JPH0677644B2 - Stage switching operation type distillation device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a distillation apparatus for distilling a raw material.

(Prior Art) A commonly used distillation apparatus is as shown in FIG.
A reboiler is arranged at the lower end of the distillation column, and a feed tank is connected in the middle of the distillation stage so that the raw material is supplied from the feed tank, and a condenser is arranged at the top so that the vapor is directed upward and the liquid is directed downward. Gas-liquid contact is made by flowing. Periodic distillation is operated by alternately repeating the vapor-only period (VFP) and the liquid-only period (LFP).

5 (b) and 5 (c) are structural views showing the specific constitution of the distillation column used in the distillation apparatus, of which the one shown in FIG. 5 (b) is of the bubble-bell tower type. The one shown in FIG. 5 (c) is of the packed tower type.

(Problems to be Solved by the Invention) However, an ordinary distillation column has the following drawbacks.

(1) In the bubble-bell tower type, liquid mixing occurs on the stage, resulting in a large energy loss. Further, in the packed tower type, there is a restriction on the weight of the entire tower and the like, so that it is difficult to increase the size of the apparatus.

(2) Since both the vapor and the liquid are flowing in the bubble-bell tower type and the packed tower type, the work and operation of startup (starting) and shutting down (termination) are troublesome.

(3) Depending on the type of raw material and product specifications, the required number of stages,
Since the optimum feed stage is determined, it is difficult to change the operating conditions.

(4) It is difficult to install additional equipment such as intermediate heating, cooling, or side cut easily.

(5) Since the more difficult it is to separate, the more stages are required, there is a limit to the number of stages in the vertical direction, and two or more towers are required.

On the other hand, in the cyclic distillation, a large energy saving effect can be obtained by eliminating the liquid mixing on the stage, but it was difficult to realize smooth liquid transfer during the period in which only the liquid was flown (LFP), so it was put to practical use. However, although the problem of liquid transfer was overcome, liquids with different compositions were mixed during the liquid flow period (LFP), resulting in a large energy loss. By adopting a reservoir, we tried to realize a smooth liquid flow and eliminate mixing of liquids with different compositions, but the tower height was increased by the height of the interstage liquid reservoir, and the improvement effect was diminished. Cases have been reported.

Therefore, an object of the present invention is to provide a stage-switching operation type distillation apparatus in which a plurality of batch units constituting a distillation stage are provided and the above-mentioned drawbacks are eliminated by the stage-switching operation.

(Means for Solving Problems) In order to achieve the above-mentioned object of the present invention, the present invention provides
A plurality of units that act as a distillation stage (including a buffer), a plurality of solenoid valves that sequentially connect each unit, a condenser that is connected to each unit via a solenoid valve, and a unit that is connected to each unit via a solenoid valve. There is provided a feed tank, and a stage switching operation type distillation apparatus for switching the distillation stage (including the buffer stage) of the unit by switching operation of the solenoid valve. Further, a stage switching operation type distillation apparatus in which heating / cooling equipment is provided in the distillation stage (including a buffer) is also provided.

In addition, a reboiler may be provided separately, and this reboiler may be connected to each unit or some of the units via solenoid valves, and a reservoir may be used instead of the unit acting as a buffer stage. The configuration used can be provided.

(Operation) The operation of the present invention will be described by typifying a distillation apparatus having a stage switching operation system in which a distillation stage (including a buffer) is provided with heating / cooling equipment.

(1) One of the units is a buffer stage, the other adjacent units are distillation stages (sequential first stage, second stage ... Nth stage), and the Nth stage is a reboiler stage.

(2) The reboiler stage is heated, and the generated vapor reaches the condenser while becoming vapor rich in low boiling point components while repeating vapor-liquid contact in each distillation stage.

(3) The condensate is first taken out as a distillate, and when the composition becomes low, the electromagnetic valve is switched and the condensate is transferred to the buffer stage as the reflux liquid.

(4) Stop heating when a predetermined time or state is reached,
The reboiler stage is separated from other connected distillation stages, and the liquid is taken out as a bottom product.

(5) At the same time, the buffer stage that stores the reflux liquid is used as the first stage and is combined with the connected distillation stage, and the first, second, ..., N-1 stages up to that point are respectively the second and third stages. , ..., Nth
Stage (reboiler stage). On the other hand, the reboiler stage emptied in (4) becomes a buffer stage, and the preparation for the next cycle is completed.

(6) Repeat (2) to (4).

(Example) FIG. 1 is a schematic block diagram showing an ideal design structure of a stage-switching operation type distillation apparatus of the present invention, and FIG. 2 is a schematic block diagram of a stage-switching operation system using a fixed reboiler. FIG. 3 is a schematic block diagram showing an embodiment of a practical stage switching operation system, and FIG. 4 is a schematic block diagram showing another example of a practical stage switching operation system.

In FIG. 1, 1a, 1b, 1c, 1d and 1e are units equipped with heating / cooling equipment, which are configured as distillation stages except one buffer stage. 2 is a condenser and 3 is a feed tank. Each unit is connected via an electromagnetic valve, each unit 1 and the condenser 2 are also connected via an electromagnetic valve, and further, the feed tank 3 is also connected via an electromagnetic valve. In this ideal design, the reboiler is replaced by the heating equipment of each unit. When it is not a reboiler stage, it can be used for auxiliary heating / cooling. The heating / cooling of the heating / cooling facility and the opening / closing of each solenoid valve are configured to be performed by an electronic control unit (not shown).

Operation 1 1e is a buffer stage, adjacent distillation stages 1a, 1b, 1c, 1d
Are sequentially designated as the first, second, third, and fourth stages, and the fourth stage is now the reboiler stage.

Operation 2 Open the solenoid valves Vt1, Vc1, Vc2, Vc3 and close the others.
Steam generated by heating the reboiler stage 1d is generated by the lines Lc3 and Lc.
2, Lc1, through the gas-liquid contact in each distillation stage 1c, 1b, 1a,
Reach the condenser via line Lt1.

Operation 3 For the condensate, first open the solenoid valve Vd and close Vq.
It is taken out as a distillate, and when the composition becomes low, the solenoid valve is switched (Vd closed, Vq open), the solenoid valve Vq5 is opened, and it passes through the line Lq5 and is transferred as the reflux liquid to the buffer stage 1a.

Operation 4 When a predetermined time or state is reached, heating is stopped and reboiler stage 1d is separated from other connected distillation stages (Vc3
Closed), open the solenoid valve Vb4, and take out the liquid as a canned liquid.

Operation 5 At the same time, Vq5 was closed, and the buffer stage 1e storing the reflux liquid was combined with the distillation stage connected as the first stage, and the distillation stages 1a, 1 that had worked as the first, second, and third stages up to that point were combined.
b and 1c function as the second, third and fourth stages, respectively.
On the other hand, the reboiler stage 1d which became empty in (3) closes Vb4 and becomes a buffer stage, and preparation for the next cycle is completed.

Next, the solenoid valves Vt5, Vc5, Vc1, Vc2 are opened. Reboiler stage 1c
The generated steam passes through lines Lc2, Lc1.Lc5 and undergoes gas-liquid contact in each distillation stage 1b, 1a, 1e, and line Lt5.
To reach the condenser. Thereafter, the same operation is repeated to carry out distillation. The feed liquid is supplied from the feed tank 3 to the optimum feed stage through the line Lf by opening the solenoid valve Vf in the operation 2. 5 (5
a, 5b, 5c, 5d) is a backflow prevention device for vapor and liquid,
It is for flowing steam or liquid in only one direction.

The embodiment shown in FIG. 2 will be described. Vc (Vc1, Vc2, Vc3, Vc
4) is the line placed between each unit 1 (1a, 1b, 1c, 1d)
This is a solenoid valve provided on Lc (Lc1, Lc2, Lc3, Lc4). Vt (Vt
1, Vt2, Vt3, Vt4) are solenoid valves provided in the line Lt (Lt1, Lt2, Lt3, Lt4) from each unit 1 to the condenser 2. Vb (Vb1, Vb2, Vb3, Vb4) is the line Lb (Lb1, Lb2, Lb3, Lb) arranged between the bottom of each unit 1 and the reboiler 4.
This is the solenoid valve provided in 4). Vq (Vq1, Vq2, Vq3, Vq4) is the line Lq (Lq1, Lq from the capacitor 2 to each unit 1
2, Lq3, Lq4) is a solenoid valve. Vs (Vs1, Vs2, Vs3, V
s4) is a solenoid valve provided for the side cut of each unit 1. Vf is a solenoid valve provided in the line Lf connecting the feed tank 3 to the line Lq. The piping attached to the unit is provided with a vapor or liquid backflow prevention device 5 as required. Although not shown in the figure, the lines Lb and Lq have a pressure equalizing line in addition to this for smoothing the liquid flow.

In this method, other kinds of control measures can be performed by a program, but here, a typical operation for heating the reboiler on and off will be described.

1d is a buffer stage, adjacent distillation stages 1a, 1b, 1c are sequentially the first,
The second and third stages. One cycle of periodic distillation operation now
DP (distillate removal period), RP (reflux liquid storage period), EP
It is divided into four operation modes: (stage liquid discharge period) and FP (stage liquid replenishment period).

Open the DP solenoid valves Vt1, Vc1, Vc2, Vr3 and close the other solenoid valves. The steam generated by heating the reboiler is generated by lines Lr3 and Lc.
2, Lc1, through the gas-liquid contact in each distillation stage 1c, 1b, 1a,
Furthermore, it reaches the condenser via line Lt1. Open the solenoid valve Vd to take out the condensed liquid as a distillate.

The RP solenoid valve is switched (Vd closed, Vq open), Vq4 is opened, and the condensed liquid having a low composition is transferred to the buffer stage 1d as the reflux liquid through the line Lq4. When the predetermined time or state is reached, heating is stopped.

EP Open the solenoid valve Vr, close Vr3, take out the reboiler liquid as a bottom liquid, and then close Vr.

Open the FP solenoid valve Vb3, close Vq and Vq4, and transfer the liquid of 1c to the reboiler. At the same time, the buffer stage 1d that was storing the reflux liquid was used as the first stage and was combined with the connected distillation stage, and the distillation stages 1a and 1b that had been functioning as the first and second stages up to that point were respectively designated as the second and third stages. Make it work. On the other hand, the third EP emptied
Stage 1c becomes a buffer stage. Further, the solenoid valve Vf is opened here, the feed liquid is supplied to the optimal feed stage through the lines Lf and Lq, and when completed, Vf is closed and the preparation for the next cycle is completed.

Next, a practical embodiment of the stage-switching operation type distillation apparatus of the present invention will be described with reference to FIGS. 3 and 4, and the basic operation in FIGS. 3 and 4 is that of FIG. Since both are similar, only a brief description will be given.

FIG. 3 shows an embodiment in which the units are divided into upper 1U and lower 1L unit groups in consideration of the temperature level of the piping system, and the stage switching operation is performed in each group. Here, the buffer stage of the lower unit group 1L is the operation mode in FIG.
Serves as a buffer stage for the liquid moving from the upper unit group 1U in EP.

In Figure 4, the units are upper 1U, middle 1M and lower
This is an example in which the unit is divided into 1 L unit groups and the stage switching operation is performed in each group. Here, the buffer stages of the middle unit group 1M and the lower unit group 1L are, as in FIG. 3, the buffer stages of the liquid moving from the upper unit group 1U and the middle unit group 1M in the operation mode EP. Work as.
However, in this embodiment, a certain correspondence is provided between the upper unit group 1U and the middle unit group 1M, and the number of solenoid valves in the middle unit group is reduced. The transition order of the stages determines the transition order of the stages of the middle unit group 1M.

(Effects of the Invention) As described in detail above, in the present invention, since a plurality of units are provided and the stage switching operation is performed, it is possible to eliminate liquid mixing on the stage and reduce energy loss. It also makes startup and shutdown easier. Further, the number of stages and the feed stages can be freely selected only by changing the program of the electronic control unit, although they are the same device.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an ideal design structure of a stage-switching operation type distillation apparatus of the present invention, FIG. 2 is another schematic block diagram showing an ideal design structure, and FIG.
FIG. 5A is a schematic block diagram showing an embodiment of an actual stage-switching operation type distillation apparatus, FIG. 4 is a schematic block diagram showing another embodiment of an actual stage-switching operation type distillation apparatus, and FIG.
FIG. 5 is a schematic block diagram of a conventional distillation apparatus, and FIGS. 5B and 5C are configuration diagrams of a conventional distillation column. 1 ... Batch unit, 2 ... Condenser, 3 ... Feed tank, 4 ... Reboiler.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidekazu Kurimoto 1017-3, Higashioosonemachi, Kita-ku, Nagoya-shi, Aichi (56) References JP-A-55-167002 (JP, A)

Claims (5)

[Claims] 1. A plurality of units functioning as a distillation stage (including a buffer), a plurality of solenoid valves for sequentially connecting the units, a condenser connected to each unit via a solenoid valve, and a solenoid valve for each unit. And a feed tank connected via a column, and the stage switching operation type distillation apparatus is characterized in that the distillation stage (including the buffer stage) of the unit is switched by a switching operation of the solenoid valve. 2. The stage-switching operation type distillation apparatus according to claim 1, wherein the reboiler is connected to each unit or some of the units via a solenoid valve. 3. A stage-switching operation type distillation apparatus as set forth in claim (1), characterized in that the distillation apparatus is composed of a unit having a heating / cooling facility. 4. A liquid reservoir is used in place of the unit acting as a buffer stage.
The stage-switching operation-type distillation apparatus according to item (2) or (3). 5. A plurality of units are grouped into several categories to form a group, and a stage switching operation is performed in each group. A scope of claims (1) or (2) or The stage-switching operation type distillation apparatus according to item (3) or (4).