Process and plant for producing hydrocarbon products from a feedstock originating from a renewable source, where a hydrogen-rich stream and on off-gas stream comprising hydrocarbons is formed. A portion of the hydrogen-rich stream is used as a recycle gas stream in a hydroprocessing stage for the production of said hydrocarbon products, and another portion may be used for hydrogen production, while the off-gas stream is treated to remove its H.sub.2S content and used as a recycle gas stream in the hydrogen producing unit, from which the hydrogen produced i.e. make-up hydrogen, is used in the hydroprocessing stage. The invention enables minimizing natural gas consumption in the hydrogen producing unit as well as steam reformer size.

There is described a method for producing hydrogen and generating electrical power. A hydrocarbon fuel source is decomposed into hydrogen and carbon using a hydrocarbon dissociation reactor. The carbon is separated from the hydrogen in a carbon separator. Electrical power is generated from the separated carbon using a direct carbon fuel cell.

There is described a method for producing hydrogen and generating electrical power. A hydrocarbon fuel source is decomposed into hydrogen and carbon using a hydrocarbon dissociation reactor. The carbon is separated from the hydrogen in a carbon separator. Electrical power is generated from the separated carbon using a direct carbon fuel cell.

The invention relates to a process for producing synthesis gas (5) in which hydrocarbon (2) is decomposed thermally in, a first reaction zone (11) to hydrogen and carbon, and hydrogen formed is passed from the first reaction zone (Z1) into a second action zone (Z2) in order to be reacted therein with carbon dioxide (4) to give water and carbon monoxide. The characteristic feature here is that energy required for the thermal decomposition of the hydrocarbon is supplied to the first reaction zone (Z1) from the second reaction zone (Z2).

A process to decompose methane into carbon (graphitic powder) and hydrogen (H.sub.2 gas) without secondary production of carbon dioxide, employing a cycle in which a secondary chemical is recycled and reused, is disclosed.

The present invention comprises a process for producing hydrogen, wherein in a first stage hydrocarbons are decomposed into solid carbon and into a hydrogen-containing gaseous product mixture, the hydrogen-containing gaseous product mixture, which has a composition in respect of the main components CH4, N2, and H2 of 20% to 95% by volume H2 and 80% to 5% by volume CH4 and/or N2, is discharged from the first stage at a temperature of 50 to 300° C., and this is supplied at a temperature differing from this exit temperature by not more than 100° C. to an electrochemical separation process and, in this second stage, the hydrogen-containing product mixture is separated in the electrochemical separation process at a temperature of 50 to 200° C. into hydrogen having a purity of >99.99% and a remaining residual gas mixture.

A method for producing elemental carbon and hydrogen gas directly from a hydrocarbon (for example, natural gas or methane) using a chemical reaction or series of reactions. In an aspect, other materials involved such as, for example, elemental magnesium, remain unchanged and function as a catalyst.

A method for producing elemental carbon and hydrogen gas directly from a hydrocarbon (for example, natural gas or methane) using a chemical reaction or series of reactions. In an aspect, other materials involved such as, for example, elemental magnesium, remain unchanged and function as a catalyst.

The invention relates to a method for separating off and immobilizing carbon dioxide and/or carbon monoxide from an exhaust gas (18). In the method, a stoichiometric ratio of carbon dioxide to hydrogen, and/or of carbon monoxide to hydrogen, which is suitable for a methanation reaction is set by virtue of a corresponding quantity of hydrogen or alternatively carbon dioxide and/or possibly carbon monoxide being supplied, with an auxiliary gas (24), to the exhaust gas (18). Subsequently, a catalytic reaction is performed in which, as starting products, carbon dioxide and/or carbon monoxide and hydrogen are converted into methane and water. The methane is separated off from the product of the catalytic reaction and is subsequently split into carbon and hydrogen, wherein the carbon takes solid form. The split-off carbon is collected and disposed of.

The invention relates to a method for separating off and immobilizing carbon dioxide and/or carbon monoxide from an exhaust gas (18). In the method, a stoichiometric ratio of carbon dioxide to hydrogen, and/or of carbon monoxide to hydrogen, which is suitable for a methanation reaction is set by virtue of a corresponding quantity of hydrogen or alternatively carbon dioxide and/or possibly carbon monoxide being supplied, with an auxiliary gas (24), to the exhaust gas (18). Subsequently, a catalytic reaction is performed in which, as starting products, carbon dioxide and/or carbon monoxide and hydrogen are converted into methane and water. The methane is separated off from the product of the catalytic reaction and is subsequently split into carbon and hydrogen, wherein the carbon takes solid form. The split-off carbon is collected and disposed of.