Method for recovering and recycling oil from grease trap

Abstract

To provide a recycling method enabling easy cleaning of sludge having a large content of oil generated in a grease trap and ensuring effective utilization of an oil-absorbing material produced in the grease trap that has been disposed of as industrial waste.SOLUTION: The present invention provides a method for recovering and recycling oil from a grease trap. The method comprises recovering, from a business site 10 with a grease trap 1 installed, a sheet-shaped oil-adsorbing material 2 that is disposed in the grease trap 1 and has adsorbed oil contained in wastewater, the oil-adsorbing material being formed by accumulating polypropylene fibers containing polypropylene nanofibers, transporting the recovered material to a treatment facility 30, and extracting, at the treatment facility 30, oil adsorbed by the oil-adsorbing material 2 to produce a regenerated fuel and / or a regenerated oil.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for recovering and recycling oil from a grease trap. [Background technology]

[0002] Restaurants and other businesses that use large amounts of oil install grease traps to meet wastewater standards based on the Sewerage Act and the Water Pollution Control Act, and take measures to prevent oil from flowing into the sewer. The oil-containing sludge that accumulates in the grease traps is periodically collected by specialized companies as industrial waste, and after undergoing appropriate chemical treatment, it is incinerated, landfilled, or other disposal methods.

[0003] Also known is a method of removing oil from wastewater by placing an oil adsorbent inside a grease trap (see, for example, Patent Documents 1 and 2). This oil adsorbent is also disposed of as industrial waste, just like sludge. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-277657 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-164867 Summary of the Invention [Problem to be solved by the invention]

[0005] It is conceivable to recover and recycle the oil contained in the sludge that accumulates in grease traps, but sludge contains not only oil but also water and food residues, and extracting only the reusable oil from the sludge would require many processes and expensive equipment, making this unrealistic.

[0006] Another option is to recover and recycle oil from the oil absorbents placed inside the grease trap. However, like sludge, common oil absorbents such as cotton and pulp absorb not only oil but also water, so in order to extract the oil from the absorbent, it is necessary to separate the water from the oil. Furthermore, when the oil absorbent absorbs water, the amount of oil that can be absorbed decreases, making it difficult to extract a sufficient amount of oil.

[0007] Furthermore, in order to recover oil from oil adsorbents, it is necessary to collect the oil-adsorbent materials from businesses where grease traps are installed and transport them to a treatment facility. However, general oil adsorbents have a low capacity to retain adsorbed oil, and oil leaks from the adsorbents during transportation, which makes transportation difficult and reduces the amount of oil that can be recovered from the adsorbents at the treatment facility.

[0008] For this reason, oil absorbents installed in grease traps are generally recognized as non-recyclable, and are instead collected by specialized companies as industrial waste.

[0009] Under these circumstances, the object of the present invention is to provide a recycling method that makes it easy to clean the large amount of oil-containing sludge generated in grease traps and that makes effective use of the oil adsorbents generated in grease traps that had previously been treated as industrial waste. [Means for solving the problem]

[0010] The method of recovering and recycling oil from a grease trap of the present invention (hereinafter sometimes referred to as the "method of the present invention") is a method of recovering and recycling oil from a grease trap, which involves recovering, from a business establishment where a grease trap is installed, a sheet-like oil sorbent made of an accumulation of polypropylene fibers including polypropylene nanofibers that has been placed in the grease trap and has absorbed oil in wastewater, transporting it to a treatment facility, extracting the oil absorbed by the oil sorbent at the treatment facility, and producing recycled fuel and / or recycled oil.

[0011] The sheet-shaped oil adsorbent material, which is made of an accumulation of polypropylene fibers including polypropylene nanofibers and is placed in a grease trap, repels water, adsorbs only oil without substantially adsorbing water, and can adsorb large amounts of oil. Furthermore, because it has excellent oil retention, it can prevent oil leakage during transportation and significantly improve oil recovery efficiency.

[0012] As with the method of the present invention, oil adsorbents that have adsorbed oil in wastewater can be collected from businesses where grease traps are installed, transported, and then used at a treatment facility to produce recycled fuels such as aviation fuel and biomass fuel, and recycled oils such as kerosene, heavy oil, and diesel from the oil adsorbed by the oil adsorbents.This makes it possible to treat oil adsorbents, which previously had to be discarded as industrial waste, as valuable materials.

[0013] In the method of the present invention, the oil sorbent preferably has an oil adsorption capacity of adsorbing oil at least 50 times its own weight, and an oil retention rate of 95% or more in a hanging test in which 500 cc of diesel is adsorbed and the sorbent is hung for 5 minutes. By using such an oil sorbent, the frequency of cleaning the grease trap can be reduced. Furthermore, the oil sorbent can be transported to a treatment facility with a larger amount of oil adsorbed, minimizing oil leakage during transportation, further improving the oil recovery rate.

[0014] In the method of the present invention, the oil adsorbent has a structure in which polypropylene fibers including polypropylene nanofibers having a fiber diameter of 100 nm or more and 500 nm or less and polypropylene microfibers having a fiber diameter of more than 1 μm and 20 μm or less are entangled, and has a basis weight of 150 g / m 2 ~300g / m 2 By using an oil adsorbent having such a structure, high oil adsorption capacity and oil retention rate can be achieved.

[0015] In the method of the present invention, it is preferable that a cleaning agent capable of inhibiting the growth of microorganisms is added to the grease trap.

[0016] In the method of the present invention, it is preferable to arrange three or more oil sorbents, each weighing 15 to 50 g per sheet (preferably 15 to 25 g per sheet), in the grease trap and recover the oil sorbents every 5 to 10 days. By using oil sorbents in the grease trap in this way, it is possible to recover oil sorbents that have adsorbed a larger amount of oil, and it is also easy to recover the oil-adsorbed oil sorbents.

[0017] In addition, in the method of the present invention, it is preferable to subject the fiber residue remaining after the oil has been extracted from the oil sorbent to an oil treatment for reuse, thereby making it possible to effectively utilize not only the adsorbed oil but also the oil sorbent itself. [Effects of the Invention]

[0018] According to the present invention, a recycling method is provided that makes it easy to clean the large amount of oil-containing sludge generated in grease traps and makes effective use of oil adsorbents generated in grease traps that had previously been treated as industrial waste. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram for explaining the method of the present invention. [Figure 2] 1 is an example of a flow diagram of the method of the present invention. [Figure 3] This is an example of a grease trap installed at a business facility. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to Figures 1 to 3. However, the description of the constituent elements described below is one example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. In this specification, when the expression "to" is used, it is used as an expression including the numerical value or physical property value before and after it. In addition, common parts in Figures 1 to 3 may be assigned the same reference numerals and their description may be omitted.

[0021] Fig. 1 is a diagram for explaining the method of the present invention, and Fig. 2 is an example of a flow chart of the method of the present invention.

[0022] As shown in Figure 1, the method of the present invention is carried out by business establishments 10 that have installed grease traps 1 in which sheet-like oil adsorbents 2 made of an accumulation of polypropylene fibers including polypropylene nanofibers are placed, a transportation means 20 that collects the oil adsorbents 2 that have been placed in the grease traps 1 and have adsorbed oil from each business establishment 10 and transports them to a treatment facility 30, and a treatment facility 30 that extracts the oil adsorbed by the oil adsorbents 2 and produces recycled fuel and / or recycled oil.

[0023] As shown in Figure 2, in the method of the present invention, first, at a business facility 10, step S1 is carried out in which oil sorbents 2 are floated in a grease trap to remove oil from the wastewater, and the oil sorbents 2 are collected at regular intervals and temporarily stored. Next, step S2 is carried out in which the oil sorbents 2 that have adsorbed the oil in the wastewater are collected from the business facility 10 and transported by transport means 20 to a treatment facility 30, and step S3 is carried out in the treatment facility 30 in which the oil adsorbed by the oil sorbents 2 is extracted and recycled fuel and / or recycled oil is produced.

[0024] (Process S1) The business establishment 10 is a business establishment, such as a restaurant, where a grease trap 1 is installed. For example, FIG. 3 shows an example of a grease trap installed in the business establishment 10. The grease trap 1 shown in FIG. 3 is composed of three tanks, a first tank 11 to a third tank 13, separated by partitions 14 and 15. The first tank 11 receives food waste, such as leftover food and vegetable scraps, and is equipped with a basket B for collecting the food waste. The first tank 11 is a solid separation tank that separates solids from wastewater by collecting the food waste in the basket B and allowing sludge to settle. The second tank 12 is a tank adjacent to the downstream side of the first tank 11 and is an grease separation tank that blocks grease floating in the wastewater from the first tank 11. The third tank 13 is a tank adjacent to the downstream side of the second tank 12. The wastewater collected in the third tank 13 is discharged into the sewer via a trap pipe T that takes water from the middle layer.

[0025] At the facility 10, oil is removed from wastewater by floating sheet-like oil sorbents 2, composed of polypropylene fibers including polypropylene nanofibers, in the second tank 12 of the grease trap 1. The oil sorbents 2 are replaced periodically. The oil sorbents 2 are sheet-like sorbents composed of polypropylene fibers including polypropylene nanofibers, such as polypropylene sheets formed by melt-blown processes. The oil sorbents 2 are made of 100% polypropylene, which not only absorbs oil without absorbing water but also offers high safety. The oil sorbents 2 adsorb oil in wastewater, surfactants used in detergents, and scum. Installing the oil sorbents in this manner prevents oil from adhering to and accumulating on the peripheral walls of the second tank 12, facilitating the cleaning of large amounts of oily sludge generated in the grease trap at the facility 10. Furthermore, the sludge accumulated in the grease trap 1 does not contain oil, reducing sludge treatment costs.

[0026] The grease trap 1 needs to be cleaned periodically, and the oil adsorbent 2 is replaced when the grease trap 1 is cleaned. The oil adsorbent 2 collected from the grease trap 1 and having adsorbed the oil is placed in a plastic bag 3 or the like and temporarily stored at the business facility 10.

[0027] For example, at a business facility 10, three to six oil sorbents 2, each weighing 15 to 25 g, are placed in a grease trap 1 with a capacity of 70 to 300 L. The grease trap 1 is cleaned and the oil sorbents 2 are replaced every five to ten days, and the oil sorbents 2 are temporarily stored in bags 3. Depending on the capacity of the grease trap 1, the oil sorbents 2 are floated in the second tank 12 of the grease trap 1, or in the second tank 12 and the third tank 13. In this case, it is preferable to place the oil sorbents 2 without gaps throughout the second tank 12. To achieve this, some of the oil sorbents 2 may be placed overlapping each other. In this way, using multiple oil sorbents 2 makes it easier to place the oil sorbents 2 without gaps throughout the second tank 12, and each oil sorbent 2 does not become too heavy after absorbing oil, reducing the workload when replacing them without reducing the oil recovery rate. On the other hand, if a large oil adsorbent is used, the oil adsorbent will become heavy after absorbing oil, which increases the workload when replacing it.

[0028] The oil adsorbent 2 preferably has a structure in which polypropylene fibers, including polypropylene nanofibers having a fiber diameter of 100 nm or more and 500 nm or less, and polypropylene microfibers having a fiber diameter of more than 1 μm and 20 μm or less, are entangled, and has a basis weight of 150 g / m 2 ~300g / m 2 In this way, by creating a structure in which fibers of different diameters, including nanofibers, are intricately intertwined, it is possible to absorb only oil without substantially absorbing water. Furthermore, animal oils tend to coagulate easily and may be discharged in a solidified state in running water, but by creating a structure in which fibers of different diameters, including nanofibers, are intricately intertwined, it is possible to firmly adsorb animal oils both in a solidified state and when they are floating on water.

[0029] Furthermore, it is preferable that the oil sorbent 2 has an oil adsorption capacity of adsorbing oil up to 50 times or more its own weight (for example, 50 to 60 times its own weight), and that in a hanging test in which 500 cc of diesel is adsorbed and the material is hung for 5 minutes, the oil retention rate is 95% or more (more preferably 98% or more, and even more preferably 99% or more). The use of such an oil sorbent reduces the need for cleaning grease traps at the business establishment 10 and prevents oil from leaking from the oil sorbent while it is collected and temporarily stored, reducing the workload of employees at the business establishment 10 and facilitating transportation to and handling at the treatment facility 30.

[0030] In addition, a purifying agent (not shown) capable of suppressing microbial growth is added to the second tank 12. This suppresses microbial growth in the grease trap 1 and inhibits pipe clogging and biofilm formation, thereby reducing cleaning time and the labor required for cleaning. For example, the purifying agent added to the second tank 12 may contain charcoal, high-carbon ceramic, enzymes, ore powder, mineral powder, etc. In addition to suppressing microbial growth, such a purifying agent can also reduce odors and decompose oil. Using the oil adsorbent 2 in combination with the purifying agent can further improve the effectiveness of removing oil from the wastewater. This purifying agent is sprayed inside the second tank 12, but it may also be contained in a bag-shaped net and installed by hanging it on a partition wall of the second tank 12.

[0031] In particular, when collecting oil adsorbents 2 from establishments 10 equipped with grease traps 1, such as restaurants that use a lot of animal oils such as lard and beef tallow, it is preferable to add a purifying agent to the grease trap 1. Animal oils are prone to forming biofilms and coagulating, so there is a risk that they will not be adsorbed by the oil adsorbent, but adding a purifying agent breaks down the animal oil, suppressing the formation of biofilms and coagulation, and making it easier for the oil adsorbent to adsorb.

[0032] The grease trap installed at the business facility 10 is not limited to one with three water tanks, but may have four or more tanks. The amount of oil sorbents 2 used is selected appropriately according to the capacity of the grease trap. If the grease trap has a large capacity and the discharged wastewater contains a large amount of oil, seven or more oil sorbents 2 (e.g., 7 to 15 sheets) may be used. If the amount of oil discharged during the period until the oil sorbents 2 are replaced (e.g., every 5 to 10 days) is XL, 15 to 25 g per sheet of oil sorbents 2 having a structure in which polypropylene fibers containing polypropylene nanofibers with a fiber diameter of 100 nm to 500 nm and polypropylene microfibers with a fiber diameter of 1 μm to 20 μm are entangled can be used by floating X sheets of oil sorbents 2 on the grease trap 1. This allows for efficient adsorption (removal) of oil from the wastewater, and each oil sorbent 2 does not become too heavy even after absorbing oil, reducing the workload during replacement.

[0033] (Process S2) The transport means 20 is, for example, a vehicle such as a truck. The vehicle collects the oil adsorbents 2 that have adsorbed oil and are temporarily stored in plastic bags 3 or the like at the business operator 10, and transports them to a treatment facility 30.

[0034] (Process S3) The treatment facility 30 is a facility that extracts the oil absorbed by the oil sorbents 2 collected from the business establishment 10 and produces recycled fuel and / or recycled oil. For example, at the treatment facility 30, the oil sorbents are crushed as appropriate, and then the oil is extracted and separated from the oil sorbents 2 using pressure or centrifugation. The extracted oil is then pre-treated as appropriate, transferred to a distillation column, fractionated, and recovered for use as aviation fuel, kerosene, heavy oil, light oil, biomass fuel, etc. Furthermore, the fiber residue remaining after the oil has been extracted from the oil sorbents 2 is subjected to an oilification process and recovered as kerosene or heavy oil, which can then be reused. This allows the oil sorbents to be effectively used without being disposed of. [Industrial Applicability]

[0035] According to the method for recycling oil from a grease trap of the present invention, oil that has previously been disposed of as waste can be effectively reused as aviation fuel, kerosene, heavy oil, light oil, biomass fuel, etc. [Explanation of symbols]

[0036] 1. Grease trap 10 offices 11 Tank 1 12 2nd tank 13 Tank 3 14,15 Bulkhead 2. Adsorbent 20 Means of transportation 3 bags 30 Treatment Facilities B Basket T-trap tube

Claims

1. From a business establishment where a grease trap is installed, a sheet-like oil adsorbent material comprising an accumulation of polypropylene fibers including polypropylene nanofibers, which is placed in the grease trap and adsorbs oil in the wastewater, is collected and transported to a treatment facility; A method for recovering and recycling oil from a grease trap, comprising extracting the oil adsorbed by the sorbent at the treatment facility and producing recycled fuel and / or recycled oil.

2. 10. The method of claim 1, wherein the sorbent material is made of 100% polypropylene.

3. 3. The method according to claim 1 or 2, wherein the oil adsorbent has an oil adsorption capacity of adsorbing oil 50 times or more its own weight, and has an oil retention rate of 95% or more in a hanging test in which 500 cc of diesel fuel is adsorbed and the material is hung for 5 minutes.

4. The oil adsorbent has a structure in which polypropylene fibers including polypropylene nanofibers having a fiber diameter of 100 nm or more and 500 nm or less and polypropylene microfibers having a fiber diameter of more than 1 μm and 20 μm or less are entangled, and has a basis weight of 150 g / m 2 ~300g / m 2 The method according to claim 1 or 2, wherein

5. 3. The method according to claim 1 or 2, wherein the grease trap is charged with a cleaning agent capable of inhibiting the growth of microorganisms.

6. 3. The method according to claim 1 or 2, wherein three or more sheets of the oil adsorbent, each sheet weighing 15 to 50 g, are arranged in the grease trap, and the oil adsorbents are recovered every 5 to 10 days.

7. 3. The method according to claim 1, wherein the fiber residue remaining after the oil has been removed from the oil adsorbent is subjected to an oil treatment and reused.

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