Method of production of coupled and ammonia gas from the natural gas and use of this process for the production of -urea

摘要

Process for linked production of olefins and of ammonia from natural gas. Dehydrated, desulphurised and decarbonated natural gas (1) is fractionated (S1). Methane (6) to which oxygen (12) is added passes through the oxidation reactor (U1) and receives the C2+ hydrocarbons (17), and the mixture passes through the pyrolysis reactor (U2). A gas stream containing olefins, hydrogen and optionally nitrogen (18) is collected. The stream (18) is subjected to various fractionations in order to obtain a fraction which is rich in hydrogen and possibly in nitrogen (8). Hydrogen to which nitrogen (8) is added passes through the ammonia synthesis reactor (U5). A gas stream containing ammonia (33) is collected. The stream (34) is fractionated (S9) to separate hydrogen and nitrogen from ammonia (35). Ammonia (36) to which carbon dioxide (37) is added passes through the urea synthesis reactor (U6). A stream containing urea (38) is collected. IMAGE