Ammonia gas generator and method for producing ammonia in order to reduce nitrogen oxides in exhaust gases
AssigneeAlzchem AG
InventorsChristian Gerhart, Thomas Sattelmayer, Plamen Toshev
Life of this patent
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Abstract
The invention relates to an ammonia gas generator for producing ammonia from an ammonia precursor substance as well as the use thereof in exhaust after treatment systems. The invention further relates to a method for producing ammonia gas to reduce nitrogen oxides in exhaust gases, in particular combustion gases from internal combustion engines such as diesel engines.
Claims23
An ammonia gas generator for generating ammonia gas from a solution of an ammonia precursor substance, comprising:
- a catalyst unit, which comprises a catalyst for decomposing and/or hydrolysing ammonia precursor substances into ammonia gas and a mixing chamber upstream from the catalyst in a flow direction, the catalyst being of a catalyst volume VKat and the mixing chamber being of a mixing chamber volume VMisch;
- an injection device for introducing the solution of the ammonia precursor substance into the mixing chamber;
- and,
- an outlet for the ammonia gas that is generated,
- the ammonia gas generator comprising an inlet for a carrier gas which generates a tangential carrier gas stream with respect to the solution of the ammonia precursor substance injected into the mixing chamber, wherein the catalyst unit comprises at least one hydrolysis catalyst, wherein the at least one hydrolysis catalyst is either:
- (1) a hydrolysis catalyst that is divided in at least two parts, wherein a first of the at least two parts in the flow direction is in the form of a heated catalyst heated by a heater and wherein a second of the at least two parts in the flow direction is in the form of an unheated catalyst;
- or
- (2) two hydrolysis catalysts arranged one behind the other, a first of the two hydrolysis catalysts being a heated catalyst heated by a heater and a second of the two hydrolysis catalysts being an unheated catalyst.
A method for generating ammonia as from a solution of an ammonia precursor substance by means of an ammonia gas generator comprising:
- a catalyst unit, which comprises a catalyst for decomposing and/or hydrolysing ammonia precursor substances into ammonia gas and a mixing chamber upstream from the catalyst in a flow direction, the catalyst being of a catalyst volume VKat and the mixing chamber being of a mixing chamber volume VMisch;
- an injection device for introducing the solution of the ammonia precursor substance into the mixing chamber;
- and,
- an outlet for the ammonia gas that is generated, the method comprising:
- introducing the solution of the ammonia precursor substance into the mixing chamber separately from a carrier gas;
- and
- introducing the carrier gas tangentially to the solution of the ammonia precursor substance, wherein the catalyst unit comprises at least one hydrolysis catalyst, wherein the at least one hydrolysis catalyst is either:
- (1) a hydrolysis catalyst that is divided in at least two parts, wherein a first of the at least two parts in the flow direction is in the form of a heated catalyst heated by a heater and a second of the at least two parts in the flow direction is in the form of an unheated catalyst;
- or
- (2) two hydrolysis catalysts arranged one behind the other, a first of the two hydrolysis catalysts being a heated catalyst heated by a heater and a second of the two hydrolysis catalysts being an unheated catalyst.
Dependencies are inferred from the claim text.