Method for operating a blast furnace plant

Patent metadata

Field	Value
Publication number	US-2024077255-A1
Application number	US-202218271927-A
Country	US
Kind code	A1
Filing date	Jan 20, 2022
Priority date	Jan 20, 2021
Publication date	Mar 7, 2024
Grant date	—

Abstract

A method for operating a blast furnace plant that includes a blast furnace, at least one material hopper for charging raw materials to the blast furnace, having a upper seal valve and a lower seal valve, and at least one hot stove that produces hot blast for the blast furnace, the method including at least one charging cycle with the following steps: opening the upper seal valve, introducing raw materials into the material hopper, closing the upper seal valve, pressure equalization of the material hopper with blast furnace top pressure, and opening the lower seal valve to discharge raw materials into the blast furnace, wherein, in order to provide a cost-effective way to minimize the explosion danger during operation of a top charging system, an offgas from the at least one hot stove is transferred by a transfer system to the at least one material hopper and, before the lower seal valve is opened, the offgas is injected into the material hopper.

First claim

1 . A method for operating a blast furnace plant that comprises a blast furnace, at least one material hopper for charging raw materials to the blast furnace, having an upper seal valve and a lower seal valve, and at least one hot stove that produces hot blast for the blast furnace, the method comprising at least one charging cycle with the following steps:
opening the upper seal valve, introducing raw materials into the material hopper, closing the upper seal valve, pressure equalization of the material hopper with blast furnace top pressure, and opening the lower seal valve to discharge the raw materials into the blast furnace,
wherein an offgas from the at least one hot stove is transferred by a transfer system to the at least one material hopper and the offgas is injected into the material hopper and the material hopper is pressurized to blast furnace top pressure before the lower seal valve is opened and the raw materials are discharged into the blast furnace.

2 . The method according to claim 1 , wherein the offgas is injected to constitute at least 70% v/v of a gas inside the material hopper when the lower seal valve is opened.

3 . The method according to claim 1 , wherein the offgas is injected so that the gas inside the material hopper has an O 2 concentration of less than 4.5% v/v when the lower seal valve is opened.

4 . The method according to claim 1 , wherein after opening the lower seal valve, a gas inside the material hopper at least partially mixes with a blast furnace gas from the blast furnace having an H 2 concentration of at least 5% v/v.

5 . The method according to claim 1 , wherein the offgas has an O 2 concentration of less than 2% v/v.

6 . The method according to claim 1 , wherein after closing the upper seal valve and before opening the lower seal valve, an overpressure is generated inside the material hopper.

7 . The method according to claim 1 , wherein the offgas is at least partially injected before the raw materials are introduced into the material hopper.

8 . The method according to claim 1 , wherein the offgas is at least partially injected between the lower seal valve and a lower material gate.

9 . The method according to claim 1 , wherein the offgas is at least partially injected while the raw materials are introduced into the material hopper.

10 . The method according to claim 1 , wherein each hot stove alternatingly undergoes a heating phase, in which it is heated by a combustion that produces the offgas, and a blowing phase, in which it produces hot blast, and offgas is collected from the hot stove after the start of a heating phase and before the start of the following blowing phase.

11 . The method according to claim 1 , wherein the transfer system comprises a collecting pipe for each hot stove, a discharge pipe for each material hopper and an intermediate portion connecting each collecting pipe to each discharge pipe.

12 . The method according to claim 1 , wherein the offgas collected from a hot stove is cooled by a cooling device before it is injected into the material hopper.

13 . The method according to claim 1 , wherein the offgas is propelled through the transfer system by a blower unit.

14 . The method according to claim 1 , wherein the offgas is directed selectively to at least one of a plurality of material hoppers by a distribution valve unit.

15 . A blast furnace plant, comprising:
a blast furnace, at least one material hopper for charging raw materials to the blast furnace, having an upper seal valve and a lower seal valve, at least one hot stove adapted to produce hot blast for the blast furnace, and a transfer system adapted to transfer an offgas from the at least one hot stove to the at least one material hopper, wherein the blast furnace plant is adapted to inject the offgas into the material hopper and perform at least one charging cycle as defined in claim 1 .

Assignees

• Wurth Paul Sa

Inventors

• Tockert Paul
• Franziskus Lutwin
• Ries Roger
• Schon Marc
• Schweitzer Marc

Classifications

• F27D17/13

  using regenerative heat exchangers · CPC title

• F27D17/30

  Arrangements for extraction or collection of waste gases; Hoods therefor · CPC title

• F27D17/10

  Arrangements for using waste heat · CPC title

• F27B1/20 Primary

  Arrangements of devices for charging · CPC title

• C21B7/10

  Cooling; Devices therefor · CPC title