SOOT GENERATOR WITH AT LEAST 3 SUPPLY LINES

Description

[0001] The invention relates to an aerosol generator, in particular a soot generator, according to the preamble of claim 1. The invention further relates to a method for generating an aerosol, in particular a method for generating soot.

[0002] Particle-reducing components, such as filter systems and / or catalysts, are used to reduce particles from engine exhaust. The filter systems used today differ primarily in the type of regeneration (burning off the soot). Active regeneration refers to the targeted, time-limited burning off of soot, while passive regeneration refers to the continuous degradation of soot, ideally in dynamic equilibrium. Model soot and real soot are used to technically test filter efficiency and the reactivity of soot. Various particle measurement techniques are currently used to verify the legally limited particle emissions. These determine particle mass and particle number. Standardized particle aerosols are currently not used for validating, calibrating, and verifying these particle measurement techniques.

[0003] In addition to combustion engines, various soot generators are currently used to produce soot particles.

[0004] EP 0 353 746 A2 describes a device for generating soot particles by spark discharge at graphite electrodes. US Pat. No. 4,751,069 A describes a system for producing soot particles by cracking carbonaceous materials at high temperatures. EP 1 055 877 B1 describes a burner for generating soot particles that combusts a fuel gas and an oxidizing gas in a combustion chamber. A refinement of this burner is described in EP 1 590 408 B1. A further refinement is described in WO 2014 / 085941 A1, which describes the use of a liquid fuel to generate soot particles.

[0005] Document DE 10 2011 011 207 A1 discloses a burner for a furnace comprising a first feed for at least one fuel, a second feed surrounding the first feed and a third feed surrounding the second feed, wherein oxidizing agents are supplied via the second and third feeds.

[0006] Document WO 2005 / 026616 A1 discloses a method for thermal exhaust gas purification, wherein the exhaust gases are fed to a burner located in a closed combustion chamber and operated with fuel gas and an oxygen-containing reactant (combustion air), and the toxic substances of the exhaust gases are burned or thermally decomposed by the mixture of fuel gas and combustion air burning at high temperature.

[0007] A disadvantage of the known devices is that the chemical composition of the particles as well as the particle morphology, i.e. the size and nature of the particles of the aerosol produced, cannot be influenced or at least can only be influenced to a limited extent.

[0008] It is therefore an object of the invention to provide an improved device for generating model aerosols, in particular soot, which avoids the disadvantages of conventional techniques. The object of the invention is, in particular, to provide an aerosol generator, in particular a soot generator, which allows for a direct influence on the chemical composition and / or morphology of the particles generated. A further object is to provide a method for generating an aerosol or soot, which avoids the disadvantages of conventional methods.

[0009] These objects are achieved by devices and methods having the features of the independent claims. Advantageous embodiments and applications of the invention emerge from the dependent claims and are explained in more detail in the following description, with partial reference to the figures.

[0010] According to a first aspect of the invention, the above objects are achieved by an aerosol generator, in particular a soot generator, comprising a combustion chamber in which fuel can be combusted with an oxidizing agent in at least one flame generating soot particles, and a fluid supply device for supplying fuel and an oxidizing agent into the combustion chamber.

[0011] The fluid supply device is characterized in that the fluid supply device has at least three supply lines for a fluid, the outlet-side end sections of which run parallel, so that at least three different fluids, in particular gases, can be introduced into the combustion chamber unmixed and in a parallel inflow direction. The fluids, in particular gases, are thus fed separately into the combustion chamber and to the flame. The inflow direction is the mean flow direction of the fluid flow flowing out of the outlet of the supply line and entering the combustion chamber.

[0012] This arrangement of supply lines offers the advantage of allowing several different types of fuel gases and / or oxidizing gases and / or inert gases to be fed into a combustion chamber. The combination of at least three supply lines and a parallel inflow direction allows for a flexible combination and composition of the components of the gas mixture combustible in the flame to achieve a desired particle morphology and / or chemical composition of the particles.

[0013] According to a preferred embodiment, the end sections of the at least three supply lines can be arranged coaxially within one another. In other words, according to this embodiment, the end sections have different diameters and are arranged coaxially nested within one another. This enables a compact arrangement of the end sections of the supply lines in order to introduce the different gases into the combustion chamber at the same point, if possible, or at the point where the flame is generated.

[0014] According to an alternative embodiment, the end sections can be arranged parallel to one another. This embodiment can be manufactured with little effort, particularly when a large number of supply lines are involved. In an advantageous variant of this embodiment, the end sections are arranged parallel to one another, forming a line arrangement with the greatest possible packing density.

[0015] According to a preferred embodiment, the fluid supply device has at least four supply lines. According to this variant, for example, at least two different fuel gases, an oxidizing gas and another inert gas or reactive gas, can be introduced into the combustion chamber. A reactive gas is a gas containing so-called heteroatoms (non-carbon atoms), such as nitrogen, sulfur, or other elements. Due to their nature, these reactive gases can act as oxidizing agents (e.g., SO2, NO2) or as reducing agents (e.g., NH3, H2S, N2O). A variant of this embodiment therefore provides for the fluid supply device to have four or more supply lines.

[0016] A further advantageous variant of this embodiment provides for the fluid supply device to have seven supply lines. This variant offers even greater flexibility for adjusting the composition of the gas mixture burned in the flame. A further advantage is that, with seven supply lines, their seven parallel end sections can be arranged with the greatest possible packing density. For this purpose, the end sections are arranged parallel to one another, with one of the end sections being located centrally, while the six remaining end sections are evenly distributed around the circumference and arranged at the smallest possible distance from the centrally located end section.

[0017] It is also particularly advantageous if the outlets of the supply lines are at the same height with respect to the inflow direction, so that the gases are introduced into the combustion chamber as close to each other as possible and mix as simultaneously as possible.

[0018] According to the invention, a first of the supply lines is connected on the inlet side to a first fluid container (fuel container) containing a first fuel. Furthermore, a second of the supply lines is connected on the inlet side to a second fluid container (fuel container) containing a second fuel. The first fuel can be a first fuel gas, and the second fuel can be a second fuel gas different from the first fuel gas. Examples of such fuel gases are hydrogen (H2), propane (C3H8), or acetylene (C2H2).

[0019] A further advantageous possibility of an implementation according to the invention provides that a third of the supply lines is connected on the inlet side to a third fluid container containing an oxidizing gas. It is also possible to use one or more oxidizing gases with different oxygen contents, for example, air, oxygen, or ozone, which are each fed into the combustion chamber via separate supply lines. According to this variant, at least two supply lines of the fluid supply device are then each connected on the inlet side to a container containing an oxidizing gas, with different oxidizing gases being stored in the containers.

[0020] Furthermore, at least one of the supply lines can be connected on the inlet side to a fluid container containing a reactive gas. In this way, one or more different reactive gases can be introduced into the combustion chamber.

[0021] Furthermore, the aerosol generator can be designed such that at least one of the supply lines is connected on the inlet side to a fluid container containing a so-called inert gas. Inert gases are characterized by the fact that they do not participate directly in the combustion process. Possible inert gases include N2, CO2, or noble gases. In this way, one or more different inert gases can be introduced into the combustion chamber to influence the physicochemical boundary conditions of combustion and, consequently, the particle morphology.

[0022] Furthermore, the aerosol generator can have regulating means by which a fluid flow rate can be adjusted in each of the supply lines. The regulating means can, for example, be a valve arrangement such that each supply line has at least one valve by means of which a flow rate through the supply line can be adjusted. In this way, the mixing ratio of the supplied gases can be varied, thereby exerting a direct influence on the morphology (size and nature) of the generated particles as well as on the chemical composition of the particles.

[0023] For example, increasing the acetylene content in the fuel gas mixture leads to a higher carbon content in the fuel gas and thus to greater soot formation in the flame. Increasing the hydrogen content leads to a higher hydrocarbon content in the formed particles. The use of pure hydrogen results in a soot-free flame. In this case, particle emissions can be caused, for example, by other reactive or inert gas components, such as sulfur-containing particles from the use of SO2 and / or H2S.

[0024] According to a second aspect of the invention, a method for generating an aerosol, in particular a method for generating soot, is provided, in which at least one fuel and one oxidizing agent are supplied to a combustion chamber by means of an aerosol generator as disclosed in this document, and a soot particle generating flame, in particular a diffusion flame, is formed in the combustion chamber.

[0025] An advantageous variant provides that at least two fuel gases, at least one oxidizing gas and at least one reactive gas or inert gas are introduced into the combustion chamber by means of an aerosol generator with at least four supply lines.

[0026] The invention further relates to a method for checking or calibrating a particle measuring device, particle sensor, particle filter or particle catalyst, characterized in that for checking or calibrating such a device, an aerosol, in particular soot particles, is supplied to the device, which are generated by means of an aerosol generator as disclosed in this document or by means of a method as disclosed in this document.

[0027] The above-described preferred embodiments and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. They show: Figure 1 shows a schematic representation of a soot generator according to one embodiment of the invention; Figures 2A and 2B show a sectional view of an outlet-side end section of the fluid supply device according to a further embodiment of the invention; and Figure 3 shows a sectional view of an outlet-side end section of the fluid supply device according to a further embodiment of the invention.

[0028] Identical or functionally equivalent elements are designated by the same reference numerals in all figures.

[0029] Figure 1 shows schematically a cross section of an embodiment 1 of the soot generator according to the invention.

[0030] The Figure 1The soot generator shown comprises a combustion chamber 7 in which at least one fuel can be combusted with an oxidizing agent in at least one soot particle-generating flame 10. The combustion chamber 7 can be designed in a conventional manner and, for example, be formed by a cylindrical outer tube 6, at the lower end of which an end portion of a fluid supply device 2 projects into the combustion chamber 7.

[0031] Combustion gases, an oxidizing gas and, if necessary, other gases such as a reactive gas or inert gas can be introduced into the combustion chamber via the fluid supply device 2.

[0032] In the example shown, the fluid supply device has four supply lines 3.1, 3.2, 3.3, and 3.4. However, it is emphasized that the fluid supply device can also have a larger number n of supply lines.

[0033] The outlet-side end sections 4.1, 4.2, 4.3, and 4.4 of the supply lines 3.1, 3.2, 3.3, and 3.4 run parallel, with the outlets 9 of the supply lines being at the same height with respect to the inflow direction R. In this way, in the illustrated embodiment, four different gases can be introduced separately and in a parallel inflow direction into the combustion chamber 7. The inflow direction of the gases exiting the outlets 9 of the supply lines is indicated by the arrow labeled R.

[0034] The end sections 4.1, 4.2, 4.3 and 4.4 of the supply lines 3.1, 3.2, 3.3 and 3.4 are arranged coaxially nested, which is indicated by the dashed lines in Figure 1is shown. The supply line 3.4, for example, merges into a cylindrical inner pipe section 4.4, which runs coaxially and inside the pipe section 4.3 of the supply line 3.3. The supply line 3.2 merges into a pipe section 4.2, inside which the pipe section 4.3 runs. The supply line 3.1 merges into an outer pipe section 4.1, inside which the pipe section 4.2 runs.

[0035] Such a coaxially nested arrangement of the end sections of the supply lines is in the Figures 2A and 2B illustrated again, but for an embodiment with three supply lines. Figure 2A shows a top view of the outlets 9 of the end sections 4.1, 4.2 and 4.3, while Figure 2B shows a sectional view along the flow direction.

[0036] The inlet 13 of one of the supply lines is connected to a fluid container (not shown) in which an oxidant is stored, so that an oxidant stored therein can be fed into the combustion chamber 7 at a specific flow rate through the outlet 9 of the corresponding end section. The flow rate can be adjusted via a valve 5.

[0037] Accordingly, the inlets 13 of two further supply lines are each connected to different fuel containers, with different fuel gases being stored in the fuel containers. In this way, two different fuel gases can be fed into the combustion chamber 7. The flow rate in each supply line can in turn be adjusted via a valve 5.

[0038] The inlet of the fourth supply line is connectable or connected to a fluid container (not shown) in which a reactive gas or an inert gas is stored, so that a reactive gas or inert gas is fed into the combustion chamber 7 at a specific inflow rate through the outlet 9 of the corresponding end section. The inflow rate can in turn be adjusted via a valve 5.

[0039] The fluid or fuel containers can each be, for example, a gas cylinder in which a gas is stored under excess pressure. To regulate the flow rate, the valves 5 can be designed as reducing valves.

[0040] After ignition, a flame 10 forms above the outlets 9 of the supply lines 3.1 to 3.4, in which soot particles are formed by combustion of the fuel with the oxidizing gas.

[0041] By adjusting the inflow rates via the valves 5, the mixing ratio of the supplied gases can be varied and thus a direct influence can be exerted on the morphology (size and nature) of the generated particles as well as on the chemical composition of the particles. In this way, the combustion and thus the factors influencing particle formation can be varied independently of one another. If one of the supplied fuel gases is acetylene, for example, increasing the acetylene content in the fuel gas mixture leads to a higher carbon content in the fuel gas and thus to greater soot formation in the flame. If one of the supplied fuel gases is hydrogen, increasing the hydrogen content leads to a higher hydrocarbon content in the particles formed. The use of pure hydrogen leads to a soot-free flame. In this case, the particle emission can be caused, for example, by other reactive or inert gas components, e.g.B. sulfur-containing particles by applying SO2 and / or. The upper end 8 of the combustion chamber can be designed in a conventional manner. For example, an aerosol or soot removal line (not shown) with an opening into the combustion chamber, through which soot particles and / or aerosols formed in the combustion chamber can be removed, can be provided.

[0042] Figure 3 illustrates a further embodiment of the feed device, showing a plan view of the outlets 9 of the end section of the feed device opening into the combustion chamber. As in Figure 3As can be seen, a special feature of this embodiment is that the supply device has seven separate supply lines, the end sections of which are arranged parallel to one another, forming a line arrangement 12 with the greatest possible packing density. For this purpose, the end sections are arranged parallel to one another, with one end section being arranged centrally, while the six remaining end sections are evenly distributed around the circumference and arranged at the smallest possible distance from the centrally arranged end section.

[0043] Possible applications of the particles or aerosols include the validation, calibration, and / or calibration of particle measuring devices and particle sensors, as well as the testing and evaluation of filters and catalysts. By incorporating appropriate chemical components, the generated aerosol can also be used to age sensors, catalysts, and filters. The use of aerosols to measure reaction kinetics enables the development of descriptive and / or predictive simulation models. Kinetic studies of model aerosols are also essential for functional development to optimize filter loading models and regeneration strategies. List of reference symbols

[0044] 1Soot generator 2Fluid supply device 3.1 - 3.4Supply line 4.1 - 4.4End section of the supply line 5Valve 6Outer tube 7Combustion chamber 8Upper end of the combustion chamber 9Outlet of the supply lines 10Flame 12Parallel packed line arrangement 13Inlet of the supply line RInflow direction

Claims

1. An aerosol generator, preferably a soot generator, comprising a combustion chamber in which fuel can be burnt with an oxidising agent in at least one soot particle-generating flame; a fluid supply device for supplying fuel and an oxidising agent into the combustion chamber, wherein the fluid supply device comprises at least three supply lines whose end portions extend in parallel, so that at least three different types of fluids, preferably gases, can be introduced into the combustion chamber unmixed and in a parallel inflow direction, wherein a first of the supply lines is connected on the inlet side to a first fluid container containing a first fuel, preferably a first fuel gas; and characterised in that a second of the feed lines is connected on the inlet side to a second fluid container containing a second fuel, preferably a second fuel gas.

2. Aerosol generator according to claim 1, characterised in that the end portions of at least three feed lines are arranged coaxially one inside the other3. Aerosol generator according to claim 1, characterised in a) that the end portions are arranged parallel to one another; and / or b) that the end portions are arranged parallel next to one another with the configuration of a line arrangement with the greatest possible packing density.

4. Aerosol generator according to one of the preceding claims, characterised in a) that the fluid supply device comprises at least four supply lines; or b) that the fluid supply device comprises four supply lines; or c) that the fluid supply device comprises seven supply lines.

5. Aerosol generator according to one of the preceding claims, characterised in that the outlets of the supply line are located at the same height with respect to the inflow direction.

6. Aerosol generator according to one of the preceding claims, characterised in a) that a third of the feed lines is connected on the inlet side to a third fluid container containing an oxidising gas; and b) that a fourth of the supply lines is connected on the inlet side to a fourth fluid container containing a reactive gas or an inert gas.

7. Aerosol generator according to any of the preceding claims, characterised by a regulating means by means of which a fluid flow rate in each of the supply lines is adjustable.

8. Method for generating an aerosol, preferably a method for generating soot, in which at least one fuel and one oxidising agent are supplied to a combustion chamber by means of an aerosol generator according to one of the preceding claims and a flame generating soot particles, preferably a diffusion flame, is formed in the combustion chamber.

9. Method according to claim 8, characterised in that at least two combustion gases, at least one oxidising gas and at least one reactive gas or inert gas are introduced into the combustion chamber by means of an aerosol generator according to claim 4.

10. Method for checking or calibrating a particle measurement device, particle sensor, particle filter, or particle catalyst, characterized in that an aerosol generator according to one of claims 1 to 7 is used for checking or calibrating such a device in order to generate an aerosol, preferably soot particles, and wherein the aerosol generated by the aerosol generator is supplied to the device.