such as artificial seawater or hot water, and spraying an alkali solution and an acid solution while simultaneously spraying the neutralization solution from a different spray nozzle from these solutions. A buffer solution may be sprayed and used together. FIG. 2 shows an exhaust gas purification system according to a second embodiment used for carrying out the method of the present invention, in which a pretreatment device 24 is disposed between an exhaust gas generation source and the gas-liquid contact device 1, and the exhaust gas is discharged. In addition to cooling the dust, dust particles contained in the exhaust gas are removed in advance. This pretreatment device 24 is composed of a co-current scrubber and has gas-liquid contact inside. Equipped with an accelerator 25 and a spray nozzle 4C. The gas-liquid contact promoting material 25 is composed of a single or a plurality of cylindrical or conical members, and the member itself is provided with a large number of holes. Seawater may be directly supplied to the scrubber, or, as shown in the figure, an acidic solution or an alkaline solution generated by the electrolytic device 16 may be supplied and ejected from the ejection nozzle. In the present embodiment, the blower 9 is provided at the exhaust gas outlet 6 to be treated.However, the other configuration and the operation at the time of its use are such that dust particles are sprayed on the liquid surface and trapped in the liquid. The description is omitted because it is the same as that in FIG. 1 except that it is captured by gas-liquid contact instead.

In the second embodiment, an example is shown in which the gas-liquid contact promoting material 25 is provided in a scrubber as a pretreatment device, but the overflow wall of the gas-liquid contact device of the first and second embodiments is described. A gas-liquid contact promoting material having the same structure as that of the gas-liquid contact promoting material 25 may be provided inside the 11 A, 1 IB, that is, on the wall surface where the gas-liquid moves while contacting. . As a result, the gas-liquid contact ¾J rate of the scrano can be increased.

Further, in the above embodiment, the blower 9 is disposed in the exhaust gas outlet 6 to be treated or the exhaust gas line 8 to be treated, but the discharge pressure of the combustion gas such as engine is a pressure in the operation of the gas-liquid contact device 1. It is not always necessary to provide a blower if the loss can be sufficiently exceeded.

Further, a water jet scrubber having a simple structure and easy to use a corrosion-resistant material may be adopted as the pretreatment device 24 instead of the spray scrubber.

FIG. 3 shows a third embodiment of the present invention. The gas-liquid contact device 1 of the present exhaust gas purification system comprises: a tower body 2 for bringing the exhaust gas to be treated into contact with the processing liquid in a gas-liquid manner; It consists of a horizontal flow type scrubber equipped with spray nozzles 4A and 4B for spraying liquid or alkaline liquid. The tower main body 2 is provided with a treated exhaust gas inlet 5 at one end thereof, and is provided with a treated exhaust gas outlet 6 at the other end thereof, and the inside thereof is formed by a baffle plate 30 and a weir plate 31. The first gas-liquid contact part 3A on the upstream side and the second gas-liquid contact part 3B on the downstream side are separated in the flow direction of the exhaust gas, and the acidic liquid is sprayed on the first gas-liquid contact part 3A. A plurality of spray nozzles 4A are provided, and a plurality of spray nozzles 4B for spraying an alkaline liquid are provided in the second gas-liquid contact portion 3B.

If necessary, as shown by broken lines in the figure, the first and second gas-liquid contact portions 3A and 3B A plurality of partition walls 32 are provided, and a single or a plurality of spray nozzles for spraying an alkali solution are provided in each space, so that the exhaust gas introduced into the tower body 2 has an internal space in each gas-liquid contact portion. The space may be meandered in the vertical direction to increase the gas-liquid contact efficiency.

In the present embodiment, the exhaust gas introduced into the first gas-liquid contact portion 3A from the to-be-treated exhaust gas inlet 5 comes into contact with the acidic liquid sprayed to the first gas-liquid contact portion 3A, and the After the particles and suboxides are trapped and removed, they flow into the second gas-liquid contact part 3B, where they come into contact with the alkaline liquid to trap and remove C0X, which is released into the atmosphere from the exhaust gas outlet 6 to be treated. Is done.

On the other hand, the acidic liquid and the alkaline liquid sprayed on the first and second gas-liquid contact sections 3A and 3B are collected at the bottom of each of the gas-liquid contact sections 3A and 3B. Part of the waste liquid stored in 3B passes through the weir plate 31 and flows into the first gas-liquid contact part 3A to increase the pH of the acidic liquid waste, while the remaining alkaline liquid waste Is sent to the filter 33 via the alkaline liquid waste line 15 to neutralize the acidic liquid waste discharged from the acidic liquid waste line 13 to the filter 33. The waste liquid that has been separated into solid and liquid by the filter 33 is disposed of in the ocean as neutralized wastewater.

With this configuration, the present invention can be applied to an extremely small-scale exhaust gas generator such as a small boat.

As apparent from the above description, by adopting the present invention a method and purification device, not only the S 0 ₂ can be almost 1 0 Reduction 0%, NO x, further reducing the CO x and dust particles child Can be. In addition, since the gas-liquid contact portion inside the scrubber can be divided and arranged in multiple stages upward and downward, the installation space can be reduced and the size can be reduced to a level that can be mounted on a ship. In addition, by combining the two types, the gas-liquid fluidized bed and the falling liquid thin-film layer, a sufficient gas-liquid contact reaction can be performed, and the pressure loss can be suppressed to a minimum. Furthermore, since the scrubber is vertical, it can be used as a chimney. In addition, since the scrubber can be separated from other components and connected to the piping, excellent effects can be obtained, such as flexibility in the installation location of the device and reduction of the location restrictions such as the installation space.

Claims

The scope of the claims

1. An exhaust gas purifying method, comprising: electrolyzing salt water to generate an alkaline solution and an acidic solution; bringing the exhaust gas to be treated into gas-liquid contact with the acidic solution;

2. The exhaust gas to be treated is introduced into the lower part of at least one gas-liquid contacting means and discharged from the upper part of the gas-liquid contacting means, and the acidic liquid and the alkaline liquid are respectively introduced into the gas-liquid contacting means. The method according to claim 1, wherein the liquid is sprayed on and brought into gas-liquid contact.

3. As the gas-liquid contact means, a scrubber having at least two gas-liquid contact portions disposed along the flow direction of the exhaust gas to be treated is used, and the acid liquid is sprayed on the gas-liquid contact portion on the upstream side thereof. 3. The method according to claim 2, wherein after the gaseous liquid is brought into contact with the exhaust gas to be treated, the alkaline liquid is sprayed to a gas / liquid contact portion on the downstream side to make gas-liquid contact with the exhaust gas to be treated.

4. As the gas-liquid contact means, at least two scrubbers which are connected in series with each other and have at least one gas-liquid contact portion therein are used, and the at least one scrubber disposed on the upstream side in the flow direction of the exhaust gas to be treated is used. After the acidic liquid is sprayed on the gas-liquid contact part of the scrubber and brought into gas-liquid contact with the exhaust gas to be treated, the alkaline liquid is sprayed on the gas-liquid contact part of at least one scrano on the downstream side. 3. The method according to claim 2, wherein the exhaust gas is brought into gas-liquid contact with the treated exhaust gas.

5. At least one gas-liquid contacting means for bringing the exhaust gas to be treated and the treatment liquid into gas-liquid contact, and an electrolyzer for electrolyzing salt water to produce an alkaline solution and an acidic solution, The gas-liquid contact means has an inlet for the exhaust gas to be treated on the upstream side and an exhaust port for the exhaust gas to be treated on the downstream side, and the acid for spraying the acidic liquid to at least one gas-liquid contact portion provided therein. An exhaust gas purifying apparatus, comprising: a liquid spraying means or a liquid spraying means for spraying the liquid.

6. The gas-liquid contact means comprises a scrubber, and the scrubber has at least two gas-liquid contact portions therein, and the acidic liquid is supplied to the gas-liquid contact portion on the upstream side with respect to the flow direction of the exhaust gas to be treated. The acidic liquid spraying means to be sprayed and the gas-liquid contact area on the downstream side 6. The exhaust gas purifying apparatus according to claim 5, further comprising a liquid spraying means for spraying the liquid.

7. The gas-liquid contact section of each stage of the scrubber includes a liquid storage section for holding the liquid sprayed from the acidic liquid spraying means or the alkaline liquid spraying means, and transfers the liquid in the liquid storage section to the gas-liquid contact section. The exhaust gas purifying apparatus according to claim 5 or 6, wherein the exhaust gas purifying apparatus is caused to flow down along a wall surface that forms the air.

8. A pre-treatment tank is provided between the source of the exhaust gas to be treated and the gas-liquid contact means, and the pre-treatment tank has an inlet for the exhaust gas to be treated connected to the source of the exhaust gas to be treated, and a lower part thereof. The apparatus has a gas exhaust port for communicating with a lower portion of the gas-liquid contacting means, and a liquid spraying means for spraying a liquid in a flow direction of the gas to be treated from the gas generating source. The exhaust gas purifying apparatus according to any one of claims 5 to 7, characterized in that:

9. The exhaust gas purification according to any one of claims 5 to 8, wherein the electrolysis device is divided into a positive electrode chamber and a negative electrode chamber by a partition, and the partition is made of a hydrophilic porous membrane or a PB fiber cloth. apparatus.