Reforming diesel fuel for NOx reduction
AssigneeGM Global Technology Operations LLC
InventorByong K. Cho
Life of this patent
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Abstract
The selective catalytic reduction of nitrogen oxides (especially NO and NO2) in exhaust from diesel and other lean burn engines is improved by use of a compact hyperplasma reactor for generating ozone and other highly oxidizing species in a stream of air. A portion of the ozone containing air stream is blown directly into the exhaust for oxidizing NO to NO2. The other portion of plasma treated air is used to fractionate and reform a volume of diesel fuel to produce low molecular weight hydrocarbons and oxidized hydrocarbons to be added to the exhaust as NO2 reductants in the catalytic reduction.
Claims11
A method of reducing nitrogen oxides, including NO and NO2, in an exhaust stream at a temperature above about 150° C., said method comprising:
- flowing ambient air through a nonthermal plasma reactor to generate a plasma reactor output stream comprising oxidizing constituents, including ozone, and residual air constituents;
- bubbling at least a portion of the plasma reactor output stream through a volume of liquid diesel fuel to strip a vapor portion of diesel fuel hydrocarbons from the liquid volume into the plasma reactor output stream and to produce a fractionated and reformed diesel fuel containing stream comprising hydrogen-carbon-oxygen containing molecules;
- adding the fractionated and reformed diesel fuel containing stream to said exhaust stream for the reduction of said nitrogen oxides.
A method of reducing nitrogen oxides, including NO and NO2, in an exhaust stream from a diesel engine at a temperature above about 150° C., the method comprising:
- flowing ambient air through a nonthermal plasma reactor to generate a plasma reactor output stream comprising oxidizing constituents including ozone, and residual air constituents;
- adding a first portion of said plasma reactor output stream to the exhaust stream for oxidation of NO to NO2;
- bubbling a second portion of the plasma reactor output stream through a volume of liquid diesel fuel to strip a vapor portion of diesel fuel hydrocarbons from the liquid volume into the plasma reactor output stream and to produce a fractionated and reformed diesel fuel containing stream comprising hydrogen-carbon-oxygen containing molecules;
- adding the fractionated and reformed diesel fuel containing stream to said exhaust stream for the reduction of said nitrogen oxides separately from the addition of the first portion of said plasma reactor output stream to the exhaust stream;
- and, thereafter
- contacting said exhaust stream with a reduction catalyst for nitrogen oxides.
A method of reducing nitrogen oxides, including NO and NO2, in an exhaust stream from a diesel engine for powering a vehicle, the exhaust being at a temperature above about 150° C., the method comprising:
- blowing ambient air through a tubular non-thermal plasma reactor to generate a plasma reactor output stream comprising oxidizing constituents including ozone, and residual air constituents;
- bubbling a first portion of the plasma reactor output stream through a volume of liquid diesel fuel to strip a vapor portion of diesel fuel hydrocarbons from the liquid volume into the plasma reactor output stream and to produce a fractionated and reformed diesel fuel containing stream comprising hydrogen-carbon-oxygen containing molecules;
- adding the fractionated and reformed diesel fuel containing stream to said exhaust stream for the reduction of said nitrogen oxides
- adding a second portion of said plasma reactor output stream to said exhaust stream for oxidation of NO to NO2, said ozone containing plasma being added to said exhaust stream separately from, and prior to, the addition of the fractionated and reformed diesel fuel containing stream;
- and, thereafter
- contacting said exhaust stream with a reduction catalyst for nitrogen oxides.
Dependencies are inferred from the claim text.