A multi-bed catalytic reactor, particularly for the synthesis of ammonia, wherein the beds have an annular shape, the first bed has L(1)*(V/V(1)) equal to or greater than 50 wherein L(1) is the slenderness ratio of the first bed which is calculated as the axial length over the radial width; V is the total volume of the beds of the reactor and V(1) is the volume of the first bed.

High purity hydrogen is produced by a steam reforming hydrogen production unit with at least one of a bayonet reactor for reforming steam and a hydrocarbon, a recuperative burner, and a regenerative burner such that the steam reforming unit produces little or no steam in excess of the steam reforming process requirements. High purity hydrogen is separated from the syngas exiting the reformer via a pressure swing adsorption unit and combined with high purity nitrogen from an air separation unit as feedstock to a Haber process ammonia synthesis unit. Compressors for the ammonia synthesis unit are driven by higher efficiency drivers than are possible using the low temperature steam conventionally exported from a steam reforming unit. Compression power requirements are reduced.

High purity hydrogen is produced by a steam reforming hydrogen production unit with at least one of a bayonet reactor for reforming steam and a hydrocarbon, a recuperative burner, and a regenerative burner such that the steam reforming unit produces little or no steam in excess of the steam reforming process requirements. High purity hydrogen is separated from the syngas exiting the reformer via a pressure swing adsorption unit and combined with high purity nitrogen from an air separation unit as feedstock to a Haber process ammonia synthesis unit. Compressors for the ammonia synthesis unit are driven by higher efficiency drivers than are possible using the low temperature steam conventionally exported from a steam reforming unit. Compression power requirements are reduced.

Process and plant for the synthesis of ammonia from a hydrocarbon feedstock, comprising: primary reforming with steam and air-fired secondary reforming wherein primary reforming is performed at a temperature and pressure of at least 790 C. and 50 bar, and secondary reforming is carried out substantially in absence of excess air, the so obtained make-up synthesis gas having a H.sub.2 to N.sub.2 molar ratio in the range 2.5 to 3.

Process and plant for the synthesis of ammonia from a hydrocarbon feedstock, comprising: primary reforming with steam and air-fired secondary reforming wherein primary reforming is performed at a temperature and pressure of at least 790 C. and 50 bar, and secondary reforming is carried out substantially in absence of excess air, the so obtained make-up synthesis gas having a H.sub.2 to N.sub.2 molar ratio in the range 2.5 to 3.

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 together with air in a secondary reformer (2) is characterized in that the reaction of said hydrocarbons with said steam in said primary reformer (1) is performed at an operating pressure of more than 35 bar in the catalytic tubes, in that air is added to said secondary reformer in excess over the nitrogen amount required for ammonia synthesis and in that the excess of nitrogen is removed downstream the secondary reformer preferably by cryogenic separation or by molecular sieves of the TAS or PSA type. This process allows to obtain high synthesis gas production capacities and lower investment and energy costs.

In a cooled axial/radial flow converter, in which process gas passes from an outer annulus via a catalyst bed to an inner center tube, the catalyst bed is divided into identical modules stacked on top of each other. The process gas reaches the catalyst through openings facing the outer annulus, passes axially down the catalyst bed of each module, leaves the module through collectors in the bottom thereof, and flows to the center tube. The catalyst bed is cooled by cooling panels, in which the process gas is pre-heated to the reaction temperature, while at the same time the heat of reaction is partly removed from the catalyst bed. The converter is especially suitable as ammonia converter.

In a cooled axial/radial flow converter, in which process gas passes from an outer annulus via a catalyst bed to an inner centre tube, the catalyst bed is divided into identical modules stacked on top of each other. The process gas reaches the catalyst through openings facing the outer annulus, passes axially down the catalyst bed of each module, leaves the module through collectors in the bottom thereof, and flows to the centre tube. The catalyst bed is cooled by cooling panels, in which the process gas is pre-heated to the reaction temperature, while at the same time the heat of reaction is partly removed from the catalyst bed. The converter is especially suitable as ammonia converter.

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 together with air in a secondary reformer (2) is characterized in that the reaction of said hydrocarbons with said steam in said primary reformer (1) is performed at an operating pressure of more than 35 bar in the catalytic tubes, in that air is added to said secondary reformer in excess over the nitrogen amount required for ammonia synthesis and in that the excess of nitrogen is removed downstream the secondary reformer preferably by cryogenic separation or by molecular sieves of the TAS or PSA type. This process allows to obtain high synthesis gas production capacities and lower investment and energy costs.

Process and plant for the synthesis of ammonia from a hydrocarbon feedstock, comprising: primary reforming with steam and air-fired secondary reforming wherein primary reforming is performed at a temperature and pressure of at least 790 C. and 50 bar, and secondary reforming is carried out substantially in absence of excess air, the so obtained make-up synthesis gas having a H.sub.2 to N.sub.2 molar ratio in the range 2.5 to 3.