| dc.description.abstract | With the industrial revolution came the burning of large amounts of fossil fuels, resulting in the release of carbon dioxide and intensifying the greenhouse effect, leading to climate change. In recent years, there has been an increased awareness of environmental protection, and the issue of reducing carbon dioxide has received close attention. One method for achieving this is Pressure Swing Adsorption (PSA), which utilizes the different adsorption properties of gases to separate mixed gases. It is a physically-based adsorption method that requires low investment costs and simple operation. In this experiment, PSA method was used to capture carbon dioxide from the flue gas emitted by coal-fired power plants.
First, the high-pressure gas analyzer and digital recording balance were used to measure the isothermal adsorption curves of COSMO 13X for CO2 at different temperatures. The equilibrium adsorption capacity at different temperatures and pressures was calculated to confirm that the chosen adsorbent in this experiment exhibits good separation efficiency for carbon dioxide.
Next, a two-stage vacuum pressure swing adsorption (VPSA) process was employed, with COSMO 13X chosen as the tower packing material, to separate N2 and CO2 in the flue gas emitted by the Taichung coal-fired power plant. Firstly, the first stage experiment (two-bed six-step PSA) was conducted to achieve a high carbon dioxide recovery rate. Then, through the second stage experiment (single-bed three-step PSA), the purity of carbon dioxide was increased. To investigate the influential factors in the results of the first stage experiment, a combination of experimental design and analysis was employed, using a two-level three-factor full factorial experimental design. These three factors are the time for steps 1/4, the time for steps 3/6, and the co-current depressurization pressure. By studying the effects of these factors on purity, recovery rate, and energy consumption in the experimental results, regression models were established for each response to determine the optimal operating conditions. The objective is to achieve an 80% or higher carbon dioxide recovery rate in the first stage experiment.
After comparing four different optimizations, it was determined that when the time for step 1/4 is 250 seconds, the time for step 3/6 is 40 seconds, and the Co-current depressurization pressure is 0.85 bar, the optimal result yields a carbon dioxide purity 79.11 % with recovery 87.08% in the first-stage. | en_US |