|摘要: ||本論文主要進行兩階段的甘油製造汽油之化工程序合成與設計，以汽油年產量9萬公噸為目標。由於甘油為生產生質柴油之副產物，預計未來會有大量的甘油可資利用，吾人以每年18萬公噸之甘油為原物料，經過水蒸汽重組法產製合成氣，所得之合成氣再進入甲醇合成反應器產製甲醇，最後再藉甲醇純化塔可得每年11萬公噸99.9 mol% 之高純度甲醇。此高純度甲醇進入甲醇變汽油 (MtG) 之程序反應器，藉反應流出物各成分沸點的差異進行蒸餾分離，遂得每年9萬公噸的C5+ 汽油。本論文之甘油水蒸汽重組反應器與甲醇合成反應器係利用化工熱力學原理進行分析，蒸餾塔則利用吾人提出的「蒸餾塔設計三步驟」作節能設計，如此可以有效地降低再沸器之熱負荷達到節能減碳之效果。論文中特別提到天然氣、熔鹽及冷凍劑等公用設施使用量的計算，利用Aspen Plus 當中的 “Design Spec/Vary” 找出其使用量。|
吾人發現由1 kg的甘油可得2.8 kg的合成氣、再由合成氣得0.6 kg的甲醇，最後可得0.52 kg的C5+。此兩階段的甘油變汽油之程序合成與設計，總設備成本之回收年限約0.72年，化石能源比為5.1，庶幾可稱之為再生能源。
本論文主要應用 “Aspen Plus” 與 “CAPCOST” 兩個軟體，前者用於程序合成與設計，後者則用於工程經濟之分析。本製程研究係結合了程序設計之「洋蔥模式」、經驗法則、換熱器熱能整合以及Aspen Plus嘗試錯誤所得之結果。
In this thesis, we have presented a two-stage chemical process synthesis and design for the production of gasoline from glycerin. The study aims to simulate a plant capacity of 90,000 metric tons per year of gasoline. Because glycerin is the co-product from the biodiesel production, we predict that a large quantity of glycerin we can make good use in the future. Starting with 180,000 metric tons per year of glycerin as the raw material, syngas can be produced through the steam reforming process. Then, syngas in turn is converted into the methanol. And by employing purification process, we are able to obtain the methanol production with 99.9 mol% purity. Ultimately, the high-purity methanol is sent to the MtG (methanol to gasoline) reactor and the effluents from the reactor are eventually separated into the desired products by the nature of their different boiling points. Thus, we can achieve the design goal of 90,000 metric tons per year of C5+ gasoline. It should be emphasized that, in this thesis, the glycerin steam reforming reactor and the methanol reactor have both been analyzed via the principle of the chemical engineering thermodynamics. In regard to the distillation columns, we use a “three-step design procedure” to minimize the reboiler’s heat duty and expeditiously save the energy. We specially mention how to use Aspen Plus with “Design Spec/Vary” function to calculate the quantities of natural gas, molten salt and refrigerant used in the process.
Consequently, we found that 1 kg of glycerin makes 2.8 kg of syngas, 0.6 kg of methanol and 0.52 kg C5+ gasoline. As seen from the engineering economic analysis, we found that we need 0.72 year to recovering the fixed capital cost of manufacture. Since fossil energy ratio (FER) we found is 5.1, this two-stage process from glycerin to gasoline can be regarded as a renewable-energy process.
Two kinds of software are utilized in the research—Aspen Plus and CAPCOST. The former is applied to implement the process synthesis and design; the latter is applied to carry out the economic analysis of the project. In sum, we have integrated the theory of the so-called “onion model”, design heuristics, energy integration of heat exchangers and Aspen Plus’ trial-and-error to accomplish the final process results.