SU1401241A1 - Rotary tubular furnace for thermal treatment of loose materials - Google Patents

Abstract

The invention relates to heat treatment of bulk materials in anti-rotation furnaces and is used in metallurgy. The purpose of the invention is to increase productivity and product quality, as well as reduce fuel consumption. The device inside the rotary kiln 1 of the partitions 4 in the form of rectangular plates, the upper face of which is located at the height of the pouring layer and which are arranged along a helical line, makes it possible to average the treatment time in the furnace of small and large materials. Using the invention increases productivity by 2-6% and reduces fuel consumption. 2 Il. g

Description

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This invention relates to the heat treatment of bulk materials in rotary kilns and can be used in ferrous and nonferrous metallurgy and other industries.

The purpose of the invention is to increase the productivity of the furnace and the quality of the finished product, as well as reduce fuel consumption.

FIG. 1 shows the proposed furnace, a cross-section; in fig. 2 - the same, longitudinal section.

The rotary kiln consists of a metal casing 1 lined with refractory material 2, with the help of legs 3, the partition 4 is attached to the casing of the furnace. The partition and its fastenings are made of heat-resistant material. The distance of the AC (Fig. 1) is equal to the height of the layer, and the sun is equal to the height of the spilling layer. The distance AB between the partitions is equal to the length of the path passed by the clumping of the material parts for one clumping along the axis of the furnace.

The furnace works as follows.

In position a (Fig. 1), the partition is in the superlayer space and is washed by furnace gases. As the septum is immersed in a layer of material, located in the H | AD | D2CH2 segment (Fig. 1), the dropping HiBDiD2CH2 layer (Fig. 1, position b), consisting mainly of particles of the largest fractions of the material, is delayed in its longitudinal movement. the bulkhead while the rest of the material H | AD | BH | gets the opportunity to move freely in the longitudinal (axial) direction under the septum.

Coalescent coarse particles are retained, for example, by a partition 5 (Fig. 2) until its end portion is immersed in the layer. At this moment, all the particles of the layer are allowed to move along the axis of the furnace, but large particles of the clumping layer move only up to the partition 6 (Fig. 2), which begins to sink into the layer. Thus, the fine particles of the material are propelled without impediment along the axis of the furnace, and the large particles in the shedding layer freely move only from the partition to the partition, which retards their progress along the furnace. The height of the partition is set equal to the height of the dropping layer, which is equal to 1/3 of the entire height of the layer, i.e., 0.032-0.127 of the furnace diameter.

Thus, the lower edge of the septum passes along the boundary of the shedding layer - the main part of the layer. If the lower edge is lower than the border, the partition delays not only large but also small fractions, if higher, when falling down under the blade, large fractions pass without delaying. The length of the partition is uniquely determined by its height and is equal to the chord of the layer of material. If the length is greater than the chord, a part of the blade is above the layer and does not delay the shedding layer, if less, some of the large fractions of the material in the upper part of the shedding layer pass over the partition without being delayed by it.

The distance between the partitions is equal to the length of the path traveled by the dropping material particle at one time along the furnace axis. If it is smaller, the partitions “work like. a ring, and the material accumulates in front of them if the effectiveness of the partitioning system is reduced.

The number of partitions installed in the furnace may be different and depends on the difference in the sizes of small and large fractions: the larger the difference in size, the greater the partition length of the furnace. The length of the furnace on which the partitions are installed should provide an increase in the residence time of large fractions, which is necessary to complete the heat treatment processes. The partition is installed in a plane perpendicular to the longitudinal axis of the furnace or turned at an angle of up to 4 ° in the direction opposite to the direction of the material dvizhenie, since the angle of inclination of the longitudinal axis of the furnace relative to the horizontal plane does not exceed, as a rule, 4 °. If the partition is turned in the direction of movement of the material, the effectiveness of the delay of the material by the partition decreases, with an angle of more than 4 °, the partition begins to "work as a paddle.

Example. The furnace for heat treatment of ore has a length of 43 m, a clear diameter of 5.7 m, a revolutions of 1 per minute, an inclination angle of 2.5 °, a minimum piece size of 10 mm, a maximum of 20 mm, a capacity of 300 tons / hour.

The furnace is characterized by a filling rate of 7.5% with a layer height of 0.73 m, a residence time of a piece of an average size of 44 mm, pieces of 10 and 20 mm in size 57 and 35 minutes, respectively.

For such a furnace, it is necessary to install partitions with a height of 0.73 m, a height of the working part of 0.24 m, and a distance of 0.2 m from one another. on the length of the furnace 21.4 m.

Calculations on the time required for roasting pieces of various sizes show that for a piece of 15 mm it takes 44 minutes, 20 mm - 53 minutes and 10 mm - 36 minutes. Thus, a furnace without partitions (or with blades) provides the required time

Claims (1)

Claim A rotary tube furnace for heat treatment of bulk materials, containing a lined body with baffles fixed inside on a helical line, characterized in that, in order to increase productivity, product quality and reduce fuel consumption, the baffles are made in the form of 10 straight coal plates with a height of 0.095-0, 38 diameters of the furnace and are installed in planes perpendicular to the longitudinal axis of the furnace or rotated by an angle of up to 4 ° in the direction opposite to the direction of movement of the material, while the height of the working surface and the furnace is 0,032-0,127 diameter. on the Compiled by A. Ashikhin Editor I. Gornaya Order 2530/36 Tehred I. Veres Corrector A. Tyasco Circulation 560 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 1 13035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, Uzhhorod, st. Project, 4