Integration of Ammonia Synthesis Gas Production and N₂O Decomposition into a Membrane Reactor

Abstract

H 2 /N 2 synthesis gas is of great importance for the ammonia industry, and its production process is both complex and energy consuming. Nitrous oxide (N 2 O) is a potent greenhouse gas (GHG) that also depletes the stratospheric ozone. Here, we propose a novel concept of a membrane reactor in which ammonia synthesis gas production, N 2 O decomposition, and water splitting are combined. In this process, oxygen produced from N 2 O decomposition and water splitting is removed by a dense oxygen permeable membrane, which then reacts with oxygen-consuming gas. This promising membrane reactor process has been successfully demonstrated by experiment. By optimizing the N 2 O and H 2 O flow rate, a complete N 2 O decomposition is achieved, and a synthesis gas with a molar ratio of H 2 /N 2 = 3:1 is produced at the same time. At 850 °C, a H 2 production rate of 14.85 mL/min and a N 2 production rate of 5.07 mL/min are derived from the membrane reactor with 100% N 2 O conversion and 29.60% H 2 O conversion. The reactor also exhibits excellent stability over a 300 h long-term test. This study will give some constructive guides to the subsequent work on process intensification through the membrane reactor and may lead to the development of green chemical production.