Study of design parameters affecting the performance of CO₂ purification units in oxy-fuel combustion

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• 作者：Marvine Tambe Besong^a ; ^{marvine.b@hotmail.co.uk} ; M. Mercedes Maroto-Valer^a ; ¹ ; ^{M.Maroto-Valer@hw.ac.uk} ; Adrian J. Finn^b ; ² ; ^{adrian.finn@costain.com}
• 关键词：Carbon capture and storage ; Oxy-fuel combustion ; Low temperature phase separation
• 刊名：International Journal of Greenhouse Gas Control
• 出版年：2013
• 出版时间：January, 2013
• 年：2013
• 卷：12
• 期：Complete
• 页码：441-449
• 全文大小：745 K

文摘

Oxy-fuel combustion is a promising technology for capturing carbon dioxide (CO₂) from power plants by generating a flue gas which is predominantly CO₂ and water vapour (which can be removed by condensation and drying). Other diluents (Ar, O₂ and N₂) and trace contaminants (SO₂, SO₃, NO, NO₂, CO, etc.) will also be present in the oxy-fuel derived CO₂-stream and have to be removed prior to transportation and storage. This flue gas composition makes low temperature physical separation a promising technology for CO₂ capture. The aim of this paper is to evaluate low temperature processes for producing high purity, high pressure CO₂ from oxy-fuel combustion flue gas through simulation and modelling in Aspen HYSYS using different patent applications filed by COSTAIN as basis. The processes are based on phase separation using simple flash units, integrated with the compression process. Excellent energy recovery is achieved by exploiting the cold duty of the process streams to supply the required refrigeration so that the overall power consumption is low.

The capture process shows good performance when treating flue gas of high CO₂ concentration, with purity of over 98 % , recovery rate over 93 % , and power consumption of 165 kWh/tCO₂ captured. For low CO₂ concentration (such as with a retrofit), a lower CO₂ recovery is obtained (approximately 85 % ) so that a small amount of further processing, e.g. by a physical solvent would be required to increase the CO₂ capture. The effect of design parameters on performance including CO₂ product purity, recovery rate and specific power consumption has been assessed. By optimizing process conditions, an optimum or near-optimum design has been generated taking into account the operating constraints of the equipment.