JPS63197897A - Cleaning device in rotary regenerative heat exchanger - Google Patents

Abstract

PURPOSE:To improve cleaning effect and save an injection medium and an injecting time by a method wherein some thermal conducting elements divided at a plane perpendicular to a rotary shaft are arranged around the rotary shaft, an injection pipe is arranged between the thermal conducting elements and the pipe is made to communicate with a fluid passage arranged at a central part of the rotary shaft. CONSTITUTION:An injecting pipe 19 having a fluid injection hole 18 is arranged at an intermediate part of thermal conducting elements 4, 5 and 6 of each of layers. With this arrangement, an interface part between a low temperature element 4 and a medium temperature element 5, an interface part between the medium temperature element 5 and the hot temperature element 6 and a central part of the thermal conducting element 3 from each of both end surfaces are easily and easily cleaned. If each of communicating pipes 21 of injected medium is independently arranged, only the minimum required location can be cleaned. Further, a changing-over of the communicating pipe 21 enables several kinds of injection media can be utilized. In this way, an efficient and effective cleaning is carried out under a cleaning of an inner surface of each of the layers in the thermal conducting elements 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application relates to a device for cleaning heat transfer elements in rotary regenerative heat exchangers.

2. Description of the Related Art Conventionally, a rotary regenerative heat exchanger installed in, for example, a boiler is provided to exchange heat between exhaust gas and a feeder to raise the temperature of the feeder. The 1st tally is shown in Figures 3 and 4.
As shown in the figure.

The rotary regenerative heat exchanger 6 includes a heat transfer element 3 partitioned by a number of partition plates 2 in a cylindrical casing 1.
is provided. The heat transfer element 3 consists of three layers,
The heat transfer elements in each layer are classified as a low temperature element 4, a medium temperature element 5, and a high temperature element 6 in order from the lowest temperature zone. The rotor 8 rotates in the direction of the arrow around the rotation 1i117.

On the right side of this rotor 8, an exhaust gas duct 9 has been eDed, and on the left side, a mass duct 10 has been temporarily restored.

Here, the temperature of the heat transfer element 3 is raised by the heat of the exhaust gas flowing through the exhaust gas duct 9, and the heated heat transfer element 3 rotates and moves to the observation duct 1-10 field 11,
Raise the temperature of the air space.

However, in such a rotary regenerative heat exchanger,
Due to the passage of the exhaust gas, the V exhaust gas, the box, etc., adheres to the heat transfer element 3, etc., eventually causing the heat transfer surface to close, and the boiler plant to be unable to operate continuously. Therefore, it is necessary to shut down the plant, clean the rotary regenerative heat exchanger, and remove the debris.

There is a water washing device. Note that the water washing device cannot be used unless it is cold.

As shown in Figures 3 and 4, each device has two types, a swinging type and a stationary type. The heat transfer element 3 is cleaned as the rotor 8 rotates.

- ten thousand, the stationary device 15 has a plurality of spray nozzles 16;
A single pipe 17 with attached heat transfer elements 3 is arranged in the radial direction of the rotor 8, and as the rotor 8 rotates, all the heat transfer elements 3 are evenly cleaned.

Note that both devices are installed outside the rotor 8 and inject the injection medium from both end surfaces of the rotor of the heat transfer element 3 toward the center.

Problems to be Solved by the Invention As mentioned above, in the conventional cleaning group [tH1], since cleaning could only be done from the rotor bulge of the heat transfer element 3, the effect inside the heat transfer element 3 is far away from the end surface. Accordingly, the cleaning effect decreases rapidly, especially at the boundary between the heat transfer elements, so that there is a problem that it is difficult to sufficiently clean the center portion of the heat transfer element 3.

In particular, as shown in Fig. 5, the case where a denitrification device is installed upstream of a rotary regenerative heat exchanger will be explained.
The boiler 18 includes a combustion/4 exhaust gas duct 9 and a combustion air duct 10, and the exhaust gas duct 9 is equipped with a denitrification device 19 that uses NH as a reducing agent.

In addition, the exhaust gas duct 9 of the denitrification device 19 also flows 1t40.
A rotary regenerative heat exchanger 1' for exchanging heat between the denitrified gas and the combustion air is installed between the denitrified gas and the air duct 10. It is supposed to be released.

Here, in the denitrification device 19 using NH3 as a reducing agent, NOx in the combustion exhaust gas is reduced to 6NO+ 4NH,M 5N +6H206NO+8N
HM 7N2+ is decomposed into N2 and N20 by a chemical reaction such as 12H20, but NT(, (l'') enters the heat exchanger 1+ from the denitrification device 19. without reacting, and this unreacted The reaction NH, is S in the exhaust gas
05 reacts with heat exchanger 11, becoming ammonium sulfate, acidic ammonium sulfate, etc., which somehow closes in medium temperature element 5, so the shape of the heat transfer element is changed to a heat transfer element with a high cleaning effect. I had no choice but to do it. Therefore, there was a drawback that the heat transfer element became longer due to the decrease in heat transfer efficiency, resulting in an increase in cost.

What the invention seeks to solve is therefore that a sufficient cleaning of the central part of the heat transfer element is not possible, and in particular
The problem is that boilers equipped with denitrification equipment have to be shut down frequently due to clogging of rotary regenerative heat exchangers by acidic ammonium sulfate (lζ).

Means for Solving the Problems In order to solve the above problem, the present invention installs divided heat transfer elements perpendicular to the rotational axis around the rotational axis, and connects the divided heat transfer elements between the divided heat transfer elements. This invention provides a rotary regenerative heat exchanger characterized in that an ejection pipe having a fluid ejection hole is disposed in the rotary shaft, and the ejection pipe is communicated with a fluid passage provided in a narrow part of the rotating shaft.

Function The present invention provides a jet pipe that shoulders fluid jet holes at the bottom of the groove as described above, that is, between the heat transfer elements of each layer. The heat transfer element is easily cleaned directly from the boundary with the element toward both end faces of the heat transfer element.

Furthermore, if each of the communication pipes for the injection medium is made into a single pipe, it would be possible to perform partial cleaning at the minimum required location.

Furthermore, by switching the communication piping for the injection medium, it is possible to use multiple types of injection media. That is, there are no restrictions on the injection medium used for cleaning, and for example, water, air, steam, etc. can be used properly, and one injection device can be used for both purposes.

In this manner, each layer of the heat transfer element is cleaned from the same side, thereby providing efficient and effective cleaning.

Actual Case An example of an actual gun of the present invention will be explained below with reference to FIGS. 1 and 2. Note that the same components as those of the conventional rotary regenerative heat exchanger described above are designated by the same reference numerals, and detailed explanations will be omitted. Heat transfer element 3 divided along a plane perpendicular to 1117
From the lower 10,000 to the lower temperature zone, add low temperature element 4, medium temperature element 5, high temperature Elen/Toro around rotation @7. For the high temperature element 6, which is less likely to corrode in the high temperature part, a DU element such as an aluminum joint, which has extremely good heat transfer efficiency, is used. NF, such as fluororesin-treated steel, has poor thermal efficiency but excellent cleaning effect.
Rotor 8 that rotates inside the housing using an element
is being loaded.

A jet pipe 19 having a large number of fluid jet nozzles I8 is arranged between each of the divided heat transfer elements 3. Spout pipe 1
9 is a piping block 20 made of pipe material in the shape of a grid.
to form. Then, the ejection pipe 19 is connected to the rotating shaft 7 so as to be communicated with a communication pipe 21, which is a fluid passage that passes directly through the axial center of the rotating shaft 7.

In addition, it is suitable that the piping block 20 is arrange|positioned for every heat transfer element 3 partitioned off by each partition plate 2.

Also, provide a swivel joint 22 for the luck that penetrates the rotation @7, the bribe ♂ 21.

With the above configuration, the connecting pipe 21 as shown in the arrow shown in FIG.
A fluid, for example water, flows through the I mass tube 19 consisting of the self-tube block 20, and is ejected from the mass nozzle 18), and the ash, S, adhering to the heat transfer element 3 is
Clean Ox etc.

Effect of light cutting As explained above, the present invention has the following effects.

+11 Since the ejection pipe is placed between the heat transfer elements of each layer, the cleaning effect is improved and it is effective as a countermeasure against clogging of the medium temperature element by acidic ammonium sulfate or the like.

(2) Since the end faces of the heat transfer elements of each layer can be cleaned individually, if operated efficiently, the injection medium and time ri can be saved. Further, when the temperature conditions are low, it is also possible to wash only the low temperature element with water during operation in a hot state within a temperature range where there is no influence of thermal deformation.

(3) Since multiple types of spray media can be used, conventionally both a suit prower and a water washing device were required for cleaning, but the cleaning device of the present invention is convenient because it can be used for both devices.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional perspective view showing a part of a rotor of a rotary regenerative heat exchanger equipped with a cleaning device according to the present invention;
The figure is a plan view showing the piping block of the jet pipe, Figure 3 is a schematic side view of a conventional rotary regenerative heat exchanger, Figure 4 is a schematic front view thereof, and Figure 5 is a rotary regenerative heat exchanger. 1 is a schematic diagram of a combustion scum treatment system for a boiler equipped with a boiler. 3. Heat transfer element, 4. Low temperature element, 5.
Medium temperature element, 6...High temperature element, 7...Rotating shaft, 8...Rotor, 18...Fluid ejection hole, 19...Ejection pipe, 20...Piping block, 2]...Connecting pipe. Figure 1 No. 7: Reach-Kikan Figure 3 Figure 4 ゛χ

Claims (1)

[Claims] A heat transfer element divided in a plane perpendicular to the rotation axis is attached around the rotation axis, a jet pipe having a fluid jet hole is arranged between the divided heat transfer elements, and the jet pipe is connected to the axis of the rotation shaft. 1. A cleaning device for a rotary regenerative heat exchanger, characterized in that the cleaning device is connected to a fluid passage provided in a rotary regenerative heat exchanger.