二氧化碳與光源對小球藻油脂累積之影響暨生命週期評估其效益

The effects of carbon dioxide and light on lipid productivity of chlorella and life cycle assessment

施裕淳(Yu-Chun Shih)

指導教授 ： 黃郁慈

中原大學/工學院/生物環境工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600788

摘要

能源一直是這個世界最重要的議題之一，隨著工業以及科技的與日俱進，能源的需求更是日益增大，但是世界的石化相關能源卻逐漸枯竭，尋找替代能源就變成這個時代急迫的課題。透過光合作用，藻類吸收固定空氣中二氧化碳生長增加其生物質，最後產生生質能源，因此，如果製造成本能再降低，生物能源就是一種綠色的能量源。
本研究討論了SA與PA兩種藻種於T5日光燈與LED燈板並通入空氣、10%二氧化碳、20%二氧化碳下的生物質累積、生物質產率、油脂含量、油脂產率與單位油脂碳排放量，分析在不同生長環境下的油脂累積率能幫助我們了解其最佳的油脂累積狀態，進而提高其油脂的產率，藉由分析小球藻的生命週期，來了解養殖小球藻與萃取油脂時所消耗的能量與排放的碳量，同時以小球藻作為生質能源原料對於生態環境是否造成其他的衝擊與問題，也是本研究的範疇。
我們得到以下結果：(一) SA須於T5日光燈管為光源並通入10%二氧化碳培養，會得到生物質產量、生物質產率、油脂產率與油脂含量為1300±1 mg/L、0.186±0 g/L-1/d-1、80.15±0.2 mg/L-1/d-1、560.3±1.7 mg，PA則須於LED燈板為光源並通入10%二氧化碳培養，會得到生物質產量、生物質產率、油脂產率與油脂含量為1335±7 mg/L、0.191±7 g/L-1/d-1、64.46±0.3 mg/L-1/d-1、451.23±6.4 mg。(二)如需獲得較高的油脂含量百分比，SA須於T5日光燈管為光源通入空氣下培養
，會達43.3±0.2%，PA須於T5日光燈管為光源通入20%二氧化碳下培養，會達49.5±1.2%。(三)在油脂的產率與產量方面SA表現的較佳，在生物質的產率與累積方面則是PA有較好的表現。(四) 在生命週期評估方面，以生產一單位(毫克)的藻油為目標後，最低的碳排放量值都是出現在以LED燈板光源並通入10%二氧化碳培養時，分別是SA藻種的0.7316 kg碳排放量以及PA藻種的0.7351 kg碳排放，以LED燈板作為光源培養所生產的藻油可以比以T5日光燈管作為光源培養所生產的藻油省下41%的碳排放。

關鍵字

微藻 ； 二氧化碳 ； 生質能源 ； 生命週期評估

並列摘要

Energy has been one of the most important issues in the world. With the progress of industry and technology, energy demand is increasing. Because the world's petrochemical related energy has gradually dried up, finding alternative energy has become an urgent challenge. The stocks of bioenergy are from biomass, and carbon dioxide (CO2) can be fixed during the growth of biomass through photosynthesis. Therefore, bioenergy can be a green energy source if the cost of manufacture can be
decreased.
This study discusses the biomass accumulation and productivity, oil content and productivity, and carbon emissions rate per units of lipid amount of two algae strains, SA and PA, under the cultivation parameters of T5 fluorescent lamp, LED light board, and aerated with air, 10% CO2 or 20% CO2. Analysis of lipid accumulation rate under different growth conditions can help to understand the optimal lipid accumulation condition and thereby increasing the lipid productivity. Furthermore, how to minimize the energy cost for producing bioenergy and maximize the productivity has become a major issue in the area of energy-saving with lower carbon impact. By analyzing the life cycle of chlorella, we can understand the energy consumption and carbon emissions during cultivation and extraction of oil consumed. In addition, whether using chlorella as a raw material for bioenergy will cause other ecological
impact or not is also the scope of this study.
We got the following results:(1) SA cultured at T5 fluorescent lamp with 10% CO2 could obtain higher biomass accumulation and productivity, lipid productivity and content of 1300±1 mg/L, 0.186±0 g/L-1/d-1, 80.15±0.2 mg/L-1/d-1, and 560.3±1.7 mg, respectively. PA cultured at LED light with 10% CO2 culture could obtain higher biomass accumulation and productivity, lipid productivity and content of 1335±7 mg/L, 0.191±7 g/L-1/d-1, 64.46±0.3 mg/L-1/d-1, and 451.23±6.4 mg, respectively. (2) SA cultured at T5 fluorescent lamp with air could obtain higher lipid ratio of 43.3±0.2%, while PA cultured at T5 fluorescent lamp with 20% CO2 obtained ratio of 49.5±1.2%. (3) SA can resulted in better lipid productivity and content, while PA can resulted in better biomass productivity and amount. (4) When we set up the goal as producing one unit (mg) of lipid in the life cycle assessment, the lowest values of carbon emission were both under the cultivation parameters of LED light and 10% CO2 for SA (0.7316 kg carbon), and PA (0.7351 kg carbon), respectively. Using LED than T5 as light source can save up to 41% of carbon emissions to produce algal lipid in this study.

並列關鍵字

algae ； CO2 ； biomass energy ； LCA

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