Method and system for separating a hot gas flow that is charged with material and method for processing oil shale material

Abstract

The separation according to the invention of a material-laden hot gas stream substantially consists of the following method steps: the material-laden hot gas stream is separated in a first separator into a gas stream and a material stream, wherein the material stream contains a coarser and a finer fraction, and the material stream is then classified in a classifier with at least a proportion of the gas stream, the coarser fraction of the material stream being discharged, while the finer fraction is carried away together with the gas stream separately from the coarser fraction.

Claims

1. A method for processing oil shale material comprising the steps of: a. feeding the oil shale material to a retort, b. thermally expelling hydrocarbons from the oil shale material such that oil shale ash remains, c. heating the oil shale ash outside the retort together with a gas stream to form a material-laden hot gas stream, d. separating the material-laden hot gas stream in a separator, the material-laden hot gas stream being separated into a hot gas stream and a material stream, the material stream containing a coarser and a finer fraction mixed together, e. introducing the material stream and at least a portion of the hot gas stream to a classifier and classifying the material stream with the hot gas stream in the classifier, thereby separating the coarser fraction of the material stream from the finer fraction of the material stream, f. introducing the coarser fraction into the retort, g. carrying away the finer fraction together with the hot gas stream separately from the coarser fraction.

2. A method according to claim 1, characterised in that the finer fraction of the material stream is fed together with the hot gas stream to a second separator, where the finer fraction is separated from the gas stream.

3. A method according to claim 1, characterised in that the material-laden hot gas stream exhibits a temperature of at least 350 C.

4. A method according to claim 1, characterised in that the coarser and finer fractions of the material stream exhibit a grain size in the range from 50 mm or less.

5. A method according to claim 1, characterised in that the temperature drop of the material stream between entry into the separator and exit from the classifier is minimised.

6. A method according to claim 1, characterised in that the temperature of the coarser fraction of the material stream is at least 300 C. on exit from the classifier.

Description

(1) The invention is explained in greater detail with reference to the following description and drawings, in which:

(2) FIG. 1 is a schematic representation of an installation according to the invention for separating a material-laden hot gas stream and

(3) FIG. 2 is a schematic representation of an installation for processing oil shale material comprising an installation according to FIG. 1.

(4) The installation shown in FIG. 1 for separating a material-laden hot gas stream 1 consists substantially of a first separator 2 for separating the hot gas stream 1 into a gas stream 3 and a material stream 4 containing a coarser and a finer fraction, with an inlet 5 for the material-laden hot gas stream 1, an outlet 6 for the material stream 4 and an outlet 7 for the gas stream 3, a classifier 8 connected to the first separator 2, with a first inlet 9 for infeed of the material stream 4, a second inlet 10 for infeed of the gas stream 3 as a classifier gas stream, a first outlet 11 for the coarser fraction 4a of the material stream and a second outlet 12 for the gas stream 3 laden with the finer fraction 4b, a second separator 14, the inlet 15 of which is connected with the second outlet 12 of the classifier 8 and comprises a first outlet 16 for the finer fraction 4b of the material stream 4 and a second outlet for the gas stream 3.

(5) The outlet 7 for the gas stream 3 of the first separator 2 is connected both via a line 18 with the second inlet 10 of the classifier 8 and via a line 19 with the inlet 15 of the second separator 14. In order to be able to adjust subdivision of the gas stream 3 flowing to the classifier 8 or to the second separator 14, in the exemplary embodiment illustrated a control element 20 taking the form of a butterfly valve is provided in the line 19.

(6) Moreover, a further control element 21 is provided for dividing the material stream 4 between the first separator 2 and the first inlet 9 of the classifier 8. This control element 21 may take the form, for example, of an adjustable material sorting gate and adjusts the volume of the material stream 4 arriving at the classifier 8. One fraction 4 may be discharged at this point and fed to further post-treatment.

(7) The two separators 2, 14 preferably take the form of centrifugal separators, which each comprise a cylindrical upper part 2a, 14a and downwardly tapering conical lower part 2b, 14b. The inlets 5, 15 are each arranged tangentially on the cylindrical upper parts and the outlets 7, 17 for the gas stream 3 take the form of submerged tubes. The outlets 6, 16 for the material stream 4 or the finer fraction 4b are located at the lower end of the conical lower part 2b, 14b. The material-laden hot gas stream 1 or the gas stream 3 laden with the finer fraction 4b are thus introduced tangentially into the separator 2 or 14 respectively, wherein the material is carried away via the conical lower part and the gas stream via the submerged tube.

(8) The classifier 8 conveniently takes the form of a static classifier and in particular of a cross-flow classifier and comprises an obliquely oriented aeration floor 8a, the material stream 4 being loaded from above onto the aeration floor and sliding thereon downwards towards the first outlet 11. At the same time, the material stream 4 is exposed to the gas stream 3 flowing as a classifier gas stream transversely through the aeration floor 8a. In the process, the finer fraction 4b of the material stream 4 is discharged with the gas stream 3 via the second outlet 12, while the coarser fraction 4a is discharged via the first outlet 11.

(9) Cellular wheel sluices 22, 23 are preferably provided to regulate the volume of the material stream 4 to be fed to the classifier 8 and for gas-tight discharge of the finer fraction 4b from the installation.

(10) The hot gas stream 1 may moreover be fed via a riser pipe 24 to the first separator 2. The riser pipe 24 may in this case serve to heat the material entrained in the gas stream to temperatures of 300 C. to 1000 C. The material in the hot gas stream may exhibit a grain size in the range from 0 to 50 mm, preferably up to 20 mm.

(11) Depending on the setting of the volume of the gas stream 3 fed to the classifier 8 via the line 18 and the setting of the control element 21, the coarser fraction 4a may be adjusted purposefully with regard to quality and quantity. Separation in the first separator 2 and classification in the classifier 8 preferably proceed in such a way that the temperature drop in the material stream between entry into the first separator 2 and exit from the classifier 8 is minimised and is preferably less than 50 C. This is achieved in particular in that separation is a closed process and the material does not leave the hot zone. An attempt is additionally made to ensure that the temperature of the coarser fraction of the material stream is at least 300 C., preferably at least 600 C., on exit from the classifier.

(12) The above-described method and the associated installation are used according to the invention in processing oil shale material, in particular in the Galoter method, which is described in greater detail below with reference to FIG. 2.

(13) The same reference numerals denote the same components in FIGS. 1 and 2.

(14) FIG. 2 shows an installation for processing oil shale material 25, which is fed to a retort 26, where hydrocarbons 27 are expelled thermally from the oil shale material 25 in the form of vapour. The oil shale ash 28 arising during this process is heated up outside the retort together with a gas stream 3 in a riser pipe 24, optionally with infeed of combustion fuel.

(15) The resultant material-laden hot gas stream in the first separator 2, the classifier 8 and the second separator 14 is then separated in the manner described in FIG. 1 into the coarser fraction 4b, the finer fraction 4a and the gas stream 3, wherein the coarser fraction 4b is fed back to the retort, while the finer fraction is carried away, optionally together with a fraction of the material stream 4, and fed to a post-treatment, before the material is disposed of on a waste dump.