JP4832649B2

JP4832649B2 - Method and apparatus for receiving liquid such as LNG

Info

Publication number: JP4832649B2
Application number: JP2001002552A
Authority: JP
Inventors: 貴之渡邉; 誠尾崎
Original assignee: IHI Plant Construction Co Ltd
Current assignee: IHI Plant Construction Co Ltd
Priority date: 2001-01-10
Filing date: 2001-01-10
Publication date: 2011-12-07
Anticipated expiration: 2021-01-10
Also published as: JP2002206694A

Description

【０００１】
【発明の属する技術分野】
本発明は、ＬＮＧサテライト基地におけるＬＮＧ、液化エチレン貯蔵設備における液化エチレン、その他、常温における飽和圧力が大気圧力より高い液を、輸送車或いは他のタンクから貯蔵タンク等へ受け入れるためのＬＮＧ等の受入液の受入方法及びその装置に係り、特にその受入液を受け入れる際に、タンク内の昇圧を抑制できるＬＮＧ等の受入液の受入方法及びその装置に関するものである
【０００２】
【従来の技術】
従来のＬＮＧサテライト基地等におけるＬＮＧの受入を図３により説明する。
【０００３】
図３において、１０Ａ，１０Ｂは、ＬＮＧ、液化エチレン、その他、常温における飽和圧力が大気圧力より高い貯蔵液１１を貯蔵する貯蔵タンクで、敷地の問題から縦型の二重円筒状に形成される。
【０００４】
この貯蔵タンク１０Ａ，１０Ｂに貯蔵される貯蔵液１１は、加圧気化器１９からのガスにより運転圧力に維持されている。気相部１２Ａ，１２Ｂは、ガスライン（又はベントライン）１４に接続した圧力調整弁１３Ａ，１３Ｂにて、入熱等により運転圧力が上昇する場合は、ガスを排出することにより、貯蔵液１１を払い出す運転圧（約０．５５〜６ＭＰａｇ）を保持するようになっている。なお、貯蔵時に入熱で運転圧より高くなったＢＯＧは、適宜圧力調整弁１３Ａ，１３Ｂを介してガスライン（又はベントライン）１４に放出される。
【０００５】
貯蔵タンク１０Ａ，１０Ｂは、図では省略したが複数設けられ、そのうちの例えば１の貯蔵タンク１０Ａの液位が少なく、その貯蔵タンク１０Ａにタンクローリ等の輸送車１５のタンク１６からのＬＮＧを受け入れる場合、タンク１６を加圧して送液するが、輸送車の加圧受入運転では、車両の設計圧力に制約されるために、受入時の貯蔵タンク１０Ａの圧力を、約０．３ＭＰａに落圧して運転される。この落圧は、気相部１２ＡのＢＯＧを適宜の手段で排出して行う。
【０００６】
貯蔵タンク１０Ａを落圧した後、送液運転中の貯蔵タンク１０Ｂの開閉制御弁１７Ｂを開き、払出ライン１８を介して加圧気化器１９に貯蔵液１１を導入して気化し、そのガスをガス弁３２を介してタンク１６に導入してタンク１６内を加圧することで、タンク１６内の液が、受入弁３４から受入ライン２０を介して、貯蔵タンク１０Ａに受け入れる。
【０００７】
このＬＮＧを受け入れる場合、受入ライン２０から貯蔵タンク１０Ａの底部に接続したボトムフィードライン２１よりノズル２２を通して送液すると、充填液により気相部１２Ａのガスが圧縮されて高圧になるため、気相部１２Ａのガスを排出しない限り、受入ができなくなる。通常、ガスライン１４の圧力は、受入時の気相部１２Ａの圧力より高いため、気相部１２Ａの置換ガスをガスライン１４にそのまま放出することはできない。また、受入時のタンク１０Ａの置換ガスをガスライン１４に排出できる場合でも、設備外にＢＯＧを排出することは、タンク１０Ａの残液の濃縮の要因ともなるので好ましい運転方法ではない。
【０００８】
さらに、ＬＮＧの場合、ＢＯＧの主成分はメタンであるため発熱量が小さいので、増熱をしなければならない。受入時の排気量は一時的に多くなるため、熱調設備も対応して通常の設備容量よりも非常に大きくなり、不経済な設備となる。
【０００９】
そこで、トップフィードライン２３より貯蔵タンク１０Ａの頂部から受け入れるようにしている。
【００１０】
この方法により液の充填時に気相部１２Ａのガスが圧縮されて昇圧するのを防止している。すなわち、受入液の飽和圧力（温度）よりも高い圧力（温度）状態にあるガス相に、受入液を受け入れることにより低温の液でガスを吸収液化してガス量を減じて気相部１２Ａの昇圧を防止している。
【００１１】
【発明が解決しようとする課題】
しかしながら、上述したように貯蔵タンク１０Ａ，１０Ｂは、円筒縦型であり、頂部から液を受け入れる場合は、タンクの液面の高さに無関係に頂部までの液頭圧力を加算して、輸送車１５のタンク１６を加圧しなければならないため、受け入れる貯蔵タンク１０Ａ，１０Ｂの液面が低い時には、過剰に加圧していることとなり、タンク１６の耐圧から受入ができないという問題が発生する。
【００１２】
また、気相部１２Ａ，１２Ｂは、運転のため通常温度が高い。また気相部の内槽材料である鋼材からの伝熱は、液相面への輻射伝熱となるため、液温に比較してかなり高くなっている。このような状態の内槽の鋼材に受入液が接触するとＢＯＧが激しく蒸発して圧力が上昇する。この受入初期の気相部１２Ａ，１２Ｂの一時的な昇圧はよく見られる現象である。
【００１３】
このため受け入れ差圧に余裕がないタンク間の移送のような運転では、差圧が不足して運転が続行できなくなることもある。受入回数が少ないタンクの場合は、受入液量に比べてＢＯＧ量が多くなるので、このＢＯＧを有水槽のような他のタンクに一端落圧して、設備外に排出することになり、ＬＮＧのケースではＢＯＧの成分の殆どがメタンからなる軽成分のため、貯蔵液のエタンやブタン等の重成分が相対的に高まり濃縮の原因となるので好ましくない。
【００１４】
なお、貯蔵タンク１０Ａ或いは１０Ｂの貯蔵液１１を利用系に払い出す際には、加圧気化器１９に液を導入して気化させ、ライン２３より圧力調整弁２９Ａ或いは２９Ｂにて貯蔵タンク１０Ａ或いは１０ＢにＢＯＧを供給して運転圧力を維持するようになっている。
【００１５】
そこで、本発明の目的は、上記課題を解決し、貯蔵タンクに低温液を受け入れるに際して、送液するタンクの加圧を高くすることなく、しかも、貯蔵タンクの気相部の圧力も高くすることなく送液できるＬＮＧ等の受入液の受入方法及びその装置を提供することにある。
【００１６】
【課題を解決するための手段】
上記目的を達成するために、請求項１の発明は、ＬＮＧ等の受入液を受け入れる縦型の二重円筒状の貯蔵タンク内を落圧した後、送液運転中の貯蔵タンク内の貯蔵液を払い出して気化させ、これを、輸送車等のＬＮＧ等の受入液を積載したタンクに送ってそのタンクを加圧し、そのタンク内の受入液を上記落圧した貯蔵タンクに受け入れる方法において、受入液を受け入れる貯蔵タンクの液面に、常時受入液が到達するように受入液を貯蔵液中から上向きに液面に向けて噴流として送液し、噴流及び随伴液を液面で気相部のガスと接触させて、置換体積以上にガスを凝縮させるようにしたＬＮＧ等の受入液の受入方法である。
【００１７】
請求項２の発明は、貯蔵タンク内に、噴出高さの異なる複数のノズルを設置し、液面の上昇に応じて、その高さの異なるノズルを切り換えて送液するようにした請求項１記載のＬＮＧ等の受入液の受入方法である。
【００１８】
請求項３の発明は、ＬＮＧ等の受入液を受け入れる縦型の二重円筒状の貯蔵タンク内を落圧した後、送液運転中の貯蔵タンク内の貯蔵液を払い出して気化させ、これを、輸送車等のＬＮＧ等の受入液を積載したタンクに送ってそのタンクを加圧し、そのタンク内の受入液を上記落圧した貯蔵タンクに受け入れる装置において、受入液を受け入れる貯蔵タンクの液面を検出する液位検出手段と、貯蔵タンクの底部から上方に向けてそれぞれ設けられ、受入液を液面に向けて噴流として送液する噴出高さの異なるノズルと、液位検出手段で検出された液面に応じて上記ノズルを切り換えるノズル切換手段とを備え、液位検出手段の検出した液位に応じてノズル切換手段が、上記ノズルから送液する受入液が常時液面に到達するようにノズルを、低位置のノズルから高位置のノズルに順次切り換えて、各ノズルからの噴流及び随伴液を液面で気相部のガスと接触させて、置換体積以上にガスを凝縮させるようにしたＬＮＧ等の受入液の受入装置である。
【００１９】
請求項４の発明は、ＬＮＧ等の受入液を受け入れる縦型の二重円筒状の貯蔵タンク内を落圧した後、送液運転中の貯蔵タンク内の貯蔵液を払い出して気化させ、これを、輸送車等のＬＮＧ等の受入液を積載したタンクに送ってそのタンクを加圧し、そのタンク内の受入液を上記落圧した貯蔵タンクに受け入れる装置において、貯蔵タンクの気相部の圧力を検出する圧力検出手段と、貯蔵タンクの底部から上方に向けてそれぞれ設けられ、受入液を液面に向けて噴流として送液する噴出高さの異なるノズルと、圧力検出手段で検出された圧力が上昇傾向に転じたときに、上記ノズルを切り換えるノズル切換手段を備え、
圧力検出手段で検出された気相部の圧力が上昇傾向に転じたときに、ノズル切換手段が、上記ノズルから送液する受入液が常時液面に到達するように、送液するノズルをより高位置のノズルに切り換えて、各ノズルからの噴流及び随伴液を液面で気相部のガスと接触させて、置換体積以上にガスを凝縮させることを特徴とするＬＮＧ等の受入液の受入装置である。
【００２０】
【発明の実施の形態】
以下、本発明の好適実施の形態を添付図面に基づいて詳述する。
【００２１】
図１は、低温液の受入装置としてＬＮＧサテライト基地を例に示したもので、図３と同じ機能のものは同一符号で説明する。
【００２２】
先ず、貯蔵タンク１０Ａ，１０Ｂは、貯蔵液１１を収容する内槽２５と、その内槽２５を真空断熱層等を介して覆う外槽２６とからなり、全体に縦型円筒状に形成される。
【００２３】
この貯蔵タンク１０Ａ，１０Ｂの頂部には、ＢＯＧのガスライン（又はベントライン）１４が接続され、そのライン１４に圧力調整弁１３Ａ，１３Ｂが接続される。
【００２４】
貯蔵タンク１０Ａ，１０Ｂには、そのタンク１０Ａ，１０Ｂ内の貯蔵液１１の液面を検出する液位検出手段２７Ａ，２７Ｂが設けられ、また気相部１２Ａ，１２Ｂのガス圧力を検出する圧力検出手段２８Ａ，２８Ｂが設けられる。
【００２５】
貯蔵タンク１０Ａ，１０Ｂの底部には、その貯蔵液１１を、利用系に払い出すための払出ライン１８が接続され、その払出ライン１８に、それぞれ貯蔵タンク１０Ａ，１０Ｂの貯蔵液１１を払い出すための開閉制御弁１７Ａ，１７Ｂが接続される。
【００２６】
払出ライン１８には、開閉弁３０を介して加圧気化器１９が接続され、その加圧気化器１９のガスライン３１にガス弁３２が接続される。
【００２７】
また、貯蔵タンク１０Ａ或いは１０Ｂを加圧するために、ガス弁３２と加圧気化器１９間より、貯蔵タンク１０Ａ，１０Ｂの頂部に至る分岐ライン２４が接続され、そのラインに圧力調整弁２９Ａ，２９Ｂが接続され、加圧気化器１９で蒸発されたＢＯＧを分岐ライン２４を通し、圧力調整弁２９Ａ，２９Ｂによりタンク圧力を調整できるようになっている。
【００２８】
貯蔵タンク１０Ａ，１０Ｂには、輸送車１５のタンク１６の液を受け入れるためのボトムフィードライン２１Ａ，２１Ｂが接続され、そのライン２１Ａ，２１Ｂに開閉弁３３Ａ，３３Ｂが接続されると共に受入ライン２０が接続され、その受入ライン２０に受入弁３４が接続される。
【００２９】
この受入弁３４とガスライン３１のガス弁３２とは、受入液の受入時にローディングアーム或いはフレキシブルホース３５，３６を介して輸送車１５のタンク１６と接続される。
【００３０】
さて、本発明においては、貯蔵タンク１０Ａ，１０Ｂ内に、噴出高さの異なる複数のノズル３７，３８，３９が設けられ、その各ノズル３７，３８，３９のライン４０，４１，４２が送液ライン２１Ａ，２１Ｂに接続されると共に、そのライン４０，４１，４２に、ノズル開閉制御弁４４，４５，４６が接続され、液位検出手段２７の検出値に応じてノズル開閉制御弁４４，４５，４６を開閉制御するノズル切換手段４４を設けて構成したものである。
【００３１】
また、貯蔵タンク１０Ａ，１０Ｂには、圧力検出手段２８が設けられ、その圧力検出手段２８の検出値がノズル切換手段４４に入力され、液位検出手段２７の検出値に代えて、或いはこれと併用して貯蔵タンク１０Ａ或いは１０Ｂの圧力が上昇に転じた場合に、ノズル切換手段４４が、ノズル開閉制御弁４４，４５，４６を開閉制御するようにされる。
【００３２】
なお、ボトムフィードライン２１Ａ，２１Ｂには、受入液を貯蔵タンク１０Ａ，１０Ｂに供給するトップフィードライン２３Ａ，２３Ｂが接続され、そのライン２３Ａ，２３Ｂに逆止弁４８Ａ，４８Ｂと開閉弁４９Ａ，４９Ｂが接続される。
【００３３】
次に本発明の作用を説明する。
【００３４】
今、貯蔵タンク１０Ｂの開閉制御弁１７Ｂが開で、その貯蔵タンク１０Ｂが送液運転中で、液が高圧で払出ライン１８に払い出され、貯蔵タンク１０Ａの開閉制御弁１７Ａが閉で、その貯蔵タンク１０Ａに輸送車１５から受入液を受け入れるとして説明する。
【００３５】
この受入時、貯蔵タンク１０Ａは、受入液の受入のために受入可能圧力に前もって落圧され、その圧力が例えば、０．３ＭＰａｇに調整されている。この圧力の調整は、図示していないが、気相部１２ＡのＢＯＧを、他の圧力の低い貯蔵タンク１０の貯蔵液１１に吹き込んだり、或いは系外のガスタンクなどに排出して行う。
【００３６】
受入液の受入の際には、払出ライン１８に払い出された液を、開閉弁３０を介して加圧気化器１９に導入して蒸発させ、そのＢＯＧをガス弁３２、ローディングアーム或いはフレキシブルホース３２を介してタンク１６に導入する。
【００３７】
受入側の貯蔵タンク１０Ａの圧力（約０．３ＭＰａｇ）は、送液中の貯蔵タンク１０Ｂの圧力（約０．５５ＭＰａｇ）より低くしてあるので、輸送車１５のタンク１６の受入液は、フレキシブルホース３５、受入弁３４を介して受入ライン２０に流れ、その受入ライン２０から、ボトムフィードライン２１Ａを介し、ノズルライン４０，４１，４２のいずれかを通り、ノズル３７，３８，３９から貯蔵タンク１０Ａ内に流入する。
【００３８】
ノズル切換手段４４は、液位検出手段２７Ａからその貯蔵タンク１０Ａの貯蔵液１１の液面の高さを検出し、その液位に応じて開閉制御弁４０，４１，４２のいずれかを開とする。この場合、ノズル切換手段４４は、液面が低いときには、開閉制御弁４２を開として、低位置のノズル３９から受入液を液面に向けて噴出し、液面の上昇に伴って開閉制御弁４３，４４を開閉し、低位置のノズル３９から中位置のノズル３８、高位置のノズル３７に順次切り換え制御する。
【００３９】
この際、ノズル切換手段４４は、液面設定値での切り換え前にタンク１０Ａの圧力が上昇に転じた場合は、ノズル切換手段４４により開閉制御弁４０，４１，４２の開閉を液面による切り換えに優先して行う。これにより貯蔵タンク１０Ａの気相部１２Ａの冷却減圧がより確実に行える。
【００４０】
貯蔵タンク１０Ａの液面が高くなった後は、タンク１６内の圧力を低圧まで落圧させるべく、トップフィードライン２３の開閉制御弁４９Ａを開とし、受入液をトップフィードライン２３を通してタンク１０Ａの頂部から受け入れるようにする。その後、タンク１６内のＢＯＧの落圧のために、トップフィードライン２３の開閉制御弁４９Ａを閉じ、低位置のノズル３９の開閉制御弁４７を開として、ＢＯＧをノズル３９から貯蔵タンク１０Ａの液中に吹き込んで吸収させる。
【００４１】
このように、本発明は、貯蔵タンクへ受入液を受け入れる際に、高さの異なるノズル３７，３８，３９を切り換えて、その貯蔵液中からその液面に到達するように受入液を噴流で上向きに噴出して送液することで、気相部１２Ａのガスを冷却してその圧力上昇を防止しながら、しかもタンク１６内の圧力も上げることなく受入ができるようにしたものである。
【００４２】
以下、この理由を説明する。
【００４３】
比重の軽い貯蔵液中に比重の重い液を入れる時、受入液の噴流が常に液面に到達するような噴出速度で噴出することで、すなわち液中に温度（比重）の異なる同一組成の液体を、重力と反対方向にジェット噴流（１〜４ｍ／ｓｅｃ）として順次ノズルから吹き出した時、噴流の比重が貯蔵液より重い場合には、重力による下方への落下速度と噴流速度とが等しくなるまで液中を上昇し、その後は下降する。この場合に、噴流の到達高さ以下に貯蔵液の液面がある時、噴流及び貯蔵タンク下部からの随伴液が液面で気相部のガスと接触する。
【００４４】
受入液の飽和圧力は、通常ガスの平衡圧力より非常に低い（温度が低い）ので、液温でガスが冷却されて凝縮し、液に吸収される。この場合にガス相の置換体積以上にガスが凝縮すれば、気相部の圧力は上昇しないで降下する。
【００４５】
通常、貯蔵タンクの下部のノズルから貯蔵液中に比重の重い液を吹き込んだ場合、噴流の到達高さはフルード数から概算できることが知られている。
【００４６】
貯蔵液をＬＮＧとした時の組成と、比重から求めたノズル吹き出し速度と到達高さの関係の一例は、概略次の通りである。
【００４７】

また貯蔵タンク内での任意の温度の異なる貯蔵液Ａ，Ｂ，Ｃと受入液の温度と比重の関係は次のようになる。
【００４８】

受入液を貯蔵タンクの底部から、ジェット噴流としてタンク内の液に噴出した場合の噴流が到達する概略高さは、次のようになる。
【００４９】

受入液の比重が軽い場合は、浮力により、通常は液面に到達する。
【００５０】
次に、受入液及び噴流で随伴する随伴液が液面に到達し、表面を拡散する液とガスの熱交換量を推算する。推算条件として貯蔵液Ａ（温度−１５３℃）を貯蔵した貯蔵タンクに受入液を噴出するケースを例とし、また貯蔵タンクの直径を３．２ｍとして推算する。
【００５１】

この推算例では、凝縮ガス体積の方が置換体積より大きいので、ガス相圧力は低下することになる。
【００５２】
この圧力低下の傾向は、ノズルからの噴出速度が速く、タンク直径が大きいほど、大きくなる。例えば、直径５ｍの貯蔵タンクの凝縮量は、伝熱面積上から上記の推算値の２．０倍となる。
【００５３】
上記に計算した噴流の到達高さは、理想状態での計算結果であるので、実際には、この６０％の高さと仮定すれば、上記の伝熱量は確実に確保でき、実機のテストでも確認できた。
【００５４】
従って、ノズルから２．５ｍ／ｓｅｃで噴出した場合の噴流の到達高さは、約５ｍとなり、通常の円筒縦型の貯蔵タンクでは、ボトムからトップまでの液面の高さは約１５〜２５ｍであるので、ノズルの本数を高さに応じて設ければよい。
【００５５】
図３は、本発明と従来例におけるＬＮＧの受入量（転送）Ｗに対する貯蔵タンクの圧力Ｐの変化を示したものである。
【００５６】
受入圧力に落圧して貯蔵タンクに、従来のようにトップフィードで受入液を受け入れた場合、曲線ｂで示したように、気相部と接している内槽鋼材を受入液で冷却するため、気相部の圧力が上昇し、その後、受入圧力以下にさがる変化となる。
【００５７】
このように、従来、トップフィードで受入する際には、液頭圧が０．００７〜０．１２ＭＰａ必要とするので、荷卸し時に、液頭圧に見合った高い圧力をかけることが必要になる。通常は受入時の貯蔵タンクは殆ど空に近いので、この液頭圧はボトムフィードに比べて余計に輸送車のタンクを加圧することになる。従って、輸送車のタンクと貯蔵タンクのガス相圧力との間の必要差圧を確保するために貯蔵タンクの圧力を前もって、この分落圧する必要がある。
【００５８】
本発明においては、ボトムフィードで受入液を受け入れるため、曲線ａに示すように、受入圧力以上にタンク内が上昇することがないため、従来のような落圧を必要としないため、運転の幅が広くなると共に無駄に設備外にＢＯＧを排出することがなくなるので、濃縮対策にも有効な方法となる。
【００５９】
また、荷卸し時の圧力を低くできるので加圧量が少なくできるため、加圧ガスが輸送車のタンク内で受入液に凝縮吸収されるガス量も少なくなるため、受入液に入る熱量が少なくなり、受入液の飽和圧力の上昇を抑えることができ、結果として濃縮量を少なくすることができる。
【００６０】
貯蔵タンクのガス相の内槽材は、液層よりかなりスーパーヒートしているが、従来のように貯蔵タンクの上部から受入液を入れると、このスーパヒート部分の全体を、受入液の蒸発潜熱で冷却することになるため、蒸発ガスにより貯蔵タンクのガス相圧力を高めることになるが、本発明のように貯蔵タンクの下部から受入液を入れることで、入った液の顕熱で内槽材を冷却するため、余分な蒸発ガスが発生しないために、圧力を不当に上昇させることがないので、受入圧力も少なくなる。
【００６１】
貯蔵タンク下部からの液が充分に表面で広がる噴流高さは、上述のように２．５ｍ／ｓｅｃで、約５ｍであり、貯蔵タンクの高さの半分以下であり、単純にボトムフィードしたのでは、液面が上昇すると噴流が液面に到達せずに、気相部のガスを凝縮することができなくなり、ガスが圧縮されて圧力が上昇して受入液を受け入ることができなくなるが、本発明のように、液面或いは圧力変化に応じて噴出するノズルの高さを切り換えることで、気相部のガスを冷却凝縮させながら受け入れることが可能となり、受入時の圧力を不当に高くすることなく受け入れすることが可能となる。
【００６２】
以上本実施の形態を説明したが、本発明は上述した実施の形態に限定されることなく種々の変形ができる。例えば、ノズル３７，３８は、貯蔵タンク１０の底部から上方に向けて設ける例で説明したが、ノズル３７，３８は、液面に向けて上方に噴流を噴出できるようにしたものであれば、いかなる形状のものでもよくまた、その本数も噴流速度と貯蔵タンク１０の高さに応じて適宜変更できることは勿論であり、またノズル高さを変更できるようにすれば、１本でもよい。またＬＮＧサテライト基地を例に説明したが、エチレン設備、液体アンモニア設備でも使用できる。さらに輸送車のタンクから貯蔵タンクに送液する例で説明したが、貯蔵タンク間の貯蔵液を送液する場合にも適用できることは勿論である。
【００６３】
【発明の効果】
以上要するに本発明によれば、輸送車などのタンクから貯蔵タンクに受入液を受け入れる際に、貯蔵タンクに高さの異なるノズルを設け、噴流が液面に到達するようにノズルを切り換えて送液することで、気相部のガスを冷却凝縮しながら受入液を貯蔵タンク内に受け入れることができるため、ＢＯＧの排出やタンクの加圧量が少なくても受入が可能となる。
【図面の簡単な説明】
【図１】本発明の一実施の形態を示す図である。
【図２】本発明及び従来例における受入時の貯蔵タンクの圧力変化を示す図である。
【図３】従来例を示す図である。
【符号の説明】
１０Ａ，１０Ｂ貯蔵タンク
１１貯蔵液
１５輸送車
１６タンク
３７，３８，３９ノズル[0001]
BACKGROUND OF THE INVENTION
The present invention accepts LNG for receiving LNG at an LNG satellite base, liquefied ethylene at a liquefied ethylene storage facility, and other liquids whose saturation pressure at room temperature is higher than the atmospheric pressure from a transport vehicle or other tank to a storage tank or the like. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid receiving method and apparatus, and more particularly, to a receiving method and apparatus for receiving liquid such as LNG that can suppress pressure increase in a tank when receiving the received liquid.
[Prior art]
LNG reception at a conventional LNG satellite base will be described with reference to FIG.
[0003]
In FIG. 3, 10A and 10B are storage tanks for storing LNG, liquefied ethylene, and other storage liquids 11 whose saturation pressure at room temperature is higher than the atmospheric pressure, and are formed into a vertical double cylinder due to site problems. .
[0004]
The storage liquid 11 stored in the storage tanks 10 A and 10 B is maintained at the operating pressure by the gas from the pressurized vaporizer 19. When the operating pressure rises due to heat input or the like at the pressure regulating valves 13A and 13B connected to the gas line (or vent line) 14, the gas phase sections 12A and 12B discharge the gas to store the storage liquid 11 The operating pressure (about 0.55 to 6 MPag) for discharging the gas is held. The BOG that has become higher than the operating pressure due to heat input during storage is appropriately discharged to the gas line (or vent line) 14 via the pressure regulating valves 13A and 13B.
[0005]
Although the storage tanks 10A and 10B are omitted in the drawing, a plurality of storage tanks 10A, 10B, for example, have a low liquid level, for example, one storage tank 10A, and the storage tank 10A receives LNG from the tank 16 of the transport vehicle 15 such as a tank truck. The tank 16 is pressurized and fed, but in the pressure receiving operation of the transport vehicle, the pressure of the storage tank 10A at the time of receiving is reduced to about 0.3 MPa because it is restricted by the design pressure of the vehicle. Driven. This pressure reduction is performed by discharging the BOG in the gas phase portion 12A by an appropriate means.
[0006]
After reducing the pressure of the storage tank 10A, the open / close control valve 17B of the storage tank 10B during the liquid feeding operation is opened, the storage liquid 11 is introduced into the pressurized vaporizer 19 via the discharge line 18, and the gas is evaporated. By introducing the gas into the tank 16 through the gas valve 32 and pressurizing the tank 16, the liquid in the tank 16 is received from the receiving valve 34 into the storage tank 10 A through the receiving line 20.
[0007]
When this LNG is received, if the liquid is fed through the nozzle 22 from the bottom feed line 21 connected to the bottom of the storage tank 10A from the receiving line 20, the gas in the gas phase section 12A is compressed to a high pressure by the filling liquid. As long as the gas from the section 12A is not discharged, it cannot be received. Usually, since the pressure of the gas line 14 is higher than the pressure of the gas phase portion 12A at the time of acceptance, the replacement gas in the gas phase portion 12A cannot be discharged to the gas line 14 as it is. Further, even when the replacement gas in the tank 10A at the time of acceptance can be discharged to the gas line 14, discharging BOG outside the facility is not a preferable operation method because it causes the concentration of the remaining liquid in the tank 10A.
[0008]
Furthermore, in the case of LNG, since the main component of BOG is methane, the calorific value is small, so the heat must be increased. Since the amount of exhaust at the time of acceptance temporarily increases, the heat control equipment is also correspondingly much larger than the normal equipment capacity, resulting in uneconomical equipment.
[0009]
Therefore, the top feed line 23 is received from the top of the storage tank 10A.
[0010]
This method prevents the gas in the gas phase portion 12A from being compressed and pressurized when the liquid is filled. That is, the gas phase in a state of pressure (temperature) higher than the saturation pressure (temperature) of the receiving liquid accepts the receiving liquid, thereby absorbing and liquefying the gas with a low-temperature liquid and reducing the amount of gas, so that the gas phase portion 12A Boosting is prevented.
[0011]
[Problems to be solved by the invention]
However, as described above, the storage tanks 10A and 10B have a cylindrical vertical type. When liquid is received from the top, the liquid head pressure up to the top is added regardless of the liquid level of the tank. Since the 15 tanks 16 must be pressurized, when the liquid level of the storage tanks 10A and 10B to be received is low, the tanks 16 are excessively pressurized, and a problem arises in that they cannot be received due to the pressure resistance of the tanks 16.
[0012]
Further, the gas phase sections 12A and 12B have a high normal temperature for operation. Further, the heat transfer from the steel material, which is the inner tank material of the gas phase portion, is radiant heat transfer to the liquid phase surface, and therefore is considerably higher than the liquid temperature. When the receiving liquid comes into contact with the steel material of the inner tank in such a state, BOG evaporates violently and the pressure rises. This temporary boosting of the gas phase portions 12A and 12B at the initial stage of reception is a phenomenon often seen.
[0013]
For this reason, in an operation such as transfer between tanks where there is no margin for the acceptance differential pressure, the differential pressure may be insufficient and the operation may not be continued. In the case of a tank that receives a small number of times, the amount of BOG is larger than the amount of liquid received. Therefore, this BOG is once dropped into another tank such as a water tank and discharged outside the equipment. In the case, since most of the components of BOG are light components composed of methane, heavy components such as ethane and butane in the stock solution are relatively increased and cause concentration, which is not preferable.
[0014]
When the storage liquid 11 in the storage tank 10A or 10B is dispensed to the utilization system, the liquid is introduced into the pressurized vaporizer 19 and vaporized, and the storage tank 10A or 29B is supplied from the line 23 by the pressure regulating valve 29A or 29B. The operating pressure is maintained by supplying BOG to 10B.
[0015]
Therefore, the object of the present invention is to solve the above-mentioned problems and to increase the pressure of the gas phase part of the storage tank without increasing the pressure of the tank to which the liquid is fed when receiving the low temperature liquid into the storage tank. An object of the present invention is to provide a receiving method and apparatus for receiving liquid such as LNG that can be fed without any problem.
[0016]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 is directed to the storage liquid in the storage tank during the liquid feeding operation after dropping the pressure in the vertical double cylindrical storage tank that receives the receiving liquid such as LNG. In the method of sending out and vaporizing this , sending it to a tank loaded with a receiving liquid such as LNG such as a transport vehicle , pressurizing the tank, and receiving the receiving liquid in the tank into the depressurized storage tank. The receiving liquid is sent as a jet upward from the storage liquid toward the liquid level so that the receiving liquid always reaches the liquid level of the storage tank that receives the liquid . This is a method for receiving a receiving liquid such as LNG , which is brought into contact with a gas so as to condense the gas beyond the substitution volume .
[0017]
In the invention of claim 2, a plurality of nozzles having different ejection heights are installed in the storage tank, and the nozzles having different heights are switched to feed liquid according to the rise in the liquid level. It is a receiving method of receiving liquids, such as LNG described.
[0018]
In the third aspect of the invention, after the pressure in the vertical double cylindrical storage tank that receives the receiving liquid such as LNG is dropped, the storage liquid in the storage tank during the liquid feeding operation is discharged and vaporized. In a device for sending a receiving liquid such as LNG, such as a transport vehicle , to a tank loaded with pressure, pressurizing the tank, and receiving the receiving liquid in the tank into the reduced pressure storage tank, the liquid level of the storage tank receiving the receiving liquid The liquid level detecting means for detecting the liquid level, the nozzle provided at the bottom from the bottom of the storage tank and having a different ejection height for feeding the received liquid as a jet toward the liquid surface, and the liquid level detecting means. Nozzle switching means for switching the nozzle according to the liquid level, and the nozzle switching means according to the liquid level detected by the liquid level detection means so that the liquid received from the nozzle always reaches the liquid level. On the nozzle, low LNG, etc., which is switched from the nozzle at the position to the nozzle at the higher position in order, and the jet and the accompanying liquid from each nozzle are brought into contact with the gas in the gas phase at the liquid level to condense the gas beyond the replacement volume. This is a liquid receiving device.
[0019]
In the fourth aspect of the present invention, after the pressure in the vertical double cylindrical storage tank that receives the receiving liquid such as LNG is dropped, the storage liquid in the storage tank during the liquid feeding operation is discharged and vaporized. In a device that sends a receiving liquid such as LNG such as a transport vehicle to a tank loaded with pressure, pressurizes the tank, and receives the receiving liquid in the tank into the depressurized storage tank. The pressure detection means for detecting, the nozzles respectively provided upward from the bottom of the storage tank, and for sending the received liquid as a jet flow toward the liquid surface, and the pressure detected by the pressure detection means Provided with nozzle switching means for switching the nozzle when turning to an upward trend,
When the pressure in the gas phase portion detected by the pressure detecting means starts to increase, the nozzle switching means further increases the nozzle for feeding liquid so that the liquid received from the nozzle always reaches the liquid level. Receiving a receiving liquid such as LNG, which is characterized by switching to a high nozzle and bringing the jet and accompanying liquid from each nozzle into contact with the gas in the gas phase at the liquid level to condense the gas beyond the replacement volume. Device.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0021]
FIG. 1 shows an example of an LNG satellite base as a cryogenic liquid receiving device. Components having the same functions as those in FIG.
[0022]
First, the storage tanks 10A and 10B are composed of an inner tank 25 that stores the storage liquid 11 and an outer tank 26 that covers the inner tank 25 with a vacuum heat insulating layer or the like, and is formed in a vertical cylindrical shape as a whole. .
[0023]
BOG gas lines (or vent lines) 14 are connected to the tops of the storage tanks 10A and 10B, and pressure control valves 13A and 13B are connected to the lines 14.
[0024]
The storage tanks 10A and 10B are provided with liquid level detection means 27A and 27B for detecting the liquid level of the storage liquid 11 in the tanks 10A and 10B, and pressure detection for detecting the gas pressure of the gas phase portions 12A and 12B. Means 28A, 28B are provided.
[0025]
A discharge line 18 for discharging the storage liquid 11 to the utilization system is connected to the bottom of the storage tanks 10A and 10B, and the storage liquid 11 of the storage tanks 10A and 10B is discharged to the discharge line 18 respectively. Open / close control valves 17A and 17B are connected.
[0026]
A pressurized vaporizer 19 is connected to the discharge line 18 via an on-off valve 30, and a gas valve 32 is connected to a gas line 31 of the pressurized vaporizer 19.
[0027]
Further, in order to pressurize the storage tank 10A or 10B, a branch line 24 is connected between the gas valve 32 and the pressurized vaporizer 19 to the top of the storage tanks 10A and 10B, and pressure adjusting valves 29A and 29B are connected to the lines. Are connected, and the BOG evaporated by the pressurized vaporizer 19 is passed through the branch line 24 so that the tank pressure can be adjusted by the pressure adjusting valves 29A and 29B.
[0028]
The storage tanks 10A and 10B are connected to the bottom feed lines 21A and 21B for receiving the liquid in the tank 16 of the transport vehicle 15, and the lines 21A and 21B are connected to the on-off valves 33A and 33B and the receiving line 20 is connected. The receiving valve 34 is connected to the receiving line 20.
[0029]
The receiving valve 34 and the gas valve 32 of the gas line 31 are connected to the tank 16 of the transport vehicle 15 via a loading arm or flexible hoses 35 and 36 when receiving the receiving liquid.
[0030]
In the present invention, a plurality of

nozzles

37, 38, 39 having different ejection heights are provided in the storage tanks 10A, 10B, and the

lines

40, 41, 42 of the

nozzles

37, 38, 39 are fed. The nozzle opening /

closing control valves

44, 45, 46 are connected to the lines 21 A, 21 B and the

lines

40, 41, 42, and the nozzle opening /

closing control valves

44, 45 according to the detection value of the liquid level detection means 27. , 46 is provided with nozzle switching means 44 for controlling opening and closing.
[0031]
Further, the storage tanks 10A and 10B are provided with a pressure detection means 28, and the detection value of the pressure detection means 28 is input to the nozzle switching means 44, and instead of the detection value of the liquid level detection means 27, or In combination, when the pressure in the storage tank 10A or 10B starts to increase, the nozzle switching means 44 controls the nozzle opening /

closing control valves

44, 45, and 46 to open and close.
[0032]
The bottom feed lines 21A and 21B are connected to top feed lines 23A and 23B for supplying the received liquid to the storage tanks 10A and 10B, and check valves 48A and 48B and on-off valves 49A and 49B are connected to the lines 23A and 23B. Is connected.
[0033]
Next, the operation of the present invention will be described.
[0034]
Now, the open / close control valve 17B of the storage tank 10B is open, the storage tank 10B is in a liquid feeding operation, the liquid is discharged to the discharge line 18 at a high pressure, and the open / close control valve 17A of the storage tank 10A is closed. A description will be given assuming that the storage tank 10A receives the received liquid from the transport vehicle 15.
[0035]
At the time of reception, the storage tank 10A is dropped in advance to an acceptable pressure for receiving the reception liquid, and the pressure is adjusted to, for example, 0.3 MPag. Although not shown, the pressure is adjusted by blowing the BOG of the gas phase section 12A into the storage liquid 11 of another storage tank 10 having a low pressure or discharging it to a gas tank outside the system.
[0036]
When receiving the received liquid, the liquid discharged to the discharge line 18 is introduced into the pressurized vaporizer 19 via the on-off valve 30 and evaporated, and the BOG is gas valve 32, loading arm or flexible hose. It is introduced into the tank 16 via 32.
[0037]
Since the pressure (about 0.3 MPag) of the storage tank 10A on the receiving side is lower than the pressure (about 0.55 MPag) of the storage tank 10B during liquid feeding, the liquid received in the tank 16 of the transport vehicle 15 is flexible. It flows into the receiving line 20 through the hose 35 and the receiving valve 34, and passes through the

nozzle line

40, 41, 42 from the receiving line 20 through the bottom feed line 21A, and from the

nozzles

37, 38, 39 to the storage tank. Flows into 10A.
[0038]
The nozzle switching means 44 detects the height of the liquid level of the storage liquid 11 in the storage tank 10A from the liquid level detection means 27A, and opens any of the open /

close control valves

40, 41, 42 according to the liquid level. To do. In this case, when the liquid level is low, the nozzle switching means 44 opens the open / close control valve 42 to eject the received liquid from the low-position nozzle 39 toward the liquid level, and as the liquid level rises, the open / close control valve 42 opens. The nozzles 43 and 44 are opened and closed, and the switching is sequentially performed from the low-position nozzle 39 to the middle-position nozzle 38 and the high-position nozzle 37.
[0039]
At this time, if the pressure in the tank 10A starts to increase before switching at the liquid level setting value, the nozzle switching means 44 switches the opening /

closing control valves

40, 41, and 42 by the liquid level by the nozzle switching means 44. Priority is given to. Thereby, the cooling pressure reduction of the gas phase part 12A of the storage tank 10A can be performed more reliably.
[0040]
After the liquid level of the storage tank 10 A becomes high, the open / close control valve 49 A of the top feed line 23 is opened to reduce the pressure in the tank 16 to a low pressure, and the received liquid passes through the top feed line 23 to the tank 10 A. Accept from the top. Thereafter, in order to reduce the pressure of BOG in the tank 16, the open / close control valve 49A of the top feed line 23 is closed, the open / close control valve 47 of the low-position nozzle 39 is opened, and the BOG is discharged from the nozzle 39 to the liquid in the storage tank 10A. Inhale and absorb.
[0041]
As described above, the present invention switches the

nozzles

37, 38, and 39 having different heights when receiving the receiving liquid into the storage tank, and jets the receiving liquid to reach the liquid level from the stored liquid. By jetting upward and feeding the liquid, the gas in the gas phase portion 12A is cooled to prevent an increase in pressure, and the pressure can be received without increasing the pressure in the tank 16.
[0042]
Hereinafter, the reason will be described.
[0043]
When a liquid with a high specific gravity is put into a storage liquid with a low specific gravity, the liquid of the same composition with different temperature (specific gravity) in the liquid is ejected at a jet speed that always causes the jet of the receiving liquid to reach the liquid surface. When the specific gravity of the jet is heavier than the stock solution when the jet is blown out sequentially from the nozzle as a jet jet (1-4 m / sec) in the direction opposite to gravity, the downward velocity and jet velocity due to gravity are equal. Ascends in the liquid until it descends. In this case, when the liquid level of the storage liquid is below the arrival height of the jet, the accompanying liquid from the jet and the lower part of the storage tank comes into contact with the gas in the gas phase at the liquid level.
[0044]
Since the saturation pressure of the receiving liquid is usually much lower than the equilibrium pressure of the gas (the temperature is low), the gas is cooled and condensed at the liquid temperature and absorbed by the liquid. In this case, if the gas condenses more than the replacement volume of the gas phase, the pressure in the gas phase portion does not increase but falls.
[0045]
In general, when a liquid having a high specific gravity is blown into the storage liquid from the nozzle at the bottom of the storage tank, it is known that the reaching height of the jet can be estimated from the fluid number.
[0046]
An example of the relationship between the composition when the stock solution is LNG, the nozzle blowing speed determined from the specific gravity, and the reaching height is as follows.
[0047]

Further, the relationship between the storage liquids A, B, and C having different temperatures in the storage tank and the temperature of the receiving liquid and the specific gravity is as follows.
[0048]

The approximate height at which the jet reaches when the incoming liquid is jetted from the bottom of the storage tank as a jet jet into the liquid in the tank is as follows.
[0049]

When the specific gravity of the receiving liquid is light, it usually reaches the liquid level due to buoyancy.
[0050]
Next, the amount of heat exchange between the receiving liquid and the accompanying liquid accompanying the jet flow reaches the liquid surface and the liquid and gas diffused on the surface are estimated. As an estimation condition, a case where the receiving liquid is jetted into the storage tank storing the storage liquid A (temperature −153 ° C.) is taken as an example, and the diameter of the storage tank is estimated to be 3.2 m.
[0051]

In this estimation example, since the condensed gas volume is larger than the replacement volume, the gas phase pressure is lowered.
[0052]
The tendency of this pressure drop increases as the ejection speed from the nozzle increases and the tank diameter increases. For example, the condensation amount of a storage tank having a diameter of 5 m is 2.0 times the estimated value from the viewpoint of the heat transfer area.
[0053]
The arrival height of the jet calculated above is the result of calculation in an ideal state. In fact, assuming that this height is 60%, the above heat transfer amount can be reliably ensured and confirmed by actual machine tests. did it.
[0054]
Therefore, the height of the jet flow when ejected from the nozzle at 2.5 m / sec is about 5 m. In a normal cylindrical vertical storage tank, the liquid level from the bottom to the top is about 15 to 25 m. Therefore, the number of nozzles may be provided according to the height.
[0055]
FIG. 3 shows a change in the storage tank pressure P with respect to the amount of LNG received (transfer) W in the present invention and the conventional example.
[0056]
When the receiving liquid is received by top feed as in the conventional case by dropping the pressure to the receiving pressure, as shown by the curve b, in order to cool the inner tank steel material in contact with the gas phase part with the receiving liquid, The pressure in the gas phase rises and then changes to a level below the acceptance pressure.
[0057]
Thus, conventionally, when receiving by top feed, the liquid head pressure needs to be 0.007 to 0.12 MPa, so it is necessary to apply a high pressure corresponding to the liquid head pressure at the time of unloading. . Usually, since the storage tank at the time of reception is almost empty, this liquid head pressure pressurizes the tank of the transport vehicle more than the bottom feed. Therefore, in order to ensure the necessary differential pressure between the tank of the transport vehicle and the gas phase pressure of the storage tank, it is necessary to reduce the pressure of the storage tank in advance.
[0058]
In the present invention, since the receiving liquid is received by bottom feed, the inside of the tank does not rise above the receiving pressure as shown by the curve a. Since the BOG is not exhausted outside the facility as the size increases, it is an effective method for concentration measures.
[0059]
In addition, since the pressure during unloading can be reduced, the amount of pressurization can be reduced, and the amount of gas that is condensed and absorbed in the receiving liquid in the tank of the transport vehicle is also reduced, so the amount of heat entering the receiving liquid is small. Thus, an increase in the saturation pressure of the receiving liquid can be suppressed, and as a result, the amount of concentration can be reduced.
[0060]
The tank material in the gas phase of the storage tank is considerably superheated from the liquid layer, but when the incoming liquid is introduced from the upper part of the storage tank as in the conventional case, the entire superheated part is caused by the latent heat of vaporization of the incoming liquid. Since it will cool, the gas phase pressure of the storage tank will be increased by evaporating gas. However, as in the present invention, by receiving the liquid received from the lower part of the storage tank, the inner tank material is sensible by the sensible heat of the liquid. Since no excessive evaporating gas is generated in order to cool the gas, the pressure is not increased unduly, and the receiving pressure is also reduced.
[0061]
The height of the jet from which the liquid from the lower part of the storage tank spreads sufficiently on the surface was 2.5 m / sec, about 5 m as described above, which was less than half the height of the storage tank, and was simply bottom fed. However, when the liquid level rises, the jet does not reach the liquid level and the gas in the gas phase portion cannot be condensed, and the gas is compressed and the pressure rises so that the received liquid cannot be received. As in the present invention, by switching the height of the nozzle to be ejected according to the liquid level or pressure change, it becomes possible to receive the gas in the gas phase part while cooling and condensing, and the pressure at the time of reception is unreasonably high. It becomes possible to accept without doing.
[0062]
Although the present embodiment has been described above, the present invention can be variously modified without being limited to the above-described embodiment. For example, the

nozzles

37 and 38 have been described in the example provided upward from the bottom of the storage tank 10, but the

nozzles

37 and 38 can be jetted upward toward the liquid level, Of course, any shape can be used, and the number of the nozzles can be appropriately changed according to the jet velocity and the height of the storage tank 10, and can be one if the nozzle height can be changed. Moreover, although the LNG satellite base was demonstrated to the example, it can be used also in ethylene equipment and liquid ammonia equipment. Furthermore, although the example in which liquid is supplied from the tank of the transport vehicle to the storage tank has been described, it is needless to say that the present invention can be applied to the case where the storage liquid is supplied between the storage tanks.
[0063]
【The invention's effect】
In short, according to the present invention, when receiving liquid from a tank such as a transport vehicle into a storage tank, a nozzle having a different height is provided in the storage tank, and the liquid is transferred by switching the nozzle so that the jet reaches the liquid level. By doing so, the accepting liquid can be received in the storage tank while cooling and condensing the gas in the gas phase portion, so that the accepting is possible even if the BOG is discharged or the pressurized amount of the tank is small.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a change in pressure of a storage tank at the time of receiving in the present invention and a conventional example.
FIG. 3 is a diagram showing a conventional example.
[Explanation of symbols]
10A, 10B Storage tank 11 Storage liquid 15 Transport vehicle 16

Tank

37, 38, 39 Nozzle

Claims

After dropping the pressure in the vertical double cylindrical storage tank that receives the liquid received, such as LNG, the liquid stored in the storage tank during the liquid feeding operation is discharged and vaporized, and this is converted into LNG such as transport vehicles. In the method of sending the pressurized liquid to the tank where the incoming liquid is loaded, pressurizing the tank, and receiving the incoming liquid in the tank into the reduced pressure storage tank, the incoming liquid always reaches the liquid level of the storage tank that receives the incoming liquid. The receiving liquid is sent from the stored liquid upward as a jet toward the liquid level, and the jet and accompanying liquid are brought into contact with the gas in the gas phase at the liquid level to condense the gas beyond the substitution volume. An accepting method for accepting liquid such as LNG.

The LNG according to claim 1, wherein a plurality of nozzles having different ejection heights are installed in the storage tank, and the nozzles having different heights are switched in accordance with an increase in liquid level or pressure. How to receive liquid.

After dropping the pressure in the vertical double cylindrical storage tank that receives the liquid received, such as LNG, the liquid stored in the storage tank during the liquid feeding operation is discharged and vaporized, and this is converted into LNG such as transport vehicles. Level detecting means for detecting the liquid level of the storage tank that receives the received liquid in the apparatus that sends the received liquid to the tank loaded with pressure and pressurizes the tank and receives the received liquid in the tank in the storage tank that has been reduced in pressure. According to the liquid level detected by the liquid level detection means and the nozzles provided respectively upward from the bottom of the storage tank, and sending the received liquid as a jet toward the liquid level. Nozzle switching means for switching nozzles,
According to the liquid level detected by the liquid level detection means, the nozzle switching means switches the nozzle from the low position nozzle to the high position nozzle in order so that the liquid received from the nozzle always reaches the liquid level. A receiving device for receiving liquid such as LNG, wherein the jet flow from each nozzle and the accompanying liquid are brought into contact with the gas in the gas phase at the liquid level to condense the gas beyond the replacement volume.

After dropping the pressure in the vertical double cylindrical storage tank that receives the liquid received, such as LNG, the liquid stored in the storage tank during the liquid feeding operation is discharged and vaporized, and this is converted into LNG such as transport vehicles. Pressure detecting means for detecting the pressure of the gas phase portion of the storage tank in a device for sending the received liquid to the tank loaded with the pressure and pressurizing the tank and receiving the received liquid in the tank in the reduced storage tank; When the pressure detected by the pressure detection means is changed to an upward trend, the nozzles are provided respectively upward from the bottom of the storage tank and send the received liquid as a jet toward the liquid level and the jet height is different. And nozzle switching means for switching the nozzles,
When the pressure in the gas phase portion detected by the pressure detecting means starts to increase, the nozzle switching means further increases the nozzle for feeding liquid so that the liquid received from the nozzle always reaches the liquid level. Receiving a receiving liquid such as LNG, which is characterized by switching to a high nozzle and bringing the jet and accompanying liquid from each nozzle into contact with the gas in the gas phase at the liquid level to condense the gas beyond the replacement volume. apparatus.