Thermodenuder and method for removing semi-volatile material and semi-volatile particles from an aerosol

Abstract

A thermodenuder having a main tube with an outer wall, and a heater (23) arranged within the main tube. The heater is arranged in the center of a cross section through the main tube and is spaced apart from the outer wall of the main tube. The main tube has a main axis of extension, and the heater extends parallel to the main axis. The main tube has two openings that are arranged at opposing side faces of the main tube. A channel for an aerosol is arranged within the main tube between the heater and the outer wall and between the two openings. Furthermore, a method for removing semi-volatile material and semi-volatile particles from an aerosol is provided.

Claims

1. Thermodenuder comprising: a main tube with an outer wall, and a heater arranged within the main tube, wherein the heater is arranged in the center of a cross section through the main tube, the heater is spaced apart from the outer wall of the main tube, the main tube has a main axis of extension, the heater extends parallel to the main axis of extension of the main tube, the main tube has two openings which are arranged at opposing side faces of the main tube, and a channel for an aerosol is arranged within the main tube between the heater and the outer wall and between the two openings.

2. Thermodenuder according to claim 1, wherein an adsorbent material is arranged within the main tube between the outer wall and the heater.

3. Thermodenuder according to claim 2, wherein the adsorbent material is arranged spaced apart from heater.

4. Thermodenuder according to claim 2, wherein the adsorbent material comprises ceramic fiber.

5. Thermodenuder according to claim 2, wherein an inner tube is arranged within the main tube between the adsorbent material and the heater, where the inner tube is permeable for gases and the channel is arranged within the inner tube.

6. Thermodenuder according to claim 2, wherein a further channel is arranged between the outer wall and the adsorbent material.

7. Thermodenuder according to claim 1, wherein one of the openings is connected with a fitting.

8. Thermodenuder according to claim 1, wherein the main tube has the shape of a cylinder.

9. Thermodenuder according to claim 1, wherein the heater extends along at least 80% of the length of the main tube parallel to the main axis of extension of the main tube.

10. Thermodenuder according to claim 1, wherein the channel is in direct contact with the heater.

11. Thermodenuder according to claim 1, wherein one of the side faces of the main tube in which one of the openings is arranged is formed by a cap that is reversibly attached to the main tube.

12. Method for removing semi-volatile material and semi-volatile particles from an aerosol, the method comprising the steps of: providing a main tube with an outer wall, where a heater is arranged within the main tube, heating a volume surrounding the heater by the heater, and leading an aerosol through the main tube and through two openings of the main tube where the two openings are arranged at opposing side faces of the main tube, wherein the heater is arranged in the center of a cross section through the main tube, the heater is spaced apart from the outer wall of the main tube, the main tube has a main axis of extension, the heater extends parallel to the main axis of extension of the main tube, and a channel for the aerosol is arranged within the main tube between the heater and the outer wall and between the two openings.

13. Method according to claim 12, wherein semi-volatile material of the aerosol is evaporated within the main tube.

14. Method according to claim 12, wherein the main tube is heated from outside of the main tube.

15. Method according to claim 12, wherein a gas flow is provided through a further channel that is arranged between the outer wall and an adsorbent material that is arranged between the further channel and the channel.

Description

(1) In FIG. 1 a cross section through an exemplary embodiment of the thermodenuder is shown.

(2) In FIGS. 2 and 3 cross sections through further exemplary embodiments of the thermodenuder are shown.

(3) FIG. 1 shows a cross section through the thermodenuder 20 according to an exemplary embodiment. The thermodenuder 20 has a cylindrical shape. The cross section is a cut through the center of the thermodenuder 20 along the main axis of extension x of the cylinder. The main axis of extension x of the thermodenuder 20 is the vertical axis of the cylinder. This means, the side faces 34, 35 at the left and right of the thermodenuder 20 are the circular shaped areas of the cylinder that extend parallel to each other. The extent of the thermodenuder 20 along its main axis of extension x can be less than 1 meter.

(4) The thermodenuder 20 comprises a main tube 21 with an outer wall 22. The outer wall 22 establishes the cylinder shape of the thermodenuder 20. Thus, the main tube 21 has the shape of a cylinder. The outer wall 22 delimits the main tube 21. The outer wall 22 can comprise stainless steel or any other metal. The thermodenuder 20 further comprises a heater 23 which is arranged within the main tube 21. The heater 23 is arranged in the center of the main tube 21. In the cross section shown in FIG. 1 the heater 23 is arranged in the center surrounded by the outer wall 22. In a cross section in a plane which is perpendicular to the plane shown in FIG. 1 the heater 23 is arranged in the center of the main tube 21 and is completely surrounded by the outer wall 22. The heater 23 is not in direct contact with the outer wall 22 but spaced apart from the outer wall 22. The main tube 21 has a main axis of extension x which runs parallel to the main axis of extension x of the cylinder. The heater 23 extends parallel to the main axis of extension x of the main tube 21. The heater 23 can be a resistive heater 23 in form of an electrical conductor extending along most of the extent of the main tube 21. The heater 23 extends parallel to the main axis of extension x of the main tube 21.

(5) The main tube 21 has two openings 24, 25 which are arranged at opposing side faces 34, 35 of the main tube 21. The two openings 24, 25 are referred to as a first opening 24 and a second opening 25. The first opening 24 is arranged within the first side face 34 one of the side faces 34, 35 of the main tube 21. The second opening 25 is arranged within the second side face 35 of the side faces 34, 35 of the main tube 21. The first opening 24 is connected with a fitting 30. The fitting 30 completely fills the first opening 24. Through the fitting 30 an aerosol or a gas can be led into the main tube 21 which is shown by an arrow. The heater 23 is fixed to the fitting 30. The heater 23 is arranged at the center of the fitting 30. Around the heater 23 is a passage 33 for a gas or an aerosol within the fitting 30 so that an aerosol or a gas can be led through the fitting 30 into the main tube 21. The fitting 30 has an inlet 32 where an aerosol or a gas can be provided to the fitting 30.

(6) Within the main tube 21 a channel 26 for an aerosol is arranged between the heater 23 and the outer wall 22 and between the two openings 24, 25. The channel 26 extends from the passage 33 within the fitting 30 to the second opening 25. This means, the channel 26 extends between the two openings 24, 25. Furthermore, the channel 26 is adjacent to the heater 23. This means, the channel 26 is in direct contact with the heater 23.

(7) Within the main tube 21 an adsorbent material 27 is arranged between the outer wall 22 and the heater 23. The adsorbent material 27 can comprise activated carbon. Furthermore, the adsorbent material 27 is arranged spaced apart from the heater 23 so that it is not in direct contact with the heater 23.

(8) The channel 26 is formed within an inner tube 28 that is arranged within the main tube 21 between the adsorbent material 27 and the heater 23. The inner tube 28 is permeable for gases and semi-volatile material. The inner tube 28 separates the adsorbent material 27 from the channel 26. The adsorbent material 27 fills the whole space between the inner tube 28 and the outer wall 22. The channel 26 fills the whole space within the inner tube 28 which is not occupied by the heater 23. Thus, the channel 26 is a cavity within the main tube 21 where an aerosol can pass through the main tube 21.

(9) With FIG. 1 the method for removing semi-volatile material and semi-volatile particles from an aerosol is described. According to the method the main tube 21 with the outer wall 22 is provided, where the heater 23 is arranged within the main tube 21. A volume surrounding the heater 23 is heated by the heater 23. In this way a temperature gradient is established which is shown by an arrow extending from the center of the main tube 21 to the outer wall 22. This means, the temperature in the vicinity of the heater 23 is higher than the temperature in the vicinity of the outer wall 22. Furthermore, an aerosol is led through the main tube 21 and through the two openings 24, 25 of the main tube 21. The aerosol is provided to the inlet 32 of the fitting 30 and led through the fitting 30 and the first opening 24 into the channel 26. Within the channel 26 the aerosol moves from the first opening 24 to the second opening 25. The aerosol is heated by the heater 23 and semi-volatile material and semi-volatile particles of the aerosol are evaporated within the main tube 21. The evaporated semi-volatile material and semi-volatile particles can be adsorbed by the adsorbent material 27. The remaining nonvolatile particles of the aerosol leave the main tube 21 through the second opening 25 which is shown by an arrow. In this way, semi-volatile material and semi-volatile particles are efficiently removed from the aerosol.

(10) After the thermodenuder 20 has been operated for a certain time it is necessary to remove the adsorbed semi-volatile material and semi-volatile particles from the adsorbent material 27. This can be done in one of the following ways.

(11) At first, it is possible to heat the main tube 21 from outside of the main tube 21. For this purpose an external further heater can be arranged adjacent to the outer wall 22. The further heater heats the adsorbent material 27 and the adsorbed semi-volatile material and semi-volatile particles are evaporated. The evaporated semi-volatile material and semi-volatile particles can leave the main tube 21 through the second opening 25. In this way, the adsorbent material 27 is regenerated or cleaned.

(12) At second, it is possible that the second side face 35 of the main tube 21 is formed by a cap 31 that is reversibly attached to the main tube 21. This means, the cap 31 can be removed so that the main tube 21 is open at one of its side faces 35. Once the cap 31 is removed the adsorbent material 27 can be taken out of the main tube 21 replaced by a new adsorbent material 27.

(13) A third possibility to remove semi-volatile material and semi-volatile particles from the adsorbent material 27 is described with FIG. 2.

(14) FIG. 2 shows a cross section through another exemplary embodiment of the thermodenuder 20. The thermodenuder 20 has the same setup as shown in FIG. 1 with the only differences that a further channel 29 is arranged between the outer wall 22 and the adsorbent material 27 and that a further opening 36 is arranged within the first side face 34. This means, in this case the adsorbent material 27 does not extend towards the outer wall 22. The further channel 29 fills the whole space between the adsorbent material 27 and the outer wall 22. The further channel 29 extends parallel to the channel 26. The further opening 36 is arranged adjacent to the further channel 29.

(15) For cleaning or regenerating the adsorbent material 27 a gas flow is provided through the further opening 36 and the further channel 29. The gas flows through the further channel 29 and the adsorbent material 27 which is shown by arrows. The temperature of the gas is higher than the temperature of the adsorbent material 27. Thus, the adsorbent material 27 is heated by the gas. In this way, semi-volatile material and semi-volatile particles adsorbed on or within the adsorbent material 27 are evaporated. The gas is further led from the adsorbent material 27 through the channel 26 out of the main tube 21. With this flow of gas the evaporated semi-volatile material and semi-volatile particles are transported from the adsorbent material 27 out of the main tube 21. In this way, the adsorbent material 27 is cleaned or regenerated.

(16) FIG. 3 shows a cross section through another exemplary embodiment of the thermodenuder 20. The thermodenuder 20 has the same setup as shown in FIG. 1 with the only difference that the thermodenuder 20 does not comprise the adsorbent material 27 and the inner tube 28. In this setup evaporated semi-volatile material and semi-volatile particles from the aerosol can adsorb at the outer wall 22 which has a lower temperature than the surroundings of the heater 23. In this way, semi-volatile material and semi-volatile particles can be removed from an aerosol.

REFERENCE NUMERALS

(17) 20: thermodenuder 21: main tube 22: outer wall 23: heater 24: first opening 25: second opening 26: channel 27: adsorbent material 28: inner tube 29: further channel 30: fitting 31: cap 32: inlet 33: passage 34: first side face 35: second side face 36: further opening x: main axis of extension