Method for treating pourable, inorganic grain, and rotary tube suitable for performing the method

Patent metadata

Field	Value
Publication number	US-11674755-B2
Application number	US-202016872775-A
Country	US
Kind code	B2
Filing date	May 12, 2020
Priority date	May 17, 2019
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

In a known method for treating pourable, inorganic grain, a heated rotary tube is used that rotates about an axis of rotation and surrounds a treatment chamber that is divided into a plurality of treatment zones by means of separating elements. The grain is supplied to the treatment chamber at a grain inlet side and is transported, in a grain transport direction, to a grain outlet side and is exposed to a treatment gas in the process. In order, proceeding herefrom, to allow for reliable and reproducible thermal treatment of pourable inorganic grain, in particular SiO2 grain in the rotary kiln, in a manner having low and effective consumption of treatment gas, it is proposed for spent treatment gas to be suctioned out of a reaction zone of the treatment chamber, by a gas manifold that rotates about the longitudinal axis thereof.

First claim

The invention claimed is:

1. A method for treating pourable, inorganic grain in a heated rotary tube that rotates about an axis of rotation and surrounds a treatment chamber that is divided into a plurality of treatment zones (A; B; C; D) by separating elements, the plurality of treatment zones including at least one reaction zone (C), the method comprising:
supplying the grain to the treatment chamber at a grain inlet side;
transporting the grain, in a grain transport direction, to a grain outlet side; and
exposing the grain to a treatment gas;
wherein spent treatment gas is suctioned out of the reaction zone (C) by a gas manifold, which rotates about the longitudinal axis thereof;
wherein the spent treatment gas is suctioned out of the gas manifold by a rotationally fixed suction pipe, which protrudes into the gas manifold;
wherein the treatment gas is introduced into the gas manifold at the grain outlet side and is conveyed from one chamber (A; B; C; D) to the next chamber counter to the grain transport direction and emerges from the gas manifold, into the reaction zone (C), through at least one gas outlet wall opening, and spent treatment gas enters the gas manifold again, from the reaction zone (C), through at least one gas inlet wall opening; and
wherein between the gas outlet wall opening and the gas inlet wall opening, the gas manifold is closed.

2. The method according to claim 1 , wherein the gas manifold is rotationally fixed to at least one separating element, and in that the separating elements each comprise a transfer opening for allowing grain to pass through from one zone (A; B; C; D) to the next zone.

3. The method according to claim 2 , wherein the separating elements are equipped with a grain baffle that plunges into the grain as a result of the rotation of the rotary tube and transports entrained grain to the transfer opening in the process.

4. The method according to claim 3 , wherein a front separating element is arranged downstream of the grain inlet side and a rear separating element is arranged upstream of the grain outlet side, viewed in the grain transport direction, and in that the front separating element and/or the rear separating element are made from opaque quartz glass.

5. The method according to claim 4 , wherein the rotary tube comprises unheated end-face end portions, and in that the front separating element and the rear separating element are each arranged in an unheated end-face end portion.

6. The method according to claim 2 , wherein a front separating element is arranged downstream of the grain inlet side and a rear separating element is arranged upstream of the grain outlet side, viewed in the grain transport direction, and in that the front separating element and/or the rear separating element are made from opaque quartz glass.

7. The method according to claim 6 , wherein the rotary tube comprises unheated end-face end portions, and in that the front separating element and the rear separating element are each arranged in an unheated end-face end portion.

8. The method according to claim 1 , wherein the gas manifold comprises a length portion that protrudes out of the rotary tube at the grain outlet side, and in that at least the length portion is made of opaque quartz glass.

9. A rotary tube for treating pourable, inorganic grain, which tube is rotatable about an axis of rotation that is inclined relative to the horizontal, and which tube surrounds a treatment chamber for receiving the grain, which chamber is divided into a plurality of treatment zones (A; B; C; D) by separating elements, the plurality of treatment zones including at least one reaction zone (C), the rotary tube comprising:
a grain inlet side for introducing the grain into the treatment chamber;
a grain outlet side for discharging the grain from the treatment chamber;
a gas inlet for introducing a treatment gas into the reaction zone (C); and
a gas outlet for removing spent treatment gas from the treatment chamber;
wherein the gas outlet comprises a gas manifold that rotates about the longitudinal axis thereof; and
wherein the gas outlet comprises a suction pipe that protrudes into the gas manifold or adjoins the gas manifold without direct contact;
wherein the gas manifold has at least one gas outlet wall opening and at least one gas inlet wall opening; and
wherein between the gas outlet wall opening and the gas inlet wall opening, the gas manifold is closed.

10. The rotary tube according to claim 9 , wherein the gas manifold comprises a tube longitudinal axis that extends coaxially to the axis of rotation of the rotary tube.

11. The rotary tube according to claim 9 , wherein the gas inlet is provided at a gas inlet end of the gas manifold which is located at the grain outlet end of the rotary tube.

12. The rotary tube according to claim 11 , wherein a front separating element is arranged downstream of the grain inlet side and a rear separating element is arranged upstream of the grain outlet side, viewed in the grain transport direction, and in that the front separating element and/or the rear separating element are made from opaque quartz glass.

13. The rotary tube according to claim 9 , wherein the gas manifold is rotationally fixed to at least one separating element, and in that the separating elements each comprise a transfer opening for allowing grain to pass through and through which opening the gas manifold extends, and in that the separating elements are equipped with a grain baffle which is designed to plunge into the grain as a result of the rotation of the rotary tube and to transport entrained grain to the transfer opening in the process.

14. The rotary tube according to claim 13 , wherein a front separating element is arranged downstream of the grain inlet side and a rear separating element is arranged upstream of the grain outlet side, viewed in the grain transport direction, and in that the front separating element and/or the rear separating element are made from opaque quartz glass.

15. The rotary tube of claim 14 , wherein the rotary tube comprises unheated end-face end portions, and in that the front separating element and the rear separating element are each arranged in an unheated end-face end portion.

Assignees

• Heraeus Quarzglas

Inventors

• Söhn Matthias

Classifications

• B01J8/087

  Heating or cooling the reactor · CPC title

• B01J2219/187

  inclined at an angle to the horizontal or to the vertical plane · CPC title

• F27D3/0033

  charging of particulate material · CPC title

• F27B2007/022

  the drum having a non-uniform section along its length · CPC title

• F27B7/06 Primary

  adapted for treating the charge in vacuum or special atmosphere · CPC title