JP2006284024A - Rotary kiln type drying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying device capable of uniformly and properly drying a dried object in a drying chamber by unifying a temperature distribution in a cylindrical combustion chamber, and implementing stable drying operation without thermal deformation and mechanical deterioration of the device, in the rotary kiln-type drying device for drying the dried object charged into the drying chamber by the cylindrical combustion chamber mounted at an outer side of the rotary kiln type drying chamber. <P>SOLUTION: This rotary kiln type drying device comprises the rotary kiln type drying chamber rotatable on its axis, the cylindrical combustion chamber coaxially fixed to an outer side of the drying chamber in a state of air-tightly kept into contact therewith, and having a diameter larger than the drying chamber, a fuel supply nozzle and a combustion gas supply nozzle mounted at an inlet side of the cylindrical combustion chamber toward the tangent direction of the inner wall surface of the combustion chamber, a rotating drying mechanism of the rotary kiln type drying chamber, and a dried object supplying device mounted at an inlet side of the drying chamber. By forming uniform tubular flame in the combustion chamber by the fuel and the combustion gas supplied from the nozzles, the combustion chamber is uniformly heated, and the dried object in the drying chamber can be efficiently dried. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotary kiln type drying apparatus capable of stable drying operation.

  For example, in order to reduce moisture content such as coal, drying is performed. A rotary kiln type drying furnace is used as a drying apparatus for such coal and the like. FIG. 3 is a schematic cross-sectional view showing an example of a conventional rotary kiln type drying apparatus. As shown in the drawing, a fixed cylindrical combustion chamber 2 having a larger diameter and a shorter length than the outer diameter of the drying chamber 1 is disposed outside the rotary kiln type drying chamber 1 formed of a horizontal rotary cylindrical furnace. Are provided in coaxial contact with the drying chamber 1 in an airtight manner.

  On the inlet side of the rotary kiln-type drying chamber 1, a dry matter supply device 3 is provided, and on the outlet side, a dry matter discharge port 4 is provided. A plurality of burners 5 are attached to the end surface of the cylindrical combustion chamber 2 at predetermined intervals on the circumference thereof. As the burner 5, for example, a spray type oil burner of a type in which liquid fuel is pressurized and injected at high speed from a spray port, and is atomized to burn is used, and the rotary kiln is heated by the heat of the flame generated by the burner 5. The type drying chamber 1 is heated from the outer periphery. 6 is an exhaust pipe provided on the other end side of the cylindrical combustion chamber 2.

  The rotary kiln-type drying chamber 1 and the cylindrical combustion chamber 2 are inclined downward from the inlet side toward the outlet side, that is, the discharge direction of the dried material. The drying chamber 1 is formed into a cylindrical shape by a drive mechanism (not shown). It rotates slowly around its axis while sliding on the cylindrical combustion chamber 2.

  As a result, the material to be dried 7 such as coal supplied from the inlet side supply device 3 into the rotary kiln type drying chamber 1 moves toward the outlet side outlet 4 while being stirred by the slow rotation of the drying chamber 1. . As described above, the rotary kiln-type drying chamber 1 is heated by the flame sprayed from the plurality of burners 5 of the cylindrical combustion chamber 2 that is in sliding contact with the outer periphery thereof. The object 7 is dried by indirect heating in the cylindrical combustion chamber 2 and discharged from the discharge port 4.

  In such a conventional drying apparatus, a plurality of burners 5 in the cylindrical combustion chamber 2 for heating the rotary kiln-type drying chamber 1 are attached to the inlet side end face of the combustion chamber 2 at predetermined intervals on the circumference thereof. It has been. Therefore, it is inevitable that the flame formed by the burner 5 exists locally.

Patent Document 1 discloses a scrap preheating furnace in which a tubular flame burner is provided in a tubular combustion chamber as a scrap preheating furnace for preheating a scrap steel material in a normal temperature state.
Further, in Patent Document 2, a gas burner is attached on the outlet side of the rotary kiln so as to be opposite to the moving direction of the combustion treatment product, and further, the gas burner can be moved and swung in a three-dimensional direction. A mechanism is disclosed.
JP 2004-69266 A JP 2001-304764 A

  As described above, in the conventional rotary kiln drying apparatus, the cylindrical combustion chamber 2 for heating the rotary kiln-type drying chamber 1 has a burner 5 at a predetermined interval on the circumference thereof at the end surface on the inlet side of the combustion chamber 2. Therefore, the flame by the burner 5 exists locally. As a result, the inside of the drying chamber 1 cannot be heated uniformly over the entire cross section and longitudinal direction, and therefore, the temperature of the object to be dried 7 in the drying chamber 1 is not easily raised and dried.

The spray-type oil burner generally used as a combustion oil burner is a system in which liquid fuel is pressurized and injected at a high speed from a spray port, and is atomized and burned. A flame is formed in front of the tip.
Therefore, the temperature distribution in the cylindrical combustion chamber 2 is biased, and the problem arises that the inlet side, that is, the inlet side of the rotary kiln-type drying chamber 1 where the material to be dried 7 is deposited, has a lower temperature than other portions.

  Therefore, when a rotary kiln type drying apparatus is used, a temperature sufficient to raise the temperature of the material to be dried 7 inside the cylindrical combustion chamber 2 before putting the material to be dried 7 into the drying chamber 1. It is necessary to heat up to. Furthermore, as a result of the temperature distribution in the cylindrical combustion chamber 2 being biased, the entire apparatus is thermally deformed at a high temperature portion, and there is a problem that mechanical deterioration is likely to occur.

  Further, the technique disclosed in Patent Document 1 is a furnace for preheating scrap, in which the scrap is charged into a combustion chamber in which a preheating burner is installed, and the flame from the preheating burner is directly blown onto the scrap. This is to preheat this, and the material to be dried in the kiln 1 is not indirectly dried by the cylindrical combustion chamber 2 provided outside the rotary kiln 1 as in the present invention.

  The technique disclosed in Patent Document 2 is effective in increasing the combustion temperature in the rotary kiln furnace, particularly in the latter stage of the furnace, but as a result of the complicated flow of gas on the inlet side and outlet side, the inside of the drying chamber 1 is increased. The question remains whether it can be heated uniformly.

  Accordingly, an object of the present invention is to provide a temperature distribution in a cylindrical combustion chamber in a rotary kiln type drying apparatus that dries an object to be dried charged in a drying chamber by a cylindrical combustion chamber provided outside the rotary kiln type drying chamber. The rotary kiln type can dry the objects to be dried in the drying chamber uniformly and accurately, and can perform a stable drying operation without causing thermal deformation or mechanical deterioration in the entire apparatus. It is to provide a drying apparatus.

  The rotary kiln-type drying apparatus according to the first invention is fixed to the rotary kiln-type drying chamber that is rotatable about its axis, and to the outside of the rotary kiln-type drying chamber so as to be coaxially and airtightly contacted with the drying chamber. A cylindrical combustion chamber having a diameter larger than that of the drying chamber, a fuel supply nozzle for injecting fuel into the combustion chamber, provided on the inlet side of the cylindrical combustion chamber toward the tangential direction of the wall surface of the combustion chamber; Combustion gas injection nozzle for injecting combustion gas, a drive mechanism for rotating the rotary kiln type drying chamber along its axis, and an object supply device provided on the inlet side of the rotary kiln type drying chamber. It is characterized by being.

  A rotary kiln type drying apparatus according to a second aspect of the present invention is the drying apparatus according to the first aspect of the present invention, wherein the fuel supply nozzle and the combustion are provided on the inlet side of the cylindrical combustion chamber toward the tangential direction of the combustion chamber wall surface. A uniform flame is generated in the combustion chamber by the fuel and the combustion gas respectively injected from the gas injection nozzle.

  A rotary kiln type drying apparatus according to a third aspect is the drying apparatus according to the first aspect or the second aspect, wherein the nozzle provided in the cylindrical combustion chamber blows a mixed fluid of fuel and combustion air. It is a nozzle to be inserted.

  According to the drying apparatus of the present invention, a uniform tubular flame is generated in the cylindrical combustion chamber provided coaxially with the outside of the rotary kiln type drying chamber. The whole can be heated uniformly. As a result, the temperature inside the rotary kiln-type drying chamber is raised smoothly and uniformly, and the material to be dried charged in the drying chamber can be indirectly heated uniformly and dried extremely efficiently. Further, as before, it is not necessary to heat the inside of the cylindrical combustion chamber to a temperature sufficient to raise the temperature of the object to be dried before putting the object to be dried into the drying chamber. There is an advantage that a stable drying operation can be performed without causing thermal deformation of the inside of the chamber and the cylindrical combustion chamber due to an unnecessarily high temperature and causing mechanical deterioration.

  In the drying apparatus of the present invention, a nozzle for injecting fuel into the combustion chamber and a nozzle for injecting combustion gas into the cylindrical combustion chamber arranged coaxially with the drying chamber outside the rotary kiln type drying chamber are provided in the combustion chamber. It is provided in the tangential direction of the wall surface. Therefore, a uniform tubular flame is generated in the cylindrical combustion chamber by the fuel and the combustion gas blown from the nozzle into the cylindrical combustion chamber or a mixed fluid of the both, and the cylindrical combustion chamber is formed by this tubular flame. As a result of being heated uniformly throughout the cross section and the longitudinal direction, the object to be dried inserted into the rotary kiln type drying chamber can be efficiently dried.

  FIG. 1 is a schematic sectional view showing an embodiment of the rotary kiln type drying apparatus of the present invention. As shown in FIG. 1, a fixed cylindrical combustion chamber 2 having a diameter larger than the outer diameter of the drying chamber 1 and having a shorter length is provided outside the rotary kiln type drying chamber 1 formed of a horizontal rotary cylindrical furnace. 1 is provided in coaxial contact with the drying chamber 1 and in airtight contact with the drying chamber 1. On the inlet side of the rotary kiln-type drying chamber 1, a supply device 3 for drying objects is provided, and on the outlet side thereof, a discharge port 4 for dried materials is provided. The rotary kiln-type drying chamber 1 and the cylindrical combustion chamber 2 are formed with a downward slope from the inlet side toward the outlet side, that is, the discharge direction of the dried material. The drying chamber 1 is driven by a drive mechanism (not shown). It is the same as that of the conventional apparatus that it rotates slowly about its axis while sliding on the cylindrical combustion chamber 2.

  In the present invention, a fuel supply nozzle 8 is attached to the upper part of one end of the cylindrical combustion chamber 2, and a combustion gas blowing nozzle 9 such as combustion air or oxygen-containing gas is attached to the lower part thereof. The fuel supply nozzle 8 and the combustion gas injection nozzle 9 are provided toward the inner wall surface tangential direction of the cylindrical combustion chamber 2 as shown in FIG. It constitutes a burner. 6 is an exhaust pipe provided on the outlet side of the cylindrical combustion chamber 2.

  From the nozzles 8 and 9 constituting the tubular flame burner provided in the cylindrical combustion chamber 2, the fuel and the combustion air or the mixed fluid supplied into the combustion chamber 2 become a swirling flow and an axial center having a small swirling speed. The combustion exhaust gas having a light density is present on the side, and unburned gas and fuel are present on the inner wall side of the cylindrical combustion chamber 2 having a high swirl speed. Further, in the vicinity of the inner wall of the cylindrical combustion chamber 2, since the swirl speed exceeds the flame propagation speed, the flame cannot stop near the inner wall.

  As a result, a uniform tubular flame is generated in the cylindrical combustion chamber 2, and this tubular flame reduces the uneven temperature distribution in the cylindrical combustion chamber 2. It can be heated uniformly in the whole direction. Therefore, the temperature inside the rotary kiln-type drying chamber 1 is raised smoothly and uniformly, and the material 7 to be dried inserted into the drying chamber 1 can be uniformly and indirectly heated and dried extremely efficiently. In addition, when high temperature is not required as a drying apparatus, since the tubular flame burner of this invention can throw in excess air, low temperature combustion is also possible.

  In this regard, with conventional combustion burners (spray type oil burners, etc.), if the input of air is excessive, the flame will disappear. Therefore, it is necessary to provide a separate input port and input the air. There is a problem that control is difficult. Further, unlike the prior art, it is not necessary to heat the inside of the cylindrical combustion chamber 2 to a temperature sufficient for the temperature of the material to be dried 7 to rise before the material to be dried 7 is put into the drying chamber 1. Furthermore, the inside of the rotary kiln-type drying chamber 1 and the cylindrical combustion chamber 2 is not thermally deformed by an unnecessarily high temperature, and mechanical deterioration does not occur.

  The rotary kiln type drying apparatus of the present invention can be applied to drying, preheating, heating, and the like of coal and various other raw materials.

Schematic sectional view showing an embodiment of the rotary kiln type drying apparatus of the present invention Aa arrow view of FIG. Schematic sectional view showing an example of a conventional rotary kiln type drying apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary kiln type drying chamber 2 Cylindrical combustion chamber 3 To-be-dried material supply apparatus 4 Outlet 5 Burner 6 Exhaust pipe 7 To-be-dried material 8 Fuel supply nozzle 9 Combustion gas injection nozzle

Claims (3)

A rotary kiln-type drying chamber that is rotatable about its axis, and a cylindrical shape larger in diameter than the drying chamber, which is fixed to the outside of the rotary kiln-type drying chamber in coaxial and airtight contact with the drying chamber. A combustion chamber, a fuel supply nozzle for injecting fuel into the combustion chamber, and a combustion gas for injecting combustion gas, which are provided on the inlet side of the cylindrical combustion chamber toward the tangential direction of the wall surface of the combustion chamber A rotary kiln comprising a blowing nozzle, a drive mechanism for rotating the rotary kiln-type drying chamber along its axis, and an object supply device provided on the inlet side of the rotary kiln-type drying chamber. Type drying equipment.   The fuel and the combustion gas respectively injected from the fuel supply nozzle and the combustion gas blowing nozzle provided on the inlet side of the cylindrical combustion chamber toward the tangential direction of the wall surface of the combustion chamber enter the combustion chamber. The rotary kiln type drying apparatus according to claim 1, wherein a uniform tubular flame is generated.   3. The rotary kiln type drying apparatus according to claim 1, wherein the nozzle provided in the cylindrical combustion chamber is a nozzle for injecting a mixed fluid of fuel and combustion air. 4.

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