JPH0619979Y2 - Fluidized bed heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a fluidized bed heat exchanger.

2. Description of the Related Art A conventional fluidized bed heat exchanger of this type is, for example, as shown in FIG. 2, a vertically long container having a gas inlet (20a) at a lower side and a gas outlet (20b) at an upper end. (20), in the container (20), a perforated plate (22) horizontally arranged so as to partition the inside of the container (20), and an appropriate thickness on the perforated plate (22) in the container (20). And a sand layer (23) formed on the ground. Further, the container (20) is composed of a substantially U-shaped pipe, and an electric heating pipe (24) for transferring water as a fluid to be heated has its curved portion (24c) exposed to the outside of the container (20), The two parallel portions (24a) and (24b) penetrate through the container (20) and are attached so that their tip portions project to the outside of the container (20).
4a) is arranged in the sand layer (23), and the other parallel part (24b) is arranged above the sand layer (23). The tip of the one parallel portion (24a) is formed as a water intake port (25), and the tip of the other parallel portion (24b) is formed as a water intake port (26).
And the water outlet (26) is connected to hot water or a steam circulation system of a boiler (not shown), for example. Also, the parallel part
A large number of fins (27) and (27) are attached to the outer surfaces of (24a) and (24b) for efficient heat exchange.

Furthermore, a lead-out pipe (28) is connected to the gas inlet (20a),
The outlet pipe (28) is connected to, for example, an exhaust gas emission system of a diesel engine (not shown). Further, inside the outlet pipe (28), a damper for controlling the amount of exhaust gas supplied is provided.
(29) is provided. On the other hand, the gas outlet (20b) is connected to a lead-out pipe (30) internally provided with a damper (31) for controlling the amount of exhaust gas released.

Thus, during normal operation of the fluidized bed heat exchanger, the damper is
(29) and (31) operate so as to open the outlet pipes (28) and (30), respectively, and high temperature exhaust gas is introduced into the container (20) through the gas inlet (2
Pass from 0a) towards the gas outlet (20b). Then, the exhaust gas is jetted into the sand layer (23) from the lower side of the porous plate (22), and the sand layer (23) is vigorously stirred and heated by the gas flow to form a fluidized bed. At this time, the two parallel portions (24a), (24b) of the heat transfer tube (24) are both inside this fluidized bed, and the water flowing into the heat transfer tube (24) from the water inlet (25) is (twenty four)
It is heated by the fluidized bed as it passes through it, and then flows out through the water outlet (26).

On the other hand, when stopped, the dampers (29) and (31) operate so as to close the outlet pipes (28) and (30), respectively.

In such a fluidized bed heat exchanger, when the gunpas (29) and (31) are operated to open the outlet pipes (28) and (30), high temperature exhaust gas is generated. The temperature of the sand layer (23) increased considerably by stirring and the flow state of sand particles was maintained, but the dampers (29), (31) actuated to close the outlet pipes (28), (30). At times, the flow rate of exhaust gas passing through the container (20) becomes zero, and the temperature of the heat exchanger drops. And
When the temperature in the sand layer (23) becomes lower than the acid dew point of the exhaust gas remaining in the container (20), especially in the sand layer (23), the ion content in the exhaust gas, especially sulfur oxide (SO _X )But,
Similarly, it also binds to water vapor in the exhaust gas and begins to condense into anhydrous sulfuric acid, which causes the sand particles to bind to each other or stick to the surface of the heat transfer tube (24).

If such a state is left as it is, the exhaust gas does not properly fluidize the sand layer (23), and as a result, the heat exchange efficiency is significantly reduced, and further, the exhaust gas flows into the gas flow passage at the time of restart. Sand layer that does not fluidize easily when exposed (23)
However, a load may be applied to the exhaust gas flow, which may lead to system damage or the like.

Conventionally, in order to prevent condensation of anhydrous sulfuric acid, water vapor, etc. during operation of the heat exchanger, a temperature sensor is arranged at the gas outlet of the gas flow path, and the water take-out port of the heat transfer tube is provided according to the detection signal from the temperature sensor. There was a fluidized bed heat exchanger that prevented the temperature of the sand layer from decreasing by providing a means to supply a certain amount of the water flowing out from the water inlet to the water intake again. There has been no conventional technique for reliably preventing the condensation of sulfuric anhydride or the like.

Therefore, an object of the present invention is to send outside air into the sand layer during low load operation or stop of the heat exchanger.
Exhaust gas remaining in the sand layer is removed to act like a post-purge, lowering the acid dew point temperature and preventing condensation of sulfuric acid, water vapor, etc., so that the sand layer is reliably fluidized when the heat exchanger is restarted. To provide a fluidized bed heat exchanger.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a gas flow passage that allows gas to pass substantially downward and upward, and a gas flow passage arranged to block the gas flow passage. Perforated plate,
A solid particle layer formed on the perforated plate in the gas flow path, which has a top surface in an open state and can be in a fluidized state when a gas passes, and is provided on the upstream side of the perforated plate,
A damper means for controlling the flow rate of the gas, and a fluid inlet which is arranged in the gas flow passage so as to be able to come into contact with the solid particle layer in a fluidized state, and both end portions project outside the gas flow passage. And a fluidized bed heat exchanger having a heat transfer tube formed as a fluid outlet,
Between the porous plate and the damper means of the gas flow path,
The fluidized bed heat exchanger is characterized in that an outside air supply means is connected through a communication passage, and a throttle valve for controlling an air supply amount of the outside air supply means is provided in the communication passage. .

Further, in the fluidized bed heat exchanger, a fluidized bed heat exchanger is provided in which valve means is provided at a fluid inlet and a fluid outlet of the heat transfer tube.

Operation In the above configuration, the gas flow path is connected to an exhaust gas emission system of, for example, a diesel engine, and the fluid intake port and the fluid intake port of the heat transfer pipe are connected to, for example, hot water or a steam circulation system of a boiler.

When the fluid heat exchanger is normally operated and the damper means is operating to open the gas passage, the exhaust gas passes through the gas passage substantially from the bottom to the top. At this time, the exhaust gas is jetted from the porous plate into the solid particle layer, whereby the solid particle layer is vigorously stirred and heated to be in a fluidized state, and a so-called fluidized bed is formed. At the same time, the heat transfer tube comes into contact with the fluidized bed, and the fluid to be heated which has flowed into the heat transfer tube from the fluid intake port is heated by the fluidized bed and then flows out from the fluid intake port.

On the other hand, when the damper means operates so as to close the gas passage at the time of stoppage, the outside air supply means is activated and at the same time the throttle valve is appropriately opened to send the outside air into the gas passage for a certain period of time. After a lapse of time, the outside air supply means is stopped and the throttle valve is closed. Thereby, the exhaust gas remaining in the gas flow path, particularly in the solid particle layer is removed, the acid dew point is lowered, and even if the temperature of the solid particle layer is lowered, sulfuric anhydride, water vapor, etc. in the solid particle layer are reduced. No condensation occurs.

Further, when valve means is provided at the fluid inlet and the fluid outlet of the heat transfer tube, at the time of stop, these valve means are closed and the heat transfer tube is made independent from other heated fluid circulation system, It is possible to prevent a sudden temperature drop in the circulation system.

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

As shown in FIG. 1, the fluidized bed heat exchanger according to the present invention has a gas inlet (1a) on the lower side and a gas outlet (1a) on the upper side.
Vertical container (1) with b) and gas inlet (1a) in the container (1)
Horizontally arranged slightly above, a perforated plate (3) formed with a large number of ventilation holes, and sand particles are accumulated in an appropriate thickness on the perforated plate (3) in the container (1). Solid particle layer formed
(4) and have. The top surface of the solid particle layer (4) is in an open state, and a cavity of an appropriate size is formed between the top surface inside the container (1) and the upper end surface of the container (1). There is.

A lead-out pipe (5) is connected to the gas inlet (1a), and the lead-out pipe (5) is further connected to, for example, an exhaust gas emission system of a diesel engine (not shown). A damper (6) for controlling the amount of exhaust gas supplied is provided inside the outlet pipe (5). On the other hand, the gas outlet (1b) is connected to a lead-out pipe (7) internally provided with a damper (8) for controlling the discharge amount of exhaust gas. Thus, from the outlet pipe (5) through the container (1), the outlet pipe
A gas flow path leading to (7) is formed.

Further, a blower (9) is connected to the lower end of the container (1) through a communication pipe (10) so that outside air can be supplied into the container (1). Furthermore, the blower is installed in the communication pipe (10).
A throttle valve (11) is provided for controlling the amount of outside air supplied by (9).

Further, the container (1) is composed of a substantially U-shaped pipe, and a heat transfer tube (12) for transferring water as a heated flow pair has a curved portion.
(12c) is exposed to the outside of the container (1) and two parallel parts (12a), (1
2b) laterally penetrates the container (1), and the parallel portion (12a),
The tip part of (12b) is attached so as to project to the outside of the container (1), and one parallel part (12a) is a solid particle layer (4).
The solid particle layer (4) arranged inside the other parallel part (12b).
Is located above. Then, the one parallel portion (12a)
Has a water intake port (13), and the other parallel part (12b) has a water port (14). Also, the parallel parts (12a), (12
A large number of fins (15), (15) are attached to the outer surface of b) for efficient heat exchange.

The water intake port (13) and the water intake port (14) are respectively provided with valve means (16) and (17) which are electromagnetic valves, and are connected to, for example, hot water or a steam circulation system of a boiler.

Thus, when the heat exchanger is normally operated and the dampers (6) and (8) operate to open the gas flow path, the hot gas flow from the perforated plate (3) into the solid particle layer (4). By the jetting, the solid particle layer (4) is vigorously stirred and heated to be in a fluidized state, and a so-called fluidized bed is formed. At the same time,
The parallel parts (12a), (12b) of the conduction pipe (12) are in contact with this fluidized bed, and the valve means (16), (17) are opened and the water intake (13 Water flowing into the heat transfer tube (12) from () is heated by the fluidized bed and then flows out from the water outlet (14).

On the other hand, when the damper (6) operates so as to close the gas flow passage when the heat exchanger is stopped (at this time, the damper (6)
(8) operates to open the gas flow path. ), At the same time that the blower (9) is operated, the throttle valve (11) is opened to blow the outside air into the container (1). Then, after a certain period of time, the blower (9) is stopped and the throttle valve (11) is closed. As a result, the exhaust gas remaining in the gas flow channel, particularly in the solid particle layer (4) is removed, and the acid dew point of the exhaust gas in the solid particle layer (4) is lowered. Therefore, even if the temperature of the solid particle layer (4) decreases,
No condensation of sulfuric anhydride, water vapor, etc. occurs in (4). In addition, when the heat exchanger is stopped, the valve means (16), (17) are closed, and the heat transfer pipe (12) is separated from the hot water or steam circulation system of the boiler, so that the hot water or steam circulation system of the boiler is Is preferable because the temperature does not drop sharply.

In this example, the communication pipe (10) was connected to the lower end surface of the container (1), but the communication pipe (10) is a perforated plate in the gas flow path.
It may be installed at any position between (3) and the damper (6).

As described above, according to the present invention, the fluidization of the solid particle layer is reliably performed at the time of restarting, and therefore, the operation and the stop can be easily repeated, so that the efficiency of heat exchange is extremely good,
It is possible to provide a practical fluidized bed heat exchanger having a wide range of use.

As described above, according to the present invention, when the gas flow does not pass through the gas passage, such as at the time of stoppage, the outside air is supplied into the gas passage so that the gas passage, especially solid By removing the residual gas in the particle layer, it was made to prevent condensation of anhydrous sulfuric acid, etc. in the solid particle layer, so that the solid particle layer is reliably fluidized by the gas flow at the time of restart, therefore, It is possible to provide a practical fluidized bed heat exchanger that can be repeatedly operated and stopped easily and has a wide range of applications.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the structure of a fluidized bed heat exchanger according to the present invention, and FIG. 2 is a schematic view showing a conventional example. (1) …… Container (3) …… Perforated plate (4) …… Solid particle layer (5) …… Outlet pipe (6) …… Damper (9) …… Outside air supply means (10) …… Communication pipe ( 11) …… Throttle valve (12) …… Heat transfer tube (13) …… Water inlet (14) …… Water outlet (16), (17) …… Valve means

Claims (2)

[Scope of utility model registration request] 1. A gas flow passage that allows gas to pass substantially downwardly from above, a perforated plate disposed so as to block the gas flow passage, and the perforated plate in the gas flow passage. A solid particle layer formed on the top surface of the solid plate which has an open top surface and can be in a fluidized state when a gas passes through; a damper means provided on the upstream side of the perforated plate for controlling the flow rate of the gas; and a fluidized state. And a heat transfer tube which is arranged in the gas flow path so as to be able to contact the solid particle layer in, and whose both end portions project outside the gas flow path and are formed as a fluid intake port and a fluid intake port, respectively. In a fluidized bed heat exchanger having, between the porous plate and the damper means of the gas flow path,
A fluidized bed heat exchanger characterized in that an outside air supply means is connected through a communication passage, and a throttle valve for controlling an air supply amount of the outside air supply means is provided in the communication passage. 2. The fluidized bed heat exchanger according to claim 1, wherein valve means are provided at a fluid intake and a fluid intake of the heat transfer tube.