APPARATUS AND PROCESS FOR THERMAL TREATMENT OF MINERAL SOLIDS

Abstract

An apparatus for thermally treating mineral solids includes a preheater, a separating apparatus arranged at an outlet of an entrained flow reactor, and a thermal treatment zone at an outlet of a gas stream of the separating apparatus, with an outlet of the treatment zone being connected to an inlet of the preheater for the gas stream. A process may involve preheating a mineral material, thermally treating the mineral material in an entrained flow reactor in a reducing atmosphere for reducing coloring metal compounds, separating a solid/gas mixture from the entrained flow reactor in a separating apparatus, oxidizing reducing constituents of a gas from the separating apparatus in a thermal treatment zone between the separating apparatus and the preheater via supplied oxygen, and supplying gas emerging from the thermal treatment zone to the preheater and thereby utilizing thermal energy recovered in the thermal treatment zone by transfer to mineral material

Claims

1.-12. (canceled)

13. An apparatus that is configured to thermally treat mineral solids, the apparatus comprising: a preheater; an entrained flow reactor comprising a reducing agent supply line; a separating apparatus disposed at an outlet of the entrained flow reactor; and a thermal treatment zone disposed at an outlet of a gas stream of the separating apparatus, wherein the thermal treatment zone comprises a second supply apparatus for oxygen, wherein the thermal treatment zone is configured for reacting a reducing agent supplied by the reducing agent supply line with the oxygen, wherein an outlet of the thermal treatment zone is connected to an inlet of the preheater for a gas stream.

14. The apparatus of claim 13 wherein the reducing agent supply line is a supply apparatus for the reducing agent.

15. The apparatus of claim 13 wherein the reducing agent supply line is a combustion apparatus that supplies more fuel than there is oxygen present, the combustion apparatus being configured to generate reducing constituents.

16. The apparatus of claim 13 comprising a transfer apparatus for the mineral solids, which are heated in the preheater, for transfer from the preheater to the entrained flow reactor.

17. The apparatus of claim 13 wherein the thermal treatment zone is cylindrical.

18. The apparatus of claim 13 wherein the thermal treatment zone is tubular and extends vertically above the separating apparatus.

19. The apparatus of claim 13 wherein the thermal treatment zone includes a first supply apparatus for a fuel.

20. The apparatus of claim 13 wherein the preheater is a cyclone preheater.

21. The apparatus of claim 13 wherein the preheater is a two-stage cyclone preheater.

22. A process for thermally treating mineral material that comprises iron compounds and/or chromium compounds, the process comprising: preheating a mineral material in a preheater; transferring the mineral material that is heated in the preheater to an entrained flow reactor; thermally treating the mineral material in the entrained flow reactor in a reducing atmosphere for reducing coloring metal compounds during the thermal treatment; separating a solid/gas mixture coming from the entrained flow reactor in a separating apparatus; oxidizing reducing constituents of a gas coming from the separating apparatus in a thermal treatment zone between an outlet of a gas stream of the separating apparatus and an inlet of the preheater for the gas stream by way of supplied oxygen; and supplying the gas emerging from the thermal treatment zone to the preheater and thereby utilizing thermal energy recovered in the thermal treatment zone by transfer to the mineral material.

23. The process of claim 22 wherein the oxidizing occurs at a temperature of 700° C. to 1000° C. and over a period of 1 s to 10 s.

24. The process of claim 22 comprising supplying a fuel to the gas in the oxidizing step.

25. The process of claim 22 comprising guiding a flow of the mineral material around the thermal treatment zone.

Description

[0053] The apparatus of the invention is elucidated in more detail below, using an exemplary embodiment as represented in the drawings.

[0054] FIG. 1 schematic view of the apparatus

[0055] In FIG. 1 the apparatus is shown illustratively. The apparatus comprises an entrained flow reactor 10, a separating apparatus 20, a thermal treatment zone 30, a first preheating cyclone 40, a second preheating cyclone 50, and a cooler 60.

[0056] At the start the raw material 100 is added. This material may, for example, have been dried and ground beforehand, before being introduced here into the apparatus. The raw material 100 is mixed with the slightly cooled gas stream 220, which comes from the first preheating cyclone 40. In the first preheating stage 110, the gas stream transfers the heat to the raw material. In the second preheating cyclone 50, the gas stream is separated from the solid. The aforesaid raw material 120 is mixed subsequently with the combustion gases 210 coming from the thermal treatment zone 30. In the second preheating stage 130 the gas stream gives up its heat to the raw material.

[0057] Subsequently, in the first preheating cyclone 40, the solid is again separated from the gas stream. The heated raw material 140 is supplied to the entrained flow reactor 10. In the entrained flow reactor 10 the raw material is converted thermally to give the product, and the product undergoes color optimization. For the color optimization, for example, carbon, hydrogen or natural gas is supplied via the reducing agent supply line 300. Subsequently in the separating apparatus 20, which is likewise designed as a cyclone, the solid is separated from the gas stream. The hot product 150 is passed to the cooler 60, where it is cooled and can be withdrawn as product 160. Cooler 60 may for example have a multistage design, more particularly a two-stage design; for example, the cooler may be or may comprise a fluidized bed cooler, a moving bed cooler, a cooling coil, a cyclone cooler, a fluid-bed cooler, or a drum cooler.

[0058] The gas stream 200 is supplied to the entrained flow reactor 10. A burner here may ensure the necessary temperature, for example. This burner may be operated, for example, so that it generates carbon monoxide (CO), for example, and so introduces reducing constituents into the gas stream. Hydrocarbons or hydrogen, for example, in the form of unreacted combustion gases, for example, may also be introduced in this way. Alternatively or additionally a further burner may be arranged. The gas stream carries the solid through the entrained flow reactor 10 and is separated from the solid in the separating apparatus 20. From the separating apparatus 20, the gas stream, in the example shown, enters directly and immediately into the thermal treatment zone 30, which is arranged vertically above the separating apparatus 20. In the example shown, the thermal treatment zone 30 comprises a first supply line for fuel 310 and a second supply line for oxygen 320. As a result there is complete combustion of the reducing constituents contained in the gas stream—for example, hydrogen (H.sub.2), carbon monoxide (CO) or hydrocarbons. At the same time the gas stream is preferably heated by the combustion energy liberated, or heat losses, owing for example to emission to the environment or to the supplying of further components, especially cold components, air for example, are compensated. The gas stream emerges as hot combustion gas 210 and is mixed with the preheated raw material 120 and passed to the second preheating stage 130. The gas stream is subsequently separated from solid in the first preheating cyclone 40, and the slightly cooled gas stream 220 is mixed with the raw material 100 and passed into the first preheating stage 110, in which the residual heat of the gas stream is transferred to the solid. The solid is subsequently removed from the gas stream in the second preheating cyclone 50. Gas stream 230 emerges, cooled, from the second preheating cyclone 50.

REFERENCE SYMBOLS

[0059] 10 Entrained flow reactor [0060] 20 Separating apparatus [0061] 30 Thermal treatment zone [0062] 40 First preheating cyclone [0063] 50 Second preheating cyclone [0064] 60 Cooler [0065] 100 Raw material [0066] 110 First preheating stage [0067] 120 Preheated raw material [0068] 130 Second preheating stage [0069] 140 Heated raw material [0070] 150 Hot product [0071] 160 Product [0072] 200 Gas stream [0073] 210 Combustion gases [0074] 220 Slightly cooled gas stream [0075] 230 Cooled gas stream [0076] 300 Reducing agent supply line [0077] 310 Fuel [0078] 320 Oxygen