JP2005238006A - Oil desorption method from oil adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for separating and recovering oil by which incineration treatment or the like of an adsorbent after adsorbing the oil is eliminated, recovery of an solvent used for removing oil adhering onto the adsorbent and effective utilization of recovered oil can be attained in the method for separating and recovering the oil from sewage water by using the adsorbent. <P>SOLUTION: Talc is added to the sewage water containing oil, then obtained mixture is agitated and thereby the oil is separated from the sewage water and is condensed by adhering the oil onto a surface of the talc. Then the oil adhered onto the talc is removed from the talc by being dissolved in an organic solvent and the talc from which the oil is separated is again utilized as the adsorbent of the oil. Further the oil contained in the organic solvent is separated and recovered and then is effectively utilized as fuel or the like and the organic solvent can be reutilized as the solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention recovers oil from sewage using talc as an adsorbent, cleans the oil adhering to talc with a solvent, or separates the oil from talc by heating, and recycles the separated talc as an adsorbent. The present invention relates to a method for desorbing oil from an agent.

  The sewage from food processing factories, meat processing factories, machining factories, etc. contains oil, and cannot be drained unless this oil is processed. As a method for separating oil from sewage, a separation method using a specific gravity difference between water and oil has been known for a long time. This method is a method in which sewage is put into a separation tank to separate the oil component. It is.

  The collected supernatant liquid contains oil and water, so it must be incinerated. However, incineration requires a lot of moisture, and fuel for auxiliary combustion is required. Moreover, it is difficult to separate the emulsion-like fine oil present in the sewage, and a small amount of oil may be contained in the treated water. Therefore, an activated carbon adsorption device, a pressure levitation device, or the like is employed as a method for efficiently separating the oil in the sewage. The activated carbon adsorption device is a method for adsorbing and removing oil in sewage with activated carbon. Since activated carbon is porous, it has a property of adsorbing a large amount of oil. In this method, when the adsorption amount of the oil content of the activated carbon becomes saturated, the activated carbon is replaced with new activated carbon and the oil component is adsorbed again. The activated carbon that has adsorbed the oil is taken out from the apparatus and mainly incinerated.

The pressure flotation device is a method of aggregating oil using a flocculant and separating it from sewage as a floc. The floc is taken out and incinerated. Japanese Patent Application Laid-Open No. 2003-290604 adds an organic solvent to sewage, dissolves the oil, recovers the organic solvent containing the oil from the sewage, and then separates the oil and the organic solvent to recover the oil and the organic solvent. Has been proposed.
JP 2003-290604 A

  In the activated carbon adsorption method, when the activated carbon adsorbs oil, the activated carbon is taken out and transported to an incineration plant, where it is incinerated, which causes complicated work. Furthermore, in order to continuously separate and remove the oil component, it is necessary to replenish the activated carbon, and there are problems such as generation of expenses due to the purchase of new activated carbon and filling of the activated carbon into the apparatus.

  Further, in the case of pressurized flotation, a flocculant is added to collect the oil as floc, and the floc needs to be collected and transported to an incineration plant and incinerated in the same manner as activated carbon. This floc contains a lot of moisture, and a fuel for auxiliary combustion is required for the combustion process. Furthermore, in a method in which an organic solvent is added to sewage to dissolve oil, and the oil and organic solvent are separated from the organic solvent containing oil, sewage generally has a small amount of oil, and excess organic solvent is required to increase the oil recovery rate. There are problems such as being necessary.

  An object of this invention is to provide the method of isolate | separating an oil component efficiently from the waste water containing an oil component. The oil described here is a solid or liquid oily substance that separates from water.

  In order to achieve the above object, in the present invention, talc is put into sewage containing oil, the oil is attached to the talc, the talc is taken out from the sewage, and the oil is removed from the talc using an organic solvent. And the talc is reused as an oil adsorbent.

  Moreover, in this invention, the said talc which isolate | separated the oil component is again put into the said waste water, and it is characterized by the above-mentioned.

  Furthermore, the present invention is characterized in that talc is separated from the sewage by filtration or heating.

  Furthermore, the present invention is characterized in that when the oil component is separated from the talc, the oil component adhering to the talc is desorbed using the organic solvent.

  In the present invention, by adding talc to the sewage containing oil, the oil can be easily separated from the sewage by attaching the oil to the surface of the talc, so that the oil attached to the talc dissolves using an organic solvent. The talc that has been separated from the talc and separated from the oil can be reused again as an adsorbent for the oil.

In the present invention, it is also possible to separate and recover the oil contained in the organic solvent from the organic solvent, effectively use the oil for fuel and the like, and reuse the separated organic solvent. In addition, talc which is an adsorbent is naturally produced as a kind of talc and phyllic mineral, and its composition formula is Mg [(OH) ₂ Si ₄ O ₁₀ ]. This talc is chemically and thermally stable and can withstand long-term use in the treatment of sewage containing impurities.

  The method for desorbing oil from the oil adsorbent according to the present invention uses talc to adsorb and concentrate the oil in the sewage, add an organic solvent to the talc adsorbed with this oil, dissolve the oil, The talc from which is removed is reused. Therefore, the work of transporting and processing the talc to which oil has adhered to an incinerator or the like becomes unnecessary. Moreover, since a small amount of oil in the sewage is concentrated by using talc, the oil can be efficiently dissolved with a small amount of solvent.

  The oil contained in the organic solvent can be separated by a method such as distillation, the oil can be used for fuel, etc., and the organic solvent can be recovered and reused. Solvent replenishment can be eliminated. Furthermore, there is an effect that dioxins contained in the sewage can be removed with high efficiency.

  FIG. 1 is a block diagram illustrating a system for separating and collecting oil from sewage according to the present invention. The procedure for recovering oil from sewage will be described below.

  Put sewage containing oil into the treatment tank. Next, the powder talc is put into the treatment tank, and the talc is mixed with the sewage by stirring to adhere the oil contained in the sewage to the surface of the talc. The sewage containing talc is filtered by a suction method, and separated into talc and oil treated with oil. Talc with attached oil is washed with an organic solvent to dissolve and remove the oil attached to talc. The talc from which oil has been removed is dried and reused as recycled talc. By distilling the organic solvent containing the oil after washing, the organic solvent having a high vapor pressure can be separated from the oil, condensed, recovered, and reused as the solvent again. The recovered oil can be used as fuel.

  In the above-described cleaning step, although not shown, a method of heating with steam or the like and separating the oil adhering to talc is also effective.

  FIG. 2 is a characteristic diagram for explaining the amount of oil adsorbed when talc and water in other adsorbents do not coexist. The adsorption operation was performed according to JIS K5101. Fig. 2 shows the effect of particle size when talc is used as the adsorbent. As talc has fewer pores and smaller particle size, the apparent surface area per weight of talc increases, increasing the amount of adsorption. it is conceivable that. Therefore, it is desirable to use an oil adsorbent having a small particle size of 50 μm or less, preferably 20 μm or less. At the same time, the amount of oil adsorbed using aluminum hydroxide and calcium carbonate as the adsorbent was shown. It can be seen that talc adsorbs much oil as well as these adsorbents.

  FIG. 3 is a characteristic diagram for explaining the water adsorption amount of talc, silica gel, and molecular sieves. Silica gel was manufactured by Wako, Wakogel C-300, and molecular sieves were manufactured by Sigma Aldrich Japan, and molecular sieves 4A was used. Talc is less water adsorbed than other adsorbents, and this suggests that talc is hydrophobic, that is, has a strong lipophilicity, and therefore adsorbs much oil.

  FIG. 4 is a block diagram illustrating a test procedure for determining the amount of oil adsorbed using an adsorbent such as talc. FIG. 5 is a characteristic diagram illustrating the amount of oil adsorbed in the presence of water and specific test conditions when an adsorbent such as talc is used.

  A test procedure using talc will be described with reference to FIGS.

  After adding 5 ml of salad oil to 50 ml of water, add 2 g of fine talc and stir for 30 minutes. After stirring, suction filtration is performed using a filter paper, and the oil is adhered to talc and filtered treated water. Thereafter, talc to which oil has adhered is washed using 80% methanol and 20% hexane as a solvent, and the oil that has adhered to talc is dissolved and desorbed.

  The filtrate is a solvent containing oil, and the oil is separated by drying the filtrate and removing the solvent. Thereafter, a marker for measuring the amount of oil in the oil was measured by GC-MS analysis, and the amount of oil adsorbed was determined, indicating a high oil content recovery performance of 96.81% to 99.40%. Although 80% methanol + 20% hexane was used as a solvent for washing and removing oil from talc, the mixing ratio can be changed depending on the properties of the oil, and the mixing ratio of methanol and hexane is not particularly limited.

  At the same time, the results of a comparative test using aluminum hydroxide as an adsorbent are shown. Aluminum hydroxide adsorbed a large amount of oil in the absence of water, but the test could not be continued because the oil separated from the aluminum hydroxide in the presence of water. From this, it became clear that it could not be used as an adsorbent for separating oil in sewage.

  In addition, as a result of conducting an experiment for separating dioxins contained in oil, when dioxins were contained in 99 pg-TEQ / ml in the stock solution by adding talc, dioxins contained in filtered water were 0.8 pg- It was TEQ / ml and showed a high removal rate of 99.2%. That is, it can be seen that talc has the property of effectively removing dioxins.

  FIG. 6 is a characteristic diagram for explaining a repeated adsorption / desorption test when an adsorbent such as talc is used. The test proceeded according to the procedure shown in FIG.

  Silicon oil was used as the oil, and ethyl acetate was used as a cleaning solvent. The test is repeated three times using talc as an adsorbent. That is, talc adsorbed with oil is washed with a solvent, talc is regenerated and used again as an adsorbent for oil. The oil recovery rate during this period is 90% or more, which indicates that oil is recovered from talc with high efficiency. In addition, the loss of talc during this period was as small as about 0.3% at one repetition, and it was confirmed that the property of talc was not changed and was stable. As a result, talc can be reused as an oil adsorbent any number of times, and its adsorption characteristics are not significantly degraded.

  It can be used to separate and recover oil contained in sewage from food processing plants, meat processing plants, and machining plants. In addition, oil can be separated and recovered by introducing talc into oil isolated by an oil fence such as marine pollution.

It is a block diagram explaining the isolation | separation collection system of the oil from the sewage of this invention. It is a characteristic view explaining the oil adsorption amount when the water in the talc and other adsorbent of this invention does not coexist. It is a characteristic view which compares the water adsorption amount of talc, silica gel, and molecular sieves used for this invention. It is a block diagram explaining the test procedure which calculated | required the adsorption amount of the oil component using adsorption agents, such as talc of this invention. It is a characteristic view explaining the adsorption amount of oil in the presence of water and specific test conditions when using an adsorbent such as talc of the present invention. It is a characteristic figure explaining the repetition test of adsorption / desorption at the time of using adsorption agents, such as talc, of the present invention.

Claims (4)

  Add talc to sewage containing oil, attach the oil to talc, remove the talc from the sewage, separate the oil from the talc using an organic solvent, and reuse the talc as an oil adsorbent A method for desorbing oil from an oil adsorbent.   2. The method for desorbing oil from an oil adsorbent according to claim 1, wherein the talc from which oil has been separated is put into the sewage again.   The method for desorbing oil from an oil adsorbent according to claim 1, wherein the talc is separated from the sewage by filtration or heating. 2. The method for desorbing oil from an oil adsorbent according to claim 1, wherein the oil adhering to the talc is desorbed using the organic solvent when separating the oil from the talc.

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