On the Conversion of Supercritical CO2 to Carbonate

• Main Authors: CHEN WEI-JEN, 陳威仁
• Other Authors: 戴怡德
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/33674597291978505767

碩士 === 國立臺灣大學 === 化學工程學研究所 === 91 === Abstract It is believed that massive CO2 released into atmosphere has a serious consequence on the aggravation of greenhouse effect. In order to solve this problem, we have introduced a safe and permanent CO2 disposal method based on combining CO2 chemically with silicate minerals, which are abundant on earth to form stable carbonate. The process utilized a slurry containing a mineral reactant, such as wollastonite, and the supercritical CO2 in a batch reactor. The CO2 was absorbed into the slurry and then caused the dissolution of the mineral and the precipitation of calcium carbonate. The amount of CO2 fixed in the solid phase was measured by thermogravimetric analysis (TGA). The effects of the variables, including reaction temperature, mineral particle size, operating procedure, and the solution chemistry on the conversion of a mineral were studied. A conversion of 81.6% for wollastonite(53∼66μm) was achieved when the sample was reacted at 80℃ and 1240psig(8.6MPa) for 6h. Moreover, using the procedure of releasing CO2 from the reactor isothermally at the end of reaction can obviously improve the conversion to 94.0%. In addition results were improved when a sodium bicarbonate solution was used instead of distilled water. The test was conducted with wollastonite(38~43μm) in sodium bicarbonate solution(1M) at 1240psig(8.6MPa) for 6h when the temperature was 110 ℃, the conversion was 90.2%, as compared with that in distilled water of 70.5%. Key words: carbonation, carbon dioxide sequestration, CO2 conversion, supercritical CO2, wollastonite