# US 8,784,515 B2 · In-situ coke removal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,515 B2 - Document ID: US8784515B2 - Status: Granted - Kind: B2 - Application number: 12/925,143 - Filed: 2010-10-14 - Published: 2012-04-19 - Granted: 2014-07-22 - Earliest claimed: 2010-10-14 - Assignees: Precision Combustion, Inc.; Honda Motor Co., Ltd. - Applicants: Subir Roychoudhury; Richard Mastanduno; David Spence; Jun Iwamoto; Go Motohashi - Inventors: Subir Roychoudhury; Richard Mastanduno; David Spence; Jun Iwamoto; Go Motohashi - Web page: https://patentgrep.com/patent/US8784515B2 ## CPC - C01B 3/386: Catalytic partial combustion - C01B 2203/0261: containing a catalytic partial oxidation step [CPO] - C01B 2203/10: Catalysts for performing the hydrogen forming reactions - C01B 2203/1205: Composition of the feed - C01B 2203/169: Controlling the feed - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract A process of catalytic partial oxidation of a hydrocarbon fuel with an oxidant to produce partially-oxidized reaction products including hydrogen, with simultaneous in-situ coke removal. The process involves feeding a hydrocarbon fuel and an oxidant to a reactor in a fuel-rich feed ratio; reacting the fuel and oxidant for a fuel-rich cycle-time so as to produce a partially-oxidized reaction product; varying the fuel feed, or the oxidant feed, or both feeds to produce a fuel-lean feed to the reactor; maintaining the fuel-lean feed for a fuel-lean cycle-time sufficient to reduce coke deposits while maintaining a substantially constant yield of partially-oxidized reaction product; and alternating between the fuel-rich and fuel-lean operating cycles. ## Claims ### Claim 1 A process of catalytic partial oxidation with in-situ coke removal, the process comprising: (a) feeding a hydrocarbon fuel into a reactor; (b) feeding an oxidant into the reactor, the hydrocarbon fuel and oxidant being fed in a fuel-rich feed ratio; (c) contacting the hydrocarbon fuel and oxidant in the reactor with a catalyst consisting essentially of a partial oxidation catalyst capable of converting the hydrocarbon into hydrogen and carbon monoxide, the contacting occurring at a temperature between 850° C. and 1,050° C. for a fuel-rich cycle time sufficient to produce hydrogen and carbon monoxide, and further wherein the fuel-rich cycle time is greater than 15 seconds but less than a time that would produce a temperature greater than 1,050° C. when the hydrocarbon fuel is shut off; (d) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to the reactor to produce a fuel-lean feed ratio of hydrocarbon fuel to oxidant; (e) maintaining the fuel-lean feed ratio at a temperature greater than 850° C. and less than 1,050° C. for a fuel-lean cycle-time greater than 100 milliseconds and less than 800 milliseconds so as to reduce coke deposits while maintaining a substantially constant yield of partially-oxidized reaction product; (f) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to the reactor so as to provide a fuel-rich feed ratio in the manner of steps (a) and (b); and reiterating process steps (c) through (f); and further wherein all process steps are conducted in the absence of co-fed water or steam. ### Claim 2 (depends on 1) The process of claim 1 wherein the oxidant comprises air, oxygen-enriched air, essentially pure oxygen, or a gas mixture comprising oxygen and nitrogen as main components. ### Claim 3 (depends on 1) The process of claim 1 wherein the hydrocarbon fuel is selected from the group consisting of gasoline, light oil (diesel fuel), biodiesel fuel, natural gas, ethane, propane, and alcohols. ### Claim 4 (depends on 1) The process of claim 1 wherein in process steps (a) and (b) an equivalence ratio of hydrocarbon fuel to oxidant fed to the reactor is greater than 1:1. ### Claim 5 (depends on 1) The process of claim 1 wherein the hydrocarbon fuel is fed to the reactor in a pulsed on-off cycle. ### Claim 6 (depends on 5) The process of claim 5 wherein the pulsed on-off cycle ranges from about 5 milliseconds to about 50 milliseconds. ### Claim 7 (depends on 6) The process of claim 6 wherein a duty ratio, which is the total time that the hydrocarbon fuel is fed to the reactor during the pulsed on-off cycle, ranges from 20 percent to 80 percent of the pulsed on-off cycle. ### Claim 8 (depends on 1) The process of claim 1 wherein in step (d) the feed of hydrocarbon fuel is decreased or stopped while the oxidant feed is maintained to produce a fuel-lean feed ratio of fuel to oxidant to the reactor. ### Claim 9 (depends on 1) The process of claim 1 wherein in step (d) the oxidant feed is increased while the feed of hydrocarbon fuel is maintained to produce a fuel-lean feed ratio of fuel to oxidant to the reactor. ### Claim 10 (depends on 1) The process of claim 1 wherein in step (d) the hydrocarbon fuel and oxidant are fed to the reactor in an equivalence ratio less than 1:1. ### Claim 11 (depends on 1) The process of claim 1 wherein the partial oxidation catalyst consists essentially of an ultra-short-channel-length metal mesh substrate having one or more noble metals deposited thereon, wherein the ultra-short-channel-length ranges from 25 microns to 500 microns. ### Claim 12 (depends on 11) The process of claim 11 wherein the hydrocarbon fuel is diesel fuel and the oxidant is air. ### Claim 13 (depends on 1) The process of claim 1 wherein a substantially constant yield refers to a percentage difference between maximum and minimum yields of partially-oxidized reaction product of less than 10 percent over the first 60 minutes of process operation. ### Claim 14 (depends on 1) The process of claim 1 wherein the fuel-rich cycle time is greater than 20 seconds and less than 10 minutes. ### Claim 15 In a catalytic partial oxidation process wherein a hydrocarbon fuel and an oxidant are fed into a reactor and contacted with a catalyst under catalytic partial oxidation conditions sufficient to produce hydrogen and carbon monoxide; the improvement comprising: (i) employing a catalyst consisting essentially of a partial oxidation catalyst capable of converting a hydrocarbon into hydrogen and carbon monoxide; (ii) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to produce a fuel-rich feed ratio of hydrocarbon fuel to oxidant to the reactor; and maintaining the fuel-rich feed ratio at a temperature between 850° C. and 1,050° C. for a fuel-rich cycle-time sufficient to produce hydrogen and carbon monoxide, and further wherein the fuel-rich cycle time is greater than 15 seconds but less than a time that would produce a temperature greater than 1,050° C. when the hydrocarbon fuel is shut off; (iii) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to produce a fuel-lean feed ratio of hydrocarbon fuel to oxidant to the reactor; and maintaining the fuel-lean feed ratio at a temperature greater than 850° C. and less than 1,050° C. for a fuel-lean cycle-time greater than 100 milliseconds and less than 800 milliseconds so as to remove coke deposits and to maintain a substantially constant yield of partially-oxidized reaction product; and (iv) reiterating process steps (i) to (iii) throughout the process; and further wherein the aforementioned process steps are conducted in the absence of co-fed water or steam.