AU666016B2

AU666016B2 - Fluidized bed reactor for cooling or heating granular solids by an indirect heat exchange

Info

Publication number: AU666016B2
Application number: AU41497/93A
Authority: AU
Inventors: Jurgen Emmel; Wolfgang Frank; Wladislaw Lewandowski; Wolfgang Scheler; Hans-Jurgen Weiss
Original assignee: Metallgesellschaft AG
Current assignee: GEA Group AG
Priority date: 1992-06-26
Filing date: 1993-06-25
Publication date: 1996-01-25
Anticipated expiration: 2013-06-25
Also published as: DE4220952A1; GB2268261B; DE4220952C2; GB2268261A; AU4149793A; GB9313029D0

Description

VIUUIU1 1 28101S Regulation 3.2(2)

A'USTRALIA

Patents Act 1990 AA0 6 0 16

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Cf.. C *4 C j #4 4 Application Number: Lodged: Invention Title: FLUIDIZED BED REACTOR FOR COOLING OR HEATING GRANULAR SOLIDS BY AN INDIRECT HEAT EXCHANGE The following statement is a full description of this invention, including the best method of performing it known to :-US FLUID BED REACTOR FOR COOLING OR HEATING GRANULAR SOLIDS BY AN INDIRECT HEAT EXCHANGE

DESCRIPTION

This invention relates to a fluidized bed reactor for the thermal treatment of granular solids, comprising piping contained in the reactor within the fluidized bed and serving to conduct a heating or cooling fluid for effecting an indirect heat exchange between the heating or cooling fluid and the solids.

Such a fluidized bed reactor is known, from German Patent 2901723 and the corresponding U.S. Patent 4,295,281 and from German Patent 3644806. In the known fluidized bed reactors, granular solids, particularly brown coal, are heated and are thus substantially dried. The reactors comprise fixedly installed piping, through which flows a heating fluid, such as steam, in order to supply the required energy to the fluidized bed.

It is an object of the invention so to design the fluidized bed reactor S described first hereinbefore that individual sections of the piping can be disconnected and can be replaced without a large expenditure whereby the individual sections of piping are approximately evenly spaced apart. This is accomplished in accordance with the invention in that the reactor comprises at least two spaced apart pipe plates, which are detachably fitted in apertures in the reactor wall, the inlet and outlet ends of a plurality of fluid-conducting pipes extend through each pipe plate, and each pipe plate and the associated pipes S' constitute a heat exchanger unit. Adjacent heat exchanger units are disposed on substantially the same level, and extend opposite to one another such that they can be approximately evenly spaced.

The fluidized bed reactor designed in accordance with the invention may be used to cool or heat the granular solids of the fluidized bed. If the fluidized bed is to be heated, a heating fluid, such as a hot gas, steam or a hot liquid, will be conducted through the pipes. In case the fluidized bed is to be cooled, a cooling fluid, such as water, will be supplied to the pipes.

At least one of the pipe plates is desirably provided adjacent to the inlet ends of the pipes with an entrance chamber and in that case at least one of the g pipe plates is provided with an exit chamber adjacent to the outlet ends of the pipes. Adjacent pipes of a given heat exchanger unit are desirably approximately evenly spaced apart. The pipes which are associated with different pipe plates, and therefore belong to different heat exchange units, need not be parallel but may extend at any desired angle to each other.

According to a further feature of the invention at least two adjacent heat exchanger units comprise pipe plates fitted in the reactor wall in apertures which are obliquely opposite to each other. Briefly stated, such heat exchanger units extend approximately opposite to each o *oo** o* p

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3 other. If it is desired to accommodate in the reactor as of fluidized bed volume, many pipes as possible per cubic meterValternate hat exchangers arranged on the same level will extend opposite to each other. In that case it will be possible to provide on a given level, 10 to 50 heat exchanger units which extend opposite to each other in alternation.

Further features of the fluidized bed reactor will be explained with reference to the drawing, in which Figure 1 is a schematic longitudinal sectional view showing a fluidized bed reactor, Figure 2 is a longitudinal sectional view taken on line A-A in fig ire. 3 and showing two hbat exchanger units, Sj Figure 3 is a transverse sectional view taken on line R-R in Figure 2, and 0 o Figure 4 is a longitudinal sectional view taken on line C-C in Fioure 3, The fluidized bed reactor 1 shown in Fioure 1 comprises vertical outside walls la and 1b, which enclose a fluidized"bed 2. Fluidizing qas is suoplied under oresmre through a line 3 and is distributed into the fluidized bed 2 thorugh a grate 4 provided with orifices. The granular solids which are to be thermallv treated are supplied to Sthe fluidized bed through line 5. Treated solids are withdrawn from a collecting chamber 6 below the orificed grate 4 and are removed in a line 7 from the reactor Solids-con- 4 taining fluidizing gas leaves the reactor in a duct 8 and enters dedusting means, which are known per se and are not shown and consist, of a cyclone and/or an electrostatic precipitator. The solids which have been separated from the fluidizing gas may be removed as treated solids from the process or may be recycled to the fluidized bed entirely or in part this has also not been shown in the drawing.

In the subsequent description it will be assumed that heat is indirectly supplied to the fluidized bed P by a heating fluid, which flows in the fluidized bed through pipes 10 and 11. Analogously, a coolino fluid might be conducted through the pipes. The hbatinq fluid is supplied from the outside in lines 10a and 11a and then first enters an 9* entrance chamber 10b or 11b before it flows throuoh the associated pipes. At the outlet end of the pipes, an associated exit chamber 10c or lic is provided, from which the cooled heating fluid is discharged in lines 10d and lid. The components designated by the reference characters 10, D1a, 10lb, 10c, and 10d belonq to the upper heat exchanger unit, and the components designated by the reference characters 11, 11a, 11b, 11c and lid belong to a second heat exchanoer unit disposed below the first. The pipes of both units have a oradient throuQhout their lenoth so that a liquid contained therein will always be drained.

5 Fioures 2 and 3 illustrate how two or more heat exchanger units may be designed and how they may be arranged, in the reactor. Each unit can be separately turned on and off and when the reactor has been shut down each unit can be removed from the reactor As a result, servicing work can be performed more ouickly and will be simolified. In Figure 2 a part of the lower unit comprising the pipes 11 has been removed from the reactor Each unit ocnprises a pipe plate 9, see Figures and 3, through which the inlet and outlet ends of the pipes associated with the unit extend. In Figure 1 the pipe lates 9 have been omitted for the sake of simplicity. The pipe plate is fitted in an aperture 15 in the side wall of the reactor and is seoarably joined to that wall, by bolting or welding. The pioe plate 9 is so shaped that it will entirely fill the aperture 15 so that the inside surface of the reactor wall is as smooth as possible there. In case of such a smooth inside surface, a formation of crusts as well as disturbances in the distribution of the fluidizino gas will be avoided. The entrance chambers 10b and 11b and the exit chambers 1Oc and 1ic explained with reference to Figure 1 are orovided on the otuside of the tube plate 9.

The oines are schematically represented as simole lines in Figures 1 to 4. It will be understood that the number of pipes included in a heat exchanger unit may be selected substantially as desired.

It is apparent fnom Figures 2 and 3 that the tube plates 9 of adjacent, juxtaposed or superposed, heat exchanger units 9 are fitted in the reactor walls la and lb in apertures 15 which are obliquely opposite to each other so that the distance between adjacent units may be rather small.

Figure 3 shows an important modification of the invention. Alternate heat exchanger units disposed on the same level extend opposite to each other and may be stated to alternate on the same level. In that case the pipes of the uoper unit in Figure 3, the oioes 12 of the intermediate unit and the pipes 13 of the lower unit in Fiqure 3 can be closely packed in the fluidized bed on the same level.

It may be sufficient in practice co provide only *0 juxtaposed units (corresponding to oips 10, 12 and 13 in Figure 3) in the fluidized bed reactor and to omit other, units lower\(oipes 11 of Figures 1 and 2).

If the pipes have a gradient throughout their lenoth, the most closely adjacent pious 13 of adjacent units will be very close to each other at certain locations indicated by a circle 20 in Figure 4. Care must be taken in practice that the distance between adjacent pioes at said locations is larger than the laroest particle diameter which may occur in the fluidized bed so that aarticles will not be clamoed and retained between the oipes.

Claims

1. A fluidized bed reactor for the thermal treat- ment of granular solids, comprising piping contained in the reactor within the fluidized bed and serving to conduct a heating or cooling fluid for effecting an indirect heat exchange between the heating or cooling fluid and the solids, characterized in that the reactor comprises at least two soaced apart pipe plates, which are detachably fitted in apertures in the reactor wall, the inlet and outlet ends of a olurality of fluid-conducting pipes extend through each pipe plate, and each pipe olate and the associated pipes can- stitute a heat exchanoer unit.

2. A fluidized bed reactor according to claim 1, characterized in that at least one of the pipe plates is provided with an entrance chamber adjacent to the inlet ends of the pipes.

3. A fluidized bed reactor according to claim 1 *9*U or 2, characterized in that at least one of the pipe plates is provided with an exit chamber adjacent to the cutlet ends of the pipes. h. A fluidized bed reactor according to any of claims 1 to 3, characterized in that adjacent pipes of a heat exchanger unit are spaced aoproximately equal distances aoart. A fluidized bed reactor according to any of claims 1 to 4, characterized in that the icea plates of at THE CLAIMS DEFINING THE INVENTION ARE AS FOLQLS: 1. A fluidized bed reactor for heating of granular solids, comprising piping contained in the reactor within the fluidized bed and serving to conduct a heating fluid for effecting an indirect heat exchange between the heating fluid and the solids of the fluidized bed, wherein the reactor comprises at least two spaced apart pipe plates, which are detachably fitted in apertures in the reactor wall, the inlet and outlet ends of a plurality of fluid-conducting pipes extend through each pipe plate, and each pipe plate and the associated pipes constitute a heat exchanger unit and adjacent heat exchanger units disposed on the same level extend opposite to each other. 0: 2. A fluidized bed reactor according to claim 1, characterized in that at least one of the pipe plates is provided with an entrance chamber adjacent to the inlet ends of the pipes. C CC.. 3. A fluidized bed reactor according to claim 1 or 2, characterized in that at least one of the pipe plates is provided with an exit chamber adjacent to the outlet ends of the pipes. *Soo*:

4. A fluidized bed reactor according to any of claims 1 io 3, characterized in 6 that adjacent pipes of a heat exchanger unit are spaced approximately equal S: distances apart. S A fluidized bed reactor according to any of claims 1 to 4, characterized in that the pipe plates of at il17 least two adjacent heat exchanger units are fitted the reactor wall in apertures which are obliquely opposite to each other. characterized in that ad'a, excha~nger unit~sdis- DATED this 25th day of June 1993. M92ALLGESELLSCRAFT AKTIENGESELLSCHAFT WATERMARK PATENT "THE ATRIUM" 290 BURWCOD ROAD HAWTHORN. VIC. 3122 TRADEMARK ATTORNEYS we a *0*e 'I X. S9 ABSTRACT Adjacent to the fluidized bed the fluidized bed reactor comprises at least two heat exchanger units, each of which comprises a pipe plate, which is separably fitted in an aperture in the reactor wall. The inlet and outlet ends of a plurality of fluid-conducting pipes extend through each pipe plate. At least one of the pipe plates is preferably provided with an entrance chamber adjacent to the inlet ends of the pipes and with an exit chamber adjacent to the exit ends of the pipes. so 4. Oe S