JP2006317131A - Bottom section structure of waste melting furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bottom section structure of a waste melting furnace capable of preventing scattering of furnace dry distillation residue caused by increase of a furnace superficial velocity, and properly discharging molten matters while preventing formation of a core. <P>SOLUTION: In this bottom section structure of the waste melting furnace where the bottom section 3 is formed continuously from an inclined bosh portion 2 positioned at a lower portion of a shaft portion 1, a lower tuyere 4 and a discharge hole 5 for discharging the molten matter are formed on the bottom section 3, blocked carbon combustible substances such as waste and cokes are charged from a furnace upper portion, an oxygen source is supplied from a furnace lower portion, ash contents in the waste and non-burnt matters melted by reaction heat are discharged from the discharge hole of the bottom section, and a gas generated from the furnace upper portion is discharged, D1>D2>D3, and S1>S2>S3 are satisfied when a shaft diameter is D1, a diameter of an upper bottom section 3a is D2, a diameter of a lower bottom section 3b is D3, and their cross-sectional areas are respectively S1, S2 and S3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a furnace bottom structure of a waste melting furnace.

  A waste melting furnace is used for melting waste such as general waste and shredder dust (see Patent Document 1).

FIG. 3 is a cross-sectional view schematically showing a conventional waste melting furnace. Waste is charged together with a massive carbon-based combustible material from an inlet at the upper part of the waste melting furnace having the shaft part 1, morning glory part 2 and furnace bottom part 3, and oxygen is supplied from a plurality of lower tuyere 4 provided at the lower part of the furnace. A source is supplied, and ash and non-combusted matter in the waste melted by reaction heat are discharged from the discharge hole 5 at the bottom of the furnace. The bottom 3 of the waste melting furnace is formed in a cylindrical shape smaller than the diameter of the shaft 1.
JP-A-8-94035

  In a conventional waste melting furnace, for example, when a waste having a small particle diameter such as shredder dust is generated and waste having a high ash content is processed, there are the following problems.

  a. In order to prevent the in-furnace residue from fluidizing, it is necessary to increase the diameter of the furnace and reduce the superficial velocity of the furnace.

  b. In order not to form the furnace core (furnace bottom inactive part) at the furnace bottom, measures must be taken such as 1) increasing the total amount of oxygen blown to the furnace bottom, and 2) reducing the furnace bottom.

  When the measure a is taken, the superficial velocity becomes slow, but the bottom of the furnace becomes large, so the measure b cannot be taken, and a furnace core is formed at the bottom of the furnace. Therefore, at present, there is no technology related to a furnace structure that satisfies both of these simultaneously.

  Thus, the present invention provides a bottom structure of a waste melting furnace that prevents the residue of the carbonization residue in the furnace from scattering due to an increase in the superficial velocity of the furnace, prevents the formation of the furnace core, and discharges the molten material properly. Is.

In the present invention, a bottom of the furnace is formed following an inclined morning glory located at the lower part of the shaft part, a lower tuyere is disposed at the bottom of the furnace, a discharge hole for discharging a melt is formed, and the upper part of the furnace is formed. Waste (including shredder dust, etc.) and bulk carbon-based combustible materials such as coke, oxygen source from the bottom of the furnace, and melted by reaction heat from the discharge hole at the bottom of the furnace In a waste melting furnace that discharges combustion products and discharges gas generated from the top of the furnace,
(1) The shaft diameter is D1, the upper furnace bottom diameter (the diameter immediately above the installed bottom tuyere) is D2, the lower furnace bottom diameter is D3, and the cross-sectional areas at each part are S1, S2, S3, respectively. And having a furnace bottom structure that satisfies D1>D2> D3 and satisfies S1>S2> S3. (2) In the waste melting furnace of (1), the tip of the lower tuyere from the hearth part. Having a furnace bottom structure that satisfies 0.3 ≦ h / D3 ≦ 0.6, where h is the height to the core of (3) In the waste melting furnace of (1), the lower furnace (4) In the above (3), it has a furnace bottom part structure in which the tuyere is inclined downward. To do.

  Like the furnace bottom structure of the present invention, the diameter directly above the tuyere can be used to prevent the incineration residue from being scattered due to the increase in the in-core superficial velocity. The combustibility in the combustion chamber can be improved.

  Moreover, since the furnace bottom diameter of the lower part of the tuyere is reduced, formation of the furnace bottom inactive site can be suppressed. By these two measures, it becomes possible to simultaneously achieve stable operation of the melting furnace by suppressing fluidization, improvement of combustion chamber combustibility by reducing the amount of residual carbonization residue, and proper discharge of the melt.

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

  FIG. 1A is a schematic view showing a bottom structure of a waste melting furnace according to the present invention, and FIG. 1B is an enlarged view of the bottom of the furnace. A furnace bottom portion 3 is formed following the inclined morning glory portion 2 located at the lower portion of the shaft portion 1, and a lower tuyere 4 is disposed in the furnace bottom portion 3, and a discharge hole 5 for discharging the melt is formed. . The furnace bottom 3 includes an upper furnace bottom 3 a following the morning glory 2 and a lower furnace bottom 3 b from the lower tuyere 4 to the hearth 6.

  In FIG. 1, the diameter of the shaft portion 1 is D1, the cross-sectional area is S1, the diameter of the upper furnace bottom 3a above the lower tuyere is D2, the cross-sectional area is S2, and the diameter of the lower furnace bottom 3b is D3, When the cross-sectional area is S3, the diameter at each part satisfies D1> D2> D3, and the cross-sectional area satisfies S1> S2> S3. By adopting a structure that satisfies the above conditions, the superficial velocity at the upper part of the lower tuyere (cross-sectional area S2) can be kept low, and fluidization of the in-furnace residue can be suppressed. Further, by reducing the cross-sectional area S3, it is possible to increase the combustion load at the bottom of the lower furnace, and to suppress the formation of the furnace core.

  In addition, when the height from the hearth 6 to the core at the tip of the lower tuyere 4 is h, the furnace structure satisfies 0.3 ≦ h / D3 ≦ 0.6. Satisfying this equation is preferable in terms of the reach region condition of the blown gas flow at the bottom of the furnace, the heat balance, and the uniform combustibility of the coke. During implementation, the upper part of the tuyere may be covered with a refractory to protect the tuyere. In this case, since the tuyere upper refractory part is considered as the lower furnace bottom part, the inner diameter and the cross-sectional area of this part are not included in D2 and S2, respectively, and become D3 and S3.

  The height from the hearth to the core of the tip of the lower tuyere is h, but when the upper part of the tuyere is covered with refractory to protect the tuyere, from the hearth to the upper end of the refractory above the tuyere Is sometimes called h.

  As shown in FIG. 1 (b), the tuyere is located at the uppermost stage of the lower furnace bottom, and this tuyere is inclined toward the hearth by about 5 ° to 25 °. By tilting, the oxygen blown to the hearth reaches the hearth, and the formation of the core can be prevented.

The test was performed under conditions 1 to 3 shown in Table 1. A furnace bottom having a structure as shown in FIG. 2 was manufactured and tested so as to satisfy Condition 3 which is an example of the present invention. As the object to be treated, shredder dust, which is a high ash content and fine-grained material, was used.

  Condition 1: Because the cross-sectional area at the bottom of the furnace is small, formation of the furnace core is prevented, and the melt can be discharged appropriately. However, because the cross-sectional area directly above the tuyere is small, a fluidization phenomenon in the furnace occurs. Scattering of the inner dry distillation residue and flammability deterioration in the combustion chamber occurred.

  Condition 2: In-furnace fluidization phenomenon that occurred in Condition 1 did not occur when the furnace bottom diameter was increased, but because the furnace bottom cross-sectional area was too large, the inactive part (furnace core) in the hearth part Was formed, making it difficult to properly discharge the melt.

  Condition 3: By increasing the cross-sectional area (S2) immediately above the tuyere and making the cross-sectional area (S3) of the hearth part smaller than S2, fluidization in the furnace is prevented, and the core Formation was also prevented. As a result, stable discharge of the melt could be maintained while continuing stable operation of the melting furnace.

  Under condition 3, the fluidization phenomenon of the in-furnace residue was not confirmed. This is thought to be because the superficial velocity in the furnace was kept below the fluidization start speed of the residue in the furnace. In addition, at the bottom of the lower furnace, in-furnace inert portions such as the core of the furnace were not formed, and the melt could be discharged properly during the test period. It is thought that the blast oxygen vanishing point is closer to the furnace center and the hearth by maintaining the combustion load at the lower furnace bottom high.

  From the above results, it has been confirmed that the technology in this patent is effective in waste treatment with high ash content and small particle size such as shredder dust.

(A) is the schematic which shows the furnace bottom part structure of the waste melting furnace by this invention, (b) is an enlarged view of a furnace bottom part. It is a figure which shows the structure of the furnace bottom of the conditions 3 of an Example. It is sectional drawing which shows the furnace bottom part structure of the conventional waste melting furnace.

Explanation of symbols

1: Shaft part 2: Morning glory part 3: Furnace bottom part 3a: Upper furnace bottom part 3b: Lower furnace bottom part 4: Lower tuyere 5: Discharge hole 6: Hearth

Claims (4)

A furnace bottom is formed following the inclined morning glory located at the lower part of the shaft, and a lower tuyere is disposed at the bottom of the furnace, and a discharge hole for discharging the melt is formed. Waste melting that charges bulk carbon combustible material, supplies oxygen source from the bottom of the furnace, discharges ash and non-combustible waste from the discharge hole at the bottom of the furnace, and discharges gas generated from the top of the furnace In the bottom structure of the furnace,
When the shaft diameter is D1, the upper furnace bottom part diameter is D2, the lower furnace bottom part diameter is D3, and the cross-sectional areas at each part are S1, S2, and S3, the diameters at each part satisfy D1>D2> D3. , S1>S2> S3. A bottom structure of a waste melting furnace characterized by having a structure satisfying S1>S2> S3.   2. The structure according to claim 1, wherein the height from the hearth to the core at the tip of the lower tuyere is defined as h satisfying 0.3 ≦ h / D3 ≦ 0.6. The bottom structure of a waste melting furnace.   The furnace bottom part structure of a waste melting furnace according to claim 1 or 2, further comprising a tuyere at the uppermost part of the bottom part of the lower furnace.   4. The bottom structure of a waste melting furnace according to claim 1, wherein the tuyere is inclined downward.

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