| 摘要: | 本研究以生命週期評估(Life Cycle Assessment, LCA)方法探討生物可分解塑膠-聚乳酸(Polylactic acid, PLA)在台灣的應用與綠色創新，並探討PLA與傳統塑膠之環境效益比較，分別從能源耗用、溫室氣體排放及其他重要環境議題探討之。研究結果主要包含三個部份：第一部份：聚乳酸在台灣之生命週期評估，進一步與傳統塑膠比較LCA；第二部份：PLA之生命週期末端處理方式，並分別以焚化、掩埋與堆肥三種處理方式，探討溫室氣體排放量之差異；第三部份：以綠色設計之萃智創新理論，進行個案綠色設計與改良，並以生命週期評估為綠色設計之環境績效指標。其主要結果如下：
1. 對於聚乳酸之生命週期評估結果，其能源總投入為48.01 MJ，以原料階段最大占整體生命週期的87.84%，其次為運輸階段及製造階段；在溫室氣體排放方面，其總溫室氣體排放為1.41 kgCO2-eq./kg，其中焚化階段之排放量最大為1.94 kgCO2-eq./kg，其次為運輸階段及製造階段。
2. 聚乳酸應用在食品包裝之生命週期評估，其溫室氣體排放為26.13 kgCO2-eq.，比傳統塑膠PET（101.27 kgCO2-eq.）、 PP（71.93 kgCO2-eq.）及 PS（102.43 kgCO2-eq.）較低；在能源耗用上， PLA之能源投入為889.38 MJ，仍低於傳統塑膠。
3. 聚乳酸之溫室氣體排放推估，以IPCC推估方法進行推估PLA之焚化、掩埋、堆肥之處理方式，以掩埋處理所排放的溫室氣體為最多為8.212 kgCO2-eq./kg，其次為堆肥處理為2.056 kgCO2-eq./kg及焚化處理的1.848 kgCO2-eq./kg。
4. 以台灣地理系統，並以焚化處理為末端處理，則PLA之溫室氣體排放為2.159 kgCO2-eq./kg。
5. 以生命週期評估為評估指標，綠色設計個案，新式包裝比便利袋，能夠節省24%的能源投入並降低42%之溫室氣體排放。
In this study, the environmental benefits of Polylactic acid (PLA) investigated for the case study and green innovation by life cycle assessment (LCA) in Taiwan. Moreover, PLA compared to the traditional plastics from the viewpoint of energy consumption, greenhouse gases and other important environmental issues. The results indicated three parts: Part one concerns with PLA life cycle assessment and the comparisons among the traditional plastics; the second part is the greenhouse gases estimation of PLA for the treatments with incineration, landfill and composting; Part three is a case with green design method for the improvement using LCA indicator. The main results are as follows:
1. PLA life cycle assessment results, the energy input is 87.84% at raw materials stage with the value at 48.01 MJ, followed by the transport stage and the manufacturing stage; The greenhouse gases are 1.94 kgCO2-eq./kg at incineration stage, and with 1.41 kgCO2-eq./kg for the full life cycle.
2. For the food packing case, PLA greenhouse gases is 26.13 kgCO2-eq., and the traditional plastics are PET (at 101.27 kgCO2-eq.), PP (at 71.93 kgCO2-eq.) and PS ( at 102.43 kgCO2-eq.), respectively. Moreover, PLA energy inputs are low than traditional plastics with the value of 889.38 MJ for full life cycle.
3. The greenhouse gases estimated the emissions for incineration, landfill and composting for the PLA case by IPCC methods. The higher value is landfill with 8.212 kgCO2-eq./kg, followed by composting and incineration with the value at 2.056 kgCO2-eq./kg and 1.848 kgCO2-eq./kg, respectively.
4. The waste treatment scenarios of Taiwan for PLA case study, the greenhouse gases emission are 2.159 kgCO2-eq./kg.
5. The green design cases evaluated the environment impact by LCA, the new packaging bags can save the energy with 24% and lower greenhouse gases emission with 42% than transitional bags. |
