Systems and methods for generating ammonia

Patent metadata

Field	Value
Publication number	US-11753979-B2
Application number	US-201917636928-A
Country	US
Kind code	B2
Filing date	Aug 22, 2019
Priority date	Aug 22, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

An ammonia generating apparatus comprises a housing comprising a first end wall on which a reductant injector configured to insert a reductant into the housing is mountable. A heating coil assembly is disposed within the housing. A first end of the heating coil assembly is located proximate to a location of the first end wall where a reductant injector tip of the reductant injector is located when the reductant injector is mounted on the first end wall. The heating coil assembly is configured to generate heat sufficient to thermolyze the reductant to generate ammonia and reaction byproducts, in response to an electric current being passed therethrough. A hydrolysis catalyst can be disposed downstream of the heating coil assembly for catalyzing hydrolysis of the reaction byproducts into ammonia.

First claim

What is claimed is:

1. An ammonia generating apparatus comprising:
a housing comprising a first end wall on which a reductant injector configured to insert a reductant into the housing is mountable; and
a heating coil assembly disposed within the housing, the heating coil assembly comprising:
a first heating coil having a first heating coil first end located proximate to the reductant injector and a first heating coil second end opposite the first heating coil first end, the first heating coil having a first cross-sectional width, and
a second heating coil located proximate to the first heating coil second end of the first heating coil and axially aligned with the first heating coil, the second heating coil having a second cross-sectional width larger than the first cross-sectional width,

wherein a first end of the heating coil assembly is located proximate to a location of the first end wall where a reductant injector tip of the reductant injector is located when the reductant injector is mounted on the first end wall, and wherein the heating coil assembly is configured to generate heat sufficient to thermolyze the reductant to generate ammonia and reaction byproducts, in response to an electric current being passed therethrough.

2. The ammonia generating apparatus of claim 1 , further comprising:
a hydrolysis catalyst disposed downstream of the heating coil assembly, the hydrolysis catalyst formulated to catalyze hydrolysis of the reaction byproducts into ammonia.

3. The ammonia generating apparatus of claim 1 , wherein:
a first heating coil first end of the first heating coil that is located proximate to the reductant injector is flared.

4. The ammonia generating apparatus of claim 3 , further comprising:
a reductant injector mount disposed in the first end wall of the housing, in which the reductant injector is mountable.

5. The ammonia generating apparatus of claim 4 , wherein:
the reductant injector mount comprises a cone shaped baffle extending from the reductant injector mount towards the first heating coil.

6. The ammonia generating apparatus of claim 5 , wherein:
an end of the baffle that is distant from the reductant injector extends into the flared first heating coil first end.

7. The ammonia generating apparatus of claim 1 , further comprising:
a heater disposed on an outer surface of the housing and configured to selectively heat the housing.

8. A reductant insertion system for inserting a reductant into an aftertreatment system, comprising:
a reductant insertion assembly;
a reductant injector disposed downstream of the reductant insertion assembly; and
an ammonia generating apparatus configured to be fluidly coupled to an exhaust conduit of an aftertreatment system, the ammonia generating apparatus comprising:
a housing comprising a first end wall on which the reductant injector is mounted,

wherein the reductant injector is configured to insert a reductant into the housing, and a heating coil assembly disposed within the housing, the heating coil assembly comprising:
a first heating coil having a first heating coil first end located proximate to the reductant injector and a first heating coil second end opposite the first heating coil first end, the first heating coil having a first cross-sectional width, and
a second heating coil located proximate to the first heating coil second end of the first heating coil and axially aligned with the first heating coil, the second heating coil having a second cross-sectional width larger than the first cross-sectional width,

wherein a first end of the heating coil assembly is located proximate to a reductant injector tip of the reductant injector, and
wherein the heating coil assembly is configured to generate heat sufficient to thermolyze the reductant to generate ammonia and reaction byproducts, in response to an electric current being passed therethrough.

9. The reductant insertion system of claim 8 , wherein:
the ammonia generating apparatus further comprises a hydrolysis catalyst disposed downstream of the heating coil assembly, the hydrolysis catalyst configured to catalyze hydrolysis of the reaction byproducts into ammonia.

10. The reductant insertion system of claim 8 , further comprising:
a controller operatively coupled to the heating coil assembly, the controller configured to selectively communicate the electric current to the heating coil assembly.

11. The reductant insertion system of claim 10 , further comprising:
a gas insertion assembly configured to insert air into the reductant injector so as to provide gas assisted delivery of the reductant into the housing, and wherein the controller is also operatively coupled to the reductant insertion assembly and the gas insertion assembly,
wherein the controller is further configured to:
determine whether a demand for reductant is present based on at least one operating parameter of an exhaust gas flowing through the aftertreatment system,
responsive to a demand for the reductant not being present, command the reductant insertion assembly to stop insertion of the reductant into the reductant injector, and
command the gas insertion assembly to continue inserting air into the reductant injector for a first time after commanding the reductant insertion assembly to stop reductant insertion so as to flush reductant out of the reductant injector.

12. The reductant insertion system of claim 8 , wherein:
a first heating coil first end of the first heating coil that is located proximate to the reductant injector is flared.

13. The reductant insertion system, of claim 12 , further comprising:
a reductant injector mount disposed in the first end wall of the housing, the reductant injector mounted in the reductant injector mount.

14. The reductant insertion system of claim 13 , wherein:
the reductant injector mount comprises a cone shaped baffle extending from the reductant injector mount towards the first heating coil.

15. The reductant insertion system of claim 14 , wherein:
an end of the baffle distal from the reductant injector extends into the flared heating coil first end.

16. The reductant insertion system of claim 8 , further comprising:
a heater disposed on an outer surface of the housing and configured to selectively heat the housing.

17. An aftertreatment system for treating exhaust gas produced by an engine, comprising:
an exhaust conduit configured to receive the exhaust gas;
a selective catalytic reduction system disposed in the exhaust conduit;
a bypass conduit fluidly coupled to the exhaust conduit, the bypass conduit configured to receive a portion of the exhaust gas flowing through the exhaust conduit from an upstream location of the exhaust conduit and return the portion of the exhaust gas to the exhaust conduit at a downstream location of the exhaust conduit;
a first oxidation catalyst disposed in the bypass conduit;
a hydrolysis catalyst disposed in the bypass conduit downstream of the first oxidation catalyst;
a reductant injector coupled to the bypass conduit at a location between the first oxidation catalyst and the hydrolysis catalyst and configured to insert a reductant into the exhaust conduit between the first oxidation catalyst and the hydrolysis catalyst; and
a hydrocarbon insertion assembly configured to selectively insert hydrocarbons into the first oxidation catalyst causing the hydrocarbons to combust so as to increase a temperature of the exhaust gas to a first temperature sufficient to thermolyze the reductant and generate ammonia and reaction byproducts,
wherein the hydroly

Assignees

• Cummins Emission Solutions Inc

Inventors

• Chiruta Mihai
• Johnson Samuel
• Morgan Tiffany D
• Mavroudis George Eugene
• Moreno Luis N

Classifications

• F01N3/2066 Primary

  Selective catalytic reduction [SCR] · CPC title

• F01N3/28 Primary

  Construction of catalytic reactors · CPC title

• F01N2610/01

  the substance being catalytic material in liquid form · CPC title

• F01N2610/02

  the substance being ammonia or urea · CPC title

• F01N2610/10

  the substance being heated, e.g. by heating tank or supply line of the added substance · CPC title