RU2415175C2 - Procedure for filtration of transformer oil and device for its implementation - Google Patents

Abstract

FIELD: gas-and-oil producing industry.

SUBSTANCE: invention refers to procedure for filtration of chiefly transformer oil by its heating and supplying through filter from beneath upward. Also, oil is heated to temperature 70-150°C. The procedure of filtration is carried out as repeating cycles under a mode of velocity vacuum-pulse effect onto purified oil through a filter at duration of the pulse up to 5.0 sec and at pressure over 50 mm of m.c. with successive conditioning at residual vacuum during not more, than 10 min. Further, vacuum is dropped at the end of the cycle to atmospheric pressure and simultaneously the filter is regenerated by supplying dry heated air from top downward. The invention also refers to the device for implementation of the filtration procedure.

EFFECT: considerable acceleration of filtration procedure and regeneration of filter during purification of transformer oil.

6 cl, 3 dwg

Description

The invention relates to the purification of hydrocarbon oils, in particular to the filtering of insulating oils, and can be used in the petrochemical and energy fields of industrial production, including for the purification of transformer oils.

In their use in insulating and other oil mixtures, only a small amount of impurities, moisture, gases and aging products are formed that are formed both during use of the product and during its storage. This applies both to new oils, ready for use, and to oils used in high-voltage apparatuses, etc. An increase in the content of these substances above the permissible values is most often the result of inappropriate conditions for storing oils and handling them, and in insulating oil in high-voltage apparatuses, in addition, as a result of aging of oil-paper insulation, and this process accelerates over time.

Cleaning oil from mechanical particles is one of the important tasks.

A known method of filtering mineral oils and implementing its device, described in the author's certificate of the USSR No. 886351, M. C. B01D 17/10; C10G 33/06. Oil is cleaned by filtering it through layers of different fractional composition of the filter material. The disadvantage of this method is that the filter material must be periodically regenerated manually and partially updated in connection with the gradual leaching of the fine fraction of the filter layer.

Known filter separator containing a housing with a sump and several layers of coagulating porous filter material described in the USSR author's certificate No. 1287918, M.Kl. B01D 29/12, C10G 33/06.

The main disadvantage of such a filter is the impossibility of its regeneration at the place of use and, as a consequence, the need to completely replace the filter when it develops a certain working resource.

As a prototype, the method of purification of light oil products was selected, including their heating and feeding through the filter material from the bottom up, carried out with the preliminary complete impregnation of the filter material with heated pure dry oil and constant heating of the product to be purified during its filtration.

A tissue membrane and a capillary cleaner are used as filter material.

The installation that implements this method, selected as a prototype, contains a container with a horizontal perforated partition and a fabric membrane placed on it and a honeycomb divider with a capillary cleaner made of mutually perpendicular metal plates, a dirt collector connected by cones of a tapering surface to the outer perimeter of the perforated partition a heater, tanks for clean and dirty oil products and a system of supply pipelines.

In this method and device described in the patent of the Russian Federation No. 2084490, M. C. C10G 31/09, the liquid to be cleaned flows from the storage tank to the lower part of the filter housing (under the filter baffle), and the direction of fluid movement is opposite to the direction of gravity and the oil product is filtered due to the pressure drop created by the hydrostatic liquid column.

The disadvantages of the method and device is that before filtering contaminated oil, it is necessary to impregnate the filter material with dry and clean heated oil, and then feed the product to be cleaned onto the filter. In addition, after the dirt collector is completely filled with impurities, the cleaning process spontaneously stops, and in order to prepare for the start of the treatment plant in a new operation cycle, it is necessary to remove accumulated sludge from the dirt collector and re-impregnate the filter with dry and clean oil. In addition, from time to time it is necessary to manually completely replace the filter material due to the impossibility of its regeneration. All this requires additional material costs and significantly increases the total filtration time.

An object of the invention is the intensification of the process, as well as eliminating the disadvantages of the prototypes, creating a method and a device that implements it, eliminating additional work and providing filter regeneration in the filtering process.

The specified technical result is achieved by the fact that in the method of filtering transformer oil by heating it and supplying it from the bottom up, the oil is heated to a temperature of 70-150 ° C, and the filtering process is carried out in repeated cycles in the high-speed vacuum-pulsed action on the oil being cleaned through a filter with pulse duration up to 5.0 s at a pressure of not more than 50 mm Hg followed by exposure at a residual vacuum of no more than 10 minutes and then vacuuming at the end of the cycle to atmospheric pressure while regenerating the filter by supplying dried heated air from top to bottom.

The regeneration of the filter element can be enhanced by the fact that periodically at the end of the cycle, additional regeneration is carried out by supplying compressed air with a pressure of up to 4 atm. from top to bottom in the inner cavity of the filter element.

The indicated method is implemented in that a filtering device comprising a container with a filter and a dirt collector connected to containers for clean and dirty oil, a heater connected to a dirty oil tank and a supply pipe system additionally introduces a high-speed vacuum system connected to the container for clean oil, and a filter-dryer of atmospheric air connected to a filter container, the filter in which is made of filter material in the form of one or more filter elements, Commercially form of hollow cylinders, closed at the lower ends and mounted for pure oil flowing through the surface thereof, and their internal cavities in the upper part sealingly connected by pipelines with quick-acting valves to a vacuum system and filter drier air.

Each filter element may be made of porous ceramic, cermet or mesh material. For complete regeneration of the filter element, the device may include a system for the preparation and supply of compressed air connected through a pipeline and shut-off valves with a filter. To clean from heterogeneous impurities, the device may additionally contain one or more containers with filters of decreasing cross section and dirt collectors installed in series with the first container. In the proposed method and device for its implementation, the modes of thermal vacuum-pulse action during filtering of transformer oil intensify the filtering process due to shock pulse effect on the filter element, resulting in a significantly larger pressure difference when the oil passes through the filter element. Pulse discharge of vacuum to atmospheric pressure simultaneously provides regeneration of filter elements. For the complete regeneration of the cells and pores of the filter elements, it is possible to expose the filter element to compressed air with a pressure of up to 4 atm. In addition, excluded are additional operations present in the prototype (impregnation of the filter material with dry and clean heated oil, frequent replacement of the filter material, etc.). All this leads to a significant reduction in the filtering time of transformer oil.

The drawings schematically show:

- a device for filtering transformer oil (figure 1);

- the design of one of the options for the filter element (figure 2);

- installation of filtration with filters of "decreasing section" (figure 3).

A device for filtering transformer oil in thermal vacuum pulse conditions (Fig. 1) includes: a high-speed vacuum system 1 containing vacuum pumps, a receiver, a droplet eliminator, and an installation control panel (not shown in the drawing); capacity 2 for clean oil; high-speed vacuum valves: for pulsed supply of vacuum 3, dried atmospheric 4 and compressed air 5 to the working part of the filter; shut-off valves 6 for turning on (off) the supply of streams of purified (uncleaned) oil or dried atmospheric (compressed) air; pipelines 7 for the supply (removal) of oil, air, vacuum; capacity 8 for dirty oil; a heater 9 for heating the purified oil; sludge collector 10; station for the preparation and supply of compressed air 11; filter drier 12 for air inlet. The main working elements of the installation are: a container 13 with a filter 15 and a dirt collector 14. The filter 15 is made of one or more filter elements 16 having the form of hollow cylinders made of porous ceramics (cermets), closed with a “blank” lid on the lower end, and on the upper end - hermetically connected to the pipeline 7.

Figure 2 presents an embodiment of the filter element, where 17 are cylindrical walls, 18 is the lower cover, 19 is the upper cover of the filter element. The caps and the hollow cylinder are fastened by the tie rods 20 through the gaskets 21 and are a sealed design that allows oil to be filtered through the surface of the filter element.

The filtration unit (Fig. 3) may additionally include one or more containers 22 with filters of "decreasing cross-section" 15, installed in series with the first container 13 and serving for cleaning inhomogeneous impurities.

Installation for filtering transformer oil works as follows. Before cleaning, the contaminated oil is pre-heated to 70-150 ° C by a heater 9 in the dirty oil tank 8. At the same time, a high-speed vacuum system and a compressed air preparation station 11 are activated to provide the necessary discharge parameters (not more than 50 mm Hg) and overpressure (up to 4 atm.) respectively in the vacuum and air lines 7. When the vacuum system creates the appropriate pressure, the high-speed valve 3 is activated and under the influence of the pressure difference, creates known by the vacuum system between the inner cavity of the filter element 16 and its outer surface, the contaminated oil flows and is cleaned through the filter element in a pulsed mode with a pulse duration of up to 5.0 seconds. Then follows the exposure of the filter element and the product to be cleaned under vacuum for no more than 10 minutes at a steady residual pressure, accompanied by its further purification and flowing of the purified oil into a clean oil tank 2, and subsequent inlet into the internal cavity of the filter element 16 of dried air to atmospheric pressure through valve 4 , shut-off valves 6 and a filter drier 12. Pulsed portioned pumping of oil, as a result of its high-speed pulse evacuation and holding under vacuum, followed by vacuum discharge to atmospheric pressure makes up one filtering cycle of transformer oil. After 5-15 cycles of oil purification, a complete regeneration of the filter element can be carried out by supplying a return flow of dried air from the purification station to the filter and preparing compressed air 11 under a pressure of up to 4 atm. for dumping accumulated impurities from the receiving part of the filter (dirt collector 14) into the sludge collector 10. The device allows, if necessary, to fully automate the filtering process of transformer oil using high-speed vacuum valves and controlled shut-off valves with electric or pneumatic drive.

A sample of the inventive installation is made, passed the stage of pilot tests and showed high quality filtration of various grades of insulating oils, reducing the duration of the filtration process, reliability and ease of operation.

Pilot tests of the installation sample using porous ceramic material as a filter element showed high quality filtration. In particular, the analysis of moisture content in transformer oil, purified by the proposed method at temperatures of 90 and 130 ° C, showed a moisture content of less than 0.001% (less than 10 g per 1 ton). This moisture content meets the requirements for transformer oil, poured into high voltage oil transformers.

The method and device corresponding to the invention can also be used with high efficiency in filtering oil sludges, various liquids, emulsions and suspensions, ensuring their high-quality purification from mechanical impurities in various mixtures of oil products and liquids, for example, when dewatering sewage sludge from galvanic plants, and the presence of heterogeneous in composition or heterogeneous impurities, the greatest cleaning efficiency is achieved by stepwise filtration through filters of "decreasing section" in The dependence on the desired depth of treatment.

Claims (6)

1. A method of filtering predominantly transformer oil by heating it and supplying it from the bottom up through the filter, characterized in that the oil is heated to a temperature of 70-150 ° C, and the filtering process is carried out in repeated cycles in the high-speed vacuum-pulsed action on the oil being cleaned through a filter with pulse duration up to 5.0 s at a pressure of not more than 50 mm Hg followed by exposure at a residual vacuum of no more than 10 minutes and then vacuuming at the end of the cycle to atmospheric pressure, while regenerating the filter by supplying dried heated air from top to bottom. 2. The method according to claim 1, characterized in that periodically at the end of the cycle, an additional filter regeneration is carried out by supplying compressed air with a pressure of up to 4 atmospheres from top to bottom in the inner cavity of the filter element. 3. A device for filtering predominantly transformer oil, including a container with a filter and a dirt collector connected to containers for clean and dirty oil, a heater connected to a tank for dirty oil, and a supply pipe system, characterized in that it further comprises a high-speed vacuum system, connected to a container for clean oil, and a filter-dryer of atmospheric air connected to a container with a filter, the filter in which is made in the form of one or more filter elements s, having the form of hollow cylinders, closed from the bottom and installed with the possibility of the flow of clean oil through their surfaces, and their internal cavities in the upper part are hermetically connected by pipelines with quick valves with a vacuum system and a filter-dryer of atmospheric air. 4. The device according to claim 3, characterized in that the filter elements are made of porous ceramic, cermet or mesh material. 5. The device according to claim 3, characterized in that it further comprises a system for the preparation and supply of compressed air connected through a pipeline and shut-off valves with a filter. 6. The device according to claim 3, characterized in that it further comprises one or more containers with filters of "decreasing cross-section" and dirt collectors installed in series with the first for cleaning heterogeneous impurities.

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