JP3265328B2 - Electrode device for carbon dioxide generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, the cultivation of aquatic plants and the cultivation of algae using photosynthesis in water,
The present invention relates to a carbon dioxide gas generating electrode device suitably used in a field that requires dissolving carbon dioxide gas in a liquid, such as performing tissue culture of animals and plants by controlling H.

[0002]

2. Description of the Related Art When cultivating aquatic plants or synthesizing algae in an aquarium, carbon dioxide gas required for photosynthesis must be supplied and dissolved in water. The supply of the carbon dioxide gas to the water tank is generally performed via a carbon dioxide gas cylinder installed outside, but it is difficult to uniformly supply the carbon dioxide gas at a slow flow rate of 10 ml / min or less by this method. In order to grow ornamental aquatic plants, a method has been adopted in which carbon dioxide is sealed in a diffusion tube with one end open to water, and the carbon dioxide is dissolved in the liquid by gas-liquid contact at the open end. However, there is a disadvantage that the control of the stop and the control of the supply speed cannot be performed.

One of the present applicants has proposed a mechanism for automatically supplying carbon dioxide gas without relying on an external supply source such as a cylinder in order to solve such a problem. Has developed an apparatus for supplying dissolved carbon dioxide gas for electrolyzing water using carbon as an anode, and has already proposed it (Japanese Patent Application Laid-Open No. 6-154760). In the present invention, as a specific embodiment, an anode made of a carbon rod is inserted in a non-contact state into a cathode member formed of a tubular stainless steel perforated pipe and fixed to an upper terminal (FIG. 2). According to this structure, the anode carbon rod and the cathode can be compactly integrated, and the dissolved carbon dioxide gas generated at the anode and the gaseous hydrogen formed at the cathode can be discharged from the hole formed at the cathode member through the hole formed at the cathode member. Since it is automatically supplied to the inside, the carbon dioxide gas can be safely and efficiently dissolved in the liquid.

[0004]

However, when the electrolysis operation is continued at a constant current using the carbon dioxide gas generating electrode device having the above structure, the voltage between both electrodes is increased even though a considerable amount of anode carbon remains. In some cases, the temperature gradually increased, and finally the current stopped flowing between the poles, and the electrolysis stopped. The present inventors have conducted repeated studies to elucidate the cause, and found that in the above-described conventional structure, a columnar anode carbon rod having the same diameter was placed inside a cylindrical cathode pipe having the same inner diameter in the longitudinal direction. In a relationship where the anode carbon is inserted in a parallel non-contact state so as to be constant, the consumption of anode carbon near the upper part directly connected to the terminal predominantly progresses, and the degree of insulation increases locally, It was clarified that the anode carbon was based on the phenomenon of remaining unreacted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a stable carbon dioxide gas for a long period of time by electrolysis operation with a constant current. An object of the present invention is to provide a gas generating electrode device.

[0006]

According to the present invention, there is provided an electrode device for generating carbon dioxide gas according to the present invention, comprising: an anode carbon rod having an upper end fixed to a terminal; In a carbon dioxide gas generating electrode device having a structure including a cathode plate provided so as to face each other, as the distance between the anode carbon rod and the cathode plate increases from the bottom to the top.
So that the distance between the anode carbon rod and the cathode plate increases gradually.
It is referred to as relative and features of the configuration that was continuously wide as it goes from the bottom to top.

[0007] In the present invention, the form in which the anode carbon rod and the cathode plate face each other in a non-contact state means that the cathode plate is provided around the anode carbon rod at intervals so as to cover the entire circumference thereof. And a mode in which a cathode plate is disposed at both sides of an anode carbon rod at intervals, and a mode in which an anode carbon rod and a cathode plate are disposed facing each other at intervals.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a carbon dioxide gas generating electrode device according to the present invention in which a cathode plate is provided around an anode carbon rod at intervals so as to cover the entire circumference thereof. In the partially cut-away side cross-sectional view, 1 is an anode carbon rod vertically suspended at the center, 2 is in a non-contact state with the anode carbon rod 1, and is expanded in a tapered shape toward the upper part. The installed cathode plate. The cathode plate 2 is installed so as to cover the entire circumference of the anode carbon rod 1, and a plurality of openings 3 are formed on a side surface thereof. The upper end of the anode carbon rod 1 is connected to a conductive lead wire 5 through a terminal portion 4, and a portion including the terminal portion 4 is hermetically covered with a rubber waterproof cover 6. A plastic insulating spacer 7 is interposed between the lower part of the anode carbon rod 1 and the bottom of the cathode plate.
The upper positions of the anode carbon rod 1 and the cathode plate 2 having a large distance between the poles are fixed by a fixing member 8 made of plastic. 9
Is a lead wire fixed to the upper end of the cathode plate 2.

In the apparatus shown in FIG. 1, a columnar or prismatic anode carbon rod is used. When the anode carbon rod has a columnar shape, as shown in FIG.
Is designed to have a cylindrical shape and enclose it around the anode carbon rod 1 at intervals, and when the anode carbon rod has a prismatic shape, the structure shown in FIG. Like cathode plate 2
Are designed to have the same rectangular tube shape and enclose the anode carbon rod 1 at intervals.

In the above structure, the opening 3 provided on the side surface of the cathode plate 2 for degassing is provided with a plurality of circular holes at equal intervals on the side surface of the cathode plate 2 as shown in FIG. As shown in FIG. 4, the cathode plate 2 can be vertically divided into two to form an opening gap, or can be formed as a plurality of slit holes as shown in FIG. Further, a circular hole and a slit hole may be formed in combination, and a metal plate having an infinite number of through holes formed on the entire surface, such as a wire netting or a punched metal, can of course be used. However, when a columnar or prismatic anode carbon rod is used, the most effective shape of the opening 3 is that the opening 3 of the through hole is formed at the top and bottom of the cylindrical cathode plate 2 as shown in FIG. In this configuration, the hydrogen gas generated on the cathode surface and the dissolved carbon dioxide gas generated on the anode surface by natural convection smoothly flow out of the upper hole, so that it is more smoothly arranged. It is possible to carry out various electrolysis operations.

FIG. 7 is a side sectional view showing an embodiment in which a cathode plate is disposed at both sides of an anode carbon rod with a space therebetween. In this structure, a plate-shaped anode carbon rod 1 is suspended from the center, and a plate-shaped cathode plate 2 is arranged on both sides so as to expand toward the top in a non-contact state. Therefore, the cross section along the line AA in FIG. 7 is as shown in FIG.
All are open except for the interposition of a plate-like cathode plate.

FIG. 9 is a side sectional view showing an embodiment in which the anode carbon rod and the cathode plate are installed facing each other with a space therebetween. The structure is such that an insulating mesh container 10 such as a plastic basket is formed so that a plate-shaped carbonaceous cathode plate 2 having the same material and the same shape as the plate-shaped anode carbon rod 1 expands upward.
Is fixedly disposed on the inner wall, and there is no anode carbon rod in the center. Therefore, the cross section taken along the line AA in FIG. 9 is as shown in FIG. 10, and the portions except the anode carbon rod 1 and the cathode plate 2 of the same shape facing each other are surrounded by the insulating mesh container 10.

In the present invention, the anode carbon rod 1 and the cathode plate 2
As a form in which the distance between and is relatively and continuously widened from the lower part to the upper part, as shown in FIGS. In addition to being vertically suspended at the center of a cylindrical or square cylindrical cathode plate 2 formed in an inverted truncated pyramid shape that expands toward the top, the center of the cylindrical cathode plate 2 having the same diameter in the vertical direction It is also possible to adopt a structure in which a conical anode carbon rod 1 whose upper part is thinner and gradually becomes thicker toward the lower part is suspended. In FIG. 8 as well, a structure can be designed in which the cathode plates 2 on both sides are arranged in parallel, and a reversely tapered plate-like anode whose wall thickness continuously increases toward the bottom is arranged at the center thereof. . However, in order to stably generate carbon dioxide gas continuously, it is effective to adopt the illustrated structure in which the cathode plate is inclined with respect to the anode .

In particular, the distance between the poles of the anode carbon rod 1 and the cathode plate 2 is made equal at the same cross-sectional position, and the gap (W ₁ ) between the upper end side surface of the anode carbon rod 1 and the inner surface of the cathode plate 2
Between the lower end of the anode carbon rod 1 and the inner surface of the cathode plate 2
Difference _{(W 2) (W 1 -W} 2) is, it is preferable to provide the inclined surface as fall within the scope of 1.0 to 5.0 mm. When the gap is out of the gap range, the degree of consumption of the anode carbon rod does not progress uniformly from the lower end portion, and the electric resistance near the upper end increases, resulting in a phenomenon that the utilization efficiency of the anode carbon rod deteriorates. The gap (W ₂ ) between the lower end side surface of the anode carbon rod 1 and the inner surface of the cathode plate 2
Is preferably set in the range of 0.5 to 4.5 mm.

The anode carbon rod 1 used in the present invention is made of graphite, glassy carbon, or other various carbonaceous materials using coke, activated carbon, carbon black, thermosetting resin, or the like as a carbon source. There is no limitation. However, for the purpose of the present invention, 35 to 70% by weight of activated carbon, 15 to 50% by weight of kaolin-based clay, 5 to 10% by weight of graphite and 3 to 5% by weight of carboxymethylcellulose are blended and kneaded with water to obtain a predetermined shape. After being formed into a non-oxidizing atmosphere, a carbonaceous material produced by performing a carbonization treatment in a temperature range of 900 to 1200 ° C. is preferably used. On the other hand, the cathode plate 2
Is made of a metal plate especially when the structure shown in FIG. 1 or 7 is used. As a material of the metal plate, for example, a conductive metal such as copper, iron or nickel can be used, but stainless steel having particularly excellent corrosion resistance is preferably used.
However, in the case of using a plate-shaped cathode plate 2 having the same shape as the plate-shaped anode carbon rod 1 as shown in FIG. 9, it is preferable that the cathode plate 2 is formed of the same carbon material as the anode carbon rod 1. With this configuration, it is possible to switch the polarity of the positive electrode at predetermined time intervals or to alternately use the front and back of the electrode plate.

The carbon dioxide gas generating electrode device of the present invention basically has a compact structure in which an anode carbon rod whose upper end is fixed to a terminal portion and a cathode plate face each other in a non-contact state and are integrated. It is set suspended in an aquarium with aquatic plants and algae, and is operated by applying a predetermined current between the negative and positive electrodes. At this time, in a conventional structure in which a columnar anode carbon rod having the same diameter is inserted into a cylindrical cathode pipe having the same inner diameter in the length direction in a parallel non-contact state such that the distance between the poles is constant, The consumption of the anode carbon near the upper part directly connected to the surface predominantly progresses and the degree of insulation is increased, and the lower anode carbon is almost completely consumed, the electrolysis is terminated, and the utilization efficiency of the anode carbon is reduced.

On the other hand, according to the present invention, the distance between the anode carbon rod and the cathode plate increases from the lower part to the upper part.
The distance between the anode carbon rod and the cathode plate is designed to be relatively and continuously widened from the bottom to the top so that it gradually increases. The distance between the anode carbon rod and the cathode plate is longer than that of the lower part, so that the consumption of the anode carbon rod in the lower part where the distance between the poles is shortest progresses fastest. It exhibits a continuous gradual degree of wear in which wear is gradually reduced. For this reason, the wear always progresses from the lower part in a very balanced manner as a whole. By this action, the electrolysis is stably performed for a long time, and a constant amount of carbon dioxide is continuously generated.

In particular, the distance between the poles of the anode carbon rod and the cathode plate is made equal at the same cross-sectional position, and the gap (W ₁ ) between the upper end side surface of the anode carbon rod and the inner surface of the cathode plate and the lower end of the anode carbon rod Difference (W ₁ −W ₂ ) in gap (W ₂ ) between the inner surface of the cathode and the inner surface of the cathode plate
Is set in the range of 1.0 to 5.0 mm, the above function is more effectively exhibited. In addition, when a metal cylindrical cathode plate is used, if through-hole openings formed on the surface are arranged at the upper and lower horizontal positions of the metal cylinder, hydrogen or carbon dioxide gas is introduced into the cylindrical cathode member by convection action. Does not stay, and efficient dissolution of carbon dioxide gas can be promoted. Furthermore, in a structure in which a plate-shaped anode carbon rod and a plate-shaped cathode plate of the same carbonaceous material are used as a counter electrode, the polarity is switched at regular time intervals, or the electrodes are worn by alternately turning the front and back of the plate to face each other. Of the electrodes, effective use of electrodes, simplification of the structure, and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the illustrated embodiments. However, the present invention is not limited to these examples.

Example 1 As shown in FIG. 1, a columnar anode carbon having the same diameter
The rod 1 has an opening 3 having a large number of through holes formed in the side surface.
Inverted frustoconical metal cathode plate formed of stainless steel plate
For generating carbon dioxide with a structure inserted in the center of 2 in a non-contact state
An electrode device was manufactured. The upper end of the anode carbon rod 1 is terminating
To the insulated lead wire 5 through the
The area including the terminal part 4 is densely covered with a waterproof cover 6 made of rubber.
Covered in a closed state, between the lower part of the anode carbon rod 1 and the metal cathode plate 2
Is provided with an insulating spacer 7 made of plastic. Sun
The pole-to-pole distance between the pole carbon rod 1 and the metal cathode plate 2 must be the same
At the same interval, and the side of the upper end of the anode carbon rod 1.
(W)₁) And lower end of anode carbon rod 1
(W)_Two) And the difference (W ₁−
W_Two) Is 2.0 mm, and the distance between poles is large.
The upper positions of the pole carbon rod 1 and the metal cathode plate 2 are made of plastic.
Is fixed by the fixing member 8.

The anode carbon rod 1 was manufactured as follows. Particle size 53-140 μm, specific surface area 1570 m ² / g,
60% by weight of coconut shell activated carbon (manufactured by Mitsubishi Kasei Co., Ltd., "Diasoap F") having an iron content of 0.1% by weight or less, 25% by weight of kaolin clay (manufactured by Kyoritsu Ceramics Co., Ltd.), graphite powder 1
0% by weight and 5% by weight of carboxymethylcellulose were mixed, and 80 parts by weight of water was added to 100 parts by weight of the mixture, followed by thorough kneading. The kneaded material is extruded into a cylindrical shape by a plunger type extrusion molding device, dried at a temperature of 50 ° C. to cure the binder component, and then transferred to a firing furnace maintained in an argon gas atmosphere, and heated at a rate of 100 ° C./hr. The temperature was raised to 1000 ° C. at a heating rate, and calcined at this temperature for 10 hours. This carbon rod was subjected to surface processing to obtain an anode carbon rod 1 having a diameter of 15 mm and a length of 100 mm.

Each of the above carbon electrode devices for generating carbon dioxide gas is
It is installed so that it is immersed in a freshwater aquarium tank in a suspended state.
The electrolysis operation was performed under the conditions of mA and anode current density of 2.8 mA / cm ² until the voltage between both electrodes became 10 V. After the start of the electrolysis, measurement was performed with a commercially available dissolved carbon dioxide reagent for freshwater (manufactured by Tetra), and it was confirmed that carbon dioxide gas was generated stably. In this case, electricity can be supplied for 38 days, and the amount of electricity is 3
At 98 × 10 ³ coulombs, the current during the energization time was stable without fluctuation over time.

Example 2 A carbon rod made of the same material as in Example 1 was machined into
5mm, 100mm and 150mm length cylindrical anode carbon rod, and 150mm length in rectangular cross section (15mm width, 5mm thickness)
Was prepared. Using these anode carbon rods, a carbon electrode device for carbon dioxide generation having the same structure as in Example 1 was assembled. When a plate-shaped anode carbon rod was used, the metal cathode plate was also formed in a rectangular cylindrical shape. Anode carbon rod 1
The distance between the poles of the anode and the metal cathode plate 2 is made equal at the same cross section, and the interval (W ₁ ) between the upper end side surface of the anode carbon rod 1 and the inner surface of the metal cathode plate and the lower end side surface of the anode carbon rod 1 The difference (W ₁ −W ₂ ) between the distance (W ₁ −W ₂ ) and the distance (W ₂ ) between the inner surface of the metal cathode plate and 0.
The electrolysis operation was performed under the same conditions as in Example 1 while varying the range from 5 to 7.0 mm. Measure the amount of current in this case,
The results are shown in Table 1 in comparison with the (W ₁ −W ₂ ) difference.

[0024]

[Table 1]

From the results shown in Table 1, the difference (W ₁ −W ₂ ) is 0.5
In the case of mm and 7.0 mm, the amount of electricity was reduced.
In the range of 5.0 mm, it was stable at a high level of current, and it was confirmed that the anode carbon rod was uniformly consumed while the effective electrolysis operation proceeded.

Example 3 In Example 1, the openings 3 of the metal cathode plate 2 were formed as a row of circular through holes at the upper and lower horizontal positions as shown in FIG. Example 1 except that this cathode member was used
When the electrode device for carbon dioxide gas generation was assembled and electrolysis operation was performed in the same manner as described above, the efficiency of carbon dioxide gas generation was higher than when a large number of through holes were formed on the entire side surface of the metal cathode plate, and the anode carbon rod was It was confirmed that the life was prolonged.

Example 4 A carbon rod made of the same material as in Example 1 was machined to a width of 15 mm.
A plate-shaped anode carbon rod having a thickness of 5 mm, a thickness of 5 mm and a length of 150 mm was prepared. As shown in FIG. 9, a carbonaceous cathode plate 2 having the same material and shape as the anode carbon rod 1 was installed facing the plastic insulating mesh container 10 which expands upward. In this case, the difference between the distance between the distance (W ₁₎ and the lower end portion side surface and the metal cathode plate the inner surface of the cathode carbon rod 1 and the upper end portion side surface and the metal cathode plate the inner surface of the anode carbon rod ₁ (W ₂₎ (W 1
−W ₂ ) was set to 2.0 mm.

The electrolysis operation was performed at 100 mA by switching the anode and the cathode every 30 minutes using the above-mentioned electrode apparatus for generating carbon dioxide gas. After the start of the electrolysis, measurement was performed with a commercially available dissolved carbon dioxide reagent for freshwater (manufactured by Tetra), and it was confirmed that carbon dioxide gas was generated stably. During the operation, when the voltage between the electrodes exceeded 10 V, the anode plate and the cathode plate were turned over to face each other, and the electrolysis operation was resumed. As a result, the voltage between the electrodes dropped to 5 V. The voltage between the poles is again 10
As a result of observing the surface state of both electrodes at a point exceeding V, it was confirmed that the entire surfaces of both carbon plates were uniformly consumed.

[0029]

As described above, according to the electrode apparatus for generating carbon dioxide gas according to the present invention, the electrolysis is stably performed for a long time, and a constant amount of carbon dioxide gas can be continuously generated. It becomes possible. Therefore, the anode carbon can be uniformly consumed to the end without causing troubles such as the stoppage of the electrolysis operation, and the utilization efficiency can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a partially cut-away side sectional view of a carbon dioxide gas generator using a columnar or prismatic anode carbon rod according to the present invention.

FIG. 2 shows a case where a cylindrical anode carbon rod is used.
FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 3 shows a case where a prismatic anode carbon rod is used.
FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 4 is an external view of a carbon dioxide gas generator according to the present invention in which a metal cathode plate having an opening portion divided into two vertically divided parts is installed.

FIG. 5 is an external view of a carbon dioxide gas generator according to the present invention in which a metal cathode plate having a slit-shaped opening is installed.

FIG. 6 is an external view of a carbon dioxide gas generator according to the present invention in which a metal cathode plate having openings formed as a row of circular through holes is provided at upper and lower horizontal positions.

FIG. 7 is a side sectional view of a carbon dioxide gas generator using a plate-shaped anode carbon rod according to the present invention.

8 is a sectional view taken along line AA of FIG. 7 when a plate-shaped anode carbon rod is used.

FIG. 9 is a side sectional view of a carbon dioxide gas generator using the same cathode plate as the plate-like anode carbon rod according to the present invention.

FIG. 10 is a cross-sectional view taken along line AA of FIG. 9 when a plate-shaped anode carbon rod is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode carbon rod 2 Cathode plate 3 Opening 4 Terminal part 5 Insulated lead wire 6 Waterproof cover 7 Insulating spacer 8 Fixing member 9 Lead wire 10 Insulated mesh container

Continuation of the front page (56) References JP-A-2-301582 (JP, A) JP-A-6-154760 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25B 1 / 00-15/08 C01B 31/20 C02F 1/46

Claims (7)

(57) [Claims] 1. An electrode device for generating carbon dioxide gas having a structure comprising an anode carbon rod having an upper end portion fixed to a terminal portion and a cathode plate installed so as to face the anode carbon rod in a non-contact state. An electrode device for generating carbon dioxide gas , wherein a distance between an anode carbon rod and a cathode plate is relatively and continuously increased from a lower portion to an upper portion. 2. A cylindrical or prismatic cathode which expands upward so as to enclose the entire periphery of a columnar or prismatic anode carbon rod vertically suspended at the center in a non-contact state. The electrode device for generating carbon dioxide gas according to claim 1, wherein the plate is provided around the plate. 3. A plate-like cathode plate which is spread toward the upper side so as to face in a non-contact state is disposed on both side surfaces of a plate-like anode carbon rod vertically provided at a central portion. An electrode device for generating carbon dioxide as described in the above. 4. The electrode device for carbon dioxide gas generation according to claim 1, wherein a cathode plate of the same material and the same shape as the plate-like anode carbon rod is installed facing each other so as to expand upward without contact. 5. The distance between the anode carbon rod and the cathode plate is made equal at the same cross-sectional position, and the gap (W ₁ ) between the upper end side surface of the anode carbon rod and the inner surface of the cathode plate and the distance between the anode carbon rod and the cathode plate The difference (W ₁ −W ₂ ) in the gap (W ₂ ) between the lower side surface and the inner surface of the cathode plate
2. The electrode device for carbon dioxide gas generation according to claim 1, wherein the distance is set in a range of 1.0 to 5.0 mm. 6. The carbon dioxide generating electrode device according to claim 2, wherein the cathode plate is made of a conductive metal having an opening on a side surface. 7. The electrode device for generating carbon dioxide gas according to claim 6, wherein a plurality of openings are provided as through holes at horizontal positions above and below the cathode plate.