JPS6022906A - Washing method of porous membrane - Google Patents

Abstract

PURPOSE:To recover the filtration capacity by backwashing with a compressed gas in a separating and removing process of a wax component by filtering oil and fat contg. the wax with a porous membrane. CONSTITUTION:The oil and fat contg. wax is sent into a module M by a supply pump P1 from an original liquid supply tank A. The filtration pressure is regulated to 0.5-3kg/cm<2>, for example. When a filtration velocity is decreased to 50% of the initial velocity, the process is changed over to backwashing. A gas (N2) is supplied into the inside of the module M from a gas supply port E by closing the pump P1 and valves 1 and 2, and opening valves 3 and 5. The gas releases and flies the wax deposited on the outer wall, and the wax component is obtained from a discharge port C through the valve 3. Although a gas at ordinary or warmed temp. can be used in ordinary filtration, the wax is effectively and completely dissolved by passing heated dewaxed oil through the inside of the membrane when the filtration velocity begins to decrease.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering a decrease in filtration ability that occurs when a porous membrane is used as a t-F material. More specifically, it relates to a method for recovering the decrease in the filtration ability of the P material that occurs when edible oil t is filtered to remove wax content.

The object of the present invention is to deposit wax with the wax! The object of the present invention is to complete a method for quickly and easily completely recovering the reduced filtration ability caused by RK.

Currently, in the refining process of vegetable liquid oil, the waxes contained therein are removed by filtration with a glycote filter using a filter aid. More specifically, vegetable crude oil is rapidly or slowly cooled to precipitate wax, and then pre-coated with a filter aid and treated in a filter press to obtain dewaxed oil. The layer is easily clogged with wax, and the filter leaf plate must be cleaned several times a day, and the P additive containing a large amount of wax and neutral oil must be disposed of, resulting in further interruptions. When restarting the filtering operation, a new precoat layer must be created and filtration must be started, resulting in considerable time and loss of new filter aid.

Even in the porous M (hereinafter referred to as "exchange") dewaxing process, wax accumulation on the membrane surface during the dewaxing process significantly reduces the filtration rate, so the membrane surface must be cleaned or restored at regular intervals. Some means must be taken to improve the permeation flow rate. Wax adhering or depositing on the membrane surface causes winkling, etc., and the viscosity decreases at low temperatures, which significantly deteriorates the separation and filtration of the wax from neutral oil.

The present inventors conducted studies on a method for quickly and easily recovering the above-mentioned decrease in p-filtration capacity, and found that wax crystallized at low temperatures adheres to the membrane surface during filtration 8. This wax layer forms a layer with a certain thickness, but by lashing or backwashing (in the case of oil, using oil or gas from the permeate side to the raw liquid side), the membrane surface is similar to that at the initial stage of use. The present invention was completed based on the knowledge that the permeation flow rate can be restored.

That is, the present invention provides a method for fully recovering the offshore permeability of a porous membrane, which is characterized by performing backwashing with compressed gas in the process of filtering fats and oils containing wax through a porous membrane to separate and remove the wax. Furthermore, the present invention is a method characterized in that backwashing using compressed gas is performed in combination with backwashing using heated oil.

In the present invention, the gas or oil used for backwashing is
The temperature range that can melt the wax is desirable, above room temperature 8
0-100C is optimal. It goes without saying that even if the temperature of the gas or oil is not necessarily high (even room temperature), it plays an effective role in wax removal and blowing operations.

The inert gas used is generally crab gas, carbon dioxide gas, dry air, etc., which are the lowest and can be used in large quantities. When using oil, it is possible to use the filter at room temperature, but if it is heated to the melting temperature of the wax, a better backwashing effect can be obtained. When using all the heated oil, there is a flushing effect when the external pressure is exceeded and the internal pressure is backwashed.

Next, conditions during recovery (backwashing) will be described. When attempting to clean the membrane surface on which wax has accumulated so that the flow rate can be restored to its original level, the backwashing pressure of gas or liquid (oil) must be 0.5 to 0. 101g
/di or less is convenient.

When carrying out the process, the feed of the undiluted solution is stopped and the remaining undiluted solution inside the module is expelled through the special blowing piping.
The important point is to keep the wax in its original state without breaking it.

When most of the neutral oil has been blown out, the wax that has adhered to the membrane surface can be removed by applying reverse pressure from the permeate side to the non-permeate side using gas (N) or liquid (dewaxed oil). Alternatively, it is possible to remove impurities etc. 7. After that, the removed wax can be blown with gas or oil from the other blow pipe to clean it. By repeating this operation, it will last for a long time. The entire dewaxing operation can be continued without human intervention.The quality of the dewaxed oil produced by this method is better than that of the conventional method.

The effects of the method of the present invention are as follows.

■You can expect an improvement in yield. The current law for sunflower oil is
It cannot be recovered as pure wax, and the entire amount, including neutral oil, is discarded along with the filter aid. However, with the membrane de-lox method, there is less loss of neutral oil, and wax separation is much easier. Since it is easy to perform, it has a great effect on the production process.

■No need for filter aids, eliminating the cost of purchasing filter aids.

■The separated crude wax can be used in cosmetics, etc., opening the door to applications as high value-added products.

■All dewaxing work will be automated, and throughput will also be improved.

■The quality of dewaxed oil improves.

Embodiment 1 An explanatory diagram of tax evasion by the all-FFI method is shown in FIGS. 1 and 2. The structure was such that the stock solution was supplied from the outside of the module, and the F solution came out from the inside of the module, so that impurities such as wax would adhere to the outside of the module.

To describe an example of dewaxing sunflower oil, first, a sunflower stock solution (using bleached oil) that has been rapidly cooled to below 10C is supplied from the stock solution supply tank A to a module M (Jli
3j f 4 (expressed in a mathematical formula). At this time, only the supply side valve (1) and the F liquid outlet B valve (2) are set to J14, the others are fully closed, and the filtration pressure is 0.
．． P overwork is carried out at 5-5 kg / aI. After about 1 to 2 hours, the filtration rate drops to below the initial rate of 50 cm, so the membrane cleaning (backwashing) process is switched to the next one. At this time, supply pump P1, valve (1),
+2+ is closed, valves (31, (51) are opened, and gas (Nt) is injected into the module M from the gas supply port E.
The wax is extruded to the outside under a pressure of 2 to 3 kg to peel and scatter the wax adhering to the outer wall, and the wax is obtained from the discharge port C via the valve (3). Extraction time is approximately 2-3 minutes.

Next, the wax discharged between the outside of the module M and the housing is flowed from the valve (3) to the discharge port C side for 10 to 60 seconds by opening the loop (9). j After cleaning the root surface, return to the original process and pump P+'
fr: Use this to supply undiluted liquid and send oil from the cylinder (1) and restart offshore passage. A series of these two-cycle wheels,
Everything is automatically operated by sequence control. The above sequence mechanism is shown in Table 1.

When working for a long period of time or when filtering different types of oil, a backwash process using caloric dewaxed oil is added in case backwashing is insufficient. The method will be explained according to FIG. 2, and the method is the same as when using N gas. llI 1! f Heat dewaxing oil is pumped from G through pump Pz and knob (7), and the wax adhering to the membrane (or hollow fiber surface) is melted by heating to melt the wax (3). The wax is obtained from the v-outlet C through the entire system.In addition, the frequency of backwashing can be said to be 11 times less than that of gas backwashing. ) is nokurupu, 'o#
'i' is a circulation pipe for returning the entire feed stock solution to the stock solution supply tank A, and in FIG. 2, (6) and (8) are valves, and F is an outlet for the heated dewaxed oil.

Example 2 Case of internal pressure p filtration-external pressure backwashing by total filtration method All FIGS. 3 and 4 will be explained. The structure is such that all the liquid is supplied from the inside of the module, and when the internal pressure is applied, the p liquid comes out to the outside U.The structure is such that impurities such as wax adhere to the inside of the module. This is done by backwashing.

Similar to Example 1, an example of dewaxing sunflower oil will be described. First, a sunflower stock solution (using decolorized oil) that has been rapidly cooled to below 10C is sent from the stock solution supply tank A' to the module M' by a supply pump P'HK. At this time, only the supply side valve QO) and the F liquid outlet B' valve 01) are opened,
The others are fully closed, and the work is carried out at a filtration pressure of 0.5 to 5 kg/cIIt. After approximately 1 to 2 hours have elapsed, the p overspeed decreases to below the initial speed of 50 degrees, so the work is switched to membrane cleaning (backflow). At this time, the supply pump PI
% valve (II and circle are closed, valve (1'!J
, Q4I opens, gas (N, ) enters inside the module M' from the gas supply port E', and at a pressure of 2 to 5 yen, the feed stock solution accumulated in the module M' is completely vented from the discharge port C' from the harp A4. Alternatively, the liquid may be returned to the stock solution supply tank A' by opening the valve α and passing through the circulation bag D' completely.

At this time, the fc wax and impurities that adhere to the membrane surface are
It is desirable that only the neutral oil adhering to the inside of the tube be discharged, and if the adhering wax is subsequently removed by backwashing from the outside with gas or dewaxed oil, highly pure wax can be recovered. becomes. To discharge the wax, open the valve α, introduce gas (Nt) from the gas supply port H through the valve asn-, remove all the wax adhering to the inner wall, and pump the wax with N2 pressure. The following procedure is performed in the same manner as in Example 1. In addition, the fourth
In the diagram a/H heating oil tank p/ means pump, aa
, (l?)ti valve.

Normally, backwashing can be done using room temperature or warmed gas when passing offshore, but when the p overrate begins to gradually decrease (once a day or once every two days), thermal desorption can be used. After the wax adhering to the inner surface of the hollow fibers is completely dissolved using wax oil, the re-purging operation is started. In this case, the number of washes, the time for one wash (timer), etc. are all automatically operated by sequence control.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams when performing external pressure filtration and internal pressure backwashing using the total filtration method. Figures 5 and 4 are explanatory diagrams when performing internal pressure filtration and external pressure backwashing using the total filtration method. It is a diagram. Figure 1 Figure 2 Figure 3 0 B'c' Figure 4 0

Claims (5)

[Claims] (1) A method for restoring the filtration ability of a porous membrane, which comprises performing backwashing with compressed gas in the step of filtering fats and oils containing wax through a porous membrane and separating and removing the four components. (2) The method according to claim 1, wherein the porous membrane is a hollow fiber membrane. (3) The method according to claim 1, wherein the porous IjIt membrane is tubular. (4) In the process of filtering fats and oils containing wax through a porous membrane to separate and remove wax, backwashing with compressed gas,
A method for restoring the filtration ability of a porous membrane, characterized in that it is carried out in combination with backflow using heated oil. (5) Claims in which the frequency of backwashing with compressed gas is greater than the frequency of backwashing with heated oil, and the interval between backwashing with compressed gas is shorter than the interval between backwashing with heated oil. The method described in Section 4.