Producing ageing gas for exhaust gas after-treatment systems

Abstract

The invention relates to a process of producing ageing gas for ageing components for the after-treatment of exhaust gas in a burner which comprises a combustion chamber with at least one fuel injection nozzle and with a combustion gas supply system with means for generating swirl, wherein the swirl of the combustion air is set as a function of the selected combustion air ratio λ.

1 . A process of producing ageing gas for ageing components for the after-treatment of exhaust gas in a burner, the process comprising:
 a combustion chamber with at least one fuel injection nozzle and with a combustion gas supply system that can generate a swirl, characterised in that the swirl of the combustion air is set as a function of the selected combustion air ratio λ.   
     
     
         2 . The process according to  claim 1 , characterised in that the swirl of the combustion air is changed as a function of changes in the combustion air ratio λ during the production of ageing gas. 
     
     
         3 . The process according to  claim 1 , characterised in that, with a combustion air ratio of λ22 1 (lean/stoichiometric), the swirl of the combustion air is set to be lower and is set to be higher with a combustion air ratio of λ<1 (rich). 
     
     
         4 . The process according to  claim 1 , characterised in that the entire flow of the combustion air can be mass flow controlled. 
     
     
         5 . The process according to  claim 1 , characterised in that the combustion air is divided into an inner primary air flow and an outer secondary air flow, wherein the combustion air in the inner primary air flow is supplied with a swirl. 
     
     
         6 . The process according to  claim 5 , characterised in that the combustion air in the outer secondary air flow is supplied in a substantially swirl-free condition. 
     
     
         7 . The process according to  claim 1 , characterised in that the secondary air flow can be throttled, wherein the secondary air flow is throttled more particularly for achieving a combustion air ratio of λ<1 (rich). 
     
     
         8 . The process according to  claim 1  characterised in that an axial position of the burner flame inside the combustion chamber is detected and that, with the burner flame having moved to the rear, the swirl of the combustion air is increased and reduced when the burner flame has moved to the front. 
     
     
         9 . The process according to  claim 1 , characterised in that ageing gas is returned from the combustion chamber in the form of a sheath flow into the region of the fuel injection nozzle (primary ageing gas return). 
     
     
         10 . The process according to  claim 9 , characterised in that, when the secondary air flow is throttled, the primary ageing gas return flow is also reduced. 
     
     
         11 . The process according to  claim 1 , characterised in that to the ageing gas originally produced in the burner there is added conditioned ageing gas in the combustion chamber treatment and provides a secondary ageing gas return flow. 
     
     
         12 . The process according to  claim 11 , characterised in that the percentage of the conditioned ageing gas of the secondary ageing gas return flow is modified for the purpose of maintaining a predetermined ageing gas temperature. 
     
     
         13 . The process according to  claim 11 , characterised in that the conditioned ageing gas of the secondary ageing gas return flow in the burner is added in the form of an annular sheath flow. 
     
     
         14 . The process according to claim I characterised in that, for re-starting the combustion chamber, in order to simulate an overrun fuel cut-off, there is set a combustion air ratio λ<1 (rich) and a high degree of swirl of the primary air. 
     
     
         15 . The process according to  claim 1 , characterised in that, behind the burner and in front of the components for the after-treatment of exhaust gas, conditioned ageing gas is added to the ageing gas produced in the burner and provides a tertiary ageing gas return flow. 
     
     
         16 . The process according to  claim 15 , characterised in that oil and/or fuel and/or foreign gas and/or air is added to the conditioned ageing gas of the tertiary ageing gas return flow. 
     
     
         17 . The process according to  claim 1  characterised in that the fuel injection is controlled in cycles with a pre-pressure of at least 20 bar. 
     
     
         18 . The process of ageing components for the after-treatment of exhaust gas by subjecting same to ageing gas, characterised in that the ageing gas for treating the components for the after-treatment of exhaust gas is produced in accordance with  claim 1 . 
     
     
         19 . A burner for producing ageing gas for ageing components used for the after-treatment of exhaust gas, said burner comprising:
 a combustion chamber with a combustion chamber axis, at least one fuel injection nozzle and a combustion air supply line which is provided with means for generating swirl, characterised in that the means for generating swirl are adjustable in the sense of changing the swirl intensity.   
     
     
         20 . The burner according to  claim 19 , characterised in that an annular sheath or funnel ( 61 ) in the combustion air flow is positioned in front of the fuel injection nozzle ( 31 ), which sheath or funnel ( 61 ) divides the combustion air flow into an inner primary air flow and an outer secondary air flow, wherein swirl is generated in the primary air flow. 
     
     
         21 . The burner according to  claim 20 , characterised in that the swirl is generated only in the primary air flow. 
     
     
         22 . The burner according to  claim 19 , characterised in that the swirl generating means comprise circumferentially distributed pivotable swirl blades ( 62 ) positioned on axes arranged radially relative to the combustion chamber axis. 
     
     
         23 . The burner according to  claim 19 , characterised in that in the burner there are provided means for controlling the volume flow of the combustion air flow. 
     
     
         24 . The burner according to  claim 23 , characterised in that the means for controlling the volume flow of the combustion air flow are arranged annularly in the secondary air flow. 
     
     
         25 . The burner according to  claim 23 , characterised in that the means for controlling the volume of the combustion air flow comprise of a ring of adjustable apertured diaphragms ( 56 ), which ring is arranged concentrically relative to the fuel injection nozzle. 
     
     
         26 . The burner according to  claim 19 , characterised in that there are arranged means for detecting the axial position of the flame in the combustion chamber ( 11 ), more particularly one temperature sensor or a plurality of temperature sensors arranged along the length of the combustion chamber. 
     
     
         27 . The burner according to  claim 19 , characterised in that, in the combustion chamber ( 11 ), there is provided a concentrically arranged flame pipe ( 23 ) which ends in front of the combustion chamber ( 11 ) and which, near the fuel injection nozzle ( 31 ), comprises circumferentially distributed apertures ( 43 ) for the returning ageing gas of the primary ageing gas return flow. 
     
     
         28 . The burner according to  claim 27 , characterised in that the exit apertures ( 43 ) in the flame pipe ( 23 ) are positioned in a portion ( 42 ) of the flame pipe ( 23 ), which portion ( 42 ) is narrowed like a nozzle. 
     
     
         29 . The burner according to  claim 19 , characterised in that inside the burner sheath ( 12 ), there is positioned a mixing pipe ( 21 ) which is arranged concentrically relative to the combustion chamber axis and which, together with the burner sheath ( 12 ), forms an annular chamber ( 27 ) to which there is connected a supply port ( 26 ) for conditioned ageing gas, wherein the mixing pipe ( 21 ) extends beyond the length of the flame pipe ( 23 ) and, behind the end of the flame pipe ( 23 ), comprises circumferentially distributed exit apertures ( 22 ) for the conditioned ageing gas of the secondary ageing gas return flow. 
     
     
         30 . The burner according to  claim 19 , characterised in that the fuel injection nozzle ( 31 ) is supplied by a high-pressure injection valve which can be controlled in cycles. 
     
     
         31 . The burner according to  claim 30 , characterised in that the fuel injection nozzle ( 31 ) is combined with the high-pressure injection valve to form a unit and is arranged inside the swirl generating means. 
     
     
         32 . A system for ageing components for the after-treatment of exhaust gas by subjecting said components to an ageing gas produced in a burner, characterised in that there is provided a burner ( 11 ) according to  claim 16  to which the components for the after-treatment of exhaust gas are connected via an ageing gas pipeline ( 100 ). 
     
     
         33 . The system according to  claim 32 , characterised in that the supply port ( 26 ) is connected to a pipeline ( 98 ) for ageing gas which is produced in the burner ( 10 ) and subsequently conditioned. 
     
     
         34 . The system according to  claim 33 , characterised in that, in the pipeline ( 98 ), there is arranged an ageing gas recooling device ( 102 ). 
     
     
         35 . The system according to  claim 33 , characterised in that, in the pipeline ( 98 ), there is arranged a throttle flap ( 106 ) and a controllably driven compressor ( 107 ). 
     
     
         36 . The system according to  claim 33  characterised in that that the pipeline ( 98 ) is connected to a main ageing gas pipeline ( 100 ) behind the components for the after-treatment of exhaust gas or to an ageing gas bypass pipeline ( 114 ) in the bypass leading to the components for the after-treatment of exhaust gas. 
     
     
         37 . The system according to  claim 33 , characterised in that prior to the pipeline ( 98 ) for conditioned ageing gas being connected to the supply port ( 26 ), a branch pipeline ( 99 ) is branched off said pipeline ( 98 ) and ends behind the burner ( 10 ) in the main ageing gas pipeline ( 100 ). 
     
     
         38 . The system according to  claim 37 , characterised in that feeding pipelines ( 112 ,  113 ) for oil and/or fuel and/or foreign gas and/or air end in the branch line ( 99 ).