SU996835A1 - Electric furnace for graphitizing of carbon blanks - Google Patents

Description

one

The invention relates to electrothermal, in particular, electric furnaces designed for the graphitization of carbon blanks.

Closest to the invention is an electric resistance furnace for graphitizing carbon blanks, including a refractory body, current-carrying electrodes fixed in its end walls lined from the inside of the body with graphite blocks (forming a graphite wall - screen of current leads) perpendicular to the core, furnace core and heat insulation around the core. Between the end refractory and graphite wall, the electric graphite furnace contains a layer of graphite c-group 1.

Known oven works as follows.

Annealed electrode blanks are placed in the case, a fraction of 25-10 mm is filled with coke nut filling with a coke nut filling, and a layer of graphite coke 250-300 mm thick, 25-10 mm thick is poured between the blanks and the graphite wall.

(assigning a graphite coke to create a current conductor through the graphite wall to the furnace core). Get the conductor. The main package is the core of the furnace. The core is surrounded by fine carbon thermal insulation (coke breeze). the furnace is connected to a power source by means of current-carrying electrodes, an electric current is passed through the core of the furnace, 1 (which causes heating of the electrode blanks, as well as

0 current lead electrodes themselves and an internal graphite lining (screen of current leads) up to temperatures of 2500-2800 C.

The famous oven has a number of drawbacks.

The temperature resistance of the casing (walls and bottom) in the place adjoining the graphite lining of the end walls (screen of current leads) is low.

The greater thermal conductivity of the graphite lining of the end walls causes the body to heat up to temperatures exceeding the thermal resistance of the refractory walls and the bottom.

The heat losses are great:) nergin and on-heating the graphite lining of the end face itself, 39968 wall (screen of current leads), which occupies a volume of 3 to 4.5 m, and heat loss due to heat transfer from the graphite lining (screen of current leads) to the end face refractory cieiiKe. The presence in the furnace of a graphite lining wall (screen of current leads) entails a high consumption of graphite blocks (from 5 to 7 tons per two ends of the furnace). The lining wall of graphite blocks d (screen of current leads) creates a negative effect of current spreading over the entire cross section of the furnace, causing additional heating of the thermal insulation, the bottom and walls of the furnace, reducing the current density in the core, reducing the quality of the graphitized product. The purpose of the invention is to increase the durability of the refractory masonry of the kiln, reducing the consumption of graphite lining materials and heat losses. This goal is achieved by the fact that in an electric furnace containing a refractory body, current-carrying electrodes fixed in the end walls, a core of the furnace and heat insulation, heat insulation in the end part of the furnace is located around the current-carrying electrodes between the end, side walls and the bottom. Moreover, graphite columns were mounted between the ends of the current-carrying electrodes and the bottom. The location of the thermal insulation in the end part of the furnace surrounding the current-carrying electrodes with a continuous layer between the refractory end-face, side walls and the bottom leads to the fact that the core of the furnace, the layer and graphitized coking and current-conducting electrodes form a single current conductor surrounded on all sides by a layer of heat insulating charge . Spreading in the thermal insulation layer is reduced due to the absence of a graphite screen of the current leads in the thermal insulation layer, the current density in the core increases. The ends of the current-carrying electrodes (square or round section), located above the bottom, rest on the graphite bucket to prevent settling current-conducting electrodes. For current-carrying electrodes of circular cross-section, the connection of the superposed electrodes with graphite bars preventing the deposition of electrodes is also provided. FIG. 1 shows schematically an electric furnace with current-carrying square square electrodes; in fig. 2 electric oven with circular current electrodes. An electric resistance furnace for graphitating carbon blanks consists of a refractory body 1, current-carrying electrodes 2 fixed in opposite end fire-resistant walls perpendicular to them, the core of the furnace formed by electrode blanks 3 arranged perpendicular to the longitudinal axis of the furnace, parallel to each other without gaps vertical rows and with intervals equal to 0.2 of the diameter of the blanks in horizontal rows filled with dried metallurgical coke 4 fractions of 25-10 mm layer graphitized coke 5 with a thickness of 250–300 mm of a 25–10 mm fraction adjacent to the current-carrying electrodes (electrical resistance of graphite coke 5 is 2–3 times less than that used for transferring dried metallurgical coke billet 4). The core of the furnace, consisting of blanks 3 with intervals in horizontal rows covered with dried coke 4, and a layer of graphite coke 5, as well as current-carrying electrodes 2 inside the furnace space are surrounded on all sides by a thermal insulation layer 6 with a thickness of 450-700 mm. On the inner side of the housing 1, the current-carrying electrodes 2 are supported on columns 7 of graphite material mounted on the bottom (in the embodiment of the furnace with current lead 1 square electrodes 2 of circular section, all of them are connected to each other by graphite columns). The furnace works as follows. , A layer of heat insulation 6 with a thickness of 600-700 mm is poured on the refractory bottom of the furnace body. Metal shields (ng; shown) are installed parallel to each other along the longitudinal axis of the furnace between the end walls of the layer with the distance between them equal to the length of the electrode blanks 3 being loaded. Metal double shields are installed at the ends of the furnace between the longitudinal metal shields (with they are 250–300 mm) close to the current-carrying electrodes 2. Thermal insulation 6 between the metal side and end shields is filled with dried metallurgical coke 4 fractions 25–10 mm with a layer of 80–100 mm, onto which pendikul to the longitudinal axis of the furnace stack row electrode blanks 3 with a distance therebetween 0.2 Diameter of the preform. The gaps between the billets are filled up with 4) 25–10 mm of dried metallurgical coke. 59 Similarly, I place the second and subsequent rows of blanks over the entire height of the core. Dual metal shields at the furnace ends fall asleep graphite coke 5 of fraction 25-10 mm to the core height. A distance of 450-600 mm between the side shields and the walls of the entire core height is covered with a layer of thermal insulation 6. After that, the metal side and end shields are removed with the help of a crane. Then, the top of the furnace over the entire length and width of the furnace is covered with a layer of thermal insulation 600-700 mm thick. Thus, with the help of metal shields, a core of the furnace is formed, surrounded by a heat insulation layer 6. The current carrying electrodes 2 and graphite columns 7 are also surrounded by a heat insulation layer 6 between the refractory face, side walls and the bottom of the body. The proposed furnace allows you to increase the thermal resistance of the refractory masonry of the body by 1.5-2 times, reduce the consumption of graphite lining materials by 80-90%, reduce 5 technical losses by 30-40% compared to the prototype .., inventive 1. Electrical furnace dp graphite carbon blanks containing a refractory body, current-carrying electrodes reinforced in the end walls, a core and thermal insulation, in order to increase the resistance of the refractory masonry of the furnace, reduce the consumption of graphite lining materials and heat Heat losses in the end part of the furnace are located by a continuous layer surrounding the current-carrying electrodes between the end, side walls and the bottom. 2. A furnace according to claim I, characterized in that graphite columns are mounted between the ends of the current-carrying electrodes and the bottom. Sources of information taken into account in the examination 1. Issues of graphitization of carbon materials. Collection of ed. I. F. Sukhorukova, M., 1968, part I, p. 19, FIG. one.

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Claims (2)

Claim 1. An electric furnace for graphitization of carbon billets, containing a refractory body, current-conducting electrodes mounted in the end walls, core and thermal insulation, characterized in that, in order to increase the resistance of the refractory masonry of the furnace, reduce the consumption of graphite lining materials and heat losses, thermal insulation in the end part of the furnace is located surrounding the current-carrying electrodes in a continuous layer between the end, side walls and the bottom. 2. Oven pop. 1, characterized in that between the ends of the current-carrying, electrodes and the bottom are mounted graphite columns.