Hot blast branch pipe construction method and hot blast branch pipe of blast furnace hot blast stove

Abstract

Provided is a method for constructing a hot-blast branch pipe of a blast furnace hot stove that eliminates the need for expansion joints in order to avoid expansion-joint-related problems of various kinds. In consideration of the thermal expansion difference (d) between a blast furnace body (1) and an upright hot-blast branch pipe section (5) when the temperature of the blast furnace is increased in a dry state, the height of the connecting position of upright hot-blast branch pipe section (5) to the blast furnace body (1) is set higher than the height of the connecting position of the blast furnace body (1) to the upright hot-blast branch pipe section (5) by the thermal expansion difference absorption margin of s = 0.26d - d during the initial installation. By setting the respective lengths of the upright section and horizontal sections of the hot-blast branch pipe three or more times greater than the respective pipe diameters, differences in thermal displacement and the thermal displacements themselves can be absorbed by means of elastic deformation of the pipes themselves. As a result, there is no longer any need for the use of any expansion joints, so expansion-joint-related problems of various kinds can be avoided.

Description

technical field [0001] The invention relates to a hot blast branch pipe in a blast furnace hot blast stove, especially a hot blast branch pipe part that is suitable for connecting a hot blast stove main body and a hot blast main pipe connected to an annular pipe of the blast furnace. Background technique [0002] The hot blast stove, which is an accessory equipment of the blast furnace, is used to heat and raise the temperature of the blown air from the tuyere, and is roughly divided into a small internal combustion type hot blast stove and a large external combustion type hot blast stove. In the external combustion type hot blast stove, the regenerator is separated from the combustion chamber, and the upper dome is connected to each other. Regarding this connection structure, conventionally, an expansion joint made of a corrugated structure called a bellows is interposed to absorb the difference in thermal displacement generated in the heat storage chamber and the combustio...

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Problems solved by technology

[0003] However, in expansion joints made of folded structures, bricklaying is very complex and difficult to build

In addition, in the part where expansion and contraction occurs, in order to absorb the expansion and contraction, it is necessary to build bricks with gaps between bricks, and in the expansion joint part where repeated expansion and contraction has been repeated for many years, the bricks will be worn out, peeled off, and the iron sheet will be red hot. question

In addition, there is also a problem that the folds of the expansion joint itself are damaged due to stress corrosion cracking.

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