RU2624245C2 - Method of flux bed building in furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy and other industry sectors where furnaces with liquid flux bed are used. Namely, invention refers to a method of flux bed building in furnaces for Vanukov melting process, Romelt process, waste processing in molten slag, coal gasification in bubbled molten slag. For flux bed building in furnace by fuel combustion flare in work space of the furnace between enclosure structures and bottom, part of solid materials forming slag is fed and molten at the inner surface of furnace enclosure structures above melt level in the flux bed. Temperature at the inner surface of enclosing structures exceeds softening temperature of materials forming slag, containing particles with the size under 1 mm, by 20-100 °C.

EFFECT: reduced time of furnace launch and fuel consumption.

6 ex

Description

The invention relates to metallurgy and other industries that use furnaces with a liquid slag bath. In particular, the invention relates to a method for depositing a slag bath in Vanyukov smelting furnaces, the Romelt process, a waste processing process in a slag melt, coal gasification in a bubbled slag melt.

There is a method of forming a slag bath in furnaces, which consists in pouring a molten liquid in other furnaces of a furnace slag (Melting in a liquid bath. Ed. Vanyukov A.I., M .: Metallurgy, 1988, p. 102).

This method allows you to quickly form a slag bath. However, the implementation of this method requires the presence of other furnaces in which it is possible to melt the slag. If there are no such furnaces, the formation of a slag bath in this way is impossible.

Closest to the proposed invention is a method for fusing a slag bath in a furnace with a liquid slag bath, including the formation of a torch from burning fuel in the working space of the furnace between the enclosing structures and the hearth, the supply of solid slag-forming materials, melting of slag-forming materials (Romelt process. Ed. Romenets V. A., MISIS, 2005, p. 53-55).

Under the building envelope understand the elements of the furnace, separating its inner part from the environment - the walls and the arch of the furnace.

This method allows you to weld a slag bath in a furnace with a liquid slag bath in the event that there are no other furnaces in which you can pre-melt the slag and pour it into the furnace.

However, this method requires a significant start-up time and is associated with significant fuel costs. Significant time and fuel consumption required to start the furnace are explained by the fact that the melting of solid slag-forming materials is carried out on a rather small surface of the hearth of the furnace, on which they are loaded.

An object of the invention is to reduce the start-up time of a furnace with a liquid slag bath and to reduce the fuel consumption used by increasing the surface on which the melting takes place, by melting part of the solid slag-forming materials on the inner surface of the enclosing structures of the furnace.

This problem is solved by the fact that in the known method of fusing a slag bath in a furnace with a liquid slag bath, including the formation of a torch from burning fuel in the working space of the furnace between the enclosing structures and the hearth, the supply of solid slag-forming materials, melting of slag-forming materials, according to the invention, part of the solid slag-forming materials are fed and melted on the inner surface of the enclosing structures of the furnace above the level of the melt in the bath, solid slag-forming materials contain an hour particles less than 1 mm in size, and the temperature on the inner surface of the building envelope exceeds the softening temperature of slag-forming materials by 20-100 ° С.

When a part of the solid slag-forming materials is supplied on the surface of the enclosing structures of the furnace above the melt level in the bath, the melting of solid slag-forming materials is carried out not only on the bottom of the furnace, but also on these surfaces.

In this case, the heat exchange between the torch from burning fuel in the working space of the furnace and melting slag-forming materials is intensified, since the heat transfer from the torch increases with an increase in the heat exchange surface, which ensures an increase in the rate of deposition of the slag bath. The fuel efficiency increases, which ensures a reduction in its consumption.

The supply of slag-forming materials to the inner surface of the enclosing elements of the furnace above the melt level is carried out by mechanical or pneumatic action on the slag-forming materials. For example, by exposing the slag-forming materials to a jet of compressed air or supplying them to a cone-type device.

Slag-forming materials can be both minerals (limestone, quartz, basalt, etc.) in the required ratio, and metallurgical slag.

It was established that if solid slag-forming materials do not contain particles less than 1 mm in size, then they roll down to the bottom of the furnace without even being able to partially melt on the enclosing surfaces of the furnace. In this case, an increase in the surface on which the melting takes place does not occur. Particles with sizes less than 1 mm have time to partially melt and from them on the surface of the enclosing structures of the furnace a semi-liquid layer of slag is formed, to which larger particles are attached. This layer on the enclosing structures flows along them and is an additional surface to the bottom of the furnace, on which the slag-forming materials melt.

The content in the slag-forming materials fraction minus 1 mm can be any. Even their very small content provides the implementation of the mechanism of formation of a semi-liquid slag layer on enclosing surfaces. The higher the particle content of the fraction minus 1 mm, the faster this process.

It is important that the temperature on the surface of the enclosing structures of the furnace be higher than the softening temperature of the slag-forming materials by at least 20 ° C. Otherwise, even particles with sizes less than 1 mm will not have time to partially melt on the surface of the enclosing structures of the furnace and the surface on which the melting is carried out will not increase.

If the temperature on the surface of the enclosing structures of the furnace is higher than the softening temperature of the slag-forming materials by more than 100 ° C, then the rate of run-off of the semi-liquid slag layer on the surfaces of the enclosing structures of the furnace will be so high that the particles of slag-forming materials falling into it will not have time to melt and get in solid form into the slag bath and reduce the start-up time of the furnace and reduce fuel consumption does not occur.

The set temperature on the inner surface of the building envelope is provided by a torch from burning fuel in the working space of the furnace. If the temperature is lower than required, the torch is made more intense and vice versa. The intensity of the torch is regulated by the consumption of fuel and oxidizer.

EXAMPLES OF IMPLEMENTATION

The slag bath is fused in a furnace with a hearth area of 28 m ² .

The amount of slag for forming the slag bath necessary for the technology is 120 tons.

The softening temperature of slag-forming materials is 1100 ° C.

Example 1 (closest method)

Slag-forming materials are fed to the bottom of the furnace in an amount of about 3 tons per hour.

The duration of the formation of the slag bath is 37 hours, the total fuel consumption (natural gas) is 37 thousand m ³ .

Example 2

Slag-forming materials are fed in the furnace in an amount of about 3 tons per hour to the bottom and to the inner surface of the furnace enclosing structures above the melt level in the bath. As slag-forming materials, granulated blast furnace slag is used. The supply of slag-forming materials to the walls of the furnace is carried out by pneumatic impact on them with compressed air jets mainly in the horizontal direction. The consumption of compressed air for pneumatic effects on slag-forming materials is 500 m ³ / hour.

The temperature on the inner surface of the building envelope is 1160 ° С, which is ensured by the torch from burning 1000 m ^{3 of} natural gas per hour, the consumption of oxidizing agent (oxygen) is 1900 m ³ per hour.

Slag-forming materials do not contain particles smaller than 1 mm.

The duration of the formation of the slag bath is 37 hours, the total consumption of natural gas is 37 thousand m ³ .

Example 3

The same as example 2, but the slag-forming materials contain particles smaller than 1 mm in an amount of 0.5% of the supplied slag-forming materials.

The duration of the formation of the slag bath is 32 hours, the total consumption of natural gas is 32 thousand m ³ .

Example 4

The same as example 3, but the temperature on the inner surface of the building envelope is 1110 ° C, which is ensured by the torch from burning 1000 m ^{3 of} natural gas per hour, the consumption of oxidizing agent (oxygen) is 1800 m ³ per hour.

The duration of the formation of the slag bath is 37 hours, the total consumption of natural gas is 37 thousand m ³ .

Example 5

Same as example 4, but slag-forming materials contain particles less than 1 mm in size.

The duration of the formation of the slag bath is 37 hours, the total consumption of natural gas is 37 thousand m ³ .

Example 6

The same as example 2, but the temperature on the inner surface of the building envelope is 1320 ° C, which is ensured by the torch from burning 1000 m ^{3 of} natural gas per hour, the consumption of oxidizer (oxygen) is 2050 m ³ per hour.

The duration of the formation of the slag bath is 37 hours, the total consumption of natural gas is 37 thousand m ³ .

Thus, the application of the invention allows 13.5% to reduce the start-up time of the furnace and fuel consumption.

Claims (1)

A method for depositing a slag bath in a furnace with a liquid slag bath, including the formation of a torch from burning fuel in the furnace working space between the enclosing structures and the hearth, feeding and melting solid slag-forming materials, characterized in that they use solid slag-forming materials containing particles smaller than 1 mm, while part of the supplied solid slag-forming materials are melted on the inner surface of the enclosing structures of the furnace above the level of the melt in the bath, and the temperature on the inner surface ited walling is set above the softening temperature of the slag-forming materials at 20-100 ° C.