JP2000254774A - Different material welding method and tube line member change method of hydrogen reforming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube line member change method for a hydrogen reforming device not developing a welding crack to a welded part, a different material welding method high in reliability of the welded part after welding, easy in change work, short in working time and high in reliability of the welded part after changing. SOLUTION: In a different material welding method to connect by newly welding a Ni-Cr-Fe heat resistant alloy 9a to a Cr-Mo-Fe heat resistant steel 10 used for a long term in a hydrogen gas environment, after the neighborhood of a connecting part of the Cr-Mo-Fe heat resistant steel 10 is heated and subjected to dehydrogenization treatment, cladding by welding is done to the connection end of the Cr-Mo-Fe heat resistant steel 10 by using a Ni-Cr-Fe welding filler material 23, successively the cladding by welding part 24 and the connection part of the Ni-Cr-Fe heat resistant alloy 9a are butt-welded by using the Ni-Cr-Fe welding filler material 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding dissimilar materials and a method for replacing pipe members of a hydrogen reformer, and more particularly to a method for welding dissimilar materials between a pipe member of a hydrogen reformer and an inlet nozzle of a heat exchanger. The present invention relates to a method and a method for replacing a pipe member of a hydrogen reformer that has been used for a long time.

[0002]

2. Description of the Related Art The production process of a hydrogen gas producing apparatus using a catalytic conversion system is divided into four processes: a desulfurization process, a reforming process, a shift process, and a decarbonation process. Of these, the hydrogen reformer that performs reforming has a temperature of 500 to 550 ° C.
Raw gas such as naphtha and steam introduced at a pressure of 0 kgf / cm ² (about 2 MPa) are further heated to a high temperature in a reforming furnace to reform hydrogen gas (including impurities).

As shown in FIGS. 2 and 3, a general hydrogen reformer 1 has a raw material gas supply pipe 2 for supplying a raw material gas G ₁ , and an inlet manifold connected to the raw material gas supply pipe 2. 3 and a number (in practice, 100 to 200 (15 in FIG. 3) of a plurality of pipes provided vertically in the outer shell 5 of the reforming furnace and connected to the inlet manifold 4 via the inlet pigtail 6.
), An outlet manifold 9 connected to each reaction tube 7 via an outlet pigtail 8, and a heat exchanger 11 connected to the outlet manifold 9 via an inlet nozzle 10. It is configured. Each reaction tube 7 is filled with a hydrogen reforming catalyst (not shown).

Here, a steam supply pipe 3 for supplying steam S is connected to the raw material gas supply pipe 2. Further, a connection portion of the inlet manifold 4 with the raw material gas supply pipe 2 and the inlet nozzle 1 in the outlet manifold.
The reducer 4a, 9a is formed at the connection part with 0. Further, a burner 12 for heating each reaction tube 7 is provided at a predetermined location in the outer shell 5 of the reforming furnace.

Since the hydrogen gas G ₂ reformed and produced in each reaction tube 7 has a high temperature of 900 to 950 ° C., the outlet manifold 9 and the reducer thereof are exposed to the high-temperature hydrogen gas G ₂ immediately after production. The portion 9a is made of a Ni—Cr—Fe heat-resistant alloy (for example, Incoloy 800 (JIS standard NCF800) or the like; hereinafter, referred to as an Fe-based superalloy). However, since the Fe-based superalloy is a very expensive material, the inlet side nozzle 10 of the heat exchanger 11 that is also exposed to the high temperature (800 to 850 ° C.) hydrogen gas G ₂ is used at a temperature of 550 ° C. or less. Inexpensive Cr-Mo steel (Cr-Mo-F
A porous castable is lined and formed inside a pipe made of e-system heat-resistant steel).

The hydrogen reformer 1 is operated for a long time (for example, 1
When using over approximately 2.0 years), since the structure material such as outlet manifold 9 which are exposed to the reaction tube 7 and the high-temperature hydrogen gas G ₂ is heated by the burner 12 deteriorates, the hydrogen reformer 1 (inlet manifold 4,
The reaction tube 7 and the outlet manifold 9) 20 are exchanged. In this case, a reducer (inlet; hereinafter, referred to as an inlet reducer) 4a of the source gas supply pipe 2 and the inlet manifold 4
And the reducer portion (extraction / exit; hereinafter, referred to as an outlet reducer) 9a of the outlet manifold 9 and the junction portion of the introduction side nozzle 10 are cut off, and the entire pipe member 20 in the hydrogen reformer 1 is replaced. ing.

After that, a new pipe member (not shown) is incorporated into the outer shell 5 of the reforming furnace, and butt welding of the raw material gas supply pipe 2 and the inlet reducer 4a, and the outlet reducer 9a, the inlet nozzle 10 and Butt welding.

At this time, since the replacement of the pipe member 20 is performed on the existing equipment, that is, on-site work, it is preferable that the replacement work is easy and the construction period for the replacement is as short as possible. Further, since the flow of hydrogen gas G ₂ is the conduit member 20 and the inlet side nozzle 10, welding the inlet side nozzle 10 and the outlet reducer 9a must ensured.

[0009]

However, the welding between the outlet reducer 9a and the inlet nozzle 10 is a dissimilar material welding, so that the following problems occur.

[0010] Introducing nozzle 1 made of Cr-Mo steel
No. 0 has been exposed to a high-temperature hydrogen gas G ₂ atmosphere for a long period of time, and therefore has hydrogen embrittlement and temper embrittlement (475 ° C. embrittlement), and does not have sufficient strength, ductility, and toughness. Therefore, the introduction side nozzles 10 that prolonged exposure to high temperature of the hydrogen gas G ₂ atmosphere, as it is, when the butt welding of the new exit reducer 9a, the butt welds (not shown) , Welding cracks may occur.

Introducing nozzle 1 made of Cr—Mo steel
0, the strength is given by the content C, but the introduction side nozzle 10 and the content C content are smaller than that of the Cr-Mo steel.
When the outlet reducer 9a made of the base superalloy is directly welded, carbon is transferred from the inlet nozzle 10 to the outlet reducer 9a and the strength of the Cr-Mo steel is reduced. In the bending test, cracks may occur. Therefore, in some cases, build-up welding is performed using a welding material at the connection end of the introduction-side nozzle 10, but depending on the type of the welding material, a reduction in strength or cracks occurs in the welded portion during the service period.

After the build-up welding to the connection end of the introduction nozzle 10, it is necessary to perform an annealing process to remove the internal residual stress of the Cr—Mo steel and improve the structure.
This complicates replacement work and prolongs the construction period.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a dissimilar material welding method in which weld cracks do not occur in a weld portion and the weld portion after welding has high reliability.

Further, the present invention solves the above-mentioned problems, the replacement work is easy, the construction period is short, and the reliability of the welded portion after the replacement is high. Is to provide.

[0015]

Means for Solving the Problems To solve the above-mentioned problems, the invention of claim 1 is to provide a new Ni-Cr-based heat-resistant steel material which has been used for a long time in a hydrogen gas atmosphere.
In a dissimilar material welding method for welding and connecting a Fe-based heat-resistant alloy material, the vicinity of a connection portion of the Cr-Mo-Fe-based heat-resistant steel material is heated and dehydrogenated, and then the Cr-Mo-F
The connection end of the e-based heat-resistant steel material is overlaid by using a Ni-Cr-Fe-based welding material, and then the overlaid weld portion and the N
Abut the connection end of the i-Cr-Fe heat-resistant alloy material,
Butt welding is performed using an i-Cr-Fe-based solvent.

The invention according to claim 2 is characterized in that the Cr-Mo-Fe
2. The dissimilar material welding method according to claim 1, wherein after a heater for heating is wound around the connection portion of the heat-resistant steel material, dehydrogenation treatment is performed by heating at 350 to 450 [deg.] C. for 30 minutes or more.

The invention according to claim 3 is characterized in that the Cr-Mo-Fe
The dissimilar material welding method according to claim 1 or 2, wherein the overlay welding is performed in multiple layers on the connection end of the heat-resistant steel material.

According to the above method, since the dehydrogenation treatment is performed in the vicinity of the connection portion of the Cr—Mo—Fe heat resistant steel,
Weld cracking does not occur at the butt weld between the Cr-Mo-Fe heat-resistant steel material and the Ni-Cr-Fe heat-resistant alloy material. In addition, the connection end of the Cr—Mo—Fe heat-resistant steel
Since the build-up welding is performed over multiple layers using the i-Cr-Fe-based welding material, the strength of the butt-welded portion after the butt-weld is reduced without performing the annealing process on the build-up weld. No cracks occur.

According to a fourth aspect of the present invention, a source gas supplied from a source gas supply system is introduced from an inlet of a pipe member, and the reaction gas of the pipe member is heated to a high temperature to convert the source gas to hydrogen gas. In a method of replacing a pipe member in a hydrogen reformer that reforms and sends the high-temperature hydrogen gas to an inlet nozzle of a heat exchanger through an outlet of a pipe member, the hydrogen reformer to be replaced is After cutting the pipe member at the inlet end and the outlet end, connecting the inlet nozzle made of heat-resistant Cr-Mo-Fe steel of the heat exchanger separated from the outlet. Dehydrogenation treatment near the end, then
At the connection end of the introduction side nozzle, overlay welding is performed using a Ni-Cr-Fe-based welding material, and thereafter, the overlay welding portion and a new pipe member made of a Ni-Cr-Fe-based heat-resistant alloy are used. The outlet and the outlet are butt-welded and butt-welded using a Ni-Cr-Fe-based solvent.

According to a fifth aspect of the present invention, after a heater for heating is wound around the connection end of the introduction-side nozzle, the heating temperature is set to 350 to 45
The method according to claim 4, wherein the dehydrogenation treatment is performed by heating at 0 ° C for 30 minutes or more.

According to a sixth aspect of the present invention, there is provided the method of replacing a pipe member of a hydrogen reforming apparatus according to the fourth or fifth aspect, wherein the overlay welding is performed in multiple layers on the connection end of the introduction-side nozzle. .

According to the above method, no heat treatment is required except for the dehydrogenation treatment, so that the replacement work is easy, the construction period is short, and the removal of the pipe member after the replacement of the pipe member is performed. The reliability of the butt weld with the inlet nozzle of the heat exchanger is improved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

The method for replacing the pipe member 20 of the present invention applied to the hydrogen reformer 1 shown in FIGS.
First, a joint between the raw material gas supply pipe 2 and the inlet reducer (inlet) 4a and a joint between the outlet reducer (extraction and outlet) 9a and the inlet nozzle 10 in the pipe member 20 of the hydrogen reformer 1 to be replaced. Disconnect.

Thereafter, a new pipe member (not shown) is incorporated into the outer shell 5 of the reforming furnace, and the butt welding of the raw material gas supply pipe 2 and the inlet reducer 4a and the outlet reducer 9a and the inlet nozzle 10 are connected. Is performed, and the exchange of the pipe member is completed. In the present invention, at the time of this butt welding, dissimilar material welding is performed in the following procedure.

FIG. 1 is a schematic view of the dissimilar material welding method of the present invention. Here, FIG. 1A shows a partial longitudinal sectional view of a connection end of the introduction-side nozzle when dehydrogenating the introduction-side nozzle, and FIG. FIG. 1C shows a partial vertical cross-sectional view of the later-described introduction side nozzle connection end, and FIG.
1 shows a partial longitudinal sectional view of an inlet-side nozzle connecting end and an outlet reducer when butt-welding an inlet-side nozzle and an outlet reducer, and FIG. 1D shows a part of the inlet-side nozzle connecting end and an outlet reducer after butt welding. It shows a longitudinal section.

As shown in FIG. 1 (a), the dissimilar material welding method according to the present invention is performed prior to the butt welding in order to prevent the occurrence of welding cracks at the time of butt welding between the inlet nozzle 10 and the outlet reducer 9a. Introducing nozzle 1 made of Cr-Mo steel in heat exchanger 11 separated from outlet reducer 9a
In the vicinity of the connection end 0, a heating heater 22 covered with a heat insulating material 21 is wound, and at a temperature of 350 to 450 ° C.
Heat for 0 minutes or more to perform dehydrogenation treatment.

Next, as shown in FIG. 1 (b), build-up welding is performed on the connection end of the introduction side nozzle 10. At this time, it is necessary to select the type of the welding material to be subjected to the build-up welding in order to prevent strength reduction and cracking from occurring in the welded portion after the dissimilar material welding (during the service period of the hydrogen reformer 1). In addition, the thickness T of the introduction-side nozzle 10 is a medium thickness (about 20 mm) and is not so large, so that it is desirable to omit the annealing process after the build-up welding if possible.

Therefore, in the dissimilar material welding method of the present invention, considering that the constituent material of the outlet reducer 9a is an Fe-based superalloy, a Ni-Cr-Fe-based molten material (YNiCr
-3; for example, Inconel 82) 23, and build-up welding is performed over about 10 layers. At this time, the layer thickness t of the weld overlay 24 is at least about half the thickness T of the introduction-side nozzle 10.

Thereafter, as shown in FIGS. 1 (c) and 1 (d), a new pipe member 30 is incorporated into the outer shell (not shown) of the reforming furnace, and the overlay welding portion of the introduction side nozzle 10 is welded. Outlet reducer 24 made of Fe-based superalloy 24 and new pipe member 30
a, and butt welding is performed using the Ni—Cr—Fe-based solution material 23 to form the pipe member 20 in the hydrogen reformer 1.
Complete the exchange. Note that it is not necessary to perform an annealing process on the butt weld 25.

According to the dissimilar material welding method of the present invention, prior to the butt welding of the inlet nozzle 10 and the outlet reducer 9a, the dehydrogenation treatment is performed near the connection end of the inlet nozzle 10, so that the butt welding portion In 25, there is no possibility that welding cracks may occur.

Further, Ni-Cr is used as a weld material for build-up welding on the connection end of the introduction side nozzle 10 made of Cr-Mo steel and butt welding between the introduction side nozzle 10 and the outlet reducer 9a made of an Fe-based superalloy. -Since the Fe-based molten material 23 is used, the butt-welded portion 25 after the butt-welding does not suffer from strength reduction or cracking.

Further, at the connection end of the introduction side nozzle 10, 1
Because the build-up welding is applied over multiple layers around 0 layers,
The build-up weld 24 of the layer under build-up welding provides a normalizing effect to the connection end of the introduction side nozzle 10 and the build-up weld 24 of the build-up welded layer. Thus, the same effect can be obtained as in the case where the build-up welding is performed and the build-up welding is performed without performing the annealing process.

That is, according to the method of replacing the pipe member 20 of the hydrogen reforming apparatus 1 of the present invention, since heat treatment is not required except for the dehydrogenation treatment, the replacement work of the pipe member 20 on site becomes easy. At the same time, the work period for replacing the pipe member 20 is short.

Further, the connecting end of the introduction side nozzle 10 is
-Since the build-up welding is performed over multiple layers using the Cr-Fe-based welding material 23, the butt-weld (after replacement of the pipe line member 20) can be performed without performing the annealing process on the build-up welded portion 24. The strength of the butt weld 25 between the outlet reducer 9a of the pipe member 30 and the inlet side nozzle 10 of the heat exchanger 11 in the butt weld 25 is not reduced and the butt weld 2
5 is highly reliable.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the joint between the feed gas supply pipe and the inlet reducer and the joint between the outlet reducer and the inlet nozzle in the pipe member of the hydrogen reformer to be replaced are cut off.

Next, a heating heater covered with a heat insulating material is wound around a portion 80 mm from the connection end of a 16 mm-thick inlet nozzle made of the cut-off Cr-Mo steel (JIS standard SCMV-4). After that, the heating heater is turned on for 200 hours.
After the temperature is raised at a rate of not more than ℃ / hr and maintained at 350 to 450 ° C, heating is performed for 0.5 hour to carry out a dehydrogenation treatment.

Next, the temperature of the heater for heating was lowered at a rate of 275 ° C./hr or less to maintain the temperature at 200 ° C. Then, the heater for heating was removed, and the connection end of the inlet nozzle was connected to a φ2.4 mm φ made of Inconel 82. Using a molten material, build-up welding (TIG welding) with a layer thickness of 7 mm is performed over six layers. The pressure of Ar gas as a shielding gas is 2.49 MPa, the current at the time of overlay welding of the first layer is 100 to 130 A, the voltage is 14 to 16 V,
The current at the time of overlay welding of the second to sixth layers is 120 to 150 A,
The voltage is set to 15 to 17 V, and after the overlay welding, the connection end of the introduction-side nozzle is covered with asbestos and gradually cooled.

Thereafter, a new pipe member was incorporated into the outer shell of the reforming furnace, and a build-up weld of the inlet nozzle and an outlet reducer made of a Fe-based superalloy (JIS standard NCF800) of the new pipe member were added. And 2.4m of Inconel 82
Butt welding is performed using the molten material of m to complete the replacement of the pipe member in the hydrogen reformer.

A bending test of a mechanical test with a main body was performed on a butt-welded portion between the inlet nozzle and the outlet reducer. As a result, no crack was observed. In addition, a 2.94 MPa pressure resistance test and 2.16 M
As a result of performing an airtightness test of Pa, cracking, leakage, and the like were not observed.

[0041]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) By performing butt welding between the Cr-Mo steel material and the Fe-based superalloy material after performing the dehydrogenation treatment on the Cr-Mo steel material, there is no possibility that welding cracks occur in the butt welded portion. .

(2) By using a Ni-Cr-Fe-based material as a filler material for build-up welding on the connection end of the Cr-Mo steel material and butt welding between the Cr-Mo steel material and the Fe-based superalloy material, After butt welding, there is no strength reduction or cracking in the butt weld.

(3) By performing the overlay welding on the connection end of the Cr-Mo steel material in multiple layers, the annealing process can be performed with the overlay welding as it is without performing the annealing process on the overlay welding portion. The same effect as that obtained by the application can be obtained.

(4) Since the heat treatment is not required except for the dehydrogenation treatment at the time of replacing the pipe member of the hydrogen reformer, the pipe member replacement work on site becomes easy and the replacement of the pipe member is easy. Work period is short.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a dissimilar material welding method of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a hydrogen reformer.

FIG. 3 is a schematic diagram of a pipe member in the hydrogen reformer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hydrogen reformer 2 Source gas supply pipe (source gas supply system) 4a Inlet reducer (inlet) 7 Reaction tube 9a Outlet reducer (extraction outlet, Ni-Cr-Fe heat-resistant alloy material) 10 Inlet nozzle (Cr- Mo-Fe heat-resistant steel) 11 heat exchanger 20, 30 conduit member 22 for heating the heater 23 Ni-Cr-Fe-based welding material 24 overlay weld part G ₁ raw material gas G ₂ hydrogen gas

Continued on front page F-term (reference) 4E081 AA02 AA05 AA12 BA02 BA11 BA16 BA40 BA41 BB15 CA07 CA11 DA05 DA10 DA14 FA11 YH02 YH03

Claims (6)

[Claims] 1. C for a long time in a hydrogen gas atmosphere
New Ni-Cr-Fe for r-Mo-Fe heat resistant steel
In a dissimilar material welding method of welding and connecting a heat-resistant heat-resistant steel material, the vicinity of the connection portion of the heat-resistant Cr-Mo-Fe steel material is subjected to dehydrogenation treatment, and then the Cr-Mo-Fe heat-resistant steel material is heated. Overlay welding is performed on the connection end using a Ni-Cr-Fe-based welding material, and then the overlaid weld and the Ni-
The connection end of the Cr-Fe heat-resistant alloy material is abutted and Ni-
A dissimilar material welding method, characterized in that butt welding is performed using a Cr-Fe-based molten material. 2. After a heating heater is wound around the connection portion of the Cr—Mo—Fe heat resistant steel material,
The dissimilar material welding method according to claim 1, wherein the dehydrogenation treatment is performed by heating at 30C for 30 minutes or more. 3. The dissimilar material welding method according to claim 1, wherein the build-up welding is performed in multiple layers on the connection end of the Cr—Mo—Fe heat-resistant steel material. 4. A raw material gas supplied from a raw material gas supply system is introduced from an inlet of a pipe member, and a raw material gas is reformed into hydrogen gas by heating a reaction tube of the pipe member to a high temperature. In a method of replacing a pipe member in a hydrogen reformer that supplies high-temperature hydrogen gas to an inlet nozzle of a heat exchanger via an outlet of the pipe member, the pipe member of the hydrogen reformer to be replaced is provided. Is cut at the inlet end and the outlet end, and then the Cr of the heat exchanger separated from the outlet is cut off.
A dehydrogenation process is performed near the connection end of the introduction-side nozzle made of -Mo-Fe-based heat-resistant steel, and then a build-up welding is performed on the connection end of the introduction-side nozzle using a Ni-Cr-Fe-based molten material, Thereafter, the overlay welding portion is butt-joined to the above-mentioned outlet made of a Ni-Cr-Fe-based heat-resistant alloy of a new pipe member, and butt-welded using a Ni-Cr-Fe-based solvent. A method for replacing a pipe member of a hydrogen reformer. 5. The pipeline of the hydrogen reformer according to claim 4, wherein a heating heater is wound around the connection end of the introduction nozzle, and then heated at 350 to 450 ° C. for 30 minutes or more to perform dehydrogenation treatment. How to replace parts. 6. The method according to claim 4, wherein the build-up welding is applied to the connection end of the introduction-side nozzle in multiple layers.