The invention relates to an absorber column and to the use thereof for separation of unwanted, especially acidic, gas constituents, for example carbon dioxide and hydrogen sulfide, from a crude synthesis gas by absorption with an absorbent, especially under low load states of the absorber column in relation to the synthesis gas velocity. According to the invention, a defined concentration of carbon dioxide in the clean synthesis gas is established by mixing at least a portion of the absorbent regenerated by flash regeneration with the absorbent regenerated by means of hot regeneration prior to the recycling thereof into the absorber column.

Systems and methods are provided for performing hydrocarbon reforming within a reverse flow reactor environment (or another reactor environment with flows in opposing directions) while improving management of CO.sub.2 generated during operation of the reactor. The improved management of CO.sub.2 is achieved by making one or more changes to the operation of the reverse flow reactor. The changes can include using an air separation unit to provide an oxygen source with a reduced or minimized content of nitrogen and/or operating the reactor at elevated pressure during the regeneration stage. By operating the regeneration at elevated pressure, a regeneration flue gas can be generated that is enriched in CO.sub.2 at elevated pressure. The CO.sub.2-enriched stream can include primarily water as a contaminant, which can be removed by cooling while substantially maintaining the pressure of the stream. This can facilitate subsequent recovery and use of the CO.sub.2.

The present invention relates to a method for dehydrogenating an alkane, the method including: a step of feeding into dehydrogenation reactors a feed gas stream containing a hydrocarbon to be dehydrogenated, hydrogen, and steam and performing dehydrogenation, wherein the dehydrogenation step is repeated in five or more sets, the dehydrogenation reactors have two parallel-connected reaction material heaters configured to heat the feed gas stream which is fed into each of the dehydrogenation reactors, and the steam is fed separately to the individual reactors for five or more sets of dehydrogenation steps; and a step of cooling and compressing a production gas stream resulting from the previous step, quenching the compressed product gas stream by passage through a cooling box, separating and purifying the product gas stream having passed through the cooling box, and recovering a product.

A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

Methods and systems for producing hydrogen substantially without greenhouse gas emissions, the method including producing a product gas comprising hydrogen and carbon dioxide from a hydrocarbon fuel source; separating hydrogen from the product gas to create a hydrogen product stream and a byproduct stream; injecting the byproduct stream into a reservoir containing mafic rock; and allowing components of the byproduct stream to react in situ with components of the mafic rock to precipitate and store components of the byproduct stream in the reservoir.

Systems and methods are provided for using a high heat capacity gas as at least a portion of the diluent during the regeneration step of a reverse flow reactor process. Instead of using nitrogen or air as the primary diluent gas, CO.sub.2 and/or H.sub.2O can be added as diluent gas for the regeneration step in the reaction cycle. Increasing the heat capacity of the diluent gas provides a reduction in the peak temperature within the reactor relative to the amount of fuel combusted during regeneration. This can allow for a reduction in the volume of diluent used during regeneration and/or an increase in the amount of fuel used. Reducing the volume of diluent can reduce the pressure drop during regeneration, which can provide a corresponding reduction in the amount of compression required for recycle of the diluent. Increasing the amount of fuel can allow for a corresponding increase in the amount of endothermic reaction performed during the reaction step.

The invention relates to a process for the combined production of hydrogen and carbon dioxide from a hydrocarbon mixture, in which the residual gas of a PSA H.sub.2 (12) is separated by permeation in order to reduce the hydrocarbon content thereof and the hydrocarbon-purified gas is separated at a low temperature to produce a carbon dioxide-rich liquid (22).

A process and apparatus for producing syngas from low grade coal and from a biomass wherein the process includes (i) gasification of a mixture of low grade coal and biomass, (ii) reforming the gasified mixture, and (iii) removing CO.sub.2 from the gasified and reformed syngas mixture.

A process is disclosed for increasing hydrogen recovery in an integrated refinery and petrochemical complex in which natural gas is used as a co-purge gas in a pressure swing adsorption unit. This natural gas is recovered in tail gas from the pressure swing adsorption unit. This process is useful for refinery off-gas and partial oxidation feeds.

Embodiments of the invention are directed to methods, processes, and systems for safely and reliably purifying hydrogen from a gas mixture containing hydrogen and oxygen using a cryogenic separation method.