JPS6218879Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is a heat pipe that is used as a means of heat exchange between low temperature gas and high temperature gas used for exhaust gas treatment, or heat exchange between liquid and gas in chemical plants. The present invention relates to a heat exchanger having a heat pipe, and more particularly to a heat exchanger that allows steel grains to be shot or poured onto a heat pipe to effectively clean the fins.

[Prior Art] Wet flue gas desulfurization equipment is usually installed in commercial boilers of power plants, steel mills, private boilers, and other combustion equipment, but the exhaust gas from this equipment is saturated with water, so Due to poor diffusion, chimneys are corroded and white smoke is produced. Therefore, a gas-gas indirect heat exchanger is used to reheat the exhaust gas at the outlet of the wet flue gas desulfurization equipment, but as a heat exchanger in this case or as a heat exchanger for other exhaust gases, The use of heat pipes, particularly heat pipes with fins, has been proposed and put into practical use. When a heat pipe with fins is used in a heat exchanger, the problem is that dust, gaseous substances, mist, etc. in the exhaust gas adhere to the fins, impairing the heat transfer effect, and growing. The gap becomes clogged and becomes unusable.

Conventionally, a soot blower was installed to prevent this.
As shown in Fig. 1, the nozzle 1 is drawn into the heat exchange chamber, and a plurality of the nozzles are arranged so as to face a plurality of heat pipes 2 with fins. Removes dirt such as dust and mist.

[Problems to be solved by the invention] However, this conventional method has the following drawbacks.

Power costs are high because large amounts of high-pressure steam and compressed air are required.

The greater the distance between the nozzle and the object, the worse the cleaning effect.

In particular, finned heat pipes with a larger number of fins, which serve as heat transfer surfaces, have a poor cleaning effect and cannot prevent clogging, so periodic cleaning with water is required.

One possible way to solve this problem is to spray solids such as steel particles instead of fluid.
In the case of a large heat exchanger, if you try to clean the entire surface of the finned heat pipe at once, a large amount of steel particles will be required, and if a large amount of input or shot hits the finned heat pipe at once, the finned heat pipe will It is expected that pipe wear will occur.

Therefore, the inventors of the present invention have devised the present invention in order to effectively solve the above-mentioned problems when a cleaning means using steel particles is adopted, and also to eliminate the above-mentioned conventional drawbacks.

Therefore, the purpose of the present invention is to allow a small group of steel grains to partially hit the heat pipe so that the deposits can be reliably removed without damaging the heat pipe, and at the same time, it is possible to remove the deposits without damaging the heat pipe. An object of the present invention is to provide a heat exchanger that can reduce the power required.

[Means for Solving the Problems] The heat exchanger of the present invention is a heat exchanger using exhaust gas in which a heat pipe is arranged in a heat exchange chamber, and the heat exchanger is cleaned by introducing steel particles. , the heat exchange chamber is divided into small compartments in which the heat pipes are distributed by a permeable screen that allows the passage of exhaust gas and dust but restricts the passage of the steel grains; Separate input ports are provided, and opening/closing valves are interposed to control the input of steel grains by sequentially opening each input port to input steel grains in small sections.

[Operation] First, when the opening/closing valve of the input port provided in the first small section is opened, steel grains are introduced from the input port to clean the heat pipe in the first small section.
Next, the on-off valve is closed, and
The opening/closing valve of the input port of the second sub-section is opened, and the steel grains are input and cleaned. In this way, the heat pipes in each subdivision are sequentially and individually cleaned.

Since the heat exchange chamber is divided by a ventilation screen, the steel grains introduced into one compartment will not enter the other compartments, and therefore a small amount of steel grains will be used to fill the corresponding compartment. It goes all over the heat pipe inside.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, reference numeral 3 designates one heat exchanger forming a gas-gas indirect heat exchanger 4 consisting of a high temperature side heat exchanger and a low temperature side heat exchanger. This heat exchanger 3
In this case, six groups of heat pipes with fins are arranged in multiple stages in the heat exchange chamber 3a and extend horizontally to the adjacent heat exchanger 5, and the fins serve as a heat transfer surface. The heat exchanger is configured to transfer heat from a fluid passing through one heat exchanger to a fluid passing through another heat exchanger. Reference numeral 7 denotes a ventilation screen, which extends along the longitudinal direction of the 6 groups of finned heat pipes at predetermined intervals and along the weight direction, thereby dividing the heat exchanger 3a into small sections. , the divided small sections are used as passages 8. The permeable screen 7 has a mesh shape that allows exhaust gas and dust to pass through, but prevents steel grains, which will be described later, from passing through.

Above each passage 8, an input port 9 for steel grains is provided which communicates with the passage, and the base ends are connected to a single hopper 11 via an opening/closing valve 10 in the middle.
is connected to. The on-off valves 10 are not all opened at the same time, but only one is controlled to open sequentially according to a time schedule, and a predetermined amount of steel grains is supplied from the hopper 11 only to the passage 8 communicating with the opened on-off valve 10. is configured to be input.

As shown in FIG. 3, the steel grains 12 are heavy enough to fall under their own weight, and have a grain size that allows them to pass through the gaps between the fins of the finned heat pipe 6.

A return path 13 connecting the bottom opening of the heat exchange chamber and the hopper 11 is formed outside the heat exchange chamber 3a. This return path 13 is the exhaust collection and separation system 1
4, a vertical conveyor 15, and a conveyance system 16,
The waste collection and separation system 14 collects the waste containing the steel grains 12 that have flowed through the passage 8 and fallen and accumulated at the bottom opening, and from this, only the steel grains are separated, and the steel grains are lifted and conveyed by the vertical conveyor 15. It is configured to return to the hopper 11 via the system 16.

The operation of the present heat exchanger having the above configuration will be described.

A small amount of steel grains 12 sufficient to clean the inside of one passage is stored in the hopper 11, and the first on-off valve 10 is opened. As a result of this opening, the steel grains 12 roll down due to the slope of the input port 9 and flow down through the opening into the passage 8 communicating therewith. During this flow, the steel grains 12 collide with or come into contact with the outer circumferential surface of the fins, etc. of the finned heat pipe 6 that intersects with the passage 8, and scrape off the dust adhering thereto. Also heat exchange room 3
Dust on the inner wall surface of a is also removed in the same way. Since the passage 8 is partitioned by a breathable screen 7, the steel grains 12 do not enter other passages 8, and the steel grains 12 flow uniformly from top to bottom due to their own weight. It will reach you without any trouble. Therefore, the dust inside this passage 8 can be completely removed.

Next, the small amount of recovered and separated steel grains 12 is returned to the hopper 11 via the return path 13, and then
By opening the second on-off valve 10, the next passage is cleaned. In this way, cleaning is performed sequentially for each passage 8. In this specific embodiment, for example, as shown in FIG. 4, the heat exchange chamber 3a is vertically divided into eight small sections A to H by a ventilation screen 7 indicated by dotted lines, and predetermined Steel grains are added sequentially according to the time schedule,
It is conceivable that the steel grains for one section are repeatedly used.

On the other hand, in order for the heat exchanger to perform its original function, it is required that the exhaust gas uniformly pass through the heat exchange chamber 8, but the ventilation screen 7 does not support the passage of the exhaust gas a at all. Therefore, the third
It is also possible to hang the screen 7 perpendicularly to the inflow direction of the exhaust gas as shown in FIG.

Therefore, unlike the method in which a large amount of steel grains 12 is introduced and dropped over the entire cross section of the heat exchange chamber 3a at once, the steel grains 12 are introduced only into one partitioned passage, so only a small amount can be introduced at one time. Moreover, since this amount is sufficient to clean the finned heat pipe 6 in the passage, complete cleaning can be achieved.

In addition, since only a small amount of steel grains hit the finned heat pipe 6, it is possible to avoid applying excessive impact force to the finned heat pipe, so it is possible to extend the life of the finned heat pipe. .

In addition, by setting the amount of steel grains 12 to be introduced at one time for only 8 minutes per passage due to the time schedule, when recovering the steel grains, the energy for transporting the steel grains is sufficient for that small amount, so it is possible to reduce power costs. .

In the above embodiment, the steel grains 12 are injected from above into the heat exchange chamber 3a, but the same effect can be obtained even if the steel grains 12 are injected from the side as shot grains.

[Effects of the invention] In summary, the present invention provides the following excellent effects.

(1) It is possible to completely remove dust from a heat exchanger with a small amount of steel particles, increasing efficiency and making the heat exchanger more compact, while also making it possible to clean large heat exchangers.

(2) Since a large amount of steel grains do not hit the heat pipe at once, it is possible to reduce wear and tear on the heat pipe and extend its life.

(3) Since the amount of steel grains used at one time is small, the power energy needed to transport and input them can be reduced, resulting in resource and energy savings.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating a conventional method for cleaning a heat exchanger, Fig. 2 is a schematic front view showing a preferred embodiment of the heat exchanger according to the present invention, and Fig. 3 is a schematic diagram showing one passage of the same. FIG. 4 is a schematic plan view showing a modification of the same as the above. In the figure, 3 is a heat exchanger, 3a is a heat exchange chamber, 6 is a heat pipe with fins showing an example of a heat pipe, and 7 is a heat exchanger.
8 is a ventilation screen, 8 is a passage, 9 is an inlet for steel grains, 10 is an on-off valve, 11 is a hopper, 12 is a steel grain, 13 is a return path, and a is an exhaust gas.

Claims (1)

[Scope of utility model registration request] In a heat exchanger that uses exhaust gas and has a heat pipe arranged in the heat exchange chamber and is cleaned by introducing steel grains, the passage of exhaust gas and dust is allowed, but the passage of the steel grains is restricted. The heat exchange chamber is divided into small sections so that the heat pipes are distributed by a ventilation screen, each of which is provided with an inlet for steel grains, and each inlet is injected with steel grains in small sections. 1. A heat exchanger characterized in that an opening/closing valve is provided to control the injection of steel grains by sequentially opening and closing the valves to control the injection of steel grains.