JP2568967Y2 - Exhaust gas heat exchanger - Google Patents

Description

[Detailed description of the invention]

[0001]

[Industrial application field] The present invention relates to a diesel engine
It relates to the structure of a heat exchanger for cogeneration.

[0002]

2. Description of the Related Art A cogeneration system that collects and simultaneously uses waste heat exhausted from a prime mover such as a diesel engine, a gas engine, a gas turbine, etc., is capable of improving overall efficiency. Widely used in industrial facilities. However, since the load factor (operating condition) of a prime mover such as an engine changes with the increase or decrease in electricity demand, the exhaust gas temperature changes depending on the load condition. In addition, there is a problem that corrosion on the heat transfer surface of the heat exchanger occurs due to dew condensation of the exhaust gas, thereby shortening the life of the heat exchanger.

[0003]

SUMMARY OF THE INVENTION In the present invention, in a heat exchanger for cogeneration such as a diesel engine, a heat transfer surface or a heat exchange load amount in the heat exchanger is changed according to a change in engine load. It is an object of the present invention to reduce the dew condensation on the heat transfer surface in the heat exchanger to extend the life of the heat exchanger and improve the heat exchange efficiency.

[0004]

In the present invention SUMMARY OF THE INVENTION, in accordance with the load of the engine in order to solve the problems above problems, by varying the heat transfer surface product of the heat exchanger, condensation of flue gas in the heat transfer surface To prevent. Therefore, in the heat exchanger, provided with a plurality of partition parallel to the flow of the exhaust gas, heat
Divide the inside of the exchanger into a plurality of parallel stacks,
Re installing a heat exchange unit. Water supply to heat exchange section and exhaust gas
Is introduced by opening and closing the water supply on-off valve and damper.
Opening and closing are performed for each heat exchange unit . Opening / closing of the water supply on-off valve and damper is controlled by a control device that takes in the load signal from the engine or the signal of the exhaust gas temperature from the engine , and when the load is low or the exhaust gas temperature is low,
Reduced number of heat exchange units for water supply and exhaust gas introduction
Let

[0005]

[Effect] With the fluctuation of the engine load, the exhaust gas amount becomes
Fluctuates and the load decreases, reducing the amount of exhaust gas.
Then, the exhaust gas temperature and the exhaust gas flow rate decrease. Guiding exhaust gas
Restricting the heat exchange section that enters, the cross-sectional area of the flue of the heat exchange section
Exhaust gas flow rate increases because but it decreases, to decrease the heat transfer area
The Rukoto significant temperature drop in the heat transfer surfaces is prevented by that, can reduce condensation of the exhaust gas, it is possible to further reduce the deposition of soot.

[0006]

An embodiment of the present invention will be described with reference to FIGS. In this case, the case where the flue portion of the exhaust gas of the heat exchanger is divided into four sections will be described. The heat exchanger body (3) is divided into four parts by a partition plate (2), and each part is provided with a heat exchange part (1) to form four flues . A plate-shaped damper (4) is provided for each partition plate on the exhaust gas introduction portion side, and the damper is rotated by a damper driving device (10) to guide the exhaust gas.
The number of chimneys to enter can be adjusted . The piping connected to the heat exchange section is provided with a water supply on-off valve (6) on the water supply inlet side and a check valve (5) on the water supply outlet side. However,
If all the damper (4) is closed, the water supply opening closed in pipe connected to the heat exchange section of a portion the exhaust gas is lead (1) is not required.

The water supply on-off valve ( 6 ) and the damper driving device (10) are electrically connected to the control device (9).
It is driven by a signal from the control device (9). A load signal from the engine or a signal of exhaust gas temperature or the like is input to the control device. The control device has a predetermined setting control signal.
Has become a value to be set, the control device damper
-If there are three sets of devices, set the values of the three setting control signals.
Set. Control unit is engine load or exhaust gas temperature
By comparing the set control signals at three points,
Calculate one of the control signals
Damper control signal to open and close the damper
Output to the par drive.

The relationship between the damper control signal and the operation of the damper (4) and the water supply on-off valve (6) is as follows. Damper (4) open physician by the damper drive (10)
When the damper (4) is opened, the water supply opening / closing valve (6) installed in the pipe leading to the heat exchange part where the exhaust gas passes also opens. That is, the damper driving device (1)
The signal to 0) and the associated signal to the water supply on-off valve (6) are linked. An embodiment of the control of the damper and the water supply on-off valve will be described with reference to FIGS. The 1,2,3 damper in FIGS. 3 and 4, the damper 1 damper is shown in FIG. 1 from the left of the drawing, the damper 2, the damper 3
The corresponding water supply on-off valves are supplied.
The water on-off valve 1, the water supply on-off valve 2, and the water supply on-off valve 3 are assumed. control
The setting control signal 1, setting control signal 2, setting control signal
No. 3 is set and the engine load or exhaust gas
Temperature value, setting control signal 1, setting control signal 2, setting control signal
Compare the value of control signal 3 to determine whether the engine load or
If the control temperature is lower than the value of the set control signal 1,
No. 1 is calculated, and the setting control signal 1 or more and the setting control signal 2
In this case, the control signal 2 is calculated and the setting control signal 2 or more is set.
If less than control signal 3, control signal 3 is calculated and set control signal
If the number is 3 or more, the control signal 4 is calculated, and the calculated 1
Based on the control signals (1) to (4), as shown in FIG.
And controls the water supply on-off valve. The control device controls the calculated control.
The damper and the water supply on-off valve are opened and closed by a signal.
Exhaust when engine load or exhaust gas temperature is low.
Reduce the number of flues for gas flow and reduce engine load
Or a flue through which the exhaust gas flows when the exhaust gas temperature is high
Increase the number of. When engine load is low, exhaust gas temperature
And the flow rate of exhaust gas decreases,
Reducing the number of flues to be introduced reduces the cross-sectional area of the flue.
The flow rate of the exhaust gas rises and soot becomes less likely to adhere
The temperature of the exhaust gas is too low in the heat exchange section, resulting in condensation.
No more.

[0009]

[Effects of the Invention] By implementing the present invention, the dew condensation of corrosive gas at the time of low load of the engine is reduced, so that the adhesion of soot can be reduced, the life of the heat exchanger is extended , and heat exchange is performed.
A decrease in efficiency can be prevented .

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of an AA cross section in FIG. 1;

FIG. 3 is an explanatory view of opening and closing of a control signal, a damper, and a water supply on-off valve

FIG. 4 shows a relationship between a setting control signal and a control signal.

[Description of Signs] 1 Heat exchange unit 2 Partition plate 3 Heat exchanger body 4 Damper 5 Check valve 6 Water supply on-off valve 7 Exhaust gas inlet 8 Exhaust gas outlet 9 Control device 10 Damper driving device

Claims (1)

(57) [Scope of request for utility model registration] 1. A flue portion of a main body through which exhaust gas passes is divided into two or several flues by providing a partition plate, and a heat exchanging portion composed of a heat transfer tube and a fin is provided in the divided flue portion. A water supply opening / closing valve is provided on the inlet side pipe for supplying water to the heat exchange section, and an outlet side for taking out water supplied to the heat exchanger.
Pipe a check valve provided on, provided divided into branch portions of the smoke path unit da <br/> bumpers and dampers driving apparatus respectively, the water supply on-off valve and the exhaust gas heat exchanger the control device is connected to opening and closing control a damper .