Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 33.4.5 N 2 O decomposition by extension of the reactor chamberDescriptionYara has developed and patented a technology that reduces the production of N 2 O by increasingthe residence time in the reactor at high temperatures (850 – 950 °C). This technology consistsof an ‘empty’ reaction chamber of approximately 3.5 m extra in length between the platinumcatalyst and the first heat exchanger. For illustration, see Figure 3.7. Due to the longer residencetime of 1 – 3 seconds, a N 2 O reduction of 70 – 85 % might be obtained, since N 2 O is metastableat higher temperatures and decomposes to N 2 and O 2 .NH 3airPlatinum gauze packExtended reactor chamberHeatrecoveryTo absorberFigure 3.7: Decomposition of N 2 O by extension of the reactor chamberFigure based on [87, infoMil, 2001]Achieved environmental benefitsThe example plant achieves an N 2 O emission level of 2 – 3 kg/tonne 100 % HNO 3 [80, Jenssen,2004, 104, Schöffel, 2001] or about 400 ppm [17, 2nd TWG meeting, 2004].Cross-media effectsNone believed likely.Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers 121