Decontamination system

Abstract

The invention relates to a gas decontamination system (1) for a gas turbine (90) test bench (80), this system (1) being intended to extract pollutants present in the gas stream displaced by this turbomachine (90) during operation. This decontamination system (1) comprises an upstream pipe (10) whose upstream end (11) is fluidically connected to the outlet port of the test bench (80), a gas cleaning device (20) in this upstream pipe (10), a fluid reservoir (30) whose inlet port (31) is fluidly connected to the downstream end (12) of the upstream pipe (10), and a downstream pipe (60) which is fluidly connected to the outlet port (32) of the reservoir (30) and which discharges downstream into the atmosphere. Figure 1

Description

Title of the invention: Decontamination system

[0001] The present invention relates to a decontamination system for a gas turbine test bench, for example a turbomachine.

[0002] Such a test bench comprises, from upstream to downstream (in the normal direction of airflow), an intake chamber, a turbomachine test chamber, and an exhaust stack. Air enters the test chamber through the intake chamber. The test chamber includes a turbomachine mounted on a thrust balance. In this test chamber, downstream of the turbomachine being tested, there is an exhaust duct comprising a tube that receives the exhaust gases escaping from the turbomachine during its test. The exhaust gases exit this tube and ascend into the exhaust stack.

[0003] Due to combustion in the turbomachine, the gases exiting the exhaust duct contain carbon dioxide. Furthermore, in certain configurations known as confined test benches, fine particles, sand, and corrosive gases (e.g., sulfur gas) are injected into the turbomachine to test its resistance under conditions similar to actual flight conditions in certain climates. These gases and particles are present in the stream ejected from the exhaust duct and subsequently flowing through the exhaust stack.

[0004] These gases and particles are pollutants, and the aim is to reduce their release into the atmosphere. To this end, a gas treatment device for these gas streams is placed in the exhaust stack. This treatment device includes filters with materials capable of adsorbing the gas, for example, carbon dioxide filters, and it includes electrostatic precipitators capable of capturing polluting particles.

[0005] Thus, in general, a gas decontamination system is known for a gas turbine test bench, this system being intended to extract pollutants present in the gas stream which is moved by the operating turbine.

[0006] However, existing treatment devices are not sufficiently effective in cleaning the gas stream exiting the gas turbine test bench. Consequently, there are emissions of pollutants, especially polluting particles and corrosive gas, which are excessive in relation to environmental protection standards. Description of the invention

[0007] The present invention aims to remedy these drawbacks.

[0008] The invention aims to provide a pollution control system for a gas turbine test bench in which the treatment of pollutants present in the gas stream displaced by This gas turbine in operation is carried out with optimal efficiency, and in the most economical way possible.

[0009] This goal is achieved thanks to the fact that the decontamination system includes an upstream pipe whose upstream end is intended to be fluidically connected to the outlet port of the test bench, a gas cleaning device which is located in the upstream pipe, a fluid reservoir whose inlet port is located above the liquid (L) contained in the reservoir and is fluidly connected to the downstream end of the upstream pipe, and a downstream pipe which is fluidly connected to the outlet port of the reservoir and which opens downstream into the atmosphere.

[0010] Thanks to these arrangements, the gas exiting the test bench is decontaminated more effectively. First, the gas is cleared of polluting particles by cleaning, which removes these particles into a liquid collected in the reservoir. Then, the passage of the gas over and in contact with this liquid promotes the dissolution of corrosive gases within it.

[0011] For example, the decontamination system includes a grid located in the tank downstream of the part of the tank intended to contain the liquid and upstream of the outlet, and intended to collect liquid droplets

[0012] For example, the grille is a paddle-type demisting device

[0013] For example, the decontamination system includes an oxygen supplier which is located in the tank and is intended to be located below the surface (S) of the liquid (L) contained in the tank, and a reagent supplier capable of reacting with oxygen and corrosive molecules present in the gas.

[0014] For example, the decontamination system includes a device for recycling the liquid contained in the tank, the recycling device being fluidly connected upstream to the tank by a first pipe and fluidly downstream to the tank by a second pipe.

[0015] For example, the cleaning device includes at least one liquid spray nozzle

[0016] For example, the cleaning device is fluidly connected to a pump which is fluidly connected to the reservoir and which is capable of supplying liquid to the cleaning device.

[0017] For example, the downstream pipe is equipped with a fan which is capable of circulating gases from upstream to downstream.

[0018] The invention also relates to a gas decontamination process for a gas turbine test bench which is intended to extract pollutants present in the gas stream which is moved by the operating turbine.

[0019] According to the invention, the method comprises the following steps (a) A fluid reservoir, an upstream pipe and a downstream pipe are provided, and the outlet port of the test bench and the inlet port of the reservoir are fluidly connected with the upstream pipe, the inlet port being located above the liquid L contained in the reservoir, the outlet port of the reservoir and the atmosphere are fluidly connected with the downstream pipe, such that the polluted gas from the test bench flows to the atmosphere through the upstream pipe, the reservoir and the downstream pipe. (b) The pollutant particles present in the polluted gas are moistened using a cleaning device located in the upstream pipeline so as to extract the particles from the polluted gas. (d) The polluted liquid is recovered from the tank in such a way as to dissolve the corrosive gas molecules present in the gas at the interface between the gas and said polluted liquid; (e) The unpolluted gas coming from the inlet pipe is evacuated through the outlet pipe.

[0020] For example, the process includes a step (c) in which a reagent is added to the contaminated liquid using a reagent supplier and such that, in step (d), oxygen is injected below the surface of the contaminated liquid in the tank using an oxygen supplier in order to create a chemical reaction between the corrosive pollutant present in the gas and the reagent and the oxygen

[0021] The invention will be better understood and its advantages will become more apparent upon reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which:

[0022] [Fig. 1] The [Fig. 1] is a perspective view of a gas turbine test bench with a pollution control system according to the invention.

[0023] [Fig.2] Fig.2 is a longitudinal cross-sectional view of the pollution control system of the [Fig.l]. Detailed description of the invention

[0024] In the description below, the terms "upstream" and "downstream" are defined with respect to the normal direction of gas and air flow in the test bench, the gas turbine, and the exhaust duct during normal operation of the invention. "Fluidically connected" means that the connection allows the flow of a fluid (liquid or gas).

[0025] The invention is described below in the case where the gas turbine is a turbomachine, but applies to any gas turbine.

[0026] Figure 1 represents a test bench 80 for a turbomachine 90 according to the invention. This test bench 80 comprises a building which includes, from upstream to downstream (in the normal direction of airflow during operation of the turbomachine 90, represented by a solid arrow F) an intake chamber 81, a test chamber 82 and an exhaust stack 83. In the case of a confined test bench, air enters the test chamber 82 through the intake chamber 81. The upstream end of the intake chamber 81 (on the left in the figure) is then closed by a door 815. Sand and / or other abrasive particles are injected into the intake chamber 81 by a first upstream injector 85 upstream of the turbomachine 90. Optionally, a corrosive gas (for example, containing sulfur) is injected by a second upstream injector 86 into the intake chamber 81. The test chamber 82 includes a turbomachine 90 which is mounted on a thrust balance 91 and is intended for testing.

[0027] The gas flow displaced by the turbomachine 90 passes through the exhaust stack 83 and then exits the building. For example, the exhaust stack 83 has a bend and a horizontal section, as illustrated in [Fig. 1]. Optionally, the exhaust stack 83 includes a treatment device 84 comprising filters with materials suitable for adsorbing polluting gas in the gas flow displaced by the turbomachine 90 and / or electrostatic precipitators suitable for absorbing polluting particles. For clarity, the test bench 80 is shown with a dashed line.

[0028] The decontamination system 1 according to the invention is now described. This system is designed to extract pollutants present in the gas stream exiting the exhaust stack 83. These pollutants are carbonaceous particles produced by combustion in the turbomachine, polluting particles introduced into the test bench 80 such as sand, and one or more corrosive gases. The decontamination system 1 is shown in [Fig. 1] and also in [Fig. 2], which shows this decontamination system 1 in longitudinal section. In the figures, the gas flow is indicated by arrows F.

[0029] The decontamination system 1 includes an upstream pipe 10 whose upstream end 11 is fluidically connected to the outlet of the exhaust stack 83. The decontamination system 1 includes a fluid reservoir 30 whose inlet 31 is fluidly connected to the downstream end 12 of said upstream pipe 10. In operation, the inlet 31 is located above the surface S of the liquid L contained in the reservoir 30, the reservoir 30 also containing the gas which flows above this liquid L. The decontamination system 1 includes a downstream pipe 60 which is fluidly connected to the outlet 32 ​​of the reservoir 30 and which opens downstream to the atmosphere. For example, this outlet 32 ​​is located in the upper wall of the reservoir 30.

[0030] The decontamination system 1 further comprises a gas cleaning device 20 located in the upstream pipeline 10. This cleaning device 20 sprays liquid that wets the polluting particles present in the gas flowing in The upstream pipe 10. Thus, these polluting particles are carried by gravity to the bottom (lower part) of the tank 30 to form a certain quantity of polluted liquid. For example, the cleaning device 20 includes one or more liquid spray nozzles 21. The gas then enters the tank 30 and flows over the polluted liquid L. A standing wave of turbulent flow, called the foam zone, is generated on the surface of the polluted liquid upon contact with the gas. The foam zone creates a high rate of liquid surface renewal. In addition, the gas temperature is reduced to the adiabatic saturation temperature, which allows for the treatment of hot gases (up to 1200 °C). Thus, corrosive molecules (e.g., sulfur compounds such as SO2) present in the gas are absorbed into the liquid.

[0031] The reservoir 30 contains liquid L in its lower part. Advantageously, the decontamination system 1 includes a recycling device 70 for the liquid contained in the reservoir 30. This recycling device 70 is capable of supplying liquid, for example water, to the reservoir 30 via a second pipe T2. This recycling device 70 is also capable of draining liquid from the reservoir 30 via a first pipe TL. The first pipe T1 is therefore upstream of the recycling device 70 and the second pipe T2 is downstream of the recycling device 70. The direction of liquid flow is illustrated in [Fig. 2] by black arrows.

[0032] The liquid initially present in the tank 30, and that which is supplied, if applicable, by the recycling device 70, is, for example, water. Advantageously, this liquid is water charged with a chemical reagent capable of reacting with the corrosive gas, and which in this case may be viscous. This reagent is introduced into this liquid by a reagent supply 45, either before or after the liquid is introduced into the tank 30. This reagent supply 45 is schematically illustrated by dashed lines in [Fig. 2] within the tank 30. The reagent is intended to react with the molecules of the corrosive gas to form a product that can then be easily extracted from the liquid, for example, because this product is anhydrous.

[0033] For example, if the polluted gas entering the upstream pipeline 10 contains the sulfur pollutant SO2, this reagent contains CaCO3 (calcium carbonate). The decontamination system 1 includes an oxygen supplier 40 located in the reservoir 30, which, during operation, is situated below, ideally immediately below, the surface of the polluted liquid contained in the reservoir 30. This oxygen can be supplied in the form of air. The CaCO3 particles react with the oxygen supplied by the injector 40 and with the SO2 to form calcium sulfate according to the reaction: 2 CaCO3 + 2 SO2 + O2 2 CaSO4 + 2 CO2

[0034] Calcium sulfate (CaSO4) is an anhydrous, solid, ionic mineral chemical compound. It therefore does not mix with water. Thus, it can be collected and drained at the first pipe T1. The liquid subsequently returned to the tank is therefore less contaminated.

[0035] Advantageously, the cleaning device 20 is fluidly connected to a pump 22 which is fluidly connected to the reservoir 30 and which is capable of supplying unpolluted liquid to the cleaning device 20. This connection can be at the level of the second pipe T2.

[0036] Advantageously, the decontamination system 1 includes a grid 50 located in the reservoir 30 downstream of the portion of the reservoir 30 intended to contain the liquid and upstream of the outlet orifice 32. The grid 50 collects any liquid droplets that may be carried along by the gas flow circulating towards the outlet orifice 32. For example, the grid 50 is a paddle-type defogging device. As shown in [Fig. 2], the grid 50 is located above the lower portion of the reservoir 30 where the contaminated liquid L is located. The gas flow rises from the inlet orifice 31 and passes through the grid 50.

[0037] Advantageously, the downstream pipe 60 is equipped with a fan 65 that circulates the gases from upstream to downstream. This facilitates the extraction of gases from the reservoir 30. This gas is air, or nearly pure air, since the gas exiting the reservoir through the outlet 32 ​​is decontaminated of gaseous and particulate pollutants.

[0038] The invention also relates to a decontamination method with the decontamination system as described above. In a step (a), a fluid reservoir 30, an upstream pipe 10, and a downstream pipe 60 are provided. The outlet port of the test bench 80 and the inlet port 31 of the reservoir 30 are fluidly connected by means of the upstream pipe 10, the inlet port 31 being located above the liquid L contained in the reservoir 30. The outlet port 32 of the reservoir 30 and the atmosphere are fluidly connected by means of the downstream pipe 60, such that the contaminated gas from the test bench flows through the upstream pipe 10, then through the reservoir 30, and then through the downstream pipe 60. For example, the reservoir 30 initially contains an uncontaminated liquid, for example, water.

[0039] In a step (b), the pollutant particles present in the polluted gas are moistened (wet) using a cleaning device 20 located in the upstream pipe 10 so as to extract the polluted particles from the polluted gas. These wet particles fall into the tank 30 by gravity.

[0040] In a step (d) the contaminated liquid is recovered from the reservoir 30 so as to dissolve the corrosive gas molecules present in the gas at the interface between the gas and the polluted liquid in a flow zone that forms at the interface between this gas and this polluted liquid.

[0041] In a step (e) the unpolluted gas coming from the inlet pipe is evacuated through the outlet pipe 60. Steps (d) and (e) occur simultaneously.

[0042] Advantageously, in step (c), a reagent is added to the contaminated liquid using a reagent supply 45. This mixing of the reagent with the contaminated liquid is carried out by adding the reagent to the tank 30 in step (a) or step (d). For example, the reagent is added to the liquid that is brought into the tank by the recycling device 70. Furthermore, in step (d), oxygen is injected (immediately) beneath the surface of the contaminated liquid in the tank 30 using an oxygen supply 40 in order to create a chemical reaction between the corrosive pollutant present in the gas and the reagent and the oxygen.

[0043] Advantageously, in a step (f) between step (b) and step (e), liquid droplets present in the gas flowing towards the outlet orifice 32 of the tank are recovered using a grid 50. This grid 50 is located in the tank 30 above the contaminated liquid and upstream of the outlet orifice 32. Thus, these droplets fall back into the contaminated liquid of the tank 30, which helps to clean the gas before it exits the tank 30.

Claims

Demands

1. A gas decontamination system (1) for a gas turbine (90) test bench (80), said system (1) being intended to extract pollutants present in the gas stream displaced by said turbomachine (90) during operation, said decontamination system (1) being characterized in that it comprises an upstream pipe (10) the upstream end (11) of which is intended to be fluidly connected to the outlet port of said test bench (80), a gas cleaning device (20) located in said upstream pipe (10), a fluid reservoir (30) the inlet port (31) of which is located above the liquid (L) contained in said reservoir (30) and is fluidly connected to the downstream end (12) of said upstream pipe (10), and a downstream pipe (60) that is fluidly connected to the outlet port (32) of said reservoir (30) and terminates downstream on the atmosphere.

2. Decontamination system (1) according to claim 1 comprising a grid (50) which is located in said tank (30) downstream of the part of said tank (30) intended to contain said liquid and upstream of said outlet orifice (32) and which is intended to collect liquid droplets.

3. Decontamination system (1) according to claim 2 such that said grid (50) is a paddle defogging device.

4. Decontamination system (1) according to any one of claims 1 to 3 wherein it comprises an oxygen supplier (40) which is located in said tank (30) and which is intended to be located below the surface (S) of the liquid (L) contained in said tank (30), and a reagent supplier (45) capable of reacting with the oxygen and the corrosive molecules present in said gas.

5. Decontamination system (1) according to any one of claims 1 to 4, comprising a recycling device (70) for the liquid contained in said tank (30), said recycling device (70) being fluidly connected upstream of said tank (30) by a first pipe (T1) and fluidly connected downstream of said tank (30) by a second pipe (T2).

6. Decontamination system (1) according to any one of claims 1 to 5 wherein the cleaning device (20) comprises at least one liquid spray nozzle (21).

7. Decontamination system (1) according to claim 6 wherein said cleaning device (20) is fluidly connected to a pump (22) which is fluidly connected to said reservoir (30) and which is capable of supplying liquid to the cleaning device (20).

8. Decontamination system (1) according to any one of claims 1 to 7 wherein said downstream pipeline (60) is provided with a fan (65) which is capable of circulating gases from upstream to downstream.

9. A gas decontamination method for a gas turbine (90) test bench (80) intended to extract pollutants present in the gas stream displaced by said turbine (90) during operation, said method being characterized in that it comprises the following steps: (a) A fluid reservoir (30), an upstream pipe (10), and a downstream pipe (60) are provided, and the outlet port of said test bench (80) and the inlet port (31) of said reservoir (30) are fluidly connected to said upstream pipe (10), said inlet port (31) being located above the liquid (L) contained in said reservoir (30), and the outlet port (32) of said reservoir (30) and the atmosphere are fluidly connected to said downstream pipe (60), such that the polluted gas from said test bench (80) flows to the atmosphere through said upstream pipeline (10), of said reservoir (30) and of said downstream pipeline (60);(b) The pollutant particles present in said polluted gas are moistened using a cleaning device (20) located in said upstream pipe (10) so as to extract said particles from said polluted gas; (d) The polluted liquid is recovered in said tank (30) so as to dissolve the corrosive gas molecules present in said gas at the interface between said gas and said polluted liquid; (e) The unpolluted gas coming from said inlet pipe (10) is discharged through said outlet pipe (60).

10. A gas decontamination process according to claim 9, wherein it comprises a step (c) in which a reagent is introduced into said contaminated liquid using a reagent supplier (45) and wherein, in step (d), oxygen is injected beneath the surface of said contaminated liquid into said tank (30) using a supplier (40) of oxygen in order to create a chemical reaction between the corrosive pollutant present in said gas and said reagent and oxygen.

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