Method and plant for the heat treatment of solids containing iron oxide using a fluidized bed reactor

A fluidized bed reactor, iron oxide-containing technology, used in chemical instruments and methods, fluidized bed furnaces, chemical/physical processes, etc., can solve heat and mass transfer moderation, internal combustion is difficult to control, preheating solids Difficulty integrating suspension heat exchangers, etc.

Active Publication Date: 2006-04-05
METSO OUTOTEC (FINLAND) OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the energy utilization in the calcination step obtained when using a fixed fluidized bed needs to be improved
This is due to the fact that internal combustion is difficult to control due to relatively moderate heat and mass transfer due to low fluidization
In addition, preheating solids is difficult to integrate in suspension heat exchangers because the dust-laden gas is not allowed to enter the fluidization nozzles of the fixed fluidized bed
On the other hand, circulating fluidized bed has better mass and heat transfer conditions because of higher degree of fluidization, and can integrate suspension heat exchanger, but its solid residence time is limited due to higher degree of fluidization

Method used

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  • Method and plant for the heat treatment of solids containing iron oxide using a fluidized bed reactor
  • Method and plant for the heat treatment of solids containing iron oxide using a fluidized bed reactor
  • Method and plant for the heat treatment of solids containing iron oxide using a fluidized bed reactor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] Embodiment 1 (heat treatment laterite type nickel ore)

[0069] In the device in Fig. 1, the laterite-type nickel ore with a particle size of less than 10mm is supplied to the suspension heat exchanger 2 with a screw conveyor of 220t / h. The laterite-type nickel ore contains:

[0070] 1.75wt% NiO

[0071] 31.4wt% Fe 2 o 3

[0072] 11wt% moisture

[0073] After passing through the first and second preheating sections, the pre-dried nickel ore is introduced into a calcining reactor 8 through a pipeline 7 . In addition, 6200Nm 3 / h natural gas as fuel (via pipeline 19), 71000Nm 3 / h air as combustion gas (through pipe 21) and 32600Nm 3 / h The waste gas from the reduction reactor (via pipeline 20) is supplied to the calcination reactor 8 through the center pipe 9, the gas temperature is about 800 ° C, and its composition is as follows:

[0074] 2vol%H 2

[0075] 18vol%H 2 o

[0076] 10vol% CO

[0077] 14vol% CO 2

[0078] 1vol%CH 4

[0079] 44vol%N 2

[00...

Embodiment 2

[0087] Embodiment 2 (heat treatment iron ore containing chromium)

[0088] exist figure 2 In the device, the 30t / h moisture content is 5wt%, Cr 2 o 3 Iron oxide-containing chromium ore with a content of 53 wt % and a particle size of not more than 6 mm is supplied to a reactor 8 through a pipe 7 .

[0089] 4500Nm 3 / h Fuel gas is supplied to combustion chamber 29 through pipeline 19, 5800Nm 3 / h The air preheated to 450°C is supplied to the combustion chamber 29 through the pipe 21', 4480Nm 3 / h The recirculation gas, also preheated to 450° C., is supplied to the combustion chamber 29 via the line 32 . On the opposite side of the combustion chamber, the temperature generated by combustion is about 13600Nm at 1600°C 3 / h The hot process gas is pumped through the pipe 20 and supplied to the reactor through the central pipe 9 . In addition, 7100Nm 3 / h Air is fed into the reactor via line 13 as fluidizing gas.

[0090] 21300Nm at 1100°C is extracted from the cyclone sepa...

Embodiment 3

[0091] Embodiment 3 (heat treatment iron ore)

[0092] exist image 3 In the device, the 178t / h moisture content is 5wt%, Fe 2 o 3 Moist iron ore (hematite) with a content of 80 wt% and a particle size of less than 10mm is supplied to the suspension heat exchanger 2 through the screw conveyor 1, dried with exhaust gas from the cyclone separator 6, and preheated to about 277°C. The exhaust gas from cyclone separator 6 has the following composition:

[0093] 46.9vol% N 2

[0094] 7.6vol% H 2

[0095] 11.4vol%H 2 o

[0096] 5.7vol% CO

[0097] 28.4vol% CO 2

[0098] The solids are then separated from the gas phase in cyclone 3 and conveyed to suspension heat exchanger 5 where they are further heated to 561 ℃. The material then enters the annular fluidized bed 12 of the reactor 8 via the cyclone 6 and the conduit 7 .

[0099] 13000Nm 3 / h air (pipe 19) and 103000Nm 3 / h From the smelting reduction reactor 14' a mixture of hot off-gas (pipe 20) at about 1000°C is supp...

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Abstract

The present invention relates to a method and a plant for the heat treatment of solids containing iron oxide, in which fine-grained solids are heated to a temperature of 700 to 1150 DEG C in a fluidized bed reactor (8) . To improve the utilization of energy, it is proposed to introduce a first gas or gas mixture from below through at least one gas supply tube (9) into a mixing chamber region (15) of the reactor (8), the gas supply tube (9) being at least partly surrounded by a stationary annular fluidized bed (12) which is fluidized by supplying fluidizing gas. The gas velocities of the first gas or gas mixture and of the fluidizing gas for the annular fluidized bed (12) are adjusted such that the Particle-Froude-Numbers in the gas supply tube (9) are between 1 and 100, in the annular fluidized bed (12) between 0.02 and 2, and in the mixing chamber (15) between 0.3 and 30.

Description

technical field [0001] The invention relates to a process for the thermal treatment of iron oxide-containing solids, in which fine-grained solids are heated to a temperature of 700-1150° C. in a fluidized bed reactor, and to a corresponding apparatus. Background technique [0002] Such methods and devices are used in the melting of ores, for example in the production of iron from iron ores, in the production of ferronickel from iron-nickel ores, etc. The ore is reduced in successive process stages before being heat treated in this way. Although this preheating of iron oxide-containing ores has previously been mainly carried out in rotary kilns, fluidized bed reactors have also been used for this purpose for many years. [0003] Known from EP0222452B1 is a method for obtaining low-valent metal oxides by reducing metal oxides with a carbon-containing reducing agent, wherein first, in the first reactor in which hot gas is used to suspend solids, the hot gas at 800-1100 ° C is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/10C22B5/14B01J8/18B01J8/44F27B15/02F27B15/10B01J8/30F27B15/08
CPCB01J2208/00061B01J8/18C22B1/10B01J8/30B01J8/44B01J8/1863C22B5/14F27B15/10F27B15/08F27B15/02
Inventor A·欧瑟M·赫尔施P·韦伯S·斯尼德D·奴贝尔M·斯特罗德
Owner METSO OUTOTEC (FINLAND) OY
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