廢棄牡蠣殼資源化用以製備二氧化碳吸附劑

Preparation of CO2 adsorption sorbent by reutilizing waste oyster shell

黃俊強(Jun-Qiang Huang)

指導教授 ： 王竹方

國立清華大學/原子科學院/生醫工程與環境科學系/碩士(2014年)

摘要

本篇研究中將廢棄牡蠣殼與不同的摻雜物進行混合鍛燒用以製備二氧化碳吸附劑，廢棄牡蠣殼資源化的目的不僅可將吸附劑用以降低溫室效應的影響外，同時也可以解決隨意丟棄廢棄牡蠣殼造成的環境問題。第一個實驗先以poly(methyl methacrylate) (PMMA)與廢棄牡蠣殼於高溫爐中以750℃處理下可合成出多孔性三維序列結構(three-dimentional ordered macraporous 3-DOM)，該結構具有高比表面以及大孔洞容量等特性在10 個吸附/脫附 的循環中可以有效提高二氧化碳吸附能力( pm70 ~ 0.19 g CO2/ g sorbent)，相比之下未摻雜PMMA的吸附劑僅有約0.07 g CO2/ g sorbent ；從第二個實驗目的於解決吸附劑在連續的高溫環境下的燒結現象所帶來的影響，探討摻雜耐高溫之ZrO2於廢棄牡蠣殼中並且以兩種不同的熱處理方式進行探討，在高溫電漿處理下可使CaZrO3更為均勻的分布，使抗燒結能力增加，以y=exp(-kt)進行計算後發現K值會隨著ZrO2添加量提高而降低，因此可以得知添加ZrO2後進行熱處理之樣品在多次的吸附/脫附循環中可以更為有效降低二氧化碳吸附能力衰減的速度。後續利用生命週期評估(LCA)方法對兩個實驗中以"搖籃到墳墓"的概念進行環境影響評估，從PMMA摻雜廢棄牡蠣殼的評估中可得知當二氧化碳吸附能力大於20% 時的對於環境的衝擊將會呈現正值；而從第二個實驗中評估結果發現高溫電漿的處理過程中能源耗損較大，所導致的環境衝擊指數也會成正比上升(~5.55 mPt)，因此兩種不同熱處理方式評估下，利用高溫爐熱處理方式(~ 1.25 mPt)對於環境是較高溫電漿合成來的友善。

關鍵字

廢棄牡蠣殼資源化 ； 多孔性三維序列結構 ； 高溫電漿 ； 燒結 ； 生命週期評估

並列摘要

In this study, we demonstrate a means of simultaneously solving two serious environmental issues by reutilization of pulverized waste oyster shells to prepare CaO-based sorbents for CO2 capture. First, waste oyster shell are calcined with poly(methyl methacrylate) (PMMA) nanospheres. Here, a highly surface area and pore volume “three-dimensionally ordered macroporous (3DOM)” structures are formed. After 10 cycles of isothermal carbonation/calcination at 750 °C, the greatest CO2 uptake (0.19 g CO2/g sorbent) is that for the sorbent featuring 70 wt% of PMMA, which is almost three times higher than that (0.07 g CO2/g sorbent) of untreated waste oyster shell. Subsequent experiment is proposed to solve the “sintering effect” during carbonation/regeneration cycles.
By fitting experiment results with an exponential decay equation y=exp-kt, it is found as-determined decay constant (k value) decreases with increasing amount of ZrO2 introduced. This suggests that surface CaZrO3 layer enhances the thermal stability against sintering effect. Following life cycle assessment, whose all input values are collected from our experimental results, suggested that the (a) CO2 uptake efficiency must be greater than 20% or sorbents prepared from limestone mining would eventually produce a net positive CO2 emission in first experiment (b) comparison of materials and energy requirements of mineralizing 1 kg CO2 of plasma and oven thermal treatment, a fewer environmental impacts was calculated of oven thermal treatment.

並列關鍵字

Waste oyster shell ； 3DOM structure ； plasma ； sintering effect ； CaZrO3 ； life cycle assessment

參考文獻

[1] K. Michael, A. Golab, V. Shulakova, J. Ennis-King, G. Allinson, S. Sharma, et al., "Geological storage of CO2 in saline aquifers—A review of the experience from existing storage operations," International Journal of Greenhouse Gas Control, vol. 4, pp. 659-667, 2010.

[2] P. Chiquet, J.-L. Daridon, D. Broseta, and S. Thibeau, "CO2/water interfacial tensions under pressure and temperature conditions of CO2 geological storage," Energy Conversion and Management, vol. 48, pp. 736-744, 2006.

[3] A. Frster, B. Norden, K. Zinck-Jrgensen, P. Frykman, J. Kulenkampff, E. Spangenberg, et al., "Baseline characterization of the CO2SINK geological storage site at Ketzin, Germany," Environmental Geosciences, vol. 13, pp. 145-161, 2006.

[4] J. Gale, "Geological storage of CO 2: What do we know, where are the gaps and what more needs to be done?," Energy, vol. 29, pp. 1329-1338, 2004.

[5] M. Broda and C. R. Müller, "Synthesis of Highly Efficient, Ca‐Based, Al2O3‐Stabilized, Carbon Gel‐Templated CO2 Sorbents," Advanced Materials, vol. 24, pp. 3059-3064, 2012.