JPS5833478B2 - Method and equipment for purifying shell-and-tube heat exchangers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for purifying the inside of a shell-and-tube heat exchanger in which primary and secondary fluids flow inside and outside a large number of heat exchanger tubes to perform mutual heat exchange. It is something.

In recent years, in view of the need for energy conservation, plans are being advanced for the use of heat from high-temperature waste gas or geothermal water in the steel industry, process industry, etc.; In many cases, it contains a large amount of various impurities, so dust and scale adhere to the heat transfer surface of the heat exchanger, resulting in a decline in heat transfer performance due to dirt.

Conventionally, soot blowing using steam or the like is used to solve this problem, but it is difficult to remove parts that are far from the blow nozzle or the back side of the heat exchanger tubes, and it is especially difficult to completely remove sticky scale. Ta.

Such adhesion of dust and scale not only deteriorates heat transfer performance but also accelerates corrosion of heat transfer tubes depending on the substance, and has been one of the biggest causes of impeding the promotion of the above-mentioned waste heat utilization.

The present invention eliminates the above-mentioned drawbacks of the conventional system by filling and retaining a certain amount of solid particles such as sand or metal balls in the jacket of such a shell-and-tube heat exchanger, and rotating the jacket horizontally. A cleaning method for a shell-and-tube heat exchanger that can completely remove dirt on the outside of heat transfer tubes by using a cleaning effect based on the tumpling action of particles, reliably remove dirt on the heat transfer tubes, and eliminate obstacles when utilizing waste heat, and the method thereof. The purpose is to provide a device.

The present invention provides a multi-tubular heat exchanger consisting of a large number of heat exchanger tubes, end chambers connected to both ends of the heat exchanger tubes, and a rotating jacket surrounding the heat exchanger tubes, in which abrasive solid particles such as sand or metal balls are placed inside the jacket. The heat exchanger tube, the end chamber, and the jacket are integrated with each other by a timer, or the temperature difference between the inside of the heat exchanger tube or the part connected to it and the outside or the part connected to it is detected. The abrasive solid particles are intermittently rotated horizontally to cause the abrasive solid particles to slide down and transfer between the heat transfer tubes located in the space, and the heat transfer tubes are passed through the moving abrasive solids to remove dirt on the outside of the heat transfer tubes. A method and apparatus for purifying a shell-and-tube heat exchanger, characterized by removing

The present invention will be explained with reference to the drawings based on examples.

Figures 1 and 2 show an example of heat exchange between high-temperature contaminated waste gas and air (or water), in which a large number of heat exchanger tubes 1 are attached at both ends to tube sheets 23 and 23'. , the tube plate 23
.
24' has an inner cylinder 6. arranged concentrically with respect to the horizontal axis center ■-■. σ and outer cylinders 5, 5' are attached.

The inner cylinder 6°6' and the outer cylinders 5, 5' rotate together with the jacket 3 to form a rotating double cylinder.

On the other hand, an inner cylinder 8° 8' and an outer cylinder 7, 7' forming a fixed double cylinder are provided above the horizontal axis center ■-■.
Inner cylinder 6 and 8.6', outer cylinder 5 and 7.5' and 7
' are rotatably and airtightly connected to each other via seals 10, 10' and 9,9'.

That is, the rotating double cylinder and the stationary double cylinder form an airtight rotary joint for two systems of fluid via a seal.

Tires 11 and 11' are provided in the end chambers 2 and 2', respectively, and are installed on rollers 12 and 12', and the main body is rotated by a drive device 13 in the direction of arrow R around the horizontal axis ■-■. It looks like this.

As shown in FIG. 2, a suitable amount of sand 14 of a suitable particle size is held in the inner chamber 4 of the mantle 3 as abrasive solid particles.

The grain size of the sand 14 is selected so that it will not be scattered by the flow velocity of the high temperature waste gas 16 passing through the baffle 15 fixed in the inner chamber 4, and the amount of sand filled is determined so that each heat exchanger tube 1 is The amount is selected so that it can come into contact with sand and not flow out of the inner chamber 4.

In order to prevent the sand 14 from escaping and flowing out, it is more effective to provide a perforated plate 17 or a net at the outlet of the inner chamber 4 leading to the inner cylinder 6' on the downstream side.

In this case, the pore diameter of the perforated plate 17 does not necessarily need to be smaller than the grain diameter of the sand.

In the figure, 18 is the inlet for high temperature waste gas, 19 is the same outlet, 20 is the air (or water) inlet, and 21 is the same outlet, which serves as a fluid supply and discharge port. Enters the inner chamber 4, enters from 20 here, passes through the end chamber γ, and enters the heat exchanger tube 1.
The air (or water) that has entered is heated and discharged from the outlet 19, and the heated air (or water) is discharged from the outlet 21 via the end chamber 2.

A time interval in which dirt accumulates on the outer surface of the heat exchanger tube 1 and becomes a substantial obstacle, and a time interval in which dirt can be removed and restored are set in advance in a timer, and the driving device 13 is activated by an automatic command from the timer. Make it stop.

Due to the rotational movement of the mantle, the sand is tampled as shown in Figure 2, and the dust and scale on the outside of the heat transfer tube is peeled off and finely divided by the cleaning effect based on mutual collision and friction between the sand and the heat transfer tube, and fine particles are removed. It is discharged from the outlet 19 along with the waste gas, and is further passed through a dust collector 2 such as a cyclone.
The dust is captured and collected by 2.

Another method of cleaning operation is to use the heat exchanger inlet/outlet 1B, 1
9, 20, and 21 may be provided, respectively, and the reduction and restoration values of the average temperature difference based on the contamination of the heat exchanger tubes may be set, and the drive device 13 may be started and stopped in accordance with the commands.

The above explained the case of heat exchange between high-temperature contaminated waste gas and air (or water), but heat exchange between contaminated hot water containing silt and various metal salts and clean water, such as when using geothermal water, is also explained. is the same as above.

In this case, due to the specific gravity and viscosity of the thermal fluid, the abrasive solid particles filled in the mantle have a particle size of approximately several millimeters and are made of metal balls such as stainless steel.

Contaminated hot water and fresh water enter from 18.20, respectively, and reach 19°21.
The scales such as silt and precipitated metal salts that are discharged from the heat exchanger tube 1 and adhere to the outside of the heat exchanger tube 1 are peeled off and finely disposed of by the mutual collision and friction between the metal sphere and the heat exchanger tube due to the rotational movement of the jacket, and are converted into waste heat. It is discharged along with the water.

On the other hand, by selecting the mesh of the perforated plate 17 to be smaller than the diameter of the metal ball, the metal ball can be completely prevented from flowing out of the inner chamber 4.

The present invention makes it possible to prevent dust and scale from adhering to the heat transfer surface during heat exchange between high-temperature waste gas, hot water, etc. containing a large amount of various impurities, and air or water, thereby improving heat transfer performance. Purification of shell-and-tube heat exchangers makes it possible to utilize waste heat in areas that are practically difficult to use with conventional technology, as it can prevent the decrease in heat exchanger temperature and, in some cases, also help prevent corrosion of heat exchanger tubes. A method and apparatus thereof can be provided,
Moreover, power saving can be achieved by removing scale as needed or intermittently at regular intervals, which is extremely effective in terms of energy saving in practice.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, with FIG. 1 being a longitudinal sectional view and FIG.
The figure is a cross-sectional view taken along the line XX in FIG. 1. 1... Heat exchanger tube, 2, 2'... End chamber, 3
...Cloak, 4...Inner chamber, 5,5'...
...outer cylinder, 6. Gi・・・Inner cylinder, 7,
7'...Outer cylinder, 8,8'...Inner cylinder, 9.9'...Seal, 10.10'...
... Seal, 11, 11' ... Tire,
12.12'...Roller, 13...Drive device, 14...Sand, 15...Baffle, 16...High temperature waste gas , 17... Perforated plate, 18... High temperature waste gas inlet, 19...
...High temperature waste gas outlet, 20... Air (or water)
Inlet, 21...Air (or water) outlet, 22
...Dust collector, 23゜23'...Tube plate, 24,24'...End plate.

Claims (1)

[Scope of Claims] 1. In a multi-tube heat exchanger consisting of a large number of electric heating tubes, end chambers connected to both ends of the heat exchanger tubes, and a rotating jacket surrounding the heat exchanger tubes, sand or metal balls or the like are placed inside the jacket. A certain amount of abrasive solid particles are filled and held while leaving a certain amount of space, and the heat exchanger tube, the end chamber, and the outer mantle are integrated with each other by a timer, or the temperature of the inside of the heat exchanger tube or the part connected to it and the outside or the part connected to it is controlled. By detecting the difference, the abrasive solid particles are intermittently rotated horizontally to slide down and transfer between the heat transfer tubes located in the space, and the heat transfer tubes are passed through the moving abrasive solid to the outside of the heat transfer tubes. A method for purifying a shell-and-tube heat exchanger, characterized by removing dirt from it. 2. In a multi-tubular heat exchanger consisting of a large number of heat transfer tubes arranged between tube sheets, end chambers sectioned and connected to both ends of the heat transfer tubes via tube sheets, and a rotating jacket surrounding the heat transfer tubes, the rotating jacket A rotating double cylinder in which abrasive solid particles such as sand or metal balls are accommodated with a space left in the inner chamber including a group of heat transfer tubes, and the outer mantle inner space and the end inner space are centered around a horizontal rotation axis. and a fixed double cylinder, the outer cylinder and the inner cylinder of the art heavy cylinder are relatively rotatable and arranged in airtight contact with each other, and the inner cylinder of the rotating double cylinder is connected to the inner chamber. The outer cylinder of the rotating double cylinder is connected to a fixed inner cylinder and communicated with a high-temperature waste gas flow path, and the outer cylinder of the rotating double cylinder is connected to a separate fluid supply and drainage path provided outside via a rotary joint attached to the end plate of the end chamber. The heat exchanger tube, the end chamber, and the jacket are connected to each other in an airtight manner, and the heat exchanger tube, the end chamber, and the jacket are rotatably supported as an integral structure around a horizontal axis, and a timer or A purification device for a multi-tube heat exchanger, characterized by comprising a detector that detects and commands a temperature difference between the inside of the heat exchanger tube or a portion connected thereto and the outside or a portion connected thereto.