JPS5844717B2 - Reactor for gas production by partial oxidation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing CO- and H,--containing gas by partial oxidation of dusty or liquid fuel, especially ash-containing fuel, using a free oxygen-containing gasifying agent at high temperature and pressure. Regarding reactors.

When gas is produced from dust or liquid fuel by partial oxidation, the fuel reacts with an oxygen-containing gasification agent in a flame reaction.

1200 to 160 depending on the fuel and gas usage.
A reaction end temperature of 0° C. appears, and the flame itself reaches a temperature of over 2000° C.

When using ash-containing fuels, inorganic residues from the partial oxidation process appear in a molten state.

The flame reaction takes place in a refractory, usually rotationally symmetrical reaction chamber, and the known methods differ in the arrangement of the burners and in the method of discharging the hot crude gases and slag produced.

Gas production processes of the type mentioned above are often carried out under high pressure, e.g.
It is carried out at MPa.

Reactors for high-pressure processes of this type consist, for example, of an outer pressure vessel containing the actual reaction chamber, which is formed by walls consisting of water-cooled tubes in profile.

On the side facing the flame, the tube wall is provided with a compressed material, such as a layer of silicone based on silicon carbide, compacted with a refractory material.

For example, the adhesion resistance between the compressed refractory material and the pipe is 10 mm in diameter and 1 in height.
This is achieved by a 0.5mm stud welded to the surface of the tube and extending into the compressed refractory layer.

The thickness of the compressed refractory layer is determined so that the surface temperature is lower than the freezing point of slag generated during the partial oxidation process.

During reactor operation, therefore, another layer of solidified slag forms on the surface of the compressed refractory material, which passes through the soft zone and eventually into a molten slag film which flows out.

Cooling of the tube wall is carried out using high pressure water at a temperature below the boiling point or boiling water.

The tube wall must reliably protect the outer pressure vessel from overheating by radiation and convection.

An insulating layer of refractory material is therefore often provided between the tube wall and the outer pressure vessel.

Due to the brickwork and expansion joints, due to the inevitable cracks and due to the porosity of the refractory material, there is a considerable gas permeability in this insulation layer which is not localized.

When a reactor is normally ignited at approximately atmospheric pressure and the pressure is increased to full operating pressure at high temperatures, a large stray gas path may appear that causes the pressure vessel to locally overheat during the rapid pressure rise.

A similar risk should be expected when large pressure differences appear inside the reaction chamber or in the coarse outlet line due to high performance or partial slagging.

It is true that normally the walls of the refrigerated pipes operate at a temperature above the dew point, but the temperature of the pressure vessel is below this temperature.

The gas permeability of the insulation layer allows water vapor to condense on the pressure vessel surfaces, aiding corrosion.

It has been proposed to purge brickwork or specific joints of brickwork with inert gas.

The brick-lined gas permeability, which is not localized, at least in the long term, limits the effectiveness of this type of measure to a minimum even when large amounts of scavenging gas are used.

A known embodiment of a reactor with a cooling tube wall structure is one in which individual tubes arranged in rows are connected by welded ribs along the entire length of the tubes.

The tube wall is thus airtight. The communication necessary for pressure equalization between the reaction chamber and the space between the tube wall and the pressure vessel can be effectively provided by inert gas purging to one or only a few possible openings.

Such a solution leads to a very rigid tube wall structure, another advantage of which is a simpler retainer structure and easier assembly.

However, the rigidity of the tube wall suffers from the following essential drawbacks.

Expansion and contraction of the compressed refractory material and solidified slag is inevitable during start-up and shutdown operations and during load fluctuations.

The rigid welded pipe wall structure cannot keep up with changes in the length of the stones, and the compressed refractory material often falls off from the pipe wall.

Heat loads that are several times higher on exposed parts of the tube wall can lead to the risk of local overheating.

The object of the present invention is to provide a reactor for the production of gas by partial oxidation under high pressure of dusty or liquid ash-containing fuel, the pressure vessel of which is reliably shielded against overheating and the action of crude gases, and which is continuous for long periods of time. It enables driving.

The present invention relates to a reactor for gas production by partial oxidation of dust or liquid fuel under high pressure, the reaction chamber of which is water-cooled, and a tube wall structure with compressed refractory material applied to the reaction chamber side. The outer pressure vessel is reliably protected against overheating and the effects of the crude gas atmosphere in all operating phases, its internal structure, especially the tube wall structure, is easy to assemble and disassemble, especially the compressed refractory material in the reaction chamber. Regarding the sustainability of the lining, the problem is to propose one that guarantees long-term continuous operation.

The solution according to the invention is distinguished by the following features: Constructing the reaction chamber; Planting studs on its side facing the reaction chamber; Tube walls covered with compressed refractory material, usually 1 to 5
It is surrounded by a gas-tight housing at a distance crn, and the intermediate spaces between the individual tubes of the tube wall and the housing are also filled with compressed refractory material.

Ribs are fixed to the inner surface of the housing and divide this inner surface into sections that protrude into the compressed refractory material.

These ribs are intended to avoid large areas of stray flow of hot gases along the housing wall between the compressed refractory material and the housing interior surface, despite the inevitable cracking that occurs during operation.

According to the invention, these ribs can also serve to secure a length of the tube wall without creating a rigid connection between them and the tube of the tube wall.

The housing is contained within an outer pressure vessel.

The space between the envelope of the outer pressure vessel and the housing is connected to the reaction chamber inside the housing by one or several apertures.

The outer pressure vessel is provided with one or several inert gas inlets (branch pipes) for scavenging the space between the pressure vessel and the housing.

In a preferred embodiment of the reactor according to the invention, which has a vertical cylindrical reaction chamber, the end face of which is provided with axial openings for installing the burner or crude gas and slag outlets, a cylindrical shape of the tube wall is used. The part is wound in a single or multiple coils.
It consists of one or more parallel tubes, with the refrigerant flow and outlet ends of the tubes passing through the housing and leading through the outer pressure vessel through easily removable pressure-tight bushings of known construction.

Studs are planted on the sides of these tubes facing the coil centerline.

According to the invention, one or more ribs are fixed on the inner surface of the housing surrounding the tube coils in at least one horizontal plane and project into the space between two adjacent tube coils.

According to the invention, the length of the rib corresponds to the total length of the coil.

The ends of the plurality of ribs are joined by another rib parallel to the axis, the rear outer edge of which conforms to the outer contour of the tube coil.

That is, one or several semicircular notches are made depending on the number of coils, and the radius and interval of the semicircular notches are matched to the tube radius and the tube spacing of the coils.

The space between the tube coil and the inner surface of the housing and, as is known, the side of the tube wall on which the studs forming the contour of the reaction chamber are planted is made of compressed refractory material.

According to the invention, the tube wall provided with compressed refractory material forms a structural unit with the housing, preferably by welding the housing and the inlet-to-outlet end of the tube, and also by form-fitting, and is brought as a whole into the outer pressure vessel and assembled. It can be removed from the container after removing the pressure-tight bushing for the tube end passing through the outer pressure container.

In the solution according to the invention, the amount of inert scavenging gas can be controlled with the minimum amount of scavenging gas required if the size of the connecting opening between the counterventricular chamber inside the housing and the intermediate space between the outer pressure vessel and the housing is appropriately sized. Adjustments can be made to prevent crude gas from entering this intermediate space.

During the phase of pressure increase in the reaction chamber during startup, the amount of inert gas is readjusted according to the size of the free volume of the intermediate space and the gradient of pressure increase in the reaction chamber, and the amount of inert gas is pumped from the intermediate space to the inside of the housing. The overflow velocity of should always be greater than 0.

In the solution according to the invention, sufficient elastic deformability of the tube wall is maintained by eliminating the rigid connection between the individual tubes or tube coils, so that the individual tubes are covered with a layer of solidified slag in operating conditions. It can follow the thermal expansion and contraction of the covered compressed refractory material layer, and the risk of the compressed refractory material falling off is significantly reduced.

In addition, the solution according to the invention allows a specific scavenging of the inner walls of the outer pressure vessel, so that thermal and corrosive effects on the walls of the pressure vessel due to crude gases are avoided.

Embodiments of the present invention will be described with reference to the drawings.

The reactor (Figure 1) designed for a pressure of 3.0 MPa for the gasification of pulverized lignite with an ash content of approximately 10% by partial oxidation using industrial oxygen has a cylindrical reaction chamber, and a is provided with an axial opening for attaching the burner or crude gas outlet, and has a lid 2 flanged to the pressure vessel body 3.
There is an outer pressure-resistant container 1 consisting of.

Inside the reactor is the original reaction chamber 4, in which industrial oxygen and pulverized lignite react with each other in the form of a flame at a maximum temperature of about 1400°C and the above pressure, producing C〇- and H2-containing carbon. It becomes gas.

The reaction components are fed in via a burner attachment 5 which is also provided with devices for ignition and temperature suppression in the reaction chamber.

The crude gas produced enters the discharge and cooling device 6 together with the molten slag at approximately 1400 DEG C., through which it leaves the reaction chamber and, after separating the slag, is sent to the treatment of both shoulders.

The reaction chamber is surrounded by a four-tube coil 7 formed of four tubes.

For clarity, only one strand of this coil is shown in FIG. 1, and FIG. 2 shows a portion of this coil formed of four tubes in a perspective view.

The tube of the coil is provided with a welded stud 23 on the side facing the reaction chamber, as shown in detail in FIG.

The coil of tubing 7 is surrounded by an airtight housing 8 made of sheet steel which is relatively thin compared to the jacket of the outer pressure vessel.

The distance between the outside of the tube forming the coil and the housing is approximately 2 crI'L.

The housing and the tube coil rest on a pedestal 9 which transfers the load to the bottom of the pressure vessel 1.

For convenience of assembly, the housing is provided with a hanging ring 10 for hanging with a hoist.

An intermediate space 11 between the housing 8 and the jacket of the outer pressure vessel 1 is connected to the reaction chamber 4 via an annular gap 12 between the burner mounting 5 and the housing upper opening.

A further connection exists through the lower annular gap 13 between the lower opening of the housing 8 and the crude gas discharge/cooling device 6, which is anyway largely plugged with slag during operation.

The branch pipe opening provides the possibility of purging the intermediate space 11 with nitrogen passing through the annular openings 12, 13 into the reaction chamber.

The upper and lower ends 15 of the tube forming the tube coil 7 are led to the outside through easily removable welded bushings 14 through the bottom of the pressure vessel 3 or its lid 2, although some parts are not shown in Figure 1. 1. Connected to the cooling water inlet and outlet pipes.

The water pressure inside the cooling pipe is 4.0 MPa, which is higher than the pressure inside the reaction chamber.

The temperature of the incoming filtrate is 160°C, which is below the dew point of the crude gas, which is about 150°C.

Inside the housing 8, ribs 16 are provided which are distributed vertically and are spirally formed at the same pitch as some of the tube coils 7, and are provided in the space between adjacent tubes of the coils, approximately around the center line of the tubes. It stands out even.

The length of the rib 16 corresponds to the entire length of the coil.

The ends of each rib 16, which are arranged vertically one above the other, are connected by another rib 17 mounted vertically, as shown in FIG. The radius and spacing correspond to the radius and spacing of the tubes of the coil 7 consisting of four tubes.

The vertical ribs 17 thus engage the coil 7 in a comb-like manner.

The tube coil 7 is embedded in a compressed refractory material 19 based on silicon carbide, which also fills the intermediate space 24 between the tube coil 7 and the wall of the nozzle 8 and fills the reaction chamber 4. It also covers the directed tube surface.

The thickness of the layer covering the tube on the inside, approximately 20 mm, is selected in such a way that the surface temperature of the compacted refractory material 19 is below the solidification temperature of the molten slag, which is approximately 1100 DEG C.

As the molten slag impinges on the wall, a solidified slag layer 20 is formed on the refractory compressed refractory material 19 which eventually transforms into a slag film 21 which liquefies and flows away as shown in FIG.

During operation, an equilibrium occurs with respect to the thickness of the solid and liquid slag layers.

It depends, on the one hand, on the temperature and heat transfer conditions and the efficiency of the flame reaction in the reaction chamber 4, and on the other hand, on the cooling intensity and heat conduction of the compressed refractory material 19 and the cooling pipes.

The compressed refractory material 19 and the solidified slag layer 20 form a relatively strong and rigid bond and are subject to contraction under thermal expansion, especially during the lifting and shutting process and during changes in operating conditions. A sufficiently high flexibility of the tube coil 7 is provided so that the coil can follow the thermal behavior of the compressed refractory material and the slag.

The risk of spalling of the compressed refractory material is thus significantly reduced.

On the contrary, during operation the compressed refractory material 19 and the housing 8
It is inevitable that cracks will form between the walls.

However, the protruding ribs 16 and the vertical ribs 17 in the compressed refractory material 9 prevent the hot gases from flowing over a large area behind the compressed refractory material 19, so that overheating of the housing 8 does not occur.

Rather, the housing 8 is the average temperature of the cooling water in the tube coil 7 (
(approximately 100° C.).

Condensation of water vapor is thus avoided. During normal operation, the nitrogen fed into the intermediate space 11 between the outer pressure vessel 1 and the housing 8 via the branch pipe 22 has a velocity of approximately 0.2 m/s in the annular gap 1 and the lower annular gap 13. It is determined as follows.

In the operation phase in which the pressure inside the ventricle 4 is increased, the nitrogen flow rate converted to atmospheric pressure is increased to a value slightly higher than the value of .

However, ■ is the volume of the intermediate space 11, △P/△L is the pressure increase per unit time, and Po is the normal pressure.

Inside the jacket of the outer pressure vessel 1, a nitrogen atmosphere predominates and water vapor condensation from the crude gas is avoided.

In order to limit the temperature of the outer pressure vessel 1 to a value that eliminates the labor of the workers, a thin heat insulating layer (not shown in FIG. 1) is provided on its inner surface.

[Brief explanation of the drawing]

Figure 1 is a diagram of a reactor for partial oxidation of dusty fuel under high pressure. Figure 2 shows the section of the four-striped tube coil, Figure 3 shows AB of Figure 1.
2 shows a detailed sectional view of the housing tube coil as well as of the compacting material coating and slag layer, viewed in the direction; FIG. 1...Outer pressure-resistant container, 2...Pressure-resistant container lid, 3...
Pressure-resistant container body, 4... reaction chamber, 5... burner mounting part,
6... Discharge/cooling device, 7... Tube coil, 8...
Housing Mi 9... Frame, 10... Hanging ring, 11...
- Intermediate space, 12... Annular gap, 13... Lower annular gap, 14... Penetration bushing, 15... Both ends of tube coil, 16... Rib, 17... Vertical rib, 18...
- Semicircular notch, 19... Compressed refractory material, 20... Solidified slag layer, 21... Fluid slag film, 22... Inert gas feed branch pipe, 23... Stud, 24...・Intermediate space.

Claims (1)

[Scope of Claims] 1. A reactor for the partial oxidation of dusty and/or liquid ash-containing fuels under high pressure, the reaction chamber of which consists of a flow subcooled tube wall coated with a compressed refractory material, in which each of the tube walls In those cases in which the tube is relatively elastically movable, the tube wall is surrounded at a small distance by a gas-tight housing 8, which is also housed in the outer pressure-tight enclosure 1, and which connects the housing 8 and the tube. The intermediate space 24 created between the wall and the tube is filled with a compressed refractory material 19, and ribs 16 are fixed to the inner surface of the housing 8, dividing this inner surface into several sections to form the intermediate space 24. It protrudes into the compressed refractory material 19 filled with the housing 8.
The inner reaction chamber 4 is connected by one or several openings to an intermediate space 11 between the outer pressure vessel 1 and the housing 8, into which at least one inert scavenging gas line is connected. A reactor characterized in that an inlet branch pipe 22 is provided. 2. Reactor according to claim 1, characterized in that the cylindrical part of the tube wall is in the form of a single or multiple coils. 3. On the inner surface of the housing 8, one or several ribs 16 are fixed in a spiral shape in one or several horizontal planes and at the same pitch as the tube coils 7 on the tube wall, so that two adjacent tube coils can be connected to each other. 3. The reactor according to claim 1, wherein the reactor projects into the intermediate space 24 between the reactors. The length of the 41 ribs 16 corresponds to the entire length of the coil, and both ends of the ribs 16 are fixed to the housing 8 and connected by another rib 17 parallel to the axis. 4. A reactor according to claim 3, characterized in that there is a semicircular notch whose radius and spacing are adapted to the portion of the tube wall. 5. Any one of claims 1 to 4, characterized in that the tube wall on which the compressed refractory material 19 is applied and the housing 8 are joined together so that they can be installed in the outer pressure vessel 1 as a structural unit. Reactor according to item 1.