# US 7,744,728 B2 · Apparatus for and method of producing hydrogen using microwaves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,728 B2 - Document ID: US7744728B2 - Status: Granted - Kind: B2 - Application number: 11/826,239 - Filed: 2007-07-13 - Published: 2009-01-15 - Granted: 2010-06-29 - Earliest claimed: 2007-07-13 - Inventors: Wei-Hsin Chen - Web page: https://patentgrep.com/patent/US7744728B2 ## CPC - C01B 3/342: {with the aid of electrical means, electromagnetic or mechanical vibrations, or particle radiations} - C01B 3/16: using catalysts - C01B 3/323: Catalytic reaction of gaseous or liquid organic compounds other than hydrocarbons with gasifying agents - C01B 2203/0233: the reforming step being a steam reforming step - C01B 2203/061: Methanol production - C01B 2203/065: using hydrotreating, e.g. hydrogenation, hydrodesulfurisation - C01B 2203/068: Ammonia synthesis - C01B 2203/0855: by electromagnetic heating - C01B 2203/1041: Composition of the catalyst - C01B 2203/1047: Group VIII metal catalysts - C01B 2203/1076: Copper or zinc-based catalysts - C01B 2203/1288: Evaporation of one or more of the different feed components - C01B 2203/16: Controlling the process - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract An apparatus for producing hydrogen by microwave includes a microwave heater, a reaction tube comprising a catalyst bed, a cap, an output unit and a microwave control box. A method of producing hydrogen using microwaves has steps of feeding gas and liquid, vaporizing the liquid to from a mixed gas and heating the mixed gas. A liquid and a gas are selected at predetermined ratios to form the mixed gas that reacts on the catalyst bed to from hydrogen. Microwaves allow the apparatus to be ready for production quicker and reduce space required by the apparatus. Heating the liquid and gas using microwaves is fast so has a good energy efficiency. ## Claims ### Claim 1 An apparatus for producing hydrogen by microwave comprising: a microwave heater comprising a housing being metal; a heating chamber being defined in the housing; and a magnetron being mounted in the housing to produce and guide microwaves towards the heating chamber; a reaction tube being mounted in the heating chamber of the microwave heater and having a tube body having a top end and a bottom end; a supporting layer being mounted in the tube body; a catalyst bed being mounted in the tube body on the supporting layer; and a thermal storage layer being mounted in the tube body on the catalyst bed; a cap being mounted in the microwave heater and comprising a connecting member having a gas inlet, a liquid inlet and a sensor mount which all communicate with the top end of the tube body of the reaction tube; an output unit comprising a mounting member being mounted on the housing of the microwave heater; and an outlet tube extending through the mounting member and communicating with the bottom end of the tube body of the reaction tube; and a microwave control box being connected electrically to the microwave heater and having a thermal sensor being mounted through the sensor mount and into the catalyst bed; a temperature setting unit; and a power controller being connected electrically to the thermal sensor, the temperature setting unit and the magnetron. ### Claim 2 (depends on 1) The apparatus for producing hydrogen by microwave as claimed in claim 1, wherein the cap further comprises a metal upper cover mounted around the connecting member and attached to the housing of the microwave heater. ### Claim 3 (depends on 2) The apparatus for producing hydrogen by microwave as claimed in claim 2, wherein the output unit further comprises a metal lower cover mounted around the mounting member and attached to the housing of the microwave heater. ### Claim 4 (depends on 3) The apparatus for producing hydrogen by microwave as claimed in claim 3, wherein the microwave control box further has a power display being connected electrically to the power controller to display the power of the magnetron; and a power switch selectively supplying power to the microwave heater. ### Claim 5 (depends on 1) The apparatus for producing hydrogen by microwave as claimed in claim 1, wherein the catalyst bed uses a granular catalyst comprising 86˜92 wt % ferric oxide, 6˜10 wt % chromium hemitrioxide, 0.1˜2.0 wt % chromium trioxide and 1.5˜2.1 wt % copper oxide. ### Claim 6 (depends on 1) A method of producing hydrogen by microwave comprising steps of feeding gas and liquid into an apparatus as claimed in claim 1, wherein a gas and a liquid are fed concurrently into the reaction tube of the apparatus as claimed in claim 1 respectively through the gas inlet and the liquid inlet of the cap; vaporizing the liquid, wherein the liquid and gas flow into the thermal storage layer of the reaction tube to vaporize liquid to form liquid vapor that mixes uniformly with the gas to form a mixed gas; and heating the mixed gas, wherein the mixed gas flows into the catalyst bed of the reaction tube and undergoes a hydrogen production reaction at a preset temperature reached and sustained by microwaves. ### Claim 7 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein the hydrogen production reaction is a water gas shift or stream reforming reaction. ### Claim 8 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein the reaction temperature is 180° C. to 550° C. ### Claim 9 (depends on 8) The method of producing hydrogen by microwave as claimed in claim 8, wherein gas is carbon monoxide and liquid is water. ### Claim 10 (depends on 9) The method of producing hydrogen by microwave as claimed in claim 9, wherein a volume flow rate ratio of carbon monoxide to water vapor is 1:1˜1:10 in the catalyst bed. ### Claim 11 (depends on 10) The method of producing hydrogen by microwave as claimed in claim 10 wherein the residence time of the mixed gas in the catalyst bed is more than 0.1 sec. ### Claim 12 (depends on 8) The method of producing hydrogen by microwave as claimed in claim 8, wherein gas is nitrogen as a carrier gas and liquid is a mixed liquid of methanol and water. ### Claim 13 (depends on 12) The method of producing hydrogen by microwave as claimed in claim 12, wherein the volume ratio of methanol to water is 2:1˜1:5. ### Claim 14 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein gas is nitrogen as a carrier gas and liquid is a mixed liquid of ethanol and water. ### Claim 15 (depends on 14) The method of producing hydrogen by microwave as claimed in claim 14, wherein the volume ratio of ethanol to water is 1:1˜1:10. ### Claim 16 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein gas is synthetic gas and liquid is water. ### Claim 17 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein gas is methane and liquid is water. ### Claim 18 (depends on 17) The method of producing hydrogen by microwave as claimed in claim 17, wherein the volume flow rate ratio of methane to water vapor is 1:1˜1:10 in the catalyst bed. ### Claim 19 (depends on 6) The method of producing hydrogen by microwave as claimed in claim 6, wherein the thermal storage layer is refractory wool or glass beads.