JP2000061297A - Carbon dioxide discharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon dioxide discharger by which liq. carbon dioxide is discharged from plural holes provided in a discharge pipe under an appropriate pressure corresponding to the position of the holes. SOLUTION: In the carbon dioxide discharger in which liq. carbon dioxide is introduced into a discharge pipe 4 hung from a ship sailing on the sea and discharged from the discharge pipe 4, an opening 11 for discharging liq. carbon dioxide flowing in the discharge pipe 4 is formed at the lower end of the discharge pipe 4, an outer cylinder 12 forming a storage chamber 13 to store the liq. carbon dioxide discharged from the opening 11 of the discharge pipe 4 is formed at the lower end of the discharge pipe 4 to surround it, and plural discharge holes 14 are vertically formed in a line in the peripheral wall of the outer cylinder 12 to discharge the liq. carbon dioxide stored in the chamber 13 into the sea.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for discharging carbon dioxide, which releases recovered carbon dioxide into the sea and dissolves it in seawater. 2. Description of the Related Art Recently, global warming has become a major problem, and carbon dioxide (CO) having a greenhouse effect, which has been pointed out as a possibility of causing climate change on a global scale, has been pointed out. ₂ ) It has become particularly important to suppress the rise in concentration in the atmosphere. As one of the measures, a concept has been proposed to sequester carbon dioxide from the atmosphere for a long time by collecting and sending carbon dioxide in flue gas discharged from thermal power plants etc. to the ocean, In order to achieve this, it is necessary to ensure that no new environmental impact is caused in the ocean that sends carbon dioxide. The following two types of systems have been proposed as systems for reducing the influence on the marine environment due to carbon dioxide feeding. One of them is a storage type, in which carbon dioxide is concentrated and stored in places such as pits on the deep sea floor to limit the affected area to a specific place and localize it. [0004] Another system is called a dissolution-diffusion type in which carbon dioxide is dissolved in seawater, diluted dilutely and diffused widely to suppress an increase in the concentration of carbon dioxide in seawater. This method is based on the idea that the concentration of carbon dioxide originally dissolved in seawater only increases to some extent. [0005] As a specific method in the dissolution-diffusion type, there is a middle-layer dilution discharge system in which a discharge point of carbon dioxide is moved by a ship to discharge carbon dioxide in a middle layer in the sea. This method will be described with reference to FIGS. FIG. 3 is an explanatory view schematically showing a system of a middle-layer dilution discharge method, and FIG. 4 (a) is an explanatory view schematically showing a state in which carbon dioxide is discharged and diffused from a discharge pipe into the sea in the same method. 4B is an enlarged view of a portion Z in FIG. 4A, and FIG. 5 is an explanatory view showing a state of a droplet formed by discharging carbon dioxide from a discharge pipe. [0006] This mid-level dilution discharge system is based on the land plant 1
Liquefies the carbon dioxide separated and recovered from the combustion exhaust gas by
The liquefied gas is filled in a storage tank 2a and transported by sea to a predetermined sea area on the liquefied gas carrier 2 where the liquid carbon dioxide in the storage tank 2a is transferred to the storage tank 3a mounted on the work boat 3. The liquid carbon dioxide has, for example, a pressure of 6 atm and a temperature of -55 ° C. FIG. 6 is a diagram showing the phase state of carbon dioxide. As can be seen from this diagram, the condition of 6 atm and a temperature of -55 ° C. are conditions under which liquid carbon dioxide can be obtained economically. Work boat 3 has a depth of 200
A discharge pipe 4 made of a very long steel pipe or the like suspended from the sea of 0 m to 2500 m is provided. The discharge pipe 4 has a lower end face closed, and a plurality of discharge holes 5 are vertically spaced in the peripheral wall at the lower end. And are formed in a line.
Then, the liquid carbon dioxide is discharged from the storage tank 3a to the discharge pipe 4
And discharged into the sea from a plurality of discharge holes 5 formed at the lower end of the discharge pipe 4 and arranged vertically. The work boat 3 advances while discharging the liquid carbon dioxide from the hole 5 of the discharge pipe 4 into the sea, thereby moving the discharge point of the liquid carbon dioxide without being limited to a local area, thereby increasing the dilution of the liquid carbon dioxide. . Note that the carrier 2 and the work boat 3 may be different from each other, or may be shared by both. SL is the sea surface. The state of the liquid carbon dioxide discharged from the discharge pipe 4 is assumed as follows from the current knowledge. The liquid carbon dioxide 6 discharged into the sea from the hole 5 of the discharge pipe 4 does not immediately dissolve in the seawater, but in the fluctuating flow field 9 due to the vortex 8 generated and left behind by the discharge pipe 4. Many droplets 7 are dispersed and almost uniformly mixed with seawater. The discharge pipe 4 is inclined rearward in the direction of travel of the ship according to the flow velocity relative to the opposing ocean current, and proceeds while continuously generating a wake vortex having a rotation axis 4 substantially parallel to the pipe axis behind the discharge pipe. Go out. The pattern of the vortex 8 varies depending on conditions such as the shape, surface condition, dimensions and moving speed of the discharge pipe. It is considered that a swirl is generated from both sides and the fluctuating flow field 9 is left behind, in which liquid carbon dioxide and seawater mix. [0008] Then, the carbon dioxide droplet 7 gradually rises in the seawater while being further dissolved in the surrounding seawater from the downstream of the discharge pipe 4. That is, the diameter of the droplet 7 of the liquid carbon dioxide is reduced by being dissolved in the seawater while rising in the seawater. Then, in the process of ascending the droplet 7 to a certain height, all of the liquid carbon dioxide is dissolved into the seawater, and the droplet 7 disappears. [0009] The middle-layer dilution discharge method is approximately 2,000 from the sea surface.
It discharges liquid carbon dioxide in the sea at a depth of from m to 2500 m (middle layer). In other words, when liquid carbon dioxide is discharged in the sea above 2000 m, droplets may reach the sea surface before all of the discharged liquid carbon dioxide does not dissolve in the seawater, and about 2000 m to 25 m
When the liquid carbon dioxide is discharged in the sea at a depth of 00 m, all the carbon dioxide can be dissolved in the seawater before the droplet reaches the sea surface. [0010] As described above, the discharge device employing the middle dilution discharge method is considered to be a very promising device for discharging carbon dioxide to the ocean and isolating it.
This discharge device has the following problems. The liquid carbon dioxide that has flowed down the discharge pipe 4 is discharged into the sea from each of a plurality of discharge holes 5 formed vertically at the lower end of the discharge pipe. Part of the liquid carbon dioxide that has flowed down the inside is first discharged from the discharge hole 5 located at the top, and then the remaining part is discharged from the discharge hole 5 located second from the top. In this way, the liquid carbon dioxide is discharged sequentially from the upper discharge hole 5 to the lower discharge hole 5, and the last remaining liquid carbon dioxide is discharged from the lowermost discharge hole 5. As described above, in the process in which the liquid carbon dioxide is sequentially discharged into the sea from each of the discharge holes 5 arranged from the top to the bottom, a pressure loss is generated every time the liquid carbon dioxide is discharged from each of the discharge holes 5. That is, as the liquid carbon dioxide is sequentially discharged from the discharge holes 5 arranged from the top to the bottom, the pressure to be discharged decreases. By the way, as the position of the vertically arranged discharge holes 5 shifts downward, the depth of the sea corresponding to each discharge hole 5 gradually increases (becomes deeper). As the position of the holes 5 moves from the upper side to the lower side, the pressure applied to the liquid carbon dioxide discharged from each discharge hole 5 gradually increases. In order for the liquid carbon dioxide discharged from each discharge hole 5 to generate droplets in the sea, the pressure corresponding to the pressure applied to the liquid carbon dioxide discharged from the discharge hole 5 according to the position of each discharge hole 5 was determined. The liquid carbon dioxide needs to be released at a pressure in the appropriate range. Therefore, as the position of the discharge hole 5 moves from the upper side to the lower side, the pressure at which the liquid carbon dioxide is discharged from each discharge hole 5 needs to be sequentially increased in accordance with the increase in the pressure applied to the liquid carbon dioxide discharged. There is. However, as described above, the liquid carbon dioxide actually flows in a direction in which the pressure loss due to the discharge from each discharge hole 5 and the pressure change due to the water depth are not balanced, and as the discharge hole 5 is located on the lower side. Since the discharge pressure of the liquid carbon dioxide decreases, the range of the appropriate size corresponding to the position of each discharge hole 5 does not allow the discharge pressure of the liquid carbon dioxide to be obtained. Droplets may not be formed properly and uniformly due to the liquid carbon dioxide discharged into the container. For example, when liquid carbon dioxide is discharged from the discharge hole located on the upper side, the pressure is too high and droplets are sprayed, and in the discharge hole located on the lower side, the pressure is too low and the liquid carbon dioxide is not discharged and the liquid is discharged. Drops may not be formed. The present invention has been made in view of the above circumstances, and a liquid carbon dioxide capable of forming liquid droplets by discharging liquid carbon dioxide from a plurality of discharge holes provided in a discharge pipe at an appropriate pressure corresponding to its position. It is an object to provide a discharge device. According to the present invention, there is provided a carbon dioxide discharging apparatus for sending liquid carbon dioxide into a discharging pipe suspended from a ship sailing at sea into the sea, and from the discharging pipe to the sea. In the discharge device for discharging, an opening is formed at the lower end of the discharge pipe to allow the liquid carbon dioxide flowing inside the discharge pipe to flow out, and the lower end of the discharge pipe surrounds the outer periphery at the lower end of the discharge pipe. An outer cylinder is provided that forms a storage chamber that stores the liquid carbon dioxide flowing out of the opening and flows in a direction opposite to the direction in which the liquid carbon dioxide flows out of the lower end opening, and the liquid carbon dioxide stored in the storage chamber on a peripheral wall of the outer cylinder. A plurality of discharge holes for discharging water into the sea are vertically arranged. FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 schematically shows a discharge device according to this embodiment, and FIG. 2 is an enlarged sectional view schematically showing a liquid carbon dioxide discharge portion of a discharge pipe in the discharge device. The present invention is directed to an apparatus for discharging the liquid carbon dioxide shown in FIGS. 3 to 5 to the ocean by a middle-layer dilution discharge method described above. In FIG. 1, the same parts as those in FIG. 3 are denoted by the same reference numerals. I have. In the figure, 3 is a work boat, 3a is a tank mounted on the work boat 3 for storing liquid carbon dioxide, 4
Is attached to the work boat 3 and suspended under the sea.
This is a discharge pipe that sends the liquid carbon dioxide stored in a from the upper end, flows it, and discharges it into the sea. In the present invention, the following configuration is employed to discharge liquid carbon dioxide to the lower end of the discharge pipe 4.
The discharge pipe 4 has a circular cross section, and has a length that allows it to be suspended from the work boat 3 in the sea at a depth of 2000 m to 2500 m and towed by the work boat 3. No discharge hole is formed in the peripheral wall at the lower end of the discharge pipe 4, and an opening 11 through which the liquid carbon dioxide flowing inside the discharge pipe 4 flows out is formed at the lower end. At the lower end of the discharge pipe 4, an outer cylinder 12 surrounding the outer periphery thereof is provided. The outer cylinder 12 forms a cylindrical body having both ends closed, and its length and diameter surround the discharge hole 4 to form a storage chamber 13 of a predetermined amount, and a predetermined number of discharge holes 14 are formed. The size is set so that it can be formed vertically. For example, the outer cylinder 12 has a diameter of about 1 m and a length of several tens of meters. The outer cylinder 12 is disposed on the same central axis as the discharge pipe 4 so as to surround the lower end of the discharge pipe 4 and is fixed to the discharge pipe 4 by an appropriate means. Discharge pipe 4 is outer cylinder 1
2 is inserted into the outer cylinder 12 through the center of the upper end wall 12a, and the lower end opening 11 thereof is located at a position separated from the lower end wall 12b of the outer cylinder 12 so that the liquid carbon dioxide flows into the lower end wall 12a of the discharge pipe 4. It is made to flow toward. In the space inside the outer cylinder 12 provided in this manner, the accommodating chamber 1 forming a concentric circle around the lower end of the discharge pipe 4 is provided.
The lower end opening 1 of the discharge pipe 4 is formed in the accommodation chamber 13.
1 containing the liquid carbon dioxide flowing out from the lower end 1
It is formed so as to flow in the direction (upward) opposite to the direction (downward) flowing out of the device 1. The peripheral wall portion 12 of the outer cylinder 12
c, a plurality of discharge holes 14 at a plurality of locations in the circumferential direction.
Are formed in a line, in a staggered manner, or in other forms at intervals in the vertical direction. The size and number of the discharge holes 14 are set in consideration of conditions such as the discharge flow rate of liquid carbon dioxide. For example, from the vicinity of the upper end wall 12 a of the outer cylinder 12 to the lower end wall 1
The discharge holes 14 are formed vertically in the vicinity of 2b. The discharge device having the above-described structure is used for the work boat 3
The storage tank 3a mounted on the work boat 3 while towing the discharge pipe 4 and inclining it toward the rear in the ship traveling direction.
The liquid carbon dioxide stored in the tank is discharged through the discharge pipe 4 into the sea. In this case, when liquid carbon dioxide is sent from the upper end of the discharge pipe 4 into the inside thereof, the liquid carbon dioxide is discharged from the discharge pipe 4
And flows down to reach the lower end of the discharge pipe 4.
As shown by the arrow in FIG. 2, the liquid carbon dioxide that has reached the lower end of the discharge pipe 4 flows downward from the lower end opening 11 of the discharge pipe 4 into the storage chamber 13 surrounded by the outer cylinder 12, and
The outer cylinder 12 while spreading radially against the lower end wall 12b of the outer cylinder 12
Flows toward the outer peripheral side of the outer cylinder 12 along the lower end wall 12b of the outer cylinder 12, and further turns upward by contacting the peripheral wall portion 12c of the outer cylinder 12, flows upward along the peripheral wall portion 12c, and To the upper end wall 12a. In the course of such a flow, the liquid carbon dioxide is discharged from the discharge holes 14 located on the lower side in each of the discharge hole rows formed vertically on the peripheral wall portion 12c of the outer cylinder 12.
From the water to the discharge hole 14 located on the upper side, and are sequentially discharged into the sea. That is, first, the lower end opening 1 of the discharge pipe 4
The liquid carbon dioxide flowing downward from 1 and flowing toward the outer peripheral side of the outer cylinder 12 along the lower end wall 12b of the outer cylinder 12 is:
A part is discharged into the sea from the discharge hole 5 located at the bottom. Next, the liquid carbon dioxide rises along the outer peripheral wall 12c of the cylinder 12 and a part of the discharge hole 1 is located second from the bottom.
4 to be released into the sea. In this way, the liquid carbon dioxide flows from the lower end to the upper end of the storage chamber 13,
The liquid carbon dioxide is sequentially discharged into the sea from the discharge hole 5 located on the lower side to the discharge hole 5 located on the upper side, and the remaining liquid carbon dioxide is finally discharged into the sea from the discharge hole 5 located on the uppermost side. Here, the liquid carbon dioxide is discharged at the maximum pressure from the discharge hole 14 located at the lowermost side. And
Thereafter, the liquid carbon dioxide is sequentially discharged from each of the discharge holes 14 arranged from the lower side to the upper side while rising, and into the sea, a pressure loss is sequentially generated each time the liquid carbon dioxide is discharged at each of the discharge holes 5, and accordingly, The pressure at which the liquid carbon dioxide is discharged from each discharge hole 5 gradually decreases. Further, as the depth in the sea corresponding to the discharge hole 14 located at the bottom is the deepest, and thereafter the position of the discharge hole 14 shifts from the lower side to the upper side, the discharge hole 14 The corresponding underwater depth gradually decreases and becomes shallower. As a result, the pressure applied to the liquid carbon dioxide discharged from the discharge hole 14 located at the lowermost position is the highest, and the depth gradually decreases as the position of the discharge hole 5 moves from the lower side to the upper side. Accordingly, the pressure applied to the liquid carbon dioxide discharged from each discharge hole 14 gradually decreases. For this reason, liquid carbon dioxide is discharged into the sea at the highest pressure from the discharge hole 14 located at the lowest side where the highest pressure is applied. That is, the liquid carbon dioxide is discharged into the sea at a large pressure in an appropriate range corresponding to the pressure applied to the liquid carbon dioxide according to the position of the lowermost discharge hole 14. As a result, the liquid carbon dioxide discharged from the lowermost discharge hole 14 generates droplets in an appropriate state. Next, liquid carbon dioxide is discharged from the discharge hole 14 located at the second position from the bottom where a pressure lower than the discharge hole 14 located at the lowermost position acts, at a pressure smaller than the discharge hole 14 at the lowermost position. Generate droplets. As the pressure applied to the liquid carbon dioxide decreases as the position of the discharge hole 5 moves from the lower side to the upper side in this way, the pressure discharged to each discharge hole 14 is sequentially reduced, and the liquid carbon dioxide is reduced. Is released into the sea to form droplets. Then, liquid carbon dioxide is discharged at the lowest pressure from the uppermost discharge hole 14 to which the lowest pressure is applied to generate droplets. The liquid carbon dioxide flowing into the outer cylinder 12 from the lower end opening 11 of the discharge pipe 4 in this manner is
Pressure loss due to discharge from each discharge hole 14 formed in
It flows in a direction that balances pressure changes due to water depth. Therefore, depending on the position of each discharge hole 14, the liquid carbon dioxide is discharged at a pressure in an appropriate range corresponding to the pressure applied to the liquid carbon dioxide discharged from the discharge hole 14, and each discharge hole 14 is discharged. Droplets can be generated with the liquid carbon dioxide discharged each time. Therefore, appropriate and uniform droplets can be generated for each discharge hole 14. The present invention is not limited to the above-described embodiment, but can be implemented with various modifications. As described above, according to the carbon dioxide discharge device of the present invention, the liquid carbon dioxide flowing out from the lower end opening of the discharge pipe into the outer cylinder is supplied to each discharge hole formed in the outer cylinder. It flows in a direction that balances the pressure loss due to the discharge from the water and the pressure change due to water depth. Therefore, the present invention discharges liquid carbon dioxide at an appropriate range of pressure corresponding to the pressure applied to the liquid carbon dioxide discharged from the discharge hole according to the position of each discharge hole, and for each discharge pipe Droplets can be appropriately and uniformly generated with the liquid carbon dioxide discharged respectively.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a carbon dioxide discharge device according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a discharge portion of a discharge pipe provided in the discharge device according to the embodiment. FIG. 3 is a diagram schematically showing a system for discharging carbon dioxide. FIG. 4 is a diagram schematically showing an apparatus for discharging carbon dioxide. FIG. 5 is a diagram schematically showing a state of liquid carbon dioxide discharged into the sea by the discharge device. FIG. 6 is a diagram showing a phase state of carbon dioxide. [Description of Signs] 3 ... Work boat, 4 ... Discharge pipe, 11 ... Lower end opening, 12 ... Outer cylinder, 13 ... Accommodation chamber, 14 ... Discharge hole.

Claims (1)

Claims: 1. A discharge device for sending liquid carbon dioxide into a discharge pipe suspended from the ship sailing in the sea into the sea and discharging the liquid carbon dioxide from the discharge pipe into the sea, wherein a lower end of the discharge pipe is provided. An opening through which the liquid carbon dioxide flowing inside the discharge pipe flows out is formed, and the lower end of the discharge pipe surrounds the outer periphery thereof and accommodates the liquid carbon dioxide flowing out from the lower end opening of the discharge pipe. An outer cylinder is provided that forms a storage chamber that flows in a direction opposite to the direction in which the liquid carbon dioxide flows out of the lower end opening, and a plurality of discharge holes for discharging the liquid carbon dioxide stored in the storage chamber into the sea are provided on the peripheral wall of the outer cylinder. A carbon dioxide discharge device, which is formed side by side in a direction.