JP2000271403A - Reboiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure heat flux required for a stable boiling state without increasing a holdup and to prevent the lowering of electrical insulating property and heat insulating performance encountered when vacuum heat insulation structure is adopted in a reboiler constructed so that the holdup in the reboiler vessel is heated by an electric heater. SOLUTION: Plural immersion heaters 6 immersed in a holdup in a reboiler vessel are provided side by side in the horizontal direction, erected on a bottom surface 5a of the reboiler vessel 5, and the required heat quantity is dealt with by the number of the installed electric heaters, thereby limiting the heat flux by each electric heater to the extent required for stable boiling and also limiting the size of the electric heaters so that the holdup is not increased more than required. And terminal parts 13 of the immersion heaters 6 pulled out to outside the reboiler vessel are housed in a vacuum heat insulating vessel to prevent dew condensation of the terminal parts and heat entered from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reboiler in which a liquid retained in a reboiler container is heated by an electric heater.

[0002]

2. Description of the Related Art In low-temperature distillation in which a distillation operation is carried out at a temperature lower than ordinary temperature, a reboiler is employed which heats and evaporates a retained liquid in a reboiler vessel by a casting or casting type electric heater. In addition, a structure in which a reboiler is housed in a vacuum insulated container is often employed to ensure high heat insulation.

[0003]

However, in the configuration in which the cast-in heater is mounted on the outer wall surface of the reboiler vessel, heat is transferred at the contact surface between the heater and the reboiler vessel, so that the heat flux required for a stable boiling state is obtained. If an attempt is made to increase the heat transfer area in order to secure a sufficient size, the size of the reboiler container will increase, leading to an increase in the liquid holding capacity. This causes an increase in the concentration time and causes a decrease in the distillation rate. Particularly, when the scale of the apparatus is increased due to an increase in the liquid holding amount relative to the surface area of the reboiler as the size of the reboiler is increased. Is remarkable.

In the structure in which the reboiler is housed in the vacuum insulated container, the terminal of the electric heater is arranged outside the vacuum insulated container in consideration of maintenance, but the surrounding air is affected by the low-temperature liquid in the reboiler container. As a result, dew condensation occurs at the terminal portion, resulting in a decrease in electrical insulation. In addition, heat input from around the terminals of the electric heater exposed outside the vacuum heat insulating container deteriorates the heat insulating performance.

Furthermore, when a cast-in heater is employed in a structure in which a reboiler is housed in a vacuum insulated container, since the area around the heater is in a vacuum state, the contact surfaces of the heater and the reboiler container are not microscopically smooth, so that a partial area is required. The heat transfer efficiency depends on the heat transfer between the solids and the radiant heat transfer due to the contact.

The present invention has been devised to solve the problems of the prior art in a reboiler configured to heat the liquid retained in a reboiler container by using such an electric heater. First, it is possible to secure the heat flux required for a stable boiling state without increasing the liquid holding amount, and second, it is possible to avoid a decrease in the electrical insulation and the heat insulation performance caused when a vacuum heat insulation structure is adopted. What can be done, third
Another object is to prevent a decrease in heat transfer efficiency caused when a cast-in heater is employed in a vacuum heat insulating structure.

[0007]

In order to achieve the above object, according to the present invention, in a reboiler configured to heat a liquid retained in a reboiler vessel by an electric heater, the electric heater is provided inside the reboiler vessel. Immersion heater immersed in the stagnant liquid, and a plurality of heaters are provided side by side on the bottom surface of the reboiler container.

[0008] According to this, the required amount of heat is controlled by the number of electric heaters installed, so that the heat flux by each electric heater is limited to a level necessary for stable boiling, and the liquid holding amount is increased more than necessary. The size of the electric heater can be limited so as not to cause this. As a result, a heat flux required for a stable boiling state can be secured, and at the same time, an increase in the liquid holding amount can be avoided, and the concentration time can be shortened to improve the distillation performance.

Further, in the present invention, in a reboiler housed in a vacuum insulated container for enhancing heat insulation in low-temperature distillation and heating a liquid retained in the reboiler container by an electric heater, the electric heater comprises: It is a throw-in heater immersed in the staying liquid in the reboiler container, and a terminal portion of the electric heater drawn out of the reboiler container is accommodated in the vacuum heat insulating container.

According to this, it is possible to avoid a decrease in electrical insulation and a decrease in heat insulation performance due to dew condensation that occurs when the terminal portion of the heater is disposed outside the vacuum insulation container.

Further, in the present invention, it is housed in a vacuum insulated container for enhancing heat insulation in low-temperature distillation,
In a reboiler configured to heat a liquid retained in a reboiler container by an electric heater, the electric heater is a cast heater mounted on an outer surface of the reboiler container, and the periphery of the electric heater is a vacuum in the vacuum heat insulating container. The partition was provided so as to be isolated from the part, and nitrogen was sealed inside the partition.

According to this, if a partition is provided so that at least the contact heat transfer portion between the electric heater and the reboiler vessel is covered with the nitrogen-filled layer, the minute gap between the electric heater and the reboiler vessel is filled. Nitrogen acts as a heat transfer medium, so that a decrease in heat transfer efficiency can be avoided. further,
If a partition is provided so that the terminal portion of the electric heater is also covered with the nitrogen-filled layer, a decrease in electrical insulation can be avoided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of a reboiler according to the present invention, and FIG. 2 shows a reboiler 1 shown in FIG.
1 shows a schematic configuration of the entire distillation apparatus to which is applied. The distillation apparatus shown in FIG. 2 performs a distillation operation under a temperature condition equal to or lower than room temperature, and condenses a reboiler 1, a plurality of distillation columns 2 filled with a filler, and gas rising from the distillation column 2. The condenser 3 is housed in a vacuum heat insulating container 4. The reboiler 1, the distillation column 2, and the condenser 3 are supported by a heat insulating container 4 via a support member (not shown).

The reboiler 1 is provided with a plurality of throw-in type sheathed heaters 6 for heating the staying liquid in the reboiler container 5, which are arranged vertically in the bottom surface 5 a of the reboiler container 5 and arranged in a horizontal direction. . The sheath heater 6 is operated by an external power supply 8.

The reboiler container 5 is provided with a terminal box 7 for accommodating the terminal portion of the sheathed heater 6 drawn out of the reboiler container 5, which is also accommodated in the vacuum heat insulating container 4 like the reboiler container 5.

In the condenser 3, a condensing tube 10 provided at the upper end of each distillation column 2 is immersed in the refrigerant liquid in the condenser vessel 11 to condense the condensable gas rising from the distillation column 2. The condensed liquid generated in the condensing tube 10 flows down to the distillation column 2 by natural flow. The material to be distilled is sent to the middle stage of the distillation column 2, and the low-boiling components are withdrawn from the top of the condensing tube 10 and the high-boiling components are withdrawn from the reboiler vessel 5.

The sheath heater 6 provided in the reboiler 1
Are connected in parallel in the terminal box 7 as shown in FIG. The sheath heater 6 is limited to a required height so as not to unnecessarily increase the liquid holding amount. The amount of heat generated by each sheathed heater 6 is limited so that a heat flux required for stable boiling can be obtained, and the required amount of heat is ensured by increasing the number of installed heaters.

Further, since the terminal portion 13 and the wiring of the sheathed heater 6 are housed in the vacuum heat insulating container 4, it is possible to avoid a problem that the electrical insulation is deteriorated due to dew condensation. Further, it is possible to avoid a decrease in heat insulation performance due to heat input from the peripheral portion of the terminal portion 13 of the sheathed heater 6.

FIG. 3 shows a second embodiment of the reboiler according to the present invention. Here, a casting heater 21 is mounted on the outer surface of the reboiler container 5. Casting heater 2
1, a partition 2 having the required airtightness and pressure resistance, which separates it from the vacuum section 22 in the vacuum heat insulating container 4.
3 is provided, and an empty room 24 inside the partition 23 is provided.
Is filled with nitrogen. The partition 23 has a U-shaped cross section, and is provided in a ring shape so as to cover the cast heater 21 provided over the entire periphery of the peripheral wall of the reboiler container 5.

As a result, the contact portion between the casting heater 21 and the reboiler vessel 5 is covered with a nitrogen filling layer, and the nitrogen filling the minute gap between the casting heater 21 and the reboiler vessel 5 acts as a heat transfer medium. Thus, a decrease in heat transfer efficiency is avoided. Furthermore, the terminal portion 25 of the cast heater 21 is also accommodated in the partition 23 and covered with nitrogen, thereby preventing a decrease in electrical insulation.

[0022]

As described above, according to the present invention, by arranging a plurality of throwing heaters on the bottom of the reboiler container in a horizontal direction, a heat flux required for a stable boiling state is secured, and at the same time, the liquid holding amount is maintained. Can be avoided, and the distillation time can be improved by shortening the concentration time. Further, by housing the terminal portion of the electric heater in the vacuum heat insulating container, it is possible to avoid a decrease in electrical insulation and a decrease in heat insulation performance. Further, by enclosing nitrogen around the cast heater in a structure in which the reboiler is housed in the vacuum insulated container, it is possible to avoid a decrease in heat transfer efficiency and a decrease in electrical insulation.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a reboiler according to the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a distillation apparatus to which the reboiler shown in FIG. 1 is applied.

FIG. 3 is a sectional view showing a second embodiment of the reboiler according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reboiler 2 Distillation column 3 Condenser 4 Vacuum insulated container 5 Reboiler container 6 Seed heater 7 Terminal box 8 Power supply 10 Condenser tube 11 Condenser container 13 Terminal part 21 Cast-in heater 22 Vacuum part 23 Partition 24 Vacancy 25 Terminal part

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kiichiro Narige 1033-8 Michi Nobe, Kamagaya City, Chiba Prefecture (72) Inventor Shoji Tanaka 4-12-22, Okamura, Isogo-ku, Yokohama, Kanagawa Prefecture (72) Inventor Minoru Terano Kanagawa 1-1-5 Iwamacho, Hodogaya-ku, Yokohama-shi F-term (reference) 4D076 AA22 AA24 BB04 BB05 BC06 CA19 CD22 DA02 DA10 DA14 DA22 FA31 FA37 JA03

Claims (3)

[Claims] 1. A reboiler configured to heat a liquid retained in a reboiler container by an electric heater, wherein the electric heater is a throw-in heater immersed in the liquid retained in the reboiler container. A reboiler characterized in that a plurality of reboilers are provided side by side in a state of standing on a bottom surface. 2. A reboiler which is housed in a vacuum insulated container for enhancing heat insulation in low-temperature distillation and heats a liquid retained in a reboiler container by an electric heater, wherein said electric heater is provided in said reboiler container. A reboiler, which is a throw-in heater immersed in a stagnant liquid therein, wherein a terminal portion of the electric heater drawn out of the reboiler container is accommodated in the vacuum insulated container. 3. A reboiler housed in a vacuum insulated container for enhancing heat insulation in low-temperature distillation, wherein an electric heater is used to heat a liquid retained in the reboiler container, wherein the electric heater is provided in the reboiler container. A reboiler, comprising: a cast heater mounted on an outer surface of the electric heater, wherein a partition is provided to isolate a periphery of the electric heater from a vacuum portion in the vacuum heat insulating container, and nitrogen is sealed in the partition.