以CaO捕獲廢氣中二氧化碳溫室氣體之吸附與再生效能研究

Abstract

本研究之主要目標是以台灣3個不同礦區所生產的石灰石進行CO2溫室氣體吸脫附特性研究。探討之參數包括幾個重要操作參數對CO2吸脫附之影響，本次測試之操作參數包括石灰石(CaCO3)的種類、石灰(CaO)補充率、再生循環次數、CO2體積分率、處理氣體含水率等。 測試結果顯示，實驗所用的各種類石灰石經過鍛燒產生之CaO，對CO2吸附量相差很小。當石灰石在700℃恆溫進行CO2的吸脫附實驗時，有較高的吸附量與較佳的反覆吸脫附再生性，但是其吸脫附速率較低；而在950℃脫附、650℃吸附時，則有較高的吸脫附速率，但其CO2吸附量較低。在石灰(CaO)補充率實驗中，隨著補充率增加，CO2吸附量亦隨之提高，唯增加幅度不大。而於吸附時通入水氣增濕，對於CO2的吸附有加強的效果。最後隨著CO2體積分率的升高(10%增加至50% v/v)，CaO對CO2的吸附速率顯著提高，但吸附量會有略微下降的趨勢。而反覆10次的吸脫附實驗雖然CO2吸附量逐漸降低但還是維持0.2 gCO2/gCaO吸附量，而且衰減的速率的有越來越慢的趨勢。 經由此次研究後，可知CaO的確具有相當高的CO2吸附量，但商用石灰石有再生率不佳的缺點，如何提升再生率，將是未來研究的課題。

The purpose of this study is to understand the CO2 adsorption characteristics and its regeneration by limestone from three different mining areas in Taiwan. The important operating parameters being researched are limestone type, limestone supplement volume, number of regeneration times, different CO2 concentration, and gas moisture content. The test result indicates that after calcination the difference between each limestone is very small in terms of their CO2 adsorbing amounts. As the adsorption and regeneration of CO2 was at constant temperature of 700℃, it has greater CO2 absorbing amount and regenerative ability, but its adsorption rate is lower. On the other hand, as regenerated at 950℃ and adsorbed at 650℃, the adsorption rate is faster whereas the adsorption amount is lower. In the experiment of limestone supplement volume, as the CO2 supplement rate increases the adsorption capacity is enhanced. The presence of moisture increases the adsorption capacity of CO2. Increasing the CO2 inlet concentration from 10% to 50% (v/v) leads to an increase of the CO2 adsorption rate, but the adsorption capacity is slightly smaller. Result on the 10 times of cyclic adsorption test shows that the CO2 adsorption capacity reduces gradually, but it still maintains at adsorptive capacity of around 0.2g CO2/gCaO.