基于MEA的燃煤电厂新型烟气CO2捕集工艺

Novel flue gas CO2 capture process for coal-fired power plants based on MEA

  • 摘要: 基于单乙醇胺(MEA)的燃烧后CO2捕集技术是当前研究最为深入的技术路线之一,但再生能耗过高仍是其规模化应用的主要障碍。而解吸过程中富液再生在解吸塔内需要大量中压蒸汽,为了降低富液再生的能耗需求,引入一种新型CO2捕集节能工艺,此工艺在富液预热工艺(RSP)的基础上加入贫蒸汽压缩工艺(LVC)。其中,富液预热器的热源为燃煤电厂脱硫前的烟气余热。为了体现RSP+LVC工艺的节能效果,研究使用Aspen Plus分别对基础工艺、贫蒸汽压缩工艺(LVC)、富液预热工艺(RSP)、富液预热工艺耦合贫蒸汽压缩工艺(RSP+LVC)进行建模,并对每个工艺能耗进行分析。结果表明,在RSP工艺基础上加入LVC工艺后,捕捉每kg CO2再沸器能耗降低20.9%。与基础工艺相比,RSP+LVC工艺可节省48.6%的再沸器热负荷(再生热能),并降低含电耗折算在内的26.06%总等效能耗。

     

    Abstract: Post-combustion CO2 capture using monoethanolamine (MEA) is one of the most extensively studied technological routes, yet excessive regeneration energy consumption remains a major barrier to its large-scale application. The regeneration of the rich solvent during desorption requires a significant amount of medium-pressure steam within the desorption tower. To reduce the energy consumption of rich solvent regeneration, a novel energy-saving carbon dioxide capture process was proposed. This process incorporated lean vapor compression (LVC) with the rich solvent preheating (RSP) process. The heat source for the rich solvent preheater came from waste heat of flue gas before desulfurization in coal-fired power plants. To demonstrate the energy-saving performance of the RSP+LVC process, Aspen Plus was used to establish models for the baseline process, LVC, RSP, and the coupled rich solvent preheating and lean vapor compression process (RSP+LVC). The energy consumption of each scheme was analyzed. The results indicated that incorporating LVC into the RSP process reduced reboiler energy consumption per kilogram of captured CO2 by 20.9%. Compared with the baseline process, the RSP+LVC process achieved a 48.6% reduction in reboiler thermal load (regeneration heat energy) and a 26.06% decrease in total equivalent energy consumption, including equivalent electricity consumption.

     

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