2017 Volume 57 Issue 3 Pages 435-442
Hydrogen sulfide (H2S) removal and catalytic ammonia (NH3) decomposition performance of limonite in the presence of coke oven gas (COG) components has been studied in a cylindrical quartz reactor at 300–850°C under a high space velocity of 51000 h−1 to develop a novel hot gas cleanup method. The H2S removal behavior in 50% H2/He depends on the temperature, with high performance observed at lower temperature. An investigation of the removal behavior of H2S in the presence of COG components (CH4, CO, CO2 and H2O) at 400°C reveals that CH4 does not affect the removal performance. On the other hand, the coexistence of CO drastically decreases the H2S removal performance. However, the addition of 5% H2O to 50% H2/30% CH4/5% CO/He dramatically improves the H2S removal performance, whereas the performance is low at 5% CO2 with 50% H2/30% CH4/5% CO/He. In addition, the H2S breakthrough curve strongly depends on the space velocity.
The limonite catalyst achieves almost complete decomposition of NH3 in He at 850°C until 240 min. When the decomposition run is performed in the presence of COG components, the coexistence of 30% CH4 deactivates limonite with significant formation of deposited carbon. On the other hand, the addition of 5% CO2, 5% H2O or 5% CO2/5% H2O to 50% H2/30% CH4/5% CO improves the catalytic activity without carbon deposition, and >99% conversion of NH3 to N2 is maintained until 240 min.