SU606068A1 - Shaft furnace - Google Patents

Description

(54)

SHAFT FURNACE

I

The invention relates to solid fuel kilns for firing raw materials and can be used in the chemical, metallurgical industry and building materials industry, in particular, for calcining limestone in the production of ammonia soda.

Wear blast furnaces for burning carbonate raw materials on solid fuel containing a vertical lined shaft with loading and unloading devices and inlets for air supply for combustion l.

The mixture, containing solid fuel and lumpy carbonate raw materials, is loaded from above into the kiln and as it progresses down the PROHD11T successively three technological zones: the preheating, roasting and cooling zones. In the preheating zone, the cold is heated by the products of combustion of solid fuels that form in the burning zone during the combustion of fuel. Below the burning zone there is a cooling zone in which the calcined material is air-cooled, feeding "1M" to the kiln from below. The heated air enters the combustion zone, where oxygen is air-a, a reaction with hot fuel, forms carbon dioxide.

(COj), and in the furnace gas entering the preheating zone, oxygen is either absent or contained in insignificant amounts.

On the border between the burning zone and the heating zone, there is a so-called recovery zone.

in coma

The second high-temperature gas, which practically does not contain oxygen, comes into contact with excess carbon (at t 750-800С) with carbon of the fuel, forming carbon monoxide (CO).

Due to underburning in a furnace of carbon monoxide a significant amount of thermal energy is lost.

In addition, carbon monoxide is poisonous gas and its emissions into the atmosphere have a detrimental effect on the environment.

The known shaft kiln for burning carbonaceous raw material on solid fuel contains a lined shaft, which can be divided into zones of heating, burning and cooling of the material. A reduction zone is located between the preheating and calcining zones, and inlets in the furnace shaft are provided for the supply of air for combustion.

recovery area inside the mine in

The perforated insert for supplying air is not installed with the possibility of vertical displacement of the floor.

A disadvantage of the known device is a relatively small reduction of CO in the furnace gas, which is due to the fact that the furnace insert floor, being mobile, however, cannot be made of large diameter, otherwise it would have a significant resistance to the displacement of the charge it hangs in oltsov space between the insert and lining of the shaft furnace. With a small insert diameter, for example, 1 m or less, it is impossible to supply air from the center to the periphery of the furnace, since a thick layer of the charge (approximately 1.7 m with a charge diameter of 4.5 m) provides significant resistance, and also an ascending tray furnace gases entrains upward air escaping from the perforation of the insert, and prevents its uniform distribution over the shaft section.

As a result, it is impossible to achieve a more complete oxidation of carbon monoxide to carbon dioxide, which leads to an excessive loss of thermal energy.

The aim of the invention is to reduce fuel consumption and CO content in furnace gas.

The goal is achieved by the fact that the proposed oven, comprising a lined housing with air inlets, is provided with a horizontal perforated partition with a doser, under which air inlets are located.

In addition, the dividing wall dosing unit is made in the form of sicTeh & i-moving and fixed grates covered with a layer of catalyst.

FIG. 1 shows the shaft furnace in section; figure 2 - section aa of figure 1.

The shaft furnace contains a vertical lined casing 1, divided conventionally into technological heating zones 2, 3 calcinations and 4 cooling. Between the preheating zone 2 and the burning zone 3 there is a reducing zone 5 in which the high-temperature furnace gas is in contact with the surface of the heated solid fuel. Between the heating zone 2 and the burning zone 3, a perforated dosing baffle is installed horizontally over the reduction zone 5, made, for example, in the form of a system of movable 6 and fixed 7 grates. Under the dosing baffle inputs are made 8 dl

supplying hot air to the cooling zones 4 using the exhauster 9.

The moving grate 6 is connected to the drive 10, with which they can be set in motion in the vertical direction. This increases or decreases the flow area of the perforated partition wall.

Depending on the size of the charge pieces, the speed of its discharge from the furnace, the distance between the moving b and fixed 7 grates and the speed of movement of the moving grate 6 are chosen so that under the dosing partition there is always a space 11 free from the charge above the reduction zone 5 .

Movable 6 and fixed 7 grate, it is advisable to cover with a layer of catalyst that promotes the additional oxidation of CO into CO, for example, by spraying palladium-containing material.

The furnace works as follows.

Through the charging device in the upper part of the furnace (not shown in the drawing), the mixture charged from the lumpy carbonate raw material and solid fuel (coke) is loaded into it. The mixture is held by a dosing partition in the heating zone 2, where it is heated by furnace gases. With the help of the dosing batch, the mixture is fed to the reduction zone 5 and the burning zone 3, where solid fuel is burned and the released heat is consumed, mainly for the dissociation of carbonate of CaCO To CaO CO, j. The firing process takes place at 1000-1300 ° C. The amount of charge supplied to the recovery zone

5 and zone 3 firing, regulate the alternate lifting of the grate

6 using the drive 10 or lowering them depending on the speed of discharge of the charge, the size of the pieces of the calcined material. At the same time, the free space from the charge 11 must have a certain volume, the value of which is adjusted depending on the CO content in the kiln gas, the velocity of the kiln gas and its temperature.

The air from the cooling zone 4 is supplied with the help of the exhauster 9 through the inlets 8 to the space free from the charge, where it is mixed with the CO-containing kiln gas coming from the reduction zone 5, resulting in complete CO afterburning, the amount of hot air, supplied to space 11 should be sufficient to completely burn carbon monoxide in dioxide dioxide.

The heat generated during the afterburning process is transferred to the charge located