JP2006224019A - Cylindrical membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical membrane module capable of reliably drawing out condensate in which vapor to be treated is condensed in a membrane module without stopping an operation. <P>SOLUTION: The cylindrical membrane module is provided with a cylindrical main body 11 having opening parts on both ends, tube plates 12a, 12b mounted on at least one end of the main body and channels 13a, 13b which are mounted on the opening parts of the main body so as to cover the tube plates and have permeating vapor take-out ports 16. Therein, opening ends of a plurality of tubular separation membrane bodies 14 with the sealed top ends are further mounted on the tube plates to form separation membrane body groups 14a of a cantilever type. The main body 11 is set obliquely and a liquid reservoir mechanism 30 is disposed on the lower part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical membrane module, and more particularly to a so-called VP (vapor permeation) membrane module that is applied when an object to be processed is steam.

  A method for separating a liquid mixture by pervaporation has already been disclosed in US Pat. No. 2,953,502.

  This membrane separation method is conventionally performed by a liquid mixture that could not be separated by a simple method, for example, an azeotropic mixture such as ethanol / water, n-propanol / cyclohexane, a mixture system having a close boiling point and a low relative volatility, and heating. It attracts attention as a method for separating or concentrating a mixture containing a substance that causes polymerization or modification.

  Regardless of organic membranes or inorganic membranes, the smallest unit for industrial application is a membrane module. However, in the pervaporation membrane module, “a high-temperature organic substance is contained in the liquid to be treated.” “In principle, the permeate changes phase from the liquid to the gas phase during the permeation of the membrane, so it is necessary to replenish latent heat. There are many limitations that other membrane separation methods do not have, such as “There is a driving force for membrane permeation because the vapor pressure is the partial pressure of vapor, and the vapor pressure loss on the permeate side must be reduced.”

  On the other hand, when the supply (object to be processed) is steam, there is no phase change of the supply (object to be processed), so it is not necessary to supply steam latent heat in the membrane module. It is necessary to prevent condensation.

When the vapor condenses in the membrane module due to heat loss, the membrane surface of the membrane module is covered with the condensate, so that there is a problem that the separation efficiency and the permeation flux are lowered. For this reason, conventionally, a steam compressor or a super heater is provided on the inlet side of the membrane module to increase the pressure or temperature of the steam to be treated, thereby preventing condensation of the steam that is to be treated.
U.S. Pat. No. 2,953,502

  However, the operation of steam compressors and super heaters not only requires a lot of energy (power consumption), but the use of steam compressors and super heaters makes the system complex and avoids cost increases. There is a problem that can not be.

  On the other hand, when the condensate accumulates in the membrane module, it is necessary to discharge the condensate outside the membrane module, but during the drainage, the vapor in the membrane module leaks to the outside, or air from the outside etc. When the water flows in, the pressure in the membrane module fluctuates, and there is a problem that it becomes impossible to operate.

  In addition, when air flows into the membrane module from the outside, in addition to fluctuations in pressure in the membrane module, there is a risk of explosion, so an emergency stop of the operation is forced. Furthermore, when the periphery of the membrane is covered with the condensate, there is also a problem that it does not function as a separation membrane.

  The present invention has been made to solve such problems, and the object of the present invention is to operate a condensate caused by condensation of supply steam (processed steam) in the membrane module. An object of the present invention is to provide a cylindrical membrane module having a function of reliably extracting without stopping.

  In order to solve the above problems, the present invention is configured as follows.

  A cylindrical membrane module according to a first aspect of the present invention includes a cylindrical main body having openings at both ends, a tube plate attached to at least one end of the main body, and the main body so as to cover the tube plate. And a channel having a permeate vapor outlet, and a cantilever type separation membrane in which the opening ends of a plurality of tubular separation membrane bodies whose ends are sealed are attached to the tube plate. The membrane module in which the body group is formed is characterized in that the main body is inclined and a liquid storage mechanism is provided in the lower part thereof.

  According to a second aspect of the present invention, in the cylindrical membrane module according to the present invention, the liquid storage mechanism includes a liquid storage part and a liquid discharge valve, and the liquid level of the liquid storage part is within a predetermined range. It is characterized by performing.

  According to a third aspect of the present invention, in the cylindrical membrane module according to the present invention, the liquid reservoir mechanism includes a liquid level detection sensor, a controller, and an automatic liquid discharge valve, and the liquid level of the liquid reservoir is within a predetermined range. It is characterized by automatic control to enter.

  As described above, according to the present invention, the cylindrical main body having openings at both ends, the tube plate attached to at least one end of the main body, and the opening of the main body so as to cover the tube plate. And a channel having a permeate vapor outlet, and a cantilever type separation membrane body in which the open ends of a plurality of tubular separation membrane bodies whose ends are sealed are attached to the tube plate In the membrane module in which the group is formed, the main body is inclined and the liquid reservoir mechanism is provided at the lower part thereof, so that the membrane surface is covered with the condensate even if the supply steam (processed steam) is condensed in the membrane module. There is nothing.

  As a result, the function of the separation membrane does not deteriorate due to the membrane surface being covered with the condensate, and the separation performance of the membrane module can be maintained for a long time. This is because the membrane surface is hardly covered with the condensate, and the effective membrane surface is ensured as designed.

  Further, the cylindrical membrane module according to the second aspect of the present invention can be manufactured at a low cost with a simple configuration because the liquid storage mechanism includes a liquid storage section and a liquid discharge valve. Furthermore, since the liquid level is drained so that the liquid level in the liquid reservoir is within a predetermined range, the condensate serves as a seal, and the outflow of steam inside the membrane module or the inflow of air into the membrane module. Can be prevented.

  In the cylindrical membrane module according to the third aspect of the present invention, the liquid reservoir mechanism includes a liquid level detection sensor, a controller, and an automatic liquid discharge valve, and the liquid level of the liquid reservoir is within a predetermined range. Since the liquid is automatically drained to enter, there is no need for manpower, and this is particularly effective in long-term continuous operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an example of an apparatus for testing a membrane module according to the present invention.

  In FIG. 1, the mixture is vaporized by an evaporator (not shown) to become a mixture vapor a, and then supplied to the membrane module 1 to separate predetermined components. Thereafter, the passing steam b is condensed by the regenerator (condenser) 2 and stored in the passing liquid tank 3. On the other hand, the permeated vapor c that has passed through the membrane module 1 is condensed by the condenser 4 and stored in the permeate tank 5. Reference numeral 6 denotes a vacuum pump.

  An outline of the membrane module 1 is shown in FIG.

  As shown in FIG. 2, the membrane module 1 includes a main body 11, tube plates 12 a and 12 b, channels 13 a and 13 b, and a tubular separation membrane body 14.

  The main body 11 is a cylindrical main body 11 having openings at both ends, and is installed to be inclined. The main body 11 includes a steam inlet 15 for introducing supply steam (mixture steam) a on one side and a steam outlet 16 for discharging the passing steam b on the other side. Further, the main body 11 is provided with a large number of baffles 17 alternately inside, and the mixture vapor a introduced into the main body 11 is meandered along the baffle 17.

  A large number of tubular separation membrane bodies 14 are cantilevered on the tube plates 12a and 12b to form a separation membrane body group 14a. Explaining how to attach the tubular separation membrane body 14 to the tube plate 12b, as shown in FIG. 3, a tubular separation membrane body 14 having a sealed tip is used.

  A tube end member 18 is disposed on the opening end side of the tube-type separation membrane body 14. Further, the pipe end member 18 is provided with a tapered thread portion 19 on the outer periphery. The screw portion 19 is configured to be screwed to the screw portion 21 of the tube mounting hole 20 provided in the tube plate 12b.

  A heat-shrinkable tube 22 is welded to the outer periphery of the joint portion between the tube-type separation membrane body 14 and the tube end member 18 to maintain the sealing performance of the joint portion, and the tube-type separation membrane body 14 The open end is fixed to each tube plate 12a, 12b in a cantilever manner.

  In FIG. 2, the tube plates 12 a and 12 b are respectively covered with channels 13 a and 13 b that are attached to the openings of the main body 11. Each of the channels 13a and 13b is provided with a permeate vapor outlet 23.

  The greatest feature of the membrane module 1 of the present invention is that a liquid reservoir mechanism 30 is provided below the main body 11 installed in a horizontal shape with an inclination. The liquid storage mechanism 30 is connected to the main body 11 by a nozzle 25, is configured by a tank-type liquid storage section 24 and a liquid discharge valve 26, and is further connected to a liquid discharge pipe 27.

  Further, as a form of the membrane module to which the liquid storage mechanism 30 is applied, as shown in FIG. 4, a membrane module in which the separation membrane group 14a is installed only on one side of the main body 11, and as shown in FIG. There is a membrane module in which the separation membrane body group 14a is installed so as to overlap with each other, and a membrane module in which the separation membrane body group 14a is installed on the upper portion of the vertical body 11 as shown in FIG.

  Furthermore, as an aspect of the liquid storage mechanism 30, as shown in FIG. 7, the liquid storage section 24 can be directly connected by providing outlets for the mixture vapor a and the passing steam b on the side surface of the main body 11 with a horizontal inclination. The main body 11 may be connected.

  Here, as the separation membrane, a zeolite membrane deposited after supporting a seed crystal on a porous support, that is, an A-type zeolite membrane described in JP-A-8-318141, JP-A-8-257301. The Y-type zeolite membrane described in JP-A No. 8-318141 and the NaX-type zeolite membrane described in JP-A-8-318141 are desirable.

  Examples of the fluid to be separated in the present invention include water and alcohols such as methanol, ethanol, and propanol, ketones such as acetone and methyl ethyl ketone, and organic substances such as halogenated hydrocarbons such as carbon tetrachloride and tritaroloethylene. be able to. Furthermore, the fluid to be separated in the present invention is a mixture containing two or more organic substances as described above.

  Next, the operation of this membrane module will be described with reference to FIG.

  Now, when the mixture steam a is introduced into the main body 11 from the steam inlet 15, the mixture steam a becomes isothermal and flows toward the steam outlet 16 while meandering along the baffle 17. In the meantime, the specific component selectively permeates through the separation membrane (zeolite membrane) and becomes permeate vapor c and is discharged from the permeate vapor outlet 23 of the channels 13a and 13b.

  The concentrated steam b concentrated while flowing along the separation membrane body 14 is discharged from the steam outlet 16 of the main body 11. Then, it is condensed by a condenser (not shown) and collected as a product in a product tank (not shown).

  In this process, a part of the mixed vapor a flowing along the surface of the separation membrane (zeolite membrane) is condensed due to heat loss. The condensate d is stored in the condensate reservoir 24 through the nozzle 25.

  The condensate d stored in the condensate reservoir 24 is appropriately discharged to the outside by opening the liquid discharge valve 26, but the discharge amount so that the condensate d always accumulates in the condensate reservoir 24. Therefore, the steam a in the main body 11 does not flow out of the main body. For this reason, the pressure fluctuation in the main body 11 can be prevented, and a stable operation can be performed over a long period of time.

  Here, as shown in FIG. 8, a liquid level inspection sensor 28 and a control unit 29 are provided in the liquid storage part 24 of the liquid storage mechanism 30, and the liquid discharge valve is an automatic liquid discharge valve 26a. Liquid discharge operation can be automated. That is, since any liquid level can always be maintained automatically, it is particularly effective in continuous operation over a long period of time.

(Example)
Next, “Table 1” and “Table 2” show examples of dehydration operation of an ethanol aqueous solution using the membrane module of the present invention.

  Here, the examples are the operation results by the membrane module of the present invention, that is, the membrane module having the liquid reservoir mechanism, and the comparative examples are the operation results by the conventional membrane module not having the liquid reservoir mechanism. is there.

“Table 1” shows the dehydration operation of an aqueous solution having an ethanol concentration of 83.7 (wt%).
In this case, when the ethanol concentration in the product was compared, it was 96.5 (wt%) in the example of the present invention, whereas it was 95.0 (wt%) in the comparative example.

  That is, according to the present invention, it was proved that the amount of moisture permeation was increased, and as a result, high-purity ethanol was obtained.

Moreover, when the recovery rate of ethanol was determined by the following calculation formula (1), the comparative example was 98.5%, while the example of the present invention was 99.7%.
Ethanol recovery rate (%) = {1− (ethanol flow rate in permeate) ÷ (ethanol flow rate in feed solution)} × 100 (1)

  “Table 2” shows the dehydration operation of an aqueous solution having an ethanol concentration of 93.4 (wt%).

  In this case, when the ethanol concentration in the product was compared, it was 99.3 (wt%) in the example of the present invention, whereas it was 98.1 (wt%) in the comparative example. In this case, in particular, since the water concentration in the product can be reduced to 1 (wt%) or less, it was proved that the ethanol purification ability can be exhibited.

  Further, when the ethanol recovery rate was determined by the above-mentioned calculation formula (1), the comparative example was 99.4%, whereas the example of the present invention was 99.8%.

It is a schematic block diagram of mixed vapor separation using a membrane module. It is sectional drawing of the membrane module concerning this invention. It is sectional drawing of the separation membrane body with which the tube sheet was mounted | worn. It is sectional drawing of the 2nd example of the membrane module concerning this invention. It is sectional drawing of the 3rd example of the membrane module concerning this invention. It is sectional drawing of the 4th example of the membrane module concerning this invention. It is sectional drawing of the 5th example of the membrane module concerning this invention. It is a schematic block diagram which shows the form of the automatic control of the membrane module concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Main body 12a, 12b Tube plate 13a, 13b Channel 14 Separation membrane body 14a Separation membrane body group 24 Liquid reservoir part 25 Nozzle 26 Liquid discharge valve 26a Automatic liquid discharge valve 27 Liquid discharge pipe 28 Liquid level detection sensor 29 Control part 30 Liquid reservoir Mechanism a Mixture vapor b Passing vapor c Permeated vapor d Condensate

Claims (3)

A cylindrical main body having openings at both ends, a tube plate attached to at least one end of the main body, and a channel attached to the opening of the main body so as to cover the tube plate and having a permeate vapor outlet Further, in the membrane module in which the open ends of a plurality of tubular separation membrane bodies whose ends are sealed are attached to the tube plate to form a cantilever type separation membrane body group, the main body is inclined, A cylindrical membrane module characterized in that a liquid reservoir mechanism is provided in the lower part thereof. 2. The cylindrical membrane module according to claim 1, wherein the liquid storage mechanism is constituted by a liquid storage part and a liquid discharge valve, and drains the liquid so that the liquid level in the liquid storage part falls within a predetermined range. . The liquid reservoir mechanism has a liquid level detection sensor, a control unit, and an automatic liquid discharge valve, and automatically controls the liquid level of the liquid reservoir to be within a predetermined range. Cylindrical membrane module.

Images