SU1587067A1 - Method of drying pellets on conveyer machines - Google Patents

Abstract

This invention relates to the preparation of iron ore in ferrous metallurgy and can be used in the production of pellets. The purpose of the invention is to increase the productivity of the firing machines. Raw pellets are loaded on a calcining machine in two layers, and the lower and upper parts of the layer are dried alternately. The filtration rate of the drying agent through the bottom layer is set to 1.65-2.17 m / s, and for the upper layer of pellets - 2.2 ÷ 3.0 times lower than the filtration rate of the bottom layer. This method of drying the pellets is most effective in any direction of heat carrier movement through the bottom layer and when filtering the heat carrier from the bottom up through the top layer of pellets. The use of the invention will allow to increase the specific productivity of the machines, to reduce the heat consumption for drying and to improve the quality of the finished pellets. 1 il.

Description

The invention relates to the production of iron ore in ferrous metallurgy, namely, to the production of raw materials.

The circuit of the invention is an increase in the productivity of conveyor-type calcining machines.

The flow of raw materials is divided into two and loaded first into the lower one, then into the upper part of the bed. Separate drying of the lower and upper parts of the layer, which ensures alternate drying of the aforementioned layer in adjustable layers up to 200 mm high, allows one-sided filtration of the drying agent through the layer.

The drawing shows a scheme for alternately drying the lower and upper layers of the pellets.

On the conveyor belt 1 first load the bottom bed. The raw fibers are divided into two streams and are fed to the stackers 2 and 3. The roller layer 2 of the lower layer of the layer is fed directly to the bottom bed. Laying-down 3 top layer serves on the bottom layer. A heat carrier with a temperature is fed through the gas-gas chamber 4, it is filtered at a speed of 1.90 m / s through the bottom bed and the bottom layer of raw pellets, 80% of moisture is removed from it, and

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the upper gas passage chamber 5 is discharged from the system. At the same time, the residual (The moisture content in the bottom is 20%, which is sufficient to eliminate the destruction of the oats During their subsequent heat treatment. After the drying of the lower layer and feeding the upper layer of pellets to it, it is dried by filtration, the substrate is bottom-up through chamber 6. The filtration rate of the upper part of the float is set 2.5 times lower than the filtration rate of the lower part of the layer, i.e., 0.76 m / s and thereby ensures the completion of the Ifia moisture removal by 98% at sufficiently high rates. drying, sod neigh | elochi class -5 mm in the fired pellets thus is 2.21%.

; The filtration rate of the drying agent through the bottom layer is set to {equal to 1.65-2.17 m / s. At a lower speed without improving the quality of the finished product due to a decrease in the intensity of drying of the pellets, the specific productivity of the process decreases by 0.07. The higher consumption of the drying agent through the lower puff, the higher productivity of the calcining equipment, leads to an increase in the energy costs of the process and is also limited by the capacity of the blower equipment and the stability

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The filtration rate of the upper part of the layer in this case is set 2.2-3.0 times lower than the filtration rate of the lower part of the layer. With a higher filtration rate of the upper layer (less than 2.2 from the filtration rate

the lower layer) the pressure under the kiln carts increases excessively and the stability of the layer is disturbed, in particular, at the point of joining its lower and upper parts (the area with increased layer porosity). This increases the content of fines in the finished product, decreases the yield and decreases the productivity of the unit. With a lower filtration rate of the upper layer (more than 3.0 from the filtration rate of the lower layer), the quality of the finished product no longer changes, and the specific productivity of the roasting machine drops.

The method of drying the pellets, with their two-layer packaging, is most effective in any direction of heat carrier movement through the lower layer and in filtering the heat carrier from the bottom up through the upper layer of pellets.

The use of the proposed method allows to increase the specific productivity of the machines, reduce the heat consumption of the process and improve the quality of the burned plants,

Claims (1)

Invention Formula The method of drying pellets on conveyor machines, including filtering the coolant with a temperature of 200 through wet pellets, characterized in that, in order to increase the productivity of the machine, drying the pellets is carried out alternately first lower and then upper parts of the layer, and drying the lower part of the layer is carried out with the filtration rate of the coolant 1.65-2.17 m / s, and the upper part - 2.2-3.0 times less.