The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO.sub.2 as a working fluid may be configured for simultaneous hydrogen production. Beneficially, substantially all carbon arising from combustion in power production and hydrogen production is captured in the form of carbon dioxide. Further, produced hydrogen (optionally mixed with nitrogen received from an air separation unit) can be input as fuel in a gas turbine combined cycle unit for additional power production therein without any atmospheric CO.sub.2 discharge.

A process for producing syngas that uses the syngas product from an oxygen-fired reformer to provide all necessary heating duties, which eliminates the need for a fired heater. Without the flue gas stream leaving a fired heater, all of the carbon dioxide produced by the reforming process is concentrated in the high-pressure syngas stream, allowing essentially complete carbon dioxide capture.

A process for producing syngas that uses the syngas product from a partial oxidation reactor to provide all necessary heating duties, which eliminates the need for a fired heater. Soot is removed from the syngas using a dry filter to avoid a wet scrubber quenching the syngas stream and wasting the high-quality heat. Without the flue gas stream leaving a fired heater, all of the carbon dioxide produced by the reforming process is concentrated in the high-pressure syngas stream, allowing essentially complete carbon dioxide capture.

A system and method for producing hydrogen from hydrocarbon and steam, including a membrane reformer with multiple membrane reactors each having a tubular membrane. The bore of the tubular membrane is the permeate side for the hydrogen. The region external to the tubular membrane is the retentate side for carbon dioxide. A sweep gas flows through the bore to displace hydrogen in a direction countercurrent to flow of hydrocarbon and steam in the region external to the tubular membrane. The method includes discharging hydrogen as permeate with the sweep gas from the bore, and discharging carbon dioxide in the region external to the tubular membrane as retentate from the membrane reactor.

The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO.sub.2 as a working fluid may be configured for simultaneous hydrogen production. Beneficially, substantially all carbon arising from combustion in power production and hydrogen production is captured in the form of carbon dioxide. Further, produced hydrogen (optionally mixed with nitrogen received from an air separation unit) can be input as fuel in a gas turbine combined cycle unit for additional power production therein without any atmospheric CO.sub.2 discharge.

In a hydrocarbon-fed steam methane reformer hydrogen-production process and system, carbon dioxide is recovered in a pre-combustion context, and optionally additional amounts of carbon dioxide are recovered in a post-combustion carbon dioxide removal, to provide the improved carbon dioxide recovery or capture disclosed herein.

The present invention is directed to a method and system of purifying hydrogen supplied from a storage cavern, particularly to removing methane and other hydrocarbons from the hydrogen withdrawn from the cavern by using selective adsorption. The adsorbed impurities can be removed from the adsorbent by increasing the temperature, reducing the pressure, or a combination of both.

A method of using a feedstock gas reactor is described. A hydrocarbon, such as methane, is chemical decomposed in the feedstock gas reactor using heat of combustion generated from the combustion of a combustible gas. A mixed product stream is extracted from the feedstock gas reactor. The mixed product stream comprises hydrogen, carbon, and water. At least a portion of the one or more combustion product gases are vented from the combustion chamber. At least some of the carbon is activated using the vented one or more combustion product gases. At least some of the activated carbon is recycled to the feedstock gas reactor.

A plasma carbon sequestration system and method are disclosed, wherein in the plasma carbon sequestration system, a first channel and a second channel of a plasma reactor are each provided with a flow controller, the plasma reactor is connected to a high voltage via a high voltage electrode and grounded via a ground electrode, water, or hydrogen, or methane is mixed with carbon dioxide respectively, to be introduced into the plasma reactor in a predetermined proportion under the control of the flow controllers, and a condenser is connected to the plasma reactor to condense a conversion product, and reactants which are not completely reacted from the plasma reactor, and is selectively used for circulation in the plasma reactor, thereby realizing environment-friendly treatment without a catalyst by a room temperature plasma technology.

Processes and apparatuses for recovering a high purity carbon dioxide stream. A first separation zone that may include a cryogenic fractionation column provides the high-purity CO.sub.2 stream. A vapor stream from the cryogenic fractionation column is passed to a second separation zone to separate the CO.sub.2 from the other components. The second separation zone may include a pressure swing adsorption unit or a solvent separation unit. The second separation zone provides a hydrogen enriched gas stream that may be used in a gas turbine. The second stream from the second separation zone includes carbon dioxide and, after a pressure increase in a compressor, may be recycled to the first separation zone.