乾濕兩式生質酒精重組程序之製程研究

Dry and Wet Reforming of Bioethanol:a Process Research

簡振宇(Chen-Yu Chien)

指導教授 ： 陳錫仁

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2015年)

https://doi.org/10.6846/TKU.2015.00742

摘要

由於全球對於生質能源越來越重視，生質酒精的產量遂急遽的上升，產量過剩的生質酒精勢必需要找到其它出路；由於生質酒精含氫量高，特別適於當作產氫的原料。本研究主要分別以乾式重組法與蒸汽 (濕式) 重組法兩種方法進行生質酒精重組程序之製程設計，並分別探討其在燃料化學品的合成與燃料電池上的應用。
乾濕兩式重組反應器經過程序軟體Aspen Plus的敏感度分析後，吾人採用之操作條件分別為：(1)乾式：溫度960oC、壓力8 bar、進料比CO2:C2H5OH=1.3:1；(2)濕式：溫度700oC、壓力1 bar、進料比H2O:C2H5OH=6:1。在乾式重組法之應用上，以二甲醚 (DME) 年產量為兩萬七千公噸、純度達99.9 mol%為設計目標，乾式法以生質酒精及二氧化碳為進料，經過重組反應產生合成氣，所得之合成氣再進行單階段程序直接合成燃料化學品二甲醚，在分離程序純化二甲醚之蒸餾塔設計中則利用吾人提出的「蒸餾塔設計三步驟」做節能設計；此外，並針對二甲醚全廠製程進行熱能整合，以求有效達到節能省碳之目的。在濕式重組法之應用上，以生質酒精及低壓蒸汽為進料，經過重組反應產生合成氣，所得之合成氣分別考慮兩種不同的燃料電池應用：(1)一部分合成氣進行變壓吸附純化，得到的高濃度氫氣送入加氫站儲存提供質子交換膜燃料電池 (PEMFC) 車輛之使用，吾人發現氫氣量5.6 kg時PEMFC的輸出功率可達113.2 kW；(2)另一部分含高氫氣組成之合成氣則提供固態氧化物燃料電池 (SOFC) 之固定式區域供電使用，吾人發現氫氣量為285 kmol/h時SOFC可提供之區域供電達4.4 MW。最後針對乾濕兩式製造合成氣之製程進行工程經濟分析暨其比較，吾人發現在合成氣產量610 kmol/h時乾式重組法之年製造成本 (COM) 為US$56.6 x 106/y，濕式重組法之年製造成本為US$53.2 x 106/y。
本論文之乾濕重組反應器設計皆以化工熱力學為基礎，主要應用 “Aspen Plus”與 “SuperTarget” 兩種化工程序軟體；前者用於程序合成與設計，後者則用於狹點分析及換熱器網路合成。

關鍵字

乾式重組 ； 蒸汽重組 ； 生質酒精 ； 二甲醚 ； 氫氣 ； 燃料電池

並列摘要

Due to the more and more attention of global demand for biomass energy, the yield of bioethanol continues in rapid rise. Excess production of bioethanol will be needed to find other ways out. Because the high hydrogen content in bioethanol, it is particularly suitable to produce hydrogen as a raw material. The aim in this study is at the design of dry and steam (wet) bioethanol reforming processes and its application in synthetic fuels and fuel cells, respectively.
Having carried out the sensitivity analysis using Aspen Plus software for the dry and wet bioethanol reforming reactors, we are able to select the operating conditions as (1) dry reforming: temperature is 960oC, pressure is 8 bar and the feed ratio of carbon dioxide to bioethanol is 1.3:1; (2) wet reforming: temperature is 700oC, pressure is 1 bar and the feed ratio of low-pressure steam to bioethanol is 6:1. In the application of the dry bioethanol reforming process, this study simulates a plant capacity of 27,000 metric tons per year of 99.9 mol% purity of dimethyl ether. Starting with bioethanol and carbon dioxide as the feeding materials, we are able to make syngas out of the reforming reaction; then, we employ the “one-step process” to accomplish the making of dimethyl ether. In regard to the distillation columns, we use a “three-step design procedure” to minimize the reboiler’s heat duty and save the energy. In addition, pinch technology is used to heat-integrating the plant-wide dimethyl ether synthesis. In the application of the wet bioethanol reforming process, we start with bioethanol and low-pressure steam as the feeding materials to make syngas. And then, we consider two different fuel cell applications: (1) we use pressure-swing adsorption technique to purify hydrogen. This high-purity hydrogen feeds into the fuel station for storage and provides fuel cell vehicles for use. We found that 5.6 kg of hydrogen can provide PEMFC vehicles with an output power of 113.2 kW; (2) another stream of high-hydrogen-content syngas is served for SOFC purpose in order to provide stationary power use. We found that 285 kmol/hr of hydrogen consumption rate can provide 4.4 MW power. Ultimately, as seen from the engineering economic analysis, we found the yearly cost of manufacture (COM) for dry and wet bioethanol reforming process is US$56.6 x 106/yr and US$53.2 x 106/yr, respectively.
It should be mentioned that, in this thesis, the design on the reactors system are based on the thermodynamic principle. Two kinds of software are utilized in the research－Aspen Plus and SuperTarget. The first is applied to implement the process synthesis and design; the second is applied to perform the pinch analysis and the synthesis of heat exchanger network.

並列關鍵字

Dry Reforming ； Steam Reforming ； Bioethanol ； Dimethyl Ether ； Hydrogen ； Fuel Cell

參考文獻

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