Exhaust gas apparatus and method for the regeneration of a nox trap and a particle filter

Abstract

Exhaust gas apparatus for the cleaning of exhaust gas where the exhaust gas apparatus comprises an exhaust conduit section which is formed with at least two separate flow paths. Each flow path is provided with a particle filter for the removal of particulate matter from the exhaust gas, an NOx trap for the removal of NOx from the exhaust gas. The exhaust gas apparatus further comprises at least one cold flame vaporizer in which fuel is partially oxidized in preheated air to form a cold flame gas where the cold flame vaporizer is arranged in fluid communication with each of the flow paths in the exhaust conduit section such that the cold flame gas can flow through the particle filter and the NOx trap, and valve means for controlling the flow of cold flame gas from the cold flame vaporizer to each flow path in the exhaust conduit section. Thereby, both the particle filter and the NOx trap in at least one of the flow paths can be regenerated in a single operation. There is also provided a method for regenerating cleaning means for exhaust gas where the cleaning means comprises an NOx trap and possibly a particle filter.

1 . Exhaust gas apparatus for the cleaning of exhaust gas, the exhaust gas apparatus comprising an exhaust conduit section which is formed with at least two separate flow paths, each flow path being provided with
 a particle filter for the removal of particulate matter from the exhaust gas,   an NOx trap for the removal of NOx from the exhaust gas,   
       wherein the exhaust gas apparatus further comprises
 at least one cold flame vaporizer in which fuel is partially oxidized in preheated air by a cold flame such that 2-20% of the calorific value of the fuel is released, 
 
       whereby a cold flame gas is formed,
 the cold flame vaporizer is arranged in fluid communication with each of the flow paths in the exhaust conduit section such that the cold flame gas can flow through the particle filter and the NOx trap, and 
 one or more valves for controlling the flow of cold flame gas from the cold flame vaporizer to each flow path in the exhaust conduit section, whereby both the particle filter and the NOx trap in at least one of the flow paths can be regenerated in a single operation. 
 
     
     
         2 . Exhaust gas apparatus according to  claim 1 ,
 wherein the flow paths are formed by providing the exhaust conduit section as one conduit with one or more partitions such that two or more separate flow paths for the exhaust gas are formed in the exhaust conduit section.   
     
     
         3 . Exhaust gas apparatus according to  claim 1 ,
 wherein the flow paths are formed by providing the exhaust conduit section with at least two separate conduits through which the exhaust gas can flow.   
     
     
         4 . Exhaust gas apparatus according to  claim 1 ,
 wherein the at least one cold flame vaporizer is arranged outside the flow paths and that the cold flame vaporizer, is connected to each of the flow paths of the exhaust conduit section by fluid lines or conduits.   
     
     
         5 . Exhaust gas apparatus according to  claim 1 ,
 wherein the at least one cold flame vaporizer is arranged within the exhaust conduit section.   
     
     
         6 . Exhaust gas apparatus according to  claim 1 ,
 wherein the exhaust gas apparatus comprises one or more valve controlling the flow of exhaust gas through each of the flow paths of the exhaust conduit section.   
     
     
         7 . Exhaust gas apparatus according to  claim 1 ,
 wherein the exhaust gas apparatus comprises a fuel supply which is arranged in fluid communication with the cold flame vaporizer.   
     
     
         8 . Exhaust gas apparatus according  claim 1 ,
 wherein the exhaust gas apparatus comprises an air supply and a heat exchanger or electrical heater for preheating the air, the air supply being arranged in fluid communication with the cold flame vaporizer.   
     
     
         9 . Exhaust gas apparatus according to  claim 7  or  8 ,
 wherein the exhaust gas apparatus comprises one or more valve controlling the flow of fuel and preheated air to the cold flame vaporizer. 
 
     
     
         10 . Exhaust gas apparatus according to  claim 1 ,
 wherein, in each flow path, the NOx trap is arranged downstream of the particle filter.   
     
     
         11 . Exhaust gas apparatus according to  claim 1 ,
 wherein the exhaust gas apparatus comprises an oxidation catalyst arranged downstream of the particle filter and the NOx trap.   
     
     
         12 . Method for regenerating cleaning means for exhaust gas flowing through an exhaust conduit section of an exhaust gas conduit, the exhaust conduit section being formed with at least two flow paths for the exhaust gas, the cleaning means being provided in each of the flow paths and comprising
 a particle filter for the removal of particulate matter from the exhaust gas,   an NOx trap for the removal of NOx from the exhaust gas,   
       wherein the method comprises the following steps:
 providing a cold flame gas by partially oxidizing a fuel in preheated air in a cold flame such that 2-20% of the calorific value of the fuel is released, the released heat being used to evaporate the fuel thereby forming the cold flame gas, 
 letting the cold flame gas flow through the particle filter and the NOx trap in at least one of the flow paths of the exhaust conduit section, thereby, in one operation, regenerating both the particle filter and the NOx trap in said at least one flow path. 
 
     
     
         13 . Method according to  claim 12 ,
 wherein the method further comprises the step of providing one or more valves for separately controlling the flow of cold flame gas from the cold flame vaporizer into each flow path of the exhaust gas conduit.   
     
     
         14 . Method according to  claim 12 ,
 wherein the method further comprises the step of providing a fuel supply arranged in fluid communication with the cold flame vaporizer, and an air supply and a heat exchanger or electrical heater for the preheating of the air, the air supply being arranged in fluid communication with the cold flame vaporizer.   
     
     
         15 . Method according to  claim 14 ,
 wherein the method further comprises the step of providing one or more valves for controlling the flow of fuel and preheated air to the cold flame vaporizer.   
     
     
         16 . Method according to  claim 12 ,
 wherein the method further comprises the step of arranging, in each flow path in the exhaust conduit section, the NOx trap downstream of the respective particle filter.   
     
     
         17 . Method according to  claim 12 ,
 wherein the method further comprises the step of arranging an oxidation catalyst in the exhaust conduit section downstream of the particle filter and the NOx trap.   
     
     
         18 . Method for regeneration of a NOx trap wherein a cold flame gas is flowed through the NOx trap such that the NOx trap is regenerated. 
     
     
         19 . Method for regeneration of a particle filter and a NOx trap in a single operation wherein a cold flame gas, which is formed by partially oxidizing a fuel in preheated air in a cold flame such that 2-20% of the calorific value of the fuel is released, the released heat being used to evaporate the fuel, thereby forming the cold flame gas, is flowed through the particle filter and the NOx trap such that the particle filter and the NOx trap are regenerated.