JPS62258994A - Rotary regenerative heat exchanger - Google Patents

Abstract

PURPOSE:To prevent contamination of clean gas due to dust and to keep a fluctuation in a differential pressure, produced between two gases, at a specified value or less, by a method wherein, when gas containing dust is introduced to a heat transfer element, dust is collected by means of a filter to prevent adhesion of dust to a heat transfer element body. CONSTITUTION:A part of a filter 28 faces a hood 15, and low temperature gas containing dust is introduced from the hood 15 in a state that another part faces a hood 18, and high temperature clean gas is introduced from the hood 18. During passage of the gas containing dust, introduced from the hood 15, through the filter 28, dust is collected to produce clean gas. After the clean gas passes a heat transfer element 26 and is heated, it is brought into contact with a catalyst layer 27 to change a noxious component into a harmless component, and is increased in temperature to cause it to flow from a hood 16. This constitution prevents dust from adhesion to the heat transfer element body 26 and the catalyst layer 27, resulting in prevention of the occurrence of a state in which the heat transfer element body 26 and the catalyst layer 27 are closed and a pressure loss is increased due to dust.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a rotary regenerative heat exchanger suitable for heat exchange of dust-containing gas.

"Prior Art and its Problems" Rotary regenerative heat exchangers are generally known that circulate a heated gas through a heat transfer element to exchange heat with the heated gas. This rotary regenerative heat exchanger is usually

Although this method has been applied to clean gases, if it were applied to dust-containing gases, a 3N state would occur in which the dust in the dust-containing gases would adhere to the heat transfer element. For this reason, in the past, the adhesion of dust to the heat transfer surface was avoided by blowing off the adhering dust intermittently or continuously with a suit blower.

However, even if the dust is removed using the suit blow, if the dust is a substance that has high chemical reactivity with the heat transfer element, it may react with the heat transfer element and become stuck before the suit blow is performed. . Once such reaction sticking progresses, it is no longer possible to remove dust by suit blowing, and the dust accumulates on the heat transfer surface, leading to an increase in pressure loss, and not only corrodes the heat transfer surface, but also damages the element itself. Occasionally, it may become blocked by dust.

This is even more serious when the heat transfer element has a catalyst in whole or in part, or is made from a catalytic material for the purpose of removing harmful components from dust-containing gases. It becomes. In other words, the catalyst is functional.

It is formed so that the contact area with the gas is large.
Since the reaction activity is usually high, the reaction and fixation of the guest to the heat transfer surface occurs quickly, which also promotes clogging of the heat transfer element.

Additionally, it has been known for some time that dust-containing gases are removed using a separate dust removal device such as an electric precipitator or scrubber before being introduced into the heat exchanger, but this method can be used for electric collectors 1"j a. There is a limit to the temperature range, and scrubbers that hit with water lower the gas temperature, which poses a problem in terms of energy conservation.Among dust collectors, the Lou β type and the Cyclono type have a limit of M1 and the dust particle size that can be collected. Since there is a limit to the collection efficiency, a filter type is generally used, but a filter type installed outside the heat exchanger is used to keep the pressure loss caused by dust adhering to the filtration surface below a certain value. , it is necessary to perform backwashing.Therefore, it becomes necessary to stop the process gas intermittently, and as a result of the pressure loss fluctuating, the differential pressure between the dust-containing gas and the clean gas constantly fluctuates.

This means that in a rotary regenerative heat exchanger, the amount of leakage between the internal gases constantly fluctuates, and in a method that incorporates a catalyst into the heat transfer element for the purpose of removing harmful components, the amount of leakage between the internal gases changes constantly. A problem arises in that the concentration of harmful components in the outlet gas fluctuates in response to leakage fluctuations.

``Object of the Invention'' The present invention has been made to solve the above-mentioned problems, and its purpose is to substantially prevent dust in a dust-containing gas from coming into contact with a heat transfer element. That is, before the dust-containing gas is introduced into the heat transfer element, dust is collected to prevent dust from adhering to the heat transfer element, and the collected dust is backwashed and removed using backwashing gas. The purpose of this is to suppress fluctuations in the differential pressure that occurs between the internal gases to below a certain value, and further to prevent the collected dust from being mixed into the clean gas.

"Summary of the Invention" In order to achieve the above object, the rotary regenerative heat exchanger according to the present invention includes a heat transfer element partitioned into a plurality of sectors, and a gas introduction and/or gas outlet reservoir facing the heat transfer element. A rotary regenerative heat exchanger which exchanges heat between a heated gas and a heated gas via the heat transfer element by relatively rotating the heat transfer element and the header. At least one of the heated gas and the heated gas is introduced into the rotary regenerative heat exchanger as a dust-containing gas, and each of the sectors is arranged such that the dust-containing gas introduction [1 side end face of the heat transfer element] It is characterized in that it is equipped with a filter, and that the inlet and/or outlet of the backwashing gas of the filter described in 111j is made to face the heat transfer element.

Due to the presence of this filter, dust caused by dust-containing gas is
This prevents dust from reaching the heat transfer element body. The filter of each sector with dust is
The dust is sequentially and continuously backwashed by the backwashing gas flowing through the backwashing gas inlet facing the heat transfer element and/or through the outlet ITI, and the dust is collected, for example, in a separate guest hopper. It is discharged from the system by being washed away.

The cleaned filter will eventually come out to the clean gas flow path side. Therefore, fluctuations in pressure loss occurring in the filter can always be kept below a constant value, and the differential pressure generated between internal gases can be kept to a minimum.

According to one preferred embodiment of the present invention, the inlet and/or outlet for the backwashing gas is provided at a boundary between the heated gas flow path and the heated gas flow path. Therefore, a filter that has been flushed with dust-containing gas and has dust on it is sequentially flushed with backwashing gas to remove dust before it comes into contact with clean gas, so even if it then comes into contact with clean gas,
This clean gas is not contaminated by dust.

"Embodiments of the Invention" Specific embodiments of the present invention will be described in detail below with reference to the drawings.

In FIGS. 1 and 2, 11 is an outer casing of the rotary regenerative heat exchanger, which is formed into a cylindrical shape as a whole. A seal portion 1 is provided at the lower end of the outer casing 11.
A foot 15, a hood 37, and a hood 18, which are mutually partitioned by 2, are provided in this order along the rotational direction of the inner casing 22. Also external casing】1
Similarly, a hood 16, a hood 38, and a hood 17 are sunk in the L end of the hood, corresponding to the hood 15, the hood 37, and the hood 18, respectively. Therefore, each of these hoods is provided facing the heat transfer element described below.

The hood 15 introduces the heated gas containing dust 44j1
1. The hood 16 is used for discharging the heated gas, the hood 17 is used for introducing the heated gas, and the hood 18 is used for discharging the heated gas, and each of them is provided as a header. The hood 38 is used for introducing backwashing gas, and the hood 37 is used for discharging backwashing gas.

The gas to be heated and the heating gas flow in opposite directions. These two gases may be from the same system or from different systems, but in this embodiment it is assumed that dust-containing gas is introduced from the hood 15 and clean n-gas is led out from the hood 18. .

Also, food! 6 and the hood 17 are communicated by a duct 41, which is a preferable embodiment, but such communication is not essential in the present invention.

The outer casing 11 has a sealed bearing 19 in its center.
A rotating shaft 20 is inserted through the rotating shaft 20.
is connected to a drive source such as a motor (not shown). The seal bearing 19 performs a role of sealing between the outer casing 11 and the rotating shaft 20, and also allows the rotating shaft 20 to rotate smoothly.

An internal casing 22 is fixed to the rotating shaft 20,
The inner casing 22 and the outer casing 11 are sealed by a sealing mechanism (not shown). As a result, the internal casing 22 rotates in conjunction with the rotating shaft 20 while ensuring the required sealing performance with each hood.

A heat transfer element partitioned into a plurality of sectors with a fan-shaped cross section by a partition plate 25 is fixed within the internal casing 22 . Heat transfer element〉・T is the heat transfer element body 28
, the gases flowing in opposite directions, which are composed of the catalyst layer 27 and the filter 28, are heated or cooled when passing through the heat transfer element main body 28, and reach the respective outlet hoods 18 and 18. .

-L of the heat transfer element body 26 within the inner casing 22
A portion is a catalyst layer 27 on which an oxidation catalyst is supported. This catalyst layer 27 is provided to completely burn harmful components such as carbon dioxide and hydrocarbons in the gas, raise the temperature of the gas, and render the gas harmless.

In the inner casing 22 to which the heat transfer element main body 26 and the catalyst layer 27 are fixed, a filter 28 is provided on the lower side of the heat transfer element main body 2B in each sector.
is provided. The filter 28 is for collecting dust before the dust-containing gas passes through the heat transfer element main body 2B and preventing dust from adhering to the heat transfer element main body 2B and the catalyst layer 27. be.

This filter 28 is usually formed into a plate shape in applications where there is no need to take pressure loss or dust collection efficiency into account in the sense that only coarse dust needs to be collected. In applications where it is necessary to minimize loss or increase dust collection efficiency, the following configuration is preferable.

For example, in the example shown in FIG. 3, the filter 28 is preferably composed of a filter cloth 29 having excellent heat resistance and a filter cloth support 30 that supports the filter cloth, and a distance is maintained in the vertical direction between the partition plates 25. The filter cloth 23 is hung like a bellows on the filter cloth support 30 which is fixed to the filter cloth support body 30.

Further, in the example shown in FIG. 4, a perforated tube plate 32 having a plurality of gas passage holes 31 and porous tube support holes 39 is attached to the upper part between the partition plates 25. A porous tube 33 having a filter function with one end closed is inserted into the porous tube support hole 39 of the heat transfer element main body 26 .
Insert the tube so that it faces toward
2, and the open portion of the porous tube 33 is inserted into the lower tube plate 34 in a dust-tight manner.

Further, in the example shown in FIGS. 5 and 6, a porous honeycomb body 35 having a filter function is formed, one of each cell 3B of this honeycomb body 35 is opened, and the other is closed, and the closed part Alternatively, the open portion may have a checkered pattern.

In each of these filters 28, the dust-containing gas flows as shown by the arrows, so that the lI! The over area is increased and the over resistance is reduced.

When the dust-containing gas is passed through the filter 28 as shown in I-, dust adheres thereto and pressure loss increases.

In order to prevent this and backwash the dust, a backwashing gas such as air or water iris is introduced into the heat transfer element from the hood 38. This backwashing gas passes through the filter 28 in the opposite direction to the direction in which the dust-containing gas is introduced, and at that time, the attached dust is removed from the filter 28 and discharged from the foot 37 to the outside of the system.

The inlet static pressure of the backwash gas is O0 from the inlet static pressure of the heated gas.
It is preferable that the pressure is higher than 1 atm from the viewpoint of dust removability.

It should be noted that the hood 37 may have a fan-shaped opening angle larger than 1 sector, but from the viewpoint of minimizing the reduction in effective heat transfer area, the hood 37 may have an opening angle of 1 sector as shown in FIG. It is preferable to set it to an angle or smaller.

1. Effect" Next, the present invention configured as described above will be explained in detail.

Now, a part of the filter 28 is facing the hood 15, and another part of the filter 28 is facing the hood 18, and low-temperature dust-containing gas is introduced from the hood 15, and high-temperature clean gas is introduced from the hood 18. has been derived. When the dust-containing gas introduced from the hood 15 passes through the filter 2B, the dust is collected by the filter 28, becomes clean gas, passes through the heat transfer element main body 2B, and then passes through the heat transfer element main body 2B.
After being heated by the catalyst layer 27, the harmful components are rendered harmless, the temperature is further raised, and the fluid flows out from the hood 1B.

Therefore, dust does not adhere to the heat transfer element main body 26 and the catalyst layer 27, and as a result, situations such as clogging of the heat transfer element main body 2B and the catalyst layer 27 and an increase in pressure loss due to dust can be avoided. Furthermore, reduction in activity of the catalyst layer 27 due to dust can be avoided.

In this embodiment, the high temperature clean gas flowing out from the hood 1B is introduced from the hood 17 into the heat transfer element again. The thus introduced clean gas contacts the catalyst layer 27 to further completely detoxify the remaining harmful components, passes through the heat transfer element body 26, heats the heat transfer element body 26, and passes through the filter 28. and flows out from the second door 18.

Incidentally, the one-rotation shaft 20 is continuously rotated, and therefore the heat transfer element main body 2B and the filter 28 rotate in conjunction with the rotation shaft 20. Due to this rotation, the part of the filter 28 that had previously collected dust on the introduction side of the dust-containing gas is made to face the hood 37 in each sector one after another, with dust still attached to one side of the filter, and take countermeasures. Backwashing gas introduced from the hood 38 passes through this portion from the back surface of the filter 28. At that time, the dust is backwashed and removed? - It will be discharged to the outside of the system together with the backwashing gas through the door 37. Note that a part of the clean gas derived from the hood 16 can also be used as the backwashing gas.

Each part of the filter 28 that has been cleaned in this manner will eventually move toward the clean gas side through rotation, so that dust will not contaminate the clean gas.

In this way, since the filter 2B rotates continuously together with the heat transfer element main body 26, the dust collected from the dust-containing gas is removed sector by sector by the backwashing gas, thereby reducing the pressure generated in the filter 2B. It is also possible to keep fluctuations in losses below a certain value.

"Another Embodiment of the Present Invention" In each of the above embodiments, the outer casing is fixed and the heat transfer element rotates, but the heat transfer element is fixed and gas introduction and/or gas The present invention may be applied to a rotary regenerative heat exchanger having a configuration in which a hood for extraction rotates.

Further, in the above embodiment, the hood 1B and the hood 17 are connected by the duct 41, but instead of this, the duct 41 may be omitted and another gas may be introduced from the hood 17.

At this time, the gas introduced from the hood 17 may be 7+'i clean gas or dust-containing gas.

When this is a dust-containing gas, a filter is also installed on the -1- side of each catalyst layer 27 in each sector (on the t side of the heat transfer element main body 26 if the catalyst layer 27 is not provided), and An inlet for backwashing gas for the filter provided on the upper side is provided in the hood 18, this inlet, and the hood 15 along the rotational direction of the internal casing 22, and/or is provided on the E side. A gas outlet for backwashing the filter is connected to the hood 17 along the rotational direction of the inner casing 22, and this outlet is connected to the outlet.

It is preferable to provide the hood 18 in this order.

Furthermore, passing the heating gas and the heated gas in the same direction,
The resultant gas may be used as the heated gas and the clean gas may be used as the heated gas, or the catalyst layer 27 may not be provided.

"Effects of the Invention" As explained above, according to the present invention, when dust-containing gas is introduced into the heat transfer element, the dust can be first collected by the filter, so that the dust can be collected in the heat transfer element body etc. Only clean air without dust is allowed to flow in, which prevents dust from adhering to the heat transfer element body, and if the heat transfer element also has a catalytic function, poisoning of the catalyst is also avoided. It will be done.

In addition, the filter with dust attached is rotated so that each sector faces the inlet and/or outlet of the backwashing gas, so that it is continuously backwashed by the backwashing gas, and the dust is removed from the system. Therefore, the clean gas is not contaminated by dust, and fluctuations in the differential pressure between the two bodies can be suppressed to below a certain value.

Furthermore, as described above, the present invention also provides various effects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view taken along the line II--II in FIG. 2 showing an embodiment of the rotary regenerative heat exchanger according to the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view showing an example of the filter portion in the present invention, FIG. 4 is a cross-sectional view showing another example of the filter portion in the present invention, and FIG. 5 is a cross-sectional view showing yet another example of the filter portion in the present invention. The top view, FIG. 6, is a sectional view taken along the line Vl--Vl in FIG. 5. 11... External casing, 20... Rotating shaft, 22...
...Inner casing, 25...Partition plate, 26...Heat transfer element main body, 27...Catalyst layer, 28...Filter, 29...II! Cloth, 30...Symptomatic cloth support,
31... Gas passage hole, 32... Perforated tube plate, 33...
・Porous tube, 34...tube sheet, 35...honeycomb body,
36...Cell, 15.18.17.18, 37.38
...Hood. Figure 3 Stem Figure 2 Tewane City IE Book June 1986 (3rd)

Claims (4)

[Claims] (1) A heat transfer element partitioned into a plurality of sectors and a header for gas introduction and/or gas ejection facing the heat transfer element, the heat transfer element and the header rotating relative to each other. In the rotary regeneration type heat exchanger that exchanges heat between the heated gas and the heated gas via the heat transfer element, at least one of the heated gas and the heated gas is treated as a dust-containing gas during this rotational regeneration. each sector is provided with a filter on the end face of the heat transfer element on the dust-containing gas inlet side, and is provided with a backwashing gas inlet and/or outlet of the filter. facing the heat transfer element. (2) The rotary regenerative heat exchanger according to claim 1, wherein the outlet port for the heated gas and the inlet port for the heated gas are communicated with each other. (3) The inlet and/or outlet of the backwashing gas is provided at the boundary between the heated gas header and the heated gas header.
The rotary regenerative heat exchanger described in Section. (4) The rotary regenerative heat exchanger according to claim 1, 2 or 3, further comprising a catalyst layer on the heated gas outlet side of the heat transfer element.