JPH0699338B2 - Alcohol distillation device with heat recovery and power recovery device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alcohol distillation apparatus having two or more distillation column units and a heat recovery unit and a power recovery unit, and more particularly to a heat pump for recovering the heat of the overhead fraction in such a unit. , A combination with a heat pump driving device that effectively uses thermal energy of steam generated in a steam boiler.

[0002]

2. Description of the Related Art In a conventional alcohol distillation apparatus having two or more conventional distillation column apparatuses, as shown in FIG. 2, the overhead fractions of any of the distillation columns 50, 60 and 70 are converted into a conventional condenser 52. , 62, 72 were cooled by sensible heat of the cooling water to be condensed, and the cooling water of which temperature was raised by obtaining heat from the overhead fraction was directly discharged to the outside of the system. That is, the heat of the overhead fraction was released to the atmosphere without being used. On the other hand, in order to supply the steam required by the alcohol distillation apparatus, the steam boiler 58 generates a required amount of steam. When the generated steam is pressure-reduced to a low-pressure steam having a predetermined working pressure, most of the steam generated in the steam boiler 58 does not recover heat energy as power through a back pressure turbine or the like, and simply uses the steam pressure reducing valve 56. Through the on-off valves 54, 64, 74 to reduce the pressure to a predetermined pressure through the distillation columns 50, 6
0, 70.

[0003]

As described above, the conventional alcohol distillation apparatus does not effectively use the heat of the overhead fraction, nor does it utilize the steam generated in the steam boiler with high thermal efficiency. Therefore, it was an economical device with low thermal efficiency. The reason why the heat of the overhead fraction is not used in the conventional alcohol distillation apparatus is that the temperature level of the heat is low and it is not easy to recover it, and the heat capacity is not so large, for example, large-scale recovery of waste heat boilers and the like. This is because it was difficult to adopt the method.
On the other hand, the reason why the steam generated in the steam boiler cannot be used with high thermal efficiency is that the amount of steam used in the alcohol distillation column apparatus, for example, the amount of steam used as a heat source in the distillation column, produces hydrous alcohol or produces anhydrous alcohol. This is because it is difficult to apply the conventional power recovery device such as a back pressure turbine because it largely varies depending on the type of the raw material liquid such as scabbard or the operating conditions of the distillation column such as the amount of the raw material liquid processed. .

In view of the above problems, it is an object of the present invention to realize a high heat efficiency by combining the use of heat from the overhead fraction and the effective use of the thermal energy of the steam generated in a steam boiler. And an alcohol distillation apparatus having a power recovery device.

[0005]

The above object can be achieved by a distillation column apparatus having the following features according to the present invention. The distillation column apparatus is an alcohol distillation apparatus having two or more distillation column apparatuses, and at least one distillation column apparatus of the two or more distillation column apparatuses has a top fraction of the distillation column and cooling water. A condenser / evaporator that generates steam by heat exchange with the screw, a screw-type steam compressor that pressurizes the generated steam, and a drive device for the screw-type steam compressor, and the drive device is a plurality of steam expanders. And a parallel gear with a one-way clutch capable of connecting at least one of these steam expanders to a screw-type steam compressor, and an electric motor provided between the screw-type steam compressor and the parallel gear with a one-way clutch. An alcohol distillation apparatus having a heat recovery unit and a power recovery unit.

The present invention is intended for an alcohol distillation apparatus having two or more distillation column apparatuses, as compared to the case where the present invention is applied to a small-scale apparatus having one distillation column, as compared with the case where two or more distillation column apparatuses are used. This is because the effect of the present invention is more remarkable when the present invention is applied to a large-scale alcohol distillation complex having the above. Of course, the present invention can be applied to an alcohol distillation apparatus having only one distillation column apparatus. It is not always necessary to provide a heat pump and a heat pump driving device in which a condenser / evaporator and a screw type steam compressor are combined in all of two or more distillation column devices. If it is preferably installed in a distillation column apparatus having a large throughput, a large amount of heat energy can be recovered.

The equipment used in the present invention is conventionally known unless otherwise specified. Further, there are no particular restrictions on the type and properties of the alcohol raw material liquid distilled by the alcohol distillation apparatus of the present invention. The condenser / evaporator is a heat exchanger such as a conventionally known shell-and-tube heat exchanger, box-type heat exchanger, and the like, as long as it has a heat transfer surface and can exchange heat between fluids. There are no restrictions. For example, using a multi-tube heat exchanger, water is passed through the tube side and the bottom fraction is passed through the barrel side. Also, each can be run on the opposite side.
The reason why a screw-type steam compressor is used to raise the pressure of the vapor generated in the condenser / evaporator to a predetermined pressure is that the screw-type steam compressor does not change even if the conditions on the primary side and the secondary side change to some extent. This is because it is possible to freely follow changes. The pressurized steam is used for heating the distillation column and the like.

The steam expander is a screw type steam expander,
It is a known steam expander such as a turbine type steam expander. A parallel gear with a one-way clutch is a known device that can connect at least one of a plurality of steam expanders, that is, a required number of steam expanders to a screw-type steam compressor, if desired. When the steam expanders are connected, only the driving power of the steam expanders is transmitted to the screw steam compressor, and when the multiple steam expanders are connected, the sum of the driving power of the multiple steam expanders becomes the screw steam. Transmitted to the compressor. The electric motor provided coaxially between the screw-type steam compressor and the parallel gear with the one-way clutch has both a function as an auxiliary drive of the screw-type steam compressor and a function as a generator. Adjust the difference between the required power of the screw steam compressor and the required amount of low-pressure steam. When the load of the screw-type steam compressor is large, the low-pressure steam requirement is small, and if the driving power is insufficient due to the small number of steam expanders being driven accordingly, the electric motor is Working together as an auxiliary drive. On the contrary, when the load of the screw-type steam compressor is small and the required amount of low-pressure steam is large and the driving power becomes excessively large because it is driven by a large number of steam expanders, the electric motor is By working as a generator, the thermal energy of steam is converted into electrical energy to improve thermal efficiency.

By the heat pump in which the above condenser / evaporator and the screw type steam compressor are combined, the heat of at least one overhead fraction of the two or more distillation columns is converted into steam and recovered. The amount of steam generated in the steam boiler can be reduced by the amount of recovered steam. Further, the present invention, by providing a plurality of steam expanders in the heat pump drive device, when the required power of the heat pump is large and the required amount of low-pressure steam is large, a large number of steam expanders are operated as necessary. When the required power of the heat pump is small and the required amount of low-pressure steam is also small, a small number of steam expanders are operated, and the thermal energy of the steam generated in the steam boiler is recovered as a power source while stepping down to low-pressure steam with high thermal efficiency. be able to. Preferably, the ratios of the respective capacities of the plurality of steam expanders are calculated in a geometric progression ratio, for example, 1: 0.5: 0.25.
Like As a result, a plurality of steam expanders having different capacities can be combined to more effectively use the heat energy of steam. The present invention has two advantages from the above two points.
It is possible to improve the thermal efficiency of the distillation column apparatus having more than one base. Hereinafter, the present invention will be described in more detail based on examples with reference to the accompanying drawings.

[0010]

EXAMPLE An example apparatus of a distillation column apparatus according to the present invention will be described with reference to FIG. Distillation tower apparatus 10 shown in FIG.
Is one of alcohol distillation apparatuses having two or more distillation column apparatuses according to the present invention, in which steam is generated by a condenser / evaporator, and the generated steam is pressurized by a screw-type steam compressor to a predetermined value. It is a distillation column apparatus having a heat pump that recovers the heat of the overhead fraction by using high-pressure steam, and a drive device that effectively uses the steam generated in a steam boiler to drive the heat pump. Among the alcohol distillation apparatuses having two or more distillation column apparatuses according to the present invention, the distillation column apparatus having no such heat pump and heat pump driving apparatus is the same as the conventional distillation column apparatus described above.
The distillation column apparatus 10 includes a distillation column 12 and an overhead fraction of the distillation column 12 which is cooled and condensed with water, while water is evaporated by heat obtained from the overhead fraction to generate vapor, which is condensed / evaporated. The container 14 is provided with a screw type steam compressor 16 for increasing the pressure of the generated steam to a predetermined pressure, and a drive device 18 for driving the screw type steam compressor 16.

The drive unit 18 has two steam expanders 20A and 20B having a capacity of 2: 1 and one or both of these two steam expanders connected to the screw type steam compressor 16 at the same time. It has a parallel gear 22 with a one-way clutch that can be installed, and an electric motor 24 coaxially provided between the screw type steam compressor 16 and the parallel gear 22 with a one-way clutch. For the sake of simplicity, equipment for heating the bottom of a distillation column not directly related to the present invention, a pump for extracting the bottom fraction, a reflux pump for refluxing a part of the condensed top fraction to the top, a top fraction The minute delivery pump, the control device, and the like are not illustrated or described unless necessary.

The overhead fraction of the distillation column 12 is the condenser / evaporator 1
The water flows on the body side of No. 4 and the heat is taken away by the water flowing on the tube side to condense. On the other hand, the water flows through the pipe 26 on the tube side of the condenser / evaporator 14 to obtain heat from the overhead fraction flowing on the cylinder side and evaporate to become steam. In addition, the softened water is preferably supplied to the condenser / evaporator 14. The pressure on the tube side of the condenser / evaporator 14 is a pressure at which water, which has obtained heat from the overhead fraction, can be vaporized to vapor, and the screw type steam compressor 16 sucks it to reach that pressure. To be done. The generated steam passes through the pipe 28 and the screw type steam compressor 1
It is sucked into 6, where it is pressurized to a predetermined pressure and supplied to the bottom of the distillation column 12 as a heating source.

The steam supplied from the external steam boiler 40 through the pipe 32 is used as an opening / closing valve 34A and / or 34B.
Is introduced into the steam expanders 20A and / or 20B to become a driving power source for the screw-type steam compressor 16, and the pressure of the self is reduced to become low-pressure steam having a predetermined pressure, which is supplied to the other distillation columns 42 and 44, respectively. It is supplied via the on-off valves 36 and 38.

When a large amount of low pressure steam is required, for example, when both distillation columns 42 and 44 are operated, the on-off valve 34A,
When both the steam expanders 20A and 20B are operated by opening both of the steam generators B to expand the steam of an amount commensurate with the required amount into the low pressure steam, when the required amount of the low pressure steam is small, for example, the distillation columns 42 and 44.
When operating only one of the above, the on-off valve 34A,
Only one of B is opened to expand steam expanders 20A, B
Either one of them is operated to expand a low-pressure steam in an amount corresponding to a small required amount. The load on the screw-type steam compressor 16 is large compared to the required amount of low-pressure steam.
When the motive power of only one or two steam expanders 20 is insufficient, the electric motor 24 is driven as an auxiliary drive device in conjunction with the steam expanders 20. On the contrary, the load of the screw type steam compressor 16 is smaller than the required amount of low pressure steam,
When the power of one or two steam expanders 20 becomes excessive, the electric motor 24 acts as a generator to convert the heat energy of steam into electric energy. In this embodiment, the vapors output from the vapor expanders 20A and 20B are directly supplied to the distillation columns 42 and 44 via the on-off valves 36 and 38, respectively, but this method is not always necessary. Instead, for example, combine the steam from the steam expanders 20A and 20B into one steam header,
Then, the on-off valves 36 and 38 can be opened and closed to supply them to predetermined places, for example, distillation columns 42 and 44 of other series. The distillation columns 42 and 44 are provided with ordinary condensers 46 and 48 which are cooled by sensible heat of cooling water in order to condense the respective overhead fractions.

Experimental data for operating the device 10 of the present embodiment will be described below. Experimental Example 1 Experimental Example 1 is a case where only the steam expander 20A is driven because the required amount of low-pressure steam is small. The alcohol vapor at a temperature of 80 ° C distilled from the top of the distillation column 12 is condensed /
Evaporator 14 uses 0.45ata and 78 ° C steam at 5.8T /
Hr evaporated. The vaporized steam was pressurized to 1.34 at 108 ° C. by a screw type steam compressor 16 and supplied to the bottom of the distillation column 12 as a heating source. On the other hand, 14 ata of steam 4.8 T / Hr was generated by a steam boiler, introduced into the steam expander 20A and expanded to an outlet pressure of 1.8 ata to generate driving power for the screw steam compressor 16. 1.8 ata steam of 4.8 T / Hr emitted from the steam expander 20A was supplied to a distillation column apparatus of another series. In addition, since the power of the steam expander 20A was insufficient for the load of the screw-type steam compressor 16, the electric motor of the auxiliary drive machine was driven to consume 400 Kw of electric power.

Comparative data were collected under the same operating conditions as in Experimental Example 1 except that the conventional distillation column apparatus shown in FIG. 2 was used. In order to supply steam to the distillation column apparatus of another series through the distillation column 12 and the valves 58 and 60, it was necessary to generate a steam amount of 10.6 T / Hr with the steam boiler. Economic calculation assuming that the steam unit price is 2,500 yen / Ton and the power unit price is 15 yen / Kwh, the amount of live steam from a steam boiler is 5.8 T / Hr (10.6-4). .8 = 5.8)
Since it has been reduced and the power consumption has increased by 400 Kwh,
A cost reduction of 8,500 yen / hr has been made possible, reducing 32% of the conventional utility cost.

Experimental Example 2 Experimental example 2 is a case where two steam expanders 20A and 20B are driven because a large amount of low pressure steam is required. The operating conditions of the heat pump composed of the condenser / evaporator 14 and the screw-type steam compressor 16 were the same as in Experimental Example 1.
The steam boiler generates 7.4T / Hr of steam and 4.8
T / Hr to steam expander 20A 2.6T / Hr to steam expander 20
Introduced into B, generated power to expand to low pressure steam.
Since the power of the steam expanders 20A and 20B alone is insufficient for the load of the screw-type steam compressor 16, the electric motor of the auxiliary drive machine was driven to consume 250 Kw of electric power. On the other hand, the conventional distillation column apparatus shown in FIG. 2 requires 13.2 T / Hr as the total vapor amount, and the vapor amount was generated by the steam boiler. When the economic trial calculation is performed in the same manner as in Experimental Example 1, the steam generation amount in the steam boiler is reduced by 5.8 T / Hr (13.2-7.4 = 5.8) compared with the conventional device, and the power consumption is reduced. The amount has increased by 250 Kwh, so the deduction is 10,8
A cost reduction of ¥ 00 / Hr has been made possible, reducing 33% of the conventional utility cost.

The present invention combines a heat pump consisting of a condenser / evaporator and a screw-type steam compressor, and a heat pump drive device having a plurality of vapor expanders, a parallel gear with a one-way clutch, and an electric motor. Therefore, firstly, by using a heat pump, the heat of the overhead fraction of the distillation column apparatus is converted into steam and recovered, and it is possible to reduce the steam generation amount in the steam boiler by the recovered steam amount. 2 is provided with a plurality of steam expanders and an electric motor in the heat pump drive device, and adjusts the number of operating steam expanders for driving the heat pump according to the required amount of low-pressure steam. By adjusting the excess and deficiency power by the electric motor that functions as a generator, while completely recovering the thermal energy of the steam generated in the steam boiler as the power source. To step down to the low pressure steam have thermal efficiency.
As a result, the utility cost of the alcohol distillation apparatus can be reduced by about 30%. Therefore, the present invention, by recovering the heat of the overhead fraction of low temperature level, and by effectively utilizing the steam generated in the steam boiler,
It is possible to realize an alcohol distillation apparatus with low operating cost.

[Brief description of drawings]

FIG. 1 is a systematic diagram of a part of an alcohol distillation apparatus having two or more distillation column apparatuses according to the present invention.

FIG. 2 is a system diagram of a part of a conventional alcohol distillation apparatus having two or more distillation column apparatuses.

[Explanation of symbols]

 10 Distillation Tower Device of Examples According to the Present Invention 12, 42, 44 Distillation Column 14 Condenser / Evaporator 16 Screw Type Steam Compressor 18 Drive Device 20 Steam Expander 22 Parallel Gear with One-Way Clutch 24 Electric Motor 34, 36, 38 Open / close valve 40 Steam boiler 46, 48 Condenser 50, 60, 70 Distillation tower 52, 62, 72 Condenser 54, 64, 74 Open / close valve 56 Steam pressure reducing valve 58 Steam boiler

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takehiko Takahashi 8-12-307, Konakadai, Chiba-shi, Chiba (72) Inventor Masahiro Wakabayashi 3-3-3 Tomioka, Urayasu, Chiba E308

Claims (2)

[Claims] 1. An alcohol distillation apparatus having two or more distillation column apparatuses, wherein at least one distillation column apparatus among the two or more distillation column apparatuses comprises a top fraction of a distillation column and cooling water. A condenser / evaporator that generates steam by heat exchange, a screw-type steam compressor that pressurizes the generated steam, and a drive device for the screw-type steam compressor, and the drive device is a plurality of units. Provided between a steam expander, a parallel gear with a one-way clutch capable of connecting at least one of these steam expanders to the screw type steam compressor, and between the screw type steam compressor and the parallel gear with the one-way clutch. An alcohol distillation apparatus having two or more distillation columns. 2. The alcohol distillation apparatus having two or more distillation column apparatuses according to claim 1, wherein the capacity ratio of each of the plurality of vapor expanders is a geometric progression ratio. .