Arrangement for the dosed introduction of fine-particulate...

Details Arrangement for the dosed introduction of fine-particulate... Arrangement for the dosed introduction of fine-particulate...

1999-04-07

2001-04-03

Kastler, Scott (Department: 1742)

Metallurgical apparatus

Process

C266S172000, C266S216000

Reexamination Certificate

active

06210627

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an arrangement for the dosed introduction of fine-particulate material into a reactor vessel, comprising a fluidized bed sluice, into which a material supply means enters from above and into which a gas duct feeding a fluidization gas runs in the lower end region thereof and which includes an overflow tube for conveying on the fine-particulate material, as well as to a plant including an arrangement of this type and a method of operating this arrangement.
2. Description of the Related Art
An arrangement of the aforementioned type is known from U.S. Pat. No. 4,277,205. This arrangement features a central tube, from which a plurality of overflow tubes lead to charging points distributed over the cross section of the reactor vessel. The central tube, together with the overflow tubes, is arranged inside the reactor vessel in a way that it can be turned in order to ensure a uniform distribution of the fine-particulate material in the reactor vessel. The arrangement inside the reactor vessel is required for turning the overflow tubes but causes heavy wearing-out of the turning mechanism and of the seals, particularly if the reactor vessel is used for reactions taking place at higher temperatures and if violent gas flows occur.
The known arrangement has the disadvantage that the fine-particulate material can be fed into the reactor vessel only uniformly distributed over the cross section but not specifically to certain charging points or charging zones.
SUMMARY OF THE INVENTION
The object of the invention is to avoid these disadvantages and difficulties and to create an arrangement of the aforementioned type and a method of operating this arrangement, which allow a dosed introduction of fine-particulate material into the reactor vessel. In particular, the time-dependent feeding of fine-particulate material at specific points in various zones of the reactor vessel has to be made possible, wherein the arrangement, however, may be of rigid and fixed design so as to avoid wear problems and to minimize investment and maintenance expenses.
Another object of the invention is to create an arrangement for the introduction of fine-particulate reduction product from charging substances comprised of ore, in particular, iron ore and fluxes and at least partially having a portion of fines at an arrangement for the production of metal melts, in particular pig iron, wherein the reduction product forms highly gas-permeable zones, which, however, are connected with one another three-dimensionally, thus ensuring good accessibility for the reducing gas.
According to the invention, this problem is solved in an arrangement of the aforementioned type by a plurality of fluidized bed sluices which provided outside of the reactor vessel and which can be connected and disconnected independently of one another, whose overflow tubes project into the interior of the reactor vessel.
A preferred embodiment is characterized in that the arrangement is provided with a central tube forming a fluidized bed sluice and that at least two overflow tubes, each running into a further fluidized bed sluice, depart from the central tube, wherein each further fluidized bed sluice is formed by a receptacle, into which a gas duct feeding a fluidization gas runs in the lower region thereof and from which at least one overflow tube departs, running into the reactor vessel, and wherein the fluidization gas ducts each are equipped with valves for the locally dosed introduction of the fine-particulate material.
By means of the valves, individual or several of the further fluidized bed sluices enclosing the central tube can be activated or deactivated. The fine-particulate material first accumulates in the central tube and, when the central tube is being charged with a fluidization gas, also fills the further fluidized bed sluices. Depending on whether a fluidization gas is fed to one of the further fluidized bed sluices, this fluidized bed sluice becomes clear and the fine-particulate material can enter the reactor vessel from this fluidized bed sluice via the overflow tube. By alternately connecting the fluidization gas, the material flow and, thus, also the charging point or charging zone in the reactor vessel can be varied. Furthermore, the fine-particulate material can be dosed via the gas volume, therefore the valves are expediently designed as flow control valves.
It has been proved that a dosed introduction is expediently accomplished by means of at least two, yet eight at the most, and preferably three or four fluidized bed sluices.
In order to prevent the fine-particulate material entering the reactor vessel through an overflow tube in the form of a strand from fanning, the ends of the overflow tubes running into the reactor vessel are advantageously provided with a gas feeding means for forming a gas jacket developing on the lower end of the overflow tube, wherein the overflow tube expediently comprises a double jacket defining an annular gap cavity and the gas feeding means runs into the annular gap cavity.
For the formation of a gas jacket, the lower end of the overflow tube is preferably provided with an annular gap opening or several openings for the exit of a gas flowing through the annular gap cavity.
To allow charging of fine-particulate material to the entire cross section of the reactor gas, the fluidized bed sluices are expediently provided at a distance from the central tube and preferably in a radially symmetric arrangement.
An arrangement for the production of metal melts, in particular, pig iron, from charging substances comprised of ore, in particular, iron ore and fluxes and at least partially having a portion of fines, is characterized by at least two fluidized bed reactors consecutively connected in series, wherein the ore is conducted from one fluidized bed reactor to another fluidized bed reactor via conveying ducts in one direction and the reducing gas is conducted from one fluidized bed reactor to another fluidized bed reactor via reducing-gas connection ducts in the opposite direction, and by a melter gasifier, into which a supply duct conducting the reduction product from the fluidized bed reactor arranged last in the flow direction of the ore runs via an arrangement for the dosed introduction of the fine-particulate reduction product, as well as a duct supplying carbon and another duct supplying oxygen, a reducing-gas conveying duct departing from the melter gasifier and running into the fluidized bed reactor arranged last in the flow direction of the ore.
The gas ducts for feeding the fluidization gas advantageously depart from a reducing-gas conveying duct.
In order to form a highly gas-permeable bed from the fine-particulate material in the reactor vessel, the fluidized bed sluices, which are preferably arranged beside the central tube, are alternately activated.
According to a preferred embodiment, the fluidized bed sluices are activated on grounds of process measurements of a process occurring in the reactor vessel, by means of which the position of a charging point or charging zone for fine-particulate material is determined in the reactor vessel, whereupon the fine-particulate material is distributed by specifically switching off and on the fluidized bed sluices.


REFERENCES:
patent: 4277205 (1981-07-01), Meunier
patent: 4613113 (1986-09-01), Saito et al.
patent: 5413315 (1995-05-01), Venas et al.
patent: 2805816 (1979-08-01), None
patent: 0063924 (1982-11-01), None
patent: 58-210110 (1983-12-01), None
patent: 90/07010 (1990-06-01), None

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