稻作殘體發電之經濟評估及金觸媒富氫選擇性一氧化碳氧化反應

Economics Evaluation of Electricity Generation from Rice Residues and Study of Gold Catalysts for Selective Oxidation of CO in H2-rich Stream

楊建邦(Chien-Pang Yang)

指導教授 ： 萬本儒

國立臺灣大學/工學院/化學工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00638

摘要

農作物收割後留下的殘體可作為生質能源，生質能源為循環不息的再生能源的一種，利用生物體儲存的化學能，經轉換以獲得電能或熱能，其二氧化碳的淨排放量為零。將稻作殘體用於氣化發電，依發電效率不同，設立10.83-64.98 MW的大型稻草發電系統，並以現有的100 kW小型稻殼發電系統做為規模放大的基準，經濟評估的結果顯示，發電系統要獲得淨利，除發電的收益外，稻灰的價格必須高於4,594元/公噸。2000年台灣產稻殼318,312公噸、稻草1,334,240公噸，若全數用作於發電，可獲得367,233,649度電，佔年發電量的0.22%，且減少二氧化碳排放313,985公噸，佔年排放量的0.14%。

燃料電池以氫氣做為原料，提供一高效率無污染的潔淨能源。藉由選擇性一氧化碳催化氧化的觸媒系統，移除富氫氣體中的一氧化碳，避免毒化燃料電池的電極。模擬富氫氣體成分進行反應的熱力學平衡，在燃料電池的操作溫度，平衡偏向於一氧化碳氧化，且水氣的存在更有助於抑制氫氣氧化。實驗是將四種以相同製備條件載負於不同性質擔體的金觸媒 – Au/Y、Au/γ-Al2O3、Au/AlPO4-5及Au/MgO，在相同條件下進行選擇性一氧化碳氧化反應，Au/γ-Al2O3的一氧化碳轉化率可達90%以上，且穩定性佳；而Au/MgO的選擇率達100%。

關鍵字

生質能 ； 稻作殘體 ； 氫 ； 稻殼 ； 氣化 ； 經濟評估 ； 催化燃燒 ； 發電 ； 燃料電池 ； 一氧化碳氧化 ； 金觸媒

並列摘要

Crop residues after harvest are treated as one kind of biomass. Biomass energy, one of circulating renewable energy resources, is utilized as electricity power or thermal energy converted from chemical energy stored in organism bodies and its net emission of carbon dioxide is zero. Gasification of rice residues generates electricity and remains rice ash as byproduct. The capacity of a rice straw power plant depends on its overall efficiency and is between 10.83 and 64.98 MW. This work scales up and takes economic estimation for building a large-scale rice straw power plant based on an available small-scale 100 kW rice husk power plant. The results reveal that a rice straw power plant has net profit while the cost of rice ash is over 4,594 NTD/ton besides the profit of electricity.

In 2000, all the rice husk and straw with yield of 318,312 and 1,334,240 tons respectively in Taiwan were utilized for power generation. The potential of electricity generation was 367,233,649 kWh, which is 0.22% of total electricity generation. And the potential of reduction of emission of carbon dioxide was 313,985 ton, which is 0.14% of total emission.

Fuel cell fed hydrogen provides clean energy with high efficiency and no pollution. In order to remove carbon monoxide in H2-rich gas stream to prevent electrode from poisoning, we introduces a selective catalytic oxidation system. Simulation of thermodynamic equilibrium in H2-rich gas composition shows that it is preferred for CO oxidation in equilibrium at fuel cell operating temperature and water vapor suppresses H2 oxidation. Selective CO oxidation reactions are carried out with four gold supported catalysts prepared by the same processes, including Au/Y, Au/γ-Al2O3, Au/AlPO4-5 and Au/MgO. Under the same reaction conditions, Au/γ-Al2O3 exhibits high CO conversion of 90% with good stability and Au/MgO exhibits high selectivity of 100%.

並列關鍵字

fuel cell ； CO ； biomass energy ； gold catalyst ； H2 ； economics evaluation ； gasification ； hydrogen ； residue ； catalytic combustion ； monoxide ； rice husk ； power generation

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