Packing Characterization: Advanced Model Development and Absorber Optimization

Packing Characterization: advanced model development and absorber optimization

by Chao Wang^1,2, Micah Perry², Gary T. Rochelle¹, Frank Seibert²

¹Department of Chemical Engineering, The University of Texas at Austin

²Separations Research Program, The University of Texas at Austin

Austin, TX 78712

Packing is widely used in post-combustion CO₂ absorption process because of its low pressure drop, good mass transfer efficiency, and ease of installation.  In this paper, three dimensionless mass transfer models based on absorption system were developed.  The effects of operating conditions and packing geometries were considered.  The new concept, Mixing Number was proposed to represent the packing geometry influence on mass transfer.  The three dimensionless mass transfer correlations developed in this work are:

 

   

The economic analysis of the absorber for a 250 MW coal-fired power plant was conducted, using the developed mass transfer models.  The purpose is to determine the optimal design and operating conditions for the amine scrubbing post-combustion absorber.  The Energy Cost (Energy) and the Annualized Capital Cost (CAPEX) for the absorber were calculated to determine the total processing cost as a function of the gas superficial velocity (u_G).  For reaction film controlled system such as CO₂ absorption, the optimum operating percent of flood is between 50 and 80% which is lower than the normal distillation design (usually between 70 and 90% of flood).  The optimal absorber design is to use packing with 200 to 250 m²/m³ surface area and high corrugation angle.