JP2007283203A - Method and apparatus for treating water accompanying in oil field - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating the water accompanying in an oil field, each of which is suitable for removing a dissolved organic compound contained in the water accompanying in the oil field, which is obtained by separating/removing oil from the produced water associated with the crude oil produced by mining crude oil. <P>SOLUTION: The water accompanying in the oil field is brought into contact with zeolite having 100-200 molar ratio of SiO<SB>2</SB>/Al<SB>2</SB>O<SB>3</SB>to adsorb/remove the dissolved organic compound. It is preferable that the water accompanying in the oil field is brought into contact with Y-type zeolite having 170-200 molar ratio of SiO<SB>2</SB>/Al<SB>2</SB>O<SB>3</SB>and then brought into contact with ZSM-5 having 100-200 molar ratio of SiO<SB>2</SB>/Al<SB>2</SB>O<SB>3</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to processing of crude oil produced water produced when mining crude oil, and more particularly to a method and apparatus for treating oil field associated water after separating and removing oil from crude oil produced water.

  When mining crude oil, salinized crude oil output is discharged. This crude oil output is released into the ocean after separating the crude oil, but organic compounds are dissolved in the crude oil output, which may cause malodors or marine pollution. Is required to be processed.

  Patent Document 1 describes that there is an example in which oil is separated and removed from crude oil-produced water produced when mining from an offshore oil field, and microbial treatment is performed on water that has been separated into oil and water by causing emulsion breakage. ing.

  Patent Document 2 discloses a technique for removing oil and organic compounds contained in wastewater from power plants, sewage, or landfills, not from crude oil produced water. Oil absorption by sand filtration and COD by activated carbon Combining component adsorption is described.

Japanese Patent Laid-Open No. 2003-144805 Japanese Patent Application Laid-Open No. 2004-275484

  Many organic compounds such as acetic acid, propionic acid, and valeric acid are dissolved in the water after separating and removing the oil from the crude oil produced when the crude oil is mined (hereinafter referred to as oilfield associated water). ing. As described above, the activated carbon adsorption method is not necessarily appropriate as a method for adsorbing and removing many kinds of dissolved organic compounds.

  The objective of this invention is providing the processing method and processing apparatus suitable for removing the dissolved organic compound contained in oil field accompanying water.

In the present invention, the oil field associated water after separating and removing the crude oil from the crude oil produced during the mining of the crude oil is brought into contact with a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200. The purpose is to adsorb and remove dissolved organic compounds contained in the water accompanying the oil field.

  ADVANTAGE OF THE INVENTION According to this invention, the removal performance of the dissolved organic compound contained in oil field accompanying water can be improved.

  As an index for measuring the content of the dissolved organic compound, there is a biochemical oxygen demand (COD: Chemical Oxygen Demand). For this reason, dissolved organic compounds are generally referred to as COD components.

  This inventor examined whether various methods conventionally known as a processing method of an organic compound were suitable for a process of oil field accompanying water. As a result, the activated sludge treatment method is affected by chlorine and the treatment time is long. The sodium hypochlorite addition method, the hypochlorous acid generation method (electrolysis method) and the Fenton oxidation method reduce COD components. It turns out that the effect is poor. In addition, the vacuum concentration (distillation) method is difficult to separate unless it is a substance having a boiling point significantly different from that of water, and the treatment of the concentrated solution is a problem. In addition, it has been found that a large amount of activated carbon is required and the cost is increased.

In contrast, among the _zeolites, those the molar ratio of SiO 2 / _Al 2 _{O 3} is within the range of 100 to 200 have been found to be suitable as an adsorbent for COD components oilfield associated water. Zeolite is easy to regenerate.

Zeolite includes natural zeolite, synthetic zeolite, artificial zeolite and the like, and any of them can be used as long as the molar ratio of SiO ₂ / Al ₂ O ₃ is within the range of 100 to 200. Among them, ZSM-5, which is a kind of synthetic zeolite, is the most preferable adsorbent because it has particularly excellent adsorption characteristics of dissolved organic compounds in oilfield-associated water compared to other zeolites.

  A small amount of oil is emulsified and dispersed in the water accompanying the oil field, and contains very fine mud, sand, and other solid substances. Since these cause clogging of the adsorbent, it is desirable to remove the oilfield-associated water before bringing it into contact with the adsorbent. The oil field accompanying water also contains volatile organic compounds such as acetone. In order to enhance the adsorption performance of the dissolved organic compound by the adsorbent, it is desirable to remove this volatile organic compound in advance.

  It is also desirable to lower the molecular weight of dissolved organic compounds contained in the oilfield-associated water before contacting with the adsorbent. In particular, in the case of ZSM-5, the adsorption performance of the low molecular weight organic compound is excellent, so this method is preferable for enhancing the adsorption performance by ZSM-5.

The oil field associated water is first contacted with a Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 170-200, and then the SiO ₂ / Al ₂ O ₃ molar ratio is 100-200. Contacting ZSM-5 within the range is one of the preferred methods. Y-type zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ in the range of 170 to 200 is suitable for adsorbing organic compounds having a large molecular size, and ZSM-5 is a dissolved organic compound contained in water associated with oil fields. Although it has a good adsorption performance for all of these, it is particularly suitable for adsorbing organic compounds having a small molecular size. By bringing the oil field associated water first into contact with the Y-type zeolite and then contacting with ZSM-5, the dissolved organic compounds contained in the oil field associated water can be efficiently removed.

The oilfield-associated water treatment apparatus of the present invention is achieved by providing the oilfield-associated water treatment system with an adsorption device filled with zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200. . A preferable treatment apparatus includes an apparatus for removing solids contained in the oilfield associated water, an apparatus for removing volatile organic compounds contained in the oilfield associated water, and an oilfield associated water upstream of the adsorption apparatus. A pretreatment device comprising at least one device for reducing the molecular weight of dissolved organic compounds is provided. Also, the preferred processing apparatus includes a suction device that Y-type zeolite molar ratio of _SiO 2 / _Al 2 _{O 3} is within the range of 170 to 200 is filled in the upstream side of the processing system of oilfield produced water, downstream And an adsorption device filled with ZSM-5 having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200.

  Tables 1 and 2 show examples of major substances contained in the oilfield-associated water, their molecular formulas, and concentration analysis values. In Table 1 and Table 2, crude oil mining sites are different.

  Of the dissolved organic compounds listed in Tables 1 and 2, normal butyric acid (n-butyric acid) isobutyric acid (iso-butyric acid) and normal valeric acid (n-valeric acid) are particularly causative substances that are likely to generate malodors. It is said that.

The COD _Mn value of oil field associated water shown in Table 1 was 430 mg / L, and the COD _Mn value of oil field associated water shown in Table 2 was 1080 mg / L.

  Table 3 shows the molecular sizes of the main dissolved organic compounds contained in the oilfield-associated water.

The relationship between the adsorption properties to the molar ratio and the various carboxylic acids of _SiO 2 / _Al 2 _{O 3} of ZSM-5 which is a kind of synthetic zeolite shown in FIG. 1, the molar ratio of _SiO 2 / _Al 2 _{O 3} of Y-type zeolite FIG. 2 shows the relationship between the adsorption properties for various carboxylic acids. Moreover, the relationship between the mordenite and the adsorption characteristic with respect to various carboxylic acids is shown in FIG.

As apparent from FIGS. 1 to 3, the removal performance of the organic compound varies depending on the type of zeolite, and the removal performance of the organic compound varies depending on the molar ratio of SiO ₂ / Al ₂ O ₃ . What can be said from the results of FIGS. 1-3, the adsorption amount increases as the molar ratio of _SiO 2 / _Al 2 _{O 3} is greater at any zeolite, in particular the molar ratio of _SiO 2 / _Al 2 _{O 3} 100 to 200 This means that the effect appears remarkably in the range.

From FIG. 2, it can be seen that Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 170 to 200 adsorbs a large amount of an organic compound having a large molecular size. Further, FIG. 1 shows that ZSM-5 adsorbs many organic compounds having a small molecular size. From this, combining the Y-type zeolite in which the molar ratio of SiO ₂ / Al ₂ O ₃ is in the range of 170 to 200 and ZSM-5 in which the molar ratio of SiO ₂ / Al ₂ O ₃ is in the range of 100 to 200. Is valid.

  All the synthetic zeolites shown here have three-dimensional pores. However, the crystal structure of Y-type zeolite is slightly different from other ZSM-5 etc. in that it has a crystal structure in which pores with larger diameters exist at positions where the pores intersect. It is presumed that the adsorption performance of the organic compound having a large molecular size is excellent because the Y-type zeolite is adsorbed by the organic compound having a large molecular size in the pore having a large diameter.

FIG. 4 shows the relationship between the SiO ₂ / Al ₂ O ₃ molar ratio of ZSM-5, Y-type zeolite and mordenite and the acetic acid adsorption amount. Further, FIG. 5 shows the relationship between the SiO ₂ / Al ₂ O ₃ molar ratio of ZSM-5, Y-type zeolite and mordenite and the propionic acid adsorption amount. FIG. 6 shows the relationship between the SiO ₂ / Al ₂ O ₃ molar ratio of ZSM-5, Y-type zeolite and mordenite and the n-butyric acid adsorption amount. Among the three types of ZSM-5, Y-type zeolite and mordenite, the adsorption characteristics of ZSM-5 were the most excellent, followed by Y-type zeolite and mordenite.

  An embodiment of a processing apparatus according to the present invention is shown in FIG. 7 is a magnetic separation type rotary filtration device 4 that separates and removes oil and solids in oilfield-associated water and aeration treatment that aeration-treats filtered water 90 after removing oil and solids in oilfield-associated water. It comprises an apparatus 15, adsorption apparatuses 17, 18 that adsorb and remove dissolved COD components from the primary treated water, and an exhaust combustion apparatus 16.

A small amount of oil remains in the oilfield-associated water 1 after emulsification, and in addition, mud, sand, and other solid substances are mixed. Therefore, the oilfield-associated water 1 stored in the water tank 2 is sent to the coagulation tank 3, and a coagulant such as ferric sulfate or polyaluminum chloride, magnetite (Fe ₃ O ₄ ), γ-hematite (Fe ₂ O ₃ ), etc. Using the magnetic particles, the suspended matter is agglomerated to form a floc.

  The oilfield associated water containing floc is sent to the rotary filtration device 4 to separate the oil and floc from the oilfield associated water. The rotary filtration device 4 includes a rotary filtration membrane 5 and a rotary cylinder 6, and a magnetic field generator such as an electromagnet (not shown) is provided inside the rotary cylinder 6. Oil field-associated water is filtered by the rotary filtration membrane 5, and oil and floc 7 deposited on the rotary cylinder 6 are removed from the rotary cylinder 6 by spraying cleaning water or scraping off with a scraping plate, and the rotary filter 4 It is discharged outside. In the present invention, the solid matter removing device is not limited to a magnetic separation type rotary filtration device, but this magnetic separation type rotary filtration device is extremely suitable as a solid matter removal device in oilfield-associated water.

  The filtered water 90 from which the oil and floc are separated and removed is then sent to the aeration treatment device 15 to vaporize volatile organic compounds dissolved in the filtered water. Before the filtered water is sent to the adsorption device, the volatile organic substances are vaporized and removed in advance, whereby the COD component removal performance in the adsorption device can be enhanced.

The treated water 62 subjected to the aeration treatment is sent to the adsorption device 17 filled with the adsorbent 171 made of synthetic zeolite, and then sent to the adsorption device 18 filled with the adsorbent 181 made of synthetic zeolite. Here, the adsorption effect can be enhanced by removing the organic compound having a large molecular size by the adsorption device 17 and removing the organic compound having a small molecular size by the adsorption device 18. For this purpose, the adsorber 17 is filled with Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 170 to 200, and the adsorber 18 is filled with a SiO ₂ / Al ₂ O ₃ molar ratio. Is preferably filled with ZSM-5 in the range of 100-200.

  Note that the adsorption devices 17 and 18 may be filled with the same kind of zeolite, and the amount of adsorption can be increased as compared with the case where one adsorption device is provided. In this case, it is desirable to fill ZSM-5 as zeolite.

  The adsorption device 17 includes heating devices 20 and 21, and the adsorption device 18 includes a heating device 21. These heating devices may be electric furnaces or microwave induction heating furnaces. The heating devices 20 and 21 are used for heating and regenerating the adsorbent. In the heat regeneration of the adsorbent, water in the adsorber is drained by the drainage pipes 24 and 25, and the blowers 22 and 23 are operated to supply hot air of about 100 to 120 ° C. in the adsorber for several tens of minutes to about 1 hour. This can be done by blowing and drying the adsorbent. The blowing time varies depending on the height of the adsorption device and the blowing temperature, and is not limited to this. If the temperature of the air generated by the blowers 22 and 23 is 400 ° C. or higher, it can be used as an alternative to the heating devices 20 and 21. The atmosphere of hot air blown by the blower is preferably an atmospheric component.

  In FIG. 7, the suction devices 17 and 18 are provided with a blower pipe 28 for discharging the air blown by the blowers 22 and 23 to the outside, and a moisture meter 29 is installed in the blower pipe. It is desirable to measure the amount of water contained in the exhaust 91 from the blower with the moisture meter 29 and control the amount of air blown by the blower.

  In order to facilitate heating and regeneration of the adsorbent, it is desirable that at least one selected from Pt, Pd, Ru, Rh, Ni, Fe, Cu, Mn, and Co be supported on the adsorbent surface. These components act as combustion catalysts. The organic compound adsorbed on the zeolite is oxidized and burned by the catalyst component supported on the zeolite surface, the adsorbent is regenerated, and the adsorption performance is recovered. The regeneration temperature of the adsorbent when these combustion catalysts are supported is particularly preferably 400 to 500 ° C.

  In the present invention, it is desirable that at least two systems of adsorption devices are provided in parallel, and on the one hand, the regeneration process is performed on the other side during the adsorption process.

  The final treated water 40 that has passed through the adsorption device 18 is then discharged into the ocean or the like. It is preferable to measure the COD component of the final treated water 40 with the COD analyzer 263 and control conditions affecting the performance of the adsorbent, such as the adsorbent replacement timing.

  Further, it is desirable that the gas 30 generated in the adsorption device 18 by heating and regeneration of the adsorbent is provided with an exhaust combustion device 16 in the middle of the exhaust gas extraction pipe to burn and remove organic compounds contained in the gas.

  The shape of the adsorbent may be various shapes such as powder, granule, pellet, rod, fiber, plate, honeycomb, Raschig ring and the like. However, since it is desirable that the used adsorbent is regenerated and used repeatedly, it is preferable that the adsorbent be in the form of powder, granules, pellets, etc. that can be easily regenerated. Further, the adsorbent is preferably placed inside the adsorption device with a mesh or a perforated plate.

In the processing apparatus of FIG. 1, the adsorber 17 is filled with ZSM-5 having a SiO ₂ / Al ₂ O ₃ molar ratio of 100, and the adsorber 18 is filled with ZSM− having a SiO ₂ / Al ₂ O ₃ molar ratio of 200. No. 5 was filled and treated with water simulating oil field associated water shown in Table 1. The COD components collected at the sampling ports 260 and 261 and the COD _Mn value of the final treated water were measured. Here, COD _Mn value is used because time is required for quantification of multi-components, and COD _Mn value (emission standard value COD _Mn ≦ 120 mg / L) is used as a management index during actual operation. Because of the good thing.

As a result, the water collected at the sampling port 260 had a COD _Mn value of 600 mg / L, but the water collected at the sampling port 261 decreased to 200 mg / L, and the methanol concentration in the final treated water 40 was 10 mg / L. The COD _Mn value decreased to 50 mg / L.

Another embodiment of a processing apparatus according to the present invention is shown in FIG. In the processing apparatus of FIG. 8, three adsorption devices are arranged in series, and two systems are provided in parallel. The reason why the two systems are provided in parallel is that when the adsorption process is performed in one system, the regeneration process is performed on the other side so that the process can be performed continuously. Adsorbers 400 and 401 were filled with Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 200 suitable for adsorbing organic compounds having a relatively large molecular size such as butyric acid and valeric acid. ZSM-5 having a SiO ₂ / Al ₂ O ₃ molar ratio of 90 to 200 was used for the adsorption devices 402 and 403. The adsorbers 404 and 405 were filled with molecular sieve 4A having excellent methanol adsorption characteristics.

In the course of the adsorption treatment, water was sampled by sampling ports 406, 407, 408, and 409, and the COD _Mn value was analyzed. The COD concentration was measured by the oxygen demand (COD _Mn ) by potassium permanganate according to JIS K 0102 factory drainage test method. The concentration of carboxylic acids in the oil field-associated water was quantified by ion chromatography. Quantification of alcohols such as methanol and benzene hydrocarbons was performed by gas chromatography. Table 4 shows the analysis results of raw water, primary treated water, secondary treated water, and final treated water. According to this example, it was confirmed that the COD _Mn value of the final treated water is significantly lower than 120 mg / L, which is a general standard.

It is a characteristic diagram showing the relationship between the molar ratio and the acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of ZSM-5. It is a characteristic diagram showing the relationship between the molar ratio and the acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of Y-type zeolite. It is a characteristic diagram showing the relationship between the molar ratio and the acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of mordenite. It is a characteristic diagram showing the relationship between the molar ratio and the acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of various synthetic zeolites. It is a characteristic diagram showing the relationship between the molar ratio and propionic acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of various synthetic zeolites. It is a characteristic diagram showing the relationship between the molar ratio and the n- butyric acid adsorption amount of _SiO 2 / _Al 2 _{O 3} of various synthetic zeolites. It is a schematic block diagram of the oil field accompanying water processing apparatus by one Embodiment of this invention. It is the schematic block diagram which showed other embodiment of the processing apparatus by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Oil field accompanying water, 4 ... Rotary filtration apparatus, 15 ... Aeration processing apparatus, 16 ... Exhaust combustion apparatus, 17 ... Adsorption apparatus, 18 ... Adsorption apparatus, 171 ... Adsorbent, 181 ... Adsorbent.

Claims (8)

The oil field associated water after separating and removing the oil from the crude oil produced water produced by the mining of the crude oil is brought into contact with zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200, and the oil field A method for treating oilfield associated water, wherein dissolved organic compounds contained in associated water are adsorbed and removed.   2. The method for treating oilfield associated water according to claim 1, wherein ZSM-5 is used as the zeolite. In the method for treating oil field associated water after separating and removing oil from the crude oil produced by the extraction of crude oil, the oil field associated water is included in the treatment for removing solids suspended in the oil field associated water. After performing at least one of the treatment for removing the volatile organic compound and the treatment for lowering the molecular weight of the dissolved organic compound dissolved in the oil field accompanying water, the molar ratio of SiO ₂ / Al ₂ O ₃ is 100 A method for treating oilfield-associated water, wherein a dissolved organic compound is adsorbed and removed using a zeolite of ~ 200.   4. The method for treating oilfield associated water according to claim 3, wherein ZSM-5 is used as the zeolite. After contacting the oil field associated water after separating and removing the oil from the crude oil produced by the mining of crude oil with a Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 170-200 A process for treating oilfield-associated water, wherein dissolved organic compounds are adsorbed and removed by contacting with ZSM-5 having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200. An oil field associated water treatment apparatus after separating and removing oil from crude oil produced water produced by crude oil extraction, wherein the SiO ₂ / Al ₂ O ₃ molar ratio is 100 to 200 in the oil field associated water treatment system. An apparatus for treating oilfield-associated water, comprising an adsorption device filled with zeolite in the above range, wherein the organic compounds contained in the oilfield-associated water are adsorbed and removed. An oil field associated water treatment apparatus after separating and removing oil from crude oil produced by extraction of crude oil, the apparatus removing solids contained in the oil field associated water and included in the oil field associated water A pretreatment device comprising at least one of a device for removing volatile organic compounds and a device for reducing the molecular weight of dissolved organic compounds dissolved in the oil field accompanying water, and after being treated by the pretreatment device The oil field associated water is provided with an adsorbing device for adsorbing and removing dissolved organic compounds by contacting the oil field associated water with zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 100 to 200. Processing equipment. An oil field associated water treatment apparatus after separating and removing oil from crude oil produced water produced by crude oil extraction, wherein the molar ratio of SiO ₂ / Al ₂ O ₃ is upstream of the oil field associated water treatment system. Adsorption apparatus equipped with an adsorption device filled with Y-type zeolite in the range of 170 to 200 and filled with ZSM-5 in which the molar ratio of SiO ₂ / Al ₂ O ₃ is in the range of 100 to 200 on the downstream side An apparatus for treating oil field associated water characterized by comprising an apparatus.

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