Patent ID: 7931712

Claim:
A method for converting natural gas and water into a gas mixture of carbon dioxide and hydrogen, comprising the following steps: combusting a portion of the natural gas with an oxidizing agent in a combustion chamber to generate heat, superheated steam, and a gas mixture of carbon dioxide, carbon monoxide, and hydrogen; steam reforming the gas mixture with additional superheated steam under steam-rich conditions in a second enclosure to transform a remaining portion of the natural gas into carbon dioxide, carbon monoxide, and hydrogen; water-gas-shifting any residual carbon monoxide into additional carbon dioxide and additional hydrogen by utilizing a water-gas-shift catalyst located in channels extending from a bottom of the second enclosure, thereby producing an effluent gas mixture that is predominantly carbon dioxide and hydrogen; boiling water in a top-to-bottom linear countercurrent heat exchanger in a first enclosure to generate the superheated steam by transferring heat released in the water-gas-shifting step, wherein as the water is gravitationally and thermally stratified from top to bottom with a top portion boiling into steam, the steam continues to rise and is additionally heated in the top-to-bottom linear countercurrent heat exchanger which comprises said channels located in a lower portion of the first enclosure and partially immersed in boiling water, and the second enclosure contained within an upper portion of the first enclosure; and utilizing the superheated steam produced as a reactant in the steam reforming step and the water-gas-shifting step to assist in reformation of the natural gas into carbon dioxide and hydrogen.