Device and method for treating an exhaust gas containing particles
View Patent ↗A device for treating an exhaust gas containing particles includes: an exhaust gas line, an emission electrode and an electric supply line for the emission electrode. The electric supply line is at least partially surrounded by an electric insulator and the electric insulator has an outer diameter, the electric insulator extending from the exhaust gas line substantially in the direction of the longitudinal axis of the exhaust gas line. The outer diameter measures at most 20 mm in the terminal region towards the longitudinal axis.
1. A device ( 1 ) for treating an exhaust gas containing particles, comprising:
an exhaust gas line ( 6 ) having a longitudinal axis ( 13 );
an emission electrode ( 2 );
an electrical supply line ( 3 ) configured to supply electricity to the emission electrode ( 2 );
a counter electrode ( 7 ) arranged inside the exhaust gas line ( 6 );
an electrical insulator ( 4 ) arranged inside the exhaust gas line ( 6 ) and spaced apart, with respect to the longitudinal axis, from the counter electrode ( 7 ), the electrical insulator ( 4 ) having an external diameter ( 12 ), wherein the electrical supply line ( 3 ) is enclosed at least in sections by the electrical insulator ( 4 ),
wherein the electrical insulator ( 4 ) extends from the exhaust gas line ( 6 ) toward the longitudinal axis ( 13 ) in a direction orthogonal to a direction of the longitudinal axis ( 13 ) of the exhaust gas line ( 6 ),
wherein the external diameter ( 12 ) is at most 20 mm in an end region ( 14 ) of the electrical insulator ( 4 ) proximate the longitudinal axis ( 13 ), and
wherein a section of the electrical supply line ( 3 ) inside the exhaust gas line ( 6 ) and not enclosed by the electrical insulator ( 4 ) is oriented in the direction of the longitudinal axis ( 13 ) so as to project towards the counter electrode ( 7 ) such that application of electrical potential to the emission electrode ( 2 ) via the electrical supply line ( 3 ) generates an electric field between the emission electrode ( 2 ) and the counter electrode ( 7 ).
2. The device ( 1 ) as claimed in claim 1 , wherein the external diameter ( 12 ) of the electrical insulator ( 4 ) is at most 20 mm over its entire length ( 15 ).
3. The device ( 1 ) as claimed in claim 1 , wherein the electrical insulator ( 4 ) has a surface ( 5 ) against which the exhaust gas can flow, wherein the surface ( 5 ) is at most 500 mm 2 in size.
4. The device ( 1 ) as claimed in claim 3 , wherein the surface ( 5 ) is at least 50 mm 2 in size.
5. The device ( 1 ) as claimed in claim 1 , wherein:
the electrical supply line ( 3 ) forms an intersection line ( 10 ) with the electrical insulator ( 4 ) inside the exhaust gas line ( 6 ), and
a spacing ( 11 ) between the intersection line ( 10 ) and the exhaust gas line ( 6 ) is sufficiently large to prevent the occurrence of flashover during operation of said device at an applied voltage of 25 kV.
6. The device ( 1 ) as claimed in claim 5 , wherein the spacing ( 11 ) between intersection line ( 10 ) and exhaust gas line ( 6 ) is at least 15 mm.
7. The device ( 1 ) as claimed in claim 1 , wherein:
the electrical supply line ( 3 ) has a honeycomb body ( 9 ) through which the exhaust gas can flow, and
the electrical insulator ( 4 ) is arranged between the honeycomb body ( 9 ) and the exhaust gas line ( 6 ).
8. The device as claimed in claim 7 , wherein the honeycomb body ( 9 ) is held in the exhaust gas line by a plurality of electrical insulators.
9. A method for treating an exhaust gas containing particles, in which the exhaust gas flows past an emission electrode ( 2 ) in an exhaust gas line ( 6 ) and an electrical supply line ( 3 ) configured to contact of the emission electrode ( 2 ) is enclosed at least in sections by an electrical insulator ( 4 ) having a surface ( 5 ), wherein a counter electrode ( 7 ) is arranged inside the exhaust gas line ( 6 ) and a section of the electrical supply line ( 3 ) inside the exhaust gas line ( 6 ) and not enclosed by the electrical insulator ( 4 ) is oriented in the direction of a longitudinal axis ( 13 ) of the exhaust gas line ( 6 ) so as to project towards the counter electrode ( 7 ), the method comprising:
a) applying a high voltage to the emission electrode ( 2 ) to generate an electric field between the emission electrode ( 2 ) and the counter electrode ( 7 ) and a corona discharge;
b) causing the exhaust gas to flow against the surface ( 5 ) of the electrical insulator ( 4 );
c) depositing particles on the surface ( 5 ); and
d) combusting the deposited particles on an area of the surface ( 5 ) at most 500 mm 2 in size.
10. The method as claimed in claim 9 , wherein step d) further comprises increasing the applied high voltage.