RU2325606C2 - Method of gas turbine engine fuel header cleaning from coke deposits and scale - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to items cleaning from coke deposits and scale, in particular, to cleaning of fuel header of combustion chamber and afterburner of gas turbine engine by physical-chemical method, and may be applied in aircraft engines engineering, shipbuilding, power machine-building and other industries. Method of gas turbine engine fuel header from coke deposits and scale includes header soaking in water alkaline solution, rinsing in water and blowing with compressed air, at that soaking is done in boiling solution at temperature from 120°C to 165°C, solution is made of alkalis KOH or NaOH, or their mixture with alkali concentration in solution or total concentration of their mixture in solution from 600 to 800 g/l.

EFFECT: invention allows increasing of cleaning efficiency of fuel header internal surfaces with preservation of leak-tightness and soldered joints strength, and reduces labor expenditures.

4 cl, 3 dwg

Description

The invention relates to the cleaning of products from coke deposits and carbon deposits, in particular to the cleaning of the fuel manifold of the combustion chamber and afterburner of a gas turbine engine by the physicochemical method, and can find application in aircraft engine building, shipbuilding, power engineering and other industries.

A known method of cleaning the fuel manifold of a gas turbine engine from coke deposits and soot, including installing the fuel collector in a furnace heated to a temperature of 600-800 ° C, feeding after heating the furnace to a specified temperature of compressed air in the internal cavity of the fuel collector and holding the collector in the furnace after termination compressed air supply (see patent RU No. 2225285, CL. F28G 11/00, publ. June 27, 2005).

Despite the satisfactory quality of cleaning, the disadvantage of this method is the destruction of the soldered joints of the fuel collector due to the oxidation of solder that occurs at a high temperature of the cleaning process.

Closest to the proposed one is a method of cleaning the fuel manifold of a gas turbine engine from coke deposits and soot, including loosening the combustion products with a composition containing stearic or oleic acid, triethanolamine and mineral oil, removing the combustion products with ultrasound in baths with an aqueous alkaline solution at a temperature of 55-60 ° C for 8-10 minutes, washing and drying the collector (see USSR author's certificate No. 214000, publ. 03.20.1968).

However, this method is not effective enough due to the inability to completely remove combustion products from hard-to-reach spots of the fuel collector; In addition, fatigue failure of the soldered joints of the collector along the eutectic interphase surfaces of the solder as a result of vibrations of the collector under the influence of ultrasound takes place.

The technical result of the claimed method is to increase the cleaning efficiency of the internal cavities of the fuel collector while maintaining the tightness and strength of the soldered joints and reducing the complexity.

The specified technical result is achieved by the fact that in the method of cleaning the fuel manifold of a gas turbine engine from coke deposits and soot, including holding the collector in an aqueous alkaline solution, washing in water and blowing with compressed air, according to the invention, the exposure is carried out in a boiling solution at a temperature of from 120 ° C to 165 ° C. In this case, KOH or NaOH alkalis are used in the solution, or their mixture with an alkali concentration in the solution or with a total concentration of their mixture in the solution from 600 to 800 g / l.

KOH and NaOH present in the alkali solution or their mixture (KOH + NaOH) saponifies impurities and emulsifies deposits; in addition, these alkalis have the most effective cleaning properties with respect to resinous substances, as well as asphaltene-resinous and coke-like substances that are products of coke deposits.

The specified range of alkali concentration or the total concentration of the mixture of alkalis allows you to completely remove coke deposits and carbon deposits, as well as maintain a predetermined, within the specified range, boiling point of an aqueous alkaline solution during the aging operation.

At temperatures below 120 ° C and a solution concentration of less than 600 g / l, it is impossible to completely clean the collector cavities, in particular in places with maximum coke deposits and in inaccessible places (bending areas), due to the low rate of coke deposits and carbon deposits reacting with alkali. At a temperature of more than 165 ° C and a concentration of more than 800 g / l, the degree of purification does not increase, and at the same time there are certain technological difficulties in bringing the tank (bath) with the solution to the technological mode of purification due to the correspondence of such concentration of the solution to the solid state of aggregation at room temperature .

Oxidizing agents can be added to the aqueous alkaline solution, which makes it possible to intensify the cleaning process.

Washing can be carried out at a water temperature of 50-100 ° C, i.e. hot water, which leads to faster and more efficient cleaning of residual alkaline solution of the internal cavities of the collector.

Rinsing in water and purging can be done periodically, which allows more efficient cleaning of the collector.

Figure 1 schematically shows a fuel manifold located in a bath with an aqueous alkaline solution, the operation of exposure;

figure 2 - fuel manifold located in the bath with water, the washing operation;

figure 3 - fuel manifold - the operation of the purge air.

A device for implementing the method comprises a container 1 filled with an aqueous alkaline solution, in which the fuel manifold is held, consisting of two tubes 2 (I and II cascades), one of which is the cascade I pipe, is shown in the drawing, and nozzles 3. Capacity 1 contains a pallet 4 and heating elements 5 (tena). The tray 4 is made in the form of a metal grill separating the fuel manifold 2 with nozzles 3 from the heating elements 5. The device also contains a tank 6 filled with hot water with a pipeline 7 for supplying water. The supply of compressed air to purge the channels of the nozzles 3 is carried out using a flexible reinforced hose 8 connected to a source of compressed air (not shown).

The method is implemented as follows.

The fuel collector is installed in a container 1, pre-filled to a level that completely covers the collector, with an aqueous alkali solution, for example, with KOH alkali with an alkali concentration of 700 g / l. The container 1 is covered with a lid and the aqueous alkaline solution is heated using heating elements 5 to a temperature of, for example, 145 ° C, at which the solution boils. The collector is kept in a boiling solution, for example, for 8 hours, while at least every 2 hours, the collector is washed with hot water at a temperature of 70 ° C and purged with compressed air at a pressure of 2-4 kg / cm ² . To do this, using a hoist, remove the collector 2 with nozzles 3 from the tank 1 and install in the tank 6, after washing, the collector 2 with the nozzles 3 is removed with the hoist from the tank 6 and install on the supporting surface for the purge operation. After purging, the collector is again installed in tank 1 and the soaking operation is carried out, after 2 hours of soaking, the washing and purging operations are repeated again, and so on, until the set soaking time has elapsed, during which the fuel collector is completely clean of coke deposits and carbon deposits. The alkali concentration in the solution and the temperature of the aqueous alkaline solution are monitored using sensors (not shown). In the case of reducing the set boiling point, the necessary amount of alkali is added to the tank 1 to increase the temperature of the solution. If the specified alkali concentration in the solution is exceeded, the required amount of water is added to the solution.

During the soaking of the collector in a boiling alkaline solution, the saponification of contaminants (coconut deposits and soot) occurs, during the washing process, the residues of the alkaline solution are boiled up intensively and additional pollution is peeled off, and when the collector is purged with compressed air, the residues of coke deposits and soot are removed from the inner cavity of the tubes 2 and from nozzle channels 3.

After cleaning the fuel manifold, nozzles are monitored using known technical means, such as endoscopes. Also, quality control is carried out to remove residual alkaline solution from the internal channels and cavities by spilling the collector and nozzles with distilled water and determining alkali metal ions and pH in it by a known method.

The implementation of the method is considered using KOH alkali as an example. When using alkali NaOH or a mixture of alkalis NaOH + KOH with different or the same concentrations of alkalis, the quality of purification and the implementation of the method do not change. The alkali concentration in the solution or the total concentration of their mixture in the solution can vary from 600 to 800 g / l. The exposure time of the fuel collector in an aqueous alkaline solution can be from 2 to 10 hours. The alkali concentration in the solution and the exposure time are selected depending on the thickness of the coke deposits and carbon deposits. To intensify the cleaning process, oxidizing agents, for example nitric acid salts of alkali metals, are added to the solution.

Claims (4)

1. The method of cleaning the fuel manifold of a gas turbine engine from coke deposits and soot, including exposure of the collector in an aqueous alkaline solution, washing in water and blowing with compressed air, characterized in that the exposure is carried out in a boiling solution at a temperature of from 120 to 165 ° C, while alkali KOH or NaOH or their mixture with an alkali concentration in solution or with a total concentration of their mixture in solution from 600 to 800 g / l is used in the solution. 2. The cleaning method according to claim 1, characterized in that oxidizing agents are added to the aqueous alkaline solution. 3. The cleaning method according to claim 1, characterized in that the washing is carried out at a water temperature of 50-100 ° C. 4. The cleaning method according to any one of claims 1 to 3, characterized in that the washing in water and purging is carried out periodically.

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