JPH06174225A - Steel ball scattering type heat exchanger - Google Patents

Abstract

PURPOSE:To enhance a cleaning effect such that steel balls being scattered for removing attachment of heat-transfer pipes will not be scattered to an area except for a target area. CONSTITUTION:Provided in a heat exchanger body 1 is a group of heat-transfer pipes 2, above which a plurality of steel ball charging ports 3 are provided. Steel balls charged from the steel ball charging ports 3 are collected at a lower portion of the heat exchanger body 1 to be conveyed to an upper portion of the heat exchanger body 1 by a steel ball transporting machine 4, and are again scattered into a heat exchanger through the steel ball charging ports 3 to pass along the walls of the heat-transfer pipes of the heat exchanger while impinging against the heat-transfer pipes and falling so as to remove dust adhered to the heat-transfer pipes. Partition walls 7 are provided between the steel ball charging ports 3 and the group of heat-transfer pipes 2 to correspond to every one of the plurality of steel ball charging ports 3 and to serve as delimiting areas where steel balls charged from the steel ball charging ports 3 are scattered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a heat exchange device which is constructed such that soot and dust adhering to the surface of a heat transfer tube in a heat exchanger such as an exhaust gas economizer is sprayed and removed by a steel ball.

[0002]

2. Description of the Related Art A heat exchange device, such as an exhaust gas economizer, has been put into practical use which is constructed so as to remove soot dust adhering to the heat transfer tube surface of an exhaust gas heat exchanger containing soot dust by spraying steel balls. In this case, the amount of the steel balls to be sprayed and the spray interval are determined according to the attachment speed of the dust and the adhesion of the dust to the heat transfer tube (in other words, the dust removal property). That is, when the attachment speed or the attachment strength of the dust is large, the steel balls are continuously sprayed (or the spray pause time is shortened). Further, in this case, the dust removal power is strengthened by increasing the amount of sprayed steel balls (dispersion density) and the heat transfer performance is maintained.

In general, in this type of heat exchange device, if the heat exchanger is small, the required cross section of the steel balls is small, so only one steel ball inlet is required. Multiple steel ball inlets are installed to maintain the uniformity of the amount of steel ball sprayed per unit cross-sectional area.

FIG. 5 is a schematic system diagram of a heat exchange device to which the present invention is applied. In the figure, 1 is a heat exchanger body,
A heat transfer tube group 2 is arranged therein, and a plurality of steel ball charging ports 3 are installed above it. The introduced steel balls are collected in the lower part of the heat exchanger main body 1 and transported to the upper part of the heat exchanger main body 1 by the steel ball transporter 4, and again through the steel ball input port 3 between the heat transfer tube walls inside the heat exchanger. Soot and dust adhering to the heat transfer tube are removed in the process of passing through and colliding with the heat transfer tube and falling down.

When the steel balls collide against the upper heat transfer tube group 2 too much, a protector 13 may be placed on the upper part of the heat transfer tube group 2 to control the collision energy of the steel balls. The processing gas containing soot enters the heat exchanger through the processing gas inlet 5 and is discharged through the processing gas outlet 6. The positions of the inlet and outlet of the processing gas are switched depending on the convenience of the devices connected to the front and rear.

In the case of a large heat exchanger, a plurality of steel ball dispersers or a plurality of steel ball inlets are provided in order to reduce the transportation energy of the steel balls, and the steel balls are intermittently and periodically Part (partition) of the entire cross section of the heat exchanger (virtual division)
According to the above, it is usual to put in the orbit. In that case, the supplied steel balls hit the protector for protecting the heat transfer tube or the heat transfer tube installed on the upper surface of the inside of the heat exchanger, and diffused in a wide area. In particular, the spray density tends to decrease in the peripheral portion where the steel ball projection angle increases from the charging port.

[0007] Soot dust with a small adhesive force is less problematic,
For soot and dust with large adhesion, the soot dust removal effect cannot be exhibited unless the collision frequency of the steel balls is high, so in order to increase the distribution density of the steel balls, the steel ball circulation amount is increased to deal with it. Inevitably, this will lead to an increase in energy consumption and transportation energy. Further, when the supply amount of the steel balls is increased, the diffusion range of the steel balls is increased due to the interference and repulsion of the steel balls in the supply section, and the efficiency of supplying the steel balls to the target section is reduced. The present invention intends to effectively eliminate dust by reducing these disadvantages as much as possible and increasing the degree of concentration of steel ball spraying on the target area.

[0008]

As described above, the conventional heat exchange device in which the dust and the like adhering to the heat transfer tube is removed by spraying the steel balls has the following various problems. There is.

(1) In a large heat exchanger, the gas passage cross-section is large, and the steel balls scattered on the upper surface of the heat exchanger are diffused (dispersed) to the periphery, and the steel within a specific area is formed. The concentration of ball spraying is reduced. Therefore, the clean strength with respect to the supply amount of steel balls decreases. In addition, the uniformity of the spray density is reduced.

(2) In a large heat exchanger, the number of arrayed heat transfer tubes in the gas flow direction (height direction) is large, and the steel balls diffuse toward the lower side, so the frequency of steel ball collision with the lower heat transfer tube is reduced. The heat tube cleaning strength decreases. Diffusion on the upper surface of the heat exchanger facilitates this phenomenon.

(3) In order to enhance the cleaning strength of the steel balls, it is sufficient to increase the initial distribution density (steel ball circulation amount), but the steel ball transportation energy increases. The present invention solves these problems found in the conventional heat exchange device, has a high degree of concentration in the target area of the heat exchanger to remove dust, and efficiently disperses the steel balls to improve the clean strength of the heat transfer tube. An object is to provide a heat exchange device that can be increased.

[0012]

In order to solve the above-mentioned problems in the heat exchange device having a plurality of steel ball charging ports for spraying steel balls for removing the soot dust adhering to the heat transfer tube, the present invention aims to solve the problems. A configuration is adopted between the mouth and the heat transfer tube, in which a partition wall for limiting the spraying area of the steel balls is provided for each steel ball inlet.

That is, the upper cross section of the heat exchanger is partitioned in a box-like shape by partition walls such as vertically standing steel plates to limit the diffusion range of the steel balls. The height of the partition wall is not a constant value because the height of the steel ball jumped up differs depending on the coefficient of repulsion between the steel ball and the protector or the upper heat transfer tube, the height of the steel ball inlet, the shape of the protector, and the like. Therefore, the height of the partition wall is decided considering the maintenance of the heat exchanger and the proper height is selected. In addition, inside the partition wall, there may be more small partition wall (s)
May be placed.

[0014]

By providing the partition wall as described above according to the present invention, the steel balls scattered from the steel ball inlet into the partition can repel the surface of the heat transfer tube or the surface of the protector and diffuse over a wide area. It can be suppressed. As a result, the degree of concentration of steel balls in a certain steel ball spraying section can be kept to the maximum. In addition, the uniformity of the distribution density of steel balls in the section is increased,
Provides a uniform dust removal effect on the entire surface.

Further, by arranging a small partition wall (s) inside the partition wall, the effect can be enhanced corresponding to the characteristics of the steel ball throwing device. That is, the small partition wall has the function of further homogenizing the dispersion (distribution) of the steel balls in the large partition depending on the characteristics of the steel ball disperser or protector used.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat exchange device according to the present invention will be specifically described below with reference to the embodiments shown in FIGS. In addition,
In FIG. 1, parts equivalent to those of the conventional heat exchange device shown in FIG. 5 are designated by the same reference numerals, and description thereof will be omitted. 1 is different from the heat exchanger shown in FIG. 5 in that a partition wall 7 is arranged between the steel ball inlet 3 and the heat transfer tube group 2.

The partition wall 7 serves to limit the spraying area of the steel balls sprayed from each of the plurality of steel ball inlets 3 provided therein. That is, the partition wall 7, as is shown in FIG. 2 (a), the steel ball inlet _{n 1, n 2, ... n} n
The space above the heat transfer tube group 2 is divided so that one section is provided for each.

By providing the partition wall 7 in this manner, the steel balls scattered from the steel ball inlet 3 into the partition are provided on the surface of the heat transfer tube group 2 or for protecting the heat transfer tubes provided as necessary. It is possible to suppress the repulsive jump on the surface of the protector and spread over a wide area. As a result, the degree of concentration of steel balls in a certain steel ball spraying section can be kept to the maximum. In this way, the uniformity of the distribution density of steel balls in each section is enhanced, and the dust removal effect is imparted evenly to the entire surface.

Further, as shown in FIG. 2 (b), a smaller partition wall 7'is provided inside the partition wall 7, or as shown in FIG. 2 (c), a small partition wall 7 of squares. '' May be provided to further limit the diffusion range of the steel balls. In this way, by further disposing the small partition wall inside the partition wall, it is possible to enhance the cleaning effect of the heat transfer tube in accordance with the characteristics of the steel ball throwing device.

The height of the partition wall is the coefficient of repulsion between the steel ball and the protector or the upper heat transfer tube, the height of the steel ball inlet,
Since the height of the steel ball jumped up differs depending on the shape of the protector, etc., it does not become a constant value. Therefore, the height of the partition wall is decided in consideration of maintenance of the heat exchanger and the proper height is selected.

The results of a test for confirming the effects of the present invention using the simulation test apparatus shown in FIG. 3 will be described below. The outline of the test equipment and test conditions is as follows.

(1) Steel ball throwing device: It has a rotary feeder 9 connected to a steel ball hopper 8 and 1.3 m below it.
150mm diameter cut out from a steel 450R virtual sphere
The disk of No. 1 was installed as the steel ball disperser 10.

(2) Measurement of dispersed state of steel balls: A falling steel ball is received by a box made of plywood that is divided into a square of 25 cm in length and 2 × 2 m in length 0.3 m directly under the steel ball throwing device. The steel ball sampling device 12 is placed, and the weight of the steel balls accumulated in each box is weighed within a certain test time.

On the upper surface of the sampling device, steel pipes 11 (as heat transfer pipes) having a diameter of 38 mm are installed in two stages in a staggered arrangement with a 90 mm pitch between the pipe centers to simulate an actual device having a heat transfer pipe group. The pipe arrangement direction was parallel to the outer frame of the steel ball sampling device with the steel ball charging device directly above.

(3) Test conditions-Steel ball supply amount 500
kg / m ² · h (steel ball diameter 4.8 mm) ・ Installed so that the center of the steel ball inlet is directly above the center of one side of the steel ball sampling device.

A steel plate having a height of 200 mm is erected on the heat transfer tube and the upper part of the steel ball sampling box is a square partition wall 7 having a side of 1 m.
Experiments were carried out with and without a partition.

The test results are shown in FIG. The steel balls were supplied at a predetermined supply amount for 15 minutes, and the amount of steel balls accumulated in a square of 25 cm on a side of the steel ball sampling device 12 was weighed to obtain the steel ball dispersion density at each place. However, the steel plate dispersion density = the amount of collected steel balls in each box / the standard amount of spray to each box × 100 The standard amount of spray = total supply amount / 64 × 2 (box)

In FIG. 4, one square on each side of the steel ball sampling device dividing the steel ball sampling device into two parts (two in total).
Shows the dispersion density of steel balls calculated by averaging the amount collected by the box. In FIG. 4, the curve (1) shows the dispersion density when there is no partition wall, and the curve (2) shows the dispersion density when the partition wall is provided. From this, it can be seen that the steel balls are dispersed in a wide range when there is no partition wall, and the steel ball dispersion density tends to be low in the portion far from the charging port. On the other hand, when the partition wall 7 is attached, the steel ball dispersion density is made considerably uniform at various points in the target area.

In the case of this test, 1 m from just below the charging port
Vertical walls are provided at remote locations. That is, 2 m x 2 in the actual machine
It is imaginary to provide one steel ball inlet in the square of m. In addition, FIG. 4 shows the steel ball dispersion density calculated by averaging the amounts collected on each side of the center line that divides the steel ball sampling device into two. This is because it is difficult to obtain the absolute value of the steel ball dispersion density for each box, and therefore the reliability is increased in order to investigate the relative change.

[0030]

As described above in detail, in the heat exchange device according to the present invention, a partition wall is provided between the steel ball charging port and the heat transfer tube to limit the distribution area of the steel balls for each steel ball charging port. Therefore, with respect to the unit cross-sectional area of the upper surface of the heat transfer tube group, that portion is set as the target area, and it is possible to prevent the steel balls scattered within the unit time when the steel balls are thrown in from spreading to other areas. It is possible to secure the maximum density of steel balls sprayed to the. Therefore, when a certain amount of steel balls are sprayed, the greatest cleaning effect can be exhibited (high energy efficiency). Further, in the heat exchange device according to the present invention, the distribution of the partition walls makes the distribution density of the steel balls to the target area having the heat transfer tube group uniform, so that a sufficient dust removing effect is given to the entire target area.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a heat exchange device according to the present invention.

FIG. 2 is a perspective view showing an example of an installation situation of partition walls in the heat exchange device according to the present invention.

FIG. 3 is a side view of a test device for confirming the effect of the heat exchange device according to the present invention.

FIG. 4 is a graph of test results showing the effect of the present invention.

FIG. 5 is a sectional view showing a conventional heat exchange device.

[Explanation of symbols]

 1 Heat Exchanger Main Body 2 Heat Transfer Tube Group 3 Steel Ball Inlet 4 Steel Ball Transporting Machine 5 Processing Gas Inlet 6 Processing Gas Outlet 7 Partition Wall 8 Steel Ball Hopper 9 Rotary Feeder 10 Steel Ball Disperser 11 Steel Tube 12 Steel Ball Sampling Device 13 Protector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Suzumura 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute

Claims (1)

[Claims] 1. A heat exchange device provided with a plurality of steel ball charging ports for spraying steel balls for removing soot dust adhering to a heat transfer tube,
A steel ball-spraying type heat exchange device, characterized in that a partition wall is provided between the steel ball input port and the heat transfer tube to define a steel ball spraying area for each steel ball input port.