Plant and method for the thermal treatment of solids

Patent metadata

Field	Value
Publication number	US-2020190613-A1
Application number	US-202016798735-A
Country	US
Kind code	A1
Filing date	Feb 24, 2020
Priority date	Sep 4, 2017
Publication date	Jun 18, 2020
Grant date	—

Abstract

A method and its related plant for the thermal treatment of iron containing oxide, in which fine-grained solids are heated in a preheating calcining stage and are exposed to a reduction gas in a subsequent reduction stage. Off-gas from the reduction stage is guided through a separation device wherein the water originating from the reduction stage is separated. The off-gas from the preheating calcining stage is guided through a venturi scrubber and a packed bed section downstream of the venturi scrubber to condense water vapor.

First claim

1 .- 15 . (canceled)

16 . A method for the thermal treatment of iron containing oxide, in which fine-grained solids are heated in a preheating calcining stage and are exposed to a reduction gas in a subsequent reduction stage, wherein off-gas from the reduction stage is guided through a separation device, separating the water originating from the reduction stage, wherein off-gas from the preheating calcining stage is guided through a venturi scrubber and a packed bed section downstream of the venturi scrubber to condense water vapor, wherein the water separated in at least one separation device is recycled into a water treatment section, from which the recycled water is supplied to a water electrolysis plant and/or a steam reforming plant producing hydrogen, and that the produced hydrogen is supplied to the reduction stage as reductant and/or to the preheating calcining stage as fuel and/or to the gas heater as fuel and/or from which the recycled water is supplied to at least one separation device as process water, wherein the process water exchanges heat with the off-gas, is cooled in the water treatment section and is recirculated to the separation device.

17 . The method according to claim 16 , wherein the preheating calcining stage and/or the reduction stage comprises a fluidized bed reactor, preferably a circulating fluidized bed reactor.

18 . The method according to claim 16 , wherein the preheating calcining stage and/or the reduction stage comprises a circulating fluidized bed reactor.

19 . The method according to claim 16 , wherein the preheating stage and/or the reduction stage is heated with at least one gas heater, and that the off-gas from the at least one gas heater is guided through a separation device to condense water vapor.

20 . The method according to claim 16 , wherein the downstream of the reduction stage the reduced solids are cooled in a quench cool, preferably a vibratory cooling conveyor and that the off-gas from the quench cool is guided through a separation device to condense water vapor.

21 . The method according to claim 16 , wherein the quench cool is a vibratory cooling conveyor.

22 . The method according to claim 16 , wherein the hydrogen content in the reduction gas is at least 85 v/v.-% and/or the hydrogen content in a fuel gas used in the preheating stage 2 is at least 20 v/v.-%. and/or the hydrogen content in a fuel gas used in at least one gas heater is at least 20 v/v.-%.

23 . The method according to claim 16 , wherein the water treatment section encompasses removal of solids, removal of incondensable gases and indirect cooling.

24 . The method according to claim 16 , wherein the oxygen generated in the water electrolysis plant is supplied to the preheating stage and/or the gas heater for the combustion of fuel.

25 . A plant for the thermal treatment of iron containing oxide comprising a preheating calcining stage, for heating up fine-grained solids and a reduction stage, for reducing the heated solids by exposure to a reduction gas comprising hydrogen, wherein an off-gas outlet of the reduction stage is connected to a separation device to condense water vapor from the off-gas of the reduction stage, wherein an off-gas outlet of the preheating calcining stage is connected to a venturi scrubber and a packed bed section arranged downstream of the venturi scrubber to condense water vapor wherein a water outlet of at least one separation device is connected to a water treatment section for recycling the water, that the water treatment section is coupled to a water electrolysis plant and/or a steam reforming plant producing hydrogen as a reductant for the reduction stage and/or as a fuel for the preheating calcining stage and/or to the gas heater as fuel and/or that the water treatment section is coupled to at least one separation device to provide process water, which exchanges heat with the off-gas, is cooled in the water treatment section and is recirculated to the separation device.

26 . The plant according to claim 25 , wherein the water treatment section comprises a thickener with a filter press for the filtration of underflow slurry and/or a covered water surface of the thickener.

27 . The plant according to claim 25 , wherein the water treatment section comprises a warm water tank for chemical treatment.

28 . The plant according to claim 25 , wherein the water treatment section comprises an air fan cooler and/or a chiller for cooling the water.

29 . The plant according to claim 25 , wherein the water treatment section comprises a water filter and/or an ion exchange device.

Assignees

• Outotec Finland Oy

Inventors

• Ströder Michael
• Valery Roberto
• Lang Sebastian
• Rannantie Suvi
• Siauw Vincent
• Rimaszeki Gergö

Classifications

• Y02P10/134

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

• C21B2100/80

  Interaction of exhaust gases produced during the manufacture of iron or steel with other processes · CPC title

• C21B13/0046 Primary

  making metallised agglomerates or iron oxide · CPC title

• C21B13/0033

  In fluidised bed furnaces or apparatus containing a dispersion of the material · CPC title

• C21B2100/64

  Controlling the physical properties of the gas, e.g. pressure or temperature · CPC title