Casale

A process for the catalytic synthesis of a cracked gas (10) from ammonia (NH₃) comprising the following steps:(a) preheating and evaporation (2) of liquid ammonia (1) to obtain an ammonia gaseous stream (3);(b) catalytic cracking (5) of said ammonia gaseous stream (3) to yield a cracked gas (10) containing nitrogen, hydrogen, and unreacted ammonia;(c) cooling of said cracked gas (10) by exchanging heat at least with said liquid ammonia (1) and/or at least part (26) of a vaporized ammonia stream (8);(d) recovery (13) of at least part of said unreacted ammonia from the cracked gas of step (c) to obtain an ammonia-depleted stream (15) and an ammonia-enriched stream (14); wherein step (d) comprises:(d.1) selective adsorption of ammonia on at least one molecular sieve to obtain an ammonia-charged molecular sieve and said ammonia-depleted stream (15); and(d.2) desorption of ammonia performed by increasing a temperature of said ammonia-charged molecular sieve, and purging with a purge stream (7), to obtain said ammonia-enriched stream (14);(e) recirculation of at least a portion of the ammonia-enriched stream (14) as feed to step (b), optionally after pre-heating and evaporation.

The present invention relates to a process or plant (1) for the production of a raw synthesis gas (10) or of a hydrogen-containing product (20).Said process comprises the following steps: (I) provision of a hydrocarbon feedstock (2) comprising one or more heavy hydrocarbon(s) in an overall amount comprised from 5% to 70% molar; said one or more heavy hydrocarbon(s) being aliphatic and/or aromatic hydrocarbon(s), or mixtures of aliphatic and/or aromatic hydrocarbons, having a number of carbon atoms comprised from 2 to 30; (II) optional pre-treatment (41) of said hydrocarbon feedstock (2) by hydrogenation of any unsaturated heavy hydrocarbon(s) and/or by purification of any catalyst poison contained in said hydrocarbon feedstock (2) to obtain a pre-treated hydrocarbon feedstock (45); (III) adjustment of a steam to carbon (S/C) ratio of said hydrocarbon feedstock (2) of step (I) to a S/C ratio comprised from 1 to 3 to obtain a steam-adjusted feedstock (4); (IV) pre-reforming of the steam-adjusted feedstock (4) of step (II) to obtain a pre-reformed stream (6, 6', 6") containing methane produced by reforming of said heavy hydrocarbon(s); (V) adjustment of a steam to carbon (S/C) ratio of said pre-reformed stream (6, 6', 6") of step (III) to below 1 to obtain a steam-adjusted stream (7); (VI) partial oxidation (POx) of the steam-adjusted stream (7) of step (IV) in presence of pure oxygen or oxygen-enriched air (22) to obtain said raw synthesis gas (10); (VII) optionally posttreatment (11, 12) and purification (13) of the raw synthesis gas (10) of step (VI) to obtain said hydrogen-containing product (20).

A process for the catalytic synthesis of a cracked gas (30) from ammonia (NH₃) comprising the steps of:(a) preheating and evaporating (2) liquid ammonia (1) to obtain an ammonia gaseous stream (3);(b) subjecting said ammonia gaseous stream (3) to catalytic ammonia cracking (5, 7) in presence of heat to yield a cracked gas (30) containing nitrogen, hydrogen, and any unreacted ammonia;wherein step (b) comprises a catalytic gas-heated cracking (GHC) step (5) and a fired cracking step (7), said fired cracking step (7) being performed in a cracking furnace including a plurality of externally heated catalytic tubes, at least part of a fired cracked gas (8) of said fired cracking step (7) being a heat input of the catalytic GHC step (5).

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