DE102011117812A1 - Fluidized bed reactor - Google Patents

Abstract

In order to be able to fluidize a fluidized-bed reactor (10) simultaneously or else alternately by means of different fluidization media (11, 12), the supply lines for the various fluidization media (11, 12) are combined in a supply tube (8) whose cross-section is divided into several chambers (1, 2, 3) is divided, which form the individual supply lines and in the fluidized bed (15) usually run horizontally. The outlet openings (4, 5, 6) are arranged in the walls (9) of the chambers (8) and directed generally obliquely downwards outside.

Description

I. Field of application

The invention relates to a fluidized bed reactor, in particular its fluidization.

II. Technical background

In a fluidized bed, a bed of solids is blown from below with a fluidizing medium so that the adhesion forces between the particles of the bed are overcome and the particles float in the flow of the fluidizing medium. This condition is called fluidized. If particles are entrained and discharged with the fluidizing stream, this is referred to as a circulating fluidized bed, otherwise from a stationary fluidized bed. When operating a fluidized bed, it is desirable that all areas of the solids bed are blown evenly to avoid imbalances.

For this purpose, nozzles are arranged at a narrow distance at the lower end of the fluidized bed, through which the fluidizing medium is blown into the solids bed. This level is also called fluidization level.

Below the fluidization level, the solids bed is in a non-fluidized state. It is very important that all nozzles are arranged at the same height, since otherwise imbalances are unavoidable. Internals in the fluidized bed, which are arranged above the fluidization, are usually loaded erosive.

An erosive load can be minimized only with purely vertical installation of the internals in the fluidized bed, but this is usually structurally not possible.

If combustion or gasification reactions of solids now take place in the fluidized bed, ashes always remain as reaction products, which are small-sized in the fluidized bed and discharged with the gases emerging upwards from the fluidized bed.

Since the solids introduced into the fluidized bed can also contain impurities that are not ground and discharged small, it is customary to provide a deduction for impurities at the lower end in the fluidized bed. This trigger can be provided areally below the fluidization level. In this case we speak of an open nozzle bottom. If there is essentially a closed bottom with small discharge openings below the fluidization level, this is referred to as a closed nozzle bottom.

Among other things, when stopping a fluidized bed can trickle back into the nozzles of the supply lines for Fluidisierungsmedium bed material, so that it makes sense to provide a deduction of bed material from the nozzles.

It is particularly advantageous if the nozzles for injecting the fluidization medium occupy only a small part of the base area of the bottom, since then there is a large, free withdrawal cross section under the fluidized part of the solid charge, which opens into a non-fluidized, solid part of the solid charge, which can be pulled off slowly down and over which then the impurities can be deducted with.

The nozzles must be connected to supply lines for the fluidization medium, which in turn lay a part of the free exhaust cross section.

In this case, the nozzles for injecting the fluidization medium must open below the supply lines and are then usually integrated in the supply line. Such a supply line, in which the nozzles are integrated directly flowing down, is also called nozzle rod.

In order to achieve a uniform fluidization of the fluidized bed, it is necessary that the nozzle rods have a constant pitch. The space between two nozzle rods is thus fluidized halfway from the left, half from the right nozzle rod.

A particular problem arises when a fluidized bed is fluidized by several media that must not mix before entering the fluidized bed, but then must be mixed to ensure even distribution without imbalances.

The installation of multiple levels of supply lines usually forbids because of the erosive load. Likewise, an arrangement of nozzles at the edge of the fluidized bed in the fluidized area, above the fluidization level, also does not lead to the desired result, since this can not achieve a uniform mixture over the bed cross-section.

III. Presentation of the invention

a) Technical task

It is therefore the object of the invention to provide a fluidized bed reactor in which the outlet openings for Fluidisierungsmedium of several different Supply lines are fed and yet a design is chosen which minimizes the erosive load on the supply lines and still allows a good operation of the fluidized bed and in particular a good deduction of the bed material.

b) Solution of the task

This object is solved by the features of claim 1. Advantageous embodiments will be apparent from the dependent claims.

By dividing the supply tube for fluidizing medium in its cross section into different chambers, which are used as separate supply lines for the supply of the different fluidization media, the outer surface of the supply lines, which must withstand an erosive load, already significantly reduced and also considered in the supervision the fluidized bed, which is covered by the supply lines and is not available as a deduction minimized. By here outlet openings are arranged in the walls of the supply pipe, a particularly space-saving and simple construction is also chosen. In this case, the outlet openings may be formed as nozzles, so have an at least partially tapered cross-section, but also have the shape of pipe socket with a constant internal cross-section.

The outlet openings or nozzles can be arranged either at the same height and next to each other or in several levels one above the other, then in particular the outlet openings each exactly perpendicular to each other, or it can also be a mixed form of the two arrangements are selected.

Normally, each outlet port communicates with one of the chambers of the supply lines, so that only one type of fluidizing medium emerges from each outlet port. In special cases, where the mixture of the different fluidization media should already take place in the supply pipe and before discharge into the fluidized bed, individual outlet openings can also be connected to a plurality of the chambers and fed from these simultaneously.

In order to facilitate the withdrawal of bed material, which passes through the outlet openings in the chambers of the supply tube when switching off the fluidized bed, the chambers may have a vent for bed materials in its lower region and for this purpose, in particular the bottom of the corresponding chamber a conical downward have tapering to the discharge opening towards cross-section, at which then the bed material automatically converges.

In order to minimize the ingress of bed material and also to minimize the erosive load on the supply pipe, the discharge direction for the fluidizing medium at the discharge openings is directed obliquely outwards from the individual chambers.

The chambers of the supply pipe can be arranged only one above the other, only next to each other or both side by side and one above the other within the supply pipe, depending on both the number of required fluidization media and the cross sections required for this purpose.

Likewise, the fluidized-bed reactor according to the invention may have an open or closed nozzle bottom, that is to say the latter having a flat bed material withdrawal below the fluidization plane which extends over a plurality of supply pipes.

c) embodiments

Embodiments according to the invention are described in more detail below by way of example. Show it:

Figure 1: a first design of a supply pipe,

Figure 2: a second design of a supply pipe,

Fig. 3: a third design of a supply pipe,

Figure 4: a fourth design of a supply pipe,

Picture 5: several supply pipes according to picture 1 next to each other and

Figure 6: a section through the bed area of a fluidized bed reactor.

Figures 1 to 4 each show a specific design of a supply pipe 8th in each case in the right part in cross section and in the left part in the side view.

In picture 1 has the supply pipe 8th a rectangular cross section, which is less important for the present invention, and within this cross section a division into two superimposed chambers 1 . 2 , which extend from the right to the left wall. From each of the chambers 1 . 2 protrude left and right outlet openings 4 in the form of in this case pipe socket from the upper chamber 1 and outlet openings 5 in the form of pipe sockets from the lower chamber 2 obliquely downwards outward, from which then the fluidizing medium 11 flows, which over the respective chamber 1 . 2 is supplied.

As the side view shows, the outlet openings 4 on the one hand and 5 on the other hand evenly spaced adjacent to each other, and the upper outlet openings 4 are located exactly above the lower outlet openings 5 ,

Also, the inclination of the pipe socket of the outlet openings 4 . 5 is for both chambers 1 . 2 the same.

The solution according to Fig. 4 differs from that according to Fig. 1 in that here the supply pipe 8th three superimposed chambers 1 . 2 . 3 has, from each of which outlet openings 4 . 5 . 6 in the form of pipe sockets on both sides inclined downwards protrude analogous to the solution according to Figure 1.

The supply pipe 8th according to figure 3 differs from that of figure 1 in that from the supply pipe 8th on the left and right side - viewed in cross section of the supply pipe 8th - Only in each case one row behind the other lying pipe socket 4 . 5 from the supply pipe 8th protrude, all of which are at the same height and / or end at the lower end, but have a different length and thereby - in the direction of the supply pipe 8th alternately - once with the upper chamber 1 and once with the lower chamber 2 be connected and fed by each of these.

Figure 2 shows a supply pipe 8th , whose cross-section in two adjacent chambers 1 . 2 is divided. Each of the two chambers 1 . 2 has a conically tapered bottom, the - at its lowest point - a vent 7 for having got into the chamber bed material.

Outlets or pipe socket 4 . 5 with outlet openings are arranged on both sides of the pipe cross-section and in two levels one above the other, in turn, the two superposed pipe sockets 4 . 5 due to their different length with their rear end with one of the two chambers 1 . 2 be connected and fed by these, so that on each side of the supply pipe 8th both fluidization media 11 . 12 can escape.

Figures 5 and 6 show the arrangement of the supply pipes 8th , in this case in the design of Figure 1, in a fluidized bed reactor 10 :
In 6 is the entire lower portion of the fluidized bed reactor 10 So in the field of fluidized bed 15 represented with those in the fluidized bed 15 , so in bed material, adjacent supply pipes 8th ,

How better in the enlarged view of the 5 to recognize, flows the respective fluidizing medium 11 . 12 obliquely downwards outward from the respective outlet openings 4 . 5 out.

This exit direction 13 However, it is not preserved, but by the meeting of two oppositely directed exit directions 13 and additionally the upwardly looser bedding material in the fluidized bed 15 turns the flow direction upwards, so that at some distance below the supply pipes 8th forms a solid, non-fluidized part of the bed, while the overlying part forms the actual fluidized bed 15 represents, extending from below the supply pipes 8th usually far above the supply pipes 8th extends.

LIST OF REFERENCE NUMBERS

1

chamber

2

chamber

3

chamber

4

Outlet opening, pipe socket

5

Outlet opening, pipe socket

6

Outlet opening, pipe socket

7

vent

8th

supply pipe

9

wall

10

Fluidized bed reactor

11

fluidization

12

fluidization

13

exit direction

14

Longitudinal center plane

15

fluidized bed

Claims (9)

Fluidized bed reactor ( 10 ) with outlet openings ( 4 . 5 . 6 ) for fluidization medium ( 11 . 12 ), which are supplied from different supply lines, characterized in that the supply lines the adjacent chambers ( 1 . 2 . 3 ) of a supply tube divided into chambers with its cross-section ( 8th ) are. Fluidised bed reactor according to claim 1, characterized in that the outlet openings ( 4 . 5 . 6 ) in the walls ( 9 ) of the supply pipe ( 8th ), in particular formed as nozzles, are arranged. Fluidized bed reactor according to one of the preceding claims, characterized in that the outlet openings ( 4 . 5 . 6 ), in particular the nozzles, are arranged at the same height and next to one another. Fluidized bed reactor according to one of the preceding claims, characterized in that the outlet openings ( 4 . 5 . 6 ), in particular the nozzles, in several levels one above the other, in each case exactly above one another, are arranged. Fluidized bed reactor according to one of the preceding claims, characterized in that a single outlet opening ( 4 . 5 . 6 ), in particular nozzle, with a plurality of the chambers ( 1 . 2 . 3 ) and is supplied from these simultaneously, in particular by the cross-section of the outlet opening ( 4 . 5 . 6 ) is subdivided into individual cross sections, each with one of the chambers ( 1 . 2 . 3 ) keep in touch. Fluidised bed reactor according to one of the preceding claims, characterized in that in the lower region of the individual chambers ( 1 . 2 . 3 ) a vent ( 7 ) is arranged for bed material and in particular the underside of the chambers ( 1 . 2 . 3 ) in particular has a conically downwardly tapering cross-section. Fluidised bed reactor according to one of the preceding claims, characterized in that the outlet direction ( 13 ) for the fluidization medium ( 11 . 12 ) from the outlet openings ( 4 . 5 . 6 ), in particular the nozzles, of the individual chambers ( 1 . 2 . 3 ) obliquely outwards with respect to the vertical longitudinal center plane (FIG. 14 ) of the supply pipe ( 8th ). Fluidized bed reactor according to one of the preceding claims, characterized in that the chambers ( 1 . 2 . 3 ) within the supply pipe ( 8th ) exclusively on top of each other, exclusively next to each other or both above and below each other. Fluidized bed reactor according to one of the preceding claims, characterized in that the fluidized bed reactor ( 10 ) has an open or closed nozzle bottom.

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