JP2022124545A - Device structure for preventing outflow of in-furnace gas and inflow of outside air into furnace in rotary cylindrical furnace - Google Patents

Abstract

To provide a method for driving a rotary cylindrical furnace capable of preventing the inflow of an out-furnace gas into a furnace and the outflow of an in-furnace gas to the outside of the furnace while smoothly supporting rotation, and a device structure thereof.SOLUTION: A rotary cylindrical furnace has a structure surrounded by a cylindrical cornice 21 connecting a rotary member (rotary flange) 100 equipped at the outside thereof with an end part stationary member (fixing flange) 110, and a stationary member (sliding flange) 22 contacted with the rotary flange and allowing rotation, wherein the inside of an internal space of the structure is filled with superheated steam with pressure higher than in-furnace pressure and outside air pressure.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device structure for preventing inflow of outside air into the furnace and outflow of gas inside the furnace in a rotary cylindrical furnace.

Rotating cylindrical furnaces are characterized by the efficient contact with gas during the rolling process of the solid particles thrown in, promoting the gas-solid reaction, good heat transfer efficiency, and easy operation. It is widely used in furnaces, combustion furnaces, firing furnaces, pyrolysis furnaces, etc.

The device structure is characterized by having a space (gap) at the inlet and the outlet of the rotary cylindrical furnace that allows rotation between the fixed part and outside air flowing into the furnace through this gap, or gas inside the furnace. Air leakage is inevitable. Therefore, in order for the furnace to function normally, it is necessary to prevent the inflow of outside air into the furnace and the outflow of the in-furnace gas to the outside air.

In particular, when used as a pyrolyzer,
・If outside air (oxygen) flows into the furnace filled with high-temperature combustible gas, an explosion will occur, leading to serious accidents such as damage to the furnace.
・Furnace gas contains toxic substances such as carbon monoxide, so the outflow of the gases will cause serious damage due to operation shutdown control.

Furthermore, a high-temperature apparatus such as a pyrolysis furnace swells in the direction perpendicular to the rotating shaft due to the thermal expansion of the furnace material, narrowing the gap between the rotating shaft and the cylindrical outer peripheral fixing member, thereby hindering rotation.
Therefore, it is important to design a method and a device structure for preventing the inflow of outside air gas from the gaps in front and behind the hollow thin plate cylinder (4) and the outflow of the harmful gas in the furnace to the outside environment while maintaining the rotation.

Methods (1) and (2) of sealing the gaps are available as methods for preventing the inflow of outside air and the outflow of furnace gas from the gaps in front and behind the rotary cylindrical furnace.
・Method (1)
Gland packing is attached to seal the cylindrical gap parallel to the rotation axis of the furnace.
・Method (2)
The cylindrical gap perpendicular to the axis of rotation of the furnace is sealed and the cylindrical gap parallel to the axis of rotation of the furnace is not sealed. Specifically, it is constructed such that gas is sealed in a gap between a rotary flange provided in the vertical direction to the furnace and a sliding flange surface in contact with the rotary flange.

Japanese Patent Application Laid-Open No. 2003-130550

However, although method (1) described above can deal with expansion and contraction in the direction of the rotation axis (x-axis) of the cylinder, there is a limit to dealing with swelling in the vertical (y-axis) direction. For example, when the temperature in the SUS furnace is 1000 degrees and the inner diameter of the furnace is 500 mmφ, the bulge is 10 mm. When this gap is sealed with a gland packing provided around the furnace, the compressed gland packing inhibits rotation.

Method (2) can deal with expansion and contraction in the direction of the rotation axis (x-axis) of the cylindrical furnace and expansion in the direction of the vertical (y-axis), but there is a limit to dealing with the pressure difference between the gas inside and outside the furnace. be. Specifically, when the furnace gas pressure exceeds 0.2 kPa, the gas flows out from the sliding surface to the outside air, and conversely, when it exceeds -2 kPa, the outside air flows into the furnace.

Therefore, the present invention provides a new space structure around a rotary cylindrical furnace that smoothly supports rotation and prevents the inflow of outside air into the furnace and the outflow of harmful furnace gases even in a high-temperature furnace with large thermal expansion. The purpose is to enable safe operation of the furnace by

In order to achieve the above object, the space structure of the present invention is a hollow cylindrical space surrounded by a rotary furnace, a bellows cylinder covering it, and a fixed part, and the space is controlled by the gas pressure in the furnace and the external pressure. The structure is filled with a third gas (a harmless gas that does not contain oxygen) that is higher than either and neither of them. Specifically, the space is provided between a sufficient gap that allows rotation between the rotating part and the fixed part, a rotary flange provided on the outer periphery of the rotary furnace and orthogonal to the rotation axis direction of the rotary furnace, and the fixed member. It has a gap between it and a sliding flange attached via a corrugated tube, and the space is filled with an inert gas.

As described above, the spatial structure of the rotary cylindrical furnace of the present invention includes a sufficient space between the rotating part and the fixed part to allow rotation, and a seal surface provided on the outer periphery of the rotary furnace and perpendicular to the axial direction of the rotary furnace. and a sliding flange attached to a fixed member via a bellows tube, the sliding flange abutting against the rotating flange, and the bellows tube, the rotary cylindrical furnace, and the fixed part A gas which is a harmless gas different from the furnace gas and outside air and whose pressure is higher than the pressure inside the furnace is fed into the space composed of . With such a structure, expansion in the x-axis direction is caused by the expansion and contraction of the bellows tube, and expansion in the y-axis direction is caused by the gap between the rotating surface and the sliding surface. Since the gas flows into the furnace or flows out of the furnace, as a result, it is possible to prevent outside air from flowing into the furnace and furnace gas from flowing out of the furnace.

It is a sectional view explaining the whole composition of a rotary cylindrical furnace. FIG. 3 is a cross-sectional view of a main part of the fixed part connection structure (inlet) of the rotary cylindrical furnace; It is an explanatory view explaining the structure of a pedestal. Fig. 3 is a cross-sectional view of a main part of the fixed part connection structure (outlet) of the rotary cylindrical furnace;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the constituent elements described in the following examples are examples, and are not intended to limit the technical scope of the present invention only to them.

(Constitution)
First, the overall configuration of the rotary cylindrical furnace of the present invention will be described with reference to FIG. In the present invention, the term "rotary cylindrical furnace" is defined as including both rotation about a horizontal axis and rotation about an inclined axis (rotary kiln). As shown in FIG. 1, the rotary cylindrical furnace 1 includes fixed members on the inlet side: a screw feeder casing 11, a fixed member housing 12 on the outlet side, a rotary furnace 10, a rotary support device 13, and the like. The rotary furnace 10 is formed in a cylindrical shape made of metal, and is rotationally driven by rollers 13 while the vicinity of both ends thereof is inserted into a casing 11 and a housing 12 . The inside of the rotary furnace is equipped with a packed layer of solid particles, and the gas always passes through the layer of solid particles. Inflow of outside air into the furnace and outflow of furnace gas into the outside air cannot be prevented. It should be noted that the internal structure of the rotary furnace 10 does not have to be the illustrated structure, and may be of any type.

The raw material introduced from the screw feeder housing 11 side rolls with the rotation of the rotary furnace 10 and undergoes a gas-solid contact reaction while being transported toward the outlet, and is discharged from the housing 12 on the outlet side. The rotary cylindrical furnace 1 of Example 1 is surrounded by a rotary flange 100 that rotates integrally with the rotary furnace 10, fixed flanges 110 (120) as fixed members arranged on both left and right sides, and a bellows cylinder. The space is filled with superheated steam.

FIG. 2 shows the structure of the inlet of the rotary cylindrical furnace of this embodiment, and FIG. 3 shows the structure of the outlet. A rotary flange 100 provided on the outer periphery of the rotary furnace 10 and installed in the direction of the rotation axis and the vertical direction of the rotary furnace 10, a fixed flange 110 (120) as a fixed member, and a bellows circular tube 21. and a sliding flange 22 .

The rotary flanges 100 are annular (flange-shaped or circular-shaped with a circular opening in the vicinity of the center) thin plate members that are provided in the vicinity of both ends of the rotary furnace 10 in the vertical direction to the rotary shaft of the rotary furnace 10. be.

The fixed flange 110 (120) as the fixed member of this embodiment further has an air supply hole 24 communicating with the space surrounded by the rotary flange 100, the sliding flange 22, the bellows tube 21 and the fixed member. As will be described later, a harmless gas containing no oxygen is fed into this space through the air feeding hole 24 from an air feeding device (not shown).

A sliding flange 22 is attached to the fixed flange 110 (120) through a bellows tube 21. As shown in FIG. The bellows tube 21 is made of stainless steel and formed into a cylindrical bellows shape (bellows shape, accordion shape) as a whole, and is formed to be elastically deformable. The corrugated tube 21 is installed between the fixed flange 110 and the rotating flange 100 so as to surround the cylindrical furnace. It is adapted to be urged by an elastic force.

That is, the rotary flange 100 is formed by expanding the diameter of both end surfaces of the cylindrical rotary furnace 10 radially outward. Then, a harmless gas containing no oxygen flows into the furnace and outflows to the atmosphere through the axially outward surface of the rotating flange 100, thereby preventing the outflow of the gas in the furnace and the inflow of the atmosphere.

The sliding flange 22 is an annular thin plate member perpendicular to the axial direction of the rotary furnace 10 (a collar-like shape or a circular shape having a circular opening near the center). Since the sliding flange 22 is only fixed to the corrugated tube 21 at its rear side, it can move in the axial direction of the rotary furnace 10 as the corrugated tube 21 expands and contracts. Furthermore, graphite 23 having the same shape as the sliding flange 22 is installed on the front side of the sliding flange 22 (the side that contacts the rotary flange 100). The graphite 23 has the function of reducing the frictional resistance of the contact surface (seal surface) with the rotating flange 100 and preventing the wear of the sliding flange 22 by wearing itself.

As described above, the fixed flange 110, the inner cylinder 111 (the outer surface thereof), the rotary flange 100, the sliding flange 22, the bellows tube 21 (the inner surface thereof), and the fixed member form a space. partitioned. Then, harmless gas containing no oxygen is inserted into this space through the air supply hole 24 on the upstream side. Furthermore, the downstream side of the space is connected to the gap between the inner cylinder 111 extending from the housing 11 on the inlet side and the rotary furnace 10 .

Here, the gas supplied through the air supply holes 24 will be described. First, the pressure of the gas is adjusted so that it is higher than the pressure inside the rotary furnace 10 and part of the introduced gas flows out from between the rotating flange 100 and the sliding flange 22 .

That is, the pressure of gas inserted into the space is set according to the following criteria.
(1) higher than the pressure in the rotary furnace 10;
First, in order to prevent the gas inside the rotary furnace 10 from leaking to the outside, the pressure inside the space must be higher than the pressure inside the rotary furnace 10 .
(2) A little leakage from the gap between the rotating flange 100 and the sliding flange 22;
In other words, the elastic force of the bellows tube 21 is adjusted to the extent that it slightly leaks from the gap between the rotating flange 100 and the sliding flange 22 .

The gas to be inserted is preferably the third pressurized harmless inert gas that does not contain oxygen, instead of the gas inside the furnace or the outside gas. Furthermore, the gas is preferably the gas that is used in the reaction within the rotary furnace 10 . For example, if the rotary furnace is a pyrolysis furnace and a high concentration of hydrogen is to be obtained from biomass, the gas to be fed is preferably superheated steam (SHS).

(effect)
Next, the effects of the closed spaces around the inlet and outlet of the rotary cylindrical furnace of the embodiment will be enumerated and explained.

(1) As described above, the structure around the inlet and outlet of the rotary cylindrical kiln of the embodiment is the rotary kiln seal structure 2 disposed between the rotary kiln 10 of the rotary kiln 1 and the fixed flange 110 as a fixed member. A rotary flange 100 provided on the outer periphery of the rotary furnace 10 and having a sealing surface orthogonal to the axial direction of the rotary furnace 10, and a sliding member attached to a fixed flange 110 as a fixed member via a bellows tube 21. and a sliding flange 22 abutting the rotating flange 100 . With such a configuration, the inflow and outflow of gas in the furnace can be prevented even if a pressure difference occurs between the pressure inside the furnace and the pressure outside while supporting the rotation smoothly. Furthermore, it is possible to follow the elongation of the rotary furnace 10 by expanding and contracting using a simple mechanism.

(2) The bellows tube 21 is formed to be elastically deformable, and is installed between the fixed flange 110 and the rotating flange 100 as a fixing member so as to cover the rotary furnace 10 . Since the rotary furnace 10 is biased toward the axial direction, it can follow the expansion and contraction of the rotary furnace 10 in the axial direction. Furthermore, by pressing the sliding flange 22 toward the rotating flange 100 with an elastic force, leakage from the sliding surface can be suppressed while allowing rotation.

(3) Furthermore, the fixed flange 110 as a fixed member further has an air supply hole 24 leading to the space surrounded by the rotating flange 100, the sliding flange 22 and the bellows tube 21, and through the air supply hole 24, gas is supplied to the inside of the space. are sent in. With such a configuration, the inflow of outside air into the rotary furnace 10 can be prevented.

(4) In addition, since the pressure of the supplied gas is adjusted to be higher than the pressure inside the rotary furnace 10 and the pressure of the outside air, there is neither an outflow of gas inside the furnace nor an inflow of outside air into the furnace.

(5) For example, the rotary cylindrical furnace 1 is a pyrolysis furnace, and when synthesis gas or hydrogen is produced by thermal decomposition of biomass, if superheated steam is selected as the gas to be fed, tar, char It is convenient because steam can be used for the reforming reaction of

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes to the extent that they do not depart from the gist of the present invention can be applied to the present invention. included.

Reference Signs List 1: rotary kiln 10: rotary furnace 100: rotary flanges 11, 12: housing 110: fixed flange 111: inner cylinder 13: rotary support device 2: rotary kiln seal structure 21: bellows tube 22: sliding flange 23: graphite 24: feed Pore 3: Pedestal 31: Bearing

Claims (4)

At the connecting portion between the rotating member and the fixed member of the rotary cylindrical furnace,
a space surrounded by the rotating member, the fixed member, the rotating cylindrical furnace, and the hollow thin-plate cylinder outside the rotating cylindrical furnace,
A device structure that enhances the safety and performance of rotary cylindrical furnace operation by filling with an inert gas at a pressure higher than both the furnace external pressure and the furnace internal pressure. 2. The device structure according to claim 1, wherein said hollow thin-plate cylinder is a corrugated tube. 3. The apparatus according to claim 1 or 2, wherein the end portion of the rotating member and the annular flange provided at the end portion of the hollow thin plate cylinder are in contact with each other so as to allow rotation of the furnace. structure. 4. The apparatus structure according to any one of claims 1 to 3, wherein said inert gas is superheated steam.

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