JPS6272964A - Pressure container provided with liner on inner wall thereof - Google Patents

Abstract

PURPOSE:To remarkably enhance the buckling strength of a liner applied on the inner surface of a pressure container used for a chemical reactor in an urea synthesizing tower, etc., by making a reinforcing ring made of materials having a linear expansion coefficient which is larger than that of the liner, into contact with the inner surface of the liner. CONSTITUTION:A liner made of titan is provided on the inner surface of a pressure container, and a reinforcing liner made of a stainless steel having a linear expansion coefficient larger than that of the material of the liner, is made into contact with the inner surface of the liner. That is, there are provided two semicircular ring halves 1 made of, for example, SUS. One of the coupling sections 2 of the ring halves 1 is formed therein with a tenon and a mortise and is fixed while the other coupling section 1 is formed therein with a gap for a wedge 3. These ring halves 1 are set on the inside of the liner. The wedge made of the same material so that of the ring halves 1 is driven into the wedge gap 3 so that the ring 1 is made contact with the inner surface of the liner. Accordingly, the degree of thermal expansion of the ring haves 1 is greater than that of the liner when the inside temperature of the container is raised, and therefore, the ring haves 1 reinforce the liner at the inside of the latter, thereby it is possible to restrain external deformation of the surface of the pressure container due to buckling.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Advantages L The present invention is directed to a pressure vessel having a liner on the inner wall, more specifically, to improve the corrosion resistance of a liner which is reinforced by a ring that is in contact with the inner surface. Regarding pressure vessels.

BACKGROUND OF THE INVENTION Conventionally, pressure vessels such as those used in chemical reaction devices such as urea synthesis towers have been provided with corrosion-resistant liners to protect the inner walls from corrosion. As materials for pressure vessels that require such corrosion resistance, steel is usually used for the pressure-resistant part, while liner materials include Cu%SUS, Ti, and T.
A etc. are used.

However, all such liner materials are expensive, and from an economical design point of view, it is desirable that the thickness of the liner material be as thin as possible.

On the other hand, thin liners have a high risk of buckling due to compressive stresses such as negative pressure and thermal stress. Particularly when Ti is used as the liner material, the liner and container wall cannot be easily attached by welding.
Loose liners, that is, the liner is not fixed to the outer container and are free, or the liner is attached to the outer container via a clad steel plate.

Problems to be Solved by the Invention However, in a pressure vessel in which such a conventional liner is provided on the inner wall, if a loose liner is used, the buckling strength is low and buckling collapse occurs. If it is attached to a container, it is highly greasy and will cause fatigue failure due to stress concentration at welded parts.

Means for Solving the Problems In view of the above-mentioned problems, the present inventors aimed to obtain a pressure vessel based on a rational design in which the liner is appropriately reinforced and bonded to the container wall, and buckling of the liner is suppressed. As a result of various studies, we have completed the present invention.

That is, the present invention relates to a pressure vessel having a liner on the inner wall, the pressure vessel having a liner on the inner wall, wherein the hli strong resilling liner is made of a material having a higher linear expansion coefficient than the liner material. It provides:

Titanium or the like may be used as the liner material for the pressure vessel of the present invention. These liners are not bonded to the inner surface of the container and are free.

Next, the reinforcing ring arranged on the inner surface of these liners is made of a material having a higher coefficient of linear expansion than the above-mentioned material constituting the liner. As such a material, for example, stainless steel can be used.

The shape of the reinforcing ring may be a ring in which the entire circumference is divided into two or more parts, and its cross-sectional shape may be circular, rectangular, or the like.

In the pressure vessel of the present invention, any method may be used to arrange the reinforcing ring on the inner surface of the liner, but it is preferable to use the following method, for example.

First, as shown in FIG. 1, two rings (1) (for example, 5O9) whose circumference is approximately divided into two are provided. One joint (2) of the 2g split ring is fixed as a mortise and tenon, and the other joint is provided with a wedge (3) gap. After setting the ring inside the liner, drive a wedge (3) made of the same material as the ring into the wedge gap,
The ring is brought into contact with the liner from the inside. The amount of wedge driving should be such that the ring does not come off the inner wall of the liner, and no joining means such as welding is performed between the liner shell and the ring. The wedge is preferably fixed to the ring by spot welding (4) as shown in FIG.

In the pressure vessel of the present invention, when the temperature inside the vessel rises, the thermal expansion of the ring is superior to that of the liner, reinforcing the liner from the inside and restraining out-of-plane deformation due to buckling. That is, the reinforcing effect of the ring of the pressure vessel of the present invention is as follows.

For example, under the general operating conditions of a pressure vessel as shown in Figure 3, if a Ti liner that is not fixed to the vessel and is in a free state is reinforced with SUS ring +4, it will tighten from the inside of the ring due to the upper limit of temperature. The force increases when attached, and a strong HLT force is generated against buckling. That is, a stress as shown in equation (1) is generated in the circumferential direction of the ring.

σ=EoαO'l−E, α, T (1) where E, Young's modulus α. Coefficient of linear expansion of steel E, Young's modulus of SUS α, Coefficient of linear expansion of SUS T Difference between temperature during container operation and room temperature, that is, E o = 2, l X I O' (kg/mm2
)α. -taxto-8 E+=2. l X l O' (kfF/fight 2) α, = 1
7XIO-'' T=200°C σ=8 (kg/mm'), and as the temperature increases, the action of reinforcing the liner by the ring increases.

Effects of the Invention At high temperatures, the liner twist ring expands 4. Because the two-sided reinner ring is restrained from the inside by the ring, the buckling strength of the liner is dramatically increased. Furthermore, by reducing the distance between the rings, the buckling strength is significantly improved. Furthermore, since the ring is not welded to the liner, there are no problems with stress concentration or fatigue strength at the welded portion, and the ring can be replaced relatively easily by, for example, removing spot welds from the wedge.

[Brief explanation of drawings]

Is Figure 1 used in the present invention? +Ii strong ring -
FIG. 2 is an enlarged view showing a wedge portion of a reinforcing ring, and FIG. 3 is a graph showing a specific example of operating conditions of a pressure vessel. The main symbols in the figure are as follows. 1. Ring, 2. Continuous part, 3. Wedge.

Claims (2)

[Claims] (1) A pressure vessel with a liner on the inner wall, characterized in that a reinforcing ring made of a material having a higher coefficient of linear expansion than the liner material is brought into contact with the inner surface of the liner. (2) The pressure vessel according to item (1) above, wherein the liner is made of titanium and the reinforcing ring is made of stainless steel.