| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系博碩士班 === 101 === In recent years, due to high energy demands, many researchers focus on developments of CO2 capture and separation in order to reduce CO2 emissions. Among all stationary emission sources, coal-fired power plants were one of the largest sources of CO2 emission. A preliminary analysis from US DOE indicated that an economically feasible approach for CO2 from a stationary source should further cost-down to less than US $30. Therefore, the main purpose of this study was to develop a cost-effective and stable sorbent to capture CO2 from coal-fired power plants.
Conventionally, majority of the commerical CO2 capture processes bases on chemical absorption solvents, such as monoethanolamine (MEA) and diethanolamine (DEA). However, above-mentioned liquid amine-based processes suffer from high energy consumption, solvent deterioration, and equipment corrosion problems, etc. Thus, ionic liquids which possess better thermal stability and chemical stability were used to absorb carbon dioxide in this study. It was observed that the sorption capacity was too low due to its high viscosity. Furthermore, we incorporated the ionic liquid onto the mesoporous silica (MSF) to capture CO2, which also found to have low CO2 sorption capacity below the criteria.
Moreover, a variety of methods was deveope to improve the stability and sorption performance of the adsorbents. Different stabilizers such as amino acid ionic liquids (3-Aminopropyl) tributylphonium 1-a-diaminocaproic acid salt ([aP4443][Lys]), titanium isopropoxide (TIP) and poly(ethylenimine) (branch) (PEI) were added with TEPA and then incorporate into MSF to form the sorbent composites. A variety of different spectroscopic and analytical techniques, such as small angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FT-IR), elemntal analysis (EA), Brunauer-Emmet-Teller analysis (BET), thermo gravimetric analyzer (TG/DTG) were used to characterizethe physicochemical properties of various materials. The CO2 sorption performance was also carried out under different simulated conditions (temperature and humidity). Also, CO2 sorption under low CO2 concentration (400 ppm) was performed in order to evaluate the possibility of CO2 capture form ambient atomosphere. The mechanisms of CO2 sorption in particular for the structural changes of amine were discussed in this study.
Different preparation methods were used to obtain stable amino-modified adsorbents. Results obtained from this study revealed that pure ionic liquid modified and TIP-modified adsorbents possessed superior performance for the single cycle and multiple cycles adsorption-desorption process. In addition, the results of EA showed that CO2 adsorption efficiency may be related to the high N contents, the existence of moisture and CO2 concentration.
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