JP3806458B2 - Low pressure steam heating device using heat medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device for heating an object to be heated by steam of a heat medium, and relates to a steam heating device using a heat medium used in various heating processes such as petrochemical industry, synthetic fiber industry, or synthetic resin industry.
[0002]
[Prior art]
As an example of a conventional steam heating apparatus using a heat medium, for example, the one shown in FIG. 2 has been used. This is because the heat medium vapor generated in the heat medium boiler 1 as a heat medium evaporator is supplied to a reaction kettle 2 which is a kind of heat exchanger, and the object to be heated in the reaction kettle 2 is heated. The condensate of the heat medium vapor condensed by heating is caused to flow down to the tank 3 and recovered by the circulation pump 4 to the boiler 1.
[0003]
Various types of heat medium are commercially available and used, but generally have a lower pressure and a higher temperature than steam obtained by boiling normal water, and the heating device has a high pressure resistance design. It can be heated at a relatively high temperature without being used, and is widely used in various heating processes.
[0004]
[Problems to be solved by the invention]
When the conventional steam heating apparatus using a heat medium is used, there is a problem that the heat medium is oxidized and deteriorated by contacting the heat medium with air in the tank. In addition, there is a problem that the odor of the heat medium drifts around because the vaporized heat medium leaks to the outside.
[0005]
Therefore, the technical problem of the present invention is to obtain a low-pressure steam heating apparatus using a heat medium that does not cause deterioration in heat exchange performance due to non-condensable gas.
[0006]
[Means for Solving the Problems]
The technical means of the present invention taken in order to solve the above technical problem is to connect a steam supply pipe of a heat medium to the primary side of the heat exchanger, and convert the heat medium condensed by the heat exchanger to an evaporator or the like. In what is collected at the collection destination, a vacuum pump having an ejector, a tank, and a circulation pump is connected to the secondary side of the heat exchanger, the ejector and the heat exchanger are connected , the tank is sealed , A sub-tank that absorbs the tank internal pressure accompanying the change in the liquid level in the tank is connected to the tank, and a piston is provided inside the sub-tank so as to be movable up and down. of by filling with inert gas, the liquid level in the tank rises, it varies the tank top of the volume by the piston in the sub-tank in response to the change increases, the tank pressure and the piston It is intended to keep substantially equally pressure portion room.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
By connecting an ejector, a tank, and a vacuum pump with a circulation pump on the secondary side of the heat exchanger, and connecting the ejector and the heat exchanger, atmospheric pressure is generated in the heat exchanger by the suction force of the ejector. The low pressure state before and after can be maintained, and the object to be heated can be heated with the low-pressure heat medium vapor.
[0008]
By connecting the sub-tank to the tank, even if the tank is hermetically sealed, the pressure fluctuation accompanying the change in the liquid level in the tank can be absorbed by the sub-tank. Therefore, the heat medium in the sealed tank does not come into contact with air, and the odor of the heat medium does not leak outside.
[0009]
【Example】
An embodiment showing a specific example of the above technical means will be described (see FIG. 1).
In this embodiment, an example in which the reaction kettle 2 is used as a heat exchanger is shown, and the same members as those in the prior art in FIG.
[0010]
The heating medium boiler 1 as an evaporator is connected to the jacket portion 6 of the reaction kettle 2, the lower portion of the jacket portion 6 is connected to the vacuum pump means 7, and the vacuum pump means 7 is connected to the tank 3 and the circulation pump 4. The low-pressure steam heating device using the heat medium is configured by connecting to the heat medium boiler 1.
[0011]
The heating medium boiler 1 and the reaction kettle 2 are connected to each other by a heating steam supply pipe 11 through a pressure regulating valve 8, a gas-liquid separator 9, and a pressure sensor 10. The pressure adjusting valve 8 adjusts the steam pressure in the heating steam supply pipe 11 detected by the pressure sensor 10 to a predetermined value, and the gas-liquid separator 9 is a heat medium in the heating steam supply pipe 11. The vapor and the liquid are separated, and only the separated vapor is supplied to the jacket portion 6 of the reaction kettle 2 and the liquid is discharged from a steam trap 12 provided below the vapor. As the gas-liquid separator 9, a collision type, a centrifugal type, a filter type or the like can be used.
[0012]
The lower connection port 13 of the jacket portion 6 disposed on the outer periphery of the reaction kettle 2 is connected to the ejector 20 of the vacuum pump means 7 through a pipe line 16 provided with a steam trap 14 and a bypass valve 15 in parallel. Further, the outlet of the steam trap 12 of the gas-liquid separator 9 is connected to the ejector 20 via the pipe line 17.
[0013]
The vacuum pump means 7 includes an ejector 20, a tank 21, a circulation pump 22, and a connection pipe line 23. The ejector 20 is formed by a nozzle portion 25 and a diffuser portion 26. A cooling pipe 28 for cooling the heat medium 27 accumulated inside is attached to the tank 21 via a control valve 29, and a temperature sensor 30 for detecting the fluid temperature of the heat medium 27 is attached to the lower part. Although not shown, the temperature sensor 30 and the control valve 29 are connected via a temperature controller so that the temperature of the heat medium 27 can be maintained at a predetermined value.
[0014]
A sub-tank 36 is disposed on the upper portion of the tank 21 via a connection pipe line 31. The sub-tank 36 is provided with a disk-shaped piston 37 that can move up and down to communicate the piston lower chamber 38 with the tank 21. The piston lower chamber 38 and the tank 21 are filled with an inert gas such as nitrogen gas. The upper part of the sub tank 36 is communicated with the atmosphere through the opening 39. A nitrogen gas supply pipe 40 is connected to the lower part of the sub tank 36 via a valve 41.
[0015]
The vacuum pump means 7 circulates the heat medium 27 in the tank 21 through the ejector 20 by the circulation pump 22, generates a suction force at the nozzle portion 25 of the ejector 20, and heats from the jacket portion 6 of the reaction kettle 2. While sucking the medium, the inside of the jacket portion 6 is maintained in a predetermined pressure state.
[0016]
A part of the connecting pipe 23 of the vacuum pump means 7 is branched and connected to the pipe 32 so that a part of the circulating heat medium is supplied from the pipe 33 to the tank 3 and further a pipe 35 is provided. A part of the circulating heat medium is connected and injected into the primary side of the gas-liquid separator 9 in the heating steam supply pipe 11. Even when the heat medium vapor pressure-adjusted by the pressure regulating valve 8 becomes superheated steam through the pipe line 35, a saturation temperature is obtained by injecting a part of the circulating heat medium and exchanging heat in the gas-liquid separation unit 9. It can be steam.
[0017]
Next, the operation will be described.
The heat medium steam generated in the heat medium boiler 1 is pressure-adjusted through the pressure adjusting valve 8 and supplied to the jacket portion 6 of the reaction kettle 2. The jacket portion 6 is in a predetermined low pressure state in advance by the suction force of the ejector 20 of the vacuum pump means 7, and the heat medium vapor supplied to the jacket portion 6 reacts at a predetermined pressure, that is, a vapor temperature. The object to be heated in the pot 2 is heated. The heat medium vapor deprived of heat by heating condenses into a liquid, is sucked into the ejector 20 through the steam trap 14, and reaches the tank 21.
[0018]
The heat medium 27 in the tank 21 is cooled to a predetermined temperature by the cooling pipe 28, supplied to the ejector 20 by the circulation pump 22, and sucks the heat medium in the jacket portion 6 again. Since the suction force generated by the ejector 20 is determined by the temperature of the fluid passing through the ejector 20, the suction force of the ejector 20, that is, the degree of pressure reduction, is adjusted by appropriately adjusting the temperature of the heat medium 27 in the tank 21. Can be controlled. By controlling the suction force of the ejector 20, the pressure state in the jacket portion 6 can be controlled, and the pressure in the jacket portion 6 can be controlled from a negative pressure state below atmospheric pressure to a positive pressure state above atmospheric pressure. Can be controlled.
[0019]
When the liquid level of the heat medium 27 in the tank 21 rises, the volume of the upper part of the tank 21 changes, and the piston 37 in the sub-tank 36 rises in accordance with the change, whereby the pressure in the tank 21 and the piston lower chamber 38 are increased. Keep the pressure at almost the same. Since the piston lower chamber 38 and the upper portion of the tank 21 are filled with an inert gas such as nitrogen gas, the heat medium 27 does not come into contact with air.
[0020]
For example, if a product with the product name Dowsome is used as the heat medium, the steam temperature will be about 210 degrees C if the steam pressure is 0.3 kg in absolute pressure, and about 260 degrees C if the steam pressure is 1.1 kg The steam temperature can be controlled by controlling the steam pressure.
[0021]
In the present embodiment, an example in which the reaction kettle 2 is used as a heat exchanger has been shown. However, the heat exchanger is also used as another heat exchanger, for example, a synthetic fiber or a synthetic resin, or a heat exchanger such as a food product or a medical product. It is something that can be done.
[0022]
【The invention's effect】
As described above, according to the present invention, the sub-tank is provided and the tank is hermetically sealed, so that the heat medium can be prevented from coming into contact with air, and the deterioration due to oxidation of the heat medium can be prevented. A low-pressure steam heating apparatus using a heat medium that can prevent the odor of the heat medium from drifting can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a low-pressure steam heating apparatus using a heat medium according to the present invention.
FIG. 2 is a configuration diagram showing a conventional steam heating apparatus using a heat medium.
[Explanation of symbols]
1 Heating medium boiler
2 Reaction kettle 6 Jacket part 7 Vacuum pump means 20 Ejector
21 Tank 22 Circulating pump 31 Connection pipe line 36 Sub tank 37 Piston 38 Piston lower chamber

Claims (1)

A heat supply steam supply pipe is connected to the primary side of the heat exchanger, and the heat medium condensed by the heat exchanger is recovered at a recovery destination such as an evaporator. An ejector and a tank are connected to the secondary side of the heat exchanger. Connect a vacuum pump with a circulation pump, connect the ejector and the heat exchanger, make the tank hermetically sealed, and connect a sub-tank that absorbs the tank internal pressure accompanying changes in the liquid level in the tank to the tank. When the liquid level in the tank rises by providing a piston movably up and down inside the sub tank and filling the lower chamber of the piston and the tank with an inert gas such as nitrogen gas , change the upper portion of the volume by the piston in the sub-tank in response to the change increases, the low pressure due to the heat medium, characterized in that to maintain the pressure in the tank pressure and the piston lower chamber almost equal Gas-heating device.

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