RU2127317C1 - Design of blast-furnace shaft - Google Patents

Abstract

FIELD: ferrous metallurgy, in particular, designs of blast furnaces; may be used in construction of blast furnaces. SUBSTANCE: invention consists in that used in shaft are large panels with cooled pipes. To reduced number of holes in jacket, pipes are arranged by pipe-in-pipe manner through the entire height of shaft. Down pipe is installed on threaded joint, and bottom of rising pipe is lowered into hollow steel sleeve whose height equals two diameters of pipe. EFFECT: high gas tightness of jacket and full compensation of temperature stresses in cooled pipes. 1 dwg

Description

 The invention relates to ferrous metallurgy, in particular to blast furnace production.

 At present, instead of traditional cast-iron stove refrigerators, mine blast furnaces are equipped with large-block panels or refrigerators from thick-walled steel pipes with an annular space filled with refractory mass.

 A design is known in which brackets of steel pipes are installed between the casing and the masonry. These staples with the upper and lower ends are discharged through the casing of the furnace and welded with a strong, dense seam. The holes of the pipes in the casing are arranged in a “spacing” to reduce the weakening of the casing [1].

 A patent is also known [2], where the authors propose assembling a blast furnace shaft from large-block panels with cooled pipes to the entire height of the cooled part of the shaft, in which the lowering pipe passes inside the lift, fixed by sliding supports that allow vertical movement of this pipe.

 The latest design is taken as a prototype.

 The known solution has the following disadvantages.

 In cooled pipes, breaks can occur due to thermal expansion and leakage can occur. Water entering the mine threatens to stop the furnace for repairs.

 In order to eliminate these shortcomings, the design of a large-block panel, shown in the drawing, is proposed. This panel includes a part of the shaft casing. The width of the large block panel is from 1/6 to 1/8 of the circumference of the furnace casing. The height of the panel is equal to the height of the cooled shaft and ranges from 10 to 12 m. Along the large-block panel, steel pipes are installed, made by the type "pipe in pipe". Thus, the length of these pipes is 10 - 12 m. The pipes are introduced through holes in the casing in the upper part to the very bottom of the shaft (to the moratorium).

 The cooling system is assembled as follows. Along the casing of the furnace 1, a lifting pipe 2 is installed with its lowering pipe 3 inserted inside. The output of the lifting pipe through the casing is made through a pipe 4, inside of which a pipe 5 is located, connecting a lowering pipe 3 to the circulation circuit. A sharp bend of the lowering pipe 3 when combined with the pipe 5 made using square 6 on a screw thread. The dimensions of the square are such that it is placed inside the riser pipe. The top of the lifting pipe is sealed with a plug 7, and the bottom of the plug 8. The lower pipe is not brought to the stop (plug 8) by a value of 1 - 1.5 diameters. To the bottom of the shaft (moratorium) the lifting pipe is not brought up to 1.5 - 2.0 diameters for freedom of thermal movement and is fixed at the bottom with a glass 9, a height of 2 pipe diameters. To fix the pipe along its length (shaft height), several sliding supports are installed that allow movement only along the axis. Such pipes are installed along the entire casing at a distance (between the axes) of 250 - 350 mm.

 The space between the casing and the pipes is filled with a refractory mass. The technology of its application depends on the technology of assembly of the casing. In case of block manufacture of the casing, the mass is applied to individual blocks away from the furnace on a special working platform, and is compacted by vibrators. Between the casing and concrete, a layer of low heat conductive mass can be laid for better thermal insulation of the casing.

 The chilled pipe system forms a shield protecting the casing from heating. The screen tubes are connected to a cooling system (evaporative or water).

 This system works as follows. As the masonry and then the layer of refractory mass (concrete) rises, the thermal load on the chilled pipes increases and, finally, reaches a maximum for the 3rd year of operation. As the experience of operating furnaces with concrete refrigerators has shown, after the destruction of the refractory mass to the format of the chilled pipes, further destruction is suspended until the end of the furnace campaign. The chilled pipes themselves do not wear out during furnace operation and retain their original structure and wall thickness.

 This ensures reliable operation of the mine blast furnace. Thermal deformation of pipes occurs only in the axial direction. Rigid fastening takes place at the entry point; the other end hangs in the glass 9, and no stress can arise.

From the above data it is seen that the proposed design:
1. Provides a minimum number of holes in the casing and, therefore, its increased strength.

 2. It guarantees high gas tightness of the casing, which helps to improve working conditions and a slight decrease in the specific consumption of coke.

 3. Contributes to improved circulation during evaporative cooling, since there are no local resistances in the heated part of the lift path.

 4. Provides full compensation of temperature stresses in the pipes.

Literature
1. RU 2010543A, C 21 B 7/10, 07.25.95.

 2. RU 2064504A, C 21 B 7/10, 07.27.96.

Claims (1)

 The device of the blast furnace shaft, including large-block panels with chilled pipes, continuous over the entire height of the chilled part of the shaft, in which the lowering pipe passes inside the lifting, fixed by sliding bearings, allowing vertical movement of this pipe, characterized in that the lowering pipe is introduced on a threaded connection, and the bottom of the lifting pipe is lowered into a hollow steel cup with a height of 2 pipe diameters.