JPS6347612Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat recovery device for exhaust gas from an internal combustion engine such as a diesel engine.

Generally, exhaust gas from internal combustion engines such as diesel engines has a large amount of thermal energy, and one way to effectively utilize this thermal energy is to
There is a method of recovering thermal energy using a fluidized bed heat exchanger. The fluidized bed heat exchanger used in this method, as shown in FIG. A heat transfer body 5 that circulates water inside to recover the heat of the exhaust gas is connected between them, and exhaust gas pipes 6 and 7 are connected to the lower side and top surface of the box 1, and the box 1 1 is filled with sand (solid particles), and by sending exhaust gas into the box 1 from the exhaust gas pipe 6 on the lower side, the sand in the box 1 is fluidized to form a fluidized bed. This device is designed to efficiently recover the thermal energy of exhaust gas by forming water and circulating water through the heat recovery header 3, heat transfer body 5, and heat recovery header 4.

However, in the fluidized bed heat exchanger configured in this way, if the exhaust gas is sent into the box body 1 without preheating the inside of the box body 1 at the start of internal combustion engine operation, the gas contained in the exhaust gas Water vapor condenses and
There is a problem that a fluidized bed cannot be formed because the sand is stuck. Therefore, conventionally, it has been necessary to provide a hot water boiler, a heater, etc. to warm the sand in the box 1 when the internal combustion engine starts operating, and this has resulted in an extremely high equipment cost.

The present invention provides a
A damper is provided to close the exhaust gas flow path when the internal combustion engine starts operating, and when the exhaust gas flow path is closed by the damper, the damper is installed between the heat recovery flow path and the cooling flow path through which cooling liquid for the internal combustion engine flows. Warming up the fluidized bed heat exchanger by circulating the cooling liquid through the heat recovery channel,
In addition, when a fluidized bed heat exchanger is used, the above-mentioned conventional drawbacks are solved by providing a switching valve that shuts off the flow between the heat recovery flow path and the cooling flow path.
It is an object of the present invention to provide an exhaust gas heat recovery device that does not require equipment for warm-up operation such as a hot water boiler or a heater, and can significantly reduce equipment costs.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, and the reference numeral 10 in the figure is a fluidized bed heat exchanger, whose structure is the same as that of the conventional fluidized bed heat exchanger described above, so a description thereof will be omitted. The heat recovery header 3 on the water inflow side of the fluidized bed heat exchanger 10 is connected to a check valve 12 via an inflow pipe 11.
The check valve 12 is connected to the first switching valve 13 which is a three-way valve via the inlet pipe 18 and the inlet pipe 18.
4 to a water supply header (header) 15. The first switching valve 13 is connected to a hot water header (header) 17 via a pipe 16, and is also connected to a temperature control valve 19 whose flow path is switched depending on the temperature via an inflow pipe 18. There is. Also,
The temperature control valve 19 is connected to an internal combustion engine 21 such as a diesel engine via an inflow pipe 20, and is also connected to the water supply header 15 and the jacket cooling water pump 23 via a pipe 22.
The jacket cooling water pump 23 is connected to the piping 24.
It is connected to the engine 21 via. In addition,
25 is a water supply pump that supplies water to the water supply header 15.

On the other hand, the heat recovery header 4 on the water outflow side of the fluidized bed heat exchanger 10 is connected via a reflux pipe 26 to a second switching valve 27 consisting of a three-way valve.
The switching valve 27 is connected to the hot water header 1 via the piping 28.
7 and is also connected to the jacket cooling water pump 23 via piping 29.

Further, the exhaust outlet 21a of the internal combustion engine 21 is connected to a first damper 31 and a second damper 32 via an exhaust pipe 30. And the first damper 3
1 is connected to a heat exchanger exhaust inlet 6, and similarly, a heat exchanger exhaust outlet 7 is connected to a third damper 33. In addition, the second damper 32 and the third damper 3
3 is connected to an exhaust bypass pipe 34.

Next, the operation of the exhaust gas heat recovery device configured as described above will be explained.

First, after closing the first damper 31 and the third damper 33 and opening the second damper 32 to prevent exhaust gas from passing through the fluidized bed heat exchanger 10, the operation of the internal combustion engine 21 is started, At the same time, the jacket cooling water pump 23 is activated. Then, temperature control valve 1
9 connects the pipes 20 and 22, so the cooling water flows between the jacket cooling water pump 23 and the internal combustion engine 2.
1. The temperature of the cooling water increases as it circulates through the temperature control valve 19. At this time, the water supply pump 25 is not operating, so water in other parts is not flowing. When the cooling water temperature reaches about 85° C., the temperature control valve 19 is switched to connect the inflow pipe 20 and the inflow pipe 18, and the first switching valve 13 is switched to connect the inflow pipe 18 and the inflow pipe 11, Then, the second switching valve 27 is switched to connect the reflux pipe 26 and the reflux pipe 29. As a result, the hot water heated by the internal combustion engine 21 is transferred to the temperature control valve 1.
9. Fluidized bed heat exchanger 10 via first switching valve 13
The water circulates through a flow path that returns from the second switching valve 27 to the jacket cooling water pump 23. This state continues for about 15 minutes to warm up the inside of the fluidized bed heat exchanger 10. At this time, since the check valve 12 is provided, hot water does not flow from the reflux pipe 11 to the pipe 14 side.

After the fluidized bed heat exchanger 10 is warmed up, the second damper 32 is closed, and the first damper 31 and the third damper 33 are closed.
The first switching valve 13 is opened to send the exhaust gas into the fluidized bed heat exchanger 10, and the first switching valve 13 is switched to open the inflow pipe 1.
8 and the pipe 16, and the second switching valve 27
is switched to connect the reflux pipe 26 and the pipe 28. At the same time, when the water supply pump 25 is operated, water is supplied into the fluidized bed heat exchanger 10 via the water supply header 15, piping 14, check valve 12, and piping 11. Therefore, when the exhaust gas generated from the internal combustion engine 21 passes through the fluidized bed heat exchanger 10, its thermal energy is supplied from the water supply pump 25 through the fluidized bed formed within the fluidized bed heat exchanger 10. into the water, increasing the temperature of the water. Then, the water warmed in the fluidized bed heat exchanger 10 flows through the reflux pipe 26,
The water is collected through the second switching valve 27, the piping 28 and the hot water head 17. Further, water supplied from the water supply pump 25 passes through the water supply header 15 and the jacket cooling water pump 23 to cool the inside of the internal combustion engine 21.
After cooling, the water is transferred to the inflow pipe 20 and the temperature control valve 1.
9, the inflow pipe 18, the first switching valve 13, the pipe 16, and the hot water header 17.

In this way, at the start of engine operation, the first, second, and third dampers 31, 32, and 33 are opened and closed to prevent exhaust gas from being sent into the fluidized bed heat exchanger 10, and to prevent internal combustion. The cooling water heated by the engine 21 is circulated to warm the inside of the fluidized bed heat exchanger 10, and after the fluidized bed heat exchanger 10 has sufficiently warmed up, the exhaust gas is sent into the fluidized bed heat exchanger 10, and the exhaust gas is Since the heat energy contained in the engine is recovered, the sand in the fluidized bed heat exchanger 10 will not become stuck due to condensation of water vapor in the exhaust gas when the engine starts operating. In addition, the configuration uses the first and second switching valves 13, 27, the temperature control valve 19, etc. to rationally control the two fluid circuit systems, the engine cooling system and the exhaust gas heat recovery system. There is no need for complicated structures or time-consuming operations to cool the engine or recover heat from exhaust gas.

As explained above, in the present invention, a damper is provided in the exhaust gas flow path to close the exhaust gas flow path for a certain period of time when the internal combustion engine starts operating, and the damper is installed between the heat recovery flow path and the cooling flow path. When the exhaust gas flow path is closed, the cooling liquid after cooling the internal combustion engine is passed through the heat recovery flow path by the engine jacket cooling water pump, and when a fluidized bed heat exchanger is used, the heat recovery flow path is closed. Since the switch valve is installed to cut off the flow between the fluidized bed heat exchanger and the cooling flow path, unlike conventional methods, the sand filled in the fluidized bed heat exchanger is heated at the start of engine operation to reduce the amount of sand contained in the exhaust gas. There is no need to install equipment for warm-up operations such as hot water boilers and heaters, which were used to prevent sand from solidifying due to condensation of water vapor and making it impossible to form a fluidized bed. It has the excellent effect of not only being able to reduce the heat energy but also efficiently recovering the thermal energy contained in the exhaust gas.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional fluidized bed heat exchanger;
FIG. 2 is a piping diagram showing an embodiment of the present invention. 3, 4... Heat recovery header (header), 5...
Heat transfer body, 6... Heat exchanger exhaust inlet, 7... Heat exchanger exhaust outlet, 10... Fluidized bed heat exchanger, 13...
First switching valve, 16...piping, 18...inflow piping,
20... Inflow piping, 22... Piping, 23... Jacket cooling water pump, 24... Piping, 27... Second switching valve, 31... First damper, 33... Third damper.

Claims (1)

[Scope of utility model registration request] A fluidized bed heat exchanger is provided in which a heat recovery flow path for passing a heat recovery liquid is connected to an exhaust gas flow path of an internal combustion engine, and the waste heat of the exhaust gas is recovered by the fluidized bed heat exchanger. In the exhaust gas heat recovery device, a damper is provided in the exhaust gas flow path and closes the exhaust gas flow path for a certain period of time when the internal combustion engine starts operating, and a damper is provided on the inlet side of the fluidized bed heat exchanger in the heat recovery flow path. and an inflow pipe connecting the outlet side of the internal combustion engine in the cooling flow path through which the cooling liquid of the internal combustion engine flows, and when the exhaust gas flow path is closed by the damper, the heat recovery flow path and a first switching valve that communicates with a cooling flow path to allow the cooling liquid after cooling the internal combustion engine to flow through the heat recovery flow path; and an outlet side of the fluidized bed heat exchanger in the heat recovery flow path. and the inlet side of the internal combustion engine in the cooling liquid flow path, and when the exhaust gas flow path is closed by the damper, the piping is communicated with the exhaust gas flow path, and when the fluidized bed heat exchanger is used, the heat recovery is performed. An exhaust gas heat recovery device characterized by being provided with a second switching valve that blocks communication between the flow path and the cooling flow path.