RU2369750C1 - Turbomachine oil system cleaning method - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention refers to power engineering and can be used at thermal power stations with turbomachines of high unit power, which have branched oil systems of control, lubrication of bearings of turbine unit and sealings of generator shaft with large diametre of drain headers. The method can also be applied for cleaning any piping systems used for transporting the following: irrigation water - to clean them off sludge; hot delivery water - to remove corrosion products, as well as oil pipelines - to remove heavy oil sludge. In the turbomachine oil system cleaning method by means of alternate impulse circulation of oil pre-heated up to maximum allowable temperature and by injecting fine gas (air) therein, hot oil flow is supplied abruptly to the pipelines which are free from oil and have temperature not more than ambient temperature. At that, the flow, in order to increase thermoshock effect in the wall area, is directed through a flat convergent nozzle at a tangent to internal generatrix of cylindrical housing surface of the flushing volute injector coinciding with internal surface of the flushed pipeline; owing to which there formed is tornado-shaped oil-and-air swirl which, besides acts with centrifugal force on the layer of deposits bonded to the surface, and axial vector supplying compressed air through an annular splitting confusor provides the resultant (total) movement direction vector of rotary swirl with increased kinetic energy along the spiral moving inside the flushed oil pipeline along its internal surface.

EFFECT: invention allows removing from oil pipelines not only sludge consisting of oil ageing products, but also heavy solid fouling particles.

2 cl, 3 dwg

Description

The invention relates to energy and can be used in thermal power plants with steam turbines of large unit power, having branched oil pipelines of control systems, lubrication of bearings of the turbine unit and generator shaft seals.

The method can also be used to clean pipelines used to transport various liquids: irrigation water (from sludge), network hot water (from corrosion products) or oil pipelines (from the so-called "heavy oil" deposited in a dense layer).

During operation of the turbomachine, clogging of oil systems occurs due to the precipitation of sludge, corrosion products of the internal surfaces of pipelines and parts of assemblies, particles of rubbing elements, as well as housing corrosion-resistant coatings.

A known method of cleaning the oil system of a turbomachine (Recommended Practices the cleanning of Steam turbin Generator Oil Systems, ASME Standard No. 117, New York, 1968) is carried out by periodically supplying the system with standard pumps pre-heated to the maximum permissible oil temperature.

The disadvantage of this method is its long time, because A large number of cycles are required to cool and heat the oil.

A known method of cleaning the oil system (SU 300639, class F01D 25/18, 12/15/1974), which has become widespread in the USSR under the name of hydrodynamic. The essence of this method is to pump oil through specially organized (allocated) circuits with an increased speed sufficient for the development of developed turbulence necessary for high-quality cleaning of the oil system.

The disadvantage of this method is that only short pressure oil pipes of small diameter from the pressure manifold to the bearings were well cleaned. It was not possible to ensure high-quality cleaning of the entire pressure head manifold, and especially the drain, non-fill collector.

A known method of cleaning the oil system of a turbomachine (SU 1010302, class F01D 25/18, 04/07/1983) is carried out by supplying oil preheated to the maximum permissible temperature in which, in order to intensify the cleaning process and improve its quality when the temperature of the pipelines reaches the oil temperature remove the oil from the oil lines and feed into the drain manifold a cooler chemically inert with respect to the metal and oil (for example, liquefied nitrogen), and after cooling the oil system pipelines to a temperature According to operating conditions, heated oil is fed again, and these operations are alternated until the oil system is completely cleaned.

This method allows you to accelerate the separation of contaminants from the inner surface of the drain manifold, without ensuring their effective removal into the oil tank. The disadvantage of this method is also the long cleaning time.

A known method of cleaning the oil system of a turbomachine (SU 1656180, F01D 25/08, 06/15/1991), in which the oil system is carefully sealed, all connectors are sealed, the oil in the oil tank is deoxygenated, for example, by purging the oil with an inert gas (nitrogen) through a bubbler, after which the oil heated to a temperature of 120-130 ° C and pumped through the oil system, and after pumping it with a maximum flow rate, the entire volume of oil is cooled and again pumped through the oil system.

The disadvantages of the method are the presence of technological operations unusual for the operating personnel, the complexity of the work of sealing the system and cooling the entire volume of oil directly in the oil tank, the absence of combinations of thermal shock and hydro-pulse exposure, which reduces the cleaning efficiency.

Closest to this technical solution is a method of cleaning the oil system of a turbomachine (SU 1652629, F01D 25/18, 05/30/1991) by alternately pulsing pumping oil preheated to the maximum permissible temperature and injecting finely dispersed gas (air) into it. The method of cleaning the oil system of a turbomachine is carried out by a device containing an oil tank, a starting pump, a pressure and drain piping, a flushing injector connected to a pressure nozzle by a discharge nozzle, and also a source of compressed air from which air is supplied to the injector through a spool. The spool is made rotating and rigidly bonded to a pressure pulsator. The latter is installed in the suction pipe of the injector and is made in the form of a rotary damper.

An air-oil mixture is formed in the injector mixing chamber, which in the pulsating flow mode impacts particles of contaminants and detaches them from the inner surfaces of the oil pipelines.

The disadvantage of this method is that the air pressure from a standard compressor installation, which is supplied to the injector neck in the form of an active medium, is clearly not enough to create an air-oil flow with increased pressure and speed necessary to excite the developed turbulence regime.

In addition, when air is supplied to the neck (low pressure zone) in portions that take the form of plugs or stuck “shells” in a narrow place (neck), a general decrease in the flow rate occurs. Effective cleaning of the walls of the pipelines does not occur. This flow stream leads to water hammer and is accompanied by mechanical shaking of pipelines, which contributes to cleaning. However, this can lead to both softening at the places of welding and flange connections, and damage to places of case connections. Moreover, drain oil pipelines are still not washed (as in the hydrodynamic method of washing), while the contaminants in the drain manifold can be “stored”, which is extremely dangerous. In the event of vibration on the turbine unit, oil piping vibrates automatically, accumulated contamination can be carried to the bearings and cause an accident. The latter is confirmed by the incidents.

The technical result to which the invention is directed is to increase the efficiency of thermohydroimpulse effects on contaminants and their removal from pipelines, provided that costs are minimized without any adverse side effects, such as decompression of the hydraulic system due to water hammer and mechanical vibration of the pipelines.

The specified technical result is achieved by the fact that in the method of cleaning the oil system of the turbomachine by alternately pulsing pumping the oil preheated to the maximum allowable temperature and blowing finely dispersed gas (air) into it, pipelines having a temperature not higher than the ambient temperature are drained into the oil before it is drained a stream of hot oil, and this stream to increase the thermoshock effect in the wall zone through a flat tapering nozzle is directed along the tangent the inner forming surface of the cylindrical body of the flushing injector-snail, which coincides with the inner surface of the flushing pipeline, due to which they form a torn-like oil-air vortex, which additionally acts by centrifugal force on the layer of deposits adhering to the surface, and the axial vector of compressed air supply through the annular confuser provides the resulting (total) vector the direction of motion of a rotating vortex with increased kinetic energy in a spiral moving inside the wash oil pipeline along its inner surface.

The indicated technical result is also achieved by the fact that compressed air is blown from the storage tank through an annular divider-confuser, which provides direction to the wall zone along the ring with increased kinetic energy, and the pressure is changed pulse by a damper valve, which ensures air cavitation in the oil-air rotating stream.

Figure 1 presents the structural diagram of the oil system for implementing the cleaning method.

Figure 2 shows a General view of the design of the injector-snail.

Figure 3 shows sections aa and bb of the injector-cochlea.

A method for cleaning the oil system of a turbine unit comprises an oil tank 1 to which a pump 2 is connected, which supplies oil to the heat exchangers 3 in separate lines. On one of these lines, after the heat exchanger, a flushing injector 4 of a conventional design in the form of a jet pump can be installed. An emulsifier 5 is installed in the common pressure line, which saturates the oil with air and creates a gas-liquid stream of a finely dispersed structure. The pressure manifold of oil 6 is located along the bearings 7 of the turbine unit. From the pressure manifold, oil is supplied by pressure sections 8 through jumpers 9 to the oil drain pipes 10 in addition to the bearings, and from them to the drain manifold 11. High-speed shutters (BDZ) are installed on the jumpers 12. During operation of the turbine unit, the used oil is drained into bearings in the bearings and then of them into the drain manifold.

Injectors-snails 13 are installed at the end of the drain manifold 11 and on large oil drain pipes of large diameter 10. The oil inlet pipe 14 to the injector-snail is connected tangentially and is made in the form of a narrowing flat nozzle, air injection nozzles 15 are introduced into its side parts.

An annular dissector-confuser 16 is installed in the end part of the injector-snail, which accelerates the longitudinal air impulse of the oil-air vortex with the aim of pushing and imparting to the latter a spiral-like movement inside the flushed pipeline, and a pressure pulsator 17 is installed between the compressed air tank 18 and the inlet divider-confuser the latter and is made in the form of a high-speed damper valve.

Compressed air is also supplied through additional emulsifiers 19 to the jumpers 9 installed in the immediate vicinity of the BDZ or immediately after it, to the horizontal section of the water trap loop 20 (emulsifier-barbater) and to the vertical section of the water trap 21 (emulsifier-airlift). An oil drain valve 22 is installed on the oil recirculation line by draining it into the oil tank 22. In the oil tank 1 there are standard frame filters 23, in the lower part of which additional dirt collecting pockets 24 are installed (fixed).

Compressed air is supplied to the battery 18 either directly from the standard compressor, or, if necessary, more cooling, through an air conditioner or steam ejector unit (PES) 25, designed to cool the atmospheric air supplied to the production premises of the station.

The method of cleaning the oil system is as follows.

Mechanical particles that have been motionless for a long time can be so adhered to the metal that considerable efforts will be required to detach (shear) them.

Therefore, to increase the cleaning efficiency, the “heat stroke” effect is used, which is realized due to the temperature difference between the oil (heated to the maximum permissible temperature) and the metal of the pipes, which, when emptied, are cooled, if necessary, with cold air supplied through a standard air conditioner or steam ejection unit (PES) 25. The temperature difference should be at least 50 ° C. The essence of the effect is to use the difference in the coefficients of thermal expansion of mud deposits, concentrated on the inner surface mainly in the lower part of the pipeline, and the metal of the pipeline along the entire inner perimeter. Due to the ring supply of heat to the entire surface of the pipeline and the greater thermal conductivity of its metal, it expands faster than contaminants, as a result of which the latter exfoliate from the metal, and then are carried away by the general flow of oil.

To implement the cleaning method, the oil is preliminarily pumped along the contour of the oil tank 1, pump 2, one of the heat exchangers when the oil supply valve to the pressure manifold is closed, then along the oil discharge line through the oil drain valve 23 when the spring is completely weakened (removed) or the valve is removed from the housing. At the same time, heat carrier 3 is supplied to the heat exchangers (hot network water or water from the peak boiler house). As a result of pumping the oil along the specified circuit, the oil is heated to the maximum permissible temperature. Then the recirculation line is closed by fixing the oil drain valve 23 in the closed position, and the heated oil is pumped 2 to the pressure manifold 6 either using the injector 4 or directly through the emulsifier 5. Further along the pressure sections 8, through jumpers 9 with high-speed shutters (BDZ) 12 the oil enters the drain oil lines 10, and of them into the drain manifold 11.

Emulsifier 5 is used to create a gas-liquid stream of finely dispersed structure. It is a bundle of tubes of small diameter inserted into the main oil pipe, each of which is connected to a compressed air collector at the inlet, and ends on the opposite side with a Laval nozzle. The nozzles are evenly spaced across the pipeline and their direction coincides with the direction of the oil flow. In addition to the emulsifier 5, additional emulsifiers 19 can be used in the washing circuit, made in the form of nozzles for introducing compressed air into the oil pumped through the jumpers, an emulsifier of the same design 20, installed in the lower horizontal part of the hydraulic lock (emulsifier-barbater), and 21 on vertical section of the hydraulic lock (emulsifier-airlift).

The snail injectors 13 are installed on the oil drain lines 10 and at the end of the drain manifold 11. Hot oil enters the snail injector body by means of a nozzle 14, which is a flat narrowing nozzle, with nozzles 15 for injecting compressed air mounted on its sides. This makes it possible to form a rotating oil-air vortex stream of a finely dispersed structure with the provision of large-scale vortex turbulence in the oil drain pipes and in the drain manifold and to use the kinetic energy of the gas-liquid stream to excite air-cavitation processes that contribute to the separation of heavy and adherent pollution fractions from the pipeline walls. "Snails" create a circular rotation of the gas-liquid flow, directing the bulk of its energy into the wall layer of the pipeline. Due to the increased velocity gradient in the boundary layer of pollution, they experience significantly greater dynamic loads (and, consequently, the effects of separation forces).

The effective pushing of such rotating tornado-like vortices is carried out by an annular dissector-confuser 16, which provides amplification of the longitudinal air impulse, and a fast-acting shutter 17 installed between the compressed air tank 18 and the dissector-confuser, which operates in the high-speed valve mode, with the interval of operation determined by the pressure drop in the vessel compressed air 18.

Compressed air supplied through additional emulsifiers 19 to the jumpers, and then to the oil drain lines, and 20 to the horizontal section of the hydraulic lock loop, and also to the vertical section of the hydraulic lock loop through airlift 21, allows creating air cavitation in the local parts of the system, thereby contributing to the removal of contaminants of them.

The washing time is determined by the clogging of the frame filters 23, supplemented with a mesh with a smaller cell, and the amount of dirt in the pockets 24. The frame filters are supplemented with grids, for example, of polyamide fabric with a smaller cell, as the intervals between cleaning (purging) increase. During technological interruptions in the supply of oil to the oil system, the oil lines are ventilated by blowing air, if necessary, cold.

Thus, the flushing of oil systems with a complex branched piping system of various diameters, including drain pipes and collectors of large length and large diameter, is provided by a new efficient turbothermopneumohydropulse method.

The method of cleaning the oil system of a turbomachine has been successfully used to flush the oil systems of T-250 / 300-240 TMZ turbines and PT-80 / 100-130 / 13 LMZ turbines at Mosenergo TPP-26, which made it possible to almost completely remove from all oil pipelines, including drain pipes only sludge, consisting of oil aging products, but also solid heavy particles, which are especially dangerous for bearings and the entire water supply if they are removed, for example, when vibration occurs during operation of the turbine unit, as well as during controlled operation after major maintenance installation if the drain manifold has not been cleaned properly.

Claims (2)

1. A method of cleaning the oil system of a turbomachine by alternately pulsing pumping oil preheated to the maximum permissible temperature and blowing finely dispersed gas (air) into it, characterized in that pipelines having a temperature not exceeding ambient temperature sharply supply a stream of hot oil, and this stream to increase the thermoshock effect in the wall zone, through a flat tapering nozzle is directed tangentially to the inner generatrix of the surface the cylindrical body of the flushing injector-snail, which coincides with the inner surface of the flushed pipeline, thereby forming a torn-like oil-air vortex, which additionally acts by centrifugal force on the layer of deposits adhering to the surface, and the axial vector of compressed air supply through the annular divider-confuser provides the resultant (total) vector the direction of motion of a rotating vortex with increased kinetic energy in a spiral moving inside the washed oil line the inner surface thereof. 2. The method according to claim 1, characterized in that the compressed air is blown from the storage tank through an annular divider-confuser, providing direction to the wall zone along the ring with increased kinetic energy, and the pressure is changed pulse by a damper valve, providing in an air-air rotary flow process of air cavitation.

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