JP2007139289A - Continuous kiln - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To treat gas collected in a temperature region less than a catalyst activation temperature inside a furnace in a continuous kiln used in a burning process in manufacturing a plasma display panel. <P>SOLUTION: The continuous kiln in which a work piece is heated according to a predetermined temperature profile while being transported in the furnace is equipped with a discharge box 31 for collecting binder-removed gas generated from the work piece, a catalyst unit 41 for performing decomposition treatment of the collected binder-removed gas in the furnace, and a discharge pipe 33 extending in the furnace from the discharge box 31 toward the catalyst unit 41. The catalyst unit 41 is further on the downstream side than the discharge box 31 in the transporting direction, and is provided in a furnace region in which the temperature is the temperature for decomposition by the catalyst of the binder-removed gas generated from the work piece is activated or higher. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, a continuous firing furnace used in a firing process for manufacturing a plasma display panel, and also relates to a continuous firing furnace used in a processing process in which a binder removal gas is generated.

The binder removal gas refers to an organic component or an organic substance generated from a workpiece in a firing process, or a gas generated by combustion or decomposition thereof.

  Conventionally, as this type of continuous firing furnace, an exhaust box capable of sucking the debinding gas is provided in a temperature range below the activation temperature of the catalyst for treating the debinding gas in the furnace. The exhaust pipe is led from the box to the outside of the furnace. The exhaust pipe outside the furnace is equipped with a catalyst unit with a built-in heater that heats the binder removal gas to a temperature at which it can be decomposed by the catalyst (hereinafter referred to as catalyst activation temperature). Is known (see, for example, Patent Document 1).

In the conventional continuous firing furnace, a large amount of electric power is consumed to heat the binder removal gas by the heater. Furthermore, since the catalyst unit is outside the furnace, the ambient temperature outside the furnace is increased by heat radiation from the surface of the catalyst unit. In addition, with the recent material reforms, the debinding gas has become increasingly polymerized, and it has become difficult to decompose with a catalyst unless the debinding gas is heated to a higher temperature, making it more difficult to decompose the debinding gas. It is coming.
JP 2004-316987 A

  An object of the present invention is to provide a continuous firing furnace capable of treating the debinder gas collected in a temperature region below the activation temperature of the catalyst in the furnace.

  A continuous firing furnace according to the present invention is a continuous firing furnace in which a work is heated according to a predetermined temperature profile while being conveyed in the furnace, and an exhaust box for collecting a debinding gas generated from the work, and the collected A catalyst unit that decomposes the debinding gas in the furnace and an exhaust pipe that extends from the exhaust box toward the catalyst unit are provided in the furnace, and the catalyst unit is downstream of the exhaust box in the transport direction. The debinder gas generated from the workpiece is provided in the furnace region where the temperature is higher than the temperature at which decomposition by the catalyst is activated.

  In the continuous firing furnace according to the present invention, the binder removal gas released from the work before being diffused and contaminated in the furnace can be effectively collected, and the atmosphere in the furnace can be kept clean. Also, the collected debinding gas is led to the downstream side in the transport direction through the exhaust pipe by the exhaust pipe and reaches the catalyst unit installed in the in-furnace region that is at or above the catalyst activation temperature. Energy is saved without the need for a heater.

  Furthermore, if the catalyst unit is installed on the higher temperature side than the region where the debinding gas is generated from the workpiece, not only the debinding gas that is difficult to decompose at a lower temperature can be reliably decomposed, but it can also prevent clogging in the exhaust pipe. be able to.

  Also, if the outlet end of the exhaust pipe is led out of the furnace and the inlet of the ejector is connected to the outlet end of the exhaust pipe, the ejector is forced to exhaust while controlling the debinding gas after processing. Can do.

  In addition, if there are a plurality of exhaust boxes and each exhaust box is located at a different temperature, the debinder gas can be efficiently collected near the source, and the furnace atmosphere is contaminated. Can be minimized.

  In addition, if the exhaust pipe is provided with branch pipes that are branched so as to correspond to all the exhaust boxes, a plurality of exhaust boxes can share one catalyst unit, saving space in the furnace and equipment costs. This leads to reduction and easy maintenance.

  According to this invention, the binder removal gas collected in the temperature region below the activation temperature of the catalyst can be treated in the furnace, and power saving can be achieved.

  Embodiments of the present invention will be described below with reference to the drawings.

  The continuous firing furnace includes a furnace body 11. The furnace body 11 has a rectangular cross section and includes a pair of side walls 21, a top wall 22, and a bottom wall 23. Both side walls 21, top wall 22, and bottom wall 23 are made of ceramic fiber heat insulating material. The top wall 22 and the bottom wall 23 are provided with heaters (not shown). A plurality of horizontal transport rollers (not shown) are installed in the furnace at regular intervals in the furnace length direction. The substrate to be fired (work) is placed on a setter and conveyed in the furnace length direction by a conveying roller.

  The left side in FIG. 1 is the furnace inlet side, and the right side is the furnace outlet side. A preheating region, a main heating region, and a slow cooling region are sequentially formed from the inlet to the outlet in the furnace. While the substrate is passed through the preheated region, debinding gas is generated from the substrate. The temperature of the preheating region gradually increases as it proceeds downstream in the substrate transport direction. The temperature at which the debinding gas is generated varies depending on the components of the binder, but is, for example, 100 to 400 ° C. For example, most of the debinding gas is generated in the temperature range of 300 ° C.

  An exhaust box 31 is provided in the furnace. The exhaust box 31 is in the shape of a horizontal rectangular parallelepiped box that is disposed at least in a temperature region where the most binder removal gas is generated and extends above the height in the furnace in the furnace width direction. A large number of exhaust suction holes 32 are scattered on the bottom wall of the exhaust box 31.

  Two horizontal exhaust pipes 33 extend in parallel with each other toward the downstream side in the transport direction from two places in the length direction of the exhaust box 31. At the downstream end of the exhaust pipe 33 in the transport direction, the exhaust pipe 33 is bent in an L shape toward the side wall 21 on the near side and penetrated through the side wall 21. The outlet end of the exhaust pipe 33 is directed upward. An outlet of the vertically upward ejector 34 is connected to an outlet end of the exhaust pipe 33.

A catalyst unit 41 is connected to the exhaust pipe 33. The catalyst unit 41 is a unit in which a carrier (not shown) carrying a catalyst is accommodated in a casing 42. As the catalyst, Pt, Pd, Ag ₂ O or the like having an activation temperature (depending on the type of the debinding gas) of 200 to 500 ° C. is preferable. The carrier is made of a ceramic, a refractory metal honeycomb structure, or a pellet structure. A filter may be disposed on the upstream side of the carrier in the casing 42.

  The catalyst unit 41 is disposed in a temperature region that activates the catalyst, but is upstream of the main heating region in the substrate transport direction. For example, when the ultimate temperature in the preheating region is 300 ° C. and the ultimate temperature in the main heating region is 600 ° C., the catalyst unit 41 is preferably arranged in a temperature region of 400 to 500 ° C., for example.

  The inside of the furnace is heated by a heater, and a temperature region corresponding to the outside air to the main heating region is formed. The entire catalyst unit 41 including the casing 42 is heated to a temperature close to the temperature in the furnace. The generated debinding gas is sucked into the exhaust box 31 through the exhaust suction hole 32. The exhaust box 31 is exhausted to the outside of the furnace through the exhaust pipe 33. On the way, the debinding gas is brought into contact with the catalyst and is oxidatively decomposed (combusted). At this time, the temperature of the catalyst is about 450 to 500 ° C. The treated debinding gas is forcibly exhausted by the ejector 34 from the outlet end of the exhaust pipe 33.

  FIG. 4 shows an example in which a plurality of exhaust boxes 31 are arranged in the furnace. In this example, the number of exhaust boxes 31 is two. The exhaust pipe 33 is branched at a portion immediately downstream of the exhaust box 31 on the downstream side in the substrate transport direction, bypasses the exhaust box 31 on the downstream side, and has a branch pipe 51 extending to the exhaust box 31 on the upstream side. is doing.

It is a vertical longitudinal cross-sectional view of the continuous baking furnace by this invention. It is a horizontal longitudinal cross-sectional view of the continuous firing furnace. It is a vertical cross-sectional view of the continuous firing furnace. It is sectional drawing equivalent to FIG. 2 which shows the modification of the exhaust box of the same continuous baking furnace.

Explanation of symbols

11 Furnace
31 Exhaust box
33 Exhaust pipe
34 Ejector
41 Catalyst unit

Claims (5)

  In a continuous firing furnace where the workpiece is heated according to a predetermined temperature profile while it is transported in the furnace, an exhaust box that collects the debinding gas generated from the work and the collected debinding gas are decomposed in the furnace. A catalyst unit to be treated and an exhaust pipe extending from the exhaust box toward the catalyst unit in the furnace, the catalyst unit being downstream of the exhaust box in the transport direction and debinding gas generated from the workpiece A continuous firing furnace characterized by being provided in a region in the furnace at a temperature equal to or higher than a temperature at which decomposition by the catalyst is activated.   The continuous firing furnace according to claim 1, wherein the catalyst unit is provided on a higher temperature side than a region where the binder removal gas is generated from the workpiece.   The continuous firing furnace according to claim 1 or 2, wherein an outlet end of the exhaust pipe is led out of the furnace, and an outlet of the ejector is connected to the outlet end of the exhaust pipe.   The continuous firing furnace according to claim 1 or 2, wherein the number of exhaust boxes is plural, and each exhaust box is positioned at a different temperature. The continuous firing furnace according to claim 4, wherein the exhaust pipe includes a branch pipe branched to correspond to all the exhaust boxes.

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