RU129614U1 - SHAFT FURNACE FOR FIRING BULK MATERIALS - Google Patents

Abstract

A shaft furnace for calcining bulk materials, comprising a lined shaft with heating, calcining and cooling zones, an air-cooled beam with windows for supplying cooling air to the furnace space located in the cooling zone, a gas distribution core cross-shaped in cross section, including a central ceramic support mounted on an air-cooled beam and made in the form of a solid column with grooves, in which, each for its own part, there are piers in the form of arches with made inside each of them fire channels with openings for the exit of gases into the material layer, supported with a gap, for possible temperature deformations at the joints, one wing on the shaft lining, the other on the central ceramic support, as well as core and peripheral fuel burning devices installed in two tiers, characterized the fact that the lined shaft is enclosed in a metal casing, and its lining is multilayer using lightweight heat-insulating materials, and the top of the gas distribution core located in the furnace firing zone, it is located above the upper tier of the fuel burning devices, the core being laid out of refractory material using a high-temperature binder, while the grooves in which the walls are located are made in the central ceramic support and in the lining of the shaft opposite each other.

Description

The utility model relates to shaft furnaces for firing lumpy materials, for example, limestone, and can be used in metallurgy, building materials industry, soda and sugar.

Known shaft furnaces for calcining lumpy carbonate materials of various capacities, operating on solid, liquid and gaseous fuels, having a heating, burning and cooling zone, a lined shaft enclosed in a metal casing, peripheral and central, peripheral and beam burners, peripheral burners and a gas distribution ceramic core.

By its principle, a counterflow shaft furnace is an almost ideal heat exchange unit - it has three technological zones: a firing zone, where the temperature range is 870-1250 ° C and two utilization zones. In the cooling zone, the physical heat of the finished product is completely transferred to the air entering the combustion in the firing zone, and thus is completely returned to the process. The heat of the gases leaving the firing zone is transferred to the material in the heating zone in the maximum possible amount. The inevitable heat loss in this process is the heat of the exhaust gases having a temperature of 150-300 ° C.

Known shaft kiln for calcining limestone (RF patent No. 2194931, IPC 7 F27B 1/02, 12/20/2002), containing a ceramic core, consisting of piers and a central pillar equipped with metal gas-cooled fixing beams. This furnace has a casing, a mine lining, remote furnaces, water-cooled support beams under the core, a central pillar, gas-cooled fixing beams resting on the furnace casing, walls, grooves in the shaft lining and the central column, into which walls are provided with gaps for thermal expansion.

The known furnace has several disadvantages:

- the presence of metal gas-cooled fixing beams entering the core body (and piers and the central pillar) and weakening it due to various temperature expansions of the metal and ceramics.

- the presence in the firing zone of water-cooled support beams under the core and, as a result, the loss of part of the heat in the firing zone of the furnace with cooling water, the need for a water cycle with chemical water treatment.

Closest to the utility model in technical essence is a shaft furnace for firing bulk materials (RF patent No. 123507, 12/27/2012), containing a cross-shaped gas distribution core including a central ceramic support mounted on an air-cooled beam and made as a solid a column with grooves, in which, on each side, there are arched-shaped piers with heat channels made inside each of them with openings for the exit of gases into the layer of material supported by a gap m for possible temperature deformations at the joints with one wing on the lining of the shaft, the other on the central ceramic support, as well as core and peripheral fuel burning devices installed in two tiers, and as a central ceramic support it includes a solid column with grooves in which each for its part, piers are located, and the gas distribution core is made 2-3 m higher than the upper tier of the fuel burning devices and laid out of refractory material using a SHS mortar.

The known device has several disadvantages:

- core core is 2-3 meters higher than the upper tier; the fuel of the burning devices does not make it possible to fulfill the functions assigned to it - it does not provide a uniform temperature field over the cross section of the furnace in the firing zone.

- in the prototype, the grooves are arranged only in the central ceramic support, however, with possible temperature deformations, gaps are arranged on both sides of the wall both in the support and in the lining of the furnace shaft. In the absence of grooves for the piers in the lining of the furnace shaft, a radial displacement of the wall (wing of the wall) relative to the lining of the furnace shaft is possible during the initial loading of the furnace with bulk material before starting it. Before starting the furnace, lumpy material intended for firing, or other materials indicated, including those in the book of A.V. Monastyrev, Production of lime, is pre-loaded into a cold furnace. (see the book of Monastyrev A.V. “Production of lime.” M.: Higher School, 1971). With a radial displacement of the wall, gaps designed to compensate for thermal expansions are selected, and when the lining is heated and the temperature elongations of the wall, the lining of the furnace shaft and the wall itself can be destroyed;

- the practice of using SHS mortars as a binder for laying from refractory materials, both the furnace shaft lining and the core, showed the need for preliminary heating of the lining laid on SHS mortars, after 900 ° С, before putting the furnace into operation, to create conditions to ensure the occurrence of reactions of self-propagating high-temperature synthesis (SHS). In self-propagating high-temperature synthesis, the individual elements of the lining (refractory bricks, blocks) are welded into a monolith. The need for this event leads to a significant increase in the cost of construction, reconstruction, and repair of furnaces since It requires the construction of a temporary - "false" arch, the organization of a temporary, different from the regular smoke removal system and a significant additional consumption of process fuel.

The task to which the technical solution is directed is to ensure the mechanical strength and durability of the core, and to reduce the capital and operating costs of the furnace.

This object is achieved in that the shaft furnace for firing lump materials includes a lined shaft with heating, firing and cooling zones, contains an air-cooled beam with windows for supplying cooling air to the furnace space located in the cooling zone, a cross-shaped gas distribution core including a cross-section in cross section, including a central ceramic support mounted on an air-cooled beam and made in the form of a solid column with grooves, in which, for each side, there are piers form arches made within each flue channels with holes for outlet of gases in the layer of material resting with play for possible deformations of a thermal joining locations, one wing on the shaft lining, the other - the central ceramic support. Core and peripheral fuel burning devices are installed in two tiers. In this case, the lined shaft is enclosed in a metal casing and its lining is multilayer using lightweight heat-insulating materials, and the top of the gas distribution core located in the furnace firing zone is higher than the upper tier of the fuel of the burning devices, and the core is laid out of refractory material using a high-temperature binder, in addition, the grooves in which the walls are located are made not only in the solid pillar of the central ceramic support, but also in the lining of the shaft yz opposite to each other, and can be applied gaseous, liquid and solid pulverized fuel furnace for heating.

The claimed combination of significant differences provides the following advantages of the proposed model:

- the presence of a metal casing allows the lining of the shaft furnace to apply heat-insulating fibrous materials between the casing and the working layer of the lining with their fastening to the furnace casing, as well as lightweight heat-insulating materials and filling heat-resistant foam and aerated concrete lightweight, which allows to reduce heat losses through the casing furnaces without a significant increase in the thickness of the lining. In addition, the presence of the furnace casing allows you to fix the necessary equipment and sites on it.

- the core is located in the firing zone, and its top is above the level of the upper tier of fuel combustion devices, which allows you to perform the functions assigned to it - ensuring a uniform temperature field over the cross section of the furnace in the firing zone. The location of the core top above the level of the upper tier of fuel combustion devices in the zone of the furnace with lower temperatures protects the top of the core and, accordingly, the core itself from destruction. In addition, the prototype is a shaft gas furnace, and in the inventive utility model can be used gaseous, liquid and solid pulverized fuel.

- the construction of grooves for the walls in the lining of the furnace shaft eliminates the possibility of radial displacement of the wall (wing of the wall) relative to the lining of the furnace shaft during the initial loading of the furnace with bulk material before starting it and avoids the destruction of the lining and the wall itself under temperature deformations.

The essence of the proposed device is illustrated by drawings, which depict:

figure 1 - firing zone, section aa;

figure 2 - firing zone, section BB;

figure 3-zone firing, section bb

A shaft furnace has: a furnace cover 1, a furnace shaft 2, a furnace lining 3, a gas distribution core 4, core walls 5, fire channels of the core 6, openings in the core for the exit of combustion products into the material layer 7, an air-cooled support beam with a central air supply unit for cooling 8, windows through which cooling air is supplied to the space of the furnace 9, the central ceramic support 10, remote furnaces 11, peripheral diffusion burners 12, air inlet fittings to the lime receiving hopper 13, unloading device 14.

A shaft furnace equipped with a core laid out of refractory material works as follows. Lump material coming from the furnace heating zone is distributed by core into four sectors, where it is burned with fuel combustion products coming from holes 7, walls 5 and peripheral burners 12. The temperature difference in the burning zone along the furnace section is 50-60 ° C according to experimental data that allows you to achieve a degree of firing of 94-96%.

Technical and economic advantages of the proposed technical solutions are as follows:

- increased mechanical strength and durability of the core;

- reduced capital and operating costs for firing materials;

- reduced the likelihood of destruction of the walls and lining of the shaft of the furnace during thermal deformations.

Claims (1)

A shaft furnace for calcining bulk materials, comprising a lined shaft with heating, calcining and cooling zones, an air-cooled beam with windows for supplying cooling air to the furnace space located in the cooling zone, a gas distribution core cross-shaped in cross section, including a central ceramic support mounted on an air-cooled beam and made in the form of a solid column with grooves, in which, each for its own part, there are piers in the form of arches with made inside each of them fire channels with openings for the exit of gases into the material layer, supported with a gap, for possible temperature deformations at the joints, one wing on the shaft lining, the other on the central ceramic support, as well as core and peripheral fuel burning devices installed in two tiers, characterized the fact that the lined shaft is enclosed in a metal casing, and its lining is multilayer using lightweight heat-insulating materials, and the top of the gas distribution core located in the furnace firing zone, it is located above the upper tier of the fuel burning devices, the core being laid out of refractory material using a high-temperature binder, while the grooves in which the walls are located are made in the central ceramic support and in the lining of the shaft opposite each other.

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