DE102008017010A1 - Modular electric reduction furnace - Google Patents

Abstract

Electro reduction furnaces, which can be used as an industrial SAF in ferroalloying and NE processes for experimental purposes and in a simplified design, require a complete engineering just like larger furnaces, whereby the engineering costs are disproportionately large as they do not match the furnace size decrease, but in large part represent a kind of "fixed costs". Furthermore, changes to existing stoves - large or small - are very complex. Once built ovens can be difficult to adjust or change mechanically. In order to develop a smaller flexible reduction furnace, which makes it possible to provide low-cost projecting and yet process-specific customizable reduction ovens for experimental operation or in a simplified design for a corresponding industrial use, the invention proposes the electric reduction furnace (1) without a welded steel construction completely dismantled from any interchangeable modules form and the dimensions and structure of the electric reduction furnace (1) with respect to the furnace vessel (2), the side walls (3), the bottom (4), the ceiling (5) and the arrangement of the To make electrodes (6) individually variable by using individual and / or multiple modules with different dimensions and materials.

Description

The The invention relates to an electric reduction furnace with any, For example, round or rectangular, cross-sectional shape of the furnace vessel, the in ferroalloying and NE processes (NE = non-ferrous metals) too Experimental and simplified design with the elimination of the experimental options can be used as industrial SAF (Submerged Arc Furnace).

Known smaller electric reduction furnaces require just like larger ovens each a complete engineering. Once built ovens can be mechanically difficult adapted or changed become. A possible Standardization limited on dimensions and types, but less on the universal applicability individual components. Regarding the electrical operation can well-known ovens alternately operated in different interconnections, Often, however, mechanical components have been extensively rebuilt before or even have to be changed, which as a rule individual solutions required.

at small stoves fall in addition the engineering costs disproportionately in the weight, because they do not decrease with the size of the oven, but to a large extent constitute a kind of "fixed costs." Changes existing stoves - big or small - are very consuming. There is therefore the difficulty to market small ovens, as the market It is difficult to convey that the cost of engineering and manufacturing small stoves not the same as the nominal power drops.

outgoing From this described prior art, it is an object of the invention, specify a smaller flexible reduction furnace, which allows inexpensive to be configured and yet process-specific customizable reduction ovens for the experimental operation or for to design a corresponding industrial use.

The Asked object is with the characterizing features of the claim 1 solved by that the electric reduction furnace completely dismantled from any interchangeable Modules is formed, wherein for power ratings above 5 MVA as a performance limit an uneconomic expectant Total construction applies, depending on the design and use of the furnace u. a. for example, to the supporting Recording of strain stresses is required, and that the dimensions and the structure of the electric reduction furnace with respect to the furnace vessel, the Side walls, the floor, the ceiling and the arrangement of the electrodes by use single and / or multiple modules with different dimensions and materials individually customizable and, for example for industrial used ovens the for different processes required different hearth heights in substantially easily changeable are.

The modular design with quickly exchangeable segments, with individual or several modules also welded constructions could be, relieved by their suitability for preferably numerous electrical modes of operation when used as a test furnace the adaptation to different experimental objectives from example the field of non-ferrous metals and slag cleaning, production of steel and ferroalloys and the utilization of metallurgical materials. Also for the exam of refractory and sidewall cooling concepts (Channel cooling, Rieselkühlung, different copper cooling concepts) is this multifunctional invention Electric reduction furnace ideally suited.

The Modular design facilitated by the transfer of individual elements after her probation in the industrial scale the design and customization of smaller ovens, the then also according to the invention composed of a "kit" can be. Advantageously, such smaller ovens then, for example, at a later one Process or product change in a simple and fast way the changed conditions to adjust.

Thus, the sidewalls of the furnace vessel are subdivided into vascular rings of possibly different heights for rapid height and lining adaptation, which in turn are divided into vascular ring segments, for example halves or thirds. These vessel ring segments sometimes have different tasks and, accordingly, sometimes different heights. For example, at the front, a metal tapping segment and a slag tapping segment may overlap, while the segment on the opposite side is as high as the metal tapping segment and the slag tapping segment together. By using individual standardized, for example, curved, trained vessel ring segments, which are linked together in any desired number, it is also possible, for example, to form pseudo-round and / or angular vessel rings with different-sized diameters. The electric reduction furnace according to the invention thus goes away from the welded steel construction and also from the idea that a furnace inevitably has to be round on the outside to absorb expansion forces. These can also be chained curved elements.

• – DC-Betrieb und 1 bis 3 Elektroden mit Bodenelektrode,
• – AC/DC-Betrieb und 1 Elektrode mit Bodenelektrode,
• – DC-Betrieb mit 2 Elektroden ohne Bodenelektrode,
• – DC-Betrieb mit 2 Elektroden mit Bodenelektrode,
• – AC-Betrieb mit 3 Elektroden direkt am Drei-Phasen-Netz für kleine Leistungen,
• – AC-Betrieb mit 3 Elektroden in üblicher Verschaltung und Steuerung.

The modular design also includes the individually possible different electrical modes of operation. For example, the bottom of the electric reduction furnace can be made of an electrically conductive material to perform experiments with a bottom electrode. Furthermore, by means of a corresponding geometry of the electrode leadthrough and an intelligent connection of the electrical connection, an AC and DC operation and the use of numerous different electrical operating modes are made possible, wherein the following, partly also suitable for use on an industrial scale suitable changeable electrical operations are feasible:

• - DC operation and 1 to 3 electrodes with bottom electrode,
• - AC / DC operation and 1 electrode with bottom electrode,
• - DC operation with 2 electrodes without bottom electrode,
• - DC operation with 2 electrodes with bottom electrode,
• - AC operation with 3 electrodes directly on the three-phase network for low power,
• - AC operation with 3 electrodes in usual wiring and control.

• – Möglichkeit, auch ohne AC-Elektrik einen AC-Betrieb mit 3-Elektroden im DC-Betrieb hinsichtlich des Stromflusses nachahmen zu können,
• – schnelle Korrektur z. B. der Herdhöhe bei industriellen Ofengrößen,
• – rationellere Konstruktion und Fertigung, insbesondere von selteneren Ofentypen,
• – vereinfachte Wartung und Kontrolle des Ofens im Betrieb,
• – schneller Austausch einzelner Segmente,
• – Möglichkeit der Lagerhaltung einzelner Bauteile,
• – schnelles Engineering durch Verwendung eines modularen Baukastensystems,
• – Möglichkeit der Vorbereitung späterer Umbauten.

In summary, the following advantages are given by the electric reduction furnace of the invention:

• - Ability to mimic an AC operation with 3-electrodes in DC operation with respect to the current flow, even without AC electrics,
• - fast correction z. B. the hearth height in industrial furnace sizes,
• - more rational design and manufacturing, especially of rare types of furnaces,
• - simplified maintenance and control of the furnace during operation,
• - fast exchange of individual segments,
• - possibility of storing individual components,
• - fast engineering through the use of a modular system,
• - Possibility of preparing later conversions.

Further Advantages and details of the invention are given below in schematic drawings illustrated embodiments explained in more detail.

It demonstrate:

1 an electric reduction furnace with missing side wall segment in a perspective side view obliquely from above,

2 two side wall segments in a perspective side view,

3 an electric reduction furnace in an exploded perspective view,

4 a pseudo-circular vascular ring formed from standardized vascular ring segments,

5 a concatenation of standardized vascular ring segments,

6 an electrode arrangement in a plan view,

7 an electrical wiring diagram.

In the 1 is an electric reduction furnace 1 shown in a perspective side view. It consists essentially of a furnace vessel 2 with a side wall 3 a floor 4 and a blanket 5 , Through in the ceiling 5 existing openings are from the top of the furnace vessel 2 on electrode arms 8th held electrodes 6 introduced, with the vertical displacement of the electrodes 6 the electrode arms 8th on guide frames 9 are movably attached. The electrode arms 8th serve here in addition to holding the necessary for the operation supply of electrical energy by means of a high current path 10 , To document the modular design and to have a look into the furnace vessel 2 was allowed in the 1 one of originally three existing sidewall segments 30 (see. 2 ), the side wall 3 form, as well as a corresponding large section of the soil 4 away. At one of the remaining sidewall segments 30 (see. 2 ) is a melting trough 23 arranged.

In the 2 are the two sidewall segments 30 (in the figure on the left with the melting channel 23 and right with belonging bottom section 4 ) of the 1 individually shown in a perspective side view. The sidewall segments 30 are made of individual superimposed vascular ring segments 21 constructed, one as a metal tapping segment or Schlackenabstichsegment with a melting trough 23 is provided.

To further illustrate the inventive modular design of the electric reduction furnace 1 is this in the 3 shown in a perspective exploded view. Individual components of the electric reduction furnace 1 are that way opposite the 1 to recognize more clearly. So it can be seen that the ground 4 from two superimposed layers 41 . 42 is formed, wherein the use of the soil 4 as bottom electrode 7 the upper layer 41 can be made for example of an electrically conductive material.

The 4 shows in a plan view of a pseudo-circular vascular ring 20 , which in this embodiment consists of five standardized curved vessel ring segments 22 is formed, which are releasably linked together. The number of five vascular ring segments used here 22 is arbitrarily changeable, with as meaningful lower limit three interconnected vascular ring segments 22 apply, which then give a 3-cornered furnace vessel, while a larger number of the round shape continues to approach. A possible embodiment of such a Verket device 24 is in the 5 shown, each vessel ring segment 22 in the adjacent vessel ring segment 22 is hung from above.

A possible arrangement of the electrodes 6 with their electrode arms 8th as well as the electrical connections 11 is in the 6 shown. From this representation, the inside of the furnace vessel 2 freely adjustable to each other (within a correspondingly shaped opening in the furnace lid, which may be preferably designed in a y-shape) of the electrodes 6 which is necessary to realize different interconnections. A possible electrical connection for this purpose for DC (=) or AC (~) is in the 7 Refer to the circuit diagram reproduced. It shows the switches S2, S3 and S4 for the electrodes 6 and the switches S1 and S5 for the bottom electrode 7 , The following operating modes are then possible with this interconnection: Switch: S1 S2 S3 S4 S5 Switch positions: DC operation with three electrodes and bottom electrode OUT ONE ONE ONE ONE DC / AC operation with one electrode and bottom electrode OUT OUT ONE OUT ONE DC operation with two electrodes without bottom electrode ONE ONE OUT ONE OUT DC operation with two electrodes and bottom electrode OUT ONE OUT ONE ONE AC operation with three electrodes without bottom electrode OUT ONE ONE ONE OUT

1

Electro-reduction furnace

2

furnace vessel

3

Side wall

4

ground

5

blanket

6

electrode

7

bottom electrode

8th

electrode arm

9

guide frame

10

High current path

11

Electrical connection

20

vascular ring

21

Vascular ring segment

22

standardized Vascular ring segment

23

melting gutter

24

concatenation

30

Side wall segment

41 42

the Soil forming layers

S1-S5

switch

~

alternating current (AC operation)

=

direct current (DC operation)

Claims (7)

Electric reduction furnace ( 1 ) with any, for example round or rectangular, cross-sectional shape of the furnace vessel ( 2 ) which can be used as an industrial SAF in ferroalloying and non-ferrous processes for experimental purposes and in a simplified design, with the elimination of the experimental options, characterized in that - the electric reduction furnace ( 1 ) is designed to be completely dismantled from any interchangeable modules, for power levels above 5 MVA as performance limit an uneconomical overall design applies, depending on the design and use of the furnace, inter alia, for example, to support the absorption of strain stresses required - the dimensions and structure of the electric Reduction furnace ( 1 ) with respect to the furnace vessel ( 2 ), the side walls ( 3 ), of the soil ( 4 ), the ceiling ( 5 ) and the arrangement of the electrodes ( 6 ) individually variable by using individual and / or multiple modules with different dimensions and materials and, for example, for industrial ovens required for different processes different hearth heights are changed in a simple manner. Electric reduction furnace ( 1 ) according to claim 1, characterized in that one or more modules are welded constructions. Electric reduction furnace ( 1 ) according to claim 1 or 2, characterized in that for fast height and brick lining adaptation the side walls ( 3 ) of the furnace vessel ( 2 ) in vascular rings ( 20 ) with sidewall segments ( 30 ) are divided. Electric reduction furnace ( 1 ) according to claim 3, characterized in that for the formation of the side wall segments ( 30 ) the vascular rings ( 20 ) in vessel ring segments ( 21 . 22 ) are divided. Electric reduction furnace ( 1 ) according to claim 4, characterized in that the vessel ring segments ( 22 ) standardized, for example, are formed bent and in any number to pseudo-circular and / or square vascular rings ( 20 ) can be linked together with different diameters. Electric reduction furnace ( 1 ) according to claim 1, 2, 3, 4 or 5, characterized in that the bottom ( 4 ) for use as a bottom electrode ( 7 ) with a layer made of an electrically conductive material ( 41 ) is provided. Electric reduction furnace ( 1 ) according to claim 1, 2, 3, 4, 5 or 6, characterized in that by a corresponding geometry of the electrode feedthrough and an intelligent connection of the electrical connection for AC and DC operation, the use of numerous different electrical modes is enabled, the following changeable electrical operating modes are feasible: - DC operation and 1 to 3 electrodes ( 6 ) with bottom electrode ( 7 ), - AC / DC operation and 1 electrode ( 6 ) with bottom electrode ( 7 ), - DC operation with 2 electrodes ( 6 ) without bottom electrode, - DC operation with 2 electrodes ( 6 ) with bottom electrode ( 7 ), - AC operation with 3 electrodes ( 6 ) directly on the three-phase network for low power, - AC operation with three electrodes ( 6 ) without bottom electrode with usual wiring and control.