JP6323874B2 - Cement baking equipment - Google Patents

Description

  The present invention relates to a cement firing device, and more particularly, to a cement firing device provided with a chlorine bypass system for extracting a portion of combustion gas from a kiln bottom of a cement kiln to remove chlorine.

  In recent years, industrial wastes used as raw materials for cement contain low-melting-point volatile components such as chlorine, sulfur, and alkali, which are circulated and concentrated in the kiln / preheater system, and the bottom of the kiln and the lower part of the preheater. This causes a low melting point compound such as alkali chloride and causes problems such as blockage. Therefore, by extracting a part of the combustion gas from the kiln bottom of the cement kiln and cooling it, the gaseous low-melting-point volatile components, mainly KCl components, are solidified and classified in a cyclone, and the crude KCl concentration is low. The powder is returned to the kiln system, and fine powder enriched with KCl at a high concentration is discharged out of the system to prevent clogging (see, for example, Patent Document 1).

JP 2014-159342 A

  However, in the above chlorine bypass system, when the concentration of the raw material dust contained in the extraction gas is high, the KCl concentration of fine powder obtained by classifying the extraction gas decreases, the KCl concentration of the coarse powder increases, and the low melting point There is a problem that the efficiency of discharging volatile components out of the system decreases.

  Therefore, the present invention has been made in view of the above problems in the conventional cement firing apparatus, and reduces the raw material dust concentration in the bleed gas in the chlorine bypass system and efficiently removes the low melting point volatile components. It is an object of the present invention to provide a cement baking apparatus capable of performing the above.

In order to achieve the above object, the present invention extracts a combustion gas extracted from the cement kiln exhaust gas passage from the bottom of the kiln kiln to the bottom cyclone while cooling a part of the combustion gas. In the cement baking apparatus, a baffle plate is provided below the bleed port for the combustion gas provided in the cement kiln exhaust gas flow path, so as to prevent the material dust that has risen from flowing into the bleed port. When the short diameter of the bleed port is D1, it has a width equal to or greater than the short diameter D1 along the inner wall of the cement kiln exhaust gas flow path in which the bleed port is bored in a top view, and the protruding length from the inner wall Saga, when the L the length of the vertical inner wall with respect to the bleed port inner wall of the cement kiln exhaust gas passage which is bored, characterized in der Rukoto below 1 / 3L.

  According to the present invention, since the baffle plate is provided below the combustion gas extraction port, even if the raw material dust in the extraction gas soars at the bottom of the kiln, the raw material dust is prevented from flowing into the extraction port. It is possible to reduce the concentration of the raw material dust in the extracted gas and efficiently remove the low melting point volatile components. By reducing the amount of extracted gas corresponding to the improved efficiency, it is possible to reduce heat loss while maintaining the waste treatment amount. On the other hand, when the amount of extracted gas is maintained, heat loss cannot be reduced, but the amount of waste processed can be increased.

  In addition, an angle formed between the upper surface of the baffle plate and the inner wall formed above the baffle plate in which the bleed port is formed can be set to 45 degrees or more and 90 degrees or less.

  Furthermore, when the major axis of the bleed port is D2, the upper surface of the baffle plate abuts against the inner wall of the cement kiln exhaust gas flow channel at a position that is 1 / 2D2 or more and 3 / 2D2 or less below the center of the bleed port. It can be constituted as follows.

  As described above, according to the present invention, it is possible to reduce the raw material dust concentration in the extraction gas in the chlorine bypass system, and to efficiently remove the low melting point volatile components.

It is a figure which shows the kiln bottom part of the cement baking apparatus which concerns on this invention, Comprising: (a) is a front view, (b) is a partially broken side view, (c) is the sectional view on the AA line of (b). is there. It is a figure which shows the flow of the cement raw material particle | grains in the kiln bottom part of the cement baking apparatus which concerns on this invention, Comprising: (a) is a front view, (b) is a partially broken side view. It is a figure which shows the flow of the cement raw material particle | grains in the kiln bottom part of the conventional cement baking apparatus, Comprising: (a) is a front view, (b) is a partially broken side view. It is a figure for demonstrating the cause for the raw material dust density | concentration contained in extraction gas becoming high in the conventional cement baking apparatus, Comprising: (a) is a front view, (b) is a partially broken side view.

  Next, modes for carrying out the present invention will be described with reference to the drawings.

  FIG. 3 shows a kiln bottom part of a conventional cement firing device. The cement kiln 2 has a rising duct (from the kiln bottom of the cement kiln 2 to the lowermost cyclone) connected to the upper calciner through the inlet hood 6. A part of the cement kiln exhaust gas flow path) 3 is connected, and the rising duct 3 is provided with a raw material chute 4 from the uppermost lower cyclone and a probe 5 for extracting a part of the combustion gas. . The rising duct 3 is provided with a material supply port 4 a from the material chute 4 and a bleed port 5 a for bleed by the probe 5.

  In this kiln bottom, a cement raw material (hereinafter referred to as “raw material”) R is supplied from the raw material chute 4 through the supply port 4 a to the cement kiln 2 and fired in the cement kiln 2. The section rides on the combustion gas flow at the kiln bottom and flows in the direction indicated by the arrow.

In the normal state, the present inventors have not so much the amount of the raw material R flowing on the calciner side along with the combustion gas flow, and the dust concentration in the combustion gas extracted by the probe 5 is not high. The present inventors have found that the raw material dust concentration in the cement bleed gas becomes high due to the three factors shown in FIG. That is, as shown in FIG.
(1) When the coating C is generated in the lower portion of the inlet hood 6, the raw material R from the raw material chute 4 is prevented from entering the cement kiln 2, soars into the rising duct 3, and is sucked from the extraction port 5a. .
(2) The raw material flow path (slope) 3b from the supply port 4a of the raw material chute 4 to the inlet of the cement kiln 2 has a step or the like, and if it is not smooth, the raw material R from the raw material chute 4 rises inside the rising duct 3 The air is sucked from the extraction port 5a.
(3) When the rotational speed of the cement kiln 2 is above or below a certain range, the raw material R does not smoothly flow into the cement kiln 2 but rises into the rising duct 3 and is sucked from the extraction port 5a.

  FIG. 1 shows an embodiment of a cement firing device according to the present invention. This cement firing device 1 is provided below a bleed port 5a for bleed by a probe 5 formed in a rising duct 3. The baffle plate 7 is provided to suppress the raw material R soaring as described above from being sucked into the extraction port 5a.

  The baffle plate 7 can be formed, for example, by applying a refractory. As shown in FIG. 1A, the angle θ with respect to the inner wall 3a of the rising duct 3 is set to 45 degrees or more and 90 degrees or less. Further, as shown in FIG. 1 (c), the dimensions of the inner wall 3a are L1 (length of the inner wall in the axial direction of the cement kiln 2) and L2 (inner wall in the direction perpendicular to the axial direction of the cement kiln 2) when viewed from above. The length of the baffle plate 7 (the dimension of the rectangular portion protruding from the inner wall 3a regardless of the angle θ) is shorter than the short diameter D1 of the elliptical extraction port 5a. The diameter D1 is not less than L1 and the short side b is set to (L2) / 3 or less. Further, the mounting height L of the baffle plate 7 (the distance from the center of the bleed port 5a to the position where the upper surface of the baffle plate 7 abuts against the inner wall 3a) is from the center of the bleed port 5a to the long diameter D2 of the bleed port 5a. The position is set at a position lower than 1/2 times and lower than 3/2. These angles θ and the dimensions a and b of the baffle plate 7 and the mounting height L are appropriately changed according to the flow state of the raw material dust in the extraction gas into the extraction port 5a. In addition, the attachment position of the probe 5 and the baffle plate 7 is not limited to FIG.1 (c), Any of the perimeter of the rising duct 3 may be sufficient.

  By providing this baffle plate 7, as shown in FIG. 2, the flow of the combustion gas and dust flowing into the rising duct 3 from the cement kiln 2 can be changed so as to be separated from the extraction port 5a. As a result, the dust in the combustion gas flows in a direction away from the extraction port 5a due to the inertial force, the amount of dust sucked into the extraction port 5a can be reduced, and the raw material dust concentration in the extraction gas can be reduced. it can.

DESCRIPTION OF SYMBOLS 1 Cement baking apparatus 2 Cement kiln 3 Rising duct 3a Inner wall 3b Raw material flow path 4 Raw material chute 4a Supply port 5 Probe 5a Extraction port 6 Inlet hood 7 Baffle plate

Claims (3)

In the cement firing device that extracts the combustion gas from the cement kiln exhaust gas passage from the bottom of the kiln kiln to the bottom cyclone while cooling a part of the combustion gas, and processes the extracted combustion gas,
A baffle plate is provided below the bleed port for the combustion gas provided in the cement kiln exhaust gas flow path to prevent the soaring material dust from flowing into the bleed port ,
The baffle plate has a width equal to or greater than the short diameter D1 along the inner wall of the cement kiln exhaust gas flow path in which the extraction port is bored in a top view when the short diameter of the extraction port is D1. length of projection from the inner wall, when the L a length of the vertical inner wall against the inner wall of the cement kiln exhaust gas passage to the bleed ports are bored, characterized in der Rukoto below 1 / 3L Cement baking equipment. And the upper surface of the baffle plate, to claim 1, wherein the extraction port is the angle between the inner wall located above the baffle plate a inner wall drilled and equal to or less than 90 degrees 45 degrees The cement baking apparatus as described. When the major axis of the bleed port is D2, the upper surface of the baffle plate is in contact with the inner wall of the cement kiln exhaust gas flow path at a position 1 / 2D2 or more and 3 / 2D2 or less below the center of the bleed port. The cement baking apparatus according to claim 1 or 2 , characterized in that

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