Direct reduction process for the production of direct-reduced iron with high purity methane

Patent metadata

Field	Value
Publication number	US-2019323098-A1
Application number	US-201716471115-A
Country	US
Kind code	A1
Filing date	Dec 14, 2017
Priority date	Dec 22, 2016
Publication date	Oct 24, 2019
Grant date	—

Abstract

Systems and processes to produce direct reduced iron with a gaseous reducing stream having less than 10 mol. % nitrogen (N 2 ) and greater than 80 mol. % methane (CH 4 ) are described. A process includes separating N 2 from a gaseous stream to produce the reducing stream and contacting the reducing stream with iron ore under conditions sufficient to form direct-reduced iron. The reduction in the N 2 content of the reducing stream improves the overall steel producing capacity by at least 2%.

First claim

1 . A direct reduction process for producing direct-reduced iron, the process comprising:
(a) subjecting a gaseous stream comprising methane (CH 4 ) and nitrogen (N 2 ) to conditions sufficient to separate N 2 from the gaseous stream and form a gaseous reducing stream comprising less than 10 mol. % N 2 and greater than 80 mol. % CH 4 ; and (b) contacting the gaseous reducing stream with iron ore under conditions sufficient to form direct-reduced iron.

2 . The direct reduction process of claim 1 , further comprising capturing energy from step (b) and using the energy in step (a).

3 . The direct reduction process of claim 1 , wherein conditions sufficient to form direct-reduced iron comprise:
(i) heating the gaseous reducing stream; (ii) contacting the heated gaseous reducing stream with iron ore to form direct-reduced iron; and (iii) capturing energy from step (i) and/or step (ii) and providing the captured energy to step (a).

4 . The direct reduction process of claim 3 , wherein substantially all of the energy required for the separation conditions of step (a) is obtained from the captured energy.

5 . The direct reduction process of claim 1 , wherein the gaseous reducing stream comprises 0 to 10 mol. % N 2 , 2 to 6 mol. % N 2 , or 4 to 6 mol. % Na.

6 . The direct reduction process of claim 1 , wherein the gaseous reducing stream comprises 85 to 99 mol. % CH4, 87 to 98 mol. % CH 4 , or 90 to 95 mol. % CH 4 .

7 . The direct reduction process of claim 1 , further comprising producing iron steel from the direct-reduced iron.

8 . The direct reduction process of claim 7 , wherein separation of N 2 in step (a) increases iron steel production capacity by at least 2%, at least 5%, at least 9%, or at least 15%.

9 . The direct reduction process of claim 1 , wherein the separation conditions comprise flowing the gaseous stream through a membrane system to produce the gaseous reducing stream and a N 2 -containing stream.

10 . The direct reduction process of any claim 1 , wherein the separation conditions comprise cryogenically distilling the gaseous stream comprising CH 4 and N 2 to produce the gaseous reducing stream and a N 2 -containing stream.

11 . The direct reduction process of claim 9 , wherein the N 2 -containing stream comprises N 2 and CH 4 .

12 . The direct reduction process of claim 11 , further comprising generating heat from the N 2 -containing stream by combusting the N 2 -containing stream, and providing the heat to one or more steel production processes.

13 . The direct reduction process of claim 1 , wherein the gaseous reducing stream of step (a) is heated in the presence of an oxidant and then contacted with the iron ore in step (b).

14 . The direct reduction process of claim 1 , wherein the gaseous stream is natural gas.

15 . The direct reduction process of claim 1 , wherein the gaseous stream comprises 70 to 88 mol. % CH 4 , 1 to 5 mol. % ethane, 1 to 5 mol. % propane, 15 to 20 mol % nitrogen, 0.1 to 1 mol. % with the balance being carbon monoxide and oxygen.

16 . The direct reduction process of claim 10 , wherein the N 2 -containing stream comprises N 2 and CH 4 .

17 . The direct reduction process of claim 3 , further comprising producing iron steel from the direct-reduced iron.

18 . The direct reduction process of claim 4 , further comprising producing iron steel from the direct-reduced iron.

19 . The direct reduction process of claim 5 , further comprising producing iron steel from the direct-reduced iron.

20 . The direct reduction process of claim 6 , further comprising producing iron steel from the direct-reduced iron.

Assignees

• Sabic Global Technologies Bv

Inventors

• Handagama Nareshkumar Bernard
• Liu Zheng

Classifications

• F27D7/06

  Forming or maintaining special atmospheres or vacuum within heating chambers (supplying steam, vapour, gases or liquids F27D7/02) · CPC title

• B01D53/22

  by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) · CPC title

• B01D2257/102

  Nitrogen · CPC title

• C21B13/0073 Primary

  Selection or treatment of the reducing gases · CPC title

• B01D2256/245

  Methane · CPC title