JPS63221805A - Filter - Google Patents

Abstract

PURPOSE:To maintain the feeding speed to respective modules uniformly and filter the liquid to be treated efficiently and at a low cost by providing bypass piping connected directly to the inlet pipe of the first module and feeding respective filter modules connected in series with the liquid to be treated. CONSTITUTION:Respective filter modules are divided into unit modules 1 consisting of one to a plurality of modules, and a bypass piping 3 for feeding the respective units with the fresh liquid to be treated, connected directly with the inlet pipe of the first module, is provided. The liquid to be treated passes through the filter modules, and is filtered and concentrated to reduce the liquid volume, and the liquid volume to compensate said reduction is replenished from said bypass pipings 3 to make the feeding speed to respective units within the range of 70-100% of the feeding speed to the first filter module unit for the purpose of preventing the feeding speed from decreasing and also preventing the concentration of the liquid to be treated from increasing unnecessarily.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to the recovery of valuable substances such as proteins, sugars, and amino acids, and the purification of relatively highly concentrated solutions that can be used in fields such as food, fermentation, and industrial wastewater treatment. , relates to a filtration device using a selective permeable membrane filtration module used for concentration.

[Prior art]

At present, when a highly concentrated liquid to be treated is filtered, purified and concentrated using a selective permeable membrane, the following problems arise, making it difficult to put the process into practical use.

That is, (i) As the P value of the liquid to be treated increases, the amount of permeated liquid (hereinafter referred to as FltlX) generally decreases in an exponential manner.

(11) With filtration, the amount of the liquid to be treated decreases and the flow rate decreases, resulting in significant contamination of the membrane surface and FIU
X decreases.

(iii) When filtration is performed using a plurality of filtration modules, the dirt on the membrane surface tends to be nonuniform among the filtration modules, making the task of replacing filtration modules complicated and increasing running costs.

Various methods have been proposed to solve these problems, but none of them can be said to be sufficient.

For example, it is known that filtration modules are arranged in the shape of a Christmas tree. (Japanese Unexamined Patent Publication No. 53-14961, etc.) The Christmas tree type is a device that maintains the supply flow rate of the liquid to be treated by gradually decreasing the number of filtration modules arranged in parallel as the liquid to be treated decreases due to filtration. Although there are many practical examples, the number of filtration modules can only be an integer value, so the number of filtration modules used is large.

There are ways to improve this method by adjusting the arrangement of the filtration modules and the membrane area and performance.
94017, JP-A-53-78653, etc.)
In either case, the piping and arrangement become complicated, resulting in an increase in initial cost, and furthermore, there arises the problem that it becomes difficult to respond flexibly to lot variations in the liquid to be treated. In these methods, since it is necessary to have a very large membrane area to carry out filtration treatment in one bath, batch method filtration apparatuses are also known in which the liquid to be treated is repeatedly passed through the same filtration module for filtration. In this batch method filtration device, it is easy to control the flow rate of the liquid to be treated and the membrane area can be reduced, but as mentioned above, as the concentration of the liquid to be treated increases, F
There is a problem that +ux decreases and a large amount of filtration time is required.

To solve these problems, a device that shortens the filtration time by arranging a large number of filtration modules in parallel could be considered, but this would require a pump with a large discharge volume to transport the liquid to be treated, which would increase the initial cost. .

Another known method is a semi-batch filtration device in which several stages of batch filtration devices are arranged in series for filtration. This is a method in which the concentration of the liquid to be treated is increased in stages, and the membrane area is small and the flow rate of the liquid to be treated can be maintained at a high level. The liquid to be treated with a higher concentration is always batched, so the Fl
It is not ideal in terms of uX, and it is extremely difficult to control as it requires careful management of communication between stages and adjustment of pressure and flow rate at each stage.

In addition, various devices and filtration methods that combine these methods have been proposed (for example, JP-A-53-58974 and JP-A-56-67583), but all of them are more complex, resulting in increased initial costs and management problems. The current situation is that complexity is unavoidable.

[Purpose of the invention]

The present invention was developed as a result of intensive studies aimed at creating an apparatus for filtering, refining, or filtering and concentrating a liquid to be treated with high efficiency and at low cost. With the knowledge that this could be achieved by keeping the supply flow rate as uniform as possible, further research was conducted and the result was completed.

[Structure of the invention]

In the present invention, when performing filtration purification or filtration concentration of a liquid to be treated using a selective permeable membrane, each filtration module connected in series is divided into units consisting of one to a plurality of filtration modules, and the liquid to be treated is transferred to each unit's filtration module. Supply the liquid to be treated to the filtration module of the first unit to the liquid to be treated piping of each filtration module so that the supply rate is in the range of 70 to 100% of the rate of supply to the first filtration module. The present invention relates to a filtration device having a bypass pipe directly connected to a pipe.

The type of filtration module used in the present invention is not particularly limited, and modules using any type of membrane such as hollow type, tubular type, spiral type, etc. can be used as long as they use a selectively permeable membrane in cross flow. Available.

If the filtration modules are connected in series, the liquid to be treated that has passed through the filtration module will be filtered and concentrated compared to the liquid to be treated that is supplied to the first filtration module, and the amount of liquid filtered in the filtration module will be However, the supply speed of the liquid to be treated decreases, and the concentration also increases.

By replenishing the first liquid to be treated by bypass piping from the piping that supplies the liquid to the first filtration module in an amount commensurate with this reduction, the supply rate can be prevented from decreasing, and at the same time unnecessary S degree The increase can also be mitigated. The supply rate of the liquid to be treated is set to be in the range of 70 to 100%, preferably 90 to 100%, of the rate of supply to the first filtration module for all filtration modules. If the supply rate of the liquid to be treated to each filtration module is less than 70% of the supply rate to the first filtration module, the membrane surface linear velocity will be insufficient and the concentration will become high, making it impossible to improve the filtration efficiency. If it exceeds 100%, the surface linear velocity of the membrane becomes too high, and although efficiency is partially achieved, the proportion of the liquid to be treated that does not pass through the filtration module increases, resulting in a decrease in the throughput of the liquid to be treated as a whole.

In the apparatus of the present invention, it is desirable to increase the rate of supply of the liquid to be treated to the first filtration module so that the amount of liquid to be treated that is replenished midway through the system is less than 100%. Further, by using a valve attached to the bypass piping to adjust the supply rate of these liquids to be treated, adjustment of these supply rates can be made relatively easy. In order to avoid complicating the piping, instead of initially supplying the liquid to be treated to all of the filtration modules in each unit connected in series, it is possible to increase the effect by supplying only one part of the filtration modules. can.

No special measures are required for supplying the liquid to be treated.

Since the liquid that has passed through the filtration module has a pressure slightly lower than the pressure of the liquid that is supplied to the filtration module due to pressure loss, only piping and a simple pulp operation are required. In particular, even if a pump is used for this purpose, the power consumption is low and running costs do not increase.

〔Effect of the invention〕

The device of the present invention (a) can increase filtration efficiency without requiring complicated controls, piping, or combinations of filtration modules; Therefore, the number of filtration membrane modules required is small in any one-pass, batch, or semi-batch format.

(b) By adjusting midway replenishment of the liquid to be treated, it is possible to flexibly deal with variations in the concentration and amount of the supplied liquid to be treated. Particularly when a large number of them are operated in parallel, such as in a Christmas tree type, it is possible to prevent waste from occurring.

(c) Supplying the liquid to be treated, which has a low viscosity and has not passed through the filtration module, to the concentrated liquid that has passed through the filtration module and has a high viscosity, will reduce the viscosity, which is advantageous in terms of pressure drop and temperature control. becomes.

Moreover, it is effective when the liquid to be treated easily forms a gel layer on the membrane surface, and can be expected to be used in food, wastewater treatment, etc.

(d) There is a method to increase filtration efficiency by adding coagulants such as hydrogen peroxide and iron salts to the liquid to be treated, but the optimal amount to add varies depending on the concentration, and adding too much may clog the filtration module. .

In the apparatus of the present invention, the liquid to be treated can be added in an appropriate amount from the midway through the supply line, so there is no need to worry about clogging the filtration module.

〔Example〕

Example 1 (i) The length of the filtration module used was 1 m, and the pipe diameter was 167! Seven I11 tubular membranes tied in parallel were used.

(11) Membrane performance A 5% by weight aqueous solution of sucrose was added at a water temperature of 20°C and a pressure of 20°C (
Kg/cri) and linear velocity of 1 (7?Z/SeC), the amount of liquid permeated through the filtration module is 7.
31/Trthr), and the rough sucrose conversion rate was 10 (%).

(iii) Liquid to be treated 40-45BX containing aminomelanoidin, sugar, etc., PH
A molasses aqueous solution containing 28% of 5,0, C0D was used. This liquid relatively easily formed a gel layer, and considerable coloring and adhesion were observed on the membrane surface after filtration operation.

(iv) Filtration conditions: Liquid temperature: 70 ± 3 (℃), supply rate of the liquid to be treated entering the first module unit: 1.0 (TrL/sec > (4
, 87 ft/hr), and the inlet pressure was set to 20 (Kg/cIi).
). In addition, for the filtration module that introduces the liquid to be treated midway, the inlet flow rate is set to 1, 0 force g, os (m
/sec).

(V) Filtration device As shown in Figure 1, 30 filtration modules (30Tr
An improved one-pass filtration device according to the invention was used, in which the liquid to be treated was replenished every L>.

Table 1 shows the results of measuring the concentration and liquid volume at the outlet while changing the length of the device.

Comparative Example 1 Table 1 summarizes the results of measurements made by changing the length of the device in the same manner as in Example 1 for a conventional one-pass filtration device that does not supply the liquid to be treated midway.

As described above, it can be seen that when the apparatus of the present invention is used, although the concentration ratio (the amount of liquid to be treated/the amount of liquid at the outlet) is low, a large amount of the liquid to be treated can be supplied, and as a result, the amount of permeated liquid is large.

Example 2 As shown in FIG. 4, the apparatus of the present invention was connected in a Christmas tree shape as a filtration system for concentrating the liquid to be treated fed at 24 (TIi/hr) three times. The operating conditions were the same as in Example 1: an inlet linear velocity of 1.0 (m/sec) and an inlet pressure of 20 (Kg/cIi), and the liquid to be treated was supplied every 30 m.

The first stage uses four devices of the present invention connected in series of 240 m in parallel, the second stage uses three devices of 630 m in parallel, the third stage uses two devices of 360 m in parallel, and the second stage uses two devices of 360 m in parallel. The fourth stage is 6.16 on the side where the devices of the present invention are connected in series for 360 m.
(TIi/hr) and 3.58 (TIi/hr) respectively to the 420m conventional method connected in series,
A concentrated solution was obtained. The concentration ratio of each stage outlet is 1.25.1.6
It was 6.2.46.3.00. The total number of filtration modules required was 4200 (4200 m>).

Comparative Example 2 The same as in Example 2, a conventional Christmas tree type filtration system was used in which the liquid to be treated, supplied at 24 m/hr, was concentrated three times. The operating conditions are the same as in Comparative Example 1. The first stage had five filtration modules connected in series with 240 m in parallel, the second stage had four 330 m modules, the third stage had three 540 m modules, and the fourth stage had two 270 m modules. The outlet concentration ratio of each stage is 1.24.1.64.
It was 2.49.3.0. The total number of filtration modules required was 4680 (4680 m>).

When operating at an inlet flow velocity of 1.0 (m/sec) or less, this is the minimum number of traditional Christmas trees.
Table Filtration effect in one pass device a) Unit (m/hr
) b) Unit (TrL).

As described above, according to the present invention, the number of modules can be reduced by about 10% compared to the conventional Christmas tree format.

Example 3 As shown in Fig. 2, 30 filtration modules (30m>
Using a batch-type filtration apparatus according to the present invention, which replenishes the liquid to be treated every time, the operating conditions were the same as in Example 1, and the time required for concentration was measured.

Table 2 shows the results of concentrating 1Q of the liquid to be treated by changing the overall length of the apparatus.

Comparative Example 3 An experiment similar to Example 3 was conducted using a conventional batch filtration device that does not supply the liquid to be treated midway. Second result
They are summarized in the table.

Table 2 Required time for concentration in a batch device a) a) Unit (hrs) b) Calculation by measuring the permeate layer from the initial raw treated liquid volume of 10 grams Example 4 As shown in Figure 3, 30 filtration modules ( 30m)
Using the improved semi-batch apparatus according to the present invention, which replenishes the liquid to be treated every time, the concentration ratio of the concentrated liquid and the concentrated liquid in an equilibrium state when the amount of liquid supplied to the apparatus is set to 960 (i/hr) The amount was measured. The operating conditions were the same as in Example 1, and Table 3 shows the results of increasing the total length of the device.

Comparative Example 4 The same experiment as in Example 4 was conducted except that a conventional semi-batch filtration device was used in which the liquid to be treated was not replenished midway. The results are shown in Table 3.

Table 3 Concentration effect in the semi-batch device a) Unit (1/hr) b) Calculated from the ratio of the amount of permeate to the amount of liquid supplied to the semi-batch device, 960 (J!/hr) Example 5 According to the present invention In the improved one-bath filtration device, the total length is 6.
When filtered at 30 m under the same conditions as Example 1, the concentration ratio was 1.
55, outlet flow velocity 0.98 m, /5eC (4,68 m/h
r). In other words, if the liquid to be treated is replenished in the middle of the process, the entire apparatus is taken up, and the rl is 5 m/sec.
(7.2 m/hr).

Comparative Example 5 Since it is not preferable for the apparatus to operate for a long time at an artificial flow rate of 1.5 m and /SeC, filtration was performed using two conventional one-pass filters in parallel. The inlet flow rate of each filtration module is 0.75 m/sec (3,6 TrL/hr).

To set the exit concentration ratio to 1.55 as in Example 5,
The total length of one piece is 660m (the entire equipment is 1320Tr1
．． ) was necessary. As described above, it can be seen that the present invention not only requires fewer membranes, but also has the advantage of being able to flexibly respond to changes in the supply amount of the liquid to be treated.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 illustrate improved one-bath, batch, and semi-batch type filtration devices, respectively, in accordance with the present invention. 1 is a unit formed by connecting filtration modules in series, 2 is a liquid sending pump, 3 is a bypass pipe, 4 is a processing liquid tank, and the arrows in the figure indicate the flow of liquid. FIG. 4 shows the improved Christmas tree type filtration device described in Example 2. 5 replenishes the liquid to be treated midway 7
This is a device part of the present invention, and in terms of content, it means the one-pass type shown in FIG. 6 shows a conventional one-pass type.

Claims (4)

[Claims] (1) In an apparatus in which filtration modules consisting of selectively permeable membranes are arranged in series and the liquid to be treated is purified or concentrated by filtration, the filtration module is divided into units consisting of one or more units, and the liquid to be treated in each unit is A bypass pipe is installed in the supply piping that is directly connected to the pipe that supplies the liquid to be treated to the first filtration module unit, and the supply rate of the untreated liquid that enters the filtration module of each unit is adjusted to that of the liquid to be treated that enters the first filtration module unit. A filtration device characterized by supplying and filtering to each filtration module unit at a rate of 70 to 100% of the supply rate. (2) The filtration device according to claim 1, wherein the bypass piping is provided with a valve for adjusting the speed of the treated liquid supplied to each unit of filtration module. (3) The batch filtration device according to claim 1, wherein the unit filtration module consists of two units. (4) A semi-batch filtration device comprising several batch filtration devices arranged in series according to claim 3, each of which has two unit filtration modules.