Analysis of reboiler heat duty in MEA process for CO₂ capture using equilibrium-staged model

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• 作者：Takahisa Yokoyama ; ^{takahisa@criepi.denken.or.jp}
• 关键词：Post-combustion ; CO2 capture ; Reboiler heat duty ; Components of heat ; Amine
• 刊名：Separation and Purification Technology
• 出版年：2012
• 期刊代码：78_13835866
• 类别：ce
• 出版时间：19 June, 2012
• 卷：94
• 期：Complete
• 页码：97-103
• 文件大小：731 K

摘要

There are several technology options for energy sectors that could reduce the amount of CO₂ emissions. At present amine-based absorption processes are most promising as CO₂ capture technologies. However amine-based CO₂ capture technologies are energy intensive and high in cost. There is continuous research and development for more effective solvents for CO₂ capture focusing mainly on lower heat requirement for regeneration. Although many studies for solvent development usually focus on solvents with low reaction heat, the regeneration heat of a solvent is interpreted approximately into three heat components (heat of reaction, sensible heat, and heat of vaporization). The heat energy for the regeneration process is usually supplied from the reboiler in the form of steam and the distribution of the heat energy to the three components depends on the key process parameters such as circulation rate and steam supply rate. In this study the overall performance of the MEA process in terms of CO₂ removal efficiency is examined at various process parameters through experimental work. There are negligible degradation and corrosion problems exhibited. Based on the results the distribution of regeneration heat is analyzed, in terms of the three heat components using an equilibrium-staged model. The model reaction process between CO₂ with MEA solvent in the CO₂ capture system was addressed based on CO₂-H₂O-MEA equilibrium. However for simplicity, the vapor-liquid equilibrium of H₂O-MEA system and the vapor-liquid equilibrium of CO₂-MEA are considered separately and then the two systems are coupled assuming they come into existence simultaneously. It is shown that focusing only on the heat of reaction which is an inherent property of a solvent is not sufficient to reduce the reboiler heat duty and that the sensible heat and the heat of vaporization must be taken into consideration to reduce the reboiler heat duty as they are strongly affected by operational parameters.