Single stage denitration
AssigneeStudsvik, Inc.
InventorJ Bradley Mason
Life of this patent
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Abstract
A system and method is described having a single reaction vessel using superheated steam optionally augmented by oxygen for reducing nitrogen oxides present in a wide variety of organic compounds. Reduction takes place quickly when a steam/oxygen mixture is injected into a fluidized bed of ceramic beads. Reducing additives are metered into the reaction vessel and/or provide energy input to reduce nitrates to nitrogen. The speed of the fluidizing gas mixture agitates the beads that then help to break up solid wastes and to allow self-cleaning through abrasion thereby eliminating agglomerates, and the oxygen, when used, allows for some oxidation of waste by-products and provides an additional offset for thermal requirements of operation.
Claims31
A method for converting nitrogen oxides, said method comprising the steps of:
- providing a waste feed containing nitrate;
- heating a reaction vessel containing a bed to an operating temperature of at least 400° C. but below the volatilization temperature of any metal ions in said waste feed;
- injecting superheated steam, oxygen, reductants and waste material into said reaction vessel, wherein said superheated steam is injected at a velocity that agitates said waste material and elutriates fine solids from said bed;
- operating a portion of said bed in reducing conditions so that substantially all of said nitrate in said waste material is reduced at said operating temperature thereby eliminating substantially all of the nitrogen oxides present in such waste material and leaving an inorganic solid residue low in nitrates and a gaseous effluent low in nitrogen oxides.
A method for converting nitrogen oxides, said method comprising the steps of:
- heating a reaction vessel that contains a bed of inert beads to an operating temperature;
- injecting steam and waste materials or compounds into said reaction vessel, said steam is injected at a velocity that agitates said waste material and elutriates fine solids from said bed, said reaction vessel having a first portion, a second portion and a third portion;
- co-injecting oxygen with said steam such that said first portion is operated under oxidizing conditions;
- operating said second portion under reducing conditions;
- and
- injecting oxygen into said third portion such that it operates under oxidizing conditions.
A method for removing nitrogen oxides, said method comprising the steps of:
- heating a reaction vessel that contains a bed of inert beads to an operating temperature;
- injecting steam and waste materials or compounds into said reaction vessel, wherein said steam is injected at a velocity that agitates said waste material and elutriates fine solids from said bed, said reaction vessel having a first portion, a second portion and a third portion;
- co-injecting oxygen with said steam such that said first portion is operated under oxidizing conditions;
- and
- operating said second and third portions under reducing conditions.
A method for removing nitrogen oxides, said method comprising the steps of:
- heating a reaction vessel that contains a bed of inert beads to an operating temperature;
- injecting steam and waste materials or compounds into said reaction vessel, wherein said steam is injected at a velocity that agitates said waste material and elutriates fine solids from said ;
- bed, said reaction vessel having a first portion, a second portion and a third portion
- co-injecting oxygen with said steam such that said third portion is operated under oxidizing conditions;
- and
- operating said first and second portions under reducing conditions.
Dependencies are inferred from the claim text.