Method for collecting and treating waste water from engine washing

ES 2 343 409 T3

DESCRIPTION

System and devices to collect and treat wastewater from engine washes.

Technical field

The present invention relates generally to the field of jet engine washing, using especially washing liquids such as water and detergent or only water, and more specifically to a system, and devices for collecting and treating wastewater from engine washing. motor and a mobile car comprising this type of system.

Background of the invention

A gas turbine engine installed as an aircraft engine comprises a compressor that compresses ambient air, a burner that burns fuel together with the compressed air, and a turbine to drive the compressor. The expanding combustion gases power the turbine and also create the thrust used to propel the aircraft.

Air-breathing machines like jet engines consume large amounts of air. The air contains foreign particles in the form of aerosols or larger particles that then enter the engine with the air stream. Most of the particles will follow the path of the gas through the engine and will be expelled with the exhaust gases. However, there are particles with adherent properties on the components in the gas path of the engine that change the aerodynamic properties of the engine and more particularly that reduce the performance of the engine. Typical pollutants found in the aeronautical environment are pollen, insects, engine exhaust, leaking engine oil, hydrocarbons from industrial activities, salt from the nearby sea, chemicals from thawing of the aircraft and airport ground materials such as dust.

Contaminants adhere to components in the engine gas path causing fouling in the engine. The consequence of fouling in the gas path is a slower running engine. With the reduction in performance, the engine is less economical to operate and has higher emissions. Scale will cause more fuel to be burned to achieve the same thrust as with a clean engine. In addition, an environmental drawback will appear with the increased fuel consumption in the form of carbon dioxide emissions. In addition, burning more fuel will result in higher engine burner temperatures. This will be followed by exposure to high temperature of components in the hot section of the engine. Exposures to a higher temperature will shorten the life of the engine. Higher combustion temperatures will cause increased NOx formation which is yet another environmental drawback. In summary, the operator of a fouled engine will experience reduced engine life, unfavorable economic operating conditions, and higher emissions. Airline operators will therefore have a great interest in keeping the engine clean.

It has been found that the only reasonable way to combat fouling is to wash the engine. Washing can be done by directing a jet of water with a garden hose towards the inlet of the motor. However, this method has limited success due to the simple nature of the procedure. An alternative method is the pumping of the washing liquid through a manifold with special nozzles directed towards the inlet face of the engine. The manifold would be temporarily installed on the engine cover or fairing during the wash operation. Simultaneously with the spray of washing liquid towards the engine inlet, the engine crankshaft will be rotated using its starter motor. The rotation of the crankshaft improves the washing result through mechanical movements. The rotation of the shaft allows the wash liquid to move over a greater surface area in addition to improving the penetration of the liquid into the interior of the motor. The method works successfully on most types of gas turbine jet engines such as turbojets, turboprops, turboprops, and prior mixed or mixed turbofan engines.

A correct flushing operation of a gas turbine engine can be confirmed by observing the flushing liquid exiting the engine through the engine exhaust. In the engine exhaust, the washer fluid has become a residual fluid. Residual fluid can leave the engine exhaust as a stream of fluid that spills onto the ground. Alternatively the residual liquid can be transported with the air stream in the form of fine droplets where the air stream is the result of the rotation of the motor shaft. This airborne liquid can be carried a significant distance before falling to the ground. It is shown in actual wash operations that the residual liquid spreads over a large surface area, typically more than 20 meters downstream of the engine outlet. It is not desired to spread the residual liquid on the ground. The purpose of this invention is to provide a method and apparatus for collecting residual liquid exiting the engine.

The waste liquid leaving the engine in the wash is composed of the wash liquid entering the engine together with the released scale material, combustion solids, turbine and compressor lining material, and fatty products and oil. This residual liquid can be dangerous. As an example, analysis of the water collected from the actual turbine engine wash operations showed a cadmium content. Cadmium comes from the coating material on the compressor blades released during washing operations. The

ES 2 343 409 T3 Cadmium is very environmentally sensitive and may not be disposed of on site. This residual liquid must be treated to separate the hazardous components before being disposed of in a landfill.

Gas turbine aviation engines can be of different types such as turbojets, turboprops, turboprops, or unmixed turbofan engines. These engines cover a wide range of performance and may include different design details due to different manufactures. The types of aircraft for a defined service can be offered by different aircraft manufacturers and therefore the design of the aircraft and its engines can vary. Also, the aircraft manufacturer may offer different engine options for the same type of aircraft. The many combined possibilities of engines on aircraft types and from different aircraft manufacturers create a practical problem in the design of a system for the collection and treatment of residual wash liquid that is generally applicable to most aircraft fitted with wings. US 5,899,217, Testman, Jr. It describes an engine wash recovery system that is limited to small engines and particularly turboprop engines since the container used in the invention is not applicable to the air stream emanating, for example, from large turbofan engines.

The collection of residual water from the engine wash can be carried out by hanging canvas collectors under the engine nacelle. However, any resulting operation on anything that is hooked onto a motor has the disadvantage that it can damage the motor.

DE-U-94 20 362 describes a "Cleaning Substance Attachment Device for Cleaning Aircraft Engine Compressors". This comprises a diverter tube intended to be placed on the exhaust cone of an aircraft engine. The diverter tube is connected to a collection device, but separation of liquid from the air and vapor stream is not provided.

Summary of the invention

Therefore, an object of this invention is to provide an apparatus that allows the collection and treatment of residual water from the engine wash for a wide range of aircraft types including the major aircraft types.

A further object of the present invention is to provide an apparatus for removing hazardous components from wastewater before it is disposed of.

A further object of the present invention is to provide an apparatus for collecting and treating engine wash wastewater that does not require physical contact between the collecting device and the engine.

Another object of the present invention is to provide an apparatus that enables engine cleaning operations.

These and other objects are achieved in accordance with the present invention by providing a device having the characteristics defined in claim 1. Preferred embodiments are defined in the dependent claims.

The solution according to the present invention provides several advantages over existing solutions. An advantage is that hazardous particles, substances, or other types of content, such as released scale material, combustion solids, compressor and turbine lining material, heavy metals, and grease and oil products, can be removed or separated from the residual liquid resulting from a washing operation in an efficient and environmentally friendly way.

Another advantage is that the invented device can be used with different types and designs of gas turbine aircraft engines, such as turbojets, turboprops, turboshafts and mixed or unmixed turbofan engines, and also with different types and designs of aircraft. from different manufacturers because the devices and systems can be matched exactly to a specific engine or aircraft. Consequently, the present invention provides a very high degree of flexibility since one system can be used for all types of engines and aircraft, that is, the present invention is provided for a waste treatment and collection wash liquid generally applicable to the most aircraft with wings. This causes cost savings because one and the same mobile system or trolley included in the system can be used for all types of engines and aircraft.

A further advantage is that there is no physical contact between the collector device and the motor, which avoids the possibility of damaging the motor.

Further objects and advantages of the present invention will be discussed below by way of example embodiments.

Brief description of the figures

Preferred embodiments of the invention will now be described in greater detail with reference to the accompanying drawings, in which:

Figure 1 shows a cross section of an unmixed turbo fan gas turbine engine.

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Figure 2 shows how residual liquid can escape from an unmixed turbofan motor during flushing.

Figure 3 shows the device for collecting residual liquid according to the invention.

Figure 4a shows a procedure for treating residual liquid before it is disposed of in a landfill.

Figure 4b shows an alternative waste liquid treatment procedure before it is disposed of in a landfill.

Figure 5 shows the residual liquid collection device and the treatment device installed on a mobile cart for practical use in aircraft service at airports.

Figure 6 shows the mobile cart with the waste water collection device and the treatment device positioned for servicing an engine mounted under a wing.

Figure 7 shows the mobile trolley with the wastewater collection device and the treatment device positioned for the service of a tail-mounted engine.

Figure 8 shows one embodiment of the separator profiles of the droplet separator shown in Figure 3.

Description of preferred embodiments

The invention can be practiced on various types of engine such as turboshaft, turboprop, turbojet and mixed / unmixed multi-axis turbofan engines. The invention can be practiced on under-wing mounted engines as well as on tail mounted engines as further shown in Figures 6 and Figure 7.

Figure 1 shows a cross section of an unmixed turbofan engine. This engine is of a common type found for example in large passenger service aircraft 11. The motor 1 is composed of a vent section 102 and a core motor section 103. Airflow is indicated by arrows. The motor 1 has an inlet 10 through which air enters the motor. Air circulation is activated by fan 15. A portion of the inlet air exits through the outlet 11. The remaining portion of the inlet air enters into the core motor through the inlet 13. The air in the core motor is compressed by the compressor 17. The compressed air together with the Fuel (not shown) burns in burner 101 causing hot pressurized combustion gases. The hot pressurized combustion gases expand toward the core engine outlet 12. The expansion takes place in two stages. In a first stage the combustion gases expand within an intermediate pressure while driving the turbine 18. In a second stage the combustion gases expand towards the ambient pressure while driving the turbine 16. The turbine 16 drives the fan 15 by means of of the shaft 14. The turbine 18 is driving the compressor 17 by means of a second shaft 19 where the second shaft 19 is in the form of a shaft coaxial with the first shaft 14.

In Figure 2 the motor described in Figure 1 is subjected to a motor wash. Similar parts are shown with the same reference numbers as in Figure 1. Figure 2 shows a side view of engine 1. Engine 1 is an "under-wing engine" installed under wing 21 with the support 22 where wing 21 is part of aircraft 2. A manifold (not shown) for injecting washing liquid is installed at the engine inlet 10 of engine 1. The manifold maintains a plurality of nozzles 24 in the upstream position of the fan. A washing pump unit (not shown) pumps a washing liquid through nozzles 24 in the form of sprays 25 directed towards the fan and the air inlets of the core motor. The liquid cleans the gas paths of the fan and core motor. To improve the cleaning effect, the motor shafts are bent and rotated by the starter motor. The bending of the shafts allows the liquid to move around the interior of the motor for an improved cleaning effect. The rotation of the shafts causes an air circulation that draws the liquid towards the motor outlet, consequently the liquid will exit the motor from the rear. The liquid coming out of the motor is residual liquid.

The liquid will exit the motor in at least five different ways as described in Figure 2. The first category of liquid, stream 201, will exit the core motor outlet 12 in the form of airborne droplets. The droplets constituting stream 201 are generated within the engine by the movement of the compressor and the turbine blades. Stream 201 is composed of droplets with a great diversity of sizes where the different sizes of the droplets have different characteristics. Smaller droplets, that is, droplets measuring less than 30 microns will typically evaporate rapidly in ambient air due to their small size. The droplets of less than 30 microns therefore do not worry much in the process of collecting the consumed water for the reason of evaporation and that these represent only a small volume of the consumed liquid. The largest droplets in stream 201 are droplets the size of rain droplets, for example 2,000 microns. These droplets are heavy and will not evaporate but will fall to the ground by gravity. Droplets greater than 30 microns but less than 2,000 microns will be carried with the air stream and will fall by gravity on the ground 23 typically about 20 meters behind the engine outlet. The second category of liquid, the current

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202, is composed of chains of liquid and other large volumes of liquid. Stream 202 falls rapidly to the ground by gravity. The third category of liquid, stream 203, is liquid poured as a solid stream out of the core motor outlet 12. This liquid is typically poured vertically into the ground 23. The fourth category of liquid, stream 204, is liquid that is poured out of the outlet 11 of the vent. This liquid falls basically vertically on the ground 23. The fifth category of liquid, stream 205, is liquid that falls or is poured from the bottom of the engine nacelle. The source for this liquid is for example the combustion chamber drain valves that open. According to the invention, a method and an apparatus for collecting the residual liquid exiting the engine is described as described in Figure 2.

Figure 3 shows a side view of the motor 1, and how the residual liquid is collected during washing according to the invention. Similar parts are shown with the same reference numbers as in Figure 2. The manifold 3 is composed of a droplet separator 31, a bucket 36 and a drop 302. The liquid exiting the motor as stream 201 is separated from the carrier air in droplet separator 31. Liquid exiting the motor such as stream 202, stream 203, stream 204, and stream 205 is collected by drop 302. Liquid emanating from droplet separator 31 and drop 302 is collected in bucket 36.

The falling droplet separator 31 is comprised of a frame enclosing droplet separator profiles. The droplet separator 31 has an inlet face 32 directed toward the air stream 201 and an outlet face 33 opposite the inlet face 32. Stream 201 enters the droplet separator through the inlet face 32 and exits the droplet separator through the outlet face 33. Liquid is trapped in separator 31 so that stream 301 is essentially free of liquid after passing through droplet separator 31. The droplet separator 31 is composed of separator profiles arranged vertically (see Figure 8) in a frame. The separator profiles deflect the air stream. As a result, the moment of the falling droplets makes them impinge on the surface of the profile. The falling droplets stick together and form a liquid film. The influence of gravity on the film causes the liquid to drain towards the bottom of the profile and exit the droplet separator through face 34 as stream 35. Stream 35 of discarded liquid falls by gravity into bowl 36.

The droplet separator 31 is composed of a frame enclosing droplet separator profiles. Figure 8 shows the technique for separating airborne droplets with the use of spacer profiles. The direction of the air stream is shown by arrows. The droplet separator profiles are arranged parallel to allow air circulation through the separator. The profiles of the droplet separator are arranged vertically allowing the liquid to find its way downwards by gravity on the surface of the profile. Figure 8 shows a cross section of three droplet separator profiles looking from above and below. The droplet separator profile 81 is configured as shown in Figure 8. At about the middle distance from the leading edge to the trailing edge of the profile, a liquid trap 82 is formed as a gap for collecting liquid on the surface of the profile 81. The droplets 84 are carried with the air stream between the droplet separator profiles. Inside the separator the air is deflected as a result of the geometry of the profile 81. The deviation of the airflow is sufficiently fast not to allow the droplets to stay with the air. The inertia of the droplets 84 allows the droplets to move without deviating and impinge on the profile 81 at point 83. As the liquid continues to accumulate on the surface of the profile a liquid film 85 forms where the tangential forces of the current of air will transport liquid 85 into liquid trap 82. In the liquid trap 82 the liquid will develop and pour downwards by gravity.

Figure 3 shows drop 302 installed under engine 1. Drop 302 will collect liquid 202, 203, 204 and 205 as shown in Figure 3. Drop 302 has a front end 39 and a rear end 38, where the end Front 39 is positioned vertically higher than rear end 38. Since front end 39 is higher than rear end, the drop is inclined. The inclination of the drop 302 will allow the liquid in the drop to flow from the left to the right in Figure 3. The rear end 38 is positioned above the bowl 36 so that the liquid will be poured out of the drop 302 into of bucket 36 as stream 37. According to an alternative embodiment, drop 302 is incorporated into bucket 36 and tank 302, forming a single unit.

The liquid that comes out of the motor during washing contains water, detergent and foreign matter. Foreign matter is in the form of solids and ions dissolved in water. What comes out of the engine during a specific wash depends on a number of issues such as when the last wash was performed, the environment in which the engines run, etc. Furthermore, the residual liquid may on one wash occasion contain a high amount of solids while on another wash occasion it may be low in solids. Similarly the residual liquid may on one wash occasion contain a high amount of ions while on another wash occasion it may be low in ions. This results because the wastewater treatment system must be flexible in its design so that the most appropriate treatment can be carried out on each occasion. The wastewater treatment system described in Figure 4a shows the components and process according to a treatment scheme. Figure 4b shows the same components still in a different treatment scheme. The schemes in Figure 4a and Figure 4b are examples of two possible schemes where any person skilled in the art can design additional schemes and still remain within the scope of the invention.

There may be times for washing when residual water is not dangerous. In that case the procedure for removing the hazardous components would be unnecessary. The non-hazardous waste liquid can then be disposed of directly into a landfill. In order for the unit operator to decide whether the wastewater should be further treated before being discharged or simply discharged into a landfill, the operator can perform an en5

ES 2 343 409 T3 sayo. One possible test for this purpose is to measure the electrical conductivity of the wastewater. This test makes it possible to decide on direct disposal to a landfill or allows further processing of wastewater. This can be done using a small, portable, battery-powered conductivity meter. According to this embodiment, the test procedure would then be to stick the measurement probe into the discarded water and record the conductivity reading. The recorded values ​​would then be compared to a table of acceptable and unacceptable values ​​representing the experience gained from laboratory analysis of wastewater from engine washes. The use of a conductivity meter to measure electrical conductivity is just one example. Depending on the type of engine and the environment in which the engine operates, the operator may find alternative test methods that are more appropriate.

In Figure 4a, a bucket 36 collects the waste liquid streams as stream 401. From an opening in the bottom of the bucket 36 the waste liquid enters the tank 303. The waste liquid in the tank 303 can settle for some time , typically less than 30 minutes. Particles that have a density greater than that of water will settle to the bottom 406 of tank 303. The particles that will typically settle to the bottom are solid fuel residues, coked hydrocarbons, compressor scale material, and the like. Particles with less density than water will float on the surface 407 of the discarded liquid. The particles that will typically float to the surface are oils, fats, pollen, insect debris, bird strike debris, and the like. Between bottom sediment and surface materials the discarded liquid may contain metal ions and very small particles that do not settle to the bottom or float to the surface.

Figure 4a shows the processing of residual liquid without sediment into a non-hazardous liquid. The outlet 408 of the tank 303 allows the waste water to exit through the conduit 42. The pump 43 pumps the liquid in the conduit 42 into the conduit 41. The liquid will then continue to the filter 47. The filter 47 is a filter that separates the sediments, of a commercially available type. This filter will separate coarse and fine particles. After filtration in filter 47 the liquid continues in conduit 48 to filter 49. Filter 49 is a filter for the separation of metal ions. Filter 49 may be a filter composed of a bed of metal particulate matter material. The material of the metal particles is chosen from metals having favorable oxidation-reduction potentials relative to the oxidation-reduction potential of metal ions in the wastewater to establish conditions for spontaneous oxidation and reduction reactions with metal ions. The metal particle filter is described in US 4,642,192. After filtration in filter 47 and filter 49 the discarded liquid is now depleted of particles and metal ions. The residual liquid continues in conduit 403 to be disposed of in a landfill or into a tank (not shown) to be subsequently disposed of in a landfill.

Tank 303 is open at the top. After the waste liquid tank 303 is drained, the material floating on the surface of the waste liquid along with the material deposited on the bottom 406 of the tank 303 can be collected manually by wiping it with a cloth or the like. This material can then be disposed of safely.

If the liquid is not dangerous, it is not necessary to follow the procedure described above. Non-hazardous liquid can be disposed of into a landfill by opening valve 409.

The scheme in Figure 4a is suitable for processing liquids that have a high amount of solids. Tank 303 is then used as a settling tank for solids and therefore loading on sediment filter 47 is avoided. Figure 4b shows an alternative scheme to the scheme in Figure 4a. In Figure 4b a tank 303 is used as a storage tank to store the waste liquid after the process. The scheme in Figure 4b is suitable for processing waste liquids with a low or moderate solids content. In Figure 4b similar parts are shown with the same reference numerals as in Figure 3 and Figure 4a. The residual liquid that leaves the bowl 36 as stream 304 is pumped by the pump 43 in the conduit 42. The liquid leaves the pump 43 in the conduit 41. After a similar process in filter 47 and filter 49 as shown in Figure 4a, the liquid continues in conduit 403 to tank 303. The liquid entering tank 303 is now devoid of particles and ions. Tank 303 will serve in this embodiment as a storage tank until it is suitable for releasing its contents into a landfill. The liquid is disposed of in a landfill by opening valve 409.

The post-processing or treatment method and the device and the collection method and collection device according to the present invention can be used independently of each other.

Figure 5 shows the collection device and the water treatment unit, installed on a mobile cart. The installation of the collector 3 together with the waste water treatment unit on the trolley 50 allows the invention to be practical in the service of aircraft engines at airports. While an engine is being washed the unit collects and treats the residual water. After executing the engine wash, the carriage is moved to the next engine of the aircraft, and so on. Installation on carriage 50, shown in Figure 5, is an example only. Any person skilled in the art can design the cart differently and still be within the scope of the invention. Similar parts are shown with the same reference numbers in Figure 2, Figure 3, and Figure

4.

The carriage 50 is composed of a frame 51. The frame 51 rests on a chassis (not shown for clarity) equipped with wheels 52. The droplet separator 31 is supported by the supports 53 installed on the frame 51. The

ES 2 343 409 T3 drop 302, the bucket (not shown for clarity), the tank 303, the pump 43, the filter 47 and the filter 49 are installed on the frame 51. According to this embodiment the tank 303 has a volume of 500 liters. A screen 55 on each left and right side of the carriage prevents the air housed in the residual liquid from escaping from the sides. A handle 56 allows the cart to be pulled by hand or pulled by a vehicle.

Figure 6 shows the carriage 50 according to the invention positioned for the operation of an engine 1 installed under the wing. As can be seen, there is no physical contact between the carriage 50 and the aircraft. The droplet separator 31 is adjustable in height, as indicated by arrows, by the adjustment means, which, for example, can be hydraulic, pneumatic or a chain-driven unit. The height adjustment of the droplet separator 31 allows the carriage to be positioned under the wing of the aircraft. The height adjustment of the droplet separator 31 allows the carriage to be used for different types of aircraft of different aircraft manufacturers and with different engines. According to one embodiment, the position of the droplet separator 31 can be adjusted relative to the motor 1 in a vertical, horizontal or lateral direction.

Figure 7 shows the carriage 50 equipped with a scissor-type lift 73 to raise the frame 51 into position to collect the residual washing water from a tail-mounted motor 71. According to one embodiment, the position of the frame 51 can be adjusted relative to the motor 71 in a vertical, horizontal, or lateral direction. The carriage 50 may also comprise a motor for driving the adjustment means for the droplet separator 31 and the scissor lift 73. There is no physical contact between car 50 and the plane. The use of the scissor lift 73 allows the carriage to be used for different types of aircraft from different aircraft manufacturers and with different engines.

Although specific embodiments have been shown and described herein for purposes of illustration and by way of example, it will be understood by those of ordinary skill in the art that the specific embodiments shown and described may be substituted for a wide variety of alternative and / or equivalent embodiments. without departing from the scope of the present invention. This application is intended to cover any of the adaptations or variations of the embodiments discussed therein. Accordingly, the present invention is defined by the words of the appended claims.