JPS6038334B2 - Equipment for generating steam in an ammonia synthesis plant - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a method for reducing the amount of water or steam between high-pressure ammonia gas in a U-shaped tube attached to a tube sheet and high-pressure water or steam in a water-steam chamber surrounding the U-shaped tube. In order to supply high temperature ammonia gas to the U-shaped pipe, a gas inlet chamber, a gas outlet chamber surrounding the gas inlet chamber, and a water-steam chamber are connected to each other. The steam generation apparatus includes a gas inlet chamber and a tube sheet separate from the gas outlet chamber.

[Conventional technology]

In this technology, the use of anti-nitration materials in the tube sheet and the U-tube is known (West German Patent No. 200
No. 7528).

[Problem that the invention seeks to solve]

However, anti-nitration materials are delicate and susceptible to stress crack corrosion on the water side.

Ferritic steel is resistant to this type of corrosion. However, this ferritic steel had drawbacks such as not having anti-nitration properties. SUMMARY OF THE INVENTION An object of the present invention is to provide a steam generation system for an ammonia synthesis plant that uses ferritic steel, which is resistant to stress crack corrosion, as a material and can overcome the problem of nitration.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides high-pressure ammonia gas in a U-shaped tube attached to a tube plate and high-pressure water or steam in a water-steam chamber surrounding the U-shaped tube. A steam generator for an ammonia synthesis plant by heat exchange between a tubesheet separating the chamber from the gas inlet chamber and the gas outlet chamber, the gas inlet chamber being spaced apart from the tubesheet, and having hot ammonia gas at one end of the gas inlet chamber from the gas inlet chamber; A plug-in pipe that supplies the U-shaped pipe is welded, the end of the plug-in pipe is loosely inserted into the U-shaped pipe, and the plug-in pipe is provided with an expanded portion that comes into gas-tight contact with the inner surface of the U-shaped pipe. An object of the present invention is to provide a steam generator characterized by the following features.

[Effect]

As mentioned above, it has a structure that is flexible against thermal expansion and contraction even when rapidly cooled, so ferritic steel is resistant to heat even if the temperature of high-temperature ammonia gas is lowered to avoid nitration. By using this for the tube sheet and U-shaped tube, it was possible to provide the above-mentioned required steam generating device that is resistant to stress cracking and corrosion.

[Embodiments] Various features of the present invention will be described in further detail below with reference to the accompanying drawings showing embodiments of the present invention.

The hot ammonia gas flows in the direction of the arrow 2 into the pre-layered anti-nitration gas inlet chamber 3 via the connecting pipe 1;
Further, in the direction of the arrow 4, a plug tube 5, which is also anti-nitration, is reached.

One end of these plug-in tubes is welded to the straightened gas inlet chamber 3, and the other end is connected in a gas-tight manner to the widening 6 in the inlet end of the U-tube 7 made of ferritic steel material. connected. The U-tube, which is welded in a tube plate 8 made of ferritic steel and flushed in a water supply air chamber 9, forms an annular gap IQ with the plug-in tube 5 at its inlet end, and these The annular gap also reaches the water-steam chamber 9, depending on the position and state of the expansion part 6 within the water-steam chamber 9.
The cooled ammonia gas is discharged from the U-tube 7 in the direction of arrow 11 into the gas outlet chamber 12 and further leaves the gas outlet chamber 12 through the connecting pipe 14 in the direction of arrow 13. The cooling water is
It is introduced into the water-steam chamber 9 in the direction of the arrow 15 through the connecting pipe 16 and then leaves the water-steam chamber 9 in the direction of the arrow 17 in the form of steam through the connecting pipe 18.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the device according to the present invention, Fig. 2 is a sectional view taken along the 0-Ro line in Fig. 1, and Fig. 3 is an enlarged view of the area x surrounded by the dashed line in Fig. 1. It is. 1, 14, 16, 18... Connection pipe, 2, 4, 1
1, 13, 15, 17...Arrow, 3...Gas inlet chamber, 5...Plug-in pipe, 6...Gender opening, 7...U
Shape tube, 8...Tube plate, 9...Water-steam room, 10...
... annular gap, 12 ... gas outlet chamber. F'9,2 Fig, DingFi9,3

Claims (1)

[Claims] 1. A steam generator for an ammonia synthesis plant by heat exchange between high pressure ammonia gas in a U-shaped tube 7 attached to a tube plate 8 and high-pressure water or steam in a water-steam chamber 9 surrounding the U-shaped tube 7. , a gas inlet chamber 3 for supplying high-temperature ammonia gas to the U-shaped pipe 7, a gas outlet chamber 12 surrounding the gas inlet chamber 3, and a water-steam chamber 9 connected to the gas inlet chamber 3 and the gas outlet chamber. a tube sheet 8 separated from the gas inlet chamber 3, the gas inlet chamber 3 being spaced apart from the tube sheet 8, the gas inlet chamber 3 being spaced apart from the tube sheet 8;
A plug-in pipe 5 to be supplied to the U-shaped tube 7 is welded, and the other end of the plug-in pipe 5 is loosely inserted into the U-shaped tube, so that the plug-in tube 5 is brought into gas-tight contact with the inner surface of the U-shaped tube 7. The steam generator is characterized in that it is provided with an expanded portion 6.