JPS5851983B2 - Generator for fixed bed high pressure vaporization of granular fuel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a generator for fixed-bed high-pressure vaporization of granular fuel with a vaporization medium containing free oxygen.

The generator furnace for fixed-bed high-pressure vaporization of granular fuel is constructed with double walls to suppress the effects of temperature and pressure.

The annular chamber thus formed is filled with high-pressure boiling water having a slightly higher pressure than the inner chamber of the generator.

The inner wall therefore takes on the action of temperature, and the outer wall, which has a temperature slightly below the boiling point of water, takes on the action of pressure.

This principle makes it possible to construct the inner wall relatively thin, which is subjected to only a slight pressure during normal use.

This division of roles is due to the fact that during the discharge process, especially during the sudden pressure relaxation of the system during a failure, a pressure differential of several atmospheres is created between the water jacket and the generator chamber as a result of the re-evaporation of the water in the annular chamber. In order to avoid damage due to the inward bulge of the inner wall, which is subject to the constraints that must be met, the inner wall must be designed for external pressurization of approximately 0.2 to 0.4 MPa.

When the diameter of the generating furnace is large, the above-mentioned differential pressure requires a considerably thick inner wall, for example, when the diameter of the generating furnace is 4 m, the wall thickness of the inner wall already exceeds 20 mm.

These internal walls are subject to severe corrosion, especially depending on the lignite used, and in some areas of the furnace chest this corrosion can reach wear rates of several millimeters per year.

The generator can be equipped with a refractory lining to inhibit corrosion.

The disadvantages of such a lining are that the effective cross-sectional area of the generator is reduced and that there is a risk of slag formation in the generator due to the extremely high temperature inside the brickwork.

Therefore, brick masonry was abandoned and attempts were made to prevent corrosion of the inner walls by cladding or overlaying with special steel plates.

Not only are these solutions expensive, but the results achieved are not always satisfactory.

Although the causes of corrosion are not fully understood, it is obvious that high material temperatures and material stress accelerate corrosion.

An object of the present invention is to provide a fixed-bed high-pressure vaporization generating furnace with less corrosion of the metal inner wall and, therefore, a longer life.

The basis of the present invention is the problem of developing a metal inner wall fixed bed high pressure vaporization generator in which the temperature and temperature difference of the inner wall and the stress of the material are significantly suppressed.

The solution according to the invention is that in areas of high internal temperature of the reactor chest, cooling jackets are mounted on the inner wall at suitable intervals and together form a cooling chamber, which is connected to the pressure-resistant outer wall through a number of windows in the inner wall. It is characterized by communicating with an annular chamber between the inner walls of the generating furnace.

The windows are arranged around the inner wall at regular pitches and in rows with different heights above and below.

For example, in areas penetrated by pipes, the pitch and height of the windows are adapted to local conditions.

The number, size, shape, and position of the windows are sequentially matched to take into account the strength conditions of the inner wall and to obtain a uniform flow of water with little flow resistance over the entire wall surface.

To ensure cooling throughout the internal height of the cooling chamber without the formation of pockets that could fill with steam,
The windows in the interior walls are configured as follows.

That is, the lower edge of the cooling chamber is approximately at the same height as the lower edge of the water inlet, and the upper edge of the cooling chamber is approximately at the same height as the upper edge of the water outlet.

A circulation of water with a definite flow direction, with the evaporating water rising in the cooling chamber and the water flowing downward in the annular chamber, is only possible by realizing two compartments that communicate with each other.

This water circulation facilitates heat transfer between the cooling jacket and the contained water, ensuring that the temperature of the cooling jacket does not significantly exceed the water temperature.

In the current structure, the high heat loads that occur with local and temporal variations can lead to film evaporation, which in turn leads to significant overheating of the iron plates and high thermal stresses, which can be suppressed by the above.

The thermal stresses that occur in a cooling jacket under steady-state conditions are proportional to its wall thickness.

Therefore, in order to reduce the mechanical stress on the inner wall of the generator, the inner wall can be fixed and thus constructed with a small wall thickness.

The cooling jacket is fastened to the inner wall by means of retaining webs, bolts or a combination of both elements.

In addition to the retaining webs, auxiliary reinforcing webs are welded on the water side of the cooling jacket to increase the rigidity of the jacket, and at the same time serve as a guide plate for the water flow.

The two types of webs subdivide the cooling chamber into a number of individual chambers in the form of annular segments.

These cells communicate with each other in terms of flow technology.

In order to achieve a furnace chest that is in its original state without any steps in diameter, insulating brickwork was installed above and below the cooling chamber to obtain a uniform furnace chest diameter and to protect the inner walls that are not cooled very well. It is being

The solution of the invention allows new high-pressure gas generators to be created and existing high-pressure gas generators to be retrofitted.

In that case, the inner wall is both a support for the cooling jacket and a partition between the two ice compartments.

Due to the double-chamber design solution, the aforementioned corrosion-promoting factors that led to internal wall damage in the original design are reduced in the cooling jacket.

Next, the invention will be explained with reference to two embodiments based on FIGS. 1 to 7.

According to FIG. 1, the thickness of the inner wall 2 is about 3000 mm above the tip of the grid on the side of the iron plate with or without conventional laminated plates in the area of the inner wall with a particularly high heat load. A cooling chamber 5 is created by installing approximately 10 cooling jackets 3 at intervals of approximately 50 mm.

It is provided in order to ensure a constant diameter of the furnace chest 6, and in order to protect the low heat load area of the inner wall 2, which has relatively poor cooling efficiency, it is provided above and below the cooling jacket 3, that is, in front of the inner wall 2. Insulating brickwork 15 is installed.

In the first embodiment, a plurality of retaining webs 10 are attached to the inner wall 2 in order to improve the rigidity of the cooling jacket 3, as shown in FIG.
and the cooling jacket 3.

The inner wall 2 and the cooling jacket 3 form a cooling chamber 5, and the inner wall 2
and the outer wall 1 form an annular chamber 4.

The two chambers communicate with each other by windows 7,8.

For installation in an existing generator, the cooling jacket 3 and the retaining web 10 are prefabricated as segments and inserted into the furnace chest 6 through the opening 14 of the generator and welded seam 16.
A closed cooling chamber 5 is made by welding and assembling the parts.

Next, the present invention will be explained in Example 2.

According to FIG. 5, the rigidity of the cooling jacket 3 is improved by a large number of bolts 11 screwed into the inner wall 2 and welded together with the reinforcing plate 13 to the cooling jacket 3.

The inner wall 2 and the cooling jacket 3 together with the annular plate 12 form the cooling chamber 5.
The inner wall 2 and the outer wall 1 form an annular chamber 4.

The two chambers communicate with each other by windows 7,8.

To increase the strength of the cooling jacket 3, reinforcing webs 9 are welded and at the same time serve as guide plates.

cooling jacket, annular plate 12, for attachment to the generator;
The reinforcing webs 9 and the reinforcing plates 13 are inserted as prefabricated materials into the furnace chest 6 through the generator opening 14 and welded by weld seams 16 to the prepared inner wall 2 with bolts 11 to form a closed cooling chamber 5.

After the cooling chamber 5 is completed, the inner wall 2 is covered with bricks to form the furnace chest 6.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the generating furnace. FIG. 2 is a partial view of the first embodiment of FIG. 1. FIG. 3 is a sectional view taken along line A-A of Example 1 in FIG. 2. FIG. 4 is a sectional view taken along line B-B of the second embodiment of the first embodiment. FIG. 5 is a partial view of the second embodiment of FIG. 1. FIG. 6 is a sectional view taken along line AA of the second embodiment in FIG. FIG. 7 shows a cross-sectional view taken along line B--B of the second embodiment in FIG. Main partial salts and reference numbers, 2...Inner wall, 3...
...Cooling jacket, 4...Annular chamber, 5...
...Cooling room, 6...Furnace chest, 7,8...
...Window, 15...Brickwork.

Claims (1)

[Scope of Claims] 1. A generator for fixed-bed high-pressure vaporization of granular fuel using a high-pressure vaporization medium containing free oxygen, which is composed of an inner wall and an outer wall, and in which boiling water flows through an annular chamber formed by the inner and outer walls. In order to obtain an auxiliary internal water circulation, cooling jackets 3 welded to each other are pressure-tight and airtight welded to the inner wall 2 at appropriate intervals from the furnace chest 6 in the high temperature zone of the generator furnace.
There is a cooling chamber 5 between the inner walls 2 of the inner wall 2 , which communicates fluidly with the annular chamber 4 via windows 7 and 8 in the inner wall 2 and which is located above the level of the cooling jacket 3 . A generating furnace characterized in that a brick wall 15 for heat insulation is installed between an extension of the diameter of the inner wall 2 and the inner wall 2. 2. The generating furnace according to claim 1, characterized in that the cooling jacket 3 is fixed to the inner wall 2 by means of retaining webs, bolts, or a combination of both members. 3. The generating furnace according to claim 1 or 2, wherein the cooling jacket 3 is supplemented by a welded reinforcing web 9 inside the cooling chamber 5.