| dc.description.abstract | The scientists believe the excessive carbon dioxide cause the global warming now. Therefore, the technology of carbon capture and storage is very important. Pressure swing adsorption (PSA) process is one of the methods to capture carbon dioxide in flue gas. This method uses adsorbents to separate gases with different adsorption selectivities in the mixed gas and is a continuous cycle process. This study aims to capture carbon dioxide in the flue gas of coal-fired power plants, and uses zeolite 13X as the adsorbent to achieve a bottom carbon dioxide product with purity 90% and recovery 90%.
To verify the reliability of simulation program, the results of the breakthrough curve experiment and the 1-bed 3-step PSA process experiment, which is used to capture the flue gas of coal-fired power plant, were compared with the simulation results. Both the experiment and simulation results are consistent, which shows that the simulation program is reliable. Next, the first stage 2-bed 6-step PSA and the second stage 1-bed 3-step PSA are used as the two-stage PSA process to simulate the separation of flue gas (11% CO2, 89% N2) after desulphurization and water removal in coal-fired power plant. The simulation results show a bottom product CO2 purity at 90.33% with 78.82% recovery.
Finally, this study combined the simulation of 2-bed 6-step PSA process with design of experiments (DOE) method to find the optimal operating conditions of the first stage PSA. After simulation analysis, the bottom product CO2 purity 62.17% with 94.75% recovery from the first stage PSA was obtained while at feed pressure 4 atm, vacuum pressure 0.05 atm, cocurrent depressurization 1 atm, bed length 80 cm, step 1/4 time 302 s, step 3/6 time 60 s, feed CO2 concentration 13.76% as the optimal results. After the second stage PSA process, we obtained a bottom product CO2 purity at 90.33% with 90.26% total recovery. The total mechanical energy consumption was estimated to be 1.55 GJ/t-CO2. | en_US |