RU2508150C2 - Method of cleaning oil product tank drainage waters and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to filters for removal of water, impurities and biological contaminants from oil products. Invention consists in cleaning drainage waters from impurities in centrifugal field by filtration in fluid flow directed against gravity force direction. It comprises cleaning of filter material from separated sediments of impurities by swirling flow of fluid by filtration in said fluid flow in direction aligned with that of gravity forces. Proposed device comprises casing with settler closed by perforated damping cover with at least one inlet, outlet and drain pipes and at least one coalescing filter. Said casing comprises unions for media interface level top and bottom transducers. Solid bottom with drain pipe with swirler is amounted on thrust ring above polymer coalescing filters inside said casing. False bottom is arranged above solid bottom at another thrust ring for drain pipe to pass there through and filter material to be secured thereto by clamp ring. Reflector is attached to solid bottom from below.

EFFECT: higher capacity, longer life.

9 cl, 2 dwg

Description

 The present invention relates to the filtration of drainage water in oil storage tanks, and more particularly, to filtering devices for purifying oil products from water, solids and bio-contaminants.

When storing petroleum products in tanks, the presence of commercial water above the minimum level provided by the design of the device for water drainage (about 25 mm from the bottom of the tank) is not allowed. At low temperatures, as necessary, drain the produced water from the tank, and flush the siphon valve with the stored oil and turn it to the side position. [Rules for the technical operation of oil depots approved by Order of the Ministry of Energy of the Russian Federation of June 19, 2003 No. 232, items 6.12-6.13]. The siphon valve is installed on the lower belt of the tank at a height of 350 mm from the bottom and serves for the periodic release from the reservoirs of produced water falling out of the flooded oil products. The displacement of produced water from the reservoir occurs due to the hydrostatic pressure of the liquid column when the siphon tube is turned to the lower position and the drain cock is ajar. In the inoperative state, the downpipe is turned upward and filled with oil product with the simultaneous displacement of residual produced water along with part of the oil product into the sewer. This ensures that the crane does not freeze in the winter [Zakozhurnikov Yu.A. Storage of oil, oil products and gas: a manual for SPO-Volgograd: Publishing House "In-Folio", 2010. - 432 p.].

In urgent cases, if necessary, the heating of highly viscous petroleum products (mainly heating oil in railway tanks and oil tankers) is allowed to heat them with “hot steam”.

In these cases, saturated water vapor is injected through the perforated pipes directly into the oil product and condenses, giving it the necessary heat. The watered oil product should subsequently be dehydrated. [The rules for the technical operation of oil depots, approved by Order of the Ministry of Energy of the Russian Federation of June 19, 2003 No. 232, p. 6.33]. For dehydration of petroleum products at petroleum product supply enterprises, it is necessary to have special equipment - batch tanks, vertical cylindrical tanks with a conical bottom, horizontal with intermediate tiers, with inclined partitions, vertical with conical plates, multi-tier with washing sludge, etc. [Rules for the technical operation of oil depots approved By order of the Ministry of Energy of the Russian Federation of June 19, 2003 No. 232, p.6.56]. The separated water at the same time merges into the industrial sewage system of the enterprise. The condensate from the steam heaters, which is of satisfactory quality, must be returned to the internal base of the condenser network. Contaminated condensate, the purification of which is impossible, should be cooled, followed by discharge into the production sewer. [Rules for the technical operation of oil depots approved by Order of the Ministry of Energy of the Russian Federation of June 19, 2003 N232, clause 6.38].

In refineries, drainage is carried out by opening a drainage valve into an industrial sewer. Drainage time and frequency are set by the factory.

Losses during the storage of petroleum products account for 2% of the storage volume, 17% of which falls on drainage.

The ingress of volatile petroleum products into industrial sewers worsens the air condition of the working area of enterprises and sometimes leads to fire and explosion.

It is known from the prior art to install filters containing polymer coalescent filter elements of the type "APRIS" from the filter material "APRISORB" on the discharge of produced water from fuel storage tanks. The low resistance of the filter material “APRISORB” allows you to install the filter in front of the pump and drain the produced water and purify the fuel by gravity due to the pressure of the liquid layer in the tank [V.M. Sedov, A.V. Gurko, N.A. Egorsheva, V.V. Serdyuk, L.A. Ashkinazi. // Scientific and technical seminar of the Council of chief mechanics of oil refining and petrochemical industry enterprises "Constructive and technological solutions to improve the efficiency of heat and mass transfer and other types of equipment for oil refining and petrochemical industries": Materials of the seminar, Moscow February 17-19, 2009 - M .: 2009. - p. 149-166.]. This technical solution is taken as a prototype.

The disadvantage of the prototype is a very small dirt capacity, which leads to the need for frequent regeneration of the filter. The dirt capacity of one filter element with a fuel capacity of 1 m ³ / h is 3 kg of mechanical impurities [Sedov VM, Serdyuk VV, Skobelev VN, Panov SB, Klimov AV, Ashkinazi L. BUT. New fuels with additives. // Proceedings of the IV International Scientific and Practical Conference, St. Petersburg, May 30 - June 2, 2006. - St. Petersburg: Academy of Applied Research, 2006. S.215-223.].

Depending on the conditions of storage, transportation and use, the content of mechanical impurities in the fuel can reach 200-300 g / t. Particle sizes are generally 10-40 microns. [Obelnitsky A.M. Fuel and lubricants: Textbook for technical colleges. - M .: Higher school, 1982. - 208 p.]. That is, the dirt capacity of one filter element is enough to clean only 15 tons of oil product, after which it will either have to be changed or regenerated. That is, the proposed design for cleaning large industrial containers for storing petroleum products is not suitable.

The problem to which the claimed invention is directed is to increase the dirt capacity and service life of the device for cleaning drainage water of oil product storage tanks, to prevent oil products from entering the sewers and, as a result, to reduce its fire and explosion hazard and to improve the environmental performance of the air in the working area of oil refineries and oil products supply, and oil products saving during storage.

The problem is solved due to the fact that the drainage water of the oil storage tanks is sequentially cleaned of mechanical impurities in a centrifugal field, by filtration through the filter material in a stream directed against the direction of gravity with simultaneous cleaning of the filter material from the separated sediment of mechanical impurities by a rotating stream of the liquid being cleaned, filtering through filter material in a stream coinciding with the direction of gravity, and filtering through a coalescent filter, after h its water, purified from oil and mechanical impurities, is discharged into an industrial sewer or used in the process, and oil separated from water and mechanical impurities is returned to the storage tank.

In the technical solutions known to us, the treatment of drainage water sequentially in a centrifugal field, by filtration through filter materials in the opposite direction and coinciding with the direction of gravity, washing from the filter material of the sediment of mechanical impurities by a rotating stream of the liquid being cleaned and filtering through coalescent materials is not described. Therefore, the proposed method meets the criterion of "novelty."

To implement the proposed method for the treatment of drainage water in oil storage tanks, the device shown in FIG. 1 has been developed.

A device for draining drainage water (FIG. 1) comprises a housing 1 with a pressure pump 30 and a gate regulating the width of the inlet slit 12 installed in front of the inlet fitting 2, which directs the cleaned flow of drainage water into the housing tangentially (FIG. 2), a nozzle for the outlet of the cleaned oil product 3 with a booster pump 31 for returning the refined oil product to the storage tank, nozzle 4 for the upper and 5 for the lower sensors of the medium separation level, a spherical bottom 6 with a nozzle for draining the water 7 separated from the oil products, and a removable cover 8 with fittings 9 for instrumentation and inert gas supply to check the tightness of the device. Inside the case is conditionally divided into five cameras. The first chamber, into which a tangentially directed flow of purified drainage water enters, is formed by a blind bottom 10 with a drain pipe 11 equipped with a swirl 13 mounted on a support ring 14, and a “false” bottom 15 mounted on a support ring 16 to which the pressure ring 17 filtering material is pressed 18. The second chamber is formed by a “false” bottom 15 and the cover of the device 8. The third chamber is formed by a blind bottom 10 with a drain pipe 11, under which a flow reflector 19 is attached to the bottom, and a “false” bottom 20 fixed to the support ring 21. A filtering material 23 is attached to the “false” bottom 20 of the pressure ring 22. The fourth chamber is formed by the “false” bottom 20 and the “false” bottom 24 mounted on the support ring 25. The fifth chamber is formed by the “false” bottom 24, in which the fittings 26 are fixed with coalescent polymer filter elements 27, and the spherical bottom of the device 6. Moreover, the distance from the top cover of the polymer filter element 27 to the lower edge of the outlet of the pure oil product 3 must be at least the diameter of the filter element 27. Above the coalescent polymer Filtered filters 27 have a blank bottom 10 with a drain pipe 11, and a false bottom 15 above it. Below the coalescent polymer filter elements 27, a damper 28 is mounted on the support ring 29. The damper 28 and the spherical bottom of the device 6 form a settling tank in which the separated purified water collects .

As filter material (pos. 18, 23), depending on the type of oil product being cleaned, the amount and composition of mechanical impurities, the required degree of purification, technical filter cloths, metal filter cloths or Johnson mesh are used. The filter material can be either the same or different, depending on the task. Typically, the filter material 18 is chosen more durable and wear-resistant, since it accounts for most of the mechanical impurities.

The pressure pump 30 provides a constant supply of drainage water to the treatment device at low hydrostatic pressure due to the small filling of the tank and the high resistance of the filters of the device when they are clogged with mechanical impurities.

The booster pump 31 provides the supply of refined oil to the storage tank with a small filling and low hydrostatic pressure.

The proposed device that implements the claimed method of cleaning the drainage water of oil storage tanks, operates as follows: drainage water containing oil and mechanical impurities flows through the inlet fitting 2, which is located tangentially to the filter housing 1, into the filter housing. An even greater swirling of the flow is facilitated by the pressure pump 30, which controls the width of the inlet slit of the gate 12, and the swirler 13 mounted on the drain pipe 11. The purified drainage water acquires a rotational movement, which, due to the action of centrifugal forces, separates the source material into heavy and light products. A heavy product (mechanical impurities) is discarded to the surface of the filter housing 1 and moves along it to the deaf bottom 10, where it accumulates. So the first stage of drainage water treatment is carried out. The liquid rises up and is filtered through the filter material 18 in the opposite direction to the direction of gravity, into the upper blind chamber, from where it enters the second layer of filter material 23 through the drain pipe 11. This is the second stage of the drainage water treatment. Since the filtered stream rotates, it flushes out a significant part of the mechanical impurities retained by the filter material 18. Contaminants break away from the filter material and accumulate on the deaf bottom 10. This helps to reduce the amount of contamination on the filter, lower its resistance and loss of pressure of the liquid flow on it. This significantly increases the dirt capacity of the device.

Before entering the second layer of the filter material, the flow of the cleaned liquid enters the reflector 19, hits and bounces off it, enters the deaf bottom 10 and only then enters the filter material 23. Changing the direction of flow of the liquid helps to isolate mechanical impurities from it. The drainage water filtered through the second layer of filter material 23 enters the filter coalescer 27. Thus, the third stage of drainage water treatment is carried out.

At the filter coalescer 27, additional treatment of drainage water from residues of small mechanical impurities and separation of drainage water into water that does not contain oil products, and oil products that do not contain water. Water accumulates on the spherical bottom of the filter 6, from where it is discharged into an industrial sewer or fed into the technological scheme of the enterprise. Water is drained automatically at the signal of two sensors of the separation of media 4 and 5. The upper sensor of the phase boundary 4 controls the upper water level, preventing it from rising above the damper 28 and mix with the refined oil product. The lower sensor of the phase boundary 5 does not allow the water level to fall below the beginning of the conical bottom of the filter 6, forms a hydraulic shutter and prevents oil from entering the industrial sewer.

The separated oil product is returned to the storage tank by means of a booster pump 31.

Such an organization of the drainage water treatment process can significantly increase the dirt capacity of the filter due to the increased volume of the chambers for collecting mechanical impurities, reduces the hydraulic resistance of the filter, prevents oil from entering the industrial sewer, which improves the environmental situation at the enterprise. In addition, the oil product separated from the drainage water is returned to the storage tank, which leads to a reduction in the loss of oil products.

In the technical solutions known to us, there are no devices that allow separating drainage water into an oil product that meets the requirements of GOST or TU into commercial products and water that meets the requirements for water to be drained into a city sewer or used for technological purposes, therefore, the proposed device meets the criterion "Inventive step".

At the Atyrau Refinery, the drainage discharge time is 10 minutes with a frequency of 2 hours until positive analyzes of the content of water and solids in kerosene are obtained. The average discharge of drainage water from the storage tanks of aviation brand TS kerosene is 5 m ³ per day. Assuming that only 4% of kerosene is lost, the daily savings will be 0.2 m ³ , and for the year with the planned 350 working days, the savings will be 70 m ³ .

To verify the effectiveness of the claimed method and the operability of the proposed installation, we selected a sample of produced water and bottom sediments, which are compiled during drainage, from a storage tank of diesel fuel L in accordance with GOST 305-82 with a volume of about 50 liters. Part of the sample was poured into a liter cylinder, and after 24 hours of sedimentation, the composition of the sample was visually determined. The sample contained 127 ml of sediment, 740 ml of water and 133 ml of diesel fuel. The fluid was carefully deconstructed into a separatory funnel and divided into water and diesel fuel. The content of mechanical impurities and oil products was determined in the extracted sample of produced water, drained into the drainage, and the content of mechanical impurities and water in the sample of diesel fuel was determined.

After cleaning the taken sample of bottom sediments by the claimed method in a laboratory setup, the separated water and diesel fuel were analyzed according to the same indicators. The results of the analyzes are given in table. 1 and 2.

Table 1 Analysis of diesel fuel before and after cleaning Diesel fuel sample The content of the fur. impurities according to GOST 6370-83,% Water content GOST 2477-65,% Before cleaning 1.3 0.23 After cleaning lack of lack of Requirements GOST 305-82 lack of lack of

As can be seen from the data given in table 1, diesel fuel fully complies with the requirements of GOST 305-82 and can be used for its intended purpose.

table 2 Analysis of produced water before and after treatment Commercial water sample The content of the fur. impurities,% The oil content according to PNDF14.1: 2.5-95, mg / DM ³ Before cleaning 2,3 2739 After cleaning 0.01 0.97 SanPiN requirement 2.1.4.1074-01 - 0.05 VUGP-97 requirement of the Ministry of Fuel and Energy of the Russian Federation - 1,5 / 25

From the data of table 2 it follows that the purified bottom water does not meet the requirements of SanPiN 2.1.4.1074-01 "Drinking water. Hygienic requirements for water quality of central drinking water supply systems. ” Obtaining drinking water from drainage water was not included in the task of this invention.

However, the obtained purified water complies with the “Departmental guidelines for the technical design of industrial water supply, sewerage and wastewater treatment of oil refining industry enterprises - VUGP-97” of the Ministry of Fuel and Energy of the Russian Federation in part:

2.5.1. Make-up water:

- petroleum products not more than 1.5 mg / l,

2.5.2. Recycled water during the return to circulation of biochemically treated effluents of the first sewage system and integrated treatment:

- petroleum products no more than 25 mg / l.

Those. water obtained after purification can be used as make-up and reverse water.

The purified bottom water also complies with the requirements of Order No. 201 of the Committee for Urban Management of the Administration of St. Petersburg "On Monitoring the Composition and Properties of Wastewater Disposed by Subscribers to the Sewerage Systems of St. Petersburg" of 5 mg / l as of November 25, 1996 .

In addition, purified bottled water also complies with the “Generalized indicators and the content of harmful chemicals that are most often found in natural waters in the Russian Federation, as well as substances of anthropogenic origin that are globally distributed” according to GOST 2874-82 “Drinking water. Hygienic requirements and quality control "in terms of petroleum products, in total, mg / l - 0.1. That is, purified water can be drained into natural bodies of water and the sea.

The claimed method of purification of drainage water using the proposed device made it possible to obtain water from drainage water contaminated with mechanical impurities and oil products suitable for discharge into natural reservoirs and use in technological processes, and an oil product that meets the requirements of GOST, which indicates the achievement of a new technical effect and compliance of the claimed solutions with the criterion of "inventive step".

Claims (9)

1. A method for cleaning drainage water of oil storage tanks by filtration through polymer coalescent filters, characterized in that the drainage water is pre-sequentially cleaned of mechanical impurities in a centrifugal field, by filtration through a filter material in a fluid stream directed against the direction of gravity, while simultaneously cleaning the filter material from the separated sediment of mechanical impurities by a rotating stream of the liquid being cleaned and filtering through the filter material in the liquid stream, coinciding with the direction of gravity. 2. Device for cleaning drainage water of oil storage tanks by filtration through polymer coalescence filters, comprising a housing with a sump closed by a perforated cover-damper, at least one inlet, outlet and drainage pipes and at least one filter coalescing filter, characterized in that the inlet nozzle directs the cleaned flow of drainage water into the housing tangentially, the housing further comprises a fitting for the upper and lower sensors of the level of the separation of the media inside of the housing above the polymer coalescence filters, a deaf bottom mounted on the support ring with a drain pipe equipped with a swirl is installed; a “false” bottom mounted on the other support ring is installed above the deaf bottom, through which the drain pipe passes and to which the filter material is attached to the deaf bottom by a pressure ring a reflector is attached to the bottom in front of the second “false” bottom mounted on the support ring above the polymer coalescent filters, to which the filter ring is attached truyuschy material. 3. A device for cleaning drainage water of oil storage tanks according to claim 2, characterized in that technical filter fabrics are used as filter material. 4. A device for cleaning drainage water of oil storage tanks according to claim 2, characterized in that metal filter cloths are used as filter material. 5. A device for cleaning drainage water of oil storage tanks according to claim 2, characterized in that a Johnson mesh is used as the filter material. 6. A device for cleaning drainage water of oil storage tanks according to claim 2, characterized in that the distance from the top cover of the coalescent filter element to the drain fitting of pure oil is at least the diameter of the filter element. 7. A device for treating drainage water of oil storage tanks according to claim 2, characterized in that it further comprises a pump on a drain line of drainage water from the tank to the device. 8. A device for cleaning the drainage water of oil storage tanks according to claim 2, characterized in that it further comprises a pump on the drain line of the purified oil into the storage tank. 9. A device for cleaning drainage water of oil storage tanks according to claim 2, characterized in that it further comprises a gate regulating the width of the entrance slit on the drain water inlet fitting into the device body.

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