JP3031725B2 - Operating method of pervaporation membrane device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a pervaporation membrane apparatus for separating a liquid mixture, and more particularly to a partial condensation of evaporated raw liquid components which accumulate on the permeate side of a pervaporation membrane module during operation. The present invention relates to an operation method in which an object is removed after the operation is stopped and / or before the operation is restarted, and the operation is always started in a state where there is no condensate on the permeation side.

[0002]

2. Description of the Related Art In order to separate a liquid mixture, the vapor pressure of a substance to be separated on the permeation side must be lower than the vapor pressure on the supply side of the substance to be separated in a feed liquid (raw liquid).
As a specific method, there has been proposed a method in which the supply liquid is heated, and the vapor on the permeation side is cooled and condensed by a cooler or the like, and as a result, the pressure is reduced.

[0003]

However, when a pervaporation membrane apparatus based on such a principle is actually operated, some of the vapor evaporated on the supply side is condensed on the permeation side of the pervaporation membrane module, and as a result, There is a problem in that the resistance of the substance to be separated permeates the membrane, and the permeation speed gradually decreases, that is, the performance gradually decreases.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, when the pervaporation membrane device is operated intermittently, a specific operation method is adopted. The present invention has been found that the liquid mixture can be separated efficiently.

That is, the present invention relates to a membrane apparatus equipped with a pervaporation membrane module for bringing a liquid mixture into contact with a pervaporation membrane and selectively permeating and separating the liquid component. After draining the undiluted solution on the supply side of the membrane module, open the supply side to atmospheric pressure air and dry the permeate side of the pervaporation membrane module after the operation is stopped and / or before resuming operation, and condensing the permeate side. A method for operating a pervaporation membrane device, comprising removing an object, restoring the performance of the pervaporation membrane module, and restarting the operation.

In the present invention, the method of drying the permeation side of the pervaporation membrane module and removing the condensate on the permeation side is not particularly limited as long as the performance of the pervaporation membrane module can be recovered, but preferably the following method is used. Can be adopted.

The first method is to remove the condensate on the permeate side by evaporating and removing the condensate on the permeate side by reducing the pressure on the permeate side with a vacuum pump and permeating the whole amount of room temperature or heated atmospheric pressure air through the membrane. is there. The operating conditions at this time are generally as follows: the permeate side pressure is 5 to 300 mmHg, and the atmospheric pressure air at room temperature to 80 ° C is 0.
The entire membrane may be permeated for 5 to 5 hours.

The second method is a method in which condensate on the permeate side is removed by evaporation by sending room temperature or heated atmospheric air from one side of the supply side to the other side. The operating conditions at this time are usually as follows.
It is sufficient to blow air at a rate of 1 liter / min or more for 0.5 to 6 hours.

[0009] The third method is to evaporate the condensate on the permeate side by opening the permeate side to atmospheric pressure air, sending room temperature or heated pressurized air to the supply side, and permeating the entire membrane. It is a method of removing by removing. The operating conditions at this time are:
Usually, room temperature to 80 ° C., a pressure 1 kgf / cm ² or more pressurized air 0.
The entire membrane may be permeated for 5 to 5 hours.

As another method, a method may be used in which the condensate on the permeation side is evaporated and removed by allowing the condensate on the permeate side to stand naturally for a predetermined time.

The operating method according to the present invention can be applied to any type of pervaporation membrane apparatus equipped with a pervaporation membrane module, and is not limited to any particular type.

[0012]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A permselective composite membrane having an active thin film of about 3 μm thick crosslinkable silicone resin on a polyimide ultrafiltration membrane was prepared by
Envelope-shaped membrane leaf, 4 membrane leaf are made of 0.62 mm thick polypropylene net stock solution spacer and 1.25 mm thick
Was wound around an air collecting tube together with a polypropylene-made permeated gas spacer to form a spiral-type pervaporation membrane module having an element diameter of 95 mm and a length of 1 m.
FIG. 1 shows a degassing membrane device equipped with such a pervaporation membrane module.

A 2.0 wt% aqueous ethanol solution at 60 ° C. as a stock solution is passed through the pervaporation membrane device at a flow rate of 3 liter / min, and the pervaporation operation is performed for 15 hours while maintaining the permeate side pressure at 70 mmHg. Operation 1) was performed.

After the operation was completed, the valves 14 and 18 were closed, and the valves 15 and 16 were opened to remove the stock solution from the supply side of the pervaporation membrane module, and the supply side of the module was opened to atmospheric pressure air. After a lapse of 2 hours, the heaters 11 and 12 were turned on, and the vacuum pump 5 was operated at a pressure of 50 mmHg so that the entire amount of air at 60 ° C. permeated through the membrane for 1 hour.

Thereafter, a pervaporation operation was performed for 15 hours under the same conditions as in the above-mentioned operation 1 (operation 2)).

Table 1 shows the vapor permeation rates in the initial and final stages of the operations 1 and 2.

Comparative Example A pervaporation membrane device equipped with the same spiral-type pervaporation membrane module as in Example 1 was provided.
A 2.0 wt% ethanol aqueous solution at 60 ° C is flowed at 3 liter / mi.
Then, a pervaporation operation (operation 1) was performed for 15 hours while passing the liquid at n and maintaining the pressure on the permeation side at 70 mmHg.

After the operation, the raw solution was left on the supply side of the pervaporation membrane module for 3 hours with the undiluted solution.
Thereafter, a pervaporation operation was performed for 15 hours under the same conditions as in Operation 1 (Operation 2). Table 1 shows the vapor permeation rates in the initial and final stages of Run 1 and Run 2.

Example 2 A degassing membrane device (FIG. 2) equipped with a spiral type pervaporation membrane module similar to that of Example 1 was used.
A pervaporation operation (operation 1) was carried out for 15 hours while passing a 0 wt% ethanol aqueous solution at a flow rate of 3 liter / min and maintaining the permeate pressure at 70 mmHg.

After the operation is completed, the valves 14, 18 are closed, and the valves 15, 16 and 17 are opened to remove the stock solution from the supply side of the pervaporation membrane module, and the supply side of the module is opened to atmospheric pressure air. did. After 2 hours, the valve 17 is closed, the heater 11 and the blower 13 are turned on,
° C air was blown at a flow rate of 200 Nl / min for 1 hour.

Thereafter, a pervaporation operation was performed for 15 hours under the same conditions as in Operation 1 (Operation 2). Driving 1
Table 1 shows the vapor permeation rates at the initial and final stages of the operation 2.

[0023]

[Table 1]

[0024]

According to the method of the present invention, in a pervaporation membrane apparatus which is operated intermittently, a condensate of a raw liquid component evaporated on a supply side on a permeation side of a pervaporation membrane module during operation. Accumulates and becomes a resistance to the permeation of the substance to be separated through the membrane, and as a result, even if the performance of the pervaporation membrane device is reduced, the condensate can be removed by the evaporation operation during operation shutdown. There is an advantage that operation while maintaining the performance in the range becomes possible.

[0025]

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for implementing a method for operating a degassing membrane apparatus according to the present invention.

FIG. 2 is a schematic view of an apparatus for carrying out a method for operating a degassing membrane apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Undiluted-liquid supply part 2 Non-permeate liquid outflow part 3 Non-condensed gas outflow part 4 Condensate outflow part of membrane permeation vapor 5 Vacuum pump 6 Liquid supply pump 7 Cooler unit 8 Condensate discharge pump 9 Pervaporation membrane module 10 Raw liquid heating Heater 11, 12 Heater for membrane module drying 13 Blower 14-18 valve

Claims (1)

(57) [Claims] 1. A membrane apparatus equipped with a pervaporation membrane module for bringing a liquid mixture into contact with a pervaporation membrane and selectively permeating and separating the liquid component. After draining the undiluted solution on the supply side, open the supply side to atmospheric pressure air, and dry the permeate side of the pervaporation membrane module to remove condensate on the permeate side after stopping operation and / or before restarting operation. And recovering the performance of the pervaporation membrane module and restarting the operation.