JP2006038307A - Pyrolysis plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select a material capable of reducing wear of a material used in a seal in regard to a gas seal utilizing metallic contact for preventing leakage to the atmosphere of pyrolysis gas or heated air of a rotary kiln type pyrolysis plant. <P>SOLUTION: In the gas seal utilizing metallic contact of a fixed ring and a rotating ring, by providing a composition combined such that one of materials used in the fixed ring or the rotating ring is a material of high hardness, wear due to the metallic contact of the fixed ring and the rotating ring can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotary kiln type gasification melting furnace, and more particularly to a thermal decomposition apparatus.

  In the pyrolysis device of a rotary kiln type gasification melting furnace, in order to prevent the pyrolysis gas generated in the kiln and the heated air for heating the kiln from leaking out of the pyrolysis device, a gas seal is provided. Have.

  In the conventional gas seal, a seal ring is provided on the movable side along the outer periphery of the rotating kiln, and a fixed seal ring is disposed at a position opposite to the movable seal ring. In this configuration, the movable side seal ring is pressed with a constant pressure. In order to secure the sealing performance of the gas seal, an extendable and contractible bag body that can supply fluid pressure was used as means for pressing the fixed seal ring against the movable seal ring at a constant pressure. As a result, the sealing performance between the movable part and the fixed part of the rotating kiln is improved and gas leakage from the rotating kiln is eliminated, so that the operation of the rotating kiln can be stabilized. However, in the conventional gas seal, since it is difficult to reduce the wear of the seal ring, it has not been a gas seal that can maintain reliability over a long period of time.

JP 2003-269864 A

  However, in the conventional gas seal, since it is difficult to reduce the wear of the seal ring, it has not been a gas seal that can maintain reliability over a long period of time.

  An object of the present invention is to provide a thermal decomposition apparatus capable of reducing wear of a sliding portion of a seal device.

  A feature of the present invention that achieves the above-described object is that a sealing device is installed in a rotary kiln and rotates with the rotary kiln, and the first ring member is pressed against the first ring member to contact the first ring member. There is a second ring member to be installed, and one of the first ring member and the second ring member is made of a material having higher hardness than the other ring member. Thereby, the abrasion by the contact of a 1st ring member and a 2nd ring member can be reduced.

  The above-described object can also be achieved by configuring the first ring member and the second ring member of the sealing device with chrome molybdenum steel. Thereby, the abrasion by the contact of a 1st ring member and a 2nd ring member can be reduced.

  The above-mentioned object can also be achieved by coating each surface of the first ring member and the second ring member of the sealing device with chrome molybdenum steel. Thereby, wear due to contact between the first ring member and the second ring member can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the abrasion of the sliding part of the sealing device in a rotary kiln-type thermal decomposition apparatus can be reduced. The life of the sealing device can be extended and the operating rate of the pyrolysis device can be improved.

  Hereinafter, a thermal decomposition apparatus which is a preferred embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  Gasification melting type waste incineration involves separating the waste into pyrolysis gas and pyrolysis carbon (hereinafter referred to as char), and then charging char and ash into a melting furnace heated to high temperature by pyrolysis gas. The ash is made into molten slag. By this method, waste can be treated at a high temperature, so that the generation of dioxins can be suppressed, and the final product slag can be effectively used for building materials and the like, so the amount of landfill at the final disposal site can be greatly reduced. Furthermore, since these treatments are covered with the energy of the waste, the external energy required for the waste treatment can be greatly reduced.

  FIG. 1 is a schematic diagram showing the configuration of a thermal decomposition apparatus 30 according to this embodiment of a rotary kiln type gasification melting furnace. Garbage 1 brought into the incineration site passes through a pretreatment process, is then put into a thermal decomposition apparatus, and is sent into the kiln by the screw feeder 2 from the entrance of the horizontal kiln 3. Garbage in the kiln is decomposed into pyrolysis gas 4 and char 5 by being heated in an atmosphere in which air is blocked while moving toward the outlet, and is sent to the respective treatment systems. In this process, since aluminum, iron, etc. are processed below the melting point, they are recovered as incombustible material 6 as it is. On the other hand, the heated air 7 for heating the dust heats the kiln by circulating in the forward or reverse direction with respect to the moving direction of the waste through the path constituted by the kiln and the jacket 8. The garbage in the kiln is supplied with heat from the heated kiln. At this time, the kiln is rotated to uniformly and efficiently supply heat to the garbage.

  Pyrolysis gas generated from garbage put into the kiln contains combustion gases such as carbon monoxide, hydrogen, hydrocarbons, etc., but because they are toxic and odorous, such as carbon monoxide, leak into the atmosphere It is not possible. Further, the heated air obtained by heating the pyrolysis gas with the pyrolysis gas burner also contains a toxic gas and cannot be leaked to the atmosphere. Therefore, in the fixed part of the pyrolysis device that is the path of pyrolysis gas and heated air and the rotary kiln that generates pyrolysis gas, a seal structure for preventing these gases from leaking into the atmosphere Is required. These gas seals are necessary for the contact surface 9 between the rotating kiln and the jacket which is a fixed portion, and the contact surface 11 between the rotating kiln and the garbage input hood 10. These gas seals may basically have the same structure. Therefore, a gas seal used in the thermal decomposition apparatus 30 will be described below by taking as an example a gas seal on a contact surface between a rotating kiln and a jacket that is a fixed portion.

  FIG. 2 shows an example of the structure of the gas seal at the position described above. A collar 12 is attached to an outer peripheral portion near the end of the rotating kiln 3, and a rotating ring 13 is fixed by bolts 14 and nuts 15 so as to be sandwiched between the collars. Therefore, the rotating ring rotates at the same speed as the kiln rotates. The kiln material and the rotating ring material need not be the same. On the other hand, a stationary ring 17 is attached to a stationary jacket 8 by a bellows 16. Therefore, heated air does not leak from the gap between the jacket and the fixing ring.

  The gas seal is maintained by metal contact between the rotating ring and the stationary ring, but the above-mentioned difference in thermal expansion is not applied to the bellows so that no gap is generated between the rotating ring and the stationary ring due to the difference in thermal expansion between the kiln and the jacket. Is absorbed by. Further, in order to ensure the sealing performance between the rotating ring and the fixing ring, the fixing ring is pressed against the rotating ring with a constant pressure by the spring bolt 18. The fixing ring is provided with a groove 19 for storing a lubricant. When the rotating ring rotates, the lubricant is supplied to the contact surface between the rotating ring and the fixing ring. The groove for storing the lubricant may be provided in the rotating ring, or may be provided in both the rotating ring and the fixed ring.

  Wear is a phenomenon in which various factors affect each other in a complicated manner, and thus quantitative prediction and evaluation are extremely difficult. Among them, Holm's law is known to explain wear characteristics by a relatively simple equation. That is, the wear amount W is determined by the combination of materials with the true contact area (not the apparent contact area, the area where the materials are actually in contact) Ar, the wear distance L, and the probability that the atoms will be stripped off by the contact. Associated with the value z.

W = Z · Ar · L (1)
In addition, since the true contact area Ar is very small compared to the apparent contact area, the pressure at the true contact surface is very high, and the plastic flow pressure Pm exceeds the elastic limit. Therefore, the load P applied to the wear surface and the true contact area are:
P = Ar · Pm (2)
Can be described. Rewriting equation (1) using equation (2)
W = (z · P · L) / Pm (3)
It becomes. That is, it is understood that the wear amount W is proportional to the load and the wear distance, but inversely proportional to the plastic flow pressure Pm. This indicates that the amount of wear decreases as the plastic flow pressure increases, indicating that the material whose hard contact area is less likely to increase due to load, that is, the harder the material, the harder the wear. Further, according to this equation, when a hard material and a soft material are combined, the soft material wears unilaterally.

  However, although this description can be applied in the case of dry wear with no lubricant, it is not such a simple relationship with lubricant. When there is a lubricant, the deformation of the material contact portion (true contact portion) is relaxed by the lubricant (relaxation of direct contact by high pressure), and the amount of wear is reduced. In particular, in the case of a soft material that is easily deformed, the effect of the lubricant is strongly received. Thus, according to Holm's equation, softer materials are expected to accelerate wear, but this is not necessarily the case with lubricant. Further, if one is made of a hard material, the wear powder generated therefrom can be reduced, so that the wear of the other soft material is also reduced.

  Therefore, the gas seal of the thermal decomposition apparatus 30 is characterized in that the gas seal is performed by metal contact between materials obtained by combining one of the material of the rotating ring and the material of the fixed ring so as to be a material having high hardness. is there.

  FIG. 3 is a schematic diagram showing the configuration of a thermal decomposition apparatus which is another embodiment of the rotary kiln system according to the present invention. In FIG. 3, the kiln and the outer jacket rotate. The gas seal used in the thermal decomposition apparatus 30A of the present embodiment includes a contact surface 21 between the rotating jacket and the heated air hood 20 as a fixed portion, and a contact surface 22 between the rotating kiln and the heating hood.

  The gas seal of the pyrolyzer 30A is obtained by using the metal contact surface of the rotating ring or the metal contact surface of the fixed ring, or both the metal contact surface of the rotating ring and the metal contact surface of the fixed ring. Gas sealing is performed by metal contact between the coated materials so that the contact portion has high hardness.

  A wear test apparatus used for selecting a material to be applied to the gas seal of the thermal decomposition apparatus will be described with reference to FIG. This wear test apparatus is a schematic diagram of a wear test apparatus for carbon steel, austenitic stainless steel, and chromium molybdenum steel. The wear test apparatus has a rotating part 23 and a fixing part 24. By storing the lubricant in a groove 25 cut in the fixing part, the lubricant is applied to the contact surface between the rotating part and the fixing part together with the rotation of the rotating part. Is supplied. In the wear test, two cases of a case where the fixed part was made of carbon steel and the rotating part was made of austenitic stainless steel and a case of chromium molybdenum steel harder than austenitic stainless steel were carried out. The result is shown in FIG.

When the rotating part is austenitic stainless steel with respect to the fixed part of carbon steel, the specific wear amount of carbon steel is about 10 ^-8 (mm ³ / N / mm), and the austenitic stainless steel is about 2 ×. 10 ⁻⁹ (mm ³ / N / mm). On the other hand, when the rotating part is made of chromium molybdenum steel harder than austenitic stainless steel with respect to the fixed part of carbon steel, the specific wear amount is about 10 ⁻¹⁰ (mm ³ / N for both carbon steel and chromium molybdenum steel). / Mm), and the specific wear amount of the fixed part material and the rotating part material was reduced.

  From the above, the gas seal, which is another embodiment of the pyrolysis apparatus, is made of metal contact between chrome molybdenum steel and other metal, metal contact between chrome molybdenum steel coated material and other metal, and chrome molybdenum steel coated. It is characterized by gas sealing by metal contact between the prepared material and a material coated with another metal.

  Further, from FIG. 5, it can be considered that the combination of chromium molybdenum steels can most reduce the wear of the rotating ring and the fixing ring, so that Claim 4 of the present invention is the thermal decomposition apparatus according to Claims 1 and 2, Gas sealing is performed by metal contact between chromium molybdenum steels or metal contact between materials whose metal surfaces are chromium molybdenum steel.

It is a block diagram of the thermal decomposition apparatus which is one preferable Example of this invention. It is a block diagram of the gas seal of the thermal decomposition apparatus shown in FIG. It is a block diagram of the thermal decomposition apparatus which is the other Example of this invention. It is a schematic diagram of the abrasion test apparatus used in order to select the material applied to the gas seal of the thermal decomposition apparatus which is an Example of this invention. It is a figure which shows the result of the abrasion test implemented in order to select the material applied to the gas seal of the thermal decomposition apparatus which is this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Garbage, 2 ... Screw feeder, 3 ... Kiln, 4 ... Pyrolysis gas, 5 ... Char, 6 ... Incombustible material, 7 ... Heated air, 8 ... Jacket, 9 ... The rotating kiln and the jacket which is a fixed part Contact surface, 10 ... Garbage hood, 11 ... Contact surface between rotating kiln and garbage hood as fixed part, 12 ... Brim, 13 ... Rotating ring, 14 ... Bolt, 15 ... Nut, 16 ... Bellow, 17 ... Fixing ring, 18 ... spring bolt, 19 ... groove for storing lubricant, 20 ... heated air hood, 21 ... contact surface of rotating jacket and heating air hood as fixing portion, 22 ... rotating kiln and fixing portion Contact surface with the heated air hood, 23... Rotating part of the wear test device, 24... Fixed portion of the wear test device, 25... Groove for storing the lubricant cut in the fixed portion.

Claims (8)

A rotary kiln to which waste to be thermally decomposed is supplied, a jacket member that surrounds the outer side of the rotary kiln and is supplied with a heat medium for heating the rotary kiln, and a seal provided between the rotary kiln and the jacket member With the device,
The seal device is installed in the rotary kiln and rotates with the rotary kiln, and a second ring that is pressed against the first ring member to contact the first ring member and installed in the jacket member A thermal decomposition apparatus comprising: a member, wherein one of the first ring member and the second ring member is made of a material having a hardness higher than that of the other ring member.   2. The thermal decomposition apparatus according to claim 1, wherein when the metal is coated on both the surface of the metal contact portion of the first ring member and the surface of the metal contact portion of the second ring member, the one metal is replaced with the other metal. A thermal decomposition apparatus characterized by having a higher hardness.   2. The pyrolysis apparatus according to claim 1, wherein when one of the metal contact portion surface of the first ring member and the metal contact portion surface of the second ring member is coated with a metal, the hardness of the metal to be coated is the coating The thermal decomposition apparatus is characterized by being higher in hardness than the metal contact portion that is not subjected to any of   The thermal decomposition apparatus according to claim 1, wherein the one ring having high hardness is made of chromium molybdenum steel.   The thermal decomposition apparatus according to claim 2, wherein the one metal having high hardness is chromium molybdenum steel.   4. The thermal decomposition apparatus according to claim 3, wherein the coated metal is chromium molybdenum steel. A rotary kiln to which waste to be thermally decomposed is supplied, a jacket member that surrounds the outer side of the rotary kiln and is supplied with a heat medium for heating the rotary kiln, and a seal provided between the rotary kiln and the jacket member With the device,
The seal device is installed in the rotary kiln and rotates with the rotary kiln, and a second ring that is pressed against the first ring member to contact the first ring member and installed in the jacket member There is a member, and the first ring member and the second ring member are made of chromium molybdenum steel. A rotary kiln to which waste to be thermally decomposed is supplied, a jacket member that surrounds the outer side of the rotary kiln and is supplied with a heat medium for heating the rotary kiln, and a seal provided between the rotary kiln and the jacket member With the device,
The seal device is installed in the rotary kiln and rotates with the rotary kiln, and a second ring that is pressed against the first ring member to contact the first ring member and installed in the jacket member A pyrolysis apparatus comprising a member, and chromium molybdenum steel is coated on each surface of the first ring member and the second ring member.

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