JP4684497B2 - Air fin type vaporizer for liquefied natural gas - Google Patents
Air fin type vaporizer for liquefied natural gas Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、液化天然ガス（ＬＮＧ）用のエアフィン式気化装置に関する。
【０００２】
【従来の技術】
液化天然ガスの取扱量の少ないサテライト基地（都市ガスの製造及び供給基地）では、大気を熱源とする液化天然ガス用エアフィン式気化装置が主流として使用されている。この気化装置は、液化天然ガスの蒸発部と過熱部（＝加温部）から構成されており、液化天然ガスの蒸発、過熱（＝加温）に必要な熱を大気から得るため、運転コストがほとんどかからないという利点を有する。この気化装置で、熱源である大気の供給方式には自然通風する方式と強制通風する方式とがある。
【０００３】
図１〜２は、強制通風方式による液化天然ガス用エアフィン式気化装置の概略を示す図である。まず、図１の形式では、蒸発部の熱交換器と過熱部の熱交換器が容器（ケーシング）内に配置されて構成される。蒸発部熱交換器では、フィンを付けた複数の伝熱管（管状熱交換器）が縦方向に配置され、それぞれ上下のヘッダー管に連結されている。この伝熱管は例えば押出成形によりフィンと管を一体に形成することができる。また、過熱部熱交換器では、フィンを付けた複数の伝熱管（管状熱交換器）が縦方向に配置され、各伝熱管は上部及び下部でＵベント管を介して連結されている。
【０００４】
ケーシングの下部には大気吸入口が設けられ、ケーシングの上部には蒸発部熱交換器及び過熱部熱交換器に対応してそれぞれ強制通風用のファンが配置されている。強制通風用ファンにより大気を吸引し、ケーシング内を上方に流通させることで、蒸発部熱交換器で液化天然ガスを加熱して蒸発させ、ここで蒸発した天然ガス（ＮＧ）を過熱部熱交換器で加温する。蒸発部熱交換器で蒸発した天然ガスは連結配管により過熱部熱交換器に供給される。
【０００５】
図１のとおり、この気化装置における蒸発部熱交換器の上部と過熱部熱交換器の上部は同一高さすなわち同一水準に配置され、両者を連結する配管（連結配管）は、水平すなわち同一水準に配置されている。そして、液化天然ガス、蒸発天然ガスの流れ方向は、蒸発部熱交換器内ではアップフロー、過熱部熱交換器内では上下のＵベント部で上下に折返すアップフローとダウンフローの交互となっている。
【０００６】
操作時において、液化天然ガス（ＬＮＧ）は、蒸発部熱交換器の下部からヘッダー管を介して各伝熱管に供給され、各伝熱管中を上昇しながら大気により加熱されて蒸発した後、上部のヘッダー管から連結配管を経て過熱部熱交換器の上部から供給されて過熱部熱交換器で加温され、天然ガス（ＮＧ）として導出される。得られた天然ガスは、ＬＰＧ（液化石油ガス）の添加による熱量調整を経て都市ガスとされ、需要家に供給される。
【０００７】
次に、図２の形式は、基本的には図１の形式のものと同様であるが、ここでは過熱部熱交換器として上下数段に水平に配置された伝熱管（管状熱交換器）を用い、過熱部熱交換器の加熱に自らの製造ガス、すなわち天然ガスを燃焼して得た温風を用いる点で図１の形式のものと異なる。図２のとおり、過熱部熱交換器の出口導管から製造ガスを分岐させ、バーナーに供給して空気により燃焼させる。そして、生成燃焼ガスを過熱部熱交換器の下部に供給して過熱部熱交換器を加熱する。
【０００８】
【発明が解決しようとする課題】
ところで、上記のような液化天然ガス用エアフィン式気化装置は、通常、季節や昼夜を問わず作動される。本発明者らがその作動状況を詳細に観察したところ、冬期や夜明けなど大気温度が低いときに、過熱部熱交換器を経て得られる製造ガス、すなわち天然ガスの組成が変化して熱量変動が生じ、これがＬＰＧの添加による熱量調整を経て製造される都市ガスの品質に悪影響を与えることが分かった。都市ガスの熱量が変化すると、燃焼性の面で問題となり、都市ガスの製造を停止する必要が生じ、需要家への影響を生じることになる。
【０００９】
そこで、本発明は、液化天然ガス用エアフィン式気化装置において生じる上記問題を解決し、その作動時に季節や昼夜を問わず、製造ガスすなわち天然ガスの組成変化を無くし、組成変化に基づく熱量変動を無くして、常時所望、所定品質の都市ガスを供給し得るようにしてなる液化天然ガス用エアフィン式気化装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明は、液化天然ガスの蒸発部熱交換器上部と過熱部熱交換器上部がヘッダー管を介して連結配管により連結されてなる液化天然ガス用エアフィン式気化装置において、蒸発部熱交換器からの該連結配管をダウンフローとなるよう過熱部熱交換器に連結してなることを特徴とする液化天然ガス用エアフィン式気化装置を提供する。
【００１１】
また、本発明は、液化天然ガスの蒸発部熱交換器上部と過熱部熱交換器上部がヘッダー管を介して連結配管により連結されてなる液化天然ガス用エアフィン式気化装置において、過熱部熱交換器上部の高さを蒸発部熱交換器上部より低くして、該連結配管をその中を流通する天然ガスがダウンフローとなるよう過熱部熱交換器に連結してなることを特徴とする液化天然ガス用エアフィン式気化装置を提供する。
【００１２】
さらに、本発明は、液化天然ガスの蒸発部熱交換器上部と過熱部熱交換器上部がヘッダー管を介して連結配管により連結されてなる液化天然ガス用エアフィン式気化装置において、過熱部熱交換器の構造をその中を流通する天然ガスがアップフローとならない構造に構成してなることを特徴とする液化天然ガス用エアフィン式気化装置を提供する。
【００１３】
【発明の実施の形態】
本発明の液化天然ガス用エアフィン式気化装置は、その基本的構成として、液化天然ガスの蒸発部熱交換器と過熱部熱交換器からなり、両熱交換器の上部でヘッダー管を介して配管（連結配管）により連結して構成される。蒸発部熱交換器は大気により加熱され、過熱部熱交換器は▲１▼大気、▲２▼自らの製造ガスすなわち天然ガスを燃焼して得た温風、あるいは▲３▼温水により加熱される。液化天然ガスは蒸発部熱交換器で蒸発し、該連結配管を通して過熱部熱交換器に導入され、ここで加温される。
【００１４】
前述のとおり、大気温度が低いときに、過熱部熱交換器を経て得られる天然ガスの組成が変化して熱量変動が生じ、熱量調整して製造される都市ガスの品質に悪影響を与えることが分かった。この熱量変動の原因についてさらに観察、追求したところ、大気温度が低いときに、過熱部熱交換器に流入した未蒸発の液化天然ガスが、過熱部熱交換器でダウンフローからアップフローに折り返すとき、下端部のＵベント部に滞留し、その滞留量がある程度の量になると流体力の変化により押し流され、蒸発するために発生することが分かった。また、上記滞留現象は水平に配置された蒸発部熱交換器から過熱部熱交換器への連結配管中でも生じることが分かった。
【００１５】
すなわち、液化天然ガスは、メタンを主成分とするが、プロパン、ブタン、ペンタンなどの重質炭化水素ガスが含まれている。これを蒸発させ、加温するに際して、上記のように大気温度が低いとき、蒸発部熱交換器、過熱部熱交換器を経て得られる天然ガスに組成変化が生じるのは、水平連結配管中や過熱部熱交換器下端部のＵベント部に未蒸発の重質炭化水素ガスが滞留することによるものである。
【００１６】
そこで、本発明においては、上記のような滞留を無くするために、該連結配管をダウンフローに配置する。連結配管をダウンフローに配置する仕方としては、（１）過熱部熱交換器の高さを蒸発部熱交換器より低く配置する、すなわち過熱部熱交換器上部を蒸発部熱交換器上部より低くする、（２）該連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させて配置する、（３）上記（１）及び（２）の配置を併せて行う等の態様で行うことができる。これにより蒸発部熱交換器からの未蒸発の液化天然ガスが連結配管中及び過熱部熱交換器中に滞留するのを防止し、過熱部熱交換器を経て得られる天然ガスの組成変化を回避して、その熱量変動を防止することができる。
【００１７】
また、本発明においては、前記のような滞留を無くするために、過熱部熱交換器自体の構造をアップフローとならない構造とする。過熱部熱交換器自体の構造をアップフローとならない構造とする仕方としては、（１）過熱部熱交換器の伝熱管を水平に配置する、（２）過熱部熱交換器の伝熱管をダウンフローとなるように（すなわち伝熱管中を流通する天然ガスの流れを下降流となるように）配置する等の態様で行うことができる。これにより未蒸発の液化天然ガスが過熱部熱交換器中に滞留するのを防止し、過熱部熱交換器を経て得られる天然ガスの組成変化を回避して、その熱量変動を防止することができる。
【００１８】
図３〜８は本発明の態様例を示す図である。図３は、前述図１に対応する気化装置に本発明を適用した態様である。図３のとおり、過熱部熱交換器の高さを蒸発部熱交換器より低く配置し、すなわち過熱部熱交換器上部を蒸発部熱交換器上部より低くし、また過熱部熱交換器として、上下のヘッダー管に連結した複数個の、フィン付き伝熱管を縦方向に配置し、連結配管からの天然ガスが下方向のみに流れるように構成している。
【００１９】
図４は、図３の態様において、ケーシング中に配置された蒸発部熱交換器と過熱部熱交換器をその間に隔壁を設けて、それぞれを別の空間に配置した態様である。これら図３〜４の態様においては、連結配管からの天然ガスが過熱部熱交換器中下方向のみに流れるように構成していることにより、未蒸発の液化天然ガスが過熱部熱交換器中に滞留するのを防止するとともに、過熱部熱交換器の高さを蒸発部熱交換器より低く配置していることにより、連結配管内に未蒸発の液化天然ガスが滞留するのを防止することができる。
【００２０】
また、図１のように、従来では、各伝熱管は上下でＵベント管で連結され、Ｕベント管は伝熱管に対して溶接により結合される。このため、溶接部が存在するＵベント部で低温液の滞留が繰り返されると、温度変化の繰り返しにより溶接部での繰り返し熱応力が発生し、これが過熱部熱交換器の耐久性を損う原因となっていたが、本発明においては、伝熱管中での低温液の滞留が防止されるので、その耐久性を向上させることができる。
【００２１】
図５は、図３の構成に加えて、連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させた態様である。図５のとおり、連結配管自体を下降傾斜させ蒸発部熱交換器からのガスがダウンフローとなるように配置している。これにより、図３〜４の場合と同じく、未蒸発の液化天然ガスが過熱部熱交換器中に滞留するのを防止するとともに、連結配管内に未蒸発の液化天然ガスが滞留するのをより効果的に防止することができる。
【００２２】
図６は、過熱部熱交換器の加熱に自らの製造ガスを燃焼して得た温風を用いる点では図２の気化装置と同じである。図６のとおり、過熱部熱交換器の高さを蒸発部熱交換器より低く配置し、また過熱部熱交換器中でガスがアップフローとならない構造として過熱部熱交換器のフィン付き伝熱管を上下複数段、水平に配置している。過熱部熱交換器の高さを蒸発部熱交換器より低くし、且つ、過熱部熱交換器のフィン付き伝熱管を水平に配置しているので、連結配管中での未蒸発の液化天然ガスの滞留を防止するとともに、過熱部熱交換器中での未蒸発の液化天然ガスの滞留を防止することができる。
【００２３】
なお、過熱部熱交換器の加熱源としては、上記のように温風を用いるのに代えて、温水を用いるようにすることもできる。この場合、過熱部熱交換器としてはガスが流通する伝熱管の外面に温水を流通させる形式など、周知の気液熱交換器を用いることができ、また、温水生成用の熱源としては、自らの製造ガスを燃焼して得た燃焼ガスのほか、都市ガスの燃焼ガスなど他の熱源を用いてもよい。
【００２４】
図７は、図６の構成に加えて、連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させて配置した態様である。このように、連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させて配置するとともに、過熱部熱交換器の高さを蒸発部熱交換器より低くし、且つ、過熱部熱交換器のフィン付き伝熱管を水平に配置しているので、未蒸発の液化天然ガスが過熱部熱交換器中に滞留するのを防止するとともに、連結配管中での未蒸発の液化天然ガスの滞留をより効果的に防止することができる。
【００２５】
図８は、過熱部熱交換器の高さを蒸発部熱交換器より低く配置するとともに、連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させ、且つ、過熱部熱交換器のフィン付き伝熱管を下降勾配となるよう配置した態様である。なお、過熱部熱交換器のフィン付き伝熱管の最下段は、この部分の伝熱管内ではガス化が完了しているので勾配（傾斜）をもたせる必要はないので、水平にしてもよい。図８はこの場合を示している。
【００２６】
図８のように、過熱部熱交換器の高さを蒸発部熱交換器より低くし、連結配管を蒸発部熱交換器から過熱部熱交換器へ向けて下降傾斜させ、且つ、過熱部熱交換器のフィン付き伝熱管を下降勾配（下降傾斜）に配置することにより、連結配管から過熱部熱交換器の出口に至る全過程において、未蒸発の液化天然ガスの滞留をより効果的に防止することができる。
【００２７】
【実施例】
以下、実施例に基づき本発明をさらに詳しく説明するが、本発明が実施例に限定されないことは勿論である。比較例として図１の装置を用い、実施例として図６の装置を用いた。図９に、本実施例で用いた図６の装置の規模、寸法関係等を示している。これら装置の各所に常法に従い温度センサーを配置した。
【００２８】
蒸発部熱交換器として、ケーシング内にフィン付き伝熱管を縦方向に配置して構成し、過熱部熱交換器として、ケーシング内にフィン付き伝熱管を横方向同一面に配置し、この単位を上下に配置した。蒸発部熱交換器と過熱部熱交換器を配管（連結配管）で連結し、それぞれ、図１及び図６のように配置した。各伝熱管及び配管はアルミニウム合金製である。図６のとおり、本発明の実施例では、過熱部熱交換器の高さを蒸発部熱交換器より低くして連結配管中を流通するガスがダウンフローとなるよう過熱部熱交換器に連結している。
【００２９】
〈比較例〉
図１の装置を用いて運転した。運転条件は以下のとおりである。大気温度：約５℃。運転圧力：０．５ＭＰａ。ＬＮＧ流量：１ｔ／ｈ（定格）。運転時間：定格流量に到達後５時間。導入ＬＮＧの組成及び熱量は表１のとおりである。
【００３０】
【表 １】
上記運転条件下、蒸発、加温運転を続けたところ、蒸発部熱交換器出口温度が約−６０℃以下となると、過熱部熱交換器出口ガスの熱量変動が発生し始めた。すなわち、ＬＮＧ熱量：４４．９４ＭＪ／ｍ3Ｎ（約４５ＭＪ／ｍ3Ｎ）に対して、過熱部熱交換器出口ガスの熱量が約−２〜５ＭＪ／ｍ3Ｎの範囲で不規則に変動した。このことからして、このままの状態で運転を続けると、過熱部熱交換器出口ガスにＬＰＧを添加して熱量調整し（一例として４４．３〜４７．７ＭＪ／ｍ3Ｎの範囲）、送出される送出ガス（都市ガス）の燃焼性に悪影響を与えてしまう。
【００３２】
〈実施例〉
図６の装置を用いて運転した。運転条件は比較例と同じくした。運転を続けたところ、過熱部熱交換器出口の天然ガスの熱量に変動はなく、ほぼ一定の熱量：４４．９４ＭＪ／ｍ3Ｎ（約４５ＭＪ／ｍ3Ｎ）が維持された。このことは、このままの状態で運転を続けて、過熱部熱交換器出口ガスにＬＰＧを添加し、熱量調整して送出しても、送出ガス（都市ガス）の燃焼性に悪影響を与えることなく運転を続けることができることを示している。
【００３３】
【発明の効果】
本発明によれば、液化天然ガス用エアフィン式気化装置において、季節や昼夜を問わず製造ガスの組成変化、熱量変動を無くし、常時所望、所定品質の都市ガスを得ることができる。すなわち、未蒸発の液化天然ガスが蒸発部熱交換器より後段の配管や過熱部熱交換器の流路内に滞留することが無くなるので、液化天然ガスの蒸発、加温が安定し、製造ガスの組成変化、熱量変動を防止でき、都市ガスの品質を安定化させることができる。また、従来の過熱部熱交換器では生じる、溶接部が存在するＵベント部での低温液滞留の繰り返しが防止できるので、温度変化の繰り返しによる溶接部での繰り返し熱応力の発生がなくなり、その耐久性を向上させることができるなど各種有用な効果が得られる。
【図面の簡単な説明】
【図１】液化天然ガス用エアフィン式気化装置の概略を示す図（本発明適用前）
【図２】液化天然ガス用エアフィン式気化装置の概略を示す図（本発明適用前）
【図３】本発明の態様例を示す図
【図４】本発明の態様例を示す図
【図５】本発明の態様例を示す図
【図６】本発明の態様例を示す図
【図７】本発明の態様例を示す図
【図８】本発明の態様例を示す図
【図９】図６の装置の規模、寸法関係等を示した図（実施例）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air fin type vaporizer for liquefied natural gas (LNG).
[0002]
[Prior art]
At satellite bases (city gas production and supply bases) that handle a small amount of liquefied natural gas, air fin type vaporizers for liquefied natural gas using the atmosphere as a heat source are mainly used. This vaporizer is composed of a liquefied natural gas evaporation section and a superheating section (= heating section), and obtains heat necessary for the evaporation and overheating (= heating) of the liquefied natural gas from the atmosphere. Has the advantage that it takes little. In this vaporizer, there are two methods for supplying air, which is a heat source: a natural ventilation method and a forced ventilation method.
[0003]
FIGS. 1-2 is a figure which shows the outline of the air fin type vaporizer for liquefied natural gas by a forced ventilation system. First, in the format of FIG. 1, the heat exchanger of an evaporation part and the heat exchanger of a superheat part are arrange | positioned and comprised in a container (casing). In the evaporator heat exchanger, a plurality of heat transfer tubes (tubular heat exchangers) with fins are arranged in the vertical direction and are connected to the upper and lower header tubes, respectively. The heat transfer tube can be integrally formed with fins and tubes, for example, by extrusion. In the superheater heat exchanger, a plurality of heat transfer tubes (tubular heat exchangers) with fins are arranged in the vertical direction, and the heat transfer tubes are connected to each other at the upper and lower portions via U vent tubes.
[0004]
An air inlet is provided in the lower part of the casing, and fans for forced ventilation are arranged in the upper part of the casing corresponding to the evaporation part heat exchanger and the superheater heat exchanger, respectively. By sucking the atmosphere with a forced ventilation fan and circulating it upward in the casing, the liquefied natural gas is heated and evaporated by the evaporation section heat exchanger, and the natural gas (NG) evaporated here is exchanged by the superheated section. Heat with a vessel. The natural gas evaporated in the evaporator heat exchanger is supplied to the superheater heat exchanger through a connecting pipe.
[0005]
As shown in FIG. 1, the upper part of the evaporator heat exchanger and the upper part of the superheater heat exchanger in this vaporizer are arranged at the same height, that is, at the same level, and the pipes (connection pipes) connecting them are horizontal, that is, at the same level. Is arranged. The flow directions of liquefied natural gas and evaporative natural gas are alternately up-flow and down-flow in the evaporating section heat exchanger and up and down in the upper and lower U vent sections in the superheated section heat exchanger. ing.
[0006]
During operation, liquefied natural gas (LNG) is supplied from the lower part of the evaporator heat exchanger to each heat transfer pipe via the header pipe, heated by the atmosphere while elevating in each heat transfer pipe, and then evaporated. From the header pipe through the connecting pipe, it is supplied from the upper part of the superheater heat exchanger, heated by the superheater heat exchanger, and derived as natural gas (NG). The obtained natural gas is converted into city gas through heat quantity adjustment by adding LPG (liquefied petroleum gas) and supplied to consumers.
[0007]
Next, the format of FIG. 2 is basically the same as that of the format of FIG. 1, but here heat transfer tubes (tubular heat exchangers) arranged horizontally in several upper and lower stages as a superheater heat exchanger. 1 and using the warm air obtained by burning its own production gas, that is, natural gas, for the heating of the superheater heat exchanger. As shown in FIG. 2, the production gas is branched from the outlet conduit of the superheater heat exchanger, supplied to the burner, and burned by air. Then, the generated combustion gas is supplied to the lower part of the superheater heat exchanger to heat the superheater heat exchanger.
[0008]
[Problems to be solved by the invention]
By the way, the air fin type vaporizer for liquefied natural gas as described above is usually operated regardless of the season or day and night. When the inventors have observed the operating state in detail, when the atmospheric temperature is low, such as in winter or at dawn, the composition of the production gas obtained through the superheater heat exchanger, that is, the natural gas changes, and the calorific value fluctuates. It has been found that this adversely affects the quality of city gas produced through calorific adjustment through the addition of LPG. If the calorific value of the city gas changes, there will be a problem in terms of combustibility, and it will be necessary to stop the production of city gas, which will have an impact on consumers.
[0009]
Therefore, the present invention solves the above-mentioned problems that occur in the air fin type vaporizer for liquefied natural gas, eliminates the composition change of the production gas, that is, natural gas, regardless of the season or day and night during its operation, and changes the calorific value based on the composition change. It is an object of the present invention to provide an air fin type vaporizer for liquefied natural gas which can be supplied constantly and with desired and predetermined quality city gas.
[0010]
[Means for Solving the Problems]
The present invention relates to an air fin type vaporizer for liquefied natural gas in which the upper part of the liquefied natural gas evaporating part heat exchanger and the upper part of the superheated part heat exchanger are connected via a header pipe through a connecting pipe. An air fin type vaporizer for liquefied natural gas is provided, wherein the connecting pipe is connected to a superheater heat exchanger so as to be in a down flow.
[0011]
The present invention also relates to an air fin type vaporizer for liquefied natural gas in which the upper part of the liquefied natural gas evaporation section heat exchanger and the upper portion of the superheated section heat exchanger are connected by a connecting pipe via a header pipe. The liquefaction is characterized in that the height of the upper part of the vessel is lower than the upper part of the evaporator heat exchanger, and the connecting pipe is connected to the superheater heat exchanger so that the natural gas flowing therethrough is downflowed. An air fin type vaporizer for natural gas is provided.
[0012]
Furthermore, the present invention provides an overheated part heat exchange in an air fin type vaporizer for liquefied natural gas in which the upper part of the liquefied natural gas evaporating part heat exchanger and the upper part of the superheated part heat exchanger are connected by a connecting pipe via a header pipe. An air fin type vaporizer for liquefied natural gas, characterized in that the structure of the vessel is configured so that the natural gas flowing through it does not flow up.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The air fin type vaporizer for liquefied natural gas according to the present invention comprises, as its basic structure, a liquefied natural gas evaporation section heat exchanger and a superheat section heat exchanger, and is piped through a header pipe at the top of both heat exchangers. (Connected piping) Connected and configured. The evaporator heat exchanger is heated by the atmosphere, and the superheater heat exchanger is heated by (1) the atmosphere, (2) hot air obtained by burning its own production gas, that is, natural gas, or (3) hot water. . The liquefied natural gas evaporates in the evaporator heat exchanger, is introduced into the superheater heat exchanger through the connecting pipe, and is heated here.
[0014]
As described above, when the atmospheric temperature is low, the composition of the natural gas obtained through the superheater heat exchanger changes, resulting in a change in calorie, which may adversely affect the quality of city gas produced by adjusting the calorie. I understood. When the cause of this heat fluctuation was further observed and pursued, when the atmospheric temperature was low, when the unvaporized liquefied natural gas that flowed into the superheater heat exchanger turned from downflow to upflow in the superheater heat exchanger It has been found that it stays in the U vent part at the lower end, and when the staying amount reaches a certain amount, it is swept away by the change of fluid force and evaporates. Moreover, it has been found that the above stagnation phenomenon also occurs in the connecting pipe from the horizontally disposed evaporator heat exchanger to the superheated heat exchanger.
[0015]
That is, liquefied natural gas contains methane as a main component, but contains heavy hydrocarbon gas such as propane, butane, and pentane. When this is evaporated and heated, when the atmospheric temperature is low as described above, the composition change occurs in the natural gas obtained through the evaporating part heat exchanger and the superheated part heat exchanger in the horizontal connection pipe or This is because the non-evaporated heavy hydrocarbon gas stays in the U vent at the lower end of the superheater heat exchanger.
[0016]
Therefore, in the present invention, in order to eliminate the above stay, the connecting pipe is arranged in the down flow. As a way of arranging the connecting pipe in the down flow, (1) the superheater heat exchanger is placed lower than the evaporator heat exchanger, that is, the upper part of the superheater heat exchanger is lower than the upper part of the evaporator heat exchanger. (2) The connecting pipe is disposed so as to be inclined downward from the evaporator heat exchanger to the superheater heat exchanger, (3) The above (1) and (2) are arranged together, and the like. Can be done. This prevents un-evaporated liquefied natural gas from the evaporating section heat exchanger from staying in the connecting pipe and the superheated section heat exchanger, and avoids changes in the composition of the natural gas obtained via the superheated section heat exchanger. Thus, fluctuations in the amount of heat can be prevented.
[0017]
Moreover, in this invention, in order to eliminate the above stay, the structure of the superheater heat exchanger itself is made into a structure which does not become an upflow. To make the structure of the superheater heat exchanger itself non-upflow, (1) arrange the heat exchanger tubes of the superheater heat exchanger horizontally, (2) down the heat exchanger tubes of the superheater heat exchanger It can be performed in such a manner that it is arranged so as to be a flow (that is, a flow of natural gas flowing through the heat transfer tube is a downward flow). This prevents unevaporated liquefied natural gas from staying in the superheater heat exchanger, avoids changes in the composition of natural gas obtained through the superheater heat exchanger, and prevents fluctuations in the amount of heat. it can.
[0018]
3-8 is a figure which shows the example of an aspect of this invention. FIG. 3 shows a mode in which the present invention is applied to the vaporizer corresponding to FIG. As shown in FIG. 3, the height of the superheater heat exchanger is lower than that of the evaporator heat exchanger, that is, the upper part of the superheater heat exchanger is lower than the upper part of the evaporator heat exchanger, and as the superheater heat exchanger, A plurality of finned heat transfer tubes connected to the upper and lower header tubes are arranged in the vertical direction so that the natural gas from the connection piping flows only downward.
[0019]
FIG. 4 is an embodiment in which a partition wall is provided between the evaporator heat exchanger and the superheater heat exchanger arranged in the casing in the embodiment of FIG. 3 to 4, the natural gas from the connecting pipe is configured to flow only in the downward direction in the superheater heat exchanger, so that the unevaporated liquefied natural gas is in the superheater heat exchanger. And prevent the unheated liquefied natural gas from staying in the connection pipe by arranging the superheater heat exchanger lower than the evaporating part heat exchanger. Can do.
[0020]
As shown in FIG. 1, conventionally, each heat transfer tube is connected with a U vent pipe at the top and bottom, and the U vent pipe is connected to the heat transfer tube by welding. For this reason, if the low temperature liquid stays repeatedly in the U vent where the weld is present, repeated thermal stresses are generated in the weld due to repeated temperature changes, which impairs the durability of the superheater heat exchanger. However, in the present invention, the retention of the low temperature liquid in the heat transfer tube is prevented, so that the durability can be improved.
[0021]
FIG. 5 is a mode in which, in addition to the configuration of FIG. 3, the connecting pipe is inclined downward from the evaporator heat exchanger to the superheater heat exchanger. As shown in FIG. 5, the connecting pipe itself is inclined downward so that the gas from the evaporator heat exchanger becomes a downflow. This prevents unevaporated liquefied natural gas from staying in the superheater heat exchanger and prevents unevaporated liquefied natural gas from staying in the connecting pipe, as in FIGS. It can be effectively prevented.
[0022]
FIG. 6 is the same as the vaporizer of FIG. 2 in that warm air obtained by burning its own production gas is used to heat the superheater heat exchanger. As shown in FIG. 6, the heat exchanger tube with fins of the superheater heat exchanger has a structure in which the height of the superheater heat exchanger is lower than that of the evaporator heat exchanger and the gas does not flow up in the superheater heat exchanger. Are arranged horizontally in multiple stages. Since the height of the superheater heat exchanger is lower than that of the evaporator heat exchanger, and the finned heat transfer tubes of the superheater heat exchanger are arranged horizontally, the evacuated liquefied natural gas in the connecting pipe Stagnation of the liquefied natural gas which has not been evaporated in the superheater heat exchanger can be prevented.
[0023]
In addition, it can replace with using warm air as mentioned above as a heating source of a superheater heat exchanger, and can also use warm water. In this case, as the superheater heat exchanger, a known gas-liquid heat exchanger such as a form in which hot water is circulated on the outer surface of the heat transfer tube through which gas circulates can be used, and as a heat source for generating hot water, In addition to the combustion gas obtained by burning the production gas, other heat sources such as city gas combustion gas may be used.
[0024]
FIG. 7 is a mode in which, in addition to the configuration of FIG. 6, the connecting pipe is disposed so as to be inclined downward from the evaporator heat exchanger to the superheater heat exchanger. In this way, the connecting pipe is disposed so as to be inclined downward from the evaporator heat exchanger to the superheater heat exchanger, the height of the superheater heat exchanger is lower than that of the evaporator heat exchanger, and the superheater is heated. Since the heat transfer tubes with fins of the partial heat exchanger are arranged horizontally, it is possible to prevent unvaporized liquefied natural gas from staying in the superheated heat exchanger and Gas retention can be prevented more effectively.
[0025]
FIG. 8 shows that the height of the superheater heat exchanger is lower than that of the evaporator heat exchanger, the connecting pipe is inclined downward from the evaporator heat exchanger to the superheater heat exchanger, and the superheater heat is It is the aspect which has arrange | positioned the heat exchanger tube with a fin of an exchanger so that it may become a downward gradient. Note that the lowermost stage of the finned heat transfer tube of the superheater heat exchanger may be horizontal because it is not necessary to provide a gradient (inclination) since gasification is completed in this portion of the heat transfer tube. FIG. 8 shows this case.
[0026]
As shown in FIG. 8, the height of the superheater heat exchanger is made lower than that of the evaporator heat exchanger, the connecting pipe is inclined downward from the evaporator heat exchanger to the superheater heat exchanger, and the superheater heat is By arranging the finned heat transfer tubes of the exchanger in a descending gradient (declining gradient), it is possible to more effectively prevent the accumulation of unevaporated liquefied natural gas in the entire process from the connection pipe to the outlet of the superheater heat exchanger. can do.
[0027]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, of course, this invention is not limited to an Example. The apparatus of FIG. 1 was used as a comparative example, and the apparatus of FIG. 6 was used as an example. FIG. 9 shows the scale, dimensional relationship, etc. of the apparatus of FIG. 6 used in this embodiment. Temperature sensors were arranged in various places in these apparatuses according to a conventional method.
[0028]
As the evaporator heat exchanger, the finned heat transfer tubes are arranged in the vertical direction in the casing, and as the superheater heat exchanger, the finned heat transfer tubes are arranged in the horizontal direction on the same plane. Arranged vertically. The evaporator heat exchanger and the superheater heat exchanger were connected by pipes (connecting pipes) and arranged as shown in FIGS. 1 and 6, respectively. Each heat transfer tube and pipe are made of an aluminum alloy. As shown in FIG. 6, in the embodiment of the present invention, the height of the superheater heat exchanger is made lower than that of the evaporator heat exchanger, and the gas flowing through the connecting pipe is connected to the superheater heat exchanger so as to flow down. is doing.
[0029]
<Comparative example>
Operation was performed using the apparatus of FIG. The operating conditions are as follows. Atmospheric temperature: about 5 ° C. Operating pressure: 0.5 MPa. LNG flow rate: 1 t / h (rated). Operating time: 5 hours after reaching the rated flow rate. The composition and heat quantity of the introduced LNG are as shown in Table 1.
[0030]
[Table 1]
When the evaporation and warming operation was continued under the above operating conditions, when the evaporating section heat exchanger outlet temperature became about −60 ° C. or less, the heat amount fluctuation of the superheated section heat exchanger outlet gas began to occur. That is, with respect to LNG heat quantity: 44.94 MJ / m 3 N (about 45 MJ / m 3 N), the heat quantity of the superheater heat exchanger outlet gas fluctuates irregularly in a range of about −2 to 5 MJ / m 3 N. did. Therefore, if the operation is continued as it is, the amount of heat is adjusted by adding LPG to the outlet gas of the superheater heat exchanger (as an example, in the range of 44.3 to 47.7 MJ / m 3 N), and sent out. This will adversely affect the combustibility of the delivered gas (city gas).
[0032]
<Example>
Operation was performed using the apparatus shown in FIG. The operating conditions were the same as in the comparative example. Was continued operation, no change to the amount of heat of natural gas superheating unit heat exchanger outlet, a substantially constant amount of heat: 44.94MJ / m 3 N (about 45MJ / m 3 N) was maintained. This means that even if the operation is continued as it is, LPG is added to the superheater heat exchanger outlet gas, and the amount of heat is adjusted and sent without adversely affecting the combustibility of the delivery gas (city gas). Indicates that you can continue driving.
[0033]
【The invention's effect】
According to the present invention, in an air fin type vaporizer for liquefied natural gas, it is possible to always obtain desired and predetermined quality city gas by eliminating the composition change and calorie fluctuation of the production gas regardless of the season or day and night. In other words, unevaporated liquefied natural gas does not stay in the piping downstream of the evaporation section heat exchanger or the flow path of the superheated section heat exchanger, so that the evaporation and heating of the liquefied natural gas is stable, and the production gas It is possible to prevent changes in the composition and fluctuations in the amount of heat and stabilize the quality of city gas. In addition, since it is possible to prevent the low temperature liquid staying in the U vent part where the weld exists, which occurs in the conventional superheated part heat exchanger, the occurrence of repeated thermal stress in the weld due to repeated temperature changes is eliminated. Various useful effects such as improvement of durability can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an air fin type vaporizer for liquefied natural gas (before application of the present invention)
FIG. 2 is a schematic view of an air fin type vaporizer for liquefied natural gas (before application of the present invention)
FIG. 3 is a diagram showing an example of an embodiment of the present invention. FIG. 4 is a diagram showing an example of an embodiment of the present invention. FIG. 5 is a diagram showing an example of an embodiment of the present invention. 7 is a diagram showing an example of an embodiment of the present invention. FIG. 8 is a diagram showing an example of an embodiment of the present invention. FIG. 9 is a diagram showing the scale, dimensional relationship, etc. of the apparatus of FIG.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001267999A JP4684497B2 (en) | 2001-09-04 | 2001-09-04 | Air fin type vaporizer for liquefied natural gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001267999A JP4684497B2 (en) | 2001-09-04 | 2001-09-04 | Air fin type vaporizer for liquefied natural gas |
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| JP2003074793A JP2003074793A (en) | 2003-03-12 |
| JP4684497B2 true JP4684497B2 (en) | 2011-05-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP2001267999A Expired - Fee Related JP4684497B2 (en) | 2001-09-04 | 2001-09-04 | Air fin type vaporizer for liquefied natural gas |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US8069677B2 (en) * | 2006-03-15 | 2011-12-06 | Woodside Energy Ltd. | Regasification of LNG using ambient air and supplemental heat |
| US20070214805A1 (en) | 2006-03-15 | 2007-09-20 | Macmillan Adrian Armstrong | Onboard Regasification of LNG Using Ambient Air |
| CN101419026A (en) * | 2008-10-17 | 2009-04-29 | 俞军 | Improved air-bathing gasifier |
| AU2012216352B2 (en) | 2012-08-22 | 2015-02-12 | Woodside Energy Technologies Pty Ltd | Modular LNG production facility |
| JP6774905B2 (en) | 2017-04-19 | 2020-10-28 | レール・リキード−ソシエテ・アノニム・プール・レテュード・エ・レクスプロワタシオン・デ・プロセデ・ジョルジュ・クロード | Liquefied gas supply backup system and liquefied gas reserve supply method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55142199A (en) * | 1979-04-20 | 1980-11-06 | Mitsui Eng & Shipbuild Co Ltd | Device for evaporating liquefied gas by air heat |
| JPS6234297U (en) * | 1985-08-16 | 1987-02-28 | ||
| JPH0256560B2 (en) * | 1987-09-11 | 1990-11-30 | Tokyo Gas Co Ltd | |
| JPH09165588A (en) * | 1995-12-18 | 1997-06-24 | Showa Alum Corp | White smoke-preventing device of liquid gas evaporator |
| JPH09303696A (en) * | 1996-05-10 | 1997-11-28 | Kobe Steel Ltd | Low-temperature liquefied gas gasifying device |
| JPH10196894A (en) * | 1996-12-27 | 1998-07-31 | Tokyo Gas Co Ltd | Heat quantity controller for liquefied natural gas |
-
2001
- 2001-09-04 JP JP2001267999A patent/JP4684497B2/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55142199A (en) * | 1979-04-20 | 1980-11-06 | Mitsui Eng & Shipbuild Co Ltd | Device for evaporating liquefied gas by air heat |
| JPS6234297U (en) * | 1985-08-16 | 1987-02-28 | ||
| JPH0256560B2 (en) * | 1987-09-11 | 1990-11-30 | Tokyo Gas Co Ltd | |
| JPH09165588A (en) * | 1995-12-18 | 1997-06-24 | Showa Alum Corp | White smoke-preventing device of liquid gas evaporator |
| JPH09303696A (en) * | 1996-05-10 | 1997-11-28 | Kobe Steel Ltd | Low-temperature liquefied gas gasifying device |
| JPH10196894A (en) * | 1996-12-27 | 1998-07-31 | Tokyo Gas Co Ltd | Heat quantity controller for liquefied natural gas |
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