Simulation of Hydrogen Production via Chemical Looping Processes with Coal and Methane Fuels

• Main Authors: Yen-Shao Lu, 盧彥劭
• Other Authors: Hao-Yeh Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/51866664811617682317

碩士 === 國立臺灣科技大學 === 化學工程系 === 104 === In this study, the chemical looping process model setup, simulation and analysis is finished by using the Aspen Plus simulator. The fuel may be changed because of the coal prices or the production rate. In this study, three kinds of coal are demonstrated the fluctuation of fuel sources. The results show that the minimum oxygen carrier rate (Rmin) of Pocahontas No.3, ASC and PRB are 1.21, 1.38, and 1.6 respectily; it is found that the higher moisture of coal should operate at high oxygen carrier circulation rate. Three situations are discussed in this study. By reducing the steam flowrate, the partial oxygen carrier sends to the air reactor to oxidize. The whole system reaches heat balance but the hydrogen yield decreases 32 % to 44 % from the maximum hydrogen yield case. Furthermore, the ash deformation may take place if the air reactor outlet temperature is higher than the ash deformation temperature (ADT). The results show that the ASC and PRB should be operated at 1.19 Rmin and 1.24 Rmin to prevent ash deformation. In the 30 kWth ASC CDCL simulation, the oxygen carrier circulation rate is 4204.5 g/min when the air outlet temperature is 1050 oC. In the adiabatic simulation, the fuel reactor and hydrogen generator outlet temperature is not constant. The system reachs heat balance conidition when the air reactor outlet temperature is the same with fuel reactor inlet temperature; it indicates the oxygen carrier circulation rate and steam inlet would affect the air outlet temperature. At the maximum oxygen carrier circulation rate: The minimum air flowrate is only regenerated the oxygen carrier to Fe2O3, it may not reach the transport request. By increasing the air flowrate to reach the gas delivery, the amount of air will take away more heat, so the hydrogen yield is lower than the minimum air flowrate. If the oxygen carrier is operated at lower circulation rate, the fuel reactor outlet temperature would decrease. It can be adjusted by the oxygen carrier circulation rate to achieve the more reasonable operating temperature of fuel reactor.