RU2456520C2 - Rotary furnace for preparation of cement clinker (versions) - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: rotary furnace for preparation of cement clinker contains a housing resting on the support rollers via bandages, a double drive consisting of two electric motors and two gearboxes, two sub-ring gears, one crown wheel, a feed pipe for sludge supply, a head for supply of fuel and air into the furnace, an iterative preheater, heat exchangers, a grate-pushing refrigerator and equipped with a device for water cooling and a central lubrication system. The housing is made along the perimetre as a multiple-thread helical surface with helical lines along the perimetre and spiral grooves inside the housing at an angle of 3.5-4% with centres of curvature of the helical surface located outside or inside of the cross-section of the housing, is assembled from individual flat elements folded in a vertical plane in a longitudinal direction with respect to its axis of symmetry and curved along a helical line in a transverse direction, while the housing rotates at a speed of 0.5-1.5 rev/min providing a snowballing process of sludge moving in it. Also there is the other description of a design of rotary furnace for preparation of cement clinker.

EFFECT: increased intensity of heat transfer and simplified operation of a rotary furnace at its horizontal position.

2 cl, 9 dwg

Description

The invention relates to a device for producing cement clinker and can be used in the cement industry.

Known rotary kiln for firing bulk material (ed. Certificate No. 1322051, class F27B 7/16, 01/07/86), containing heat exchangers and a screw insert located in the working space of the furnace and equipped with a helical ring and brackets, the plane of which is directed along forming a furnace, moreover, a screw insert is fixed on one side of the bracket and a screw ring on the other side, and the screw ring is fixed at an angle to the radial direction of the furnace, and the screw insert is fixed in front of the heat exchangers, counting during the movement of gases.

A disadvantage of the known device is the lack of heat transfer and limited technological capabilities.

Known rotary kiln for the preparation of cement clinker (Komar A.G. / Building materials and products // A.G. Komar / textbook. Higher school, 1988. S. 147-148), containing a cylindrical body, resting through the bandages on the support rollers , a double drive, consisting of two electric motors and two gears, two gears, one ring gear, a feed pipe for the supply of sludge, a head through which fuel and air are fed into the furnace, a chain filter, a heater, heat exchangers, and a grate-cooler. The housing has a slope of 3.5-4% and is equipped with a water cooling unit and a central lubrication system.

A disadvantage of the known rotary kiln for clinker preparation is the need to create a slope for transporting sludge from loading to unloading, the difficulty in its operation, insufficient heat exchange rate and limited technological capabilities.

The technical solution to the problem is to expand technological capabilities, simplify operation due to the lack of bias.

The technical solution is achieved by the fact that in the first embodiment, in a rotary kiln for the preparation of cement clinker, comprising a housing supported through shafts on the support rollers, a double drive consisting of two electric motors and two gearboxes, two gears, one crown wheel, a feed pipe for feeding sludge, a head for supplying fuel and air to the furnace, a chain filter heater, heat exchangers, a grate-repulsive cooler, and equipped with a water cooling unit and a central system grease, the housing is made around the perimeter in the form of a multiple helical surface with helical lines along the perimeter and screw grooves inside the housing at an angle of 3.5-4% with the centers of curvature of the screw surface located outside or inside the cross section of the housing, mounted from individual flat rolled elements in a vertical plane in the longitudinal direction relative to the axis of symmetry of the strip and curved in a helical line in the transverse direction, while the body rotates at a speed of 0.5-1.5 rpm, providing I am an avalanche-like process of sludge movement in it, according to the second variant, in a rotary kiln for the preparation of cement clinker, comprising a housing resting on the support rollers through shafts, a double drive, consisting of two electric motors and two gearboxes, two gears, one crown wheel, a feed pipe for the supply of sludge, a head for feeding fuel and air to the furnace, a chain filter heater, heat exchangers, a grate-cooler, and equipped with a unit for water cooling and central th lubrication system, the housing is mounted from helical strips of a curvilinear shape of various orders and degrees of curvature with centers located outside or inside the cross section of the housing to form a multiple helical surface with helical lines around the perimeter and helical grooves inside the housing with an angle of inclination of 3.5-4% while the body rotates at a speed of 0.5-1.5 rpm, providing an avalanche-like process of movement of sludge in it.

According to the patent literature not found a technical solution similar to the claimed, which allows to judge about the inventive step of the proposed design of a rotary kiln for the preparation of cement clinker.

The novelty lies in the fact that such a structural design of the casing allows for smooth axial movement of sludge from loading to unloading with a horizontal axis of rotation of the casing, which simplifies operation due to the lack of slope of the casing.

The novelty lies in the fact that due to the internal helical surfaces of double curvature, the vectors of the speed of movement of the sludge change during transportation from load to unload, which contributes to the intensification of heat transfer and expands technological capabilities.

The novelty of the proposal also lies in the fact that inside the screw case with a complex inner surface in the form of a combination of two curved surfaces at each point there are multidirectional components of the movement, which intensifies heat transfer processes and expands technological capabilities.

Figure 1 shows a General view of a rotary kiln for the preparation of cement clinker: figure 2 is a casing, side view: figure 3 is a view a in figure 2; figure 4 is one of the stripes of constant width from which the body is made according to the 1st embodiment after twisting in a vertical plane in the longitudinal direction relative to the axis of symmetry of the strip: in figure 5 is a strip of constant width according to 1 embodiment after bending along helical lines on cylindrical mandrel; in Fig.6 is a section aa in Fig.5: in Fig.7 is a section aa in Fig.5 with the alignment of the edges of two strips; in Fig.8 is a section bB in Fig.2, the helical stripes according to the 2nd embodiment are described by concave-shaped curves, in which the centers of curvature are located outside the cross section of the housing; Fig.9 is a section bB in Fig.2, the helical stripes according to the 2nd embodiment are described by convex curves, in which the centers of curvature are located inside the cross section of the housing.

The rotary kiln for the preparation of cement clinker consists of a housing 1, supported through shafts 2 on the support rollers 3. Housing 1 is mounted horizontally and rotates at a speed of 0.5-1.5 rpm, providing an avalanche-like process of movement of sludge in it. The furnace’s drive is double and consists of two electric motors 4, two gears 5, two gears and one crown wheel 6. In the middle of the furnace, on one of its supports, a pair of rollers is installed (horizontally) to control the displacement of the furnace along the axis (down or up 1) are not shown in FIG. The auxiliary drive is included in the repair of the furnace, during ignition and stop, when the furnace should rotate slowly. The rotary kiln is equipped on one side with a feed pipe 7 for supplying sludge to the housing 1, and on the opposite side with a head 8 for supplying fuel and air. From the side of head 8, fuel and air are supplied to the furnace: as a result of fuel combustion, hot gases are obtained, the flow of which is directed from the hot end of the furnace to the cold end, towards the moving material. To improve heat transfer and dust removal of gases inside the furnace, a chain filter heater 9 is placed in its cold end, a chain curtain 10 is created and heat exchangers 11 are installed in the hopper, and from it using a peripheral loader 12 is sent to the hollow part of the furnace located next to the chain curtain sides of the hot end. To cool the clinker 1, the furnace is equipped with a grate-repulsive refrigerator 14. On furnaces 185 m long, the housing 1 in the sintering zone is equipped with a water cooling unit 15 and a central lubrication system 16.

The housing 1 (Fig.2, 3) according to the 1st embodiment is made around the perimeter in the form of a multiple helical surface with helical lines around the perimeter and helical grooves at an angle of 3.5-4% with centers of curvature located outside or inside the cross section of the housing 1 (Fig. 8, 9) and is mounted from five or more stripes 17, 18, 19, 20, 21 of rectangular shape of the same width along the entire length, rolled up in a vertical plane in the longitudinal direction relative to the axis of symmetry of the strip, for example, strip 17 (Fig. 4) and curved in a helical line in the transverse direction on a cylindrical mandrel 22 (Fig.5, 6). The strips 17, 18, 19, 20, 21 after bending are connected to each other by the lateral sides by known methods, for example by welding (Fig. 7), with the formation along the perimeter of a multi-starting helical surface with helical lines and helical grooves around the perimeter with an inclination angle of 3.5 -4% and with one direction directed at a constant length step S ₁ . One of the helix lines is shown in FIG. 2 with a thickened line 23-24.

The housing 1 according to the 2nd embodiment can be made around the perimeter in the form of a multiple helical surface with helical lines along the perimeter and helical grooves at an angle of 3.5-4% (Fig.2, 3) with centers of curvature located outside or inside the cross section case 1 (Fig. 8, 9) and is made unidirectional, hollow screw around the perimeter of five or more rolled in a vertical plane and sequentially interconnected along the length of the drum strips 17, 18, 19, 20, 21 curved concave shape (Fig. 8 ) or convex shape (Fig. 9) relative to the axis of the rotation rotation of the drum and described by curves of various orders and degrees of curvature, for example, lines of the second order of curvature:

- an ellipse x ² / a ² + y ² / b ² = 1;

- parabola y ² = 2 * p * x;

- hyperbola y = k / x;

Lines of the third order of curvature and higher:

- Cartesian leaf x ³ + y ³ -3 * a * x * y = 0;

- Agnesi curl y = a ³ * (α ² + x ² );

- stanoid y ³ = x ² (a + x) / (a-x);

- Pascal snail (x ² + y ² -2R * x) ^{2-a 2} * (x ² + y ² ) = 0, etc .;

and lines of the nth order of curvature - polynomials.

After bending, the strips 17, 18, 19, 20, 21 are connected to each other by the lateral sides by known methods, for example, by welding, with the formation of a multiple helical surface along the perimeter with helical lines and helical grooves inside the housing with an inclination angle of 3.5-4% and with directed in one direction by a constant step in length S ₁ . One of the helix lines is shown in FIG. 2 with a thickened line 23-24.

The proposed rotary kiln for the preparation of cement clinker works as follows. The housing 1, mounted horizontally, rotates at a speed of 0.5-1.5 rpm

Sludge is fed into the feed pipe 7 using bucket or volumetric dispensers located at the cold end of the furnace (housing 1). From the side of the head 8, fuel and air are supplied to the furnace (housing 1). As a result of fuel combustion, hot gases are obtained, the flow of which is directed from the hot end of the furnace (housing 1) to the cold, towards the moving material - sludge. The sludge inside the rotating housing 1, carried away by its curved helical surfaces, rises up and, rising in the direction of rotation of the housing 1 slightly above the angle of its natural slope, rolls down like an avalanche. Since the multi-screw surface of the housing 1 with helical lines around the perimeter is located at an angle of inclination of 3.5-4%, the slurry when rolling down is directed at the same angle to the axis of rotation of the housing 1, which ensures the movement of sludge along helical lines inside the housing 1 and moving it from loading to unloading with a horizontal arrangement of the housing 1. The filter-heater 9 improves heat transfer and dedusts gases. The dust collected behind the furnace as a result of gas cleaning is returned to the furnace. It is transported by a pneumatic pump to the hopper, and from it, using the peripheral loader 12, is sent to the hollow part of the furnace, located next to the chain curtain from the hot end. The clinker is cooled in a grate-cooler 14.

Technical and economic advantages arise due to the creation on the inner surface of the casing of smooth helical grooves and internal surfaces of double curvature, which not only expands the technological capabilities and ensures the movement of sludge from loading to unloading with a horizontal axis of rotation of the furnace body, but also increases the heat transfer rate and simplifies operation of a rotary kiln with its horizontal arrangement.

Claims (2)

1. A rotary kiln for the preparation of cement clinker, comprising a housing supported through shafts on the support rollers, a double drive consisting of two electric motors and two gears, two gears, one crown wheel, a feed pipe for feeding sludge, a head for supplying fuel to the furnace and air, a chain filter-heater, heat exchangers, a grate-cooler and equipped with an installation for water cooling and a central lubrication system, characterized in that the housing is made around the perimeter in the form of a multiple helical surface with helical lines around the perimeter and helical grooves inside the housing at an angle of 3.5–4% with the centers of curvature of the helical surface located outside or inside the cross section of the housing, mounted from individual flat elements rolled in a vertical plane in the longitudinal direction relative to the axis of symmetry of the strip and curved along the helix in the transverse direction, while the body rotates at a speed of 0.5-1.5 rpm, providing an avalanche-like process of movement in sludge. 2. A rotary kiln for the preparation of cement clinker, comprising a housing supported through shafts on the support rollers, a double drive, consisting of two electric motors and two gears, two gears, one crown wheel, a feed pipe for feeding sludge, a head for supplying fuel to the furnace and air, a chain filter-heater, heat exchangers, a grate-cooler and equipped with a water-cooling unit and a central lubrication system, characterized in that the housing is screw-mounted of curved stripes of various orders and degrees of curvature with centers located outside or inside the cross section of the housing with the formation of a multi-helical surface with helical lines around the perimeter and helical grooves inside the housing with an angle of inclination of 3.5-4%, while the housing rotates at a speed 0.5-1.5 rpm, providing an avalanche-like process of movement of sludge in it.

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