# US 10,502,109 B2 · Ammonia generation from engine exhaust at ambient conditions using water-gas shift and ammonia synthesis catalysts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,109 B2 - Document ID: US10502109B2 - Status: Granted - Kind: B2 - Application number: 15/677,873 - Filed: 2017-08-15 - Published: 2019-02-21 - Granted: 2019-12-10 - Earliest claimed: 2017-08-15 - Assignees: Cummins Emission Solutions Inc. - Applicants: Cummins Emission Solutions Inc. - Inventors: Christopher John Keturakis - Web page: https://patentgrep.com/patent/US10502109B2 ## CPC - F01N 3/0842: {Nitrogen oxides} - B01D 53/90: Injecting reactants - B01D 53/9431: {Processes characterised by a specific device} - B01D 53/9495: {Controlling the catalytic process} - F01N 3/021: by means of filters - F01N 3/035: with catalytic reactors - F01N 3/0878: {Bypassing absorbents or adsorbents} - F01N 3/106: {Auxiliary oxidation catalysts} - F01N 3/108: {Auxiliary reduction catalysts} - F01N 3/2073: {Means for generating a reducing substance from the exhaust gases} - F01N 13/009: {having two or more separate purifying devices arranged in series} - B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas} - F01N 2240/25: an ammonia generator - F01N 2410/00: By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device - F01N 2430/04: by adding non-fuel substances to combustion air or fuel, e.g. additives - F01N 2610/02: the substance being ammonia or urea - F01N 2610/04: the substance being hydrogen - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Systems and methods described herein relate to generating ammonia from engine exhaust instead of or in addition to using on-board storage tank(s) and/or doser(s) to provide the necessary chemical reagents for purification of the exhaust stream. Systems and methods for generating ammonia and/or hydrogen from engine exhaust in exhaust aftertreatment systems under ambient conditions comprise at least one water-gas shift (WGS) catalyst and at least one ammonia synthesis catalyst (AMS catalyst) positioned downstream of the WGS catalyst. The WGS catalyst is configured, using the engine exhaust gas as an input, to generate hydrogen used by the AMS catalyst as inputs to generate ammonia and/or hydrogen. The ammonia and/or hydrogen thus generated are used downstream in ammonia- and/or hydrogen-based selective catalytic reduction catalysts (SCR). ## Claims ### Claim 1 A method for treating exhaust gas in an aftertreatment system, the method comprising: receiving a quantity of exhaust gas from an engine, the quantity of exhaust gas containing a quantity of water, a quantity of nitrogen, and a quantity of carbon monoxide; generating a quantity of hydrogen from the quantity of water and the quantity of carbon monoxide using a water-gas shift catalyst; generating, using an ammonia synthesis catalyst, a quantity of ammonia using the quantity of hydrogen generated by the water-gas shift catalyst from the quantity of exhaust gas and the quantity of nitrogen from the quantity of exhaust gas, as an input; and feeding, by an insertion conduit, the quantity of ammonia, generated by the ammonia synthesis catalyst from the quantity of hydrogen generated by the water-gas shift catalyst, and the quantity of nitrogen from the quantity of exhaust gas to a selective catalytic reduction catalyst, wherein a water conversion ratio of the water-gas shift catalyst is not greater than 25%. ### Claim 2 (depends on 1) The method of claim 1, wherein the quantity of nitrogen gas from the quantity of exhaust gas flows through the water-gas shift catalyst, and wherein the method further comprises feeding the quantity of nitrogen gas to the ammonia synthesis catalyst and generating at least the quantity of ammonia at a nitrogen gas conversion ratio of not greater than 15%. ### Claim 3 (depends on 1) The method of claim 1, wherein the quantity of exhaust gas received from the engine is a portion of a total quantity of exhaust gas generated by the engine over a time period, and wherein the method further comprises: routing the quantity of exhaust gas, by the exhaust conduit, to the water-gas shift catalyst to generate the quantity of hydrogen gas; and introducing, by an exhaust re-combination conduit, the quantity of ammonia to the selective catalytic reduction catalyst by combining the quantity of ammonia with the total quantity of exhaust gas generated by the engine. ### Claim 4 (depends on 1) The method of claim 1, wherein the selective catalytic reduction catalyst is hydrogen-based, and wherein the method further comprises: capturing, by a hydrogen gas conduit, a quantity of excess hydrogen gas that remains unreacted by the ammonia synthesis catalyst when producing the quantity of ammonia; and introducing, by the hydrogen gas conduit, the quantity of excess hydrogen gas to the selective catalytic reduction catalyst, wherein the quantity of excess hydrogen gas is not greater than 1% in relation to a volume of product generated by the ammonia synthesis catalyst. ### Claim 5 (depends on 1) The method of claim 1, wherein the quantity of ammonia generated by the ammonia synthesis catalyst from the quantity of hydrogen generated by the water-gas shift catalyst is not greater than 2.5% in relation to a volume of product generated by the ammonia synthesis catalyst. ### Claim 6 (depends on 1) The method of claim 1, wherein the quantity of hydrogen generated by the water-gas shift catalyst is not greater than 5% in relation to a volume of product generated by the water-gas shift catalyst. ### Claim 7 (depends on 1) The method of claim 1, wherein the quantity of water in relation to the quantity of exhaust gas is not greater than 20%. ### Claim 8 (depends on 1) The method of claim 1, wherein the quantity of carbon monoxide in relation to the quantity of exhaust gas is not greater than 3%. ### Claim 9 (depends on 1) The method of claim 1, wherein the water-gas shift catalyst is a high temperature-shift catalyst, the method further comprising operating the water-gas shift catalyst at a temperature between 200 to 550 degrees Celsius. ### Claim 10 (depends on 1) The method of claim 1, wherein the water-gas shift catalyst is a low temperature-shift catalyst, the method further comprising operating the water-gas shift catalyst at a temperature between 100 to 300 degrees Celsius. ### Claim 11 (depends on 1) The method of claim 1, further comprising operating the ammonia synthesis catalyst at a temperature between 100 and 550 degrees Celsius and under atmospheric pressure between 0.5 and 3 atm. ### Claim 12 (depends on 1) The method of claim 1, further comprising: initially operating the ammonia synthesis catalyst at a temperature between 100 and 550 degrees Celsius and under atmospheric pressure between 0.5 and 3 atm; and progressively increasing the pressure while the ammonia synthesis catalyst is in operation such that the ammonia synthesis catalyst continues to generate at least the quantity of ammonia using the quantity of hydrogen, generated by the water-gas shift catalyst from the quantity of exhaust gas, and a quantity of nitrogen from the quantity of exhaust gas, as an input. ### Claim 13 (depends on 12) The method of claim 12, further comprising progressively reducing the temperature of the ammonia synthesis catalyst towards 20 degrees Celsius. ### Claim 14 An exhaust aftertreatment system comprising: an exhaust conduit structured to receive a quantity of exhaust gas from an engine, the quantity of exhaust gas containing a quantity of water, a quantity of nitrogen, and a quantity of carbon monoxide; a water-gas shift catalyst structured to generate at least a quantity of hydrogen from the quantity of water and the quantity of carbon monoxide, a water conversion ratio of the water-gas shift catalyst being not greater than 25%; an ammonia synthesis catalyst structured to generate at least a quantity of ammonia using the quantity of hydrogen generated by the water-gas shift catalyst and the quantity of nitrogen from the quantity of exhaust gas as an input; and an insertion conduit structured to feed the quantity of ammonia, generated by the ammonia synthesis catalyst from the quantity of hydrogen generated by the water-gas shift catalyst and the quantity of nitrogen from the quantity of exhaust gas, to a selective catalytic reduction catalyst. ### Claim 15 (depends on 14) The exhaust aftertreatment system of claim 14, further comprising an oxidation catalyst, wherein a first portion of the quantity of exhaust gas is routed to the ammonia synthesis catalyst to generate the quantity of ammonia and a second portion of the exhaust gas is routed to the oxidation catalyst, and wherein the quantity of ammonia is combined with the second portion of the exhaust gas such that a combined exhaust stream is created and fed into the selective catalytic reduction catalyst. ### Claim 16 (depends on 14) The exhaust aftertreatment system of claim 14, wherein the selective catalytic reduction catalyst is hydrogen-based, the system further comprising a hydrogen gas conduit configured to: capture a quantity of excess hydrogen gas that remains unreacted by the ammonia synthesis catalyst when producing the quantity of ammonia; and introduce the quantity of excess hydrogen gas to the selective catalytic reduction catalyst; wherein the quantity of excess hydrogen gas is not greater than 1% in relation to a volume of product generated by the ammonia synthesis catalyst. ### Claim 17 (depends on 14) The exhaust aftertreatment system of claim 14, wherein the ammonia synthesis catalyst is configured to operate at a temperature between 100 and 550 degrees Celsius and under atmospheric pressure between 0.5 and 3 atm. ### Claim 18 (depends on 17) The exhaust aftertreatment system of claim 17, wherein, while the ammonia synthesis catalyst is in operation, the temperature of the ammonia synthesis catalyst is progressively reduced towards 20 degrees Celsius. ### Claim 19 (depends on 18) The exhaust aftertreatment system of claim 18, further comprising a computer-readable storage media having computer-executable instructions embodied thereon that, when executed by at least one processor, cause the pressure to be progressively increased and the temperature to be progressively reduced as long as the ammonia synthesis catalyst continues to generate at least the quantity of ammonia per a pre-determined time interval. ### Claim 20 (depends on 14) The exhaust aftertreatment system of claim 14, wherein the pressure is progressively increased while the ammonia synthesis catalyst is in operation such that the ammonia synthesis catalyst continues to generate at least the quantity of ammonia using the quantity of hydrogen, generated by the water-gas shift catalyst from the quantity of exhaust gas, and a quantity of nitrogen from the quantity of exhaust gas, as an input.