JPH02309111A - Construction of stack - Google Patents

Abstract

PURPOSE:To reduce constructing cost of a stack, enable the stack to be constructed in a short time and make the stack insusceptible to corrosion, by providing an external cylinder to be disposed in a stack cylinder body so as to extend along a part of the vertical dimension of the stack cylinder body, and an internal cylinder to be combined with the external cylinder. CONSTITUTION:A first flue 12 is formed of a material not resistant to corrosion or a corrosion- resistant material, and guides a non-corrosive exhaust gas into a stack cylinder body 11. A second flue 13 is formed of a corrosion-resistant material, and guides a corrosive exhaust gas into the stack cylinder body 11. An external cylinder 14 is disposed in the stack cylinder body 11, above an exhaust port 16 of the first flue 12. The outside diameter of the external cylinder 14 is smaller than the inside diameter of the stack cylinder body 11. The external cylinder 14 is disposed coaxially with the stack cylinder body 11, and has a length (height) sufficiently smaller than that of the stack cylinder body 11. Thus, the external cylinder 14 is disposed in the stack cylinder body 11 along a part of the vertical dimension of the stack cylinder body 11. The internal cylinder 15 is disposed inside the external cylinder 14 coaxially, in the manner of being surrounded by the external cylinder 14, with a gap therebetween, and in connection with the second flue 13. It is thereby possible to construct the stack in a short time, and to prevent the stack from being corroded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a chimney.

[Prior Art] FIG. 4 shows a conventional chimney structure that exhausts non-corrosive exhaust gas and corrosive exhaust gas together. In FIG. 4, 1 is a chimney barrel, 2 is a first flue for exhausting non-corrosive exhaust gas, and 3 is a second flue for exhausting corrosive exhaust gas.

Here, the non-corrosive exhaust gas passing through the first flue 2 refers to non-corrosive exhaust gas that does not contain corrosive substances, and also contains corrosive substances such as So, No, etc. However, even if the exhaust gas temperature drops during exhaust, it is said to be at a high enough temperature that it is difficult for it to fall below the dew point, and there is no or almost no condensation on the chimney, and corrosive drains do not form on the walls of the chimney. Refers to exhaust gases that are rarely seen, such as exhaust gases (air) from building dust collection systems that do not contain corrosive substances, or So, No.

It refers to exhaust gas from gas turbines, diesel engines, etc., which has a high temperature of about 150 to 200 degrees Celsius. In addition, the corrosive exhaust gas passing through the second flue 3 is
, No., etc., and which condenses on the chimney cylinder during exhaust and generates a corrosive drain. For example, exhaust gas is purified through a wet desulfurization device and then exhausted. Refers to exhaust gas from boilers, etc. that contains supersaturated moisture at around ℃.

In the conventional chimney structure, the above-mentioned two types of exhaust gases are exhausted from these two flues 2.3 together through one chimney barrel 1, but the corrosive exhaust gas is discharged from the inner wall of the chimney barrel 1. If the structure is made of non-corrosion-resistant material such as reinforced concrete or iron, the entire inner wall of the structure is lined with corrosion-resistant steel, or the structure itself is made of corrosion-resistant material. The structure is made of steel and has a corrosion-resistant structure.

[Problems to be Solved by the Invention] However, the conventional chimney structure is complicated, as it requires covering the entire inner wall of the chimney's body with corrosion-resistant steel plates and constructing the chimney with corrosion-resistant steel. ,
There were problems such as high construction costs due to the high cost of corrosion-resistant steel, and a prolonged construction period.

Furthermore, even when the chimney body is made of a corrosion-resistant structure, there is a problem that it is easily damaged due to contact with corrosive exhaust gas and requires maintenance.

The present invention has been made in view of these conventional problems, and provides a chimney that reduces construction costs, can be constructed in a short period of time, and is less likely to corrode and is advantageous in terms of maintenance. The purpose is to provide structure.

[Means for Solving the Problems] The chimney structure of the present invention for achieving the above object includes a chimney barrel and a first flue connected to the chimney barrel for exhausting non-corrosive exhaust gas. a second flue made of corrosion-resistant steel that is connected to the chimney barrel and exhausts corrosive exhaust gas; an outer cylinder made of corrosion-resistant steel that is partially internally installed with respect to the height of It is characterized by consisting of a tube.

In addition, the chimney body and the first flue shall be non-corrosion-resistant or corrosion-resistant.

Further, it is preferable that a heat insulating material is provided at least in a portion of the second flue provided inside the chimney cylinder and on the outer periphery of the inner cylinder.

[Example] Hereinafter, the present invention will be explained with reference to the drawings and examples.

FIG. 1 is a longitudinal sectional front view of a chimney structure according to an embodiment of the present invention;
FIG. 2 is also a partially enlarged view of FIG. 1.

In these figures, 11 is a chimney barrel, 12 is a first flue through which so-called non-corrosive exhaust gas passes, 13 is a second flue through which corrosive exhaust gas is passed, 14 is an outer cylinder, and 15 is an inner cylinder. be.

The chimney barrel 11 is made of non-corrosion-resistant materials such as reinforced concrete and iron, but it may be constructed from these non-corrosion-resistant materials and may also be provided with a corrosion-resistant structure such as pasting corrosion-resistant steel plates on the walls of the structure, or may be constructed by itself. It may be constructed of corrosion-resistant material such as corrosion-resistant steel.

First smoke! a12 is made of non-corrosion-resistant or corrosion-resistant material, and is used as non-corrosive exhaust gas, for example, at a temperature of 150 to 2
At 00℃, SO, a corrosive substance, along with about 8% moisture
This is to guide exhaust gas from a diesel engine or the like containing w and no into the chimney cylinder body 11. In addition, the second flue 13
is made of corrosion-resistant material and is used as a corrosive exhaust gas, for example,
After being treated with a wet desulfurization/denitrification equipment, the exhaust gas from the boiler, etc., which is at a temperature of about 60°C and contains about 20% supersaturated steam as well as corrosive substances So, No, etc., is transferred to the chimney cylinder 1. ] There are things that lead you inward.

Further, an outer cylinder 14 is installed inside the chimney cylinder body I+ at a position above the exhaust port 16 of the first flue 12. The outer diameter of the outer cylinder 14 is smaller than the inner diameter of the chimney cylinder 11, and the outer cylinder 14 is installed coaxially with the chimney cylinder 11 in the axial direction, and the outer cylinder 14 is long and high. The diameter) is sufficiently short (smaller) than the length and height of the chimney cylinder 11, so the outer cylinder 1
4 is partially installed inside the chimney cylinder 11 in terms of its height. As will be described later, this outer cylinder I4 is designed to keep the non-corrosive exhaust gas exhausted from the first flue 12 or the corrosive exhaust gas exhausted from the second flue 13 constant within the chimney cylinder I. The diameter and height of the outer cylinder 4 are appropriately determined in relation to the chimney body 11, the cylinder 15, etc.

In addition, the inner cylinder 15 is surrounded by the outer cylinder 14 and stacked coaxially with a gap inside the outer cylinder 14,
It is connected to the second flue 13 and arranged.

The outer cylinder 14 and the inner cylinder 15 are made of corrosion-resistant steel, such as sulfuric acid-resistant steel (high-grade corrosion-resistant steel) containing 30% nickel, 20% chromium, and 5% or more of molybdenum. use.

In FIGS. 1 and 2, the outer cylinder 14.20 is used to support and fix the outer cylinder 14 and the inner cylinder 15 within the chimney cylinder. A plurality of stay rods 21 are provided at equal intervals in the circumferential direction between the inner cylinder 15 and the chimney cylinder 11, and the stay rods 21 are arranged at equal intervals in the circumferential direction in the gap between the inner cylinder 15 and the outer cylinder 14. Inner cylinder 15
These are a plurality of support arms for supporting the outer cylinder 14.

In the chimney structure of the present invention, it is preferable that the flow velocity ratio between the non-corrosive exhaust gas and the corrosive exhaust gas is about 0.5 to 2 near the outlet (upper opening) of the outer cylinder 14. This is because if the flow velocity ratios of the two are extremely different, a laminar flow of the two types of exhaust gas will tend to be difficult to occur within the chimney cylinder 11, and the effects of the present invention may be reduced. Therefore, the cross-sectional areas of the outer cylinder 14, the inner cylinder 15, and the chimney cylinder 11 may be determined so that such a flow velocity ratio is achieved at the exit portion of the outer cylinder 14.

Note that even if the flow velocity ratio is not in the above range, the effects of the present invention will still be produced even if there are differences in degree.

Furthermore, as in this embodiment, when there is a temperature difference between two types of exhaust gas, the two types of exhaust gas with a large temperature difference pass between the inside and outside of the inner cylinder 15, and the inner and outer walls of the inner cylinder 5 are In order to make contact with
A heat insulating material 22 is provided to prevent moisture in the low-temperature corrosive exhaust gas from condensing.

FIG. 3 explains the state of exhaust gas exhaust in the chimney structure of the present invention having the above configuration. As shown in the figure, the flows of two types of exhaust gas are rectified to form a laminar flow and are exhausted from the chimney cylinder 11. Ru. That is, non-corrosive exhaust gas is exhausted exclusively through the outer periphery of the chimney barrel I+, and corrosive exhaust gas is exhausted through the center of the chimney barrel 11. It is.

In Figure 3, X is non-corrosive exhaust gas, Y is corrosive exhaust gas,
Z indicates a region where both are mixed.

The specific conditions in the example of FIG. 3 are as follows.

The length of the chimney cylinder 11 is 45.9 [m], and the inner diameter is 5.
．． 7 [m], the length of the outer cylinder 14 is 5 [m], the inner diameter is 3.5 [m], the length of the inner cylinder 15 is 12 [m], the inner diameter is 2.4 [rr+], the outside of the inner cylinder 15 is Diameter 2.5
4 [m], and the length from the top of the outer cylinder 14 to the top of the chimney cylinder 11 is 29.4 [m].

In each part of the chimney cylinder 11 in the length and height direction, the inner wall of the cylinder, in other words, an exhaust path for non-corrosive exhaust gas, and the central part of the cylinder 1, in other words, an exhaust path for corrosive exhaust gas. The figure shows the results of temperature measurement in the exhaust passage.

In the data, the upper value indicates the return of the inner wall of the cylinder (2), and the lower value indicates the temperature measurement result at the center of the cylinder 11.

As can be seen from this result, the inner wall portion of the chimney barrel 11 is maintained at a high temperature above the dew point, and although the non-corrosive exhaust gas in this case contains corrosive substances, it reaches the dew point during exhaust. From beginning to end, without causing any draining,
It is exhausted as non-corrosive exhaust gas, that is, without becoming corrosive exhaust gas at a temperature below the dew point, surrounding corrosive exhaust gas.

In addition, in the chimney structure of the present invention, the outer cylinder 14 in FIG.
If the length from the top of the outer cylinder 14 to the top of the chimney cylinder 11 is extremely thick compared to the length of the inner cylinder 15, on the side near the top of the chimney cylinder 11.

The laminar flow of non-corrosive exhaust gas and corrosive exhaust gas will be disturbed, and the two will mix, causing the corrosive exhaust gas to come into contact with the inner wall of the chimney cylinder 11 and generate a highly corrosive drain. It is preferable to appropriately determine conditions such as the lengths of the outer cylinder 14 and the inner cylinder 15 with respect to each length of the body 11 and the length of the chimney cylinder 11. However, even if the length from the top of the outer cylinder 14 to the top of the chimney cylinder 11 is greater than the lengths of the outer cylinder 14 and the inner cylinder 15, corrosive exhaust gases are less likely to come into contact with the inner wall of the chimney cylinder 11. In this respect, certain effects can be obtained.

Although the non-corrosive exhaust gas in the above embodiment contains corrosive substances, the same applies to the exhaust gas (air) of the building dust collection system that does not contain corrosive substances. However, since this exhaust gas does not contain corrosive substances, there is no problem even if the exhaust gas temperature is below the dew point, so the exhaust gas temperature is not an important requirement.

Furthermore, the chimney structure of the present invention can be employed not only in the case of a new chimney but also as a modified structure of an existing chimney.

[Function] According to the present invention, the existence of the outer cylinder provided partially in the height direction of the chimney cylinder and the inner cylinder provided in combination with the outer cylinder allows non-corrosive exhaust gas and corrosive exhaust gas to be separated from each other. In other words, non-corrosive exhaust gas is exhausted from the chimney body in a laminar flow so that the exhaust path is exclusively on the periphery of the chimney body, and corrosive exhaust gas is exhausted exclusively on the center side of the chimney body. will be done.

In short, non-corrosive exhaust gas is exhausted in such a way that it surrounds corrosive exhaust gas, and the non-corrosive exhaust gas comes into contact with the inner wall of the chimney barrel. This prevents the formation of corrosive acid drains caused by corrosive exhaust gases.

[Effects of the Invention] As described above, according to the present invention, by providing the outer cylinder and the inner cylinder partially made of corrosion-resistant steel inside the chimney cylinder, the occurrence of corrosive drain on the wall of the chimney cylinder can be prevented. The amount of corrosion-resistant steel used is small compared to the conventional method where the entire inner wall of the chimney cylinder made of non-corrosion-resistant material is coated with corrosion-resistant material, or the chimney cylinder itself is made of corrosion-resistant steel. The construction cost for building chimneys can be lowered.

Furthermore, since the structure is simple, it can be used not only as a new chimney structure but also as a modified structure for an existing chimney, and construction can be completed in a short period of time.

Furthermore, even when the chimney body is made corrosion resistant, the corrosion resistance is advantageous in terms of damage resistance and maintenance.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a chimney according to an embodiment of the present invention, Fig. 2 is an enlarged longitudinal cross-sectional view of the main parts, Fig. 3 is an explanatory diagram of the exhaust state inside the chimney, and Fig. 4 is a conventional It is an explanatory view of a chimney structure. ! DESCRIPTION OF SYMBOLS 1-Chimney cylinder body, 12-First flue 13-Second flue, 14-Outer cylinder 15-Inner cylinder, 15-Exhaust port 17-Upper opening, 22-Insulating material patent applicant Nastor Co., Ltd. No. Figure 1 Figure 2

Claims (1)

[Claims] 1) A chimney barrel (11), a first flue (12) connected to the chimney barrel (11) for exhausting non-corrosive exhaust gas, and a chimney barrel (11) a second flue (13) made of corrosion-resistant steel that is connected to the
1) an outer cylinder made of corrosion-resistant steel that is partially internalized relative to the height of the chimney cylinder (11) with its axial direction aligned with the upper position of the exhaust port (16) of the first flue (12) in (14), and an inner cylinder (15) made of corrosion-resistant steel, which is arranged coaxially with a gap inside this outer cylinder (14) and connected to the second flue (13). A chimney structure featuring 2) The chimney structure according to claim 1, wherein the chimney barrel (11) and the first flue (12) are made of non-corrosion-resistant material. 3) The chimney structure according to claim 1, wherein the chimney barrel (11) and the first flue (12) are made of corrosion-resistant material. 4) At least the chimney cylinder (11) of the second flue (13)
4. The structure of a chimney according to claim 1, further comprising a heat insulating material (22) arranged around the outer periphery of the portion provided inside and the outer periphery of the inner cylinder (15).