| 摘要: | 本研究利用固定床熱裂解反應系統，探討聚碳酸酯(Polycarbonate, PC)及熱塑性聚氨酯(Thermoplastic polyurethane, TPU)共同熱裂解轉換為能源之可行性及其產物分佈特性。實驗條件除控制溫度介於550~650 ℃外，並以650 ℃溫度條件下，分別控制摻混比1:3、1:1 與3:1。研究同時利用熱重分析技術，進一步分析試驗材料之熱反應動力參數，及評估不同試驗材料之協同效應。
根據熱重分析之結果顯示，PC 及TPU 之反應活化能分別為402.42 kJ/mol 及125.23 kJ/mol，當PC 與TPU 摻混進行共裂解反應時，PC 之反應活化能隨TPU添加而有降低之現象，其中PC 與TPU 以1:1 為混合條件，其反應活化能約為124.92 kJ/mol，亦即PC 與TPU 摻混後，逐漸趨向於TPU 之熱反應特性。此外，根據摻混後PC 與TPU 之質量損失變化率可知，當PC:TPU=1:1 時，熱分解反應過程產生協同效應，因此，反應活化能亦隨著摻混兩種試驗材料後，呈現降低之趨勢。
裂解反應溫度對PC 及TPU 裂解之產物分佈影響並不顯著，其中裂解溫度控制在650 ℃時，主要之共裂解產物為氣相產物，約占68%至80%之間，其中以PC與TPU 摻混比1:1 條件為例，其產物分佈特性分別為68.8%之氣相、24.4%之液相及6.8%之固相產物。進一步分析液相產物之種類與特性，前述24.4%之液相產物中，主要為23.54%之重質油及0.87%之輕質油。另以液相產物之氧/碳莫耳比(O/C 比)進行油品老化發生潛勢之評估，結果顯示PC 與TPU 以1:1 摻混進行共同裂解，輕質油產物之氧/碳莫耳比，可降低至0.07，亦即共同裂解可有效降低輕質油品之老化現象發生潛勢。液相產物之物種分析結果顯示，PC 及TPU 裂解產生之重質油，隨裂解溫度550 ℃增加至650 ℃時，主要物種由芳香族化合物轉換為含氧化合物；而輕質油之物種，則均以含氧化合物為主。當進行PC 與TPU 共同裂解反應時，不論摻混比例之改變，重質油之含氧化合物產率明顯增加，而輕質油中芳香族化合物產率，亦呈現增加之趨勢。
根據能源密度分析結果顯示，PC 及TPU 裂解產物之能源分布特性，主要為氣相產物，且總能量密度隨裂解溫度增加而增加。以裂解溫度650℃為例，PC 及TPU 裂解產物之總能源密度分別為0.30 及1.37，亦即TPU 之熱裂解轉換能源之利用效率較佳。當共同裂解反應條件為1:1 時，其總能源密度約為0.86，亦能有效達到能源轉換應用之目的。整體而言，本研究成果已初步建立PC 及TPU 共同裂解之熱反應動力、產物分佈及物種特性，同時亦評估裂解產物之總能源密度，未來若能進一步放大規模試驗，並分析裂解產物特性及其能源效益，將有助於後續推動PC 與TPU 共同裂解技術之發展與應用。;This research aims to evaluate the energy conversion efficiency and pyrolytic products partitioning characteristics in co-pyrolysis of Polycarbonate (PC) and
Thermoplastic polyurethane (TPU) using a fixed-bed reactor with controlling the temperature at 550-650℃ and blending ratio of 1:3, 1:1, and 3:1 at 650℃. The thermogravimetric analysis technology was also used to analyze the tested materials’ thermal reaction kinetic parameters and evaluate the synergistic effect between the tested materials.
According to the thermogravimetric analysis results, the reaction activation energies of PC and TPU were 402.42 kJ/mol and 125.23 kJ/mol, respectively. The reaction activation energy of PC decreased with the TPU blending ratio increasing in co-pyrolysis. In the case of PC:TPU=1:1, the reaction activation energy was approximately 124.92 kJ/mol. It implied that the thermal reaction characteristics of coblending of PC and TPU have tended to TPU thermal reaction characteristics. In addition, according to the results of mass loss rate in co-pyrolysis of PC and TPU, the
synergistic effect occurred during the thermal decomposition reaction process as coblending of 50% PC and 50% TPU. Therefore, the reaction activation energy showed a
decreasing trend with the co-blending of the tested materials.
The pyrolysis temperature does not significantly affect the partitioning of PC and TPU pyrolytic products. When pyrolysis temperature is controlled at 650 °C, the gasphase
pyrolytic product was the majority and ranged between 68% and 80%. In the case of co-blending 50% PC and 50% TPU, the pyrolytic product partitioning percentage was approximately 68.8% of the gas phase, 24.4% of the liquid phase, and 6.8% of the solid phase, respectively. Meanwhile, 24.4% of the liquid-phase product consisted of 23.54% of the heavy fraction oil and 0.87% of the light fraction oil. According to the Oxygen-to-Carbon molar ratio (O/C ratio) in the liquid-phase product, the O/C ratio of the light-fraction oil could decrease to 0.07 during the co-pyrolysis of the PC and TPU process. It implied that the pyrolytic oil aging could be migrated by co-blending PC and TPU. The heavy fraction oil speciation derived from PC and TPU was aromatics compounds by pyrolysis. However, the oxygenated hydrocarbon compounds became dominant as the pyrolysis temperature increased from 550℃ to 650℃. The dominant
speciation of the light fraction oil was oxygenated hydrocarbon compounds pyrolyzed between the temperature of 550℃ and 650℃. In the case of the co-pyrolysis of PC and
TPU with different blending ratios, the yields of oxygenated hydrocarbon compounds in the heavy fraction oil and aromatics compounds in the light fraction oil both increased
significantly.
Based on the energy density analysis results, the gas-phase pyrolytic product mainly contributed to the energy production in the co-pyrolysis of PC and TPU. The total energy density of all pyrolytic products increases with the pyrolysis temperature increasing. In the case of pyrolysis temperature of 650 ℃, the total energy density of pyrolytic
products in pyrolysis of PC and TPU were 0.30 and 1.37, respectively. It implied that TPU could provide a good energy conversion efficiency. Besides, in the case of 50%
PC and 50% TPU blending conditions, the total energy density of all pyrolytic products was approximately 0.86. It also could effectively achieve the energy conversion application. In summary, the results of this research have preliminarily
established the thermal reaction kinetics, pyrolytic product partitioning, and speciation in co-pyrolysis of PC and TPU. The total energy density of the pyrolytic products was
also successfully evaluated. To further successfully perform the scale-up test and assess the pyrolytic product characteristics and their energy benefits in the future, it will help promote the development and application of the co-pyrolysis technology of PC and TPU. |
