JP5782213B2 - Corrosion prevention method for multi-tube reactors - Google Patents

Corrosion prevention method for multi-tube reactors Download PDF

Info

Publication number
JP5782213B2
JP5782213B2 JP2008027667A JP2008027667A JP5782213B2 JP 5782213 B2 JP5782213 B2 JP 5782213B2 JP 2008027667 A JP2008027667 A JP 2008027667A JP 2008027667 A JP2008027667 A JP 2008027667A JP 5782213 B2 JP5782213 B2 JP 5782213B2
Authority
JP
Japan
Prior art keywords
gas
shell
heat medium
volume
reaction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2008027667A
Other languages
Japanese (ja)
Other versions
JP2009183887A (en
Inventor
友基 福井
友基 福井
宣生 百冨
宣生 百冨
正範 新田
正範 新田
俊裕 佐藤
俊裕 佐藤
大輔 富川
大輔 富川
黒田　徹
徹 黒田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Chemical Corp
Mitsubishi Rayon Co Ltd
Original Assignee
Mitsubishi Chemical Corp
Mitsubishi Rayon Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Chemical Corp, Mitsubishi Rayon Co Ltd filed Critical Mitsubishi Chemical Corp
Priority to JP2008027667A priority Critical patent/JP5782213B2/en
Publication of JP2009183887A publication Critical patent/JP2009183887A/en
Application granted granted Critical
Publication of JP5782213B2 publication Critical patent/JP5782213B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Physical Or Chemical Processes And Apparatus (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Description

本発明は、多管式反応器の腐食防止方法に関する。   The present invention relates to a corrosion prevention method for a multitubular reactor.

（メタ）アクロレイン、（メタ）アクリル酸等は、触媒が充填された複数の反応管をシェル内に配置した多管式反応器を用いた気相接触酸化反応によって製造される。
該多管式反応器においては、反応管内の温度を調節するために、多管式反応器と熱媒ドラムとの間で循環する熱媒が、シェル内の反応管外に導入される（たとえば、特許文献１）。そして、（メタ）アクロレイン、（メタ）アクリル酸等の製造を終了した際には、熱媒の循環も停止され、熱媒はシェル内から抜き取られ、シェル内には代わりに空気が流れ込む。 (Meth) acrolein, (meth) acrylic acid, and the like are produced by a gas phase catalytic oxidation reaction using a multitubular reactor in which a plurality of reaction tubes filled with a catalyst are arranged in a shell.
In the multitubular reactor, in order to adjust the temperature in the reaction tube, a heat medium circulating between the multitubular reactor and the heat medium drum is introduced outside the reaction tube in the shell (for example, Patent Document 1). When the production of (meth) acrolein, (meth) acrylic acid or the like is finished, the circulation of the heat medium is also stopped, the heat medium is extracted from the shell, and air flows into the shell instead.

しかし、シェル内から熱媒を完全に抜き取ることは困難であり、シェル内の反応管外に熱媒が残留する。そして、シェル内に残留する熱媒がシェル内の空気中の水分を吸収するため、該水分によって炭素鋼（シェルの内壁および反応管の外壁。）が腐食する場合がある。特に、熱媒として溶融塩（亜硝酸ナトリウム、硝酸ナトリウムおよび硝酸カリウム。）を用いた場合、溶融塩が吸湿しやすいため、炭素鋼の腐食が起こりやすい。
特開２００１−３１０１２３号公報 However, it is difficult to completely extract the heat medium from the shell, and the heat medium remains outside the reaction tube in the shell. And since the heat medium which remains in a shell absorbs the water | moisture content in the air in a shell, carbon steel (the inner wall of a shell and the outer wall of a reaction tube) may corrode by this water | moisture content. In particular, when a molten salt (sodium nitrite, sodium nitrate, and potassium nitrate) is used as a heat medium, the molten salt tends to absorb moisture, and therefore, corrosion of carbon steel is likely to occur.
JP 2001-310123 A

本発明は、シェル内の反応管外に導入される熱媒の少なくとも一部を抜いた状態におけるシェル内の腐食を抑えることができる多管式反応器の腐食防止方法を提供する。   The present invention provides a corrosion prevention method for a multi-tubular reactor that can suppress corrosion in the shell in a state in which at least a part of the heat medium introduced outside the reaction tube in the shell is removed.

本発明の多管式反応器の腐食防止方法は、複数の反応管をシェル内に配置した多管式反応器の腐食防止方法であって、前記シェル内の前記反応管外に導入される熱媒である亜硝酸ナトリウム、硝酸カリウムおよび硝酸ナトリウムを含む溶融塩の少なくとも一部を、前記シェル内から抜いた際に、前記シェル内に形成される気相部の水分が０．５〜１体積％、かつ前記気相部の酸素濃度が４〜５体積％になるまで前記シェル内に置換ガスを通気し、前記気相部の水分を０．５〜１体積％、かつ前記気相部の酸素濃度を４〜５体積％に保持することを特徴とする。 The multi-tube reactor corrosion prevention method of the present invention is a multi-tube reactor corrosion prevention method in which a plurality of reaction tubes are arranged in a shell, and the heat introduced outside the reaction tube in the shell. When at least part of the molten salt containing sodium nitrite, potassium nitrate, and sodium nitrate, which is a medium, is extracted from the shell, the moisture in the gas phase formed in the shell is 0.5 to 1 % by volume . In addition, a replacement gas is passed through the shell until the oxygen concentration in the gas phase becomes 4 to 5 % by volume , the moisture in the gas phase becomes 0.5 to 1 % by volume , and oxygen in the gas phase The concentration is maintained at 4 to 5 % by volume.

前記置換ガスは、水分が０．５体積％以下のガスであることが好ましい。 Before Symbol replacement gas is preferably water is 0.5% by volume or less of gas.

本発明の多管式反応器の腐食防止方法によれば、シェル内の反応管外に導入される熱媒の少なくとも一部を抜いた状態におけるシェル内の腐食を抑えることができる。   According to the corrosion prevention method for a multitubular reactor of the present invention, corrosion in the shell in a state where at least a part of the heat medium introduced outside the reaction tube in the shell is removed can be suppressed.

本明細書においては、（メタ）アクロレインとは、アクロレインまたはメタクロレインを意味し、（メタ）アクリル酸は、アクリル酸またはメタクリル酸を意味する。   In the present specification, (meth) acrolein means acrolein or methacrolein, and (meth) acrylic acid means acrylic acid or methacrylic acid.

図１は、（メタ）アクロレイン、（メタ）アクリル酸等の製造装置の一例を示す概略図である。製造装置１は、多管式反応器１０と、熱媒を貯留する熱媒ドラム１２と、熱媒ドラム１２に隣接して設けられた熱媒加熱炉（図示略）と、熱媒から熱を回収する熱交換器１４と、多管式反応器１０との間で熱媒を循環させるポンプタンク１６と、熱媒ドラム１２の熱媒を、熱交換器１４を経てポンプタンク１６に供給する熱媒供給流路２０と、多管式反応器１０とポンプタンク１６との間で熱媒を循環させる熱媒循環流路２２と、ポンプタンク１６でオーバーフローした熱媒を熱媒ドラム１２に返送する熱媒返送流路２４と、熱媒循環流路２２の最も低い位置から分岐し、多管式反応器１０とポンプタンク１６との間で循環する熱媒を熱媒ドラム１２に回収する熱媒回収流路２６と、ポンプタンク１６に空気を導入する空気導入流路２８と、熱媒回収流路２６の途中に設けられた弁３０と、空気導入流路２８の途中に設けられた弁３２とを具備する。   FIG. 1 is a schematic diagram illustrating an example of a production apparatus for (meth) acrolein, (meth) acrylic acid, and the like. The production apparatus 1 includes a multi-tubular reactor 10, a heat medium drum 12 for storing a heat medium, a heat medium heating furnace (not shown) provided adjacent to the heat medium drum 12, and heat from the heat medium. Heat supplied from the heat exchanger 14 to be recovered and the pump tank 16 for circulating the heat medium between the multi-tubular reactor 10 and the heat medium of the heat medium drum 12 to the pump tank 16 via the heat exchanger 14 The medium supply flow path 20, the heat medium circulation path 22 for circulating the heat medium between the multitubular reactor 10 and the pump tank 16, and the heat medium overflowed in the pump tank 16 are returned to the heat medium drum 12. A heat medium that branches from the lowest position of the heat medium return flow path 24 and the heat medium circulation flow path 22 and circulates between the multitubular reactor 10 and the pump tank 16 in the heat medium drum 12. A recovery passageway 26, an air introduction passageway 28 for introducing air into the pump tank 16, It includes a valve 30 provided in the middle of the medium recovery path 26, a valve 32 provided in the middle of the air introduction flow path 28.

多管式反応器１０は、図２に示すように、触媒が充填された複数の反応管４０と、反応管４０を収納するシェル４２と、反応管４０の入口側に設けられた下部チャンネル４４と、反応管４０の出口側に設けられた上部チャンネル４６と、反応管４０の両端を束ねた状態でシェル４２に固定されることによって、シェル４２と下部チャンネル４４、およびシェル４２と上部チャンネル４６とを仕切る管板４８とを具備する。シェル４２の周壁には、熱媒導入口５０および熱媒排出口５２が設けられ、下部チャンネル４４には原料ガス導入口５４が設けられ、上部チャンネル４６には反応ガス排出口５６が設けられている。   As shown in FIG. 2, the multitubular reactor 10 includes a plurality of reaction tubes 40 filled with a catalyst, a shell 42 that houses the reaction tubes 40, and a lower channel 44 provided on the inlet side of the reaction tubes 40. And the upper channel 46 provided on the outlet side of the reaction tube 40, and the shell 42 and the lower channel 44, and the shell 42 and the upper channel 46 by being fixed to the shell 42 in a state where both ends of the reaction tube 40 are bundled. And a tube plate 48 for partitioning. A heat medium inlet 50 and a heat medium outlet 52 are provided on the peripheral wall of the shell 42, a raw material gas inlet 54 is provided in the lower channel 44, and a reaction gas outlet 56 is provided in the upper channel 46. Yes.

熱媒ドラム１２には、熱媒を送り出すポンプ３４と、装置の運転を停止している間の熱媒の固化を防止するための蒸気コイル３６とが設けられている。
熱交換器１４は、多管式反応器１０の反応熱で温度が上昇した熱媒から熱を回収し、上昇した分だけ熱媒の温度を下げるものである。熱媒循環流路２２および熱媒返送流路２４は、多管式反応器１０の反応熱で温度が上昇した熱媒がポンプタンク１６において優先的にオーバーフローし、熱媒ドラム１２に返送されるように配設される。 The heat medium drum 12 is provided with a pump 34 for sending out the heat medium and a steam coil 36 for preventing the heat medium from solidifying while the operation of the apparatus is stopped.
The heat exchanger 14 recovers heat from the heat medium whose temperature has risen due to the reaction heat of the multitubular reactor 10, and lowers the temperature of the heat medium by the increased amount. In the heat medium circulation flow path 22 and the heat medium return flow path 24, the heat medium whose temperature has risen due to the reaction heat of the multitubular reactor 10 overflows preferentially in the pump tank 16 and is returned to the heat medium drum 12. It is arranged as follows.

熱媒としては、溶融塩（いわゆるナイター。）、溶融金属、有機熱媒体等が挙げられ、熱安定性、取扱性等の点から、ナイターが好ましい。
ナイターとは、亜硝酸ナトリウム、硝酸カリウム、硝酸ナトリウム等を含んだ高温用熱媒体であり、通常、亜硝酸ナトリウム４０質量％、硝酸ナトリウム７質量％および硝酸カリウム５３質量％の混合物が用いられる。 Examples of the heat medium include molten salt (so-called nighter), molten metal, organic heat medium, and the like, and niter is preferable from the viewpoints of thermal stability, handleability, and the like.
Nighter is a heat medium for high temperature containing sodium nitrite, potassium nitrate, sodium nitrate, etc., and a mixture of 40% by mass of sodium nitrite, 7% by mass of sodium nitrate and 53% by mass of potassium nitrate is usually used.

つぎに、製造装置１を用いた（メタ）アクロレインの製造、および（メタ）アクリル酸の製造について説明する。   Next, production of (meth) acrolein and production of (meth) acrylic acid using the production apparatus 1 will be described.

（メタ）アクロレインの製造：
多管式反応器１０の反応管４０内に触媒を充填する。
熱媒ドラム１２内の熱媒を熱媒加熱炉との間で循環させ、所定の温度まで加熱する。
熱媒ドラム１２内の熱媒をポンプタンク１６に連続的に供給する。
該熱媒をポンプタンク１６と多管式反応器１０との間で循環させることによって、多管式反応器１０のシェル４２内に熱媒を導入し、反応管４０内を所定の反応温度に昇温する。 Production of (meth) acrolein:
The catalyst is filled in the reaction tube 40 of the multitubular reactor 10.
The heat medium in the heat medium drum 12 is circulated between the heat medium heating furnace and heated to a predetermined temperature.
The heat medium in the heat medium drum 12 is continuously supplied to the pump tank 16.
By circulating the heat medium between the pump tank 16 and the multitubular reactor 10, the heat medium is introduced into the shell 42 of the multitubular reactor 10, and the reaction tube 40 is brought to a predetermined reaction temperature. Raise the temperature.

多管式反応器１０の下部チャンネル４４内に原料ガス導入口５４から原料ガスを供給し、該原料ガスを所定の空間速度にて反応管４０内を通過させる。
反応管４０から排出される（メタ）アクロレインを含む反応ガスは、上部チャンネル４６内を通って反応ガス排出口５６から排出される。
原料ガスの反応によって発生する反応熱は、シェル４２内の熱媒にて回収する。 A raw material gas is supplied from a raw material gas inlet 54 into the lower channel 44 of the multitubular reactor 10, and the raw material gas is passed through the reaction tube 40 at a predetermined space velocity.
The reaction gas containing (meth) acrolein discharged from the reaction tube 40 passes through the upper channel 46 and is discharged from the reaction gas discharge port 56.
The reaction heat generated by the reaction of the raw material gas is recovered by the heat medium in the shell 42.

多管式反応器１０の反応熱で温度が上昇し、ポンプタンク１６に返送された熱媒を、ポンプタンク１６において優先的にオーバーフローさせ、熱媒ドラム１２に返送する。
熱媒ドラム１２内の熱媒の温度が上昇するため、熱媒ドラム１２内の熱媒をポンプタンク１６に供給する際に、熱交換器１４にて熱媒から熱を回収し、多管式反応器１０の反応熱で温度が上昇した分だけ熱媒の温度を下げる。 The temperature rises due to the reaction heat of the multi-tubular reactor 10, and the heat medium returned to the pump tank 16 is preferentially overflowed in the pump tank 16 and returned to the heat medium drum 12.
Since the temperature of the heat medium in the heat medium drum 12 rises, when the heat medium in the heat medium drum 12 is supplied to the pump tank 16, heat is recovered from the heat medium by the heat exchanger 14, and a multitubular type The temperature of the heating medium is lowered by the amount that the temperature has increased due to the reaction heat of the reactor 10.

触媒としては、モリブデン、ビスマスおよび鉄を含む多元系酸化物触媒粒子等が挙げられる。
原料ガスとしては、イソブチレン、ｔ−ブタノールおよびメチル−ｔ−ブチルエーテルからなる群から選ばれる１種以上のガスの１〜２０体積％、分子状酸素の１〜２０体積％、水蒸気の０〜４０体積％、および不活性ガス（窒素、炭酸ガス等。）を含む混合ガスが挙げられる。 Examples of the catalyst include multi-component oxide catalyst particles containing molybdenum, bismuth and iron.
The source gas is 1 to 20% by volume of one or more gases selected from the group consisting of isobutylene, t-butanol and methyl-t-butyl ether, 1 to 20% by volume of molecular oxygen, and 0 to 40% by volume of water vapor. %, And a mixed gas containing an inert gas (nitrogen, carbon dioxide, etc.).

反応温度は、通常、３００〜４５０℃である。
空間速度としては、５００〜３０００ｈｒ−１が好ましい。
熱媒の温度は、通常、熱交換器１４の出口において、３００〜４５０℃である。 The reaction temperature is usually 300 to 450 ° C.
As the space velocity, 500 to 3000 hr −1 is preferable.
The temperature of the heat medium is usually 300 to 450 ° C. at the outlet of the heat exchanger 14.

（メタ）アクリル酸の製造：
触媒、原料ガス、反応温度、熱媒の温度を変更する以外は、（メタ）アクロレインの製造と同様にして（メタ）アクリル酸の製造を行う。 Production of (meth) acrylic acid:
(Meth) acrylic acid is produced in the same manner as in the production of (meth) acrolein, except that the catalyst, raw material gas, reaction temperature, and temperature of the heating medium are changed.

触媒としては、リンモリブデン酸系へテロポリ酸またはその金属塩からなる触媒粒子等が挙げられる。
原料ガスとしては、（メタ）アクロレインの１〜２０体積％、分子状酸素の１〜２０体積％、水蒸気の３〜４０体積％、不活性ガス（窒素、炭酸ガス等。）を含む混合ガスが挙げられる。
反応温度は、通常、２００〜４００℃である。
熱媒の温度は、通常、熱交換器１４の出口において、２００〜４００℃である。 Examples of the catalyst include catalyst particles made of a phosphomolybdic acid-based heteropoly acid or a metal salt thereof.
As the source gas, a mixed gas containing 1 to 20% by volume of (meth) acrolein, 1 to 20% by volume of molecular oxygen, 3 to 40% by volume of water vapor, and inert gas (nitrogen, carbon dioxide, etc.). Can be mentioned.
The reaction temperature is usually 200 to 400 ° C.
The temperature of the heat medium is usually 200 to 400 ° C. at the outlet of the heat exchanger 14.

つぎに、製造装置１の運転停止および多管式反応器１０の腐食防止方法について説明する。   Next, a method for stopping the operation of the production apparatus 1 and a method for preventing corrosion of the multitubular reactor 10 will be described.

多管式反応器１０への原料ガスの供給を停止する。
熱媒ドラム１２内の熱媒のポンプタンク１６への供給、およびポンプタンク１６と多管式反応器１０との間での熱媒の循環を停止する。 The supply of the raw material gas to the multitubular reactor 10 is stopped.
Supply of the heat medium in the heat medium drum 12 to the pump tank 16 and circulation of the heat medium between the pump tank 16 and the multitubular reactor 10 are stopped.

空気導入流路２８の弁３２および熱媒回収流路２６の弁３０を開き、ポンプタンク１６、多管式反応器１０および熱媒循環流路２２内の熱媒を、重力によって熱媒ドラム１２に自然落下させる。
弁３０および弁３２を閉じた後、２本の熱媒循環流路２２における配管接合部分を、それぞれ一箇所ずつ切り離し、図３に示すように、多管式反応器１０のシェル４２内へ置換ガスを導入するガス導入口６０、およびシェル４２内の空気および置換ガスを排出するガス排出口６２を形成する。 The valve 32 of the air introduction flow path 28 and the valve 30 of the heat medium recovery flow path 26 are opened, and the heat medium in the pump tank 16, the multi-tubular reactor 10, and the heat medium circulation flow path 22 is heated by the heat medium drum 12 by gravity. Let it fall naturally.
After the valve 30 and the valve 32 are closed, the pipe joints in the two heat medium circulation passages 22 are cut out one by one and replaced into the shell 42 of the multitubular reactor 10 as shown in FIG. A gas inlet 60 for introducing gas and a gas outlet 62 for discharging air and replacement gas in the shell 42 are formed.

ガス導入口６０からシェル４２内の反応管４０外に置換ガスを導入し、シェル４２内の反応管４０外の気相部に存在する空気、さらには置換ガスの一部をガス排出口６２から排出する。
シェル４２内の気相部の水分が所定の濃度以下になるまでシェル４２内に置換ガスを通気した後、ガス導入口６０およびガス排出口６２に閉止板を取り付け、シェル４２内の気相部を外気から遮断し、気相部の水分を所定の濃度以下に保持する。 A replacement gas is introduced from the gas inlet 60 to the outside of the reaction tube 40 in the shell 42, and air existing in the gas phase portion outside the reaction tube 40 in the shell 42 and a part of the replacement gas are further removed from the gas outlet 62. Discharge.
After the replacement gas is passed through the shell 42 until the moisture in the gas phase portion in the shell 42 becomes a predetermined concentration or less, a closing plate is attached to the gas inlet 60 and the gas outlet 62, and the gas phase portion in the shell 42 is attached. Is shielded from the outside air, and the moisture in the gas phase is kept below a predetermined concentration.

置換ガスとしては、水分が０．５体積％以下のガスが好ましい。置換ガスとしては、例えば、不活性ガス（窒素ガス、希ガス、炭酸ガス等。）、乾燥空気等が挙げられ、窒素ガスが好ましい。   As the replacement gas, a gas having a water content of 0.5% by volume or less is preferable. Examples of the replacement gas include inert gas (nitrogen gas, rare gas, carbon dioxide gas, etc.), dry air, and the like, and nitrogen gas is preferable.

シェル４２内への置換ガスの通気は、シェル４２内の気相部の水分が１体積％以下になるまで行い、気相部の水分を１体積％以下に保持することが好ましい。気相部の水分が１体積％以下であれば、シェル４２内の腐食を充分に抑えることができる。
気相部の水分は、置換ガスの通気の間、ガス排出口６２から排出されるガスの水分を測定することによって確認できる。ガス排出口６２から排出されるガスの水分は、カールフィッシャー水分計を用いて測定できる。 The replacement gas is preferably vented into the shell 42 until the moisture in the gas phase portion in the shell 42 becomes 1% by volume or less, and the moisture in the gas phase portion is preferably kept at 1% by volume or less. If the moisture in the gas phase is 1% by volume or less, corrosion in the shell 42 can be sufficiently suppressed.
The moisture in the gas phase can be confirmed by measuring the moisture of the gas discharged from the gas outlet 62 during the replacement gas flow. The moisture of the gas discharged from the gas discharge port 62 can be measured using a Karl Fischer moisture meter.

シェル４２内への置換ガスの通気は、シェル４２内の気相部の酸素濃度が５体積％以下になるまで行い、気相部の酸素濃度を５体積％以下に保持することが好ましい。シェル４２内の気相部の酸素濃度が５体積％以下であれば、シェル４２内の腐食（酸化）をさらに抑えることができる。
気相部の酸素濃度は、置換ガスの通気の間、ガス排出口６２から排出されるガスの酸素濃度を測定することによって確認できる。ガス排出口６２から排出されるガスの酸素濃度は、酸素濃度計を用いて測定できる。 The replacement gas is preferably vented into the shell 42 until the oxygen concentration in the gas phase portion in the shell 42 is 5% by volume or less, and the oxygen concentration in the gas phase portion is preferably maintained at 5% by volume or less. If the oxygen concentration in the gas phase portion in the shell 42 is 5% by volume or less, corrosion (oxidation) in the shell 42 can be further suppressed.
The oxygen concentration in the gas phase can be confirmed by measuring the oxygen concentration of the gas discharged from the gas discharge port 62 during the replacement gas flow. The oxygen concentration of the gas discharged from the gas discharge port 62 can be measured using an oxygen concentration meter.

以上説明した多管式反応器１０の腐食防止方法にあっては、シェル４２内の反応管４０外に導入される熱媒をシェル４２内から抜いた際に、シェル４２内に形成される気相部の一部を置換ガスで置換するため、シェル４２内の気相部の水分を低減できる。そのため、シェル４２内に残留する熱媒がシェル４２内の気相部の水分を吸収することによって発生するシェル４２の内壁および反応管４０の外壁の腐食が抑えられる。   In the corrosion prevention method for the multi-tubular reactor 10 described above, the gas formed in the shell 42 when the heat medium introduced to the outside of the reaction tube 40 in the shell 42 is removed from the shell 42. Since a part of the phase part is replaced with the replacement gas, moisture in the gas phase part in the shell 42 can be reduced. Therefore, corrosion of the inner wall of the shell 42 and the outer wall of the reaction tube 40 generated by the heat medium remaining in the shell 42 absorbing moisture in the gas phase portion in the shell 42 is suppressed.

なお、本発明の多管式反応器の腐食防止方法は、上述の方法に限定はされない。例えば、置換ガスを、ガス排出口６２から導入し、ガス導入口６０から排出してもよい。また、多管式反応器１０から熱媒循環流路２２の配管を切り離し、多管式反応器１０のシェル４２の熱媒導入口５０および熱媒排出口５２を、ガス導入口６０およびガス排出口６２としてもよい。   In addition, the corrosion prevention method of the multitubular reactor of the present invention is not limited to the above-described method. For example, the replacement gas may be introduced from the gas outlet 62 and discharged from the gas inlet 60. Further, the piping of the heat medium circulation passage 22 is disconnected from the multitubular reactor 10, and the heat medium inlet 50 and the heat medium outlet 52 of the shell 42 of the multitubular reactor 10 are connected to the gas inlet 60 and the gas exhaust. The outlet 62 may be used.

以下、実施例を示す。
〔実施例１〕
多管式反応器１０への原料ガスの供給を停止し、メタクロレインの製造を終了した後、熱媒ドラム１２内の溶融塩のポンプタンク１６への供給、およびポンプタンク１６と多管式反応器１０との間での溶融塩の循環を停止した。
空気導入流路２８の弁３２および熱媒回収流路２６の弁３０を開き、ポンプタンク１６、多管式反応器１０および熱媒循環流路２２内の溶融塩を、重力によって熱媒ドラム１２に自然落下させた。 Examples are shown below.
[Example 1]
After the supply of the raw material gas to the multitubular reactor 10 is stopped and the production of methacrolein is finished, the molten salt in the heating medium drum 12 is supplied to the pump tank 16, and the pump tank 16 and the multitubular reaction are performed. The circulation of the molten salt to and from the vessel 10 was stopped.
The valve 32 of the air introduction flow path 28 and the valve 30 of the heat medium recovery flow path 26 are opened, and the molten salt in the pump tank 16, the multitubular reactor 10 and the heat medium circulation flow path 22 is removed from the heat medium drum 12 by gravity. Let it fall naturally.

弁３０および弁３２を閉じた後、２本の熱媒循環流路２２における配管接合部分を、それぞれ一箇所ずつ切り離し、図３に示すように、多管式反応器１０のシェル４２内へ窒素ガスを導入するガス導入口６０、およびシェル４２内の空気および窒素ガスを排出するガス排出口６２を形成した。シェル４２内の気相部の酸素濃度は２１体積％、水分濃度は２．５体積％であった。
ガス導入口６０からシェル４２内の反応管４０外に窒素ガス（水分０体積％）を導入し、シェル４２内の反応管４０外の気相部に存在する空気、さらには窒素ガスの一部をガス排出口６２から排出した。 After closing the valve 30 and the valve 32, the pipe joints in the two heat medium circulation passages 22 are cut off one by one, and nitrogen is introduced into the shell 42 of the multitubular reactor 10 as shown in FIG. A gas inlet 60 for introducing gas and a gas outlet 62 for discharging air and nitrogen gas in the shell 42 were formed. The oxygen concentration in the gas phase portion in the shell 42 was 21% by volume, and the water concentration was 2.5% by volume.
Nitrogen gas (moisture content of 0% by volume) is introduced from the gas inlet 60 to the outside of the reaction tube 40 in the shell 42, and air present in the gas phase portion outside the reaction tube 40 in the shell 42, and further a part of the nitrogen gas. Was discharged from the gas discharge port 62.

ガス排出口６２から排出されるガスの酸素濃度を測定し、該ガスの酸素濃度が４体積％になるまでシェル４２内に窒素ガスを通気した。通気終了直前の、ガス排出口６２から排出されるガスの水分は０．５体積％であった。通気終了後、ただちにガス導入口６０およびガス排出口６２に閉止板を取り付け、シェル４２内の気相部を外気から遮断し、気相部の水分を０．５体積％、酸素濃度を４体積％に保持した。
３０日後、シェル４２内を目視にて観察したところ、シェル４２の内壁および反応管４０の外壁の腐食は確認されなかった。 The oxygen concentration of the gas discharged from the gas discharge port 62 was measured, and nitrogen gas was passed through the shell 42 until the oxygen concentration of the gas reached 4% by volume. The moisture content of the gas discharged from the gas discharge port 62 immediately before the end of ventilation was 0.5% by volume. Immediately after the ventilation, a closing plate is attached to the gas inlet 60 and the gas outlet 62, the gas phase portion in the shell 42 is shut off from the outside air, the moisture in the gas phase portion is 0.5% by volume, and the oxygen concentration is 4 volumes. %.
After 30 days, when the inside of the shell 42 was visually observed, corrosion of the inner wall of the shell 42 and the outer wall of the reaction tube 40 was not confirmed.

本発明の多管式反応器の腐食防止方法は、メンテナンス等により多管式反応器のシェルから熱媒を抜き取った後の、シェル内の腐食防止対策として有用である。   The method for preventing corrosion of a multi-tubular reactor according to the present invention is useful as a countermeasure for preventing corrosion in a shell after the heat medium is removed from the shell of the multi-tubular reactor by maintenance or the like.

（メタ）アクロレイン、（メタ）アクリル酸等の製造装置の一例を示す概略図である。It is the schematic which shows an example of manufacturing apparatuses, such as (meth) acrolein and (meth) acrylic acid. 多管式反応器の一例を示す断面図である。It is sectional drawing which shows an example of a multitubular reactor. 図１の製造装置の熱媒循環流路にガス導入口およびガス排出口を形成した様子を示す概略図である。It is the schematic which shows a mode that the gas inlet and the gas outlet were formed in the heat-medium circulation flow path of the manufacturing apparatus of FIG.

符号の説明Explanation of symbols

１０ 多管式反応器
４０ 反応管
４２ シェル 10 Multi-tube reactor 40 Reaction tube 42 Shell

Claims (2)

複数の反応管をシェル内に配置した多管式反応器の腐食防止方法であって、
前記シェル内の前記反応管外に導入される熱媒である亜硝酸ナトリウム、硝酸カリウムおよび硝酸ナトリウムを含む溶融塩の少なくとも一部を、前記シェル内から抜いた際に、前記シェル内に形成される気相部の水分が０．５〜１体積％、かつ前記気相部の酸素濃度が４〜５体積％になるまで前記シェル内に置換ガスを通気し、前記気相部の水分を０．５〜１体積％、かつ前記気相部の酸素濃度を４〜５体積％に保持する、多管式反応器の腐食防止方法。 A method for preventing corrosion of a multi-tube reactor in which a plurality of reaction tubes are arranged in a shell,
When at least part of the molten salt containing sodium nitrite, potassium nitrate and sodium nitrate, which is a heat medium introduced outside the reaction tube in the shell, is extracted from the shell, it is formed in the shell. A replacement gas was passed through the shell until the moisture in the gas phase part was 0.5 to 1 % by volume and the oxygen concentration in the gas phase part was 4 to 5 % by volume . A method for preventing corrosion of a multi-tubular reactor, wherein 5 to 1 % by volume and the oxygen concentration in the gas phase part is maintained at 4 to 5 % by volume. 前記置換ガスが、水分が０．５体積％以下のガスである、請求項１に記載の多管式反応器の腐食防止方法。   The method for preventing corrosion of a multitubular reactor according to claim 1, wherein the replacement gas is a gas having a water content of 0.5% by volume or less.
JP2008027667A 2008-02-07 2008-02-07 Corrosion prevention method for multi-tube reactors Active JP5782213B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2008027667A JP5782213B2 (en) 2008-02-07 2008-02-07 Corrosion prevention method for multi-tube reactors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2008027667A JP5782213B2 (en) 2008-02-07 2008-02-07 Corrosion prevention method for multi-tube reactors

Publications (2)

Publication Number Publication Date
JP2009183887A JP2009183887A (en) 2009-08-20
JP5782213B2 true JP5782213B2 (en) 2015-09-24

Family

ID=41067714

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2008027667A Active JP5782213B2 (en) 2008-02-07 2008-02-07 Corrosion prevention method for multi-tube reactors

Country Status (1)

Country Link
JP (1) JP5782213B2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014103694A1 (en) * 2014-03-18 2015-09-24 Basf Se Reactor system and use thereof
CN112871182B (en) * 2019-11-29 2022-04-12 中国科学院大连化学物理研究所 Catalyst for preparing methylacrolein by oxidizing isobutene, preparation and application thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5852934A (en) * 1981-09-24 1983-03-29 Fuji Electric Co Ltd Water heater utilizing solar heat
JPH07243786A (en) * 1994-03-03 1995-09-19 Hitachi Ltd Heat storage equipment
JP4648515B2 (en) * 2000-05-02 2011-03-09 株式会社日本触媒 Reactor startup method
JP4549290B2 (en) * 2005-12-16 2010-09-22 住友化学株式会社 Multi-tube reactor

Also Published As

Publication number Publication date
JP2009183887A (en) 2009-08-20

Similar Documents

Publication Publication Date Title
EP1813346B1 (en) Multitubular reaction apparatus for contact gas-phase reaction
JP3559456B2 (en) Catalytic gas phase oxidation method and multitubular reactor
US7144557B2 (en) Multitube reactor, vapor phase catalytic oxidation method using the multitube reactor, and start up method applied to the multitube reactor
US7067695B2 (en) Method of vapor phase catalytic oxidation using multitubular reactor
RU2479569C2 (en) Method of using partial gas-phase oxidation of acrolein into acrylic acid or methacrolein into methacrylic acid on heterogeneous catalyst
EP2531446B1 (en) Process and plant for cooling sulfuric acid
JP2007521126A (en) Oxidation process and reactor using improved feed system
JP5782213B2 (en) Corrosion prevention method for multi-tube reactors
JP4430672B2 (en) Partial oxidation reactor with thermal transfer sheet device
BRPI0417591B1 (en) process for the production of acrylic acid or acrolein
CN106969953A (en) The device for making and its oxidizing fire method of a kind of organic tritium carbon sample
CN104634630A (en) Preparation system for combustible tritium and carbon-14 sample
JP5511592B2 (en) Process fluid leak detection method
CN209840154U (en) Boiler flue gas waste heat recovery system based on fluoroplastic heat exchanger
RU2001128725A (en) Device and method for heat exchange with fluidized beds
JP2014025874A (en) Process fluid incorporation detection method and heat exchange system operation method
JP2014025641A (en) Operation method of heat exchange system
WO2024154364A1 (en) Circulation apparatus and circulation method for molten salt
JP2006212629A (en) Multi-tube type fixed bed reaction device
JP6070929B2 (en) Method for reducing oxygen content in a steam generator wall tube
CN103159176B (en) Liquefied chlorine vaporizer
WO2022263139A1 (en) Process for shutting-down and heating up a tubular reactor for a catalytic gas phase reaction
JP2014024708A (en) Piping used for heat exchange system and heat exchange system
JP2008126122A (en) High-pressure reaction vessel for treating organic material and high-pressure reaction system
JP2006528612A (en) Process for producing (meth) acrolein and / or (meth) acrylic acid by heterogeneous catalytic partial oxidation of C3 and / or C4 precursor compounds in a reactor having a thermoplate apparatus

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20110201

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20120106

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20120416

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20120522

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20120713

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130226

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20130403

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20140128

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140317

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20140722

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20141009

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20141021

A912 Removal of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A912

Effective date: 20141114

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20150717

R150 Certificate of patent or registration of utility model

Ref document number: 5782213

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250