A process for producing high purity hydrogen is disclosed. Specifically, the process includes (1) partially oxidizing either a refinery offgas feedstock or a gaseous hydrocarbonaceous feedstock, which contains a major component which includes at least one C₁-C₃ hydrocarbon and which has an average molecular weight of up to about 30, to produce a synthesis gas mixture of carbon monoxide and hydrogen, (2) reacting the synthesis gas mixture with steam to convert the carbon monoxide into a raw gas mixture which primarily includes carbon dioxide and hydrogen, and (3) subjecting the raw gas mixture to pressure swing adsorption to purify the raw gas mixture, thereby producing high purity hydrogen and a reject gas mixture of impurities.

Process for producing high purity hydrogen

Novel procedures are described for the production of syngas fuel intermediates from abundantly available natural gas. The novel procedures include: (a) providing a double tubular hydrogen transfer reactor having an inner tubular wall defining a heated reaction zone containing a catalyst and an outer tubular wall defining an annular zone between the tubular walls, said inner tubular wall including a hydrogen semipermeable membrane portion adapted to permit diffusion of hydrogen therethrough from the reaction zone to the annular zone while being impervious to other gases, (b) passing through said catalytic reaction zone of a feedstock comprising a mixture of methane and oxygen or a mixture of methane and carbon dioxide or a mixture of methane, carbon dioxide and oxygen, (c) continuously removing from the reaction zone at least part of the hydrogen being formed by diffusion thereof through said hydrogen semipermeable membrane into said annular zone, (d) continuously removing diffused hydrogen from said annular zone and (e) continuously removing a product mixture of carbon monoxide and hydrogen from the reaction zone.

Process for producing syngas and hydrogen from natural gas using a membrane reactor

A pressure swing adsorption process is used to achieve intermediate product recovery by the introduction of a gas displacement step before, simultaneous with or subsequent to pressure equalization between beds of a multi-bed adsorption system. A cocurrent depressurization step is then employed to achieve intermediate product recovery. A portion of said intermediate product or of the more readily adsorbable component recovered from a bed advantageously being employed to provide displacement gas for another bed in the adsorption system.

Pressure swing adsorption with intermediate product recovery

The present invention concerns a process for producing ammonia synthesis gas from the reforming of hydrocarbons with steam in a primary reformer (1) equipped with a plurality of externally heated catalytic tubes and then in a secondary reformer (2) together with an oxidant gas. In this process, the reaction of said hydrocarbons with said steam in said primary reformer (1) is performed at an operating pressure of at least 45 bar in the catalytic tubes and a flow of essentially pure oxygen or oxygen-enriched air is added to said secondary reformer as oxidant gas for substantially reforming together with said all the hydrocarbons content of said product gas exiting the primary reformer (1). In the case essentially pure oxygen is used as oxidant gas, a flow of nitrogen is added downstream the secondary reformer (2) to reach a N2/H2 molar ratio corresponding to or close to the stoichiometric ratio for ammonia synthesis. This process allows to obtain high synthesis gas production capacities and lower investment and energy costs.

Process for producing ammonia synthesis gas

Carbon monoxide is recovered as the intermediate component of a reformer effluent containing hydrogen, carbon monoxide and carbon dioxide in a pressure swing adsorption system by the introduction of a gas displacement step before, simultaneous with or subsequent to pressure equalization between beds of a multi-bed adsorption system, with a cocurrent depressurization step being employed to recover said CO product. The carbon dioxide-rich countercurrent depressurization and/or purge effluent is recycled to the reformer for reaction with natural gas or other feed gas, with no carbon dioxide scrubbing step being employed before passage of the reformer effluent to the pressure swing adsorption system.

Reformer-pressure swing adsorption process for the production of carbon monoxide

In a pressure swing adsorption system for the purification of hydrogen to be used in an ammonia synthesis gas, nitrogen is employed as a purge gas at an elevated purge pressure. The hydrogen recovered at adsorption pressure contains about 20-25% nitrogen and is advantageous for use as said ammonia synthesis gas. The purge gas is expanded to generate power that can be used to compress air being passed to an air separation system. The nitrogen recovered therein can be employed as said purge gas, while the oxygen recovered can conveniently be employed in a hydrogen generation system used to form said hydrogen passed to the pressure swing adsorption system.

Process for the production of ammonia

Process and apparatus for the production of ammonia

The bed utilisation and the product yield, especially in pressure swing adsorption processes designed for high pressure applications, are improved in that the cocurrent pressure reduction is ended at a relatively high intermediate pressure level. Additional void volume gas is liberated from each main adsorber bed by partial countercurrent pressure reduction prior to the conventional countercurrent release. This additional gas is passed to an auxiliary bed, which can simultaneously release gas at its outlet end, as a result of which the auxiliary bed is depressurised by the intermediate pressure level in the cocurrent flow. The gas released in this manner is passed to the outlet end of one or more auxiliary beds and/or one or more main beds for pressure equalisation and/or flushing purposes. The auxiliary bed belongs to an adsorber bed auxiliary group, which includes fewer and smaller beds than the main bed system. The auxiliary beds are not subjected to a higher pressure than the intermediate pressure level.

Andrija Fuderer

Papers

Process for the production of ammonia

Process and apparatus for the production of ammonia

Process and apparatus for pressure swing adsorption