- 學位論文
生質物供應後勤之成本與碳排放分析
Costs and Carbon Emissions Analysis of Biomass Supply Logistics
摘要
低溫碳化（torrefaction）為一在無氧環境下，通入惰性氣體以燃燒進料之熱處理技術，以此技術處理生質物可以形成緻密的能源載體，使其體積減小易於後續處理與運輸。本研究目標乃探討在生質能後勤當中加入低溫碳化來處理兩種生質物（稻稈與狼尾草），分析其對於生質物供應鏈所造成之影響。 生質能後勤涵蓋收集、前處理、運輸與儲存，以分散/集中式低溫碳化技術結合兩種運輸路線，探討桃園縣境內生質物收集流程產生之成本、能源使用與二氧化碳排放情形。利用地理資訊系統為平台，呈現生質物空間分佈與路網，並且修改文獻提及之參數條件，建立成本試算表作為成本分析工具。 桃園縣整年可提供稻稈75,342公噸，狼尾草59,323公噸。稻稈後勤成本介於2371 ~ 2988元/公噸，主要花費在運輸成本約26 ~ 45%。在發電效率35%下，納入低溫碳化處理會增加稻稈後勤成本，其發一度電產生之利潤反而高於未納入低溫碳化所產生之利潤；狼尾草後勤成本介於1348 ~ 1925元/公噸，運輸成本占42 ~ 72%。納入低溫碳化處理雖然增加後勤成本，而且狼尾草熱值較低並無發電利潤，低溫碳化處裡卻可減少其虧損。 生質物利用之總能源投入與二氧化碳減量評估，如完全利用全年桃園縣產生的生質物，發電效率25%以上即可產生淨能源效益；以兩種生質物替代燃煤使用量，發電效率10%以上即可產生二氧化碳減量，經低溫碳化處理最高可減少0.0376%之全國二氧化碳排放量，未以低溫碳化處理則可減量0.0263%，此結果可以作為未來推廣生質物政策方面參考或判斷之價值。
並列摘要
Torrefaction is a thermal pretreatment technology performed at atmospheric pressure in the absence of oxygen. The process can convert biomass at modest scales into dense energy carriers that ease transportation and handling. The objective of this study is to examine the impact of torrefaction on a two biomass (rice straw and Pennisetum) supply chain logistics. The logistics involves biomass collection, handling, transport, storage, and centralized or distributed torrefaction. We evaluate four alterations to a hypothetical Taoyuan county’s biomass collecting network to discern the conditions under which the changes constitute logistics improvements to cost, energy, and emissions. A spreadsheet tool was developed to analyze the cost of the whole process based on parameters from literature data or local data. The available biomass of rice straw and Pennisetum in Taoyuan county were 75342 and 59323 ton/year, respectively. The results showed that the logistic costs of rice straw were $2371 - 2988 per ton, with roughly 26 - 45% transport costs. At 35% electric generation efficiency, the profit of generating electric power from rice straw with centralized/ distributed torrefaction can be as low as 0.02/ 0.25 $/kWh, in contrast to -0.27/ -0.14 $/kWh without torrefaction. For Pennisetum, the logistic costs were $1348 - 1925 per ton, with roughly 42 - 72% transport costs. Although the consideration of torrefied biomass would increase the total costs, the utilization of that can be in place of coal consumption by 11,900 ton-coal/year, and reduce CO2 emissions up to 0.0376% of the whole country CO2 emissions in Taiwan, in contrast to 0.0263% with non-torrefied biomass.