Evaluation of Newly Designed Polygeneration System with CO2 Recycle

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• 作者：Qun Yi ; Bingchuan Lu ; Jie Feng ; Yanli Wu ; Wenying Li
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：February 16, 2012
• 年：2012
• 卷：26
• 期：2
• 页码：1459-1469
• 全文大小：553K
• 年卷期：v.26,no.2(February 16, 2012)
• ISSN：1520-5029

文摘

A new coal-based polygeneration system with CO₂ recycle is proposed in this paper. With the gasified coal gas containing 23 vol % CO₂ and the coke oven gas containing 25 vol % CH₄ as the dual gas sources, the system mainly produces methanol, dimethyl ether, and electric power. The system adopts CO₂/CH₄ reforming to modify the C/H ratio of the syngas. Particularly, the CO₂, coming from the distillation tower, is recycled separately back to be a reactant during gasification and the resource gas in the reforming unit. As the CO₂ concentration in the exhausted gas from the distillation tower is more than 95 wt %, this system does not require a CO₂ separation unit. The system avoids the conventional water鈥揼as shift reaction that is used to adjust the ratio of C/H in the syngas, but fully uses the CO₂ produced from coal gasification, which solves the problems of CO₂ capture and storage. The performance of the whole system鈥檚 energy, CO₂ emission, and economics are analyzed by Aspen Plus 11.1 and Aspen Icarus 11.1 software. Results indicate that the new system realizes 11.5% increase of chemical energy, 1.3% increase of internal rate of return and 33.8% reduction of CO₂ emission at the expense of 8.4% of power output. Especially, the new system can save about 13鈥?8% on energy versus single product systems. The scheme in which CO₂ is recycled back to the gasifier and the reforming unit plays the most significant role in the comprehensive evaluation of energy utilization, CO₂ emission control, and economy benefits of the system.