Method for controlling the suspension in a suspension smelting furnace, a suspension smelting furnace, and a concentrate burner

Patent metadata

Field	Value
Publication number	US-2017248368-A1
Application number	US-201715593593-A
Country	US
Kind code	A1
Filing date	May 12, 2017
Priority date	Nov 29, 2011
Publication date	Aug 31, 2017
Grant date	—

Abstract

The invention relates to a method for controlling suspension in a suspension smelting furnace, to a suspension smelting furnace, and to a concentrate burner. The method comprises feeding additionally to pulverous solid matter and additionally to reaction gas reducing agent into the suspension smelting furnace, wherein reducing agent is fed in the form of a concentrated stream of reducing agent through the suspension in the reaction shaft onto the surface of the melt to form a reducing zone containing reducing agent within the collection zone of the melt.

First claim

1 . A suspension smelting furnace for suspension smelting of pulverous solid matter, wherein the suspension smelting furnace comprises
a reaction shaft having a top and a lower end, a concentrate burner that comprises a pulverous solid matter supply device for feeding pulverous solid matter and that comprises a gas supply device for feeding reaction gas into the reaction shaft to produce a suspension of pulverous solid matter and reaction gas in the reaction shaft, wherein the concentrate burner is located at the top of the reaction shaft, a lower furnace for collecting suspension in the lower furnace to form a melt having a surface, wherein the lower end of the reaction shaft ends in the lower furnace and wherein, when the suspension smelting furnace is in use, suspension that is produced in the reaction shaft and that lands on the surface of the melt in the lower furnace is configured to create a collection zone at the surface of the melt in the lower furnace, and a reducing agent feeding means for feeding additionally to pulverous solid matter and additionally to reaction gas reducing agent into the suspension smelting furnace, wherein the reducing agent feeding means is configured for feeding, when the suspension smelting furnace is in use, reducing agent in the form of a concentrated stream of reducing agent through the suspension that is produced in the reaction shaft onto the surface of the melt in the lower furnace to form a reducing zone containing reducing agent in the collection zone of the melt in the lower furnace, wherein the reducing agent feeding means is configured to feed reducing agent at an initial velocity that is at least the feeding velocity of the reaction gas, wherein the concentrate burner being configured to feed pulverous solid matter and reaction gas into the reaction shaft so that suspension produced by pulverous solid matter and reaction gas forms a suspension jet in the suspension shaft, wherein the suspension jet widens in the reaction shaft in the direction of the lower furnace and wherein the suspension jet has an imaginary vertical central axis, and wherein the reducing agent feeding means being configured to feed the concentrated stream of reducing agent essentially in the direction of the imaginary vertical central axis of the suspension jet and in the vicinity to the imaginary vertical central axis of the suspension jet to prevent reducing agent of the concentrated stream of reducing agent from reacting with reaction gas prior landing on the surface of the melt.

2 . The suspension smelting furnace according to claim 1 , wherein the reducing agent feeding means being configured to feed the concentrated stream of reducing agent from the inside the lower furnace of the suspension smelting furnace.

3 . The suspension smelting furnace according to claim 1 , wherein the reducing agent feeding means being configured to feed the concentrated stream of reducing agent from the inside the reaction shaft of the suspension smelting furnace.

4 . The suspension smelting furnace according to claim 1 , wherein the reducing agent feeding means being configured to feed the concentrated stream of reducing agent from the top of the reaction shaft of the suspension smelting furnace inside the reaction shaft of the suspension smelting furnace.

5 . The suspension smelting furnace according to claim 1 , wherein the concentrate burner being provided with a reducing agent feeding means configured to feed the concentrated stream of reducing agent.

6 . The suspension smelting furnace according to claim 1 , wherein the concentrate burner comprising
a pulverous solid matter supply device comprising a feeder pipe for feeding pulverous solid matter into the reaction shaft, wherein the feeder pipe has an orifice that opens to the reaction shaft; a dispersing device, which is arranged concentrically inside the feeder pipe and which extends to a distance beyond the orifice of the feeder pipe into the reaction shaft and which comprises dispersion gas openings for directing dispersion gas around the dispersing device and to pulverous solid matter that flows around the dispersing device; and a gas supply device for feeding reaction gas into the reaction shaft, wherein the gas supply device opening to the reaction shaft through an annular discharge orifice that concentrically surrounds the feeder pipe for mixing reaction gas that discharges from the annular discharge orifice with pulverous solid matter, which discharges from the orifice of the feeder pipe and which is directed to the side by means of dispersion gas to produce suspension of pulverous solid matter and reaction gas in the reaction shaft.

7 . The suspension smelting furnace according to claim 6 , wherein the concentrate burner comprising a reducing agent feeding means in the form of a central lance that is arranged inside the dispersing device of the concentrate burner, wherein the central lance comprising a discharge orifice that opens to the reaction shaft.

8 . The suspension smelting furnace according to claim 1 , wherein the reducing agent feeding means being configured to feed a concentrated stream of reducing agent that contains at least one of carbon, sulphide such as coke, coke powder, pulverized biomass, pulverized charcoal, the same pulverous solid matter that is fed by means of the pulverous solid matter supply device of the concentrate burner, ground electronic scrap and circuit board chaff.

9 . The suspension smelting furnace according to claim 1 , wherein the reducing agent feeding means is configured to feed reducing agent at an initial velocity that is at least twice the feeding velocity of the reaction gas.

10 . The suspension smelting furnace according to claim 1 , wherein the gas supply device being configured to feed as reaction gas oxygen enriched gas that has an oxygen content between about 50 and about 100%.

11 . The suspension smelting furnace according to claim 1 , including controlling means configured to control the amount of fed reaction gas to the amount of fed reducing agent to form sub-stoichiometric conditions in the middle of the suspension of the suspension smelting furnace.

12 . The suspension smelting furnace according to claim 1 , including controlling means configured to control the amount of fed reaction gas to the amount of fed reducing agent to form stoichiometric or over-stoichiometric conditions in the middle of the suspension of the suspension smelting furnace.

Assignees

• Outotec Finland Oy

Inventors

• Lahtinen Markku
• Pesonen Lauri P
• Ahokainen Tapio
• Bjorklund Peter

Classifications

• F27D2019/0075

  Regulation of the charge quantity · CPC title

• F27D19/00 Primary

  Arrangements of controlling devices · CPC title

• F27D2019/0068

  Regulation involving a measured inflow of a particular gas in the enclosure · CPC title

• F27B1/20

  Arrangements of devices for charging · CPC title

• F27B1/26

  Arrangements of controlling devices · CPC title