Process for the ammonia production

Abstract

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 2 to N 2 molar ratio in the range 2.5 to 3.

What is claimed is: 
     
         1 . A plant for the synthesis of ammonia from a hydrocarbon feedstock, comprising:
 a primary reforming section suitable for reforming a hydrocarbon feedstock with steam obtaining a first reformed gas,   an air-fired secondary reforming section suitable for secondary reforming of said first reformed gas, obtaining a raw gas product,   a purification section of said raw gas product obtaining a make-up synthesis gas,   a conversion section including a synthesis loop, for conversion of said make-up synthesis gas into ammonia,   wherein:   said primary reforming section is suitable to perform primary reforming at a temperature of at least 790° C. and pressure of at least 50 bar, and said primary reforming section includes a tube reformer with tubes filled of catalyst, and said tubes are made of an alloy chosen among the following:   GX45NiCrSiNbTi3525 or GX40NiCrSiNb3525 according to EN 10027 classification, or HP alloys, HP mod alloys, HP mod Microalloy, HP Nb Microalloy, HP microalloy, HK microalloy according to ASTM A-608 and ASTM A-297 classification.   
     
     
         2 . The plant according to  claim 1 , including a compressor for feeding air to the secondary reforming section, wherein said air compressor is of the integrally geared type.