JPS5834176B2 - Pressure vessel with corrosion-resistant lining - Google Patents

Description

[Detailed description of the invention] The present invention involves carrying out a reaction at high temperature and high pressure such as urea synthesis,
The present invention also relates to a pressure vessel provided with a corrosion-resistant lining, which is suitably used when the reaction product is highly corrosive.

Among the pressure vessels conventionally used as high-temperature, high-pressure reaction towers, a multilayer pressure vessel shown in FIG. 1 is known as a multilayer pressure vessel that has been widely used particularly for high pressure.

In FIG. 1, 1 is a cylindrical body, 2 and 3 are mirror plates, and the body 1 includes a multilayer part 4 made of thin plates such as carbon steel wound in multiple layers, and a multilayer part 4 made of carbon steel etc. that is in contact with the inner and outer surfaces of the multilayer part 4. It is composed of an inner cylinder 5, an outer cylinder 6, and a lining 7 that is the inner surface of the inner cylinder 5.

An enlarged partial cross-sectional view of this fuselage 1 is shown in FIG.

In FIG. 2, the lining I is made up of a plurality of appropriately sized plates, which are connected through a backing metal 8 made of the same corrosion-resistant material.
They are connected by welding 9 on the backing metal 8 and are made into one piece.

In the conventional pressure vessels mentioned above, the lining materials and welding rod materials are carefully considered, the welding is carefully performed by excellent welding engineers, and even though post-welding checks are strictly carried out, Since leakage often occurs from the welded part 9, one to three detection holes 10 are provided in the circumferential direction for each stage of weld line near the lining welded part 9, as shown in Fig. 2, to prevent leakage at an early stage. Measures are being taken to detect this.

However, with this countermeasure, if the contents leaking from the welded part 9 come into contact with the carbon steel inner cylinder 5 and corrode the inner cylinder 5 before reaching the detection hole 10, this corrosive material will corrode the detection hole. The leak was discovered only after the passageway up to No. 10 was blocked and detection was no longer possible, and a large area of carbon steel had been corroded.
This has disadvantages in that it takes a lot of time for repairs, lowers the operating rate of the entire plant, and requires a large amount of repair costs.

The present invention has been made to eliminate such drawbacks, and provides a pressure vessel having a corrosion-resistant lining on the inner surface and a detection hole penetrating the outer surface near the seam weld of the lining. The backing metal arranged at the seam welding part has a groove substantially parallel to the seam weld line on the contact surface between the backing metal and the lining, and a communication hole between the groove and the detection hole. The present invention relates to a pressure vessel provided with a characteristic corrosion-resistant lining.

FIG. 3 is a diagram showing an embodiment of the pressure vessel of the present invention.

In Fig. 3, the same reference numerals as in Figs. 1 and 2 indicate the same functional parts as in Figs. 10 is a detection hole connected to a detection device (not shown) by piping,
Even the slightest leakage of contents can be detected.

FIG. 4 is an exploded view of the lining 7 and the backing metal 8. The lining 7 is a rectangular plate joined by a weld line 9.

Note that the dimension A in FIG. 4 is the diameter of the inner cylinder 5×π.

In FIGS. 3 and 4, 11.11' are grooves provided in the backing metal 8, and here two grooves are provided in parallel to the weld line 9 on both sides of the weld line 9.

Holes 12 and 12' communicate the grooves 11 and 11' with the detection holes 10, and as shown in FIG.

In the unlikely event that a leak occurs somewhere in the weld line 9, the leaked contents will pass through the groove IL11' and reach the nearest detection hole 10 from the communication hole 12, where it will be detected by a detection device (not shown). Ru.

In addition, the backing metal 8 is made of the same corrosion-resistant material as the lining 7, and is not subject to severe corrosion unlike carbon steel.
, 12' are not obstructed by corrosive substances, and leakage can be detected reliably and quickly.

Furthermore, since the leaked contents do not come into contact with carbon steel parts such as the inner cylinder 5 as in the conventional case, there is also the advantage that repair work can be reduced.

It should be noted that the present invention is not limited to the above-described multilayer pressure vessel, but can be similarly applied to a unidirectional pressure vessel, and the same actions and effects can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a view showing a pressure vessel provided with a conventional corrosion-resistant lining, FIG. 2 is an enlarged partial sectional view of FIG. 1, FIG. 3 is a view showing an embodiment of the pressure vessel of the present invention, and FIG. The figure is an expanded view of the lining indicated by numeral 7 and the backing metal indicated by numeral 8 in Fig. 3.

Claims (1)

[Claims] 1. In a pressure vessel whose inner surface is provided with a corrosion-resistant lining and which has a detection hole penetrating the outer surface near the seam weld of the lining, the backing metal arranged at the seam weld is A pressure vessel provided with a corrosion-resistant lining, characterized in that a contact surface between the lining and the lining has a groove substantially parallel to the seam weld line, and a communication hole between the groove and the detection hole.