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Selection and construction points of refractory materials for combustion chambers of top-fired hot blast stoves
Jan 08, 2019

The construction of refractory materials for top-fired hot blast stoves can be divided into four parts, namely maze masonry, air and gas ring cavities, straight arch sections and hot air outlet masonry and vault masonry. The main configuration of the refractory materials of these four parts can be referred to FIG. The specific construction masonry points are as follows:


(1) Maze masonry


According to the center elevation of the combustion air tube, the control level of the top of the labyrinth is calculated downward, combined with the relevant dimensions of the drawing surface, taking into account the actual elevation, levelness and pre-swing size of the brick panel, determining the thickness of the screed layer of the brick casting material, and The maze brick control line is released on the sprayed layer.


Control the size of the probe of each layer of the labyrinth brick to the furnace body, pay attention to the layer when constructing the inner and outer ring bricks of the furnace, strictly control the size of the sliding joint between the regenerator wall and the labyrinth (30mm), and fill the refractory ceramic fiber blanket.


(2) Air and gas ring cavity masonry


When laying the first layer of air ring cavity, it is necessary to check the seam along the ring of the furnace body (to prevent the occurrence of processing bricks), ensure that the brick joint is ≤ 2mm, the inner diameter of the furnace body meets the design requirements (6620mm), and the radius wheel rod is used for inspection. Check if the arc degree and the inner diameter of the furnace are within the allowable range (±15mm). According to the center elevation of the air pipe, the control layer is controlled by 3 layers on the spray layer to release the air and gas ring cavity brick control line; the inner and outer ring walls of the air and gas ring cavity should be leveled, otherwise the over-top brick is prone to triangular seams.


Before the entrance of the air and gas pipelines, a stainless steel protection plate with δ=3mm is required, which consists of two halves and is welded to the installation position. Between the gas ring cavity and the air passage, the vertical winding of the furnace is carried out—the layer is δ=0.3mm thick 1Cr18Ni9Ti stainless steel sealing plate; on the air ring cavity over the top brick, the two layers are δ=0.3mm thick 1Cr18Ni9Ti stainless steel sealing plate, its purpose is to prevent air and gas leakage caused by explosion, stainless steel plate at the same time sliding, so the part of the refractory masonry mortar must be full and tight.


When constructing the annular passage of air and gas ring cavity, firstly determine the burner position by the central angle of the combustion chamber and the design elevation, and then adjust the brick joint (1~3mm) by the brick to make the burner burner form and then along the furnace body. The circumference of the ring is evenly arranged. When the air and gas ring chambers are built, the inner ring of the ring cavity is firstly built, and the verticality, flatness and the distance between the rings are controlled by the ruler and the central wheel bar. The error of the adjacent elevation of the inner and outer ring walls is not more than 5 mm. If the outer ring wall is 5mm more than the sprayed layer, fill it with spray paint.


After the burner is built, the air, gas passage and its annular cavity must be thoroughly cleaned. After passing the inspection, the burner is sealed and protected against damage and debris such as broken bricks.


(3) Straight section of the dome and hot air outlet masonry


According to the elevation of the hot air outlet center, the brick line of the straight section of the dome is released on the sprayed layer. During masonry, the elevation and level of the lower furnace wall of the hot air outlet (manhole) should be strictly controlled. Within 1 m of the hot air outlet and the manhole, the andalusite bricks are closely attached to the furnace shell, and the center wheel and pipe radius are used. The wheel rods are rounded to the manholes and pipes. The joints are pre-stamped and then the doors are smoothly closed. The elevation, flatness and arc degree of the straight wall under the arched bricks must be strictly controlled.


In the construction, the hot air branch pipe masonry should be arranged in advance, so as not to affect the masonry progress of the straight section wall. Firstly build the lower semi-circular lightweight clay brick of the hot air branch pipe. After the radius wheel bar is rounded, build the second layer of light high-alumina brick. Leave the expansion joint according to the design requirements. The position and size must be set correctly and used. Andalusite bricks are pressed.


The hot air outlet adopts composite brick masonry (see Fig. 3), and the lower straight wall is successively staggered into the furnace in 4 layers, each floor is 34mm, and then the lower semicircle center wheel rod is controlled to control the radius, and the petal bricks are built in order. Outer ring bricks and inner ring bricks, the inner half of the bricks (working layer), outer ring bricks and petal bricks are laid in order. Between the hot air branch pipe and the hot air outlet combination brick, after casting the steel fiber castable in the lower semicircle, the lower semicircular inner ring brick is built, and the upper semicircle and the two ring bricks are designed with a 50 mm expansion joint and filled with a fiber blanket. The top of the vault is flattened with a rigid fiber castable, and after two sets of staggered bricks (size: 53mm+64mm), the center of the furnace is used to find the circle, and the transition section of the cone is filled with the insulation cast material. real.


(4) vault masonry


The height and flatness of the straight wall of the arch brick must meet the design requirements. After the internal inspection of the arched bricks, the position of the arched bricks and the clearance of the grey joints are adjusted so that the grey joints can be ≤2mm and the inner diameter can be achieved. The arched bricks must be close to the shell and spray paint. .


The vaulted bricks should be built according to the brick number. The big head of the bricks must be pointed into the furnace. It is strictly forbidden to build the bricks. The radial joints between the bricks must point to the center of the furnace body to avoid misalignment or triangular seams; every 3 inner ring silicon bricks Put a 5mm expansion joint wood splint, and the silicon brick should be clamped to the expansion joint. Since the vault brick is inclined to the center of the furnace body and shrinks upwards, the inner radius of each ring brick is determined according to the inner radius of the arch height provided by the design (generally given the inner radius of the lower layer of the brick layer), and the center wheel is used. Rod to control.


Each brick of the vault is placed obliquely, which is easy to slide. When the masonry is thickened, the consistency of the mortar should be increased. After the mortar is applied to the brick, it takes a few seconds to go to the wall. At the same time, the bricks are hooked to the silicon bricks. It is only allowed to remove the hook after closing the door. As the inner diameter of the dome becomes smaller, the density of the hooks of the hanging bricks should be increased, and each of the last few bricks must be hooked with brick hooks.


When laying a vaulted brick, it is advisable to support the insert-type arch tire under the cover brick.


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