JP3552920B2

JP3552920B2 - Carbon dioxide discharge device

Info

Publication number: JP3552920B2
Application number: JP23152898A
Authority: JP
Inventors: 雅彦尾崎; 宗二溝上
Original assignee: Research Institute of Innovative Technology for Earth
Current assignee: Research Institute of Innovative Technology for Earth
Priority date: 1998-08-18
Filing date: 1998-08-18
Publication date: 2004-08-11
Anticipated expiration: 2018-08-18
Also published as: JP2000061297A

Description

【０００１】
【発明の属する技術分野】
本発明は回収した二酸化炭素を海中に放流して海水に溶し込む二酸化炭素の放流装置に関する。
【０００２】
【従来の技術】
近時、地球温暖化が大きな問題となっており、これに伴い地球規模での気候変動を引き起こす可能性があると指摘される温室効果をもった二酸化炭素（ＣＯ_２）の大気中における濃度の上昇を抑えることが特に重要となってきている。そして、この対策のひとつとして火力発電所などで排出される燃焼排ガス中の二酸化炭素を回収して海洋へ送り込むことによって、長期に亘って二酸化炭素を大気から隔離する構想が提案されているが、その成立にあたっては二酸化炭素を送り込む海洋において新たな環境影響が引き起こされないようにすることが必要となっている。
【０００３】
二酸化炭素送り込みによる海洋環境への影響を小さくするシステムとして、次に述べる２種類のシステムが提案されている。その一つは貯蓄型と称されるもので、二酸化炭素を深海底のくぼみのような場所に集中して溜めることにより影響範囲を特定の場所に限定して局所化しようとする方法である。
【０００４】
もう一つのシステムは、溶解拡散型と称されるもので、二酸化炭素を海水中に溶し込んで薄く希釈し広く拡散させて海水中の二酸化炭素の濃度の上昇を抑制しようとする方法であり、本来海水中に溶解している二酸化炭素の濃度がある程度上昇するにとどまるという考え方に基くものである。
【０００５】
この溶解拡散型における具体的な方法として、船舶により二酸化炭素の放流点を移動させて海中の中層にて二酸化炭素を放流する中層希釈放流方式が挙げられている。この方式について図３ないし図５を参照して説明する。図３は中層希釈放流方式放流のシステムを模式的に示す説明図、図４（ａ）は同方式において放流管から二酸化炭素を海中へ放流拡散する状態を模式的に示す説明図、図４（ｂ）は図４（ａ）のＺ部を拡大して示す図、図５は二酸化炭素を放流管から放流して形成された液滴の状態を示す説明図である。
【０００６】
この中層希釈放流方式は、陸上プラント１で燃焼排ガスから分離、回収した二酸化炭素を液化し、その液化ガスを貯溜タンク２ａに充填して液化ガス運搬船２にて所定の海域まで海上輸送し、そこで貯溜タンク２ａの内部の液体二酸化炭素を作業船３に搭載した貯溜タンク３ａに移し替える。液体二酸化炭素は例えば圧力が６ａｔｍ、温度が−５５℃とする。図６は二酸化炭素の相状態を示す線図であるが、この線図で判るように前記６ａｔｍ、温度を−５５℃は液体二酸化炭素を経済的に得ることができる条件である。作業船３は深さ２０００ｍないし２５００ｍの海中に吊り下げる大変長い鋼管などからなる放流管４を備え、この放流管４は下端面が閉塞されるとともに下端部の周壁には複数の放流孔５が上下方向に間隔を存して一列に並べて形成されている。そして、液体二酸化炭素を貯溜タンク３ａから放流管４に送り込んで放流管４の下端部に上下方向に並んで形成した複数個の放流孔５から海中に放流する。作業船３は放流管４の孔５から液体二酸化炭素を海中に放流しつつ前進することにより、液体二酸化炭素の放流点を局所に限定せず移動させて液体二酸化炭素の希釈を増進させている。なお、運搬船２と作業船３とは別なものであっても、また両者が兼用するものであっても良い。ＳＬは海面である。
【０００７】
放流管４から放流された液来二酸化炭素の状態は、現状の知見から次のように想定される。放流管４の孔５から海中へ放流された液体二酸化炭素６はすぐに海水に溶け込んでしまわないで、放流管４が後流に生成して残して行く渦８による変動流場９の中で多数の液滴７となって分散してほぼ均一に海水と混合される。放流管４は対向する海流に対する相対的な流速によって船舶進行方向に向かって後側へ傾斜し、その背後に管軸線とほぼ平行な回転軸４をもつ後流渦を連続的に生成しながら進んでいく。渦８のパターンは放流管の形状、表面の状態および寸法や移動速度などの条件によって異なるが、外径数１０ｃｍの管が数ノットの速度で進む場合には、通常進行方向に向かって管左右両側から入れ替わり渦が発生して変動流場９を後に残していき、その中で液体二酸化炭素と海水とが混合すると考えられる。
【０００８】
そして、二酸化炭素の液滴７は放流管４の後流からさらに周辺の海水に溶け込みながら緩やかに海水中を上昇していく。すなわち、液体二酸化炭素の液滴７は海水中を上昇しながら海水に溶け込んでいくことによって直径が小さくなっていく。そして、液滴７がある高さまで上昇する過程で液体二酸化炭素は全て海水中に溶け込んでしまい液滴７が消滅する。
【０００９】
中層希釈放流方式は、海面から約２０００ｍないし２５００ｍの深さ（中層）の海中で液体二酸化炭素の放流を行うものである。すなわち、２０００ｍより上層の海中で液体二酸化炭素の放流を行うと、放流された液体二酸化炭素が全て海水に溶け込まない内に液滴が海面に達する可能性があり、約２０００ｍないし２５００ｍの深さの海中で液体二酸化炭素の放流を行なうと液滴が海面に達する前に全ての二酸化炭素を海水に溶け込ませることができる。
【００１０】
【発明が解決しようとする課題】
このように中層希釈放流方式を採用した放流装置は、二酸化炭素を海洋へ放流して隔離する上で大変有望な装置と考えられているが、この放流装置には次に述べる問題がある。
【００１１】
放流管４の内部を流れ降りてきた液体二酸化炭素は放流管の下端部に上下方向に並んで形成された複数の放流孔５の夫々から海中へ放流される、すなわち、放流管４の内部を流れ降りてきた液体二酸化炭素はまず一部が一番上に位置する放流孔５から放流され、次いで残りの一部が上から２番目に位置する放流孔５から放流される。このようにして液体二酸化炭素は上に位置する放流孔５から下に位置する放流孔５にかけて順次放流されてゆき、最後に残った液体二酸化炭素が一番下の放流孔５から放流される。
【００１２】
このように液体二酸化炭素は上から下にかけて並ぶ各放流孔５から順次海中へ放流されていく過程で、各放流孔５から放流されるに毎に圧力損失が発生する。すなわち、液体二酸化炭素は上から下にかけて並ぶ各放流孔５にかけて順次放流されてゆくに従い放流される圧力が低下してゆく。
【００１３】
ところで、上下方向に並ぶ放流孔５の位置が下側へ移るに従い各放流孔５に対応する海中の深度が順次増大してゆき（深くなる）、この深度の増大に伴い複数の放流孔５の位置が上側から下側へゆくに従い各放流孔５毎に放流する液体二酸化炭素に加わる圧力が順次増大してゆく。各放流孔５毎に夫々放流した液体二酸化炭素が海中に液滴を生成させるためには、各放流孔５の位置に応じてその放流孔５から放流される液体二酸化炭素に加わる圧力に対応した適切な大きさの範囲の圧力で液体二酸化炭素を放流する必要がある。このため、放流孔５の位置が上側から下側に移るに従い放流する液体二酸化炭素に加わる圧力の増大に応じて、各放流孔５毎に液体二酸化炭素を放流する圧力を順次増大してゆく必要がある。
【００１４】
ところが、前述したように実際には液体二酸化炭素は各放流孔５からの放流に伴う圧力損失と水深による圧力変化とが均衡しない向きに流れ、放流孔５が下側に位置するに従い液体二酸化炭素の放流圧力が低下してゆくために、各放流孔５毎にその位置に応じた適切な大きさの範囲は液体二酸化炭素の放流圧力が得られずに、各放流孔５から海中に放流された液体二酸化炭素により液滴が適切且つ均一に形成されないことがある。例えば、上側に位置する放流孔から液体二酸化炭素を放流すると圧力が高すぎて液滴がスプレー状になり、また下側に位置する放流孔では圧力が低すぎて液体二酸化炭素が放流されず液滴が生成されないことがある。
【００１５】
本発明は前記事情に基いてなされたもので、放流管に設けた複数の放流孔からその位置に応じた適切な圧力で液体二酸化炭素を放流して液滴を形成できる二酸化炭素の放流装置を提供することを課題とする。
【００１６】
【課題を解決するための手段】
本発明の二酸化炭素の放流装置は、海上を航走する船から海中に吊り下げた放流管の内部に液体二酸化炭素を送り込んで放流管から海中へ放流する放流装置において、
前記放流管の下端に前記放流管内部を流れてきた液体二酸化炭素が流出する開口を形成し、且つ前記放流管の下端部にその外側周囲を囲んで前記放流管の下端開口から流出した液体二酸化炭素を収容して前記下端開口から流出する向きとは逆向きに流す収容室を形成する外筒を設け、この外筒の周壁に前記収容室に収容された液体二酸化炭素を海中へ放流する複数の放流孔を上下方向に並べて形成したことを特徴とする。
【００１７】
【発明の実施の形態】
本発明の実施の形態について図１および図２を参照して説明する。
【００１８】
図１はこの実施の形態にかかわる放流装置を模式的に示す図、図２はこの放流装置における放流管の液体二酸化炭素放流部を模式的に示す拡大断面図である。本発明は、前述した図３ないし図５にて示す液体二酸化炭素を中層希釈放流方式により海洋へ放流する装置を対象としており、図１において図３と同じ部分は同じ符号を付して示している。図中３は作業船、３ａは作業船３に搭載された液体二酸化炭素を貯溜するタンク、４は作業船３に取付けられて海中に吊り下げられタンク３ａに貯溜された液体二酸化炭素を上端から送り込んで流して海中へ放出する放流管である。
【００１９】
本発明では放流管４の下端部に液体二酸化炭素を放出するために次に述べる構成が採用している。放流管４は断面円形をなすとともに、作業船３から深さ２０００ｍないし２５００ｍの海中に吊り下げられて作業船３の航走により曳航されることが可能な長さを有している。この放流管４の下端部の周壁には放流孔が形成されておらず、下端部には放流管４内部を流れてきた液体二酸化炭素が流出する開口１１が形成されている。放流管４の下端部にはその外側周囲を囲む外筒１２が設けられている。この外筒１２は両端を閉塞した円筒体をなすもので、その長さおよび直径は放流孔４を囲んで所定量の大きさの収容室１３を形成し、且つ所定の数の放流孔１４を上下方向に並べて形成することが可能な大きさに設定する。例えば外筒１２の直径は１ｍ前後、長さは数１０ｍである。
【００２０】
外筒１２は放流管４の下端部を囲むように放流管４と同一中心軸線上に配置され、放流管４に対して適宜な手段により固定されている。放流管４は外筒１２の上端壁１２ａの中心を貫通して外筒１２の内部に挿入され、その下端開口１１は外筒１２の下端壁１２ｂから離間した位置にあり液体二酸化炭素を放流管４の下端壁１２ａに向けて流出させるようにしてある。
【００２１】
このようにして設けた外筒１２の内部の空間には放流管４の下端部の周囲に同心円をなす収容室１３が形成され、この収容室１３で放流管４の下端開口１１から流出された液体二酸化炭素を収容して下端開口１１から流出する向き（下向き）とは逆向き（上向き）に流すように形成されている。この外筒１２の周壁部１２ｃには、円周方向の複数箇所に夫々複数個の放流孔１４を上下方向に間隔を存して一列，千鳥状、その他の形態に並べて形成する。この放流孔１４の大きさ、数は液体二酸化炭素の放流量などの条件を考慮して設定する。例えば、外筒１２の上端壁部１２ａの付近から下端壁部１２ｂの付近まで上下方向に放流孔１４を形成する。
【００２２】
このように構成した放流装置は、作業船３を航走させて放流管４を曳航して船進行方向後側へ向けて傾斜させながら、作業船３に搭載した貯溜タンク３ａに貯溜された液体二酸化炭素を放流管４を通して海中に放流する。この場合、液体二酸化炭素を放流管４の上端からその内部へ送り込むと、液体二酸化炭素は放流管４の内部を下降して流れて放流管４の下端部に到達する。図２の矢印で示すように放流管４の下端部に到達した液体二酸化炭素は放流管４の下端開口１１から外筒１２で囲まれた収容室１３の内部に下向きに流出し、外筒１２の下端壁１２ｂに当って放射状に広がりながら外筒１２の下端壁１２ｂに沿って外筒１２の外周側へ向けて流れ、さらに外筒１２の周壁部１２ｃに当って上向きに向きを変え、周壁部１２ｃに沿って上側に向けて流れて外筒１２の上端壁１２ａに達する。
【００２３】
このように流れる過程で液体二酸化炭素は、外筒１２の周壁部１２ｃに上下方向に沿って並べて形成した各放流孔列のなかで下側に位置する放流孔１４から上側に位置する放流孔１４へと位置を移して順次海中へ放流される。すなわち、まず放流管４の下端開口１１から下向きに流出して外筒１２の下端壁１２ｂに沿って外筒１２の外周側へ向けて流れた液体二酸化炭素は、一部が一番下に位置する放流孔５から海中へ放流される。次いで、液体二酸化炭素は筒１２の外周壁１２ｃに沿って上昇して一部が下から２番目に位置する放流孔１４から海中へ放流される。このようにして液体二酸化炭素は収容室１３の下端から上端へ向けて流れる過程で、下側に位置する放流孔５から上側に位置する放流孔５にかけて順次海中へ放流されてゆき、最後に残った液体二酸化炭素は一番上側に位置する放流孔５から海中へ放流される。
【００２４】
ここで、液体二酸化炭素は一番下側に位置する放流孔１４から最大の圧力で放流される。そして、それ以降液体二酸化炭素は、上昇しながら下側から上側にかけて並ぶ各放流孔１４から順次海中へ放流されていく過程で各放流孔５で放流される毎に順次圧力損失が生じて、これに伴い各放流孔５毎に液体二酸化炭素を放流する圧力が順次低下してゆく。また、一番下側に位置する放流孔１４に対応する海中の深度が一番深く、それ以降放流孔１４が下側から上側へ位置を移すに従い、各放流孔１４毎にその放流孔１４に対応する海中の深度が順次減少して浅くなってゆく。これにより一番下側に位置する放流孔１４から放流する液体二酸化炭素に加わる圧力が一番大きく、放流孔５が下側から上側へ位置を移すのに伴って深度が順次減少してゆくのに従い、各放流孔１４毎に放流する液体二酸化炭素に加わる圧力が順次減少してゆく。
【００２５】
このため、一番大きな圧力が加わる一番下側に位置する放流孔１４から一番大きな圧力で液体二酸化炭素を海中へ放流する。すなわち、一番下側の放流孔１４の位置に応じて液体二酸化炭素に加わる圧力に対応した適切な範囲の大きな圧力で液体二酸化炭素を海中に放流する。これにより一番下側の放流孔１４から放出された液体二酸化炭素は適切な状態で液滴を生成する。次いで、一番下側に位置する放流孔１４より低い圧力が作用する下から２番目に位置する放流孔１４からは、一番下側の放流孔１４より小さい圧力で液体二酸化炭素を放流して液滴を生成させる。このように放流孔５が下側から上側へ位置を移すのに伴って液体二酸化炭素に加わる圧力が減少してゆくのに従って、各放流孔１４毎に放流する圧力を順次減少して液体二酸化炭素を海中に放流して液滴を生成してゆく。そして、一番小さな圧力が加わる一番上側に位置する放流孔１４から一番小さな圧力で液体二酸化炭素を放流して液滴を生成する。
【００２６】
このようにして放流管４の下端開口１１から外筒１２内部へ流出した液体二酸化炭素は、外筒１２に形成した各放流孔１４からの放流に伴う圧力損失と、水深による圧力変化とを均衡させる向きに流れる。従って、各放流孔１４の位置に応じて、その放流孔１４から放流される液体二酸化炭素に加わる圧力に対応した適切な範囲の大きさの圧力で液体二酸化炭素を放流して、各放流孔１４毎に夫々放流した液体二酸化炭素で液滴を生成させることができる。このため、各各放流孔１４毎に夫々適切で均一な液滴を生成することができる。
【００２７】
なお、本発明は前述した実施の形態に限定されずに、種々変形して実施することができる。
【００２８】
【発明の効果】
以上説明したように本発明の二酸化炭素の放流装置によれば、放流管の下端開口から外筒内部へ流出した液体二酸化炭素が、外筒に形成した各放流孔からの放流に伴う圧力損失と水深による圧力変化とを均衡させる向きに流れる。従って、本発明は、各放流孔の位置に応じてその放流孔から放流される液体二酸化炭素に加わる圧力に対応した、適切な範囲の圧力で液体二酸化炭素を放流して、各放流管毎に夫々放流した液体二酸化炭素で液滴を適切且つ均一に生成させることができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態にかかわる二酸化炭素の放流装置を模式的に示す図。
【図２】同実施の形態における放流装置に設ける放流管の放流部を拡大して示す断面図。
【図３】二酸化二酸化炭素の放流システムを模式的に示す図。
【図４】二酸化二酸化炭素の放流装置を模式的に示す図。
【図５】放流装置により海中に放流された液体二酸化炭素の状態を模式的に示す図。
【図６】二酸化炭素の相状態を示す線図。
【符号の説明】
３…作業船、
４…放流管、
１１…下端開口、
１２…外筒、
１３…収容室、
１４…放流孔。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for discharging carbon dioxide that discharges recovered carbon dioxide into the sea and dissolves it in seawater.
[0002]
[Prior art]
In recent years, global warming has become a major problem, and it has been pointed out that the concentration of carbon dioxide (CO ₂ ) in the atmosphere with a greenhouse effect, which has been pointed out as a possibility of causing climate change on a global scale, is increasing. It is particularly important to control the rise. As one of the measures, a concept has been proposed in which carbon dioxide in combustion exhaust gas discharged from thermal power plants and the like is collected and sent to the ocean, thereby isolating carbon dioxide from the atmosphere for a long time. In order to achieve this, it is necessary to ensure that no new environmental impacts are caused in the ocean that sends carbon dioxide.
[0003]
The following two types of systems have been proposed as systems for reducing the influence on the marine environment due to the feeding of carbon dioxide. One of them is a storage type, which is a method in which the area of influence is limited to a specific place and localized by storing carbon dioxide intensively in a place such as a hollow on the deep sea floor.
[0004]
Another system, called the dissolution-diffusion type, is a method in which carbon dioxide is dissolved in seawater, diluted dilutely and diffused widely to suppress the rise in the concentration of carbon dioxide in seawater. However, it 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 of the dissolution-diffusion type, there is a middle-layer dilution discharge method 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 the middle-layer dilution discharge method, and FIG. 4A is an explanatory view schematically showing a state in which carbon dioxide is discharged and diffused from the discharge pipe into the sea in the same method, and FIG. 4B is an enlarged view of a portion Z in FIG. 4A, and FIG. 5 is an explanatory view showing a state of droplets formed by discharging carbon dioxide from a discharge pipe.
[0006]
This middle-layer dilution discharge method liquefies the carbon dioxide separated and recovered from the flue gas in the land plant 1, fills the liquefied gas into the storage tank 2a, and transports the liquefied gas to the predetermined sea area by the liquefied gas carrier 2 where it is transported by sea. The liquid carbon dioxide inside 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. The work boat 3 is provided with a discharge pipe 4 made of a very long steel pipe or the like suspended from the sea at a depth of 2000 m to 2500 m. The discharge pipe 4 has a lower end face closed and a plurality of discharge holes 5 formed in a peripheral wall at the lower end. They are arranged in a line at intervals in the vertical direction. Then, the liquid carbon dioxide is sent 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.
[0007]
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. A large number of 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 by the relative flow velocity with respect 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. However, when a pipe having an outer diameter of several 10 cm advances at a speed of several knots, the pipe normally moves left and right in the direction of travel. It is considered that the swirl is generated from both sides and the fluctuating flow field 9 is left behind, in which the liquid carbon dioxide and the seawater mix.
[0008]
Then, the carbon dioxide droplet 7 gradually rises in the seawater from the wake of the discharge pipe 4 while being dissolved in the surrounding seawater. 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, during the process in which the droplet 7 rises to a certain height, all the liquid carbon dioxide is dissolved in the seawater, and the droplet 7 disappears.
[0009]
The middle-layer dilution discharge method discharges liquid carbon dioxide in the sea at a depth of about 2000 m to 2500 m (middle layer) from the sea surface. That is, when liquid carbon dioxide is discharged in the sea above 2000m, the liquid droplets may reach the sea surface before all the discharged liquid carbon dioxide does not dissolve in the seawater, and a depth of about 2000m to 2500m The release of liquid carbon dioxide in the sea allows all of the carbon dioxide to dissolve into the seawater before the droplets reach the sea surface.
[0010]
[Problems to be solved by the invention]
The discharge device employing the middle-level dilution discharge method is considered to be a very promising device for discharging and isolating carbon dioxide into the ocean, but this discharge device has the following problems.
[0011]
The liquid carbon dioxide that has flowed down the inside of the discharge pipe 4 is discharged into the sea from each of a plurality of discharge holes 5 formed in the lower end portion of the discharge pipe and arranged vertically, that is, through the inside of the discharge pipe 4. Part of the liquid carbon dioxide that has flowed down 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.
[0012]
As described above, in the process in which the liquid carbon dioxide is sequentially discharged into the sea from the discharge holes 5 arranged from the top to the bottom, a pressure loss is generated each time the liquid carbon dioxide is discharged from the discharge holes 5. That is, as the liquid carbon dioxide is successively discharged to the respective discharge holes 5 arranged from top to bottom, the pressure to be discharged decreases.
[0013]
By the way, as the position of the discharge holes 5 arranged in the vertical direction moves downward, the depth in the sea corresponding to each discharge hole 5 gradually increases (increases), and as the depth increases, a plurality of discharge holes 5 As the position 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 a droplet in the sea, 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 must 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 according to the increase in the pressure applied to the liquid carbon dioxide discharged. There is.
[0014]
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. The discharge pressure of the liquid carbon dioxide is reduced, so that a range of an appropriate size corresponding to the position of each discharge hole 5 is discharged from each discharge hole 5 into the sea without obtaining the discharge pressure of the liquid carbon dioxide. Droplets may not be formed properly and uniformly due to liquid carbon dioxide. 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 the pressure is too low in the discharge hole located on the lower side so that liquid carbon dioxide is not discharged and the liquid is discharged. Drops may not be formed.
[0015]
The present invention has been made based on the above circumstances, and a carbon dioxide discharge device 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 according to the position thereof. The task is to provide.
[0016]
[Means for Solving the Problems]
The carbon dioxide discharge device of the present invention is a discharge device that sends liquid carbon dioxide into a discharge pipe suspended in the sea from a ship traveling on the sea and discharges the discharge from the discharge pipe into the sea,
An opening through which the liquid carbon dioxide flowing inside the discharge pipe flows out is formed at the lower end of the discharge pipe, and the liquid dioxide flowing out from the lower end opening of the discharge pipe surrounding the outer periphery at the lower end of the discharge pipe. An outer cylinder that forms a storage chamber that stores carbon and flows in a direction opposite to the direction in which the carbon flows out of the lower end opening; and a plurality of discharge pipes for discharging the liquid carbon dioxide stored in the storage chamber to the sea on the peripheral wall of the outer cylinder. Are formed in such a manner that the discharge holes are vertically arranged.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0018]
FIG. 1 is a view schematically showing 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 the 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, reference numeral 3 denotes a work boat, 3a denotes a tank for storing liquid carbon dioxide mounted on the work boat 3, and 4 denotes a liquid carbon dioxide attached to the work boat 3 and suspended under the sea and stored in the tank 3a. It is a discharge pipe that sends in, discharges, and discharges into the sea.
[0019]
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.
[0020]
The outer cylinder 12 is arranged 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. The discharge pipe 4 penetrates through the center of the upper end wall 12 a of the outer cylinder 12 and is inserted into the outer cylinder 12. The lower end opening 11 is located at a position separated from the lower end wall 12 b of the outer cylinder 12 and discharges liquid carbon dioxide. 4 to the lower end wall 12a.
[0021]
A concentric storage chamber 13 is formed around the lower end of the discharge pipe 4 in the space inside the outer cylinder 12 thus provided, and the storage chamber 13 flows out of the lower end opening 11 of the discharge pipe 4. It is formed so as to accommodate the liquid carbon dioxide and flow it in the direction (upward) opposite to the direction (downward) flowing out from the lower end opening 11. On the peripheral wall portion 12c of the outer cylinder 12, a plurality of discharge holes 14 are formed at a plurality of positions in the circumferential direction, and are arranged in a line, in a staggered shape, 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 flow rate of liquid carbon dioxide. For example, the discharge hole 14 is formed vertically from near the upper end wall 12a of the outer cylinder 12 to near the lower end wall 12b.
[0022]
The discharge device configured as described above is configured such that the liquid stored in the storage tank 3a mounted on the work boat 3 is moved while the work boat 3 is running, the discharge pipe 4 is towed, and the discharge pipe 4 is tilted rearward in the ship traveling direction. Carbon dioxide is discharged into the sea through the discharge pipe 4. In this case, when liquid carbon dioxide is sent from the upper end of the discharge pipe 4 to the inside thereof, the liquid carbon dioxide descends inside the discharge pipe 4 and flows 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 accommodation chamber 13 surrounded by the outer cylinder 12, and While flowing radially toward the lower end wall 12b of the outer cylinder 12 and flowing toward the outer peripheral side of the outer cylinder 12 along the lower end wall 12b of the outer cylinder 12, the outer wall 12 further turns upward by hitting the peripheral wall portion 12c of the outer cylinder 12, It flows upward along the portion 12c and reaches the upper end wall 12a of the outer cylinder 12.
[0023]
In the course of such a flow, the liquid carbon dioxide flows from the discharge hole 14 located on the lower side to the discharge hole 14 located on the upper side in each of the discharge hole arrays formed in the peripheral wall portion 12c of the outer cylinder 12 along the vertical direction. It is released to the sea sequentially after shifting its position. That is, first, the liquid carbon dioxide flowing downward from the lower end opening 11 of the discharge pipe 4 and flowing toward the outer peripheral side of the outer cylinder 12 along the lower end wall 12b of the outer cylinder 12 is partially located at the bottom. The water is discharged into the sea from the discharge hole 5. Next, the liquid carbon dioxide rises along the outer peripheral wall 12c of the cylinder 12 and a part thereof is discharged into the sea from the discharge hole 14 located second from the bottom. In the process of flowing the liquid carbon dioxide from the lower end to the upper end of the storage chamber 13 in this manner, 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 finally remains. The discharged liquid carbon dioxide is discharged into the sea from the discharge hole 5 located at the uppermost position.
[0024]
Here, the liquid carbon dioxide is discharged at the maximum pressure from the discharge hole 14 located at the lowermost side. Then, in the process where the liquid carbon dioxide is subsequently discharged from each discharge hole 14 lined up from the lower side to the upper side while rising, into the sea, a pressure loss is sequentially generated each time the liquid carbon dioxide is discharged at each discharge hole 5. As a result, the pressure at which 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 moves from the lower side to the upper side, each 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 greatest, 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.
[0025]
Therefore, the 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 within an appropriate range corresponding to the pressure applied to the liquid carbon dioxide according to the position of the lowermost discharge hole 14. Thereby, 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 second discharge hole 14 from the lower side where the 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, 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, the liquid carbon dioxide is discharged at the lowest pressure from the discharge hole 14 located at the uppermost side where the lowest pressure is applied, thereby generating droplets.
[0026]
The liquid carbon dioxide that has flowed out of the lower end opening 11 of the discharge pipe 4 into the outer cylinder 12 in this way balances the pressure loss due to the discharge from each discharge hole 14 formed in the outer cylinder 12 and the pressure change due to the water depth. It flows in the direction to make it. Therefore, depending on the position of each discharge hole 14, the liquid carbon dioxide is discharged at a pressure within 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.
[0027]
The present invention is not limited to the above-described embodiment, but can be implemented with various modifications.
[0028]
【The invention's effect】
As described above, according to the carbon dioxide discharge device of the present invention, the liquid carbon dioxide that has flowed into the outer cylinder from the lower end opening of the discharge pipe has a pressure loss due to discharge from each discharge hole formed in the outer cylinder. It flows in a direction that balances pressure changes 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 by the liquid carbon dioxide discharged respectively.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a carbon dioxide discharging device according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing a discharge section of a discharge pipe provided in the discharge device according to the embodiment.
FIG. 3 is a diagram schematically showing a discharge system of 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.
[Explanation of symbols]
3. Work boat,
4 ... discharge pipe,
11 ... lower end opening,
12 ... outer cylinder,
13 ... accommodation room,
14 ... discharge hole.

Claims

In a discharge device that sends liquid carbon dioxide into the discharge pipe suspended in the sea from a ship traveling on the sea and discharges it from the discharge pipe to the sea,
An opening through which the liquid carbon dioxide flowing through the inside of the discharge pipe flows out is formed at the lower end of the discharge pipe, and the liquid dioxide flowing out of the lower end opening of the discharge pipe surrounding the outer periphery at the lower end of the discharge pipe. An outer cylinder is provided that forms a storage chamber that stores carbon and flows in a direction opposite to the direction in which the carbon flows out from the lower end opening. A discharge device for carbon dioxide, wherein discharge holes of the carbon dioxide are arranged vertically.