Process for Producing Ammonia Synthesis Gas and a Method for Revamping a Front-End of an Ammonia Plant

摘要

A process for producing ammonia make-up synthesis gas and a procedure for revamping a front-end of an ammonia plant for producing ammonia make-up synthesis gas are disclosed, wherein the make-up synthesis gas is produced by means of steam reforming of a hydrocarbon gaseous feedstock; said front-end includes a primary reformer, a secondary reformer, a shift conversion section, a CO2 removal section and optionally a methanation section; a shell-and-tube gas-heated reformer is installed after said secondary reformer, and a portion of the available feedstock is reformed in the tubes of said gas-heated reformer, and heat is provided to the shell side of said gas-heated reformer by at least a portion of product gas leaving the secondary reformer, possibly mixed with product gas leaving the tubes of said gas-heated reformer.

主权项

1. A procedure for revamping a front-end of an ammonia plant, said front-end being arranged to produce ammonia synthesis gas containing hydrogen and nitrogen by steam reforming of a hydrocarbon gaseous feedstock, said front-end including a primary reformer, a secondary reformer or an autothermal reformer, a shift conversion section, a CO2 removal section and optionally a methanation section, said procedure including at least:
installation of a gas-heated reformer after said secondary reformer, said gas-heated reformer being a shell-and-tube heat exchanger having a tube side and a shell side, and providing a catalytic reforming of a first gas current passing in the tube side and indirect heating of said first gas current by a second current traversing the shell side, said first current including a portion of the available hydrocarbon feedstock, the remaining portion of said feedstock being directed to said primary reformer, and said second current comprising at least a portion of a product gas effluent from said secondary reformer or autothermal reformer.