SU881502A1 - Circular furnace rotary hearth - Google Patents

Description

Iobregion refers to industrial ring furnaces, for TeJDMO processing of various bulk and Molded materials, and more specifically to the device of the upper, most heat-stressed part of the lining of the rotating hearth. Verbene lining designs and parts of rotary hearth furnaces for heat treatment of carbon-containing bulk and dust materials made of refractory bricks are known. However, when using brick or concrete (stuffed) hearths in ring furnaces for heat treatment of bulk materials (expanded clay, limestone, various ores, carbon-containing materials), there are signs of destruction of the upper, most heated, refractory insulation layer, which is reflected in the refractory insulation to the periphery (outside), pressing in from individual bricks and / or sections from pits from the general masonry massif, on the bottom of the hearth mirror and eversion of the side bricks, under the pressure of the main treasure ki In the case of the use of lining of concrete slabs, the phenomena of destruction are also noted, which are expressed in the gradual movement of the plates to the periphery, cracking of the plates, and attempts to secure the latter are unsuccessful. In addition, if there is a radial temperature gradient on the rotating bottom, significant tangential tensile stresses may occur, which can lead to the destruction of the upper part of the lining. The radial temperature gradient at the hearth may occur during the commissioning period or when deviating from the process mode during operation of the ring. The main cause of destruction, apparently, is the compression process — expansion of the lining elements under frequent heat cycles, and at the moment of compression of the lining elements friable ( dusty / material into the cracks formed, which, under the conditions of subsequent heating, results in a thrust pressure. and gradually increases and can reach 2500 kg / cm. Obviously,

that such high pressures do not develop in practice and the destruction of the upper part of the lining occurs somewhat earlier. Thus, the reason for the destruction is frequent heat exchange and the presence of granular (dusting material) on the hearth.

The closest to the invention, in essence and the result achieved, is under an annular furnace, which is an annular chute eosfilled with loose refractory material, and for sealing the furnace space it was proposed to use knives directly entering refractory bulk material 2,

However, such a structure cannot be used in an annular furnace for the treatment of bulk and / or dusty materials due to the mixing of the heat-treating material with a refractory backfill. Known designs of the linings of the upper part of the rotating hearth of ring furnaces cannot ensure a long-term campaign of installations during the heat treatment of bulk (dusty) materials.

The aim of the invention is to increase the durability of the rotating hearth.

This goal is achieved in that the rotating under the annular furnace, containing a chute filled with bulk material, and the engine, is equipped with one or two monolithic ring plates, lying freely on the bulk material. Fig. 1 shows a diagram of a part of a rotary hearth furnace for heat treatment of loose materials (dusting materials; Fig. 2 shows a variation of the embodiment of the ditch.

The rotary underneath is an annular groove 1, moving with the aid of an engine 2. The bottom of the groove is thermally insulated with lightweight fire, an upright or lightweight backfill 3 with low thermal conductivity. One or two annular monolithic plates 4 of low-CTE refractory material lie on the loose refractory material 5 in such a way that radial movements of the metal flanks of the annular groove 1, caused by cyclic thermal

loads do not lead to the destruction of monolithic annular plates 4, and the occurrence of a radial temperature gradient on the surface of the bottom for some reason causes an individual movement of each of the rings. Thus, a more significant expansion of the inner ring, which occurs under the action of a radial temperature gradient (i.e., the temperature on the inner ring is higher than on the outer one, does not result in tangential tensile forces on the outer ring. Eliminate direct contact of the metal sides of the groove lining ensures long-term operation of the entire structure when working with bulk or dusty materials

Tests show the reliability of this design and the possibility of heat treatment of ssggechy and / or dusting materials on it. This structure of the rotary hearth rotary kiln was tested on a semi-industrial heat treatment unit for carbon containing materials. The resistance of the proposed lining is 2 times higher than the resistance of the lining of the fire brick.

The use of this design allows to increase the durability of the lining 2 times and bring it to 5 months.

Claims (2)

1. Makarov G.N. Coke production in ring furnaces. Moscow, Metallurgists, 1972. 2. Authors certificate of the USSR 78624, cl. F 27 B 9/16, 1948. X. i. I ,. J-i iji 1 -LJ. t / g. / I. I II I I .LI i T Jl FIG. 2