Process and apparatus for direct reduction with electrically heated-up reduction gas

Patent metadata

Field	Value
Publication number	US-2022074006-A1
Application number	US-201917414368-A
Country	US
Kind code	A1
Filing date	Dec 16, 2019
Priority date	Dec 17, 2018
Publication date	Mar 10, 2022
Grant date	—

Abstract

Process for the direct reduction of metal oxides ( 2 ) using a reduction gas, which is based on at least one precursor gas, wherein at least one precursor gas ( 15, 22 ) is based on reformer gas obtained by catalytic reforming of hydrocarbon-containing gas ( 4 ) in a reformer ( 3 ), and in the preparation of the reduction gas at least one precursor gas based on reformer gas is heated up by means of electrical energy. An apparatus for the direct reduction ( 1 ) of metal oxides ( 2 ) by means of a reduction gas comprises a catalytic reformer ( 3 ) for producing a reformer gas, a reformer gas line ( 5 ) for removing reformer gas from the catalytic reformer ( 3 ), a reduction unit ( 9 ), a reduction gas line ( 8 ) for introducing reduction gas into the reduction unit ( 9 ), and at least one precursor gas line ( 6 ), wherein at least one precursor gas line extending from the reformer gas line comprises an electrical gas heating device ( 7, 10, 17 ), and at least one precursor gas line ( 6 ) extends from the reformer gas line ( 5 ), and each precursor gas line ( 6 ) opens out into the reduction gas line ( 8 ).

First claim

1 . A method of direct reduction of metal oxides using a reduction gas based on at least one precursor gas,
wherein the at least one precursor gas is based on reformer gas obtained by catalytic reforming of hydrocarbonaceous gas in a reformer, preparation of the reduction gas involves heating the at least one precursor gas based on reformer gas, and optionally additionally also heating one or more further precursor gases, by means of electrical energy, wherein the one or more further precursor gases optionally comprises the at least one precursor gas or another precursor gas, wherein at least a portion of the electrical energy is introduced by means of plasma.

2 . The method as claimed in claim 1 , wherein the at least one precursor gas based on the reformer gas is heated by the electrical energy to a temperature within a range of up to 200° C. above an exit temperature from the reformer.

3 . The method as claimed in claim 2 , wherein the at least one precursor gas envisaged for electrical heating, prior to the heating by means of the electrical energy, is already heated in another way to at least 700° C.

4 . The method as claimed in claim 3 , wherein the at least one precursor gas, which is envisaged for the electrical heating, by means of the electrical energy to more than 800° C.

5 . The method as claimed in claim 1 , wherein on introduction of the reduction gas into a reduction unit containing the metal oxides to be reduced, the temperature of the reduction gas is in the range of 800° C. to 1100° C.

6 . The method as claimed in claim 1 , further comprising adding hydrocarbonaceous additional gas to the further precursor gas which is heated by means of electrical energy.

7 . The method as claimed in claim 6 , further comprising reforming at least a portion of the hydrocarbonaceous additional gas in situ before the reduction gas is introduced into a reduction unit containing the metal oxides.

8 . (canceled)

9 . The method as claimed in claim 1 , further comprising directly reducing metal oxides using at least one additional reduction gas.

10 . An apparatus for directly reducing metal oxides by means of a reduction gas, the apparatus comprising:
a catalytic reformer for producing a reformer gas, a reformer gas conduit for discharging of the reformer gas from the catalytic reformer, a reduction unit, a reduction gas conduit for introducing reduction gas into the reduction unit, at least one precursor gas conduit, comprising an electrical gas heating apparatus, and wherein the at least one precursor gas conduit proceeding from the reformer gas conduit comprises an electrical gas heating apparatus,
and
wherein each precursor gas conduit opens into the reduction gas conduit,

and
wherein the electrical gas heating apparatus comprises at least two plasma burners.

11 . The apparatus as claimed in claim 10 , wherein the apparatus for direct reduction of metal oxides comprises at least one additional reduction gas conduit for introduction of additional reduction gas into the reduction unit.

12 . The apparatus as claimed in claim 10 , further comprising the electrical gas heating apparatus comprises at least one heating chamber having at least one of the plasma burner, at least one exit opening for exit of heated gas, and at least one entry opening for entry of precursor gas, and having at least one longitudinal heating chamber wall extending longitudinally when viewed from the entry opening toward the exit opening, wherein the plasma burner is disposed in a middle of the heating chamber, and wherein the entry opening is disposed between the plasma burner and a longitudinal heating chamber wall.

13 . The apparatus as claimed in claim 10 , further comprising the electrical gas heating apparatus comprises at least one heating chamber having at least one of the plasma burners, at least one exit opening for exit of heated gas, and at least one entry opening for entry of precursor gas, and at least one longitudinal heating chamber wall extending longitudinally when viewed from the entry opening toward the exit opening, wherein the entry opening is disposed and the heating chamber is shaped such that an introduced stream of the precursor gas flows from the entry opening to the exit opening in spiral form around the plasma burner between the plasma burner and the longitudinal heating chamber wall.

14 . The apparatus as claimed in claim 13 , wherein the entry opening is in an unsymmetric arrangement relative to the longitudinal axis of the heating chamber, and the entry opening is capable of guiding precursor gas into the heating chamber tangentially to the longitudinal heating chamber wall.

15 . The apparatus as claimed in claim 13 , wherein the hydraulic diameter of the entry opening is in the range from 25% to 75% of the hydraulic heating chamber diameter.

16 . The apparatus as claimed in claim 13 , wherein the heating chamber comprises a cylindrical entry section with the entry opening and a conical exit section with the exit opening, and the hydraulic diameter of the entry opening is in the range from 25% to 75% of the diameter of the entry section.

17 . The apparatus as claimed in claim 13 , wherein the heating chamber comprises a cylindrical entry section with the entry opening and a conical exit section with the exit opening, wherein the ratio of a height of the entry section to the diameter of the entry section is in the range from 1 to 10.

18 . The apparatus as claimed in claim 13 , wherein the heating chamber comprises a cylindrical entry section with the entry opening and a conical exit section with the exit opening, wherein the angle of the lateral heating chamber wall of the exit section to the longitudinal axis is in the range of 5°-45°.

19 . The apparatus as claimed in claim 10 , wherein the gas heating apparatus comprises at least one heating chamber in which there are multiple plasma burners.

Assignees

• Primetals Technologies Austria GmbH

Inventors

• Hauzenberger Franz
• Millner Robert
• Ofner Hanspeter
• Rein Norbert
• Rosenfellner Gerald
• Wurm Johann

Classifications

• C21B13/0073 Primary

  Selection or treatment of the reducing gases · CPC title

• C21B13/12

  in electric furnaces · CPC title

• Y02P10/134

  by avoiding CO2, e.g. using hydrogen · CPC title

• C21B2100/22

  by reforming · CPC title

• Y02P10/143

  of methane [CH4] · CPC title