| 摘要 |
Ammonia production comprising the steps of (a) providing a reaction stream 1 comprising carbon monoxide (CO) and hydrogen, e.g. by steam reforming of hydrocarbons with oxygen or air; (b) passing the reaction stream and steam 2 over a water gas shift (WGS) catalyst (e.g. alkali promoted copper-zinc alumina) in a shift reactor 3 to form a shifted gas mixture 4 depleted in CO and enriched in hydrogen; (c) passing the shifted gas mixture with oxygen or air 5 over a selective oxidation catalyst (e.g. 15 wt% Pt and 0.1-1.0 wt% Fe as Fe2O3) at an inlet temperature of ≥175°C (e.g. 190 210 ºC) to form a gas stream 7 in which the CO has been converted to carbon dioxide (CO2, preferential oxidation 6 (PROX)); (d) removing the CO2 9, e.g. by pressure swing absorption (PSA) 8; (e) passing the CO2 depleted stream 10 over a methanation catalyst to form a methanated gas stream, (f) optionally adjusting the hydrogen:nitrogen molar ratio to form an ammonia synthesis gas; and (g) passing the ammonia synthesis gas 12 over a catalyst to form ammonia 14. Some of the removed CO2 may be reacted with formed ammonia to form urea. |
